Designates projects that provide innovative and sustainable solutions for our clients

Tetra Tech’s subsidiary, BioCNG, LLC is the design-build firm that installed its BioCNG™ biogas conditioning system and gas pipeline for the Persigo Wastewater Treatment Plant (WWTP) in Mesa County, Colorado. BioCNG is the co-inventor of the patent-pending BioCNG system.

The Persigo WWTP is jointly owned by the City of Grand Junction and Mesa County, Colorado. BioCNG engineered the system and provided permitting, construction management, and system commissioning and startup support. Additional work included design and installation of an option to preferentially use BioCNG biogas in the WWTP digester boiler instead of natural gas, thereby saving on treatment plant operating costs.

The new BioCNG system will produce up to 500 gallons of gasoline equivalent per day from the WWTP digester gas, which will be piped about 6 miles to Grand Junction’s existing compressed natural gas (CNG) fueling station. The BioCNG will fuel a fleet of buses owned by Grand Valley Transit (GVT) and fueled at the City of Grand Junction facility, as well as for city refuse trucks, street sweepers, and general utility pickups. The City of Grand Junction and GVT continue to purchase additional CNG vehicles to increase the overall CNG fleet.

The client will experience immediate savings from using lower-cost compressed natural gas versus higher-priced diesel fuel. Overall fuel savings are expected to offset the cost of the project within a decade. The Persigo WWTP project is the first of its kind in the state.


  • Recipient of a 2015 Natural Gas Vehicles for America Industry Achievement Award