Research On The Plant Roots And Hydraulic Load In Shallow Surface Flow Constructed Wetland

At present, there are less researches on hydraulics of artificial wetland system in China, while hydraulics of artificial wetland system can improve the effect of sewage purification significantly. By contrast to the skilled countries which have advanced technology about artificial wetland system, the wetlands constructed by our country currently are based on the traditional models and practical project experience. Only several artificial wetland systems consider the hydraulics-related issues in operation and construction, but they haven’t get the regular conclusion.This paper is based on the research of pollution control in shallow surface flow constructed wetland, which uses the sand as the matrix and myriophyllum aquaticum as the plant to consist of the shallow flow constructed wetland. The test is divided to three stages, the frist is preparation period, next is domestication period and followed by the maturity period. The main purpose of the preparation period is to set the experimental program to determine the drugs and procedures. The domestication period is to make the cultivated plants adapt to the system, so that to make sure the ability of pollutants control stabilized in further study of the system. The mature period means the test goes into the further research.The experiment shows that the COD> NH3-N and TP in effluent of shallow surface flow constructed wetland keep stably need about24days. Through the research on relationship between the different hydraulic conditions and the effect of pollutants control in system, the best hydraulic loading in system’s operation is100mm/d. The distance of system bed body has a certain influence on the effect of pollutants control related to the different hydraulic loadings, it shows that among the1/2bed body NH3-N can be removed85%of total removal rate, among3/4bed body COD and TP can be removed about90%of total removal rate. The experiment also analyze the change of pH and DO in shallow surface flow constructed wetland related to the different hydraulic loadings, it shows the pH in effluent stays stabilized in general as the hydraulic loadings changed, while the DO is related with the different hydraulic loadings, when the effect of pollutants control is obvious and stays higher, the levels of DO in effluent reduced to a minimum.Through the experimental simulation of shallow surface flow constructed wetland model, this paper analyse the pollutants removal rate of the system in different hydraulic loadings and obtain the first-order kinetic equation about the pollutants removal. I hope this paper can provide certain reference value in actual application.