New water cycles

Circular economy provides a changing way of dealing with water by creating new opportunities for reuse and recovery for new applications. This will lead to a change in our current water infrastructure: central production and drainage will shift to a more hybrid model, in which decentralized, more local water cycles will arise. However, the reuse of water carries with it the risk of spreading toxicity or disease if not properly managed. Due to the increase in the reuse of water or raw materials from it, such risks can also circulate within the water cycle. Such “risk cycling” must be prevented in order to achieve the goal of making the Netherlands fully circular.

Risks and opportunities in reuse cycles

This research identifies possible chemical and microbiological risks for specific cases of reuse in the water cycle. The risks are quantitatively modeled to assess whether the current control measures are sufficient to achieve the desired water quality or whether additional measures are required. Opportunities in the water cycle are also identified. For example, reusing wastewater for irrigation provides the opportunities to not only reduce the stress on local water resources during times of drought, but also help to reduce or eliminate the pollutant load in downstream rivers, by using advanced treatment options to upcycle instead of discharge the wastewater. Based on the results from the model, an optimal solution for each reuse case can be developed to effectively control the water quality and provide a balanced view on the risks and opportunities in each reuse scenario.

Application to real world case studies

The developed methodology will be applied to various case studies of new and existing water reuse scenarios. Cases include the search for new drinking water sources in the Netherlands and grey water reuse in the health sector. These reuse scenarios range in scale from local water reuse scenarios at the business/factory level, to broader searches at the drinking water company level searching for suitable alternatives for drinking water sources.

Decision support for reuse risk management

The results from this research will be combined in a decision support tool that can be used to identify chemical and microbial risks and opportunities for different water sources, treatments and end uses. End users can use this tool to determine, for their specific situation, which opportunities and risks are relevant and what measures they can take to control these risks and optimize their opportunities.