FROM: James D. Herberg, General Manager
Originator: Kathy Millea, Director of Engineering
SUBJECT:
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RETURN ACTIVATED SLUDGE DISCHARGE PIPING REPLACEMENT AT ACTIVATED SLUDGE PLANT NO. 1, PROJECT NO. FE20-03
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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 Return Activated Sludge Discharge Piping Replacement at Activated Sludge Plant No. 1, Project No. FE20-03;
B. Award a Construction Contract to GSE Construction Company Inc. for Return Activated Sludge Discharge Piping Replacement at Activated Sludge Plant No. 1, Project No. FE20-03, for a total amount not to exceed $3,985,400; and
C. Approve a contingency of $398,540 (10%).
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BACKGROUND
The Orange County Sanitation District (OC San) has three biological secondary treatment facilities at Plant No. 1, one of which is the Activated Sludge-1 facility. This process removes suspended and dissolved organic material using microorganisms, enabling OC San to meet ocean discharge permit limits and the required influent quality for the Groundwater Replenishment System (GWRS). The facility consists of a blower building, aeration basins, secondary clarifiers, a return activated sludge (RAS) pump station, and various utilities. This critical facility was built in 1973, expanded in 1999, and partially rehabilitated in 2008.
OC San completed a condition assessment of the RAS discharge lines and determined that many of the RAS pipelines were at the end of their useful life. OC San completed Project No. P1-129 in 2020, which replaced sections of the RAS pipelines at the RAS Pump Station and sections within the aeration basins. During Project No. P1-129 construction, other sections of the RAS system were discovered to also need replacement, but the extent of the work was determined to be too large to add as a change order. This project will replace the remaining sec...
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