3. Aeration: The water is mixed to liberate dissolved gases and to
suspended particles in the water column.
Flocculation: The materials and particles present in drinking water (clay,
organic material, metals, microorganisms) are often quite small and so will not
settle out from the water column without assistance. To help the settling
process along, "coagulating" compounds are added to the water, and
suspended particles "stick" to these compounds and create large and heavy
clumps of material.
Filtration: The water is run through a series of filters which trap and
remove particles still remaining in the water column. Typically, beds of sand or
charcoal are used to accomplish this task.
Disinfection: The water, now largely free of particles and microorganisms,
is treated to destroy any remaining disease-causing pathogens. This is
commonly done with chlorination or ultraviolet radiation.
22. Other Metals
Trace Metals required metabolic catalysts
Manganese
Iron
Cobalt
Copper
Zinc
Molybdenum
Chromium
Toxicity = > 40 x requirement
23. Nitrates
MCL = 10 mg/L
NO3
-
Agriculture
Organic Waste Disposal
NO3
- NO2
-
Methemoglobin is a form of hemoglobin that does not bind oxygen.
bacteria
Infants under 6 months are particularly susceptible
29. Ion Exchange Filters
Neg. Charge
Na Na
Na
Na
Na
Na
Na
Na
Pb2+, Hg2+
Neg charge
Na
Na
Na
Na
Pb2+
Hg2+
Na
Na
Na
Na
Na
Na
Na
Na Na
4 Na+
Finite Capacity
Metals
30. The solid carbon block faucet mount filters are reasonably effective in
reducing contaminants.
These filters, by nature, are quite smalland because filter effectiveness is
dependent on contact time of the water with the filter media, a larger, high-quality
solid carbon block filter will be more effective at reducing contaminants at the
same flow rate.
a high-quality solid block activated carbon replacement filter will filter water for
between 7 and 10 cents per gallon. 2 gallons of filtered water per day would cost
between $50 and $100 per year
Most Common Filtration
Solid Carbon Block faucet mount filters
41. According to a NRDC study, U.S. consumers paid between 240
and 10,000 times more per gallon for bottled water than for tap water
For the price of one bottle of Evian, Americans
can receive 1,000 gallons of tap water
The global consumption of bottled water reached
41 billion gallons in 2004, up 57 percent in just five years.
More than 5 trillion gallons of bottled water is shipped internationally each year.
Supplying Americans with plastic water bottles for one
year consumes more than 47 million gallons of oil
The energy required to produce 33 billion liters is equivalent to 32-54 million barrels of oil
In 2007, US consumers purchased more
than 33 billion liters of bottled water
42. What’s the Source?
More than 25 percent of bottled water
comes from a public source.
If water is packaged as "purified" or "drinking water,"
It likely originated from a municipal water supply, and
unless the water has been “substantially” altered,
it must state on the label that the water comes
from a municipal source.
Both Aquafina (Pepsi) and Dasani (Coca-Cola)
originate from municipal water systems
National Resource Defense Council
43. Other terms used on the label about the source, such as “glacier water” or “mountain
water," are not regulated standards of identity and may not indicate that the water is
necessarily from a pristine area
Artesian water, groundwater, spring water, well water - water from an
underground aquifer which may or may not be treated. Well water and artesian
water are tapped through a well. Spring water is collected as it flows
spontaneously to the surface or via a borehole. Ground water can be either.
Distilled water - steam from boiling water is recondensed and bottled.
Distilling water kills microbes and removes water’s natural minerals
Drinking water – water intended for human consumption and sealed in bottles
or other containers with no ingredients except that it may optionally contain safe
and suitable disinfectants. Fluoride may be added within limitations
Purified water - water that originates from any source but has been treated to meet
the U.S. Pharmacopeia definition of purified water. Purified water is essentially free
of all chemicals. Reverse osmosis is often used.
44. Is it safe?
Most bottled water appears to be safe.
(NRDC independent testing of 1000 bottles)
EPA sets standards for tap water provided by public water
systems; the Food and Drug Administration sets bottled
water standards based on EPA's tap water standards
Most bottled water is treated more than tap water;
however, some is treated less or not treated at all .
About 22 percent of the brands tested by NRDC contained,
in at least one sample, some chemical contaminant
45. can leach into bottled water overtime.
polyethylene terephthalate (PET) bottles
PET
phthalates
known to disrupt testosterone and other hormones,
One study found that water that had been stored for 10 weeks in
plastic bottles contained phthalates, suggesting that the chemicals
could be coming from the bottle, the plastic cap or the liner
It also appears possible that some as-yet unidentified
chemicals in plastics have the potential to interfere
with estrogen and other reproductive hormones
46. The study stressed that amounts of antimony were well below
official recommended levels. But it also discovered that the
levels almost doubled when the bottles were stored for three months
The study collected 48 brands of water in PET bottles from its source
in the ground at a German bottling plant. The water had 4 ppt of
antimony before being bottled, the contents of a new bottle had
360 ppt and one opened three months later had 700 ppt.
The health effects of antimony ingestion are not well known
Royal Society of Chemistry Publication
Antimony
The U.S. EPA has established 6.0 parts per billion (ppb) as a safe level
47. 88% of water bottles are not recycled
In 2005, 2 million tons of plastic water bottles were not recycled
In 2006, 2 billion half-liter bottles of water were shipped to U.S. ports
Where are all the old bottles?