A bacterial consortium for treatment of Fat, Oil, and Grease (FOGs) in wastewater treatment plants

Abstract

Fats, oils and greases (FOG), CER 190809, in wastewater create problems including the production of foul odours, the blockage of sewer lines and interference with the proper operation of sewage treatment works. Removal of FOG is thus critically important to ensure that wastewater is disposed of efficiently and economically. In this study, 232 bacterial strains were isolated and screened for the ability to degrade lipids from a specialized treatment plant, where a enhanced FOG degradation activity had been detected. Enrichment cultures on oily substrates, followed by isolation on selective media for lipase producing bacteria, and enzymatic methods were used to screen lipolytic microorganisms. In a second step, the lipolytic bacteria were analyzed using a colorimetric assay to detect the transesterification activity of para-nitrophenyl-palmitate. Four best performing lipid-degrading bacteria were identified by 16SrDNA sequencing, and investigated for application in treatment of lipids-contaminated wastewater, in Sequencing Batch Reactor (SBR) pilot plant. The FOG biodegradation efficiency was evaluated after 10 days using the gravimetric method for quantitative determination of total oily substances. The bacterial strains were Gram negative affiliated to Serratia, Aeromonas, Pedobacter genera. The Bacterial consortium was able to degrade 76% of FOG in 10 days treatment. The strains are be of great interest at industrial scale to increase the removal of FOG in wastewater treatment plants, and directly in the waste storage tanks at catering establishments, to reduce the polluting load before transfer to the disposal plan. The process of bioaugmentation using the FOG degrading consortium was recently patented (n°812021000056699)