Aproveitamento de águas pluviais e o reúso de águas cinzas em edifícios residenciais de Brasília ”“ parte 1: reduções no consumo de água

Abstract

Rainwater harvesting (RWH) and greywater reuse (GWR) systems are decentralized water management strategies capable of promoting reductions in urban water demand. However, little is known about their feasibility at the building scale for strategic planning. In order to evaluate the feasibility of such water systems in residential multi-storey buildings, it is crucial to understand disaggregated domestic water uses to estimate potential water savings and verify the applicability, costs and benefits for building adaptation. This article focuses on the characterization of domestic water end-uses for multi-storey residential building stock from Brasilia, Brazil, and on the identification of potential water savings for different RWH and GWR systems. Overall, results demonstrate high indoor water end-uses on shower heads (23.0%), washing machines (21.4%) and toilet flushing (15.3%). Outdoor water end-uses represent a small fraction of total building consumption (3.5%). Findings indicate that average roof areas are capable of supplying rainwater for 48% of laundry demands, 60% of toilet demands and 100% of floor washing and irrigation demands. Higher water savings can be achieved with greywater reuse in indoor demands such as clothes washing (2,541 m³/yr) and toilet flushing (1,815 m³/yr). Both RWH and GWR systems are capable of promoting savings equivalent to 811 m³/yr.