Characterization of ammonia oxidizing bacteria in an activated sludge plant using a fluorescent in situ hybridization method

The spatial arrangement of functionally important ammonia oxidizing bacteria (AOB) in activated sludge flocs is largely unknown and activated sludge flocs are regarded as heterogeneous agglomerations of bacterial communities. This study aimed to determine both the location of AOB microcolonies within flocs and the size variation of these microcolonies based on their location.