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Turan M.,Technical University of Istanbul | Ozdemir O.,Kayseri Metropolitan Municipality
Fresenius Environmental Bulletin | Year: 2011

A pilot-scale submerged membrane bioreactor (SMBR) with flat sheet ultrafiltration module was used to treat a municipal wastewater. Permeate extraction was carried out intermittently under a suction pressure in the range of 0.1-0.5 bar. The module was aerated from below the ultrafiltration module to provide cross-flow effect and oxygen requirement for the biological process. Active sludge from municipal wastewater treatment plant (WWTP) of Kayseri (Turkey) was used in the start-up with a food/microorganism (F/M) ratio of about 0.15, which later changed between 0.05 and 0.2 during 170-day operation, and then increased up to 0.34 at the end of operation. This system worked throughout a 355-day operational period without any sludge extraction. The influent COD ranged between 524-983 mg L -1 during the study. Mixed liquor suspended solids (MLSS) concentration in aeration (oxic) tank of the submerged membrane bioreactor (SMBR) was changed between 3600-7400 mg L -1 during 170-day operation, and finally decreased to 2300 mg L -1 at day 355. The removal efficiency of COD was more than 99%. Influent and effluent pH values in the SMBR also changed between 7.3-8.4. © by PSP.

Turan M.,Technical University of Istanbul | Ozdemir O.,Kayseri Metropolitan Municipality | Turan A.Z.,Technical University of Istanbul | Ozkan O.,Erciyes University | And 2 more authors.
Desalination and Water Treatment | Year: 2011

A pilot-scale submerged membrane bioreactor (SMBR) with anoxic and oxic tanks was operated in an attempt to reduce the problems concerning effective removal of organic matter and nutrients from municipal wastewater. A flat type membrane with a pore size of 0.038 μm and having a total surface area of 3.60 m2 was used in the experiments. During the operation, MLSS concentration in aeration (oxic) tank of SMBR was maintained at about 5-7 g/l. Influent and effluent pH in the SMBR also changed between 7.3-8.4. Raw wastewater with average chemical oxygen demand (COD): total nitrogen (TN) ratio of 12:2 was treated at various temperatures (10-30 oC) over an interval of about 160 d. When average influent nutrient mass ratio (COD:TN:TP) was 100:8.2:1.2 and BOD5:COD ratio was 0.5, removal efficiencies of COD, BOD5, TSS, TN and TP were 99.1%, 99.3%, 99.4%, 43.4% and 68.2%, respectively. Nitrification occurred in the aerobic reactor with NH4 +-N removal efficiency ranging from 88.7 to 99.7% averaging at 97.8%. Nitrogen removal in the SMBR was limited not by nitrification but by denitrification. Increase in the concentration of TN in the treated water can be explained by increases in the concentration of NO3- -N. © 2011 Desalination Publications.

Ozkan O.,Erciyes University | Mihciokur H.,Erciyes University | Azgin S.T.,Erciyes University | Ozdemir O.,Kayseri Metropolitan Municipality
Water Science and Technology | Year: 2010

Wastewater from a medical-waste sterilisation plant (MWSP) contains unique pollutants and requires on-site treatment to prevent contamination of the municipal sewage system and receiving water bodies. Therefore, to meet the prescribed discharge standards and comply with the legal regulations, pre-treatment must be applied to MWSP wastewater. In this study, the capabilities of coagulation-flocculation processes were investigated for MWSP wastewater treatment. Processes using ferric chloride, ferrous sulfate and aluminium sulfate as coagulants were characterised. During the coagulation experiments, seven different coagulant dosages and four different pH values were evaluated to determine the optimum coagulant dosage and pH value. The highest removal efficiency of chemical oxygen demand (COD) was obtained using 300 mg/L of ferric chloride at pH 10. A COD removal of about 60% as well as considerable reductions in the amounts of suspended solids, nitrogen and phosphorus were realised. © IWA Publishing 2010.

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