Built-to-Last: Gas Collection Cover Lasts 20 Years

Current biogas cover replaced with updated design without interruption to the wastewater treatment system

Creston is a town of approximately 5,000 people in southern British Columbia, Canada. Since 1959, Kokanee beer has been brewed in Creston at the Columbia Brewery, now owned by Anheuser-Busch InBev.

Challenge

The Town of Creston wastewater treatment facility treats both domestic and industrial (brewery) wastewater. The brewery wastewater has been treated anaerobically since a digester was installed in the early 1990s. Evoqua’s Geomembrane Technologies provided the liner and gas collection cover for the original system. After 20 years of successful service, the biogas collection cover required replacement. So as not to impact the operation of the system and the brewery, the town had to keep its anaerobic digester in service while the cover was changed.

Solution

Evoqua’s Geomembrane Technologies replaced the cover with a newly-updated cover design—without shutting down Creston’s wastewater treatment system. The old cover was removed and the new cover installed in less than two weeks.



The covers incorporate updates that reliably collect biogas produced from the anaerobic digestion process, all while resisting the elements. Anaerobic digesters pose demanding challenges for covers since the biogas and wastewater are corrosive and aggressive towards all materials.

At the same time, the cover resists UV exposure, wind, precipitation, and temperature changes. The cover is fully insulated to protect against heat loss during winter months and is safe for operators to walk on. The floating beams provide additional buoyancy, large gas migration paths, and ensure a quick installation with little to no impact on plant operations.

Results

The Town of Creston is now equipped with a state of the art digester cover, designed to last for two decades or longer. The new Evoqua Geomembrane Technologies™​ brand gas collection cover is a critical component of the waste treatment system, and does many things including:

  • Allowing biogas to be handled and burned in the boiler safely
  • Offsetting operational costs for the treatment facility​
  • Controlling foul odor
  • Minimizing harmful greenhouse gas emissions​
  • Helping maintain proper temperature within the anaerobic digester