TY - JOUR
T1 - Inhibition of volatile fatty acids on methane production kinetics during dry co-digestion of food waste and pig manure
AU - Jiang, Yan
AU - Dennehy, Conor
AU - Lawlor, Peadar G.
AU - Hu, Zhenhu
AU - McCabe, Matthew
AU - Cormican, Paul
AU - Zhan, Xinmin
AU - Gardiner, Gillian E.
N1 - 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
PY - 2018/9
Y1 - 2018/9
N2 - 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.
AB - 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.
KW - Co-digestion
KW - Dry digestion
KW - Hydrogenotrophic methanogenesis
KW - Microbial community structure
KW - Syntrophic oxidation
KW - VFA inhibition
UR - http://www.scopus.com/inward/record.url?scp=85050932614&partnerID=8YFLogxK
U2 - 10.1016/j.wasman.2018.07.049
DO - 10.1016/j.wasman.2018.07.049
M3 - Article
C2 - 30343759
AN - SCOPUS:85050932614
SN - 0956-053X
VL - 79
SP - 302
EP - 311
JO - Waste Management
JF - Waste Management
ER -