Download Topic 6 :Water Quality and Management

Topic 6 :Water Quality and
Management
Dissolved in Water




Hard water contains dissolved minerals like
calcium, lime, fluoride, and magnesium that
often form scaly deposits on faucets and tiles
as water evaporates and leaves behind the
minerals.
These deposits can be removed by solvents
like CLR
Soft water has less calcium and magnesium in
it. Water softeners are added to make it
soft
Oxygen, CO2, sediments, phosphate, nitrogen,
sulfur, and some other chemicals can be found
dissolved in water.
Bad stuff in water…



Toxic substances are materials added to the
environment that harms it or other organisms.
(ex) PCB – used in making electronics
DDT – used as pesticide
CFC – used in fridgerants a/c, destroys O3
Sulfur dioxide (SO2) and nitrogen oxides
(NO) are released into the air from burning
fossil fuels. They come down in raindrops as
acid rain.
Over time, the build up of these acids in the
water and soil decrease the pH (level of
acidity) affecting organisms’ lifecycles,
reproduction, cells, developement
The pH scale
Normal rain 6
Human blood 7.4
Bioindicators



The health of the environment can be evaluated
by looking at bioindicator species sensitive to
changes in the environment.
(ex) insect larvae, northern leopard frog,
salamanders, fish, clams, snails, algae
Changes to their development and lifecycles
give us indication of problems, pollutants
Contaminants in the environment can make their
way into the food chain and affect top
predators like humans through bioaccumulation
Purifying Water

To make water potable (safe for drinking), it
has to go through water treatment. See
diagram on page 463
WATER INTAKE FROM RIVER
LIME, ALUM, CHARCOAL ADDED TO WATER AT TREAMENT PLANT TO REMOVE
DIRT AND SEDIMENTS.
WATER PUMPED THROUGH SAND AND GRAVEL TO FILTER OUT FURTHER PARTICLES
CHLORINE AND OZONE ADDED TO KILL ANY BACTERIA LEFT. FLUORIDE ADDED
Sewage


Sewage is the waste from homes, businesses,
industries. Basically what goes down toilets
and sinks and drains.
What happens to sewage?
SEWAGE IS PUMPED TO SEWAGE TREATMENT PLANT
SEWAGE IS FILTERED TO REMOVE LARGER PARTICLES. CHEMICALS
ADDED TO KILL BACTERIA, REMOVE SMELL, AND SMALLER PARTICLES
THE “CLEANED” WATER IS NOW CALLED EFFLUENT AND PUMPED BACK
INTO THE RIVER
A gorgeous garden on Phi Phi island Thailand….but what was that smell????
Oh……

In rural areas with no access to sewage
treatment, sewage is collected in septic tanks
for trucks to collect
New Sources of Water



As fresh water supplies dwindle, we look to
the sea for more water to desalinate
Giant distillation stations separates the salt
from the water.
Water can also be put through reverse
osmosis.
Pressure pushes
water through
membrane
Purified water
Semipermeable
membrane