改良分段进水工艺处理低C/N城市污水流量优化控制

采用改良分段进水工艺处理低碳氮比(C/N3.5)生活污水,研究流量分配对系统处理性能的影响。在其他条件不变的情况下,以实际处理效果以及物料衡算结果为依据来逐步提高首段进水比例以寻求最优的流量运行工况,共确定4组不同的进水流量分配。结果表明:在此碳氮比条件下,通过提高首段进水比例的方法并不能降低厌氧区氮氧化物的含量,甚至出现相反的情况;系统的同步硝化反硝化作用以及微生物同化作用强度对TN的去除起着至关重要的作用;首段进水比例的提高强化了厌氧区聚磷菌的释磷作用,提高了磷酸盐的去除率;综合考虑系统的脱氮除磷效能以及后续可优化空间,确定在进水流量分配比例为6:3:1的工况3为最优工况,系统出水COD、氨氮、总氮、磷酸盐浓度分别为45.98、0.04、17.47和2.43 mg·L-1。

Optimization of flow for modified step feed process treating low COD/TN municipal sewage

By adjusting the distribution ratio of influent flow into anaerobic and anoxic zones, the removal efficiency of pollutants in low C/N(COD/total nitrogen)<3.5 municipal sewage using modified step feed process was analyzed. Keeping the following conditions unchanged: hydraulic retention time (HRT) 10 h, sludge retention time (SRT) 10-15 d, volume of anaerobic zone:volume of total anoxic zones:volume of total aerobic zones 4:9:9, when the actual efficiency obtained and material balance calculation results were utilized to increase gradually the water ratio distributing to the first stage i.e. anaerobic zone, the best operating conditions could be found and 4 kinds of operating conditions determined. The results show that, at given C/N ratio, concentration of nitrogen oxides in anaerobic zone does not decrease with the increase of the water ratio entered into anaerobic zone, even appears the opposite situation. The simultaneous nitrification and denitrification(SND)and microbial assimilation effect intensity play crucial role in TN removal. The rise of water ratio entered into anaerobic zone improves the removal rate of phosphate due to the phosphorus release effect of phosphorus-accumulating bacteria is enhanced in anaerobic zone. Both nitrogen and phosphorus removals as well as subsequent optimization space are considered, one of optimized water distribution ratio is 6:3:1,and at this condition, the effluent concentration of COD, ammonia nitrogen, TN, phosphate is 45.98, 0.04,17.47 and 2.43 mg·L^-1 respectively.