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. Rehabi...
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