What many poor people, backcountry hikers, and those living in remote areas have in common are a reliance on untreated, local sources of water that may be contaminated, and must be purified before it can be safely consumed. There are two basic approaches to water purification: using a reverse osmosis filter, or a tag team of two methods working together to eliminate two separate contaminants.

1. Methods for Water
Purification

2. What many poor people, backcountry hikers, and those living
in remote areas have in common are a reliance on untreated,
local sources of water that may be contaminated, and must be
purified before it can be safely consumed. There are two basic
approaches to water purification: using a reverse osmosis filter,
or a tag team of two methods working together to eliminate
two separate contaminants.

3. A reverse osmosis filter is the do-it-all of water purification. The
process is the only one that addresses both harmful
microorganisms and pollutants at the same time. It works by
forcing water under pressure through a membrane made of thin
film composite, with a inner matrix of dense polymers. The
result leaves purified water on one side of the membrane, and
contaminants on the other side. The technology is reliable, but
expensive and relatively cumbersome, and requires electricity
to work. It is therefore a sound choice for use in fixed positions
or by those who can afford to tow a small trailer with a small
electrical generator around, but anyone on the move or without
access to electricity needs to use other methods.
Reverse Osmosis Filters

4. The first part of the
purification tag team must
eliminate microorganisms, like
harmful bacteria and parasites.
There are a handful of tried
and true methods for doing
this. The most familiar is
boiling. Simply bringing water
up to its boiling point of 212
degrees Fahrenheit will kill
almost all microorganisms, so
just a few minutes of boiling
will do the job.
Microorganisms

5. The other options involve
chemical agents. Hikers have
long been familiar with using
iodine tablets to kill
microorganisms in local water
sources. A typical example would
be a tiny pellet being good for a
quart of water. Bleach has been
popular in poorer countries for
decades as a means of killing
microorganisms in local tap
water, and works just as well with
other sources. Eight drops per
gallon will make the water safe to
drink. Both methods should be
allowed half an hour to do their
job.

6. The other half of the tag team is to eliminate pollutants. The
best way to do this is with a homemade carbon filter. This uses
the same technology as Brita filters. Carbon is a chemically
active substance, with a tendency to bind to most anything. At
a microscopic level, charcoal is a heavily pitted and striated
material, which vastly increases its real surface area. The result
is that when water slowly runs over charcoal, pollutants find
themselves glued to the charcoal surface. An improvised filter
can be made out of ground-up charcoal, a strainer and a funnel.
Bear Gryllis made a purification drinking straw out of little
more than a reed and some charcoal bits for the Discovery
Channel's "Man vs. Wild." It's a simple technique, but it is
highly effective.
Carbon Filtration

7. A solar still can be built by digging a hole, putting an empty
pan in the bottom, setting a bucket full of impure water into
the middle of the pan, and then setting a peaked clear plastic
sheet over top. This will evaporate the water out of the
impurities, collect and condense it inside the plastic, and let it
drip down into the empty pan. The problem with this method is
that it is very slow and produces relatively little water.
Solar Distillation
There is another method
that produces fully
purified water in one
step, and that is
distillation.

8. Article Source: Ehow.Com
Image Source: WaterFilterWorld.Com.AU