Deciphering intricate associations between vigorous development and novel metabolic preferences of partial denitrification/anammox granular consortia within mainstream municipal wastewater

Abstract

There is limited understanding of the granular partial denitrification/anammox (PD/A) microbiota and metabolic hierarchy specific to municipal wastewater treatment, particularly concerning the multi-mechanisms of functional differentiation and granulation tendencies under high-loading shocks. Therefore, this study utilized fragmented mature biofilm as the exclusive inoculum to rapidly establish a granular PD/A system. Following long-term feeding with municipal wastewater, PD/A process reached a total nitrogen removal efficiency of 97.7%, with anammox contributing over 93%. The dominant filamentous bacteria that supported the granular structure underwent significant changes throughout the operational period. Notably, the mature granular PD/A process demonstrated a distinct metabolic preference for recalcitrant, labile, and xenobiotic organics found in municipal wastewater. The biosynthesis of quorum sensing signaling molecules and core cofactors further enhanced the re-development and substrate metabolic adaptations of PD/A granules in real wastewater environments. This research illuminates the micro-ecological succession and metabolic heterogeneity of the granular PD/A process under mainstream loading.