Strategy & Techniques for Restoration of Healthy Aquaecosystem from Toxic Super Eutrophic Water Body

摘要

There are complex river-lake systems in theTaihu Lake catchment with total water surface area of 6174.7 km2, andpopulation density of 1079/km2, including Taihu Lake water surface area of 2338km2. The water systems in this catchment have healthy aquaecosystems duringlong history. However, in some riverlets in this catchment the water quality wasestimated as “acute toxicity for higher organisms” and over standards for manyheavy metal elements content; there were no any living plants and macroorganisms in the water body, because there were developed a series of industrywith abundant release of heavy metals and difficult decomposition organic chemicalcomponents along the riverlets during last decades. The even more serioussituation was observed in sediments of the riverlets. How to restore suchriverlet into a healthy aquaeosystem with abound plants and higher organisms?The main strategy and techniques are described in this paper as summarizing a reportof engineering in a riverlet in Wuxi New District during last years, whichleads to restore the aquaecosystem into a healthy one with abundant surfaceplant cultured on floating islands and observed living fish, lobster, frog,toad, mollusk and others in the riverlet. The main techniques are: 1) softwallbuffer technic; 2) floating eco-island technic by using which can culture anyplant which can be cultured in solution; 3) immobilized nitrogen cycle bacteria(INCB) technic; 4) tattering esters and other big-molecule organic chemicals byusing electronic pulse technic and photosensitization technic; 5) mist sprayfacility technic for improving dissolved oxygen in deep water layers; 6)technic for buffering and suppressing H2S release from water; 7) the appropriateportion of surface with cultured plant to the total water surface area is about1/3; 8) Cress [Oenanthe Ljavanica (Bl.) DC.] and Myriophyllum verticilatum L.may be cultured in Taihu Lake catchment during the whole year as main plantswith mosaic combination of other supplement plants in different seasons.