Concept Mapping of Food Waste Management Alternatives within the Food-Energy-Water Nexus

There are currently many knowledge gaps related to the role of food waste within the food-energy-water (FEW) nexus. Wasted food is a high-magnitude, energy- and nutrient-rich waste stream. Energy and water are consumed or contaminated both during production of wasted food and management of disposed food. Further, carbon and nutrients from landfilled food are potentially persistent and problematic contaminants that require intensive energy to treat, and/or large volumes of water to assimilate. Better understanding of potential water and energy costs underlying various alternative food waste treatments are necessary, for example, to inform decision making as communities implement ‘zero waste’ or the USEPA/USDA goal to halve food waste by 2030.Our approach towards FEW research is integrated through the energy and water footprints of wasted food, with particular attention to the uncharted and highly coupled water and energy impacts of food waste management.Herein, we present an approach to compare costs through the integrated FEW system related to several alternative pathways for food waste in the post-consumer phase. We consider food waste disposed in landfills, incinerated, digested for energy production, or composted. Our methods encompasses a conceptual methodology for characterizing interrelated water and energy impacts related to various alternative treatments for wasted food, evaluating potential magnitudes and directions of energy, water and nutrient transfer related to food waste, and feedbacks of human behavior. Through this approach, gaps in fundamental knowledge related to energy and water impacts of food waste are clearly identified.