The 11th International Conference on Water Resource and Environment (WRE 2025)

Abstract: Erhai Lake, the second-largest freshwater lake on the Yunnan–Guizhou Plateau, covers an area of 252 km² with an average depth of 10.5 m, and its watershed is approximately ten times the size of the lake itself. In recent years, comprehensive management efforts have yielded remarkable improvements: the total nitrogen (TN) and total phosphorus (TP) loads from inflowing rivers have decreased by about 35% within six years, leading to a notable enhancement in overall water quality. However, the chemical oxygen demand (COD) and permanganate index have remained persistently high, emerging as critical factors preventing the lake from meeting water quality standards. Our study revealed pronounced shifts in the algal community structure of Erhai Lake, with dominant taxa alternating among Cyanophyta, Bacillariophyta, Chlorophyta, and Pyrrophyta. Cluster analysis indicated a strong correlation between algal dominance, biomass, and COD concentration. Fluorescence spectroscopy and nuclear magnetic resonance analyses further demonstrated that extracellular polymeric substances (EPS) produced during algal growth and metabolism directly contribute to elevated COD levels. Notably, approximately two-thirds of the EPS produced by pseudoanabaena sp. are resistant to rapid biodegradation. Future research should therefore focus on algal community succession and organic matter transformation processes to support the sustained improvement of Erhai Lake’s water quality and ecosystem stability.

Biography: Prof. Wang Xinze is a Chief Researcher in School of Environmental Science and Engineering, Shanghai Jiao Tong University (SJTU), China. Dr Wang obtained his Ph.D. in Environmental Engineering from Harbin Institute of Technology, China in 2002. Dr Wang is Director of the Erhai Lake National Field Scientific Observation and Research Station in Yunnan and Dean of Yunnan Dali Research institute of SJTU. Dr Wang’s research focuses on lake eutrophication control and rural area domestic wastewater treatment. Dr Wang has published more than 100 research articles on wastewater treatment or lake eutrophication control. Dr Wang has been granted over 20 patents, The patented technologies have been successfully applied in Dali, Yunnan. In addition, he serves as a council member of the Lake Branch under the Chinese Society of Oceanology and Limnology and on the editorial board of the Journal of Environmental Engineering Technology.