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An Evaluation of Biological Treatment Methods Used in Olive Mill
Wastewaters
Yakup Cuci
Kahramanmaras Sutcu Imam University, Engineering and Architecture Faculty, Dept. of Environmental
Engineering, Kahramanmaras, Turkey
cuci@ksu.edu.tr
Yağmur Uysal
Kahramanmaras Sutcu Imam University, Engineering and Architecture Faculty, Dept. of Environmental
Engineering, Kahramanmaras, Turkey
yuysal@ksu.edu.tr
Ece Ü Deveci
Kahramanmaras Sutcu Imam University, Engineering and Architecture Faculty, Dept. of Environmental
Engineering, Kahramanmaras, Turkey
ecedeveci@gmail.com
Özer Çınar
Kahramanmaras Sutcu Imam University, Engineering and Architecture Faculty, Dept. of Environmental
Engineering, Kahramanmaras, Turkey
ocinar@ksu.edu.tr
Abstract: Olive mill wastewater (OMW) is produced seasonally by a large number
of small olive mills scattered in Mediterranean countries. It has a high environmental
impact because of the concentration of its pollutant content and the quantity of waste
water produced. OMW contains high amounts of organic, inorganic and polyphenols.
It affects the water and soil quality, is toxic to plant life, and create odor nuisance
when disposed into the environment. The main problem regarding the disposal of
OMW is to find an environmentally friendly and economically viable solution.
Among the various techniques proposed, biological treatment appears to be
convenient from the economic point of view. The biological treatment of OMW is
quite difficult since it contains many complex substances, mostly when more easily
degradable carbon source is present in the medium. Several biological treatment
systems have been examined for the treatment of OMW, resulting in considerable
organic load and toxicity abatement. The present work aims to provide an updated
review of the current biological methods used in OMW treatment.
Keywords: Olive mill wastewater, OMW, biological treatment, aerobik systems,
anaerobic systems
Introduction
Mediterranean countries produce more than 98% of the world’s olive oil, which is estimated at over 2.5
million metric tons per year. About 75% is produced in the European Union (EU) (McNamara et al., 2008).
Olive oil mills are small agro-industrial units located mainly around the Mediterranean, Aegean and Marmara
seas that account for approximately 95% of the worldwide olive oil production (Ergüder et al., 2000). In the
olive growing countries of the Mediterranean area (Greece, Italy, Lebanon, Portugal, Spain, Syria, Tunisia and
Turkey) olive oil mill effluent production is more than 30 million m3 per year (Beccari et al., 1996). Olive mill
wastes are a significant source of potential or existing environmental pollution in these countries (Bejarano et al.,
1992). The difficulties of treatment of olive mill effluents are mainly related to high organic loading, seasonal
operation, high territorial scattering, and the presence of organic compounds which are hard to biodegrade such
as long-chain fatty acids and phenolic compounds.
525
�Olive oil mill wastewater (OMW) is formed from the water content of the fruit and water used in
washing and processes of olive oil extraction. The composition of OMW widely depends on the type of process
involved in obtaining the oil. OMW are dark-colored wastes and contain high amounts of many complex
substances that are not easily degradable (Borja et al., 1993; Sorlini et al. 1986). Generally, OMW can be treated
by conventional biological treatment methods or can be utilized as fermentation raw material for the production
of value added microbial products. However, this OMW also contains high concentrations of phenolic
compounds which inhibit microbial activity. This makes biological treatment or microbial fermentation difficult
(Massadeh and Modallal, 2008).
The uncontrolled disposal of OMW is becoming a serious environmental problem, due to its high
organic COD concentration, and because of its high content of microbial growth-inhibiting compounds, such as
phenolic compounds and tannins. The improper disposal of OMW to the environment or to domestic wastewater
treatment plants is prohibited due to its toxicity to microorganisms, and also because of its potential threat to
surface and groundwater (Ramos-Comenzana et al., 1996, Shaheen and Karim, 2007). When OMW are disposed
into the environment, they create odor, color and increased oxygen demand in water bodies. They also affect the
soil quality and plant life. Therefore, discharge of OMW into receiving media is not permissible unless
treatment.
Olive oil production and wastewater generation
The basic steps in production of olive oil are always the same. Batch and continuous processes are the
main methods used in the system. The first step in the oil production process is cleaning the olives and removing
the stems, leaves, twigs, and other debris left with the olives. The second step is produced olive oil by crushing
olives and extracting the oil by stone mills, metal tooth grinders, or various kinds of hammer mills or chemical
means (Dalis et al. 1996). The olive paste generally stays under the stones for 30 to 40 minutes. The purpose of
crushing is to tear the flesh cells to facilitate the release of the oil from the vacuoles. Mixing the paste for 20 to
45 minutes allows small oil droplets to combine into bigger ones. The paste can be heated or water added during
this process to increase the yield, although this generally results in lowering the quality of the oil. The next step
consists in separating the oil from the rest of the olive components (Azbar et al. 2004). This used to be done with
presses and centrifugation except in old facilities. The oil is then left in tanks or barrels where a final separation.
Sometimes the produced oil will be filtered to eliminate remaining solid particles that may reduce the shelf life
of the product.
Finally, possible additional processing steps include refining the oil to reduce its acidity and improve
flavor by alkali or steam processing; bleaching the oil to reduce chlorophyll, carotenoids, residual fatty acids,
and pesticides using kieselguhr, activated carbon, or synthetic silica treatment, and deodorization to reduce odors
with the use of activated carbon. The olive oil production processes are summarized in Figure 1.
Figure 1. Olive oil production processes (Azbar et al., 2004).
The remaining paste still contains a small quantity (about 2-6%) of oil that cannot be extracted by
further pressing, but only with chemical solvents. This is done in specialised chemical plants, not in the oil mills.
Olive oil production processes mainly differ in the process water requirements. A two-phase plant involves two
phases and much less additional water is used than in the three-phase process. Generally, one tone of olives
526
�yields one/two tones of OMW, according to the oil extraction process used. The continuous process uses about 2
L of water for kg of olives while the discontinuous one requires much less. Although the composition is
dependent on the process used, the olive mill wastewater is a stable emulsion constituted by ‘‘vegetation waters’’
of the olives, water from the processing, olive pulp and oil.
Parameter
Conventional press process
Three-phase process
4.5–5.0
12
10.5
1.5
0.1
120–130
90–100
2–8
5–2
1.0–1.5
1
1.0–2.4
0.03–10
4.7–5.2
3
2.6
0.4
0.9
40
33
1.0
0.28
1.0
0.37
0.5
0.5–2.3
pH
Total solids, %
Volatile suspended solids, %
Mineral suspended solids, %
Suspended solids, %
Chemical oxygen demand, g/L
Biochemical oxygen demand, g/L
Sugars, %
Total nitrogen, %
Polyalcohols, %
Pectin, tannin, %
Polyphenols, %
Oil and grease, %
Table 1. Characteristics of Wastewaters (Azbar et al., 2004)
An estimated 10–30 million m3 of OMW is generated every year from the production of olive oil. The
organic fraction of OMW includes sugar, tannins, polyphenols, polyalcohols, pectins and lipids (Capasso et al.,
1995). Most of the problems associated with OMW pollution can be attributed to the phenolic fraction. More
than 30 different phenolic compounds have been identified in OMW and the types and concentrations of
phenolics reported in OMW vary tremendously. In fact, phenolic compounds are responsible for several
biological effects, including antibiosis and phytotoxicity (Dalis et al. 1996). The antimicrobial activity is
principally due to phenolic compounds such as tyrosol and hydrotyrosol. Another negative property of OMW is
its extremely high organic content. Generally OMW has BOD values ranging between 12,000 and 63,000 mg/L
and COD values between 80,000 and 200,000 mg/L. These concentrations are approximately 400 times higher
than municipal sewage (Al-Malah et al., 2000). As microorganisms present in the environment consume these
materials, oxygen will be depleted from the water with adverse effects on the aquatic media. Common disposal
practices for OMW include direct discharge into soils or streams and use of evaporation ponds or lagoons. (AlMalah et al., 2000; Galli et al., 1997).
Biological treatment processes
Treatment processes must be efficient, allow for easy and economical operation in small-scale farm
settings, and consider the seasonality and the distribution of olive oil production. Therefore, a variety of
biological methods (e.g., aerobic or anaerobic bioreactors, composting) and microorganisms for treatment of
OMW have been tested, and reviewed by many researchers to remove the dark coloration, reduce the organic
load and remove phytotoxic compounds (Capasso et al. 1995).
Aerobic processes
Aerobic biological processes are commonly used in the treatment of organic wastewaters for achieving
high degree of treatment efficiency, while in anaerobic treatment, considerable progress has been achieved in
anaerobic biotechnology for waste treatment based on the concept of resource recovery and utilization while still
achieving the objective of pollution control (Chan et al. 2009). Using a simple aerobic treatment for OMW is not
effective because of the its characteristics. However, biological treatment is possible when a combination of
aerobic and anaerobic methods is applied, especially when it is diluted with municipal wastewater.
A number of different aerobic microorganisms have been tested in aerobic processes to treat OMW,
including Bacillus pumilus, Arthrobacter sp., Azotobacter vinelandii, Pseudomonas putida and Ralstonia sp. and
various bacterial consortia (McNamar and et al., 2008). Several studies of aerobic degradation of OMW have
focused on A. vinelandii. For example, Papadelli et al. (1996) isolated a strain of A. vinelandii from soil treated
with OMW. Eventually, 490% removal of phytotoxic compounds from OMW was achieved using this strain
(Ehaliotis et al., 1999; Piperidou et al. 2000).
527
�A number of studies have also utilized bacterial consortia coming from activated sludge, commercial
communities, soil, and wastewater. Bioremediation of OMW using aerobic consortia has been quite successful in
these studies, achieving significant reductions in COD (up to 80%) and the concentration of phytotoxic compounds, and complete removal of some simple phenolics.
Aerobic treatment has been also carried out in the presence of various strains of fungi such as white rot
fungi (including the edible mushrooms Lentinula and Pleurotus), Basidiomycetes sp. and Aspergillus niger and
several different yeasts. In addition to reduction of COD and removal of simple phenolics, fungi are also
effective at reducing coloration of OMW. The different biological treatments lead to very variable reductions in
COD and polyphenol levels depending on the performance of the strains selected for use.
Anaerobic processes
The anaerobic digestion is a biological process in which a complex community of microorganisms work
in a stable, self-regulating steady state converting waste organic matter into a mixture of carbon dioxide and
methane gases (Kaspar and Wuhrmann, 1978; Zeikus, 1980; Gujer and Zehnder, 1983; Speece, 1983; Sterling et
al., 2001). Anaerobic treatment is considered as a cost-effective alternative, if compared to aerobic treatment
especially for high organic industrial wastewater. Anaerobic digestion has a great number of advantages: low
nutrient requirements, energy savings, generation of low quantities of sludge, excellent waste stabilization,
production of biogas (methane) without the requirement of pre-treatments of the residues (Kang and Weiland,
1992; Weiland, 1993; Yadvika et al., 2004).
OMW is an effluent of the olive oil extraction process. The large volumes involved, along with the high
phenolic content and chemical oxygen demand, cause major environmental problems. However, the seasonal
production and high organic loading of OMWs make anaerobic treatment a very attractive option for these
wastes. Furthermore, production of much less biosolids (sludge) and biogas as a valuable end product, which
may offset the associated treatment costs, further add to the positive aspects of anaerobic treatment (Ergüder et
al., 2000). Anaerobic digestion processes produces useful energy and result in a net reduction in CO2 emissions.
Another advantage of anaerobic digestion is that a digester can be started up after more than eight months under
non-feeding conditions (Tsonis and Grigoropoulos, 1993), and is thus suitable for the treatment of seasonal
wastes such as OMW. The low rate anaerobic sludge blanket type reactor is considered as the most efficient
anaerobic reactor for the treatment of OMW.
Anaerobic digestion is usually the basic biological process for OMW treatment since it has many
advantages compared to aerobic treatment. These include no aeration requirements, lower sludge production,
lower nutrient requirements, the production of methane gas, and the quick recovery of anaerobic systems that
have been dormant for a long time (Droste, 1997). The last point is particularly important, as the treatment unit
will be without wastewater for about 8-9 months.
In the last decade, most of the research conducted on OMW treatment has been focused on the use and
development of anaerobic methods and bioreactors that can remove efficiently the high organic load (Boari et al.,
1984; Borja et al., 1992; Hamdi, 1995; Andreozzi et al., 1998) as well as reduce the toxicity of microorganismsinhibiting materials present in OMW (Paredes et al., 2001). It has been reported that anaerobic bacteria
decompose organic materials in a three-stage process emman et al., 1997). In the first stage, anaerobic bacteria
degrade complex organic materials into simpler compounds; namely, polysaccharides and polyphenols are
converted to their monomers (monosaccharides and phenols, respectively). During the second stage, acetogenic
bacteria convert the phenols and the monosaccharide into organic acids, such as acetic, lactic and formic acids
and alcohol. Finally, in the third stage, methanogenic bacteria, which are characterized by their sensitivity to pH,
convert the organic acids into biogas (a mixture of 60–80% methane and other gases, mainly carbon dioxide).
The presence of compounds toxic to methanogens in OMW appears to be a significant problem for
anaerobic digestion of OMW. The presence of phenolics limits the effectiveness of aerobic or anaerobic
treatment of this wastewater. Minimising the effects caused by high concentration of phenolics, OMW must be
diluted prior to either aerobic or anaerobic processes. Although dilution decreases the concentration of the toxic
compounds present in wastewater, making it easier to reach the required standards for the final effluent, it also
causes an increase in waste volume, which is not desired (El-Gohary et al., 2009).
A lot of researches were made for the anaerobic treatment of OMW in the literature. Some of them was
summarized in here: For example, Boari and Mancini (1990) studied the biological treatment of olive mill
effluent wastewater. They studied the effect of sedimentation, coagulation, followed by aeration. They also
studied BOD, COD, and suspended solids as main parameters and found that the removal percentage of organics
was higher than 90%. Their results using anaerobic digesters showed 70% removal of COD, and more
economical operation. Hayek et al. (1996) reduced the COD by 75% using upflow anaerobic sludge blanket
(UASB) reactor.
Ergüder et al. (2000) reported that OMWW could be treated anaerobically with high efficiencies (85.4–
93.4%) and treatment of 1 L OMWW by anaerobic methods resulted in production of 57.1±1.5 L of methane gas
528
�(i.e. 413 mL of methane gas was produced from degradation of 1 g of COD found in olive mill waste water).
Authors concluded that olive mill wastes can be treated under anaerobic conditions leading to production of
biogas in significant amounts.
Reductions in COD from 70% to 89% have been reported for anaerobic processes (Borja et al., 1996;
Marques et al., 1997; Marques, 2001). In addition to a substantial reduction of COD, Dalis et al. (1996) reported
large reductions (475%) in the concentrations of both toxic phenols and volatile fatty acids using a two stage
anaerobic reactor with an inoculant obtained from a domestic wastewater facility. In contrast, other studies have
reported that the build up of recalcitrant phenolics (e.g., condensed tannins, Zouari and Ellouz, 1996) as well as
the presence of long-chain fatty acids (Hwu and Lettinga, 1997) in anaerobic reactors inhibited microbial activity.
Subuh (1999) has conducted anaerobic digestion of OMW using laboratory scale Up-flow Anaerobic
Sludge Blanket (UASB) reactor. He proved that removal efficiency of the soluble fraction of COD reached 76%
using the UASB. Sabbah et al (2001) have evaluated different techniques for the treatment of OMW including
aerobic and anaerobic combined with physical treatment methods. Different types of reactors were checked such
as stirred-tank reactor, fluidized-bed reactor, and UASB reactor. UASB has showed a promising technique for
anaerobic treatment of OMW.
The anaerobic wastewater treatment processes have been tested for the treatment of olive mill effluents
in pilot scales. They have been tested in large scales as well, but only in combination with aerobic processing. A
multistage system with first an anaerobic stage and a sequential aerobic treatment stage has been investigated by
Steegmans (Steegmans, 1987). Sabbah et al. (2001) found that removal of the phenolic compound and possibly
other toxic materials that inhibit the growth of microorganisms using in the primary treatment step contributes
significantly on increasing the efficiency of anaerobic digestion.
Anaerobic digestion of unmodified OMW have been concerned with problems such as high toxicity and
low biodegradability and acidification of the reactor (Boari et al. 1984; Borja et al. 1992). However, the
efficiency of anaerobic digestion was increased when preceded by a pretreatment step. Several treatment
methods can be used as pretreatment of OMW such as physical (flotation, membrane seperation, gravitty settling,
ultrafiltration, centrifugation, coagulation etc.) and chemical (such as fenton oxidation processes) and biological
(aerobic, composting). For example, pretreatment of OMW by previously aerobic fermentation with Aspergillus
niger (Martin et al., 1991) and Geotrichum candidum (Beccari et al., 1999) could reduce residence time required
for anaerobic process. Selective preremoval of inhibitors such as lipids and poly phenols through lime or
lime/bentonite addition followed by phase separation before anaerobic digestion as a chemophysical treatment
has been studied (Box, 1983). Similarly, Azbar et al. (2008) compared the methane production in an anaerobic
digester fed with either raw or chemically pretreated OMW. They found over 80% increase in biogas production
when digesting OMW after chemical pretreatment. Accordingly, it has been concluded that, the anaerobic
biodegradability of OMW could be significantly enhanced by chemical pretreatment. El-Gohary et al. (2009)
reported that an integrated system consisting of catalytic oxidation using Fenton’s in combination with a two
stage anaerobic post-treatment (classical UASB followed by hybrid UASB) is recommended for treatment of
olive mill wastewater. The use of Fenton’s reaction as a primary treatment of OMW enhances the efficiency of
anaerobic digestion.
Conclusion
Generation of OMW in the Mediterranean region has a significant environmental impact and the high
organic polluted OMW affects the soil, groundwater and watercourses. Besides, the seasonal nature of olive oil
production, the geographic dispersion of mills and economic limitations for cost effective treatment all present
significant challenges in designing treatment options for OMW. However, OMWis not managed properly, due to
the fact that there is at present no reliable management plan. Therefore, a shift in current management schemes is
required that focuses on both the sustainable conservation of water resources in the Mediterranean region and on
the development of a cost-effective management method for OMW. Overall, the incorporation of biological
processes provides some of the most viable options for the treatment of OMW. Effective treatment methods will
be resulted in significant reductions in COD, phenolics and color allows safe and economical disposal of OMW
onto land or into surface waters.
References
Al-Malah, K., Azzam, M.O.J. & Abu-Lail, N.I. (2000). Olive mills effluent (OME) wastewater post-treatment using activated
clay, Separ. Puri. Technol. 20, 225–234.
529
�Andreozzi R, Longo G, Majone M & Modesti G. (1998). Integrated treatment of olive oil mill effluents, Water Res.,
32:2357–64.
Azbar, N., Bayram, A., Filibeli, A., Muezzinoglu, A., Sengul, F., & Ozer, A. (2004). A Review of Waste Management
Options in Olive Oil Production, Environmental Science and Technology, 34:209–247.
Azbar, N., Keskin, T. & Catalkaya, E.C. (2008). Improvement in anaerobic degradation of olive mill effluent (OME) by
chemical pretreatment using batch systems, Biochemical Engineering Journal, 38 (3), 379–383.
Beccari, M., Bonemazzi, E., Majone, M. & Riccardi C. (1996). Interactions between acidogenesis and methanogenesis in the
anaerobic treatment of olive mill effluents, Water Research, 30:183–9.
Beccari, M., Majone, M., Riccardi, C., Savarese, F. & Torrisi, L. (1999). Integrated treatment of olive oil mill effluent: effect
of chemical and physical pretreatment on anaerobic treatability, Wat. Sci.Tech., 40, 347.
Bejarano, M. & Madrid, L. (1992). Solubilization of heavy metals from a river sediment by a residue from olive oil industry,
Environmental Technology, 13:979–85.
Boari, G. & Mancini, I. M. (1990). Combined treatments of urban and olive mill effluents in Apulia, Italy, Water Sci. Tech.
22 235–240.
Boari, G., Brunetti, A. Passion, R. & Rozzi, A. (1984). Anaerobic digestion of olive mill wastewaters, Agricultural Wastes,
10, 161.
Borja, R., Alba, J. & Banks, C. J. (1996). Anaerobic digestion of wash waters derived from the purification of virgin olive oil
using a hybrid reactor combining a filter and a sludge blanket, Process Biochemistry, 31, 219–224.
Borja, R., Garrido, S. E., Martinez, L. & Ramos- Cormenzana, A. (1993). Kinetic study of anaerobic digestion of olive mill
wastewater previously fermented with Aspergillus, Process Biochemistry, 28, 397.
Borja, R., Martin, A., Maestro, R., Alba, J. & Fiestas, J. A. (1992). Enhancement of the anaerobic digestion of olive mill
wastewater by removal of phenolic inhibitors, Process Biochemistry, 27, 231.
Borja, R., Martin, M., Maestro, R., Alba, J. & Fiestas JA. (1992). Enhancement of the anaerobic digestion of olive mill
wastewater by the removal of phenolic inhibitors, Process Biochem;27:231–7.
Box, J.D. (1983). Investigation of the folin-ciocalteau phenol reagent for the determination of polyphenolic substances in
natural waters, Water Res., 17, 511.
Capasso, R., Evidente, A., Schivo, L., Orru, G., Marcialis, M.A. & Cristinzio, G. (1995). Antibacterial polyphenols from
olive oil mill waste waters, J. Appl. Bacteriol. 79, 393–398.
Chan, Y. J., Chong, M. F., Law, C. L. & Hassell, D.G. (2009). A review on anaerobic–aerobic treatment of industrial and
municipal wastewater, Chemical Engineering Journal, 155 (2009) 1–18.
Dalis, D., Anagnostidis, K., Lopez, A., Letsiou, I. & Hartmann, L. (1996). Anaerobic digestion of total raw olive-oil
wastewater in a two-stage pilot-plant (up-flow and fixed-bed bioreactors), Bioresource Technology, 57, 237–243.
Droste R.L. (1997). Theory and practice of water and wastewater treatment, John Wiley and Sons, Inc.
Ehaliotis, C., Papadopoulou, K., Kotsou, M., Mari, I. & Balis, C. (1999). Adaptation and population dynamics of Azotobacter
vinelandii during aerobic biological treatment of olive-mill wastewater. FEMS Microbiology Ecology, 30, 301–311.
El-Gohary, F., Tawfik, A., Badawy, M. & El-Khateeb, M.A. (2009). Potentials of anaerobic treatment for catalytically
oxidized olive mill wastewater (OMW), Bioresource Technology, 100 2147–2154.
Ergüder, H., Güven, E. & Denirer, G.N. (2000). Anaerobic treatment of olive mill wastes in batch reactors, Process Biochem.,
36 243–248.
Galli, E., Pasetti, L., Fiorelli, F. & Tomati, U. (1997). Olive-mill waste water composting: microbiological aspects, Waste
Manage. Res., 15, 323–330.
Gujer, W. & Zehnder, A.J. (1983). Conversion process in anaerobic digestion, Water Sci. Technol., 15, 123–167.
Hamdi M. (1995). Anaerobic digestion of olive mill wastewater, Process Biochem.,31:105–10.
530
�Hayek, B. Mosa, M. & Halasah, N. (1996). An experimental method for treatment of olive oil mills wastewater utilizing
upflow anaerobic sludge blanket (UASB) reactor, Proceedings of the Jordanian Chemical Engineering Conference II, Jordan,
2–4 pp. 64–81.
Hwu, C.-S. & Lettinga, G. (1997). Acute toxicity of oleate to acetate-utilizing methanogens in mesophilic and thermophilic
anaerobic sludges, Enzyme and Microbial Technology, 21, 297–301.
Kang, H. & Weiland, P. (1992). Ultimate anaerobic biodegradability of agro-industrial residues, Bioresour. Technol., 40,
245–250.
Kaspar, H. F. & Wuhrmann, K. (1978). Kinetics parameter and relative turnover of some important catabolic reactions in
digesting sludge, Appl. Environ. Microbiol., 36, 1–7.
Marques, I. P., Teixeira, A., Rodrigues, L., Martins Dias, S. & Novais, J.M. (1997). Anaerobic co-treatment of olive mill and
piggery effluent, Environmental Technology, 18, 265–274.
Marques, I.P. (2001). Anaerobic digestion treatment of olive mill wastewater for effluent re-use in irrigation, Desalination,
137, 233–239.
Martin, M., Borja, R., Garcia, I. & Fiestas, J. A. (1991). Kinetics of methane production from olive mill wastewater, Process
Biochem., 26:101–7.
Massadeh, M. I. & Modallal, N. (2008). Ethanol Production from Olive Mill Wastewater (OMW) Pretreated with Pleurotus
sajor-caju, Energy Fuels, 22 (1), pp 150–154.
McNamara, C. J., Anastasiou, C. C., O’Flaherty, V. & Mitchell, R. (2008). Bioremediation of olive mill wastewater,
International Biodeterioration & Biodegradation, 61, 127–134.
Papadelli, M., Roussis, A., Papadopoulou, K., Venieraki, A., Chatzipavlidis, I., Katinakis, P. & Balis, K. (1996). Biochemical
and molecular characterization of an Azotobacter vinelandii strain with respect to its ability to grow and fix nitrogen in olive
mill wastewater, International Biodeterioration & Biodegradation, 38, 179–181.
Paredes, C., Bernal, M.P., Roig, A. & Cerarra, J. (2001). Effect of olive mill wastewater addition in composting of
agroindustrial and urban wastes, Biodegradation,12:225–34.
Piperidou, C., Chaidou, C., Stalikas, C., Soulti, K., Pilidis, G. & Balis, C. (2000). Bioremediation of olive oil mill
wastewater: chemical alterations induced by Azotobacter vinelandii, Journal of Agriculture and Food Chemistry, 48, 1941–
1948.
Ramos-Cormenzana, A., Juarez-Jimenez, B. & Garcia-Pareja, M.P. (1996). Antimicrobial activity of olive mill waste-waters
(alpechin) and biotransformed olive oil mill wastewater, International Biodeterioration & Biodegradation, 38, 283–290.
Sabbah, I., Marsook, T. & Basheer, S. (2001). Anaerobic systems for reducing the environmental impacts of olive-mill
wastewater, 9th World Congress, Anaerobic Digestion, Antwerpen-Belgium, 535- 540.
Speece, R.E. (1983). Anaerobic biotechnology for industrial wastewater treatment, Environ. Sci. Technol., 17, 416–427.
Steegmans, R. (1987). Abw sser aus der Oliven lgewinnung –Anfall, Problematik und Entsorgung – Gew sserschutz, Wasser,
Abwasser, Festschrift zur Emeritierung von Prof. Dr.-Ing., Dr. h.c. Botho B hnke. Gesellschaft zur Frderung der
Siedlungswasser- Wirtschaft. Bearbeitung Dr. rer. Nat. R. Schulze-Rettmer, Heft 95, Aachen.
Sterling Jr., M.C., Lacey, R.E., Engler, C.R. & Ricke, S.C. (2001). Effects of ammonia nitrogen on H2 and CH4 production
during anaerobic digestion of dairy cattle manure, Bioresour. Technol., 77, 9–18.
Subuh, Y. (1999). Anaerobic treatment of olive mills wastewater using Up-flow Anaerobic Sludge Blanket (UASB) reactor,
M.Sc. Thesis, An-Najah N. University, Nablus, Palestine.
Tsonis, S. & Grigoropoulos, S. (1993). Anaerobic treatability of olive mill wastewater, Water Science and Technology, 28 (2),
35–44.
Weiland, P. (1993). One- and two-step anaerobic digestion of solid agroindustrial residues, Water Sci. Technol., 27, 145–151.
Yadvika, S., Sreekrishnan, T.R., Kohli, S. & Rana, V. (2004). Enhacement of biogas production from solids substrates using
different techniques-a review, Bioresour. Technol., 95, 1–10.
Zeikus, J.G. (1980). Microbial population in anaerobic digestors. In: Stafford, D.A. (Ed.), First International Symposium on
Anaerobic Digestion, Scientific Press, Cardif, pp. 75–103.
531
�Zouari, N. & Ellouz, R. (1996). Toxic effect of coloured olive compounds on the anaerobic digestion of olive oil mill effluent
in UASB-like reactors, Journal of Chemical Technology and Biotechnology, 66, 414–420.
532
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An Evaluation of Biological Treatment Methods Used in Olive Mill Wastewaters
Author
Author
Cuci, Yakup
Uysal, Yağmur
Deveci, Ece Ü
Çınar, Özer
Abstract
A summary of the resource.
Olive mill wastewater (OMW) is produced seasonally by a large number of small olive mills scattered in Mediterranean countries. It has a high environmental impact because of the concentration of its pollutant content and the quantity of waste water produced. OMW contains high amounts of organic, inorganic and polyphenols. It affects the water and soil quality, is toxic to plant life, and create odor nuisance when disposed into the environment. The main problem regarding the disposal of OMW is to find an environmentally friendly and economically viable solution. Among the various techniques proposed, biological treatment appears to be convenient from the economic point of view. The biological treatment of OMW is quite difficult since it contains many complex substances, mostly when more easily degradable carbon source is present in the medium. Several biological treatment systems have been examined for the treatment of OMW, resulting in considerable organic load and toxicity abatement. The present work aims to provide an updated review of the current biological methods used in OMW treatment.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
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Keywords.
Conference or Workshop Item
PeerReviewed
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Evaluation of Residual Stresses in Heat Treated AISI 5115 and AISI 52100
Steels via Analysis of Instrumented Sharp Indentation Load-Unload Cycle
Osman Culha
Dokuz Eylul University, Faculty of Engineering
Department of Metallurgical and Materials Engineering, Turkey
osman.culha@deu.edu.tr
Seher Tas
Dokuz Eylul University, Faculty of Engineering
Department of Metallurgical and Materials Engineering, Turkey
seher.tas@ogr.deu.edu.tr
Mustafa Toparli
Dokuz Eylul University, Faculty of Engineering
Department of Metallurgical and Materials Engineering, Turkey
mustafa.toparli@deu.edu.tr
Abstract: In this research, heat treated AISI 5115 (16MnCr5) cementation and AISI 52100
roller bearing steels were investigated. The specimens that were prepared before and after
heat treatment application were sectioned via wire-erosion machine. Specimens were properly
sanded and polished to get a smooth surface. Optical micrographs of each specimen were
taken by a Nikon Eclipse ME 600 metallographic microscope. These specimens were then
examined by using a Dynamic Ultra Micro Hardness (DUH) tester under a set of maximum
loads of 200, 400, 600, 800, and 1000 mN. For each heat treated and non-heat treated
specimen subjected to load-unload cycle under the same amount of maximum load, load vs.
penetration depth curves were plotted. By comparing the resultant load-unload curves, types
of the residual stresses were determined. Individual calculations were made for tensile and
compressive residual stresses to obtain the residual stress values.
