Life Cycle Assessment of a Circular Economy Process for Tray Production via Water-Based Upcycling of Vegetable Waste

Abstract

With one-third of food being wasted at the various steps of the value chain, there is a large amount of biomass constantly being discarded, also wasting the resources consumed for its production. Several strategies have been proposed to use this biomass as a source of raw materials for the production of plastic alternatives, but the environmental impact parameters have rarely been estimated to understand if the proposed process provides an overall benefit. The purpose of this paper is to analyze, through an experimental laboratory campaign, the production process of a vegetable biocomposite material obtained by valorization of biomass from two sources: unsold vegetables from a wholesale market and carrot pomace obtained as a byproduct of juicing. The obtained biocomposite films were thermoformed into trays to replace the traditional plastic food containers made principally with PET. Different scenarios for the lab-scale production of trays were evaluated by testing two water-based processing methods for the two types of biomass used. In order to understand which of the four scenarios was the least impactful, the global warming potential, the cumulative energy demand, and the water scarcity index were used as indicators. Among the different lab-scale processing scenarios for the upscaling of vegetable waste, the least impactful was starting from the unsold/discarded vegetables collected at the wholesale market that were processed via water-based hydrolysis catalyzed by formic acid. Impact parameters were comparable or better than two traditional polymers (PET and HDPE) and two biopolymers (PLA and biopolymer from starch), showing that this process has excellent potential, from an environmental point of view, of substituting plastic packaging.