Pretreating Landfill Leachate with Biomass Boiler Ash

Abstract

Landfill leachate was applied at a rate of 1 gpd/sq ft (4 cm/d) for eight weeks to columns containing boiler ash recovered from a biomass-fired (90% wood, 10% coal) boiler. Both influent and effluent samples were analyzed for chemical oxygen demand (COD), total suspended solids (TSS), pH, conductivity, and certain metals. Overall, the ash removed nearly 38% of the COD, and suspended solids removal approached 89%. Further, the results show that the ash favorably raised the leachate pH, removed substantial metals, and only slightly increased conductivity. If the predominantly wood-based ash can be incorporated into the landfill, either as daily cover or as a secondary liner to the landfill liner, then the treatability of leachate can be enhanced.