Figure 6.

Bacterial cell density (a) and species richness (b) expressed, respectively, as log cells and species diversity cm⁻² membrane after adhesion and biofilm formation of activated sludge on PE, PSF, and PVDF membranes. Bacterial cell densities were enumerated using 16S rRNA qPCR and log transformed before analysis. The richness was calculated by the sum of the number of peaks (OTU's) within each ARISA electropherogram. Results for the adhesion on the PE membrane are not available due to repeated unsuccessful PCR amplification (^†). Error bars represent standard deviation (n = 3). Adhesion = 1 h incubation in the lab-scale MBR, Ringer = 1 h incubation in the lab-scale MBR followed by 24 h biofilm in Ringer's solution, biofilm = 24 h incubation in the lab-scale MBR, and * = significantly different.