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Application of Anaerobic Membrane Bioreactor 421

10.4.3.1.1 The Effect of OLR on COD Removal Efficiency
As the concentration of COD in the feed and permeate varied on daily basis,
the average COD removal efficiency was calculated for the AnMBR con-
sidering the average COD concentration in feed and permeate during each
period of OLR. The average COD removal efficiency as a function of OLR
is shown in Figure 10.11. The COD removal efficiency of the AnMBR was
3
97.67% for an OLR of 0.62 kg COD/m /day and corresponding HRT of
15 h. The COD removal efficiency of the AnMBR was reduced to 97.14%
3
and 95.58% for an OLR of 0.77 and 0.92 kg COD/m /day, respectively.
3
Within the OLR range from 0.62 to 0.77 kg COD/m /day, COD removal
efficiency did not vary to a considerable extent and was relatively indepen-
dent of the OLR. The COD removal efficiency of the AnMBR was 93.77%
3
for an OLR of 1.32 kg COD/m /day with a corresponding HRT of 7 h.
The permeate sample was continuously monitored for the concentration
of BOD 5 . Average feed concentration of BOD 5 maintained during this phase
of study was 247 mg/L. The average concentration of BOD 5 in the permeate
samples was less than 5 mg/L during the experiments for 15 and 12 h HRT.
The average concentrations of BOD 5 in permeates were 7 and 11 mg/L

98

97

96
% COD removal 95

94

93

92

91
0.62 0.77 0.92 1.32
3
OLR (kg COD/m /day)
% COD removal
Figure 10.11 COD removal efficiency as a function of OLR.