改进型分段进水多段A/O工艺设计方法研究

Research on Design Method of Improved Step-feed Multistage A/O Biological Treatment Process

该研究为满足农村污水处理设施管理方便、能耗低的要求,针对农村生活污水碳氮比低的特点,在传统多段A/O工艺中引入生物膜,并取消首段缺氧池和污泥回流,研发了改进型分段进水多段A/O工艺。根据反硝化反应电子转移基本关系式,推导了改进型分段进水多段A/O工艺的原水流量分配关系式,进而根据等容积负荷原则确定了各级好氧池和缺氧池的容积,同时对系统脱氮率进行了预测。流量分配系数与进水C/N比值和反硝化1 g NO_3^--N所需的COD量有关。系统的理论最大脱氮率除了与这两者有关以外,还与工艺分段数正相关。通过模拟不同碳氮比生活污水的连续运行实验,表明理论模型可以很好地指导工艺设计。进水COD/TKN分别为3.75和7时,系统TN平均去除率分别为50.5%和60.0%,出水能够稳定达到《城镇污水处理厂污染物排放标准》一级B标准。

Thisstudy developed improved step-feed multistage A/O biological treatment process. Biofilm was introduced to this improved process and the recirculation in tradition step-feed A/O biological treatment process was left out. The improvement adapted to low C/N ratio of rural domestic wastewater andmet the needs of convenient maintenance and management as well as low operating cost.According to the basic relations of electron transfer in denitrification reaction,the formula of influent flow distribution of the improved step-feed multistage A/O biological treatment process was derived. The volume of every aeration and anaerobic pool was determined basing on principle of equal volumetric loading rate. Nitrogen removal rate of processing treatment would be predicted. The flow distribution ratio was related to C/Nratio of influent and the COD contents demanded by denitrification. However,the maximumnitrogen removal efficiency of the biological treatment system was also related to the numberof process segments in addition to the above mentioned. The more segments,the higher nitrogenremoval rate theoretically.The improved step-feed process was incessantly operated using the studied method of influent flow distribution with synthetic wastewater in different C/N ratio. The results showed that theoretical model could guide process design effectively and the improved process had the advantages of resistance to shock loading as well as convenient maintenance and management. The TN removal rates were 50.5% and 60% on average,respectively,when CON/TKN ratios of influent were set at 3.75 and 7,with the effluent satisfactory to Grade I-B criteria of GB 18918-2002 steadily.