wasted. An intermediate aeration step for stabilization (much less than 40 min)
may be needed to guard against carryover of carbonaceous materials. The denitrification reactor may be covered but not air-tight to assure anaerobic conditions.
4. Denitrification followed by membrane clarification: Same as “denitrification
followed by flotation clarification” except that the flotation clarification is
replaced by a membrane filtration reactor.
5. Sequencing batch flotation (SBF): A sequencing batch process (either biological
or physicochemical) involving the use of separate batch process steps in sequence
of filling water/wastewater, reacting with chemicals or biomass, floating lightweight insoluble flocs and/or biomass, discharging treated effluent, and wasting
floated insoluble scums for water or wastewater treatment is also called sequencing batch flotation (SBF) process (US Patent 5354458).
6. Biological sequencing batch reactor (SBR): A biological SBR system performs
all the necessary functions of carbonaceous and nutrient removals in a single tank
with variable water levels and timed aerobic aeration or anoxic mixing. This SBR
system requires a minimum of three tanks and advanced automation equipment to
control the cycle times and phases. The SBR control systems allow the operation
to be configured to operate as almost any other suspended-growth biological
reactor by adjusting the cycle phases between fill phase, react phase (either
aerobic aeration or anoxic mixing), separation phase (either sedimentation or
flotation), and decant phase. The biological SBR system involving the use of
flotation in the separation phase is invented by Dr. Lawrence K. Wang,
Dr. Lubomyr Kurylko, and Dr. Mu-Hao Sung Wang in 1994 (US Patent
5354458).
Glossary [158–166]
Activated sludge process: It is a continuous flow, biological treatment process
characterized by a suspension of aerobic microorganisms, maintained in a relatively homogeneous state by the mixing and turbulence induced by aeration. The
microorganisms are used to oxidize soluble and colloidal organics to carbon
dioxide and water in the presence of molecular oxygen. The process is generally,
but not always, preceded by primary clarification (either primary sedimentation
clarification or primary flotation clarification). The mixture of microorganisms
and wastewater formed in the aeration basins, called mixed liquor (ML), is
transferred to secondary clarification (either secondary sedimentation clarification
or secondary flotation clarification) for liquid-solid separation. The major portion
of the microorganisms separated from the secondary clarifiers (secondary sedimentation clarifiers or secondary flotation clarifiers) is recycled to the aeration
basins to be mixed with incoming wastewater, while the excess, which constitutes
the waste activated sludge (WAS), is sent to the sludge handling facilities. The
rate and concentration of the returned activated sludge (RAS) returned to the
aeration basins determines the mixed liquor suspended solids (MLSS) level
3 Biological Processes
139
may be needed to guard against carryover of carbonaceous materials. The denitrification reactor may be covered but not air-tight to assure anaerobic conditions.
4. Denitrification followed by membrane clarification: Same as “denitrification
followed by flotation clarification” except that the flotation clarification is
replaced by a membrane filtration reactor.
5. Sequencing batch flotation (SBF): A sequencing batch process (either biological
or physicochemical) involving the use of separate batch process steps in sequence
of filling water/wastewater, reacting with chemicals or biomass, floating lightweight insoluble flocs and/or biomass, discharging treated effluent, and wasting
floated insoluble scums for water or wastewater treatment is also called sequencing batch flotation (SBF) process (US Patent 5354458).
6. Biological sequencing batch reactor (SBR): A biological SBR system performs
all the necessary functions of carbonaceous and nutrient removals in a single tank
with variable water levels and timed aerobic aeration or anoxic mixing. This SBR
system requires a minimum of three tanks and advanced automation equipment to
control the cycle times and phases. The SBR control systems allow the operation
to be configured to operate as almost any other suspended-growth biological
reactor by adjusting the cycle phases between fill phase, react phase (either
aerobic aeration or anoxic mixing), separation phase (either sedimentation or
flotation), and decant phase. The biological SBR system involving the use of
flotation in the separation phase is invented by Dr. Lawrence K. Wang,
Dr. Lubomyr Kurylko, and Dr. Mu-Hao Sung Wang in 1994 (US Patent
5354458).
Glossary [158–166]
Activated sludge process: It is a continuous flow, biological treatment process
characterized by a suspension of aerobic microorganisms, maintained in a relatively homogeneous state by the mixing and turbulence induced by aeration. The
microorganisms are used to oxidize soluble and colloidal organics to carbon
dioxide and water in the presence of molecular oxygen. The process is generally,
but not always, preceded by primary clarification (either primary sedimentation
clarification or primary flotation clarification). The mixture of microorganisms
and wastewater formed in the aeration basins, called mixed liquor (ML), is
transferred to secondary clarification (either secondary sedimentation clarification
or secondary flotation clarification) for liquid-solid separation. The major portion
of the microorganisms separated from the secondary clarifiers (secondary sedimentation clarifiers or secondary flotation clarifiers) is recycled to the aeration
basins to be mixed with incoming wastewater, while the excess, which constitutes
the waste activated sludge (WAS), is sent to the sludge handling facilities. The
rate and concentration of the returned activated sludge (RAS) returned to the
aeration basins determines the mixed liquor suspended solids (MLSS) level
3 Biological Processes
139