San Diego Residents Will Soon Be Drinking Desalinated Seawater

By Eliza Strickland | May 15, 2009 4:33 pm

water dropBefore the end of the year, the backhoes are expected to dig into the dirt on a patch of coastal land in southern California, as construction begins on a massive plant that will draw fresh water from the salty sea. California regulators have given the green light for the construction of the largest desalination plant in the Western Hemisphere in Carlsbad, California, overriding environmental protests.

Some green groups are appealing the plant’s approval to a state water board, but officials with Poseidon Resources, the development company, seem confident that construction will begin on schedule. When the plant cranks up to high gear, engineers expect it to produce enough fresh water for 110,000 households in the San Diego area.

Advocates of desalination tout its potential for limiting strain on scarce water supplies, and easing the environmental consequences of diverting freshwater from rivers and streams and pumping it long distances to urban centers. But critics cite major environmental drawbacks — namely the harm to marine life from intake pipes that suck water into desalination plants and from the highly concentrated brine byproduct that gets discharged back into the ocean [Reuters]. In the environmental agreement hammered out between Poseidon and the San Diego Regional Water Quality Control Board, the company will create 55 acres of wetlands as breeding grounds for fish to offset those killed by the plant’s operations. The company has also pledged to keep brine concentrations below toxic levels.

The plant will filter 100 million gallons of seawater daily, taking salt out by filtering it through fine membranes, a process called reverse osmosis. If construction proceeds as scheduled, it will produce 50 million gallons of drinking water by 2011. The plant would provide water to nine municipal water agencies in northern San Diego County, filling 10 percent of the county’s drinking water needs. Its capacity makes it one of the biggest outside the Middle East [The New York Times].

The $320 million project is the first desalination plant to make it through the regulatory process in California, but if it proves effective, lucrative, and environmentally benign many more will likely follow. Other projects are being considered along the California coast, from Marin County just north of San Francisco to Santa Cruz, Monterey, Long Beach and Huntington Beach [The New York Times].

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Image: flickr / D Sharon Pruitt

CATEGORIZED UNDER: Environment, Technology
  • Nick

    Okay, here’s what needs to be done – in Neal Stephenson’s The Diamond Age (yea, scifi book, bear with me) they needed molecular sources for their nanotech projects. They pulled up seawater. Through an ultra-fine capillary network. So giant chunks of sealife couldn’t get pulled up, and smaller ones wouldn’t be trapped because the inlet pressure would be so faint and distributed.

    On this blog a while back, there was a story about a scientist who replicated tree’s amazing ability to move water skywards WITHOUT ENERGY. Mass produce that, use it to pull in seawater – you don’t hurt the life, you don’t need energy to run the intake, and the inlets may be so small that less filtering would be needed.

    You could make this thing into a tower – have the water drawn up however many feet in the air, then dropped into a giant water silo to provide the pressure at the bottom to run the reverse osmosis system (you need a lot of pressure for that) – assuming the capillary network wasn’t capable of filtering the water to the point this was un-necessary. Or you could do distillation – there is a LOT of sun in San Diego – it’s usually about 80 degrees on the coast, year round. Combine with a solar thermal plant – heat the water to steam, have it run a turbine for energy, capture the steam into a distillation chamber (have to make sure the water doesn’t get hydrocarbonified from lubrication in the turbine, perhaps a tesla turbine could be used?) and then it’s pure water, ready to go, after having generated electricity.

    Maybe version 2.0. 😀 But I’m all about efficiency

  • Joe

    The problem with ocean desal is the extreme amount of energy it uses. In Catalina, for instance, the desal plant accounts for 25% of all water supply but uses 70 percent of the island’s energy! That’s directly from SoCal Edison.

    Also desal plants such as the one in Carlsbad and the one proposed for Huntington Beach both will be co-joined to aging power plants in order to use their outdated cooling systems, which they will use to suck in ocean water. The desal plant planned for Huntington Beach will need to suck in 300 million gallons of water a day to meet their projections. All the marine life, fish, etc, sucked into this system is killed.

    For more info about the Huntington Beach project, go here

  • Joe
  • Mike

    If there were strict laws passed on water usage, maybe they would not need these things in the first place. Southern Californians use WAY too much water on large, sprawling lawns and trillions of tons (plant matter) of non native, lush species filling people’s yards. My neighborhood in LA is lot after lot of lush green lawns and sculptured tropical headges, etc. I have been slowly replacing everything with native and desert plants.

    All that work and energy to supply 10% of the houses? What happens when millions of houses might need this water?

    Most of the population is clueless on where their water comes from and how not to waste it. Laws need to be enacted and enforced – which I predict will happen at some point anyway when the situation gets dire. LA loses enough water from it’s river after a big rain that would last the city for months…maybe they should look at ways to capture and treat it – like in underground reservoirs. Hong Kong has such a system to catch Typhoon runoff.

    Laws? – are these really so “out there”?

