Alternative water resources for industry : Designing environmentally compatible regional supply networks

Abstract

Industry contributes 20% to the total water use of humanity (Boretti and Rosa, 2019; United Nations World Water Assessment Programme (WWAP), 2014).Manufacturing accounts for 25% of the total industrial water use and energy production for 75% (United Nations World Water Assessment Programme (WWAP), 2014). The water demand of industry will continue to increase as countries become more industrialized and the need for manufactured goods continues to grow. The total water demand of the manufacturing industry alone is expected to increase by 400% globally in 2050 (Boretti and Rosa, 2019; Wada et al., 2016). Changing the way industry is supplied with water is needed to avoid overexploitation of the available renewable water resources.The interconnected nature of the hydrological cycle implies that the concept of sustainable yield is not only applicable to aquifers but to any water system.Environmentally compatible water use expands the concept of sustainable yield to include all the interactions between the water user and the (local) water system.Environmentally compatible water use not only considers the effects of water extractions but also considers the amount of (waste)water that can safely be including rainwater, wastewater, stormwater, treated wastewater, and brackish (ground)water to cover the demand of the user. Using a wide variety of alternative sources makes it possible to provide water based on the 'fit-for-purpose' concept (Sharma et al., 2013). Fit-for-purpose entails delivering water according to the required specifications of the user. The possibility to deliver water with a specific quality is especially relevant for industry since not all industrial processes require the same water quality . The benefit of delivering water at the desired quality is that unnecessary treatment costs can be avoided (Capodaglio, 2021). Besides the possibility to deliver 'fit-for-purpose' water, decentralized systems are more flexible and can be adapted to the local needs and opportunities more easily than centralized systems . 14 sizing and planning of rainwater harvesting systems can yield significant water savings in urban areas Zhang et al., 2019) but is not yet widely applied in industry.Using a wide range of alternative water resources in decentralized water supply systems means that the supply and demand of water needs to be connected spatially and temporally. The challenges that this can bring are explained in the next section. B Spatial and temporal challenges of water supply systemsWater supply systems make it possible to overcome the disconnect between the demand and supply of water resources in space and time. In addition, water quantity and water quality must be considered simultaneously when connecting supply with demand with decentralized water supply systems. For decentralized water supply systems to be effective the selection of an appropriate scalespatially and temporally -is important (Arora et al., 2015). In this section the spatial and temporal challenges for water supply systems are highlighted. 1 ...