On Tue, 10 Dec 2002, Sean Solowiej wrote:

> I have heard that some of the mechanized car washes are designed to RE-USE
> their water.  If this is the case, and salt is what you want washed off, I
> would avoid them.  Does anyone else have info in this?  (David Brodbeck, do
> you have inside info?)

The washes the company I work for designs usually use recycled water for
the high-pressure wash stage, but the final rinse uses softened tap water.

To do an effective job cleaning vehicles in a touchless wash you need a
*large* volume of water.  That gets expensive in a hurry with fresh water.
I know a certain amount of chemical treatment is done on the recycled
water (to help sediments settle out, to get rid of oil, and to keep the pH
balanced, for example) but I don't know all the details; that isn't my
department.

The car wash I run my own cars through uses this type of system and I've
never noticed a salt film on the car after washing it.  I've heard
complaints about that happening at other car washes, though.

             _ _
  __ _ _   _| | |  | David M. Brodbeck (N8SRE)              Ypsilanti, MI
 / _` | | | | | |  +-----------------------------------------------------
| (_| | |_| | | | @ cyberspace.org
 \__, |\__,_|_|_| "To the optimist, the glass is half full.  To the
 |___/             pessimist, the glass is half empty.  To the engineer,
                   the glass is twice as big as it needs to be."