Study On The Effect And Mechanism Of Removing Heavy Metals Of Sewage Of SFCW Planting Canna

In recent years, serious pollution of rural water environment in our country obstructed the development of rural social economics, in addition to the pollution of organic matter, nitrogen and phosphorus, heavy metal pollution is widespread existence in rural water environment. Heavy metal pollution of rural water environment not only threatened health of citizens but also made heavy metal contents of the lager part of agricultural products exceed the criterion to be limit to export. So it is necessary to develope the control research of heavy metal pollution of rural water environment.CW (Constructed Wetland) is a natural ecosystem of sewage treatment technology, its main principle of sewage treatment is to make use of the action between soil, plant and microorganism and a series of the paths of physics, chemistry and living creature, is applicable to control rural superficial water pollution. In the last ten years, domestic and foreign researchers carried on a great deal of research to it, the research mostly focused on structure of system, effect and mechanism of decontamination, applied realm etc., in which a lot were on the organic matter, nitrogen, phosphoric of sewage and few was on the heavy metals.The researchers from Yangzhou University suggested the study on DATB (Down-flow Anaerobic Turbulent Bed) & W-SFCW (Wavy Subsurface Flow Constructed Wetland) technology treatment of rural domestic sewage, obtained a better research result, but could not make further study on effect of wiping off heavy metals.Based on foregoing research, the thesis would made a chiefly study on effect and mechanism of wiping off heavy metals of SFCW.The results of monitoring for a year indicated that when the concentrations of influent were: Cu=5.28 mg/L, Zn=6.38 mg/L, Pb=3.02 mg/L, Cd=3.52 mg/L, the correspondent removal rates were: 70.69 %, 66.71 %, 74.66 %, 61.87 %; that by analysing the contents of Cu, Zn, Pb, Cd in each layer of soil and each part of plant of SFCW, the results made clear that the primary mechanism was adsorption of soil and absorption of plant and heavy metals mostly deposited in soil and plant; and that research results elicited that heavy metal exerted...