Water purification ideas

Just registered here, and wanted to run a few ideas by people for survival-situation water purification. I've never seen these mentioned in survival guides, so I thought it'd be nice to get some feedback.

1. Quicklime: Quicklime has been around since paleolithic times. It is produced by "burning" limestone. The process takes a very hot fire (825C) -- you usually need a billows or other way to provide extra oxygen, but you don't need charcoal or coal. A primitive kiln (clay or mud bricks) helps, but isn't necessary if you have good airflow. The lime was usually cooked on a flat rock. The result is a caustic, hydrophilic powder that used to be used as a whitewash, in making cornmeal, and a few other things. Quicklime is interesting because it is a flocculant -- a chemical that encourages microscopic particles to coagulate and settle. It's not a very powerful flocculant, but it is used in some water treatment systems in various parts of the world; it not only helps settle bacteria, virii, and "gunk", but even heavy metals like arsenic, lead, etc. There are better natural flocculants (like alum, a major component of many of the latest water purification tablets (for example, PUR); also, iron chloride, iron sulfate, and a number of others), but they're rarer; limestone is all over the place and is easily recognisable.

2. pH adjustment: This, too, is used in some water treatment systems, but usually only on a small scale. Many disease-causing bacteria and virii are very pH-sensitive; exposure to particularly acidic or alkaline environments for lengths of time can kill them or otherwise render them inert. Quicklime is one way to significantly raise pH, but wood ashes can raise it and are much more readily available. I'm not sure of any convenient, safe ways to significantly lower pH unless you're in an area where there is abundant citrus. A downside to this concept is that you'll be drinking whatever you adjust the pH with. Ashes are mostly harmless, and you may be able to filter out much of the ash, but it still wouldn't be tasty.

3. Artificial artesian spring: I once read about this concept being used in rennaisance Italy. It would only be worthwhile if you were going to be in an area for a long time. The idea was that they dug a pit, lined it with material that was relatively water-impermiable, then filled it all up with clay, gravel, and sand except for a "well" in the center. Ideally, the well was lined with a relatively impermiable material as well They'd dump dirty water in the area around the well (which used to be the pit), which would filter through the clay and sand, straining out any contamination, and eventually seep into the base of the well. They could then gather the purified water from it. There might be situations where such a setup might have formed naturally (rock pit filled with dirt), wherein you'd only need to dig the well, although I'm not sure how one would identify such a situation effectively.

Thoughts? Ideas?

I should add that I first started wondering about these, esp. the first, after being in Japan and camping for a night in a place where the only water available to us was volcanic in nature, so it was probably loaded with heavy metals, which we knew that the filter we had on hand wouldn't get rid of. Also, while boiling water is an easy way to kill microbes, if one is lacking a cup or going to be in a single place for a long time, other options might be worth consideration.

KarenRei,

Welcome to the fire! Interesting first post. Is your name Japanese or do you work at my favorite money pit? An introduction is always nice.

Thinking about what you wrote:
1. Quicklime: The flocculant idea is good. Using it to pretreat the water before boiling makes sense.

2. pH adjustment (basic): Similar to using bleach to kill the wee little beasties. Wood ashes produce NaOH (sodium hydroxide) which isn't as good as hyperchlorates in this respect. Contact time would need to be pretty long. NaOH solutions can cause permenant damage to eyes and other soft tissues. In this regards they are worse than acid burns. Controlling the dose of NaOH could be a problem. Which bleach-type chemicals the "sniff test" works (if it smells like a swimming pool after sitting several hours it's safe). I just sniffed our pH 10 calibration solution and couldn't smell anything. Perhaps a "slippery test" might work. Basic solutions can cause your skin to feel slick/slippery. Overall, I'd say stay away from this. If you have fire figure out some way of boiling the fire. The poor result control coupled with risk of damage to your mouth/throat makes this a poor choice in my opinion. Sidenote: "Lutefisk" is a Norwegian dish where raw cod is soaked in a NaOH solution for weeks to preserve it.

2. pH acidic: First thought is water-born beasties survive our stomach acid. That right there seems like and arguement against acid-sterilization. On the Walmart Les Stroud "Urban Disaster" DVD Les preserves raw salmon by soaking it in lemon juice at room temperature overnight. He claims this will remain safe to eat for 3-4 days. He states that it must by lemon juices, others aren't acidic enough and also it only works with fish, not chicken (I can't remember if it works with beef).

3. Artifical well: Cool idea, very similar to a refugee-camp sand filtration unit I posted a few weeks ago. For a long term situation involving a family-unit or larger this could make a lot of sense. I like it.

