Study On Biological Nitrogen And Biological Phosphorus Removal With Activated Sludge-Biofilm Integrative Reactior

With the aggravating of water entrophication pollution,the design of municipal wastewater treatment process must consider phosphorus removal and nitrogen removal. But as far as the level of the technology,economy,management and limited ground in China is concerned,it is urgent to develop a simple,high-efficient and low-consumptive biological phosphorus and nitrogen removal system correspond to the situation of China. The Activated Sludge –Biofilm Integrative Reactor(ASBIR ) is developed in ordered to settle the above problems. The ASBIR is consisted of anoxic area,oxic area and settling area and the scutellate carrier is added in the oxic area to attain a good effect of biological phosphorus and biological nitrogen removal by combining biofilm and activated sludge process. The aim of study in the dissertation is to find reasonable operating parameters and operating condition for the ASBIR to make the effluent quality meet the Grade I of National Discharge Standards(GB 18918-2002). The six operating conditions are studied in one year:(1) Dissolved Oxygen (DO) single factor experiment. (2) Hydraulic Retention Time(HRT) single factor experiment. (3) ratio of returned sludge single factor experiment. (4) Sludge Retention Time(SRT) single factor experiment. (5) water temperature single factor experiment. (6) sludge loading single factor experiment. It is discovered by the six single factor experiments: the effluent concentration of COD and total phosphorus(TP) can reach the Grade I of National Discharge Standards(GB 18918-2002) when the operating parameters are arranged reasonably,but the effluent concentration of NH4+-N and total nitrogen(TN) can't meet the GB 18918-2002. The test results of domestic wastewater treatment showed that the BASIR has a high ability of COD and TP removal and can remove NH4+-N and TN at the same time. It is obvious that the ASBIR has the advantage of less land area,low construction investment because of the integration of anoxic area, oxic area and settling area. what's more , low energy consumption and convenient management are the ASBIR's advantages because the mixed liquid return system and sludge return system are combined into one system.Therefore,the ASBIR can be widely used in small town after it is further improved.