Introduction
Residual Stress after various product stages such as welding, casting, surface processing and heat
treatment process that remain in parts. Varieties relevant with welding manufacturing, casting, surface treatments
and heat treatment effect mainly reason become residual stress. Residual stress because of in part after
manufacturing will be applied external stress during service, effect with residual stress (Dilmeç et al., 2008). In
this case, contained residual stress in a part, real applied condition may be much different from estimated that
results obtained by analysis/calculate on part. Tensile and compressive residual stresses consist of thermal stress
resulting from cooling difference between surface and core of material. This stresses may be beneficial or
harmful to the material performance (Asi & Asi, 2003). While, tensile stresses decrease fatigue life of material
so early damage, compressive stresses act to increase fatigue life of materials. Successful heat treatment process
may hinge upon achieving not only the appropriate surface finish, hardness, but also a residual stress distribution
producing the longest component life
During surface hardened process such as cementation and nitruration, surfaces are heated in carbon or
nitrogen atmosphere. These of result, volume of surfaces grow up and compressive residual stresses are
becoming in the surfaces. Depending on rising hardened layer thickness in the cemented steel increase
compressive residual stresses. Therefore abrasion resistance and fatigue strength in parts of surfaces is increased
(Karataş et al., 2001). To understand the significance of these effects on the production of parts such as bearing
ball and gears, and to evaluate material's performance during service need to know level of residual stress.
There are many destructive and nondestructive methods in order to measure the residual stresses in
materials. Non-destructive residual stress measurement techniques make use of different characteristics of
samples in order to obtain residual stress. There are magnetic method, ultrasonic method, raman spectroscopy,
X-ray diffraction and neutron diffraction. The main principle of the destructive methods is that by removing
some part of the sample depending on the technique. Sahin et al. (2003) determined residual stresses near the
surface of the material by the hole-drilling strain-gage method. In addition, the contour method is one of the
308
�recent destructive residual stress measurement techniques. Turski and Edwards (2009) examined the
measurement of transverse residual stresses within the bead-on-plate weld specimen using the contour method.
Suresh and Giannakopoulos (1998) have first introduced indentation technique which is a destructive technique
for estimating residual stress. Comparing with traditional techniques, the depth-sensing indentation technique
provides a quick and effective method of measuring the residual stress field (Chen et al., 2006). In this
technique, experimentally determined the type and magnitude of residual stresses from automatically drawn
load-unload curves from computer which connected microhardness test equipment, can be easily calculated
residual stress. Being a destructive testing method, instrumented sharp indentation has been applied in recent
years as a technique to evaluate the inhomogeneously distributed residual stresses caused by plastic deformation
or thermal effects in welded, cast, surface processed and heat treated materials. By utilizing instrumented sharp
indentation, residual stresses produced by various different processes on material surfaces can be directly
measured. It’s evident through current studies that results obtained by using this technique are robust enough to
compare with other methods. As a fast and reliable means of residual stress evaluation, it’s believed that this
technique will become a common practice in the foreseeable future.
In the present study, subjected to heat treatment of AISI 5115 (16MnCr5) and AISI 52100 (100Cr6)
steels were measured in the bottom of surface the residual stresses using indentation techniques.
Instrumented Indentation Method
The microindentation technique (Nishibori et al., 1978; Dub et al., 2002) has been developed in some
decades, and the mechanical properties within a sub-micron or nano scale are widely discussed. The techniques
are expected to be useful for measurement of the mechanical properties of thin films or local structure of various
materials. While employing the instrumented indentation technique at nanoscale one can directly determine the
nanohardness, Young’s modulus and the deformation characteristics (Reibold et al., 2005). From the loading and
unloading curve the nature of elastic–plastic transition can be analyzed.
Elastic modulus E and microhardness H can be obtained with the load and penetration depth data (Uzun
et al. 2005). During indenter loading, test material is subjected to both elastic and plastic deformation. The three
key parameters needed to determine the hardness and modulus are the peak load (Pmax), the contact area (Ac) and
the initial unloading contact stiffness (S). Similar to the conventional microhardness testing, the micro
indentation hardness is usually defined as the ratio of the peak indentation load, Pmax, to the projected area of the
hardness impression, Ac, i.e.
P
Pmax
( Ac = 26.43hc 2 )
(1)
H = max =
2
Ac
26.43hc
Different approaches for deducing the contact depth, hc, from the resultant load displacement curve have been
purposed and perhaps the most widely used one is that of Oliver and Pharr (Oliver &.Pharr, 1992). The Oliver
and Pharr (1992) data analysis procedure begins by fitting unloading curve to an empirical power-law relation.
(2)
P = α(h − hf )m
where P is the indentation load, h is the penetration depth, hf is the final unloading depth and α and m are
empirically determined fitting parameters. Using the initial part of the unloading curve, both stiffness and contact
depth are determined by differentiating Eq. (2) at the maximum depth of penetration, h = hmax. Then, the stiffness
of the contact is given by
S=
2
dP
=
E r Ac
dh
π
(3)
Where Er is the reduced elastic modulus.
In this study, the Oliver and Pharr (1992) method was used to calculate the initial stiffness (S), contact depth (hc)
and hence reduced modulus (Er) and hardness (HV).
2
1 1 −ν 2 1 −ν 0
(4)
=
+
Er
E
Eo
Where E and ν are Young’s modulus and Poisson’s ratio for the specimen, and Eo and νo are the same
parameter for the indenter.
As explained above, instrumented indentation is characterized by a sharp rigid indenter which
mechanical properties are known (frequently made of a very hard material like diamond) penetrating normally
into a homogeneous solid where the indentation load, P, and displacement, h, are continuously recorded during
one complete cycle of loading and unloading (Figure 1).
309
�Figure 1: Schematic graph of the indentation load–depth curve (Son et al., 2003)
Measured residual stress is based on the calculation of the difference between the indentation contact
areas of with and without stressed surfaces by analyzing ‘‘indentation load–depth’’ data according to the below
equations (Suresh & Giannakopoulos, 1998):
For tensile residual stress
Ac/Ao = (1-(σr / ρave ))-1
For compressive residual stress
Ac/Ao = (1+(σr sinα / ρave )) -1
(5a)
(5b)
where Ac and Ao are the indentation contact areas with and without residual stress (σr), respectively. α is a
geometric factor, where a is related to the indentation angle of the indenter. If the Vickers pyramid indenter is
used α = 22o. ρave is the average contact pressure, ρave =Pmax/Amax
Depend on the type of residual stress (tensile or compressive) as shown in Figure 2 if the indentation
contact area ratio (Ac/Ao) is known then σr values can be calculated simply from Equation (1a) or (1b).
Figure 2: The indentation load-depth (P-h) curves for the surfaces with and without residual stresses.
We now seek to derive the effects of a compressive residual stress on the contact areas and indentation
penetration depths. Figure 2 schematically shows the load-depth curve for the indentation of the virgin material,
and that for the substrate with an equibiaxial compressive residual stress. Assume that the following loading
history takes place. The material with the residual stress is first indented with a load P1 which causes the indenter
to penetrate it by a depth h1. This point is denoted by the symbol X in Figure 2 (Suresh & Giannakopoulos,
1998)
Keeping the indentation depth h1 constant, let the indented material now undergo a complete relaxation
of the residual stress, i.e. let the residual stress relax from σxRo = σyRo 0 to zero at a fixed penetration depth, h1=h2.
In order for the average contact pressure pave to remain invariant, the equivalent plastic strain beneath the
indenter should be preserved, as noted earlier. Consequently, the change in the stress state of the material
beneath the indenter during the release of this compressive residual stress must be hydrostatic. The resulting
310
�tensile hydrostatic stress, σH, σxRo, σyRo, σzRo can be regarded as introducing an effective differential force of
magnitude σHfA in the z direction, i.e. in the direction of the applied indentation load, as shown in Figure 3,
where f= sinα. Thus, as the compressive residual stress, σxRo, σyRo is released and the point of indentation moves
from location X to location Y in the P-h curves in Figure 2, the contact force effectively decreases from P1 to P2
at a constant penetration depth, h1=h2. In summary, for a fixed indenter penetration depth and for X-Y in Figure
2,
P1-P2= σHfA=- σxRo fA= -σyRo fA
From the equation (2) can be obtained ratio (Ac/Ao) :
R
A σy
= 1 +
σu
Ao
−1
σy
.1 +
σu
E tan α
. 1 + ln
R
3σ y
−1
E tan α
.1 + ln
3σ y
(6)
where σy and σyR are the yield strengths of the surface with and without residual stress, respectively, σu is the
ultimate strength (Suresh & Giannakopoulos, 1998).
Figure 3: Schematic representation of residual stress while indenter is under contact position with material a) for
Suresh and Giannakopoulos (1998) b) for Atar et al. (2003)
Suresh and Giannakopoulos (1998) reported that according to the upper-bound solution of the
compressive residual stress, the magnitude of the force acting normal to the inclined faces of the indenter during
indentation is σrfA as shown in Figure 3a. Since α=22o for the Vickers pyramid indenter, the geometric factor f
=sinα is noted as 0.375 theoretically. In the present study, the geometric factor was calculated experimentally as
1, which corresponds to an a value of 90o. This indicates that the impelling force having a value of σrA is acting
against the applied indentation load in the direction of indentation (perpendicular to the indentation contact area)
rather than the component of the residual stress acting normal to the inclined faces of the indenter. Thus, Net
indentation load =applied indentation load- impelling force as shown in Figure 3b. Therefore, for the calculation
of the residual compressive stress in materials by utilizing the Vickers pyramid indenter, Eq. (5b) should be
modified as (Atar et al., 2003):
A σ r
= 1 +
Ao ρ ave
−1
(7)
In this study, we draw attention to residual stress calculation of AISI 5115 and 52100 bulk material after heat
treated by indentation method. In this context, Both Atar et al. (2003) and Suresh & Giannakopoulos (1998)
method were used and compare with each other. Firstly, mechanical properties of materials were examined by
Shimadzu Dynamic Ultra-micro hardness test machine for estimating Young’s modulus due to load-unload
sensing analysis, in addition to mechanical investigation hardness-force and Young’s modulus-force curves of
the coatings were obtained. Load depended elastic modulus and hardness were obtained at 200 mN, 4000 mN,
600 mN, 800 mN and 1000 mN applied peak loads. After obtaining characteristics indentation curves under
applied loads of different quality virgin and heat treated materials, residual stresses were calculated with two
different indentation approaches.
Experimental Study
High carbon through-hardening steel AISI 52100 and case-carburized low carbon steel AISI 5115 are
used for antifriction bearings and gears, shafts, axles, cam. (Stickels & Janotik, 1980). Case-carburized parts and
311
�cemented steels develop compressive residual stresses at the surface. Compressive residual stresses at the surface
are beneficial performance of material, which during service.
In this experimental study, samples were manufactured from rods of an AISI E52100 ball bearing steel
and AISI 5115 (16MnCr5) carburizing steel. This samples chemical composition is given in Table 1 and Table 2.
The samples turned a disk with a thickness of 0.50mm and a diameter of Ø22mm after the samples were cut
from rod at a wire EDM machines samples to measure with and without the stresses before and after heat
treatment processing, respectively.
C (%)
0.966
Si(%)
0.236
Mn(%)
0.468
P(%)
0.008
S(%)
0.005
Cr(%)
1.580
Ni(%)
0.107
Cu(%)
0.110
Table 1: Chemical composition of the AISI 52100(100Cr6) ball bearing steel
C (%)
0.14-0.16
Si (%)
0.15-0.40
Mn(%)
1.0-1.30
P(%)
0.035
S(%)
0.05
Cr(%)
0.8-1.1
Table 2: Chemical composition of the AISI 5115 (16MnCr5) carburized steel
Carburizing programs were carried out in gas atmosphere at 960°C and 840°C for16MnCr5 and 100Cr6,
respectively at heat treatment. During the carburizing process the carbon potential of batch furnaces was adjusted
to 1.2 % C and 0.45 % C at 960°C and 840°C and then reduced to maintain the final surface carbon content of
the 16MnCr5 specimen below 0.8% C and but increased above 0.8% C of the final surface carbon content for
100Cr6 specimen. Specimens were processed in the direct quenched condition and then were tempered at 80°C
for 20-30 minutes. Surface preparation of the disks was done by grinding and polished.
These specimens were then examined by using a Dynamic Ultra Micro Hardness (DUH) tester under a
set of maximum loads of 200, 400, 600, 800, and 1000 mN. For each heat treated and non-heat treated specimen
subjected to load-unload cycle under the same amount of maximum load, load vs. penetration depth curves were
plotted. During the test load-depth (P-h), elasticity modulus and hardness data of each samples were recorded
with connected computer. By comparing the resultant load-unload curves, types of the residual stresses were
determined. Individual calculations were made for tensile and compressive residual stresses to obtain the residual
stress values.
Results and Discussion
The mechanical properties such as hardness, Young’s modulus, fracture toughness, ductility, etc are
important parameters for industrial application. Shimadzu Dynamic Ultra Micro Hardness Testing machine is
used for determination hardness variation and young modulus of FeB layers. Different loads such as 200, 400,
600, 800, 1000 mN are applied for determination of hardness and Young’s modulus. Loading and unloading
curves of AISI 5115 and 52100 before and after heat treated materials are shown in Figure 4 and 5. According to
the results, compressive characteristics residual stresses were obtained for each material.
312
�1.
(b)
(c)
(d)
(e)
Figure 4: Loading- unloading curves of AISI 5115 quality steels under a) 200 mN b) 400 mN c) 600 mN d) 800
mN e) 1000mN
313
�(a)
(b)
(c)
(d)
(e)
Figure 5: Loading- unloading curves of AISI 52100 quality steels under a) 200 mN b) 400 mN c) 600 mN d)
800 mN e) 1000mN
The calculated Young’s modulus of AISI5115 and AISI52100 quality steels with and without stress
under different applied peak loads are shown in Figure 6. According to the results, Young’s moduli of stressed
and unstressed materials are decreased with increasing applied loads.
314
�AISI 5115 with Stress E
300,00
AISI 5115 Without Stress E
AISI 52100 With Stress E
E (GPa)
250,00
AISI 52100 Without Stress E
200,00
150,00
100,00
50,00
0,00
0
200
400
600
800
1000
1200
Force (mN)
Figure 6: Young’s modulus variations of AISI 5115 and AISI 52100 with and without stress
35,00
10,00
AISI 5115 with Stress H
30,00
Yield Stress GPa)
H (GPa)
AISI 5115 Yield Stress Without Stress
8,00
AISI 52100 With Stress H
25,00
AISI 5115 Yield Stress With Stress
9,00
AISI 5115 Without Stress H
AISI 52100 Without Stress H
20,00
15,00
10,00
5,00
AISI 52100 Yield Stress With Stress
AISI 52100 Yield Stress Without Stress
7,00
6,00
5,00
4,00
3,00
2,00
1,00
0,00
0
200
400
600
800
1000
1200
0,00
0
200
Force (mN)
400
800
1000
1200
Force (mN)
a)
b
1,50
18,00
AISI 5115 With Stress
AISI 5115 Ultimate Stress With Stress
16,00
1,30
AISI 5115 Ultimate Stress Without Stress
14,00
AISI 52100 Ultimate Stress With Stress
12,00
AISI 52100 ultimate Stress Without Stress
AISI 5115 Without Stress
AISI 52100 with Stress
hr/hmax
Ultimate Stress (GPa)
600
10,00
8,00
1,10
0,90
6,00
0,70
4,00
0,50
2,00
AISI 52100 Without Stress
0,30
0,00
0
200
400
600
800
1000
1200
0
200
400
600
800
Force (mN)
Force (mN)
315
1000
1200
�c)
d)
450,00
AISI 5115 With Str ess
400,00
AISI 5115 Without Stress
350,00
AISI 52100 With Stress
AISI 51200 Without Stress
C (GPa)
300,00
250,00
200,00
150,00
100,00
50,00
0,00
0
200
400
600
800
1000
1200
Force (mN)
e)
Figure 7: a) Hardness b) Yield Stress c) Ultimate Stress d) hr/hmax and e) C –Force curves of AISI 5115 and
52100 quality steel (with and without stress)
Hardness study of samples is shown in Figure 7 a). When the applied loads increased from 200 to 1000
mN, hardness values of AISI 5115 and 52100 quality steel were decreased from 5,40 to 3,64 GPa and 4,38 to
3,38 GPa, respectively. After heat treatment regime and compressive residual stress (reduction of contact area),
hardness of samples increased as 26,60 to 14,69 GPa and 24,92 and 16,09 GPa for AISI 5115 and 52100 quality
steels under same applied loads.
Yield and ultimate stress of samples were determined by analyzing the indentation load–depth data
according to the step by step procedure (Suresh & Giannakopoulos, 1998). This calculation procedure was
applied for both AISI 5115 and 52100 quality steels and their heat treated samples. Yield and ultimate stress
values differences between virgin and heat treated samples were given in Figure 7 b) and c). Each result
influenced from applied loads and indentation size effect active in this model.
hr/hmax and C values of samples is indicated the elastic properties. C is active in loading part of
indentation curve as P=Ch2. As shown in Figure 5 and Figure 7 e), C values of heat treated samples increased
depending applied loads.
316
�100,00
Residual Compressive Stress (GPa)
A ISI 5 11 5 Compre ssive Res idu al Stre ss S tress by At ar (2 00 3)
90, 00
A ISI 5 11 5 Compre ssive Res idu al Stre ss b y S ure sh an d Gia nn ak op ou lo s
(1 99 8)
A ISI 5 21 00 co mpre ssive Resid u al S tres s b y At ar (2 00 3 )
80, 00
A ISI 5 21 00 Co mpress ive Re sid ua l S tress by Su resh a nd G ian na ko po u los
(1 99 8)
A ISI 5 11 5 Compre ssive Res idu al Stre ss b y Te o . X RD
70, 00
60, 00
50, 00
40, 00
30, 00
20, 00
10, 00
0,00
0
200
40 0
600
800
1 000
1200
Force (mN)
Figure 8: Residual Compressive Stress variations (for two different theories) of AISI 5115 and 52100 quality
steels under different applied loads
The residual stress values of AISI 5115 and 52100 quality steels determined by the instrumented
indentation method were found and represented in Figure 8. Atar et al. (2003) and Suresh & Giannakopoulos
(1998) methods were applied to indented samples and calculation results showed that differences of contact area
calculation is directly effect the residual stress results.
References
Asi, O. & Asi, D. (2003). An investigation of residual stresses developed in carburized SAE 8620 steel. Gazi University
Journal of Science 16, 725-732.
Atar, E., Sarıoğlu, C. et al. (2003). Residual stress estimation of ceramic thin films by X-ray diffraction and indentation
techniques. Scripta Materialia 48, 1331-1336
Chen, X., Yann, J., Anette, M.K. (2006). On the determination of residual stress and mechanical properties by indentation.
Materials Science and Engineering: A 46, 139-149.
Dilmeç, M., Yiğit, O., Halkacı, H.E.(2008). Measurement of residual stresses with layer removal method and comparison
with other methods. Mühendis ve Makine 49, 20-27.
Dub, S., Novikov, N., Milman, Y. (2002). The transition from elastic to plastic behaviour in an Al-Cu-Fe quasicrystal studied
by cyclic nanoindentation. Philosophical Magazine A 82, 2161–2172.
Karataş, Ç., Fetullayev, E., Kafkas, F. (2001). The research into the residual stresses on the root’s teeth of a gear wheel made
of AISI 5115 steel. Journal of Faculty Engineering Architecture Gazi University 16, 9-18.
Oliver, W.C. & Pharr, G.M. (1992). An improved technique for determining hardness and elastic-modulus using load and
displacement sensing indentation experiments. Journal of Materials Research 7, 1564-1583.
317
�Nishibori, M. & Kinoshita, K. (1978). Ultra-microhardness of vacuum-deposited films I: Ultra-microhardness tester. Thin
Solid Films 48, 325-331.
Reibold, M., Belger, A. et al. (2005). The impact of nanoindentation at room temperature upon the real structure of decagonal
AlCoNi quasicrystals. Physica Status Solidi A-Applications and Materials Science 202, 2267–2276.
Sahin, S., Toparli, M. et al. (2003). Modelled and measured residual stress in a biomaterial joint. Journal of Materials
Processing Technology 132, 235-241.
Stickels, C.A. & Janotik, A.M. (1980). Controlling residual stress in 52100 bearing stress by heat treatment. Metallurgical
and Materials Transactions A 11, 467-473.
Suresh, S. & Giannakopoulos A.E. (1998). A new method for estimating residual stresses by instrumented sharp indentation.
Acta Materialia 46, 5755-5767.
Turski, M. & Edwards, L. (2009). Residual stress measurement of a 316l stainless steel bead-on-plate specimen utilising the
contour method. International Journal of Pressure Vessels and Piping 86, 126-131
Uzun, O., Kölemen, U. et al. (2005). Modulus and hardness evaluation of polycrystalline superconductors by dynamic
microindentation technique. Journal of the European Ceramic Society 25, 969-967.
318
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Title
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Evaluation of Residual Stresses in Heat Treated AISI 5115 and AISI 52100 Steels via Analysis of Instrumented Sharp Indentation Load-Unload Cycle
Author
Author
Culha, Osman
Tas, Seher
Toparli, Mustafa
Abstract
A summary of the resource.
In this research, heat treated AISI 5115 (16MnCr5) cementation and AISI 52100 roller bearing steels were investigated. The specimens that were prepared before and after heat treatment application were sectioned via wire-erosion machine. Specimens were properly sanded and polished to get a smooth surface. Optical micrographs of each specimen were taken by a Nikon Eclipse ME 600 metallographic microscope. These specimens were then examined by using a Dynamic Ultra Micro Hardness (DUH) tester under a set of maximum loads of 200, 400, 600, 800, and 1000 mN. For each heat treated and non-heat treated specimen subjected to load-unload cycle under the same amount of maximum load, load vs. penetration depth curves were plotted. By comparing the resultant load-unload curves, types of the residual stresses were determined. Individual calculations were made for tensile and compressive residual stresses to obtain the residual stress values.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
Q Science (General)
-
https://omeka.ibu.edu.ba/files/original/64e403b87d00af8ef695305780754619.pdf
f99eb60585efdd9939f7e9ff2455982b
PDF Text
Text
2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
The Effects of Financial Failure in Business Inventory Management
Mehmet CĠVAN
Asst. Prof. Dr.,Gaziantep University, Faculty of Economics and Administrative Sciences
Department of Business Administration
mehmetcivan27@hotmail.com
Faruk DAYI
Research Assistant,Gaziantep University, Faculty of Economics and Administrative Sciences
Department of Business Administration
fdayi@gantep.edu.tr
Abstract: Global competition increases, inventory management businesses on the
importance increased. Goods and services to sell in the global market, the unit costs
low, the production efficiency is need to higher..Stok management, raw material
supply whether manufactured and offered to customers are far, production and
distribution activities is fundamental. The amount of inventory the company's total
assets 40% to 60% in the thought, the investment in a significant portion of the
inventory allocated to the will see. Especially,in trade businesses inventory, is
majority of the balance sheet active.In the industry businesses the fixed assets
,investment is well ossified in inventory that will see. That in a state enterprise
liquidity is insufficient and receivables collected in both high-cost inventories
disposal are challenges. Daily operations to meet cash asset management could not,
pay their debts to be forced, commercial reputation damage to the liquidation or
even bankruptcy process go through a process to enter will result.
Introduction
The amount of inventory, 40% of the total assets of businesses to be between 60% and is considered, a
significant portion of investments allocated to inventories will be observed. Connected to the large amounts of
money from inventories, short-term debt funding may be provided by increasing the rate of inventory turnover.
The company failed financially, the inventory turnover rate is low, the lack of sales will result in the desired
level, so businesses will experience liquidity problems. Financially failing companies, the financial measures
taken unable bankruptcy to go a long to enter the business to invest in the shareholder losses, and direct the
national economy of full employment to reach defended. economic state that is strong businesses, this negative
situation that much is not affected unlike grow more powerful as the crisis are .This study will examine the
subject of inventory management and financial failures, business failures fall into the cause of the factors to be
investigated.
Financial Perspective to Inventory Management of Businesses
In business inventory management major makes many reasons. Especially in business inventory
investment is considerably high, usually ossified investments and consisting of a very high cost. Especially
manufacturing and trading companies operating in the subject of the inventory represents that we think the
presence of a large portion of the inventories has created to see. Companies inventories is more than ease of
delivery to customers in the business as a result. But high inventory costs will endure.(Okka 2009:657-658) Two
main purposes of inventory management in have enterprises.It‘s work both necessary and sufficient to sustain
the provision of inventory and inventory to be taken for ensuring all the stages of the inventory holding cost is
the lowest level(Okka 2009 :657-658).While investing in inventories in companies that it is important to pay
attention to two issues.
Investment in Inventories
Inventories have very important current assets in companies with a share.Operation equipment, raw
materials and supplies,work in process and finished goods inventory management are the most important items.
Inventories of companies shows diversity that it had been active in the sector depends and kinds of business.
Some sector, excessive inventory investment , when it should, and some inventory-free or low inventory keeping
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policy can be watch. Companies inventory the optimal amount of more than investing the profits in a negative
way will affect. (Ceylan ve Korkmaz 2008,318-320). Businesses must be sign in terms of inventory management
policies are determined, the firm's market share and target what is determined to be the financial terms of
inventory investments, both positive and negative aspects of evaluating the investment amount. Negative
inventory investment or business, many expenses can lead to well be forgotten.
The results of Insufficient Inventory
1.The sales fall
2.Market loss
3.Customer loss
4. Decrease in profits
5.Injury to reputation in the sector
Table 1: The results of Insufficient Inventory
Level of Raw Materials and Products in Inventory
Raw material inventory is been affected first-degree factor is future production plans for next year's
planned production degrees.Company decided to increase the amount of production for next year it will need to
increase the amount of raw material purchases ( Ceylan ve Korkmaz 2008,320).Raw inventory determines the
amount of another factor is the production seasonality specialize.Furthermore, in products shows seasonal
fluctuating , production by the amount of precautionary inventories.That well as price increases, natural factors,
delivery time, global competition and also taking into account sufficient material can be quantified. (Ceylan ve
Korkmaz 2008,320). Businesses have for sales of inventory level in a positive relationship. Production volume
occur can be reflect in the future any changes to sales figures. But Demand amount of any increase can‘t to meet
supply. Those well vogue does not exceed, in each period will be demanded of the goods or inventory in the It is
possible (Ercan 2008,305-308).
Cost of Inventory
Business occurs investment in inventories for the expenditure of large. This reason to manage inventory
with the lowest cost of total inventory cost is minimum will be required to achieve optimal inventory levels.
Cost of Keeping Inventory
Inventory held in the raw materials,work in process and finished goods to be kept and maintained due to
incurred. Stok keeping costs, storage costs, heating and lighting costs, transportation costs, wages, insurance,
taxes and outdated goods, waste and corruption costs occurs.
Inventory Supply Cost
Shipping occurs costs referred to as the inventory supply costs, the order granting inventory enterprises
reached until the last every stage of the costs from the sum. Order given the phone calls, office expenses, bank
EFT costs, discount incentives, not benefiting, warehouse transportation and other expenses ordered, the cost
creates. .(Okka 2009:660).
Cost of inventorys not Include
It is expenses of inventory keeping arise. Can not be held sales lost by the sale amount, deprived of the
profits, customers, such as loss expenses. Because of business in terms of incurred these costs in the industry and
market reputation to decrease, the brand value to fall also may result.
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Cost of Inventory
Total Cost of Inventory
Cost of Keeping Inventory
Inventory Supply Cost
Inventory quantity
Shape 1: Determining the optimum inventory level
Financial Failure in Business
Definition of Financial Failure
Financial failure is known that describing in different terms. Financial business end of the mission has
to carry out their activities. (Aydın and others 2007;444). Looking from another angle, the business can not
provide cash flow is also another dimension of financial failure. .(Wruck,1990;425). The current period as a
result, businesses can not pay debts, are faced with the problem of liquid in a technical sense(Gönenli,1994;647).
Many companies fail to define the terms we want to use. According to Altman, financial failure by the
insolvency, bankruptcy and is unable to pay on time(Altman 1983;3-6).
Causes of falling into financial failure
Businesses, technology, market, product diversification, cost structure and especially the consumer
behavior impact of their financial terms to the many problems facing. As well as business administration and
director of the inadequacy can of the company's business environment to adapt fail. Because of production
volume falls, sales declines and losses leads.
Causes of Financial Failure In Business
One of the reason those are Professional non-managerial positions, excessive and irrational borrowing,
cash flow is planned absence, insufficient liquidity, budget items necessary diligence is not shown, savings
policy is not followed, particularly cost accounting data by managers neglect, or enough of no business in the
financial failures. As our daily competition environment is considered to be high, as the company continues to
operate, improve profitability in a competitive environment must be suitable for the use of financial resources.
Another factor affecting the financial failure is financial leverage.Financial leverage, external and equity
resources of business,resource anf quantity of the substance from which mainly shows how much a financial
instrument should be used. (Erol 1999;156-157). Own resources can not be open to be allocated to enterprises,
with public debt as possible to cause any problems because the future. Companies bonds useful, financial bonds
for his use of such debt instruments or loans from banks or financial institutions to supply foreign sources are
provided. Loans to firms optimum level to a very rational, and the business growth and market competitiveness
will increase, and provide continuity in terms. But businesses will meet big problems ,if they do not use their
debts in reasonable places.For example, business uses of the loans financing the timely payment fails,
bankruptcy go through a process will enter.
Businesses within the required accounting controls is not made, cost accounting enough benefit can not
be operating in a knowledge processing and dissemination should be the system's establishment of no-budget
preparation flexibility of no and extraordinary circumstances budgets does not contain accounting information
system failure caused by financial failure are the causes.
Another dimension of the business in terms of financial failure of the timely collection and payment.
Companies hitchs can not do debit payments for the production. This result, could not obtain the necessary raw
materials for production will be reduced. Without disrupting their activities, the liquidity position of businesses
to improve profitability, cash inflows and outflows should also take into account the planning.
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Out of Business Reasons in Financial Failure
In the economy liquid cash cycle by increasing ,the country's economy development is, increases with
income, employment and especially the production. The economy revival and development of enterprises'
financial structure to strengthen contribute important. National revenue structure, the inflationary and
dezenflasyonist trends, economic policies, macro-economic indicators to the national economy that additives that
affect the financial success of companies are among the primary factors. (Dinçer 1996:53,Eren 1990:70-71). Of
these, as well as technological innovations and developments for business carries critical. New production
techniques wiil reduces, production costs, reducing the innovations do not make the business cost of any of the
relative increase their competitiveness. As we today global economy, the unit cost of profitability rather
impressed it is considered that the activities continue with the company, particularly the costs of businesses that
are reducing the minimum level.
One of the most important factor in business is technology. Technology for the business required of all
information, communications quickly and cost-effectively be provided. global economic have units to reduce
costs, consumers need to answer to, most importantly, profit and profitability to increase information for the
operating system for businesses vital. Technology processes to operate large deals in may provide, may also
reduce the risk of assets. (Dinçer 1996:51). Technological innovation, practicality and speed. ınformation
businesses operating system can be used effectively in competition with businesses, cost leadership may pass to
the front of many businesses.
Measures Towards Improving the Financial Status
Financial structure deteriorated and unable to meet payment obligations on time, to strengthen the
financial situation in enterprises for a number of measures to be taken. companies measures are grouped under
four main headings.
Strategic Measures
Future uncertainty is high today, it is impossible that companies effectively operate in the planning and
implementation. Today's businesses is quite complex with a structure is also considering, business management
strategy, the determination of its financial condition empowering nature pay attention. Economic failure to
prevent the need to be strategic measures following as can be sorted (Aydın 2007;451-453);
•Making Swot analysis and take preventive measures
•Making medium-and long-term by following the developments on the economy
•Identifing the market targets according to product groups, accordance with the management plan
Precautions to be Taken in the Field of Costs
The extension of debt maturity
The cash management business for the future if a serious obstacle facing temporary financial problems,
the firm's debt maturity, is extended by creditors to supply funds to businesses would be given the opportunity.
