Setting global standards: Inside North America’s only full-scale UV disinfection validation facility

Ultraviolet (UV) disinfection has become a critical tool for protecting public health in drinking water, wastewater, reuse, and advanced treatment systems. But before UV reactors can be trusted to inactivate pathogens at full-scale, they must be rigorously tested under real-world conditions. That testing is what turns promising technology into reliable infrastructure.

That behind-the-scenes work is the focus of a recent article published by Water Online, “Setting Global Standards: Inside North America’s Only Full-Scale UV Disinfection Validation Facility.” Written by Carollo’s Mark Heath, Harold Wright, and Traci Brooks, the article takes readers inside the Portland UV Disinfection Validation Facility as it marks a major milestone: its 100th UV reactor validation after 23 years of operation. More than a local achievement, the milestone highlights the facility’s global role in shaping how UV disinfection systems are tested, approved, and trusted to protect public health.

Inside North America’s Only Full-Scale UV Validation Facility

Established in 2002 through a partnership between Carollo Engineers and the Portland Water Bureau, the Portland UV Disinfection Validation Facility was created in response to the U.S. EPA’s draft UV Disinfection Guidance Manual. That guidance required full-scale validation testing for UV systems used in drinking water applications, creating the need for a dedicated, independent testing site.

What began as a modest operation—with diesel generators and temporary structures—has evolved into the only facility of its kind in North America and the largest of just four worldwide. Today, the facility includes multiple high-capacity test trains, large-diameter supply and discharge piping, and the electrical infrastructure needed to test the most powerful UV reactors on the market.

Validating Ultraviolet Reactors at Full-Scale

Over 23 years, the Portland facility has validated 100 commercial UV reactors from 17 international manufacturers. These systems span drinking water, wastewater, water reuse, and advanced oxidation applications, with tested flows ranging from just 5 gallons per minute to 72 million gallons per day.

According to the authors, a 2022 survey of major UV suppliers found that nearly 300 cities worldwide are using UV reactors validated in Portland, representing more than 13 billion gallons per day of treatment capacity. That reach underscores how a single validation facility can influence water quality far beyond its geographic footprint.

Shaping UV Disinfection Standards and Guidance

The impact of the Portland UV Validation Facility extends well beyond individual reactor tests. Its work has directly informed how UV disinfection is regulated and implemented globally. Research conducted at the facility has supported improvements in UV dose algorithms, sensor performance, quality assurance practices, and validation methodologies.

The facility has contributed to cornerstone guidance documents, including the final U.S. EPA UV Disinfection Guidance Manual, EPA’s Innovative Approaches for Validation of Ultraviolet Disinfection Reactors, and the National Water Research Institute’s 2025 guidelines for UV disinfection, photolysis, and advanced oxidation. Together, these documents define how UV disinfection is applied across the water sector.

One notable advancement described in the article is the development of new UV dose algorithms that eliminate the need for online UV transmittance monitoring, making UV disinfection more accessible and cost-effective for smaller systems.

A Lasting Impact on Water Treatment Worldwide

Reaching 100 UV reactor validations is more than a numerical milestone. It reflects decades of collaboration, research, and technical rigor that have helped utilities around the world deploy UV disinfection with confidence.

Read the full article in Water Online to learn more about the Portland UV Disinfection Validation Facility, its global influence, and how it continues to shape the future of UV disinfection.