Effect of calcium addition on the formation and maintenance of aerobic granular sludge (AGS) in simultaneous fill/draw mode sequencing batch reactors (SBRs).

This work investigated the effect of Ca (100 mg L) addition on the formation and maintenance of aerobic granular sludge in a simultaneous fill/draw mode sequencing batch reactor (SBR), operated with a low liquid upflow velocity (0.92 m h), in order to verify if Ca presence compensates the low selection pressure imposed. Additionally, carbon and nutrients removals, granules characteristics and microbial community were evaluated.