title: sludge
design: Biofilm samples were collected at the initial inoculation (day 0) and early colonization phase (day 7), as well as under different aeration pressures in Stage C (0.1, 0.05, and 0.02 MPa). Total genomic DNA was isolated from collected biomass using the E.Z.N.A. Soil DNA Kit (Omega Bio-tek, USA) following the manufacturer's protocol. DNA purity and concentration were assessed through 1.0% agarose gel electrophoresis and NanoDrop 2000 spectrophotometry (Thermo Scientific, USA). Amplification of the bacterial 16S rRNA gene V3-V4 hypervariable region employed primer sets of 338F (5'-ACTCCTACGGGAGGCAGCAG-3') and 806R (5'-GGACTACHVGGGTWTCTAAT-3') [32] on a T100 Thermal Cycler (BIO-RAD, USA). Raw sequencing data are accessible in the NCBI SRA database under accession number of SRP****. Data analysis was performed using the Majorbio Cloud [33, 34].