Biogasification of Municipal Solid Wastes

A series of experiments on the anaerobic digestion of the organic fraction of municipal refuse was performed. The refuse fraction used in the study was one of the portions segregated in a resource recovery system developed at the University of California, Berkeley. The scale of experiments includes 4, 9, and 1600-L digesters. The refuse used as feed was enriched by the addition of raw sewage sludge in various ratios, i.e., from 0–100 percent of the total volatile solids. No other sources of nutrients or chemicals for pH control were introduced into the reactors. Organic loading rates ranging from 1.1–6.4 g of volatile solids/L•d. Typical hydraulic detention times were 15 to 30 days. Temperatures were kept within the range of 72–104 F (22–40 C). Digestion efficiency was based on energy conversion and gas production.