Life Cycle Assessment from food to food: A case study of circular economy from cruise ships to aquaculture

Industrial symbiosis principles, reprized in industrial ecology definition, are recently embraced by circular economy concept as the basis for characterization of cradle-to-cradle approach, with particular interest on global markets with growing environmental issues such as food sector. This paper investigates a potential innovative pattern of recycling food waste from cruise ships for use as feed in aquaculture, in terms of environmental sustainability. Comparative Life Cycle Assessment is used to evaluate the possible potential benefits of replacing conventional formulations of feed mix for salmon with food waste, generated and processed onboard a vessel where turbo-drying technology has been tested as a case study. A set of three indices, otherwise possible stand-alone indicators, is selected to measure global warming potential, non-renewable cumulative energy demand, and water scarcity index. The basis for comparison is represented by a typical commercial feed product for aquaculture in Norway and UK. A conventional feed formulation shows higher life cycle burdens for the whole set of indicators, with respect to the analysed case study. In particular, traditional feed product in UK shows the worst performance in terms of carbon footprint and non-renewable energy demand, whilst the Norwegian traditional mix is source of the highest impact for water scarcity. The investigation of supply chains results particularly relevant for highlighting that bottle-necks are not univocal for the different impact categories. For instance, when conventional mix in Norway is analysed from a water footprint perspective, crop-derived products result to be more influent than fish-derived ones, unlike for carbon and energy indicators.