Wastewater, whether from municipal or industrial sources, contains various pollutants, primarily: solid debris and grit; greases; organic matter (suspended and dissolved solids); nutrients; pathogens; and emerging contaminants. If not managed correctly, such wastes discharged into water bodies can degrade aquatic ecosystems and increase toxicity and water stress.
Although installation of wastewater treatment plants to handle wastewater is an obligation in the European Union, most plants are not designed to recover energy and resources from wastewater. They are also not designed to monitor and remove emerging contaminants. At the same time, a major challenge for wastewater treatment in the EU is to cut treatment plant operating costs and energy consumption (and thus carbon footprints). Depending on treatment plant size and technology, average operating costs are ?0.20-0.40 per cubic metre of wastewater, with secondary treatment being the most expensive stage of the process.
The LIFE GREEN SEWER project will design, build and operate a pilot system that will treat 12 cubic metres/day of primary effluent at two wastewater facilities: in Muros (Galicia, Spain) and Abrunheira (Mafra, Portugal).
The system will involve a new secondary wastewater treatment process to reduce the presence of pathogenic microorganisms and emerging contaminants. The process will involve Forward Osmosis-Reverse Osmosis preconcentration (FO-RO) as well as an Anaerobic membrane bioreactor (AnMBR) with ultrafiltration membranes. The process will be capable of recovering biogas, reusable treated water as well as a nutrient rich stream from wastewater, in line with circular economy principles, while cutting energy consumption and water losses. The process?s environmental, social and economic impact will be estimated, and the new process will be promoted as an alternative secondary wastewater treatment. It is expected the process can reduce the costs of secondary treatment of wastewater.
The project will contribute to improved wastewater treatment in the EU and will help with the implementation of Directive 2013/39/EU, which aims to tackle pesticides and other priority substances in water.