AN EXPERIMENTAL STUDY ON THE PHYSIO-ECOLOGICAL ENGINEERING FOR IMPROVING TAIHU LAKE WATER QUALITY IN WATER SOURCE AREA OF MASHAN DRINKING WATER PLANT

Abstract

以太湖无锡市马山水厂水源区的实验工程为例,论述了改善湖泊饮用水源水质的物理-生态工程的原理和效益。工程原则上能适用于不同的水深、水质、底泥和风浪条件。在两年实验中,工程技术和管理不断改进完善,经受住了多次大风浪考验。工程能有效地削减进入自来水厂水源的藻类,除藻率平均达59—78%以上。工程对TN、TP、NH₄⁺-N、BOD₅、COD_Mn浊度的降低率分别为24—45%、2—24%、5—70%、9—61%、10—25%和9—40%。采用特殊技术后风眼莲可在有大风浪的大水面生长,其夏季生产力507g/（m²·d）,净化水质和抑制藻类生长作用显著。可降低处理自来水的氯耗量,并使外湖藻害基本上不成为用水高峰时增加产水量的限制因素,从而以更好更多的自来水满足日益增长的用水需要。;The principles and benefits of the physic-ecological engineering (PEE) for improving drinking water quality in a lake are dealt with a sample experimental engineering in water source area of Mashan Drinking Water Plant of Wuxi City in Taihu Lake. The PEE may be used in principle for different conditions of depth, water quality.bottom sediment and wind wave.The PEE has its main objects of reducing algae concentration and improving the hydrochemical indecies of water quality in enclosed intake area of a water supply plant, including two parts of physical and ecological engineering. During the experiment of two years, the technology and management of the PEE have been much improved and experienced many time of storms and strong wind waves.The PEE may effectively reduce the algae concentration and improve the water quality. The mean rate of reducing algae concentration is more than 59-78%;the rates of reducing of turbidity and concentrations of TN,TP,NH₄⁺-N,BOD₅ and CODM_Mn are 9—40%,24—45%,2—24%,5—70%,9—61%,and 10—25% respectively. Using a special technology, the Eichhoma irassipes solms may maintain its growth under strong wave condition on the open lake surface,and its productivity in summer accounts 507 g/(m₂·d), which lead to purifying the water and restrain the algae growth. The PEE may reduce the chlorine expenditure and increase the drinking water output without the limitation caused by water bloom in lake.