O Casal water treatment plant in Vigo recognised as one of the best in the world
The O Casal water treatment plant, located in Vigo, has been awarded Best in Europe and second best worldwide at the 2025 Global Water Awards, international prizes organised by the prestigious British publication Global Water Intelligence. This recognition places the Vigo facility at the forefront of global water innovation, highlighting its efficient management model, cutting-edge technology and strong commitment to environmental and social sustainability.
International recognition for exemplary management
Beating candidates from countries such as the Philippines and Malaysia, and ranking just behind a mega-facility located in Shanghai (a city with over 25 million inhabitants), the O Casal water treatment plant has established itself as a benchmark for the sector. The jury valued not only its operational results, but also key aspects such as resilience to extreme weather events, the use of advanced technology and the project’s adaptability to a geographically limited space.
This award is particularly significant, as the Global Water Awards recognise not only technical excellence, but also innovation, responsiveness to environmental challenges and positive impact on the communities served. In this context, O Casal stood out among dozens of international projects, consolidating its position as a European reference in drinking water treatment.
State-of-the-art technology serving citizens
The O Casal plant was built with an investment of approximately €23 million, and its main mission is to supply drinking water to more than 500,000 people in Vigo and its metropolitan area. The project is part of the Water Supply Improvement Plan promoted by Vigo City Council in collaboration with the concession company Aqualia.
One of the most innovative features of the facility is its ultrafiltration membrane treatment system, a technology that acts as a highly efficient physical barrier against particles, microorganisms and contaminants, ensuring exceptional water quality. This system is still uncommon in Spain, and its implementation at O Casal marks a turning point in national drinking water treatment standards.
This technology is particularly effective in regions such as Galicia, where heavy rainfall can increase water turbidity in reservoirs. Thanks to ultrafiltration, the O Casal water treatment plant can continue supplying clean, safe and high-quality water without interruption.
An adapted, efficient and eco-friendly design
One of the project’s main challenges was its location: the plant had to be built on a reduced plot surrounded by significant geographical constraints. The solution was a compact vertical design in the form of a circular structure, allowing all treatment phases to be housed without horizontal expansion.
This design not only solved space limitations, but also reduced environmental impact. Lower land use, minimal disturbance to the natural environment and improved energy efficiency are some of the key benefits. In addition, the plant incorporates automated processes that enable intelligent control of each stage, optimising energy consumption and operating costs.
Sustainability at the core
Sustainability is one of the pillars underpinning the success of the O Casal water treatment plant. From its inception, the project focused on responsible water resource management, incorporating measures such as internal water reuse, monitoring of the carbon footprint and reduction of treatment-generated waste.
These efforts were highlighted by the jury of the 2025 Global Water Awards, which praised the integration of environmental criteria throughout all stages of the water cycle, as well as the plant’s commitment to the Sustainable Development Goals, particularly SDG 6 (clean water and sanitation) and SDG 13 (climate action).
A source of pride for the city of Vigo
Vigo’s mayor, Abel Caballero, publicly celebrated the award, stating that citizens drink “mineral-quality tap water” thanks to the outstanding treatment provided by O Casal. He emphasised that the city has proven it is possible to invest in sustainable, high-quality infrastructure without sacrificing innovation, placing Vigo “among the world’s elite in water management”.
This recognition not only benefits the local population by ensuring a reliable supply of top-quality drinking water, but also serves as inspiration for other cities seeking to improve their water infrastructure in the face of climate change.
