| In recent years, efforts to control water pollution in China continued to increase, but the trend of deterioration of water pollution has not been fundamentally curbed. In the process of governance of the "three rivers and three lakes", non-point source pollution has aroused more and more attention. From the experience of pollution control in Dianchi Lake, Taihu Lake, Chaohu Basin shows that do not control nonpoint source pollution can not solve the water pollution problem fundamentally. To address the problem above, in this study, the Jiangnan Garden wetland catchment rainfall runoff for the object, by monitoring changes in rainfall and runoff water quality and quantity of the park, research on the effects of rain pond, miniature water features and a large slope road runoff filter control system on runoff water quality control and water cuts in Jiangnan garden wetland system. Through this study we found that:(1)Jiangnan Park accepted the rainfall runoff generated from the parking lot, pollutant concentrations showing a significant first increased and then decreased, The concentration of pollutants in runoff TN, TP, NH3-N, COD and TSS respectively in0.34~6.65mg/L?0.02~1.01mg/L?0.18~5.64mg/L?7.27~31.5mg/L?10~128mg/L, wherein the nitrogen exists mainly in the dissolved state, while phosphorus and COD is a larger proportion of particulate, at the same time as the cumulative rainfall in the early sunny increase in the number of days of rainfall runoff generated significantly increased concentration of pollutants.(2)For TN influent concentrations higher than 2mg / L of rainfall runoff, final effluent TN removal rate can reach 50% or more, at low concentrations of influent TN rainfall have a greater influence on the treatment effect. Because of the TP content generally low in rainfall runoff, while wetland system filler release P existence of the phenomenon, resulting in the overall treatment effect of phosphorus is low, the highest removal rate can reach 70.01%. Ammonia nitrogen removal performance of a high concentration removal efficiency is better than a low concentration, and by the early cumulative number of sunny days a greater impact, the maximum removal rate reached 66.04%,wetland system of nitrification and denitrification denitrification volatile and less correlated with rainfall, but significantly affected by the temperature, the flow of runoff during rainfall COD and TSS change by a large disturbance, the highest removal rate reached 68.3 % and 88.37%.(3)The rain pond maximum infiltration capacity of 0.262m/h, but as time increases, runoff carrying sediment deposited on the bottom of the pond, leading to infiltration volume decreased, the effect of rainfall infiltration on the pond is small, pond runoff control rate of up to 38.26%, with an inverse relationship between rainfall. Regulating role of miniature water features significantly, under normal circumstances it can adjust the volume of rainfall is 58.83m3, when rainfall is greater than 100mm(heavy rain), which can adjust the volume will increase to 184.4 m3. Filter system has a maximum capacity of infiltration 0.1223m/h, the minimum infiltration capacity of 0.096m/h, its runoff control rate with increasing runoff decreases, when rainfall is less than equal to 25.8mm, filter runoff system control rate of 100%, when the rainfall is greater than 26.5mm, the system can not completely filter runoff infiltration, runoff will flow into the part of the Longjing Lake directly embedded within the storm sewer. |
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