Pathogen Removal in Aerobic Granular Sludge Treatment Systems

This book describes pathogen removal processes in aerobic granular  sludge (AGS) wastewater treatment systems. Faecal indicators (E. coli,  Enterococci, coliforms and bacteriophages) were tracked in full-scale  AGS facilities and compared to parallel activated sludge (CAS) systems.  AGS showed similar removals as the more complex CAS configurations.  Removal mechanisms investigated in laboratory-scale reactors showed that  the AGS morphology contributes to the removal processes. By tracking E.  coli and MS2, it was observed that organisms not attached to the  granules are predated by protozoa during aeration. 18S RNA gene analyses  confirmed the occurrence of bacterivorous organisms (e.g., Epistylis,  Vorticella, Rhogostoma) in the system. Particulate material in the  feeding stimulated their development, and a protozoa bloom arose when  co-treating with (synthetic) faecal sludge (4 % v/v). An overview of the  diverse eukaryotic community in laboratory reactors and real-life  applications is also provided. The microbial diversity of the influent  was different compared to AGS and CAS sludge samples. However, no clear  differences were found between them on species level. This study  contributes to a better understanding of the mechanisms behind pathogen  removals in AGS systems.