2.1.1 Complete Mix and No Recycle Model
By combining Eqs. (3.1) and (3.4), the following equation is obtained:
S ¼
K s 1 þ bθ
ð
Þ
θ Yk m À b
ð
ÞÀ1
ð3:5Þ
in which S ¼ effluent substrate concentration at steady state. The effect of hydraulic
retention time on the system performance can be illustrated by plotting S vs θ in
Fig. 3.5 which is similar to a diagram presented by Herbert [9].
From a substrate mass balance on the biological reactor, one can derive the
following:
X ¼
Y S 0 À S
ð
Þ
1 þ bθ
ð3:6Þ
in which X ¼ effluent microbial concentration at steady state and S 0 ¼ initial
substrate concentration in wastewater. Assuming negligible amount of biological
sludge leaving the final clarifier and knowing the rate of wastewater flow, the net
sludge production rate can be easily calculated.
Fig. 3.5 Effect of hydraulic retention time on the performance of an activated sludge process
(complete mix model). (Source: US EPA)
3 Biological Processes
89
By combining Eqs. (3.1) and (3.4), the following equation is obtained:
S ¼
K s 1 þ bθ
ð
Þ
θ Yk m À b
ð
ÞÀ1
ð3:5Þ
in which S ¼ effluent substrate concentration at steady state. The effect of hydraulic
retention time on the system performance can be illustrated by plotting S vs θ in
Fig. 3.5 which is similar to a diagram presented by Herbert [9].
From a substrate mass balance on the biological reactor, one can derive the
following:
X ¼
Y S 0 À S
ð
Þ
1 þ bθ
ð3:6Þ
in which X ¼ effluent microbial concentration at steady state and S 0 ¼ initial
substrate concentration in wastewater. Assuming negligible amount of biological
sludge leaving the final clarifier and knowing the rate of wastewater flow, the net
sludge production rate can be easily calculated.
Fig. 3.5 Effect of hydraulic retention time on the performance of an activated sludge process
(complete mix model). (Source: US EPA)
3 Biological Processes
89