Warm-Up

1. How do you think clean drinking water gets to your cup? (Write down your best guess)

How does clean water get to your cup?

https://www.youtube.com/watch?v=tuYB8nMFxQA

Flush to Finish: Write these video questions down

1. Is there a difference between where toilet and sink water goes?

2. Is storm water just storm water?

3. Why should you not flush things down the toilet?

4. What do wastewater treatment plants do?

5. At treatment plants, more than ____ % of pollutants are removed.

6. Does drinking water come from the same place wastewater goes?

7. What’s allowed down in the toilet?

Wastewater treatment video

http://www.youtube.com/watch?v=oaXth88i7rk

Flush to Finish: Check your answers

1. It all drains to the same place

2. No, because of fertilizers and car cleaning products

3. Because items clog pipes and drains

4. Make water cleaner than when it arrived.

5. At treatment plants, more than 90 % of pollutants are removed.

6. Yes, drinking water comes from what was wastewater

7. #1, #2, and TP (toilet paper), and soap and water

Water pollution is anything that changes the quality conditions of

water . That’s why we treat sewage/ wastewater, so that it doesn’t diminish (lower) water quality.

5 Steps of Treating Wastewater

1st: Preliminary Treatment • Wastewater arrives at the

treatment plant and goes through bar screens that take out large debris (like diapers, leaves, and trash)

Preliminary Treatment

Preliminary Treatment Continued

Finally, solids are allowed to settle out of the water and the scum to rise. The system then collects the solids for disposal (either in a landfill or an incinerator).

2nd: 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

3rd: 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

4th -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

Chlorination Tank

5th 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 clarifier

Finally: What do we get from treating water

• Biosolids, the nutrient-rich organic matter produced by treating wastewater solids, can be used as a fertilizer or a bio-fuel

• Reclaimed Water – goes back into the water supply (like a lake or river) This water is not clean enough to drink yet, there is another treatment process to make it potable!

• Energy recovery –biofuels/ biomatter, is a byproduct of the bio-solids, it is collected and used on-site in generators that produce electricity and for powering pumps.

Change of topic: How do we make water clean enough to

drink?

Where does drinking water come from?

• How is treating water (to make it drinking water) similar to treating waste water?

• How is treating water (to make it drinking water) different than treating waste water?

Where does drinking water come from?

http://www.youtube.com/watch?v=eIoSt0-K7wI

Steps for purifying drinking water 1. Water is taken in by a treatment plant

Steps for purifying drinking water Step 2: water passes through a carbon filter (to get

harmful substances like chemicals)

Step 3: Water passes through a paper filter (to get sediment like dirt)

Steps for purifying drinking water Last steps:

- Water goes through reverse osmosis to remove impurities

- It’s disinfected with UV light

- Finally, the water is electrocuted (like lightning) to finish cleaning the water and killing germs

What can we do if we need water and the only water available is salty ocean

water?

Want to drink salty water? 1. In 20 years _________ % of the world’s

population will live in areas with serious water ________ (shortages)

2. What percent of people live near the coast?

3. The pressure put on the water to remove salt is equal to what?

4. This process is called what?

5. In 2015, what percent of drinking water will have been desalinated?

Want to drink salty water?

https://www.youtube.com/watch?v=aysj7696b0A

Want to drink salty water? 1. In 20 years 47% of the world’s population

will live in areas with serious water scarcity (shortages)

2. 40% of people live near the coast

3. The pressure is equal to 100 elephants standing on a man-hole cover

4. This process is called reverse osmosis

5. 2% will have been desalinated

• Desalination: Removing salt from water (usually ocean water)

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

Look what desalination can do

Next Steps: 1. Read Desalination article and answer questions 2. Create a comic or a short story that shows how

water goes from being used in the toilet to being in a cup or bottle of water (should include all the steps from sewage water treatment to drinking water treatment)

3. Exit Ticket:

– Is treated water clean enough to drink?

– Is bottled water better than tap water? Why or why not?