长江大保护试点城市某污水处理厂尾水湿地净化效果研究

Decontamination effect of tail water wetland accompanying the sewage treatment plant-A case in the area of the Yangtze River Grand Protection

为探寻污水处理厂配套尾水湿地净化效果,以长江大保护试点城市某污水处理厂尾水湿地为例,通过现场调查与采样,分析湿地出水水质特征,探讨影响湿地污染物去除效率因素。结果表明:尾水湿地出水COD、NH_(3)-N及TP浓度满足设计目标,潜流湿地对COD去除率较高,表流湿地对氨氮及磷的去除率较高,优于涵养塘;湿地实际运行水力负荷、水力停留时间和污染物负荷与设计值不符,影响污染物去除效果;据此提出湿地运行优化建议,促进湿地深度脱氮除磷,提升尾水湿地效能;运行优化可提高潜流湿地污染物去除率,同时污水处理厂减少碳排放94.74 gCO_(2)m^(3)。研究结果可为该尾水湿地运行管理及长江大保护试点城市系列污水处理厂配套尾水湿地设计与运维提供参考。

In order to explore the effect of the tail water wetlands accompanying the wastewater treatment plants,a constructed wetland system of the municipal sewage plant located in the area of the Yangtze River Grand Protection was taken as a case study.The quality of the effluent water from the constructed wetland system and the factors affecting pollutant removal efficiency were discussed through field investigation and sampling analysis.The results show that the concentrations of the chemical oxygen demand(COD),ammonia(NH_(3)-N)and total phosphorus(TP)of the effluent water from the wetlands meet the requirements of the design object.The submerged wetland had a higher removal rate of COD,whereas the surface flow wetland had a higher removal rate of ammonia and phosphorus,both higher than those of the self-restrained ecological pond.The present hydraulic loads,hydraulic retention time and pollutant loads had not matched the design parameters,which had impact on the pollutants removal rates.Accordingly,the optimization suggestions were proposed for the tail water wetland,which could improve the pollutant removal rate of the submerged wetlands,while the wastewater treatment plant can reduce carbon emissions by about 94.74 gCO_(2) m^(3).The results can provide reference for the operation and management of the tail water wetland system,and for the design,operation and maintenance of the series tail water wetlands cases in the areas where the Yangtze River Protection actions are carried out.