Inorganic Sulfide Gaseous And Odor Emission Characteristics Of Typical Municipal Wastewater Treatment Plants

Wuxigang River and Dagang River are main rivers that flow into the west region of Taihu Lake in Yixing city, Jiangsu Province, China. With accelerated urbanization, pollutants discharged into Wuxigang River and Dagang River are annually increased. According to the general planning of water environmental quality of Taihu Lake, its quality should meet the III standard (permanganate index≤6 mg/1, NH4+-N≤1.0 mg/1 and TP<0.2 mg/1) of the environmental quality standards for surface water in China (GB 3838-2002). However, the water quality of Wuxigang River and Dagang River are far from reaching the standard of general planning.The export coefficient model was used for estimating the pollution load discharged into Wuxigang River, results showed that the total pollution load of COD,TN and TP is 77045.17 kg/a,14182.26 kg/a and 1343.08 kg/a respectively and the pollution load of COD,TN and TP discharged into Dagang River is 21159.24 kg/a,3965.16 kg/a and 486.52 kg/a respectively. Futhermore, the equivalent pollution load of different pollutants and sources were estimated, the results showed that the rural sewageis the main pollution source with the apportionment 72.58%, and followed by the large-scale livestock breeding (18.79%), planting (3.82%) and free-range breeding (3.80%) in Wuxi River. Therefore, it’s imperative to reduce the pollution load discharged into Wuxigang River and Dagang River to improve the water quality.In order to improve the water quality of Wuxi River and Dagang River, the integrated management strategies were proposed:(1) It is the key to control point-source pollution by collecting rural sewage into urban sewage pipe network and demolishing the large-scale livestock farms to improve the water quality. (2) The ecological ditches and constructed wetland are used to treat the irrigation return flow to control agricultural non-point source pollution. (3) Reduce soil erosion in the riverbank and finally improve its ecological stability with construction of ecological riverbank based on stakes combined with 3D-vegetation-net bio-stabilization technique. (4) Removal of endogenous pollutantsby ecological desalting is essential for control of endogenous pollution. By the implementation of the project, the pollution load of COD, TN and TP discharged into Wuxi river is expected to decrease by 68251.83 kg/a, 10174.24 kg/a and 1114.90 kg/a respectively and the pollution load of COD, TN and TP discharged into Wuxi river is expected to decrease by 16320.17 kg/a,2515.4 kg/a and 358.11 kg/a respectively, the water quality would reach the III standard and the total pollution load discharged intothe west region of Taihu Lake will be reduced drastically.