Foodwaste as a co-substrate in a fed-batch anaerobic biowaste digester for constant biogas supply

摘要

The use of foodwaste as a supplementary substrate for an anaerobic municipal biowaste digesternduring night times and as the sole substrate during weeks ends, when no biowaste suspensionnwas available was studied in order to equilibrate biogas production. Assays were performed innsemi-continuously fed laboratory reactors with real substrates, simulating practical feednconditions. Biogas production of biowaste or foodwaste reached 0.39 or 0.52m3n·kg21nCODadded,nwith an average methane content of 62–66%, respectively. By foodwaste co-digestion during thennight in a semi-continuously fed bioreactor, the total biogas production of the reactor increasednby 21–37% compared to biogas production during biowaste-only-fed periods during the day andnno feeding during the night. After three weeks of supplemenary foodwaste digestion during thennights and during week ends, the COD elimination efficiency of the reactor reached the samenlevel as in biowaste-only-fed periods (51–65%). During co-digestion of foodwaste with biowaste,nthe volatile solids elimination efficiency was between 62–65%, which was insignificantly lessncompared to the volatile solids elimination during biowaste-only-fed periods (63–68%).