Environmental capacity of chemical oxygen demand in the Bohai Sea： modeling and calculation

• Published in: Chinese journal of oceanology and limnology Vol. 29; no. 1; pp. 46 - 52
• Main Authors: Zhao, Xixi, Wang, Xiulin, Shi, Xiaoyong, Li, Keqiang, Ding, Dongsheng
• Format: Journal Article
• Language: English
• Published: Heidelberg SP Science Press 2011; Springer Nature B.V
• Subjects: Bays; Chemical oxygen demand; Chemicals; Discharge; Earth and Environmental Science; Earth Sciences; Environment; Freshwater; Marine; Mathematical models; Oceanography; Oxygen; Oxygen requirement; Physics; Rivers; Seawater; Three dimensional models; Water pollution; 中国国家标准; 化学需氧量; 对流扩散模型; 污染物排放; 渤海湾; 环境容量; 计算能力; Bohai Sea; INW, China, People's Rep., Liaoning Prov., Liaodong Bay; INW, Bohai Sea, Bohai Bay; China, People's Rep., Huang He R; INW, China, People's Rep, Shandong Prov., Laizhou Bay; INW, Bohai Sea; chemical oxygen demand (COD); environmental capacity (EC); degradation process; Bohai Sea
• ISSN: 0254-4059; 2096-5508; 1993-5005; 2523-3521
• DOI: 10.1007/s00343-011-9080-3

A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand （COD）. Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity （EC） and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77× 10 4 t/a, 116× 10 4 t/a, 154× 10 4t/a and 193× 10 4 t/a, respectively. The Huanghe （Yellow） River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River （11.5%）, and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.