1. What happens to water after we’re done with it?
From Flush to Finish
What happens to water after we’re done with it?

2. Average Per Person Daily Water Use in the US (Liters)
Flushing Toilet 90
Bathing 70
Brushing Teeth 10
Cleaning 20
Cooking and Drinking

3. Wastewater
Once water flows down the drain, it is carried through a series of sewage pipes that carry it to a wastewater treatment plant where it is filtered and treated to make the water clean enough to return to a river or lake.

4. Wastewater Treatment Process
Primary Treatment
1. Filtration Wastewater is passed through a large screen to remove solid objects

5. 1. FILTRATION
SOLIDS REMOVED

6. Wastewater Treatment Process
Primary Treatment
1. Filtration Wastewater is passed through a large screen to remove solid objects
2. First Settling Tank: Wastewater is sent into a large tank, where smaller particles sink to the bottom and form sewer sludge. The sludge is removed from the water.

7. 1. FILTRATION
2. 1st Settling Tank

8. Secondary Treatment
3. Aeration Tank: Wastewater is mixed with oxygen and bacteria. The bacteria use the oxygen and feed on the wastes.

9. 1. FILTRATION 2. 1st Settling Tank 3. AERATION TANK
LARGE SOLIDS REMOVED
3. AERATION TANK

10. Secondary Treatment
3. Aeration Tank: Wastewater is mixed with oxygen and bacteria. The bacteria use the oxygen and feed on the wastes. 4. Second Settling Tank: Bacteria grown in the aeration tank, as well as other solid wastes, are removed in the form of sludge.

11. 1. FILTRATION 2. 1st Settling Tank 3. AERATION TANK
4. SECOND SETTLING TANK

12. Secondary Treatment
Aeration Tank: Wastewater is mixed with oxygen and bacteria. The bacteria use the oxygen and feed on the wastes.
4. Second Settling Tank: Bacteria grown in the aeration tank, as well as other solid wastes, are removed in the form of sludge.
5. Chlorination: Chlorine is added to disinfect the water before it is released into a stream, lake or ocean.

13. 1. FILTRATION 2. 1st Settling Tank 3. AERATION TANK 5. CHLORINATION
4. SECOND SETTLING TANK

14. Wastewater Treatment
Most wastewater from homes contains biodegradable material such as plant and animal wastes, paper and soap.
However, wastewater treatment plants may not remove all of the harmful substances in water.
Some household and industrial wastewater and some storm-water runoff contains toxic substances that cannot be removed by the standard treatment, SO…

15. BE CAREFUL WHAT YOU PUT DOWN THE DRAIN