1. Water to drink COULTER

2. Water quality  Water quality- is a measurement of the substances in water besides water molecules.  Certain substances, such as iron, can affect the taste or color of water but are harmless unless present at very high levels.  Other substances, such as certain chemicals or microorganisms, can be harmful to your health

3. Water quality cont.  Concentration- is the amount of one substance in a certain volume of another substance.

4. Acidity  The pH level of water also affects its quality.  pH- a measurement of how acidic or basic the water is. (on a scale 0 to 14)  Pure water has a pH of 7 (it is neutral- neither an acid or a base)  The higher the pH, the more basic the water  The lower the pH, the more acidic the water

5. Hardness  Hardness- The combination level of two minerals, calcium and magnesium, in a sample of water.  Hard water contains high levels of calcium and magnesium.  Main drawbacks:  It does not form suds well when mixed with soap  Clogs pipes and machinery

6. Soft water  Contains lower levels of calcium and magnesium.  Leaves fewer deposits  Forms better soapsuds

7. Disease-causing organisms  These organisms can be detected by a COLIFORM count.  Coliform bacteria are found in human and animal wastes. Their presence in water shows that it contains waste material. a high coliform count shows that the water may also contain other disease-causing organisms.

8. What’s in our water? Selected Water-Quality Standards SubstancesLimit Arsenic0.01 parts per million (ppm) Carbon tetrachloride0.0005 ppm Copper1.3 ppm Cyanide0.2 ppm Lead0.015 ppm Coliform countNor more that 5% of samples taken in a month can be positive pH6.5-8.5

9. Treating drinking water  Water from both public and private supplies often needs some treatment to ensure that it is clean and safe to drink

10. 7 steps to clean water!!!  1. treating water from lake/river requires filtration (passing water through screens that allow the water through but not debris)  2. chemical is added to cause sticky globs, called flocs, to form. Other particles stick to the flocs known as coagulation.  3. the heavy clumps then sink into the settling basins.  4. The water is filtered again.  5. chlorinate the water (kills disease-causing microorganisms) at this point ready to distribute to homes.  6. air is forced through the water. This process reduces unpleasant smell and taste.  7. minerals added to soften or other purposes.