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?