ABSTRACT
Water hyacinth has a strong capacity to absorb nutrients, heavy metals and organic pollutants and is an excellent candidate for the water pollution control and eutrophic water restoration. In large lakes, there were few successful examples of submerged or emerging macrophyte restoration. In aquatic environments, total nitrogen, ammonium and nitrate nitrogen are closely related because mineralization of organic matter (including decomposition of blue-green algae) increases ammonium concentration, which is easily converted to nitrate in aerobic conditions such as during the testing period. This chapter presents the results on water quality and ecological risk assessment in two ecological engineering projects on phytoremediation of eutrophic lakes: Lake Dianchi and Lake Taihu in China. In 2012, the use of water hyacinth for phytoremediation of eutrophic water was extended at the northern part of Wai Hai and the whole of Cao Hai in Lake Dianchi.
