Modelling Dissolved Oxygen Depression in an Urban River in China

Water

Jingshui Huang¹  Hailong Yin¹  Qi Zhou¹  Steven C. Chapra² 

[1] College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China;Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155, USA;

关键词: dissolved oxygen;    eutrophication;    black and odorous water body;    WASP model;    water quality management;   

DOI  :  10.3390/w9070520

来源: DOAJ

【 摘 要 】

Dissolved oxygen (DO) depression in urban rivers appears to be increasing in developing countries, which causes severe aquatic ecosystem stresses. One urban river which suffers DO depression under low flow conditions and requires systematic research for effective mitigation strategies is the Nanfei River (Hefei, China). We investigated its longitudinal profiles of DO and other related water constituents with high spatial resolution monitoring at low flow. A mechanistic DO model for the reach was customized and calibrated with the data obtained. We found that the daily average DO levels within the 11 km study reach shifted from supersaturation (11.5 mg L−1) upstream of the Wangtang Wastewater Treatment Plant (WWTP) to serious depletion (3.6 mg L−1) downstream. Process analysis indicated that DO production via strong algal photosynthesis overwhelmed the DO consumptions upstream from the WWTP. In contrast, DO sources could not compensate for DO consumptions, wherein carbonaceous deoxygenation was the largest consumer of the DO (approximately 70%) downstream the WWTP. Rather than directly contributing labile organics, the WWTP effluent affected the DO balance by shifting the metabolism from upstream autotrophy to downstream heterotrophy. Finally, mitigation strategies for DO depression in rivers in rapidly-urbanizing regions were suggested accordingly.

【 授权许可】

Unknown