Research And Demonstration Of Decentralized Rural Sewage Treatment Technology Of Biological And Ecological

This study was based on the Nanjing’s climatic conditions and rural sewage treatment characteristics and needs, to carry out decentralized rural sewage "anaerobic methane-waterfall aeration contact oxidation-constructed wetland" bio-ecological combination technology research and demonstration. Combination of biological and ecological processes of biological and ecological engineering methods combine both can cost savings, and achieve a stable nitrogen and phosphorus removal effect. Preclude the use of a combination of a small pilot-scale process of rural sewage treatment. Artificial wetland unit performance and organics removal of nitrogen and phosphorus removal performance study. Analysis of the low temperature period wetland units of different fillers, different plants and phosphorus removal machine off affect performance, optimized matching to determine the plant constructed wetland system and better packing mechanism Nanjing fall and winter seasons. And on this basis, the construction of a demonstration project, run by the effect of the environmental benefits, the project’s economic indicators were evaluated. The following conclusions:(1) Combined process of anaerobic biological segment unit with a stable, efficient characteristic of the reactor. Role is to effectively reduce the subsequent aerobic process of organic load. Aerobic using natural or water oxygenation, to achieve a high efficiency and low costs Ecology section with subsurface constructed wetland technology, Through the rational allocation matrix filler and plants, forming an efficient ecological purification system by aquatic plants, aquatic animals and micro-organisms constituted. Combination of biological and ecological processes, biological and ecological processes to achieve the complementary advantages, make up the conventional process is not complete and pure nitrogen and phosphorus removal ecological processes of climate change impact, such as lack of treatment effect of instability.(2) Select a different fillers and different plants constructed wetland system, for the removal of organic matter and nutrient removal performance properties vary. Under the same circumstances breeding plants (water celery), to a combination of cinder-based filler filler system nitrogen phosphorus and nitrogen removal performance than gravel packing system; In the case of the same matrix filler (based on a combination of cinder filler), planting water celery Grassleaf Sweelflag Rhizome phosphorus and nitrogen removal performance is better than planting, planting Grassleaf Sweelflag Rhizome of COD removal performance of minor water than planting celery.(3) Grassleaf Sweelflag Rhizome and celery are low water period, wetland unit has a better alternative contamination removal performance of wetland plants, cinder filler to match the combination of celery and water base filler is optimum portfolio selection wetlands. This combination is constructed wetland sewage treatment system, NH4+-N removal rate was 78.8%, with an average total phosphorus removal rate was 79.6%, the average COD removal efficiency was 64.7%.(4)Construction of the demonstration project in the fall and winter seasons during operation, stable effluent water quality, COD basically stable at between 15.2-38.3mg/L, ammonia nitrogen stable between 2.1～4.9mg/L, total phosphorus stable at 0.18～0.48mg/L between, in line with the "urban sewage treatment plant pollutant discharge standard" (GB18918-2002) a level B standard. Combined process system for COD, ammonia nitrogen, total phosphorus average removal were 86.8%,86.9% and 87.7%. Using this combination of biological and ecological processes to build a demonstration project in the fall and winter low temperatures can still maintain a good treatment effect of pollutants.(5)Wetlands filler using cinder Nanjing widely available as the basis for filler, improved removal of pollutants, while reducing solid waste.(6) Combined process of constructing a demonstration project, the annual reduction COD2250kg, nitrogen 310kg, phosphorus 40kg, Construction of 8.335 billion yuan direct costs, excluding labor operating costs for 0.228 yuan/ton. biogas and anaerobic aquatic and wetland planting vegetables. Combined Process have adapted to local conditions, cost-effective, easy to manage, and has many other advantages of energy saving effect, fully embodies the idea of sustainable development.