污泥负荷对UASB处理低浓度污水运行效果和污泥性质的影响

采用升流式厌氧污泥床（UASB）反应器处理低浓度生活污水，探讨了不同污泥负荷对运行效果及污泥性质的影响。通过考察有机物去除率、有机酸积累、污泥粒径、污泥比产甲烷活性、溶解性微生物产物（SMP）、胞外聚合物（EPS）等生化指标，得出如下结论：在受试条件下，污泥负荷率的升高不利于有机物的去除；有机酸特别是乙酸的积累，以及受基质缺乏及污泥洗脱限制的污泥积累，是影响处理效果的因素；稳定阶段污泥的胞外聚合物以紧密附着型EPS为主，污泥负荷升高将导致其浓度升高，而对SMP和松散附着型EPS没有显著影响，EPS的浓度及其组成不影响污泥性质。高的污泥负荷下污泥的产甲烷活性较高。在本实验中，F/M=0.4 g COD/（g MLSS·d）是最佳的污泥负荷条件。

Effect of sludge loading on process performance and sludge properties of UASB treating low-strength municipal wastewater

Up-flow anaerobic sludge blanket (UASB) reactors were applied in low-strength wastewater treatment, aiming at investigating the impacts of sludge loading on process performance and sludge properties in this study. Various biochemical indicators were monitored, such as the removal of organic substances, the accumulation of organic acid, sludge particle size, specific methanogenic activity, soluble microbial products (SMP), extracellular polymeric substances (EPS).We find that the increase of sludge loading negatively affects the organic removal in the process. Two main reasons accounting for the unsatisfied performance, the accumulation of organic acid, esp. the acetic acid, and the sludge accumulation restricted by insufficient substrate and sludge washout. The tightly-bound EPS dominates the EPS of sludge in the stable stage, and increases with sludge loading increasing. In contrast, there is no significant impacts of sludge loading on the SMP or the loosely-bound EPS. The content and constitutions of EPS have no effect on sludge properties. The sludge loading positively affects the specific methanogenic activities of sludge. In this study, the optimal F/M ratio is 0.4 g COD/(g MLSS·d).