Improving UV Transmittance of Biologically Treated Landfill Leachate

Landfills are typically required to pretreat leachate before sending it to a publicly owned treatment works. Many landfill pretreatment systems involve biological treatment and metals precipitation. After biological treatment the leachate still retains a high content of recalcitrant organic carbon. Traditionally, residual organics would not pose a concern to wastewater treatment facilities receiving treated leachate; however, as wastewater treatment plants increasingly employ ultraviolet (UV) disinfection, more landfills must meet UV transmittance as high as 65% for combined treated municipal wastewater and pretreated leachate. This study evaluated a number of treatment technologies (Fenton’s reagent, ozone and ozone with hydrogen peroxide oxidation, persulfate radical oxidation, titanium catalyst advanced oxidation, chemical precipitation, zeolite adsorption and membrane filtration) for improving UV transmittance of biologically treated leachate from two landfills. Nanofiltration and reverse osmosis, with or without a secondary absorptive media, were the most effective methods investigated in this study, with ozone being the least effective.