-Blast

Welcome to the forum! Thanks for stopping by.

These are interesting ideas, but for an emergency (lost hiker, downed small aircraft) situation, they just don't seem that practical to me. I imagine that's why you don't find them in survival guides.

The lack of a metal cup shouldn't stop you from having clean water. We have discussed cup-less methods of boiling water in the forum--hot rocks in the Nalgene, hot rocks in a canvas hat--before and they can work. Or chemical treatment works fine if you have some sort of container. Of course, a hand-pumped filter is another option. Remember, "one is none". It would seem to be a good idea to carry two heat-resistant containers or have two different water purification methods available.

Anyway, like I said, interesting ideas, but they seem more suited for longer-term survival, in my opinion. And even then, their ability to kill pathogens is not going to be as good as the more common methods. Just because ancient peoples used a method doesn't mean that they didn't have to run behind a bush every 20 minutes with the runs.

Welcome aboard. As others have pointed out, these ideas are more for a dug in long term situation, but that's not a bad thing.

For heavy metals, proper filtering is the only way to go. Layers of charcoal and clean sand is what comes to my mind.

As for lacking the cup... *leans close, whispering* Carry a folded up piece of aluminum foil in your wallet. If anyone asks, do as I do- tell them it's the money used at home, but unfortunately there aren't normalized rates of exchange yet. Maybe after the Solarians bow down before their proper superiors and except their place in the Galactic Empire, that will change.

And it makes a useful cup.

Welcome!

Knowledge is always a good thing, but this are just too complicated for an old simple guy like me...

Welcome to the forum.

Very interesting water purification ideas, this is the first time I heard about these methods. But feel it may not be very practical in a survival situation. You may not have the energy / time to build or find the necessary materials. The situation may make it impossible for you to do it.

With the current state of technology, there is better solutions that is more effective and safe, eg. steripen & MSR MIOX purifier.

I had the MSR MIOX purifier and think it work great.

Hi KarenRei, welcome to the site.

Just a few observations about the methods you cited:

1. Quicklime - I like the idea of using a flocculant, but keep in mind it only works on suspended solids, unless it generates a chemical reaction to precipate something in solution, which there is a possibility of, but not comprehensively. Flocculants will clear turbid water, and may capture some biologics, but I would not rely on it to disinfect the water.

2. pH adjustment - Because many of the organisms that cause problems have a level of protection against most common pH levels, you really have to swing it hard to start disinfecting. It can be done, but the subsequent solution is a hazard just to handle, and will have to be neutralized in order to be consumed, which can also create other problems. Water passed through wood ash extracts Lye, which is what changes the pH and is pretty hard on the digestive system. You would want to neutralize the solution, which again introduces chemicals into the water that may not be consumable. Think of it like shocking pool water, you wouldn't want to consume it, much less bath in it. You know, it does bring to mind the idea that carrying a couple pool test strips in my PSK might be of some benefit.

3. Infiltation methods depend on a sterile environment. You might have to go pretty deep to get passed contaminated soil far enough for the straining effect to be reliable. A lot of wells get contaminated from local sewage for being too shallow and/or downstream of the underground effluent gradient. I would still recommend boiling or other approved form of dinsinfection as a minimum.

I encourage you to continue your contemplations. Primitive systems were simple, but not always effective. Look at modern technology, understand what it is you need to accomplish, and see if there's a way to apply more mundane methods to meet the same standards or water quality. MacGyverisms are sometimes more field expedient. There is a certain amount of science behind safe drinking water that goes a bit beyond common sense, so a little more research may be of benefit.

Hope to see many more posts from you. New ideas stimulate thought.

Cheers

Welcome to the forum! Hope to see more of your posts, they seem to have stimulated alot of replies as well as new useable info.

kmat

I was thinking about it more from the "stranded without gear" perspective.

Heh, not a bad idea Is there no end to the usefulness of a sheet of clear plastic and piece of aluminum foil?

Re, flocculants: I ran into a study on various flocculants looking at how well they precipitated heavy metals (specifically, the study was about arsenic -- I could probably dig it back up). The candidates ranged from 40-90% of arsenic removed -- not perfect, but certainly better than nothing. Boiling doesn't remove any heavy metals, and filters (even activated carbon) usually don't remove much. Flocculants do remove a significant percentage of microbes, although you obviously don't get the 99.99...% that you get with a good filter. I seem to recall the numbers that I've seen being something like 80-90%.

