Water Purification: 4 Things You Must Know...

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by M.D. Creekmore: Favorite
Survival Books



Water Purification
Options – Non-Fiction
Writing Contest Submission
by D. Holden


Water: the
source of life. One can live weeks without food, but only days without
water. Water makes up approximately 60–70% of a human’s
body weight. It is, and should be, one of the most important considerations
in planning for a long-term disaster scenario. Given that the average
human will need one gallon per person per day minimum, storage of
large quantities of water quickly becomes impractical and therefore
won’t be discussed in this post. This article also assumes
that you don’t have a private well that is completely off the
grid. If you have the land, if the city or county allows it, and
if you can afford it, then by all means, make getting a private
well your first order of business!

So how can
one find safe water after a major disaster? If you don’t have
a well with a solar or hand pump, you’ll most likely have to
rely on natural sources of water such as streams, ponds, lakes,
or rivers. It would still be quite dangerous to drink directly from
stream or river, even if it appears completely clean and clear.
There is always the risk from Giardia and Cryptosporidium, not to
mention the chance of a dead animal just upstream unbeknownst to
you. Even a bit of animal or human excrement upstream can make a
person seriously or deathly ill. If you use natural sources of water,
then some form of filtration or purification will be necessary.

So, what to
do? Well, you have a few options:

1. Filters

First, you
could invest in a ceramic filter, like the British
Berkefeld Ceramic Water Filter
. While a bit pricey, they’re
both highly recommended and receive terrific reviews. I’ve
used this particular brand in West Africa for many years, and I
admit they are convenient, safe, effective, easy to maintain, and
long-lasting. The ceramic filters only need an occasional cleaning
and can withstand cleaning many times before needing to be replaced.

They are definitely
worth the money, but you should note that they only filter out organic
contaminants and sediment from water. Since they don’t have
anything like activated charcoal, they don’t filter out chemical
contaminants. I don’t imagine most sources of water would contain
dangerous levels of chemicals, but if you take water from a river
or stream that is next to a typical commercial farm, there is the
risk of ingesting pesticides and herbicides from the farm runoff.
It’s the same for water that near an industrial plant. This
should not be a problem for most people, but it is good to be aware
of the possibilities. Know what is upstream!

For a good
portable filter, you could go with the Swiss-made Katadyn
or the Hiker
. A wonderful benefit to these filters is that they are extremely
portable, which makes them vital components of bug-out bags. Another
benefit is that they remove virtually all organic and chemical contaminants.

The down side
is that you only get about 200 gallons out of each filter, and the
replacements add up very quickly. However, if you want more filtration
for your money, like say 13,000 gallons worth, you can go with the
Pocket Water Microfilter
. While remaining very portable, it
uses a simple ceramic candle similar to the British Berkefeld. Just
note that as with all ceramic candles, it won’t filter out
chemical contaminants.

An interesting,
albeit more primitive option, is to build a BioSand
. They’re not perfect, but they are so rugged and
easy to build and maintain that they are worth some consideration.
They remove around 95% – 99% of all organic contaminants by
way of an active “biological layer” and simple sand filtration.

These filters
have largely been implemented in the humanitarian realm by organizations
such as Samaritan’s Purse and Convoy of Hope. You can build
them out of plastic or concrete, and they’re very low maintenance.
Again, they don’t remove 100% of organic contaminates, so there’s
still a very small chance of getting a water-borne bug of some kind,
but it’s a good semi-permanent solution when your other options
run out.

Since the biological
layer takes some time to develop, you could use other short-term
methods listed here to carry you over until this filter is fully
functioning. They really do save lives in the third-world, so it’s
worth some investigation, at least for a backup option. You can
find plans online for building them.

2. Boiling

always the idea of boiling your water, but for that you would need
a large source of energy, perhaps something like wood or propane,
not to mention a large amount of time as well as storage. Boiling
water may work in a pinch, but it would be extremely cost and resource
prohibitive in the long run, especially in a long-term grid down

On a personal
note, many years ago, I went on a weekend camping trip and severely
underestimated my water demands, all while carrying foods high in
sodium. Needless to say, I became very dehydrated and had to stay
up all night boiling, cooling, and drinking river-water. It worked
great, but due to the time and the energy necessary to boil water,
I quickly realized that relying on this method of water purification
in the long-term is not a good idea.

3. Chemical
Disinfection (i.e. Chlorination)

In a common
local disaster scenario (hurricane, ice storm, tornado, etc), organizations
such as FEMA and the Red Cross suggest using unscented household
bleach (5.25 to 6.0 percent sodium hypochlorite) to treat water.
FEMAs instructions are as follows:

“Add 16
drops (1/8 teaspoon) of bleach per gallon of water, stir, and let
stand for 30 minutes. The water should have a slight bleach odor.
If it doesn’t, then repeat the dosage and let stand another
15 minutes. If it still does not smell of chlorine, discard it and
find another source of water.”

This method
is not really generally recommended for long-term use. Plus, bleach
has a limited shelf-life (around 6 to 9 months), so you’d have
to rotate your supply often in a long-term disaster. To get around
this limit, some people instead buy calcium hypochlorite (rather
than the sodium hypochlorite in bleach) in the form of “pool
shock.” It comes in granular form, is relatively stable, and
has a surprisingly long shelf-life.

I’d be
careful with this stuff however, as storage can be dicey (I’ve
heard stories of it corroding surrounding items when not stored
properly), and one needs to be aware of proper measurements and
mixing amounts. I’m sure with enough research and preparation,
the granular calcium hypochlorite could be a fairly good backup
method of water purification.

4. Solar
Disinfection: SODIS

SODIS, or SOlar
DISinfection, is the cheapest and easiest of the methods listed
here. Solar disinfection only requires two things: clear plastic
(PET) bottles and sunlight. Find soda or water bottles with the
PET recycling mark that are clear and colorless, 2 liters or less
in volume, and preferably no more than 4 inches in diameter. Fill
them with water, close the cap, and lay them on their sides in full
and direct sunlight for a day.

It’s better
if you place them on a shiny surface, such as corrugated metal roofing,
and angle them towards the sun so that they sun’s rays will
strike the bottles more directly. If the water is cloudy or turbid,
filter the water with cloth or cotton until it is clear. Keep the
bottles in direct sunlight for at least 6 hours. If the sky is cloudy,
you will need to keep the bottles out for two days.

So, how does
it work? The strong ultraviolet light (UV-A) from the sun not only
destroys bacteria directly, but it also reacts with oxygen to create
oxygen free-radicals which can also kill bacteria. One way to improve
the effectiveness of the process is to aerate the water by shaking
it. To do this, fill the bottle 3/4 full, cap it off and shake it.
Then fill the bottle up the rest of the way until it’s completely
full. This oxygenates the water and increases the amount of oxygen
free-radicals created by the sunlight.


This is surely
not an exhaustive list of water treatment methods, but I wanted
to list some common ones for consideration. Rather than rely solely
on one method of water purification, I would consider having many
methods in one’s survival
arsenal. So goes the preparedness maxim, “two is one and one
is none.” This definitely applies to methods and ideas as well.

Do you have
any other methods not considered here? What do you think?

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20, 2010

Creekmore [send
him mail
] is a full-time blogger and preparedness consultant.
He currently lives completely off-grid somewhere in the Appalachian
mountains and is currently working on his upcoming book The
Dirt Cheap Survival Retreat for Paladin Press. To connect with
M.D. Creekmore please visit his Survival

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