Pilot Study On Synergistic Treatment Of Mixed Liquid Of Leachate And Sewage With Ammonia Stripping And Inverted A~2 /O Process

Due to complex components, soluble solid content, high concentrations of NH₃-N, low phosphorus content, big fluctuations of water quality and quantity, and the high toxicity, Landfill leachate have serious impact on the surrounding groundwater and surface water.Domestic landfill leachate treatment plan can be classified as outside processing and field processing. The outside processing is that landfill leachate access to collaborative treatment of town sewage treatment plant.Compared to field processing, outside processing have the advantage of save the investment of capital construction of independent processing system in the landfill . Due to the larger quantity, city sewage can have a buffer and dilution effect to the leachate. Simultaneously the nutritious substances in the city sewage can adjust the proportion of nutritious substances in the leachate ,such as phosphorus supplement . So that the leachate treatment effect can be effectively guaranteed .At present, many sewage treatment plant in the medium and small towns of Three Gorges Reservoir Area receive untreated leachate and treat them in the combined processing way.The abouchement of landfill leacheat changed the inflow quality of the town sewage treatment plant . The inhibited function of the high concentration of NH3-N and heavy metal ion to the activity of microorganism will reduce the organic pollutants degradation efficiency of biochemical system , consequently the effluent can not reach the emissions standards and produce risk of steady operation and manage to the sewage treatment plant.According to the domestic and foreign pretreatment technology research on landfill leachate and the research group on leachate physicochemical pretreatment technology research achievements my research group had,I choose the aeration stripping process which have the advantages of high Ammonia nitrogen removal efficiency and technical and economical optimization as the pretreatment technology to the inverted A²/O process and make experimental research on a pilot-scale.On this basis, through the study of the mixing ratio of the leachate and waste water, leachate access location and time effect on aeration stripping - inverted A²/O process treatment, discuss the inverted A²/O process operation mode and optimize the operation parameters of The aeration stripping process and Eventually get the optimal operation pattern of the aeration stripping - inverted A²/O process, so as to solve the problem that the effluent quality of Fuling District of Chongqing sewage treatment plant which collect landfill leachate can not be stable up to ( GB16889-2002 ) the first level of B target and provide technical guidance for product application of Leachate and Sewage with Synergistic Treatment. The main results and conclusions are as follows:(1) Comprehensive considering the aeration stripping efficiency,economic effects and corrosion-resisting property of equipment,the optimum range of the aeration stripping pretreatment: pH 10-11, aeration time 3-5h, air/liquid ratio 400 - 1200 ,and the temperature above 15℃.(2) Using the A²/O inversion process flow cooperative processing the mixed liquor of landfill leachate pre-treated by aeration stripping and municipal sewage,when the optimum mixing range within 1:20, effluent stability and reached the class I-B criteria . The optimum time range to access mixed liquor is 01:00 am - 10:00 am. When landfill leachate accessed to the anoxic tank,the treatment effect of A²/O inversion process flow is better than accessed to the anaerobic tank.(3) The optimum operation parameters of the aeration stripping and the A²/O inversion process flow: pH 10.5, air/liquid ratio 250, aeration time 4h, water temperature 15²5℃,the mixing ratio of landfill leachate and municipal sewage less than 1:20, landfill leachate accessed to the anoxic tank, external reflux ratio 100%, inner recycling ratio 200%,using continuous influent when landfill leachate and municipal sewage mixed, the mixing ratio can be improved at 01:00 am - 10:00 am.