    Mandatory native plants in all new homes, incentives, assistance to convert all existing homes…
    Roof rain water colleciton tanks built into the foundations of all new homes, used for lawns and pools, tax incentives to install in older homes (it would boom a whole new industry and many jobs).

  • Joe2

    There are laws on desal intakes — the laws are not being enfoced. The law (Porter-Cologne Act) requires new industrial facilities (desal) to use the best site, design and technology to avoid the intake of marine life. AVOID THE INTAKE!! It doesn’t say it’s OK to kill every living organism floating in the water column near the intake and then try to replace it somewhere else.
    I agree 100% that we can’t go on wasting water on irrigation for ornamental vegetation in our front yards. Approximately 50% of all our residential water consumption is growing grass. And, approximately 70% of the polluted runoff from residential neighborhoods is from irrigation and the pollutants we use to grow turf grass. Gimme a break!
    We also discharge freshwater from our wastewater treatment facilities that could be purified for drinking using the same technology as ocean desal — but at a fraction of the cost and energy demand.
    Finally, like you said, we have unnnecessarily over-paved our natural water courses — drying up our local groundwater in much of southern California.
    To an outsider it would look insane: we do everything in our power to force water off the land, and then pump it back out of the ocean to remove the salt (at enormoous costs both to our pocketbook and our environment). INSANE!!

  • Mathew

    For all of you folks complaining about the amount of vegetation that folks grow in their yards, ornamental or not, remember that trees and plants are currently one of the cheapest and most economical ways of removing CO2 from the atmosphere.

    It is estimated that about 300 trees will absorb enough Co2 from the atmosphere to account for the same amount that a person will produce in their lifetime, including home energy use, travel, etc.

    All this vegetation that you’re so worried about will actually more than offset the carbon effect of all the energy it takes to produce the water necessary to keep them alive, having a net positive effect on the environment.

  • Lange

    First of all, San Diego will NOT be the first metro area of the US to use desalinated waer. That dubious title belongs to Tampa, Florida.

    I say “dubious” because the desal plant in Tampa is plagued with problems. Years after it was to go into full service, the plant still does not work quite right.

    It’s probable that Tampa’s plant has problems due to design as well as construction deficiencies. There appears to be a fair amount of corruption in the original contracting for this plant as well as its actual construction and operation. Hard to say if that really did affect the plant, but given many other disastrous local contracting projects, it is certainly a possible factor.

    Desal is not necessarily a bad solution to water shortages, or to problems of water quality. There are some interesting reverse-osmosis water treatment plant designs that would be extremely useful in areas with badly-polluted water (and remember lots of pollution is natural) or where treatment of water to eliminate disease vectors (parasties, etc.) is otherwise impractical. In central California, where saltwater intrusion is a significant factor in groundwater, this kind of process might be extremely useful.

    Controlling population through restrictions on water or sewer capacities has already been attemped, and it plain does not work. I cite the case of Goleta, which 40 years ago refused connection to the California Water Project, and later used sewer capacity as a means of limiting construction permits. It simply failed, and later Goleta paid a ton of money to access water supplies.

    Conservation and wise water use is effective in making existing water resources serve the intended population base during periods of stress such as drought. Conservation is ineffective as a means of replacing lost supplies or expanded demands.

    Saudi Arabia is the largest example of generating fresh water from desalination, and it is an expensive but effective solution.

    Ultimately, no matter what is done, there comes a saturation point at which no amount of effort will supply demands for not only water but also food, living space, and clean air among other things. If we are foolish enough to breed so profligately that we reach this point, then the Malthusian principle will take over and people will either move or die off until a new point of stability is reached. That’s a very nasty, cold assessment and not especially the way we should let events unfold. However, intervention in population movement and growth involves so many other rather nasty ideas that at least for now a modern, progressive, democratic society is unable to take up such an agenda.

    So build the plant and charge a LOT for the water. That will help limit consumption and the rate of growth encouraged by it.

    By the way – I earend several major awards for promotion of water conservation and wise water use in Southern California over the past 35 years. I still think that far too little is done in this respect, partly out of sensitivity to interfering with the happy, stupid comfort a bunch of people have come to expect without any thought about it.

  • Eliza Strickland


    Thanks for your correction. The headline got changed in the editing process, but I’ve now changed it again to reflect the fact that, as you say, Tampa has tried out this technology already.

  • Mike E

    Most homes and businesses have water heaters and coffee makers. Desalination is basically the same technology. Is it a problem if people shower with sea water, flush with sea water, wash their clothes and dishes with sea water, and fill their swimming pools with sea water? Just asking.

    A home or personal desalination appliance could be set to run at night when electricity is cheap. A solar appliance would use little or no electricity.

    Some businesses would be impacted, namely, restaurants, cafeterias, hotels and hospitals. Public drinking fountains would have to be modified. But if people can live with digital TV, then maybe they can adapt to unlimited amounts of cheap and plentiful sea water.

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