1. 6

2. Water Use in the United States 50% Agricultural (Irrigating/ Watering Crops) 45% Industrial (Generating power, Mining, Cooling Machinery) 5% Residential/ Household Use (drinking, bathing, flushing toilets)

3. 7

4. 5 Steps of Treating Water Or, do we eventually drink the water that was previously flushed down the toilet?

5. 1 st : Preliminary Treatment Wastewater arrives at the treatment plant and goes through bar screens that take out large debris (like diapers, leaves, and trash)

6. 2 nd : Primary Treatment The wastewater then flows to settling tanks where the bacteria settle out. Primary treatment might remove 90 percent of all solids and organic materials from the wastewater

7. 3 rd : Secondary Treatment This is where the suspended and dissolved materials not taken out by primary treatment are removed. This is where good bacteria eats the organic material and other solids before the water passes through membranes

8. 4 th -Disinfection Water passes through Ultraviolet (UV) light, a high energy part of the Electromagnetic (EM) Spectrum, that kills germs, bacteria, and viruses Chlorine added to the water kills any remaining bacteria, and the water is discharged

9. 5 th Advanced Treatment Uses chemicals to remove phosphorous and nitrogen from the water. After this stage the treated water is released back into lakes, rivers, oceans, etc. Photo courtesy Falke Bruinsma Final clarifierFalke Bruinsma

10. 8

11. V. Water Resource Problems A. Overdraft 1. Occurs when a body of water is drained faster than it is filled; may occur in surface water or groundwater Ex. The Ogallala aquifer is the largest aquifer in the world and supplies water to 8 midwestern states; the water in this aquifer is expected to last only 40 more years

12. 9

13. Potable vs. Unpotable Water Pronounced poe-ta-ble Potable Water is clean water that you can use for drinking or cooking Unpotable Water is dirty water that contains or could contain pollutants, waste, bacteria, dirt. You should not use or drink unpotable water

14. 12

15. Desalination: 1.Reverse Osmosis- pass the water through a membrane to filter out the salt 2.Distillation- heat the water, turn it to steam, leave the salt behind, then condense the steam to water 3.Electrodialysis Reversal- use chemicals and electrical charges to remove the salt

17. 19

18. Biotic Index is a scale for showing the quality of an environment by indicating the types of organisms present in it. It is often used to assess the quality of water in rivers. It is measured from 1 to 10 and corresponds to the four basic water quality (Excellent, Good, Fair or Poor). The concept of the Biotic Index was developed by William M. Beck in an effort to provide a simple measurement of stream pollution and its effects on the biology of the stream To assign a biotic index value to a specific water site, the tester first collects macroinvertebrates from portions of the sample area of the stream, river or lake and separate them into groups of similar-looking organisms. More extensive testing can be done by looking for certain microscopic organisms. Then an identification key is used to help determine which category or group the organism belongs in and allows a numerical value be assigned to that organism. A worksheet is then used to calculate the final value or score of all the organisms found. Depending upon the worksheet's equations, the score determines the condition of the water quality.

19. Biotic Index What is a Biotic Index? A biotic index is a tolerance value of macro invertebrates that measures how much pollution the animal can withstand. Scientists use biotic indices to measure water quality. They do this by counting the number of macro invertebrates with a low biotic index and then count the number of macro invertebrates with a high biotic index and compare the two numbers. This comparison indicates the pollution level of a body of water. If you have more macroinertebrates, you have less pollution If you have fewer macroinvertebrates, you have more pollution

20. 20

21. Bioaccumulation The gradual buildup, over time, of a chemical in a LIVING ORGANISIM For example, when fish are exposed to a lot of mercury (a poisonous chemical), they can’t get rid of it, so they get more and more mercury

22. Bio-magnification Basically, movement of pollution up the food chain As you eat things you are exposed to whatever pollution they had in their bodies (for example, a bird eats a fish, it is exposed to the pollution in the fish)

23. 21

24. 1.Agricultural run-off: contains sediments, pesticides, fertilizers, and plant and animal wastes *This is the biggest source of pollution in North Carolina!

25. 23

26. Eutrophication and Dead Zones: Start to finish 1)Farmers put down too much fertilizer on their crops and precipitation causes it to run off 2)The extra nutrients (from fertilizers) in the water helps algae and water plants to grow and reproduce faster 3)As algae die (they don’t live long), bacteria begins to decompose the remains 4)This bacteria uses dissolved oxygen in the water, causing low oxygen levels in the water 5)Without oxygen in the water, fish die because they cannot breathe Excessive Fertilizer Runoff Algae Bloom Decomposing Algae Low Oxygen Levels Fish Die