Environmental Policies

Assessment of alternative water supply options

Client: DG Environment • European Commission

Other Partners: Flemish Institute for Technological Research NV (VITO) in cooperation with: Ecologic (Austria) – ACTeon (France) – I.A.CO (Cyprus) – TAU Consultora Ambiental (Spain)

The main objectives of this project were to:

  • Assess the risks and impacts of four alternative water supply options (desalination, wastewater re-use, ground water recharge, and rainwater harvesting); Provide an overview of social, economic and environmental risks and impacts of the four alternative water supply options.
  • Assess the extent to which the possible negative effects from these water supply options in terms of environment and human health can be mitigated; On the basis of 14 cases studies, the most appropriate mitigation measures that resolve the adverse impacts associated with the four alternative water supply options were identified and their technical and financial feasibility was assessed.
  • Identify conditions for the sustainable development of alternative supply options on the basis of five case studies across Europe: the role of desalination and wastewater re-use to resolve chronic water shortages in Cyprus; a mix of solutions to resolve chronic water shortages in Malta; the role of the AGUA Desalination Project as an alternative to the inter basin water transfer over long distances in Southern Spain; waste water re-use for the industry and drinking water supply as an alternative to groundwater and the water transfer over short distances in Belgium, and rainwater harvesting with regards to improving the management of urban storm runoff and at the same time enhancing the quality of groundwater aquifers that supply water to the city in Berlin Germany.

Main findings and conclusions of the study were:

  • Desalination is growing in importance, but its supply regime is rigid and inflexible as per its design specifications. There are particular environmental and economic concerns, such as high energy use, and disposal of brine.
  • Wastewater re-use is a proven alternative water supply technology, with relatively low capital costs and energy use, reducing the demands for freshwater for non-potable uses. Concerns for strict quality controls.
  • There is not much information on the technology uptake of rainwater harvesting. It replaces mainly potable water supply within the house or industrial plant for non-potable purposes. Investment cost and retrofitting, and rainfall distribution affect uptake of Rainwater Harvesting.
  • Groundwater recharge includes tertiary treated waste water or primary treated surface or rain water. Strict controls to ensure that the wastewater is sufficiently purified, thus reliable mitigation measures and procedures have to be more or less guaranteed.
  • The main conclusion from the five case studies is that alternative water supply options can be successfully used to solve water management problems, both related to droughts, storm water management and water quality issues.
  • The requirements of the WFD to implement integrated water management and cost recovery programmes will contribute to a better appreciation of the benefits of alternative supply options. However, ready to use tools and data are missing to facilitate the analysis of local problems and account for the full costs and benefits of all options.
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