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Öğe Anaerobic/aerobic treatment of a simulated textile wastewater(Elsevıer Science Bv, 2008) Işık, Mustafa; Sponza, Delia TeresaA sequential anaerobic/aerobic reactor system was used to treat a simulated textile wastewater containing azo dyes (mixing of 50 mg L-1 of Reactive Black 5, 50 mg L-1 of Direct Red 28, 50 mg L-1 of Direct Black 38, 50 mg L-1 Direct Brown 2 and 50 mg L-1 of Direct Yellow 12 as 250 mg L-1 of total concentration), soluble starch, carboxymethyl cellulose (CMC), acetic acid, glucose, salts, acids and other additives. Hydraulic retention times (HRTs) were changed to determine the effect of HRT on removal efficiencies of color, COD and total aromatic amine (TAA) through 186 days containing 46 days of steady-state and acclimation periods. COD and color removal efficiencies varying between 97% and 91 % and between 84% and 91 % were obtained at a total HRT of 19.17 and 1.22 days in combined anaerobic/aerobic system, respectively. The azo dyes decolorized under reductive anaerobic conditions in very short HRTs but the breakdown products were not ultimately metabolized and accumulated under anaerobic conditions. In the sequential aerobic stage the significant part of TAA was removed successfully while the color removal slightly increased with TAA removal efficiencies of 70-85% at total HRTs of 8.85 and 6.05 days, respectively. Increases in HRT provide enough time for partial mineralization of COD and intermetabolites in anaerobic and/or anaerobic/aerobic systems. (c) 2007 Elsevier B.V. All rights reserved.Öğe Biological treatment of acid dyeing wastewater using a sequential anaerobic/aerobic reactor system(2006) Işık, Mustafa; Sponza, Delia TeresaThe treatment of the wastewater taken from a wool dyeing processing in a wool manufacturing plant was investigated using an anaerobic/aerobic sequential system. The process units consisted of an anaerobic UASB reactor and an aerobic CSTR reactor. Glucose, alkalinity and azo dyes were added to the raw acid dyeing wastewater in order to simulate the dye industry wastewater since the raw wastewater contained low levels of carbon, NaHCO3 and color through anaerobic/aerobic sequential treatment. The UASB reactor gave COD and color removals of 51-84% and 81-96%, respectively, at a HRT of 17 h. The COD and color removal efficiencies of the UASB/CSTR sequential reactor system were 97-83% and 87-80%, respectively, at a hydraulic retention time (HRTs) of 3.3 days. The aromatic amines (TAA) formed in the anaerobic stage were effectively removed in the aerobic stage. © 2006 Elsevier Inc. All rights reserved.Öğe Fate and toxicity of azo dye metabolites under batch long-term anaerobic incubations(Elsevier, 2007) Işık, Mustafa; Sponza, Delia TeresaAnaerobic biodegradability and toxicity of five azo dye metabolites (Reactive Black 5, RB 5; Direct Red 28, DR 28; Direct Black 38, DB38; Direct Brown 2, DB2; Direct Yellow 12, DY-12) at parent azo dyes concentrations varying between 200 and 1800 mg l?1 of were studied under long-term incubations such as 72 days. The metabolites of DB 38 and DB2 azo dyes at a concentration of 1800 mg l?1, had low toxicity effect on methanogenic bacteria. TAA measurements in the beginning and last period of incubation period showed that the recovery percentages of aromatic amines for DR 28, DB 38, DB 2 and DY 12 azo dyes, were 57.6, 69.4, 66.5, and 77.1%, respectively. The low recovery of aromatic amines (57–77%) from the reduction of azo dyes was probably due to low level of cleveage of aromatic ring resulting in minor anaerobic transformation of azo dye structure. This study showed that azo dye metabolites (aromatic amines) are partly persistent under anaerobic conditions and had low toxicity under long-term incubations.Öğe Hydrocarbon degradation abilities of psychrotolerant Bacillus strains(American Institute of Mathematical Sciences, 2017) Kolsal, Fulya; Akbal, Zeynep; Liaqat, Fakhra; Gök, Oğuzhan; Sponza, Delia Teresa; Eltem, RenginBiodegradation requires identification of hydrocarbon degrading microbes and the investigation of psychrotolerant hydrocarbon degrading microbes is essential for successful biodegradation in cold seawater. In the present study, a total of 597 Bacillus isolates were screened to select psychrotolerant strains and 134 isolates were established as psychrotolerant on the basis of their ability to grow at 7 degrees C. Hydrocarbon degradation capacities of these 134 psychrotolerant isolate were initially investigated on agar medium containing different hydrocarbons (naphthalene, n-hexadecane, mineral oil) and 47 positive isolates were grown in broth medium containing hydrocarbons at 20 degrees C under static culture. Bacterial growth was estimated in terms of viable cell count (cfu ml(-1)). Isolates showing the best growth in static culture were further grown in presence of crude oil under shaking culture and viable cell count was observed between 8.3 x 10(5)-7.4 x 10(8) cfu ml-1. In the final step, polycyclic aromatic hydrocarbon (PAH) (chrysene and naphthalene) degradation yield of two most potent isolates was determined by GC-MS along with the measurement of pH, biomass and emulsification activities. Results showed that isolates Ege B.6.2i and Ege B.1.4Ka have shown 60% and 36% chrysene degradation yield, respectively, while 33% and 55% naphthalene degradation yield, respectively, with emulsification activities ranges between 33-50%. These isolates can be used to remove hydrocarbon contamination from different environments, particularly in cold regions.Öğe Removals of non-analogous OTC and BaP in AMCBR with and without primary substrate(TAYLOR & FRANCIS, 2016) Çelebi, Hakan; Gök, Oğuzhan; Sponza, Delia TeresaAnaerobic biodegradation of mixed non-analogous two substrates was studied in a binary system with and without the primary substrate using an anaerobic multichamber bed (AMCBR). In the binary mixture, the biodegradation of less-degradable oxytetracycline (OTC) was restarted in the presence of more degradable benzo[a]pyrene (BaP) in the initial runs of the AMCBR, but enhanced biodegradation of the more recalcitrant OTC occurs in the later runs of the AMCBR due to enhanced biomass growth on dual substrates without the primary carbon source. The biodegradation yields of the OTC, BaP were discussed with sole-substrate systems and with the dual substrate system in the presence of the primary substrate. The maximum OTC and BaP yields were 93% in Run 3 with the primary substrate, while the maximum BaP and OTC yields were 95%, 98% in Run 3 without the primary substrate. A dual form of the Monod was found to adequately predict the substrate interactions in the binary mixture of OTC and BaP using only the parameters derived from batch experiments. At low BaP (4 mg L-1) and OTC (40 mg L-1) concentrations, a non-competitive inhibition does not affect the binding of the substrate and so the K-s were was not affected while the mu(max) was lowered. At high BaP (10 mg L-1) and OTC (100 mg L-1) concentrations, the BaP and OTC were biodegraded according to competitive inhibition with increased K-s while mu(max) was not affected. BaP and OTC were biodegraded according to Haldane at high concentrations (>10 mg L-1 for BaP, 100 mg L-1 OTC) where they were used as the sole substrate.
