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Öğe Adaptive network fuzzy inference system modeling for the input selection and prediction of anaerobic digestion effluent quality(ELSEVIER SCIENCE INC, 2011) Erdirencelebi, Dilek; Yalpir, SukranThis paper presents the development and evaluation of three adaptive network fuzzy inference system (ANFIS) models for a laboratory scale anaerobic digestion system outputs with varied input selection approaches. The aim was the investigation of feasibility of the approach-based-control system for the prediction of effluent quality from a sequential upflow anaerobic sludge bed reactor (UASBR) system that produced a strong nonlinearship between its inputs and outputs. As ANFIS demonstrated its ability to construct any nonlinear function with multiple inputs and outputs in many applications, its estimating performance was investigated for a complex wastewater treatment process at increasing organic loading rates from 1.1 to 5.5 g COD/L d. Approximation of the ANFIS models was validated using correlation coefficient. MAPE and RMSE. ANFIS was successful to model unsteady data for pH and acceptable for COD within anaerobic digestion limits with multiple input structure. The prediction performance showed a high feasibility of the model-based-control system on the anaerobic digester system to produce an effluent amenable for a consecutive aerobic treatment unit. (C) 2011 Elsevier Inc. All rights reserved.Öğe Anaerobic Treatment of Strong Character Dairy Wastewaters in Sequential UASBRs: Adaptation Period COD Removal and pH/HCO(3)(-)/VFA Balance(SCIENCE PRESS BEIJING, 2009) Gokmen, Emine; Piskin, Funda; Erdirencelebi, DilekDairy wastewaters of strong acidic character from yoghurt and white cheese production units in small dairy plants were fed to sequential upflow anaerobic sludge blanket reactors. The reactors were monitored for organic matter removal, pH, HCO(3)(-) and volatile fatty acid (VFA) balance during the adaptation period. The wastewaters were rich in organic acids and fat as organic matter and deficient in nitrogen and sulfate. Rapid acidification lowered the pH consuming alkalinity provided in the feed solution. As one reactor configuration was not sufficient for efficient VFA and organic matter removal, second stage UASB reactors were configured into the system. Organic loading rates (OLRs) ranged from 1.12-1.33 g COD/L.d up to 5.3-6.5 g COD/L.d where the reactors' performance ameliorated with increasing OLRs after ammonia nitrogen and sulfate were added to the feed solution completing adaptation period in organic matter and VFA removal at the sequential mode in 71 days.Öğe Degree of sulfate-reducing activities on COD removal in various reactor configurations in anaerobic glucose and acetate-fed reactors(WILEY, 2007) Erdirencelebi, Dilek; Ozturk, Izzet; Cokgor, Emine Ubay; Tonuk, Gulseren UbaySulfate-reduction data from various anaerobic reactor configurations, e.g., upflow anaerobic sludge blanket reactor (UASBR), completely stirred tank reactor (CSTR), and batch reactor (BR) with synthetic wastewaters, having glucose and acetate as the substrates and different levels of sulfate, were evaluated to determine the level of sulfate-reducing activity by sulfate-reducing bacteria coupled to organic matter removal. Anaerobic reactors were observed for the degree of competition between sulfate-reducing sulfidogens and methane producing bacteria during the degradation of glucose and acetate. Low sulfate-reducing activity was obtained with a maximum of 20% of organic matter degradation with glucose-fed upflow anaerobic sludge bed reactors (UASBRs), while a minimum of 2% was observed with acetate-fed batch reactors. The highest sulfate removal performance (72-89%) was obtained from glucose fed-UASB reactors, with the best results observed with increasing COD/SO4 ratios. UASB reactors produced the highest level of sulfidogenic activity, with the highest sulfate removal and without a performance loss. Hence, this was shown to be the optimum reactor configuration. Dissolved sulfide produced as a result of sulfate reduction reached 325 mg/L and 390 mg/L in CST and UASB reactors, respectively, and these levels were tolerated. The sulfate removal rate was higher at lower COD/SO4 ratios, but the degree of sulfate removal improved with increasing COD/SO4 ratios.