In this experiment, the temperature was left unregulated at
ambient temperature, which was about 28 C. The pH value
increased from 7.4 up to the values ranging between 8.33 and 9.14
and thereafter it remained constant. This indicates that pH
adjustment is unnecessary. Tripathi and Allen (1997) also reported
a systematic increase in pH (from 7.5 to 8.5) in the aerobic treatment
of bleached kraft pulp mill effluent. During the course of the
experiment, the DO concentrations in the SBR were found to be in
the range of 1.5e6.4 mg/L.