3.3.3. Effect of SLR on TSS removal
The SLR effect on TSS removal efficiency is clearly reflected by
the results shown in Fig. 5. The percentage of TSS removal increased
initially with the increase of SLR and reached the maximum
removal of 98.9% at SLR of 4.6 kg TSS/m3 day. Remarkable TSS
removals (96.2e98.9%) were achieved in this study, which may be
caused by the high sludge settleability in the SBR, as the average
sludge volume index were below 60 mg/L.
Nevertheless, at high SLR (5.7 kg TSS/m3 day), which corresponded
to F/M ratio of 0.32 and OLR of 5.6 kg COD/m3 day, the
settling of the sludge was poor. At such high SLR, influent colloidal
particles are not effectively retained in the activated sludge floc.
This phenomenon was reported by Chin et al. (1987) in the treatment
of PORE. It was revealed that the optimum SLR falls in the
range of 2.5e4.6 kg TSS/m3 day which is capable of removing more
than 98% TSS.