The Experiment Study Of A Novel Ecological Ditch Technique For Treatment Of Eutrophicated Water Body

With the rapid development of China's economy,a large number of inorganic and organic pollutants are produced and deteriorating our water environment.Aggravated water pollution and serious eutrophication of many water bodies threat to human health.Agricultural non-point source pollution is the main cause of eutrophication in China,leading to as high as 60%-80%eutrophication.Many researches on non-point source pollution have been carried out in a world wide scope,however,finding a cheap and effective technique to control eutrophication and elimate non-point source pollution is still of great significance.Ecological intercept technology,which is widely used in agricultural area,is an effective measure to control non-point source pollution and has been a hot spot of ecological science research.Ecological ditches make it more convenient and more adjustable to local conditions to cut down the runoff pollution.Therefore,supported by the National Science and Technology Major Project for the Control and Treatment of Water Pollution from the Ministry of Science and Technology of China under Grant No.?2012ZX07101-013?,the thesis developed a novel ecological ditch to treat eutrophicated water body.Lab-scale experiment was carried out to investigated the removal efficiency,and the optimal parameters of new packing materials.Based on the results,pilot-sacle ecological ditch was constructed in Changguangxi,Wuxi.The artificial ecological ditch system was constructed and two units were formed:1#and 2#as the parallel control,so as to make it more convenient to compare the results.Water was pump into the ecological ditch system,nutrients were removed from the water,then flowed into a secondary wetland for further purificed,finally return to the lake.Results indicated:?1?Scrap iron,scrap copper and woodchip were selected as the packing materials of the novel ecological ditch,the optimal ratio was10:1:0.5?weight?.?2?TP,DTP,TN,DTN,COD and NH₃-N concentration in inflow and outflow of the novel ecological ditch system were monitored,the system showed a resonable and stable effect on the removal of pollutants,especially on removing nitrogen and phosphorus.The removal rate?eached up to58.46%and 58.46%respectively and that of DTP,DTN,COD and NH₃-N were84.86%,57.50%,22.42%and 84.86%respectively,but the effect on NH₃-N and COD fluctuated widely.?3?Related data analysis showed that the ecological ditch removed phosphorus in water in two main ways:catalyzed iron internal electrolysis and water interception of the packing materials.The removal of nitrogen relied mainly on nitrification and denitrification process;?4?The change of weather conditions and hydraulic retention time had certain influence on the removal effects of ecological ditches.The optimal hydraulic retention time was 1 hour what's more,heavy rains had a significant correlation with the fluctuations of removal effect;?5?Considering experimental results,the cost of materials and other advantages,the reduction functions of the new-type ecological ditch technique on non-point source pollution are of high availability and therefore it has a wide application prospect.