1. Water Pollutants and uses

2. Water • H20 • 75% of • 98% is • Less than 1% of • Glaciers hold most of the

3. Water • Used to help create • Tundra • Taiga (Pines)

4. Water • Deciduous Forest • Tropical Rainforest

5. Water • Grassland • Desert

6. Water cycle

7. Water uses

8. Water sources

9. Drinking water (U.S.)

10. Drinking water (Africa)

11. Water pollutants • In 1974, Congress passed the • This law requires EPA to determine safe levels of chemicals in drinking water which do or .

12. Nitrates • (NO3)-1 • The MCLG for nitrates has been set at 10 parts per million (ppm), and for nitrites at 1 ppm • EPA believes this level of protection would not cause any of the

15. Nitrate • What are the health effects? • Short-term: Excessive levels have caused . • The serious illness in infants • Conversion of nitrate to nitrite by the body, which can interfere with the • Symptoms include shortness of breath and .

16. Nitrates

17. Nitrates • Long-term: Nitrates and nitrites have the potential to cause the following effects from a lifetime exposure at levels above the MCL: • Diuresis  • Starchy deposits • Hemorrhage of spleen

18. Phosphate • (PO4)-3 • This element is required for the • Used in the manufacture of proteins in • Phosphorus is essential for

20. pH • The indicator for acid, or base is known as the pH value. • A pH value of 7 means a • The lower value (1-6) indicates . • A higher value (8-14) is a sign of a .

21. pH • Apple Juice - 3 • Orange Juice - 3.5 • Coffee - 5.5 • Milk - 6.2 • Baking Soda - 8.5 • Soapy water - 10 • Bleach - 12

23. pH • Ideal pH level of drinking water should be between, • The human body maintains pH equilibrium on a constant basis and will not be affected by . • Our stomachs have a naturally low pH level of 2 which is a beneficial acidity that helps us with .

24. Dissolved Oxygen • A high DO level in a community water supply is good because it makes • High DO levels speed up • Industries use water with the least possible amount of .

25. Dissolve Oxygen

26. Dissolved oxygen • The amount of dissolved oxygen often determines the number and types of organisms . • Fish like trout are sensitive to low DO levels (less than eight ppm) and cannot survive in warm,

27. Dissolved Oxygen

28. Dissolved Oxygen • Decay of organic material in water caused by either chemical processes or microbial action on untreated sewage will • Dead vegetation can severely • This is the most common cause of fish kills, especially in summer months when .

30. Silica • The silica content of water ranges from a few ppm in surface supplies to well over 100 ppm in certain well waters. • In water treatment, we are concerned with silica because of its capacity to form . • In its colloidal (suspended) form it consists of very .

31. Silica

32. Silica • Silica Removal Processes: • Filtration • Chemical precipitation • Reverse Osmosis • Strong base and ion exchange

33. Filtration (simple)

34. Filtration (Advanced)

35. Precipitation

36. Ion exchange

37. Reverse Osmosis • The solute is retained on the • The pure solvent is allowed to • This membrane should not allow large molecules or , • Smaller components of the solution

39. silica • When complete silica removal is required, various combinations . • RO systems are currently unable to • RO is far better at removing various forms of non-reactive silica and will remove many additional contaminants

40. CO2 • Rainwater is slightly acid and will absorb additional amounts of carbon dioxide if it . • During process • If the water now passes through limestone formations, its carbonic acid content will react with the limestone to form soluble calcium bicarbonate. .

41. CO2 • If the water now passes through limestone formations, its carbonic acid content will react with the limestone to form . • In this process the

43. CO2 • If nature or chemical agents do not neutralize carbonic acid, it will cause . • In those parts of the country where the problem is prevalent it can lead to

45. CO2 • Carbon dioxide, with carbonic acid, is primarily a problem in water containing relatively . • In such water there are not sufficient . • Alkaline salts or basic salts are salts which are the product of the neutralization of a .

46. Hardness • Hard water is water with a high mineral content, • It is not necessarily harmful to our health • Hard water poses a threat on appliances because it forms a scale which is an

47. Hardness • When this scale builds up • Decrease in water pressure and • In Northeast MN,

50. hardness • Hard water • When these ions react with • This means more soap will be used in the process of . • It also means the