Constructed Wetland System's Application On The Treatment Of Township Wastewater

The constructed wetland system technology is one kind of new ecology sewage treatment technology which developed in the 1970s,and at present,this technology obtained universal attention and application in many countries.Comparing with the traditional chemical treatment for sewage,this kind of processing technology has the advantage of low cost,more effect,ecological function and ecological landscape.The constructed wetland system technology has attracted more and more attention and has been applied in some southem cities and countries,but the application and research of this technology were so rare in Guizhou province.Some domestic studies mainly focused on experimental level without practical applications,moreover the scale is small.The lack of project application and operational experience has limited the application of constructed wetland technology in Guizhou areaA new constructed wetland using crushed stone bed processing were introduced from the South China Environmental science Research institute and environment engineering research center of State Environmental Protection Agency,and applied to the sewage treatment project in Baiyun District of Guiyang for its application research. In this article,considering the design of constructed wetland technology,the selection, culturing and distribution of plants,we carried out a comprehensive evaluation of the constructed wetland after analyzing the detected date of the water quality and plant.1,All the plants that cultured at the constructed wetland were the ideal plants.Through nearly two year plant selective breeding and cultivation,we found that Canna indica,Acorus calamus Linn,Vetiveria zizanioides(Linn.) Nash, Grassleaf Sweetfalg Rhizome,Colocasia antiquorum Schott,Alternanthera philoxeroides,Juncus effuses,Oenanthe javanica(Blume) DC,Rumex acetosa Linn, Poa annua,Inula britannica L,Festuca arundinacea grow well and can endure certain drought and flooding,these plants were the most best plants for constructed wetland,while,Ipomoea aquatica,Herba Lythri Salicariae,Brassica rapa pekinensis,Polygonum aviculare L,Hemerocallis fulva(L.) L,polygonum hydropiper L also performed well at the constructed wetland,which indicates that all those plants can apply to constructed wetland.At the same time,through the community's construction of wetland plant,the effect of actual growth proved that Canna indica + Colocasia antiquorum Schott + Festuca arundinacea,Acorus calamus Linn + Grassleaf Sweetfalg Rhizome + Festuca arundinacea,Vetiveria zizanioides(Linn.) Nash + Canna indica,Canna indica + Juncus effuses have large amount of biomass and significant effect in purification,so this combinations could be applied and intensified in the Guiyang.2,The physics and chemistry index of water quality were obviously improvement.After the analysis of the index of water quality of the constructed wetland in Dula Township,the result showed that the total pollution of water were obviously decreased and the function of the water were significantly improved.In the three ranked constructed wetlands,the effect of plant's purification in the first level wetland were more obvious than other levels as the waste water firstly poured into the first level wetland.Overall,all the index of water quality has reached the desired goal as follows:COD_cr≤50mg/L;BOD₅≤10mg/L;SS≤10mg/L;TN≤5～8mg/L;TP≤0.5mg/L.3,The reasonable plant community arrangements could make the effect of landscape of wetland more prominent.With the great effort of our team,not only the landscape of naked gravel of the constructed wetland were obviously improved by reasonable plant community arrangements,but also the scenery of the microenvironment were significantly changed for the better with Canna indica,Acorus calamus Linn,Cyperusalternifolius, Colocasia antiquorum Schott,Helianthus annuus cultured in the wetland.The plants such as Humulus japonicus,Herba Lythri Salicariae,Cucurbita moschata cultured in the wetland played an important role in the landscape. 4,A certain economic efficiency has produced along with the implementation of the project of the constructed wetland.During the implementation of the project of the constructed wetland,not only a certain economic efficiency has produced by cultured Brassica rapa L.Chinensis Group, Brassica rapa pekinensis,Ipomoea aquatica,Oenanthe javanica(Blume) DC,Herba Coriandri Sativi in the wetland and Cucurbita moschata,Zea mays L along the pool wall,but also the landscape and water quality were significantly improved.