LEACHING DYNAMICS STUDIES OF MUNICIPAL SOLID-WASTE INCINERATOR ASH

An assessment of the short- and long-term hazards from municipal solid waste incinerator (MSWI) ash is made through the elemental analysis o f 40 to 50 elements in the ash and leachates produced by several leach ing procedures. The ash was analyzed using neutron activation analysis (NAA) and x-ray fluorescence (XRF). The leachates were analyzed using NAA and inductively-coupled plasma atomic emission spectroscopy (lCP) . The leaching dynamics of an ash monofill were modelled with a series of extractions using simulated acid rain. An initial spike of the met als Ag, Ba, Be, Cr, Cu, Mo, Pb, Sr, and Zn in the leachates appears to be the greatest hazard posed by MSWI ash monofills. The elements As, Cd, Cu, Hg, Pb, S, and Zn were identified as potential long term hazar ds utilizing a sequential extraction procedure which approximates the total amount of the elements available over the lifetime of the monofi ll. The pH of the resulting leachate is the single greatest factor gov erning the concentration of metals in solution, more important than th e concentration of the element in the ash. These results are applied t o an assessment of the suitability of the Toxicity Characteristic Leac hing Procedure (TCLP) in measuring leaching potential of an MSWI ash m onofill.