多级A/O-MBR工艺对生活污水脱氮除磷的工艺研究

Study on Multistage A/O-MBR Process for Nitrogen and Phosphorus Removal from Domestic Sewage

针对传统A2/O工艺难以实现对生活污水高效脱氮除磷的问题,在传统的A2/O工艺的基础上,增加膜生物反应器,构建多级多段A/O-MBR工艺中试实验设备,考察该系统的反应级数和进水分配方式对生活污水脱氮除磷的影响。该系统分别以厌氧区单点进水的三级A/O工艺、以50%、22.70%、18.30%和9%比例进水的四级A/O工艺和以55%、30%和15%比例进水的三级A/O工艺三种工艺运行,实验结果表明,当进水COD、TN、NH3-N和TP平均质量浓度分别为258.31、27.50、17.20、2.77 mg/L时,以55%、30%和15%比例进水的三级A/O工艺系统的水处理效果最好,其出水COD、NH3-N、TN和TP平均质量浓度是21.20、0.48、4.11、0.51 mg/L,平均去除率为90.26%、96.88%、81.88%和76.45%,出水COD和NH3-N质量浓度均达地表水环境质量标准(GB 3838-2002)Ⅳ类水体标准,出水TN浓度都达到城镇污水处理污染物排放标准(GB 18919-2002)一级A标准,出水TP中有64.29%达到一级A标准,各功能单元COD、NH3-N、TN和TP负荷分配合理,合理利用碳源。该多点进水三级A/O-MBR工艺实现了污水中碳源的有效利用和较低水处理成本。

Aimed at the problem of traditional A2/O process is difficult to achieve high-efficiency nitrogen and phosphorus removal from domestic sewage, a pilot-scale multi-stage A/O-MBR process was constructed by adding a membrane bioreactor on the basis of traditional A2/O process, and the effects of the reaction order and the formula of water intake on nitrogen and phosphorus removal from domestic sewage were investigated.The system was operated by three stages of A/O process with single point feed water in anaerobic zone, four stages of A/O process with 50%, 22.70%, 18.30% and9% proportion feed water, and three stages of A/O process with 55%, 30% and 15% proportion feed water, respectively.The experimental results showed that when the average concentrations of COD, NH3-N, TN and TP in influent were 258.31 mg/L, 27.50 mg/L, 17.20 mg/Land 2.77 mg/L respectively, the three-stage A/O process system with 55%, 30% and 15% feed waterhad the best water treatment effect.The average concentrations of COD, NH3-N, TN and TP in effluent were 21.20 mg/L, 0.48 mg/L, 4.11 mg/L and 0.51 mg/L respectivelyand the average removal rates were 90.26%,96.88%, 81.88% and 76.45%respectively.The concentration of COD and NH3-N in effluent both reached the Class IV water body standard of Surface Water Environmental Quality Standard(GB3838-2002), and the concentration of TN in effluent all reached the Class A standard of Urban Sewage Treatment Pollutant Discharge Standard(GB18919-2002). 64.29% of the effluent TP reached the first-class A standard, and the distribution of COD,NH3-N, TN and TP of each functional unit was reasonable, and the carbon source was rationally utilized.The load distribution of COD, NH3-N, TN and TP of each functional unit was reasonable, and the carbon source was rationally utilized. The multi-point influent three-stage A/O-MBR process achieved efficient use of carbon sources in sewage and lower water treatment costs.