Discussion And Operation Of A~2/O Municipal Wastewater Treatment

Application the technology of BAWER to treat sludge water and enhanced the biological nitrogen removal, there are two main components: A2/O process (mainstream),nitrification Enrichment false continuous flow process (flow measurement).This process was aimed at the research of mainstream, preliminary study on influencing factors as temperature,SRT,DO,anaerobic residence time, C/P ratio on nitrogen and phosphorus removal. Meanwhile, the sludge recycle ratio and ORP are Discussed to explores the relationship between nitrogen and phosphorus removal. The main results are as follows:(1) When activated sludge loading is 0.21kgCOD/kgMLSS·d, the system has a good COD removal, the effluent meet the national standards. The Sludge yield is 0.25kgSS/kdCOD.(2)Temperature has great influence on nitrification. When the temperature is 20℃~ 25℃,the ammonia oxidation rate (AUR) is10.5mgNH4 N/L.H,nitrite oxidation rate (NUR) is 6.1mgNO2 N/LH,the average effluent ammonia nitrogen is 1.2mg / L. When the temperature is 15℃~ 20℃when, AUR reduced to 8.13mgNH4 N/LH, NUR reduced to 4.8mgNO2 N/LH.The average effluent ammonia nitrogen is 7.5mg / L. then SRT extended form 13d to 16d, the effluent ammonia averaged is 5.5mg / L. so extend the SRT can partially compensate for the impact of low temperature on nitrifying bacteria.(3)Aerobic zone fixed supply of oxygen and non fixed oxygen nitrification model little effect on the system, but the nitrogen removal rates were 58.2% and 49.5% on the two oxygen modes. So fixed oxygen supply mode can improve denitrification capacity.(4)Anaerobic phase hydraulic retention time increased from 0.93h to 1.89h, under the conditions of Higher nitrate content in the return sludge ,the system phosphorus removal was markedly increased. Anaerobic stage of the concentration of PO4 P increased to 1.36 compared with 4.29, PO43 P removal rate from 21.1% to 80%,TP removal increased from the 30.3% to 70.0%.(5)The nitrate content will increase in the return sludge if the sludge return ratio guide by SV30. In this experiment, the sludge return ratio guide by SV150, the nitrate content in return sludge reduced 12.2 mg / L, reduced the invalid use of the carbon source .(6)There is a certain correlation between the ORP value and anoxic nitrate. ORP value the nitrate concentration can be controlled by monitoring ORP value, to ensure the system running well. In this study, the relationship between the ORP value and anoxic nitrate is y = 39.922x 277.26.