Co-digestion of intermediate landfill leachate and sewage sludge as a method of leachate utilization

The biogas yield obtained from the co-fermentation of a 20:1 sewage sludge: intermediate leachate mixture was 1.30 m3 per kg of removed volatile solids (VS), while that from a 10:1 mixture was 1.24 m3 per kg of removed VS. These values exceeded the biogas yield for the sludge alone by 13% and 8%, respectively. The leachate addition influenced the proportion of methane to a minor extent. Increased methane yields of 16.9% and 6.2% per kg of removed VS were found for the two sewage sluge:intermediate leachate mixtures, respectively.