Öğe Diagnosis of the anaerobic reject water effects on WWTP operational characteristics as a precursor of bulking and foaming(IWA PUBLISHING, 2015) Erdirencelebi, Dilek; Kucukhemek, MuratThis study investigates the effects observed on operational parameters in a large and full-scale wastewater treatment plant subjected to anaerobic reject water (ARW) diversion off the main line for a 3-month period and further monitoring for a 2-year period. The plant's secondary unit consists of a two-stage plug-flow-modified Bardenpho process receiving wastewater from both municipal and industrial origins. As a result, ARW was found to have a direct effect on bulking in secondary clarifiers and foaming in anaerobic digesters (AD) despite its relatively small flow rate. During the cut-off period a highly stable sludge volume index at 80 mL g(-1) level was obtained in the secondary clarifiers, effluent suspended solids concentration was reduced and continuous feeding to AD was recovered. Sludge density increased in the thickeners during hot season. Secondary clarifiers showed good and stable settleability despite low dissolved oxygen, food/microorganism ratio and high sludge retention time and ammonium levels in the biological unit. The bulking and foaming effect was presented on the plant's internal flow balance. ARW needs serious consideration for elimination by appropriate technologies because of its high potential as a multi-dimensional pollutant source, not only as a carrier of nutrients but also as a possible carrier of filamentous bacteria, which might promote chronic seeding and retention in the system.Öğe Effect of COD/SO42- ratio on anaerobic treatment of landfill leachate during the start-up period(TAYLOR & FRANCIS LTD, 2012) Yilmaz, Tuba; Erdirencelebi, Dilek; Berktay, AliThis study investigates the performance of an anaerobic baffled reactor (ABR) during the start-up period of raw young landfill leachate treatment at two chemical oxygen demand (COD) to SO42- ratios of 20 and 4. The reactor was operated at ambient temperature and low organic loading rates (0.52, 0.76 and 1.05 kgCOD/m(3) per day). During the study, sulfate-reducing bacteria (SRB) activity increased at the lower ratio of COD/SO42- producing higher levels of sulfide and alkalinity. The dissolved sulfide concentration reached an inhibitory level above 250 mg/L, which caused a sharp reduction in the total COD removal efficiency from 77-80% to 32%. Total volatile fatty acid (TVFA) production proceeded at a constant level despite increased organic loading. As the effluent total and organic COD concentrations increased, the inhibitory effect of the inborn sulfide was correlated to the limitation experienced in the hydrolysis/acidogenesis stages, and thus VFA production and organic matter removal.Öğe Effects of 4-Chloro-Aliphatic Hydrocarbons on Microbial Activities of Anaerobic Landfill Leachate Digestion(SCIENCE PRESS BEIJING, 2009) Erdirencelebi, Dilek; Ozturk, IzzetThree four-chloro-aliphatic hydrocarbons (carbon tetrachloride (CT), tetrachloroethylene (PCE) and 1, 1, 2, 2-tetrachloroethane (1, 1, 2, 2-PCA)) were spiked individually at concentrations from 0.145 mg/L to 2.4 mg/L to anaerobic batch reactors treating young landfill leachate undergoing competition between main microbial groups of anaerobic consortia for an experimental period of four months. The effect of chlorinated compounds on the reactors' organic matter removal performance and microbial activities was examined. Dissolved organic matter was removed at similar rates in all reactors. Gas production ceased in CT receiving reactors and decreased in PCE receiving reactors revealing inhibition on methanogens with no effect in PCA receiving reactors. Sulfate-reducing bacteria's activity was less inhibited by chlorinated aliphatic compounds than methanogenic activity. Chlorinated aliphatic hydrocarbons (CAHs) were monitored and biotransformation of PCE and PCA to TCE and 1, 1, 2-TCA was observed via reductive dechlorination and dehydrohalogenation.