title: Effect of feed to microbe ratios on anaerobic digestion of Chinese cabbage waste under mesophilic and thermophilic conditions: biogas potential and kinetic study.
abstract: The objective of this study was to investigate the effect of the feed-to-microbe (F/M) ratios on anaerobic digestion of Chinese cabbage waste (CCW) generated from a kimchi factory. The batch test was conducted for 96 days under mesophilic (36.5 °C) (Experiment I) and thermophilic (55 °C) conditions (Experiment II) at F/M ratios of 0.5, 1.0 and 2.0. The first-order kinetic model was evaluated for methane yield. The biogas yield in terms of volatile solids (VS) added increased from 591 to 677 mL/g VS under mesophilic conditions and 434 to 639 mL/g VS under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. Similarly, the volumetric biogas production increased from 1.479 to 6.771 L/L under mesophilic conditions and from 1.086 to 6.384 L/L under thermophilic conditions when F/M ratio increased from 0.5 to 2.0. The VS removal increased from 59.4 to 75.6% under mesophilic conditions and from 63.5 to 78.3% under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. The first-order kinetic constant (k, 1/day) decreased under the mesophilic temperature conditions and increased under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. The difference between the experimental and predicted methane yield was in the range of 3.4-14.5% under mesophilic conditions and in the range of 1.1-3.0% under thermophilic conditions. The predicted methane yield derived from the first-order kinetic model was in good agreement with the experimental results.
authors.affiliation: Department of Biological and Agricultural Engineering, University of Idaho, ID, USA. Electronic address: gopikafle1982@gmail.com.
authors.forename: Gopi Krishna
authors.initials: GK
authors.lastname: Kafle
authors.affiliation: Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164, USA.
authors.forename: Sujala
authors.initials: S
authors.lastname: Bhattarai
authors.affiliation: Department of Biosystems Engineering, Kangwon National University, Chuncheon, Kangwon-do, Republic of Korea. Electronic address: shkim@kangwon.ac.kr.
authors.forename: Sang Hun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Biological and Agricultural Engineering, University of Idaho, ID, USA.
authors.forename: Lide
authors.initials: L
authors.lastname: Chen
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D001937:Brassica / Q000378:metabolism*; D007700:Kinetics
keywords: Anaerobic digestion; Chinese cabbage waste (CCW); Feed to microbe ratio (F/M); Kinetic study; Mesophilic and thermophilic temperature