A comparative life-cycle greenhouse gas (GHG) emission analysis between a proposed integrated sewage sludge (SS) and food waste (FW) management strategy and business-as-usual scenarios in Singapore was performed in this study. The proposed approach was derived based on the design of co-located water reclamation plant and waste-to-energy incineration plant in Tuas, in which the SS and FW are anaerobic co-digested. The ratio of SS and FW was selected to be 1:1 for optimal biogas production. The effects of the power substitution and methane production rate uncertainties were investigated. The life-cycle GHG emission results show that the proposed strategy has a 64.3% reduction when compared to the current SS and FW treatments, or a 2129 tonnes CO2-eq reduction potential per year.
Keywords Anaerobic co-digestion; Sewage sludge; Food waste; LCA; Greenhouse gas emission