Experimental Study On Landfill Leachate Treatment By Evaporation Method

Landfill leachate is a major hidden danger for water resource and conventionalwater treatment process has been difficult to meet the water quality and safetyrequirements. It has become nowadays research priority to look for an efficienttechnology to treat landfill leachate.Bench-scale test and production process were adopted by this paper, and thesubject investigated were landfill leachate from early, middle, and old age. Removalefficiency of contamination by evaporation, and the influence of pH value to theremoval efficiency were studied. EEM technique was used to analyze the DOM ofcondensate and landfill leachate form different periods, and group technology ofMVR was adopted to treat landfill leachate from old age.The results showed that the trend that the volatilization of CODCr, TOC, NH3-Nand TDS from landfill leachates with different periods were highest in the earlyevaporation stage, greatly reduced in the middle evaporation stage and slightlyraised in the last evaporation stage, and95.6%,98.5%and97.3%CODCrweremaintained in concentrated solution when concentration factor reached10. Thevolatilization of contamination was significantly effected by pH value. Less CODCrvolatile content and much more NH3-N volatile contents of landfill leachate wereshowed in the alkaline conditions. No more CODCrvolatile content and much lessNH3-N volatile contents were showed in the acidic condition. The condensate liquidof old age landfill leachate achieved the standard of “Standard for Pollution Controlon the Landfill Site of Municipal Solid Waste”(GB16889-2008) to theenvironmentally sensitive areas.The DOM of landfill leachate changed remarkable with the time of the landfill,from tryptophan and dissolved microorganism by-product relate to microbialmetabolism with simple molecular structure into humic acid and fulvic acidmaterials with complex molecular structure. Only minor amounts tryptophan anddissolved microorganism by-product but no humic acid and fulvic acid materialswere found in condensate liquid when landfill leachate was treated by evaporation,but not humic acid and fulvic acid materials, and the difficult problem of humic acidand fulvic acid materials cannot be treated was solved easily. The probability that landfill leachate could be evaporated consecutively wasproved by dynamic test. Condensate liquid quality had met the standard of “Standardfor Pollution Control on the Landfill Site of Municipal Solid Waste”(GB16889-2008) to the environmentally sensitive areas and generic areas,respectively.The water quality of condensate liquid of landfill leachate treated by MVRintegrated process achieved the standard of “Standard for Pollution Control on theLandfill Site of Municipal Solid Waste”(GB16889-2008) to the environmentallysensitive areas, and the condensate liquid could be applied to industrial water andurban miscellaneous water. Concentrated solution could be treated safety aftercuring process.