Sterilizing water in developing countries

[mvweebles]

Originally Posted by sv_pelagia

Actually, chlorination alone is NOT very effective against Giardia (linked article also does not indicate chlorine alone is effective). FYI, neither is iodine.

Bringing to a boil (even for 1 second) is always effective against Guardia (even at high altitude... not an issue on boats).

15 trips trekking in Nepal has taught me a lot (with much concomitant reading) about giardia and treatment of giardisis. We always carry Tinidazole for treatment... and have had to use it a few times.

In my opinion, every traveler (vs vacationer) should include Imodium (flagyll) in their bathroom kit. It just happens.

Issue with Mexican water (and many third world countries) is wells are indiscriminately drilled and are shallow. Giardiasis is just one of the ailments and is the most common source of diarrhea. Especially in urban centers like Ensenada, the water can have a host of disagreeable substances such as heavy metals that do not dissipate over time but build up in the body.

Giardia is a large cyst that is fairly easy to filter - the article states 7-10 microns. But many of the heavy metals form soluble salts. I personally do not use tap water for anything that will be eaten. Fine for showers and washing. Of course, the only way to know for sure is a lab test.

Bottom line. The bottled water "garafones" come from reputable water treatment sources. This is what local Mexican families do too.

Peter

[Jammer]

Originally Posted by mvweebles

In my opinion, every traveler (vs vacationer) should include Imodium (flagyll) in their bathroom kit. It just happens.

Imodium is not Flagyl.


Imoduim is a trade name for loperamide, an opioid that does not cross the blood-brain barrier that is used as a anti-diarrheal medication. It works by slowing the perstaltic action of the intestines, and replaces earlier opiod medications such as paragoric, that posed problems with dependency and other CNS side effects. Imodium treats the symptoms of diarrhea, regardless of the underlying etiology. The main risk is constipation, which clears when the medication is discontinued.



In contrast, Flagyl is a trade name for metronidazole, an antibiotic and antiprotozoal medication. It can be used in treatment of diarrhea where a bacterial or protozoal infection is the cause, though it is no longer usually considered a first-line treatment. Like other powerful antibiotics, there is a risk of life-changing allergic reactions in rare cases.


This is, of course, not medical advice for anyone's particular medical situation, and Jammer is not a real doctor. Carry on.

[Tetepare]

Originally Posted by Jammer

Imodium is not Flagyl.


Imoduim is a trade name for loperamide, an opioid that does not cross the blood-brain barrier that is used as a anti-diarrheal medication. It works by slowing the perstaltic action of the intestines, and replaces earlier opiod medications such as paragoric, that posed problems with dependency and other CNS side effects. Imodium treats the symptoms of diarrhea, regardless of the underlying etiology. The main risk is constipation, which clears when the medication is discontinued.



In contrast, Flagyl is a trade name for metronidazole, an antibiotic and antiprotozoal medication. It can be used in treatment of diarrhea where a bacterial or protozoal infection is the cause, though it is no longer usually considered a first-line treatment. Like other powerful antibiotics, there is a risk of life-changing allergic reactions in rare cases.


This is, of course, not medical advice for anyone's particular medical situation, and Jammer is not a real doctor. Carry on.

Jammer may not be a doctor but Jammer is right. Thanks for correcting that really stupid “information”. The wonder of the internet is rampant misinformation.

That said , flagl and Imodium are both awesome. Just be aware of what they really do.

[ParL]

It all depends on what you are concerned about. Chlorine is quite decvent, but if you are concerned about Cryptosporidium then you will have to increase concentration until it tastes rather bad (the spores are quite protective). On the other hand the parasite spores are comparably large, so any filter that actually works on bacteria will work on them.


Basically there are three kinds of pathogens that you should be concerned about:


Bacteria: everything from your friendly E. coli to Salmonella or even charming exotics like Vibro cholera.


Parasites: these are actually single- or multicelluar animals, and range from the ever popular Giardia and Cryptosporidium to worms and other friendly pets. Any decent filter will handle these, but some form various types of spores, and can then be quite resistant to chemicals.


Viruses: Unless humans have been around you are unlikely to have a problem with these, but then hepatitis A and E is not uncommon, and in some parts of the world (E. Africa, New York, etc) you can even find polio. Very few filters will work on these, chemical purification or boiling is the way to go.


Best: Boiling is the best: bring to a rolling boil and keep it there for 30s to a minute[1].

Pretty good: dedicated water filters that are designed for water purification. I use the MSR Guardian, which even filters out viruses and have a very long filter lifespan (IIRC 10000 litres). It is easy and and quick to pump as well. UV based systems are also good, and here a stainless water tank is an advantage if you have it in the tank. The only concern is if the light does not reach all nooks and crannies of the water container.

