Biodegradation of anthracene and pyrene in a laboratory-scale biobarrier

The ability of a developed enrichment culture to degrade two PAHs, anthracene and pyrene, was investigated at 10degreesC. The overall biodegradation of 2 mg/L PAHs with free cell suspension was over 97%, where 19% anthracene and 62% pyrene were mineralized to carbon dioxide and water. At the initial PAH concentration of 20 mg/L, over 96% PAHs were degraded, where only 9% anthracene and 5% pyrene were mineralized. A laboratory-scale biobarrier, inoculated with the enrichment culture, was evaluated for the removal of PAHs from contaminated water. High removal efficiency of PAHs was maintained in the biobarrier as well as in a control system which was not inoculated with the PAH-degrading consortium. After stabilization of the experimental system, between 94% and 100% removal of PAHs was obtained in both systems. PAH elimination rates ranged from 0.15 to 3.21 mg/L.d for influent PAH concentrations of 0.93 to 6.21 mg/L. The high removal efficiencies obtained in the biobarrier and in the control system were primarily due to the superior sorption capacity of the packing material. Independent mineralization experiments, using the microbial culture withdrawn from the biobarrier, confirmed the biological degradation of contaminants in the biobarrier.