Aeration Of Urban River Pollution Of Nitrogen Form The Influence Of Migration

Nitrogen pollution was one of the outstanding problems need to be resolved in many polluted urban rivers Aeration technology because of its low investment cost, quick, widely used in the governance of the domestic and international urban polluted river. It was still uncommon system study of aeration to migration and transformation of urban polluted river water nitrogen.Water and sediment samples were collected from a heavily polluted urban river.Analysis of different aeration ways (aerating to sediments, aerating to water) on the overlying water, interstitial water and sediment of NH4+-N, N03--N and nitrogen forms such as the impact of the change process, using the indoor experiment method. Calculation of the diffusion flux of NH4+-N, NO3-N, NO2-N on sediment-water interface, analyzing the impact of aeration on the nitrogen migration of the sediment-water interface; the determination of DO, pH of the overlying water and the main physical and chemical nature of sediment, analysis of the efftct on the transformation and migration of nitrogen, initially reveal the effect of aeration on the nitrogen form of urban polluted river migration and transformation, in order to provide for the restoration of urban river water can learn from the information. The main conclusions of this paper were as follows:(1) Aeration can improve the dissolved oxygen of polluted river to promote the conversion of the overlying water column NH4+-N to nitrate, thereby reducing the concentration of NH4+-N, the removal rate of NH4+-N in aerating to sediments group and aerating to water group above95%; there was a significant difference (p<0.05) between aerating to sediments group and aerating to water group on the overlying water of NHU+-N concentration.(2) Under the combined effect of pH and DO in the aeration conditions on the nitrification process, mainly in the nitrification start-up time, aeration to sediments group lags behind aeration to water group; under aeration conditions, the sustain time of NO2-N accumulating was17days in aerating to water group and that was14days in aerating to sediments group.(3) Aerating to sediments was more effective for nitrogen removal than aerating to water, which was removed from pore water and sediment.At the experimental endpoint, the concentrations of NH4+-N in pore water and sediment were significantly decreased by63.39%and43.33%respectively compared with those before in aerating to sediments group and that were decreased by7.54%and13.98%respectively in aerating to water group; the concentrations of DTN in pore water decreased by74.09%in aerating to sediments group, significantly greater than43.24%of the group of aerating to water.(4) The variation of the diffusion flux of NH4+-N was similar between the control group and the aerating to water group across the sediment-water interface, there was a significant difference (p<0.05).between aerating to sediments group and aerating to water group on the the diffusion flux of NH4+-N, with the value of the aerating to sediments group lower than that of the other two groups; all operating conditions the diffusion flux of nitrate across sediment-water interface was negative, may be subject to the effect of interface redox conditions and the role of hydrodynamic.