In this research, we developed integration and collaboration scenarios of sewage sludge and domestic waste incineration facilities in Wakayama City considering future population decline in 2010-2040. We also evaluated the reduction effects in energy consumption and greenhouse gas (GHG) emissions based on the scenarios to promote centralized treatment of sewage sludge, introduce low-carbon technologies into the treatment process, and combust the sewage sludge with domestic waste in waste incineration facilities. From the analysis, we reached the following conclusions: 1) Co-combustion of sewage sludge in waste incineration facilities brings energy saving and GHG reduction compared to centralized treatment of sludge. 2) In the co-combustion scenario, the utilization of exhaust heat recovered from waste incineration facility to dry the sewage sludge improves the reduction effects of environmental burdens. 3) To introduce a fuelization technology of sewage sludge into the centralized treatment facility can reduce GHG emissions by 101.9%.

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