Nomenclature
a
Media-specific surface area per unit volume, L
2 /L
3
A
Surface area of the trickling filter, L
2
A c
Biofilm area, L
2
b
Endogenous respiration or decay coefficient, 1/t
C
Constant
C o
DO concentration of the floc surface, M/L
3
C i
DO concentration in the innermost cell of floc, M/L
3
D
Dilution rate, reciprocal of hydraulic retention time, 1/t
D
Diameter of a sphere or cylinder or the thickness of a plane or parallel floc, L
D
Depth of the trickling filter, L
D c
Diffusion coefficient within the biofilm, L
2 /T
D w
Diffusion coefficient of the chemical species through water, L
2 /T
E
Fractional efficiency of BOD removal
E
Electrode potential, millivolts
Eo
Electrode potential when [oxidant] ¼ [reductant], millivolts
E a
Activation energy, cal/mol
E n
Energy consumption, kwh/yr
E T
Efficiency at temperature, T
C
E 1
Percent efficiency of BOD removal of single-stage trickling filter, calculated
by the NRC model, %
E 2
Percent efficiency of BOD removal of second-stage trickling filter, calculated
by the NRC model, %
E 20
Efficiency at 20
C, %
F
Faraday, 23,060 cal/eV
F
Recirculation factor
F 5
Sludge production factor, M solids/M BOD 5
F/M Food-to-microbial mass ratio, mass of substrate applied for unit biomass per
day, 1/t
H
Discharge head, L
J
Flux of substrate into the biofilm, M/L
2 /T
J o
Surface flux of the chemical species, M/T
K
Maximum utilization rate of the rate-limiting substrate, M/T/M
Ka
Adsorption removal constant
km
Maximum rate of specific substrate utilization, 1/t
K
Aconstant
k 1
Reaction rate at temperature T 1
k 2
Reaction rate at temperature T 2
K 20
Cell growth rate or substrate utilization rate at 20
C
K s
Michaelis-Menten constant, or half-velocity coefficient, numerically equal to
the substrate concentration when U ¼ ½ k. M/L
3
K T
Cell growth rate or substrate utilization rate at temperature T
k T
Reaction rate at temperature T
3 Biological Processes
75
a
Media-specific surface area per unit volume, L
2 /L
3
A
Surface area of the trickling filter, L
2
A c
Biofilm area, L
2
b
Endogenous respiration or decay coefficient, 1/t
C
Constant
C o
DO concentration of the floc surface, M/L
3
C i
DO concentration in the innermost cell of floc, M/L
3
D
Dilution rate, reciprocal of hydraulic retention time, 1/t
D
Diameter of a sphere or cylinder or the thickness of a plane or parallel floc, L
D
Depth of the trickling filter, L
D c
Diffusion coefficient within the biofilm, L
2 /T
D w
Diffusion coefficient of the chemical species through water, L
2 /T
E
Fractional efficiency of BOD removal
E
Electrode potential, millivolts
Eo
Electrode potential when [oxidant] ¼ [reductant], millivolts
E a
Activation energy, cal/mol
E n
Energy consumption, kwh/yr
E T
Efficiency at temperature, T
C
E 1
Percent efficiency of BOD removal of single-stage trickling filter, calculated
by the NRC model, %
E 2
Percent efficiency of BOD removal of second-stage trickling filter, calculated
by the NRC model, %
E 20
Efficiency at 20
C, %
F
Faraday, 23,060 cal/eV
F
Recirculation factor
F 5
Sludge production factor, M solids/M BOD 5
F/M Food-to-microbial mass ratio, mass of substrate applied for unit biomass per
day, 1/t
H
Discharge head, L
J
Flux of substrate into the biofilm, M/L
2 /T
J o
Surface flux of the chemical species, M/T
K
Maximum utilization rate of the rate-limiting substrate, M/T/M
Ka
Adsorption removal constant
km
Maximum rate of specific substrate utilization, 1/t
K
Aconstant
k 1
Reaction rate at temperature T 1
k 2
Reaction rate at temperature T 2
K 20
Cell growth rate or substrate utilization rate at 20
C
K s
Michaelis-Menten constant, or half-velocity coefficient, numerically equal to
the substrate concentration when U ¼ ½ k. M/L
3
K T
Cell growth rate or substrate utilization rate at temperature T
k T
Reaction rate at temperature T
3 Biological Processes
75