Study On Treatment Of Biological Contact Oxidization And Greenhouse Structure Subsurface-Flow Constructed Wetland For Processing Rural Domestic Sewage

With the development of economic and the growth of population in China, the demand for water increases, while the emission of non-doxycycline domestic sewage has formed much more pressure for water environment. Compared to traditional technology, constructed wetland technology needs low operating costs, low investments, low level of regulatory requirements, and can remove nitrogen and phosphorus , high treat efficiency, it is suitable for domestic sewage of small towns. But limited by cold climate, the application of constructed wetlands has much trouble in in Northern China.Against the problem of frozen in winter, the "biological contact oxidation and greenhouse structure subsurface constructed wetland system" was used to dealing with Hailin farm sewage, and effect of the project during the operation was investigated in order to find a way to widen the application area in Northern China.During the test, the removal of COD, NH₄⁺-N and TP was focused. The results show that the ability of combined process in pollution removal of sewage in winter was stable. In the whole process, the concentration of COD, NH₄⁺-N and TP in the outflow was about 23.76, 6.26 and 1.85 mg/L respectively. The combination process can overcome the disadvantage of the single subsurface wetland and improve the pollution removal efficiency in winter.Isolated by the sunlight board, the operation of subsurface flow constructed wetland was normal in winter, greenhouse and other insulation measures effectively ensure the smooth flow of the pipeline to maintain a higher temperature (8℃above). COD removal by the combined process of low temperature in winter has little, and the effect on COD removal rate remained at 80%, the outflow water reached the first level A, but the removal efficiency of wetlands on N, P was decreased. In addition, two-stage subsurface flow constructed wetland in series, through the concentration of pollutants along the way to detect the profile and found that COD, N, P removal was mainly done in front of wetlands, the removal of pollutants was to push the basic flow state .The cost for water treatment in every ton is about 0.6 yuan, the treated sewage can be used for irrigation, and recycle water reaches 146000 m³, which can ease the local water shortage in a certain degree. In addition, the aging sludge and wetland plants can be recycled, produced by anaerobic digestion biogas for power generation, the annual power generation of about 12960 (kW·h), a variety of wetland plants in flower for sale, also has considerable economic benefits.