Water is fundamental to our existence and has increasingly been put under pressure by soaring population growth, urbanization, agricultural farming and climate change; all, of which impact the quantity and quality of our water resources. Water utilities (WUs) are challenged to provide clean, safe drinking water when faced with aging, costly infrastructure, a price of water that is not reflective of its true value and the need for infrastructure to remain resilient in a time when threats of floods and droughts are pervasive. In the linear take-use-discharge approach, wastewater is treated only to be returned to waterways and extracted again for treatment before drinking. This can no longer sustain our water resources as it is costly, energy-intensive and environmentally unsound. Circular economy (CE) has been gaining attention in the water industry to tackle this. It follows the 6Rs strategy of reduce, reuse, recycle, reclaim, recover and restore to keep water in circulation for longer and reduce the burden on natural systems. The aim of this study is to determine what the economic and operational system effects of CE are on WUs, informing them of CE’s potential to change their business operations and business model while highlighting its associated challenges. Based on a review of literature, input from expert interviews (Q4 2019) and case studies, an economic view of the urban water system is qualitatively modeled, on top, of which a circular water economy system is designed using a causal loop-diagramming system mapping tool. Digitalization, water reuse and resource recovery were determined to underpin circularity in water, providing operational benefits through efficiencies and diversification of revenue streams. However, issues of investment and a missing enabling legal framework are slowing the rate of uptake. On this basis, CE represents both a challenge and an opportunity for the water industry.
Sewer Mining as a Distributed Intervention for Water-Energy-Materials in the Circular Economy Suitable for Dense Urban Environments: A Real World Demonstration in the City of Athens
