Treatment of Port Harcourt Refinery Effluent by a Bacterial Consortium Immobilized on Agro-based Bio Carriers

Discharge of poorly treated refinery wastewater has always been a major environmental challenge. Bacterial immobilization is key to the maintenance of biomass on a contaminated site. In this study, a mixed culture of three bacterial isolates from oil-polluted water: Pseudomonas aeruginosa (MN294989), Bacillus tequilensis (MN294990) and Micrococcus sp. immobilized on Groundnut Shell (GS), Melon Husk (MH) and Sugarcane Bagasse (SB) were employed in the bioremediation of Port Harcourt refinery wastewater. Surface area and pore size distribution of the agro-based bio carriers were suitable for bacteria adhesion. The bacterial isolates were screened for phenol, naphthalene and hydrocarbon utilization. Scanning Electron Microscopy (SEM) was used to ascertain the immobilization of the consortium on the agro-base carriers. A 15-days laboratory-scale treatment of refinery raw wastewater was compared in the immobilised and immobilized consortium. The agro-based residue immobilized consortium enhanced the reduction in BOD5, COD, oil and grease, phenol by 7%, 9%, 30% and 5% respectively compared to the free form of the consortium. This study underscores the role of immobilization in maintaining high bacterial biomass on contaminated site and possible improvement in bioremediation of refinery wastewater.