Eutrophication has become a serious environmental problem worldwide which has caused a serious of threats to aquatic ecosystems. Phosphorus (P) is the most important limiting nutrient in aquatic ecosystems, and excessive P negatively influences the ecosystem and causes eutrophication.  

Sediments play an essential role in the overall P dynamics of lakes. It acts as a sink to absorb P and a source to release P depending on concentration gradients. The exogenous P inputs will be gradually controlled by reducing pollutant discharge and enhancing the ecological remediation. Reducing internal P loads from sediment for eutrophication control has received great attention in ecology recovery. 

West Lake located on the western side of Hangzhou City, China, listed in the World Heritage Site in 2011. The research group led by Prof. Wu Zhenbin from Institute of Hydrobiology under the Chinese Academy of Sciences, recently investigate the high-efficiency clay as the eco-friendly capping material to control the internal P loading. The research group further developed the combined technology of modified clay material and submerged macrophyte to treat sediment P. 

The results revealed that the combined technology could effectively treat the sediment P in all fractions. Further study demonstrated that the combination of modified clay materials and submerged macrophyte exhibited a synergistic removal effect obviously higher than the summation of modified clay materials and submerged macrophyte applied separately. The eco-friendly combined technology has been applied to the ecological restoration demonstration project in West Lake, Hangzhou, brings great benefits in society and environment.  

This work has made certain contributions to the water environment protection and landscaping of West Lake for the 11^th G20 summit held in Hangzhou, China in September 2016. 

Related papers have been published in Science of the Total Environment, Environmental Pollution, and Scientific Reports.  

 
Sediment restoration demonstration area in West Lake. (Image by IHB)