Not bad: chemical methods, such as chlorine used in the proper manner (dosage and contact time is important, and not all products are created equal (as opposed to us men, we are pretty much interchangeable, just ask your partner). For Cryptosporidium the chlorine dioxide based products are considered the best, but they often have a short lifespan. Chlorine is quite good against viruses, which is nice if you are concerned about e.g. hepatitis. And one important thing: if you add something that contains vitamin C to the water the chlorine taste goes away, as does the anti-microbial effect. So only add those when you are confident that the chlorine has done its job. Iodine also works well, but is not recommended for long term use, and not at all for some groups (pregnant, children, etc)



Questionable: systems that are not actually designed to purify water for human consumption, filters that only filter out particular matter, <mumble> drops of chlorine bleach/litre etc. The latter is worth an extra caution, for two reasons. The first is that not all bleach is actually chlorine bleach. The second is that if the bottle is shaken and oxygen from the atmosphere is mixed in then the good stuff will be inactivated. And I may not be the worlds greatest expert on sailing boats, but I have the impression that they sometimes move around a bit. And the hypochlorite in bleach is not very effective against Cryptosporidium.


I have a longish text on the web on this subject (What happens when you cross a scientist with a wilderness survival instructor? Answer: me) . It is in Swedish, but sometime in the not too far future I intend to translate it into English. And google translate kind of works these days. There is a pretty good and fairly accessible scientific review titled "Water Disinfection for International and Wilderness Travelers" that I highly recommend.



[1] The pathogens start becoming inactivated at about 60C, so if your stove is slow then just a few seconds of a rolling boil is fine, but keep it there for a short while -- 30-60s -- to be safe. All the stories about 5-10 minutes are inaccurate for drinking water under anything even resembling normal conditions.

[ParL]

Originally Posted by BobFord

Beware of waterborn infection , e.g. Gardia . Usually from raw sewage pollution( crowded anchorages and dodgy land sourced ) I have used the following with zero infection problems , when needed . 20ml bleach + (2) drips Iodine per 400 litres water. Watermaker or land source .

Please note that if your bottle of bleach has been shaken and thus mixed with air then the hypochlorite has to a significant extent been oxidized into non-active compounds. And not all things sold as "bleach" are the same.

[Letterkenny]

Is there any reason that you cannot use or would get the same results of using these filters in a standard 10x2.5 container versus their $500 system?

https://www.clearsourcerv.com/collec...nt-filter-pack

[sv_pelagia]

Originally Posted by ParL

It all depends on what you are concerned about. Chlorine is quite decvent, but if you are concerned about Cryptosporidium then you will have to increase concentration until it tastes rather bad (the spores are quite protective). On the other hand the parasite spores are comparably large, so any filter that actually works on bacteria will work on them.


Basically there are three kinds of pathogens that you should be concerned about:


Bacteria: everything from your friendly E. coli to Salmonella or even charming exotics like Vibro cholera.


Parasites: these are actually single- or multicelluar animals, and range from the ever popular Giardia and Cryptosporidium to worms and other friendly pets. Any decent filter will handle these, but some form various types of spores, and can then be quite resistant to chemicals.


Viruses: Unless humans have been around you are unlikely to have a problem with these, but then hepatitis A and E is not uncommon, and in some parts of the world (E. Africa, New York, etc) you can even find polio. Very few filters will work on these, chemical purification or boiling is the way to go.


Best: Boiling is the best: bring to a rolling boil and keep it there for 30s to a minute[1].

Pretty good: dedicated water filters that are designed for water purification. I use the MSR Guardian, which even filters out viruses and have a very long filter lifespan (IIRC 10000 litres). It is easy and and quick to pump as well. UV based systems are also good, and here a stainless water tank is an advantage if you have it in the tank. The only concern is if the light does not reach all nooks and crannies of the water container.

Not bad: chemical methods, such as chlorine used in the proper manner (dosage and contact time is important, and not all products are created equal (as opposed to us men, we are pretty much interchangeable, just ask your partner). For Cryptosporidium the chlorine dioxide based products are considered the best, but they often have a short lifespan. Chlorine is quite good against viruses, which is nice if you are concerned about e.g. hepatitis. And one important thing: if you add something that contains vitamin C to the water the chlorine taste goes away, as does the anti-microbial effect. So only add those when you are confident that the chlorine has done its job. Iodine also works well, but is not recommended for long term use, and not at all for some groups (pregnant, children, etc)



Questionable: systems that are not actually designed to purify water for human consumption, filters that only filter out particular matter, &lt;mumble&gt; drops of chlorine bleach/litre etc. The latter is worth an extra caution, for two reasons. The first is that not all bleach is actually chlorine bleach. The second is that if the bottle is shaken and oxygen from the atmosphere is mixed in then the good stuff will be inactivated. And I may not be the worlds greatest expert on sailing boats, but I have the impression that they sometimes move around a bit. And the hypochlorite in bleach is not very effective against Cryptosporidium.


