Gladstone Interim Water Treatment Plant

Project Highlights

  • Ensero successfully designed, constructed and commissioned this treatment plant within 21 days of contract award.
  • Our plant design achieves metal load reductions exceeding 93%.
  • Our innovative and cost-saving sludge management approach saved the client over $800K/yr in operations cost.
  • The plant operates 24/7 year-round above 10,000 feet of elevation.

The Challenge

The Gold King Mine is located near Silverton, Colorado at 10,500 ft in the San Juan Mountains. Abandoned in 1923, the mine accumulated water in the underground workings that became a potential source of metals-laden acid drainage. In August of 2015, a contractor working for the United States Environmental Protection Agency (EPA) inadvertently damaged the portal plug, and approximately 3 million gallons of water/sludge was released from the mine into Cement Creek, a tributary of the Animas River. This was a high-profile situation garnering national attention. An immediate solution was needed to mitigate ongoing and prevent future natural resource damage. The situation was complicated by the remote location, geographic setting within a drainage offering very little space for water treatment, and high elevation causing difficult climatic conditions.

Cement Creek

The Ensero Solution

Water Treatment Plant

Ensero was selected by the EPA Emergency Response contractor through a competitive bid, to design, build, and commission an interim treatment facility within 21 days of notice to proceed. Specific metrics included treating mine discharge up to 1,000 gpm and operating the plant throughout the winter. Other design parameters included handling pH levels from 1.8 to 4.5 and elevated metals concentrations (aluminum, cadmium, copper, iron, manganese, and zinc).

With the limited time available for design and equipment selection, Ensero leveraged an extensive list of vendors in the western US to provide equipment to meet the critical schedule for installation and commissioning. The treatment system included dosing hydrated lime from a vertical silo/slurry tank to a large reactor tank followed by settling in a lamella clarifier. The system was connected to the on-site controlling programmable logic controller (PLC) which allowed the system to automatically adjust lime feed rates based on continuous pH monitoring.

Geotextile bags

Ensero’s innovative sludge management approach utilizing geotextile bags allowed EPA to save roughly $800k/year in labor and equipment costs that were anticipated due to the typical severe winter weather conditions. Ensero also designed/installed a back-up generator and automatic transfer switch to ensure continuous treatment considering the un-reliable grid power, especially in extreme storm conditions and avalanches.

Ensero continues to operate the water treatment plant year-round, with an average reduction of metal loading by 93% prior to discharge. Although initially intended to be an interim measure, Ensero recently implemented design improvements intended to extend the plant life for 5 more years. Additionally, we implemented operational changes to accommodate occasional influent from the American Tunnel, Red Mine and Bonita Mine when other work at these locations produce water discharge.


For more information about the Gold King Project,
Please download a project summary and contact us today.

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