Environmental Technology

Advances in Water Reuse in the Mediterranean Region

Throughout the Mediterranean region, water needs are evolving due to the effects of climate change: decreases in precipitation and increases in temperatures require us to rethink water management models, both in terms of quantity and quality, for all human (agriculture, drinking water, industry) and non-human activities (flow and quality of watercourses).

Wastewater from human activities is now considered as an often underutilized or misused resource, both quantitatively (for improved water reuse) and qualitatively (for increased reuse of its fertilizing nutrient components and for the limitation of direct discharges into the environment). However, like any modification of the water cycle, implementing solutions that promote shorter cycles, wastewater reuse, and more broadly, so-called "non-conventional" waters, can impact the environment to varying degrees, especially aquatic environments and our communities. It is therefore necessary to consider reuse projects as a component among others in the integrated management of water resources, concomitantly with measures aiming to promote water savings.

To respond to this challenge, the first REUSE EUROMED international conference was held in Montpellier, France, from 29 to 31 October 2024. Co-organized by the French Association on Water, Agriculture and Territories, the academic chair of Montpellier AGRO Institute in Water, Agriculture and Climate change, and by the French National Institute in Food, Agriculture and Environment (INRAE) research network on reuse, the event brought together over 300 participants from 14 countries from the Mediterranean region. Representation was from those with a keen interest in water management from the private sector, local authorities, public institutions and academia. The reuse of treated wastewater was discussed from multiple perspectives, including health and environmental risks, associated treatment processes, agricultural uses and project governance. A great deal of feedback was shared by stakeholders involved in research and projects that have been deployed in various areas around the Mediterranean.

Topics covered focused on the multiple facets related to the reuse of treated wastewater and "non-conventional" waters at various scales, from individual households to territories, including:

• rainwater and greywater for uses at the residential and neighborhood level;
• wastewater from treatment plants for agricultural irrigation or urban purposes to clean or ‘green’ cities and fight against heat islands;
• drainage water for irrigation;
• water for agro-industrial and agro-food uses.

This special issue will bring together extended versions of some of the most influential papers presented at the conference.