Caldwell Solids Handling and Digestion Improvements
The City of Caldwell WWTP required improvements to its solids handling and digestion processes. Keller Associates provided preliminary design, final design, bidding, and construction administration of the Solids Handling and Digestion Improvements Project.
The $7 million project included two new digesters, a mixing system retrofit for an existing digester, a pipe gallery, and demolition of multiple digesters, a lab building and modifications to the waste gas system. Preliminary design also included evaluations of thickening redundancy, a primary solids waste and drain pump station, and the location for the future dewatering building. Electrical design and phasing were a critical component of the project to keep operations up and running while the old digester control building could be replaced. The project involved energy-saving measures, such as linear motion mixers. With the completion of this project, the City will have redundancy and capacity to reliably meet a Class B biosolids.