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Water: Purification Methods

Gary, Wilma, Heather and grandchild, Nadia get water from  the creek near their home.

Collecting creek water for purification. (View larger version)

Photograph by National Geographic Channel

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When Lewis and Clark explored the nation’s vast interior in the early 1800s, they actually obtained some of their drinking water directly from the Missouri River. Amazingly, they didn’t do anything to purify it, other than probably leave it sit in barrels so that the silt would drift to the bottom. Today, of course, if you did that, you’d become extremely ill; after a hard rain, the river is filled with all sorts of pollution, including poorly treated sewage overflow from waste water treatment plants. The upshot, for preppers, is that you have to get used to the idea that we no longer live in a pristine world, and even if civilization collapses, it’s not going to revert immediately to its unspoiled state. Thus, whether you resupply from a stream or from rainwater, it’s not safe to drink that water without treating it to remove harmful substances and pathogens that can make you extremely ill.

Fortunately, according to Practical Preppers’ Scott Hunt, water purification is something that preppers can easily accomplish, thanks to a multitude of technologies that are available, ranging from the old standby of boiling water, to ceramic filters and ultraviolet light. As prepper author James Wesley Rawles notes, various purification methods may remove one sort of contaminant or pathogen, but let others slip through. Treating water with chlorine will kill bacteria, but not all viruses, for example, and no filter system is 100 percent effective at removing herbicides and pesticides that may contaminate an open body of water. So if you filter water, you’d be smart to use distillation, ultraviolet sterilization, and/or chemicals as an additional precaution. One how-to manual that gives a detailed rundown on pathogens, contaminants and various methods of water purification is the Handbook to Practical Disaster Preparedness for the Family, by Arthur T. Bradley and several co-authors.

Here are some tips on how to make sure that the water you collect is fit for drinking and other uses.

  • Know Your Water. Huntrecommends testing the water source in advance to determine what sort of microorganisms or contaminants it might contain, so that a prepper can have the right filters to deal with each problem.
  • Master the Easy, Basic Techniques for Killing Bacteria.  Boiling is one of the safest and most effective methods of treating water, according to the Federal Emergency Management Agency. In  a large pot or kettle, bring water to a boil—you’ll notice the bubbling and steam streaming out out the vessel—and keep it there for one minute. (Keep in mind that some of your supply will evaporate, so don’t let it boil too long.) Then let the water cool to a temperature that’s comfortable for drinking. Boiled water will taste better if you re-oxygenate it by pouring the water back and forth between two clean containers. Another way to kill loathsome critters in your water is to treat it with bleach. Use a regular, unscented variety that contains 5.25 to 6 percent sodium hypochlorite, and buy a lot of small bottles, because bleach’s potency diminishes after it’s opened. To treat water, add 16 drops (1/8 of a teaspoon) to a gallon of water, stir and let stand for 30 minutes. Hunt notes that  ceramic filters provide good protection against bacteria, and they don’t require any energy expenditure—just gravity. “You just dump the water in the top, and it filters down,” Hunt explains. “The bacteria can’t get through the top.
  • Use Distillation to Get Rid of Really Nasty Stuff.  Distilling water will remove microorganisms that somehow survive bleach, boiling, and other methods. In addition, it will remove heavy metals, salts, and other chemical pollutants that can harm your health. Basically, the process involves boiling water so that it leaves behind all the stuff that has contaminated it, and then collecting the vapor and allowing it to condense back into liquid water. You can create a simple distilling apparatus simply by suspending a cup by attaching it to the inside of a large pot’s lid, and then putting a layer of water in the bottom of pot and boiling it for 20 minutes. As the pot cools afterward, the water that drips down into the cup is purified. If you’re concerned about using up fuel, it’s also possible to build a solar energy-powered distiller. Here are some simple instructions on that from a prepper blogger.
  • Get an Ultraviolet Light.  Large water treatment facilities have used ultraviolet radiation to kill pathogens for years, but small portable units for use in the home or out in the wild have only recently become available. Basically, an ultraviolet purifying unit is a bottle with a small light source that’s inserted into the water. After 30 to 80 seconds, the radiation kills most microbes. Ultraviolet treatment won’t remove impurities such as dirt, metals or chemicals from the water, however, so you’ll have to combine it with another method to get really clean water.

