City of Caldwell WAS Thickening Improvements DAFT Building Construction

The City of Caldwell, Idaho will receive bids for City of Caldwell WAS Thickening Improvements DAFT Building Construction . Bids are currently due on or before 4:00 pm , on Tuesday, May 26, 2026 . Prospective bidders are requested to attend a non-mandatory pre-bid meeting at 1:00 PM on Wednesday, May 6th, 2026 at the City of Caldwell Wastewater Treatment Plant, 208 Johnson Ln, Caldwell, ID 83605.

This project focuses on the construction and commissioning of DAFT Room No. 2 (approximately 1000 sq. ft., roughly 18 ft. tall), including supporting site, structural, and process improvements. Work begins with selective demolition and excavation to prepare the site for new foundations, followed by construction of the DAFT tank foundation, floor slab, and installation of a fully welded, watertight DAFT tank. Subgrade piping and structural penetrations will be completed early to ensure seamless integration with existing facilities and future above‑grade systems.

Subsequent phases include yard improvements such as roadway realignment, paving, grading, sidewalks, and protective bollards, along with full completion of the DAFT Room No. 2 building enclosure. The project culminates in installation of the complete DAFT No. 2 treatment system, including new sludge pumps, process piping, valves, electrical and control systems, HVAC, plumbing, and a new polymer dosing system. Additional process and utility upgrades will be completed within the Blower/Solids Handling Building. Overall, the project represents a comprehensive upgrade to treatment infrastructure and offers opportunities for qualified vendors with expertise in civil, structural, mechanical, and process systems to contribute to a critical, integrated facility improvement.

NOTE: The DAFT tank will be supplied by OVIVO, but will be installed/welded on site. This tank is expected to arrive Dec 2026-Jan 2027. The OVIVO equipment purchase has been executed by the Owner with an initial downpayment. The equipment purchase contract and remaining balance shall be assigned to the awarded general contractor.

The City of Caldwell Wastewater Treatment Plant (WWTP) treats the wastewater generated by the City of Caldwell, with a population of approximately 79,000. As growth continues across the city, the WWTP must continue efforts to upgrade the complex to meet capacity and regulatory compliance needs. This construction projects involves adding a second dissolved air flotation (DAF) clarifier, which will provide critical redundancy for thickening waste activated sludge prior to digestion. The additional DAF unit was identified as a key facility need in the City’s wastewater planning efforts. This project supports the City’s long term wastewater infrastructure reliability.