Reclamation of used urban waters for irrigation purposes – A review of treatment technologies

•A review is made on treatment technologies for irrigation with treated urban water.•Technologies for salinity, pathogens, nutrients and metals removal are discussed.•The four main parameters are hardly taken into account simultaneously in literature.•Wetlands and integrated systems studies present complete evaluations on irrigation.

The worldwide fresh water scarcity is increasing the demand for non-conventional water resources. Despite the technology being available for application of treated wastewater in irrigation, the use of effluent in agriculture is not being properly managed in the majority of cases. Industrial countries, where financial resources are available but restricted, face difficulties in some cases related to the lack of a complete definition of irrigation water quality standards, as well as to the lack of monitoring components that determine if the effluent is suitable for such use. The present paper presents a critical review on urban reclamation technologies for irrigation. The technologies are presented by the four most important parameters for irrigation water quality: salinity, pathogens, nutrients and heavy metals. An overview is given of the current, on-going evaluation of different reclamation technologies for irrigation.