Lin Y.-ISHU-YUAN PAN2022-04-252022-04-25202104921550https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120317646&doi=10.6937%2fTWC.202106%2fPP_69%282%29.0001&partnerID=40&md5=1b100fc7617aea04fc030516739964bahttps://scholars.lib.ntu.edu.tw/handle/123456789/605832To explore more available water sources, reclamation of non-conventional wastewater for non-potable purposes in agricultural, industrial or domestic uses has attracted significant attention. For the security and safety of sustainable water services, in this Perspective, we first define the so-called concept of “green circularity”, which considers four essential criteria: high energy-water efficiencies, low costs, use of renewables, and without secondary pollution. Then, we suggest four priority research directions for the future water reclamation systems, including (1) establishment of decentralized water supply framework, (2) incorporation with green chemistry principles, (3) deployment of fit-for-purpose water technologies, and (4) balance of water and energy efficiencies for system optimization. This Perspective should provide an insight into sustainable water services, especially for reclamation of non-conventional water as new water sources. ? 2021DecentralizationElectrochemical TechnologiesFit-for-PurposeGreen Chemistry PrinciplesWater-Energy NexusEnergy efficiencyPotable waterWastewater reclamationWater conservationWater pollutionWater supplyChemistry principlesDecentralisationElectrochemical technologyFit for purposeGreen chemistry principleGreen-chemistrySustainable waterWater energyWater sourceWater-energy nexusSustainable chemistrydecentralizationelectrochemical methodsustainabilitywater economicswater managementwater resource[SDGs]SDG6[SDGs]SDG7[SDGs]SDG9journal article10.6937/TWC.202106/PP_69(2).00012-s2.0-85120317646