Reduction of potable water consumption and sewage generation on a city scale: A case study in Brazil

Abstract

This article aims to estimate the reduction of potable water consumption and sewage generation in the city of Joinville, southern Brazil. Four strategies were considered to promote potable water savings: replacement of conventional toilets with dual-flush ones, greywater reuse, rainwater harvesting, and the combination of these three strategies. Residential, public, and commercial sectors were assessed. The potential for potable water savings ranged from 1.7% to 50.5%, and the potential for sewage generation reduction ranged from 2.1% to 52.1%. The single-family residential sector was the most representative for water savings and sewage generation reduction. The public sector would be the least contributor to such reductions. It was found that in the city of Joinville, for low non-potable water demands, greywater reuse was the most viable strategy to save water. When non-potable demand is high and there is a large catchment area, it is recommended to install rainwater harvesting systems. It was concluded that there is a high potential for potable water savings and reduction of sewage generation if measures were adopted in Joinville, but it is necessary to evaluate which strategy is the most appropriate for each building.