I have a longish text on the web on this subject (What happens when you cross a scientist with a wilderness survival instructor? Answer: me) . It is in Swedish, but sometime in the not too far future I intend to translate it into English. And google translate kind of works these days. There is a pretty good and fairly accessible scientific review titled "Water Disinfection for International and Wilderness Travelers" that I highly recommend.



[1] The pathogens start becoming inactivated at about 60C, so if your stove is slow then just a few seconds of a rolling boil is fine, but keep it there for a short while -- 30-60s -- to be safe. All the stories about 5-10 minutes are inaccurate for drinking water under anything even resembling normal conditions.

A good summary....

One problem with many Chlorine Dioxide solutions for cryptosporidium is the requirement of a long contact time (a popular tablet form of CD requires 4+ hours to treat water for crypto).

Filters need to be better for crypto. According to CDC: Absolute pore size of 1 micron or smaller https://www.cdc.gov/parasites/crypto...o/filters.html

[thinwater]

A cheap 1 micron filter that will work for jerry cans, dock filling, and rainwater. Cleanable and can be sanitized between uses in the sun. Super easy, does not slow you down.


https://www.practical-sailor.com/bel...y-water-filter


Hose end filter are not functional IMO, and canister filters quickly get nasty.

[thinwater]

Originally Posted by Letterkenny

Is there any reason that you cannot use or would get the same results of using these filters in a standard 10x2.5 container versus their $500 system?

https://www.clearsourcerv.com/collec...nt-filter-pack

They don't list the NSF ratings of the filters and the manufacture and products names are not in the NSF database. Until they do that, zero points can be awarded. The label does not have an NSF stamp... which is odd for an NSF-rated product. Something is wrong.

[Letterkenny]

Originally Posted by thinwater

They don't list the NSF ratings of the filters and the manufacture and products names are not in the NSF database. Until they do that, zero points can be awarded. The label does not have an NSF stamp... which is odd for an NSF-rated product. Something is wrong.

Think I will likely go with this setup and get some NSF rated filters if these aren’t already and then rely on my second stage carbon/UV water pitcher by my last UV water bottle lids to hopefully eradicate everything. May throw in some bleach as well after the carbon tank pre filter.

[MWhite]

Cruising Mexico, we used chlorine in the tanks when we filled up. More to the point, the availability of water became a headache for me. We carry 300 gallons, so PLENTY of water overall, and we are frugal with it. But it did cause us to have to plan accordingly when the tank was getting low and there are a lot of places in the Sea of Cortez that are far away from everywhere. As the weather heats up, we use more water to keep cool, and since we swim, to rinse off the salt. So that begins to add up. We use a whole house filter, even in the states, but no UV. Added to this was that all the cruising guides will say whether water is 'available' at different marinas, but, turns out, they don't indicate whether the water is potable. That was a learning curve for us as, being from the states, our default is that water at the dock is potable water. That was dead wrong. Most times, it's not potable. Towards the end of our Mexico cruise we bought a water maker from another cruiser. Never looked back.

[BigNut]

Originally Posted by ParL

. There is a pretty good and fairly accessible scientific review titled "Water Disinfection for International and Wilderness Travelers" that I highly recommend.

Thanks so much for the reference, @ParL. Although rather dated, it is excellent.

We only utilize RO water, but the issue of tank hygiene remains, as we are loathe to add any chlorine too frequently, being full-time cruisers and often away from where we can access fresh charcoal filters.

Looking forward to seeing your site translation!

[Don C L]

On commercial river trips I worked on we used this ceramic filter from Katadyn and it worked very well:
https://www.katadyngroup.com/us/en/8...pedition~p6743

Our main concern on those trips was Giardia, but at 0.2 microns, it will catch a lot of other stuff too.

Pricey but worth it IMO.

[nofacey]

An RO watermaker solves most of this issue…..but if you’re stayinging in a Marina, the salt water is potentially oil fouled, which is the kiss of death to RO membranes.
- so no matter what, you need a dock side filter, and chlorine (we used household bleach).

[PirateBarnabus]

What's wrong with rainwater (assuming it rains enough)?