Gulen Eremektar

Istanbul Technical University, İstanbul, Istanbul, Turkey

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Publications (20)25.19 Total impact

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    Gulen Eremektar, Huseyin Selcuk, Sureyya Meric
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    ABSTRACT: Textile industry is one of the most common and essential sectors in the world. On the other hand, high volume of water consumption and varying wastewater characteristics due to many products such as dyes, biocides, carriers, detergents, etc. used in the process are the factors that have caused a continuous effort to find appropriate technologies to treat textile industry wastewater. In the last decade, the use of advanced oxidation processes (AOPs) has gained importance to degrade, decolorise and detoxicify the textile wastewater. However, the main mechanisms for AOPs for removing toxicity, thus, any contribution by the reduction of decreased inert factions in the effluent of textile wastewater are still to be studied. This study aimed to investigate the relation between inert COD fractions (which are characteristics in part of the influent wastewater, and in part generated in the biological treatment as the common used treatment process for textile industry) and effluent toxicity in the presence/absence of pre-ozonation. 18.5 mg/l of ozone dose was applied during 30 min oxidation on two wastewater samples taken from balancing tank of a textile industry localized in Istanbul, Turkey. A direct assessment method was used to determine inert COD fractions of the raw and ozonated wastewater samples. The toxicity of raw and treated was tested using newborn (<24 h) samples of Daphnia magna for 24 h exposure time. The soluble inert COD (SI) decreased significantly while soluble residual microbial product (SP) increased slightly due to preozonation. The sum of soluble inert fractions were found in the order of 17–18% and 20% of total COD for raw and preozonated samples. Preozonation decreased the toxicity of raw wastewater. This phenomenon was evidenced also by testing the effluents of the inert COD determination reactors.
    Desalination 06/2007; DOI:10.1016/j.desal.2006.02.096 · 3.96 Impact Factor
  • Hüseyin Selçuk, Gulen Eremektar, Süreyya Meriç
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    ABSTRACT: The present work evaluates pre-ozonation for removal of acute toxicity, color and COD as well as reduction of inert soluble COD fractions in two wastewater samples (S1 and S2) taken from a textile finishing industry, located in Istanbul (Turkey). The wastewater samples were oxidized at original pH of 8.6-8.8 under 18.5-24 mg/L of applied ozone doses. Acute toxicity was monitored using Daphnia magna. The results showed that pre-ozonation improved the biodegradability and reduced the acute toxicity. Acute toxicity in raw wastewaters was reduced by 80-90% using 129-200 mg/L transferred ozone (TrO(3)) concentrations. At this point, 86-96% of color, 33-39% of soluble COD and 57-64% of total COD were removed from wastewaters. Both color and COD parameters were found related to the acute toxicity of the wastewater. Pre-ozonation decreased the inert soluble COD fraction (S(I)) of raw wastewater while soluble product formation (S(P)) increased slightly (5-10 mg/L). However, residual COD (the sum of S(I) and S(P)) remained below discharge limit.
    Journal of Hazardous Materials 10/2006; 137(1):254-60. DOI:10.1016/j.jhazmat.2006.01.055 · 4.33 Impact Factor
  • Hüseyin Selçuk, Gulen Eremektar, Süreyya Meriç
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    ABSTRACT: The present work evaluates pre-ozonation for removal of acute toxicity, color and COD as well as reduction of inert soluble COD fractions in two wastewater samples (S1 and S2) taken from a textile finishing industry, located in Istanbul (Turkey). The wastewater samples were oxidized at original pH of 8.6-8.8 under 18.5-24 mg/L of applied ozone doses. Acute toxicity was monitored using Daphnia magna. The results showed that pre-ozonation improved the biodegradability and reduced the acute toxicity. Acute toxicity in raw wastewaters was reduced by 80-90% using 129-200 mg/L transferred ozone (TrO(3)) concentrations. At this point, 86-96% of color, 33-39% of soluble COD and 57-64% of total COD were removed from wastewaters. Both color and COD parameters were found related to the acute toxicity of the wastewater. Pre-ozonation decreased the inert soluble COD fraction (S(I)) of raw wastewater while soluble product formation (S(P)) increased slightly (5-10 mg/L). However, residual COD (the sum of S(I) and S(P)) remained below discharge limit.
