Energy Valorisation of Wastewater Treatment Plant Sludge through Thermal Gasification: An Economic Perspective

The technical-economic analysis was carried out for the production of sludge-derived fuel from a municipal wastewater treatment plant (WWTP). The baseline for the analysis consists of a sludge drying plant, processing 6 m3 of sludge per day and producing a total of about 1 m3 of combustible material with 8% of moisture and a higher calorific power of 18.702 MJ/kg. The transformation of biofuel into energy translates into an electricity production of about 108 kW per 100 kg of sludge. The project in the baseline scenario demonstrated feasibility with a payback time of about six years.