Enhancing dark fermentative biohydrogen and VFA production via ozone pre-treatment

This study investigates the effects of ozone pre-treatment on two types of organic wastes: secondary sludge (SS) and wine vinasse (WV). Ozone pre-treatment of SS, a semi-solid waste, significantly increased the Dissolved Organic Carbon (DOC) and Total Volatile Fatty Acids (TVFAs) through hydrolysis. Conversely, ozone pre-treatment of WV, a liquid organic waste, reduced the availability of soluble biodegradable substrates and decreased the concentration of carboxylic acids with carbon chain length higher than 4. Based on these findings, the impact of ozonation on subsequent dark fermentation Biochemical Hydrogen Potential (BHP) was assessed for SS. The results, modeled for an ozone dose of 0.018 g O₃/g TS, indicated a substantial enhancement in bio-hydrogen production by approximately 160% and VFA production by about 350%. In conclusion, ozone pre-treatment shows significant potential to enhance dark fermentation of particulate substrates like secondary sludge, supporting sustainable waste valorization strategies.