    Journal of Hazardous Materials 10/2006; 137(1):254-60. DOI:10.1016/j.jhazmat.2006.01.055 · 4.33 Impact Factor
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    ABSTRACT: In this study, treatability of wastewaters generated from a water-based paint and allied products industry has been investigated. As the industry already houses a treatment facility that consists of a coagulation-flocculation unit followed by an activated sludge process, the experimental study focuses on using the existing treatment plant in the most efficient way. In this context the COD removal efficiencies and operating costs of different coagulants i.e., sodium bentonite, alum, FeCl(3) and FeSO(4) have been evaluated. By assessing the refractory COD content of the subsequent activated sludge system outlet, the coagulant yielding the optimal output has been addressed. The outcomes reveal that the optimum result can be obtained by applying 50 mg L(-1) of FeCl(3) coagulant at the original pH of the effluent.
    Journal of Environmental Science and Health Part A 02/2006; 41(9):1843-52. DOI:10.1080/10934520600779018 · 1.14 Impact Factor
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    ABSTRACT: The effect of ozonation on the biodegradability and acute toxicity of two frequently used textile dye assisting chemicals, namely natural tannin (NT) having an initial chemical oxygen demand (COD0) of 1195 mg L-1; initial total organic carbon (TOC0) of 342 mg L-1; initial 5th-day biochemical oxygen demand (BOD5,0) of 86 mg L-1; initial ultraviolet absorbance at 280 nm wavelength (UV280,0) of 32.2 cm-1; initial ultraviolet absorbance at 254 nm wavelength (UV254,0) of 19.35 cm-1 and synthetic tannin (ST); with a COD0 of 465 mg L-1; TOC0 of 155 mg L-1; BOD5,0 of 6 mg L-1; UV280,0 of 11.78 cm-1; UV254,0 of 13.74 cm-1 was investigated. Synthetic wastewater bearing these tannin formulations was individually prepared and subjected to ozonation at varying doses (500 and 1000 mg h-1), and pHs (3.5 and 7.0) to elucidate the effect of ozone dose and pH on oxidation efficiency. Changes in the environmental sum parameters chemical oxygen demand (COD), total organic carbon (TOC), 5th-day biochemical oxygen demand (BOD5), ultraviolet absorbance at 280 nm wavelength (UV280) and ultraviolet absorbance at 254 nm wavelength (UV254), the latter two representing the aromaticity and double bonds of the studied textile tannins, respectively, were monitored during the course of ozonation. In the second part of the study, the biodegradability and acute toxicity of the raw and pre-ozonated textile tannins were evaluated in terms of the BOD5 parameter and an activated sludge inhibition test, respectively. Results indicated no significant changes in acute toxicity for NT, whereas the inhibitory effect of ST could be completely eliminated after 40 min ozonation at a rate of 1000 mg h-1 (i.e., at a specific ozone dose of 1.4 mg (O)3 (mg COD0)-1 and a pH of 3.5. In conclusion, pre-ozonation appeared to be potential pretreatment option to achieve complete detoxification and a fair biodegradability improvement of the otherwise refractory synthetic tannin.
    Journal of Environmental Science and Health Part A 02/2006; 41(9):1873-86. DOI:10.1080/10934520600779083 · 1.14 Impact Factor
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    ABSTRACT: The present study refers to the outcomes of a detailed survey on the current situation of Turkish Urban Wastewater Treatment Plants (UWWTPs). The survey covers the identification of the population served by UWWTPs, presentation of the current technologies (physical, biological and advanced) applied in the country's UWWTPs, prevailing effluent disposal criteria, detailed assessment of UWWTPs selected from the Western part of Turkey representing highly urbanised and industrialised districts, and elucidation of needs for upgrading the selected UWWTPs to comply with the current discharge standards and irrigation water quality criteria. Following an extensive data collection and evaluation step, Turkey's most recent situation in the number of UWWTPs, effluent produced in Turkish municipalities both quantity-and quality-wise, urban wastewater treatment types and disposal methods as well as reuse potential of treated urban wastewater have been presented and discussed.
