Background Eutrophication can occur when a body of water acquires a high concentration of nutrients - phosphates and nitrates – from agricultural, industrial and urban effluents. The nutrients can cause excessive growth of simple organisms such as algae, blocking out light from the water and leading to the depletion of available oxygen through the decomposition of dead organic matter. These changes in water quality can eradicate more complex species of plants and animals, reduce the aesthetic and recreational value of the water body and can even create risks to human health. Systems to efficiently remove nitrogen have been successfully developed; however the elimination of phosphorus components still needs to improve. European legislation has set a target of 80% phosphates removal and more efficient processes are needed to achieve this target in an affordable way. Currently, several EU countries including Germany, UK, France and Spain, experience river phosphate concentration levels that reach over 500 μgP/l in many cases. This is way over recommended levels. Research has shown the critical levels of phosphate concentration leading to an incipient eutrophication are 100-200 μgP/l for flowing waters and just 5-10 μgP/l for calm waters. Objectives The LIFE-REMPHOS project aims to develop a more efficient and cost-effective technology for removing phosphates from wastewater that will be suitable for both industrial and urban wastewater treatments plants (WWTPs). Specifically it aims to effectively demonstrate valorisation of a by-product of magnesite production as a precipitating agent to remove phosphates from wastewater. The project will develop a new precipitation agent for the removal of phosphates from wastewater made of 63% magnesium oxide, a by-product of magnesite production. It hopes to demonstrate valorisation of this by-product, for which no feasible use or economic value has been found previously. It will test the new precipitation agent in a pilot plant consisting of a Continuous Stirred-Tank Reactor (CSTR) implemented as a tertiary treatment in the WWTP after the nitrate-removal phase. It hopes to demonstrate successful reductions in phosphate concentration in the wastewater by chemical precipitation. The project seeks to demonstrate that the technology can achieve European legislative targets on the removal of phosphates from wastewater in a way that is more cost-effective than current chemical and biological treatment solutions. Economic and other environmental benefits will arise from the use of an industrial by-product instead of freshly mined raw materials. It also hopes to find potential management solutions for the precipitate resulting from the treatment process. Expected results: The project expects to achieve the following results: Valorisation of a magnesite by-product as a precipitation agent; A pilot plant able to treat 480 m3/day of wastewater; Phosphate removal efficiency of 83-91%; Increased cost-effectiveness in comparison with current treatment solutions; Decreased risk of eutrophication from phosphate-laden effluents; A contribution to the achievement of the water quality targets of the Water Framework Directive; A demonstration of the applicability of the technology to either industrial or urban WWTPs; and Development of an effective way to manage the final precipitate from the treatment process.