Hydrogen production from the organic fraction of municipal solid waste in anaerobic thermophilic acidogenesis: Influence of organic loading rate and microbial content of the solid waste

Abstract

Hydrogen production (HP) from the organic fraction of municipal solid waste (OFMSW) under thermophilic acidogenic conditions was studied. The effect of nine different organic loading rates (OLRs) (from 9 to 220g TVS/l/d) and hydraulic retention times (HRTs) (from 10d to 0.25d) was investigated. Normally, butyrate was the main acid product. The biogas produced was methane- and sulfide-free at all tested OLR. Increasing the OLR resulted in an increase in both the quantity and quality of hydrogen production, except at the maximum OLR tested (220g TVS/l/d). The maximum hydrogen content was 57% (v/v) at an OLR of 110g TVS/l/d (HRT=0.5d). HP was in the range of 0.1–5.7l H2/l/d. The results have clearly shown that the increase in OLR was directly correlated with HP and microbial activity. The bacterial concentration inside the reactor is strongly influenced by the content of microorganisms in the OFMSW.