Study On Ferric Enzymatic Activated Sludge For Biological Nitrogen & Phosphorus Removal And Mechanism

Water pollution and eutrophication have become high-profile global issues, the situation of water pollution and eutrophication in China are increasingly serious in recent years, and have become the bottleneck problems that limit a rapid and steady development of our country's economy and society. High content of nitrogen and phosphorus nutrient substances in water body is the root cause of eutrophication. Therefore, Effective control of urban sewage nitrogen and phosphorus and other nutrient substances discharge is an important way to solve the eutrophication problem. The phenomenon of carbon competition between Nitrogen and phosphorus removal process restricted nitrogen and phosphorus removal efficiency.On the base of pre-existing research results, in this study, urban sewage as the research object, by conventional activated sludge contrast test, analyse the principle of ferric enzymatic activated sludge biological nitrogen and phosphorus removal from the view points of the macro perspective, microbial activity and community metabolism to reveal its reaction mechanism of biological nitrogen and phosphorus removal. And compare the effect of different external carbon source.The research results showed:(1) Under low temperatures,at start-up stage of system, the nitrification function of ferric enzymatic activated sludge restored faster than conventional activated sludge. During the steady state period, the NH₄⁺-N removal efficiencies of ferric enzymatic activated sludge and conventional activated sludge are 98.4%,97.8%, the PO₄^3--P removal efficiencies are 75.8%,45.3% and the TP removal efficiencies are 75.3%,56.3%.(2) Ferric enzymatic activated sludge have a higher stability of using different carbon source than conventional activated sludge.(3) When acetate sodium used as extra carbon source, the optimum dosage is 30 mgCOD/L,50 mg COD/L for ferric enzymatic activated sludge and conventional activated sludge, and when methanol as extra carbon source, the optimum dosage is 50 mg COD/L for both system.(4) Compared with the conventional activated sludge, dehydrogenase activity and electron transport system activity of ferric enzymatic activated sludge were respectively increased by 24.4% and 54.5%. Good correlation was demonstrated between SOUR and nitrification,the initial value of ferric enzymatic activated sludge is higher than conventional activated sludge, and the enzymatic activated sludge have a better function of nitrification.(5) The activity of microbial populations in the ferric enzymatic activated sludge system was stronger, and the metabolic is rapider. The two systems use amines as main carbon source, amino acids and carbohydrates as the second.