title: Producing desulfurized biogas through removal of sulfate in the first-stage of a two-stage anaerobic digestion.
abstract: In the present work, a two-stage anaerobic digestion system (TSADS) was newly designed to produce biogas with a greatly reduced H2S content. The role of first (sulfidogenic)-stage digester was not only acidogenesis but also sulfidogenesis (sulfate reduction to H2S), which would minimize the input of H2S-producing source in the followed second (methanogenic)-stage digester. For the coexistence of acidogens and sulfate reducing bacteria (SRB) in the sulfidogenic-stage digester, it was found that pH played a crucial role. The acidogenic activity was not affected within a pH range of 4.5-6.0, while it was important to maintain a pH at 5.5 to achieve a sulfate removal efficiency over 70%. The highest sulfate removal attained was 78% at a hydraulic retention time (HRT) of 5 h at pH 5.5 ± 0.1. The H2S content in the biogas produced in the conventional single-stage digester (SSAD), used as a control, reached 1,650 ± 25 ppmv. In contrast, the biogas produced in the methanogenic-stage digester of the developed process had an H2S content of 200 ± 15 ppmv. Microbial analysis, done by the next generation sequencing technique, clearly showed the changes in community under different operating conditions. Desulfovibrio bastinii (4.9%) played a key role in sulfate removal in the sulfidogenic-stage of the TSADS owing to its characteristics of a short doubling time and growth in an acidic environment. Biotechnol. Bioeng. 2017;114: 970-979. © 2016 Wiley Periodicals, Inc.
authors.affiliation: College of Agriculture, Forestry and Natural Resource Management, University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, Hawaii, 96720.
authors.forename: Yeo-Myeong
authors.initials: YM
authors.lastname: Yun
authors.affiliation: College of Agriculture, Forestry and Natural Resource Management, University of Hawaii at Hilo, 200 W. Kawili Street, Hilo, Hawaii, 96720.
authors.forename: Shihwu
authors.initials: S
authors.lastname: Sung
authors.affiliation: Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Hang-Sik
authors.initials: HS
authors.lastname: Shin
authors.affiliation: Department of Civil and Environmental Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Jong-In
authors.initials: JI
authors.lastname: Han
authors.affiliation: Department of Environmental Engineering, Chonbuk National University, 567 Baekjedae-ro, Deokjin-gu, Jeonju, Jeonbuk 561-756, Republic of Korea.
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Kim
authors.affiliation: Department of Civil Engineering, Inha University, 100 Inha-ro, Nam-gu, Incheon, Republic of Korea.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D003901:Desulfovibrio / Q000378:metabolism; D012722:Sewage / Q000382:microbiology; D013431:Sulfates / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D056804:Biofuels; D012722:Sewage; D013431:Sulfates
keywords: H2S; desulfurized biogas production; microbial community analysis; organic wastes; sulfate reducing bacteria; two-stage anaerobic digestion system