Integrated treatment of food waste with wastewater and sewage sludge: Energy and carbon footprint analysis with economic implications

Food waste (FW) is a primary constituent of solid waste and its adequate management is a global challenge. Instead of disposal in landfills, integrated treatment of FW with wastewater (WW) can diminish both environmental and economic burdens. Utilizing steady-state modelling and life cycle assessment techniques, this study investigated the prospects of FW integration with biological WW treatment in terms of WW treatment performance, net energy and carbon footprint and economics of the process. The explored scenarios include co-disposal and treatment with WW by using FW disposers and anaerobic co-digestion with sewage sludge in Hong Kong. Compared to the existing WW and FW treatment, the integrated scenarios significantly improved the energy balance (similar to 83-126%), net greenhouse gas emissions (similar to 90%), and economics of operation, with permissible impact on WW treatment performance. Therefore, utilizing the surplus capacity of the existing WW treatment facilities, these integrated scenarios are a promising solution for sustainable development.