Direct potable reuse of reclaimed wastewater: It is time for a rational discussion

Water shortage arising from rapid population growth and relocation has produced an unprecedented degree of stress on regional water resources. Engineered solutions to relieve water stress are frequently based on the use of water of impaired initial quality. Chief among these impaired waters is reclaimed wastewater. For the most part, however, the breadth of both acceptable uses and use-dependent degree of treatment for reclaimed wastewater remain to be established. The chief advantages of direct potable reuse (DPR) relative to other forms of wastewater reclamation and reuse are that (i) all wastewater reclaimed for DPR can be readily used in water-stressed areas and (ii) delivery to points of use does not require a separate distribution system. The drawbacks are related to the need for highly competent, continuous on-line verifi cation of water quality and the cost of treating all reclaimed wastewater to meet potable use requirements when only a small fraction will be used for potable purposes. We have attempted to explore those differences, providing quantitative comparisons where possible, to support selection among water reuse options in water-stressed areas.