Emission characteristics of particulate matter and heavy metals from small incinerators and boilers

The characteristics of particulate matter (PM) emission such as the estimation of emission factors, size distributions and of heavy metal emission from small-size incinerators and boilers have been investigated. In PM-10 emission, a fine mode was found in the formation of sub-micron PM by growth of nucleated aerosol of metal vapor, having a bimodal particle size distribution in overall size range. The emission ratios of PM-10 to TPM (total PM) from boilers and incinerators ranged from 29% to 62% and 10% to 84%, respectively, which resulted in more and larger sized PM emission due to poorer combustion from solid waste incinerators than boilers. The targeted metals were copper, cadmium, manganese, chromium, magnesium, lead, zinc and copper, and their contents in bottom ash, fly ash and dust (PM) were compared. More volatile metals such as cadmium, lead and zinc showed higher enrichment in PM emitted through stack than bottom ashes. Cadmium, copper, lead and zinc on the fine PM under 2.5 μm accounted for approximately 90% of the total mass of each metal in PM-10. The effects of chlorine concentration and temperature on such metals emission were also observed due to their volatility changes.