LIFE REMAR: Managed Aquifer Recharge for the Renaturalisation of Wastewater

In the Baix Camp region, the Cambrils wastewater treatment plant (WWTP) in Tarragona lies above a shallow aquifer contaminated with nitrates. This WWTP treats around 4 hm³ of water annually, which is currently discharged into the sea via a submarine outfall. In response to the need to recover this valuable resource and improve water management in the area, the LIFE REMAR project proposes a nature-based solution to reuse the treated water, increase the availability of water resources, improve the condition of the aquifer, and contribute to the conservation of aquatic ecosystems.

The project involves recharging the Baix Camp aquifer with between 3 and 4 % of the water treated at the WWTP through managed aquifer recharge (MAR) technology, specifically a Soil-Aquifer Treatment (SAT) system with reactive barriers, to improve water quality. This system allows the removal of emerging contaminants, pathogens, antibiotic resistance genes, and microplastics, as well as reducing nitrates in the aquifer, among others.

As part of the project, reactive barriers have been installed at the bottom of two 400 m² infiltration basins, each designed to recharge up to 200 m³/day, at the point where the treated water begins to infiltrate into the aquifer. These barriers are made of different natural and porous materials that promote the retention of contaminants through sorption, allowing time for biodegradation to reduce those contaminants that persist after secondary treatment at the WWTP.

This pilot system also uses plants as part of the treatment, among other functions such as preventing clogging. One of the basins has been planted with Typha (a common wetland herbaceous plant), while the other has been left unplanted to allow the spontaneous growth of native species. The system is designed to recharge up to 146,000 m³ of water annually, representing a significant contribution to the reuse of this resource.

In addition, to monitor its efficiency and impact, 8 piezometers have been drilled. These instruments, used to measure the groundwater level within an aquifer, are distributed upstream, downstream, and beneath the basins at different distances, with a slotted zone between 2 and 4 metres within the shallow aquifer of Baix Camp. The piezometers enable monitoring of both the recharge process and water quality throughout the system.

Impact

The results obtained at this pilot scale will serve as the basis for designing the system on a larger scale. It is expected that REMAR will address water management challenges in Baix Camp and inspire similar solutions in other WWTPs across Mediterranean regions facing comparable issues.

The project contributes to greater availability of freshwater for agriculture, the restoration of submarine groundwater discharge areas and coastal ecosystems, benefiting citizens, the community, and the environment in a safe way.

Partners, budget and funding

LIFE REMAR (LIFE20 ENV/ES/000284) is coordinated by the company Comaigua and, in addition to UPC, involves the participation of the Institute of Environmental Assessment and Water Research of the Spanish National Research Council (IDAEA-CSIC), the French National Centre for Scientific Research (CNRS), and the company Mejoras Energéticas.

The project has a total budget of €2,102,975 and a duration of 48 months (2022–2025). It is funded by the European Union’s LIFE programme.