Tratamiento de aguas grises con sistemes hidropónicos : cumplimiento con la legislación para la reutilización de agua

Abstract

Due to the current environmental reality, along with the predictions for the coming years, the future scenarios show an increasingly difficult access to water. Therefore, the interest in water reuse, and in the technologies that allow it, has increased. The regeneration of greywaters, which are less contaminated than conventional wastewater, is presented as a very good option for water recovery. During this thesis, greywater treatment by a hydroponic system (vertECO) was analysed. This Nature based Solution allows the obtention of regenerated water. Water quality for reuse was evaluated according to the parameters defined in the Spanish Royal Decree 1620/2007 and the Proposal for a Regulation of the European Parliament and of the Council on minimum requirements for water reuse. Results showed a remarkable reduction on both the biological parameters (Escherichia coli, Legionella sp.) and the physical-chemical ones (turbidity, total suspended solids and biochemical demand of oxygen), maintaining the electrical conductivity below the limits established by the legislation. This reclaimed water cannot be consumed as drinking water, but it could be reused as water for residential use, for public service and for crop irrigation (depending on the degree of water exposure). Likewise, the possibility of growing edible plants directly exposed to greywater and determining the risk of their intake was determined according to the Commission Regulation (EC) No 1881/2006 of contaminants in food product, with heavy metals (cadmium and lead) analyses in the plants. It was found that, in most cases, direct exposure of edible plants to greywater did not present a heavy metal concentration high enough to be dangerous to human wellbeing. Thus, these plants would be safe of intake by humans