Simulative Computation of Water Quality in Sewage Treatment Projects of Plain River Network

Cixi City is located on the plain river network region of economically prosperous Northern Zhejiang.Before 2006,large quantities of industrial waste water and a majority of untreated urban and township sewage were discharged into the Hangzhou Bay through the river network,causing heavy pollution in rivers and sea.The sewage treatment project of the city has been undertaken by expanding regional pipe network and sewage treatment capacity,as well as by enlarging water supply capacity.With a 1-D water environment numerical model and verification,this study simulated the change in CODMn of water quality before and after the implementation of such project,providing reliable results for environmental impact evaluation.