Chemical characterization of ash produced during combustion of refuse-derived fuel with coal

Bottom ash, electrostatic precipitator, and suspended stack particulate matter samples were collected when coal alone and mixtures of coal and refuse-derived fuel (RDF) were combusted in a municipal power plant. Chemical analyses indicated that levels of bromine, chromium, nickel, lead, antimony, tin, and other elements in bottom ash were two to five times higher when RDF was fired with coal. Coal/RDF combustion appeared to increase the average levels of most metals in precipitator flyash, although increases of a factor of two or more were not observed. The most prominent increases in trace element concentrations in stack flyash resulting from cocombustion were for Br, Pb, Sb, cadmium, Sn, and zinc. The magnitude of the increases in element levels in ash streams does not appear sufficient to warrant any greater environmental concern for ash from firing coal/RDF mixtures than for burning coal only.