IMMOBILIZATION OF FLY-ASH FROM MSW INCINERATORS AND ASH-MELTING FURNACES

In Japan, residue from the incineration of municipal solid waste - bot h fly ash and bottom ash - had legally been classified as ''municipal waste'' and accordingly had been disposed, in controlled landfill site s. In a revision implemented in April 1995, however, fly ash was recla ssified as a ''special-controlled municipal waste'' and it became mand atory to dispose of the substance in controlled landfill sites only af ter it had been stabilized to prevent the leaching of heavy metals. We have conducted comparative fly ash treatment tests with various comme rcially available stabilizing agents and cement. We have also develope d an inexpensive solidifying powder (SFPA, or Sumitomo Fine Powder Age nt) and verified its effectiveness. Furthermore, in a series of treatm ent tests with ash-melting a furnace fly ash having a very high rate o f heavy metal leaching such as 480 mg/l of lead, we confirmed that tre atments combining SFPA and ''special aging'' have superior performance controlling lead leaching under 0.05 mg/l. (C) 1997 Elsevier Science Ltd.