Thermal discharge An industrial, agricultural, or commercial discharge of heated
liquid (such as wastewater, or gas, or steam from a factory) into natural waters or
air at a temperature harmful to the environment.
Thermal expansion The increase in volume (and decrease in density) that results
from warming water. A warming of the ocean leads to an expansion of the ocean
volume, which leads to an increase in sea level.
Thermal stabilization A heating process for metal incorporation into certain stable
products.
Thermohaline circulation Large-scale density-driven circulation in the ocean,
caused by differences in temperature and salinity. In the North Atlantic, the
thermohaline circulation consists of warm surface water flowing northward and
cold deep water flowing southward, resulting in a net poleward transport of heat.
The surface water sinks in highly restricted sinking regions located in high
latitudes.
Thickener, flotation A tank or basin in which liquid sludge is held for a period of
time during which most of the lighter air-sludge flocs float to the liquid surface as
the concentrated-thickened sludge and very small amount of the very heavier
solids will settle to the tank bottom.
Thickener, gravity A tank or basin in which liquid sludge is held for a period of
time during which most of the heavier solids settle to the tank bottom as the
concentrated-thickened sludge and very small amount of the lighter solids will
float to the water surface as the scum.
Thickening, sludge Sludge thickening is employed prior to subsequent sludge
dewatering processes to increase the efficiency of the sludge dewatering equipment. There are at least five types of sludge thickening processes: gravity
thickening, flotation thickening, centrifuge thickening, gravity belt thickening,
and rotary drum thickening.
Threat Natural, technological, or human-caused occurrence, individual, entity, or
action that has or indicates the potential to harm life, information, operations, the
environment, and/or property.
Thunderstorm A storm with thunder and lightning, often accompanied by rain
or hail.
Tidal rivers (a) A tidal river is a river, or more typically a stretch of a river, whose
flow and level is influenced by tides; (b) a river that enters a sea or estuary and is
thus affected by tides.
Tornado A violent, rotating column of air that extends between, and is in contact
with, the ground and a cloud.
Total Kjeldahl nitrogen (TKN) The combined amount of organic and ammonia
nitrogen determined by a laboratory analysis.
Total nitrogen (TN) All forms of nitrogen including ammonia nitrogen, nitrate
nitrogen, nitrite nitrogen, and organic nitrogen.
Total phosphorus (TP) All forms of phosphorus, including orthophosphate,
polyphosphates, and organic phosphorus.
Toxic A substance which is poisonous to a living organism.
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liquid (such as wastewater, or gas, or steam from a factory) into natural waters or
air at a temperature harmful to the environment.
Thermal expansion The increase in volume (and decrease in density) that results
from warming water. A warming of the ocean leads to an expansion of the ocean
volume, which leads to an increase in sea level.
Thermal stabilization A heating process for metal incorporation into certain stable
products.
Thermohaline circulation Large-scale density-driven circulation in the ocean,
caused by differences in temperature and salinity. In the North Atlantic, the
thermohaline circulation consists of warm surface water flowing northward and
cold deep water flowing southward, resulting in a net poleward transport of heat.
The surface water sinks in highly restricted sinking regions located in high
latitudes.
Thickener, flotation A tank or basin in which liquid sludge is held for a period of
time during which most of the lighter air-sludge flocs float to the liquid surface as
the concentrated-thickened sludge and very small amount of the very heavier
solids will settle to the tank bottom.
Thickener, gravity A tank or basin in which liquid sludge is held for a period of
time during which most of the heavier solids settle to the tank bottom as the
concentrated-thickened sludge and very small amount of the lighter solids will
float to the water surface as the scum.
Thickening, sludge Sludge thickening is employed prior to subsequent sludge
dewatering processes to increase the efficiency of the sludge dewatering equipment. There are at least five types of sludge thickening processes: gravity
thickening, flotation thickening, centrifuge thickening, gravity belt thickening,
and rotary drum thickening.
Threat Natural, technological, or human-caused occurrence, individual, entity, or
action that has or indicates the potential to harm life, information, operations, the
environment, and/or property.
Thunderstorm A storm with thunder and lightning, often accompanied by rain
or hail.
Tidal rivers (a) A tidal river is a river, or more typically a stretch of a river, whose
flow and level is influenced by tides; (b) a river that enters a sea or estuary and is
thus affected by tides.
Tornado A violent, rotating column of air that extends between, and is in contact
with, the ground and a cloud.
Total Kjeldahl nitrogen (TKN) The combined amount of organic and ammonia
nitrogen determined by a laboratory analysis.
Total nitrogen (TN) All forms of nitrogen including ammonia nitrogen, nitrate
nitrogen, nitrite nitrogen, and organic nitrogen.
Total phosphorus (TP) All forms of phosphorus, including orthophosphate,
polyphosphates, and organic phosphorus.
Toxic A substance which is poisonous to a living organism.
12 Glossary of Natural Resources and Environmental Pollution Control
489