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Oil Desulphurization
Pre-combustion method for reducing sulphur dioxide emissions
from oil-burning power plants. The oil is treated with hydrogen,
which removes some of the sulphur by forming hydrogen sulphide
gas.
Oil Spill
An accidental or intentional discharge of oil, which reaches
bodies of water. Can be controlled by chemical dispersion,
combustion, mechanical containment, and/or adsorption. Spills
from tanks and pipelines can also occur away from water
bodies, contaminating the soil, getting into sewer systems
and threatening underground water sources.
Opacity
The amount of light obscured e.g. by particulate pollution
in the air.
Optimization
Working in the most efficient or most desirable mode of
operation.
Oral
Spoken or communicated by mouth.
Organic Chemicals/Compounds
Animal or plant-produced substances containing mainly carbon,
hydrogen, nitrogen, and oxygen.
Organic Matter
Carbonaceous waste contained in plant or animal matter and
originating from domestic or industrial sources.Organic
1. Referring to or derived from living organisms. 2. In chemistry,
any compound containing carbon. Organism
Any form of animal or plant life.
Organophosphates
Pesticides that contain phosphorus; short-lived, but some
can be toxic when first applied.
Organotins
Chemical compounds used in anti-foulant paints to protect
the hulls of boats and ships, buoys, and pilings from marine
organisms such as barnacles.
Osmosis
The passage of a liquid from a weak solution to a more concentrated
solution across a semi-permeable membrane that allows passage
of the solvent (water) but not the dissolved solids.
Outfall
The place where effluent is discharged into receiving waters.
Ozone (O3)
Found in two layers of the atmosphere, the stratosphere and
the troposphere. In the stratosphere (the atmospheric layer
7 to 10 miles or more above the earths surface) ozone is a
natural form of oxygen that provides a protective layer shielding
the earth from ultraviolet radiation. In the troposphere (the
layer extending up 7 to 10 miles from the earth's surface),
ozone is a chemical oxidant and major component of photochemical
smog. It can seriously impair the respiratory system. Ozone
in the troposphere is produced through complex chemical reactions
of nitrogen oxides, which are among the primary pollutants
emitted by combustion sources; hydrocarbons, released into
the atmosphere through the combustion, handling and processing
of petroleum products; and sunlight.
Ozone depletion
Destruction of the stratospheric ozone layer, which shields
the earth from ultraviolet radiation harmful to life. This
destruction of ozone is caused by the breakdown of certain
chlorine and/or bromine containing compounds (chlorofluorocarbons
or halons), which break down when they reach the stratosphere
and then catalytically destroy ozone molecules.
Ozone Hole
Thinning break in the stratospheric ozone layer. Designation
of amount of such depletion as a "ozone hole"
is made when detected amount of depletion exceeds fifty
percent. Seasonal ozone holes have been observed over both
the Antarctic region and the Arctic region and part of Canada
and the extreme north-eastern United States.
Ozone Layer
The protective layer in the atmosphere, about 15 miles above
the ground, that absorbs some of the sun's ultraviolet rays,
thereby reducing the amount of potentially harmful radiation
reaching the earth's surface.
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