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Biogas pipe replacement

Biogas pipe replacement

West Point Treatment Plant Current Projects

Sustainable practices

The process to clean wastewater requires lots of energy, but it also produces energy. At the West Point Treatment Plant, renewable energy is produced from the wastewater treatment process and has helped to power the facility since it opened in 1966.

During wastewater treatment, organic solids are pumped into large tanks called digesters that are heated at 98 degrees. In the digesters, bugs (anaerobic bacteria) break down organic material and kill pathogens. This activity creates digester gas, or biogas, that fuels two internal combustion engines much like how gasoline fuels an automobile engine. These engines in the internal combustion cogeneration system power generators that produce electricity for West Point. The exhaust heat from the engines provides heat for boilers, digesters and occupied spaces. The biogas contains about 60 percent methane but also contains sulfuric acid (a byproduct of the hydrogen sulfide in biogas) that wears down on the pipes that carry the renewable energy.

Project description

The purpose of this project is to replace parts of biogas piping connected to the digesters at West Point that have leaks or corrosion. Plans for this project include:

  • Replacing the biogas piping system for the north and south digester pods
  • Replacing piping of various sizes in the treatment plant’s underground tunnel
  • Building a new pipe over the primary sedimentation tanks to provide redundancy for an existing buried pipe. The existing pipe would be rehabilitated with a method known as cured in place pipe
  • Replacing horizontal beams that support biogas piping in the tunnel

The goal of this project is to bring the corroded biogas piping system into a safe and reliable condition through rehabilitating the existing network and extending the life of the overall system.

This project will be implemented in two phases. Construction will take place entirely within the West Point Treatment Plant area. The construction of Phase 1 was completed October 2020, with Phase 2 construction underway. The construction of the whole project is expected to be completed by 2027.

What to expect

Construction may require temporary partial shutdowns of digesters for inspection, repair and replacement work. Shutdowns are expected to be less than 24-hours for each occurrence. If shutdowns are planned to last longer, neighbors around the treatment plant and Discovery Park will receive advanced notification regarding any temporary closures or planned gas releases.

Community outreach

We provide ongoing updates here as the project progresses.

Digesters at West Point Treatment PlantNorth and South Digester Pods

Contact us

For more information about this project contact Ryan Harlow at:
206-848-0814 or TTY: 711

If you’d like to receive email or text updates on current projects at the West Point Treatment Plant: