FILTRATION OF HEAVILY-POLLUTED INFLOW RIVERS OF NANSI LAKE AND WATER ENVIRONMENTAL PROBLEMS ANALYSIS

Based on monitoring data of spatial distribution of water quality in main inflow estuary of Nansi Lake,according to the standard of average comprehensive pollution index Pj2,17 heavily-polluted rivers such as Guang Fu river and Xuecheng Xiaosha River etc.were selected.The average value of individual soiled contribution rates of CODcr,TP,TN of these rivers were 45.5%,76.3%,86.4% respectively,indicating that TN and TP in Nansi lake were mainly from the heavily-polluted rivers.The average value of individual soiled share rates of CODcr,TP,TN were 22.7%,15.4%,61.9% respectively,indicating that the primary pollutant in Nansi Lake was TN,and the following were CODcr and TP.The paper gave the linear regression equations of NH3-N and TN in inflow estuary of east Nansi Lake.Affected by topography,river morphology,hydraulic retention period as well as pH,SS,chlorophyll-a and other factors in water of the west and east lake,the nitrification processes of rivers in the west lake are better than those in the east lake,and the average ratio of NH3-N and TN in inflow estuary of west and east Nansi lake were 0.25 and 0.65 respectively.The result showed that,the catchment areas of heavily-polluted rivers generally distribute in major towns and industry and mine areas,CODcr and nitrogen pollutants were mainly from point pollution sources such as industry and urban life,and phosphorus pollutants were mainly from part of the industry.Therefore,the highest priority is to strengthen control measures of point sources such as industrial structure adjustment,emphasize enterprise cutting down pollution as well as remove nitrogen and phosphorus in municipal waste water treatment plant in Nansi Lake basin.