English Tittle:study On Design And Application Of Late Landfill Leachate Treatment Process

Late landfill leachate is a kind of high pollution,refractory poisonous and harmful waste water,it has high colority,accompanied by the stench,poor nutritional imbalance,biochemical characteristics.The author team for an urban domestic waste landfill site late more than 10 years of waste leachate as the research object,to seek an effective and economic process.This article mainly through laboratory test,field test data to determine the processing technology and the best operation parameters,as well as to the follow-up provide reference for the design of the project is running.The BAC-MBR-NF combined process was used to treat the landfill leachate,and the effect of the process in the landfill leachate treatment was studied.The main research contents and conclusions are as follows:(1)In the laboratory,the aerobic activated sludge test device was used to treat the late leachate to detect its biodegradability.,control reaction temperature 30 ~ 35 ?,DO 2 ~ 3mg/L,HRT 6d,Water COD concentration of 1770mg/L,NH4+-N concentration of 267mg/L,COD removal rate of 38%~43%,effluent COD concentration between 1000 ~ 1100mg/L,NH4+-N removal rate of 90%~96%,effluent NH4+-N concentration less than 25mg/L.(2)In the laboratory using activated carbon test device to deal with advanced leachate raw water to detect its wastewater COD adsorption effect,in 150 m L raw water were added 0.3g,1g,2g,3g,4g powdered activated carbon,stir for 3 minutes,static precipitation 3 hours,supernatant detection.The removal rate of COD in raw water was 29.42%,57.19%,64.98%,73.77% and 78.49 respectively.The powdered activated carbon has a good adsorption effect on macromolecular COD in leachate.(3)Using aerobic activated sludge test devices,control reaction temperature 30 ~ 35 ?,DO2 ~ 3 mg/L,HRT 6 d.Respectively to the reactor dosing 15 g,30 g of powder activated carbon,the raw water COD removal rate reached 72%,84% respectively.The result shows that the biological activated carbon process is better than the aerobic process.Under certain conditions,the organic matter removal efficiency is positively related to the amount of activated carbon.In the case of adding the 15 g,activated carbon,control of HRT,respectively 4 d,6 d,8 d,the removal rate of COD were 61%,72% and 75% respectively.It shows that taking HRT=6d is the most economical and efficient under this condition.(4)The BAC test results as the reference for the design and construction of volume 750m3 fand aerobic biological activated carbon tower reactor for the treatment of 150m3/d late landfill leachate.In the case of water temperature of 26~34 ?,when the influent COD 1500 ~ 2000mg/L,NH4+-N 200 ~ 300mg/L,after about 60 d of the debugging,effluent COD ? 700mg/L,NH4+-N? 30 mg/L,the removal rate reached more than 60%,88%,respectively,meeting design requirements.The concentration of COD and NH4+-N in BAC effluent was reduced to 500mg/L and 20mg/L by MBR treatment,achieving phased processing effect.(5)In the deep processing stage,using NF/RO test device to deal with biochemical effluent.NF in the feed water flow after 4 m3/h,operating pressure is 0.6 Mpa,COD,NH4+-N concentration in the case of around 500 mg/L,20 mg/L respectively,the effluent COD?100 mg/L,NH4+-N ?15 mg/L;RO in the feed water flow after 4 m3/h,operating pressure is 1.2 Mpa,COD,NH4+-N concentration in the case of around 500 mg/L,20 mg/L respectively,the effluent COD? 40 mg/L,NH4+-N ?15 mg/L.Both NF and RO meet emission requirements,and NF requires lower operating pressures and more economical.(6)BAC-MBR-NF process in the 150 m 3 /d late landfill leachate treatment project operation results show that the final effluent COD ? 100mg/L,NH4+-N ? 15mg/L,the effluent indicators of the effluent reached the standard of GB(16899-2008)for pollution control on the landfill site of municipal solid wast.and stable operation,Greatly save the area,the direct operating costs of 16.9 yuan per ton of water.