STUDY ON TAIL WATER PURIFICATION BY COMBINED CHEMICAL AND ECOLOGICAL WETLANDS FROM MUNICIPAL SEWAGE TREATMENT PLANT

This paper took Jiangyin City Xinqiao Town sewage treatment plant as example to construct chemioal-ecological combined constructed wetlands system near natural river course to treat tail water from sewage treatment plant and investigated the removal efficiency of COD，ammonia，TN and TP in tail water． The research indicated that bio-ecological combined constructed wetlands system had good removal efficiency of pollutants in tail water． And the average removal rate of COD， ammonia，TN and TP were 29%，31%，18% and 8%，respectively; the average effluent concentrations of them were 35. 54， 0. 97，10. 77，0. 11 mg /L． The result exactly matched the first grade A standard of“Urban Sewage Treatment Plant Pollutant Discharge Standard”( GB 18918—2002) ． The technology had great potential for tail water treatment and was suitable for rural regions． The research result provided both the data and theoretical basis for improvement of biological treatment technology for tail water from sewage treatment plant，and also directed theoretical basis and practical experience for promotion and research of wetlands ecosystem．