Environmental performance of dewatered sewage sludge digestate utilization based on life cycle assessment

• DOI: 10.1016/j.wasman.2021.11.005
• Publication Date: 2021-11-17T22:21:16Z
• Authors: Jouni Havukainen; Ali Saud; Thomas Fruergaard...; Petteri Peltola; Mika Horttanainen
• Keywords: Combustion; Life Cycle Assessment; /dk/atira/pure/sustainabledevelopmentgoals/responsible_consumption_and_production; name=SDG 12 - Responsible Consumption and Production; 7. Clean energy; 01 natural sciences; 12. Responsible consumption; /dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energy; name=SDG 7 - Affordable and Clean Energy; 11. Sustainability; Animals; Cities; Sewage sludge; Innovation; 0105 earth and related environmental sciences; Life Cycle Stages; Sewage; Composting; SDG 11 - Sustainable Cities and Communities; 6. Clean water; 13. Climate action; and Infrastructure; SDG 12 - Responsible Consumption and Production; SDG 9 - Industry; Pyrolysis

Due to the global trend of urbanization, the amount of sewage water is increasing in cities. This calls for efficient treatment of the resulting sewage sludge. To date, in the 27 European Union member countries (EU-27), the prevailing treatment method is application on arable land. Anaerobic digestion is one of the treatment methods being increasingly used nowadays. However, the resulting digestate requires further utilization. Therefore, in this study, the environmental performance of composting, combustion, and pyrolysis options for dewatered sewage sludge digestate is evaluated based on a life cycle assessment. The results show that digestate combustion and composting performed better than pyrolysis for most of the selected impact categories. However, pyrolysis of sewage sludge is still under development, and there are, to some degree, uncertainties in the data related to this technology; thus, more information for the performance assessment of pyrolysis is still required.