Application Study Of Short-cut Nitrification And Denitrification MBR+RO Process For Treatment Of Landfill Leachate

MBR biofilm process and nanofiltration membrane and reverse osmosis membrane advanced treatment process are widely used in landfill leachate treatment,but high aerobic energy,high energy consumption,low biochemical treatment efficiency,and subsequent nanofiltration have also appeared in the process.Multi-stage treatment of membrane and reverse osmosis membrane,low water production efficiency and high membrane depreciation rate.In this paper,short-cut nitrification and denitrification start control,treatment efficiency and influencing factors of each treatment unit were treated with A/O/N+A/O+MBR ultrafiltration membrane+reverse osmosis process to treat leachate in Lin'an landfill.Through qualitative and quantitative analysis of DO,MLSS,SRT,mixture reflux ratio,pH,alkalinity and membrane operation related parameters,the following conclusions were obtained:?1?In the A/O/N process,the O-injector DO is 0.5 mg/L to 0.8 mg/L,and the N reactor DO is 1.5mg/L to 2.2 mg/L.The short-cut nitrification reaction is successfully initiated,and the N reactor is nitrous acid.The salt nitrogen accumulation rate is over 60%.?2?The system sludge concentration is 3500mg/L⁴500mg/L,the sludge age is 9d¹3d,the A reactor DO is less than 0.5mg/L,and the O reactor DO is 0.5mg/L⁰.8mg/L,N The reactor DO is 1.5mg/L to 2.2 mg/L,the mixed solution reflux ratio is 1100%,and the secondary oxygen-pouring tank is controlled to be 3 mg/L to 4 mg/L.The COD oxidation tank is adjusted for alkalinity to adjust the pH of the nitrification tank.From 7.6 to 8.2,short-range nitrification and denitrification were stably achieved in the first-class A/O/N under this condition.The nitrite nitrogen accumulation rate was over 85%,and the biochemical system COD,NH4+-N and TN removal rates were 95 respectively.%,98.2%,94.2%.The biochemical system reduced the aeration volume by about 20%and the carbon source by 32%before and after the short-range nitrification,and the remaining sludge production was reduced by about35%.?3?The flux of MBR ultrafiltration membrane is affected by inlet water temperature,flow rate,sludge concentration and continuous running time.The higher the influent temperature,the faster the flow rate and the smaller the sludge concentration,the higher the ultrafiltration membrane flux.The longer the continuous running time,the faster the membrane flux drops.?4?Reverse osmosis membrane flux is affected by inlet water temperature,inlet pressure and running time.The higher the influent temperature in the reverse osmosis membrane parameter range,the higher the influent pressure and the higher the reverse osmosis membrane flux.The lower the water production rate of reverse osmosis membrane,the higher the interception efficiency of pollutants.When the water production rate is 75%to 80%,the interception efficiency of COD,NH₄⁺-N and TN is 79%to82%,76%to 78%,82%to 84%.