The impact of the advanced H2O2/O3 oxidation process on improving the efficiency of biological treatment of wastewater from a car wash

Abstract

Advanced oxidation processes before biological wastewater treatment processes are used to increase the amount of the biodegradable fraction, easily assimilated by microorganisms. The article analyzes the impact of the H₂O₂/O₃ process used in sequence with the biological treatment process in moving bed bioreactors on increasing the efficiency of car wash wastewater treatment. In the H₂O₂/O₃ process, 3 doses of hydrogen peroxide were used (27.5 mg/dm₃, 82.5 mg/dm₃, 137.5 mg/dm₃) and a constant dose of ozone (100 mg/dm3). After the oxidation process, the wastewater was directed to reactors for biological wastewater treatment. The operating time of the bioreactors was 24 hours, and samples were taken after 2 h, 6 h and 24 h. A number of physico-chemical parameters were determined in the sewage, such as COD, BOD₅, total nitrogen and total phosphorus, color and turbidity, pH and conductivity. The research showed that wastewater oxidation using the lowest analyzed dose of H₂O₂ in the analyzed advanced oxidation process (27.5 mg H₂O₂/dm³, 100 mgO₃/dm³) contributed to increasing the efficiency of removal of organic matter, nitrogen and total phosphorus in the biological treatment process.