Aproveitamento de águas pluviais e o reúso de águas cinzas em edifícios residenciais de Brasília ”“ parte 2: viabilidade técnica e econômica

Abstract

The feasibility of implementing rainwater harvesting (RWH) and greywater reuse (GWR) systems on residential multi-storey buildings is analysed and results are presented in two articles. The first part characterizes domestic water end-use consumption for typical residential building typology found in Brasilia, Brazil, and identifies potential water savings promoted by different RWH and GWR systems. The second part pinpoints possible solutions to adapt the existing residential building stock in Brasilia and carries out a financial assessment of the cost-benefits for different types of RWH and GWR systems. Overall, findings suggest that building adaptation for rainwater use in outdoor demands is a simple and cost-effective solution. In some cases, ground level or basement mains water storage tanks can be retrofitted to serve as rainwater cisterns, reducing capital costs. Building adaptation for rainwater use in indoor demands proved to be an unfeasible solution due to high refurbishment costs. On the other hand, indoor greywater reuse systems promote significant financial benefits, outweighing refurbishment costs. Outdoor greywater reuse proved to be an unfeasible option due to high system costs and low financial benefits.