Filtering Water
Background Information:


Many different foreign materials and contaminates make their way into our waterways. In developing countries, the absence of a water treatment infrastructure poses great danger to the people and to the ecosystem. in this activity, we are going to add different pollutants to our water and experience the ease or difficulty in removing these items by using different kinds of filters.

Thinking Out of the Box...

Bangladesh: Old saris are the key to cleaner, safer water
Source: SPLASH! Newsletter, WaterYear 2003

The number of cholera cases in remote Bangladeshi villages was halved when local women poured drinking water, collected from rivers and ponds, through their old saris. The folded saris trapped more than 99 percent of the cholera causing bacteria which, although tiny, attached itself to plankton to big to squeeze through the pores in the fabric. Tens of thousands of people die every year from dehydration causes by cholera induced diarrhoea and many lives could be saved by filtering water in this way.

Procedure
  • Fill the jar more than haflway with water.
  • Add the miscellaneous small items: shredded paper, iron filings and food coloring.
  • Let the mixture sit for a while, allowing the pollutants to settle in.
  • Wave the magnet around under water.
  • Next hold the strainer over the second jar and pour the contents from one jar into the other, passing through the strainer.
  • Notice, what came out and what is left in the water.
  • With one more try, attach the coffee filter or paper towel to the top of the jar and pour the water through one more time.
  • Use other household items to filter water, such as play sand and charcoal.
Materials:
2 large clear plastic jars
Water
Liquid food coloring
Basket coffee filter
Strainer
Shredded paper
Iron Filings (if available)
Magnet (if available)
Misc. small items

Observation and Discussion:
* Does the water return to normal? Is it clear or do stubborn contaminates stay behind?

* Different methods of filtration will remove different pollutants from the water. (i.e. Magnet for the iron filings and larger filter pores for larger items, etc.) Learn more and talk about applications of filtration systems in your waterways.

* How is sewage treatment handled in your area? Is there a treatment plant nearby? If so, go and visit it.

* Compare and contrast the means of sanitation in areas of the world.

* Talk about how easy or difficult it is to get certain contaminants out of the water.

Learn about Water, Sanitation, and Hygiene by visiting http://www.unicef.org/wes/index.html
or the WASH campaign:
http://www.waternunc.com/gb/w2s2c06_2002/

Source: "Every Body Counts, Every Drop Matters". United NAtions Classroom Resource Guide on Water