Arizona State University recently published a report, Water Reuse in Central Arizona, to inform policy conversation around wastewater in Arizona. The report highlights issues vital to the water sustainability of Arizona and presents a framework to address public policy issues.

By:  Ariane Middel, Dave D. White, and Ray Quay, Decision Center for a Desert City, Arizona State University

In an attempt to inform policy conversations around wastewater use in Arizona, Arizona State University’s Decision Center for a Desert City (DCDC) released a new technical report in February 2014. The report, Water Reuse in Central Arizona, authored by Ariane Middel, Ray Quay, and Dave White, explores issues critical to water reuse, along with challenges and opportunities for the future.

Covering topics including existing and projected wastewater supply and demand, potential for increased competition and costs, the role of public perceptions, and industrial perspectives, the report highlights issues vital to the water sustainability of Arizona and presents a framework to address public policy issues.

The publication is the result of collaboration between Arizona State University, Intel Corporation, and CH2M HILL’s WaterMatch.

Once thought of as just a waste product, communities across the United States are increasingly considering wastewater a valuable resource. In these communities, the effluent from wastewater treatment plants can relieve the stress on overstretched water supplies by replacing other sources for non-potable, or sometimes even potable, uses.

Effluent is currently used in Arizona for urban and agricultural irrigation, industrial purposes, and for recharging groundwater aquifers. According to the new report, effluent reuse in the Phoenix Active Management Area may be as high as 82 percent.

A majority of effluent is used to cool Arizona Public Service’s Palo Verde Nuclear Generating Station. Some of these processes use effluent that has been treated for higher quality, resulting in reclaimed water. Reclaimed water is used to water parks and golf courses, as well as non-edible agricultural irrigation (i.e. for cotton).

This report highlights the current use of effluent as a key water conservation strategy for Arizona’s Sun Corridor—the combined metropolitan areas of Phoenix and Tucson. Though beneficial for helping curb the demand for water in Central Phoenix, effluent offers many challenges for future water managers and decision makers.

A key challenge for producers of effluent will be cost. Wastewater treatment is currently the largest consumer of energy in Central Phoenix. In the future, this process will become even more expensive as wastewater treatment becomes more sophisticated to remove the brine (salt) and pharmaceuticals from water. A key challenge for effluent consumers will be competition.

Thus, the key to keeping water management sustainable is to continue to keep effluent cost-effective in comparison to the cost of pumping groundwater.

In addition to the authors, contributors to the report include Rob Melnick, Executive Dean and John Sabo, Director of Research, each from the ASU Global Institute of Sustainability, along with DCDC staff Sally Wittlinger and Liz Marquez and student interns Rud Moe and Saad Ahmed.

The review is based in part on a series of interviews and expert reviews by representatives from public, private, and nonprofit agencies.

Ariane Middel holds a Master of Science In Geodetic Engineering from the University of Bonn, Germany, and received her Ph.D. in Computer Science (visualization) from a German National Science Foundation (DFG) funded international graduate school at the University of Kaiserslautern, Germany. Dr. Middel is currently a Research Professional at the Center for Integrated Solutions to Climate Challenges in the Global Institute of Sustainability.

Dr. Middel’s primary research interests are directed toward developing climate adaptation strategies in urban environments, specifically addressing the challenges of sustainable urban form, design, and landscape in the face of climatic uncertainty in rapidly urbanizing regions. For the past four years, she has been working on sustainability issues related to urban heat island, water use, and human-climate interactions in cities.


Dave White is an associate professor in the Arizona State University (ASU) School of Community Resources and Development and Director of the National Science Foundation’s Decision Center for a Desert City (DCDC), which studies water-management decisions in the face of growing climatic uncertainty in central Arizona. Dr. White also holds appointments at ASU as Senior Sustainability Scientist with the Global Institute of Sustainability and affiliate faculty with the Consortium for Science, Policy, and Outcomes and the School of Public Affairs. Dr. White’s research focuses on developing theory and methods for linking knowledge to action for sustainable resource management. With DCDC, he has developed and studied processes, outcomes, and institutional forms of boundary organizations for the co-production of knowledge and decisions; identified divergent perspectives between stakeholder groups at the science-policy nexus; and tested competing methods for gathering information on sensitive topics from decision makers. This work has contributed to the development and refinement of new tools and techniques for collaborative environmental decision making such as DCDC WaterSim. Dr. White is a recipient of the ASU President’s Medal for Social Embeddedness. He received his Ph.D. in Forestry from Virginia Tech.

Ray Quay has been associated with the Decision Center for a Desert City project since 2004 as a stakeholder, advisor, and researcher. In his former position as an Assistant Director of the Water Services Department for the City of Phoenix, Ray was involved with DCDC in stakeholder outreach, water demand and heat island research, and in the application of climate change science and research to public adaptation policy and programs. Ray joined the DCDC project in 2010 as an academic professional. His involvement will now include expanding the capabilities and facilitating the use of WaterSIM as a research and public policy tool, expanding DCDC’s stakeholder outreach with water managers and land use planners, facilitating the initiation and development of academic research that is applicable to current and future public policy issues, and participating directly in various DCDC supported research. Ray’s research interests include advanced scenario planning, anticipatory governance, climate change impacts and adaptation, water demand analysis and models, regional growth, and visualization of sustainability and uncertainty.