The effect of the electrode materials on phosphate removal efficiency was investigated in a pre-study. One metal material was used as the dissolving anode in a given experiment, whereas another metal was simultaneously used as cathode material. Thus, in these experiments, Al/Fe, Al/stainless steel, Fe/Al, stainless steel/Al, and Fe/stainless steel hybrid electrode combinations were used as anode/cathode pairs at initial pH values of 5 and 9 and initial phosphate concentration of 15 mg/l (instead of 30 mg/l, as in all of the subsequent experiments). Treatment time (t) in each test was 30 min and current density was 130 A/m2 (current of 0.9 A) when Al or Fe was used as the anode material. The corresponding value for stainless steel was 110 A/m2 (current 0.75 A, because 0.9 A could not be reached with this material due to its higher resistance, leading to a higher voltage demand). The optimum treatment time and corresponding phosphate removal percentage for all electrode combinations tested with initial pH values of 5 and 9 are presented in Table 2.