
McEachern High School
Engineering & Technology

City Water Supply
WATER TREATMENT
Coagulation and Flocculation
Coagulation and flocculation are often the first steps in water treatment. Chemicals with a positive charge are added to the water. The positive charge of these chemicals neutralizes the negative charge of dirt and other dissolved particles in the water. When this occurs, the particles bind with the chemicals and form larger particles, called floc.
Sedimentation
During sedimentation, floc settles to the bottom of the water supply, due to its weight. This settling process is called sedimentation.
Filtration
Once the floc has settled to the bottom of the water supply, the clear water on top will pass through filters of varying compositions (sand, gravel, and charcoal) and pore sizes, in order to remove dissolved particles, such as dust, parasites, bacteria, viruses, and chemicals.
Disinfection
After the water has been filtered, a disinfectant (for example, chlorine, chloramine) may be added in order to kill any remaining parasites, bacteria, and viruses, and to protect the water from germs when it is piped to homes and businesses.

WATER QUICK FACTS - Source- Environmental Protection Agency
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The average American uses 333 liters (88 gallons) of water per day. Astronauts on the ISS use only 3.78 liters or (1 gallon)
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A full bathtub can require up to 250 liters while taking a 5-minute shower uses less than 50% of that
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Turning off the tap while you brush your teeth can save 30 liters per day.
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A drip rate of one drip per second can waste more than 12 000 liters per year.
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