The Operation of Plants Treating Mixed Industrial Wastes
551
Readily removable are those, for which maximum value of substrate oxidation occurs at
S = °°, where:
R
= Rmax
Removable, but toxic are those substrates, for which maximum value, R = Rt, occurs
atS = S t = V K m I .
In the case of non-degradable resp. poisonous substrates,
R < 1.
Substrates — especially poisonous ones — exert an influence not only on substrate —, but
also on endogenous metabolism, as expressed in Equ. 5.
Interpretation of the constants in the R(S) functions
The values of Rmax
ar
*d Rt> respectively, can be easily measured and are a numerical
measure of biological treatability of a waste. Some values for various wastes are included
in Table 2.
The interpretation of the constant K m is well-known; I is the inhibition constant for
substrate metabolism and I e is the one for endogenous metabolism. For phenol and
numerous poisonous bacterial substrates, I < I e , because, generally, substrate metabolism
is more sensitive to poisoning than endogenous metabolism. I e is analogous to the TL m
value in toxicology, it gives the concentration at which metabolism drops to half of the
control value (See Fig. 1). I e can be measured directly, I calculated from the known K m
and measured St values (See Fig. 2).
Note that time factor does not appear in any of R(S) functions, as it would be the case
when the constants are derived from cumulative oxygen consumption graphs (i.e.
Warburg curves). In 0 2 consumption time functions, the constants often cannot be
brought to an explicit form, which makes it hard to employ them to kinetics assessment
in waste treatment practice [6, 7, 8].
Soluble substrate leak-through
In the case of a well-operated biological purification plant, the concentration regime of
dissolved substrate is
0 < S < K m ,
where
dR_
dS
^ - 1
r o
L
(6)
(see also Fig. 1)
If the plant is overloaded, effluent substrate will rise:
where
AC —
U
K m < S < <
dR
dS
(7)
551
Readily removable are those, for which maximum value of substrate oxidation occurs at
S = °°, where:
R
= Rmax
Removable, but toxic are those substrates, for which maximum value, R = Rt, occurs
atS = S t = V K m I .
In the case of non-degradable resp. poisonous substrates,
R < 1.
Substrates — especially poisonous ones — exert an influence not only on substrate —, but
also on endogenous metabolism, as expressed in Equ. 5.
Interpretation of the constants in the R(S) functions
The values of Rmax
ar
*d Rt> respectively, can be easily measured and are a numerical
measure of biological treatability of a waste. Some values for various wastes are included
in Table 2.
The interpretation of the constant K m is well-known; I is the inhibition constant for
substrate metabolism and I e is the one for endogenous metabolism. For phenol and
numerous poisonous bacterial substrates, I < I e , because, generally, substrate metabolism
is more sensitive to poisoning than endogenous metabolism. I e is analogous to the TL m
value in toxicology, it gives the concentration at which metabolism drops to half of the
control value (See Fig. 1). I e can be measured directly, I calculated from the known K m
and measured St values (See Fig. 2).
Note that time factor does not appear in any of R(S) functions, as it would be the case
when the constants are derived from cumulative oxygen consumption graphs (i.e.
Warburg curves). In 0 2 consumption time functions, the constants often cannot be
brought to an explicit form, which makes it hard to employ them to kinetics assessment
in waste treatment practice [6, 7, 8].
Soluble substrate leak-through
In the case of a well-operated biological purification plant, the concentration regime of
dissolved substrate is
0 < S < K m ,
where
dR_
dS
^ - 1
r o
L
(6)
(see also Fig. 1)
If the plant is overloaded, effluent substrate will rise:
where
AC —
U
K m < S < <
dR
dS
(7)