关键词: 污水超标排放, 水质数值模拟, 水环境影响, 长江口

Abstract: To analyze the impact of excessive sewage discharge on water quality in Yangtze River estuary, in this paper, a DO-BOD-(NH3-N)-(PO3-4-P)-water quality mathematical model for the Yangtze River estuary-Hangzhou sea bay is built and used to simulate the sewage discharge process in Yangtze River estuary. The results show that the hydrodynamic condition is beneficial to sewage dilution and diffusion, for short-term excessive discharge（e.g 24h), pollutants can be diluted in short time; for long-term excessive discharge, the accumulation of pollutants will exert a worse impact for the estuary’s water quality, resulting in the deterioration of water quality.

Key words: excessive sewage discharge, water quality simulation；water environment impact, Yangtze River estuary