The Removal Efficiencies On Seriously Polluted River Water In Free Water Surface Constructed Wetlands With Different Substrate

With the development of social economy, A lot of pollutions put into urban river,and make pollution becoming more and more seriously in our country, the rivermanagement is urgently. constructed wetland with small investment, good removalefficiency and low cost becoming effective way to control river pollution. At present,The tracking study on treatment highly pollution river is less in removal performanceand influence factors with different substrate surface flow constructed wetland. Studyon polluting the river water purification effect of river water environmental restorationand reconstruction has important practical significance.This research use river sand, coal as substrates in two free water surfaceconstructed wetlands (FWSCWs) with reed to investigate the performance and removalrules of highly polluted river water. The research include:(1) The purificationefficiencies of pollutants with free water surface constructed wetlands;(2)The changesof pollutants concentrations along the wetland beds of FWSCWs with differentsubstrates;(3) Analyzing removal efficiency of contaminants change with thetemperature, the water load, DO concentration in inflow water.;(4) Establish first orderkinetics model of the water pollutant removal, provides reference for the design of theFWSCWs.Study results are as follows:(1)When the hydraulic loading was0.1m/d, theaverage removal rates for COD，BOD，TN，NH4+-N，NO3--N，TP，PO4—P and SS were77.24%，90.16%，44.99%，41.20%，11.58%，51.12%，12.57%and91.80%in the sand CW,77.23%，89.59%，36.19%，25.35%，23.97%，45.79%，8.92%and90.11%in thecoal CW. There was no significant difference in removal efficiencies of COD, BOD andSS between the two systems, the removal efficiency of sand CW for TN, NH4+-N andTP was significantly higher than the coal CW.(2)Along both the wetland beds, the concentration of COD, BOD, TN，NH4+-N，NO3--N，TP，PO4—P were declined slowly and the speeds were decreased gradually, butthe concentration of SS was declined90%in the first quarter.(3)Temperature changes for removal rate on the COD, BOD, NO3–N、TP and PO4–Phas less impact. but has larger impact on TN、NH4+-N and SS. The efficiencies ofpollutants has different on river sand and coal WC wetland are affected by temperature,As the influent loading increased, the coal CW has more excellent ability to resist thanthe sand CW. River sand and coal CW cleaning the polluting river is mainly reflected bynitrogen and phosphorus removal efficiency. Control water pollutants concentration andtemperature, when DO concentration in inflow water. change between0.1~0.8mg/L,has less impact on pollutants removal efficiency.(4) Studying the surface flow constructed wetland hydraulic loading and thedynamics of the pollutant removal, level of correlation coefficient of the basic dynamicmodel at around0.9, shows that, under the certain condition of climate and inflowwater quality, using the first order kinetics model can better simulate the surface flowconstructed wetland on the degradation rules of pollutants...