ABSTRACT
Initial rainwater treatment is an important concept of urban water environment management in China at present. According to the actual situation of a city in the south of China, this paper designed a wetland park for initial rainwater treatment. After preliminary treatment, the initial rainwater or polluted river water entered the horizontal subsurface flow constructed wetland and then was discharged into the natural water body after being treated again. Through the trial operation results, it can be seen that the wetland effluent meets the Class II standard of surface water, far exceeding the design requirements, and can be directly discharged into natural water bodies. After biochemical treatment, there is no significant difference between indexes of the initial rainwater and river water. After treatment, four indexes of wetland effluent have been significantly reduced, among which SS has the largest reduction rate, exceeding 90%, followed by NH3-N, TP and CODcr, with a minimum reduction rate of 33.3%, which indicates that the wetland has a very significant effect on sewage purification. The results show that the horizontal subsurface flow constructed wetland can be used to purify the initial rain and polluted river water, enhance the urban landscape, conform to the concept of “sponge city”, and is an effective measure of urban water environment control.
