Direct potable reuse (DPR), in which purified municipal wastewater is introduced into a water treatment plant intake or directly into the water distribution system, is becoming an increasingly attractive alternative to developing new water sources (Tchobanoglous et al., 2011). The rationale for DPR is based on the technical ability to reliably produce purified water that meets all drinking water standards and the need to secure dependable water supplies in areas that have, or are expected to have, limited and/or highly variable sources. To meet the purification level required, wastewater treated by conventional means undergoes additional treatment steps to remove residual suspended and dissolved matter, including trace organics. Questions of public acceptance are answered, in part, by the successful incorporation of DPR in the small resort town of Cloudcroft, New Mexico; by the Colorado River Water District serving a population of 250,000 in Big Spring, Stanton, Midland, and Odessa, Texas; and by the results of a recent public acceptance survey (Macpherson and Snyder, in press).
The focus of this white paper is on the role that DPR will have in the management of water resources in the future. For example, in many parts of the world, DPR will be the most economical and reliable method of meeting future water supply needs. The topics considered in this white paper include:
- An examination of beneficial impacts of DPR.
- A case study to demonstrate the relationship between DPR and urban water supplies, agriculture, the environment, and energy conservation, based on Southern California and the California State Water Project.
- The next steps that should be taken by water agencies to prepare for DPR in the future.
BENEFITS OF DIRECT POTABLE REUSE
Direct potable reuse can be implemented to provide a new and stable source of water supply for cities. However, the potential benefits accrued for agriculture, environmental preservation and enhancement, and energy conservation through the application of DPR may be more important.