Date: Tue, 18 Jul 1995 09:02:40 CST6CDT
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: "Dan Houg" <fairwind@northernnet.com>
Subject: water tank sanitizers
this is work related so i'll indulge myself with another post.
there are 3 common sanitizers in the food industry that would also be
applicable to sanitizing our water holding tanks. the first and
fore-most point is that none of these will work unless the tank is
clean, meaning free of sludge, sediment, guck, pump labels (oh yes,
mine came off in a big way) and other assorted biofilms. clean means
removing the cover and scrubbing the tank with a mild, non-abrasive
cleanser and pad combo. i would reccomend the 3M dish washing pads
that have a pink sponge on one side and a *white* scrubby pad on the
other. you do not want to scratch the plastic in cleaning as this
would give a nice home for bacteria to hide in. get the tank clean
and white, period.
THEN you think about sanitizing it.
1. chlorine compounds. best on to use is bleach as its cheap and
available. yes it is corrosive and will do nasty things to pump
parts and water level guages if used indiscriminantly. BUT it is
safe, cheap and works. you want to achieve an effective
concentration of 50 parts per million chlorine for sanitizing. this
works out to about 1 tablespoon bleach per gallon. let it sit in the
tank half an hour and dump it out. rinse it out a little with fresh
water and you're on your way.
2. Quaternary Ammonium products. there are a variety of products
available in food service catalogs that utilize this active
ingrediant for sanitizing. it also works and has the advantage of
being non-corrosive BUT it is hard to get, expensive and has a really
long chemical name that would scare most cockroaches. mix to an
effective concentration of 200 ppm.
3. iodine compounds. again, non-corrosive and to use you want to
reach an effective concentration of 12.5 ppm. this means you mix it
up with water to the color of Dos Equis beer. it will turn
polyethylene brown. if you spill it on your Westy cabinets it will
leave a rude brown stain. it will stain your fingers a rude brown.
and it ain't so cheap.
here's my personal recommendation, soley my opinion. clean your tank
well, you should need to do this only once. then sanitize with bleach
at a tablespoon per gallon. i don't worry about corrosion at these
concentrations and contact time. after your trip, take the water tank lid
off and put a piece of cloth over the hole secured with a rubber
band. this will let the tank dry out and nasties won't grow. next
time you use it you may not even need to sanitize.
chemical test papers that show the effective concentration of these
sanitizers are available from restaurant supply houses, but you
really don't need them.
-dan
Daniel Houg
Minnesota Department of Health
Internet Address: fairwind@northernnet.com
Fax #: 218/755-3823