CHARACTERIZATION OF MUNICIPAL WASTE COMBUSTION AIR-POLLUTION CONTROL RESIDUES AS A FUNCTION OF PARTICLE-SIZE

Air Pollution Control (APC) residues from Municipal Waste Combustion ( MWC) typically contain high concentrations of potentially toxic metals . APC residues, consisting of fly ash and lime spray drier scrubber re sidue, were sieve separated into six size fractions. Residue character ization included physical and morphological classification and chemica l speciation. Elemental distributions as a function of particle size i ndicated parabolic distributions for matrix species and sigmoidal dist ributions for volatile species. Unreacted lime in the scrubber residue preferentially was present in the smallest fractions which greatly al tered the elemental distribution profiles. Mathematical correction for this highly water soluble portion of the residue normalized the data which showed extreme similarity between facilities. Parabolic profiles became nearly linear with negative slopes and sigmoidal trends were t ransformed into exponential curves. This included adjusted lead concen trations approaching 2 wt% and zinc concentrations up to 8 wt% in the smallest fractions.