Carlsbad 50 MGD Seawater Desalination Plant

Butier Engineering, Inc. and GHD were selected to provide Owner's Engineer services for the construction of a 50 mgd seawater reverse osmosis desalination plant at the Encina Power Station (EPS) located in the City of Carlsbad, California. The scope also includes the construction of a one million gallon product water storage tank, and product pump station and pipeline system to deliver the drinking water produced by the Project to water utilities and municipalities in San Diego County.

The source water for the Carlsbad desalination plant will be collected from the existing cooling water discharge outfall canal of the EPS. The power plant intake withdraws cooling water from the Pacific Ocean via the Aqua Hedionda Lagoon. After passing through the intake structure trash racks and traveling screens, the collected cooling seawater is pumped through the condensers of the power plant generation units. The warm seawater is discharged from the EPS condensers into a common enclosed discharge channel, which conveys the plant discharge to the Pacific Ocean through a jetty. A portion of the EPS cooling seawater will be collected from the power plant discharge channel and will be pumped to the desalination plant, processed through a pretreatment system, and desalinated via seawater reverse osmosis. The concentrate from the desalination plant will be discharged into the existing cooling water discharge channel for mixing with the remaining EPS discharge prior to its ultimate disposal to the ocean. The drinking water will be delivered to Poseidon customers in San Diego County by a water conveyance system which consists of product water pipeline and several booster stations and other service structures.