Experimental Study On The Slightly Polluted Landscape River Using BAF With Pre-denitrification Process

In recent years, artificial lakes and scenic rivers continue to emerge in the construction of the park building and residential area. The water mostly is static or slowly closed water body with poor liquidity, generally easy to be polluted, and even be eutrophicated. Date shows that the COD, TN, TP and other indicators are over the surface water IV water quality standard in more than90%of China’s Park water. Many scenic water in the parks and residential districts of Shanghai, Beijing, Wuhan and other cities is subject to different degrees of pollution, Eutrophication increasingly intensified. The water quality of most scenic water of Beijing City Park is Grade V or even worse, then eutrophication will happen at different levels in summer, cyanobacterias float in part of the parks such as the Summer Palace, Taoranting Park, Beihai Park and other scenic water, and it seriously affects the water landscape. Water aeration is used to deal with the scenic water, but energy consumption is too high; because of higher infrastructure costs and pharmacy costs, chemical precipitation is also rarely used; Biological Aerated Filter (BAF) has a good effect in removal of pollutants, so it has been applied in sewage treatment and source water treatment at home and abroad. The purpose of this paper is to study the effect and influencing factors of biological aerated filter treatment in slightly polluted river landscape, discuss the better working conditions and pollutant removal mechanism of BAF treatment in slightly polluted river landscape for the characteristics of river landscape.Mainly the following conclusions(1) BAF has a stable removal for the organic, nitrogen and phosphorus in micro-pollution river landscape. The average removal rates of COD, total nitrogen, ammonia nitrogen, total phosphorus were83.7%,72%,92%and61%.(2) The better working conditions of BAF during the test treatment of slightly polluted river landscape:water load is0.64m3/m2.h, the volume ratio of Non-aeration and aeration zone is1:1,the ratio of air to water is5:1, Reflux ratio is300%. (3) In this experiment, the aeration heads are respectively in the0.1m and1.0m. But, the nitrogen removal between them is quite different. The reason, when the aeration head is in1.0m, is that The denitrification zone has been setted before the reactor, and then the denitrification process has been increased. However, the removal of ammonia nitrogen between the two is approximate, so it is favorable to the removal of TN.