Inhibition of volatile fatty acids on methane production kinetics during dry co-digestion of food waste and pig manure

Jiang, Yan and Dennehy, Conor and Lawlor, Peadar G. and Hu, Zhenhu and McCabe, Matthew and Cormican, Paul and Zhan, Xinmin and Gardiner, Gillian E. (2018) Inhibition of volatile fatty acids on methane production kinetics during dry co-digestion of food waste and pig manure. Waste Management, 79. pp. 302-311. ISSN 0956-053X

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Abstract

Compared with wet digestion, dry digestion of organic wastes reduces reactor volume and requires less energy for heating, but it is easily inhibited by high volatile fatty acid (VFA) or ammonia concentration. The inhibition on methane production kinetics during dry co-digestion of food waste and pig manure is rarely reported. The aim of this study was to explore the inhibition mechanisms and the microbial interactions in food waste and pig manure dry co-digestion systems at different inoculum rates (25% and 50% based on volatile solids) and food waste/pig manure ratios (0:100, 25:75, 50:50, 75:25 and 100:0 based on volatile solids). The results showed that the preferable operation conditions were obtained at the inoculum rate of 50% and food waste/pig manure ratio of 50:50, with a specific methane yield of 263 mL/g VSadded. High VFA concentration was the main inhibition factor on methane production, and the threshold VFA inhibition concentrations ranged 16.5–18.0 g/L. Syntrophic oxidation with hydrogenotrophic methanogenesis might be the main methane production pathway in dry co-digestion systems due to the dominance of hydrogenotrophic methanogens in the archaeal community. In conclusion, dry co-digestion of food waste and pig manure is feasible for methane production without pH adjustment and can be operated stably by choosing proper operation conditions.

Item Type:	Article
Additional Information:	Funding Information: Funding for this study was provided by the Green Farm project supported by a Science Foundation Ireland Investigator Project Award (Ref: 12/IP/1519). The authors are also grateful for the support of EU COST Action of ES1302 (European Network on Ecological Functions of Trace Metals in Anaerobic Biotechnologies). Xinmin is also grateful for the support of the Natural Science Foundation of China (Ref: 51728801). Publisher Copyright: © 2018 Elsevier Ltd
Uncontrolled Keywords:	/dk/atira/pure/subjectarea/asjc/2300/2311
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Depositing User:	Admin SSL
Date Deposited:	19 Oct 2022 23:02
Last Modified:	13 Jun 2023 16:05
URI:	http://repository-testing.wit.ie/id/eprint/3721

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