(or float). The retention time in the flotation chambers is usually about 20–60 minutes for rectangular flotation clarifier, and about 3–15 minutes for circular
flotation clarifier using zero-horizontal velocity design. The effectiveness of
dissolved air flotation depends upon the attachment of bubbles to the suspended
solids and/or oil, which are to be removed from the waste stream. The attraction
between the air bubble and particle is primarily a result of the particle surface
charge and bubble-size distribution. The more uniform the distribution of water
and microbubbles, the shallower the flotation clarifier can be. Generally, the depth
of effective flotation units is between 3 and 9 feet.
Primary sedimentation clarification It is a unit process or unit operation for
removal of mainly total suspended solids (settleable solids and floatable solids)
from screened wastewater using a primary sedimentation clarifier.
Primary sedimentation clarifier It is a tank used to settle mainly total suspended
solids (TSSs) from screened raw wastewater by gravity. The main objectives of a
primary sedimentation clarifier are removal of settleable solids by settling them to
the clarifier bottom, and removal of floatable solids by skimming them from the
clarifier’s wastewater surface. In a rectangular sedimentation clarifier, the wastewater flows from one end to the other and the settled sludge is moved to a hopper
at on end, either by scrapers called “flights” set on parallel chains, or by a single
bottom scraper set on a traveling bridge. Floating materials, such as grease and
oil, are collected by a surface skimmer and then removed from the rectangular
sedimentation clarifier. In a circular sedimentation clarifier, the wastewater usually enters in the middle and flows toward the outside edge. Settled sludge is
pushed to the hopper that is in the middle of the circular clarifier’s tank bottom.
Floating material is removed by a surface skimmer connected to the sludge
collector.
Primary swarm It is the first swarm to leave the parent colony, usually with the old
queen (see secondary swarm).
Primary treatment It is an important wastewater treatment step (either primary
sedimentation clarification or primary flotation clarification mainly for removing
total suspended solids from preliminary treatment effluent) after the preliminary
treatment (i.e., bar screen, comminutor, and grit chamber mainly for removing
large objects from raw wastewater), but before secondary treatment (either
biological treatment or physicochemical treatment mainly for removing dissolved
organic/inorganic pollutants from primary effluent).
Procedure A set of systematic instructions for performing an operation.
Propolis (a) It is called bee glue, which is sap or resinous material that is collected
from trees or plants by bees and used to strengthen the comb and to seal cracks.
(b) They are sap or resinous materials collected from trees or plants by bees and
used to strengthen the comb and to seal cracks; also called bee glue
Protozoan Small, one-celled animals such as amoebae, ciliates, and flagellates.
Queen bee It is a female bee with a fully developed reproductive organ, and larger
and longer than a worker bee. The queen is the center of the hive. She produces all
of the eggs, the majority of which develop into worker bees, some into male
drones, and a few occasionally become young queens, only when necessary.
12 Glossary of Natural Resources and Environmental Pollution Control
475
flotation clarifier using zero-horizontal velocity design. The effectiveness of
dissolved air flotation depends upon the attachment of bubbles to the suspended
solids and/or oil, which are to be removed from the waste stream. The attraction
between the air bubble and particle is primarily a result of the particle surface
charge and bubble-size distribution. The more uniform the distribution of water
and microbubbles, the shallower the flotation clarifier can be. Generally, the depth
of effective flotation units is between 3 and 9 feet.
Primary sedimentation clarification It is a unit process or unit operation for
removal of mainly total suspended solids (settleable solids and floatable solids)
from screened wastewater using a primary sedimentation clarifier.
Primary sedimentation clarifier It is a tank used to settle mainly total suspended
solids (TSSs) from screened raw wastewater by gravity. The main objectives of a
primary sedimentation clarifier are removal of settleable solids by settling them to
the clarifier bottom, and removal of floatable solids by skimming them from the
clarifier’s wastewater surface. In a rectangular sedimentation clarifier, the wastewater flows from one end to the other and the settled sludge is moved to a hopper
at on end, either by scrapers called “flights” set on parallel chains, or by a single
bottom scraper set on a traveling bridge. Floating materials, such as grease and
oil, are collected by a surface skimmer and then removed from the rectangular
sedimentation clarifier. In a circular sedimentation clarifier, the wastewater usually enters in the middle and flows toward the outside edge. Settled sludge is
pushed to the hopper that is in the middle of the circular clarifier’s tank bottom.
Floating material is removed by a surface skimmer connected to the sludge
collector.
Primary swarm It is the first swarm to leave the parent colony, usually with the old
queen (see secondary swarm).
Primary treatment It is an important wastewater treatment step (either primary
sedimentation clarification or primary flotation clarification mainly for removing
total suspended solids from preliminary treatment effluent) after the preliminary
treatment (i.e., bar screen, comminutor, and grit chamber mainly for removing
large objects from raw wastewater), but before secondary treatment (either
biological treatment or physicochemical treatment mainly for removing dissolved
organic/inorganic pollutants from primary effluent).
Procedure A set of systematic instructions for performing an operation.
Propolis (a) It is called bee glue, which is sap or resinous material that is collected
from trees or plants by bees and used to strengthen the comb and to seal cracks.
(b) They are sap or resinous materials collected from trees or plants by bees and
used to strengthen the comb and to seal cracks; also called bee glue
Protozoan Small, one-celled animals such as amoebae, ciliates, and flagellates.
Queen bee It is a female bee with a fully developed reproductive organ, and larger
and longer than a worker bee. The queen is the center of the hive. She produces all
of the eggs, the majority of which develop into worker bees, some into male
drones, and a few occasionally become young queens, only when necessary.
12 Glossary of Natural Resources and Environmental Pollution Control
475