Öğe Operational strategies and environmental conditions inducing aerobic denitritation in short-cut biological nitrogen removal at side-line treatment(TAYLOR & FRANCIS INC, 2017) Erdirencelebi, Dilek; Koyuncu, SerdarFactors promoting aerobic denitritation in a pilot-scale short-cut biological nitrogen removal (SBNR) process were investigated. The study implemented optimization of nitrogen removal in the anaerobic reject water (ARW) having a low organic C:N ratio ARW was produced in a large-scale municipal wastewater treatment plant (WWTP). Aerobic denitritation occurred consistently during study of a specific period of sequential batch reactor (SBR) where nitrite removal under fully aerobic conditions was obtained with a switch from oxygen to nitrite respiration, creating an aerobic (high oxidation-reduction potential) condition. Specific factors inducing aerobic denitritation were found related to several parameters as ammonium concentration, temperature, feeding mode, duration of the oxic stage and substrate availability due to beta-oxidation of lipid matter. Microbial analyses indicated a higher increase in nitrite reducing than ammonium oxidizing activity, as an evidence for nitrifying denitrifier bacterial dominance in the biomass. The reaction induced a reduction in the inhibitory products of the process as volatile fatty acids (VFAs) and free nitrous oxide (FNA), produced bicarbonate and increased removal efficiency of ammonium and nitrite, thus, total nitrogen. The outcome presents potential ways for further saving on aeration and chemical need via operational means, while taking advantage of the slowly degrading organic matter on SBNR performance.Öğe Optimization of Biological Nitrogen Removal over Nitrite in the Presence of Lipid Matter by Regulation of Operational Modes(ASCE-AMER SOC CIVIL ENGINEERS, 2018) Erdirencelebi, Dilek; Koyuncu, SerdarOptimization of total nitrogen (TN) removal via the nitrite path was studied at a sequential batch reactor (SBR) from anaerobic reject water (ARW) with a content of slowly degrading organic matter of lipid structure. The study was conducted as a pilot-scale side-line treatment in a large-scale municipal and industrial wastewater treatment plant (WWTP). Operational mode was modified based on feeding pattern, sequence order, phase duration, and number to maximize TN removal and minimize lipid-related interferences. Ammonium loading rate (ALR) proceeded at 0.2-0.7kgN/m3day and the optimum range was determined for maximum TN removal. An insufficient HCO3-/N ratio was further lowered by volatile fatty acids (VFA) production via beta-oxidation of long-chain fatty acids (LCFA) during nitritation. The organic content of ARW and VFA showed a low degradability by denitrifying bacteria and limited TN removal. Modifications in the operational mode increased ammonium and nitrite removal and reduced toxic-free VFA and nitrous acid (FNA) with increased anoxic and aerobic denitritation. Ammonium nitrogen at 180-478mgN/L was reduced to approximately 20mgN/L in all effluents and TN removal was achieved at 84-86%. Temperature sensitivity was higher for denitritation than nitritation. (C) 2017 American Society of Civil Engineers.Öğe Organic Matter Removal Kinetics and Sulfide Inhibition Pattern of Young Landfill Leachate Treatment(SCIENCE PRESS BEIJING, 2009) Erdirencelebi, Dilek; Ozturk, IzzetYoung landfill leachate digestion was monitored for soluble organic matter removal and sulfide production in anaerobic batch reactors. COD removal kinetics and inborn sulfide inhibition pattern were determined according to extended Monod kinetics for product inhibition. The inhibition pattern suited noncompetitive inhibition model with a critical inhibitor concentration (K(i)) of 850 mg S(2-)/L. Kinetic constants k and K(s) were determined accordingly. Organic matter removal followed a second order reaction kinetics. The maximum dissolved sulfide production obtained was 450 mg S(2-)/L and COD removal proceeded at a range of 81-93% with a minimum level of 67-76% as a result of a drop in pH intensifying H(2)S toxicity. Organic loading rate was applied at values from 0.18 kg COD/m(3).d to 0.5 kg COD/m(3).d where increasing rates enhanced methanogenic activity and sulfide production was stabilized at a level of 100-130 mg S(2-)/L accordingly. Results showed that methanogenic activity ameliorated at higher OLRs indicating that they were also subject to competition for substrate as well as sulfide inhibition despite a high COD/SO(4) ratio.