Advanced wastewater treatment in Knoxville gets a UV boost
Flowing through the heart of Knoxville, Tennessee, Beaver Creek is more than just a local waterway – it’s a 303(d) listed stream, meaning it’s been flagged by the state as needing environmental restoration. A 303(d) designation comes with strict pollution limits for everything from nutrients and bacteria to heavy metals and chemicals.
For the Beaver Creek Wastewater Treatment Plant, run by the Hallsdale-Powell Utility District (HPUD), those tight regulations hit close to home. Their treated water flows directly into Beaver Creek, leaving no room for error. On top of that, their existing disinfection system relied on chlorine – a heavily regulated chemical due to environmental risks.
Faced with tighter regulations and an aging system, the utility knew something had to change. They made a bold move and switched to a chemical-free UV disinfection process. It wasn’t just an upgrade – it was a complete shift in how the plant protects the creek every single day.
Updating an aging system with UV disinfection
Originally built in the 1960s, the Beaver Creek Wastewater Treatment plant needed an upgrade by 2003 as the utility faced effluent discharge violations.
HPUD responded by building a new plant, but it still relied on aging equipment that required frequent maintenance and extra chlorine disinfection on the backend. To solve these problems, consulting engineers at FOXPE suggested alternative disinfection processes, such as UV. The turning point came in 2019, when a severe flood damaged the plant and HPUD decided it was time to implement the disinfection upgrades.
“We had an existing on-site chlorine generation system, and it worked relatively well, but it was quite complex,” says Nick Jackson, Manager of Treatment and Operations at HPUD. “We used a lot more salt, and then we also had to dechlorinate because we have a very tight chlorine limit on the discharge side.”
Achieving disinfection goals without chlorine byproducts
FOXPE solicited proposals for the project and ultimately chose the Xylem Wedeco Duron UV disinfection system. UV systems are safe and effective, eliminating 99.99% of pathogens – including bacteria, viruses and parasites. Considered more environmentally friendly, UV achieves disinfection goals without creating chlorine byproducts or adding harmful chemicals to the water.
“It eliminated bleach disinfection for us, so now we don't have to worry about that,” says Charlie Rush, Maintenance Supervisor at HPUD. “It's all just treated with UV, so there's no chemicals put into the creek.”
Reduced construction costs and lower energy consumption
The Duron system is a 45-degree inclined UV system, available in adjustable bank widths. The UV system also is equipped with an automatic lifting system for ease of maintenance, off-season storage and improved access to all related components.
This flexibility allowed the units to be installed in the plant’s existing chlorine contact basin, greatly reducing the system footprint and construction costs.
During installation, the plant used a temporary Wedeco LBX 1000 UV system to maintain disinfection standards. This closed-vessel system provided uninterrupted water quality during the six-month transition period.
In addition to reduced construction costs, the Duron UV system combines intelligent control with advanced UV lamp and ballast technology, ensuring the correct dose and reduced energy consumption.
Increasing capacity to 30 million gallons per day
The new UV disinfection system at the Beaver Creek plant has been online since March 2021, and plant operators have seen many benefits over the former chlorine system, providing daily disinfection to the effluent water.
Prior to the installation of the new system, the plant struggled to maintain a steady rate of flow, but with the Duron UV system, capacity increased to 30 MGD for full disinfection. During storm events and peak flow periods, the system ensures that the effluent discharged is in total compliance with room to spare.
“In the first year, we took in the highest flow we've ever had,” says Nick Jackson. “We went to the unit, and we just turned it on maximum for a couple of days, and it performed flawlessly.”
The innovative UV technology has helped the Beaver Creek plant transform operations for greater efficiency, productivity and long-term sustainability, while eliminating safety hazards for employees.
Meeting the treatment needs of a growing city
The disinfection upgrade not only eliminates chemical discharges into the creek – it was also designed to address the needs of the growing Knoxville area.
“North Knoxville is definitely a part of a big growth phase,” says Jackson. “This should set us up in service on the disinfection side for quite some time."
In addition to its UV disinfection upgrade, the Beaver Creek plant also uses a membrane bioreactor treatment system, the first large-scale use of this technology for wastewater treatment in the state of Tennessee.
Overall, the plant now has a more effective, sustainable, and safe treatment process that will support a growing community and protect the creek for generations to come.
Discover the full range of Xylem’s advanced wastewater treatment options.