FROM: James D. Herberg, General Manager
Originator: Kathy Millea, 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:
A. Approve a Professional Design Services Agreement with CDM Smith, Inc. to provide engineering services for Digesters Rehabilitation at Plant No. 2, Project No. P2-137, for an amount not to exceed $2,700,000; and
B. Approve a contingency of $270,000 (10%).
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BACKGROUND
Sludge is a byproduct of wastewater treatment that requires further processing to reduce pathogens and organic content so the remaining material can be beneficially reused in compliance with state and federal requirements.
The Orange County Sanitation District (OC San) has 18 anaerobic digesters at Plant No. 2 that were built from 1959 through 1979, and they 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.
Based on OC San's 2017 Biosolids Master Plan, OC San is implementing a program to upgrade the digestion process using a new Temperature Phased Anaerobic Digestion (TPAD) process. This includes building some new digesters, rehabilitation of some existing digesters, and demolition of some existing digesters.
The program consists of four sequential construction projects finishing in 2040. The first project, TPAD Digester Facility at Plant No. 2, Project No. P2-128, is in design with construction anticipated to start in 2025.
RELEVANT STANDARDS
* Comply with California Government Code ?4526: Select the "best qualified firm" and "negotiate fair and equitable fees"
* 24/7/365 treatment plant reliability
* Safe, beneficial reuse of Biosolids
PROBLEM
The anaerobic digesters at Plant No. 2 have been in service for 40 to 60 years and need to be rehabilitated to per...
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