Date:         Wed, 1 Jan 2003 17:22:14 -0700
Reply-To:     Ben McCafferty <ben@VOLKSCAFE.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ben McCafferty <ben@VOLKSCAFE.COM>
Subject:      Re: Water Treatment / Purification
Comments: To: Jim Arnott <jrasite@EONI.COM>
In-Reply-To:  <3E1338BF.7070904@eoni.com>
Content-type: text/plain; charset="US-ASCII"

Hey Larry,
Applying backpacking experience to this.....

There are basically two approaches to the problem, filtration or chemicals
of one sort or another.  Most ceramic filters these days can filter out all
bacteria (giardia, cryptosporidia, etc.) but will miss viruses, because
viruses are so much smaller than bacteria.  Chemical treatments (tablets,
iodine crystals, etc.) will get everything, including viruses.  The old way
to use a filter and still kill viruses was to run water through an iodine
pre-filter, then the main filter which removed the iodine taste and
bacteria.  This meant you could only filter a certain amount per hour, to
let the iodine pre-filter recover.  Another trick from the trail is to let
the iodine or chlorine tablets do their thing, then set the open bottle of
water in direct sunlight for about 20 minutes, and the iodine/chlorine taste
would disappear as the treatment oxidized out of the water.

Whatever you decide on, keep in mind that you should always have a method to
clean your filter, and a backup plan.  On the trail, I carry a Sweetwater
Guardian filter with a cleaning kit and an extra filter for long trips.  I
also have a small bottle of iodine tablets in case the filter clogs.  If you
are filtering really murky water, a sock or a sediment filter on the intake
hose will increase filter life dramatically.

I may have missed something in recent technology and am open to corrections,
but I think Jim actually has it backwards below--filtration misses some
things, and chemicals get everything.  I do endorse the tequila method,
though.... :)

tx,
bmc  :)
Ben McCafferty
ben@volkscafe.com

Volks Cafe
1823 Soquel Avenue
Santa Cruz, CA  95062
831-426-1244
http://www.volkscafe.com


>
> AFAIK the only way to ensure safe drinking water from an unknown source
> is filtration.  Chemicals apparently miss some of the more persistant
> bacteria.
>
> Tequila works too...
>
> Jim
>
> Larry Chase wrote:
>
>>
>> There was talk of filters (charcoal and such) and other treatment
>> approaches.
>>