    International Journal of Environment and Pollution 01/2006; 28(1-2). DOI:10.1504/IJEP.2006.010879 · 0.30 Impact Factor
  • Aatcc Review 01/2006; 6(5):43-48. · 0.25 Impact Factor
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    ABSTRACT: In the present study, the decomposition of two biocides used in the textile finishing process with Advanced Oxidation Processes (AOPs) has been studied. Different AOPs, i.e O3/OH-, TiO2/UV-A and Fe2+/H2O2 have been used representing mutually combined components of the chemically and photochemically driven advanced oxidation systems. The course of reaction was examined by changes in chemical oxygen demand (COD), total organic carbon (TOC) and acute toxicity towards the water flea Daphnia magna (assessed in terms of the effective dilution ratio LD50). Particular attention has been paid to determine the inhibitory effect of raw and ozonated biocides on biological activated sludge consortium at concentrations typically encountered in textile finishing effluents. Significant oxidation and mineralization of both biocides could be achieved employing ozonation at pH = 11.5 and heterogeneous photocatalysis (TiO2/UV-A) at pH = 5.0, whereas Fenton's reagent appeared to be less effective in COD and acute toxicity abatement.
    Water Science & Technology 02/2005; 52(10-11):309-16. · 1.21 Impact Factor
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    ABSTRACT: This study evaluates the feasibility of water minimization and wastewater reuse for a wool finishing textile mill. The evaluation process is based upon a detailed analysis on water use, process profile and wastewater characterization, indicating a potential for 34% reduction in water consumption and for 23% of wastewater recovery for reuse. Wastewater reuse requires treatment and results in a remaining wastewater stream with stronger character and consequently more costly to treat. The feasibility includes technical considerations for appropriate treatment alternatives and related cost factors for water consumption, treatment for reuse and for discharge either to sewer or to receiving media.
    Journal of Environmental Science and Health Part A 02/2004; 39(7):1819-32. DOI:10.1081/ESE-120037880 · 1.14 Impact Factor
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    Fresenius Environmental Bulletin 01/2004; 13(10):1040-1044. · 0.53 Impact Factor
  • Fresenius Environmental Bulletin 01/2004; 13(10):1057-1060. · 0.53 Impact Factor
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    ABSTRACT: Water minimization and exploration of the potential for wastewater recovery and reuse are priority issues of industrial wastewater management. They are extremely significant for the textile industry commonly characterized with a high water demand. The study presents a detailed in-plant control survey for a wool finishing plant. A comprehensive process profile and wastewater characterization indicate that process water consumption can be reduced by 34%, and 23% of the wastewater volume can be recovered for reuse. Treatability of reusable wastewater fraction and the effect of in-plant control applications on effluent treatability were also investigated.
    Water Science & Technology 02/2002; 45(12):287-95. · 1.21 Impact Factor
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    ABSTRACT: Corn wet mill effluents are studied in terms of their characteristics relevant for biological treatment. They have a high COD of mainly soluble and biodegradable nature, with practically no soluble inert components. They generate a relatively high level of soluble residual metabolic products, which affects the choice of the appropriate biological treatment and favors aerobic activated sludge process. Experimental assessment of process kinetics yields typical values. Hydrolysis of the slowly biodegradable COD, the rate limiting step for the utilization of substrate, is characterized by an overall rate coefficient, which is within the range commonly associated for the hydrolysis of starch.
