Traitement du lixiviat « jeune » et concentré de lieux d'enfouissement technique par des filtres plantés aérés

“Young” landfill leachate, produced by the percolation of water through sites in operation at a landfill, is concentrated in organic matter, ammonia and metals, and is typically treated using intensive and conventional systems, like sequencing batch reactors. Studies have looked at treating “old” and less concentrated leachate, produced by capped sites at a landfill, by treatment wetlands. Few studies have investigated the treatment of landfill leachate using vertical, aerated planted filters, a hybrid technology similar to treatment wetlands fed at a higher than typical loading rate or trickling filters and biological, aerated filters fed at a lower than typical loading rate and with plants installed at the surface. Few studies have investigated the use of this technology specifically for the treatment of young landfill leachate as well. The objectives of this study were to 1) determine if vertical, aerated planted filters could efficiently treat young leachate BOD5, TSS, NH4 and zinc specifically to the point of respecting discharge requirements in Quebec, 2) characterize the effects of the plants on leachate treatment and the effects of the leachate on plant health, 3) quantify the denitrification achieved in pre-anoxic filters and 4) determine full-scale design criteria for a vertical, aerated planted filter. Five 430 L pilot-scale filters with 10 – 20 mm granite media were operated in parallel in a greenhouse for a total of 42 weeks during fall 2020 and spring through fall 2021. This report presents and discusses the results of treatment during the first 28 weeks of operation. Each filter was fed an average of 16 L m-2 d-1 of young leachate pretreated to reduce iron concentrations by an upflow anaerobic sludge blanket reactor, feeding each filter an average of 4.1 g BOD5 m-3 d-1.