63 / 2023-05-31 17:20:01

Performance of anaerobic digestion from food waste with the addition of nano-Fe2O3

Anaerobic digestion; nano-Fe2O3; Food waste; Methane; Bacterial community.

In order to alleviate the accumulation of volatile fatty acids and the inhibition of ammonia nitrogen in the anaerobic digestion process of food waste, and improve the methane production, nano-Fe₂O₃ was added to the batched mesophilic anaerobic digestion system of food waste. The organic load rate of kitchen waste was 41.25gVS/L, and the VS ratio between inoculants and kitchen waste was 0.5. The results showed that the addition of nano-Fe₂O₃ could promote the maximum methanogenesis rate, shorten the delay time, alleviate the accumulation of VFA, reduce the ammonia nitrogen content of the system, as well as improve the electron transport activity. In terms of methane production, with the increase of the addition amount of 10g/L to 50g/L, the methane production first increased and then decreased. The group with the addition of 30g/L nano-Fe₂O₃ had the highest methane production rate, and the highest methane production up to 364 mLCH₄/g VS, which increased by 7.9% compared with the control, while the kitchen waste added with 50g/L nano-Fe₂O₃ had the lowest methane production, which decreased by 4.5% compared with the control, indicating certain inhibitory effect. Extracellular polymer substance analysis showed that the addition of nano-Fe₂O₃ increased the total sugar content but decreased the soluble protein content. The analysis of microbial community structure showed that the addition of nano-Fe₂O₃ was beneficial to increase the relative abundance of Methanobacterium and Methanolineas. The results of this study will provide reference for the improvement of anaerobic digestion efficiency of high-loading rate of food waste.