Microbial community evolution and individual-based model validation of biofilms in single-stage partial nitrification/anammox system.

[Display omitted] • Biofilms grown at different polyurethane carrier depths were layered. • Three distinct stages of biofilm development were studied. • Measurements and modeling were performed at various carrier depths. • AOB, AnAOB, and denitrifiers were mostly in the outer, middle, and inner layers. In this study, matrix degradation, microbial community development, and distribution using an individual-based model during biofilm formation on carriers at varying depths within a single-stage partial nitrification/anammox system were simulated. The findings from the application of individual-based model fitting, fluorescence in situ hybridization, and high-throughput sequencing reveal the presence of aerobic bacteria, specifically ammonia-oxidizing bacteria, as discrete particles within the outer layer of the carrier. Facultative anaerobic bacteria exemplified by anaerobic ammonia-oxidizing bacteria, are observed as aggregates within the middle layer. Conversely, anaerobic bacteria, represented by denitrifiers, are enveloped by extracellular polymeric substances within the inner layer. The present study extends the application of individual-based model to the formation of polyurethane-supported biofilms and presents valuable avenues for the design and advancement of pragmatic engineering carriers. [ABSTRACT FROM AUTHOR]