Rainwater Harvesting System (RWHS) can play a multipurpose role, contributing to the management of rainwater runoff, in addition to the water supply. This article assessed the potential reduction in stormwater runoff by adopting small-scale RWHS in the Brazilian semiarid region based on the Curve-Number (CN). RWHS could minimize runoff in frequency and volume, leading the built environment to perform closer to the land’s natural conditions. Before urbanization, the region had a CN of 76. In post urbanization, a case study of multiple houses showed that the adoption of RWHS could reduce the CN from 86 to 80. A reasonable design (0.5 demand fraction and 2000 L tank capacity) could minimize runoff volume by 34% and frequency of occurrence by 66%. Even RWHS with a minimal design, i.e. small tank capacity and low demand, might contribute to the safety of people, resilience, and sustainability of the city’s infrastructure.

Masonry wall is a key construction subsystem, but it embodies significant environmental and energy burdens within the life cycle of buildings. Soil-cement bricks and blocks stand as an alternative low-cost masonry material, but despite the widespread claim to be environmentally friendly, more systematic investigation is lacking. This study aimed to assess the life cycle environmental and energy performance of 1.0 m² of a soil-cement brick masonry wall from cradle-to-construction in terms of carbon, energy, and water footprints, and fossil and mineral resource use, as well as compare it with conventional technologies such as ceramic and concrete block masonries in Brazil. Results showed that raw materials are a major contribution to soil cement masonry walls, followed by the joints and links with columns, in which cement stands out among other inputs. Hydraulic pressing in brick production had a negligible burden increase compared with manual pressing. The PVA mortar joint outperformed the PVA glue one, whereas resin coating performed better than cement mortar. In comparison with ceramic and concrete masonry walls, the soil cement masonry presented overall better environmental and energy performance and was the least affected by the inclusion of finishing coating layers and transport of materials in the sensitivity analysis scenarios, although improved scenarios of conventional options could be competitive, e.g., ceramic masonry with blocks produced by firing reforested wood for the carbon footprint. Scale-up analysis revealed that widespread deployment of soil cement masonry in the built environment would substantially avoid environmental and energy burdens compared with conventional technologies.

RESUMO O objetivo do trabalho foi avaliar a operação e manutenção de um sistema de esgotamento sanitário centralizado, composto de três subsistemas, que atende 367 mil habitantes no Nordeste do Brasil. A avaliação do ciclo de vida considerou um inventário amplo de operação e manutenção do sistema de esgotamento sanitário com as redes de coleta, estações de tratamento de esgoto, disposição do esgoto tratado no corpo hídrico e gestão do lodo. O arranjo tecnológico das estações de tratamento de esgoto avaliadas incluiu o reator do tipo upflow anaerobic sludge blanket, seguido de lagoa aerada e lagoa de polimento em um subsistema, e upflow anaerobic sludge blanket seguido de reator de lodo ativado por aeração prolongada em dois subsistemas. O desempenho energético utilizou o método de demanda de energia acumulada e a pegada de carbono empregou o método de potencial de aquecimento global de 100 anos do Painel Intergovernamental sobre Mudanças Climáticas. O sistema de esgotamento sanitário avaliado demandou 5,12 MJ·m−3 e emitiu 4,08 kg CO2eq·m−3. As maiores contribuições do sistema de esgotamento sanitário avaliado foram a eletricidade, com 62% da demanda energética, e as emissões diretas para o ar, com 94% da pegada de carbono, sendo as emissões dos reatores upflow anaerobic sludge blanket com 76% da pegada de carbono. A identificação dos aspectos e impactos ambientais do sistema de esgotamento sanitário avaliado apoia a inovação tecnológica e gerencial para otimizar o desempenho energético e mitigar as emissões de gases de efeito estufa.