Colored water bottle paranoia?

A

American Puukko

Joined
Jan 24, 2008
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Here's the deal: Because in an emergency UV and heat from direct sunlight can kill waterborne cooties inside a clear plastic bottle I prefer to carry one just about everywhere I go.

I usually buy Nalgene bottles because they are made in America. I have taken pains to buy non-colored bottles so as to allow the full spectrum of light into the bottle in case it is pressed into passive water purification.

Then today I temporarily lost my transparent Multi-Drink in the snow near a trail that had a lot of prior depressions and holes in its snow cover. The bottle was found, but I have little doubt I'd have found a colored one faster and without as much of a workout backtracking for it.

The question is, since UV and heat are the factors in passive sunlight purification in the bottle, does it matter to this task which part of the visible light spectrum the color reflects?
 
You should use clear bottles for passive germ killing, although how it's done involves at least 6 hours of direct sunlight on the bottle AND with a reflector underneath.

I think you have better solutions for hiking, backpacking and even survival situations. A portable filter or various chemical methods are faster and more effective.

Personally, I prefer metal because I can boil the bottle in 15 minutes. You may not have a source of direct sunlight when you are in the outdoors, let alone 6 hours and use of a reflector.
 
I recall reading that the international groups who promote clear plastic bottles for solar water purification in Africa recommend doubling the sun exposure time if the bottle is not clear, if the water is murky or if the sun is somewhat obscured. If that advice applies to your question, you might have a long wait with a colored bottle.

DancesWithKnives
 
ultraviolet light is not visible to the human eye so by that definition it doesn't matter if the bottle reflects all the visible light spectrum or not.

as for your clear bottle, an orange duct tape or paracord around it would solve your misplaced problem.
 
When using a plastic Nalgene, after wrapping several feet of duct tape on it, I place underneath four micro pur tabs. That will treat a gallon. Suggest you do this same with colored duct tape. That should solve your dilemma. You keep your clear bottle, it is now visible with tape, and you can treat water before going the more questionable and longer UV route.
 
I think you should go ahead and attach a long high vis paracord lanyard in orange.
You have extra cordage, and an easy way to spot the bottle.
Now, you don't compromise the clearness, either.
 
I agree that although this method of pasturization of water works in theory, it requires a great deal of time and nearly perfect solar conditions. I'd just carry whatever bottle you are most comfortable with and have alternate means of purification. I'm not sure where you are but this method was originally written up and publicized for Africa where getting long periods of uninterrupted sunlight is not an issue for more than half of the year.

In short, it's a great little tidbit to keep filed in the back of your mind for a last ditch method of purification but for practical reasons it's not one you want to rely on as a primary means and therefore shouldn't limit one of your most used pieces of kit to only clear plastic bottles.
 
I just want to be clear here, :p, I don't rely upon passive UV for primary water purification, I have a MiniWorks for that, which fit the 63mm Nalgene bottles and others I own.

The question about UV and colorless plastic is about a last resort, or one that can be used in a variety of circumstances as a possible "pretreatment" that doesn't require fuel.

I realize that UV is out of the visible spectrum, but do not colors closer to the UV end of the spectrum, say deep blues and purples, hold the possibility of blocking or interfering with the transmission of some UV to the water?
 
American Puukko said:
I just want to be clear here, :p, I don't rely upon passive UV for primary water purification, I have a MiniWorks for that, which fit the 63mm Nalgene bottles and others I own.

The question about UV and colorless plastic is about a last resort, or one that can be used in a variety of circumstances as a possible "pretreatment" that doesn't require fuel.

I realize that UV is out of the visible spectrum, but do not colors closer to the UV end of the spectrum, say deep blues and purples, hold the possibility of blocking or interfering with the transmission of some UV to the water?
Click to expand...

If you are that afraid about 'last resort' water purification solutions, why not go with one of the stainless steel ones then you can boil right in the water bottle. You don't have to buy a fancy Guyot/nalgene one for $20 either. Plenty of single walled (albeit not quite as good quality especially in the lids) options out there for $10.

I'd rely on boil water method rather than UV disinfection any day of the week.
 
American Puukko said:
I just want to be clear here, :p, I don't rely upon passive UV for primary water purification, I have a MiniWorks for that, which fit the 63mm Nalgene bottles and others I own.

The question about UV and colorless plastic is about a last resort, or one that can be used in a variety of circumstances as a possible "pretreatment" that doesn't require fuel.

I realize that UV is out of the visible spectrum, but do not colors closer to the UV end of the spectrum, say deep blues and purples, hold the possibility of blocking or interfering with the transmission of some UV to the water?
Click to expand...

For that purpose I'd stash a few big collapsible bags. Platypus or such like. You can carry a few larger sized bags, which lets you sun-purify water in bulk.

That is, if solar purification works in plastic water bags. I think it would, but I don't know.
 
CWL said:
You should use clear bottles for passive germ killing, although how it's done involves at least 6 hours of direct sunlight on the bottle AND with a reflector underneath.

I think you have better solutions for hiking, backpacking and even survival situations. A portable filter or various chemical methods are faster and more effective.

Personally, I prefer metal because I can boil the bottle in 15 minutes. You may not have a source of direct sunlight when you are in the outdoors, let alone 6 hours and use of a reflector.
Click to expand...

