Water Heroes Program

Lesson 3: Engineering Solutions for Water Filtration

Supplies Needed for this Lesson

1. Water Heroes: Water Filtration Kit�
2. Water Heroes: How To Filter Contaminated Water�
3. Water Purification Packets (Found inside the Water Quality Testing Kits – These are for students to keep)

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Water Contamination

• Point Source Pollution
• Nonpoint Source Pollution

Water can be contaminated by a variety of pathogens to include bacteria, viruses, parasites, and fungi. Some of these pathogens can cause serious illness.

The Contamination You Can’t See

Citizen �Science

• Don’t forget to upload your data (pH and coliform bacteria).
• Your provided data helps us to better understand water quality in the USVI.

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In 2019, the VI DOH and CDC tested the water quality of 400 random USVI cisterns.

80% tested positive for E.coli when the water was taken directly from the cistern.

54% tested positive when the water was taken directly from the tap.

Rainwater is collected in the rain gutters found on the roofs of homes. That water is collected and stored inside of a cistern where it can provide water throughout the house.

Water Filtration: Flint Michigan

Filters are either comprised of a sponge-like membrane or materials such as gravel, sand, and or activated charcoal that can trap and hold on to particles found in water.

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Fibrous material �(like cheesecloth �or cotton balls)

Removes suspended matter

Activated charcoal

Removes chlorine and organic compounds

Sand and gravel Removes suspended matter

How Does A Water Filter Work

Activated Charcoal �Demonstration

Supplies Needed

• Plastic container
• Water
• Blue food coloring
• Coffee filter
• Activated charcoal

Instructions

¹Place a coffee filter inside the plastic bottle. ²Fill the coffee filter with some activated charcoal. ³Pour water dyed with blue food coloring through the water bottle. ⁴Observe.

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Water Treatment

After filtering your water, additional steps may be required to ensure that the water is safe for drinking purposes.

Sand�Small sized gravel �Large sized gravel�Activated charcoal�Potting soil�

Coffee filters

Cotton balls

Cheesecloth

Filter papers

5x

Paper filters

Miscellaneous

Toothpicks

3x Plastic cups

Make sure you have all the supplies.

1. Locate the cup with 5 pre-drilled holes; this will be where you add your filter components.
2. First plug the hole at the bottom with a piece of paper-based filter.
3. Layer the filter components (Sand / Gravel / Paper filters) to your preference. (Use sparingly). The order you stack them will affect output.
4. Insert toothpicks into the pre-drilled holes and stack on top of the other cup.

Let’s Start Filtering Some Water!

• Use the remaining empty cup to make a slurry of dirty water.
• Once your filter is constructed, carefully pour the dirty water at the top of the filter.
• You will want to stack layers from coarse to fine.

Activity

Build your water filters to see who can make the cleanest water.�(Activity sheet #2)

Let’s Recap

• Water is naturally filtered within our watersheds.
• Sand, gravel, and activated charcoal act as natural water filters.
• Filtered water may still not be safe for drinking; disinfection may be required to eliminate traces of harmful pathogens that could lead to illness.
• Time and money often dictate which approach(es) are used to filter contaminated water.

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Water Heroes Program

Lesson 3: Engineering Solutions for Water Filtration

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Hand in your Activity Sheet #2 and tidy up your area.