Phoenix River Ecological Dynamic Model Research Of Artificial Wetland Nitrogen Removal

In recent years a large number of nitrogen, phosphorus and other material cause eutrophication of water bodies, a widespread social concern is caused.Constructed wetland as a land treatment system gradually mature, it’s on purpose of decontamination and also can add a green ecological park for the city. It both has economic and environmental value. Related research shows that the artificial wetland has good removal effect to nitrogen and phosphorus pollutants. While for the research time is short, understanding of the influence factor of artificial wetland nitrogen is not comprehensive enough, the design of both in and out water are all based on the experience, and corresponding dynamics research is not much.Take the phoenix river second ditch constructed wetland system as the research object, through field investigation and sampling analysis and so on, research the removal efficiency of pollutants (organic matter and nitrogen) of phoenix river wetland system. On the basis of the definition of reaction process, use the Stella simulation software to establish the ecological dynamics model of nitrogen removal, and forecast the effluent water quality.Conclusions are as follows:1, the monitoring data show that the artificial wetland effluent CODcr average concentration is 22.55 mg/l;TN average effluent concentration is 11.38 mg/l;Ammonia water average concentration of 1.65 mg/1, the water quality can meet the national discharge standard.2, through the winter and summer sampling monitoring data and comparison, the wetland in the summer of organic matter, TN, ammonia nitrogen removal efficiency is better than winter, artificial wetland in the summer (63.08%) of TN removal rate is higher than in winter (48.52%). When the environment temperature above 20℃, the wetland of TN removal rate has the obvious promotion, and obviously decreased when the temperature below 15℃.In addition the study found that when the phoenix river wetland water TN concentration of 32.54 mg/1, the maximum removal rate of 72.3%.3, by comparing the different types of wetlands, found that the free surface flow constructed wetland nitrogen removal rate is higher than the horizontal undercurrent type; And compare the two free surface flow constructed wetland, found that planting crassipes wetland removal effect is better than planting water celery, and planted canna, bulrush horizontal undercurrent artificial wetland of TN purification is better than plant a windmill grass.4, based on dynamic equation and mass conservation equation to construct the nitrogen removal of ecological dynamics model can well predict the effluent water quality of wetland. The fitting of ammonia nitrogen and TN has good accuracy, the fitting error was 7.26%, 9.19%. But lower than the previous build the denitrification of ecological dynamic model prediction accuracy. Analysis the research object of this article for the actual project, the phoenix river second ditch wetlands, compared with the previous studies of laboratory model of wetland, the concentration of water, pollution load and the operation parameters on the variability of larger, combined with practical engineering of environmental complexity and unknown input source factors are common caused the model built based on a practical project in this paper fitting precision is volatile. Compared with traditional first order kinetics equation again, found that the ecological dynamic model of wetland water prediction is more accurate and reliable than first order kinetics equation, error is within the scope of the smaller fluctuations.