FROM: James D. Herberg, General Manager
Originator: Kathy Millea, Director of Engineering
SUBJECT:
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LIQUID OXYGEN TANK A REPLACEMENT AT PLANT NO. 2 (FE21-07), SPECIFICATION NO. S-2022-1345BD
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION: Recommend to the Board of Directors to:
A. Approve a General Services Contract with J.R. Filanc Construction Company, Inc. to provide the Liquid Oxygen Tank A Replacement at Plant No. 2 (FE21-07), Specification No. S-2022-1345BD for a total amount not to exceed $2,608,007; and
B. Approve a contingency in the amount of $260,801 (10%).
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BACKGROUND
The first step in the activated sludge secondary treatment process at Plant No. 2 requires injection of liquid oxygen (LOX) into the reactors. The LOX is delivered by truck and stored in two 40,000-gallon pressurized vessels, Tank A and Tank B, which were installed in 1977.
RELEVANT STANDARDS
* Sustain 1, 5, 20-year planning horizons
* Maintain a proactive asset management program
* 24/7/365 treatment plant reliability
PROBLEM
Tank A ruptured in 2018 and has been out of service since then. Repair attempts have been unsuccessful. Having two working 40,000-gallon tanks provides back-up LOX storage. Relying on only one tank means more frequent LOX deliveries. The loss of Tank A storage makes the Orange County Sanitation District (OC San) vulnerable and reliant on more frequent LOX deliveries. Currently, LOX is being delivered every other day. If the deliveries were interrupted, OC San would lose secondary treatment capacity at the Plant No. 2 activated sludge facility. Since Tank A is not usable, a rented trailer mounted 9,000-gallon tank is currently on-site to serve in a back-up capacity. If Tank B becomes unavailable, this back-up tank will provide less than three days of oxygen at average flows. When the final expansion of the Groundwater Replenishment System (GWRS) goes online, more flow could be treated at the a...
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