Construction and Application of Constructed Wetlands

This paper presents the mechanisms and advantages of the constructed wetlands and indicates the research situation of the wetland construction and disposition of sewage by the constructed wetlands. It shows that many factors such as the components and levels of pollutants, the types of constructed wetlands, the categories of its plants and fillers, the hydraulic retention time as well as the load of hydropower can influence the efficiency of the constructed wetland. In China, there are three major types of constructed wetlands: vertical flow constructed wetland, subsurface flow constructed wetland and surface flow constructed wetland. These constructed wetlands are mainly used for treating the sewage from cesspit, nursery, paper mill, oil and coal mine, eutrophic lake and city life. During the construction course of wetlands, reed, cattail, herb of distinct pondweed and ladder brake are chosen as the dominating plants, and the phosphate, zeolite, sand, soil and coal cinder are chosen as the main fillers. According to research proceeding and application examples of the constructed wetlands used on disposition of sewage, the present paper has discussed the foreground of the constructed wetlands for wastewater treatment and investigations in the future. The author suggests that further research work on the basic theory and the popularization and application of constructed wetlands should be enhanced.