Continuous recovery and enhanced yields of volatile fatty acids from a continually-fed 100 L food waste bioreactor by filtration and electrodialysis.

A novel method to recover VFAs from a continually-fed 100 L food waste bioreactor was developed using industrially applicable methods. The in-situ recovery of VFAs increased production rates from 4 to 35 mg g day by alleviating end-product inhibition and arresting methanogenesis, and electrodialysis was able to concentrate the recovered VFAs to 4000 mg L. There remains considerable scope to increase the production rates and concentrations further, and the VFAs were recovered in a form that made them suitable for use as platform chemicals with minimal refining. This is the first time that continuous VFA recovery from real-world food waste has been reported at this scale with continual feeding, and represents a promising means through which to produce sustainable platform chemicals. Furthermore the production of VFAs arrests methane production in bioreactors, which is a low value product around which there is a growing concern about fugitive emissions contributing to climate change.