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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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Beneficial Reuse of Biogas (Methane)

The Columbia Boulevard Wastewater Treatment Plant generates on average 600 million cubic feet of digester gas (biogas) per year as a by-product of stabilizing wastewater solids using anaerobic digestion. Biogas is about 60% methane and is a renewable alternative to natural gas. The plant has implemented several technologies to reclaim biogas to produce heat and power for onsite operations and other facilities.


Co-generation facilityIn 2009, Environmental Services installed two 850 kilowatt GE/Jenbacher engine-generators with a total generating capacity of 1.7 megawatts. A pretreatment system removes hydrogen sulfide, siloxane and moisture to prepare the biogas to be used as fuel.

The plant recovers heat from water and engine exhaust to use in its anaerobic digesters. The engine-generators supply about 40 percent of the plant's electrical needs.

Industrial Sales

The treatment plant also compresses approximately 20% of its biogas and delivers it via pipeline to a nearby industrial facility to use for process heating. This has been a very successful partnership since 1986.

Renewable Natural Gas project

Building on its history of reusing biogas, Environmental Services embarked on a new project in 2017 to capture almost 100 percent of the methane from wastewater treatment and convert it into renewable natural gas (RNG). This new locally-produced renewable and cleaner fuel will be marketed to displace dirty diesel for medium and heavy-duty vehicles. Find out more.