低DO下曝气方式对分段进水脱氮工艺的影响

采用分段进水生物脱氮工艺处理小区生活污水，考察了在低DO条件下，不同曝气方式对硝化率及污泥沉降性能的影响。结果表明，在曝气量为0．27m^3／h、MLSS平均为2700mg／L左右、好氧区的DO为0．26～2．5mg／L的条件下，当进水氨氮为44～55mg／L时，对氨氮的去除率保持在95％以上，对COD的去除率〉90％；当控制好氧区第1、2格室的DO分别为0．5～0．7和1．0～1．2mg／L时，系统的硝化率维持在90％以上，出水中的氨氮〈2mg／L；在恒定曝气量下，向进水中投加有机碳源，当水质改变较快时，容易引起丝状菌污泥膨胀，但通过恒DO曝气控制，可使污泥的沉降性能得到改善。

Effect of Aeration Mode on Step-feed Biological Nitrogen Removal Process under Low DO Condition

The lab-scale step-feed biological nitrogen removal process was used to treat domestic sewage, and the effect of different aeration modes on nitration rate and sludge settleability was investigated under low DO condition. The results show that the removal efficiencies of ammonia nitrogen and COD are more than 95% and 90% respectively when the aeration rate is 0.27 m^3/h, the MLSS averages 2 700 mg/L, the DO in aerobic zone is 0.26 to 2.5 mg/L, the innuent ammonia nitrogen concentration is 44 to 55 mg/L. The nitration rate keeps at above 90% , and the effluent ammonia nitrogen is below 2 mg/L when the DO in chambers 1 and 2 of aerobic zone is 0.5 to 0.7 mg/L and 1.0 to 1.2 mg/L respectively. At constant aeration rate, the adding of organic carbon sources to wastewater can cause filamentous sludge bulking when the wastewater quality fluctuates rapidly. However, the constant control of DO aeration can improve sludge settleability.