Life cycle assessment of a commercial-scale valorized grocery food waste product and its potential use as a sustainable feed input for egg production

Food waste is a major sustainability challenge in modern society. Livestock production also presents core sustainability challenges, notably due to its demand for feed inputs and associated impacts. Directly valorizing food waste to livestock feed at a commercial scale has hence emerged as a potential strategy to solve both problems. However, case studies of such systems are limited, particularly in western countries, representing an important knowledge gap. This study reports a cradle-to-gate Life Cycle Assessment of a commercial-scale grocery waste-to-poultry feed input production system based in Pennsylvania, and the use of the resultant feed product for egg production in Canada. Findings for the valorized input product system showed a net environmental benefit for climate change and eutrophication impact categories due to avoided landfill emissions when no landfill gas collection is assumed. Using feed containing 5 % valorized product in egg production reduced the life cycle environmental impacts of conventional Canadian eggs in 10 out of 11 impact categories, including a 17 % impact reduction in climate change at the 20-year horizon. However, fossil fuel depletion saw a 57 % increase in impacts, due to process and technical inefficiencies in the studied product system and Pennsylvania's reliance on fossil fuel for electricity production. Contribution, scenarios, and sensitivity analyses highlighted the importance of utilizing green energy sources, along with efficient transportation and substrate drying technologies. The study also highlighted the need for further research to optimize the inclusion rate of the valorized product in poultry feeds, and better resolved regional, infrastructural, and logistical contexts.