Phenol biodegradation using bio-filter tower packed column with immobilized bacterial consortium: a batch test study

The effluents from pulp and paper manufacturing industries contain high concentrations of phenol, which when discharged directly into surface water streams, increases the biological oxygen demand (BOD) and chemical oxygen demand (COD). In this study, two dominant bacteria SP-4 and SP-8 were isolated from the effluent emanating with a pulp and paper industry. The selected phenol-degrading isolates were identified as Staphylococcus sp. and Staphylococcus sciuri respectively by using nucleotide sequence alignment and phylogenetic analysis of 16 S rRNA regions of the genome. The two isolates used for the biodegradation process effectively degraded phenol concentration of pulp and paper industry effluent upto 1600 and 1800 mg/L resepctively. The individual isolates and consortium were immobilized using activated carbon, wood dust, and coal ash. Additionally, the effluent was treated using a bio-filter tower packed column immobilized with bacterial cells at a constant flow rate of 5 mL/min. The present study showed that the developed immobilized microbial consortium can effectively degrade 99% of the phenol present in pulp and paper industry effluents, resulting in a significant reduction in BOD and COD of the system. This study can be well implemented on real-scale systems as the bio-filter towers packed with immobilized bacterial consortium can effectively treat phenol concentrations up to 1800 mg/L. The study can be implemented for bioremediation processes in phenolic wastewater-contaminated sites.