Sustainability assessment of the valorization scheme of used cooking oils (UCOs): the case study of Bogotá, Colombia

Abstract

AbstractHarnessing of second-generation feedstocks via circular economy approaches is generally considered as environmentally friendly. Nonetheless, different potential impacts can be caused during collection and transformation of such feedstocks, affecting overall sustainability. Assessment of such impacts is of particular importance when producing waste-based biofuels. In this regard, this work’s aim was to carry out a sustainability assessment of the existing reclaiming and exploitation strategy of used cooking oil (UCO) in Bogota, Colombia. Currently, UCO is collected, pretreated, and mostly exported to Europe for biodiesel production. Based upon literature data and a life cycle assessment (LCA), several sustainability criteria were derived, measured, and interpreted within the framework of the integrative concept of sustainability (ICoS). As a reference system, results were compared with those obtained from assessing current production of first-generation palm-oil-based biodiesel. Results from LCA indicate that, per ton of UCO-based biodiesel, emissions of 1.06 kg PM2.5-eq, 2.54 kg NOx-eq, 607.6 kg CO2-eq, 2.81 kg SO2-eq, and 0.09 kg P-eq are generated and that there is use of 9.1 m3 water, and 259 kg oil-eq. UCO transportation and biodiesel production stages were the larger contributors to such impacts, and surprisingly, equivalent emissions of CO2 and fossil fuel consumption were higher than those of first-generation biodiesel. Nevertheless, UCO valorization displayed a better overall performance with respect to the reference system in terms of health, safety, environmental, economic, and social indicators. All impacts were reduced by 30 to 50% under a scenario of local production and consumption of biodiesel.