Hyperion ESD Egg-Shaped Digesters

Hyperion ESD Egg-Shaped Digesters

Hyperion ESD Egg-Shaped Digesters

Industry served
Playa Del Rey, California, USA

Scope of Work

Project Management, Structural Design, Dynamic and Stress Analysis, Detailed Engineering, Procurement, Subcontract and Construction Management, Field Erection, Nondestructive Examination, Hydrostatic Testing


The City of Los Angeles, California, decided to provide secondary treatment of all wastewater discharged into its system. Meeting this ambitious objective required significant expansion of the Hyperion Treatment Plant in Playa Del Rey, California. As part of the project, CB&I received a contract for the design and construction of 20 egg-shaped anaerobic digesters (ESD™).

Egg-shaped digesters were chosen because of space limitations at the plant. Conventional anaerobic digesters with comparable capacity would have required twice as much land area.

Each of the 20 digesters is up to 83.5 feet in diameter, reaches 110.5 feet high and has an operating capacity of 2.5 million gallons. The vessel design required an internal gas pressure range of -6 to +20 inches of water column. To verify the design was adequate for the specified earthquake loading, CB&I performed a response spectra analysis.

Steel construction was chosen over concrete, resulting in lower cost and faster construction. CB&I performed automatic welding on many of the butt welds, which optimized the project schedule, while working in a very congested installation site.

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