An innovative multistage anaerobic hythane reactor (MAHR): Metabolic flux, thermodynamics and microbial functions

Buchun Si; Hao Yang; Sijie Huang; Jamison Watson; Yuanhui Zhang; Zhidan Liu

doi:10.1016/j.watres.2019.115216

An innovative multistage anaerobic hythane reactor (MAHR): Metabolic flux, thermodynamics and microbial functions

Water Res. 2020 Feb 1:169:115216. doi: 10.1016/j.watres.2019.115216. Epub 2019 Oct 22.

Authors

Buchun Si¹, Hao Yang¹, Sijie Huang¹, Jamison Watson², Yuanhui Zhang³, Zhidan Liu⁴

Affiliations

¹ Laboratory of Environment-Enhancing Energy (E2E), Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture, College of Water Resources and Civil Engineering, China Agricultural University, Beijing, 100083, China.
² Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
³ Laboratory of Environment-Enhancing Energy (E2E), Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture, College of Water Resources and Civil Engineering, China Agricultural University, Beijing, 100083, China; Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
⁴ Laboratory of Environment-Enhancing Energy (E2E), Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture, College of Water Resources and Civil Engineering, China Agricultural University, Beijing, 100083, China. Electronic address: zdliu@cau.edu.cn.

PMID: 31675610
DOI: 10.1016/j.watres.2019.115216

Abstract

Biohythane production from wastewater via anaerobic fermentation currently relies on two-stage physically separated biohydrogen and biomethane reactors, which requires closed monitoring, the implementation of a control system, and cost-intensive, complex operation. Herein, an innovative multistage anaerobic hythane reactor (MAHR) was reported via integrating two-stage fermentation into one reactor. MAHR was constructed using an internal down-flow packed bed reactor and an external up-flow sludge blanket to enhance microbial enrichment and thermodynamic feasibility of the associated bioreactions. The performance of MAHR was investigated for 160 d based on biogas production, metabolic flux and microbial structure in comparison to a typical anaerobic high-rate reactor (up-flow anaerobic sludge blanket (UASB)). A biohythane production with an optimized hydrogen volume ratio (10-20%) and a high methane content (75-80%) was achieved in the hythane zone (M_H) and methane zone (M_M) in MAHR, respectively. In addition, MAHR showed a stronger capability to accommodate a high organic loading rate (120 g COD/L/d), and it enhanced the conversion of organics leading to a methane production rate 66% higher than UASB. Thermodynamic analysis suggested that hydrogen extraction in M_H significantly decreased the hydrogen partial pressure (<0.1% vol) which favored acetogenesis in M_M. Metabolic flux and microbial function analysis further supported the superior performance of MAHR over UASB, which was primarily attributed to enhanced acetogenesis and acetoclastic methanogenesis.

Keywords: Biohythane; Metabolic flux; Methane; Microbial structure; Multistage anaerobic hythane reactor; Thermodynamics analysis.

MeSH terms

Anaerobiosis
Bioreactors*
Methane
Sewage*
Thermodynamics

Substances

Sewage
Methane