Environmental impact of food waste bioconversion by insects: Application of Life Cycle Assessment to process using Hermetia illucens

Abstract

Food waste management strategies are mainly focused on waste minimization, but the search for new solutions to waste valorization is also a viable and potentially advantageous alternative. In this context, the aim of this study is to assess the potential environmental impacts of food-waste bioconversion into compost and dried larvae through the action of Hermetia illucens, by applying Life Cycle Assessment (LCA). In international scientific literature, there are many studies concerning the utilization of insects for food-waste bioconversion, but very few articles relate to the application of LCA in this sector and none of these refers to Hermetia illucens. Furthermore, the process of bioconversion through Hermetia illucens is a very attractive option, considering that it represents a potential valuable solution to two problems: food waste management on the one hand and, on the other, the rising global demand for feed (dried larvae can be used in aquaculture feed production) or the competition between land use for energy crops and for food crops (dried larvae are a fat-rich resource potentially usable for the production of biodiesel). In particular, the LCA results presented in this study refer to the assessment of the potential environmental impacts of a pilot plant in which H. illucens is employed for food-waste treatment. From 10 tonnes of food-waste input, 300 kg of dried larvae and 3,346 kg of compost are produced. Three different functional units were used to carry out the analysis: the input of the production process, therefore 1) food-waste; the output composed of dried larvae, for which 2) the protein content (fundamental characteristic for using this product in aquaculture) and 3) the lipid content (to be used for biodiesel production) are considered. Results related to the functional unit of 1 tonne of food waste treated show a value of 30.2 kg CO2 eq in terms of Global Warming Potential, 215.3 MJ in terms of Energy Use, and 0.661 m2a in terms of Land Use. When compared with alternative sources of raw material for feed or biodiesel, these results show that the most significant benefits of insect production are connected to Land Use, while Energy Use is the main burden, and the estimation of Global Warming Potential is still affected by many uncertainties.