A modelling testbed to demonstrate the circular economy of water

Abstract

Climate change poses significant challenges in terms of water scarcity, environmental crisis, and economic uncertainty. This situation drives an increasing need to pursue more sustainable futures and to conserve and maximise the use of resources whenever possible. The EU-funded H2020 NextGen project aimed to boost sustainability using new and novel technologies and approaches implemented within the water cycle, and to maximise the efficient use of water and water-embedded resources. To facilitate and communicate the potential benefits of such technologies, NextGen developed Serious Games (SGs), enabled by underlying System Dynamic Models (SDMs), for demonstrating how interactions between water, energy, and materials/embedded resources within the urban water cycle can be utilised in the context of the Circular Economy of water. As part of a fast-track development process, a testbed dubbed “Toy Town” was developed that encompasses a range of technologies and options that provides a demonstrable framework that can later be refined and modified accordingly for other case studies. The underlying SDM driving the SG is built using the Julia programming language. The testbed incorporates a range of components, including water-saving and water-reuse technologies, stormwater management, and wastewater treatment systems. The SDM acts fundamentally as a mass-balance model tracking over time volumetric flows of water/wastewater and the concentrations/dilution of pollutants/material within the urban water cycle. A variety of water use, water reuse and wastewater treatment components can be tested within this model to maximise the resource potential of the water and material moving through the cycle. The paper focuses on an extreme drought scenario and highlights the benefits of a modelling testbed for exploring potential technological solutions for managing the urban water cycle and how such solutions can be employed in the context of the circular economy of water. The NextGen SG thus has the potential to improve stakeholders’ understanding of the implementation of novel technologies in the water cycle and the benefits that could be accrued by such stakeholder groups.