Sistema integrado de reciclagem de águas pluviais e cinzas para adaptação às mudanças climáticas

Abstract

Urban areas face increasing challenges related to water supply, which are exacerbated by the impacts of climate change and continuous population growth. In this context, integrated approaches that combine Rainwater Harvesting (RWH) and Greywater Reuse (GWR) have emerged as promising alternatives to enhance urban water resilience and promote more sustainable water resource management. Against this backdrop, this thesis aims to contribute to the advancement of knowledge and to the improvement of practices related to the design, operation, and evaluation of decentralized and integrated RWH and GWR systems in residential settings, with a focus on financial, environmental, and operational aspects. To achieve this goal, three specific objectives were established: (i) to conduct a systematic literature review to identify design methods, knowledge gaps, and research trends related to these systems; (ii) to monitor the performance of an integrated RWH and GWR system operating in a residential building in Rio Verde, Goiás, Brazil, evaluating the quality and quantity of the water produced, the savings in potable water consumption, and the required maintenance frequency; and (iii) to assess the cost-benefit ratio of such systems at the household scale, considering environmental impacts through Life Cycle Assessment (LCA) and economic feasibility based on cost indicators. The results demonstrated that the complementary aeration and ultraviolet (UV) disinfection technologies implemented in the system were effective in removing organic matter, eliminating odors, and inactivating thermotolerant coliforms, ensuring satisfactory water quality for non-potable uses. Monitoring showed up to a 41% reduction in potable water consumption, highlighting the system’s potential to alleviate pressure on conventional water resources. The life cycle assessment indicated significant improvements in environmental performance, particularly when renewable (photovoltaic) energy was used to operate treatment and pumping devices. Moreover, the economic feasibility analysis showed that the system becomes financially more advantageous under scenarios of higher demand and intensive use of the recycled water, underscoring the importance of proper system sizing and user awareness. In conclusion, residential integrated RWH and GWR systems are technically feasible, environmentally beneficial, and economically attractive in urban contexts, representing a promising strategy to enhance water resilience and foster more sustainable urban water management practices. It is further recommended that public policies encourage the adoption of such solutions through subsidies, specific regulations, and environmental education programs, thereby maximizing their large-scale benefits.