Because when the management contacts with enforcement, it will be receivables to collect performance fees.
Beside this thinking that it could not take a large portion of the charge, this could not claim most of charge.
Improve companies receivables net charged availability, debt extension in the financial situation for the future
promising enterprises, the creditor company in terms of rationalization would also owe the business picked
himself up to the opportunities provided, and thus happens the business liquidation or bankruptcy in the process
prevented. If necessary changes are made in management and the measures are not taken until debt maturities,
the event probability increases that management through the out without problems.(Büker,Bayar ve Sevil
2001:420)
Abandonment of claims through a section of the Magistrates
Refer law enforcement for claims to collect from the borrower company, generally a large part of the
funds could not receive. Because of management may be cash take a portion of the peace and abandon the rest
settle for if both legal lengths and deal does not need to as well as peace through education could amount
collected.
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Representatives of the firm's receivables by a committee of the Managing
Creditors can be request that the firm's management take the company's financial condition is
corrected. Another method is if the entity's management to have a say in financial support. Management that
seized the company management keeps control of management until improve financial status, if it could not
correct, it helps to entry the process of liquidation.
Capital Structure Reorganization and Strengthening of Capital
Other way to out of the failure for management which fallen to failure and unable to pay their debts,
failure to agree a way out with one of the creditors, the amount of claims for money by the business partners to
strengthen capital (Büker,Bayar ve Sevil 2001:421).
Those can take that measures for the restructuring of capital;
- Instead of debt giving the capital share
- Instead of bonds giving the stocks
- Taking new share holders
- Reduction of the nominal value of stocks in companies
- Decreasing of bond rate.
- Instead of common share giving preference stock
Table 2: Measures for the restructuring of capital
Fixed assets are sold as Long-Term Renting
Excessive investment in fixed assets if companies did it by selling the surplus, to place a long-term
leasing new assets by the method of operating cash needs can be met by renting. Due to leasing, to be a longterm financial management, accounting as expenses and tax advantages, the widely used by businesses.
Fixed assets of subsidiaries and partially or fully translated into the currency
Selling of building, machinery, land and equipment which don‘t contribute to the management to
liquidate, gives management cash conversion, as well as would have been the depreciation expense savings.
The other firms with a company in the United
A financially bleed company merger with another company and revival of the supply of a failed
business. Present sector, according to the structure, market controls, or increase profits for mergers or joint
ventures to provide management in terms of rationalization can.
Selling of Management Whole or Part
Operational cost is high subsidiaries or affiliates profit loss analysis after sell. But in long-term can be
considering the current financial failures will continue this business in whole or in part is sold, rational. Thus
failed business hand to issue a business cash flow can be ensured as well as amortization expenses decreased by
Significant savings can be achieved in the operating expenses. (Dinçer 1996:175).
Cost Reduction
An important cost area is raw matarial in management . Raw matarials purchases to save on supply
conditions improve, in use of waste and waste disposal, inventory costs, reducing some vehicle equipment
purchases instead of a bike path to be measures such as cost reduction of the privided. Cost mitigation measures
can be summarized as follows;
• If there is a demand narrow or stock oversupply, cost and expense cutting down about producing
• Skilled and talented in the areas of business activities should continue, should withdraw from the areas of poor
or weak
• Particularly if the current increases developments in exchange rates, should be cut imports, , raw material needs
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to be provided from the domestic market.
• Travel expenses should be reduced
• The budget allocated to fixed assets and new investments should be reduced
2.3.2.10. Liquidation of Companies
Despite the precautions taken, the chance to continue the company's assets is low, the company's liquidation is
not the way to go to a compulsory liquidation. Because of business is greater than the benefits to be obtained
from the liquidation will be more rational.
Measures to Boost Cash Flow
During periods of financial crisis, businesses must decrease collecting time, recovery time loan
maturities and discount for decrease selling inventory costs to get away from losses. One of the most important
cash items received orders. Advance receipt and sales or collateral requested as a short-term cash management
businesses can relax.
An Effective Financial Management and Planning
Financial management is sensitive external environment and the macro-activities of businesses.
Strategıc financial with business within the created and the company's current situation, the projected data
analysis. Now on and future environment to determine the resulting economic, demographic and social quality of
the data analysis and the environment within the company's future to determine and to estimate the financial
goals and to identify and navigate the process is carried out(Bengshir,1996:77).
The four basic criterion
(Sayılgan,2003:295);
of
financial
planning
1)Investmen fixed asset
2)Working capital
3)Combination of debt and equity
4)How company decision's will evaluate
Table 3: Decision area in financial planning
Effects of Financial Failure in Business
Enterprises' financial structure, shows differences the firm's business activities. Stops asset investments
mainly a business, it is normal that debt is more than equity capital in a mainly stop asset investment
business. if comparing the value of certaın debt and sum of long-term debt is higher, we can say for
business ―extreme owes‖. Comparing the long-term debt in excess of net debt and inventorys. If
companies long-term debt more than inventory this means that the non-cash assets in managment are
not achieved with debt they are achieved with management equity. Thus business financial failure affect
the
degree
is
reduced.
Decrease in operating profit to financial failure shows and ultimately leads to inadequate liquidity to as
the bankrupt company's failure to operate. Economic effects can be grouped into three headings
summarize.
Effects on Investment and financing
In Financially failing businesses management also seen the biggest problem, funds flow enabled. That
is result in investments late. Current period of investments can stop .Failure visit businesses in an effective
inventory policy execution, raw materials and goods across pay, is caused to spread for debt to maturities.
Business financial crisis enters its own receivables charged to, the debts to pay, for the production of essential
raw materials, supplies, and these, as well as various issues. At the end effective non-inventory policy block,
enterprise inputs and outputs of the amount planned when the realization.If production is not on the time,the
sales will fail creases, liquidity of business is getting weak as a result crisis with the effect of the company's
financial situation gets worse. Businesses is about financially unsuccessful, investments to influence the existing
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fixed assets renewal or a new entity receiving. ınvestment opportunities to be requested before the financial
situation improves, and then invest the budget should be prepared, capital or financial resources must be
provided.
Effect of Profitability
Financial failure of business in losing of sales is decreasing revenue and the cost is getting more, the
company's profitability is decreasing.At collectting troubles, is getting low particularly the receivables turnover.
It will be weak its pay. Because of cash cycle is insufficient, the company can not avaluate alternative
investment opportunities and failed emerged a small but are deprived of lucrative opportunities.
Inventories and Sales Effectiveness
Inventory turnover, in other words the cost of goods sold is lower than the average ratio of inventory
desired sales means the amount could not be reached. Financially troubled the businesses, the sales of a
sufficient level, not in a production line to slow down production of the amount of reduction and long-term debt
payments difficulties caused. This is well as businesses, the financial crisis in the asset and liquidity management
difficulty is the determined sales policy not access because of their strategic goals to achieve are also affected.
The Effects of Financial Failure in Business Inventory Management
Inventory Turnover and Productivity Effect
Turnover rate is shown the company's sales rate to the average amount of inventory that how many
times to meet. The low inventory turnover in enterprises, means that the desired amount of sales can not be
reached. Inventory turnover ratio is lower one of the reasons, the business sold to inadequate is the other one too
much inventory. Financial failure falls in business ,the most common problem is not sales of the desired level in
the other receivables charged face in the difficulties are. Financially troubled the businesses, the sales of a
sufficient level, not in a production line to slow down production of the amount of reduction and long-term debt
payments difficulties caused. The sells insufficient, the collection of receivables be key delays, business liquidity
and purchasing power.This is well as businesses, financial crisis manage their assets and liquidity in times of
difficulty, because the achievement of designated sales policy and therefore unable to reach their strategic goals
are also affected.
Sales Effectiveness
Today's business in the most common questions one of the companies' strategic plans, the targeted sales
figures. Companies internal and external factors due to the desired sales figures reach the difficulty the company
cash problems.Companies the most important liquid pen is sale revenues.Because of sales desired level of the
lack of goods sold cost will increase inventory turnover and sales profitability.inventory management required in
the raw materials and finished goods reach the level fail business sales reduce the road.Inventory obtained time
effectively not be used as both the sales decline and the reputation of the injury caused. That in a situation
inventories to be different can make of the growing inventory of applications and campaigns. Unlike cash
management businesses that getting more and more inventory invesment will be paralyzed and market share
have been determined to block and eventually entered a path that goes up to the bankruptcy will cause.
Liquidity Impact on Business
Businesses at the establishment stage by partners of capital on the basis of the liquid assets first started
operating the business of the cash power. In hand of funds, investment products or commercial goods inventory
as to be converted, realized sales policy, together with their re-liquid assets into a spin this cycle of business
activity to end until.Liquidity asset management firms manage the difficulty that the biggest problems. Cash
management and effective planning is not if businesses purchase of raw materials from the tax payment until the
costs and spending cash deficiency faced with the problem caused. Liquidity insufficient purchasing advance
sale discount to benefit will stop time can not be payments to interest costs caused. This well as taxes and
payments will be delayed by the state penal sanctions exposed because of inventory management-enabled not
business's cash assets are sufficient to prevent. Indirect to as operating cash management activity on corruption
to-day spending can not become ,as a result of the liquidation or bankruptcy and go into a process that will lead
to.
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Conclusion
Connect to inventory without too much money, short-term debt funding can be provided to increase the
inventory turnover rate. Financially failing businesses, the inventory turnover rate is low, sales are at a desired
level or not will result, thus operating liquidity shortage.Economic failure as a result of businesses went
bankrupt, and most employees become unemployed and even creditors, the companies that victims and their cash
flows regulated can not, and as a result from this process adversely affected Financial crisis in the business, cash
flow chart of the arrangements, their debts to restructure, if possible, debt with stocks for replacements, inert
tangible assets to sell, the costs of reducing possible, as well as business management and organizational scheme
to modify,the financial crisis at least with loss through will ensure . Although all these measures, if the financial
failure is still running, the business financially restructuring, downsizing strategy, the implementation of the
rational, non-affiliates or subsidiaries to sell. financial failed businesses restructuring as a result of the current
situation for the future bright appear unless the company's liquidation to be investors, both creditors is rational
for enterprises with the least harm will withdraw from the market.
References
Altman Edward,Corporate Financial Distress: A Complete Guide to Predicting,Avıiding and Dealing with Bankruptcy,Jhn
Wiley and Jons, Newyork.1983
Aydın Nurhan,BASAR Mahmut,COġKUN Metin, Financial Management ,Genç Copy Center,EskiĢehir,2007.
Bengshir Türksel, Information Technology and Organizational Change , TODAĠE Publishing.Ankara,1996.
Büker S.,D.Bayar,G.Sevil, Financial Management ,Anadolu University Publishing, EskiĢehir ,2001.
Ceylan Ali ,Korkmaz Turhan,Financial Management in Business,Ekin Bookstore,Bursa,2008.
Dinçer Ömer, Strategic Management and Business Policy ,Beta Publishing,3.print,Ġstanbul,1996.
Ercan Metin Kamil,Financial Management Based of Value, Gazi Bookstore,Ankara 2008.
Eren Erol, Strategic Planning and Management in Business ,Faculty of Business Administration Publishing,
no.234,3.Print,Ġstanbul,1990.
Erol Cengiz, Financial Management in Business ,Ġmge Bookstore,Ankara,1999.
Gönenli Atilla, Financial Management in Business ,Ġstanbul,1994.
Okka Osman, Analytical Financial Management ,Nobel Publishing,Ankara,2009.
Sayılgan Güven,Business Finance,Turhan Bookstore,Ankara,2003.
Wruck,Karen Hopper.Financial Distress: Reorganization and Organization Efficency,Journal of Financial
Vol:27(2),October.(s:419-445),1990
238
Economics,
�
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165
Title
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The Effects of Financial Failure in Business Inventory Management
Author
Author
CİVAN, Mehmet
DAYI, Faruk
Abstract
A summary of the resource.
Global competition increases, inventory management businesses on the importance increased. Goods and services to sell in the global market, the unit costs low, the production efficiency is need to higher..Stok management, raw material supply whether manufactured and offered to customers are far, production and distribution activities is fundamental. The amount of inventory the company's total assets 40% to 60% in the thought, the investment in a significant portion of the inventory allocated to the will see. Especially,in trade businesses inventory, is majority of the balance sheet active.In the industry businesses the fixed assets ,investment is well ossified in inventory that will see. That in a state enterprise liquidity is insufficient and receivables collected in both high-cost inventories disposal are challenges. Daily operations to meet cash asset management could not, pay their debts to be forced, commercial reputation damage to the liquidation or even bankruptcy process go through a process to enter will result.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
HB Economic Theory
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https://omeka.ibu.edu.ba/files/original/762b428566216d86ad45db46900cd2a3.pdf
ce731d1dd185c1fac652002515d576aa
PDF Text
Text
2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
Differences Between the International Accounting Standards and the
Theoretical Structure of Accounting in Turkey
Mehmet CĠVAN
Faculty of Business Administration, Gaziantep University
Turkey
civan@gantep.edu.tr
Ekrem KARA
Faculty of Business Administration, Gaziantep University
Turkey
ekara@gantep.edu.tr
Abstract:Accounting system provides non-misleading and controllable information on a
company‘s financial structure and consequences of its activities. In this context, the
theroetical structure of accounting is important. Accounting practices are in a constantly
changing and developing environment. There are major differences between accounting
practices and its theory. There are a number of institutions and organizations in Turkey
that affects the theroetical structure of accounting. After the adoption of new Turkish
Commerce Law, this multi-headed structure will be eliminated. According to the draft of
new Turkish Commerce Law, Turkey Accounting Standards Board (TASB) will be
responsible from the accounting regulations in Turkey. As a matter of fact, this
institution has been issuing the International Accounting Standards in Turkey since its
establishment in 2005. Until now, the TASB has issued 29 standards for the publicly
traded companies and it is also preparing International Accounting Standards for the
SMEs in Turkey. This study examines the theoretical structure of accounting in Turkey
and its differences from the International Accounting Standards.
1.1. Theoretical Structure Of Accounting
Theoretical structure of accounting aims at establishing a structure of theories and implementations which
will result in harmonization of the efforts of the persons from the accounting profession, and a common set of
standards and procedures called generally-accepted accounting principles, and which will function as general
guidelines.
Tax Procedural Law (TPL) enacted with the tax reform during the 1950s constituted the basis of the
theoretical structure of accounting in Turkey and today, it maintains its directive effect. Turkish Code of Commerce
(TCC), Uniform Accounting System of the Commission of Reformation of State Economic Enterprises, Banking
Law and Banks Uniform Chart of Accounts, Communiqués of the Capital Markets Board, Accounting System
General Communiqués on Implementation of the Ministry of Finance, Uniform Chart of Accounts (UCA) that follow
this regulation, Turkish Accounting Standards (TAS) formerly published by the Turkish Accounting and Auditing
Standards Board and now, by the Turkish Accounting Standards Board are the primary written legal norms that
direct accounting implementations in Turkey (Cemalcılar and Önce, 1999, 10).
1.2. Framework Of The Theoretıcal Structure Of Accountıng
In the previous part, the regulations that affect theoretical structure of accounting in Turkey have been
mentioned. In this part, framework of the theoretical structure of accounting will be dealt.
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OBJECTIVES
* Providing information on investment and
credits
* Estimating cash flows
* Providing information on assets and resources
of the enterprise
QUALIFICATIONS OF ACCOUNTING INFORMATION
A. Primary Feature
1. Relevancy
a. estimated value
b. feedback value
c. timeliness
2. Safety
a. provability of accuracy
b. loyalty in representation
COMPONENTS OF THE FINANCIAL STATEMENTS
c. impartiality
Financial Status
Changes that
affect financial result
B. Secondary
Feature
Assets
Returns
1. Comparableness
Debts
Expenditures
2.consistence
Equities
Assumptions
Non-operating
BASIC
CONCEPTSprofit/loss
OF ACCOUNTING
General Features Constraints
PRINCIPLES ON IMPLEMENTATION
ACCOUNTING STANDARDS
ACCOUNTING POLICIES
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Table 1: Hierarchy of the Elements that Comprise Framework of the Theoretical Structure of Financial Accounting
(Cemalcılar and Önce, 1999, 26)
1.2.1. Objectives of Financial Accounting
The accounting function can be defined as determining, registering, summarizing and reporting financial
information. The accounting information, which is the most important source of information in a company, also
plays a significant role in the stages during which administrative decisions are made. (Cemalcılar and Önce, 1999,
27)
The objectives of accounting are comprised of 4 elements, which are namely determining, registering,
summarizing and reporting financial information (www.akampus.com).
1.2.1.1. Determining Financial Information
The accounting process begins with determining which financial information will be registered. This is
called determination of the information. As a general rule, it determines and registers financial transactions of
accounting and results of financial activities. However, their controllable proofs should exist in order for these
financial transactions to be kept under accounting records. This is called the rule of cautiousness, which is also one
of the important rules in ‗Generally-Accepted Accounting Rules‘ (Cemalcılar and Önce, 1999, 28).
1.2.1.2. Registering Financial Information
Accounting information is registered into the accounts. These accounts enable classification of financial
data. All accounts of a company are registered in a daybook and a general ledger, which are the official books of
companies (Civan and Kara, 2009, 53).
1.2.1.3. Summarizing Financial Information
The data processed during the accounting process should answer different requirements of different users. In
other words, it should be possible to classify and summarize this information in a way to meet the data requirements
of various decision-making models (Civan, 2010, 3).
1.2.1.4. Reporting Financial Information
Accounting reports aim to meet requirements of the persons who use accounting information. Thus, these
reports should be user-specific. In different reports, different reporting methods can be followed. There should be full
compliance with the tax laws in the reports prepared for the state and tax administrations. In the reports to be
provided for the public or third persons, compliance with the Generally-Accepted Accounting Rules is sought
(Akdoğan and Tenker, 2007, 3).
1.2.2. Qualifications of Accounting Information
Timely and accurate information is required for a successful management. Appropriate decisions can only
be made by means of accurate, timely and fast information (Hansen and Mowen, 1992: 4).
It is common knowledge that the enterprises influence each other, thus the economic situation of the society,
as well as their economic situations through the decisions that individuals and states make (Kepekçi, 1998: 37).
Related parties need to have accurate, sound, significant, related and timely information on the enterprises in
order to protect their benefits because the economic decisions that the information-users will make in accordance
with their aims depend on the accounting information (Bodnar, and Hopwood, 1998: 55).
1.2.3. Scope and Components of Financial Statements
The financial statements prepared by the accounting department are divided into two; namely, main
financial statements and supplementary financial statements (Çabuk and Lazol, 2000: 7).
Furthermore, the reports can be divided into general and special-purpose reports. Main financial statements
are common as general purpose, and arranged for all users in a standard way. Balance sheets and income statements
can be given as an example. Special-purpose reports are arranged especially for administrations or other private
persons. Budgets, performance reports, cost reports etc. can be given as an example of this kind of reports (Yılancı,
1992: 15).
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1.2.4. Principles on Implementation
Basic concepts of accounting that constitutes the theoretical basis of the accounting implementations are
general decision-making rules. Accountants use the principles on implementation, in other words, detailed principles
in order to implement the basic concepts.
1.2.5. Accounting Standards
Accounting standards determine the method of accounting studies and are published by various national and
international organizations. The accounting principles are generally implemented through the accounting standards,
and take determination of an accounting policy as a basis.
In our country, the accounting standards are published by the ‗Turkish Accounting Standards Board‘
(TASB).
The Board adopts the following principles in determining national accounting standards:
1-The accounting standards determined should be compatible with international accounting standards.
2-The Turkish economy, structure and requirements of the enterprises should be considered.
In Turkey, publicly-held enterprises prepare reports according to the Turkish Accounting Standards. For
non-public enterprises, on the other hand, international accounting standards continue for the SMEs.
1.2.6 .Accounting Policies
The accounting policies are a complement of standards, opinions, comments, rules and regulations accepted
by the enterprise among the options in order to arrange and submit financial statements. For instance, they can prefer
the required method used in the calculation of amortization (Özulucan, 2003, 15).
1.3. Theoretical Structure Of Accounting In Turkey And Differences With International Financial Reporting
Standards (Ifrs)
Although international accounting standards and the uniform chart of accounts are based on the same
principles, different approaches are brought to the subjects of accounting policies that need to be implemented. The
most significant reason of these different approaches is that the uniform chart of accounts is affected by especially
tax legislation, and as a fundamental objective; that various regulations are made on tax-related area rather than
providing sound, trustworthy, transparent and comprehensible financial statements. The important differences
between the international accounting standards that takes substance over form and accrual basis as the basic
perspective, and tax legislation, and uniform chart of accounts that takes form over substance and collection as the
basic perspective are summarized as below.
Communiqués of the Capital Markets Board that direct accounting implementations in our country have
accelerated the efforts on harmonization with the international accounting standards. According to the Communiqué
No. 25, which is the latest regulation and issued by the Capital Markets Boards, incomes and expenditures can be
presented in a different way in order to provide information necessary to make an economic decision and suitable for
the need. Incomes and expenditures comprised of ordinary activities and other incomes and expenditures are
demonstrated separately. This distinction is made on the grounds that the information on the source of an item is
suitable for the need with the aim of making an evaluation about cash and the cash equivalents that the enterprise
may form in the future http://www.econturk.org/Turkiyeekonomisi/ferTMS10.doc).
In Turkey, the information used in reporting is not exactly compatible with the international accounting
standards. Again, there are differences between Turkey and the IFRS in reporting borrowing costs. It is possible to
include interest expenses in asset costs in Turkey, and this implementation is common. According to the IFRS,
financing expense specifies the interest costs borne by any enterprise with regard to loan capitals. What the interest
costs related to the loan capitals are is referred in the same paragraph. These are; discount expenses occurring during
the issue of bills, and repayment of premiums, repayment of related expenses borne as a result of debt agreements,
and exchange differences occurring with regard to loan capitals to the extent that they can be considered as interest
expenses (Akdoğan, 2003, 25-40).
There are some minor distinctions in accounting exchange differences of fixed assets after active registered.
According to the Capital Markets Board and the Turkish Accounting Standard 14, except for the basic method, the
exchange differences calculated for stocks and fixed assets until the activation date are added to the cost of the
related asset. According to the Capital Markets Board, adding the exchange differences occurring after the activation
date to the cost in fixed assets or registering them as a period cost is allowed while they are accepted as a period cost
751
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
in the stocks. On the other hand, according to the International Accounting Standards, exchange differences are
considered as the expenditures of the upcoming periods of the fixed assets in a systematic way throughout their
lifetime. In the International Financial Reporting Standard called ‗Stocks‘ No. 2, it is expressed that the exchange
differences occurring after the activation of non-qualifying stocks and resulting from exchange transactions related to
the mentioned assets, and borrowing costs borne by the used credits cannot be activated
(www.platformiletisim.com/malimusavir/yazarde.asp?).
Another distinction is related to accounting financial leasing operations. They continue to show the assets
given for leasing in their own assets as fixed assets and allocate amortization for them. This situation distorts the
structure of balance sheet. In fact, the assets given for leasing should not be included in fixed assets, and
amortization should not be allocated for them. The companies that obtain assets by means of leasing should show
these assets in their own assets and allocate amortization for them (Akdoğan, 2003, 25-40).
Another distinction is that the financial reporting in the companies that carry out widespread construction
and contracting works for many years differs from the implementations in the International Accounting Standards.
The period results of incomes and expenditures are received in the year when provisional acceptance takes place in
Turkey. In fact, according to the International Financial Accounting Standards, incomes and expenditures should be
calculated by the completion percentage for each year, not in the year when the provisional acceptance takes place.
Afterwards, incomes and expenditures should be reflected into the periods.
Furthermore, realistic values, rather than historical costs, should be taken as a basis while evaluating some
items. Realistic evaluation principles, instead of historical costing, should be considered.
In accordance with the principle of cautiousness in the International Accounting Standards, it is necessary to
allow to making provision when a decrease in the value of any asset is noted/estimated (doubtful trade receivables,
decline in value of inventory etc.), and to register it as an expense. In fact, for allowing to making such a provision
and accepting it as an expense, the tax procedural law has brought along such obligations like court decisions etc.
Another distinction between theoretical structure of accounting implemented in Turkey and the International
Financial Reporting System is the delay interests occurring in forward sales. In fact, these are interest income not
sale income. As a result of this, gross margin seems too much in income statement.
Although there is a parallelism between the international accounting standards and the standards published
in Turkey on arranging consolidated financial statements, there exist discrepancies in definitions, consolidation
preparation stage, reporting special assessment, in conditions regarding exclusion of the determination of the special
assessment
from
the
scope
of
consolidation
during
repayment
(
http://www.sosbil.gazi.edu.tr/edergi/makale.php?Makale=8).
Another distinction is related to where the sale of fixed assets and shares will be shown in the income
statement. The international accounting standards state that these profits should be shown in the ordinary income
group. However, they are shown in the extraordinary income group in the applications in Turkey.
www.econturk.org/Turkiyeekonomisi/ferTMS10.doc
As for the accounting of the shares, pertaining to the authority granted by the article 175 and repeating
article 257 of the Tax Procedural Law by the Ministry of Finance, the General Communiqué 3 on Implementation of
the Accounting System Serial No. 1 which was enacted to be effective as of 1.1.1994 covers all real and legal
persons that keep accounts on the basis of balance sheet throughout the country. In this regulation also called as
Uniform Accounting System in the implementation, it is defined that as criteria for participation, vested right of
voting or right to participation in the administration, rather than the share, should be taken as a basis, and that the
vested right of voting or right to participation in the management should be at least %10, regardless of the share, in
order to mention a relationship of participation in the joint ventures participated. In the abovementioned regulation,
principles and standards on the evaluation were not introduced; TPL provisions were referred on the matter of
evaluation. Thus, the participations will be valued over ―purchase price‖ as is the case with other securities. Provided
that there is a decrease in value of equities by %10 or more than this rate, it is allowed to make provision in
accordance with ―the principle of cautiousness‖. On the other hand, increases in value of securities cannot be
associated with the period profit/loss as they are unrealized increases. Only the profit or loss realized when they are
sold is taken into account.
Conclusion
In the world, International Accounting Standards are adopted in financial reporting. The information
presented in financial reporting will be determined according to these principles for all countries. A unique
implementation will be adopted in the standards. The European Commission has made it necessary to prepare
consolidated financial statements in compliance with the International Accounting Standards as of 1.1.2005. In this
752
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
sense, Turkey aligns its national accounting standards published since 2005 with the international accounting
standards. Nevertheless, there are some differences within the theoretical structure of accounting. In titles, these
differences are as below;
- In accounting policies,
- In showing incomes and expenditures comprised of ordinary activities, and other incomes and
expenditures separately,
- In reporting borrowing costs,
- In accounting exchange differences of fixed assets after active registered,
- In amortization rates applied,
- In accounting leasing transactions,
- In financial reporting in the companies that carry out widespread construction and contracting works for
years,
- In delay interests occurring in forward sales,
- In arranging consolidated financial statements,
- In where the sale of fixed assets and shares will be shown in income statement.
References
Akdoğan Nalan. (2003). ―Finansal Raporlama Uygulamalarında Uluslar arası Standartlara GeçiĢ‖. Ġstanbul. TÜSĠAD
Akdoğan Nalan, Nejat Tenker, (2007), ―Finansal Tablolar ve Mali Analiz Teknikleri‖, Ankara, Gazi Kitapevi
Bodnar, George and William, Hopwood. (1998). ―Accounting Information Sytems‖. New Jersey. Prentice Hall.
Cemalcılar Özgül ve Saime Önce. 1999. ―Muhasebenin Kuramsal Yapısı‖. EskiĢehir. Anadolu Üniversitesi
Civan Mehmet, (2010), ―Dönem Sonu Muhasebe ĠĢlemleri‖, Ankara, Siyasal Kitapevi
Civan Mehmet, Ekrem KARA, Vedat Bal,(2009) ―Luca Uygulamalı Bilgisayarlı Muhasebe‖ Ankara, Tesmer,
Çabuk, Adem. Ġbrahim Lazol. (2000). Mali Tablolar Analizi. Bursa: VipaĢ A.ġ.
Hansen, Don R. Maryanne M.Mowen. (1992). ―Management Accounting‖. USA.: South- Western Publishing.
Kepekçi, Celal. (1998). ―Bağımsız Denetim‖. 83.Baskı) Ankara: Siyasal Kitabevi.
Özulucan Abitter, (2003) ―Dönem Sonu ĠĢlemleri ve Muhasebe Uygulamalar‖, Ġstanbul, Türkmen Kitapevi
Yılancı, Münevver. (1992). ―Muhasebe Organizasyonu‖. Kütahya: Kütahya Üniversitesi Ġktisadi ve Ġdari Bilimler
Fakültesi Yayınları. (www.akampus.com).
http://www.econturk.org/Turkiyeekonomisi/ferTMS10.doc
www.platformiletisim.com/malimusavir/yazarde.asp?idyazi=70
www.econturk.org/Turkiyeekonomisi/ferTMS10.doc
www.econturk.org/Turkiyeekonomisi/ferTMS10
753
�
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227
Title
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Differences Between the International Accounting Standards and the Theoretical Structure of Accounting in Turkey
Author
Author
CİVAN, Mehmet
KARA, Ekrem
Abstract
A summary of the resource.
Accounting system provides non-misleading and controllable information on a company‘s financial structure and consequences of its activities. In this context, the theroetical structure of accounting is important. Accounting practices are in a constantly changing and developing environment. There are major differences between accounting practices and its theory. There are a number of institutions and organizations in Turkey that affects the theroetical structure of accounting. After the adoption of new Turkish Commerce Law, this multi-headed structure will be eliminated. According to the draft of new Turkish Commerce Law, Turkey Accounting Standards Board (TASB) will be responsible from the accounting regulations in Turkey. As a matter of fact, this institution has been issuing the International Accounting Standards in Turkey since its establishment in 2005. Until now, the TASB has issued 29 standards for the publicly traded companies and it is also preparing International Accounting Standards for the SMEs in Turkey. This study examines the theoretical structure of accounting in Turkey and its differences from the International Accounting Standards.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
HB Economic Theory
-
https://omeka.ibu.edu.ba/files/original/6e66c909187716382a85f8ea02bfaa54.pdf
925bb23c85ea665e2424fa2fb8988427
PDF Text
Text
2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
International Financial Reporting Standards for Smes and
The Applicatıon Process In Turkey
Mehmet CĠVAN
Assist. Prof., The University of Gaziantep
Faculty of Economics and Administrative Sciences
Business Administration
civan@gantep.edu.tr
Mehmet KÖRPĠ
Lecturer , The University of Gaziantep
Naci Topcuoglu Vocational School of Higher Education
korpi@gantep.edu.tr
Burcu BUYURAN
Vocational School Part Time Lecturer
The University of Gaziantep
Naci Topcuoglu Vocational School of Higher Education
bbuyuran@hotmail.com
Abstract: Today, 95% of the world and in our country's economic system occurs from
the Small and Medium-Large Enterprises (SMEs) constitute. Only the European Union,
more than 25,000,000 and in our country 1.000.000 companies is estimated in the SME
status. As shown the SMEs get a large share of sector ,the existence of their special
structure, has become inevitable. One of these special structure, is financial reporting.
Increasingly widespread use of International Financial Reporting Standards,the issue of
how to implement those standards to SMEs, has been brought up. And for this problem in
2009 "SMEs for IFRS''was published. by IFRS.
