can biologically decompose into inorganic orthophosphate; other types are
non-biodegradable and will pass through the wastewater system without
treatment.
Organic solvent A carbon-based solvent that is capable of dissolving other
substances.
Ortho Imagery It is the aerial photograph that has been rectified to produce an
accurate image of the Earth by removing tilt and relief displacements, which
occurred when the photo was taken.
Orthophosphate It is an inorganic nutrient containing phosphorus which is
required for plant and animal growth. An inorganic, soluble form of phosphorus
that is readily available to plants and animals without further breakdown, and
accounts for 70–90% of total phosphorus in wastewater. The easiest form of
phosphorus that can be treated chemically. Total phosphorus includes orthophosphate, polyphosphate and organic phosphate.
OSHA It stands for the Occupational Safety and Health Administration of the
United States Department of Labor, formed by the Occupational Safety and
Health Act of 1970.
Output rating It refers to the percent of solid material production which may be
expected from the dredge under normal operating conditions. Not to be confused
with such phrases as output capacity, which usually refers to theoretical pumping
output which could be more than twice as much under certain conditions.
Oxic It is an environmental condition in which an aquatic environment contains
limited dissolved oxygen only in the range of 1.5 to 2.0 mg/L.
Oxidation ditch It is a ring-shaped channel suspended-growth biological process
system similar to extended aeration process for mainly carbonaceous oxidation
and nitrification. It was developed to minimize waste-activated sludge production
through endogenous decay of the sludge mass. It is equipped with mechanical
aeration devices, such as, mechanical brush aerators surface aerators and jet
aerator devices to aerate and pump the wastewater. Screened wastewater enters
the ditch is aerated, and circulates at about 0.8 to 1.2 ft./sec. The economics of
oxidation ditches appear most favorable when the solids retention time (SRT) is
long, particularly where nitrification is required. When both nitrification and
denitrification are required, certain portion of the ditch must be operated under
anoxic condition (instead of normal aerobic oxidation condition), the process
should be renamed as “oxidation-denitrification ditch.”
Oxidation reduction potential (ORP) The potential required to transfer electrons
from the oxidant to the reductant; the quantitative measure, in mV, of the state of
oxidation in wastewater treatment.
Oxidation The addition of oxygen, removal of hydrogen, or removal of electrons
from a compound (For instance, organic matter may be oxidized to a more stable
compound).
Oxidize To chemically transform a substance by combining it with oxygen.
Ozonation It is an oxidation process or a disinfection process, or both, involving
the use of ozone.
12 Glossary of Natural Resources and Environmental Pollution Control
469
non-biodegradable and will pass through the wastewater system without
treatment.
Organic solvent A carbon-based solvent that is capable of dissolving other
substances.
Ortho Imagery It is the aerial photograph that has been rectified to produce an
accurate image of the Earth by removing tilt and relief displacements, which
occurred when the photo was taken.
Orthophosphate It is an inorganic nutrient containing phosphorus which is
required for plant and animal growth. An inorganic, soluble form of phosphorus
that is readily available to plants and animals without further breakdown, and
accounts for 70–90% of total phosphorus in wastewater. The easiest form of
phosphorus that can be treated chemically. Total phosphorus includes orthophosphate, polyphosphate and organic phosphate.
OSHA It stands for the Occupational Safety and Health Administration of the
United States Department of Labor, formed by the Occupational Safety and
Health Act of 1970.
Output rating It refers to the percent of solid material production which may be
expected from the dredge under normal operating conditions. Not to be confused
with such phrases as output capacity, which usually refers to theoretical pumping
output which could be more than twice as much under certain conditions.
Oxic It is an environmental condition in which an aquatic environment contains
limited dissolved oxygen only in the range of 1.5 to 2.0 mg/L.
Oxidation ditch It is a ring-shaped channel suspended-growth biological process
system similar to extended aeration process for mainly carbonaceous oxidation
and nitrification. It was developed to minimize waste-activated sludge production
through endogenous decay of the sludge mass. It is equipped with mechanical
aeration devices, such as, mechanical brush aerators surface aerators and jet
aerator devices to aerate and pump the wastewater. Screened wastewater enters
the ditch is aerated, and circulates at about 0.8 to 1.2 ft./sec. The economics of
oxidation ditches appear most favorable when the solids retention time (SRT) is
long, particularly where nitrification is required. When both nitrification and
denitrification are required, certain portion of the ditch must be operated under
anoxic condition (instead of normal aerobic oxidation condition), the process
should be renamed as “oxidation-denitrification ditch.”
Oxidation reduction potential (ORP) The potential required to transfer electrons
from the oxidant to the reductant; the quantitative measure, in mV, of the state of
oxidation in wastewater treatment.
Oxidation The addition of oxygen, removal of hydrogen, or removal of electrons
from a compound (For instance, organic matter may be oxidized to a more stable
compound).
Oxidize To chemically transform a substance by combining it with oxygen.
Ozonation It is an oxidation process or a disinfection process, or both, involving
the use of ozone.
12 Glossary of Natural Resources and Environmental Pollution Control
469