A reduction in global impacts through a waste-wastewater-energy nexus: A life cycle assessment

This work presents the results of a comparison of three different management scenarios (one current and two future) of waste, wastewater, and their related energy systems in Southern European regions. A Life Cycle Assessment (LCA) has been applied to all the different steps of the complex scenarios in order to provide a more holistic, robust, and scientific approach that is able to highlight the beneficial effects of the integration of different plants (Waste to Energy - WtE, Anaerobic digestion - AD, wastewater treatment plant - WWTP) included in a symbiotic nexus. The LCA results have shown that an important reduction in the impact of Municipal Solid Waste (MSW) management is obtained from the recovery of separately collected materials, but there is still a large gap that could be filled by the introduction of energy recovery (by means of AD and WtE) and through its symbiotic use to support the anaerobic digestion, wastewater reuse, and sludge recovery processes. The proposed approach, which is based on a waste-wastewater-energy nexus and industrial symbiosis, could be adopted to support these regions to significantly increase circularity and fill the gap, thus favoring a significant rapprochement in the path toward the New Green Deal promoted by the European Union.