Potential use of rainwater and reclaimed water in residential buildings

Abstract

ABSTRACT: This paper presents the results of a study conducted in Portugal and Brazil about rainwater and reused water potential use inside buildings. The study was based on field surveys conducted in both countries where water consumptions measurements were performed in some houses with purpose to identifying the parcels that make up water consumption requested by the use of domestic appliances for attendance of its users. A water use tendency is presented considering a scarcity scenario and consumption “per capita” in both countries as an aid to understanding the importance of the theme for water resources preservation. It is shown researches results carried out in Brazil and Portugal where a collection of internal water use for domestic purposes inside buildings are presented and defined as a set of actions for reducing of water consumption and especially dedicated to carrying out a calculation of the potential use of rainwater in buildings (particular for toilets). Considering the residential water profiles it was identified which part could be supplied by rainwater and the essential part exclusively supplied with drinking water. From this perspective was performed some calculations to find out the water savings by using rainwater for domestic purposes and which appliances inside buildings are eligible to be supplied. As complementary and considering that waste water generated by some appliances (showers) it was performed the calculations including the wastewater reclaimed inside buildings. The study finds out an average of drinkable water savings of 28 to 100 % for WC cisterns using rainwater and reclaimed water. Some other savings are presented according to sanitary appliance and inside or outside house activities when rain and reclaimed water were used.