Thinking Big, Going Small?

(Originally posted on waterefficiency.net)

By Elizabeth Cutright
Editor
Water Efficiency

A few weeks back, a friend of mine asked my opinion on desalination, specifically a proposed desalination plant in his hometown of San Diego, CA. As he said in his message, “I am not sold on this being the answer or even one of the answers to solving southern California’s water problems.”
I responded that, at the moment, the “cons” still outweigh the “pros” when it comes to desalination as a solution for water scarcity. First off, there are the environmental factors to consider—specifically the intake apparatus (which tends to suck up innocent sea life along with gallons of salt water), and the brine discharge (which alters the salinity near the outtake valves). But just as important are the energy implications— desalination is energy-intensive, and that energy comes from fossil fuel—which means an increase of greenhouse gas emissions and, possibly, an exacerbation of current climate conditions (i.e. global warming). Finally, desalination is very expensive, especially when simple efficiency and conservation option can help you use the supply you have in a smarter, more streamlined fashion.

Of course, there’s always an exception to the rule.
A few years back, I wrote an article on the Long Beach Desalination Research and Demonstration Program, a facility designed to counteract the main drawbacks of large-scale desalination: energy consumption and environmental impact. As I stated in that article, facility opened in in September 2005 as a research and development project capable of processing 300,000 gallons of water per day. The Long Beach plant is 20–30% more energy efficient than traditional desalination; an efficiency achieved through the use of nano-filtration and specially designed filtration membranes. Additionally, development the Under Ocean Floor Seawater Intake and Discharge Demonstration System at the Long Beach facility eliminates the danger of sea life inadvertently being sucked into the pipes and killed. Finally, after water is flushed through the second set of membranes, the final output contains less than 500 milligrams of dissolved substances per liter of water, thereby complying with EPA drinking-water standards (and mitigating brine discharge).
The Long Beach project is a good example of the future of desalination—a chance to enhance our current supplies in an efficient and environmentally friendly manner. Nevertheless, developing new water supplies should be Plan B, something to fall back on once we’ve exhausted all the other options available to us. This means better leak detection, infrastructure repair and improvement, public outreach, and all other manner of water efficiency and conservation techniques we regularly discuss in Water Efficiency.
Ultimately, a cheaper—and more responsible option—would be for water-strapped communities to focus on demand reduction (via smart irrigation, low-flow fixtures, and public outreach) and increased conveyance efficiency (leak detection, infrastructure repair). Additionally, new sources in the form of water recycling (for irrigation and other non-potable uses) and rainwater harvesting should be explored before building any large, water treatment facility.
What do you think? Can our water crisis be solved by focusing on new sources (like desalination and reuse) or can small fixes (stopping that leak, convincing users to turn off that faucet) have a larger impact?