SEATTLE — Parts of Seattle's Discovery Park are closed Wednesday and Thursday due to construction work at the West Point Treatment Plant.
The lighthouse, beaches and nearby beachfront parking lot will be closed.
This work is part of a King County pipe replacement project at the treatment plant. Crews will replace a pipe that carries biogas that generates electricity. Replacing the pipe will require a planned release of biogas, which will emit a sulfur or rotten egg-like smell that will be noticeable to those near the plant.
Biogas is is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide. It is produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste, according to the U.S. Energy Information Administration.
To limit the impact on park users and neighbors, the pipe replacement was expected to begin at 3 a.m. on Wednesday, Sept. 7, and will continue until the new pipe is installed and operational. King County said work will be completed on Thursday, Sept. 8, and will re-open closed areas of Discovery Park when it is safe.
King County is working with Seattle Parks and Recreation and local police and fire departments to enforce the closures. There will be closure signs at beaches, trails leading to the beaches, in the North, South, and East parking lots and in other high-traffic areas.
Here is a map of the impacted areas at Discovery Park.
King County will monitor air quality throughout the process.
In 2011, King County installed West Point’s cogeneration system, which converts gas from the sewage treatment process into a source of heat and energy for the plant. Along with providing heat for the West Point Treatment Plant, some of the gas is converted to electricity and sold to Seattle City Light.
