show Abstracthide AbstractAn lab-scale EBPR reactor was operated for granular sludge by reducing the sludge settling time. Large aggregates containing diverse microbial communities were sequenced to determine their differences between communities from flocular sludge. Two reactors were run in 2008 that contained identical carbon and phosphorus concentrations but other operational conditions were altered so that one reactor produced small bacterial aggregates called flocs, and the second reactor produced large bacterial aggregates called granules.