AGENDA TITLE:
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Accept Improvements Under Contract for Aeration Diffusers System Replacement at White Slough Water Pollution Control Facility Project, and Adopt a Resolution Approving Change Order No. 3 and Ratifying City Manager Approval of Increased Expenses (PW)
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MEETING DATE:
November 5, 2025
PREPARED BY:
Public Works Director
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RECOMMENDED ACTION:
Accept improvements under contract for Aeration Diffusers System Replacement at White Slough Water Pollution Control Facility Project, and adopt a resolution approving Change Order No. 3 and ratifying City Manager approval of increased expenses.
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BACKGROUND INFORMATION:
There are six aeration basins measuring 30 feet wide, 135 feet long, and 18 feet deep at the White Slough Water Pollution Control Facility (WSWPCF). The basins are a part of the secondary treatment process that supply dissolved oxygen for the micro-organisms that work to reduce concentrations of nitrogen and ammonia in the wastewater.
The City's prior aeration diffuser system had presented increasingly difficult maintenance and operational challenges for WSWPCF operations staff since its installation in 2007. Council authorized Robertson-Bryan, Inc. (RBI), the project design consulting firm, to prepare a technical memo identifying appropriate replacement options for the aeration system design for replacement of the aeration system. In January 2021, RBI completed the technical memo, which recommends replacing the membrane diffuser panels with a system that utilizes an array of disk filters. This technology requires substantially less labor when performing maintenance operations and eliminates the need to employ a crane.
Specifications for this project were originally approved by Council on June 21, 2023. The project was advertised on August 12, 2023.
On October 18, 2023, Council awarded the contract for Aeration Diffusers System Replacement at the White Slough Water Pollution Control Facility, t...
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