In this context, the basic aim of our study is to investigate and see the implemention
proses of ―IFRS for SMEs‖ which resolve the differences of national accounting systems
that applied in various countries of the world and will enable to comparison of financial
reports and to see how affects and what would bring to Turkey‘s economic system.
Keywords: Small and Medium-Large Enterprises (SME), International Financial
Reporting Standards (IFRS), Accounting, Financial Reports
1. Introductıon
After the product of the five-year study, International Accounting Standards Board ("IASB") was
released on 9 July 2009 ―International Financial Reporting Standards‖ in line with the SME accounting
standards ("IFRS for SME's") for Small and Medium-Sized Enterprises ("SME") that estimated
approximately 95% of all businesses on the world. In the development of Accounting standards on SMEs;
SME Commission be formed from forty person, working like counselling to establish the contents of
standards and in order to measure of the SME-oriented approach to the final draft ,the draft was published in
five different languages. More than fifty meetings arranged to final draft, pilot applications done more than a
hundred enterprises in more than twenty different countries and after be finalized set of draft standarts , the
standarts be published
The differences between applying national accounting systems in various countries of the world,
makes hard to comparability of financial statements and makes difficult for investors the identification of
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
investment opportunities in different regions of the world , also slowing foreign capital inflows to
emerging economies and investors in the decision making process increases the investment risk.
Accounting standards for SMEs is expected to provide, consistently applied globally to a
common financial language requirements, that become almost indispensable for the mobility of capital
more easily and quickly in with each passing day more integrated capital markets
Accounting standards for SMEs, was prepared more simpler, more easily performed and designed with
an understandable language than IFRS and according to the needs of enterprises in various parts of the
world .
SME accounting standards published an independent set of accounting standards from IFRS
and countries which IFRS doesn‘t applied will be able to use based their initiatives. Which businesses
will be covered by these standards are left to the discretion of the relevant countries.
In order to put an end to implement the multi-headed, in Turkey's accounting and financial
reporting system ; Turkey Accounting Standards Board (TASB) that have administrative and financial
autonomy and public entities has been established. for to create and publish accounting standards
TASB have adopted IFRS in order to ensure compliance with European Union legislation and to
close the world applications. with this decision TASB) was signed between the copyright and license
agreement, by the International Accounting Standards Foundation (IASCF) and has been decided to
make an official translation by TASB. As a result of this study Turkey Accounting Standards (TMS) was
published in the Official Gazette. Corrections and additions will be made to IFRS are expected to apply
by TASB for to continue to ensure full compliance of IFRS and TFRS with the order.
2. SMEs (Small and Medium-sized enterprises) Definition and Criteria
Financial Reporting Standards published for SMEs is defined SMEs as ―SMEs are Bussinesses
without Public accountability obligations and publish general purpose financial statements for external
users‖.
External users stated in definition are;
Business owners that are not in business management
Lenders or potential lenders of business
Ġnformation users such as Credit rating agencies
Standard, was sort obligation to account to the public situations like the following:
a.Company's debt and equity instruments (stocks), domestic or foreign capital market or over the
counter market, including local and regional markets the public in an open market transactions, or that
such a market process to see these instruments exported in the process of be be.
b.Assets, with the title custodian be maintained on behalf of a large mass counterparts. (Banks,
Investment Banks, mutual funds, insurance companies, pension companies, pension funds, brokerage
companies, factoring companies, leasing companies and other financial institutions, etc.)
Small and medium-sized enterprises (SME), defined in terms of some criteria are companies
that do not exceed a certain size. SME criteria vary between countries. The European Union and Turkey,
the Ministry of Industry and Commerce has identified the SME criteria are as follows:
Criteria
Number of Employees
Amount of sales; (Euro)
Total assets (Euro)
Micro-Scale
<10
<2.000.000
<2.000.000
Small-Scale
<50
<10.000.000
<10.000.000
Medium- Scale
<250
<50.000.000
<43.000.000
Table 1: Valid from 2005, according to EU criteria for SMEs
Criteria
Number of Employees
Amount of sales; (Euro)
Total assets (Euro)
Micro-Scale
<10
<1.000.000
<1.000.000
Small-Scale
<50
<5.000.000
<5.000.000
Medium- Scale
<250
<25.000.000
<25.000.000
Table 2: Criteria for SMEs according to the Ministry of Industry and Trade
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
3. International Financial Reporting Standards For SMEs
Financial reporting standard for SMEs, are intended to be used for small and medium-sized
enterprises (SMEs) is simplified than the full set of accounting standards
Standard consists of a total thirty-five chapters. This sections is also included the section of the
definition of SMEs and two sections describe concepts and general principles. Ġn this state of standarts it
is not true to perceived standards as a miniature set of IFRS. Because to be enhanced that with the
standards there are found special solutions apart from IFRS.
Ġt is considered by everyone that Special standards for SMEs will be developed to meet the needs
of the individual nature of SMEs. In other words, developed a "special standard" must be applied without
no dependents set of IFRS. The major criticism of the earlier draft version of the standard is
implementation alone regardless of the standard set of IFRS can not be possible. Accordingly, the
standard version of the first set of IFRS for application to be able to fully implement, while the new
version with a very large extent, this situation has been eliminated.
Another major criticism towards IFRS is changing of the standards too often. The changing of
Standards very often, makes the implementation of standards for practitioners difficult. While the
publication of these standards, updates will be made as possible intermittent (unless absolutely necessary
to make updates every three years) have been described in the standard will make it more stable. With the
standard of such a policy be presented, especially for SMEs, should be regarded as a positive situation.
4. The Contents of Financial Reporting Standards for SMEs
Accounting standards for SME to be prepared by IASB, consisted of three parts.
In Section One, Chapter 35 (standard) and a dictionary
In the Second Section; Implementation Guide (sample financial statements and footnote
information to be announced)
In the Third Section, the descriptions of the standards check list is explained.
Figure 1. "IFRS for SMEs" according to the latest draft of partitioning
94
�In the full set, Standards are released with a separate standards codes, Ġn SME financial reporting
standards as published in the Code section. Each chapter covers one or several standard according to the
situation. SME standard consists of 35 sections.
Section
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Section Name
Small and Medium Sized Entities
Concepts And Pervasıve Prıncıples
Fınancıal Statement Presentatıon
Statement Of Fınancıal Posıtıon
Statement Of Comprehensıve Income And
Income Statement
Statement Of Changes In Equıty And
Statement Of Income And Retaıned
Earnıngs
Statement Of Cash Flows
Notes To The Fınancıal Statements
Consolıdated And Separate Fınancıal
Statements
Accountıng Polıcıes, Estımates And Errors
Basıc Fınancıal Instruments
Other Fınancıal Instruments Issues
Inventorıes
Investments In Assocıates
Investments In Joınt Ventures
Investment Property
Property, Plant And Equıpment
Section
No
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
Section Name
Intangıble Assets Other Than
Goodwıll
Busıness
Combınatıons
And
Goodwıll
Leases
Provısıons And Contıngencıes
Lıabılıtıes And Equıty
Revenue
Government Grants
Borrowıng Costs
Share-Based Payment
Impaırment Of Assets
Employee Benefıts
Income Tax
Foreıgn Currency Translatıon
Hyperınflatıon
Events After The End Of The
Reportıng Perıod
Related Party Dısclosures
Specıalısed Actıvıtıes
Transıtıon To The IFRS For Smes
Table 3: Department of IFRS for SMEs
5. " IFRS For SMEs " of the United States, European Union and in Turkey Forecast
Developed standards, largely to meet the needs of SMEs are expected.Because of no negative opinion
to draft text makes strengthening the argument. Primarily for the implementation of standards by SMEs of
the country's internal legal system of standards is required to be transferred.
USA Status
In the United States there is no Standard or standard set developed for SMEs, Besides this Only the
Companies following to SEC(U.S. Securities and Exchange Board ) disclosure requirement of their financial
statements (Ġn EU ,all capital companies have to publish financial statements )shows the transposition of
standards to domestic law is as not easy as estimated .
From the perspective of the IASB in the U.S. in dealing with the process currently is uncertain how it
will operate.Ġn the process of convergence with USA (Process of USA counterpart is FASB) carried out no
plan to develop accounting standards for SMEs for now
5.2.The European Union Status
In full integration prosess to EU hhe most important public Works of financial integration practises
is due to accounting practises become compatible with EU countries and international scales.For this purpose
important Works is done within the EU. EU has a working mechanism to achieve the full integration of
accounting practises .
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
While IFRS implementation issues, the EU opened in front of the application, in what direction will
be decided for SMEs become obvious in future times .
Need to accept that find applications of Ġnternational financial standards in EU have a significiant
effects for to be used standards widely in the world. The most tangible results of this implementation has
been seen in editing of Implementation of IFRS in listed companies.
Union to apply IFRS in the EU to enforce regulations in many counties, including Turkey, in many
countries on the implementation of IFRS set of regulations to be made easier.
In countries subject to regulations were released for companies that application of IFRS obligation is
not set in the EU. Ġn EU countries, it is essential that the 4 and 7 regulations implementing guidelines for
companies outside of this arrangement. IASB has published IFRS for SMEs is currently applying for EU
countries are not mentioned.Ġn other words, unless the EU adopted the Standard ,this practice will not be
mentioned in developed countries within the EU.Unless accepted standards of practice for SMEs in the EU 4.
and 7. guidelines will continue to apply.
5.3.Situation in Turkey
The Dynamics of IFRS practice in Turkey is Turkey‘s EU accession process.To some extent as a
result of this process but largely to the initiative of the authorities concerned since 2005 International
Financial Reporting Standards in Turkey with full compliance with IFRS has found applications. Viewed
from this angle, the Companies in Turkey, in terms of public AccountAbility IFRS is not a problem for the
Implementation of the set. Real challenge for Turkey is how to implement of accounting standards in
companies that not obliged to give public accounts (mainly SMEs). Ġt is obvious that The TCC proposal
being discussed in Parliament (Bill) and recorded the important progress in this process. .In other words
implementing the provisions of the draft IFRS for SMEs that are missing parts will be completed.
Bill 88 / (1). The article "real persons and corporations to trade books, the amount while both the
individual and consolidated financial statements do editing, just to follow and implement Turkey Accounting
Standards Board published by Turkey, Accounting Standards , the conceptual framework in accounting
principles and their integral part and the comments of them‖ provision, introduced.
Figure 2: Board of Education in Turkey according to the draft Framework for the Implementation of IFRS
According to the provisions of the bill, companies will have to apply TFRS keep their accounting
records until financial reporting .Ġt is clear that the big companies would not be issues for implementation of
this provision . However ,there could be problems in the SME size companies is foreseen.
For the same article 3. of in the paragraph “Turkey Accounting standards boards be placed in special
and exceptional standards for businesses and industries in different criteria as state regulations allowed in
different ways by International Financial Reporting Standards ; those who implement them, status in
question, are explained in footnotes of financial statements” provision is included.
The draft of these regulations is defined an "exception" for implementation in SMEs TFRS set.This
provision is based on for different scale enterprises in case of implementation of specific standards to allow
development of specific standards by TASB. Naturally these standarts will have to be developed in full
compliance with IFRS. In other words this regulations is reference to developed by the IASB standard of
IFRS for SMEs .Because in this case this matter was clearly expressed. IFRS for SMEs developed in Turkey
96
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
for the implementation of SME companies, TASB Turkey by the International Financial Reporting Standards
as required to publish. This circumstance is a necessary condition for perspective to TASB activities..
TFRS set and how to implement TFRS standards for SMEs in companies is organized in Turkish
Commercial Code and law on Application of the 13/2 (a). Accordingly this article, “Turkey Accounting
Standards board may publish Turkey Accounting Standards in line with IFRS for small sized capital
companies and all sizes of companies,individual companies,real person transactions or industries.This case
referred companies and businesses are applied mentioned specific standards.However,companies and
businesses can apply rather than spesific standards withTurkey Accounting Standards fully compatible with
IFRS” rule will be implemened by companies
Individual /
Consolidated
Financial
Statements
Individual /
Consolidated
Financial
Statements
Large Capital Stock
Companies
TFRS
SMEs
TFRS for SMEs
Individual
Companies
TFRS for SMEs
Real Persons
TFRS for SMEs
Figure 3: Scope of Application TFRS According to the draft TCC
Accordingly, the public accountability of corporations (publicly traded companies and banks and
insurance companies) naturally will be applied TFRS set , and the Small-scale capital firms and individual
companies with real people traders will be applied TFRS standards for SMEs. According to the same
provision also non SME sized (Large) capital firms will be applied TFRS set. Such an arrangement be made
for Small- Scale companies as the reasons set forth in the relevant articles of the relevant international
organization (the IASB) and prepared by the standard issues of SMEs in Turkish law, the legal infrastructure
is to be reflected.
How many companies will be involved in the regulation of the draft, are unknown. Revenue
Administration of the 2008 year-end number of taxpayers are taken into account, the total number of 635 042
SMEs with capital companies and how it is not possible to determine the class will be included. In addition,
there is no reliable data for this number is how much active in our hands.
97
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
TYPE OF TAXPAĠRS
2004
2005
2006
2007
2008
Real People
Limited Company
Partnership
Joint-Stock Company
Others
Cooperative
Unlimited Company
Unincorporated Limited
Partnership
Limited Company with
Securities
Total
3.212.471
540.153
48.979
95.278
75.303
58.814
5.117
526
3.099.868
509.074
47.272
84.000
77.495
53.419
43.399
393
3.148.767
526.242
47.177
82.734
77.296
51.401
4.002
345
321.707
547.726
46.332
81.714
81.476
49.331
36.682
309
3.221.277
554.377
43.690
80.664
84.142
47.202
3.373
274
56
48
38
2
1
4.027.648
4.035.000
4.036.697
3.876.284
3.938.002
Table 4: Number of active taxpayers As species
The process of Implementation of standards in SME sized companies smooth the definition of SME
based on a key role. Accordingly, the bill's definition of SMEs should coincide with the IASB definition of
SME.
In the first section of standards Small and Medium Sized businesses definition explained.
Accordingly ,SMEs are defined as ―SMEs are Bussinesses without Public accountability obligations and
publish general purpose financial statements for external users‖. A company's public accountability
obligations that are Company's debt and equity instruments (stocks), domestic or foreign capital market or
over the counter market, including local and regional markets the public in an open market transactions, or
that such a market process to see these instruments exported in the process of being and existance . Assets,
with the title custodian be maintained on behalf of a large mass counterparts. (Banks, Investment Banks,
mutual funds, insurance companies, pension companies, pension funds, brokerage companies, factoring
companies, leasing companies and other financial institutions, etc.)
1523. draft of the article describes the capital stock companies according to the scale of companies.
Accordingly,
1. Companies that are not exceeded at least two of the following three criteria is considered to be small
capital stock companies:
Be found with taken out loss from asset Balance sheet total of six million TL
The last day of the accounting period (balance sheet day) of total sales in the previous twelve
months twelve million TL
Fifty people yearly average number of employees.
2. Companies that exceeds at least two criteria of the first paragraph and at least two of the following three
criteria are not exceeded two will be considered medium-size capital companies :
Be found with taken out loss from asset Balance sheet total of twenty million TL
The last day of the accounting period (balance sheet day) of total sales in the previous twelve
months fifty million TL
Two hundred and fifty-people yearly average number of employees.
3. Cabinet size can be increased up to ten times or ten or one to reduce.
4. In the second paragraph of the criteria for at least two of the largest companies in excess of capital is
considered capital firm.
A company that its Securities in Turkey securities exchange or traded securities in the list of the
countries declared each year from Capital Markets Board or traded to quotas have been or quotation for the
reference made in, have not exceeded this clause in the criteria shall be deemed to be even greater capital
company.
Projects in the SME definition, to the obligation of accountability to the public transmission to the
4. article of the indirect causes are no contradictions between the two definitions. Besides this, the bill is
clearly a wider scope of application. Ġt is clear that scope of application of the draft, is the larger than
definition. To the effect that for the implementation of standards,the obligation of non public accountability
condition in addition to publishing general-purpose financial statements for external users condition.
98
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
Accordingly, although the SME scale of a company may not apply this standard if it does not publish general
purpose financial statements . This situation could be used as, a "way out" particularly for micro-enterprises.
Such a practice is in draft form that is not in question.
Implementation of standards in Turkey, an EU accession perspective of Turkey is the other
dynamic. Turkey's EU-led negotiations process with regard 12.30.2008 dated Official Gazette "Turkey's EU
Acquis Compliance Program" in the Corporate Law with reference the commitment of the standard
application process is another decisive factor. Accordingly the TASB have new tasks to publish a new
application to comply with the EU's Fourth Directive based on the General Communiqué Accounting System,
and to publish a new application in order to adapt EU‘s Seventh Directive. With this published papers for
companies that have no obligation to public accountability will have been new arrangements compatible with
EU's fourth and seventh directives.In clear terms according to these commitments the Accounting Practice
General Communique ' published by the Ministry of Finance that the companies have to follow according to
the EU's Fourth Directive to be revised and the consolidation in accordance with the EU Seventh Directive
will need to create a new notification. This process is obvious that the bill had predicted structure and the
TASB Board of Education 's Financial Reporting Standards in Turkey is against the development perspective.
Under Compliance program in the case of arrangements of old accounting system we will not be compatible
with the International Financial Reporting Standards.The implementation of accounting standards for SMEs
have three dimension such as TCC Bill, Turkey's EU accession process and the perspective of TASB.These
three dimension will be balanced or conflicts will be eliminated.But It should be stated that these conflicts are
pointed a temporary situation. And This temporary situation largely disappeared with description of EU‘s
position and TCC draft be enacted
6. Conclusions
Disclosure of financial information of companies that have a full and fair benefit to all parts in the
economy. This is the obligation of accountability to the public until the company is also true for the SMEsize companies. In this context, the IFRS for SMEs issued by IASB is assuming a very important function.
The financial reporting standards for, SMEs are released SMEs, financial reporting quality, comparability and
to recognize information apply the to generate opportunities to all over the world and brings SMEs a chance
to open foreign markets.
The standard application of the provisions that the simpler from the full set of IAS / IFRS 's, but
also largely based on issues similar to the IAS / IFRS CPCs, SMEs when they pass large business class makes
a full set of IAS / IFRS applications easier.
International Financial Reporting Standards for SMEs are seperated from full set, taken into
consideration of SME needs,simplified without leaving IAS and IFRS‘s underlying philosophy,and which
introduced in various country.For this reason SMEs in Turkey implement these standards without undue delay
so that SMEs can easily find finance sourcing and open foreign markets.
Financial reporting standards for SMEs effective application contains a number of potential
problems and to have a significant majority of SMEs in the economy makes implementation of standards
difficult. First of all for the implementation of the standard needs to be transferred to domestic law. In this
issue priorities and preferences of each country is different. In Turkey, the process is no exception.
Ġmplementation of standards in Turkey must be enacted in the event of the draft become law of the TCC.
References
Akdoğan, Nalan.(2010).‖KOBĠ Finansal Raporlama Standartlarına Genel BakıĢ ve Tam Set IAS/IFRS‘lerden Farklılığı‖,
http://www.tmsk.org.tr/ makaleler/Diger/N_Akdoğan.pdf
Aslan, Sinan.(2007).Küçük ve Orta Büyüklükteki ĠĢletmeler(KOBĠ) Ġçin Uluslararası Finansal Raporlama Standartları
(UFRS) Ġle Global Uyum Süreci, The University of Marmara Journal, C.XXIII, S.2,s.203-221.
Çelik, Orhan. (2006). Uluslararası Finansal Raporlama Standartlarının KOBĠ‘lerde Uygulanması: Temel Dinamikler ve
Potansiyel Sorunlar. Ankara: TESMER Publication No. 73.
Çelik, Orhan. (2010). ―Küçük Ve Orta Büyüklükteki ĠĢletmeler Ġçin Uluslar arası Finansal Raporlama Standardı: Genel
BakıĢ‖. http://www.tmsk.org.tr/ makaleler/Diger/OrhanÇelik.pdf
99
�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
Demir,Volkan.(2007).‖KOBĠ‘ler Ġçin UFRS‖nin Son Taslağı ve Değerlendirmeler, Journal of Financial Solutions
Year:17, p.80,p.43-58.
IFRS For SMEs, International Financial Reporting Standard (IFRS) for Small and Medium-Sized Entities (SMEs),
Internatıonal Accountıng Standards Board (IASB), 2009.
Karakaya,Mevlüt.(2010).‖KOBĠ‘lerin Küresel Ekonomik Ġklime Uyumunda Uluslar arası Finansal Raporlama
Standartları‖. http://www.tmsk.org.tr/ makaleler/Diger/MEVLUT_KARAKAYA.pdf
Sayar,Zafer.(2008).‖Küçük ve Orta Büyüklükteki ĠĢletmelerin ÇağdaĢ Finansal Raporlama Dünyası: KOBĠ Muhasebe
Standartları‖.Ankara: TESMER Publication No:79.
Türkiye Muhasebe Standartları; TASB, 2010
100
�
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188
Title
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International Financial Reporting Standards for Smes and The Applicatıon Process In Turkey
Author
Author
CİVAN, Mehmet
KÖRPİ, Mehmet
BUYURAN, Burcu
Abstract
A summary of the resource.
Today, 95% of the world and in our country's economic system occurs from the Small and Medium-Large Enterprises (SMEs) constitute. Only the European Union, more than 25,000,000 and in our country 1.000.000 companies is estimated in the SME status. As shown the SMEs get a large share of sector ,the existence of their special structure, has become inevitable. One of these special structure, is financial reporting. Increasingly widespread use of International Financial Reporting Standards,the issue of how to implement those standards to SMEs, has been brought up. And for this problem in 2009 "SMEs for IFRS''was published. by IFRS. In this context, the basic aim of our study is to investigate and see the implemention proses of ―IFRS for SMEs‖ which resolve the differences of national accounting systems that applied in various countries of the world and will enable to comparison of financial reports and to see how affects and what would bring to Turkey‘s economic system.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
HB Economic Theory
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PDF Text
Text
Recent Developments in Biogas Production from Pulp and Paper Industry
Wastewaters
Kevser Cırık
Suleyman Demirel University, Dept. of Environmental Engineering, Isparta, Turkey
kewss_@hotmail.com
Veli Özdemir
Kahramanmaraş Sütçü Đmam University, Dept. of Bioengineering, Kahramanmaraş, Turkey
veli.85@hotmail.com
Emre Yazar
Kahramanmaraş Sütçü Đmam University, Dept. of Bioengineering, Kahramanmaraş, Turkey
emre_mishima@hotmail.com
Özer Çınar
Kahramanmaraş Sütçü Đmam University, Dept. of Environmental Engineering, Kahramanmaraş, Turkey
ocinar@alumni.clemson.edu
Abstract: Increase in population and rapid developments in technology have enhanced production
capacity in pulp and paper industry and have resulted in formation of huge amount of wastewaters,
as high as 6-15 x 104 L per ton of paper produced. Depending on the pulping process, wastewaters
can have a wide range of various pollutants characterized by biochemical oxygen demand (BOD),
chemical oxygen demand (COD), suspended solids (SS), toxicity, and dark color. Untreated
wastewaters from pulp and paper can be potentially very polluting especially for high COD
concentrations which can be reach at 13000 mg/L. Thus a reliable treatment process is needed to
reduce any possible impacts of wastewaters on the receiving media. To overcome this problem
an environmentally friendly and economically viable treatment technology should be applied.
Indeed, high organic content of pulp and paper industry wastewaters make anaerobic treatment a
very attractive option for these wastes. Anaerobic processes not only remove the wastewater
pollution but also can produce methane gas which is a valuable and renewable energy source. This
review evaluates the recent developments of treatment technologies that highlight to practical use
and economic availability of biogas production from pulp and paper wastewaters.
1.
Introduction
The rapid increase in population and the increased industrialization to meet human requirements have
created problems leading to the environmental danger. The pulp and paper industry which is the one of the most
important industries produces a wide range of different types of papers we use today such as; channeled carton
paper, newspaper, cleaning paper, cigarette paper, and bag paper. Normally paper production can be achieved by
the help of so many process steps and each step generates a wide range of various pollutants. Generated
pollutants from the wood pulping and production of the paper products have the potential of biochemical oxygen
demand (BOD), chemical oxygen demand (COD), suspended solids (SS), toxicity, and color (Pokhrel
andViraraghavan, 2004). Discharge of these wastewaters without any treatment poses a significant contributor
to the environment pollution, such as; organic pollution, scum formation, color problems, loss of aesthetic beauty
in the environment, and increase in toxic substances that affects terrestrial ecosystem (Berube and Kahmark,
2001). Thus a reliable treatment process is needed to reduce any possible impacts of wastewaters on the
receiving media. Before introducing the applied treatment technologies for these wastewaters, the process of
pulp and mill industry and characterization of the wastewaters generated in each step will be discussed briefly.
Treatment methods widely used in order to remove the pollution in the process of papermaking will be deeply
described in the subsequent sections.
598
�2.
Process Description of Pulp and Paper Mill Industry and Generated Effluents
2.1 Pulp and Paper Making Process
Pulping is the initial step of the paper making industry and represents the largest source of the pollution in
the whole process of papermaking. The whole process from wood preparation to paper production can be
classified into two categories, pulping and papermaking; respectively. Each process utilizes large amounts of
waters which are then turn into a wastewater stream. The paper making operation generally consists of two parts.
One is stock preparation by treating the pulp to the required degree of fitness and the other is paper making
where the treated pulp is passed through continuous moulds/wires to form sheets (Pokhrel andViraraghavan,
2004) (Table 1).
Paper
Making
Stock
Preparation
Bleaching
Wood
Pulping
preparation Process
Paper
Table 1. Paper Process
Widely used pulping processes are mechanical pulping, chemical pulping and a combination of the two
(chemical thermo-mechanical pulping). In the process of mechanical pulping wood is prepared for the
subsequent steps by a rotating grindstone in which the fibers are stripped of. When the wood is broken down
mechanically, the resulting pulp is known as groundwood pulp. Although mechanical pulping efficiency can
reach about 90-95%, the quality of the generated pulp is highly colored, and contains short fibers. Additionally,
this process does not require chemicals, but the lignin is not removed. In the process of the chemical pulping the
wood chips are transformed into fibrous mass by using appropriate chemicals under elevated temperature and
pressure in an aqueous solution. The main aim of this process is to remove the lignin by breaking it down and
make it soluble (Smook, 1992). This process is performed under two different process, kraft process, and sulfite
process; respectively. Kraft process requires alkali conditions in which woodchips are cooked in a solution of
sodium hydroxide (NaOH) and sodium sulfide (NaS2). Differently, in sulfite process woodchips are cooked in
mixture of sulfurous acid (H2SO3) and bisulfide ions (HSO3-) to dissolve lignin (Pokhrel andViraraghavan, 2004).
This process makes the wood free from lignin and hemi-cellulose and generated bagasse is used as energy source
by burning. Remaining liquor from this step is called as black liquor (Soloman, 2009). In addition, the process in
which the wood is first partially softened by chemicals and the remainder of the pulping proceeds with
mechanical force is called the chemical thermo-mechanical pulping. By the help of this step, the wood chips are
broken down and prepared for the next step.
The bleaching process is used for removal of colored compounds and lignin by chemical agents. In
bleaching process chlorine based oxidation agents are used such as hypochlorite, NaOCl, Cl2, ClO2, etc. On the
other hand there is also oxygen based oxidation agents used for bleaching such as (such as H2O2, Na2O2, O3, etc)
however their use as not widely as the chlorine based ones. Bleaching by the chlorine-based chemicals cause
production of degradation products in which various chloro organic derivatives can be seen. The bleaching
process technology and in-mill control is improving continuously. Finally, paper making processes is the last
step in which generated pulps is used as paper production including two parts. Initially, a stock is prepared by
treating the pulp to meet the required degree of fitness and then treated pulp is passed through continuous
moulds/wires to form sheets (Pokhrel andViraraghavan, 2004). In the preparation of stock, pulp is diluted to at
least 99% with water also some additives can be used such as optical brighteners and polyvinyl alcohol
(Hentzschel, 1998).
599
�2.2 Pulp and Paper Mill Effluent
Due to the diversity of processes and chemicals used in pulping and papermaking operations there is a
significant difference between the qualities of wastewaters produced from the both (Billings and DeHass 1971).
The major difference between the generated wastewaters is that pulp wastewater contains the dissolved wood
derived substances which are extracted from the wood during the process of pulping. Additionally, the other
difference between the pulp and paper mill effluents is the color of the effluents. Due to the dissolved lignin, all
pulping effluents including papermaking effluents have some discoloration. Actually, lignin is responsible for
the mechanical strength of the wood structure and gives the brownish color to the effluents (Leiviska, 2009).
Except for the color, pulp and paper mill effluents represent some other pollutants. The sources of pollution and
the generated pollutant features are summarized in Table 2. Although the availability of trace elements including
heavy metals in the effluents is not mentioned above, there have been published reports on the discharges of
metals and other elements from the pulp and paper industries.
Process
Description
Wood preparation
Pulping
Suspended solids (SS)
Biochemical oxygen
demand (BOD)
Fibers
High pH,
Biochemical oxygen demand (BOD)
Chemical oxygen demand (COD)
Adsorbable organic halides (AOX)
Volitile Organic Compounds (VOCs)
Suspended solids
Resins,
Fatty acids
Dissolved lignin,
Carbohydrate,
Color,
Inorganic chlorine compounds
Organo chlorine compounds
Features of
wastewaters
generated in
each step
Paper Making
Chemical oxygen demand
(COD)
Particulate waste,
Organic compounds,
Inorganic dyes,
Acetone
Table 2. The sources of pollution and the generated pollutant features (EPA, 1995)
3.
Treatment of Effluents
Pulp and paper industry generates large quantities of highly polluted wastewaters. The high water usage,
between 20,000 and 60,000 per ton of product results in large amounts of wastewater (Nemerow, 1991; Sinclair,
1990). Normally 150 m3 effluents are generated per ton paper produced (Ali, 2001). Effluents of the pulp and
paper making processes are widely expressed by its brownish color, high COD and high BOD. The effluent
generated at the pulping stage, which is called as black liquor, contains a wide range of compounds like
dissolved lignin and its degradation products, hemicelluloses, resin acid, fatty acids, tannins and phenols that are
also responsible for giving the effluent its characteristic dark brown color and toxicity (Ali, 2001; Lara, 2003;
Malaviya, 2007). Thus, the problems faced by the industry relate to the high organic content, toxicity and color.
Discharging of these wastewaters without any treatment applications can cause serious pollution problems. Thus
a reliable treatment method should be applied in order to meet discharge acceptance regulation. Mostly applied
treatment methods are physical, chemical and biological treatment methods as well as combination of different
methods in series. Application of chemical and physical methods has some disadvantages over the biological
treatment methods such as their cost-effectiveness and residual effects. Biological treatment is known to be
effective in reducing the organic load and toxic effects of pulp and paper mill effluent. There have been several
attempts to use biological methods to decontaminate effluent from kraft mills because of their ability to degrade
lignin by several microorganisms. The success of the biological treatment with respect to reduction organic load
and toxic effects of pulp and paper making effluents have been proven in so many research articles. Biological
treatment methods can be divided into two categories, aerobic and anaerobic; respectively. Aerobic treatment of
the pulp and paper making effluents has long been known and widely used for these purposes. Aerobic
treatments are effective for high COD and BOD removal efficiency (ranging from %70 to %90) but removal of
AOX which are known to toxic and hardly biodegradable, cannot be removed effectively, the overall removal of
600
�AOX from the effluents by aerobic treatment has been remained insufficient in so many situations (Savant,
2006). Alternatively, anaerobic treatment has become the most commonly used method not removes the
wastewater pollution but also can able to produce methane gas that known as a renewable energy source (Rintala,
1994). Anaerobic treatment is simple to operate, relatively inexpensive technology, moreover; it consumes little
energy. Pulp and paper making effluents are nutrient deficient. This feature of the effluent make anaerobic
treatment more convenient since commonly used COD: C: N ratio in aerobic treatment is 100:5:1 while it is
350:5:1 in the anaerobic treatment (Maat, 1990). In a study anaerobic treatment was found to reduce AOX and
COD by 73% and 66%, respectively. Also, when glucose was added to this effluent, there was generation of
biogas containing 76% methane (Ali and Sreekrishnan, 2000).
