Fenton Treatment of Filter Backwash Water for Recycling in DWTP

Drinking water treatment plants (DWTPs) generate residues, such as filter backwash water (FBW), that can harm the aquatic environments if discharged into water sources. In this sense, FBW recycling has gained attention. Nevertheless, it requires treatment to maintain operational efficiency and water quality in the DWTP. This work analyzed the main variables interfering with Fenton treatment of FBW from a full-scale DWTP aiming at removing turbidity and microorganisms. Bench-scale tests successfully inactivated 100% of Escherichia coli. Desired removal of other parameters (99.1% of turbidity, 99.9% of color, and achieving a 2.5 log₁₀ reduction of aerobic endospores) occurred during the sedimentation stage. There was a strong influence of the pH sample and the concentration of added hydrogen peroxide on the removal of microorganisms. This study represents an initial stage that should be continued to enable the removal of resistant microorganisms through oxidation by the Fenton reaction in FBW treatment.