How can water reuse contribute to a more robust freshwater system?

The current human water system in the Netherlands. The figures indicate water volumes in Mm3/year. The net pressure on groundwater is given in Mm3/year. The flows exclude cooling water for industry. For agriculture, the volumes indicate the irrigation water demand.

Examples of water reuse

The Sankey diagrams produced by KWR visualise the freshwater system for the Netherlands and Flanders, with a focus on water streams that are influenced by humans. Researchers began by quantifying the current freshwater system and the impact of a future scenario in which economic growth and population increase result in greater water demand, while the availability of water actually decreases because of climate change. Then, focusing on water quantity, they determined the highest possible contribution the different kinds of water reuse could make to address the shortages. The study examined various examples of water reuse: reuse of highly treated household residual water in agriculture or industry; reuse of highly treated industry water in agriculture; and active infiltration of highly treated residual water for groundwater recharge. Besides these examples, there are also a variety of other possible applications and water reuses in different sectors.
An integrated view of water reuse.

Clarifying opportunities and risks

The responsible implementation of water reuse is extremely important. It demands the systematic analysis of the treatment requirements, of how to safeguard chemical and microbiological safety, of how water reuse fits in with the existing or future regulations and perceptions, and of the potential environmental consequences. KWR has developed expertises in all of these areas. This knowledge comes together within this theme: both the opportunities and risks of water reuse are clarified.

Water reuse reduces load on groundwater resources

The analysis of the Sankey flow diagrams shows that whenever water reuse is applied, it has the potential of considerably reducing the load on the groundwater resources. Particularly the creation of new connections between sectors presents opportunities. The method used clearly reveals the connections in a regional freshwater system, and supports stakeholders in identifying possible collaborations. It also reveals the problem areas concerning water quality. A next step would be to create a dynamic model for the distribution and the supply of water in space and time, as well as to develop a method to deal systematically with and interconnect the non-quantitative aspects.

Connection between sectors in the water system.