Laboratory studies on enhancement of granulation in the anaerobic sequencing batch reactor

The phenomenon of granulation was studied in anaerobic sequencing batch reactors (ASBRs) treating a synthetic sucrose wastewater. The objective was to study methods of minimizing the time typically required for start-up of high rate anaerobic processes, such as the ASBR, when utilizing biomass from typical anaerobic digesters. More specifically, the goal was to develop granular biomass soon after initial start-up of the ASBR in order to decrease the overall time required to achieve high rate anaerobic treatment. Laboratory-scale ASBRs were seeded with anaerobically digested municipal biosolids and operated until granulation was observed. Granule development was measured by determination of the average particle diameter of a representative sample of biosolids from the ASBRs. Cationic polymer was added to the test ASBR to enhance rapid granule development and to aid in start-up. Cationic polymer addition reduced the time required to form granules by approximately 75% compared to an un-enhanced control ASBR.