Natural Wetlands Utilization for Un-Collected Village Sewage Treatment

A pre-research was conducted to validate the availability of using nuatral wetland to control village sewage and improving water quallity in reservior. Removal of COD, TP, TN, NH₄-N, As, Cd and Hg by tested natural wetland both in growing period and decaying period was tested. Characteristics of soil and plant in tested wetland were also analyzed. The results showed that the maximum removal by tested wetland is about 40% of TP, 55% of TN, 9.5% of NH₄ ⁺-N and 30% of COD in May. In October, TP removal increased, while other parameters removal decreased. Pollutant contents in some of the sampling sites even increased, mainly caused by the high level pollutants from agricultural runoff and poultry plant aside. From this point, natural wetland for wastewater treatment at the studied sites seemed a little difficult and pretreatment of the high level pollutants is important.