| Abstract |
Humanity has been overexploiting essential resources such as water, energy, and nutrients. Hence, the recovery of the said resources in Urban Water Systems (UWSs) has become not only advisable but a necessity. In this context, the circular economy is an approach that focuses on regenerating natural capital, closing resource loops, and decreasing the amount of waste discharged into the environment. While some works are available accounting for wastewater reclamation, few papers also evaluate the recovery of biosolids and energy. This research aims to analyze the environmental and economic sustainability of UWS, considering circular economy strategies through resource recovery. Also, this study aims to identify the main processes impacting the life cycle of UWS and whether sustainability is enhanced in the resource recovery alternatives. The Life Cycle Assessment (LCA) and the Life Cycle Costing (LCC) methods were applied to five alternatives of UWS considering a conventional scenario, as well water, energy, and biosolids recovery alternatives. In the end, a water-energy-nutrients nexus scenario is analyzed. The study uses four LCA methodologies: (1) IPCC 2013 for the Global Warming Potential (GWP) category, (2) Cumulative Energy Demand (CED) for the energy input evaluation, (3) ReCiPe Endpoint (H/H) V1.13/ World, and (4) aware, to estimate water footprint. Results show that the environmental impacts estimated by the IPCC, AWARE, and CED are similar to the considered alternatives. Furthermore, the LCC was conducted using the net present value method. The results highlight that the energy recovery scenario shows the best environmental performance, while the water-energy-nutrient nexus UWS has the best economic performance. In the final aggregation, the biosolids recovery had a better sustainability performance. It is important to highlight, however, that the best sustainable option will vary depending on the location and system type. |