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Which chemical for water purification in survival kit? 5

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3Jack3

3Jack3

Civil/Environmental
Aug 3, 2020
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1. [highlight #8AE234]I am looking for a chemical that is suitable for drinking water purification.[/highlight]

This chemical should be included in several personal emergency kits, or survival kits. And it can be used for ultra-light camping with a backpack.

A large emergency kit can be used for personal evacuation during disasters. Such a kit can be called an evacuation backpack, or "bug out bag".

2. I found that [highlight #8AE234]many products in this water purification category contain NaDCC[/highlight] (AKA sodium dichlorisocyanurate). But it is said that [highlight #8AE234]NaDCC will not kill the microorganism cryptosporidium[/highlight], which can cause disease.

3. [highlight #8AE234]Chlorine dioxide could be more effective than NaDCC at killing cryptosporidium. But the lightweight chlorine dioxide products that I found, have a shelf life of just 6 months.[/highlight]

That means relatively high replacement costs in the long run. While water purification tablets with NaDCC claim to have a shelf life of up to five years.

4. What is the best chemical to use for this emergency water purification? [highlight #8AE234]Maybe I should opt for the combination of NADCC tablets, plus a lightweight water filter[/highlight] that removes cryptosporidium from the water?

5. Such a water filter is possible for a large bug-out bag. But such a filter is too big for a mini survival kit, to fit in a jacket pocket.

6. I know that boiling water is the best way to kill microorganisms, including microsporidium. But cooking is not always possible during a disaster situation. For example due to injury, illness or exhaustion. Or due to being trapped in a collapsed building, or on a roof during a flood, etc.

7. I've searched for information on these topics on websites on disaster relief, development aid, mountaineering, backpack camping, survival and prepping. But I have found a lot of very unclear and contradictory information on these topics.

8. I hope the readers on Eng-Tips are willing to give me some advice. I would be very happy with all your thoughts and web links on this topic. I am also open to suggestions from non-experts. Thank you very much in advance!
 
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Many years ago my neighbour experimented with a similar kit whereby he made an emergency kit in a candy tin(about the size of a cigarette packet). For water purification he had some small fuel "tablets" and used the tin as a saucepan in which to boil the water. He could probably only boil about 100ml at a time but in an emergency situation better than nothing.


Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
 
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[highlight #FCE94F]ashtree said: "he made an emergency kit in a candy tin (about the size of a cigarette packet). For water purification he had some small fuel "tablets" and used the tin as a saucepan in which to boil the water."[/highlight]

Thanks for your reply. There are thousands of videos on the web about these mini survival kits, commonly known as "Altoids Survival Kits". Would it be safe to boil water in such a metal tin? Or would the water then get contaminated by the metal?

Personally I have made a small aluminum container for a mini survival kit, also to save weight, in comparison to a small tin.

Which fuel tablets can purify water?
 
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3jack3, think you will find the fuel tablets were used to boil the water.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
 
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[highlight #FCE94F]IRstuff said: "Iodine, according to: "[/highlight]

Thanks for the weblink. This website says: "Cryptosporidium cannot be killed or inactivated with most chemical treatments, including iodine and chlorine tablets. (Chlorine-dioxide has been approved but it takes up to 4 hours.)"

CDC says: "Chlorine dioxide tablets can be effective against Cryptosporidium if the manufacturer’s instructions are followed correctly. Iodine and iodine-containing tablets (tetraglycine hydroperiodide) or chlorine tablets are not effective against Cryptosporidium."

 
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[highlight #FCE94F]LittleInch said: "Well this stuff claims 5 years. Says 6 months for holding the water.
"[/highlight]

Thanks for responding. Katadyn Micropur Forte MF 1T water purification tablets contain:
- Troclosene sodium (AKA NaDCC) 99.8 mg/g
- Silver 1.8 mg/g

This product does not contain chlorine dioxide, so it will not kill Cryptosporidium IMO.

 
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It appears silver nano particles work against cyryptosporidium, to some degree:
More to the point, silver ions also appear to work:
Given the short shelf live of Chlorine Dioxide anything silver based may be your best bet for chemical disinfection. Next question would be nano particles vs. ions (I think the latter, but that just a gut feeling).

Potassium permagnate has been used for water disinfection, it also appears to work against cryptosporidium. DOC and oxidation byproducts may be a problem.

Thinking outside the chemical box (bottle?), once ould check if disinfection via sunlight (put water in PET bottle, or other material translucent to UV (not glass), place in sunlight, wait) is viable for cryptosporidium - from skimming the abstract, it appears so: For your survival kit you could find a few small translucent water bags to roll up until use.
 
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[highlight #FCE94F]MartinLe said: "It appears silver nano particles work against cryptosporidium, to some degree:
More to the point, silver ions also appear to work:
Given the short shelf live of Chlorine Dioxide anything silver based may be your best bet for chemical disinfection. Next question would be nano particles vs. ions (I think the latter, but that's just a gut feeling)."[/highlight]

Thanks for your elaborate and creative response. I admit that I did not study the whole challenging WHO research report, but this report does not encourage application of silver in drinking water treatment. On pages 50 - 51 I found the following conclusions:

Quote: "It is difficult to draw any strong conclusions about the efficacy of silver (ionic silver and silver nanoparticles) in drinking-water treatment because of the wide range of approaches used in the various studies reviewed. (...)

In drinking-water treatment applications, silver (ionic silver, experimental silver nanoparticle applications and silver-coated ceramic filters [ionic silver and silver nanoparticles]) has generally only shown to be effective against bacteria (...) most notably E. coli, with relatively long contact times.

