City of Santa Barbara,
El Estero Wastewater Treatment Plant Headworks Screening Replacement Project
- Multi-rake mechanical bar screens, each fabricated in five sections and installed vertically due to existing constraints.
- Screenings washer/compactors with mechanical agitators to improve screenings washing, reduce hauling volumes, and mitigate odors.
- State-of-the art, smart motor control center to support new and existing equipment.
- Successfully undertaken multiple bypass pumping operations of raw sewage and plant drain flows entering into the headworks facility.
The City of Santa Barbara (City) El Estero Headworks Screening Replacement project retrofitted an existing headworks with modern equipment and upgraded existing electrical infrastructure, while improving system reliability, reducing maintenance, and implementing process automation. The existing screening and screenings handling system at the 11-mgd El Estero Wastewater Treatment Plant was replaced in its entirety. The new system, which consists of two mechanical bar screens, eight sluice gates and motor operators, one shaftless screw conveyor, and two screenings washer/compactors, significantly reduced the level of operation and maintenance required for the plant staff. The new screenings washer/compactor achieved a high degree of screenings washing and, as a result, significantly reduced odor and improved the handling and hauling of the screenings. The project also replaced an existing motor control center that served the Headworks, the Influent Pump Station, and other critical processes at the plant.
Completing the work required several significant process interruptions in scale and duration. Keeping the plant in service throughout the construction and minimizing the impact of the shutdowns were of paramount importance. Carollo collaborated with staff during design through a series of workshops and developed a detailed construction sequencing plan that provided specific work restrictions, milestones, and schedule constraints for the contractor. The plan included use of temporary bypass pumps of raw influent and plant drain, sequential replacement of parallel process equipment, and requirements for efficient work completion by combining shutdowns. The plan was incorporated into the contract documents to guide the contractor in bidding and construction. The bid results were highly favorable as the difference between the two lowest bids was less than 0.2 percent.