As the sun sets over the Pacific the water glistens. Water filled with salt. How much? Peter MacLaggan, VP at Poseidon Water in Carlsbad, says 3.5% of the water in the Pacific Ocean is salt. And, when removed, MacLaggan says the Pacific can provide a drought-proof supply of water.
He stands proudly in the middle of a construction site where a huge desalination plant is rising from the ground. There will be sand-filtering, but the main tool for removing salt from the ocean water is reverse osmosis (RO). Some 15,000 tubes with semi permeable membranes to sift out impurities, salt and other dissolved solids.
For as long as I can remember I've wondered how can we have droughts in California and be next door to a massive ocean??!! According to the experts desalination is not cheap and not easier. MacLaggan says it has gotten easier with improvements in technology and a little less expensive.
At Carlsbad, the RO filters are about 4 feet long. Water goes through thousands of them. Two streams come out of each one. One stream is fresh water. The other is salty. It's actually twice as salty is when it went into the system. The fresh water is sent into the community and is piped into regional distribution centers. Salt is reduced in the brine and returned to the ocean.
The fresh water from this system will represent about 7 to 8% of the total amount. MacLaggan says in the future there will be lots of buckets or sources of water, but his – he says – will be the most reliable because it comes from the ocean and isn't dependent on snow packs or rainfall.
Conner Evert fought the Carlsbad Desalination Project and is still fighting these efforts. He says they use too much energy and cost too much for what comes from them. Nonetheless, in 2016, San Diego will have the largest desalination plant in the western hemisphere when the new plant starts to operate.