Wastewater from flue gas desulfurization (FGD) by wet-lime method in a power plant were treated by (i) sedimentation, (ii) coagulation and (iii) Fe-0/H2O2 process. It was proved, that Fe-0/H2O2 process is the most effective in FGD wastewater treatment. As a results COD was decreased from 394 to 204 mg/L (48.3% removal) for 15min process time and Fe-0/H2O2 doses 250/600 mg/L. Fe-0/H2O2 process allows effective heavy metals and boron removal.