June 19, 2020. Tetra Tech and CGRS, Inc. are partnering on the City of Boulder’s innovative Biogas Use Enhancement Project, a biogas-to-renewable natural gas (RNG) conditioning system under construction at the city’s Water Resource Recovery Facility (WRRF). Biogas produced from wastewater digesters will be converted into renewable natural gas (RNG) for vehicle fuel, delivered to community partners after injection into the Public Service Company of Colorado (PSCo) pipeline. Construction began in January and is scheduled for completion this summer.

Tetra Tech, a leading provider of high-end consulting and engineering services, is providing engineering, procurement and construction (EPC) services to the City of Boulder. Fort Collins, Colorado-based CGRS is the general contractor and design-build partner, overseeing and performing the majority of on-site construction work.

The project will replace the WRRF’s cogeneration system, which is at the end of its useful service life, with a new digester gas upgrading system. Western Disposal has agreed to purchase the city’s RNG to fuel a portion of its vehicle fleet, approximately 31 trucks. The project will also enable the City to take advantage of revenues available to renewable fuel producers under the EPA’s Renewable Fuel Standard, driving a projected return on investment in the next 10 to 15 years.

“The Biogas Use Enhancement Project is the next logical step toward making the WRRF more environmentally sustainable as well as economically viable,” says Chris Douville, Wastewater Treatment Manager for the City of Boulder. “We’re pleased to realize the positive impact on the community’s climate goals through production and use of RNG as vehicle fuel, as well as the city’s financial ability to support other renewable energy and sustainability projects in the future through sale of RNG.”

The work includes installing a BioCNG™ gas conditioning system, demolishing the existing cogeneration engines and heat recovery systems, installing one new boiler, and upgrading the hydronic system used to heat the digesters and other buildings.