Aeration The process of adding air to water. In wastewater treatment, air is added
to refresh wastewater and to keep solids in suspension. With mixtures of wastewater and activated sludge, adding air provides mixing and oxygen for the
microorganisms treating the wastewater.
Aerobes Bacteria that must have molecular (dissolved) oxygen (DO) to survive.
Aerobic bacteria These bacteria live, remove BOD, and reproduce themselves
under aerobic environmental conditions containing sufficient dissolved oxygen
(DO).
Aerobic digestion The process equipment of aerobic digestion is similar to that of
the activated sludge process. Aerobic digestion is not a suspended-growth biological process in principle, and is for sludge treatment (not for wastewater
treatment). It is a suspended-destruction biological process. In the presence of
oxygen, the biodegradable matter in the activated sludge (biosolids) is oxidized,
destroyed, and converted to carbon dioxide and water. Oxygen must be supplied
in direct proportion to the mass of volatile solids (VSs) destroyed. Sludge
stabilization is not complete until there has been an extended period of primarily
endogenous respiration (15 to 20 days).
Aerobic An environmental condition in which free and dissolved oxygen is available in an aqueous environment (For instance, nitrification is an aerobic process).
Aerosols Small particles or liquid droplets in the atmosphere that can absorb or
reflect sunlight depending on their composition.
Afforestation Planting of new forests on lands that historically have not contained
forests.
After-action findings Documented results of what in your emergency plan worked
and did not work after an incident happens. These findings are used to improve
your plan and procedures.
Air lift It is a type of pump. This device consists of a vertical riser pipe in the
wastewater or sludge to be pumped. Compressed air is injected into a tall piece at
the bottom of the pipe. Fine air bubbles mix with the wastewater or sludge to form
a mixture lighter than the surrounding water, which causes the mixture to rise in
the discharge pipe to the outlet. An air lift pump works like the center of a stand in
a percolator coffee pot.
Albedo The amount of solar radiation reflected from an object or surface, often
expressed as a percentage.
Algae They are microscopic plants, which contain chlorophyll and live floating or
are suspended in water. They also may be attached to structures, rocks, or other
similar substances. Algae produce oxygen during sunlight hours and use oxygen
during night hours. Their biological activities appreciably affect the pH and
dissolve oxygen of the water.
Aliquot It is a portion of a sample, which is often an equally divided portion of a
sample.
Alkali bee (Nomia melanderi) These bees are important pollinators, especially of
alfalfa. Reared in large numbers, the bees are released in areas near this crop,
resulting in a greatly increased yield of alfalfa. Each female takes about 30 days to
build a single nest of about 20 cells. The bees hibernate in the prepupa stage and
complete their life cycle the second year.
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to refresh wastewater and to keep solids in suspension. With mixtures of wastewater and activated sludge, adding air provides mixing and oxygen for the
microorganisms treating the wastewater.
Aerobes Bacteria that must have molecular (dissolved) oxygen (DO) to survive.
Aerobic bacteria These bacteria live, remove BOD, and reproduce themselves
under aerobic environmental conditions containing sufficient dissolved oxygen
(DO).
Aerobic digestion The process equipment of aerobic digestion is similar to that of
the activated sludge process. Aerobic digestion is not a suspended-growth biological process in principle, and is for sludge treatment (not for wastewater
treatment). It is a suspended-destruction biological process. In the presence of
oxygen, the biodegradable matter in the activated sludge (biosolids) is oxidized,
destroyed, and converted to carbon dioxide and water. Oxygen must be supplied
in direct proportion to the mass of volatile solids (VSs) destroyed. Sludge
stabilization is not complete until there has been an extended period of primarily
endogenous respiration (15 to 20 days).
Aerobic An environmental condition in which free and dissolved oxygen is available in an aqueous environment (For instance, nitrification is an aerobic process).
Aerosols Small particles or liquid droplets in the atmosphere that can absorb or
reflect sunlight depending on their composition.
Afforestation Planting of new forests on lands that historically have not contained
forests.
After-action findings Documented results of what in your emergency plan worked
and did not work after an incident happens. These findings are used to improve
your plan and procedures.
Air lift It is a type of pump. This device consists of a vertical riser pipe in the
wastewater or sludge to be pumped. Compressed air is injected into a tall piece at
the bottom of the pipe. Fine air bubbles mix with the wastewater or sludge to form
a mixture lighter than the surrounding water, which causes the mixture to rise in
the discharge pipe to the outlet. An air lift pump works like the center of a stand in
a percolator coffee pot.
Albedo The amount of solar radiation reflected from an object or surface, often
expressed as a percentage.
Algae They are microscopic plants, which contain chlorophyll and live floating or
are suspended in water. They also may be attached to structures, rocks, or other
similar substances. Algae produce oxygen during sunlight hours and use oxygen
during night hours. Their biological activities appreciably affect the pH and
dissolve oxygen of the water.
Aliquot It is a portion of a sample, which is often an equally divided portion of a
sample.
Alkali bee (Nomia melanderi) These bees are important pollinators, especially of
alfalfa. Reared in large numbers, the bees are released in areas near this crop,
resulting in a greatly increased yield of alfalfa. Each female takes about 30 days to
build a single nest of about 20 cells. The bees hibernate in the prepupa stage and
complete their life cycle the second year.
426
M.-H. S. Wang and L. K. Wang