Effect of H₂O₂ concentration as electron Acceptor on bioregeneration of activated carbon contaminated with a benzene-toluene mixture

Abstract

Granular Activated carbon (AC) is commonly used for cleaning water contaminated with Benzene and toluene (BT). Regeneration is needed to extend the lifetime of GAC. This study examines the effect of H2O2 concentration as an electron acceptor for GAC bioregeneration by the consortium of Pseudomonas aeruginosa, Pseudomonas fluorescens, Aeromonas hydrophila, Bacillus coagulants, and Bacillus substilis in a fixed-bed bioreactor. Enrichment was carried out for adaptation to benzene and toluene. The enriched consortium was injected into a bioreactor column containing GAC saturated with benzene and toluene. The H2O2 concentration was varied 10 mg/l, 30 mg/l, 40 mg/l, and 50 mg/l. The contaminant mixture was continuously added with Lockhead and Chase (LC) and H2O2 at a flow rate of 18.2 ml/minute and 1 ml/minute, respectively. The outlet sample was analyzed using a Gas Chromatograph-Flame Ionization Detector (GC FID). The consortium regenerated the GAC by biodegradation of adsorbed benzene toluene. Initial inoculation of enrichment was 3.5 x 105 CFU/ml. The final stationary phase was at 120 hours with 1.37 x 1011 CFU/ml. The optimum biodegradation process was at a concentration of 30 mg/l H2O2 with a concentration of benzene and toluene outlet column II of 25 ppm and 40.5 ppm, respectively.