CITY COUNCIL AGENDA ITEM
Memo Date: February 2, 2024
Agenda Date: March 26, 2024
Prepared By: James Mitchell, Water Treatment Manager
Through: John A. Walsh, P.E., Utilities Director
Requested Action:
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To Approve Amendment #1 to the Multi-year Task Order 2023-33 with Jacobs Engineering, Inc. (Jacobs) to provide Engineering services for the design, permitting, and bidding of the project to replace the Carbon Dioxide Storage and Feed System at the Dyal Water Treatment Plant (WS23BR); To Approve a Resolution Amending the FY2024 Budget, BAF# 24-053-T and Allow for the City Manager to Finalize the Account Numbers for the Replacement of the Fluoride Bulk Storage Tank (WS23FT).
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BACKGROUND:
Carbon dioxide is used at the Dyal Water Treatment Plant to lower and optimize the pH of the treated water prior to filter operations. The existing recarbonization equipment that is used consists of two 70-ton liquid carbon dioxide storage tanks with associated refrigeration, vaporizer, and diffuser systems. This system was constructed over a period of time with some portions original to the plant and some portions installed in the 1990s. The entirety of the equipment has reached its projected useful life and requires replacement.
During early preliminary design for the replacement of the carbon dioxide system, discussions with City staff regarding the construction sequencing for replacement of the existing carbon dioxide storage tanks led to considering the relocation of the carbon dioxide tanks to an adjacent location to keep both existing tanks in operation during construction and reduce the risk of losing the ability to feed carbon dioxide should an issue arise with the existing carbon dioxide tanks. With space at the plant limited, consideration was given to changing from horizontal carbon dioxide storage tanks to vertical storage tanks; however, this option did not provide much benefit with regards to space.
City staff and Jacobs discussed the challen...
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