Water Treatment 012-10992 r1.04

Water Treatment 012-10758 r1.04

The Snapshot button is used to capture the screen.

The Journal is where snapshots are stored and viewed.

The Share button is used to export or print your journal to turn in your work.

IntroductionJournals and Snapshots

Note: You may want to take asnapshot of the first page ofthis lab as a cover page for your journal.

Each page of this lab that contains the symbol

should be inserted into your journal. After completing a lab page with the snapshot symbol, tap (in the upper right hand corner) to insert the page into your journal.

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Lab Challenge• What are some of the processes used to treat water and make it safe to

drink? What contaminants are removed by water treatment methods?

• How would you design an effective water treatment system?

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Background• There are several steps in the water treatment process. A primary step is

filtration.

• Filtration technology is very effective and can remove nearly any impurities from water but it is not very cost-effective (replacement filters are costly).

• So most water treatment systems use filtration in combination with other simpler methods like coagulation, flocculation, and chemical disinfection.

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Self-check1. Why don't municipal water treatment plants

simply use giant filters to clean water, similar to the portable filters used by hikers?

a) Filters are not effective at cleaning water.

b) Replacing large filters is too expensive.

c) Giant filters are too heavy to carry while hiking.

d) Filter technology is not reliable.

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...Background• Both types of water treatment—for wastewater or

sink/shower water—start by passing the water through a gridded screen to catch larger objects.

• Then a coagulant is added to the water. Salts of aluminum (alum) or water-soluble organic polyelectrolytes are often used as coagulants. Coagulants cause suspended particles to form clumps.

• These clumps aggregate into larger clumps, or flocs, during the flocculation process. The flocs are dense enough to settle out of the water in a process called sedimentation.

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Self-check2. What is the purpose of a coagulant?

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...Background• The water is then filtered through a variety of media

of varying porosities, including activated carbon, sand, and gravel. Filtration works by trapping impure particles in the filtration media as the water slips through the cracks.

• At this point the water looks clean but is still not quite ready. Several final disinfecting precautions must be taken to eliminate viral or bacterial sources that can cause disease. Three common ways to disinfect are treatment with chlorine, bubbling ozone through the water, or shining ultraviolet light through the water.

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...BackgroundWater Treatment

Water from source

Drinking water to homes

Coagulant addition

Mixing/flocculation basin

Sedimentation basin

Sludge to disposal

Filtration tanks

ChlorinationStorage reservoir

Self-check3. Why is it necessary to further treat water once it has been through the

filtering process?

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Safety• Follow all standard laboratory safety procedures.

• Wear safety glasses.

• Keep water away from sensitive electronic equipment.

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Materials and EquipmentCollect all of these materials before beginning the lab.• Water quality sensor (or separate

pH and conductivity sensors)• Turbidity sensor (optional)• Beaker, 150-mL (4)• Beaker, 50-mL (1)• Large beaker for containing waste• Large test tube, 18-mm or more• Pipette and bulb• 500-mL soda bottle• Stirring rod

• Activated charcoal (2 g)• Swimming pool water clarifier solution,

4% (2-mL)• "Wastewater" sample (500-mL)• Tap water• Wash bottle containing deionized water• Paper towels, kitchen, white, roll

(several)• Lint-free lab tissue• Paper napkins, white, smooth (12)

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The steps to the left are PART A of the procedure for this lab activity. They are not in the right order. Write the correct sequence below, then take a snapshot of this page.

A. Connect the pH, conductivity, and turbidity sensors. Calibrate the turbidity sensor.

B. Observe the odor and measure the pH, conductivity, and turbidity of the "wastewater" water sample.

C. Make a paper filter and use it to filter the "wastewater" water sample. Make observations and measurements as before.

D. Pre set-up sedimentation, agglutination, and "wastewater" samples. Set aside for at least 30 minutes. Set up your activated charcoal.