These guys do not mention a reflector, although it would probably help: http://www.sodis.ch/methode/index_EN

A sheet of aluminum foil would not take up much space/weight and has other uses.
 
American Puukko said:
Here's the deal: Because in an emergency UV and heat from direct sunlight can kill waterborne cooties inside a clear plastic bottle I prefer to carry one just about everywhere I go.

I usually buy Nalgene bottles because they are made in America. I have taken pains to buy non-colored bottles so as to allow the full spectrum of light into the bottle in case it is pressed into passive water purification.

Then today I temporarily lost my transparent Multi-Drink in the snow near a trail that had a lot of prior depressions and holes in its snow cover. The bottle was found, but I have little doubt I'd have found a colored one faster and without as much of a workout backtracking for it.

The question is, since UV and heat are the factors in passive sunlight purification in the bottle, does it matter to this task which part of the visible light spectrum the color reflects?
Click to expand...

How long must you expose viruses in a bottle to UV light to kill them?
 
Thomas Linton said:
These guys do not mention a reflector, although it would probably help: http://www.sodis.ch/methode/index_EN

A sheet of aluminum foil would not take up much space/weight and has other uses.
Click to expand...

You didn't click the link that shows optimal application, you just read the cover article.

step3_e.jpg


http://www.sodis.ch/methode/anwendung/index_EN
 
The SODIS method is very easy to apply: A transparent PET bottle is cleaned with soap. Then, the bottle is filled with water and placed in full sunlight for at least 6 hours. The water has then been disinfected and can be drunk.

Important points to consider when applying the SODIS method

Step 1
Material, colour and shape of the bottle

We recommend using PET bottles in the application of the SODIS method because they are light and do not break. They are also easy to obtain in many regions. However, glass bottles or special bags can also be used. PET bottles are usually labelled as such, but they are not called by the same name in all countries.
Factsheet Glass vs. PET (EN, FR, ES)
Factsheet Bottle vs. Bag (EN, FR, ES)
Factsheet Use of Bags (EN, FR, ES)

The bottles must be transparent and colourless. PET bottles often have a bluish tinge. This is not a problem. Heavily scratched bottles must be replaced.

Factsheet Ageing of bottles (EN, FR, ES)

The bottles must not hold more than 3 litres.
Factsheet Depth of water (EN, FR, ES)
Step 2
Turbidity

If the water is very turbid, the effectiveness of the method is reduced. It is very easy to determine whether the water is sufficiently clear:

The filled PET bottle must be placed on top of a newspaper headline. Now one must look at the bottom of the bottle from the neck at the top and through the water. If the letters of the headline are readable, the water can be used.

If the letters are not readable, the water must be filtered. This test corresponds to a turbidity of 30 NTU.
Factsheet Turbidity (EN, FR, ES)

Step 3


Cloudiness

Cloudiness affects the strength of solar radiation and thus also the effectiveness of the method.

Rule of thumb:

* If less than half of the sky is clouded over, 6 hours will be enough to completely disinfect the water.

* If more than half of the sky is covered with clouds, the bottle must be placed in the sun for 2 consecutive days.

Factsheet Cloudiness (EN, FR, ES)

Rain

The method does not work satisfactorily during lengthy periods of rain. On these days, we recommend collecting rainwater.
Step 4
Preventing recontamination

The treated water should be kept in the bottle and drunk directly from the bottle, or poured into a cup or glass immediately before it is drunk. In this way, it is possible to prevent the treated water from becoming contaminated again.

Training material

. . .

Where should I place the bottles?

Lay the bottles on a clean surface in the sun, where no shadows will fall for the whole treatment time.

If possible, lay the bottles on a reflective surface, like a sheet of corrugated iron, and protect it from cooling by the wind. The reflection and higher temperature will speed up the disinfection process. However, this is not essential for the application. The bottles can be set down on any surface (wood, concrete, clay brick, etc.).
Click to expand...

xxxxxxxxxxxxxxxxx
 
Why waste that much time? I could start a small fire, or use my stove and just boil water in my Guyot stainless bottles. Take a small stainless mug, bowl, or pot and just boil the water.
Okay, maybe there's no wood, no fuel for the stove, and the sun is your last resort. Then maybe I'd wish I had plastic. If it comes down to that, I must be in a desert.
 
foxx said:
Why waste that much time? I could start a small fire, or use my stove and just boil water in my Guyot stainless bottles. Take a small stainless mug, bowl, or pot and just boil the water.
Okay, maybe there's no wood, no fuel for the stove, and the sun is your last resort. Then maybe I'd wish I had plastic. If it comes down to that, I must be in a desert.
Click to expand...
It is a waste of time if you have a better method - under all the circumstances.

SODIS is primarily used in non-desert areas. It kills germs passively with no energy supplied by the user. Say you break your ankle and the only water you can crawl to is a beaver pond.

In a Stroud episode he WAS in a desert area and had only water with very high likelihood of rodent contamination. (Think Hantavirus.) He also found old whiskey bottles. Apparently he has never heard of SODIS because he drank the water untreated.

Will you use it? Unlikely. But nice to know to avoid doin' a Stroud.
 
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