If You Only Do Three Things:

  • Get a Basic Ceramic Filter.  This is the lazy man’s way to get rid of bacteria, but Hunt says it’s pretty effective.
  • Stock Up on Bleach. It’s great for killing microorganisms that can may you really sick.
  • Boiling Water is a Really Easy, Quick Method of Purification.  You can bring a pot or kettle of water to a boil and keep it rolling for a minute, let it cool, and you’re pretty safe from bacteria.


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30 comments
Pf Wag
Pf Wag

BEST low cost solutions:

Get some water purification tablets.  Camping and outdoor goods stores like REI carry them.

For purifying a LITTLE more water for a few days: get a  Katdyn water filter and some water purification tablets.  www.katadyn.com


One step up for more water is a candle cartridge, gravity filter, like the Berkley.  ALSO have some chlorine or water purification tablets for killing any virus that may be contaminating the water


Moving up, get a good carbon block filter AND some chlorine or water purification tablets.

Best place I know of: www.premium-water-filters.com for any filters (and specialty filters like for removing fluoride). Check out their Emergency Filters.  Much cheaper than the Berkley and will generate more clean water faster.


FYI: I have no association with any of the above.



Pf Wag
Pf Wag

I forgot to mention the very hot water kills crypto 99% of all open raw water sources in the USA are contaminated with crypto and/or the not quite so bad pathogen Giardia.  Both are easy to kill with chlorine or heat but their eggs, the cysts, are much tough to kill. They are, however, easy to filter out.



Pf Wag
Pf Wag

The part about boiling the water, roiling boil for one minute etc is all BS. All pathogens are killed by heat and its a temp X time thing.  Milk is pasteurized at 71.5 °C (160 °F) to 74 °C (165 °F), for 15 to 30 seconds. Get the water temp up close to 200F and noting outside of some bacteria that live in Yellowstone's hot pools survive.  So when heating the water, by the time a decent size bubble pops the surface, the water is sterilized. At this point its more important to cover the pot so the stuff floating around in the air doesn't fall into the cooling water and contaminate it. BTW, boiling not only does not take out harmful chemicals that may be in the water but it concentrates them.


Neither a ceramic or solid block charcoal filter will filter out a virus. Use chlorine (UNSCENTED Clorox) to KILL those.  The 30 minutes is right as it is also a concentration X time thing.  HOWEVER, some nasty pathogens like cryptosporidium will survive for an hour in pure Clorox. 


And the 16 drops of "unscented Clorox" in a gallon of water is wrong too.  The chlorine in Clorox decays with time and after a year its only half as strong. It is also absorbed by organic compounds in the water (in the process, creating a cancer causing chemical....).  Ideally your water should be chlorinated to a level of about 5-10ppm of chlorine. So how do you know that?  You can buy some chlorine test strips that they use for swimming pools.  OR, add 4 drops, stir and wait ten minutes.  If the water doesn't have a SLIGHT chlorine smell, add a few more drops and repeat the procedure untilo it does.


Rather than using Clorox (sodium hypochlorite) get some calcium hypochlorite.  Same stuff they use to chlorinate swimming pools. A piece the size of this . (period) treats 1G of water.  I pound will treat something like 10,000 gallons and it doesn't degrade.  HOWEVER, the stuff is not play dough so read the precautions, handle it carefully (including using a dust mask and googles) and NEVER allow organic compounds to get in it (it could explode) and only store it in an ALL PLASTIC container outside of your house.


Oh, and a solid block carbon filter will take the chlorine (and all the other secondary compounds formed) out of the water.



Lars Melger
Lars Melger

Are there any down sides to getting a UV light? I've tried to go off the grid yet make sure my water is pure and clean when I drink it. We tried iodine, but it made the water taste funny and I'm not one to enjoy the funny tasting water. We've got a good filtration system, but we want to make sure it's sterile. 

http://ecowaterofindiana.com/products.php 

Brian Schwab
Brian Schwab

Water pollution is really a serious problem in the world. And I hate the bad smell and taste of my tap water. Chemicals are added in the tap water to kill waterborne disease. Therefore, I installed a <a href="http://bestreverseosmosissystem.net/">reverse osmosis system</a> to purify my water.

