The Productive Study Of Landfill Leachate Treatment By MBR+NF+RO Processes

When Standard for Pollution Control on the Landfill Site of Municipal SolidWaste（GB16889-2008）has been promulgated，it sets a more strict demand on thewater quality of treated landfill leachate and it alsostipulates that all the landfillshould dispose of landfill leachate to meet the limit of the new standards from July1,2011，which put forward higher requirements on leachate treatment process.In April,2010, the standard, Leachate Treatment Project Technical Specificationof Municipal Solid Waste Landfill, has been formally implemented. It puts forward"biochemical+membrane " as the principle treatment process, so the method hasbeen identified as the standardized process. At the same time, the treatment effect ofthe process in the practical application has been proved satisfactory, as well as thelower costs of the investment, operation and maintenance than full-membraneprocess.It is Suitable for the situation of China and widely used in recent years in ourcountry.Through the research on the treatment effect of landfill leachate byMBR+NF+RO process in the debugging and initial operation of a real project, thepaper puts forward some optimal advice and the conclusions are as follows:1). Water-quality index (COD, NH3-N, TN and pH) of leachate in linearposition in regulation pool does not vary gradually, it is completely mixed. Inregulation pool, when the COD is below2500mg/L, the NH3-N is below350mg/L,the TN is below500mg/L, the COD removal rate can reach56%within49days insummer, but there is no effect on removal of NH3-N and TN.2). During the debugging, because of the low DO and F/M in the Aerobicbiological reactor, filamentous sludge bulking occurs in biochemical reactor of MBRsystem. The deterioration of sludge do not have a significant impact on effluent waterquality of MBR system, the removal rate of COD, NH3-N and TN can reach87%,98%,92%respectively. But the deterioration of sludge will accelerate the membranefouling of ultrafiltration membrane and reduce water production rate. In the late stageof debugging, Water production was restored by chemical cleaning.3). The removal rate of COD and TN in NF system can reach95%and70%respectively, but there is no effect on the removal of NH3-N. The NF system hasstrong desalination capacity at low concentrations:when the water conductivity in300~340μm/cm range, the removal rate reached77%. 4). When the influent leachate pollutant concentration is lower in the"MBR+NF+RO" process, the effluent quality of NF system could meet emissionsstandards. So the RO system should be closed temporarily, in order to save powerconsumption and prolong the service life of RO system.