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Hyperion ESD™ Egg-Shaped Digesters

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, APTIM received a contract for the design and construction of 20 anaerobic Egg-Shaped Digesters. ESDs 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, APTIM performed a response spectra analysis. Steel construction was chosen over concrete, resulting in lower cost and faster construction. APTIM performed automatic welding on many of the butt welds, which optimized the project schedule while working in a very congested installation site.

Contracting Entity: The City of Los Angeles