Suspended sludge and biofilms in PNA-IFAS reactors for autotrophic nitrogen removal

This study aims to develop a new seeding and start-up strategy to assist the start-up and improve the nitrogen removal of a PNA-IFAS reactor. Two bioreactors, including a reactor that was started conventionally with the pre-acclimated suspended PNA sludge and bare biocarriers (PA-S) and a reactor that used the new seeding method with anammox biofilms pre-acclimated on biocarriers in a packed bed biofilm reactor and ammonia-oxidizing bacteria (AOB) sludge in the suspension (PA-B), were used in the experiments.