Lightweight Water Treatment Backup

Posted by: billstephenson

Lightweight Water Treatment Backup - 12/16/13 10:17 PM

It's been my feeling that if you use chlorine dioxide you should filter the water afterwards and I once recommended that using an activated charcoal filter would remove the chlorine. There was some discussion here on that, and the general consensus, as I recall, was that it would not remove it.

That's sort stuck with me because I know it removes the taste of chlorine and after reading about what happened to OM with her Sawyer Squeeze locking up I started thinking about this some more.

So I started looking today for what an activated charcoal filter actually does removes that tastes like chlorine. From what I found, it actually does remove chlorine pretty good, there is a time factor involved though. The longer the water is in contact with the activated charcoal the better it works. Here's what I've been reading:

www.ianrpubs.unl.edu 1

www.ianrpubs.unl.edu 2

www1.agric.gov.ab.ca


So, based on that I think pretreating with chlorine dioxide and then using an activated charcoal filter is probably a pretty safe, inexpensive, and lightweight method to treat water for our purposes. But more to the point is that even if you carry a filter this makes a good back-up system. Just a few tablets of chlorine dioxide and one of these Dollar Store lightweight collapsable bottles with an inexpensive Britta activated charcoal filter inside them is cheap and light, and it could save a trip:



This also works great to pre-filter and boil water. Boiling water is really all you need, but this way sure beats nasty tasting water that crunches between your teeth wink
Posted by: Rick_D

Re: Lightweight Water Treatment Backup - 12/16/13 11:43 PM

Oh yes, carbon definitely removes free chlorine--I have a big undersink filter in the kitchen primarily for that--and an A/B comparison with unfiltered water can be night/day, depending on the season and how much they're chlorinating. Takes out all sorts of organics, too.

Since I can usually taste/smell ClO2 in treated water, polishing it with carbon makes perfect sense (scents?).

Cheers,
Posted by: OregonMouse

Re: Lightweight Water Treatment Backup - 12/17/13 02:46 AM

Be sure to leave the chlorine in the water long enough to do its job! That could be up to 4 hours if the water is cold and really turbid!
Posted by: lori

Re: Lightweight Water Treatment Backup - 12/17/13 10:33 AM

Chlorine dioxide isn't the same as the chlorine used in tap water...
Posted by: BZH

Re: Lightweight Water Treatment Backup - 12/17/13 12:36 PM

I have been thinking about this some recently. No one seems willing to tell us how effective these Brita type filters are at removing things but that doesn't mean they are not effective. I think the facts are that they do not filter out the bugs that make us sick so companies are very leery of making promises about what they can do lest they be sued when someone uses it as their sole water treatment.

The fact is activated carbon is very effective at bonding to and neutralizing a lot of pollutants in water that might not make you sick right away but could over a long period of drinking them. If you ingest poison one of the more common treatments is a little capsule of activated carbon. How can that little capsule be effective at saving my life when I directly ingest poison but an entire tube of it be worthless for treating mildly polluted water?

With CLO2 I think the proof is in the taste. If much of the CLO2 taste is removed with carbon treatment, then it is probably a pretty effective treatment.

A more serious issue came up over at BPL: that of blue-green algae aka cyanobacteria. Standard water treatments will kill cyanobacteria but none of them (filter, clo2, steripen, boiling) will remove the toxins they produce. If you get cyanobacterial poisoning, the treatment is activated carbon, but I can find no guidance on using the activated carbon to treat the water before you drink it.

So... I suspect those little brita filters could be very useful but I have no direct information at just how useful they are.
Posted by: Rick_D

Re: Lightweight Water Treatment Backup - 12/17/13 12:46 PM

Originally Posted By lori
Chlorine dioxide isn't the same as the chlorine used in tap water...

True, and my hunch is the carbon will adsorb either. This may call for an experiment or three.

Cheers,
Posted by: Rick_D

Re: Lightweight Water Treatment Backup - 12/17/13 12:49 PM

Originally Posted By OregonMouse
Be sure to leave the chlorine in the water long enough to do its job! That could be up to 4 hours if the water is cold and really turbid!


Yes, it should be considered a "polishing" step to improve taste and odor, not part of the actual treatment regimen. And hopefully, turbidity has been addressed by prefiltering or flocculation.

Cheers,