In just a few short months, San Diego County will add desalination to its water portfolio when the Carlsbad Desalination Project comes online. Producing 50 million gallons of water per day, the Carlsbad facility will be the largest desalination plant in the western hemisphere and is a key milestone in drought-proofing San Diego's water supply.
"This project, when it comes on line in the fall of this year, will add 7 to 10 percent to our overall water supply here in San Diego County," said Bob Yamada, Director of Water Resources, San Diego County Water Authority. "Most importantly, the Carlsbad Desalination Project represents a new, local water supply for San Diego County," he added, "and it will more than double the amount of local water that we've been able to develop in this region since 1991."
As California weathers its fourth year of drought conditions, having a dependable, local source of water is integral for helping the region sustain itself through periodic dry cycles. Desalination is part of San Diego County's ultimate goal to "stitch together the components of a reliable water supply," said Yamada.
But the Carlsbad project was not without its hurdles. It was twelve years in the making, with six of those spent mired in California's permitting process. Construction began, at long last, in early 2013 and, according to Yamada, it's gone exceedingly well. The facility is expected to start up on time (maybe even a little early) and on budget.
There are a number of impressive aspects of the project, not the least of which is the reverse osmosis technology at the heart of the plant where 18,000 membranes are housed inside 2,200 pressure vessels. "When the seawater arrives at the plant it goes through pretreatment through a multimedia filter, then is treated with micronic filtration," explained Mark Lambert, CEO of IDE Americas, which designed the facility and supplied the process equipment. "Then it goes through this heart-pumping reverse osmosis facility." After that, it's treated in a finished water tank where alkalinity is added back into the water so that it tastes good.
Lambert noted that over the last decade, seawater reverse osmosis -- and desalination facilities in general -- have made great strides in energy efficiency, improving consumption by about 30 percent. In the case of the Carlsbad facility, he said, "there's an energy recovery system (ERS), which recovers a majority of the high pressure that has been imparted to the feed water and that energy is recovered on the incoming feed water side."
Further, the pumping system is extremely energy efficient. "This is a reverse osmosis facility of 14 trains," Lambert explained, "and traditionally each of those 14 trains would have been fitted with its own independent pump. However, in this concept called ‘the pressure center,' which is unique to IDE, we're able to feed all of the high pressure water using two pumps."
As construction of the plant nears completion, excitement about the highly anticipated commissioning is palpable. "Our friends in the entire desalination industry have been watching and supporting us throughout this 10 year process," said Lambert, "and here we are on the cusp of completion. It will be a proud moment for all of us."
Angela Godwin
Chief Editor, WaterWorld