Brian Schwab

Aishaa Karam
Aishaa Karam

Hello....How could we use water Purification methods with low cost at big processes?

Derek Sharpie
Derek Sharpie

I love reading blogs and articles regarding to water treatment purification. Good thing i stumbled in your article. I am currently using berkey water filter and i love it. Very ideal to carry on outdoor trips as it can easily and instantly purifies any water so it ca be safe to drink and also ideal for home use to ensure your family's safe water intake/consumption.

James K.
James K.

I am an Chemist with many years of water treatment experience.

I have recently won the American Chemical Societies Presidential award for my water treatment system.

I have just finished the ACS Entrepreneurial Training and business plan as part of the award.

I can customize the system to match the needs of your potential water source and/or treat reused water too.

What makes my system special is that all components are available as off the shelf/catalog parts.

However, there is and will be some basic skills/training to maintain the system.

Which I figure all Preppers have or need to have.

I am currently building my prototype and inquiring about interest form the Prepper community.

Thank You 

Deyajaira Flores
Deyajaira Flores

Boiling water has always worked for my family......it an inexpensive water filter. 

Lant Vant
Lant Vant

Are there ways of removing radioactive toxins from water like cesium 137 for example?


-Thanks


jerry brazile
jerry brazile

what could a person do to make his or hers own filtration system

jerry brazile
jerry brazile

what type of homemade filtering device could be made

Chloe Harris
Chloe Harris

I recommend that everyone install whole house water filters in order to have clean water. I had the Sanitech Pro-Line system installed by Clear Water Concepts and I have seen a reduction in my water bill, plus my water is clean and so delicious! I don’t have to be concerned about chlorine or other yucky chemicals, which is great.

Anthony Urso
Anthony Urso

You can make charcoal from a campfire, cut the bottom off a 2 liter plastic soda bottle, layer charcoal & sand (to keep the charcoal from floating to the top). Hang upside down and use as filter http://bit.ly/14trFKD

Anthony Urso
Anthony Urso

You can make charcoal from a campfire, cut the bottom off a 2 liter plastic soda bottle, layer charcoal & sand (to keep the charcoal from floating to the top). Hang upside down and use as filter http://bit.ly/14trFKD

Pf Wag
Pf Wag

Yeh, you need power so make sure you have back up for how long you think the power will be out for and they don't filter out other contaminants unless they are coupled with a carbon block filter which needs water pressure to push the water through the filter.. 

A solid carbon block filter will filter out chlorine.  I don't know about Iodine.

Pf Wag
Pf Wag

Good but it needs pressure, and wastes water.  And if the membrane ever ruptures or leaks you'll contaminate the "fresh" water. Murphy's Law says.....

Pf Wag
Pf Wag

The emergency one from www.premium-water-filters.com is cheaper and delivers more filtered water.  The reason is that the raw water source is a bucket located higher.  More gravity created water pressure to push the water through the filter.  BTW, don't forget the chlorine. 

Pf Wag
Pf Wag

doesn't take out the virus, you know like Bird Flu (H5N1) carried by ducks and geese who crap in the water.

Hannah Tess
Hannah Tess

@Derek Sharpie  invest on a good home water purification system. it will benefit your family's health and safety. Reverse Osmosis water system is really the best as it can remove contaminants such as arsenic, nitrates, sodium, copper and lead, some organic chemicals, and the municipal additive fluoride.

Pf Wag
Pf Wag

Yeh but if the power is out you can't boil your water if you rely on electricity.  And if the power is out too long, so will the natural gas be.

Pf Wag
Pf Wag

Reverse osmosis and distillation takes everything out.  Depending on the size of cesium 137, you might be able to filter it out with a really tight solid carbon block filter. When you know the size, you'd look for a carbon filter with a smaller absolute filter size.

Pf Wag
Pf Wag

see the ink I posted above.

Pf Wag
Pf Wag

Sand filter.  Google it. Still need to use some chlorine product though to kill virus.

Pf Wag
Pf Wag

Actually what you have to be concerned about is a failure in your local and mostly automated water treatment plant.  By the time they say "boil your water" it's too late.  

Google  milwaukee + cryptosporidium

Pf Wag
Pf Wag

It will clean up the taste but there are too many channels for contaminated water to pass through.  Ditto for granulated charcoal filters.