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Authors: John Rehring, PE; Jason Assouline, PE; Shaun Thomphson; Birgit Landin

Currents: Volume 2, 2022

Currents 2022 Volume 2

Direct Potable Reuse Mobile Demonstration: The first-of-its-kind direct potable reuse (DPR) mobile demonstration system for Colorado’s sustainable water future

In 2015, the Colorado Water Conservation Board (CWCB) published the Colorado Water Plan, a comprehensive statewide framework that addresses the present and future water challenges facing communities across Colorado. The plan concluded that, even with aggressive conservation, Colorado will encounter significant water supply shortages by 2050. By the same year, the state’s population is expected to double current values, which will not only place heavy burdens on natural resources and existing water collection and conveyance infrastructure, but also exacerbate the state’s strain under frequent drought conditions.

Colorado Springs Utilities Water Stewardship and Reuse Efforts 
Located in south-central Colorado, Colorado Springs Utilities (Springs Utilities) relies heavily on water  conveyed from other parts of the state. In fact, 60 to 70 percent of their water comes from the opposite side of the Continental Divide, traveling up to 100 miles to meet the needs of their customers. As the largest Colorado city that does not reside on a river or a major stream, Colorado Springs has long spearheaded water stewardship and reuse efforts that make the most out of resources available to them, including pioneering the use of reclaimed water for non-potable irrigation use in the 1960s.

World’s First Carbon-Based Mobile DPR Demonstration
Anticipating the potential role of direct potable reuse (DPR) in the coming decades, Springs Utilities forged  a unique partnership between engineers, academics, and state agencies to design, construct, and successfully utilize the PureWater Colorado Mobile Demonstration Project, a traveling DPR demonstration system. The first-of-its-kind in the world, this small but mighty advanced water purification system treats secondary- or tertiary-treated wastewater to federal and state drinking water standards without
producing a waste stream that requires disposal.

To demonstrate compliance with anticipated DPR regulations and remove emerging constituents, Carollo designed this system with ozonation, biologically active filtration (BAF), microfiltration, granular activated carbon (GAC), and ultraviolet (UV)/advanced oxidation. Built by dedicated students, staff, and faculty from the Colorado School of Mines, the system can purify 5 gallons per minute, and its state-of-the-art process train comprises accessible technologies that can be scaled up to an advanced purification plant that produces millions of gallons of water per day.

Supported by a $350,000 grant from the CWCB, this project was planned and operated in consultation with the Colorado Department of Public Health and Environment (CDPHE), who, by closely following the development and success of the demonstration, gained key context for DPR regulations that will serve Colorado. By setting achievable but uncompromising water quality standards, other municipalities can begin evaluating the benefits and feasibility of such reuse projects under prudent guidance. CDPHE expects to finalize these regulations by 2023.

Community Engagement and Education
While regulatory advisement was a key benefit, the DPR system’s primary purpose while stationed in Colorado Springs was to engage and educate members of the public on the safety, sustainability, and efficiency of DPR. The project was well-received by the community, demonstrating interest in working to achieve a water-secure future for Colorado. For instance, beverage producers in the area partnered with Springs Utilities to make beer, hard seltzer, and soda using the system’s purified water to further extend awareness and education in the community about DPR and sustainable water management practices — in January 2022, Carollo officially partnered with Springs Utilities and Storybook Brewing to brew and can a batch of amber ale, dubbed “Recycle Amber” to highlight the purified water used for brewing.

WateReuse Award for Excellence

The PureWater Colorado Mobile Demonstration Project received the prestigious Award for Excellence in Outreach and Education from the WateReuse Association at its 2022 Annual Symposium in San Antonio. The national award recognizes the leadership of Colorado Springs Utilities, Colorado School of Mines, and Carollo in fostering community education on DPR and forwarding the principles of sustainability water reuse, and environmental stewardship.

Read more of this issue of Currents: Currents: Volume 2, 2022