FROM: James D. Herberg, General Manager
Originator: Kathy Millea, Director of Engineering
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TPAD DIGESTER FACILITY AT PLANT NO. 2, PROJECT NO. P2-128
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION:
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BACKGROUND
Sludge is a byproduct of wastewater treatment that requires further processing to reduce pathogens and volatile organic content so the remaining biosolids material can be beneficially reused in compliance with state and federal requirements. The Orange County Sanitation District (OC San) uses anaerobic digesters at both plants to stabilize sludge prior to dewatering. Anaerobic digesters are large enclosed concrete structures that require pumping, mixing, heating, and gas handling systems. Anaerobic digesters also generate methane gas used to produce power and heat.
OC San has 18 digesters at Plant No. 2 that were built from 1959 through 1979. A comprehensive Biosolids Master Plan completed in 2017 recommended upgrading the existing digester complex by adding Temperature Phased Anaerobic Digestion (TPAD) facilities.
TPAD Digester Facility at Plant No. 2, Project No. P2-128, is the first of four sequential projects planned to ultimately replace the entire digester complex by 2040. The Preliminary Design Report for this $455 million project was completed in January 2022.
Staff will present an update on the project and decisions used to control costs.
RELEVANT STANDARDS
• 24/7/365 treatment plant reliability
• Safe, beneficial reuse of Biosolids
• Use all practical and effective means for resource recovery
ATTACHMENT
The following attachment(s) may be viewed on-line at the OC San website (www.ocsan.gov) with the complete agenda package:
• Presentation
JM:jw