Fig. 3

Boxplots of the retention ratios during steady-state operation (weeks 7–12) in R1 (a), R2 (b) and R3 (c). Values significantly different from 1 are marked with asterisk (p values are shown above the plots)
Boxplots of the retention ratios during steady-state operation (weeks 7–12) in R1 (a), R2 (b) and R3 (c). Values significantly different from 1 are marked with asterisk (p values are shown above the plots)