Based on the current available evidence, which is particularly limited for viruses and protozoa, silver does not appear to meet the WHO minimum performance recommendations for POU treatment products, which require effectiveness for two of the three pathogen classes. This is, partly, because of the paucity of data documenting performance efficacy against these classes of microbes in water.

In the one study on protozoan parasite reduction by silver, there was only limited effectiveness on Cryptosporidium infectivity and a log10 reduction was not documented.

For silver ions and nanoparticles, only one study on bacteriophage reduction in water has been reported, with effective log10 reduction (i.e. 3–4 log10 reductions) by ions and “biogenic” silver (zerovalent silver nanoparticles on a bacterial carrier matrix) but not by chemically-produced nanoparticles. (...)

Furthermore, it should be noted that relatively long contact times were required for effectiveness, which would reflect conditions where water would need to be stored. (...)

The body of evidence on safety seems to suggest that silver (in ionic form or as silver nanoparticles) is toxic to mammalian cells, (...)

there is accumulating evidence from mammalian in vivo data, especially with silver nanoparticles, that suggest that exposure to silver may result in toxic effects in exposed subjects, given sufficient dosage and lengths of exposure. (...)

the current evidence is sufficient to indicate that:

- Silver has not demonstrated significant capability to be considered a candidate for primary disinfection of drinking water. There are insufficient data to document that it acts against a broad spectrum of pathogenic organisms.

Performance efficacy has been adequately documented only for some bacteria and not for viruses and protozoan parasites. The impact of water chemistry is often neglected in efficacy studies, and further, long contact times are generally required. (...)

- In some studies, at least, silver may be toxic to mammalian cells in vitro, and there is an indication that some toxic effects can also be seen from in vivo animal studies. (...)

On the basis of the significant data and performance gaps in disinfection efficacy as a primary disinfectant of water, the limited data on the range of microorganisms against which it is effective and under what conditions, and the availability of widely used, well-characterized disinfectants, silver is not recommended for use as a primary disinfectant in drinking-water supplies at this time."
 
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[highlight #FCE94F]bimr said: "Rather than pills, you would be better off with a lifestraw: [/highlight]

Thanks bimr, a lightweight water filter can filter cryptosporidium and bacteria, but not all viruses i think. Therefore, I could combine it with NADCC water purification tablets, which weigh very little, are inexpensive and have a shelf life of several years.

I can find out which lightweight water filter is best suited for an evacuation backpack (bug out bag). Weight limitation will be an important factor in choosing that filter. I will include the Lifestraw filter in my product selection.

I also want to bring some activated carbon in my bug-out bag to filter out chemicals, since I live in an urban environment. And many chemicals cannot be boiled from contaminated water, unlike microorganisms. I want to buy that activated carbon through a webshop.

Putting those items in my bug-out-bag saves me having to bring extra drinking water, which is very heavy. But it takes some readily available clean drinking water, to carry in a bug-out-bag for extreme conditions, such as if I am injured or ill during evacuation. And maybe there is no opportunity to add that drinking water during a disaster to my backpack, or I might panic.
 
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[highlight #FCE94F]Artisi said: "think you will find the fuel tablets were used to boil the water."[/highlight]

Thanks for explaining.
 
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This discussion can be of interest to the military (army, navy, special forces and air force pilots). Water purification tablets can be part of a compact air pilot survival kit.

This discussion may also be useful to civilian pilots, backpackers, bicycle campers, caravan campers, motorists, truckers, hikers, adventurers, law enforcement (police officers in remote areas), shipping, sailors, water sportsmen, off-shore workers, desert travelers, jungle travelers, arctic expeditions, nature expeditions, homeless people, poor families, disaster victims, evacuees, hunters, anglers, developing countries, development aid, governments, NGOs, Red Cross, FEMA, health care providers, health care institutions, bushcraft, hippies, self-sufficiency, off-grid living, homestead lifestyle, EDC, preppers, survivalists, Scouting (boy scouts, girl scouts), voluntary simplicity, manufacturers, and so on.

 
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The nearest open bodies of water from where I live are open sewers (domestic plus industry). I wonder If one can pack the equipment to get potable water from that in a large back pack?

- piece of cloth and ropes or large funnel to make a sand filter
- ditto plus activated carbon for an ac filter (which would be loaded pretty fast from DOC?)
- microfiltration (lifestraw or similar)

... and then you'd still have diverse inorganic nitrogen, phosphate, diverse salts and a lot of stuff I probably forgot about, so
- hand operated reverse osmosis system
- disinfection (NADCC)

What did I forget?
 
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[highlight #FCE94F]MartinLe said: "The nearest open bodies of water from where I live are open sewers (domestic plus industry). I wonder If one can pack the equipment to get potable water from that in a large back pack?"[/highlight]

Thanks for your important question. I could collect ground water, by digging with an improvised "digging stick", at some distance from a river or lake. I can make such a stick with a small folding saw.

I can distill that ground water, by folding a garment a few times, and putting that on an aluminum camping pan with boiling water. Between that garment and the pan I can put an improvised mat, that I braid on the spot, with green twigs from a non-toxic species.

The steam will condense against the garment. After some time I can wring out the soaked garment in a plastic box.

Then, if necessary, I can filter the distilled water with my activated charcoal, to remove any remaining chemicals. See survival videos on the internet, about an improvised carbon filter with a plastic bottle.

Or I can first filter the water with sand, grass and fabric, and then with the activated charcoal, that I brought in my backpack.

Then I can treat it with an NaDCC tablet. In addition, I could expose the water to sunlight for additional treatment against micro-organisms.

I could also distill urine or sea water with an improvised distillation method, like solar distillation.

These techniques may not be easy to apply in an emergency, but could be life-saving in a disaster IMO.
 
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