Review of industrial bioethanol production with a focus on volatile fermentation byproducts

The recent surge in biofuel production, particularly bioethanol production, marks a major stride toward renewable and sustainable fuel solutions. Bioethanol, derived from biomass, is mainly produced from starch- or sugar-rich crops, such as corn, wheat, and sugarcane, particularly in the United States and Brazil. However, the industrial production of bioethanol poses environmental challenges, notably the emission of volatile organic compounds (VOCs) from manufacturing facilities. This review explores VOC emissions associated with fermentation for ethanol production, with the aim of elucidating the formation mechanisms, prevention, monitoring, and treatment of volatile fermentation byproducts. Regulatory mandates require ethanol plants to mitigate the annual mass of hazardous air pollutant (HAP) emissions, which are traditionally managed using carbon dioxide scrubbers and regenerative thermal oxidizers. However, these conventional techniques require substantial amounts of water and natural gas. This review analyzes conventional and novel VOC removal methods in ethanol plants, offering comprehensive insights into this process. Additionally, the paper evaluates various Nebraska ethanol plants, comparing VOC and HAP emissions between large and small facilities, both with and without continuous emissions monitoring systems (CEMS). Results indicate smaller facilities employing CEMS are able to operate their air emissions systems more efficiently. • Bioethanol from crops (i.e. corn & sugarcane) is a sustainable fuel solution. • VOC emissions from ethanol plants pose environmental and health concerns. • Acetaldehyde is the primary hazardous air pollutant in ethanol fermentation. • Small ethanol plants with CEMS achieve improved air emissions efficiency. • CEMS enable cost-effective chemical and water use in VOC treatment systems.