Figure 6: The impact of fructose, initial ammonium concentration, and the type of bead pretreatment on the ammonium nitrogen (N-NH4+) concentration in the liquid medium after incubation of the attached PNN consortium for 24 h and 72 h. The initial concentrations of (NH4)2SO4 were 2.5 g/L and 7.5 g/l, respectively. Error bars represent the standard deviation.