Sequencing Challenge: Part 1Water Treatment

A. Collect an aliquot of the "wastewater" sample. Observe its odor and measure the pH, conductivity, and turbidity.

B. Make a paper filter; filter the agglutinated water sample. Make observations and measurements as before.

C. Use an activated charcoal-coated filter on the "wastewater" water. Observe odor, color, pH, conductivity, and turbidity.

D. Test the pH/conductivity of the charcoal-filtered water.

E. Test your design and evaluate the results.

F. Design a water treatment technique using the technologies you studied in this lab that you think will best treat the wastewater.

Sequencing Challenge: Part 2Water Treatment

The steps to the left are PART B of the procedure for this lab activity. They are not in the right order. Write the correct sequence below, then take a snapshot of this page.

Setup1. Stir the "wastewater" sample to uniformly mix it.

2. Pour 100 mL of the well-mixed "wastewater" sample into each of four 150-mL beakers. Label the beakers as follows:

Beaker 1 = “Untreated”

Beaker 2 = “Activated Charcoal”

Beaker 3 = “Sedimentation”

Beaker 4 = “Coagulation” (agglutination)

3. Set Beaker 3 (sedimentation) aside for at least 30 minutes.

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4. To set up the agglutination sample, put 2 mL of the 4% swimming pool clarifier solution into Beaker #4 and stir vigorously. Note: Swimming pool clarifier contains coagulating agents that are similar to those used in municipal water treatment facilities.

5. Record any changes in appearance below. Periodically stir this solution over the next 30 minutes.

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Setup

Setup6. Create a membrane filter. Start by cutting off the

bottom half of a plastic 500-mL soda bottle. Turn the top half over as a simple funnel.

7. Fold a paper towel in half, and then fold it in half again. Separate the layers to make a funnel.

8. Stack 3 paper napkins together, and shape them into a shallow bowl. Tuck these into the paper funnel, and push the entire membrane construction into the funnel, forming a bowl to hold the filtrant. Set this aside for now.

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Setup 9. Connect a water quality sensor (or pH and conductivity sensors) to your

data collection system.

Note: It is not necessary to calibrate the conductivity sensor for this activity.

10. Calibrate the pH sensor (see instructions in blue on next page).

11. Using an extension cable, connect and calibrate the turbidity sensor using the two calibration samples provided with your sensor. For each test, you will be taking an aliquot (small sample) with the clean sample bottles provided with your turbidity sensor.

Note: The use of the turbidity sensor in this lab is optional. If you are not using a turbidity sensor, skip procedures that use this sensor.

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Note: Only calibrate the sensor if instructed to do so by your teacher.

To Calibrate the pH Sensor:

Note: During the calibration process you will not be able to return to this page.

1. Open the Calibrate Sensor screens: a. Tap b. Tap CALIBRATE SENSOR

2. Ensure that the correct measurements are selected: a. Sensor: (name of sensor) Measurement: pH Calibration Type: 2 point b. Tap NEXT

3. Calibration Point 1: a. Place the pH probe in a pH 4 buffer solution. b. Enter 4.0 as the pH in the Standard Value box

under Calibration Point 1. c. Tap Read From Sensor under Calibration Point

1. d. Rinse the pH probe thoroughly using distilled

water.

4. Calibration Point 2:a. Repeat the process used in calibration point 1

using a pH 10 buffer solution. b. Tap OK to exit the calibration screen and then

tap OK again to return to the lab.

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PredictQ1: Which water treatment method is most likely to remove odors, colors,

particles, etc? Make predictions in the space below. Possible methods include Metal Gratings, Coagulation, Flocculation, Sedimentation, Filtration, and Disinfection.

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Procedure 1. Examine the untreated “wastewater” in Beaker #1. After you begin to collect

data, you will be able to record your observations in a data table that will expand as you examine all your samples.

2. Make a note of the odor, color and appearance of the wastewater in Beaker #1. You will record this in the table on pg. 23.

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8. Then take an aliquot of the untreated water and measure with the turbidity sensor.

