Biogas and Biosolids Evaluation: Digester 1 Cleaning

The City of San Mateo is requesting sealed bids for cleaning and interior surface preparation of an existing anaerobic digester (City Project No. 46T090), with bids due July 16, 2026 at 2:00 p.m. Bidders must hold California Class A Contractor licenses and be registered with the Department of Industrial Relations under Labor Code Section 1725.5.

The scope includes mobilization and demobilization, removal and offsite disposal of all digester contents, high-pressure washing of all interior surfaces, design and installation of interior scaffolding for confined-space access, and abrasive blasting of all interior surfaces. An optional bid item covers screening and transfer of digester contents to Digester 2 down to approximately 15 feet above the cone bottom. Contractors may provide temporary on-site dewatering systems to reduce liquid volume prior to offsite disposal. Subsequent repair and coating will be performed under a separate contract.

The estimated construction cost is $1,100,000, provided for reference only. The contract duration is 130 working days from the Notice to Proceed. All work is subject to California prevailing wage requirements as determined by the Department of Industrial Relations and must comply with non-discrimination requirements under federal and state law.

Bid bonds, cashier's checks, or certified checks in an amount not less than ten percent of the aggregate bid amount must accompany all bids. A five percent retention will be held for 35 days after the Notice of Completion is recorded; contractors may substitute securities or request direct payment to an escrow agent at their expense. The City reserves the right to reject any or all bids and to award the contract to the lowest responsible bidder. All addenda issued during the bidding period must be acknowledged in the bid submission.

Plans and specifications are available through Barker Blue via the City of San Mateo Public Works Bidding Web Portal. Questions should be directed to Jennifer Lam, Project Manager, at jlam@cityofsanmateo.org.