Sidestream Treatment of Anaerobically Digested Sludge Centrate Using Activated Sludge and Aerobic Granular Sludge Sequencing Batch Reactors

In this research, two 1.5-L activated sludge (AS)-sequencing batch reactors (SBRs) were seeded with return activated sludge (RAS) and operated at a hydraulic retention time (HRT) of 72-hr to enable nitrification of centrate with an ammonia-nitrogen (NH -N)3concentration of 572 ± 28 mg/L. Secondly, three 1.2-L aerobic granular sludge (AGS)-SBRs were each operated at a 12-hr followed by an 8-hr HRT to cultivate aerobic granules from RAS. The AGS-SBRs were fed with a combination of diluted and synthetic centrate to perform nitrification only and simultaneous nitrification-denitrification (SND). NH3-N removal efficiencies in the AS-SBR operated with supplemental alkalinity was 100 ± 0% (26 to 93 day), while the control AS-SBR that operated th nd without supplemental alkalinity achieved 61 ± 2% (18 to 52 day) due to incomplete nitrification. The AGS-SBRs fed with diluted centrate, synthetic centrate, and diluted centrate with supplemental organic carbon displayed average NH -N 3emoval efficiencies of 93 ± 19%, 94 ± 16%, and 92 ± 9%, respectively.