LAUSR

Abstract The use of anaerobic membrane bioreactor (AnMBR) technology on urban wastewater can help to alleviate droughts, by reusing the water and nutrients embedded in the effluent in agriculture (fertigation) in line with Circular Economy principles. The combination of AnMBR and fertigation reduces CO2 emissions due to the organic matter valorization and the partial avoidance of mineral fertilizer requirements. However, both AnMBR and fertigation still face technological and regulatory barriers that need to be overcome. These bottlenecks were tackled within the first Innovation Deal approved by the European Commission in 2016, and gave rise to several case studies on water reuse systems. The results of the Oliva Wastewater Treatment Plant (Spain) and Peschiera-Borromeo Wastewater Treatment Plant (Italy) showed that reclaimed water can be considered as a reliable water and nutrient source, return a positive economic balance (up to 376 k€·year−1) and provide significant reductions and savings in CO2 emissions (up to −898.9 tCO2·year−1). According to the new EU regulation, a new key player known as the Reclaimed Water Manager, was also proposed to be in charge of supplying reclaimed water with appropriate quantity and quality to end-users. This new agent would also be responsible for drawing up and implementing a Water Reuse Risk Management Plan in cooperation with the parties involved. Applying AnMBR technology to water reuse thus shows potential for contributing to catchment-scale Circular Economy while preserving natural water bodies, reducing the carbon footprint and creating new business opportunities. However, to take full advantage of its benefits demonstration projects would need to be carried out and favorable and harmonized regulations among the EU States would need to be adopted.