Experimental Research On Enhanced Nitrogen And Phosphorus Removal Of Municipal Sewage By Composite Ferric Enzymatic Activity Sludge

From 1960's, water wutrophication has focused by people all over the world,controling and treating nitrogen and phosphorus pollution is the essential way to cure it. The existing wastewater biological nitrogen and phosphorus removal technology has the problems of lower nitrogen and phosphorus removal efficiency, poorer operational stability and more difficult nitrification in low temperature. According to ferric enzymatic activated sludge biological nitrogen and phosphorus removal technology, in order to solve contradictions and difficult problem of composite ferric enzymatic activated sludge system(CFEASS), a typical sewage treatment plant was choosed to carry out experimental research on enhanced nitrogen and phosphopus removal of municipal sewage by composite ferric enzymatic activity sludge. The main contents and results are as follows:(1) The results of operation effect of nitrogen and phosphorus removal of CFEASS and comparison system(CS) showed that on the condition of 16～19℃,HRT=15h,SRT=40d,COD of effluents from CFEASS and CS was 41mg/L,58mg/L,NH₄⁺-N of effluents from CFEASS and CS was 2.36mg/L,6.27mg/L,PO₄^3--P of effluents from CFEASS and CS was 1.06mg/L, 1.96mg/L.COD,ammonia and phosphate removal efficiencies of CFEASS were 6%, 12.2%, 33.9% higher than that of CS. Under the condition of 16～19℃and 22～27℃,COD,ammonia and phosphate removal efficiencies of CFEASS were 2%, 8.4%, 23.7% and 3%, 3.7%, 4.1% higher than that of CS.(2) The results of contrasting experiment research on reaction process of biological nitrogen and phosphorus removal and microbial activity of two activated sludge systems in normal temperature showed that specific nitrification rate of CFEASS and CS was 4.985 mg NH₄⁺-N/ ( g·MLVSS·h ) ,3.563mg NH₄⁺-N/(g·MLVSS·h).Specific nitrification rate of CFEASS is 28.5% higher than that of CS in the first 30min of nitrification. In the 0³0,30⁶0,60⁹0min of aerobic stage, the average specific oxygen uptake rate (SOUR) of CFEASS was 23.6%,32.6%,30.2% higher than that of CS.To some extent,CFEASS improved microbial activity and strengthened treatment effect of N and P.(3) The results of biological nitrogen and phosphorus removal influenced by environmental factors changes of CFEASS and CS showed that during low dissolved oxygen, NH₄⁺-N removal efficiencies of two systems gradually decreased.In recovery,restoration of nitrification of CFEASS was more quickly.Under low temperature(11～16℃) .Ammonia and phosphate removal efficiencies of CFEASS were 9.8% and 20.3% higher than that of CS. CFEASS had more powerful anti-cold capability. It has important significance on improving nitrification at low-temperature conditions.The innovativeness of ferric enzymatic activated sludge biological nitrogen and phosphorus removal technology is through ferric ion getting involved into microbial biochemical reactions and energy metabolism, strengthen ferric ion participate in the electron transfer and the role of enzymatic reaction activator to enhance biological nitrogen and phosphorus removal efficiency, and resolve the inherent contradictions and bottlenecks of biological nitrogen and phosphorus removal systems from the source, provide a new idea for the development of efficient deep nitrogen and phosphorus removal technology.