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.
In 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.
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.