1. Water to drink Coulter

2. Water quality 0 Water quality- is a measurement of the substances in water besides water molecules. 0 Certain substances, such as iron, can affect the taste or color of water but are harmless unless present at very high levels. 0 Other substances, such as certain chemicals or microorganisms, can be harmful to your health

3. Water quality cont. 0 Concentration- is the amount of one substance in a certain volume of another substance.

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

5. South Africa acid water Risk contamination of human consumable water if not cleaned up. Acid water seeping from shuttered gold mines is rising. Iron disulfide, the “fool’s gold” found in left- over rocks from gold mining, combines with rainwater to form sulfuric acid and other chemicals.

6. Hardness 0 Hardness- The combination level of two minerals, calcium and magnesium, in a sample of water. 0 Hard water contains high levels of calcium and magnesium. 0 Main drawbacks: 0 It does not form suds well when mixed with soap 0 Clogs pipes and machinery

7. Soft water 0 Contains lower levels of calcium and magnesium. 0 Leaves fewer deposits 0 Forms better soapsuds

8. Disease-causing organisms 0 These organisms can be detected by a COLIFORM count. 0 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.

9. 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

10. Treating drinking water 0 Water from both public and private supplies often needs some treatment to ensure that it is clean and safe to drink

11. 7 steps to clean water!!! 0 1. treating water from lake/river requires filtration (passing water through screens that allow the water through but not debris) 0 2. chemical is added to cause sticky globs, called flocs, to form. Other particles stick to the flocs known as coagulation. 0 3. the heavy clumps then sink into the settling basins. 0 4. The water is filtered again. 0 5. chlorinate the water (kills disease-causing microorganisms) at this point ready to distribute to homes. 0 6. air is forced through the water. This process reduces unpleasant smell and taste. 0 7. minerals added to soften or other purposes.