Method for the breakdown and recycling of solid urban waste by anaerobic fermentation

Abstract

The urban waste is crushed (2) to dimensions no greater than 5 cm and intimately mixed (5) with a aqueous suspension of biological sludge preconditioned at a temperature of from 40 to 100.degree. C. (6) and having a dry content of from 3 to 30% by weight, the suspension thus obtained, inoculated with bacterial strains (7) which can effect anaerobic break-down, being supplied to a closed fermentation cell (11, 12, 13) operated as a fluidised bed and being kept under anaerobic fermentation conditions in the cell until the emission of biogas has effectively ceased. In the fermentation cell the suspension percolates through filtration means constituted by a non-woven textile covering the walls and the base of the cell and the flow of percolated suspension is recycled to the cell. The filtration means also facilitate the separation of the biogas evolved.

Dependencies are inferred from the claim text.