Researchers from AQUAELECTRA Project have developed a system of wastewater treatment based on an electrically conductive biofilter. This system attempts to solve some of the problems that arise during the water treatment, in which oxygen is a significant portion of operating costs, while it generates a large amount of biomass, or sewage sludge, due to the high growth yield from aerobic microorganisms.

The system designed by researchers from IMDEA Water, CENTA Foundation and Euroestudios, all consortium members, is based on the capacity that certain conductive materials have to stimulate the exchange of electrons between organisms and their environment. The conductive biofilter, which has been the object of the patent of invention, consists of a device filled with inert electrically conductive particles, acting as physical support for electroactive biofilm growth. This biocompatible bed favours oxidation reactions, increasing the ability of microorganisms to transfer electrons generated during these reactions to a final electron acceptor, generally inorganic compounds. One of the most innovative aspects of this system lies in its application to the construction of artificial wetlands to favour the oxidation or removal of organic matter present in the wastewater, significantly reducing the wetland dimension and minimizing the production of sludge or biomass, thus attenuating the phenomena of clogging of the filter substrate.

The technology can be applied to wastewater treatment in general and it is currently being tested at treatment plant scale. International patent holders are IMDEA Water, CENTA Foundation and Euroestudios as requesters and Abraham Esteve Núñez and Antonio Berná y Alejandro Reija, from Bioelectrogénesis group of IMDEA Water, and Juan José Salas Rodriguez, Juan Ramón Pidre and Carlos Aragón, from CENTA Foundation, as inventors.