Treatment Of The Organic Matters Of The Polluted River Water In Constructed Wetland

Zaohe River as the main pollution source of the Weihe River, discharged70000tons COD into Weihe River per year, which accounted for50%of the COD of Xi’an.Measures should be adopted to treat the polluted water to improve the water quality ofZaohe River and lower the pollution load of Weihe River. Constructed wetland（cw）treatment system has good treatment effect of organic matter lower costs forconstruction and operation and simple maintenance, resulted in it has great advantagesin the urban river pollution treatment.Combined with the operation practice of Zaohe cw demonstration project, thispaper analysed the mechanism of organic wastewater treatment in cw, conducted aone-year operation condition analysis and monitored COD, BOD5and TOC of inflowand effluent of the various series of cw. The main content of this research:(1)Compared the treatment efficiencies of organic matter from heavily polluted riverbetween different types of cw;(2) Compared the treatment efficiencies of organicmatter from heavily polluted river between the combined cw and single cw, and thedifferent types of combined cws;(3)Studied different factors (plants, filler, seasons) onthe removal efficiency of organic matter from heavily polluted river;(4) Set up themodel of the removal of organic matter along the surface constructed wetland (FWS);(5) Analyzed the problem during the operation and management of the demonstrationproject and proposed the methods to perfection.The results of this research indicated:(1) high removal efficiencies of organicmatte can be achieved in deferent cw, the removal efficiency of COD and BOD5was70%~75%and88%~90%, respectively. The removal efficiency of organic matte inFWS was higher than in subsurface flowed constructed wetland (SFS);(2) The removal efficiency of organic matte in combined cw was higher than that in single cw,the removal efficiency of COD and BOD5was77%~82%and90%~97%, respectively.The combined processes of two SSFs and a FWS had the highest removal efficiency oforganic matte;(3)The filler plays an important role in the removal of organic matter atthe beginning of the cw running, slag, gravel and brick had different features in theremoval of organic matters, and the difference weakened along the time.(4) The plantplays an important role in the removal of organic matte in cw, but the different betweenthe plants was not significant, the concentration of COD in the outflow was minimal inthe autumn.