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. The increasing of g_Flavobacterium accelerated the degradation of starch to generate more H2.