北京什刹海生态修复试验工程

Approaches to the Ecological Recovery Engineering in Lake Shishahai,Beijing

什刹海是北京市一个小型浅水城市风景游览的富营养湖泊.生态恢复试验工程以物理除藻为前提,通过实施基底修复而后开展水体充氧等手段,达到恢复水生植被的根本目的.应用的修复技术有:(1)臭氧/超声波除藻;(2)基底修复;(3)水下曝气充氧及冬季冰下底部充氧;(4)上游区复合生物浮床;(5)水下光补偿技术;(6)高等水生植物栽植与优化配置;(7)水生植物调控与机械割草;(8)水质净化与保洁管理.工程实施近1年(2001年8月-2002年6月)后效果明显,总氮、总磷分别下降了4.74mg/L和0.45mg/L,去除率达到79%和91%,什刹海的水质也由Ⅴ类上升为Ⅳ类.

Shishahai Lake is a scenic and sightseeing lake in central Beijing.Before the ecologic re-covery testing,it was under heavy eutrophication.Indexes of BOD 5, NH 3 -N,Permanganate Index and TP were over V-Class of Chinese Environmental Quality Standards For Surface Water with dominant alga of bellamya microcystis.Several technologies were used in the e-cological recovery for Lake Shishahai,i.e.,ozone/supersonic algae removal,aeration,floating bio-bed technology,lake bottom recovery,hydrophyte planting and recovering and biological adjustment and control.After more than ten months'testing of ecological recovery,the eco-logical environment has improved obviously.TN and TP content are1.26mg/L and0.046mg/L,which were reduced79%and91%separately for TN and TP.Meanwhile,the chloro-phyll.a content was decreased with notable deeper transparency in the lake.The general e-valuation of water quality is IV Class.