Water Treatment
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Water Treatment
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Water Treatment
Introduction
Journals and Snapshots
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.
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.
Note: You may want to take a
snapshot of the first page of
this lab as a cover page for
your journal.
Water Treatment
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?
Water Treatment
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.
Water Treatment
Self-check
1. 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.
Water Treatment
...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.
Water Treatment
Self-check
2. What is the purpose of a coagulant?
Water Treatment
...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.
Water Treatment
...Background
Water
from
source
Drinking
water to
homes
Filtration
tanks
Coagulant
addition
Mixing/floccula
tion basin
Sedimentati
on basin
Sludge to
disposal
Storage
reservoir
Chlorination
Water Treatment
Self-check
3. Why is it necessary to further treat water once it has been through the
filtering process?
Water Treatment
Safety
• Follow all standard laboratory safety procedures.
• Wear safety glasses.
• Keep water away from sensitive electronic equipment.
Water Treatment
Materials and Equipment
Collect all of these materials before beginning the lab.
• Water quality sensor (or separate
• Activated charcoal (2 g)
pH and conductivity sensors)
• Swimming pool water clarifier solution,
• Turbidity sensor (optional)
4% (2-mL)
• Beaker, 150-mL (4)
• "Wastewater" sample (500-mL)
• Beaker, 50-mL (1)
• Tap water
• Large beaker for containing waste
• Wash bottle containing deionized water
• Large test tube, 18-mm or more
• Paper towels, kitchen, white, roll
(several)
• Pipette and bulb
• Lint-free lab tissue
• 500-mL soda bottle
• Paper napkins, white, smooth (12)
• Stirring rod
Water Treatment
Sequencing Challenge: Part 1
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.
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.
Water Treatment
Sequencing Challenge: Part 2
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.
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.
Water Treatment
Setup
1. 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.
Water Treatment
Setup
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.
Water Treatment
Setup
6. 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.
Water Treatment
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.
Water Treatment
To Calibrate the pH Sensor:
Note: Only calibrate the sensor if
3. Calibration Point 1:
instructed to do so by your teacher.
a. Place the pH probe in a pH 4 buffer solution.
Note: During the calibration process you
b. Enter 4.0 as the pH in the Standard Value box
will not be able to return to this page.
under Calibration Point 1.
c. Tap Read From Sensor under Calibration Point
1. Open the Calibrate Sensor screens:
1.
a. Tap
d. Rinse the pH probe thoroughly using distilled
b. Tap CALIBRATE SENSOR
water.
2. Ensure that the correct
measurements are selected:
a. Sensor: (name of sensor)
Measurement: pH
Calibration Type: 2 point
b. Tap NEXT
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.
Water Treatment
Predict
Q1: 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.
Water Treatment
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.
Water Treatment
3. Measure the untreated
water with the pH sensor.
6. Next measure the untreated
water with the conductivity
sensor.
8. Then take an aliquot of the
untreated water and
measure with the turbidity
sensor.
4. Tap
to activate the
sensor and
to deactivate. 7. Record the result in the data
table on next page.
9. Record the result in the data
5. Record the result in the data
table on next page.
table on next page.
Water Treatment
*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.
Water Treatment
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.
Water Treatment
12. Transfer the filtered water 15. Next measure the filtrate
(filtrate) to a large test
with the conductivity
tube.
sensor.
13. Measure the filtrate with 16. Record the result on the
the pH sensor.
next page.
14. Record the result in the
data table 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.
Water Treatment
Water Treatment
Procedure: Membrane Filtration
Did 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.
Water Treatment
Procedure: Membrane Filtration + Activated Charcoal
1. 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.
Water Treatment
Procedure: Membrane Filtration + Activated Charcoal
3. 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.
Water Treatment
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.
Water Treatment
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.
11. Next measure the
filtrate with the
conductivity sensor.
12. Record the result in the
data table on next
page.
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.
Water Treatment
Water Treatment
Procedure: Coagulation + Filter
1. 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.
Water Treatment
Procedure: Coagulation + Filter
3. 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.
Water Treatment
6. Examine the coagulation
filtrate. Record the odor,
color and appearance in
the adjacent data table.
Transfer the filtrate to the
large test tube.
Water Treatment
7. Measure the coagulation
filtrate with the pH sensor.
8. Tap
and
to activate sensor
to deactivate.
9. Record the result in the
data table on next page.
10. Next measure the
coagulation filtrate with
the conductivity sensor.
12. Then measure the
coagulation filtrate with
the turbidity sensor.
11. Record the result in the
data table on next
page.
13. Record result in data table
on next page.
14. Rinse beakers and test
tube.
Water Treatment
Water Treatment
Procedure: Sedimentation
1. 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.
Water Treatment
3. Examine the sedimentation
sample in the test tube.
Record its odor, color and
appearance in the adjacent
data table.
Note: After you post the
data for this sample, take
a picture of your
completed table on pg. 41
for your journal.
Water Treatment
9. Measure sedimentation
7. Next measure the
sample with the turbidity
sedimentation sample with
sensor.
the conductivity sensor.
5. Tap
to activate sensor and
10. Record the result in the
to deactivate.
8. Record the result in the
data table on next page.
data
table
on
next
page.
6. Record the result in the data
4. Measure the sedimentation
sample with the pH sensor.
table on next page.
11. Clean all equipment per
teacher's instructions.
Water Treatment
Water Treatment
Analysis
1. Compare your earlier predictions with your data table results.
Which result surprised you the most? Please explain.
Water Treatment
Analysis
2. What were the effects of filtering the "wastewater" using a
plain membrane filter?
Water Treatment
Analysis
3. What were the effects of filtering the "wastewater" using an
activated-charcoal filter?
Water Treatment
Analysis
4. What was the effect of treatment with an coagulating/agglutinating agent?
What was the effect of coagulation + membrane filtration?
Water Treatment
Analysis
5. What was the effect of treatment with sedimentation? How might this
treatment be improved?
Water Treatment
Analysis
6. What quality of water is measured with the conductivity sensor?
Water Treatment
Analysis
7. Which treatment method worked best for eliminating odors?
Water Treatment
Analysis
8. Which treatment method worked best for changing the color of the water
(removing the cloudiness)? Which was least effective?
Water Treatment
Analysis
9. What was the effect of treatment on pH?
Water Treatment
Analysis
10. What was the effect of treatment on conductivity (dissolved salt) levels?
Water Treatment
Synthesis
1. 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?
Water Treatment
Synthesis
2. 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?
Water Treatment
Multiple Choice
1. 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.
Water Treatment
Multiple Choice
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.
Water Treatment
Modern water
treatment plant
What happens when water
treatment fails!
Water Treatment
Congratulations!
You have completed the lab.
Please remember to follow your teacher's instructions for cleaning-up and submitting
your lab.
Water Treatment
References
All images were taken from PASCO documentation, public domain clip art, or Wikimedia Foundation Commons:
http://commons.wikimedia.org/wiki/File:STSTW_Effluent.jpg
http://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.jpg
http://commons.wikimedia.org/wiki/File:Rwenzori_mineral_water.jpg
http://commons.wikimedia.org/wiki/File:Glass_of_Water.JPG
http://www.freeclipartnow.com/office/paper-shredder.jpg.html