Use of sequential extraction on anaerobically degraded municipal solid waste

The advantage of sequential extraction methods of analysis to assess degraded municipal solid waste (MSW) has been investigated. The objective of this study was to determine whether the sequential extraction methods can provide useful information on the distribution of heavy metals (Zn, Cu, Pb, Cr, Ni and Cd) in MSW in anaerobic conditions. It was found that the distribution of heavy metals is strongly influenced by certain solid phases, although it was difficult to identify properly the different chemical forms of heavy metals. Oxides/hydroxides, organic matters and sulphides appear to be important scavenging phases of heavy metals. A modified Tessier method, followed by an acid volatile sulphide (AVS) collection system, shows that the AVS is mainly dominated by two solid phases, iron and zinc sulphides.