Aqueous solutions of acetaminophen (ACT) were successfully treated using continuous solar galvanic Fenton (SGF) and galvanic Fenton (GF) processes. Definitive screening design (DSD) was used to verify the influence of several experimental parameters and their interactions, the variables were: the pH, initial ACT concentration, presence or absence of solar irradiation, and H2O2 dose. For the GF system, the maximum removal efficiencies were 64.47% for total organic carbon (TOC) and 49.83% for ACT. For the SGF process, 79.38% TOC and 100% ACT were achieved. The optimal conditions in both systems were 2.5 mM H2O2, and pH 5 at 40 min of retention time. Unlike the analogous EF and PEF processes, the GF and SGF processes do not require external energy.