Mar302012
INSTANT SURVIVAL TIP: Improvised Water Filter
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PDFBy John A. Heatherly, Author of The Survival Template
photo from AFR 64-4, Figure 19-15, page 189
A variety of events can contaminate ordinary, working sources of water. For example, rainstorms, or even worse, hurricanes, can pollute tap-water that is normally clean. In other cases, a pond or puddle may be used as a water source. With a little improvisation these problems can be remedied, allowing for better-tasting, better-smelling water. NOTE: This type of filter will NOT purify water, but is meant to be used in conjunction with a purification method (boiling, iodine, bleach, etc ….)
The figure above illustrates a three-stage water filter built out of a tripod and porous cloth. This simple device is highly effective in cleansing drinking water. I have seen a version of this constructed out of a plastic milk jug that washed up on the beach (a large, plastic soda bottle would work as well.) In this case, the bottom of jug was removed with a knife and a piece of cloth was placed over the jug’s mouth. The inner layers of the filter were the same as in the image: charcoal, sand, and grass.
Projects such as this water filter can also make for great fun on family outings and camping trips. Again, ensure that the water is PURIFIED before drinking it, and experiment with filters such as this one to improve the look and taste.
Anyone have experience with filters similar to this one?
© 2012, John A. Heatherly. All rights reserved.
(18) Readers Comments
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Space-Saving and Effective Sub-Irrigated Planters (SIPS)
Mosquitos are definitely an issue with this type of design. There are
Space-Saving and Effective Sub-Irrigated Planters (SIPS)
mine has a watering tube running up the inside wall of the pot, which
Space-Saving and Effective Sub-Irrigated Planters (SIPS)
How do you control for mosquitos breeding in the stagnant water at the
Midge
This idea works well with buckets as well. Punch small holes in the bottom of stackable buckets. Place one filter element in each bucket. Stack them on top of the the clean empty bucket. Gently pour water into the top one. Bottom one only needs boiling to kill microbes to finish the job.
Amiee
that sounds like an even easier idea
Hugh Davis
Instead of grass (which might already have impurities and/or eggs laid on the blades of grass) try to use loosely woven cloth or fine gravel/coarse sand. I’ve also seen these set up using 55 gallon drums and a running stream. First barrel water came in the top and then out a few inches above the bottom into the top of the next barrel etc. First filter (grass in the above) was alternating layers of cloth and wood ash. Yes this is how you extract lye. But it also works to kill off most of the beasties in the water and is removed by the charcoal layer. Take the charcoal out and bake it to reactivate it.
John A. Heatherly
Midge and Hugh – thanks to both of you – I have never tried either of these similar methods.
Hugh – do you happen to know to what degree the “beasties” are killed using this method? Sounds awesome.
Justin
We made one similar way back in High School Biology class. We used medium sized rock, pea gravel, sand, and then charcoal. We gathered water from a mud puddle behind the building, ran it through the filter, and then boiled it with the bunsen burners in the lab. The water was a little flat, but otherwise fine. And I wasn’t the only kid tasting the water…
Kay_Skip
As a science experiment, my daughter used a 2 litre bottle as described above. She filled it with pea gravel instead of grass and then sand and lastly she used charcoal. After running the murky water through the homemade filter, we had to do it a 2nd time. We then dropped one drop of Iodine in the glass of water, came back and drank it a couple of hours later. It was ok and didnt make me sick.
Eve
I have a question- the charcoal…can you use just regular charcoal like you buy for grilling with? Do you have to break it up or can you just use the briquettes as they are bought? Sorry for sounding ignorant but I’m learning. Thanks.
John A. Heatherly
Hi Eve, great question, and no worries – I am still learning too! With an interest in wilderness survival, I have always scraped charcoal from logs in the fire-pit. Now knowing the chemical make-up of some of the commercial stuff, I have never tried it for this purpose, and would be hesitant to do so.
Heather
How small should the pieces of chracoal be? Big chucks or small, or grain size?
John A. Heatherly
Heather – Big or small chunks will work, as long as the filter contains enough charcoal for the water to pass through rather than around it while running down to the other layers.
SilentNightPrepper
I used to put a single briquette in a sock and put it on some poster-board (on top concrete slab) and beat it with a hammer. The coal comes through in a fine dust. Collect and use, then I realized I could just collect it from firewood lol.
momengineer
Be sure that if you do..you are using “plain” charcoal…NOT The “easy light” stuff…it contains chemicals to help it light, that will leach off into your water
Zort
the smaller the bits of charcoal are, the greater the surface area, and the more effective the reaction.
i suggest you crush the briquettes if you want the filter to work at it’s best.
Jeff Hoverson
Thanks. How many gallons of water would you recommend before changing the filtering elements.\ Especially the charcoal.
jh
Jan
What a great idea. My husband said he made something similiar in junior high ROTC. This is an easy thing to try out this summer when we are camping.
Jeff
I would not use commercial charcoal, because the commercial version often has additives to aid in lighting. I would use charcoal from a fire that I lit and make sure the wood was only from trees, not lumber from building sites. This lumber may have lead or other contaminants.
Dave
Splurged and got a Katadyn pocket water filter. A bit on the pricey side, but it will filter contaminants from 13,000 gal. of lake / pond water. The Katadyn is fairly small and extremely well made – easily fits in your BOB.To improve taste, I would then jerryrig up a charcoal filter or a Brita – those are fairly cheap.
That’s right – 13,000 gal. of water.
Sean P
My home based setup for “Bug In” is very similar, its a gravity fed system that uses a a 5 gallon bucket that is 1/3 charcoal (all natural charwood made locally by a small company here in my home town, aimed at people who grill but don’t want the chemicals of briquettes) on the bottom, 1/3 fine grain beach sand that has been baked at 250 degrees for 3 hours to kill off any critters and/or their eggs in the middle, and 1/3 pea gravel on the top. There is a spigot on the bottom of this bucket with an on/off flow lever, which is attached to a length of aquarium grade tubing. That bucket sits on top of the table on the left side, and the hose runs to the lid of another 5 gallon bucket under the table on the right side (this is done to prevent possible cross contamination if there is a spill while pouring the questionable water). The hose connects to a ceramic filter element in the lid of the catch bucket, which will take care of nasty bugs and viruses (according to manufacturer). If needed, it can be boiled as well, and finally the catch bucket has a spigot with flow control on/off on the bottom for easy access to the clean water.