contamination of treated water

All of my containers are untreated water, and then I put the filter on when needed to use them.

If I want a clean container, I use an Aquatab, which weighs practically negative weight. Fill container with 750ml of water to get correct ~6 PPM chlorine, and one tablet will nuke it clean in 30 minutes. Then use the water inside to clean the outside of the bottle and other camp stuff that could use a light disinfecting, such as funky underwear and shirts.

Better not swim and then lick your lips…

“Dilution is the solution to pollution” is axiomatic in my industry.

Shaking it out and calling it good, yes, will diminish the treatment efficiency, significantly in some cases.

OTOH, putting an ounce of treated water into the formerly dirty container with 1 ml remaining in it, swirling it all around and dumping out 30 ml of treated water would remove 97% of what was in there.  Do that twice and you’ve gotten 99.9 percent out of what residue remained in exchange for wasting 2 ounces of clean water.

The more time you do it, the better it gets.  Also, the more rinses you perform with a set amount of clean water, the better.  30 ml to get out one ml and repeat with another 30 ml gives 1 – (0.03×0.03) = 99.9 but 15 ml used four times is 1 – (1/16)^4 = 0.99998

“30 ml gives 1 – (0.03×0.03) = 99.9 but 15 ml used four times is 1 – (1/16)^4 = 0.99998″

sheesh, all that goes without saying.

I’ll treat my large soft camp bottle and leave it out in the sun. The sun fries any left over little buggers good. Buggers divided by sunlight plus iodine*** equals safe water.
that’s my mathematical take.

***I think REI still sells iodine tablets.

and yes to ‘dilution is the answer to pollution”. I’m guessing our bodies can fight off a miniscule amount of bad bacteria that our filters may have missed.

“I’m guessing our bodies can fight off a miniscule amount of bad bacteria that our filters may have missed.”

Yeah – maybe 99.9999% or 99.99999% is unnecessary – you probably don’t need that much filtering

“Dilution is the solution to pollution”

That’s funny, I was hiking with Doug and he mentioned that and attributed it to David :)

Sometimes, dilution causes a problem, like it would be easier to extract CO2 from a smokestack with high CO2 concentration, than free air with low CO2 concentration

Not that I advocate CO2 extraction – probably not practical, just an excuse to continue burning fossil fuels

I rarely put untreated water into my pint bottle that I use for drinking

I think I’ll just do what David suggested – rinse it out a couple times

There is also the ‘human factor’… If you adopt the thought that ‘a little does not matter’, then at some point ‘a little’ can become more… and more…

Best to keep good habits… similar to using your turn signal automatically whether there is another car in the intersection or not. I just never  use the dirty water bottle for treated water… always keep them separate. Though your mileage may vary…

Or a belt & suspenders approach: Toss a bit of chlorine or iodine in the dirty water bottle before or after use so what remains in there is being treated, chemically.

This video (and the whole 5 part series) from Gear Skeptic lays out excellent examples of why that extra .00001% COULD make a difference, particularly if you are on the trail for a hundred days on a Thru or are drinking very dirty water.

I think he shows that something like 3% of hikers will theoretically get ill on a 150 day PCT hike drinking treated water 100% of the time because of the buggers that slip through .0001% of the time. Some cysts (Giardia if I remember right?) only need 1 or 2 to make you sick.

I dont fret about it, but i do rinse with fresh water a couple-few times per david’s dilution method if a little dirty water contaminates my bottle. Personally I always have time to prevent waterborne illness in the backcountry. Havent been burned…yet.