The Ultimate Water Plant

The Ultimate Water Plant is a collaborative project involving parties in the water sector who want to demonstrate how, and subject to which conditions, treated sewage can be made available as a supplementary source of drinking water. KWR is participating as a knowledge partner on behalf of BTO-WiCE, primarily for the Social and Institutional Acceptance, and Water System Impact, components. In addition, KWR will work on Knowledge Access and connections with the drinking water utilities (via WiCE).

Drinking water sources under pressure

Drinking water demand in the Netherlands will rise sharply between now and 2050 as a result of water shortages, population growth, economic growth and increased per capita use. For some years, water utilities have been seeing how current extraction capacity is inadequate to continue supplying adequate amounts of drinking water everywhere in the future. That capacity therefore needs to be expanded, and new and additional sources of drinking water are needed. Increasingly, space is a limiting factor in the search for new extraction locations. Other developments such as the energy transition, large-scale housing development, problems with nitrogen emissions, and climate adaptation all require space as well. This means that new locations where water can be extracted for drinking water are scarce.

One of the new sources of drinking water could be treated wastewater (effluent from wastewater treatment plants). The Netherlands does not have any experience with treated wastewater as a source of drinking water. Other countries affected by water scarcity do have experience in this area, and they are increasingly producing drinking water from wastewater. So it is technically feasible. The question arises of whether treated wastewater can also be an accepted and suitable source in the Dutch context.

Our role in the Ultimate Water Plant

To answer that question, water utilities and water authorities are working together in the Ultimate Water Plant to demonstrate how, and subject to which conditions, treated wastewater could be used directly as an additional source of drinking water.

A consortium of some twenty organisations took the first step in 2021. Together, we have identified the principal issues. From 2023 onwards, we will be addressing those issues by taking concrete steps at three levels: local, regional and national.

  • At the local level, we will be working in a joint demonstration plant to show that it is possible to produce high-quality drinking water from treated wastewater safely and continuously. The monitoring required for the approval of treated wastewater as an additional source of drinking water will take place in consultation with the competent authorities.
  • At the regional level, we will be going through the transition issues in about five regions in the Netherlands, each with different characteristics. During the process, we draw on a concrete case and real-life data. Before that, we will engage in discussions with all the regional organisations in question about the effects on the water system, the relationship between this source and other sources, acceptance and perception, costs, benefits and value, governance and so on. These activities will be organised in regional labs.
  • The national level is where all the results will come together. We will group all the outcomes and lessons learned from the local and regional labs and draw generic conclusions from them. We will bring the issues that require a national approach to the attention of the relevant platforms of, for example, the national government and sector organisations.

Social and institutional acceptance

Although water awareness in the Netherlands is low, customer satisfaction with the water sector is high. The biggest obstacle to reusing water for drinking water is a perceived lack of public, and institutional, acceptance. KWR will take the lead in conducting a public acceptance survey and stakeholders in the regional labs will engage in discussions with stakeholders such as government authorities, drinking water utilities, customer panels and other users to explain and discuss the use of treated wastewater as a potential source of drinking water. Measurements made at the outset and completion of the project will show the extent to which thinking and feelings about this topic develop over the course of the project.

Water system impact

The use of treated wastewater as a source of drinking water affects the entire water system, particularly as a result of the partial removal of effluent from surface water. Local characteristics determine the extent to which this has an effect and whether it is positive or negative. From the perspective of the water system and land use, classifications or ‘profiles’ can be sketched of suitable or less suitable areas for the use of treated wastewater as a source of drinking water. What are the effects on the water system and the use of space resulting from the use of treated wastewater to produce drinking water? What are the location-specific characteristics in this respect in the Netherlands? How does this compare with other sources? Thinking in terms of water systems is central here. These themes are being developed in the regional labs.

This infographic shows the pathway from wastewater to drinking water and what we need to look out for.