Study Of Carbon Fiber Carrier A~2O Process Treatting Domestic Sewage

With the promulgation of the new effluent standards, the sewage treatment plant of China will face more severe challenges. A2O process has become widely used by our country with the advantage of simple structure, short HRT and lower operation costs. As an ideal filler for microbial enrich, the new ecology carbon fiber has advantage of good biocompatibility, powerful absorption ability, non-aging and so on. The study attempts to adopt the combination of A2O process and the ecology carbon fiber, to investigate the feasibility of carbon fiber carrier A2O process for water quality upgrading from the perspective of energy conservation.In this study, carbon fiber carrier A2O process and traditional A2O process were compared to treat domestic sewage. The removal efficiencies of regular wastewater parameters were investigated between the two kinds of processes. The results showed that the wastewater treatment performance of carbon fiber carrier A2O process was better than traditional A2O processes in the condition with HRT=18h,(anaerobic4.5h, hypoxia4.5h and aerobic9h), and air water ratio=20:1. The carbon fiber carrier A2O process improved the effluent COD and ammonia from standards B to standards A. Although both processes have reached the standards A, the TN effluent of carbon fiber carrier A2O process was stable, and lower than the traditional A2O process3.5mg·L-1or more. These results showed that carbon fiber carrier A2O process had obvious advantages than traditional process in the treatment of domestic sewage.Carbon fiber carrier A2O process were used to treat domestic sewage at different reflux ratio, dissolved oxygen (DO), sludge retention time (SRT) and C/N ratio conditions. The removal efficiencies of regular domestic sewage parameters were investigated during the study period. The results showed that the best performance of the process was achieved with the reflux ratio of200%, DO of2.5mg·L1, SRT of15d and C/N ratio of10. From the perspective of energy conservation, although the effluent of the A2O process had a slight rise when the DO is2mg·L-1, it could still meet the standards A. The results showed that carbon fiber carrier A2O process could not only meet the requirements of effluent, but also achieve the purpose of energy conservation.Sludge bulking problem and the restoring way were studied by carbon fiber carrier A2O process when it was used to treat domestic sewage. Settling properties of the sludge were influenced greatly on the condition of DO which was maintained at1mg·L-1or so. SVI of the system was112mL·g-1at the beginning and rose to230mL·g-1leading to sludge bulking phenomenon. When DO in the aerobic zone increased to2mg·L-1, SVI of the system gradually restored to the original level, and sludge bulking problem was resolved.