Re, ph: I ran into another study on clostridium (heh, it was all of these studies that got me curious) -- the genus that includes the sources of botulism, gangrene, colitis, tetanus, and others -- which mentioned that they're very sensitive to low pH (I think it was a pH of 5.0 that was lethal to them), and lowering the pH is a good way to waterborne clostridium species. I've ran into pH treatments for other species as well, some high, some low -- don't remember which species were which, though. Certainly, of course, some diseases are hardier than others. I'd imagine that most cystic species, such as giardia, would probably be resistant to pH changes.

Thanks for all the feedback Don't plan on actually using any of these techniques any time soon, but just trying to flesh them out in case I ever do.

Here are some others, mentioned before in other threads.

Sodis- solar water treatment using the sun and a large pop bottle.
effective on bacteria and virus.

Sari cloth filter combined with settling,
good for cholera.

biotic sand filters,
after a couple of weeks, biotic organisms grow that will
eat even metals as well as bacteria and virus. No need for charcoal. Locally they took care of a large diesel spill
by piling up the dirt and inoculating the soil with oil
eating bacteria.

Neat ones -- I'll definitely have to remember those Plastic trash can sometimes be found in the most remote places; other fine-weave cloth (for example, nylon or spandex) could probably fill in for Sari; and the sand filter sounds like it would complement the artesian concept nicely (it'd just require a larger, slower moving seep to give bacteria time to clean it; you'd probably have to mulch the top with dead grass or gravel to lower evaporation).

Yes, but only if you confuse them. The plastic cup might get tricky, and you'd have to be very skinny to stay dry under aluminum foil.

Here is a link to a bunch of water treatment files for rural
and developing countries.

http://www.lifewater.org/resources/water_treatment.html#WT

Interesting that in this file:
http://www.lifewater.org/resources/rws3/rws3m.pdf

They claim that simply "storing" water in containers for 2 days or more will reduce the level of bacteria (up to 90% for two weeks). They do say that to be sure that it is safe the water would need further treatment.

While no help in a short-term situation and only somewhat better than nothing, this info might shed some light on our concerns about long-term storage of water. Perhaps time IS on our side.

Has anyone heard of this before?

No, but it might help explain why more sailors didn't die from tainted water (as opposed to scurvey, etc.) in the age of sail. Unpurified water dumped in an oak cask sometimes months before they drank it - ugh. I always assumed that it was natural resistance, but who knows?

Very interesting topic. More relevant to long-term situations, but definitely worth discussing.

I've heard that certain formulations of concrete are being used to create a slightly porous matrix that will effectively filter harmful organisms out of water. This was in the context of third-world development. It seems more likely that this would work better for larger organisms -- water-borne parasites, amoebas, protozoans, etc. that cause a lot of carnage in the developing world.

I don't have a link (yet) but will look around.

Interesting. Sort of like the Katadyn ceramic filters? I have one of those and just love it. Doesn't help with heavy metals or organic contaminants like pesticides, so you don't want to use it on agricultural or industrial runoff, but it's great for biologicals. When it clogs with bacteria, you just pull out the abrasive pad, rub off the outermost coating of ceramic, and it's good to go again; you can repeat hundreds of times on a single filter.

My filter is one of those siphon ones, which is nice and convenient. I ordered a few carbon filters last week and I'm going to try chaining one after the ceramic filter to take out organics; if it doesn't have enough pressure, I can extend the tubing to allow for a greater height difference in the siphon. Combined with flocculating the source water before the ceramic if it's particularly contaminated, it should be a killer system, able to take care of almost anything but saltwater. Even the volcanic runoff water that I encountered when hiking in Japan could have been made safe and tasty by including that last step**.

Of course, it's not useful in a "I find myself stranded unexpectedly!" situation.

** Instead of using premade tablets, I have the individual components used in modern flocculant purification tablets. That way I don't have the added chlorine compounds (which I don't need and don't want because of the filter) and can adjust the pH (more aluminum sulfate to lower, more sodium bicarbonate to raise) as needed. Much cheaper, too.

Sounds like the biosands that everyone is so eager about- great for large scale, not so great for small scale (like a family well), and not at all portable.

Oh, and bad water was one of the worst killers of sailors in the Caribbean and on the big treasure routes during the age of sail, don't be so eager about water that is stored in the hope that age will "treat" it.

Very interesting topic.
I have a question. What if I'll use a reverse osmosis desalination device on a contaminated water? I guess it must make any water absolutely clean?

Yes, with a few caveats.

* They take a lot more pressure
* They're a lot more expensive
* Each type of membrane has its own chemical weaknesses -- for example, it may not be compatible with chlorine, or may require a certain pH range, or whatnot. They can be rather sensitive things.

But, when you use them right, they produce nearly 100% pure H2O.