同步化学除磷对A2/O工艺除污染效能与活性污泥性能的影响

考察了A2/O同步化学除磷工艺中Al2（SO4）3投加量对TP、COD、NH4+-N和TN的去除率与活性污泥性能的影响。结果表明，常温（18~32℃）条件下同步化学除磷最适宜的Al2（SO4）3投加量为铝、磷摩尔比0.5：1，此条件下出水TP、COD、NH4+-N和TN浓度均能达到《城镇污水处理厂污染物排放标准》（GB 18918-2002）一级A标准。研究同时发现，Al2（SO4）3投加后，活性污泥的沉降性能和污泥活性均有所增强，其中SVI值由93.8 mL·g-1降至81.3 mL·g-1，Zeta电位由-5.5 mV降至-11.8 mV，胞外聚合物EPS含量增加了59.9%，蛋白质与多糖的比例由5.2降至2.1，比耗氧速率由4.2 mg·（g·min）-1升高到6.7 mg·（g·min）-1（以MLSS计）。微生物菌群结构分析结果表明，投药后污泥中微生物种类由投药前的8种减少为6种，硝化菌和反硝化菌比例有所降低，聚磷菌比例升高为6%。在低温（0~10℃）条件下，Al2（SO4）3投加量需有所增加，当铝、磷摩尔比为1：1时，反应器出水TP、COD、TN和NH4+-N浓度方可达到一级A标准。

Effect of simultaneous chemical phosphorus removal on contaminant removal efficiency and activated sludge characteristics in A2/O process

In this study, we investigated the effects of different Al2(SO4)3 levels on the removal efficiencies of TP, COD, TN, and NH4+-N. We also examined the activated sludge characteristics with the simultaneous chemical phosphorus removal in the A2/O process. The optimal molar ratio of P-to-Al was 0.5:1 under normal temperature conditions(from 18 to 32℃)and the concentrations of TP, COD, TN, and NH4+-N in the effluent met the first grade A Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). The results of the analysis of the activated sludge characteristics in the aerobic treatment unit showed that the sedimentation performance and the activity of sludge were strengthened and the values of SVI and Zeta potential reduced from 93.8 mL·g-1 to 81.3 mL·g-1 and from -5.5 mV to -11.8 mV, respectively. The amounts of Extracellular Polymeric Substances increased by 59.9%, the ratio of protein-to-polysaccharide reduced from 5.2 to 2.1, and the oxygen uptake rate increased from 4.2 mg·(g·min)-1 to 6.7 mg· (g·min)-1 (MLSS)The results of the microorganism community structure analysis showed that microbial species reduced from 8 to 6 after Al2(SO4)3 application. Nitrifying bacteria and denitrifying bacteria ratios decreased while the phosphorus-accumulating organism ratio reached 6%. Under low temperature conditions(from 18 to 32℃)and at the molar ratio of P-to-Al of 1:1, the Al2(SO4)3 dosage should be increased so that the concentrations of TP, COD, TN, and NH4+-N in the effluent could meet the first-grade A standards.