ReWater – Future Irrigation with Treated Wastewater

The work combines continuous monitoring of effluent water quality with controlled field‑based lysimeter experiments. Water samples are analysed for microbiological and chemical indicators, while crop growth, yield, nutrient composition, soil characteristics, and leachate quality are followed throughout the growing season. This integrated approach provides a solid scientific basis for assessing both the benefits and potential risks associated with irrigation using treated wastewater.

The project also identifies regulatory requirements and practical considerations for safe and effective implementation. This involves evaluating the availability and proximity of water from treatment plants, logistical possibilities for transport and distribution, suitable irrigation infrastructure, and appropriate monitoring routines. Together, these insights contribute to guidance that can support treatment plants and agricultural stakeholders in adopting treated wastewater as part of a more circular water system.

Progress to Date

Two full seasons of water‑quality monitoring have been completed, and the extensive lysimeter trials have been carried out. Collaboration between the water and agriculture sectors has strengthened, and several treatment plants show potential to supply irrigation water that meets safety and quality standards.

Summary of 2024 Experimental Results

The 2024 lysimeter trials showed that both grassland and sugar beet produced higher biomass when irrigated with treated wastewater compared with drinking water. Nutrient concentrations in plant tissues differed by water type, but no harmful substances or phytotoxic effects were detected. Leachate analyses showed differences in nutrient movement through the soil, while PFAS, antibiotics, and E. coli remained at consistently safe levels. Overall, the results indicate that treated wastewater can function as a safe and effective irrigation source under Swedish conditions.

Next Steps

In the final phase, results will be synthesised into practical guidance for real‑world use. Remaining analyses will be completed, and the project team will prepare both scientific publications and accessible summaries. The project’s findings will also be presented at national and international conferences.