城市污水短程硝化的控制策略及对污泥种群的影响

Optimizing nitrifying community and achieving partial nitrification with real-time control

采用有效容积为54m^3的大型中试序批式活性污泥处理（SBR）反应器,研究了在常温下处理碳氮比（C/N）平均值为2.16的以生活污水为主的实际城市污水时短程硝化的实现和稳定问题。试验结果表明,采用分段进水的运行模式,使出水总氮（TN）达到了小于3mg/L的深度脱氮效果。同时通过对SBR反应阶段的实时控制,优化了污泥种群结构,从而实现了温度为12-26℃、平均溶解氧（DO）浓度在2.5mg/L以上的环境条件下长期稳定的短程硝化反硝化,系统维持95%以上的亚硝化率稳定运行180天以上。应用荧光原位杂交（FISH）技术对系统中的氨氧化菌（AOB）和亚硝酸盐氧化菌（NOB）的数量进行了分析,结果也证明了系统中氨氧化菌在硝化菌中占绝对优势,亚硝酸盐氧化菌已逐步被淘汰。

A pilot-plant sequencing batch reactor （SBR） with a working volume of 54m^3 was used in the experiment on biological nitrogen removal via nitrite from municipal wastewater with 16w COD/N ratio for saving energy and carbon sources. At normal water temperature, the feasibility of achieving and stabilizing nitrogen removal via nitrite from municipal wastewater with the low COD/N ratio （ average 2.16） was investigated. The obtained resulted showed that the total nitrogen （TN） in the effluent was less than 3mg/L and the advanced nitrogen removal was obtained through application of stepfeed operation. Moreover, by using the real-time control strategies, the nitrifying communities were optimized. Thus, under normal dissolved oxygen （DO） condition, nitrogen removal via nitrite was successfully achieved at the range of temperature between 12℃ to 26℃. Nitrogen removal via nitrite kept the long-term stability （ 180 days） and the average NO2- N/NOx-N ratio was above 95 %. The fluorescence in situ hybridization （FISH） was performed to analyze the quantitative changes of nitrifying microbial communities in the activated sludge. The results also indicated that ammonia-oxidizing bacteria （AOB） became the dominant nitrifying bacteria and nitrite-oxidizing bacteria （NOB） had been washed out of the activated sludge. It indicated that the nitrifying microbial communities were optimized.