Transcript drinking water - Horace Mann Webmail

Water to Drink
Where does our drinking water
come from?
In the U.S., drinking water comes from:
1. Public or private reservoirs
2. Private wells
No matter where water comes from, it needs some treatment
before we drink it to be sure it is safe.
To see if water is safe to drink, it is tested for:
1. Water quality - cloudiness, odor and color
2. PH - measures the acidity of water; pure water is neutral and
would measure 7 on the pH scale
3. Hardness - the level of calcium and magnesium
Hard water does not form suds well with soap and can leave
deposits.
4. Disease-Causing Organisms - such as E. coli, a bacteria found
in human and animal waste
The EPA (Environmental protection Agency) has developed
water quality standards.
These standards set limits for certain chemicals, minerals and
bacteria in drinking water.
A concentration is the amount of one substance dissolved in another.
In a typical water treatment plant,
the first step is filtration.
The water passes through a series of screens to remove
large objects.
The second step is coagulation.
A chemical is added that causes particles to stick together and
sink to the bottom in clumps.
These clumps can be filtered out.
The third step is chlorination.
Chlorine is added to kill disease-causing microorganisms.
In NYC, fluoride is also added to the water.
Water quality is tested every day.
Once treated, the water can be distributed for drinking.
It goes to a central pumping station.
From the pumping station, the water goes into smaller pipes.
It is carried through the pipes by water pressure.
Some communities use a water tower rather than a pumping station.