| Based on the bio-chemical effluent of landfill leachate as raw water,that the experiment of a combined process of “flocculation-catalytic and ozonization-biological aerated filter ” was conducted for the treatment effect of bio-chemical landfill leachate has been studied in this paper.The process performance to treat landfill leachate of the three combined process were studied and discussed,after monitoring the CODCr,NH4+-N and chromaticity of infulent and effluent,the three main factors of combined process was investigated and analyzed.According to the experimental studies,the main conclusions can be drew as following:1.Coagulation sedimentation pretreatment dynamic test:(1)when the Polymeric ferric sulfate(PFS)was used as coagulant: the optimum dosage was0.6g/L,and the average removal Removal amountrates of CODCr and chromaticity was 68.8% and 85.9 % in stable operation,respectively,and the unit cost of sewage treatment is 0.72 yuan;(2)when the Polyaluminium chloride(PAC)was used as coagulant: the optimum dosage was 0.8 g/L,and the average removal rates of CODCr and chromaticity was 41.0 % and 71.3% in stable operation,respectively,the unit cost of sewage treatment is 0.92 yuan;(3)when the Polyaluminium ferric chloride(PAFC)was used as coagulant,the optimum dosage was 1.0 g/L,and the average removal rates of CODCr and chromaticity was 37.7% and 77.0% in stable operation,respectively,processing cost is 0.93 yuan;Considering the treatment effect and economic cost,the best coagulant was PFS,and the effluent pH was between 3.5~4.5.2.Advanced treatment of ozone catalytic oxidation:(1)Static test: water consumption of each experiment was 200 m L,the catalyst is a self-made supported activated carbon catalyst: ? The optimum operating conditions of ozone oxidation were the ozone dosage was 75mg/L,ozone contact time was 90 min,influent pH = 9,catalyst dosage was 1g,the average removal rates of CODCr and chromaticity was 21.1% and 66.0%,respectively;? The optimum operating conditions of activated carbon(AC)catalytic ozonation were the ozone dosage was 90mg/L,ozone contact time was 90 min,influent pH = 9,catalyst dosage was 1g,the average removal rates of CODCr and chromaticity was29.0% and 90.1%,respectively;? Supported activated carbon catalyzed ozone oxidation,activated carbon supported copper oxide(CuO/AC)was the best,when the ozone dosage was 90 mg/L,ozone contact time was 90 min,influent pH = 9,catalyst dosage was 1g,the average removal rates of CODCrand chromaticity was41.7% and 95.9%,respectively;(2)Dynamic test: through the comparative study of static experiments,CuO/AC was selected as the catalyst of ozone,when the ozone dosage was 90mg/L,ozone contact time was 90 min,influent pH = 9,catalyst dosage was 5 g/L,the average removal rates of CODCr and chromaticity was 42.3% and 95.8%,respectively,and the effluent pH was between 6.8~7.5.3.Biological treatment dynamic test: the optimal operating condition ofbiological aerated filter(BAF)process was HRT=9.2 h,concentration of dissolved oxygen was 5 ? 0.1mg/L,influent pH was 7,and the average removal rates of CODCr and NH4+-N was 37.7% and 83.8%,respectively.Under the optimal conditions and stable operation.4.A combined process of coagulation-catalytic ozonization-biological aerated filter was conducted for the advanced treatment of landfill leachate under the optimal conditions and stable operation,the average removal rates of chromaticity,CODCr,and NH4+-N was 99.5%,88.5% and 95.2% in stable operation,respectively;the average chromaticity was 4.2 times.The average concentration of CODCr was 74.6 mg/L,the average concentration of NH4+-N was 0.97 mg/L and4.2 times,respectively.Chromaticity,CODCr,and NH4+-N can meet the direct discharge limits of Standard for Pollution Control on the Landfill Site for Domestic waste(GB16889-2008)and can be reached the direct discharge water requirements for existing enterprises.The cost of the combined process is 2.03 yuan per ton of water. |
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