Shortening the Storage Duration of Food Waste and Adding Ammonia Nitrogen to Food Waste to Increase Hydrogen Yield in Microbial Electrolysis Cells

Acidification occurs during the temporal storage and long-distance transportation of food waste (FW). It can influence FW physicochemical properties and even subsequent treatment and disposal. In this study, microbial electrolysis cells were constructed to evaluate hydrogen (H₂) production and biodegradation behaviors of rice slurry (R) and fermented rice liquid (FR). Carbohydrate, as the main component in R, was more prone to be acidified into acetate and subsequently start H₂ generation. While the dominant component in FR was butyrate, it became a rate-limiting step during anaerobic fermentation, leading to its lower H₂ productivity. Results showed that the H₂ yield of R was 1.48 times higher than that of FR. The microbial community and molecular dynamics simulation revealed that R was readily utilized by g_Aeromonas. This was a more efficient pathway for producing H₂. The additional supply of NH₄⁺-N exerted a more remarkable effect on improving H₂ yield through enriching g_Geobacter and g_Enterococcus.