Sustainable futures
Sustainable water use and its role in a changing climate
As the urgency for sustainable resource management grows, wastewater reuse is emerging as a key strategy for addressing global water scarcity, particularly in agriculture.
This article explores the critical role of wastewater reuse in building water resilience, with a spotlight on new research conducted in Mexico’s Tula Valley, one of the world’s largest agricultural regions using wastewater for irrigation. The study identified over 100 previously unmeasured contaminants of emerging concern (CECs), shedding light on both the potential and the risks of wastewater reuse.
The importance of wastewater reuse in agriculture
Wastewater reuse for irrigation is a well-established practice that provides a sustainable solution to water scarcity. It is particularly significant in regions where water resources are limited, such as the Tula Valley in Mexico, one of the world’s largest agricultural areas utilising wastewaters for irrigation. Wastewater is available year-round and contains valuable nutrients that enhance soil fertility, aligning with multiple United Nations Sustainable Development Goals (SDGs), including Zero Hunger and Clean Water and Sanitation.
Despite its benefits, wastewater reuse also presents challenges, particularly concerning contaminants of emerging concern (CECs). These pollutants, including pharmaceuticals, pesticides, and industrial chemicals, may pose environmental and health risks. While research on CECs is advancing in the global north, studies in the global south remain limited, leaving critical knowledge gaps.
Assessing contaminants of emerging concern in Tula Valley, Mexico
To address these gaps, a study was conducted in the Tula Valley to identify and analyse CECs using both targeted and untargeted methods. This research, which was co-led by Rachel Gomes, Professor of Water & Resource Processing, uncovered over 100 pollutants previously unmeasured in the region, including pharmaceutical metabolites and agricultural chemicals like the herbicide, fomesafen. Additionally, ten key contaminants, such as acetaminophen, diclofenac, and sulfamethoxazole, were found to pose potential environmental risks in this area.
Overall, the findings highlight the importance of local studies in ensuring wastewater reuse remains a viable and safe practice. Understanding the presence and impact of CECs enables policymakers and scientists to develop appropriate mitigation strategies, such as improved wastewater treatment technologies tailored to regional needs.
A global perspective: Wastewater reuse and water conservation
The issue of wastewater reuse extends beyond agriculture; it plays a critical role in global water conservation. As freshwater sources continue to decline, sustainable water use becomes increasingly urgent. By treating and reusing wastewater, we reduce dependence on shrinking freshwater reserves, easing the strain on vital water systems.
Moreover, responsible wastewater management can complement broader efforts to protect freshwater ecosystems. For example, balancing nutrient retention for agriculture with improved contaminant removal can enhance both food security and water quality. Therefore, future research should explore the long-term impact of wastewater irrigation on soils and crops, ensuring the practice remains beneficial without unintended environmental consequences.
"Wastewater reuse, especially in agriculture, offers a practical and often underutilised solution to water scarcity. When managed responsibly, it reduces pressure on freshwater sources, enhances food security, and contributes to the broader goal of living within planetary boundaries."
Looking forward: Sustainable solutions for water security
Sustainability is not just a principle, but a necessity in the face of escalating environmental pressures. The way we manage our natural resources, especially water, will define our ability to adapt to climate change, protect ecosystems, and support human well-being. Among the many urgent priorities, sustainable water use remains central to reducing our ecological footprint.
This discussion is particularly timely as the UK marks its Earth Overshoot Day, a point in the calendar when our demand for ecological resources exceeds what the planet can regenerate in a year. Water use is a critical part of that equation. Reimagining how we treat, reuse, and value water is essential to building resilience in a rapidly changing world. By improving wastewater treatment and monitoring CECs, we can maximise the benefits of wastewater reuse while minimising risks.
Moving forward, expanding research in the global south, developing locally adapted solutions, and strengthening international collaboration will be key to ensuring equitable and sustainable water management. With responsible practices, wastewater reuse can continue to be a powerful tool for water conservation, helping to secure a resilient future for communities around the world.
This case study forms part of the Institute for Policy and Engagement’s ongoing campaign highlighting research that showcases how the University of Nottingham is advancing the Sustainable Development Goals at different levels.