Effects of Iron-Loaded Biochar on the Anaerobic Co-Digestion of Food Waste and Sewage Sludge and Elucidating the Mechanism Thereof

Wenxu Lu, Guanyong Deng, Xiaoge Cheng and Wan Wang
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Wenxu Lu: School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China
Guanyong Deng: School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China
Xiaoge Cheng: School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China
Wan Wang: School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China

Sustainability, 2022, vol. 14, issue 15, 1-11

Abstract: The inhibition of volatile fatty acid (VFA) production is an important factor affecting biogas (methane) production in the anaerobic co-digestion systems comprising food waste and sewage sludge. In this study, batch experiments were conducted at medium temperature (36 ± 0.5 °C), during which the biogas production index and material–liquid characteristic parameters of the anaerobic digestion systems containing different concentrations of iron-loaded biochar (Fe-BC) were monitored. The cumulative biogas production data were analyzed using a modified Gompertz kinetic model to determine the effect of the Fe-BC on biogas production in the anaerobic co-digestion system. Studies have shown that addition of Fe-BC does not significantly influence the hydrolysis and acidification stages of anaerobic co-digestion, but does have a significant effect on promoting methanogenesis by alleviating the accumulation of VFAs and improving both the buffer capacity of the system and the efficiency of substrate-to-biogas conversion. When the Fe-BC concentration was 16 g·L −1 , the cumulative biogas production reached 329.42 mL·g-VS −1 , which was 49.7% higher than the blank group, and the lag period was 3.55 d, which was 42% shorter than the blank group. Mechanistic studies have shown that Fe-BC increased the concentration of coenzyme F 420 and the conductivity of the digestate in the co-digestion system, which increased the activity of methanogens in the anaerobic digestion system, thereby promoting methanogenesis.

Keywords: anaerobic digestion; biochar; iron-loaded biochar; sewage sludge; food waste (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
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