9. Record the result in the data table on next page.

6. Next measure the untreated water with the conductivity sensor.

7. Record the result in the data table on next page.

3. Measure the untreated water with the pH sensor.

4. Tap to activate the sensor and to deactivate.

5. Record the result in the data table on next page.

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*To Enter Data into a Table: 1. Tap to open the tool

palette.2. Tap then tap a cell in

the data table to highlight it in yellow.

3. Tap to open the Keyboard screen.

10.Now filter this untreated wastewater by pouring half of it into the paper filter. Collect the filtered wastewater (filtrate) in a 50-mL beaker. Be careful to keep the liquid contained inside the paper napkin "bowl". Don't let it overflow!

11. Record the odor an color/appearance of the filtered water in the adjacent data table.

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12. Transfer the filtered water (filtrate) to a large test tube.

13. Measure the filtrate with the pH sensor.

14. Record the result in the data table on the next page.

15. Next measure the filtrate with the conductivity sensor.

16. Record the result on the next page.

17. Finally, take an aliquot and measure the filtrate with the turbidity sensor.

18. Record the result on the next page.

19. Rinse all beakers and test tubes.

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Procedure: Membrane FiltrationDid your simple filter turn the "wastewater" into clear drinking water? Probably not! So let's look at some additional water treatment methods on the next page.

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Procedure: Membrane Filtration + Activated Charcoal1. Create a membrane filter with activated charcoal. Reuse the plastic bottle

funnel. Fold a paper towel in half, and then fold it in half again. Separate the layers to make a funnel. Stack 3 paper napkins into a shallow bowl and tuck these into the paper funnel. Push the entire membrane construction into the funnel, forming a bowl to hold the filtrant.

2. Add 1 gram of activated charcoal to 100 mL of tap water and stir. Put this slurry into the filter.

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Procedure: Membrane Filtration + Activated Charcoal3. Slowly pour an additional 100 mL of tap water into the filter. You should now

have a membrane filter covered with a layer of activated charcoal. If the tap water filtering through it is not clear, filter an additional 100 mL of tap water.

Note: This step ensures that the activated carbon becomes fixed inside the filter and is not leaking out into the filtrate.

Note: Activated charcoal is prepared so that it is extremely porous and can thus trap and remove molecules, especially large organic molecules such as those responsible for odors and colors. The activated charcoal must then be filtered out of the sample.

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4. Pour about 80 mL of the "wastewater" from Beaker #2 into the charcoal filter.

5. As the water filters through, discard the first 30 mL or so. Collect the remaining filtrate in a clean 50 mL beaker.

6. Examine the resulting filtrate. Record its odor, color and appearance in the adjacent data table.

7. Transfer the filtrate to a large test tube for further sensor testing.

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13. Finally, measure the filtrate with the turbidity sensor.

14. Record result in the data table on next page.

15. Rinse beakers and test tube.

11. Next measure the filtrate with the conductivity sensor.

12. Record the result in the data table on next page.

8. Measure the filtrate in the large test tube with the pH sensor.

9. Tap to activate the sensor and to deactivate.

10. Record result in data table on next page.

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Procedure: Coagulation + Filter1. Examine the coagulated sample in Beaker #4.

2. Note any major differences in appearance between the untreated wastewater (Beaker #1) and the coagulated wastewater (Beaker #4). Record your observations below.

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Procedure: Coagulation + Filter3. Create another membrane filter (without activated charcoal).

4. Reuse the plastic bottle funnel. Fold a paper towel in half, and then fold it in half again. Separate the layers to make a funnel. Stack 3 paper napkins into a shallow bowl and tuck these into the paper funnel. Push the entire membrane construction into the funnel forming a bowl.

5. Place the coagulated wastewater in Beaker #4 into the filter. Catch the filtrate drippings in a clean beaker.

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6. Examine the coagulation filtrate. Record the odor, color and appearance in the adjacent data table. Transfer the filtrate to the large test tube.

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10. Next measure the coagulation filtrate with the conductivity sensor.

