天津市中心城区典型河道水质变化规律及污染成因分析

Analysis on water quality variation and pollution cause of typical river inTianjin central city

为实现天津市中心城区河道水环境的长效改善,以调水循环线路上的卫津河段流域为典型河道,选取八里台和纪庄子桥两个监测断面,分析NH_(3)-N、COD_(Mn)、COD_(Cr)质量浓度在年内的变化规律可知,非汛期三项指标质量浓度较低,汛期质量浓度均显著升高,严重超出地表水Ⅴ类标准。汛期泵站排水是引起河道污染物质量浓度增加的重要原因,利用系统聚类法识别引起河道断面污染物质量浓度升高的主要泵站。结果表明:八里台断面的污染物主要来源于双峰道泵站,其次为海光寺泵站;纪庄子桥断面的污染物主要来源于梅江泵站、体院北泵站和浯水道泵站。因此,在汛期应持续监测主要污染泵站的排水水质,并根据污染物质量浓度,调整泵站排水量。上述几个主要污染泵站的收水区未完全实现雨污分流,造成生活污水直接排放至河道,故落实泵站收水区域的雨污分流是改善卫津河水质的长效机制。

In order to achieve the long-term improvement of the water environment of rivers in Tianjin central urban area,taking Balitai and Jizhuangziqiao as two typical river sections in Weijin River basin in the water transfer cycling route,the concentrations of NH_(3)-N,COD_(Mn) and COD_(Cr) were analysed.The results showed that pollutant concentration in non-flood season was low,but those in flood season significantly exceeded level V of surface water standard.The drainage of pumping station in flood season is an important reason for the increase of pollutant concentration in river.Hierarchical clustering method was used to identify the main pollution source.The results showed that the main pollution source in Balitai section was Shuangfengdao pumping station,followed by Haiguangsi pumping station.The pollutants in the Jizhuangziqiao section mainly came from the Meijiang pumping station,Tiyuan Bei pumping station and Wushui Road pumping station.Therefore,it is necessary to continuously monitor the drainage quality of the main polluting pumping stations during the flood season and adjust pump station discharge.The rainwater and sewage in the water receiving areas of the above main pollution pumping stations has not been fully separated,and some domestic sewage was overflowd into the river,so rainwater and sewage diversion in the pumping station is a long-term mechanism for improving the water quality of Weijin River.