As Thornton has grown over the past 50 years from a tiny town of 6,000, it has accommodated this growth by following its town motto, city of planned progress.
The city’s new preparation for future progress is the installation of UV water treatment systems from Berson/Aquionics.
The closed chamber, medium pressure disinfection systems will allow the city to meet increased demands in water treatment capacity and tightening water quality regulations.
The city’s two water treatment plants, the Wes Brown water treatment plant and the Thornton water treatment plant, serve the needs of 114,000 citizens.
The Berson/Aquionics CrossFlow UV systems were chosen to provide a secondary barrier in the city’s water treatment process.
Three Berson systems from Aquionics work in conjunction with advanced ultra filtration technology at the Wes Brown location, handling flow rates of 50 MGD.
The quality of the source water (the South Platte River) is particularly challenging at this site, as effluent levels from upriver treatment plants can comprise up to 70 percent of the source water.
At the Thornton site, where the quality of source water from clear creek is less of an issue, conventional filtration is combined with two Aquionics systems to handle 20 MGD.
The UV systems eliminate pathogens and reduce disinfection byproducts (DBPs), meeting water quality regulations governed by the US EPA.
At both plants, chlorine is applied after UV treatment for residual maintenance in the distribution system.
With the installation of UV, the amount of residual chlorine needed has been reduced, resulting in a corresponding reduction in DBPs such as Trihalomethanes and Haloacetic acids.
The compact design and high efficiency of the systems were major selling points for the City of Thornton.
According to Thornton, capital cost was not its only consideration Thornton also took into account projected construction, operating and maintenance expenses over time.
The footprint of the units allowed us to retrofit its existing facilities, while the low power consumption will keep our operating costs down.
Maintenance on the system is also low; periodic replacement of the UV lamps can be carried out easily by on-site staff.
An automatic cleaning mechanism keeps lamp sleeves free of organic deposits for consistent UV dosing. Each chamber is also fitted with UV monitors to measure actual UV fluence and dose for record keeping.
With the addition of an optional online transmittance monitor, real time transmittance values are used to automatically adjust the dose pacing of the UV system.