Meaning of circularity for the water sector

Let’s begin by defining circularity. Because, even if it seems straightforward, it has some tricky aspects. Bert van der Wal, head of water technology at Evides and professor at Wageningen University, starts with the basics. ‘Water is by nature circular. Just think of the hydrologic cycle. Water is never lost. So if you then talk about water in the circular economy, you mean that you don’t want to discharge the water. Wastewater is still valuable: it is a source of freshwater. You can reuse the water in multiple applications and you can also recover the resources contained in it.’

Broad view of circularity

Colleague Pim van Thiel, sustainability and innovation adviser at Evides, adds: ‘Our focus on circularity is directed at the primary process: the reuse of water and resources. Instead of generating waste products we want to deliver high-value residuals that can be used again. But circularity is much broader than that. We can also procure circularly, build circularly, and manage all of our assets circularly. And of course, circularity is not an objective in itself. It is a means of achieving objectives like reducing greenhouse gas emissions or addressing the loss of biodiversity. You have to see circularity as part of an entire system and approach it accordingly.’

Residual product from drinking water

Aalke Lida de Jong, environmental and sustainability manager at AquaMinerals, also expresses her view of circularity in her own terms. AquaMinerals markets for the drinking water utilities and some Water Authorities the residuals and resources recovered from their treatment processes. De Jong therefore works up-close with circularity on a daily basis. ‘When you look at it broadly, circularity overlaps with sustainability. So let me take a narrower view: for me circularity means the use of as few raw materials as possible, after which you return the residuals entirely to the biological and technological loops.’ In the case of calcite pellets for example this is already being done very successfully. Both Van der Wal and De Jong talk about the Cradle to Cradle certification which was recently attributed to this high-value residual product from drinking water production processes. ‘What is even greater is when you can remake a feedstock used in water treatment from the residuals that the treatment itself generates,’ says De Jong. ‘Then you’ve achieved a truly circular cycle. A good example is the seeding material used for softening, which is made from the calcite that is generated by this same process. We’re trying to develop more cycles of this type.’

Circular Water 2050

A further addition to the vision on circularity comes from Kees Roest, who works at KWR. As a researcher, his areas of activity include the water cycle of the future and how this fits in with a circular Netherlands. For the Circular Water 2050 project, which is part of the Water in the Circular Economy (WiCE) programme, Roest is participating in the development of an inventory of the raw materials used by the water sector in the production and distribution of drinking water and in wastewater treatment, and of the residual streams generated by these processes. ‘Circularity is more than the recovery and reuse of components,’ says Roest. ‘Ultimately, it is also about the environment and people. So circular developments cannot for example be at the expense of public health or societal wellbeing. This makes things pretty complex.’

Measuring circularity

An evaluation tool has been created within the Circular Water 2050 project to enable the measurement of all these factors related to circularity. This comprises 16 characteristics with which to evaluate concepts for their level of circularity (see illustration). The tool was derived from the model of the ‘Doughnut economy’, which scores economic prosperity, taking into account an ecological ceiling (the Earth’s capacity) and a social foundation. ‘The social foundation has to do for instance with public health, safety and wellbeing,’ explains Roest. ‘You can establish the system in the space between the foundation and the ceiling. We translated this framework’s characteristics into ones that are relevant to the water sector. This resulted in a dashboard on which you can check whether one concept is more circular than another. Of course, this is not the only way of measuring circularity; more and more monitoring tools are being created. This reflects a need at the practice level. I think this is a positive development which allows us to share experiences and knowledge.’

Dashboard for a circular water sector comprising 16 characteristics.

Challenges for the circular water cycle

With regard to these practice-related needs, Circular Water 2050 also resulted in another product: a visual future image of a circular water cycle, or the point on the horizon 2050 (see illustration). It is a representation of the creative ideas suggested during workshops with experts from the water cycle, as ways of bringing about increased circularity. ‘It’s a great tool to stimulate discussion,’ says Roest. De Jong was also involved in the elaboration of this visual brainstorming aid, since AquaMinerals is a project partner in Circular Water 2050, along with STOWA and the Energy and Resources Factory. ‘We think it’s important to have an image of the future,’ she says. ‘What does a circular water sector look like, and what still needs to happen for us to get there. Transition experts at KWR are now working on backcasting in order to make this clear. It is still very difficult to construct a comprehensive whole from all these possible techniques and concepts. What is important is that the water sector be closely involved in this project. My feeling is that circularity could be embraced even more widely.’ De Jong illustrates the urgent need for decisive work on circularity with some simple arithmetic. ‘Today we are designing treatment processes that will be built over ten years and then operate for another forty years. We are therefore talking about 2070, which is way after 2050. This means that treatment processes should already be circular today.’

Point on the horizon: a circular water cycle in 2050.

WiCE as connecting factor

With regard to the collaboration between drinking water utilities and Water Authorities aimed at taking the required steps, Van der Wal sees, as a member of the programme’s core team, a key role for WiCE. ‘The research programme provides an environment in which the possibilities can be objectively explored, with due regard to each other’s interests. This creates connection. Research is needed to bring about a circular water cycle. What WiCE shows us is that the water sector must learn to think very differently. Only four years ago, when WiCE was set up, the drinking water utilities were primarily occupied with traditional themes, such as the chemical and biological safety of water. These themes are still important, but the research approach is now much broader – look at the example of the certified calcite pellets. Our mission is to make water valuable. From a technical point of view, a lot can already be done. The discussion becomes interesting as soon as we also start taking sustainability into account in our business case. We already see how well this works in the reduction of our CO₂ footprint. The same direction needs to be taken with circularity.’