Décontamination des résidus de contrôle de la pollution de l'air (RCPA) d'incinérateurs de déchets municipaux par lixiviation en milieu basique et adsorption sur tourbe

Abstract

Air pollution control residues (APCR) from municipal waste incinerators are usually considered as hazardous wastes because of their high contents in easily soluble Pb and other toxic metal contaminants. The objective of this research was to compare various techniques using Pb adsorption on Sphagnum peat moss (MT) for the treatment of alkaline leachates produced during the decontamination of various types of APCR including used lime (CU), electrofilter ashes (CE), and boiler ashes (CC). Regeneration tests of saturated MT using hydrochloric and sulphuric acids have revealed that excessive acid consumption (>250 kg acid/metric ton of treated APCR) are necessary for the elution of metals. However, the incineration of the saturated MT and its possible valorization represents an interesting way to explore for the management of the adsorbent. This method allows to reduce by a factor of 3 or 4 the mass of residues and increases in the same proportion the Pb content in the incinerated MT. Finally, the present study has highlighted that ion exchange on the anionic functional groups of MT would be one of the most important mechanisms implied in the Pb fixation on this natural sorbent during the treatment of very alkaline leachates (pH > 11) of APCR.Key words: lead, leaching, incinerator, air pollution control residues (APCR), removal, peat, adsorption, toxicity characteristic leaching procedure (TCLP).[Journal translation]