Thornton Water Treatment Plant Replacement
Delivery MethodProgressive Design-Build
The City of Thornton, Colorado, needed a new water treatment plant to replace their existing aged facility and improve the taste and odor of finished water for their 166,000 customers. Garney and Burns & McDonnell formed a progressive design-build team to deliver the new 20 million gallons per day (MGD) plant, which uses a conventional treatment process with the flexibility to treat several source water conditions and exceed current water treatment standards. The plant is one of the City’s two water treatment plants and is able to run year-round, even though winter conditions.
The new plant includes flash mixing, flocculation, sedimentation, an intermediate ozone system manufactured by Suez, biological filtration that includes granular activated carbon, chlorine disinfection, chemical feed facilities, and a new 55,000 square-foot treatment building that required a 45-feet deep excavation and concrete piers drilled to 35 feet deep to support the building. Associated construction work included asbestos contamination mitigation, paving, and new traffic signals to accommodate an additional lane entrance onto Thornton Parkway. Garney crews placed more than 21,000 cubic yards of concrete and 2.5 miles of buried yard pipe on a constricted site.
Start-up and commissioning of the plant largely took place during the COVID-19 pandemic, which inherently caused some challenges. By working together in the progressive design-build environment, the project team successfully reached completion in late 2020.
Best Projects Merit Award in Water/Environment Category, 2021 ENR Mountain States