Typical COD removal data for the treatment of papermill wastewaters shows that a relatively constant
removal effciency of about 80% can be achieved and that the treated effluent has a COD concentration of about
800 mg/l. This COD concentration means that some form of additional treatment is required. Compairation of
two system was studied, the three-step sequential bioreactor treatments by anaerobic and aerobic (fungus and
aerobic bacteria) microorganisms and two step (fungus and aerobic bacteria), respectively and it was found that
microorganisms exhibited significant reduction in colour (88.5%), lignin (79.5%), chemical oxygen demand
(87.2%) and phenol (87.7%) in the two step aerobic sequential bioreactor, and colour (87.7%), lignin (76.5%),
chemical oxygen demand (83.9%) and phenol (87.2%) in the three-step anaerobic-aerobic sequential bioreactor.
They have concluded that in the anaerobic treatment, biogas is produced which can be utilized for energy
generation; however; aerobic treatment (aerobic fungus + aerobic bacteria) was more significant than anaerobic–
aerobic treatment (anaerobic + aerobic fungus + aerobicbacteria) (Chuphal et al. 2005). Numerous physicochemical processes have also been developed to remove a variety of toxic materials from pulp effuents and to
reduce parameters such as colour and COD. They include ozonation and adsorption, often in combination with
coagulation, which is used as a pre-treatment stage (Thompson et al., 2001). Bishnoi et al. (2006) reported the
biodegradation of pulp and paper mill effluent using anaerobic followed by aerobic treatment. Using a
continuous stirred tank reactor (CSTR) for anaerobic digestion of black liquor, these authors reported a
maximum methane production was found up to 430 ml /day.
a.
Biogas Production
The interest in biogas production has grown considerably for the most of the industries. Anaerobic
treatment producing methane that can be directly used as a source of energy has long been employed in
industrial waste treatment. Anaerobic treatment is an effective means of decreasing the organic content of
different wastewaters in the absence of oxygen (Noykova et al., 2002). Application of aerobic treatment is not
commonly preferred due to the cost of oxygen supplementation and generation of higher sludge quantities and
odors (Gavala et al., 1999). For the treatment of pulp and paper mill effluents, anaerobic digestion is essentially
viable method due to waste reduction and energy potential. Actually anaerobic digestion consists of three main
stages. The first step of anaerobic digestion called hydrolysis; complex organic molecules are broken down into
simple sugars, amino acids, and fatty acids with the addition of hydroxyl groups which is accompanied by a
rapid decrease in pH (Goblos et al., 2008). Step 2 is a fermentation process where acid-forming bacteria, also
known as acidogens, convert the products of hydrolysis into simple organic acids, alcohols, carbon dioxide, and
hydrogen gas. Finally, end-products of the fermentation process (acetate, butyrate, propionate etc.) are converted
by methanogenic microorganisms into methane and carbon dioxide, together with trace quantities of other gases
(Fig. 1).
In brief, two groups of methanogenic organisms are involved into the methane production; one group
splits acetate into methane and carbon dioxide, and the second group uses hydrogen as electron donor and carbon
dioxide as electron acceptor to produce methane. In general, biogas produced as end-product of anaerobic
digestion consists of about 65–70% methane, 30–35% carbon dioxide and trace amounts of nitrogen, hydrogen,
hydrogen sulphide and water vapor. It is the methane component of the biogas that will produce energy. The gas
can be used to generate heat or electricity or both. Anaerobic treatment seems adequately not only removing the
wastewater pollution but also producing methane gas which can be used for the energy requirement of the
industry. Anaerobic wastewater treatment is typically used in different industries such as chemical, dairy, and
pulp and paper mills. Application of anaerobic treatment of pulp and paper industry has been investigated by so
many researchers. It has been noted that the adoption of this technology by pulp and paper industries has been
limited, mainly due to the 30–60 day residence times required to process the sludge in conventional bioreactors
(Elliott and Mahmood, 2007). The published reports that evaluate the recent developments of treatment
technologies will be briefly discussed by means of biogas production from pulp and mill wastewaters and solid
wastes.
601
�Figure 1. Anaerobic Methane Production
Anaerobic biogas production is actually a sensitive process. Presence of toxic materials in the effluent can
be result in deterioration of the process which is undesirable. Unfortunately, pulp and paper industry effluents
mainly contains high amount of lignin, adsorbable organic halide, color, low biodegradability (COD: BOD, 4–6)
and potential toxicity problems. Inhibitory agents that can be found in pulp and paper industry effluents are
summarized in Table 3. Providing that biomass is protected from toxic materials biogas production from pulp
and paper industry can be successfully managed.
Wastewater
Pulping
• Thermomechanical
• Chemithermomechanical
COD
(mg/L)
Degradation
(%)
Inhibitors
1000-5600
2500-13000
60-87
40-60
Resin Acids
Resin Acids, fatty acids, sulfur
30-50
-
Sulfur, ammonia
Chlorinated phenols, resin acids
Kraft condensate
7000
900-2000
120000220000
1000-33600
83-92
Sulfite condensate
7500-50000
50-90
Sulfur, resin acids, fatty acids,
terpenes
Sulfur, organic sulfur
Sulfite condensate
Chlorine bleaching
Sulfite spent liquor
Table 3. Inhibitors to methanogens in the effluent of pulp and paper industry (Rintala et al., 1994)
In the process of chlorine bleaching, so many toxic substances that affect the methanogens can be
released. Also it is well known that chlorinated phenolics and chlorinated lignin derivatives are among the main
chemical species responsible for the toxicity of pulp and paper mill effluents. Resin acids are tricyclic diterpenes
that occur naturally in the resin of tree wood and bark and are transferred to process waters during pulping
operations. Several workers have reported the accumulation of resin acids in anaerobic reactors treating
mechanical pulping wastewaters. It was reported in a study that inhibition of methanogenic activity of the
anaerobic consortium was noted at initial resin acid/biomass ratios exceeding 0.0031 mg resin acid/mg VSS. In
addition to resin acids, unsaturated fatty acids, such as; oleic acids, linoleic acid and linolenic acid from pulp and
paper mills employing softwood are also a source of toxicity. Since fatty acids can be degraded anaerobically, it
is not entirely necessary to prevent them from entering the anaerobic reactors, however; the concentrations
present in the wastewater should be kept below the maximum allowable level so that they do not cause
significant inhibition to the anaerobic bacteria. For the removal of phenolic compounds white rot fungi have
proved their potential in the lignin/phenolic wastewater treatment (Eaton et al. 1980). They have proved ideal
organisms for decolorization as well as for the reduction of adsorbable organic halides (AOX) and the chemical
oxygen demand (COD). Several researches have also shown that kraft mill effluents can be partly decolorized by
white rot fungi (Gokcay and Dilek 1994).
602
�For these reasons, the resent studies have been focused on the application of pretreatment technologies
before anaerobic treatment in order to enhance biogas production. There are a number of physical, chemical or
biological techniques (use of fungus and bacteria) to minimize the inhibitory effects of effluents prior to
anaerobic treatment systems (Lettinga et al. 1991). Reactor design for anaerobic biogas production is also
important. The use of thermophilic digesters has recently become more attractive due to their superior
performance, better pathogen destruction, and higher digestion rates, which allow the anaerobic digestion
facilities to operate at higher loading rates. Using two-stage systems, which segregate the formation of volatile
fatty acids from methanogenesis, have also been developed, improving the overall digester performance. In a
study performed by Yamini et al. (2009), Upflow anaerobic fixed packed bed reactor (UAFPBR) with brick
ballasts as packing material was used in order to treat pulp and paper mill effluents. They have studied biogas
production from paper and mill organic sludge in combination with fermented municipal sludge and cattle
manure as inoculum. They have found that with a optimum hydraulic retention time (HRT) of 12 hr, reduction of
74.5% COD and 81% BOD was obtained. Additionally 30% inoculum concentration was best for the anaerobic
treatment of the effluent with a maximum biogas production of 1.37 L / L effluent.
Beside pulp and paper effluents, pulp and paper industry solid wastes are also valuable for biogas
production. In the late 1980s and early 1990s, several research articles have been published introducing
anaerobic digestion for treating pulp and paper solid wates (Kowalczyk and Martynelis, 1989; Puhakka et al.,
1988; Puhakka, 1991). The long residence time requirement of anaerobic sludge digestion has historically
deterred its use in the pulp and paper industry. Techonological advancement that potentially can make anaerobic
digestion more feasible has been the development and establishment of pretreatment of sludge prior to anaerobic
digestion to accelerate the hydrolysis of sludge. Pretreatment enhances sludge digestion and the rate and quantity
of biogas generated, thereby reducing the retention time requirement from 15 to 25 days to approximately 7 days.
The studies were performed on both laboratory and pilot-scale systems. Generally, the results of these studies
showed that anaerobic digestion of pulp and paper biosolids could reduce solid wastes by 30–70%, with the
benefit of methane production. Studies were focused on cost and benefits of the anaerobic technology if
pretreatment technologies, including high temperature, sonication, high-pressure homogenization, addition of
acids and bases, or addition of enzymes, have been developed to solubilize the organic fraction of secondary
sludge (Elliott and Mahmood, 2007; Barjenbruch and Kopplow, 2003; Bougrier et al., 2006; Chen et al., 2007;
Khanal et al., 2007; Penaud et al., 1999; Tanaka et al., 1997; Valo et al., 2004). In addition to microbial biomass,
pulp mill secondary sludge can contain residual cellulose, lignin and chemical components from the pulping
process (Kyllönen et al., 1988). In a study performed by Wood (2009), thermal and caustic pretreatment can
significantly increase both the extent and rate of anaerobic bioconversion of pulp mill secondary sludge to biogas.
4. Conclusion
The pulp and paper industry is considered to be a highly energy intensive and polluting industry. In recent
years, the high cost of energy inputs and increased environmental concerns are forcing the pulp and paper
industry to look for cost-effective and environmentally friendly alternatives. The general characteristics of the
pulp and paper industry effluent can be listed as:
1.
2.
3.
4.
5.
High lignin content,
High adsorbable organic halide (AOX) concentration (due to the bleaching process),
Color,
Low biodegradability which is indicated by their high chemical oxygen demand to biochemical oxygen
demand ratios (COD/BOD), often in the range of 4–6,
Potential toxicity problems
Although physical and chemical methods are available for treatment of pulp and paper mill effluent, they
are less desirable than biological treatment because of cost-ineffectiveness and residual effects. Biological
treatment is known to be effective in reducing the organic load and toxic effects of pulp and paper mill effluent.
Since the early 1980s anaerobic treatment of industrial effluents has found widespread application in the pulp
and paper industry. Over 200 anaerobic plants are treating a large variety of different pulp and paper mill
effluents. Anaerobic fermentation is especially valuable because its end product is methane, a renewable energy
source. In the resent years, studies were performed on pretreatment techonologies to decrease toxicity of the
effluent prior to anaerobic treatment. Advantages of anaerobic pretreatment are net production of renewable
energy (biogas), minimised biosolids production and reduced emission of greenhouse gases. Anaerobic treatment
of pulp and paper effluents combination with manure (co-digestion) has emerged among the new treatment
603
�perspectives for these effluents. Additionally, other energy source is the anaerobic pulp and paper solid wates.
The long residence time requirement of anaerobic sludge digestion has prevented its use in the pulp and paper
industry. In an attempt to decrease the residence time requirement, pretreatment technologies have been
developed in the recent years such as; high temperature, sonication, high-pressure homogenization, addition of
acids and bases, or addition of enzymes. These pretreatment techonologies have been developed to solubilize the
organic fraction of secondary sludge. Some of these technologies, using physical or chemical principles, and
often a combination of them, have demonstrated their ability to substantially reduce the digestion time and
thereby the reactor size. Increased gas production and reduced excess sludge generation have been reported to be
the added benefits associated with them.
References
Ali M., T.R. (2001). Sreekrishnan, Aquatic toxicity from pulp and paper mill effluents: a review, Adv. Environ. Res. 5 175–
196.
Ali M., Sreekrishnan T.R. (2000). Anaerobic treatment of agricultural residue based pulp and paper mill effluents for AOX
and COD reduction Process Biochemistry 36, 25–29.
Barjenbruch, M., Kopplow, O. (2003). Enzymatic, mechanical and thermal pretreatment of surplus sludge. Adv. Environ. Res.
7, 715–720.
Bishnoi, N.R., R.K. Khumukcham and R. Kumar. (2006). Biodegradation of pulp and paper mill effluent using anaerobic
followed by aerobic digestion. J. Environ. Biol., 27, 405-408
Berube PR, Kahmark KA. (2001). Pulp and paper mill effluents. Water Environ Res; 73(5):1– 36
Billings, R.M., DeHaas, G.G. (1971). Pollution control in the pulp and paper industry. In: Lund, H.F. (Ed.), Industrial
Pollution Control Handbook. McGraw-Hill, New York.
Bougrier, C., Albasi, C., Delgenès, J.P., Carrère, H., (2006). Effect of ultrasonic, thermal and ozone pre-treatments on waste
activated sludge solubilisation and anaerobic biodegradability. Chem. Eng. Process. 45, 711–718.
Chen, Y., Jiang, S., Yuan, H., Zhou, Q., Gu, G., (2007). Hydrolysis and acidification of waste activate sludge at different pHs.
Water Res. 41, 683–689.
Chuphal Y, Kumar V and Thakur I S (2005). Biodegradation and decolorization of pulp and paper mill effluent by anaerobic
and aerobic microorganisms in a sequential bioreactor World Journal of Microbiology & Biotechnology 21:1439–1445.
Eaton, D., Chang, H.M. and Kirk, T.K. (1980) Fungal decolourization of kraft bleach plant effluents. Tappi 63(10), 103-106.
Elliott, A., Mahmood, T., (2007) Pretreatment technologies for advancing digestion of pulp and paper biotreatment residues.
Water Res. 41, 4273–4286.
Gavala, H., Kopsinis, H., Skiadas, I., Stamatelatou, K., Lyberatos, G.,(1999) Treatment of dairy wastewater using an upflow
anaerobic sludge blanket reactor” J Agric Eng Resources, Vol. 73, pp. 59–63.
Goblos, S.Z., Portoro, P., Bordas, D., Kalman, M., Kiss, I., (2008) Comparison of the effectivities of two-phase and singlephase anaerobic sequencing batch reactors during dairy wastewater treatment” Renewable Energy, Vol. 33, pp. 960-965.
Gokcay FC, Dilek FB. (1994) Treatment of effluents from hemp-based pulp and paper industry (2) biological treatability of
pulping effluents. Water Sci Technol; 29(9):165– 8.
Hentzschel P., Martin G., Pelzer R., Winkler, K., (1998). Steps towards optimized paper brightness. Wochenbl. Papierfab.
126, 176-180.
Khanal, S.K., Grewell, D., Sung, S., Van Leeuwen, J., (2007) Ultrasound applications in wastewater sludge pretreatment: a
review. Crit. Rev. Environ. Sci. Technol. 37 (4), 277–313.
Kowalczyk A.,M.Martynelis, (1989) Study of anaerobic treatment ofwaste sludge from the [Pokish] pulp and paper industry,
Przeglad Paper 45 (12) 431–434.
Kyllönen, H.L., Lappi, M.K., Thun, R.T., Mustranta, A.H., (1988)Treatment and characterization of biological sludges from
the pulp and paper industry. Water Sci. Technol. 20 (1), 183–192.
604
�Lara M.A., Rodrguez-Malaver A.J., Rojas O.J., Holmquist O. Gonzalez A.M, Bullon J., Penaloza N., Araujo E., (2003).
Black liquor lignin biodegradation by Trametes elegans, Int. Biodet. Biodegrad. 52 167–173.
Leiviska T., Ramo J., Nurmesniemi H., Poykio R., Kuokkanen T. (2009). Size fractionation of wood extractives, lignin and
trace elements in pulp and paper mill wastewater before and after biological treatment WaterResearch, 43 (13), pp. 3199
3206.
Lettinga, G., Field, J.A., Alvarez, R.S., Vanlier, J.B., Rintala, J.B., (1991) Future perspectives for the anaerobic treatment of
forest industry wastewaters. Water Sci. Technol. 24, 91±102.
Maat, D.Z. (1990). Anaerobic treatment of pulp and paper effluents. In Proceedings TAPPI 1990 Environmental Conference,
TAPPI press, Atlanta, GA, pp. 757-9.
Malaviya P., Rathore V.S., (2007). Bioremediation of pulp and paper mill effluent by a novel fungal consortium isolated
from polluted soil, Biores. Technol. 98 3647–3651.
Nemerow NL, Dasgupta A. (2001). Industrial and hazardous waste management. New York: Van Nostrand Reinhold.
Noykova, N., Muller, T.G., Gyllenberg M., Timmer J., (2002) Quantitative analysis of anaerobic wastewater treatment
process: identifiability and parameter estimation, Biotechnol Bioeng, Vol. 78, pp. 89–103.
Penaud, V., Delgenès, J.P., Moletta, R., 1999. Thermo-chemical pretreatment of a microbial biomass: influence of sodium
hydroxide addition on solubilization and anaerobic biodegradability. Enzyme Microb. Technol. 25, 258–263.
Pokhrel D., Viraraghavan T. (2004). Treatment of pulp and paper mill wastewater Science of the Total Environment 333
37– 58
Puhakka J., (1991) Anaerobic sludge digestion in industrial wastewater treatment, Water Sci. Technol. 24 (1) 61–68.
Puhakka J.A., Viitasaari M., Latola P., Maatta R., (1988) Effect of temperature on anaerobic digestion of pulp and paper
industry waste water sludges, Water Sci. Technol. 20 (1) 193–201.
Rintala J.A., Puhakka J.A. (1994) Anaerobic treatment in pulp- and paper-mill waste management: A review Bioresource
Technology, 47 (1), pp. 1-18.
Savant D.V., Abdul-Rahman R., Ranade D.R. (2006) Anaerobic degradation of adsorbable organic halides (AOX) from pulp
and paper industry wastewater Bioresource Technology, 97 (9), pp. 1092-1104.
Sinclair WF. (1990) Controlling pollution from Canadian pulp and paper manufactures: a federal perspective Ottawa:
Canadian Government Publishing Centre.
Smook GA. (2001) Handbook for pulp and paper technologist. Vancouver Bellingham: Angus Wilde Publications.
Soloman P.A., C. Ahmed Basha, M. Velan, N. Balasubramanian, P. Marimuthu, (2009) Augmentation of biodegradability of
pulp and paper industry wastewater by electrochemical pre-treatment and optimization by RSM, Separation and Purification
Technology, Volume 69, Issue 1 , Pages 109-117, ISSN 1383-5866.
Tanaka, S., Kobayaski, T., Kamiyama, K., Bildan, S., Ma, L.N., (1997) Effects of thermochemical pretreatment on the
anaerobic digestion of waste activated sludge. Water Sci. Technol. 35, 209–215.
Thompson G., Swain J., Kay M., Forster C.F (2001) The treatment of pulp and paper mill effluent: A review Bioresource
Technology, 77 (3), pp. 275-286.
US EPA. EPA (1995) Office of compliance sector notebook project: profile of pulp and paper industry. Washington, DC
20460, USA: EPA/ 310-R-95-015.
Valo, A., Carrère, H., Delgenès, J.P.,( 2004) Thermal, chemical and thermo-chemical pre-treatment of waste activated sludge
for anaerobic digestion. J. Chem. Technol. Biotechnol. 79, 1197–1203.
Yamini S, Deepak P, Anoop SRK, Srivastava (2009) Treatment of rayon grade pulp drain effluent by upflow anaerobic fixed
packed bed reactor (UAFPBR), Journal of Environmental Biology, 30(5) 667-672.
Wood N., Tran H., Master E. (2009) Pretreatment of pulp mill secondary sludge for high-rate anaerobic conversion to
biogasBioresource Technology 100 5729–5735.
605
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607
Title
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Recent Developments in Biogas Production from Pulp and Paper Industry Wastewaters
Author
Author
Cırık, Kevser
Özdemir, Veli
Yazar, Emre
Çınar, Özer
Abstract
A summary of the resource.
Increase in population and rapid developments in technology have enhanced production capacity in pulp and paper industry and have resulted in formation of huge amount of wastewaters, as high as 6-15 x 104 L per ton of paper produced. Depending on the pulping process, wastewaters can have a wide range of various pollutants characterized by biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), toxicity, and dark color. Untreated wastewaters from pulp and paper can be potentially very polluting especially for high COD concentrations which can be reach at 13000 mg/L. Thus a reliable treatment process is needed to reduce any possible impacts of wastewaters on the receiving media. To overcome this problem an environmentally friendly and economically viable treatment technology should be applied. Indeed, high organic content of pulp and paper industry wastewaters make anaerobic treatment a very attractive option for these wastes. Anaerobic processes not only remove the wastewater pollution but also can produce methane gas which is a valuable and renewable energy source. This review evaluates the recent developments of treatment technologies that highlight to practical use and economic availability of biogas production from pulp and paper wastewaters.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
Q Science (General)
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https://omeka.ibu.edu.ba/files/original/a2053553f2789df556ec7dea6f204df4.pdf
da382aee3f43206f973b34757ef8c75d
PDF Text
Text
Parameters Affecting Polyhydroxyalkanoate Synthesis from Wastewaters
Kevser Cırık
Suleyman Demirel University, Dept. of Environmental Engineering, Isparta, Turkey
kewss_@hotmail.com
Dilek Aydoğmuş
Kahramanmaraş Sütçü Đmam University, Dept. of Bioengineering, Kahramanmaraş, Turkey
aydogmus86@hotmail.com
Şebnem Özdemir
Kahramanmaraş Sütçü Đmam University, Dept. of Bioengineering, Kahramanmaraş, Turkey
sebnemozdemir55@hotmail.com
Mehmet Gezginci
Kahramanmaraş Sütçü Đmam University, Dept. of Bioengineering, Kahramanmaraş, Turkey
mehmetgezginci@gmail.com
Özer Çınar
Kahramanmaraş Sütçü Đmam University, Dept. of Environmental Engineering, Kahramanmaraş, Turkey
ocinar@alumni.clemson.edu
Abstract: Plastics used almost every manufacturing industry are resist to biodegradation. Their
persistence in soil for a long time has become a major concern in terms of the environment.
This promotes many investigators to search for replacement of non-biodegradable by
degradable plastics. Polyhydroxyalkanoates (PHAs), known as a biodegradable plastic
produced by bacteria, have received increasing attention due to the difficulties in disposal of
plastics. In recent years, researchers have focused on the processes to increase PHA production
which involve in biological phosphorus removal (BPR). Normally, BPR can be achieved
through anaerobic- aerobic cycling by a group of bacteria known as polyphosphateaccumulating organisms (PAOs). PHA is stored within the PAO as carbon polymers under
anaerobic conditions by taking up volatile fatty acids (VFAs), further it is used as energy
source and phosphorus uptake under aerobic conditions. The aim of this review is to discuss
recent advances in PHA production from wastewaters and parameters effecting PHA
production efficiency.
1. Introduction
Plastics which are known to be widely used in almost every manufacturing industry are very much
advantageous. Plastics are popular in many durable, disposal goods and as packaging materials. Beside a wide
range of benefits, they are not desirable in the environment. Especially, plastics are known as hardly
biodegradable even non-biodegradable due to the fact that they mainly have high molecular weights (Reedy et
al., 2003). Their persistence in soil for a long time has become a major concern in terms of the environment. This
promotes many investigators to search for replacement of non-biodegradable by degradable plastics. An
alternative approach to conventional plastics is Polyhydroxyalkanoates (PHAs) which are known as a
completely biodegradable plastic produced by bacteria, have received increasing attention due to the difficulties
in disposal of plastics (Bengtsson et al., 2008). Additionally, Poly-(R)-3-hydroxybutyric acid (PHB) and
hydroxyvalerate (PHV) are among the most common PHA monomers. The chemical structure of the PHAs is
shown in Figure1.
579
�Figure 1. Chemical structure of PHAs (Lee, 1996)
2. PHA Production
As mentioned before, the PHAs are non-toxic, biocompatible, biodegradable thermoplastics that can be
produced from renewable resources such as biomass. These biopolymers accumulate as storage materials in
microbial cells under stress conditions (Sudesh et al., 2000; Chen et al., 2001; Kadouri et al., 2005). Many grampositive and gram-negative bacteria are known to be able to synthesize PHAs (Reedy et al., 2003). PHAs can be
produced through anaerobic- aerobic cycling by a group of bacteria known as polyphosphate-accumulating
organisms (PAOs). Although PAOs are often present in a wide range of aerobic suspended growth cultures, they
only have the ability to store large quantities of phosphate when they are subjected to alternating anaerobic and
aerobic conditions. PHA is stored within the PAO as carbon polymers under anaerobic conditions by taking up
volatile fatty acids (VFAs), further it is used as energy source and phosphorus uptake under aerobic conditions
(Figure 2). Under aerobic conditions stored PHA or PHB within the cell is used as energy source for biomass
growth, and glycogen synthesis.
A
B
Figure 2. Anaerobic PHA production and phosphorus release (A), aerobic PHA utilization and phosphorus
uptake (B) within the cell (Lee and Choi, 1999)
Recently reported research articles have been performed to understand PAO metabolism (Seviour et al.,
2003). Acetate has been used almost exclusively as the carbon source in these studies, partially explained by the
fact that it is typically the largest volatile fatty acid (VFA) species present in the wastewater treatment plants.
Metabolic PAO models for anaerobic acetate uptake and utilization and the subsequent aerobic processes have
been proposed. As depicted in Figure 2, anaerobic process is based on fermentation in which poly-P degradation
and phosphate release take part. Under anaerobic conditions with acetate as the carbon source, phosphate
580
�accumulating microorganisms can take up acetate rapidly, accumulate PHAs in the cell. The energy for this
biotransformation is mainly generated by the cleavage of polyphosphate and release of phosphate from the cell.
They consume previously stored intracellular carbohydrate, and release P as a result of utilization of stored polyP. Thus, wastewater from anaerobic process is rich in inorganic phosphate. In aerobic processes, oxygen is
electron acceptor and microorganism use stored PHB as their carbon and energy source.
PAOs are actually known as responsible for enhanced biological phosphorus removal (EBPR) and have a
key role with respect to both PHB accumulate within the cell and phosphorous removal. The process is one of
the most commonly used and environmentally sounds methods for phosphorus (P) removal from wastewater. As
mentioned before, VFAs are preferable substrates for PHA production. Anaerobic fermentation converts various
organic compounds to VFAs hence increasing the potential to produce PHA from the wastewater. The
composition of the VFAs produced during fermentation will influence the final polymer product. However, the
number of literature reports for PHA production with mixed cultures enriched with real wastewaters is limited.
•
PHAs Extraction from the Cell
Since PHAs are accumulated within the cell, it should be extracted to be able to be used as plastic
polymers. However, the extraction of bioplastics from microorganism poses yet a challenge. There are two
common protocols used for PHA extraction from bacteria. The first protocol is developed by taking into
consideration of solubility in chloroform and insolubility in methanol. Harvested bacterial cells are exposed to
warm chloroform to make PHAs soluble. Further, residuals from harvested bacteria such as lipids and other
lipophilic components are removed by reflux in hot methanol. Purified PHA production efficiency of this
protocol is high. However, requirements of a large amount of hazardous solvent make it not environmentally
friendly (Lee, 1996). The second protocol developed for the aim of avoiding organic solvent usage. In this
protocol, a mixture of enzymes are used such as proteases, nucleases and lysozymes, additionally to remove
proteins, nucleic acids, and cell walls, detergents are used.
3. Factors Affecting PHB Production
In the previous sections the importance of PAOs on PHB production and phosphorus removal from the
wastewaters were emphasized. However, their production costs are much higher than the petrochemical- based
plastics (Fang et al., 2009). Thus, it becomes inevitable to know parameters affecting PHA production efficiency
within the cell such as; microorganisms involved, pH, substrate, solid retention time (SRT), availability of
electron acceptors, and temperature. These will be briefly discussed by taking into account the published
research articles that focus on increasing the cost-effectiveness of this process.
a.
Microbial Population
Determination of microbial population that involve in PHB production and phosphorous removal is one
of the most important factor to be able to make the process successful. It has been emphasized in so many
articles that there is a competition between two microorganisms, PAOs and glycogen (non-polyphosphate)
accumulating organisms (GAOs) respectively. Like PAOs, GAOs are able to proliferate under alternating
anaerobic and aerobic conditions but the problem is they do not contribute to P removal hence anaerobic P
release or aerobic P uptake cannot be established. This constitutes a major challenge since PHA production
without any phosphorous removal cannot be convenient according to discharge regulations. Additionally, the
presence of GAOs increase the anaerobic VFA requirements of these plants, thus so many investigators have
focused on the ways that minimize the growth of GAOs. Factors affecting GAOs and PAOs competitions can be
summarized as:
6. One factor affecting the PHA accumulation is the ratio of organic carbon to P in the influent or the so-called
COD: P ratio. In so many studies it was reported that a high COD/P ratio (e.g. 450mgCOD/mgP) in the
wastewater feed tends to favorable the growth of GAOs instead of PAOs while a low COD/P ratio (e.g. 10–
20mgCOD/mgP) tends to favorable to the growth of PAOs (Oehmen et al., 2007).
7. Effect of pH has been reported in so many research articles. They have found that increase in pH from 6.57.5 is favorable for PAOs while is not favorable for GAO. Thus it is possible to eliminate GAOs by
increasing pH. In a study performed by Filipe et al., (2001a) has shown that P uptake, PHA utilization and
biomass growth were all inhibited by a low pH (6.5), and suggested that a higher aerobic pH (7–7.5) would
be more beneficial for PAOs.
581
�8. Effect of temperature is also investigated by so many researches and they concluded that GAOs are inhibited
at 10 ºC since PAOs are the dominant microorganisms at low temperature (Carlos et al., 2009). It was also
noted that high temperatures (30 ºC) can suppress the proliferation of GAO in which operating conditions for
pH is high (>7) and an adequate acetate to propionate ratio (75–25%) is supplied. The experimental evidence
obtained thus far suggests that GAOs tend to become stronger competitors with PAOs at higher temperatures.
b.
pH
In many studies it was shown that adjusting to pH higher levels results in a higher anaerobic P release
(Smolders et al., 1994; Liu et al., 1996; Bond et al., 1999; Filipe et al., 2001b). Kasemsap et al., (2007) found
that increasing the pH from 6 to 8 promoted the PHA production significantly. It was also reported in other study
that the ratio of anaerobic P release to acetate uptake increase from 0.25 to 0.75 P-mol/C-mol by increasing pH
from 5.5 to 8.5 (Smolders,1994). Actually, by adjusting pH GAOs can be eliminated, this is the reason for why
so many researchers focus on its effects.
