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Chen W.,Hohai University | Wu D.,Hohai University | Zhu N.-W.,Hohai University | Zheng X.-Y.,Hohai University | And 2 more authors.
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2010

By combining the membrane bioreactor of the PVDF hollow fiber membrane with the A/A/O process, a pilot test system of A/A/O-membrane process (A/A/O-MBR) was constructed and employed in treating municipal wastewater in Taihu Lake Basin. According to the nitrogen removal of combined process, the nitrification rate of activated sludge in MBR was studied. The effect of dissolved oxygen concentration, influent ammonia nitrogen concentration and temperature on nitrification rate was analyzed. It is found that the average removal rates of ammonia nitrogen of combined process are 96.56% and 96.68% in summer and winter, respectively. Influent ammonia concentration has little effect on nitrification rate at low temperature of less than 15.0°C. Higher temperatures would speed up the nitrification rate and the nitrification rate of combined process at 30.5°C was 2.6 times than that at 11.8°C. Compared with the conventional process, nitrification rate of combined process was 2.3 times than that in oxidation ditch. The enhanced nitrification of long hydraulic retention time formed by two nitrification phase and the role of membrane filtration in MBR offset the inhibitory effects of low temperature on nitrification rate.

He Y.,Hohai University | Chen W.,Hohai University | Zheng X.,Hohai University | Zhang Y.,Wuxi Drainage Management Office | And 3 more authors.
Journal of Hohai University | Year: 2012

High-concentration aromatic tobacco flavor wastewater was pretreated with Fenton reagent and PAM coagulation, and the optimal operating conditions of the method, including the optimal reaction time and reagent dosing sequence and dosage were determined. The results show the following: (a) The Fenton regent oxidation and coagulation method is an effective measure for pretreatment of high-concentration aromatic tobacco flavor wastewater. The COD removal rate was 79.6% and the wastewater was completely clarified after pretreatment with the Fenton reagent, PAM coagulation, and pH regulation, (b) The optimal operating conditions of the method were as follows: 45 g/L of FeSO4·7H2O and 150 mL/L of H2O2 were initially added to the wastewater, and after 60 minutes' reaction, they were treated by PAM coagulation for 10 minutes. Finally, the pH value was adjusted to 7 with NaOH.

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