Klickitat Public Utility District RNG Project

Opportunity

Klickitat Public Utility District (KPUD) is a long-term client that has teamed with Montrose to manage several site upgrades related to their 2010 Landfill Gas (LFG) Turbine Cogeneration Project at the Roosevelt Regional Municipal Solid Waste Landfill located in Roosevelt, Washington. In 2016, KPUD partnered with Montrose engineers in their Renewal Natural Gas (RNG) Project to look at alternative uses for LFG.

Challenge

The Montrose Biogas project team worked with KPUD, beginning at initial project conception, to detail out how to transition the plant from a turbine cogeneration project to a direct pipeline RNG plant. The Montrose team was subsequently selected to lead detailed design and engineering, technology selection, construction oversight, and plant commissioning for the project. Throughout the process, the primary challenge centered around how to efficiently and cost-effectively clean and purify the landfill gas in order to meet the required pipeline tariff specifications.

Solution

On November 1, 2018 KPUD and the Montrose team successfully commissioned and started up the unique, Montrose-led RNG plant. The system features a combination of a cryogenic Nitrogen Rejection Unit (NRU) and Iron Chelate system that represents the first such combination in the United States for the treatment of H₂S.  Other components of the process include dehydration, compression and removal of H₂S, siloxanes, CO₂, O₂ and N₂. The resulting gas quality at the plant outlet is in excess of 990 BTU/SCF, meeting any natural gas tariff in the United States.  The system has been converting 8,000 standard cubic feet per minute (SCFM) of landfill gas to 6,000 MMBTU of RNG per day, which is then injected into an 800 psig pipeline approximately three miles from the facility.  The Montrose team was on site throughout the entire process and was instrumental in the successful completion and startup of this innovative approach and unique deployment of technology in the biogas industry.