The Study On The Characteristics Of DASB And W-SFCW And The Sewage Treatment By DASB+W-SFCW Process

In order to quest for the adaptive processing for villages and small towns sewage treatment, this research raised a new treatment and reclamation project, that was Down-flow Anaerobic Suspended-media Bed (DASB)-Wavy Subsurface Constructed Wetland(W-SFCW) union system.Firstly, this thesis outlined the current status and developments of sewage treatment studies and applications world wide, it reviewed the anaerobic biology sewage treatment and constructed wetlands sewage treatment. The study raised the modified anaerobic reactor and constructed wetlands project. On that base, it established a new union process, which was appropriate for the villages and small towns sewage treatment.Secondly, the research individually focused on the characters of the core unit that was DASB and W-SFCWOn the design and research of anaerobic reactors, by using the septic tank outflow as wastewater source, the study run the small and medium experiments, which lasted one year and 10 months totally.Through the test, the research showed that in the environment temperature the was DASB a useful anaerobic reactor system, when HRT was 4 hours in the stable state, the removal efficiency of COD and BOD reached above 60% averagely.The thesis studied the parallel experiments between wavy-Subsurface Constructed Wetland (W-SFCW) and the traditional subsurface-flow constructed wetland( SFCW ).In this study, W-SFCW showed the better pollutions removal characters than SFCW, since its full removal capabilities in the vertical directions in the constructed wetlands. The main wastewater index such as COD, SS, NH/-N, TP ect. of the outflow in W-SFCW are all superior to the outflow of SFCW. In the same time, W-SFCW achieved the better capability of adaptation for different hydraulic load than SFCW.The study analyzed the evolution process of nitrogen and phosphorus in the constructed wetlands. The data showed that the content and distribution of nitrogen and phosphorus were agreed with the removal of nitrogen and phosphorus in the wastewater. In the same time, since the chemical process produced the indissoluble phosphates and the phosphates sedimentated the surface of the medium, the constructed wetlands would accomplish large capability of removing phosphorus.In the end, in a-year running process, the experiment concluded that the pollutions removal efficiency of DASB+W-SFCW was high than DASB+SFCW.