Transcript Chapter 12 - Churchill High School

CHAPTER 12
FRESHWATER RESOURCES
WATER TREATMENT
The EPA sets standards on everything that can
be found in water
 These standards are to make sure that your
drinking water is safe
 Things get into your water through natural and
unnatural ways
 The concentration is the amount of a substance
that is in another substance
 Water is tested regularly to make sure these
standards are meet

THINGS THAT CAN BE IN WATER
Here are some examples of things found in your
drinking water
 Copper

Natural deposits; household pipes
 1.3 ppm
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Cyanide;
Various factories
 0.2 ppm
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Lead
Natural deposits; household pipes
 0.015 ppm

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Mercury
Natural deposits; refineries and factories; landfills;
crop fields
 0.002 ppm


Nitrite
Water running off fertilized fields; sewage leaks;
natural deposits
 10 ppm

HOW DO THEY TREAT OUR DRINKING
WATER

Water Treatment Process – Video

Water Treatment with “Splash” Video

Waste Water Treatment Video
HOW DO THEY TREAT OUR DRINKING
WATER
1.
2.
Water is piped from a river or lake
Water flows through mixers
1.
2.
3.
Water flows into clarifying pool to become clear
1.
4.
6.
The heavy lumps of dirt sink to the bottom and get
scraped away
Water flows through layers of coal, sand, and gravel
1.
5.
Clumping agents and disinfecting chemicals are added
The clumping agent makes dirt and bacteria clump
together
This filters out tiny particles of dust and dirt
Chlorine is added to kill the last of the bacteria
Water is pumped to your home
SEPTIC SYSTEM
Cleans water from homes or businesses
 There are two major parts

Septic Tank
 Drainfield

SEPTIC TANK


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Made generally from pre-cast concrete or fiberglass
There size depends on the estimated needs of the
home or business
Waste from toilets, sinks, washing machines, and
showers go here
Waste is separated into three general components
Solids or sludge
 Floatables or scum layer
 Zone of relatively clear water



Bacteria break solids into liquids
Oxygen-free conditions deactivate some of the disease
germs that are found in sewage
DRAINFIELD
The liquid from the septic tank flows into the
drainfield
 A series of perforated pipes or slotted panels that
are surrounded by a layer of gravel
 Here oxygen-using bacteria continue to
deactivate the disease germs in the wastewater
 Allows filtration of the wastewater as gravity
draws the water downwards through the soil
layers

WATER POLLUTION

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
If water gets a high enough concentration of different
chemicals, minerals, or organisms in it then it can no
longer be treated and cleaned
Human activity adds pollution to the water
Point-source pollution

Pollution that enters water from a known source




Sewage from a pipe
Chemicals from factories
Easy to spot and easy to stop
Nonpoint-source pollution

Pollution whose source is hard to find or is scattered

Run off from streets, farms, lawns, ext
Causes most of our water pollution
 Hard to enforce the laws

PREVENTING WATER POLLUTION
Don’t litter
 Use organic cleaners
 If you use nonorganic cleaners dispose of the
containers properly
 Use organic fertilizers

WATER IS USED IN FISHERIES AND
AQUACULTURE

Aquaculture

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The science and business of raising and harvesting
fish in a controlled situation.
Allows scientists to raise endangered species of fish
and release into the wild
Provide cheap, ready supply of catfish, trout, and
salmon
Any fish in the store that says farm raised
Fish can be feed steroids to make them grow faster
Fish can get sick and need medication
Fish farms can release excess nutrients and pollution
into rivers and lakes
Asian Carp
ASIAN CARP

Three species that threaten the Great Lakes
Bighead
 Silver
 Black
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Originally imported from Southeast Asia to help
with retention ponds in aquaculture and
wastewater treatment plants
 Flooding allowed them to escape

WATER SHORTAGES

Drought
A long period of abnormally low rainfall
 Can destroy crops
 Dry up water supplies
 Can cause wildfires


Overuse causes water shortages
The more people there is the more water is needed
 Clean usable fresh water is scarce
 If to many people pull water up from an aquifer it
will dry up
 Over use of rivers can cause them to run dry

HOW TO CONSERVE WATER
Turn water off when brushing your teeth
 Turn water off when doing the dishes
 Fix leaks in your house
 Water grass in the early morning or late at night
 Take shorter showers
 Wash full loads of clothes
 Run the dishwasher only when full
 Install low flow shower heads
 Install low flow toilets

SHARING WATER
It is important that we only use the amount of
water we need so others have it too
 If two places are sharing water from a river or
aquifer

The town up river uses more water then the town
downriver might not have enough
 Also true for pollution
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If the town up river pollutes the water then the town down
river will have polluted water
Often times treaties or laws are set up to control how
much water can be used by each place