A nature-based solution from researcher Marcos Fernández is awarded an ERC Proof of Concept grant

The solution researcher Marcos Fernández wants to test with his recent ERC Proof of Concept grant is to use plant communities to recover heavy metals from wastewater treatment plants and reuse them in industry. The proposal, called eMINING, also has an obvious environmental benefit, although the economic component represents a paradigm shift in wastewater treatment. The researcher proposes a system organised around plants that combines phytoremediation and phytonickeling, with the aim of removing heavy metals and nutrients from both the effluent and the sludge of the treatment plants, which also allows them to be recovered from the resulting biomass. The scientific work is linked to the researcher's ERC STOIKOS project. Therefore, based on the plant composition analyses from this project and preliminary trials, the performance of the plant species under real conditions in a wastewater treatment plant can be confirmed, and the most suitable species will be combined to recover the maximum amount of chemical elements such as iron, copper, manganese, nickel, zinc, cobalt, cadmium, chromium and lead. At the same time, these facilities reduce the nutrient discharges that cause eutrophication (the accumulation of nutrient mineral salts that leads to massive algal growth) in inland waters, such as nitrogen and phosphorus.

The significant discharge of heavy metals and nutrients into aquatic ecosystems, essentially rivers, is one of the consequences of a wastewater treatment plant's operation. This threatens biodiversity and increases the cost of reusing treated water. Other residues, such as sewage sludge, are incinerated or deposited in landfills, generating CO₂ emissions and posing a risk of the metals present being transferred to aquatic systems.

Furthermore, from 2024 the European Union requires all wastewater treatment plants to implement tertiary treatments for the discharges they release into rivers. However, it is worth noting that only between 10% and 15% of treatment plants with tertiary treatments use nature-based approaches. For this reason, CREAF researcher Marcos Fernández emphasises that eMINING proposes "applying a cost-effective and efficient nature-based solution, which makes regulatory compliance for wastewater treatment plants an economically attractive option, thanks to an additional source of income derived from recovering metals that conventional systems cannot provide".

eMINING's major challenge is to establish protocols and demonstrate economic viability for the solution to be adopted by the industry. The aim behind this proposal is to turn wastewater treatment plants into suppliers of responsibly sourced metals, while  protecting aquatic ecosystems, fostering local and circular economies, and contributing to transform the European market for the treatment of these waters. "We need to test the amount of metal that can be extracted", Marcos Fernández explains, "and I am the link between basic science and the business reality, which is completely new to me".

The idea stems from data obtained through the STOIKOS scientific project, which looked at the amount of heavy metals accumulated by plant species. "With eMINING, we propose recovering these minerals from the effluent and sludge of wastewater treatment plants, rather than from the soil as other agromining projects do", according to Marcos Fernández. The CREAF researcher also explains that he ventured into this field of research “partly out of curiosity", after reading scientific articles on agromining and learning about the work being carried out at the Urban River Lab (UB, CSIC). "I'm excited to launch an initiative that goes beyond pure science", he says.

The ERC Proof of Concept grant is designed to bridge the gap between pioneering academic research and the early stages of commercial or social innovation. It aims to facilitate the exploration of the commercial and social innovation potential of research findings. "I'm very happy", Fernández admits, "the grant confirms that it was a good idea but, above all, it's a major project because I'm venturing into completely new territory for me".