Anaerobic digestion of the mechanically sorted organic fraction of a municipal solid waste and its co-digestion with manure in packed-bed biofilm systems under batch conditions

Packed-bed systems, consisting of 0.5 L-flask filled with tire chips or ceramic cubes, were employed in the wet batch mesophilic anaerobic digestion of a mechanically sorted organic fraction of a municipal solid waste and in its co-digestion with manure. High methane production only occurred in the latter case. Successive batch experiments demonstrated the advantages of packed-bed biofilm systems, which displayed significantly higher methane production yields with no lag-phases. Tire chips, i.e. a non-cost recyclable non-biodegradable material, provide results similar to those of ceramic cubes. The highest methane yields were achieved in the bioreactors packed with tire chips in the presence of a mixture in which the VS provided by the municipal waste represented 48% of the total waste VS. Under such conditions, the methane yield was about 70 ml/g volatile solids, representing about the 42% of the biochemical methane potential, and the 41% of the initial VS were removed.