Water Chapter 20

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WaterChapter 20

• There is the same amount of water on Earth as
  there was when the Earth was formed. The water
  from your faucet could contain molecules that
  dinosaurs drank!

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What we will cover ?

• Discussion of Lab
• Uses for Water (20.1)
• Water Resources (20.2)
• Water Treatment (20.3)

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Lab Discussion

• What did you learn?
• Why do you think we test pH?
• City water is adjusted to pH 7
• Why is chlorine added to drinking water?
• To kill bacteria, germs, and control algae
• What is hard water?
• Contains a lot of calcium and magnesium
• How would we know we have hard water without
  testing it?

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Definitions

• Potable water
• Unpotable water

Safe for drinking
Not safe for drinking
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20.1 Uses for Water

• Residential Use
• Personal hygiene and home cleaning
• Clothes washing 140-170L
• Showering 75-80L
• Machine dishwashing 56-60L
• Shaving 39-58L
• Brushing teeth 19-39L
• Toilet flushing 16-21L per flush
• Washing hands and face 4-8L

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Uses for Water

• Residential Uses
• Personal hygiene and home cleaning
• Drinking and Cooking
• Outside the home
• Watering the lawn
• Gardening
• Car washing
• Recreational activities (i.e. swimming pool)

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Uses for Water

• Industrial Use
• Transport goods
• Dispose of Wastes
• Power source
• Coolant
• Agricultural Use
• Irrigation bringing water to an area for the use
  of growing crops
• Flood
• Furrow
• Overhead
• Subirrigation

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2)
1)
3)

• Furrow Irrigation
• Flood Irrigation
• Overhead Irrigation

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Effects of Water Use on Ecosystems

• Building dams
• Draining swamps
• Removal of water from natural sources
• Effect food chains, forcing those that feed on
  organisms that live in water to migrate (such as
  birds)

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Time to Fill in your Worksheet!!

• Define potable water
• water safe for drinking
• Define unpotable water
• water not safe for drinking
• Define irrigation
• the process of bringing water to an area for use
  in growing crops

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Time to Fill in your Worksheet!!

• Three main categories in which water is used
• Residential
• Name two ways
• Industrial
• Name two ways
• Agricultural
• Name two ways
• Name three ways human water use effects
  ecosystems
• Dams, draining swamps, removal of water from
  natural sources

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20.2 Water Resources

• Natural storage of water as a resource
• Surface water
• Streams, lakes, ponds
• Ground water
• Aquifers

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AQUIFERS
Water Table top layer of the zone of saturation
where groundwater collects and saturates the
bedrock, (where you withdraw your well water)
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Water Resources Problems

• Overdraft
• When a body of water is drained faster than it is
  filled

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Two problems associated with overdraft

• Saltwater intrusion
• Subsidence

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Time to Fill in your Worksheet!!

• What is surface water?
• Water aboveground in streams, lakes, and ponds
• What is ground water?
• Water within porous or jointed bedrock, stored in
  aquifers
• Define water table.
• The top of the zone of saturation where
  groundwater collects and saturates the bedrock
• What causes overdraft?
• Removal of water from a body of water faster than
  the body of water is filled

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20.3 Water TreatmentNow fill in as we go

• Did you know??
• Nearly 97 of the worlds water is salty or
  otherwise undrinkable. Another 2 is locked in
  ice caps and glaciers. That leaves only for
  all of humanitys needsall its agricultural,
  residential, manufacturing, community, and
  personal needs.

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20.3 Water Treatment

• Why is fresh water in many parts of the world not
  potable??
• Ex South America, Mexico, China, and parts of
  Africa
• When visiting these countries, should you pour
  your bottled water (clean water) over ice? Why or
  Why not??
• What is limited by access to fresh water?

Bacterial and chemical contamination, not
sufficient technology available to purify the
water
No! Ice is made from the unpotable water!!
Population Growth
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(1)
(2)
(3)
(4)
(5)
(6)
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(1) Find source of water and withdrawal amount
for treatment (usually a constant withdrawal for
municipalities)
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(2) Sedimentation Large matter falls out
(leaves, sticks, big dirt particles)
Coagulation Chemical additives (coagulants)
added to cause fine particles to clump together
and settle out
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(3) Filters Vary by treatment plant, but at
least 1m thick layer of sand to trap what didnt
fall out during sedimentation and coagulation
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(4) Aeration exposure of water to air and
sunlight to add oxygen as a purifying
agentSterilization Ozone is a strong
sterilizer, but often chlorine is used because it
is less expensive
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(5) Storage Reservoirs Several types, and
generally located at the highest point of the
distribution plane
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(6) Distribution to consumers
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Alternatives

• Salt water?
• YES! Desalination (removing of the
  salt)expensive, but some states are resorting to
  this!
• Wells
• Cisterns

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Time to Fill in your Worksheet!!

• What are the six main steps in water
  purification/water treatment?
• Locate and withdrawal from source
• Sedimentation and coagulation
• Filtration
• Aeration and Sterilization
• Storage
• Distribution to consumers

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Time to Fill in your Worksheet!!
Label your water treatment diagram on the back of
your worksheet
2) Sedimentation Coagulation
3)
Filtration
1) Locate withdrawal from source
4)
5) Storage
Aeration Sterilization
6) Distribution