title: Holistic assessment of a secondary water supply for a new development in Copenhagen, Denmark.
abstract: Increasing stress on water resources is driving urban water utilities to establish new concepts for water supply. This paper presents the consequences of proposed alternative water supply options using a unique combination of quantitative and qualitative methods from different research fields. A former industrial harbor area in Copenhagen, Denmark, is currently under development and all infrastructure will be updated to accommodate 40,000 inhabitants and 40,000 jobs in the future. To reduce stress on water resources it has been proposed to establish a secondary water supply in the area as an alternative to the conventional groundwater-based drinking water supply. Four alternative concepts for a secondary water supply have been considered: 1) slightly polluted groundwater for use in toilets and laundry, 2) desalinated brackish water for use in toilets, laundry, and dishwashers, 3) desalinated brackish water for all uses, including drinking water, and 4) local reclamation of rain and gray water for use in toilets and laundry. The concepts have been evaluated for their technical feasibility, economy, health risks, and public acceptance, while the concepts' environmental sustainability has been assessed using lifecycle assessment and freshwater use impact methods. The holistic assessment method exposes conflicting preference solutions depending on assessment criteria, and reveals multi-faceted consequences for choices in urban water management. Not one concept turns out unambiguously positive based on the evaluation criteria included here, but the systematic evaluation will leave decision-makers informed on the consequences of their choices.
authors.affiliation: Technical University of Denmark, Department of Environmental Engineering, Miljoevej 113, DK-2800 Kgs. Lyngby, Denmark. Electronic address: mryg@env.dtu.dk.
authors.forename: M
authors.initials: M
authors.lastname: Rygaard
authors.affiliation: HOFOR, Ørestads Boulevard 35, DK-2300 København S, Denmark. Electronic address: bego@hofor.dk.
authors.forename: B
authors.initials: B
authors.lastname: Godskesen
authors.affiliation: DHI, Agern Alle 5, 2970 Hørsholm, Denmark. Electronic address: clj@dhigroup.com.
authors.forename: C
authors.initials: C
authors.lastname: Jørgensen
authors.affiliation: Aalborg University, Department of Development and Planning, A.C. Meyers Vænge 15, 2450 København SV, Denmark. Electronic address: bhof@plan.aau.dk.
authors.forename: B
authors.initials: B
authors.lastname: Hoffmann
mesh_terms: D003247:Conservation of Natural Resources / Q000379:methods*; D003718:Denmark; D006798:Housing; D006801:Humans; D062066:Water Resources / Q000592:standards / Q000706:statistics & numerical data*; D014881:Water Supply / Q000592:standards / Q000706:statistics & numerical data*
keywords: Freshwater impact; Health risk; Lifecycle assessment; Water reuse; Water supply; user perspectives