Pollutant Discharge Loads In Tiaoxi Inlet Of Taihu Lake

Tiaoxi River is one of the main inflow rivers around Taihu. Based on the census sources data of pollution, monitoring data on the water quality and water quantity about the lake inlet of Tiaoxi, the pollutant discharge quantity was calculated as well as the inflow and outflow water quality and water quantity of Tiaoxi were analyzed to calculate the pollutant fluxes. Tiaoxi basin's coupling model of water quality and water quantity was applied to simulate the inflow and outflow water quality and water quantity of Tiaoxi in different hydrologieal years and the effect of water quality through measures for the lake inlet of Tiaoxi's emission reduction in hand. The results showed the importance of waste reduction in this area and could provide supporting data for both Tiaoxi and Taihu basins'water pollution control. The main content and conclusion were given below.1. Based on the census sources data of pollution in 2008, the pollutant discharge quantity of CODMn, NH3-N, TP and TN from industrial source, town living source, livestock breeding source, aquaculture source, rural living source and farmland runoff source in the lake inlet of Tiaoxi were calculated. It is shown that the annual pollutant discharge quantities in the lake inlet of Tiaoxi were CODCr 27965.21t/a, NH3-N 1550.81 t/a, TP 270.63t/a, TN 2742.96t/a. The emissions per unit area in near-lake place were highest which were chiefly from town living source. The emissions per unit area in buffer zone were mainly from rural living source and farmland runoff source. There was no pollution source in the lakeside.2. Based on the monitoring data on the water quality of three main rivers round Taihu Lake(Xiao-mei Gang, Chang-dou Gang and Da-qian Gang) and on the water quantity of two staff gauge stations of Tiaoxi (Yang-jia Bu and Hang-chang Qiao) during 2005-2010, the water quality and water quantity of Tiaoxi were analyzed and Tiaoxi inflow rivers'pollutant fluxes of CODMn, NH3-N, TP and TN were calculated. The results showed that the water standard of each river was Class III and the chief contaminant was TN. During 2005-2010, the water quantity from Tiaoxi to Taihu Lake was 9.15×108～17.85×108m3 while which from Taihu to Tiaoxi was 11.52×108～15.28×１08m3. The pollutant flux of TN was relatively high, whose average pollutant flux was 3400t/a.3. Tiaoxi basin's coupling model of water quality and water quantity was applied to simulate Tiaoxi's pollutant fluxes on different hydrological years as well as the water quality improvement through Poluution Reduction and Aquatic Ecological Restoration Project and Experimental Project in the lake inlet of Tiaoxi. It was shown that the simulated pollutant loads varied in different rainfall probability and Poluution Reduction and Aquatic Ecological Restoration Project made little contribution to inflowing water quality mend, whereas Experimental Project could achieve about 8% of water quality improving effect.