Biogas upgrading using bottom ash from the incineration of municipal solid waste (MSW) is especially
interesting for integrated treatment facilities as it would allow closing a complete loop in MSW management.
The aim of this research was to assess the interaction between bottom ash (BA) and biogas
from anaerobic digestion with the outlook of upgrading in terms of CO2 and H2S removal, with particle
size and bottom ash aging as the main variables. The finest fraction of fresh bottom ash (FBA) presented
the best performance, with a sorption capacity of 30e50 kg CO2$t
1 dry FBA. The sorption capacity of
weathered bottom ash (WBA) was lower than the recorded for the fresh material. From the results
obtained it can be stated that the CO2 absorption capacity of bottom ash mainly relies in the finest
fraction because of its larger surface area and higher CaO content. In what respect to H2S sorption
capacity, WBA presented a better performance, with values ranging 3.1e5.2 kg H2S∙t
1 dry WBA. In
addition to the energetic enhancement, the proposed technology also allows an immediate stabilization
and reuse of bottom ash as the leaching of heavy metals and metalloids remained under regulatory
limits.