Increase in pH makes the energy requirements for substrate uptake high. When external pH is high, more
energy is needed for acetate uptake. This increased energy is generated through an increase in polyphosphate
degradation. This scenario has been found ineffective for the acetate uptake, glycogen degradation and PHA
accumulation rates of PAOs when the pH is over the range 6.5–8.0 (Filipe et al., 2001b). Nevertheless, this
situation is rather different for the GAOs. It was reported that a higher pH results in a higher energy demand for
acetate uptake, but negatively affects the ability of GAOs to take up acetate. This is obviously related to the
differences between metabolic pathways of the microorganisms. The energy production pathways of GAOs and
PAOs are dissimilar since PAOs use the energy required for the substrate uptake from the hydrolysis of poly-P
while GAOs from the hydrolysis of glycogen (Smolders et al., 1994; Filipe et al., 2001a,b). That means PAOs
have poly-P as an extra energy source as compared to GAOs and they deplete it to meet higher energy demand.
In a published report performed by Chua et al.(2003) studied the effect of pH on the PHA content using acetate
as the substrate. They found that, through controlling the pH at 6 or 7, the PHA content (less than 5%) was lower
than at pH 8 or 9 (25–32%). Like this record, Serafim et al., (2004) was found that polymer yield per substrate
and the intracellular PHB content were higher at pH 8 than at pH 7.
c.
Substrate
It is a prerequisite to optimize all the fermentation conditions for the successful implementation of
commercial PHA production systems. Actually there is a major challenge to reduce PHA production costs.
Carbon source has a large impact on production cost of the PHA produced. Hence, recent studies have been
focused on reducing costs. The price of the product ultimately depends on the substrate cost, PHA yield on the
substrate, and the efficiency of product formulation in the downstream processing.
In so many studies different substrates were used to improve the predictability of the metabolism of both
PAOs and GAOs. Acetate has been used almost exclusively as the carbon source. It has been well known that
short chain fatty acids like acetate are favorable carbon sources for PAOs. Beside acetate, there are so many
carbon sources used in order to investigate PHA production pathway, such as; lactate, propionate, sucrose,
glucose, cheese whey, cane molasses, methanol, and hemicelluloses hydrolsate (Quillaguaman et al., 2007; Ahn
et al., 2000; Wong and Lee, 1998; Rhu et al., 2003; Hong et al., 2000). Waste materials or industrial by-products
can also be used for PHA production. However it was reported that carbohydrates are not directly stored as PHA
and they are tend to be preferentially accumulated as glycogen (Dircks et al., 2001; Karahan et al., 2006). PHA
production from raw materials requires a previous anaerobic fermentation step for their transformation into
volatile fatty acids (VFA). This is the reason why the majority of the studies related to PHA production are based
on the use of organic acids. The effect of various substrate costs, the yield on the P (3HB) and production cost
are summarized in Table 1.
Wastewater contains a much more diverse mixture of substrates other than acetate and investigations
were conducted with other compounds, alone or in mixtures, including: propionate, butyrate, valerate,
isovalerate, formate, lactate, malate, pyruvate, glucose, citrate, succinate but glutamate but the metabolism of
these organic substrates have not yet been well understood (Wang et al., 2002). Several studies concluded that
glucose as sole carbon source led to deterioration of the EBPR process, as glucose promoted the growth of
GAOs which do not accumulate polyphosphate and therefore capable of utilizing glucose without the release of
phosphate (Cech and Hartman, 1993; Mino et al., 1994; Satoh et al., 1994; Tasli et al., 1997). However, there are
also opposite research results where a stable EBPR performance could be maintained with glucose as the major
organic substrate, with no appreciable proliferation of GAOs (Carucci et al., 1999; Jeon and Park, 2000; Wang et
al., 2002).
582
�Substrate
Glucose
Sucrose
Methanol
Acetic acid
Ethanol
Cane molasses
Cheese whey
Hemicellulose hydrolysate
Substrate Price
(US$ kg_1)
0.493
0.290
0.180
0.595
0.502
0.220
0.071
0.069
P(3HB) yield
(g P(3HB) (g substrate)_1)
0.38
0.40
0.43
0.38
0.50
0.42
0.33
0.20
Product cost
(US$(kg P(3HB))_1)
1.30
0.72
0.42
1.56
1.00
0.52
0.22
0.34
Table 1. Effect of various carbon sources on PHB yield and production cost (Reddy et al., 2003)
In the past, there have been relatively few studies on EBPR systems involving propionate as a carbon
source (Satoh et al., 1992,). In recent years, however, the metabolism of propionate by PAOs (Lemos et al.,
2003) and its effect on EBPR performance has attracted considerable attention. Several studies have suggested
that propionate could be a more favorable substrate for EBPR (Chen et al., 2004; Thomas et al., 2003), likely
providing a selective advantage to PAOs over GAOs (Oehmen et al., 2004a, 2004b; Pijuan et al., 2004). In the
studies used other single substrates such as lactate, ethanol, and glutamate which can be converted into PHB,
very low storage yield has been obtained. When lactate used for carbon source, 0.20 g PHA g-1 substrate
accumulation was obtained, it was 0.25 g PHA g-1 substrate for ethanol, and 0.058 g PHA g-1 substrate for
glutamate (Dionisi et al., 2004; Doi et al.,1987). Lactate is taken up by PAO cells and converted to propionylCoA, using both poly-P and glycogen hydrolysis as energy sources. Poly-P is hydrolyzed to orthophosphate and
released from the cells, while glycogen is hydrolyzed to acetyl-CoA and CO2. Acetyl-CoA and propionyl-CoA
are reduced and condensed to form PHA, with the reducing power provided by glycogen hydrolysis. This
mechanism is compared to the situation in which acetate is used as sole carbon source in Figure 3.
A
B
Figure 3. Control of redox balance of different carbon source in PHA production under anaerobic conditions
(Mino and Satoh, 2006).
H, reducing power or hydrogen in such forms as NAD(P)H and FADH2;
S, molar amount of acetate or lactate taken up;
G, molar amount of glucose unit in glycogen consumed;
P, molar amount of monomeric units of PHA produced.
In Figure 3, redox balance regulation is depicted which is the key mechanism for anaerobic carbon uptake
and hence proliferation of PAOs. Glycolysis via Embden Meyerhof pathway (EMP) and acetate oxidation
through the TCA cycle provides the required reducing power for the conversion of acetate into 3hydroxybutyrate for PHA synthesis (Figure 3A). Mino reported in this study that the ratio S/G/P will be
1:(1/6):(2/3) and 1:0:(4/9) if all reducing power is supplied by glycolysis and by the TCA cycle, respectively. In
Figure 3 B, lactate is taken up within the cell as carbon source. By this way, ratio of S/P is increased to 2. During
conversion of lactate into acetyl-CoA the reverse operation of the TCA cycle is needed to consume excess
reducing power produced.
583
�d.
Solid Retention Time (SRT) and Temperature
It is obvious from the published reports that SRT has important impact on PHA production yield for a
given organic loading rate (OLR) .Short SRT sludge acquires higher PHA production capability, hence sludge
acclimatization with a short SRT may also be preferable for PHA production purpose. This approach is
confirmed since the sludge yield under a shorter SRT is higher than that under a longer SRT. So it can be
concluded that with a short SRT can supply sufficient amount of sludge for PHA production compared to that
with a long SRT. It was found that sludge with a short SRT (3 days) could achieve PHA content about 10% more
than sludge with a long SRT (10 days) (Chua et al, 2003). However, it was reported that higher cell growth rates
resulted in a lower PHB content higher PHB yields were produced at longer SRT when the cells were growing
more slowly (Dias et al 2006). Beun et al. (2000) reported that the PHB yield per substrate and specific
productivity were almost constant when vary the SRT from 3.8 to 19.8 day. Dionisi et al. (2001) obtained a
relatively constant storage yield in a SRT range of 0.37–3 day.
Temperature also appears to be a factor that has an important impact on the PHA production. It was
reported that temperature has actually directly affected microorganism competition which is known as GAO and
PAO. In a published report, it was mentioned that a lower temperature decrease the rates of P release/uptake,
acetate uptake, PHA oxidation, growth (Brdjanovic et al., 1998). Panswad et al. (2003) found that the rate of P
release increased with increasing temperature from 20 to 35 ºC, while the rate of P uptake decreased.
Aditionally,it was reported in a study that the increase of temperature from 15 to 35 ºC result in decrease in the
yield of PHB on acetate from 0.43 to 0.072 g PHA g-1 substrate and a decrease in the specific productivity from
0.12 to 0.060 g PHA g-1 cell dry weight h-1 (Krishna and van Loosdrecht, 1999). The yield of biomass also
decreased with temperature increase. Low temperatures (between 15 and 20 ºC) allow for a less costly process
thus increasing the PHA productivity.
e.
Availibity of Electron Acceptors
Since anaerobic P release based on fermentation process, availability of electron acceptors, such as;
oxygen, nitrate and sulphate, is not desired since this will eliminate the fermentation process. For example
availability of nitrate will result in denitrification process and nitrate reduction will take place other than
fermentation process in which organic compounds are usually used as electron acceptors. Additionally, it has
been observed that aerobic P uptake is inhibited by the presence of nitrite (Kuba et al., 1996). Saito (2004) also
reported that the presence and accumulation of nitrite inhibits PAOs, thereby favoring the growth of GAOs.
Third et al. (2003) was studied the effect of dissolved oxygen concentration (DO) on PHA production. They
found that when oxygen was limited PHA yield was 0.49 g PHA g-1 substrate using acetate as sole carbon source.
They have found that PHA yield was decreased to 0.34 g PHA g-1 substrate under excess oxygen.
4. Conclusion
Polyhydroxyalkanoates (PHA) have gained major importance because of their similar properties to
conventional plastics and their complete biodegradability. PHA can be produced from renewable carbon sources,
allowing for a sustainable process for the production and use of such polymers. PHA can be synthesized by
polyphosphate-accumulating organisms (PAO) under anaerobic conditions from external carbon sources and
internal glycogen. Glycogen-accumulating organisms (GAO) are also present in EBPR systems and compete for
carbon substrates with PAO. They also cycle PHA and glycogen in a fashion similar to PAO, but GAO do not
cycle polyphosphate. Hovewer, much more effort is required in this area to increase the production of bioplastics
to successfully replace the non-degradable plastics. Thus the future of bioplastics depends on the efforts towards
fulfilling requirements of price and performance. This review shows the parameters affecting PHA production
efficiency. Process monitoring and control are important factors for achieving high productivity. Since carbon
source has a large impact on production cost of the PHA produced recent studies have been focused on reducing
its costs. Besides carbon source, some other factors such as SRT, temperature, pH, availability of electron
acceptors in the anaerobic phase are proved to have important affect on PHA production yield. It can be
concluded that, low SRT, temperature ranging between 15-25 ºC, pH above 7 can be preferable for higher PHA
production efficiency. Indeed, the main challenge regarding the bioreactor operation and control is the
development of culture selection strategies of fast growing organisms that have a high PHA storage capacity. It
can be recommended to introduce the new metabolic pathways for not only to expand the utilizable substrate
range but also enhance the current PHA yields.
584
�References
Ahn W.S., Park S.J., Lee S.Y. (2000). Production of Poly(3-hydroxybutyrate) by fed-batch culture of recombinant
Escherichia coli with a highly concentrated whey solution. Applied Environmental Microbiology 66, 3624-3627.
Bengtsson S., Werker A., Christensson M., Welander T. (2008). Production of polyhydroxyalkanoates by activated sludge
treating a paper mill wastewater. Bioresource Technology 99, 509–516.
Beun J.J., Paletta F., Van Loosdrecht M.C.M., Heijnen J.J. (2000). Stoichiometry and kinetics of poly-beta-hydroxybutyrate
metabolism in aerobic, slow growing, activated sludge cultures. Biotechnology and Bioengineering, 67, 379-389.
Bond P.L., Keller J., Blackall L.L. (1999). Anaerobic phosphate release from activated sludge with enhanced biological
phosphorus removal. A possible mechanism of intracellular pH control. Biotechnology Bioengineering 63, 507–515.
Brdjanovic D., Logemann S., Van Loosdrecht M.C.M., Hooijmans C.M., Alaerts G.J., Heijnen J.J. (1998). Influence of
temperature on biological phosphorus removal: process and molecular ecological studies. Water Research 32, 1035–1048.
Carucci A., Lindrea K., Majone M., Ramadori R. (1999). Different mechanisms for the anaerobic storage of organic
substrates and their effect on enhanced biological phosphate removal (EBPR). Water Science Technology 39, 21–28.
Cech J.S., Hartman P. (1993). Competition between polyphosphate and polysaccharide accumulating bacteria in enhanced
biological phosphate removal systems. Water Research 27, 1219–1225.
Chen G.Q., Zhang G., Park S.J., Lee S.Y. (2001) Industrial scale production of poly(3-hydroxybutyrate-co-3hydroxyhexanoate). Applied Microbiology Biotechnology 57, 50–55.
Chen Y., Randall A.A., McCue T. (2004). The efficiency of enhanced biological phosphorus removal from real wastewater
affected by different ratios of acetic to propionic acid. Water Research 38 , 27–36.
Chua A.S.M., Takabatake H., Satoh H., Mino T. (2003). Production of polyhydroxyalkanoates (PHA) by activated sludge
treating municipal wastewater: eVect of pH, sludge retention time (SRT), and acetate concentration in inXuent. Water
Research 37 , 3602–3611.
Dias J.M.L., Lemos P.C., SeraWm L.S., Oliveira C., Eiroa M., Albuquerque M.G.E., Ramos A.M., Oliveira R., Reis M.A.M.
(2006). Recent advances in polyhydroxyalkanoate production by mixed aerobic cultures: from the substrate to the Wnal
product. Macromol. Bioscience 6 , 885–906.
Dionisi D., Majone M., Papa V., Beccari M., (2004). Biodegradable polymers from organic acids by using activated sludge
enriched by aerobic periodic feeding. Biotechnology Bioengineering 85 , 569–579.
Dionisi D., Majone M., Tandoi V., Beccari M. (2001). Sequencing batch reactor: Đnfluence of periodic operation on
physiological state microbial composition and performance of activated sludge in biological wastewater treatment. Ind. Eng.
Chem. Res. 40, 5110-5119.
Dircks K., Beun J.J., Van Loosdrecht M.C.M., Heijnen J.J., Henze M. (2001). Glycogen metabolism in aerobic mixed
cultures. Biotechnology and Bioengineering. Biotechnology Bioengineering 73, 85-94.
Doi Y., Tamaki A., Kunioka M., Soga K. (1987). Production of copolyesters of 3-hydroxybutyrate and 3-hydroxyvalerate by
Alcaligenes eutrophus from butyric and pentanoic acids. Applied Microbiology Biotechnology 28, 330-334.
Fang F., Liu X., Xu J., Yu H., Li Y. (2009). Formation of aerobic granules and their PHB production at various substrate and
ammonium concentrations. Bioresource Technology 100, 59–63.
Filipe C.D.M., Daigger G.T., Grady C.P.L. (2001a). Effects of pH on the rates of aerobic metabolism of phosphateaccumulating and glycogen-accumulating organisms. Water Environmental Research 73, 213–222.
Filipe C.D.M., Daigger G.T., Grady C.P.L. (2001b). Stoichiometry and kinetics of acetate uptake under anaerobic conditions
by an enriched culture of phosphorus-accumulating organisms at different pHs. Biotechnology Bioengineering 76, 32–43.
Hong K., Leung Y.C., Kwok S.Y., Law K.H., Lo W.H., Chua H., Yu P.H. (2000). Construction of recombinant Escherichia
coli strains for polyhydroxybutyrate production using soy waste as nutrient. Applied Biochemical Biotechnology 84-86, 381390.
Jeon C.O., Park J.M. (2000). Enhanced biological phosphorus removal in a sequencing batch reactor supplied with glucose as
a sole carbon source. Water Research 34, 2160–2170.
585
�Kadouri D., Jurkevitch E., Okon Y., Castro-Sowinski S. (2005). Ecological and agricultural significance of bacterial
polyhydroxyalkanoates. Crit. Rew.Microbiology 31, 55-67.
Karahan O., Van Loosdrecht M.C.M., Orhon D. (2006). Modeling the utilization of starch by activated sludge for
simultaneous substrate storage and microbial growth Biotechnology Bioengineering 94, 43-53.
Kasemsap C., Wantawin C. (2007). Batch production of polyhydroxyalkanoate by low-polyphosphate-content activated
sludge at varying pH. Bioresource Technology 98, 1020-1027.
Krishna purchaseC., Van Loosdrecht M.C.M. (1999). Effect of temperature on storage polymers and settleability of activated
sludge. Water research 33, 2374-2382.
Kuba T., Van Loosdrecht M.C.M., Heijnen J.J. (1996). Effect of cyclic oxygen exposure on the activity of denitrifying
phosphorus removing bacteria. Water Science Technology 34, 33–40.
Lee S.Y., (1996). Plasticbacteria? Progress and prospects for polyhydroxyalkanoates production in bacteria. Tıbtech 14, 431–
438.
Lee S.Y., Choi J. (1999). Production and degradation of polyhydroxyalkanoates in waste environment. Waste Management
19, 133-139.
Lemos P.C., Serafim L.S., Santos M.M., Reis M.A.M., Santos H. (2003). Metabolic pathway for propionate utilization by
phosphorus-accumulating organisms in activated sludge: C-13 labeling and in vivo nuclear magnetic resonance. Applied
Environmental Microbiology 69, 241–251.
Liu W.T., Mino T., Nakamura K., Matsuo T. (1996). Glycogen accumulating population and its anaerobic substrate uptake in
anaerobic-aerobic activated sludge without biological phosphorus removal. Water Research 30, 75-82.
Mino T. and Satoh H. (2006). A metagenomic sequencing effort sheds light on the biology of wastewater treatment. Nature
Bıotechnology. 24, 1229-1230.
Oehmen A., Lemos P.C., Carvalho G., Yuan Z., Keller J., Blackall L.L., Reis M.A.M. (2007). Advances in enhanced
biological phosphorus removal: From micro to macro scale. Water Research 41, 2271 – 2300.
Oehmen A., Yuan Z., Blackall L.L., Keller J. (2004a). Short-term effects of carbon source on the competition of
polyphosphate accumulating organisms and glycogen accumulating organisms. Water Science Technology 50, 139–144.
Oehmen A., Yuan Z., Zeng R.J., Keller J. (2004b). The performance of enhanced biological phosphorus removal systems
enriched with different volatile fatty acids. 2nd Young Researchers Conference. Wageningen. The Netherlands. Wageningen:
International Water Association.
Panswad T., Doungchai A., Anotai J. (2003). Temperature effect on microbial community of enhanced biological phosphorus
removal system. Water Research 37, 409–415.
Pijuan M., Saunders A.M.,Guisasola A., Baeza J.A., Casas C., Blackall L.L. (2004). Enhanced biological phosphorus
removal in a sequencing batch reactor using propionate as the sole carbon source. Biotechnology Bioeng 85, 56–67.
Quillaguaman J., Munoz M., Mattiasson B., Hatti-Kaul R. (2007). Optimizing conditions for poly(beta-hydroxybutyrate)
production by Halomonas boliviensis LC1 in batch culture with sucrose as carbon source. Applied Microbiology
Biotechnololy 74, 981-986.
Reddy C.S.K., Ghai R., Rashmi, Kalia V.C. (2003). Polyhydroxyalkanoates: an overview. Bioresource Technology 87, 137–
146.
Rhu D.H., Lee W.H., Kim J.Y., Choi E. (2003). Polyhydroxyalkanoate (PHA) production from waste. Water Science
Technology 48, 221-228.
Saito T., Brdjanovic D., Van Loosdrecht M.C.M. (2004). Effect of nitrite on phosphate uptake by phosphate accumulating
organisms. Water Research 38, 3760–3768.
Satoh H., Mino T., Matsuo T. (1992). Uptake of organic substrates and accumulation of polyhydroxyalkanoates linked with
glycolysis of intracellular carbohydrates under anaerobic conditions in the biological excess phosphate removal processes.
Water Science Technology 26, 933–942.
Satoh H., Mino T., Matsuo T. (1994). Deterioration of enhanced biological phosphorus removal by the domination of
microorganisms without polyphosphate accumulation. Water Science Technology 30, 203–211.
586
�Satoh H., Ramey W.D., Koch F.A., Oldham W.K., Mino T., Matsuo T. (1996). Anaerobic substrate uptake by the enhanced
mbiological phosphorus removal activated sludge treating real sewage. Water Science Technology 34, 9–16.
Serafim L.S., Lemos P.C., Oliveira R., Reis M.A.M. (2004). Optimization of polyhydroxybutyrate production by mixed
cultures submitted to aerobic dynamic feeding conditions. Biotechnology and Bioengineering 87, 145–160.
Seviour R.J., Mino T., Onuki M. (2003). The microbiology of biological phosphorus removal in activated sludge systems.
FEMS Microbiology Rev. 27, 99–127.
Smolders G.J.F., Vandermeij J., Vanloosdrecht M.C.M., Heijnen J.J. (1994). Model of the anaerobic metabolism of the
biological phosphorus removal process-stoichiometry and pH influence. Biotechnology Bioengineering 43, 461–470.
Sudesh K., Abe H., Doi Y. (2000). Synthesis, structure and properties of polyhydroxyalkanoates: biological polyesters. Prog.
Polym. Sci. 25, 1503–1555.
Tasli R., Artan N., Orhon D. (1997). The influence of different substrates on enhanced biological phosphorus removal in a
sequencing batch reactor. Water Science Technology 35, 75–80.
Third, K., Newland, M., Cord-ruwısch, R. (2003). The effect of dissolved oxygen in PHB accumulation in activated sludge
cultures. Biotechnology and Bioengineering 82, 238-250.
Thomas M, Wright P, Blackall L, Urbain V, Keller J. (2003). Optimisation of Noosa BNR plant to improve performance and
reduce operating costs. Water Science Technology 47,141–148.
Wang N.D., Peng J., Hill G. (2002). Biochemical model of glucose induced enhanced biological phosphorus removal under
anaerobic condition. Water Research 36, 49–58.
Wong H.H., Lee S.Y. (1998). Poly-(3-hydroxybutyrate) production from whey by high-density cultivation of recombinant
Escherichia coli. Applied Microbiology Biotechnology 50, 30-33.
587
�
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604
Title
A name given to the resource
Parameters Affecting Polyhydroxyalkanoate Synthesis from Wastewaters
Author
Author
Cırık, Kevser
Aydoğmus, Dilek Aydoğmus
Özdemir, Sebnem
Gezginci, Mehmet
Çınar, Özer
Abstract
A summary of the resource.
Plastics used almost every manufacturing industry are resist to biodegradation. Their persistence in soil for a long time has become a major concern in terms of the environment. This promotes many investigators to search for replacement of non-biodegradable by degradable plastics. Polyhydroxyalkanoates (PHAs), known as a biodegradable plastic produced by bacteria, have received increasing attention due to the difficulties in disposal of plastics. In recent years, researchers have focused on the processes to increase PHA production which involve in biological phosphorus removal (BPR). Normally, BPR can be achieved through anaerobic- aerobic cycling by a group of bacteria known as polyphosphateaccumulating organisms (PAOs). PHA is stored within the PAO as carbon polymers under anaerobic conditions by taking up volatile fatty acids (VFAs), further it is used as energy source and phosphorus uptake under aerobic conditions. The aim of this review is to discuss recent advances in PHA production from wastewaters and parameters effecting PHA production efficiency.
Date
A point or period of time associated with an event in the lifecycle of the resource
2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
Q Science (General)
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https://omeka.ibu.edu.ba/files/original/d89cb4727472f79d23272328601741b6.pdf
e22a26229ac27b75a609a4bfbf35d5dc
PDF Text
Text
Membrane Biofilm Reactors (MBfRs) for DrinkingWater Treatment
Kevser Cırık
Suleyman Demirel University, Dept. of Environmental
Engineering, Isparta, Turkey
kewss_@hotmail.com
Emine Çutay
Kahramanmaraş Sütçü Đmam University, Dept. of
Bioengineering, Kahramanmaraş, Turkey
chalon_e@hotmail.com
Elif Gamze Gündoğan
Kahramanmaraş Sütçü Đmam University, Dept. of
Bioengineering, Kahramanmaraş, Turkey
elifgamze_gundogan@hotmail.com
Arzu Kılıç
Kahramanmaraş Sütçü Đmam University, Dept. of
Bioengineering, Kahramanmaraş, Turkey
arzukilic38@hotmail.com
Özer Çınar
Kahramanmaraş Sütçü Đmam University, Dept. of
Environmental Engineering, Kahramanmaraş, Turkey
ocinar@alumni.clemson.edu
Abstract: Increase demand on water resources make ground waters essential due to the fact
that surface waters don’t actually meet the water requirements for agricultural, industrial,
recreational and drinking purposes. Provided that their quality and quantity are ensured, ground
waters are a good source as drinking waters. However, they are threatened by various micro
compounds coming from industrial, municipal, and agricultural activities such as; perchlorate,
chlorinated solvents, oxidized contaminants, and heavy metals. Therefore a reliable treatment
method should be applied to remove these micropollutants. Among the treatment technologies
used for water supply, biological methods are widely used for the treatment purposes of
drinking waters. Recent studies focus on the removal of micro pollutants by using membrane
biofilm reactors (MBfRs) which allow gaseous substrate to move across the membrane for gas
delivery and support biofilm formation on the outer surface of the membrane. This paper
reviews several applications of MBfRs for water treatment.
• Introduction
Increase in population and developments in industrialization have resulted in higher use of chemicals leading to
faster transport rates between environmental compartments such as ground waters which drinking water is
mainly produced. So many pollutants are known as danger for ground waters even if in micro levels such as;
oxidized pollutants, chlorinated solvents, heavy metals and pesticides (Nerenberg and Rittmann, 2004; Modin et
al., 2008; Chung and Ritmann, 2008). These pollutants are mainly the reason for industrial, municipal, and
agricultural activities. In this respect, increasing chemical pressure on drinking water sources should be taken
into account especially to be able to meet drinking water needs. Thus, due to the harmful effect on human health,
the contamination of drinking water sources with inorganic compounds is a matter of concern. Therefore a
reliable treatment method should be applied to remove these contaminants. Technologies available for the
treatment of contaminated ground waters include physical, chemical and biological processes. Application of
chemical and physical methods has been some disadvantages due to the toxic characteristics of these
contaminants that needs to transform less toxic forms (Modin et al., 2008; Xia et al., 2009). But by the help of
chemical and physical methods, these contaminants can only be transformed other toxic forms or even more
805
�toxic. Applied chemical and physical methods includes; ion exchange, reverse osmosis, adsorption, and electro
dialysis or more than one of them. However; biological treatment methods have the advantages of being
relatively inexpensive and having the ability to completely destroy the contaminants rather than producing
another waste. Biological treatment has long been known as a promising technology that use microorganism to
remove any pollutant. Biological processes are classified as attached or suspended growth has been the most
popular treatment configuration. In attached growth processes normally occur between microorganisms and a
surface that allow microorganism to make biofilm (Hasar, 2009). Membrane biofilm reactors (MBfRs) are
among the attached growth biological treatment applications which are newly adapted technologies that allow
biofilm growing on the membrane. This configuration of the MBfR allows gaseous substrate to move across the
membrane for gas delivery and support biofilm formation on the outer surface of the membrane. This exciting
new technology for removal of contaminants from ground waters has been among the most promising trends.
Therefore, to be able to operate the membrane biofilm reactors, system configurations, applications and also
limitation of MBfRs should deeply investigated. These factors will briefly be discussed in subsequent sections.
• Main MBfR components
MBfRs are among the biological treatment technologies that let biofilm grow on the membrane fiber
where pressurized gas diffuses through the membrane lumen in order to oxidize or reduce the soluble
constituents present outside the membrane lumen. The main difference between the membrane biofilm reactors
(MBRs) and MBfRs are that MBRs are only functional to separate biomass from effluent water, be sort of
clarifier (Nerenberg, 2004). Nevertheless; in MBfRs, membranes let naturally- forming biofilm that catalyzes
desired reactions. A gaseous substrate is also essential for this treatment technology. Depending on the treatment
aims; air, oxygen, hydrogen or methane can be used as gas. Thus a gas and a membrane that allows
microorganism accumulation represent the MBfR’s main components. The main advantages in use of MBfR for
the ground water treatment purposes are that contaminants available in these waters are mostly micro levels with
toxic properties and they cannot be removed with conventional biological treatment methods. Also, biological
treatment occurs with biochemical reactions in which a substrate acts commonly an electron donor for
microorganisms. However, ground waters are lack of electron donors essential for the treatment purposes; usage
of gases electron donors and its efficiency make MBfRs solve these problems.
•
Membranes
Membranes are one of the indispensable components in MBfRs. Membranes can be made of organic and
inorganic materials. Sheet or hollow-fiber geometries are generally applied for membrane design in which
hollow-fiber membranes are commonly used.
(A)
(B)
Figure 1. (A) A bundle of hollow-fiber membranes; (B) Cutaway view of one fiber (Ritmann, 2006)
A schematic bundle of hollow fiber and a cutaway view of one fiber are represented in Figure 1. This membrane
type has very small diameter as small as 0, 1 mm and consist of large number of membranes in a module.
Materials used for hollow-fiber membranes are usually made of hydrophobic materials in order to keep their
806
�pores dry and thus make gaseous molecules diffuse much more quickly through dry pores. By this way,
efficiency of the gaseous distribution can be maintained. Dry pores also eliminate the fiber clogging from liquid
and biofilm infiltration. In Figure 2, scanning electron micrograph of pore structure on the hollow fiber
membrane is depicted.
Figure 2. Pore structure on the hollow fiber membrane (Nerenberg, 2005)
•
Biofilm
Biofilms are formed on the membrane surface naturally. They are the accumulated and attached
microorganisms and are responsible for the removal of the contaminants in the effluent. Normally biofilm-based
treatment methods supply both electron donor and/or acceptor for biofilm formation from the bulk solution via
diffusion. But the mechanism in MBfRs is rather different since electron donor, which is normally a gaseous
substrate, is diffused into the biofilm from the membrane and other from the bulk liquid.
Figure 3. Biofilm microorganisms from MBfR (Xia et al., 2009)
Figure 3 indicates the surface morphology of the hollow fiber with biofilm formation. Actually biofilm
formation is a key factor to be control since it directly affects the MBfR efficiency. It has been reported that
biofilm structure such as; thickness, density and composition is vital for MBfRs. For instance, excess biofilm
development is undesirable because of the fact that it can result in biofilm sloughing, non-uniform flow
distribution, inhibition of substrate or gas diffusion. The detachment or sloughing of biomass needs to be balanced
with biomass accumulation (Hwang et al., 2009). Hence, many researchers identified biofilm control as one of the
most challenging aspect of MBfR operation (Hwang et al.,2009; Celmer et al., 2008).
•
Gas substrate
Mostly biological treatment processes are based on oxidation reduction reactions. In MBfR technologies
microorganisms use electron donors as an electron and energy source. Electrons released from electron donors
807
�(normally H2) are transfer to the electron accepting contaminants. The few rate of these electrons are used for
microbial growth and hence biofilm formation on the surface of membrane. The most known advantage of the
MBfR technology is the use of a gaseous substrate which prevents regrowth caused by organic donor materials
used as electron donors such as ethanol, methanol, and acetate. Published reports have been showed that organic
materials used for electron donor results in recontamination of waters by residual of these organic donors. By
this respect, substrate as gaseous form is usually used as electron donor but some cases as electron acceptor. For
the electron donor purposes, methane, hydrogen and for the electron acceptor purposes oxygen has been mostly
used in recent studies (Nerenberg, 2005).
