钦州湾三墩作业区排污阈值的数值模拟研究

Numerical Simulation on Emission Threshold of Sandun Operation Area in Qinzhou Bay of China

关键词:  钦州湾  三墩作业区  数值模型(EFDC)  排污阈值  污染物

Key words:  Qinzhou Bay  Sandun operation area  numerical simulation (EFDC)  pollution discharge threshold  pollutant

摘要:

排污容量的研究对海洋生态环境保护有重要意义。随着钦州湾茅尾海污染呈逐渐严重趋势，为改善水质状况，钦州市将排污口外迁至三墩作业区，因此，研究该区域的排污阈值可为决策提供科学依据。本研究通过一阶降解系数的物质对流-扩散模型模拟钦州湾三墩区不同排污口的扩散情景，选出最优排污口并计算排污阈值。研究表明：不同排污口排放的物质扩散方向基本为SW-NE向，同时西南端排污口的污染物扩散范围小于东北端排污口的污染物扩散范围，因此三墩作业区的最优排污口位置位于西南端（21.601 101°N，108.670 364°E）；COD_Cr、TN和TP分别执行≤60 mg/L、≤40 mg/L和≤0.5 mg/L标准时，相应的排污阈值依次为76 845.25，1 581.7和150.2 t/a。

Abstract:

The study of pollution discharge capacity is of great significance to the protection of marine ecological environment.As the pollution of Maowei Sea in Qinzhou Bay is becoming more and more serious,in order to improve the water quality,the sewage outlet has been moved outside to Sandun operation area by Qinzhou government.Therefore,the study of the sewage threshold in this area can provide scientific basis for decision making.In this study,a first-order degradation coefficient material convection diffusion model is used to simulate the diffusion scenarios of different sewage outlets in Sandun District of Qinzhou Bay,and the optimal sewage outlet is selected and the sewage threshold is calculated.The research shows that the material diffusion direction of different sewage outlets is basically SW-NE,and the pollutant diffusion range of the southwest sewage outlet is smaller than that of the northeast sewage outlet.Therefore,the optimal sewage outlet position of Sandun operation area is located in the southwest end (21.601 101°N,108.670 364°E).When the standards of COD_Cr,TN and TP are ≤ 60 mg/L, ≤ 40 mg/L and ≤ 0.5 mg/L,the corresponding pollution discharge thresholds are 76 845.25,1 581.7 and 150.2 t/a,respectively.