Sink Any process, activity, or mechanism, which removes a greenhouse gas, an
aerosol or a precursor of a greenhouse gas or aerosol from the atmosphere.
Sintering Using heat or pressure to form a solid mass of material, without melting
the material to the point of liquefying.
Sludge (a) The settleable solids separated from liquids during processing. (b) The
deposits of foreign material on the bottoms of streams or other bodies of water.
Sludge age (SA) SA is the length of time a particle of activated sludge stays in the
biological treatment plant, measured in days. In a biological phosphorus removal
plant, sludge age is the amount (pound or kilogram) of mixed liquor suspended
solids in all the biological reactors divided by the suspended solids withdrawn
from the system per day (pound per day of waste activated sludge, or kilogram per
day of waste activated sludge).
Sludge dewatering Sludge dewatering is the second step of sludge handling, after
sludge thickening. Sludge dewatering is required for all facilities that do not
dispose of their sludge in liquid form. It is a physical (mechanical) process to
reduce the moisture content of sludge. The purpose is to reduce sludge volume, in
turn, to reduce subsequent sludge digestion costs and/or final sludge disposal
(land disposal or incineration) costs. Dewatering is usually required prior to
sludge incineration. There are a variety of dewatering processes available:
(a) vacuum filtration; (b) centrifuge; (c) belt filter press; (d) plate and frame
press; (e) sludge drying beds or infrared sludge dryer; (f) sludge lagoons.
Sludge digestion The process of changing organic matter in sludge into a gas or
liquid or a more stable solid form. These changes take place as microorganisms
feed on sludge in anaerobic (more common) or aerobic digesters.
Sludge dryer, infrared It is a sludge dewatering process using regular direct
radiant energy from infrared heating elements. Dewatered sludge is transferred
from the dewatering equipment to the dryer by a conveyor belt. The sludge then
drops into the augers, where the auger blades agitate the sludge, while infrared
heating elements heat the sludge. This process then repeats once the sludge is
dropped into the secondary drying zone.
Sludge dryer, microwave It is a new sludge dewatering process developed by
Lawrence K. Wang of the Lenox Institute of Water Technology involving the use
of microwave energy from a microwave dryer. Dewatered sludge is transferred
from the dewatering equipment to the dryer by a conveyor belt. The sludge then
drops into the augers, where the auger blades agitate the sludge, while microwaves heat and dewater the sludge. This process then repeats once the sludge is
dropped into the secondary drying zone.
Sludge drying beds It is a sludge dewatering process using solar energy to evaporate water from the sludge slurries.
Sludge handling It includes every required processes or management regarding
waste sludge, such as sludge thickening, sludge dewatering, sludge digestion,
sludge storage, sludge transportation, sludge disposal, etc.
Sludge lagoons It is an earthen basin used for holding and dewatering sludge
slurries by solar energy.
12 Glossary of Natural Resources and Environmental Pollution Control
483
aerosol or a precursor of a greenhouse gas or aerosol from the atmosphere.
Sintering Using heat or pressure to form a solid mass of material, without melting
the material to the point of liquefying.
Sludge (a) The settleable solids separated from liquids during processing. (b) The
deposits of foreign material on the bottoms of streams or other bodies of water.
Sludge age (SA) SA is the length of time a particle of activated sludge stays in the
biological treatment plant, measured in days. In a biological phosphorus removal
plant, sludge age is the amount (pound or kilogram) of mixed liquor suspended
solids in all the biological reactors divided by the suspended solids withdrawn
from the system per day (pound per day of waste activated sludge, or kilogram per
day of waste activated sludge).
Sludge dewatering Sludge dewatering is the second step of sludge handling, after
sludge thickening. Sludge dewatering is required for all facilities that do not
dispose of their sludge in liquid form. It is a physical (mechanical) process to
reduce the moisture content of sludge. The purpose is to reduce sludge volume, in
turn, to reduce subsequent sludge digestion costs and/or final sludge disposal
(land disposal or incineration) costs. Dewatering is usually required prior to
sludge incineration. There are a variety of dewatering processes available:
(a) vacuum filtration; (b) centrifuge; (c) belt filter press; (d) plate and frame
press; (e) sludge drying beds or infrared sludge dryer; (f) sludge lagoons.
Sludge digestion The process of changing organic matter in sludge into a gas or
liquid or a more stable solid form. These changes take place as microorganisms
feed on sludge in anaerobic (more common) or aerobic digesters.
Sludge dryer, infrared It is a sludge dewatering process using regular direct
radiant energy from infrared heating elements. Dewatered sludge is transferred
from the dewatering equipment to the dryer by a conveyor belt. The sludge then
drops into the augers, where the auger blades agitate the sludge, while infrared
heating elements heat the sludge. This process then repeats once the sludge is
dropped into the secondary drying zone.
Sludge dryer, microwave It is a new sludge dewatering process developed by
Lawrence K. Wang of the Lenox Institute of Water Technology involving the use
of microwave energy from a microwave dryer. Dewatered sludge is transferred
from the dewatering equipment to the dryer by a conveyor belt. The sludge then
drops into the augers, where the auger blades agitate the sludge, while microwaves heat and dewater the sludge. This process then repeats once the sludge is
dropped into the secondary drying zone.
Sludge drying beds It is a sludge dewatering process using solar energy to evaporate water from the sludge slurries.
Sludge handling It includes every required processes or management regarding
waste sludge, such as sludge thickening, sludge dewatering, sludge digestion,
sludge storage, sludge transportation, sludge disposal, etc.
Sludge lagoons It is an earthen basin used for holding and dewatering sludge
slurries by solar energy.
12 Glossary of Natural Resources and Environmental Pollution Control
483