Hydrogen is the ideal electron donor that has been used in most MBfR studies due to the inherent
advantages over other organic donors. H2 is non toxic to human and cost effective. Supporting autotrophic
bacteria eliminates the need for an organic carbon source since the growth rate of autotrophic bacteria is slow;
amount of produced microorganism per removed substrate is rather scarce. So H2 produces far less excess
biomass than organic donors. On the other hand, its low water solubility prevent the residual in the water which
means it cannot be over-dosed to increase effluent BOD and be wasted at the same time (Ritmann, 2006).
Additionally, it was reported in a study that use of H2 as gaseous substrate reduce the cost about 3-15 times
compaired to other common organic donors used (Lee and Rittmann,2000).
(B)
10.
Figure 4. (A) Normal biofilm and (B) MBfR biofilm; The bold line is the dissolved gas concentration, while
the dotted line is the substrate from the bulk liquid (Nerenberg, 2005).
Figure 4 compares the ways in order to supply gas (electron donor) into the bulk solution and represents
the advantages and disadvantages of these ways. Normal biofilm and biofilm formed on the MBfR have the
dissimilarities with respect to gas diffusion. The amount of required electron donor is much less in MBfRs
compare to the conventional biofilms. This promotes the usage of the membrane biofilm reactors especially for
the cost-effectiveness of the process.
• MBfR applications
This part of the review paper includes research articles mainly focusing on MBfR applications. Besides
drinking water treatment processes, there are applications of MBfRs for industrial and domestic wastewater
treatments. Researches on the applications of MBfRs have been focused on the denitrification processes and the
treatment of oxidized contaminants (Nerenberg et al., 2002; Chung et al., 2006).
Removal of nitrogen
Nitrate contamination is a widespread problem for drinking water around the world. Nitrogen is mainly
found in ground waters as mainly in the form of nitrate (
) and nitrite (
). Contamination of ground
waters with nitrate mainly the reason for the usage of nitrogen fertilizers and the irrigation with domestic
wastewater (M. Shrimali, K.P. Singh,2001). Nitrate should be regulated in drinking water since the excess levels
can cause methemologlobinemia or blue baby disease in humans. Nitrate removal in biological systems involves
denitrification processes which require anaerobic conditions. Denitrification occurs in two ways according to the
carbon source, heterotrophic and autotrophic; respectively. In heterotrophic denitrification processes, electron
808
�donor source is normally organic compounds. However, due to a very low organic carbon sources in ground
waters nitrate cannot be removed effectively through heterotrophic biological methods. Hopefully, autotrophic
denitrification has advantages over the heterotrophic denitrification, such as usage of inorganic electron donor
which makes biomass yields low (Shin et al., 2007). In a research article it has been found that denitrification
rate can be affected from gas pressure and nitrate loading (Celmer et al., 2006).
The reactions involved in autotrophic denitrification consist of oxidation of H2 gas to hydrogen ions and
reduction of nitrate to nitrogen gas. Overall half reactions and the schematic diagram of the MBfR for
denitrification process are represented in Figure 5.
Oxidation of hydrogen gas :
Reduction of nitrate:
Overall denitrification reaction:
Figure 5. Principle schematic diagram of MBfRs for autotrophic denitrification and reactions involved (Xia et
al., 2009)
•
Removal of micro contaminants
Hydrogen-based MBfR is a successful tool of reducing many oxidized pollutions such as such as;
arsenate (AsO43−), perchlorate (ClO4−), selenate (SeO42−), chromate (CrO4−), trichloroethene (TCE), and
nitrosodimethylamine (NDMA), hexavalent chromium which are difficult to remove in conventional biological
treatments (Ergas and Reuss, 2001; Lee and Rittmann, 2002; Nerenberg et al., 2002). These contaminants are
usually found in micro levels in ground waters. Origin of the perchlorate in water mainly is the improperly
disposed-of rocket fuel. It inhibits thyroid function even if at low levels (Espenson, 2000). Level of 4 µg/L has
been determined in California for perchlorate in spite of the fact that there is no standard for perchlorate. Arsenic
is another micro pollutant exclusively found in groundwater which can cause gastrointestinal damage and
cardiac damage. Hence it has been considered as a human carcinogen. Level of 10 µg/L arsenic is determined by
Protection Agency (EPA) Maximum Contaminant Level Goal (MCLG). Bromate is regulated under the Stage 1
Disinfectants/Disinfection By-Products Rule at 10 µg/L (Kirisits et al., 2001). Chromium is also an inorganic
contaminant. It is released to drinking water sources from electroplating facilities, old mining operations, and
fossil-fuel power plants. It has been known that chromium can cause liver and kidney damage, and the maximum
contaminant level for drinking water is 0.1 mg/L total chromium. DCM (CH2Cl2), methylene chloride, which is
carcinogenic, highly soluble in water, and one of the most common groundwater contaminant (Kohlerstaub et al.,
1995). Consequently, these micro contaminants should be removed due to their adverse affects. In a published
report, it has been found that a wide range of oxidized contaminants (arsenate, perchlorate, selenate, chromate,
and dichloromethane) can be successfully removed by the hydrogen based hallow-fiber membrane biofilm
reactor and removals were greater than 75% without any community adaptation. It has been noted that when the
contaminants need to be reduced to very low levels nitrate or oxygen can serve as primary electron acceptors, on
the other hand; many of the contaminants can serve as primarily electron acceptors at higher concentrations.
(Nerenberg and Rittmann, 2004).
Conclusion
MBfR is a novel system that uses membranes to supply dissolved gaseous directly without bubbling to a
biofilm growing on the membrane surface. The H2-based MBfR has great potential to solve emerging problems
in water quality and has kept increasing since it appears in the early 1980s. Especially after 2000, more research
809
�studies have been published from all around the world. MBfR is a promising technology by the means of
gaseous substrate usage, which prevents regrowth caused by organic donor materials used as electron donors. By
utilizing H2 gas as the electron donor, some of the major problems such as; a large increase in excess biomass
generation, over- or under-dosing of donor, safety concerns can be able to be solved. Application studies of
MBfRs have shown promising potential and suggest the possibility of utilizing MBfR in biological treatment
technologies also for industrial and domestic wastewater treatments but mainly for the purpose of removing
micro pollutants found in ground waters. The results of the published reports confirm that the wide variety of
oxidized contaminants can be successfully reduced and removed immediately in a hydrogen-oxidizing MBfR
with oxygen or nitrate as primary acceptors. However, so many research articles has emphasized that there are
some outstanding challenges associated with MBfRs in the near-future. The principal obstacle to full scale
implementation is the problem of excess biomass control which can lead to significant performance deterioration.
Hence, field studies are needed to focus on biofilm thickness and activity control to make commercial scale
applications feasible. Additionally, possible developments in this area are likely to focus on membrane material
and module design improvements in along with selection of appropriate liquid/gas scouring methodologies.
References
Celmer, D.,Oleszkiewicz, J.,Cicek,N.(2008).Impact of shear force on the biofilm structure and performance of a membrane
biofilm reactor for tertiary hydrogen-driven denitrification of municipal wastewater:Water Research ,42 3057 – 3065.
Celmer, D.,Oleszkiewicz, J.,Cicek,N.,Husain H.(2006).Hydrogen limitation- a method for controlling the performance of
membrane biofilm reactor for autotrophic denitrification of wastewater: Water Science and Technology, 54(9), 165 – 172.
Chung, J.,Brown,R.,Rittmann B.E.(2008).Bioreduction of trichloroethene using a hydrogen – based membrane biofilm
reactor : Environmental science & Technology 47, 477 – 483.
Ergas, S.J. and Reuss, A.F. (2001). Hydrogenotrophic denitrification of drinking water using a hollow fibre membrane
bioreactor. Journal of Water Supply Research and Technology – Aqua, 50(3), 161–171.
Espenson, J. (2000). The problem and perversity of perchlorate. Perchlorate in the Environment, 1–9.
Hasar ,H.,Đpek,U.(2010). Gas permeable - membrane for hydrogenotropic denitrification:Clean 2010, 38(1) 23 – 26.
Hwang ,J.H.,Cicek,N.,Oleszkiewicz,J.A.(2009).Membrane biofilm reactors for nitrogen removal: state-of the art and research
needs: Water Science and Technology , 2739 – 2747.
Kirisits, M.J., Snoeyink, V.L., Inan, H., Chee-Sanford, J.C., Raskin, L. and Brown, J.C. (2001). Water quality factors
affecting bromate removal in biologically active carbon filters. Water Research, 35(4),891–900.
Kohlerstaub, D., Frank, S. and Leisinger, T. (1995). Dichloromethane as the sole carbon source for Hyphomicrobium sp
strain Dm2 under denitrification conditions. Biodegradation, 6(3), 229–235.
Lee, K.-C. and Rittmann, B.E. (2002). Applying a novel autohydrogenotrophic hollow-fiber membrane biofilm reactor for
denitrification of drinking water. Water Research, 36(8), 2040–2052.
Modin, O.,Fukushi, K.,Yamamoto, K.(2008).Simultaneous removal of nitrate and pesticides from groundwater using a
methane – fed membrane biofilm reactor :Water Science and Technology ,58.6.
Nerenberg, N.(2005).Membrane Biofilm Reactors for Water and Wastewater 2005 Borchardt Conference: A Seminar on
Advances in Water and Wastewater Treatment.
Nerenberg, R., Rittmann, B.E. and Najm, I. (2002). Perchlorate reduction in a hydrogen-based membranebiofilm reactor. J.
AWWA, 94(11), 103–114.
Nerenberg, R.,&Rittmann B.E.(2004).Hydrogen–based,hollow– fiber membrane biofilm reactor for reduction of perchlorate
and other oxidized contaminants:Water Science and Technology ,223 – 230.
Rittman, B.E.(2006).The membrane biofilm reactor : the natural partnership of membranes and biofilm : Water Science and
Technology ,53(3),219 – 225.
Shin,J.,Sang,B.,Chung,Y.,Choung,Y.(2007).A novel CSTR- type of hollow fiber membrane biofilm reactor for consecutive
nitrification and denitrification:Desalination 221,521 – 533.
Treatment A Seminar on Advances in Water and Wastewater Treatment, Ann Arbor, MI 574-631-4098.
810
�
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Title
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Membrane Biofilm Reactors (MBfRs) for DrinkingWater Treatment
Author
Author
Cırık, Kevser
Çutay, Emine
Gündoğan, Elif Gamze
Kılıç, Arzu
Çınar, Özer
Abstract
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Increase demand on water resources make ground waters essential due to the fact that surface waters don’t actually meet the water requirements for agricultural, industrial, recreational and drinking purposes. Provided that their quality and quantity are ensured, ground waters are a good source as drinking waters. However, they are threatened by various micro compounds coming from industrial, municipal, and agricultural activities such as; perchlorate, chlorinated solvents, oxidized contaminants, and heavy metals. Therefore a reliable treatment method should be applied to remove these micropollutants. Among the treatment technologies used for water supply, biological methods are widely used for the treatment purposes of drinking waters. Recent studies focus on the removal of micro pollutants by using membrane biofilm reactors (MBfRs) which allow gaseous substrate to move across the membrane for gas delivery and support biofilm formation on the outer surface of the membrane. This paper reviews several applications of MBfRs for water treatment.
Date
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2010-06
Keywords
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Conference or Workshop Item
PeerReviewed
Q Science (General)
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https://omeka.ibu.edu.ba/files/original/cc524d044878f83b391a100c1ca39ee8.pdf
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Text
Parameters Affecting Anaerobic Color Removal of Textile Wastewaters:
An Overview
Kevser Cırık
Suleyman Demirel University, Dept. of Environmental Engineering, Isparta, Turkey
kewss_@hotmail.com
Özer Çınar
Kahramanmaraş Sütçü Đmam University, Dept. of Environmental Engineering, Kahramanmaraş, Turkey
ocinar@alumni.clemson.edu
Abstract: Release of colored wastewaters represents a major environmental problem
worldwide due to the toxicity, mutagenicity and carcinogenicity of the dyes and their
breakdown products. Therefore much attention has been focused on the effective treatment of
dyes discharged from the dying and textile industries. The most widely used dyes in industries
are azo dyes which require anaerobic and aerobic phases for their complete biodegradation.
Color is removed under anaerobic conditions in which azo dyes act an electron acceptor.
Further, aerobic conditions are essential for removal of breakdown products which are known
resist to biodegradation under anaerobic conditions. Thus using both anaerobic and aerobic
stages represents both decolorization and mineralization of azo dyes. Anaerobic stage is the
first and the most important phase for color removal, however; decolorization can be affected
by so many parameters such as; organic carbon source added, microorganisms selected, dye
structure, cycle time, sludge age, and alternative electron acceptors involved. This review
article summarizes the results of several research studies dealing with the factors affecting
anaerobic color removal efficiency.
Introduction
Increased population and developments in industrialization have resulted in higher use of textile products
leading to release of its huge amount of wastewaters to the environment. Actually the main problem related to
the textile wastewaters is colored effluents. There are so many types of dyestuffs used in textile industry to give
its color to the fabrics Dye is the most difficult constituent of the textile wastewater to treat since they are
synthetic and typically derived from coal tar and petroleum based intermediates. It is estimated that almost 109
kg of dyes are produced annually in the word, of which azo dyes represent about 70% by weight (Dos Santos et
al., 2007). Azo dyes are characterized by nitrogen to nitrogen double bonds (N=N). The major problem
associated with the dyes and their breakdown products is their toxicity, mutagenicity and carcinogenicity. Their
discharge into surface water leads to aesthetic problems and adversely affecting to aquatic life. To overcome this
problem, much attention has been focused on the effective treatment of dyes discharged from the dying and
textile industries. There are many reports on the use of chemical and physical methods for color removal
(Cooper, 1993; Hao et al., 2000; Dos Santos et al., 2007). The most commonly used chemical and physical
treatment methods for dye-containing textile-processing wastewaters are chemical oxidation, chemical
flocculation and settling, adsorption, membrane filtration and ion exchange. By these existing physical and
chemical color removal methods, color is generally concentrated in the sludge or colored molecules are partly
removed. Moreover, formation of large amounts of sludge and economical limitations presents disadvantages of
these methods. Alternatively, biological methods are commonly considered to be the most effective treatment
applications since they present lower operating costs and improved applicability (Shaw et al., 2002; Lourenço et
al., 2001).
It is known that several microorganisms; such as fungi, bacteria and algae; can decolorize many azo dyes
(Pandey et al., 2007). In this review we will focus on the bacterial decolorization. Bacterial decolorization
applied for textile effluents are based on anaerobic and aerobic treatment. Under anaerobic conditions, azo dyes
are readily cleaved generating aromatic amines. The required electrons are provided by electron donating carbon
sources which can be glucose, acetate, volatile fatty acids (VFAs). Hence, azo dye acts as electron acceptor and
organic matters act as electron donor under anaerobic conditions. Electrons released from oxidation of electron
donor directly accepted by azo dyes which results in azo linkage and color removal. Although these process the
571
�remove color of the wide range of azo dyes dyes, they do not completely mineralize the aromatic amines generated
in the anaerobic environment with few exceptions (Brown and Laboureur, 1983). However due to the carcinogenic
effects treatment of the aromatic amines is essential. It is known that some of the aromatic amines can be biodegraded
under aerobic conditions (Brown and Hamburger 1987; Seshadri et al. 1994; Carliell et al. 1995). Combination of
anaerobic and aerobic conditions is therefore the most convenient concept for treating colored wastewaters (Haug et al.,
1991; Zaoyan et al., 1992; Seshadri et al., 1994; Kudlich et al., 1996; Hu, 1998).
This review article summarizes the results of several research studies dealing with combined anaerobic-aerobic
SBRs. Since anaerobic stage is the first and the most important phase for color removal, parameters affecting color
removal should be determined to achieve desirable treatment. Therefore, this review study especially presents the
problems dealing with anaerobic color removal. Anaerobic color removal can be affected by so many parameters such
as; organic carbon source added, microorganisms selected, dye structure, cycle time, sludge age, and alternative
electron acceptors involved. Therefore, factors affecting anaerobic color removal efficiency are briefly discussed in
subsequent sections.
Factors Affecting Anaerobic Color Removal Efficiency
As mentioned before, anaerobic phase is the first stage of decolorization process starting with the
formation of intermediary aromatic amines by reductive cleavage of the azo bond (Walker 1970; Wuhrmann et
al., 1980; Haug et al., 1991; Blumel et al., 1998). The schematic diagram of enzymatic dye reduction is depicted
in Figure 1. The research papers reviewed are proved that color removal is mainly associated with the anaerobic
stage of the SBR, however; contribution of aerobic stage is almost none. Therefore, this review study especially
presents the problems dealing with anaerobic phase of SBRs. Since most of the azo dyes can be decolorized
under anaerobic conditions, anaerobic biodegradation seems to be nonspecific. Nevertheless; decolorization can
be affected by so many parameters such as; organic carbon source added, microorganisms selected, dye structure,
cycle time, sludge age, and alternative electron acceptors involved. Therefore, factors affecting anaerobic color
removal efficiency are briefly discussed in subsequent sections.
Figure 1. Enzymatic azo dye reduction, adapted from Subst., substrate or primary electron donor;
Subst.oxid, products of substrate oxidation (Dos Santos et al., 2007)
Microorganism
In most of the reported processes of azo dye biodegradation, a wide range of organisms are found to
reduce azo compounds such as bacteria, algae, and fungi. Azo dyes are generally known to resist aerobic
bacterial biodegradation with the exception of bacteria with specialized azo dye reducing enzymes. Bacterial
strains which can anerobically reduce azo dyes, cannot utilize dye as the growth substrate, therefore; require
organic carbon sources. There are only a few bacteria that are able to grow on azo dyes as the sole carbon source.
Aromatic amines resulting from reductive cleavage of azo bond can be used as a carbon and energy source for
bacterial growth. Like carbon source, a nitrogen source is also essential for decolorization process with exception
of bacteria that can be used azo dyes as a nitrogen source. As reported before, ammonium chloride is the most
suitable among all nitrogen sources for SBR studies, since nitrate is believed that it is a better electron acceptor
than azo bond (Wang et al., 2008). Based on the previous publications, azo dye can be reduced by azoreductasecatalyzed reduction under anaerobic conditions. But still there is a speculation whether bacterial flavin
reductases are responsible for the azo reductase activity observed with bacterial cell extracts. In a published
report, it was reported that flavin reductases are indeed able to act as azo reductases (Russ et al., 2000). Bacteria
produce extracellular oxidative enzymes which are relatively non-specific enzymes catalyzing the oxidation of a
variety of dyes. It was reported that there are so many diverse groups of bacteria playing role in decolorization. It
has been also reported that mixed microbial community could reduce various azo dyes and members of the γproteabacteria and sulfate reducing bacteria (SRB) were found to prominent members of mixed bacterial
population by using molecular methods to determine the microbial population dynamics (Pandey et al., 2007).
572
�Dye Structure
It appears that almost every azo compound that has been tested is biologically reduced under anaerobic
conditions, nevertheless; though similar conditions were provided, different color removal efficiencies were
achieved. This indicates that, dye structure is important when investigating biological color removal by SBRs. It
was reported that metal-ion containing dyes can have adverse effect on decolorization efficiency (Chung et al.,
1978; Brown and De Vito 1993). It has been also reported that azo compounds with methyl, methoxy, sulpho or
nitro groups being less likely to biodegrade than the others with a hydroxyl or amino group (Zimmermann et al.,
1982; Claus et al., 2002). Azo dyes with a limited membrane permeability such as; sulfonated azo dyes, cannot
be reduced by intracellularly (Stolz, 2001).
Cycle Time
Though cycle time plays an important role in the SBR for the decolorization process, not so many reports
are found in literature. The long retention times are often applied in the anaerobic phase of the reactor studies
such as 18h, 21h. In several studies, it was reported that there is a positive correlation between the anaerobic
cycle time and color removal (Kapdan et al., 2003; Albuquerque et al., 2005). Indeed, in combined anaerobicaerobic SBRs, since bacteria shifted from aerobic to anaerobic conditions, or vice versa; anaerobic azo reductase
enzyme can be adversely affected from aerobic conditions which are essential for aromatic amine removal,
thereby resulting in insufficient color removal rate. To investigate the effect of cycle time on biodegradation of
azo dyes, Çınar et al. (2008) operated SBR in three different total cycle times (48-h, 24-h and 12-h), fed with a
synthetic textile wastewater. The results indicated that decrease in anaerobic cycle time, the system performance
on color removal is not adversely affected; on the contrary, both color removal efficiency and COD removal
efficiency are slightly improved.
Sludge Age
The sludge retention time (SRT) is known as very important operational parameter for color removal in
SBR system. To obtain efficient color removal rate, adequate microbial population is desired. It was reported
that 10 days sludge retention time remained insufficient to obtain adequate population, and to ensure the color
removal, sludge retention time was increased to 15 day (Lourenço et al., 2001).
Redox Mediators
Since long retention times are often applied in the anaerobic phase of the SBR, it can be concluded that
reduction of many azo dyes is a relatively slow process. Reactor studies indicate that however; by using redox
mediators; which are compounds that accelerate electron transfer from a primary electron donor (co-substrate) to
a terminal electron acceptor (azo dye), azo dye reduction can be increased (Keck et al., 2002; Kudlich et al.,
1997). By this way, higher decolorization rates can be achieved in SBRs operated with a low hydraulic retention
time (HRT) (Cervantes et al., 2001; Dos Santos et al., 2003). Flavin enzyme cofactors, such as flavin adenide
dinucleotide (FAD), flavin adenide mononucleotide (FMN) and riboflavin as well as several quinone compounds
such as AQS, AQDS and lawsone have been found as redox mediators (Semde et al., 1998; Cervantes et al.,
2000; Rau et al.,2002a; Rau et al.,2002b).Though accelerating effect of redox mediators is proved, differences in
electro-chemical factors between mediator and azo dye is limiting factor for this application. It was reported that
redox mediator applied for biological azo dye reduction must have redox potential between the half reactions of
the azo dye and the primary electron donor (van der Zee et al., 2003). The standard redox potential for different
azo dyes is screened generally between -430 and -180 mV (Dubin and Wright 1975).
Alternative Electron Acceptors
Decolorization of azo dyes starts by reductive cleavage of azo bond. Electrons releasing from oxidation of
organic compounds in the wastewaters goes through the azo dye and cleaves the azo bond. As anaerobic color
removal occurs by the way of reduction of the azo dye which acts a final electron acceptor in the microbial
electron transport chain, existing different electron acceptors in anaerobic zone can be assessed as limiting factor
for the dye removal. Alternative electron acceptors such as oxygen, nitrate, sulfate and ferric ion; may compete
with the azo dye for reducing equivalents, and resulting in insufficient color removals under anaerobic
conditions. Electron flow preference as a function of the different electron couples is depicted in Figure 2. Among the
electron acceptors involved in electron transport chain, oxygen is the most effective electron acceptor. Anaerobic
reactors in full-scale treatment systems are designed as open to the atmosphere. The effect of oxygen entering
anaerobic reactors through the surface is generally assumed to be negligible since surface area is small relative to
573
�the reactor volume. Oxygen can get into the anaerobic reactors of waste water treatment plants with the mixed
liquor recirculated from the aerobic zone and mixing. The impact of oxygen on anaerobic color removal
efficiency becomes progressively larger when it is thought that oxygen is the most effective electron acceptor on
the electron transport chain. Researchers have reported that decolorization is significantly affected from the,
high-redox-potential electron acceptor, dissolved oxygen. This is because; released electrons by oxidation of
organic compounds are preferentially used to reduce oxygen rather than the azo dye. Oxygen has an adverse
effect on decolorization under anaerobic conditions, therefore; facultative or obligate anaerobes are necessary for
azo dye reduction (Chang and Kuo, 2000). Inhibition of azo reductase activity by oxygen was also reported for
Pseudomonas luteola (Chung and Stevens, 1993; Blumel et al., 1998). Indeed, NADH leads to bacterial
biodegradation of azo dyes by acting electron donor. In the case of the fact that oxygen is the electron acceptor,
the consumption of NADH by oxidative phosphorylation can adversely affect the enzymatic decolorization of
azo dye. In a recent study results also suggested that the presence of oxygen inhibits azo decolorization when the
dissolved oxygen concentration in the medium was higher than 0.5 mg/L (Xu et al, 2007). This is mainly due to
the adverse effect of the molecular oxygen on anaerobic azo reductase enzyme.
Figure 2. Electron flow preference as a function of the different electron couples, RM and RMreduc are the
oxidized and the reduced form of the redox mediator, respectively (Dos Santos et al., 2007)
Among the electron acceptors involved in electron transport chain, nitrate is the second effective electron
acceptor. Nitrate is normally found in textile processing wastewaters and generally coming from the salts such as,
sodium nitrate which is included in dye baths for the improvement of dye fixation to the textile fibers. Nitrate
concentrations used during textile processing can reach 40–100 g/l (Carliell et al., 1998). The importance of
nitrate in anaerobic phase of SBR is that nitrate can compete with the azo dye for the reducing equivalents
formed and resulting in decreasing decolorization (Carliell et al., 1995; Carliell et al., 1998, Lourenço et al.,
2001; Panswad et al., 2000; Wuhrmann et al., 1980). Wuhrmann et al (1980) was reported that azo dye cannot be
decolorized until denitrification ends up. Like nitrate, sulfate is also a constitute of textile processing
wastewaters. Sulfate is generally added to the dye baths for ionic strength adjustment or it may be formed by the
oxidation of sulfur species used in dyeing processes, such as sulfide, hydrosulfide, and dithionite (van der Zee et
al., 2003). There are so many reports highlighting different effects of sulfate on azo dye degradation. It seems
that in the presence of sulfate, decolorization may be rather stimulated than competitively suppressed (Carliell et
al., 1995; Carliell et al., 1998; Panswad and Luangdilok, 2000; van der zee, 2003; Albuquerque et al., 2005). It
was reported that when inhibiting sulfate-reducing activity of microbial population in SBR by the addition of
molybdate, anaerobic azo dye removal efficiency is decreased. Indeed, since sulfate acts as an electron acceptor
under anaerobic conditions, may compete with the dyes for the electrons available, thus causing an adverse
effect on the decolorizing process. However; microbial population and sulfate concentration is also important for
the reactions taking place during anaerobic phase. High sulfate concentrations are found to adversely affect
decolorization unless sufficient amount of substrate is supplied to overcome the negative effects of elevated
concentrations of sulfate (Cervantes et al., 2007). Furthermore; when sulfate is reduced under these conditions
by sulfate reducing bacteria (SRB); sulfide, which is known as bulk reductant, is generated and can in turn serve
as an electron donor. Sulfide generation is found to also contribute to the reduction of azo dyes. It is also
reported that cofactors involved during microbial reduction of sulfate such as; cytochrome C3 (-205 mV) and
NADH (-324 mV); have appropriate redox potential. Therefore, can channel the electrons to azo dyes.
574
�Meanwhile, the redox potentials with more positive of the dye reduction than the redox potential of biological
sulfate reduction (-220 mV) can be accelerated by sulfate. It was also reported articles that ferric iron can act as
an electron acceptor under anaerobic conditions in which azo dye reduction occurs. Like sulfate, it was found
that addition of ferric iron to the reactor stimulates the azo dye reduction. Indeed, the reactions are dealing with
the redox couple Fe (III)/Fe (II) which can act as an electron shuttle for transferring electrons from electron
donor to the electron accepting azo dye. Meanwhile, reactions of both reduction of Fe (III) to Fe (II) and
oxidation of Fe (II) to Fe (III) facilitate the electron transport from the substrate to azo dye, thus acting as an
extracellular redox mediator (Albuquerque et al., 2005).
Primary Electron Donor Type
Since anaerobic azo dye reduction is an oxidation-reduction reaction, a liable electron donor is essential
to achieve effective color removal rates. It is known that most of the bond reductions are occurred during active
bacterial growth (Nigam et al., 1996). Therefore, anaerobic azo dye reduction is extremely depended on the type
of primary electron donor. It was reported that ethanol, glucose, H2/CO2 and formate are effective electron
donors, contrarily; acetate and other volatile fatty acids are normally known as poor electron donors (Dos Santos
et al., 2003; Tan et al., 1999; Pearce et al., 2006). So far, because of the substrate itself or microorganisms
involved, with some primary substrates better color removal rates have been obtained but with others no
effective decolorization have been observed. Electron donor concentration is also important to achieve higher
color removal rates. Since there are so many reactions involved in bioreactor, competition for reducing
equivalents by other reactions may increase the required amount of primary substrate. Though in theory the
amount of electron donor per mmol monoazo dye azo is 32 mg COD, it was reported in a study that even if 60300 times higher of the stoichiometric amount is used, more electron donor source is needed (O’Neill et al.,
2000).
Dye concentratıon
In several studies, large variations in dye concentrations have been applied in the reactor studies and it
was reported that dye concentration may play a role in the decolorization process. In the case of exceeding the
reactor’s biological azo dye reduction capacity, high dye concentration may adversely affect the dye removal
efficiency and COD removal efficiency. Kapdan and Özturk (2005) reported that increasing initial dyestuff
concentration adversely affect the COD removal performance of SBR. Nevertheless; dye removal rate may be
increased by increasing dye concentrations (Cruz and Buitron, 2001). Some of the reactor studies have been
proved the possibility of azo dye toxicity to microorganisms involved in biodegradation. Though toxicity is
related to dye concentration, dye type applied is also important (Luangdilok and Panswad 2000). Metal-complex
dyes and reactive dyes are known to have toxicity effect on decolorization process from the literature (Libra et
al., 2004).
Conclusion
Azo dye containing wastewaters seems one of the most polluted wastewaters which require efficient
decolorization and subsequent aromatic amine metabolism. Based on the available literature, it can be concluded
that anaerobic- aerobic SBR operations are quite convenient for the complete biodegradation of both azo dyes
and their breakdown products. Nevertheless, like the other methods used for biological treatment, SBRs treating
colored wastewaters have some limitations. Presence of forceful alternative electron acceptors such as nitrate and
oxygen, availability of an electron donor, microorganisms, and cycle times of anaerobic and aerobic reaction
phases can be evaluated as quite significant. Though treatment of azo dye containing wastewaters needs
combined anaerobic-aerobic phases, microorganisms are subjected to continually alternating anaerobic and
aerobic conditions. Thus, it is presumable that anaerobic enzymes involved in the azo dye reduction may be
adversely affected from aerobic conditions, as well as aerobic enzymes involved in the aromatic amine
mineralization may be adversely affected from anaerobic conditions. Since little is known about the regulations
of the enzymes involved in complete biodegradation of colored wastewaters, this approach seems to need
advanced investigation to improve color removal and aromatic amine mineralization.
References
Albuquerque MGE, Lopes AT, Serralheiro ML et al (2005) Biological sulphate reduction and redox mediator effects on azo
dye decolourisation in anaerobic–aerobic sequencing batch reactors. Enzyme and microbial technology 36: 790–799
575
�Blumel S, Contzen M, Lutz M et al (1998) Isolation of a bacterial strain with the ability to utilize the sulfonated azo
compound 4-carboxy-4`- sulfoazobenzene as the sole source of carbon and energy. Applied Microbiology and Biotechnology
64: 2315 – 2317
Brown MA, DeVito SC (1993) Predicting azo dye toxicity. Critical Reviews in Environmental Science and Technology 23:
249–324
Brown, D., Hamburger, B., (1987) The degradation of dyestuffs: part III – investigations of their ultimate degradability.