11. Record the result in the data table on next page.

7. Measure the coagulation filtrate with the pH sensor.

8. Tap to activate sensor and to deactivate.

9. Record the result in the data table on next page.

12. Then measure the coagulation filtrate with the turbidity sensor.

13. Record result in data table on next page.

14. Rinse beakers and test tube.

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Procedure: Sedimentation1. Carefully pipette a 30 mL sample from the top of the solution in

Beaker #3 (sedimentation sample), being careful not to disturb the solution.

2. Place the sedimentation sample in the test tube for analysis.

Note: You will not filter this sample. Instead we will examine how effective the process of sedimentation can be in cleaning water.

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3. Examine the sedimentation sample in the test tube. Record its odor, color and appearance in the adjacent data table.

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Note: After you post the data for this sample, take a picture of your completed table on pg. 41 for your journal.

4. Measure the sedimentation sample with the pH sensor.

5. Tap to activate sensor and to deactivate.

6. Record the result in the data table on next page.

7. Next measure the sedimentation sample with the conductivity sensor.

8. Record the result in the data table on next page.

9. Measure sedimentation sample with the turbidity sensor.

10. Record the result in the data table on next page.

11. Clean all equipment per teacher's instructions.

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Analysis1. Compare your earlier predictions with your data table results.

Which result surprised you the most? Please explain.

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Analysis2. What were the effects of filtering the "wastewater" using a

plain membrane filter?

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Analysis3. What were the effects of filtering the "wastewater" using an

activated-charcoal filter?

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Analysis4. What was the effect of treatment with an coagulating/agglutinating agent?

What was the effect of coagulation + membrane filtration?

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Analysis5. What was the effect of treatment with sedimentation? How might this

treatment be improved?

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Analysis6. What quality of water is measured with the conductivity sensor?

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Analysis7. Which treatment method worked best for eliminating odors?

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Analysis8. Which treatment method worked best for changing the color of the water

(removing the cloudiness)? Which was least effective?

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Analysis9. What was the effect of treatment on pH?

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Analysis10. What was the effect of treatment on conductivity (dissolved salt) levels?

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Synthesis1. What are some differences between the treatment of water to be used

for human consumption compared with treatment of wastewater to be discharged into the environment?

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Synthesis2. Suppose you had to design a water treatment system that could

reliably produce large volumes of water clean enough for safe human consumption.

What treatment methods would you include? Why?

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Multiple Choice1. The main purpose of sewage treatment is to

__________.

a) kill pathogenic bacteria and to reduce odor

b) remove biodegradable materials from the water and kill pathogenic bacteria

c) kill pathogenic bacteria and remove plant nutrients

d) kill pathogenic bacteria, remove biodegradable materials, and make the water safe for human use

e) None of the above.

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2. The main purpose of drinking water treatment is to __________.

a) kill pathogenic bacteria and to reduce odor

b) remove biodegradable materials from the water and to kill pathogenic bacteria

c) kill pathogenic bacteria and remove plant nutrients

d) kill pathogenic bacteria, remove biodegradable materials, and make the water safe for human use

e) None of the above.

Multiple ChoiceWater Treatment

Modern water treatment plant

What happens when water treatment fails!

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You have completed the lab.Congratulations!

Please remember to follow your teacher's instructions for cleaning-up and submitting your lab.

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All images were taken from PASCO documentation, public domain clip art, or Wikimedia Foundation Commons:

http://commons.wikimedia.org/wiki/File:STSTW_Effluent.jpghttp://commons.wikimedia.org/wiki/File:Glass-of-water.jpg http://commons.wikimedia.org/wiki/File:Canal-pollution.jpg http://commons.wikimedia.org/wiki/File:Pfeil_rechts.svg.jpg http://commons.wikimedia.org/wiki/File:Fluor_Fernald_Workers.jpghttp://commons.wikimedia.org/wiki/File:Rwenzori_mineral_water.jpghttp://commons.wikimedia.org/wiki/File:Glass_of_Water.JPG http://www.freeclipartnow.com/office/paper-shredder.jpg.html

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