A physico-ecological engineering experiment for water treatment in a hypertrophic lake in China

Covered by submerged plants, many shallow lakes in China had good water quality in the past and were sources of tap water. But now they are faced with eutrophication problems. For purifying raw water for tap water treatment, a physico-ecological engineering (PEEN) experiment has been carried out in a hypertrophic bay of Taihu Lake, China since June 1994. Ten channels with widths of 5 m and lengths of 40 m (total area of 2000 m 2) were constructed using bamboo stakes, water-isolated materials and filters. Water was pumped from one end of the PEEN to simulate the dynamics of different retention times. Six main principles for design and management were introduced in practice and dealt with in the paper. Some species of floating, leave-floating, and submerged plants, as well as attached algae, and malacozoan were inventoried and some physical and integrated measurements of management were tested. Water quality indices of turbidity, ammonia-nitrogen, nitrite, and color were especially improved during the study.