汕头港海域氮、磷营养盐环境容量及排放总量控制的研究

The nitrogen and phosphorus environmental capacity and total pollutant amount control in coastal Shantou Port

采用带有干湿网格技术的POM08模型,对汕头港海域的二维垂向平均潮流场进行了数值模拟;同时耦合二维物质输运方程,采用分担率法计算了该海域6个入海污染源的氮、磷营养盐环境容量,并在此基础上进行了减排方案设计模拟。结果表明:水动力模拟结果与实测数据吻合较好;在对汕头港6个污染源的氮、磷营养盐的总量控制中,应重点关注榕江、外沙河、梅溪和新津河各污染物的入海通量;整个汕头港海域氮污染较严重,现有监测质量已不满足规定的水质保护目标,需采取严格的削减措施;整个汕头港海域磷污染相对较轻,采取一定的减排措施可以达到规定的水质保护目标;对于无机氮,榕江至少要减排95%,外沙河减排65%,其余污染源减排90%或适当降低减排率,才能使整个汕头港海域无机氮浓度基本满足相应的水质保护目标;对于活性磷酸盐,榕江至少要减排5%,梅溪、外沙河减排25%,其余污染源减排5%,才能使整个汕头港海域活性磷酸盐浓度基本满足相应的水质保护目标。

A POM08 model with a wetting and drying scheme was applied to simulate the two-dimensional and ver- tical-averaged tide and tidal current in the coast in Shantou Port, Guangdong Province. A two-dimensional materi- al transport equation was coupled with the model to calculate the nitrogen and phosphorus environmental capacity of six pollution sources in the coast with sharing rate method, on which a simulation of reduction plan design was con- ducted. The computed hydrodynamic results showed agreement well with the observed ones. The environmental ca- pacity results showed that more attention should be paid to the pollutant fluxes from Rongjiang River, Waishahe, Meixi River and Xinjin River in the nitrogen and phosphorus control. A strict reduction plan should be executed for the serious pollution of nitrogen. However, a certain abatement measure may work since the phosphorus pollution is lighter. The reduction plan design results showed that a reduction percent of 95 for Rongjiang River, 65 for Waisha- he and 90 or less for other pollution sources could make the water quality meet the corresponding protection stand- ards for the inorganic nitrogen; a reduction percent of 5 for Rongjiang River, 25 for Meixi River and Waishahe, 5 for other pollution sources could make the water quality meet the corresponding protection standards for the active phosphorus.