Trace element release from combustion ash co-disposed with municipal solid waste

Abstract

Ash products from coal and municipal solid waste combustion constitute a waste stream with characteristics that, unless recycled, require specific disposal practices. Although traditional disposal involves ash placement in a cell dedicated solely for the ash (monofill), new regulations for the management of coal combustion residues in the US might lead to more co-disposal of these residues with unburned municipal solid waste (MSW) that has not been combusted or otherwise processed. Both monofill and co-disposal practices are currently utilized for MSW incineration ash in the US. Column tests were performed using landfill leachate as a leaching solution to simulate co-disposal conditions of ash with MSW, while DI water was used to simulate monofilling. Mobility of As, B and V from coal fly ash was enhanced in the presence of landfill leachate in both batch and column tests, and a similar trend was observed for Cd and Mo release from MSW incineration ash. For several elements, release was greater with the column procedure relative to the batch procedure. The results suggest that long-term implications of co-disposal should be factored into decisions regarding which disposal scenario to pursue.