The Western Virginia Water Authority (Authority) and Roanoke Gas Company (Roanoke Gas) have entered into a cooperative agreement to produce commercial quality renewable natural gas, or RNG, from biogas produced at the Roanoke Regional Water Pollution Control Plant.
At the Roanoke Regional Water Pollution Control Plant, an average of 37-million gallons of wastewater is treated daily from all jurisdictions in the Roanoke Valley. The Roanoke Regional Water Pollution Control Plant (WPCP) is an advanced treatment wastewater facility currently permitted to treat 55 million Gallons per Day (MGD) of wastewater per day with an average daily flow of 37 MGD. Sanitary sewer from businesses and residences in the Cities of Roanoke and Salem, the Counties of Roanoke and Botetourt and the Town of Vinton are fully treated at this regional facility. The WPCP has a history of utilizing forward thinking approaches throughout the life of the facility and was one of the first plants in the Country to attempt to beneficially utilize the digester gas produced in the solid’s treatment process.
Multiple treatment technologies were evaluated and the selected company, Unison Solutions, is a recognized industry leader in biogas treatment technology. Unison has a demonstrated history of success providing the treatment technology for similar gas treatment projects as this market emerges within the United States.
“We are thrilled to have the opportunity to partner with the Western Virginia Water Authority on such an impactful and needed project,” stated Paul Nester, president, and CEO of Roanoke Gas Company. “Our shared desires to improve the environment, utilize the best technology and most importantly, serve this community, have spurred approximately $16.5 million dollars of combined investment and added a much-needed source of safe, clean natural gas.”
The initial treatment of the biogas includes a pretreatment step which removes hydrogen sulfide, moisture, siloxanes, and VOCs. A membrane filter system will remove the carbon dioxide (CO2) and help polish the gas to commercial quality. In the design of this installation, a third stage of membranes, located inside the digester gas conditioning system, will further treat all the produced tail gas and recover residual methane. Compression is required to boost the digester gas to pipeline pressure at the interconnect facility.