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October 2023

Archer Western delivers upgrades to St. Vrain Wastewater Treatment Plant

Firestone, Colorado - Archer Western has completed improvements to the St. Vrain Wastewater Treatment Facility, finalizing the $31 million of upgrades at the Firestone, Colorado plant. Archer Western and HDR Engineering converted the two existing oxidation ditches to two bioreactors, delivered new Autothermal Thermophilic Aerobic Digestion and Storage Nitrification/Denitrification Reactor systems, provided a new anoxic zone expansion, constructed a new dewatering building and upgraded a waste activated sludge tank.

The upgrades were necessary due to the continued growth in the area and more stringent regulations on Nitrogen and Phosphorous from the State of Colorado and EPA along with solids processing at 70% to 80% capacity at the time, according to the St. Vrain Sanitation District.

The project triples the size of the Anaerobic treatment tanks and converts an Oxidation Ditch to a more efficient Single Pass Bioreactor with fine bubble diffusers. The bioreactor and the added anoxic zone to each Bioreactor allow the same organisms to treat a larger amount of waste, resulting in a treatment capacity increase from 3 million gallons per day (“MGD”) to 4 MGD, and increasing overall capacity from 6 MGD to 8 MGD.



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