Innovative approaches for volatile fatty acids recovery from wastes

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The increased organic waste generation and the requirements regulating their ultimate disposal are serious economic and environmental concerns across Canada. Landfilling of organic wastes poses significant risks to the environment and public health. Many municipalities across Canada have already set aggressive waste diversion goals to reduce the environmental footprint of current waste management practices. Thus, there has been growing attention to developing advanced and reliable technologies for bioenergy and value-added resources from waste, which can provide dual benefits of waste diversion and revenue generation. Anaerobic digestion is by far the most widely implemented waste-to-bioenergy technology for converting waste to methane-rich biogas. The biogas produced during anaerobic digestion can be converted into heat and electricity. The process of anaerobic digestion relies on the microbial breakdown of complex organic matter. Organic matter is degraded to various volatile organic acids in the first stage, known as the acidogenic fermentation stage. Then, these organic acids are converted to methane and carbon dioxide in the second stage. In recent years, the possibilities of terminating the process after the fermentation stage and recovering volatile organic acids have received particular attention. These volatile organic acids can be used as a feedstock for various high value-added products, including bioplastics, bioenergy, liquid hydrocarbons, lipids for biodiesel production, electron donors for biological nutrient removal. Currently, volatile organic acids are commercially produced through chemical (carboxylation and oxidation) and biological processes from fossil fuels and pure sugars. The proposed research program focuses on developing a novel acidogenic fermentation system integrating vacuum and hydrothermal technologies. The application of vacuum technology can provide multiple benefits, such as maximizing the process stability, high-grade volatile organic acids with higher yield by continuously removing fermentation products. Moreover, the hydrothermal process provides an excellent opportunity to boost the bioconversion potential of feedstock via solubilization. The advanced knowledge generated from this project will strengthen the continuous efforts of Canada in developing cutting-edge renewable energy and resource harvesting technologies to achieve a low-carbon future.