posted on Oct, 1 2009 @ 12:34 AM
There's one thing that surprises me though, why don't some coastal states further pursue active desalination? There's still more than enough ocean
to go around in those areas. Is there really a good excuse not to?
Now a lot of people will say "Hey! That's energy intensive and expensive!" But there is a logical counter for this. Institute it as a required
coproduction process for any new steam-cycle power plant within so-many-miles of ocean coastline. Any coal fired, oil burning, or nuclear plant that
runs boilers or steam generators to turn the turbines can effectively work towards desalination while doing its normal job of making electricity. You
may find it surprising just how many gallons per day can be made by pumping waste heat used in the condensing process through a vacuum distiller
instead of some otherwise useless cooling tower. (Under ideal conditions, with cool seawater and the steam plant at peak power, we're talking 10's
of thousands of gallons per day if not much much more.) And it's not like it's a terribly new technology, I believe this type of technology for
multi-stage flash distillation
has been in use for freshwater production on
steam powered sea-going ships since the late 1800s. So it's not a problem of proof, but of industrial sized scaling. (Yet any engineer capable of
solving problems in moving a lot of water that's worth his salt should be able to figure it out.)
Of course compared to a city scale, it may still seem like a limited amount. But consider the uptime a typical powerplant has. Now multiply days of
powerplant operation with the average gallons produced per day with the process. Now pump that output back into a reservoir or aquifer. You might
actually be putting back a nice chunk of volume during those periods of low water demand, and while not worrying if nature will do the job. (And if
nature actually does its job, switch the lineup to standby cooling. And use it as an opportunity to do whatever maintenance is needed on your
"rainmaker". It doesn't take a genius.)
There are some places that do this, but why not much more?
It's very likely to still be a maintenance intensive process. There will be
mineralization that has to be controlled on the seawater feed, and then on the brine discharge side there's going to be some rather high salinity
that will need to be diffused so as to not screw up the environment. So these challenges make it a bit more difficult, but not impossible. Yet if
there is technological capability and good engineering, this is at least one solution that is well within reach if needed.
I guess money is the only other logical excuse for not doing it, but I feel it's a rather lame one.