ENHANCEMENT OF GRANULATION AND START-UP IN THE ANAEROBIC SEQUENCING BATCH REACTOR

The phenomenon of granulation was studied in anaerobic sequencing batc h reactors (ASBRs) treating a synthetic sucrose wastewater. The object ive was to study methods of minimizing the time typically required for start-up of anaerobic processes, such as the ASBR. Specifically, it w as hypothesized that development of a granular biomass soon after init ial start-up of the ASBR would significantly decrease the overall time required to achieve given organic and hydraulic loading rates. Labora tory-scale ASBRs were seeded with anaerobically digested municipal bio solids and operated until granulation was observed or for a period of 5 months without granule development, whichever occurred first. Granul e development was measured by determination of the aver age particle d iameter of a representative sample of biosolids from the ASBRs. Granul ation enhancements were added to the ASBRs to initiate early granule d evelopment and to aid in start-up. Enhancements included powdered acti vated carbon, granular activated carbon,silica sand, garnet, polymers, and ferric chloride. The cationic polymer had the most beneficial eff ects on granulation enhancement, reducing the time required to form gr anules by approximately 75% compared to an unenhanced control ASBR.