The City of Yakima's (City's) Wastewater Treatment Plant operates and maintains three hot water boilers to provide the heat that is required for the wastewater and biosolids treatment processes. The treatment plant reduces boiler fuel costs by recovering the biogas that is produced from the treatment processes; using the recovered biogas as the primary fuel in the boilers.
In recent years, plant staff have documented significant and accelerated deterioration of boiler components that is attributable to the condition of the recovered biogas. A 2018 Digester Gas System and Boiler Corrosion Study by Gray & Osborne, Inc. concluded that excessive moisture in the biogas was responsible for the boiler deterioration and recommended installation of a biogas drying system to remove the excess moisture.
City Project No. WF2484 was established for the construction of a biogas drying system to remove the excess moisture. The City utilized the procedure established by the State of Washington for competitively bidding projects. Two contractors submitted bids, with Pease and Sons, Inc. submitting the lowest bid of $395,490.48. See attached contract.
The project is funded by Wastewater Facility Capital Fund 478.
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