Water and Global Responsibility STEM Unit
LP7_Water Treatment
Lesson Plan 7: Water Treatment
Overview
In this lesson students learn how to keep their water safe through the multi-barrier
approach. They identify the steps by reflecting on what they know about municipal water
treatment and then look at how these steps can be replicated at a household level.
Background Knowledge:
Prior to this lesson students should visit their local water treatment plant and/or have an
understanding of how their own drinking water is treated before it reaches the tap.
Students should also participate in Tikho’s Story Parts 1 and 2 and have a basic
understanding of the following concepts:
 What is safe water
 How our water is contaminated
 What happens when people drink unsafe water
Educators may want to read about the multi-barrier approach prior to conducting the
lesson.
Time Required: 2 hours
Grade Level: Grades 5 and 6
Subject Area: Science, Language Arts, Social Studies, Art
Key Words: Source Water Protection, Sedimentation, Filtration, Disinfection, Safe
Storage
Alberta Curriculum Links: See curriculum link table
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Water and Global Responsibility STEM Unit
LP7_Water Treatment
Lesson Plan 7: Water Treatment
1 hr
Learning Expectations
1. Explain the five barriers of the multi-barrier approach and how they work to
make water safe to drink.
2. Identify examples of the multi-barrier approach in the municipal water system.
3. Discuss examples of how the multi-barrier approach can be applied at a
household level.
Materials
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Multi-barrier approach pictures (see end of lesson plan for pictures)
Optional: LCD Projector to project pictures
Preparation
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Read about the multi-barrier approach on CAWST’s Wavemakers website.
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Print and laminate pictures of multi-barrier approach (see below) or prepare
LCD projector to project them.
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Create a clear space in your room or find a space outside where student can
run around safely without knocking into things.
Introduction
10 minutes
Note: this activity should be done in an open space where students can run
around safely, without knocking into things.
You will need 16 volunteer students for this exercise: 1 = human; 10 =
barriers (2 people with linked arms per barrier); 5 = pathogens)
1. Ask for a volunteer and tell them to come to the front of the class.
2. Explain that the volunteer represents a human that needs to be protected
from the pathogens/germs in water.
3. Ask for 5 more students to volunteer. Tell them that they represent the
pathogens in water. If they succeed in touching the human, the human will
get sick.
4. Tell the “human” to stand still. Ask the 5 pathogens to try and touch the
human.
5. Ask the pathogens if it was easy or difficult to touch the human. (Easy). Ask
the rest of the class what could be done to protect the human. (Get people to
protect him/her.)
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LP7_Water Treatment
6. Ask for two students to come up to the front of the class and link arms.
Explain that they represent a barrier. Their job is to protect the human. They
are allowed to move around but should stay linked in some way.
7. Let the pathogens “attack” and then ask them how it felt compared to last
time. (They will still be able to touch the human but it should be slightly harder
than before.)
8. Continue to add barriers one at a time until you reach five. Before new
barriers are added, ask the “pathogens” to reflect on how easy or difficult it
was to touch the human. By the last barrier it should be very difficult/not
possible for them to touch the human.
9. Ask the participants who were observing what they noticed about the game.
Each time a barrier was added it was more difficult for the pathogens to get to
the humans.
Introduction to the Multi-barrier Approach
30 minutes
1. Ask students what the barriers represented. The processes used to make
water safe to drink or keep people from drinking unsafe water.
2. Ask students how many barriers there were in the game (5). Write the
numbers 1 to 5 on the board.
3. Ask them to think back to their trip to the municipal water treatment plant or
what they have learned about how water is treated. Ask them to explain some
of the barriers or treatment processes.
4. As they come up with barriers/treatment process, write them beside the
appropriate number until you have a list on the board that looks like the one
below with examples:
i.
Source water protection
ii.
Sedimentation
iii.
Filtration
iv.
Disinfection
v.
Safe Storage
Household water Treatment
20 minutes
1. Explain that there are communities, like Tikho’s where water isn’t treated by
the municipality.
2. There are things these communities can do at a household level to protect
their water source.
3. Show students the multi-barrier approach pictures (see pages 6-10 of this
document). Ask them to explain each picture.
4. Ask students to match the pictures with each of the steps of the multi-barrier
approach. Write the steps on the board and ask them to stick the pictures
beside the corresponding step.
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Water and Global Responsibility STEM Unit
LP7_Water Treatment
I. Source water protection (covering a well, putting a fence around a
spring)
II. Sedimentation (letting water sit until the fines separate)
III. Filtration (Biosand filter)
IV. Disinfection (chlorine, boiling)
V. Safe Storage (putting safe water in a clean container with a lid)
Review
30 min
1. Ask students to discuss the following questions with a partner:

What are the 5 steps to the multi-barrier approach?

What is an example of these steps at a municipal level?

What is an example of these steps at a household level?
Resources
Multibarrier approach pictures can be found below.
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