Landfill Leachate Treatment Process

Landfill Leachate is a high concentration of complex organic wastewater with the big change in water quality..The paper introduced the leachate sources. characteristics of hazards,and the main treatment technologies.It needs to be addressed with a combination of physical-chemical and biochemical technologies according to its quality,and quantity characteristics.Physical technologies pretreating leachate can effectively reduce the COD_Cr,ammonia,heavy metals,and color,for its following biological treatment process to create a good entironment.On basis of domestic and abroad references,there have been some integrative and systematic researches of treating landfill leachate technologies and their principles concerned using electrolysis,Fenton oxidation process,up-flow anaerobic sludge bed.anoxic/oxic activated sludge process,sequencing batch reactor and membrane separation technologies in this dissertation.The results treanting landfill leachate using electrolysis process showed that the effect of time,current densities,electrode distances on COD_Cr and NH₃-N removal efficiency.The effect of electrolysis on COD_Cr removal efficiency was better than that of NH₃-N.The relationship between the factors of electrolysis time.current densities and COD_Cr and NH₃-N removal efficiency was positive,namely the more the electrolysis time.current densities was.the more the COD_Cr and NH₃-N removal efficiency was.The effect of electrolysis on COD_Cr removal efficiency,however. was lower along with the electrode distances increased.The results treanting landfill leachate using Fenton oxidation process(Fenton) showed that Fenton as leachate pretreatment methods can the effectively reduce COD_Cr and NH₃-N of the leachate,which were 60.6%and 97.7%respectively.The results enhancement applying active carbon to Fenton oxidation process and Sequencing batch reactor treanting landfill leachate showed that the COD-(Cr) and NH₃-N removal efficiency under the active carbon concentration(1200～1400mg/L), aeration time(14h) were 81.8%and 78.2%respectively.After landfill leachate passing through floatation tank,up-flow anaerobic sludge bed(UASB),anoxic/oxic activated sludge process(A/O) in turn,the removal efficiency of COD_Cr,BOD₅,NH₃-N and SS of the leachate were 15%,60%,60%; 15%,70%,65%;10%,42%,60%:60%,20%,30%respectively.After landfill leachate passing through ultrafiltration(UF),nanofiltration(NF), and reverse osmosis(RO) in turn,the removal efficiency of COD_Cr,BOD₅.NH₃-N and of the landfill leachate were 65%,70%,70%;70%,72%,70%;80%,70%,70% respectively,which the COD_Cr and NH₃-N concentration of water from RO exit were 26mg/L and 3 mg / L which was in accordance with the "standard for pollution control on the landfill site for domesticwaste"(GB16889-2008) -- the emission standard.