effluent; (b) floated activated sludge, returned from the top of flotation clarifiers,
to mix with incoming raw or primary effluent.
Reunification A process to ensure that children are safely reunited with parents or
legal guardians when an emergency occurs.
Riparian It is an environment of, relating to, or situated on the banks of a river.
Rising sludge Rising sludge occurs in the secondary clarifiers of activated sludge
plants when the sludge settles to the bottom of the clarifier, is compacted, and
then starts to rise to the surface, usually as a result of denitrification.
Risk management In business, or science, or engineering, the forecasting and
evaluation of public health, environmental, financial risks together with the
identification of procedures to avoid or minimize their impact.
River dredging The most common use for cutter suction dredge equipment. River
projects vary in purpose. Some river dredging projects work to maintain adequate
channel depths, while others are aimed at flood control and mitigation.
Robbing It is an action of stealing nectar or honey by bees from other colonies,
which occurs more often during a nectar dearth.
Rotary drum thickening It is sludge preliminary concentration process for
removal of water from dilute sludge using a rotary screen drum. In operation,
polymer is mixed with dilute sludge, and the conditioned sludge is then passed
through rotating screen drums, which separate the flocculated solids from water.
Thickened sludge rolls out the end of the drums, while separated water decants
through the screens.
Rotating biological contactor (RBC) In an RBC system, a series of closely spaced
circular polystyrene or polyvinyl chloride disks is partially submerged in wastewater. Biological growth (biomass) attached to the surface of the disks. The
biomass is kept in aerobic conditions (if carbonaceous oxidation and nitrification
are intended), or anoxic conditions (if denitrification is intended) by rotation of
the disks. Aerobic RBC is opened, so biomass may utilize the oxygen in the air,
while anoxic RBC for denitrification is normally closed to block off the air. The
RBC effluent discharges to a clarifier (either a sedimentation clarifier or a flotation
clarifier) for solid-water separation, returning sludge, wasting sludge, and clarifier
effluent discharge.
Salmon (a) A large edible fish that is a popular game fish, much prized for its pink
flesh. Salmon mature in the sea but migrate to freshwater streams to spawn.
(b) Salmon is the common name for several species of ray-finned fish in the
family Salmonidae. Other fish in the same family include trout, char, grayling,
and whitefish. Salmon are native to tributaries of the North Atlantic and Pacific
Ocean. (c) Representatives of salmon are sockeye salmon, Atlantic salmon,
Chinook salmon, Coho salmon, and pink salmon.
Salt water intrusion Displacement of fresh or ground water by the advance of salt
water due to its greater density, usually in coastal and estuarine areas.
Sample A part of a larger whole or a single item of a group; a finite part or subset of
a statistical population. A sample serves to provide data or information
concerning the properties of the whole group or population.
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to mix with incoming raw or primary effluent.
Reunification A process to ensure that children are safely reunited with parents or
legal guardians when an emergency occurs.
Riparian It is an environment of, relating to, or situated on the banks of a river.
Rising sludge Rising sludge occurs in the secondary clarifiers of activated sludge
plants when the sludge settles to the bottom of the clarifier, is compacted, and
then starts to rise to the surface, usually as a result of denitrification.
Risk management In business, or science, or engineering, the forecasting and
evaluation of public health, environmental, financial risks together with the
identification of procedures to avoid or minimize their impact.
River dredging The most common use for cutter suction dredge equipment. River
projects vary in purpose. Some river dredging projects work to maintain adequate
channel depths, while others are aimed at flood control and mitigation.
Robbing It is an action of stealing nectar or honey by bees from other colonies,
which occurs more often during a nectar dearth.
Rotary drum thickening It is sludge preliminary concentration process for
removal of water from dilute sludge using a rotary screen drum. In operation,
polymer is mixed with dilute sludge, and the conditioned sludge is then passed
through rotating screen drums, which separate the flocculated solids from water.
Thickened sludge rolls out the end of the drums, while separated water decants
through the screens.
Rotating biological contactor (RBC) In an RBC system, a series of closely spaced
circular polystyrene or polyvinyl chloride disks is partially submerged in wastewater. Biological growth (biomass) attached to the surface of the disks. The
biomass is kept in aerobic conditions (if carbonaceous oxidation and nitrification
are intended), or anoxic conditions (if denitrification is intended) by rotation of
the disks. Aerobic RBC is opened, so biomass may utilize the oxygen in the air,
while anoxic RBC for denitrification is normally closed to block off the air. The
RBC effluent discharges to a clarifier (either a sedimentation clarifier or a flotation
clarifier) for solid-water separation, returning sludge, wasting sludge, and clarifier
effluent discharge.
Salmon (a) A large edible fish that is a popular game fish, much prized for its pink
flesh. Salmon mature in the sea but migrate to freshwater streams to spawn.
(b) Salmon is the common name for several species of ray-finned fish in the
family Salmonidae. Other fish in the same family include trout, char, grayling,
and whitefish. Salmon are native to tributaries of the North Atlantic and Pacific
Ocean. (c) Representatives of salmon are sockeye salmon, Atlantic salmon,
Chinook salmon, Coho salmon, and pink salmon.
Salt water intrusion Displacement of fresh or ground water by the advance of salt
water due to its greater density, usually in coastal and estuarine areas.
Sample A part of a larger whole or a single item of a group; a finite part or subset of
a statistical population. A sample serves to provide data or information
concerning the properties of the whole group or population.
478
M.-H. S. Wang and L. K. Wang