Simultaneous nitrogen and phosphorus removal was enhanced by altering the
influent chemical oxygen demand/nitrogen (COD/N) ratio. At COD/N ratio of 9, total nitrogen (TN) and
total phosphorus (TP) removal efficiencies were up to 89.8% and 77.5%, respectively. Three-dimensional
excitation–emission matrix (3D-EEM) spectroscopy showed that the chemical compositions of sludge EPS
were changed during granulation process. The results could provide useful information to promote nitrogen and phosphorus removal using aerobic granular sludge technology.