Filtering water with a Katadyn water filtration systemIf the water you find is also muddy, stagnant, and foul-smelling, you can clear the water before purifying it.  Filtration removes the large, undesirable particles such as dirt and plant particles.  You can filter water by:

  • By placing it in a container and letting it stand for 12 hours to settle the large particles.
  • By pouring it through a filtering system to filter the large particles.

NOTE: The filtration procedure only clears the water and makes it more palatable. You will have to purify it to ensure it is safe to drink.

Making a Filtration System

To make a filtering system, first make a tube out of a hollow log, bamboo, or the leg out of a pair of jeans.  Add a loose fitting rock to each end.  Try to find an irregular-shaped rock that fist tight enough to stay in place but does not seal the ends up.  Add a filtering layer about an inch or two deep using filtering material such as sand, crushed rock, charcoal, or cloth.  Add several layers of each type of material.  Using charcoal from a fire will help remove odor.  Charcoal is also helpful in absorbing some agricultural and industrial chemicals. Pour the water through the tube and collect the filtered water at the other end.  The first few gallons may be murky but will clear up after a few more gallons have passed through.  Let the filtered water stand for 45 minutes before drinking it.

You can also pour water through coffee filters to filter out impurities.  If you are using a portable filtration system, you can also “pre-filter” the water though a coffee filter (placed over the intake pre-filter of the filtration system) before pouring it into your filtration system.  This will extend the life of your portable filtration system.

Commercial Filtration Systems

A portable, Katadyn water filtration systemThere are many portable filtration systems on the market today.  These systems filter the water via microfilters.  Many use ceramic filters that purify the water too and rid the water of harmful bacteria, protozoa, and pathogens.  Some have charcoal filters too that improve the taste of the water.

The ceramic filters in these systems can filter particle as small as .2 or .3 micrometers but cannot filter viruses and some bacteria which are too small to be filtered.  In cases like this, further treatment with ultraviolet light or chemicals is needed after filtration.