1. Water Pollution

2. 71% of earths surface is water
We are made up of about 60 %
Could not survive more than 3 days without water
Only a tiny fraction of all the water is fresh and is poorly managed
Upside though – water is continuously recycled in nature
This only works if we do not saturate the water with pollutants

3. Unevenly distributed to the worlds population

4. Surface Water
Water that flows across the land and into rivers, streams, lakes, wetlands, and estuaries.
Surface runoff – precipitation that does not return to the atmosphere by evaporation or infiltrate the ground
Watershed – region around a river, stream, or lake from which water drains

7. Ground Water
Def – precipitation that infiltrates the ground through voids in the soil and rock
Aquifer – porous, water saturated layers of sand, gravel, or bedrock through which groundwater flows

8. Ogallala Aquifer – one of the worlds largest aquifers
Supplies water to 1/5 of all U.S. irrigated land

9. 1 in 3 people in the world depend on water from aquifers
Natural recharge – aquifers refilled by nature such as rain
Lateral recharge – aquifers refilled by streams
Recharging happen very slow
Use of water from aquifers is known as water mining

11. Water by the numbers
We directly or indirectly use 54% of the worlds surface water
By 2025, it will be up to 70%
It takes:
400,000 liters to produce a car
9000 liters to make 2.2lbs of aluminum
7000 liters to produce 2.2lbs of grain fed beef

12. In the Eastern U.S. water is used more for energy production, cooling, and manufacturing
In the Western U.S. water is used more for agriculture

14. Dams/reservoirs One way to replenish lost water
Purpose – to capture and store runoff and release it when needed
Control floods, generate electricity, and irrigation
There are more than 45,000 large dams in the world

16. Pros Cons Useful for recreation and fishing
Can produce cheap electricity
Downstream flooding is reduced
Provides water for year round irrigation
Cons
Large losses of water due to evaporation
Flooded land destroys forests and croplandsand displaces people

17. Migration and spawning of some fish are disrupted
Down stream cropland is deprived of nutrient rich soil

19. Desalination Def – removing salt from ocean water
Distillation – heating water until it evaporates, leaves the salt behind, and condenses as fresh water
Reverse osmosis – pumps salt water through a membrane at high pressures and separates the salt and water

21. 2 problems
Very costly due to energy use
Desalination produces briny waste water which is water with very high concentrations of salt. This cannot be dumped back in to the sea or on land. Creates an unbalanced environment

22. Treating Raw Water:
Some water does not need to be treated but some will have to be
The process includes:
1. Flocculation/sedimentation = This is when a substance called alum is used so the sediment will coagulate. When coagulated, these particles will settle to the bottom of the water.

23. 2. Filtration – clarified water and enhances disinfection
3. Adsorption – Activated carbon is used to get rid of unwanted coloring, taste or odor
4. Disinfection – chemicals such as chlorine, ozone or UV light is used to disinfect water

24. Treating used water Process:
1.Preliminary treatment – water enters the facility and the larger waste is screened out
2. Primary clarification – other sediment is settled out and used for compost. The water, now called primary effluent, moves to the next step.

25. Settling tank

26. Oxygen tank

27. 3. Flow equalization – storage units that can hold up to 5 million gallons
4. Biological Nutrient removal – the use of microorganisms to remove excess amounts of nitrogen
5. Secondary clarification – here, any remaining solids are settled out. By now, 90% of contaminants have been removed
6. Filtration – water is allowed to trickle though charcoal and sand to remove remaining particles. 99% of contaminants have been removed

28. 7. Disinfection – chlorine is added to kill any remaining bacteria or viruses. Also balanced for pH
8. Distribution – water is either stored or returned to the environment

29. Yummy!!!!!!