FROM: Robert Thompson, General Manager
Originator: Mike Dorman, Director of Engineering
SUBJECT:
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DIGESTERS REHABILITATION AT PLANT NO. 2, PROJECT NO. P2-137
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION: Recommend to the Board of Directors to:
Approve a Contingency Increase of $1,296,000 (48%) to the existing Professional Design Services Contract with CDM Smith, Inc., for the Digesters Rehabilitation at Plant No. 2, Project No. P2-137, for a total contingency of $1,566,000 (58%).
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BACKGROUND
The Orange County Sanitation District (OC San) has 18 anaerobic digesters at Plant No. 2 that were built from 1959 through 1979 and are used to convert sludge to biosolids and biogas for reuse. Anaerobic digesters are large enclosed concrete structures with pumping, mixing, heating, and gas handling systems. The Digesters Rehabilitation at Plant No. 2, Project No. P2-137, is required to extend the life of the digester complex at Plant No. 2. The project will repair the digester domes, walls, and bridges, improve miscellaneous safety related items, and replace electrical motor control centers that are obsolete.
RELEVANT STANDARDS
• 24/7/365 treatment plant reliability
• Protect OC San assets
• Ensure the public’s money is wisely spent
PROBLEM
At the April 2024 Operations and Administrative Committee meetings, Board members were informed that the current Digester Replacement at Plant No. 2, Project No. P2-128, would be constructed in two phases to allow staff to continue to monitor the biosolids market, monitor legislation on chemicals of emerging concern, and research and track future technology concerning biosolids disposal. Due to this extended timeline, the existing digesters being rehabilitated under Project No. P2-137 need a more comprehensive rehabilitation to extend their service life to the year 2043.
PROPOSED SOLUTION
Approve a Contingency Increase to provide additional rehabilitation design services. Rehabilitation will be expanded to repair deficiencies in the cable trays, replace digester gas balance lines, replace digester view ports, and add access platforms to the flame arrestors.
TIMING CONCERNS
The digesters are nearing the end of their life, a delay to this project could result in premature failure and require digesters to be taken offline until an unscheduled repair can occur.
RAMIFICATIONS OF NOT TAKING ACTION
An additional project would be required to complete these additional rehabilitation elements. Creating a new project would result in additional soft costs for the design and construction. Until the work is complete, OC San Maintenance Staff would continue to use costly methods for access and maintenance.
PRIOR COMMITTEE/BOARD ACTIONS
March 2022 - Approved a Professional Design Services Agreement with CDM Smith, Inc. to provide engineering services for Digesters Rehabilitation at Plant No. 2, Project No. P2-137, for an amount not to exceed $2,700,000; and approved a contingency of $270,000 (10%).
ADDITIONAL INFORMATION
N/A
CEQA
The project is exempt from CEQA under the Class 1 categorical exemptions set forth in California Code of Regulations Section 15301. A Notice of Exemption was filed with the OC Clerk-Recorder March 28, 2022.
FINANCIAL CONSIDERATIONS
This request complies with the authority levels of OC San’s Purchasing Ordinance. This item has been budgeted (Budget FY 2024-25 and 2025-26, Section 8, Page 74, Digesters Rehabilitation at Plant No. 2, Project No. P2-137) will increase the project budget and will be funded from the CIP budget.
|
Date of Approval |
Contract Amount |
Contingency |
|
03/23/2022 |
$2,700,000 |
$ 270,000 (10%) |
|
11/20/2024 |
|
$1,296,000 (48%) |
ATTACHMENT
The following attachment(s) may be viewed on-line at the OC San website (www.ocsan.gov) with the complete agenda package:
• Presentation
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