Initial pH of the SW at different carbon concentrations was
adjusted to 7 before being added to the flasks. The pH showed an
increasing trend with time for all the carbon concentrations, which
might be due to the utilization of VFA by bacteria (Fig. 3). At 120 h,
SW at 20 g/l concentration showed highest increment in pH
(7–9.38), followed by 30 g/l (7–9.32), 15 g/l (7–8.98) and 10 g/l
(7–8.32). SW at 50 g/l (7–7.89), and 60 g/l (7–7.21) concentrations
showed little decrement in pH due to lower utilization of VFA by
bacteria. Changes in the pH values were correlated well with the
TOC and VFA removal pattern.