Figure 7.

Effects of pH and HRT variation on the algae-bacteria cultivation in terms of the following: algal biomass productivity (A: HRT variation, B: pH variation), apparent TAN removal rate (C: HRT variation, D: pH variation), orthophosphate removal rate (E: HRT variation, F: pH variation), and TSS percentage fractionation (G: HRT variation, H: pH variation). X_S is the particulate slowly biodegradable organic matter, while X_I is the particulate inert organic matter. Simulations at different HRTs were run at a pH set point of 7.5 (scenarios S1, S3–S6, S11), while simulations at different pH set points were run with HRT = 5 d (scenarios S4, S7–S11).