Landfill Leachate Treatment by Evaporation

This paper reviews and extends understanding of evaporation/distillation as treatment for landfill leachate. Evaporation may produce condensate that is high quality and easier to dispose of than effluent from conventional leachate‐treatment processes with the volume of the concentrated residuals being a small fraction of the original leachate volume. Laboratory‐scale, one‐ and two‐step distillation experiments with pH adjustment were performed with ammonium acetate test solution and three leachate samples from older landfills. A single‐step, acidic distillation of the strongest leachate samples removed more than 95% of ionic impurities, except for volatile organic acids, which were removed at 85%. Two‐step acid‐base evaporation, or ammonia stripping coupled with evaporation, may effectively remove ammonia and volatile organic acids if present together in relatively high concentrations. A Monte Carlo analysis of the feasibility for energy‐self‐sufficient leachate evaporation via landfill methane combustion shows, theoretically, that there will be sufficient methane gas to vaporize leachate in a majority of modern landfill situations based on the limited published data and assuming uncorrelated input parameters. Balancing landfill leachate production to methane production may be tenuous for some landfill settings. Although the data developed here are limited, this investigation suggests that by‐product leachate and gas from landfill operations may be used beneficially in a novel, energy‐self‐sufficient treatment process.