    Water Science & Technology 02/2002; 45(12):339-46. · 1.21 Impact Factor
  • Fresenius Environmental Bulletin 01/2001; 10(6):539-544. · 0.53 Impact Factor
  • G. Eremektar, F. Germirli Babuna, O. Ince
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    ABSTRACT: In this study, the effluent of an alcohol distillery after passing through a chemical treatment is characterized in terms of its inert COD Suctions and the changes likely to be induced by two‐stage biological treatment on the magnitude of these fractions are observed. The experimentally obtained results indicated that the anaerobic treatment gives lower soluble inert COD fractions than a corresponding aerobic treatment for the investigated wastewater. Therefore, the preference of anaerobic treatment instead of an aerobic one as the first stage is ascertained. The anaerobic first stage has a COD removal efficiency of 96 %, whereas with a subsequent aerobic treatment 79 % removal can be achieved on the basis of the stoichiometry of the inert COD. The anaerobic full‐scale plant performance of 80 % can be improved up to 96 %.
    Journal of Environmental Science and Health Part A 06/1999; A34(6):1329-1340. DOI:10.1080/10934529909376899 · 1.14 Impact Factor
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    ABSTRACT: The study emphasizes wastewater characteristics of two different textile plants as they apply to biological treatment. Although conventional characterization reveals no major differences, the effluents from the acrylic fiber and yarn dyeing plant exhibit all the properties of a non-biodegradable wastewater. Appropriate pretreatment consisting of partial chemical oxidation with H2O2 reduces its COD content to 700 mg I−1, almost entirely biodegradable whereas COD fractionation indicates that the effluents of the cotton knit dyeing plant contain 9% residual fractions. Experimental investigation shows that most kinetic and stoichiometric properties of both wastewaters are compatible with that of domestic sewage with the exception of a much slower hydrolysis rate.
    Water Science & Technology 01/1999; 40(1):145–152. · 1.21 Impact Factor
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    ABSTRACT: Poultry processing generates strong wastewaters with characteristics that may be tailored by appropriate adjustment of the operation. The organic content has a residual fraction in the order of 200–400 mgl−1, depending on the strength of the wastewater. The values of kinetic and stoichiometric constants related to biological treatability are observed to be quite comparable with domestic sewage. The hydrolysis of slowly biodegradable organics is best described by dual-hydrolysis kinetics with appreciably different rate constants for soluble and particulate components. The experimental results of the study may be used to evaluate the achievable compliance with existing effluent limitations and to define the optimum in-plant operation and wastewater treatment and disposal strategy.
    Water Science & Technology 01/1999; 40(1):323-329. DOI:10.1016/S0273-1223(99)00401-1 · 1.21 Impact Factor
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    ABSTRACT: Modern laying chicken plants generate strong wastewaters of limited flow rate, with COD concentrations up around to 10 g I−1, with a soluble portion of 50% and high nitrogen and phosphorus contents. The unit wastewater flow is as low as 0.003–0.005 I chicken−1 day+ and the unit organic load is assessed as 0.03 g COD chicken−1 day−1. COD fractionation reveals that the soluble residual portion accounts for 350 mg I−1 in the chicks step and 980 mg I−1 in the laying step for aerobic treatment. When anaerobic treatment is applied this residual fraction is likely to exhibit an increase of around 60 to 80%. These observations underline the significance and the need of setting effluent limitations attainable by biological treatment, if evidence is presented that they do not pose appreciable environmental problems such as toxicity, colour, etc. This is especially true for laying chicken plant effluents, due to their intermittent mode of generation and their limited volume.
    Water Science & Technology 01/1999; 40(1):207–213. · 1.21 Impact Factor
  • Fresenius Environmental Bulletin 01/1998; 7:959-966. · 0.53 Impact Factor
  • O TUNAY, I KABDASLI, G EREMEKTAR, D ORHON
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    ABSTRACT: The requirement of color removal has promoted the research in this field. However, there is still a lack of understanding of colour problems. In this paper a literature review is made to assess the information on color removal and need for systematic evaluation of the results is emphasized. Experimental studies are conducted on the textile dyeing wastewaters applying chemical precipitation, chemical oxidation, adsorption and their combination. Results of the study are evaluated and discussed within the context of a systematic approach.
    Water Science & Technology 01/1996; 34(11):9-16. DOI:10.1016/S0273-1223(96)00815-3 · 1.21 Impact Factor