Chemosphere 16, 1539–1553.
Brown, D., Laboureur, P., (1983) The degradation of dyestuffs: part I – primary biodegradation under anaerobic conditions.
Chemosphere 12, 397–404.
Carliell CM , Barclay SJ, Naidoo N et al (1995) Microbial decolourasition of a reactive azo dye under anaerobic conditions.
Water SA 21: 61–69
Carliell CM, Barclay SJ, Shaw C et al (1998) The effect of salts used in textile dyeing on microbial decolourisation of a
reactive azo dye. Environmental technology 19: 1133–1137
Cervantes FJ, Enrıquez JE, Petatan EG et al (2007) Biogenic sulphide plays a major role on the riboflavin-mediated
decolourisation of azo dyes under sulphate-reducing conditions. Chemosphere 68: 1082–1089
Cervantes FJ, van Der Velde S, Lettinga G et al (2000) Competition between methanogenesis and quinone respiration for
ecologically important substrates in anaerobic consortia. FEMS Microbiology Ecology 34: 161–171
Cervantes FJ, van der Zee FP, Lettinga G (2001) Enhanced decolourisation of acid orange 7 in a continuous UASB reactor
with quinones as redox mediators. Water Science and Technology 44: 123–128
Chang JS, Kuo TS (2000) Kinetics of bacterial decolorization of azo dye with Escherichia coli NO3. Bioresource Technology
75:107–111
Chung KT, Stevens SEJ (1993) Degradation of azo dyes by environmental microorganisms and helminths. Environmental
Toxicology and Chemistry 12: 2121–2132
Chung KT, Fulk GE, Egan M (1978) Reduction of azo dyes by intestinal anaerobes. Applied Microbiology and
Biotechnology 35: 558–562
Claus H, Faber G, Koenig H (2002) Redox-mediated decolorization of synthetic dyes by fungal laccases. Applied
Microbiology and Biotechnology 59: 672–678
Cooper, P., (1993) Removing colour from dyehouse waste waters—a critical review of technology available. J. Soc. Dyers
Colourists 109, 97–100.
Cruz A, Buitron G, (2001) Biodegradation of disperse blue 79 using sequenced anaerobic/aerobic biofilters. Water Sci
Technol 44 (4): 159–166
Çınar Ö, Yaşar S, Kertmen M et al (2008) Effect of cycle time on biodegradation of azo dye in sequencing batch reactor.
Process Safety and Environmental Protection 86: 455–460
Dos Santos AB, Cervantes FJ, van Lier JB (2007) Review paper on current technologies for decolourisation of textile
wastewaters perspectives for anaerobic biotechnology. Bioresearc techonogy 98: 2369–2385
Dos Santos AB, Cervantes FJ, Yaya-Beas RE et al (2003) Effect of redox mediator AQDS on the decolourisation of a
reactive azo dye containing triazine group in a thermophilic anaerobic EGSB reactor. Enzyme and microbial technology 33:
942–951
Dubin P, Wright KL (1975) Reduction of azo food dyes in cultures of Proteus vulgaris. Xenobiotica 5: 563–571
Hao, O.J., Kim, H., Chang, P.C., (2000) Decolorization of wastewater. Crit. Rev. Environ. Sci. Technol. 30 (4), 449–505.
Haug W, Schmidt A, Nortemann B et al (1991) Mineralization of the sulfonated azo dye Mordant Yellow 3 by a 6aminonaphthalene-2-sulfonate-degrading bacterial consortium Applied Microbiology and Biotechnology 57:3144–3149.
Hu TL (1998) Degradation of azo dye RP2B by Pseudomonas luteola. Water Science and Technology 38: 299 – 306
576
�Kapdan IK, Özturk R (2005) Effect of parameters on color and COD removal performance of SBR: Sludge age and initial
dyestuff concentration. Journal of Hazardous Materials B 123: 217–222
Kapdan IK, Tekol M, Sengul F (2003) Decolorization of simulated textile wastewater in an anaerobic–aerobic sequential
treatment system. Process Biochemistry 38 (7) : 1031–1037
Keck A, Rau J, Reemtsma T et al (2002) Identification of quinoide redox mediators that are formed during thedegradation of
naphthalene-2-sulfonate by Sphingomonas xenophaga BN6. Applied Microbiology and Biotechnology 68: 4341–4349
Kudlich M, Bishop P, Knackmuss H-J et al (1996) Synchronous anaerobic and aerobic degradation of the sulfonated azo dye
Mordant Yellow 3 by immobilized cells from a naphthalenesulfonate-degrading mixed culture. Applied Microbiology and
Biotechnology 46: 597–603
Kudlich M, Keck A, Klein J (1997) Localization of the enzyme system involves in anaerobic reduction of azo dyes by
Sphingomonas sp. strain BN6 and effect of artificial redox mediators on the rate of azo dye reduction. Applied Microbiology
and Biotechnology 63: 3691–3694
Libra JA, Borchert M, Vigelahn L (2004) Two stage biological treatment of a diazo reactive textile dye and the fate of the
dye metabolites. Chemosphere 56 (2): 167–180
Lourenço ND, Novais JM, Pinheiro HM (2001) Effect of some operational parameters on textile dye biodegradation in a
sequential batch reactor. Journal of Biotechnology 89 (2–3): 163–174
Luangdilok W, Paswad T, (2000) Effect of chemical structures of reactive dyes on color removal by an anaerobic–aerobic
process. Water Science and Technology 42 (3–4): 377–382
Nigam P, Banat IM, Singh D (1996) Microbial process for the decolorization of textile effluent containing azo diazo and
reactive dyes. Process Biochemistry 31: 435–442
O’Neill C, Lopez A, Esteves S et al, (2000) Azo-dye degradation in an anaerobic– aerobic treatment system operating on
simulated textile effluent. Applied Microbiology and Biotechnology53 (2): 249–254
Pandey A, Poonam S, Leela I, (2007) Bacterial Decolorization and degradation of azo dyes, International Biodeterioration
and Biodegradation 59: 73–84
Panswad T, Luangdilok W, (2000) Decolorization of reactive dyes with different molecular structures under different
environmental conditions. Water Research 34 (17): 4177–4184
Pearce CI, Christie R, Boothman C et al, (2006) Reactive azo dye reduction by Shewanella Strain J18 143. Biotechnology
and Bioengineering 95: 692–703
Rau J, Knackmuss HJ, Stolz A (2002a) Effects of different quinoid redox mediators on the anaerobic reduction of azo dyes
by bacteria. Environmental Science and Technology 36: 1497–1504
Rau J, Maris B, Kinget Ret al, (2002b) Enhanced anaerobic degradation of polymeric azo compounds by Escherichia coli in
the presence of low-molecular-weight redox mediators. Journal of Pharmacy and Pharmacology 54: 1471–1479
Russ R, Rau J, Stolz A, (2000) The function of cytoplasmic flavin reductases in the reduction of azo dyes by bacteria.
Applied and Environmental Microbiology 66: 1429–1434
Semde R, Pierre D, Geuskens G, (1998) Study of some important factors involved in azo derivative reduction by Clostridium
perfringens. International Journal of Pharmacy 161: 45–54
Seshadri S, Bishop PL, Agha AM, (1994) Anaerobic/ aerobic treatment of selected azo dyes in wastewater. Waste
Management 14 (2): 127–137
Shaw CB, Carliell CM, Wheatley AD, (2002) Anaerobic/aerobic treatment of coloured textile effluents using sequencing
batch reactors. Water Research 36 (8): 1993–2001
Stolz A, (2001) Basic and applied aspects in the microbial degradation of azo dyes. Applied Microbiology and Biotechnology
56: 69–80
Tan NCG, Prenafeta-Boldu FX, Opsteeg JL et al, (1999) Biodegradation of azo dyes in cocultures of anaerobic granular
sludge with aerobic aromatic amine degrading enrichment cultures. Applied Microbiology and Biotechnology 51: 865–871
577
�Van der Zee FP, Bisschops IAE, Lettings G et al, (2003) Activated carbon as an electron acceptor and redox mediator during
the anaerobic biotransformation of azo dyes. Environmental Science and Technology 37: 402–408
Walker R, (1970) The metabolism of azo compounds: a review of the literature. Food Cosmetics Toxicol 8 (6): 659–676
Wang X, Cheng X, Sun D et al, (2008) Biodecolorization and partial mineralization of Reactive Black 5 by a strain
Rhodopseudomonas palustris. Journal of Environmental Sciences 20: 1218–1225
Wuhrmann K, Mechsner K, Kappeler T, (1980) Investigation on rate-determining factors in the microbial reduction of azo
dyes. Applied Microbiology and Biotechnology 9: 325–338
Xu M, Guo J, Sun G, (2007) Biodegradation of textile azo dye by Shewanella decolorationis S12 under microaerophilic
conditions. Applied Microbiology and Biotechnology 76: 719–726
ZaoyanY, Ke S, Guangliang S et al, (1992) Anaerobic–aerobic treatment of a dye wastewater by combination of RBC with
activated sludge. Water Science and Technology 26: 2093–2096
Zimmermann T, Kulla H, Leisinger T, (1982) Properties of purified orange II-azoreductase, the enzyme initiating azo dye
degradation by Pseudomonas KF46. European Journal of Biochemistry 129: 197–203
578
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Parameters Affecting Anaerobic Color Removal of Textile Wastewaters: An Overview
Author
Author
Cırık, Kevser
Çınar, Özer
Abstract
A summary of the resource.
Release of colored wastewaters represents a major environmental problem worldwide due to the toxicity, mutagenicity and carcinogenicity of the dyes and their breakdown products. Therefore much attention has been focused on the effective treatment of dyes discharged from the dying and textile industries. The most widely used dyes in industries are azo dyes which require anaerobic and aerobic phases for their complete biodegradation. Color is removed under anaerobic conditions in which azo dyes act an electron acceptor. Further, aerobic conditions are essential for removal of breakdown products which are known resist to biodegradation under anaerobic conditions. Thus using both anaerobic and aerobic stages represents both decolorization and mineralization of azo dyes. Anaerobic stage is the first and the most important phase for color removal, however; decolorization can be affected by so many parameters such as; organic carbon source added, microorganisms selected, dye structure, cycle time, sludge age, and alternative electron acceptors involved. This review article summarizes the results of several research studies dealing with the factors affecting anaerobic color removal efficiency.
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2010-06
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PeerReviewed
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https://omeka.ibu.edu.ba/files/original/47991fbd496bf3a175865f6572ad0472.pdf
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2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
Performance and Satisfaction of Work as Characteristics of Human Capital
(Comparative Analysis of Some Indicators of Human Capital in Several
Balkan Countries)
Alexi DANCHEV
Department of Economics and Administrative Sciences
Fatih University, Turkey
adanchev@fatih.edu.tr
Erkan ĠLGÜN
Department of Management
International Burch University, Bosnia and Herzegovina
eilguen@ibu.edu.ba
Abstract: The paper analyses the role of such elements of human capital as
performance and satisfaction of work for its further improvement. It is indicated that
due to its complex nature human capital is a core element in many sides of
development. Basic results of a survey of human capital carried out in Turkey,
Bosnia and Bulgaria are discussed. The multifarious effects of human capital are
analyzed indicating in particular the specific functions of performance and
satisfaction of work in its growth. From this perspective the authors look for a
broader vision of the role of satisfaction of work and its link with the performance to
improve the skill and knowledge regarded as basic indicators of human capital. The
conclusion is that despite regional differences the performance and satisfaction of
work are highly correlated with the income and the social setting within the team the
respondents work.
Introduction
The interest in the influence of human factors on economic growth and development is increasing,
which is result of many reasons. The main rationale maybe the understanding that while in the post-war
restoration of the world economy capital is of a crucial importance, nowadays human factors are decisive for the
success and survival in the sharply increasing competition in the global economy due to advantages given by the
new technologies. More and more the elements influencing human behavior in the reproduction process become
predominant in the theoretical and empirical studies on growth and development.
The present paper follows this tradition. It is aimed at tracing out the influence of such basic elements of
human capital as performance and satisfaction of job. We give short theoretical survey on the basic visions of the
role of performance and satisfaction of job in the human capital literature. Next we proceed with the empirical
study of the level of performance and satisfaction of job in three Balkan countries: Turkey, Bosnia and Bulgaria.
Finally we conclude.
The Theoretical Background
Human capital is the basic category, which reflects the contribution of labor to growth and
development. In the past it was interpreted as the level of education and experience (learning by doing, Arrow,
1962 and Sheshinski, 1967), which was complemented to the labor force indicators as for example the Harrodneutral technological progress, (Barro, and Sala-i-Martin, 2003).
While in the classic model of growth labor was included into the production function (the basic growth
model) as
Y = A(t)KαL1-α
the attempts to find more correct reflection of the labor contribution to growth resulted in the introduction of new
indicator – human capital as an exponential improvement of the quality of labor force mainly by means of
learning by doing mechanism.
Y = A(t)KαL[Leht)]1-α
ht
where e is the exponential improvement of the quality of labor force.
Nowadays it is clear that this very essential approach to such complicated factor of production as labor
is too far from outlining a realistic picture of the actual contribution of labor to growth. There are many reasons
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
to recommend the need for further improvements. First, human capital creation depends strongly on the health
status of the individuals, which is reflected by the health human capital indicator already commonly accepted in
the Development literature. The health is however not the only indicator necessary for more correct reflection of
labor force contribution to growth. People must be first of all satisfied with the current job they are employed
and next to be motivated to work further. Besides, we think that the job performance is standing on higher level
of contributive elements than satisfaction in sense than people may be motivated to work for many reasons one
of which can be the satisfaction to work.
Thus, we can complement the growth model with a new one, which describes the job performance as
JP = f(S, X1, X2, X3….Xn)
Where JP is the job performance
S – Satisfaction of work
X1, X2, X3 …Xn – factors influencing the performance.
The very satisfaction is however also function of other factors, some of which are common with the
performance model. So S = f(Z1, Z2, Z3…..Zn). We think of performance and satisfaction as subsets of human
capital set in which JP U S → HC.
Among the elements included into this set we can define:
1. Money paid for the job
2. Social surrounding
3. Social importance of the job
4. Nice spending of time
5. Team-working satisfaction feeling.
The choice of the variables was result of a scrutinize literature survey covering economic, social,
psychological and other studies on job performance and satisfaction. In most general terms job performance is
commonly identified with productivity. Kostiuk P. and Follmann D. (1989) are studying the effect of the on-thejob learning, experience and the individual characteristics on productivity regarding it as an indication of job
performance. Bishop (1990) however underlines that ―while job matching is an important phenomenon at most
small- and medium-sized establishments, it does not account for a significant share of the rise in average
productivity that occurs in the first year of tenure on the job‖.
The deeper roots of the job performance and satisfaction are coming from the value system of the
individuals, which origin was studying by Halaby (2003) paper of the link between the performance and the
entrepreneurial ability of ―the willingness to accept responsibility and the capacity to process information for the
purpose of effective problem-solving and decision-making under varying conditions‖. Halaby provides detailed
study of the entrepreneurial ability as a function of cognitive ability and talent, as well as ―decision-making and
problem-solving skills acquired through experience or schooling‖.
Wise (1975) early studies provide econometric estimations of job performance measured as the rate of
salary increase assumed to be adjusted ―to match individual performance‖. He found out that ―job performance,
as measured by rate of salary increase, was not only correlated with academic achievement but the evidence
suggested that mastery of academic subject matter contributed to an individual's ability to perform job-related
tasks‖.
Concerning the satisfaction of job a big variety of studies provide various evidences of its influence on
the formation of human capital. The attempts to develop a theory of job satisfaction dates back to 1970‘s with
incorporating differences in work values and perceived job characteristics as ―key explanatory variables‖
(Kalleberg, 1977). The theoretical backgrounds are empirically testing the relationship between job satisfaction
and such indicators as work values, job rewards associated with ―six dimensions of work-intrinsic, convenience,
financial, relations with co-workers, career opportunities and resource adequacy‖.
By highlighting the job satisfaction over the whole life-cycle of individuals Kalleberg and Loscocco
(1983) underline the importance of nonwork roles for explaining work-role outcomes. Two explanations are
formulated concerning the link between the age and job satisfaction: one that ―the relationship between age and
satisfaction is the result of generational differences in education and value systems (i.e., a cohort explanation)‖
and second, that ―this relationship is simply a function of older workers having moved into better jobs across
their careers (i.e., a life cycle explanation)‖. Janson and Martin (1982) find out that neither explanation is
adequate, leaving the question of what accounts for higher levels of satisfaction of older workers unresolved‖.
Since that time there is not a sufficient support of these two explanations.
Most of the literature however unambiguously indicates the direct link between education (the basic
factor of human capital) and job satisfaction. Glenn and Weaver (1982) empirically estimate that ―the total effect
of education is positive for both sexes but is considerably stronger for women than for men‖.
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
Short Characteristics of Human Capital in the Balkan area
It is difficult to present a short characteristic of human capital in the Balkan area as it is a category with
multifarious dimensions. Normally the share of expenditure on education in GDP is regarded as the most general
indicator at least as a necessary precondition for generating of human capital. It is presented in table 1 for the last
two decades, which are a period of big transformations in the Balkans. Nevertheless, the dynamics of this
indicator shows that there is not a big gap between the Balkan countries and the rest of Euroarea and the middle
income countries.
Country
Years
1990
2000
2008
Albania
6
3
3
Croatia
7
4
5
Bulgaria
5
4
4
Greece
2
3
3
Romania
3
3
3
Serbia
..
2
4
Slovenia
..
6
6
Turkey
2
3
4
Euroarea
5
4
5
Middle income countries
4
4
4
Table 1: The share of total expenditure on education as a % of GDP.
Source: World Development Indicators on Line, (2010)
http://ddp-ext.worldbank.org/ext/DDPQQ/report.do?method=showReport
More synthetic measure of the state of human capital in the Balkan area is given by the UNDP‘s Human
Development index (HDI), which ―is a summary composite index that measures a country's average
achievements in three basic aspects of human development: health, knowledge, and a decent standard of living‖
(UNDP, 2010). The dynamics of this indicator for the last three decades (Table 2) unambiguously indicates
convergence of the Balkan area to the advanced Western European economies, which is a good precondition for
further improvement of the quality of human capital in the area. The detailed analysis of the basic components of
the HDI reveals various details indicating the difficulties in this process. Not only increased funding is needed in
the crucial sectors forming human capital, serious institutional adjustment is also required to overcome the
difficulties of the transformation process in the formally centrally-planned economies in the area.
HDI
rank
8
22
25
29
45
61
63
67
70
Country
code
FRA
DEU
GRC
SVN
HRV
BGR
ROM
SRB
ALB
76
79
BIH
TUR
Country name
France
Germany
Greece
Slovenia
Croatia
Bulgaria
Romania
Serbia
Albania
Bosnia
and
Herzegovina
Turkey
1980
0.876
0.869
0.844
..
..
..
..
..
..
1985
0.888
0.877
0.857
..
..
..
..
..
..
1990
0.909
0.896
0.872
0.853
0.817
..
0.786
..
..
1995
0.927
0.919
0.874
0.861
0.811
..
0.780
..
..
2000
0.941
..
0.895
0.892
0.837
0.803
0.788
0.797
0.784
2005
0.956
0.942
0.935
0.918
0.862
0.829
0.824
0.817
0.811
2006
0.958
0.945
0.938
0.924
0.867
0.835
0.832
0.821
0.814
2007
0.961
0.947
0.942
0.929
0.871
0.840
0.837
0.826
0.818
..
0.628
..
0.674
..
0.705
..
0.730
..
0.758
0.803
0.796
0.807
0.802
0.812
0.806
Table 2: HDI is the Balkan countries for the period 1980 – 2007.
Source: UNDP, Human Development Reports, 2010, http://hdr.undp.org/en/statistics/data/
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
The Study
The role of performance and job satisfaction as preconditions for improvement of human capital cannot
be revealed by means of the official statistics, they are to be obtained by interviewing. Due to a project funded
by the Research fund of Fatih University data have been collected about the quality of human capital in three
Balkan countries: Turkey, Bosnia and Bulgaria. Although the collection of data is still on-going some ideas
about the role of performance and satisfaction of job on the formation of human capital can be formulated to
trace out the influence of human capital on growth more correctly.
The sample includes 426 interviews from Turkish citizen, 275 interviews from Bosnian citizens and 182
interviews from Bulgarian citizens. The samples are not representative so the results should be cautiously
interpreted.
The performance and job satisfaction were measured mainly by 5-scale level. Special attention has been
paid on the estimation of the match between the level of skill and knowledge on one hand and the requirements
of the present job on the other. The respondents have been asked by 5-scale codes to declare do they think they
have the skill and knowledge sufficiently enough to complete their job properly.
Among the factors influencing the ability and willingness to work (the basic elements of labor supply)
the respondents have to scale out:
1. The rise of the level of skill and knowledge they possess.
2. The efficiency of management in the firm they work in.
3. The problems in their personal life and health.
4. The state of economy in their country
5. The state of the world economy
Findings
Below we report only the basic characteristics of the indicators measuring job performance and
satisfaction. Detailed study of the links between these two indicators and the factors influencing their behavior
will be published after the completion of the collection of data.
The salary promotion as an indicator of job performance commonly used in the research studies reflects
only one side of the problem. Outside the attention remains another very important aspect of the job
performance: how the very respondents estimate their own performance. Certainly this is a subjective measure of
the performance, nevertheless it is important to know the own vision of their status and to juxtapose it with the
carrier promotion. Such a comparison may provide very interesting information for many sides beyond the job
performance. For example the gap between the carrier promotion (income growth) and the self estimation can be
regarded as a proxy of the level of corruption in society. On the other hand however it is well known fact that
normally everybody pretends to receive more than he actually deserves - an old tradition in the Balkan (and not
only in the Balkans of course). Our study provides information was based on the self-estimation principle: the
respondents had to declare their own estimation of their job performance during the current year and the last
three years. The results of the interviewing are indicated in table 3.
Level
of
performance
1. Lowest
2.
3.
4.
5. Highest
No.
of
answers
Turkey
Current year
0.7%
2.4%
18.2%
51.7%
27.0%
422
Bosnia
Last 3 years
0.7%
3.1%
17.9%
51.0%
27.3%
418
Current year
0.4%
0.8%
17.9%
58.9%
22.1%
263
Bulgaria
Last 3 years
1.1%
1.1%
19.5%
58.0%
20.2%
262
Current year
0.0%
1.7%
9.1%
44.6%
44.6%
175
Last 3 years
0.0%
1.1%
11.3%
40.7%
46.9%
177
Table 3: Self-estimation of job performance
As a whole the picture is of a relatively stable short-run dynamics (the last three years) of the job
performance in the countries of observation. This is an evidence of the stability of this indicator, which
accumulates the influence of many factors.
The level of satisfaction of job is measured in the similar way – by means of 5-scale discrete choice
presented in table 4. It is distributed as follows:
Level of satisfaction
Turkey
Bosnia
Bulgaria
1. Lowest
1.4%
1.1%
3.9%
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
2.
3.
4.
5. Highest
8.3%
33.7%
43.9%
12.7%
2.3%
19.9%
53.8%
22.9%
7.9%
37.1%
42.1%
9.0%
Table 4. The level of satisfaction of job
The influence of the factors on the level of job satisfaction has been measured in two aspects: factors
influencing high level of satisfaction and factors influencing low level of satisfaction. Several factors influencing
positively the level of satisfaction of job have been formulated, namely:
1. Giving good money to enjoy the life
2. Ability to meet very good friends
3. The understanding of the social importance of the job
4. Spending time very nicely during the working hours
5. The pleasure to work with the team.
The respondents rank the presented above alternatives in the following way: Bulgarian respondents
(136) give highest rank on the giving money to enjoy the life (29.4%) as the reason for the high level of job
satisfaction, followed by the understanding of the social importance of job (alternative 3) – 25,0% and the
pleasure to work with the team 19.1%. The ability to meet very good friends and the spending time very nicely
during the working hours have equal ranking of 13.2% (weighted average 30). Turkish respondents (366) are
distributed in the following way: 47.9% are satisfied from their job because it gives them money to enjoy the
life, 18.7% are satisfied as they find their job socially important, 12.7% enjoy their job because it gives them
ability to meet very good friends, 11.8% have a pleasure to work with the team and 8.8% are satisfied as they
spend very nice their time during the working hours. The Bosnian respondents are more evenly distributed in the
voting for their job satisfaction: like the previous respondents they give highest share of the job as a source of
having money to enjoy the life (33,4%), followed by almost equal share of the understanding of the social
importance of their work (22.2%) and the pleasure to work with the team (21.4%). Almost equal share is given
to the understanding of social importance of their job (11.7%) and the spending time very nicely during the
working hours (11.3%).
The results look quite realistic and allowing to draw important conclusions: there is a big resemblance
of the factors influencing satisfaction of job among the compared countries. Quite normal sounds the
predominance of the materially-related motivations as having money to enjoy the life followed by the social
importance of the performed job in all countries. It is also indication of our ability to create a network of data
collection producing comparable results despite the restriction of the non-representative sample.
Similar is the picture also related to the opposite side of job satisfaction – the reasons leading to its low
level. Although in all countries the answers of this question are small, nevertheless they are important for better
understanding of the reasons for dissatisfaction of job. Bulgarian sample has only 43 answer of the ranking of
reasons leading to low job satisfaction. The biggest share of the answers (65.1) is due to the too low level of
payment, followed by the unpleasant atmosphere in the team respondent works with (18,6%), uselessness of the
job for society (9.3%) and the job as boring and irritating activity (7%). The Turkish respondents (120 answers)
are distributed in the following way: Too low level of payment is indicated as the reason for low level of
satisfaction of job by 57.5%, 15.0% indicate as such a reason the unpleasant atmosphere in the team the
respondent works with, 14.2% as the job is found as boring and irritating, 8.4% as finding the job useless for
society and 5% as the lack of interesting persons in the firm. Bosnian respondents (52 answers) find the basic
reason for dissatisfaction of job the low level of payment (67.3%), following by boring and irritating work
(11.5%), the unpleasant atmosphere in the team the respondent works with (9.6%), with equal share (5.8%) of
the uselessness of the job for society and the lack of interesting persons in the firm.
Important information related both the job performance and satisfaction was hidden into the present and
past vision of the respondents for the correspondence between their level of experience and knowledge on one
hand and the adequate completion of the tasks they were responsible for - on the other. As to the present
correspondence between the level of experience and knowledge and the present job half of the Turkish
respondents thing it is good, 28.8%, - very good, 18.4% - average, 1.2% - low and 0.9% - very low. This
distribution for the Bulgarian respondents (174) is: 55.7% - very high, 32.2% - high, 7.5% - average and 4.6% low (0 answer of very low). The Bosnian respondents (270) give the following ranking of the correspondence
between the level of experience and knowledge and the completion of the tasks of the present job: 38.9% - very
high level of correspondence. 48.5% - high level, 11.9% - average level and by 0.4% for the low and very low
levels.
The distributions of the same problem for the past are as follows: Turkish respondents (420): 22.6% very high , 54.0% - high , 21.4% - average, 1.4% - low and 0.5% - very low; Bulgarian respondents (174): 45.4%
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�2nd International Symposium on Sustainable Development, June 8-9 2010, Sarajevo
- very high, 35.1% - high, 15.5% - average, 3.4% - low and 0.6% - very low; Bosnian respondents (263): 31.9%
as very high, 52.9% as high, 13.3% as average, 1.1% as low and 0.8% as very low.
The presented above analysis is an evidence of big similarity in the mechanisms of creating human
capital in the compared Balkan countries related to such a basic characteristics of human capital and job
performance and satisfaction. This is a good indicator of the expectations for their further successful integration
and accession to the EU – an ongoing tendency and strategic aim of the economic policy in the whole Balkans.
Conclusions
The presented above results of the empirical study of performance and job satisfaction as elements of
human capital indicate that there are good preconditions for its further growth and improvement in the selected
Balkan countries. There is a definite need for increasing the expenditure of R&D and education to materialize
these preconditions in real contributions to the economic growth of the region.
The collected information which is still on-going allows constructing various models of revealing
various sides of human capital and the ability of its improvement of the aims of reaching sustainable
development in the area.
Acknowledgements:
The work on this paper has been possible due to the project ―Managing human capital for the aims of
sustainable development (case study of some Balkan countries)" supported by the Scientific Research Fund
of Fatih University under the project number P51010901_1. We express our thanks for the ability to use this
support.
References
Arrow, K. J. (1963). Human Choice and Individual Values, 2nd edition. New Haven, Conn; Yale University Press.
Barro R. J. & Sala-i-Martin X. (2003). Economic Growth, Second Edition, Cambridge, MA: MIT Press.
Bishop J. H. (1990). Job Performance, Turnover, and Wage Growth, Journal of Labor Economics, (pp. 363-386), 8(3).
Glenn N. D. & Weaver Ch. N. (1982). Further Evidence on Education and Job Satisfaction, Social Forces, (pp. 46-55), 61(1).
Halaby Ch. N. (2003). Where Job Values Come from: Family and Schooling Background, Cognitive Ability, and Gender,
American Sociological Review, (pp. 251-278), 68(2).
Janson Ph. & Martin J. K. (1982). Source Job Satisfaction and Age: A Test of Two Views, Social Forces, (p. 1089) 60(4).
Kalleberg A.L. & Loscocco K. A. (1983). Aging, Values, and Rewards: Explaining Age Differences in Job Satisfaction.
American Sociological Review, (p. 89), 48(1).
Kalleberg A.L., (1977). Work Values and Job Rewards: A Theory of Job Satisfaction. American Sociological
Review,(p.124), 42.
Kostiuk P. F. & Follmann D. A. (1989). Learning Curves, Personal Characteristics, and Job Performance, Journal of Labor
Economics (pp. 129-146), 7 (2), 129-146.
Sheshinski, E. (1967). Optimal Accumulation with Learning by Doing. In Karl Shell (Ed), Essays on the Theory of Optimal
Economic Growth, (pp.31-52). Cambridge, MA: MIT Press.
UNDP, Human Development Reports, 2010, http://hdr.undp.org/en/statistics/data/
Wise, D. A. (1975). Personal Attributes, Job Performance, and Probability of Promotion. Econometrica, (p. 913), 43(5/6)
World Development Indicators on Line. (2010).
http://ddp-ext.worldbank.org/ext/DDPQQ/report.do?method=showReport
230
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Title
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Performance and Satisfaction of Work as Characteristics of Human Capital (Comparative Analysis of Some Indicators of Human Capital in Several Balkan Countries)
Author
Author
DANCHEV, Alexi
ILGÜN, Erkan
Abstract
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The paper analyses the role of such elements of human capital as performance and satisfaction of work for its further improvement. It is indicated that due to its complex nature human capital is a core element in many sides of development. Basic results of a survey of human capital carried out in Turkey, Bosnia and Bulgaria are discussed. The multifarious effects of human capital are analyzed indicating in particular the specific functions of performance and satisfaction of work in its growth. From this perspective the authors look for a broader vision of the role of satisfaction of work and its link with the performance to improve the skill and knowledge regarded as basic indicators of human capital. The conclusion is that despite regional differences the performance and satisfaction of work are highly correlated with the income and the social setting within the team the respondents work.
Date
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2010-06
Keywords
Keywords.
Conference or Workshop Item
PeerReviewed
HB Economic Theory