Bioremediation of Gasoline Engine Exhaust Pollutants using Fixed-bed Biofiltration system

Abstract The exhaust produced by gasoline engines is a significant source of air pollution and a severe hazard to human health and the environment because it releases volatile organic compounds (VOC), nitrogen oxides (NO x ), carbon monoxide (CO) and particulate matter (PM), and polycyclic aromatic hydrocarbons (PAHs). Traditional methods of control like catalytic converters, chemical scrubbers and adsorption systems are sometimes expensive, require a lot of maintenance, and they also produce secondary pollutants, therefore there is a need to find a sustainable solution. This paper describes a hybrid biofiltration system, which uses activated wood-chip biochar in KOH, and a synergistic bacterial consortium of Bacillus subtilis and Pseudomonas aeruginosa to treat the gasoline engine exhaust. The porous biochar structure allows gaseous pollutants to adsorb effectively and at the same time allows the growth of microbes and their biodegradation potential. The proximate analysis, pH, electrical conductivity, and Fourier transform infrared spectrophotometer (FTIR) were used to characterize the biochar. A seven-day closed-loop operation of a laboratory-scale fixed-bed column with gasoline exhaust was conducted. Gas chromatography–mass spectrometry (GC-MS) analyzed the inlet and outlet gases to determine the removal of the pollutants. The developed system of adsorption-biodegradation was able to reduce exhaust pollutants with low operational cost and low levels of secondary waste. These results indicate that biochar-microbe biofiltration has a great potential as a scalable and sustainable technology in gasoline exhaust treatment.