Advanced biodegradation process of atrazine in the peroxidase-mediated sequencing batch reactor (SBR) and moving-bed...

The advanced biodegradation process of atrazine was stimulated with hydrogen peroxide (H₂O₂) in a sequencing batch reactor (SBR) under different operational conditions due to in situ generation of H₂O₂-peroxidase. The complete biodegradation and mineralization of 50 mg/L atrazine was achieved in the SBR with a biomass concentration of 328 mg/L stimulated with 10 mM of H₂O₂. The presence of H₂O₂ in the SBR induced the generation of H₂O₂-peroxidase resulted in acceleration of atrazine biodegradation. Adding moving media to the SBR system and converting it to the MSBR considerably improved the rate of atrazine biodegradation and mineralization under H₂O₂ mediation. The highest specific utilization rate of atrazine in the SBR operated at the biomass concentration of 55 mg/L was 19.4 mg/g_biomass.h, while it was 33.5 mg/g_biomass.h in the MSBR operated at the biomass concentration of 37 mg/L. The low ATZ removal along with no peroxidase activity in the bioreactor in absence of H₂O₂ clearly ideated that the biodegradation and mineralization of ATZ was considerably mediated by H₂O₂-peroxidase enzyme. The toxicity of atrazine solution decreased markedly when treated in the MSBR under optimum conditions. Accordingly, the MSBR stimulated with H₂O₂ is an efficient and thus promising process for biodegradation of recalcitrant compounds.