Applied Study Of The Submerged Macrophytes-Immobilized Bacteria In Drinking Water Restoration

Eutrophication has negative influence on quality of drinking water,73.9% water quality of taihu was bad than level V, the main Indicator which exceed water quality level was TN and TP, gonghu was Mild eutrophication in 2009, deterioration Of water quality lead to decrease of aquatic plant and affected water safety.One of the main reasons which resulted in deterioration Of water quality is nitrogen concentration, so, the technology for reducing nitrogen concentration has important significance.The experiment area have characteristics of Strong storm, fast lakecurrent, Significant correlations between water quality and weather, no sediment, we found the Suitable Submerged macrophytes for water restoration, isolated ammonifying bacteria,nitrobacteria,nitrosobacteria and denitrifying bacteria from taihu, studied the Submerged macrophytes and bacteria's water purification effect, researched denitrification mechanism with isotope pairing technique, tested the new technology in river and drinking water, obtained the Submerged macrophytes-bed technology, which had good ability to resist storm and good effects on water purification, the experiment results could be theoretical Basis and technical Support of water restoration, The main conclusions are as follows:(1) In terms of water purification,the effect of Submerged macrophytes-Immobilized bacteria was better than Immobilized bacteria only,and Immobilized bacteria was better than macrophytes. Immobilized bacteria play a leading role in water purification. (2) Both of macrophytes and Immobilized bacteria could promote the denitrification and reduced Water pollutant of nitrogen,as macrophytes had more influence on DN and Immobilized bacteria had more influence on DW(3) Submerged macrophytes could increase dissolved oxygen, reduce percent conversion of N2O to N2,so the N2O flux was higher than other groups when Submerged macrophytes exist(4) The technology of Submerged macrophytes bed-Immobilized bacteria had good ability to resist storm, it could increase the denitrifying bacteria number observably and promote denitrification,this technology had stable effect for water purification. The denitrifying bacteria number increased from 5.4×102～2.7×103 to 3.9×105～9.1×105 during the experiment, N2O flux of experimental plot was 3～24μg·(m2·h)-1,it's more than the contrast group obviously, TN concentration reduced 19-74%,while NO3- concentration reduced 24-81% after the equipment running a period of time; The experimental data of 120 days showed that this technology is suitable for drinking water restoration,as it can controle eutrophication.