Research on water environmental quality evaluation and characteristics analysis of TongHui River

This study evaluated water quality of TongHui River in Beijing based on the fuzzy mathematics comprehensive evaluation model and the spatial cluster analysis, according to the measured data, seven evaluation parameters were chosen: dissolved oxygen, total nitrogen (TN), total carbon(TC), chemical oxygen demand (COD), ammonia nitrogen, nitrate nitrogen and total phosphorus (TP). The fuzzy comprehensive evaluation results show that: water quality of sample point 15, 8, 9 (GaoBeiDian sewage treatment plant), 19 and 5 is good, water quality of sampling 10, 11 (sewage outfalls), 1, 2, and 3 (south channel) is bad. Because of GaoBeiDian reclaimed water supply place, water quality of sampling 8 and 9 is improving; TN and TP were reduced by 30% and 9.7%. But the whole river water quality still lower than the national fifth kinds of water quality. Hierarchical clustering analysis results show that: the distribution of TongHui River is obviously spatial, water conditions can be divided into three groups: A class represents mild pollution is mainly distributed in DaWangLu, YongAnLi, etc, near which factories, printers, water pollution and central business district (CBD),water quality is general. Class B represents moderate pollution, it located downstream of C kind, Contaminated influence of polluted water, water quality is poorer; C kind is dirtiest for pollutant discharges. Results of evaluation and hierarchical analysis provides scientific basis for water pollution management and control.