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 challenges of the carbon dioxide bulk tank replacement and developed a solution which reduces the risk during the tank replacement and accomplishes another planned renewal project simultaneously. The fluoride chemical feed system at the Dyal WTP requires the demolition and replacement of the bulk storage tank and piping, repair and recoating of the containment structure and piping, addition of bulk tank concrete pad and other miscellaneous work. This system is located adjacent to the carbon dioxide bulk storage tanks. The location of the existing fluoride system was identified as a good location for the new carbon dioxide bulk storage tanks; however, the fluoride system would need to be relocated. The benefits of relocating the fluoride tank were identified as:
• The existing system is scheduled to undergo a major replacement in the current fiscal year.
• The fluoride system injection points are located before the groundwater treatment plant reactor clarifiers and do not inject into the surface water plant or ASR process stream. This configuration complicates chemical dosing when the surface water plant and ASR recovery is operating. Relocating the fluoride system closer to the finished water storage tanks and high service pump stations, similar to other finished water dosing such as chlorine and ammonia, allows better control of fluoride dosing into the finished water.
• This configuration eliminates safety concerns with the existing fluoride system containment area which requires confined space entry to operate or maintain equipment.
A location for a new fluoride system was identified near the finished water facilities. This solution was acceptable to City staff and was requested to be included in this project scope of work.
The Carbon Dioxide Storage and Feed System project (WS23BR) and the Fluoride Bulk Storage Tank Replacement project (WS23FT) are both budgeted for FY24. Due to the proposed scope of work outlined in this amendment, the funds budgeted for both projects will be combined into one project (WS23BR). Therefore, a project transfer is required (see attached BAF# 24-053-T).
Staff recommends the approval of the proposed Amendment #1 to the Multi-year Task Order 2023-33 with Jacobs Engineering, Inc. (Jacobs).
STRATEGIC PLAN CONNECTION:
N/A
BUDGETARY IMPACT:
Budgeted Yes; project transfer required
If not budgeted, is amendment/transfer attached? N/A
Amount Requested $240,000.00
Transfer From Account Number: 424-4020-536.64-00
Transfer From Account Name: Machinery & Equipment
Transfer Amount: ($240,000.00)
Project Number: WS23FT
Transfer To Account Number: TBD
Transfer To Account Name: Infrastructure
Transfer Amount: $240,000.00
Project Number: WS23BR
PREVIOUS ACTION:
On September 12, 2023, City Council approved a 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).
RECOMMENDED MOTION:
Recommendation
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).