微丝菌型污泥膨胀的工艺负荷调控方法

提出调控工艺局部污泥负荷分布来处理污水处理厂冬季微丝菌污泥膨胀。在某AAO工艺污水处理厂开展平行反应器实验，进行显微观测和工艺模拟，发现反应器前端厌/缺氧区污泥去除负荷的差值与微丝菌丰度、污泥粒径和沉降性能有相关性。比较多种运行模式的改善效果，发现AO模式沉降性能最好，优于AAO和多点回流。反应器前端污泥去除负荷梯度可作为调控指标，实验中AO模式负荷梯度可达0.54 kg COD·（kg SS·d）-1，明显高于AAO、多点回流和多点进水。因此，通过优化回流和排泥操作，可以调控污泥去除负荷的沿程分布，有可能缓解冬季的微丝菌型污泥膨胀。

Optimizing process loading rates to control activated sludge bulking by Microthrix parvicella

In this paper, we investigated a method to control Microthrix parvicella bulking in municipal wastewater treatment plants (WWTPs) during the winter season, by optimizing the profile of removal loading rates by sludge (Lsr) along the process steps. We conducted parallel experiments and process modeling at a WWTP with anaerobic-anoxic-oxic (AAO) process in northern China, in order to understand the dynamics of sludge bulking by M. parvicella. As the results, we found that the Lsr values were correlated with the filamentous bacteria amount, the floc size, and the settling property of activated sludge. By comparing different process running modes, we found that the inhibition of bulking in the anoxic-oxic (AO) mode was the best among the AAO, AO and multiple return sludge modes. We selected the difference of Lsr in the first two reactors as control variable for sludge bulking, which in AO mode was 0.54 kg COD·(kg SS·d)-1, much higher than that in other modes like AAO. The experimental data proved that the AO mode was helpful for dealing with sludge bulking caused by low influent loading, in which the sludge flows generated the highest difference of local Lsr in the bioreactors.