|
In this study, Qingpu modern agriculture park as test base, from screening to intercept paddy efficient drainage of nitrogen and phosphorus aquatic plants start to build an eco-ditch - wetland drainage system, water from the process on the reduction of contaminants, especially nitrogen and phosphorus content, thus preventing the withdrawal of water scattered row of farmland caused by agricultural nonpoint source pollution and emissions due directly to the river caused by eutrophication. The main results are as follows: (1) The test found that aquatic pollution load on water purification effect is not obvious, if you want to make it work, required hydraulic retention time control in two days or less, therefore, when applied to ditches and wetlands ecological construction, follow-up investigations to fully drain water quality conditions, timely adjustment of operating parameters, especially hydraulic retention time. Pollution load on the soil itself purifying effect of water is also good, from an economic point of view, the use of traditional paddy soil drainage ditch as sufficient; But ecological point of view, should select the appropriate moisture, cold, heat plants planted in ditch on both sides, soil and water, improve the ecological environment. When paddy drainage in the high pollution load stage (fertilizers, pesticides, after a large number of application), soil purification capacity has been insufficient in itself sufficient to intercept nitrogen and phosphorus. At this time, large amounts of nitrogen and phosphorus will vary with paddy drainage into nearby rivers and lakes, causing eutrophication, the trench laid appropriate aquatic plants, can play a slow flow rate of paddy drainage, nitrogen and phosphorus removal, improve water dissolved oxygen, pH value of water stabilizing role. For example, the concentration of total phosphorus vetiver for pollution control has a strong effect; Iris on ammonia nitrogen pollution control has a strong role; cattails high removal of COD load has a strong role. From the test results, the removal of pollutants by aquatic plants HRT greater impact, therefore, can not be one-sided to say what good and bad plants, only in accordance with the contaminated water and the water quality of the means of governance HRT designed to select the appropriate aquatic species. (2) The trial on the ecological ditches in a project after the end of a five-day trial run, through a trial run, eco-ditch deal initially achieved its expected quality, HRT five days later, ditches on the main pollutants N, P, COD removal rate reached more than 30%, and some even reached 50% or more, look at the data from a trial run in the non-rainfall conditions, emergent plants floating plants laid in such manner that a combination of ecological ditch water pollution play a greater purification capacity. (3) This test also built a water purification, ecological restoration, cultural transmission and other functions in one of the artificial wetlands, reflecting a significant integrated functionality. In this study, paddy field drainage system built into aquatic Screening - ecological infrastructure ditches - ditches plant layout - build four wetlands areas, more successful screening of aquatic plants, ecological ditches test run more stable, eco- wetlands more robust functionality, the entire system is more smooth series, I believe that after 2011 the implementation of two projects, the construction of the drainage system paddy will be more perfect.
|