Description of the organic wastes
Slurry biogas residue was obtained from a municipal biogas plant in Västerås where the biogas is
produced from source-separated household waste, ley crop and fat removal sludge from restaurants.
The sewage sludge was obtained from the municipal wastewater treatment plant in Västerås that treats
sewage from 118,000 p.e. yielding 12,000 tonnes dewatered (25% d.m.) sludge per year. Influent raw
wastewater is pre-precipitated with iron sulphate, biologically treated by an activated sludge process with
pre-denitrification supported with glycol as external carbon and energy source. Excess sludge is
anaerobically digested to reduce its volume, make the product hygienic and produce biogas.