环境敏感地区城市污水处理厂超深度除磷运行现状及潜力分析

Analysis of ultra advanced phosphorus removal situation and potential in municipal wastewater treatment plants in environmentally sensitive area

以环境敏感地区的4座城市污水处理厂为研究对象,对其进出水常规指标和磷组分进行取样检测和统计分析。结果表明4座污水处理厂的进水水质差异较大,但出水水质指标均达到GB 18918-2002一级A标准,进一步对磷组分分析发现,各污水处理厂磷素与进水COD和SS的相关性差异较大,但4座污水处理厂进水和出水中的磷主要以溶解性正磷酸盐和悬浮态磷为主,总和占比分别超过了93%和88%。在深度除磷试验中发现,采用两次分段投加PAC的除磷效果明显好于单次投加PAC,两段投加的比例为50/50时,除磷效果最优。生产线的PAC投加应关注PAC投加量与进水总磷质量浓度的比值(M_(c)/M_(0)),常规情况下M_(c)/M_(0)值在30~40内能够有效的保障出水TP低于0.05 mg/L,如果进水TP较高和波动范围较大时,M_(c)/M_(0)值也需进一步加大,来保障出水TP低于0.05 mg/L。

Four municipal wastewater treatment plants in environmentally sensitive area were studied,and their influent and effluent conventional indicators and phosphorus compositions were tested and statistically analyzed.The results showed that the influent quality of these four WWTPs was significantly different,but the effluent quality indices of all these four WWTPs could reach the first-class A standard.Further analysis at the phosphorus composition found that the correlations between phosphorus and COD and SS of influent in each WWTP were quite different.However,the dissolved phosphorus and suspended phosphorus were the main components in total phosphorus of these four WWTPs'influent and effluent,accounting for more than 93%and 88%,respectively.In the advanced phosphorus removal experiment,it was found that the phosphorus removal effect of adding PAC in two stages was significantly better than that of a single addition of PAC.When the ratio of two stages of adding PAC was 50/50,the phosphorus removal effect was the best.When adding PAC in the production line,attention should be paid to the ratio of PAC dosage to the mass concentration of total phosphorus in the influent water(M_(c)/M_(0)).Under normal circumstances,the value of M_(c)/M_(0) within the range of 30~40 could effectively ensure that the effluent TP was lower than O.05 mg/L.However,if the influent TP was high and the fluctuation range was large,the value of M_(c)/M_(0) needed to be further increased to ensure that the effluent TP is lower than 0.05 mg/L.