A PHYSICOECOLOGICAL ENGINEERING EXPERIMENT FOR WATER-TREATMENT IN A HYPERTROPHIC LAKE IN CHINA

Covered by submerged plants, many shallow lakes in China had good wate r quality in the past and were sources of tap water. But now they are faced with eutrophication problems. For purifying raw water for tap wa ter 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 ma terials and filters. Water was pumped from one end of the PEEN to simu late the dynamics of different retention times. Six main principles fo r design and management were introduced in practice and dealt with in the paper. Some species of floating, leave-floating, and submerged pla nts, as well as attached algae, and malacozoan were inventoried and so me physical and integrated measurements of management were tested. Wat er quality indices of turbidity, ammonia-nitrogen, nitrite, and color were especially improved during the study. (C) 1998 Elsevier Science B .V. All rights reserved.