BMP EVALUATION OF INTERMEDIATE AND FINAL OUTPUTS FROM BIOSTABILISATION MBT

At the European level, mechanical biological treatment (MBT) approaches are being used to manage the residual municipal waste (RMW) in order to promote the prevention or reduction of potential environmental impacts of landfilling. In the biostabilisation MBT, a mechanical selection is performed on the RMW to separate (1) the oversize flow to be processed as waste-derived fuel or directly landfilled and (2) the undersize flow (rich in organic fraction) that is partially biodegraded to obtain a stabilised output destined for landfilling. This study aimed at increasing the knowledge of the potential biomethane generation related to intermediate and final outputs from the biostabilisation MBT. Referring to a specific biostabilisation MBT process, biochemical methane potential (BMP) test series, along with initial and final characterisations of substrates and digestates, were conducted on: (1) the intermediate output represented by the mechanically separated, undersize organic fraction from RMW (us-OFRMW); (2) the final output represented by the biostabilised organic fraction from RMW (bios-OFRMW), derived from the aerobic biostabilisation of us-OFRMW; and (3) the portion of organic fraction that was still contained, based on a conducted compositional analysis, in the further final output represented by the mechanically separated, oversize RMW (os-OFRMW). Both final outputs have been disposed of at a landfill site for non-hazardous waste located in the Marche Region (Central Italy). The resulting BMPs were, in decreasing order, 445.6, 272.0, and 143.4 Nml CH4 g VS-1 for the us-OFRMW, the os-OFRMW, and the bios-OFRMW, respectively.