自净作用下渤海海域COD环境容量研究

为测算自净作用下我国渤海COD环境容量,按地理特征将渤海水域划分为莱州湾、渤海湾、辽东湾以及渤海中部4个分区,从水动力交换扩散和化学降解两个方面入手,一方面利用各分区水半交换周期分别求得COD的扩散能力,另一方面利用COD衰减规律得到其降解能力,综合后得到各分区在不同水质标准下COD的环境容量.研究表明,渤海各湾水域COD浓度和环境容量各不相同,其中,莱州湾水质属于较清洁,在此区间内还有26%的环境余量;渤海湾水质属于轻度污染,在此区间内还有5%的环境余量,辽东湾水质属于较清洁,在此区间内还有88%的环境余量.

COD environmental capacity of different zones of the Bohai Sea with the consideration of self-purification

To determine the partial water quality, it is essential to divide large water area into smaller partitions according to the geographical structure. In present paper, China’s Bohai Sea was divided into four zones (i.e., Laizhou Bay, Bohai Bay, Liaodong Bay and the center of Bohai Sea). The hydrodynamic induced mass convection and diffusion and the chemical degradation were considered, the former was used to compute the diffusion capability of cumulative chemical oxygen demand (COD) in different zones, and the latter was applied to solve COD decreasing property, thus the degradation ability could be estimated. After the comprehensive consideration of these two parts, the COD environmental capacity was obtained with different water quality standards considered. The result shows that COD capacity is different in these four areas. For Laizhou Bay, the COD concentrations could satisfy the standard of “relatively clean”, and the environmental capacity has additional 26% to reach the standard; For Laizhou Bay, the COD concentrations was very close to the standard of “light pollution”, and the environmental capacity only has 5% left. For Liaodong Bay, COD concentrations met the standard of “relatively clean”, and the environmental capacity remained 88%.