Öğe Removal of Cr (VI) in Anoxic and Sulfate-Reducing SBRs(SCIENCE PRESS BEIJING, 2011) Erdirencelebi, Dilek; Yilmazturk, Derya; Yel, EsraMicrobial uptake of Cr(VI) at 3.2-10.4 mg/L dosing pattern in weekly sequential periods was investigated under anoxic and sulfate-reducing conditions in sequential batch reactors (SBR). Cr (VI)'s fate and acute effect was also determined on nitrate and organic matter (COD) reduction of unacclimated sludge cultures with methanol as substrate. Chromium (VI) was removed at an efficient level throughout the study with adaptation signs. Chromium's inhibitory effect was not observed on nitrate reduction which reached high levels following a three week adaptation period where organic matter reduction correlated to other mechanisms than nitrate reduction was altered. A higher yield of 0.88 and a chromium removal in relation to biomass was obtained in anoxic conditions. Organic matter usage was inhibited in both SBR where sulfate reduction was altered at the maximum dosing and accumulated in the reactor.Öğe System performance in UASB reactors receiving increasing levels of sulfate(WILEY, 2007) Erdirencelebi, Dilek; Ozturk, Izzet; Cokgor, Emine UbayGlucose-fed high-rate UASB reactors were tested at three COD/SO4 ratios and hydraulic retention times to promote sulfate reducing activity and observe the effects on reactor performance. Different COD/SO4 ratios (20, 10, and 5) resulted in changes in organic matter removal, methane production, alkalinity, dissolved sulfide and biomass concentrations and profile. The COD removal dropped from 95 to 80-84% at the lowest COD/SO4 ratio. Sulfate was removed at 79 to 89% at the highest ratio and dropped to 72 to 74% with increasing sulfate loading. Alkalinity was produced at higher levels with increasing sulfate loading. Specific methane production dropped with decreasing hydraulic retention times. Sulfate-reducing activity used a maximum of 11.7% of organic matter at the highest sulfate loading level, producing a slight shift to sulfate-reducing activity in the substrate competition between sulfate-reducing bacteria and methanogens. Increased sulfate loading at COD/SO4 ratios of 10 and 5 caused deterioration of the concentration profile of the sludge, resulting in biomass washout and decreased volatile fraction of biosolids in the reactors.Öğe Treatment of high-fat-containing dairy wastewater in a sequential UASBR system: influence of recycle(WILEY-BLACKWELL, 2011) Erdirencelebi, DilekBACKGROUND: Raw cheese whey originating from white cheese production results in a strong and complex wastewater excessively rich in organic matter (chemical oxygen demand, COD=28-65 g L(-1)), fatty matter (14-24.5 g L(-1)) and acidity (3.9-6.1 g L(-1)). It was treated in a three-stage configuration consisting of a pre-acidification (PA) tank and sequential upflow anaerobic sludge bed reactors (UASBRs) at 2.8-7 g COD L(-1) day(-1) organic loading rates, during which the effects of effluent recycling at low rates and promoted SRB activity were investigated. Acidification, volatile fatty acids (VFA), COD and fatty matter removal and volatile solids were monitored throughout the system during the study. RESULTS: Recycling of the effluent promoted VFA and COD removal as well as pH stability in both stages of the UASBRs and the effluent where high alkalinity levels were recovered reducing alkali requirement to 0.05 g OH g(-1) COD(applied). Higher removal rates of 71-100 and 50-92% for VFA and COD were obtained by use of recycling. Fatty matter was removed at 63-89% throughout the study. Volatile solids build-up was significant in the inlet zones of the UASBRs. CONCLUSIONS: The system produced efficient acidification in the PA tank, balanced pH levels and an effluent high in alkalinity and BOD/COD ratio. Efficient VFA removal and solids immobilization was obtained in both stages up to the highest loading rate. Recycling improved the system performance under high fatty matter loading conditions. A major advantage of the sequential system was that the second stage UASBR compensated for reduced performance in the first stage. (C) 2010 Society of Chemical Industry
