An energy self-sustainable prototype for post-treatment of secondary wastewater effluent with agricultural reuse purposes

Wastewater reuse presents a promising way to mitigate the global water resource risks and achieve sustainability in water, especially in agricultural areas with increasing scarcity of freshwater such as the southeast of Spain. At European level. In 2018, the European Commission put forward a proposal for a regulation setting EU-wide standards that reclaimed water would need to meet in order to be used for agricultural irrigation, with the aim of encouraging greater use of reclaimed water and contributing to alleviating water scarcity. The Commission estimates that the proposal could increase water reuse in agricultural irrigation from 1.7 billion m³ to 6.6 billion m³ per year, thereby reducing water stress by 5 % (EU, 2018). The use of reclaimed water requires a quality control for each use, guaranteeing satisfactory sanitary conditions. In Spain, the quality of reclaimed water is regulated by Royal Decree 1620/2007, which established the legal framework for the use of reclaimed water for different purposes. However, the presence of certain pollutants that are not found in the current legislation (as the so-called "emerging contaminants, ECs") and the lack of information on the risks that an extended use of reclaimed water can pose for public health, constitute a serious obstacle to generalize the use of this practice.