Else Beekman
Thanks to an innovative solution, small villages in Spain now have an affordable way to treat their wastewater. By cleverly combining artificial wetlands with dried water treatment sludge, the European Life Renaturwat project makes affordable water purification for small villages a reality.
The method is not only four times cheaper than traditional systems but also fully sustainable. According to European Directive 2024/3019, municipalities with more than 1,000 inhabitants are required to provide at least secondary treatment for their wastewater. For many small villages, the high costs of conventional treatment plants made this financially very challenging. Life Renaturwat now offers an alternative: a circular, nature-based system that enables affordable water purification for small villages without compromising on quality.
The technology has been successfully tested in Carrícola (200 inhabitants) and the Los Monasterios urbanisation in the municipality of Puçol, near Valencia. It combines two types of wetlands: one using dried treatment sludge to filter chemical pollutants, and another with free-flowing water to promote biological purification.
Treatment sludge as key to phosphorus reduction
Treatment sludge is often associated with pollution. However, in this project, it specifically refers to sludge from drinking water treatment plants. This sludge mainly contains mineral components and very little organic waste. It is dried and stabilised beforehand. Therefore, making it safe to use as a natural filtering material without introducing new contaminants.
Life Renaturwat studies the use of this dried sludge as a filter medium. Tests show it is extremely effective at removing nutrients such as phosphorus and nitrogen from wastewater. Compared to existing systems, this new technology achieves a 75% to 80% reduction in phosphorus levels. This is crucial to preventing eutrophication, the suffocation of water bodies due to excessive algal growth, as seen in the vulnerable Mar Menor.
Moreover, this technique also significantly reduces the presence of bacteria such as Escherichia coli and other micro-pollutants. Which improves the water quality physically, chemically, and biologically.
Broad range of applications possible
According to Nuria Oliver from Global Omnium Medioambiente, the system is suitable not only for urban wastewater treatment but also for industrial processes, wineries, and agricultural slurry management. Portugal already plans to implement this technology in its textile sector, where wastewater treatment remains a major challenge.
The high quality of the treated water also enables reuse. It can be used for irrigating non-food crops, filling urban fountains, or replenishing natural water reserves. All increasingly important applications in the fight against the effects of climate change.
Affordable solution for municipalities and households
Although households cannot install such treatment systems themselves, they benefit indirectly from the advantages of Life Renaturwat. Since municipalities can implement this technology affordably, wastewater treatment costs remain manageable, ultimately reflected in lower water bills for households.
Economically, Life Renaturwat offers significant advantages. “The cost of using treatment sludge is around €70 to €80 per cubic metre. Other alternatives cost approximately €165/m. Including operational costs, the total price for Renaturwat is between €0.47 and €0.52 per m³ of water. A price considerably lower than traditional systems,” says Francesc Hernández, Professor of Applied Economics at the University of Valencia.
Additionally, the environmental benefits and future cost savings significantly outweigh the initial investment. This makes the technology not only effective but also economically sustainable.
Seabed restoration in southern Spain due to the absence of wastewater discharges