Image Place Holder right
may think of pollution and contamination as being the same thing. Perhaps
in a general term, they are. But when it comes to specifically talking about
your water, the two, and their causes are very different.
is due to the influence or activities of people, where contamination may
be natural. There are many specific causes of water pollution, but before
we list the toppers, it's important to understand two broad categories
of water pollution: “Point source” — occurs when harmful substances are
emitted directly into a body of water. “Nonpoint source” — delivers pollutants
indirectly through transport or environmental change.
example of a point source of water pollution is a pipe from an industrial
facility discharging effluent directly into a river. An example of a nonpoint-source
of water pollution is when fertilizer from a farm field is carried into
a stream by rain (i.e. run-off). Point-source pollution is usually monitored
and regulated, at least in Western countries, though political factors
may complicate how successful efforts are at true pollution control. Nonpoint
sources are much more difficult to monitor and control, and today they
account for the majority of contaminants in streams and lakes.
are many sources of water pollution; some being oil spills, pesticides
and herbicidal usage and clear-cutting of forestry. But by and large,
an annual offender is clearly industrial chemical pollution. Almost all
bodies of water in the world have some level of pollution from chemicals
and industrial waste. In the United States, 34 billion liters per year
(60%) of the most hazardous liquid waste—solvents, heavy metals, and radioactive
materials—is injected directly into deep groundwater via thousands of
the EPA requires that these effluents be injected below the deepest source
of drinking water, some pollutants have already entered underground water
supplies in Florida, Texas, Ohio, and Oklahoma. The US is not alone in
careless treatment of its groundwater. In the late 1990s, India's Central
Pollution Control Board found that groundwater was unfit for drinking
in all 22 major industrial zones it surveyed.
the other hand, water contamination is often used to refer to impurities
in water regardless of the source or events that led to the impurities
being in the water. A common impurity or contamination in water is its
TDS count. Total Dissolved Solids (TDS) consist mainly of carbonates,
dissolved bicarbonates, chlorides, sulfates, phosphates, nitrates, calcium,
magnesium, sodium, potassium, iron, manganese, and a few others. They
do not include gases, colloids, or sediment. The TDS can be estimated
by measuring the specific conductance of the water. Dissolved solids in
natural waters range from less than 10 mg/l for rain to more than 100,000
mg/l for brines. Since TDS is the sum of all materials dissolved in the
water, it has many different mineral sources.
Image Place Holder left
Turbidity is often a contaminant or impurity of waters. Turbidity is the
term given to anything that is suspended in a water supply. It is found
in most surface waters, but usually doesn't exist in ground waters except
in shallow wells and springs after heavy rains. Turbidity gives the water
a cloudy appearance or shows up as dirty sediment. Undissolved materials
such as sand, clay, silt or suspended iron contribute to turbidity. Turbidity
can cause the staining of sinks and fixtures as well as the discoloring
of fabrics. Usually turbidity is measured in NTUs (nephelometric turbidity
units). Typical drinking water will have a turbidity level of 0 to 1 NTU.
Turbidity can also be measured in ppm (parts per million) and it's size
is measured in microns. Turbidity can be particles in the water consisting
of finely divided solids, larger than molecules, but not visible by the
naked eye; ranging in size from .001 to .150 mm (1 to 150 microns). The
US EPA has established an MCL for turbidity to be 0.5 to 1.0 NTU, because
it interferes with disinfection of the water.
treatment for turbidity can be reduced to 75 microns with a cyclone separator,
then reduced down to 20 micron with standard backwashable filter, however
flow rates of 5 gpm/ sq. ft. are recommended maximum. Turbidity can be
reduced to 10 micron with a multimedia filter while providing flow rates
of 15 gpm/sq. ft. Cartridge filters of various sizes are also available
down into the submicron range. Ultrafiltration also reduces the turbidity
levels of process water.
and large it is the man-made pollutions of waters that get the most attention,
and perhaps rightfully so. But what is also important is the overall contamination,
or natural quality of water that will help determine the treatments necessary
to make a water safe for public consumption.