FROM: James D. Herberg, General Manager
Originator: Kathy Millea, Director of Engineering
SUBJECT:
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PRIMARY SEDIMENTATION BASINS NO. 6-31 RELIABILITY IMPROVEMENTS AT PLANT NO. 1, PROJECT NO. P1-133
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION: Recommend to the Board of Directors to:
A. Approve a Professional Design Services Agreement with Carollo Engineers, Inc. to provide engineering services for Primary Sedimentation Basins No. 6-31 Reliability Improvements at Plant No. 1, Project No. P1-133, for an amount not to exceed $1,219,667; and
B. Approve a contingency of $121,967 (10%).
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BACKGROUND
Primary clarification is used to cost-effectively reduce suspended solids to the secondary treatment processes. Primary clarification occurs in structures referred to as either primary clarifiers or primary sedimentation basins.
Plant No. 1 includes two sets of primary clarifiers; a set of twenty-six rectangular clarifiers and a much older set of three circular clarifiers. The circular clarifiers are nearing the end of their useful life and are scheduled to be replaced under Primary Clarifiers Replacements and Improvements at Plant No. 1, Project No. P1-126. That project will require at least three years to construct.
During replacement of the circular clarifiers, only the rectangular clarifiers will be available. Due to the reduced treatment capacity during this time, the reliability of the rectangular clarifiers is paramount to maintain the required Level of Service.
RELEVANT STANDARDS
* 24/7/365 treatment plant reliability
* Meet volume and water quality needs for the GWRS
* Comply with Government Code Section 4526: Select the "best qualified firm" and "negotiate fair and equitable fees"
PROBLEM
The reliability of the rectangular clarifiers is limited by aging infrastructure including Influent launders that are structurally unsound, limitations in sludge pumping capability, and accumulation of wa...
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