3.3.1. Effect of HRT
The influence of HRT on TMP was observed to be similar for all
the SAnMBRs. That is, when HRT was decreased, TMP
increased faster to the value of 30 kPa, a point when chemical
cleaning was required. For example, at an HRT of 12 h, the
membrane fouling happened within around 90 d, which was
shortened to two months when the HRT was reduced to 8 h
(Fig. 4a and c). This phenomenon was due firstly, to the
increase of biomass concentration resulted from an increase
in OLR as the HRT was reduced, which greatly enhanced
membrane fouling rate; Secondly, membrane fouling was
significantly affected by SMP compositions.