[Characteristics and loads of key sources of pollutions discharged into Beishi River, Changzhou City].

Choosing the Beishi river,Changzhou City as the study area,the sewage generation,pollutants characteristics and sewage discharge in catchment area of Beishi river were conducted,detailed investigated and monitored.After using pollution coefficients,the yearly loads of all sources of pollutions were calculated to determine the highest sewage.The results showed that:except pH,the high concentration of SS,COD,BOD5,ammonia nitrogen,TN and TP discharged from MSW collecting houses,MSW transfer stations,public toilets and dining in Changzhou city far exceeded the "Integrated Wastewater Discharge Standard"(GB 8978-1996) and "Effluent Discharged into the City Sewer Water Quality Standards"(CJ 3082-1999).Among which:the highest concentration of COD discharged from MSW transfer stations was up to 51 700 mg /L,while the ammonia nitrogen and TN were as high as 1 616 mg /L and 2 044 mg /L in the toilet wastewater.In addition to this,the ratio of wastewater discharged directly into the river through storm water pipe network was higher from MSW houses,MSW transfer stations,public toilets,dining and other waste in Changzhou city.The 125.2 t /a of COD and 40.53 t /a of BOD5 were the two highest concentrations of various sources of pollution.The highest annual polluting loads discharged into Beishi river is dining,followed by the sanitation facilities.Therefore,cutting pollution control of food and sanitation facilities along the river is particularly urgent.