Plots 5 (c) and (d) show the interacting effects between the initial BTEX and NH4Cl and
NaH2PO4 concentrations, respectively. The dimensional plots show that the differences between low and high concentrations of NH4Cl and NaH2PO4 were small at all ranges of BTEX concentrations
although the degradation efficiencies were quite different at low and high concentrations of BTEX, which suggests that the impact of BTEX concentration was larger than those of NH4Cl and NaH2PO4
concentrations.