Enhanced aerobic granulation by applying the low-intensity direct current electric field via reactive iron anode

A novel granulation strategy by applying the low-intensity direct current (DC) electric field via reactive iron anode into the aerobic granular sludge (AGS) system was systematically investigated in this study. Three identical sequencing batch reactors (SBRs, namely R1, R2, and R3) were operated for 100 days. Comparatively, the R1 and R3 were continuously subjected to the 1.0 V DC electric field via a reactive Fe anode and an inert Ti-Ir/Rh anode, respectively, while the R2 without DC exposure. The results showed that the sludge granulation processes were accelerated in order as follows: R2