An Assessment of Options to Improve the Removal of Excess Nutrients from European Wastewater

In this contribution we quantify the potential to reduce the discharge of excess nutrients with European wastewater, by modelling pollution, greenhouse gas emissions and the costs of measures under various scenarios. We analyse two types of strategies, namely extending the requirement of nutrient removal to broader areas and increasing the removal efficiency of nitrogen and phosphorus. As the former strategy usually entails some infrastructural investment while the latter entails an optimization of the existing processes, the two imply different costs, and increasing efficiency usually shows a better cost–benefit ratio. In any case, actions increasing nutrient removal are expected to pay for themselves in terms of the benefits they bring in abating water pollution and (for nitrogen) greenhouse gas emissions. Nitrogen removal becomes even more attractive whenever the infrastructural investments that we assume may be avoided, thanks to the possibility of an optimized use of the existing infrastructure. Phosphorus removal may become even more attractive with the progress of technologies for its recovery from wastewater and sludge, and with the increase of its demand for fertilizers and other industrial uses.