The Circular Economy of Water - Developing a Strategy to Transition to a Water Smart Society

Many countries have implemented universal metering, increased water tariffs, delivered comprehensive demand management campaigns and reduced mains water network leakage rates. The next frontier in innovation is implementing a Circular Economy of Water (CEW). This is where used water is reused (without treatment), recycled (with treatment) and/or valuable products embedded within the used water stream are recovered and reused within different processes. Understanding the potential to supplement mains water with fit for purpose water is critical to implementing a CEW. However, there are limited studies which quantify micro component household water use in Ireland and Europe. This study sets out to address this gap in knowledge. The results presented in the paper show that for every 100 L of potable mains water supplied daily, 28 L was flushed down the toilet, 22 L was used in the hot water system, 17 L was supplied to cold water taps for personal hygiene uses and 33 L was used in the kitchen.  By proving that water supplied is utilised by different micro-components of a domestic household and through quantifying the amount consumed by each micro-component, the author justifies the concept of fit for purpose water, where function governs quality. The authors propose a Circular Economy of Water hierarchy focused on Reduce, Reuse, Recycle and Recover. A detailed twelve-step strategy is suggested to facilitate this transition to a water smart society.