Anaerobic Digestion of Municipal Solid Wastes

This paper discusses the present state of municipal solid waste (MSW) disposal in Brazil , focusing on the particular situation in the City of Sao Paulo, and indicates the future trend of the anaerobic digestion approach for this residue. Also, some results, representative of several studies developed at IPT on anaerobic digestion of MSW mixed with primary sewage sludge, are presented. These studies were conducted using agitated reactors of 2 or 8 liters capacity, continuously operated at 35°C and in the pH range 6.8 to 7.2. The studies were on: start-up of reactors, MSW to sewage sludge ratio, organic loading rate and hydraulic retention time. The results presented in this paper indicate the great interest in achieving anaerobic digestion of MSW in presence of sewage sludge, utilizing reactors with high solids content, which is the approach already observed, and certainly will be developed in the future.