Microbial synergies in co-digestion of food waste and wastewater sludge: pathways to energy recovery and emission reduction

Abstract

Food waste (FW) and wastewater sludge (WS) from treatment plants require sustainable treatment techniques such as anaerobic co-digestion (AcoD), to generate renewable energy and support climate change mitigation. AcoD offers a benefit; it reduces greenhouse gas (GHG) emissions, particularly methane, and simultaneously produces renewable biogas, which can be converted into electricity and heat, generating revenue and supporting economic growth. The implementation of AcoD is most advanced in regions with supportive waste management and energy recovery incentives, where co-digestion of FW with WS has become a viable pathway for both environmental and economic gains. AcoD operational energy demands exist, the electricity generated from methane combustion significantly offsets these costs, improving the energy balance by approximately ∼93–196 %, and contributing to GHG emission reductions of up to 97 %. This review highlights the economic feasibility and environmental benefits of the AcoD system, emphasizing their role in electricity revenue generation and broader GHG offsetting. Moreover, the findings underscore the importance of a policy framework that supports AcoD deployment through incentives and regulatory mechanisms. Life cycle assessment (LCA) is crucial for quantifying the net environmental impact and informing decisions on AcoD adoption. By advancing AcoD technologies and integration into national climate and waste strategies, policymakers can promote circular economic practices while significantly reducing the global warming potential (GWP) of organic waste treatments.