FROM: James D. Herberg, General Manager
Originator: Kathy Millea, Director of Engineering
SUBJECT:
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A-SIDE PRIMARY CLARIFIERS REPLACEMENT AT PLANT NO. 2, CONTRACT NO. P2-98A
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION: Recommend to the Board of Directors to:
A. Receive and file Bid Tabulation and Recommendation for A-Side Primary Clarifiers Replacement at Plant No. 2, Project No. P2-98A;
B. Award a Construction Contract to PCL Construction, Inc. for A-Side Primary Clarifiers Replacement at Plant No. 2, Contract No. P2-98A, for an amount not to exceed $111,405,880; and
C. Approve a contingency of $6,684,353 (6%).
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BACKGROUND
The primary treatment process removes solids from screened wastewater upstream of biological treatment and is an essential part of the wastewater treatment process. This treatment is done in large concrete structures called primary clarifiers. The wastewater in the primary clarifiers emits detectable concentrations of hydrogen sulfide and other odorants, so the Orange County Sanitation District (OC San) covers all primary clarifiers and ventilates them to a foul air treatment system. The hydrogen sulfide in the foul air also creates conditions corrosive to both concrete and steel.
The primary treatment facilities at Plant No. 2 consist of fourteen 140-foot diameter circular clarifiers built between 1960 and 1985 with associated piping, distribution structures, sludge pumping, odor control, and power distribution. The clarifiers are divided into three groups referred to as the A-Side, consisting of four clarifiers, and the B-Side and C-Side, consisting of five clarifiers each. Each clarifier is covered with an aluminum geodesic dome connected to a foul air odor control system. The North Scrubber Complex treats foul air from the B-Side and C-Side clarifiers, and the South Scrubber Complex treats the foul air from the A-Side clarifiers.
RELEVANT STANDARDS
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