Electrical stress and acid orange 7 synergistically clear the blockage of electron flow in the methanogenesis of low-strength wastewater

Ze-Chong Guo; Min-Hua Cui; Chun-Xue Yang; Hong-Liang Dai; Tong-Yi Yang; Lin-Zhi Zhai; Yong Chen; Wen-Zong Liu; Ai-Jie Wang

doi:10.1016/j.ese.2024.100410

Electrical stress and acid orange 7 synergistically clear the blockage of electron flow in the methanogenesis of low-strength wastewater

Environ Sci Ecotechnol. 2024 Mar 13:20:100410. doi: 10.1016/j.ese.2024.100410. eCollection 2024 Jul.

Authors

Ze-Chong Guo^{1

2

3}, Min-Hua Cui⁴, Chun-Xue Yang⁵, Hong-Liang Dai¹, Tong-Yi Yang¹, Lin-Zhi Zhai¹, Yong Chen³, Wen-Zong Liu^{2

6}, Ai-Jie Wang^{2

6}

Affiliations

¹ School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212100, China.
² State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
³ School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁴ Jiangsu Key Laboratory of Anaerobic Biotechnology, Jiangnan University, Wuxi, 214122, China.
⁵ School of Geography and Tourism, Harbin University, Harbin, 150001, China.
⁶ School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen, 518055, China.

Abstract

Energy recovery from low-strength wastewater through anaerobic methanogenesis is constrained by limited substrate availability. The development of efficient methanogenic communities is critical but challenging. Here we develop a strategy to acclimate methanogenic communities using conductive carrier (CC), electrical stress (ES), and Acid Orange 7 (AO7) in a modified biofilter. The synergistic integration of CC, ES, and AO7 precipitated a remarkable 72-fold surge in methane production rate compared to the baseline. This increase was attributed to an altered methanogenic community function, independent of the continuous presence of AO7 and ES. AO7 acted as an external electron acceptor, accelerating acetogenesis from fermentation intermediates, restructuring the bacterial community, and enriching electroactive bacteria (EAB). Meanwhile, CC and ES orchestrated the assembly of the archaeal community and promoted electrotrophic methanogens, enhancing acetotrophic methanogenesis electron flow via a mechanism distinct from direct electrochemical interactions. The collective application of CC, ES, and AO7 effectively mitigated electron flow impediments in low-strength wastewater methanogenesis, achieving an additional 34% electron recovery from the substrate. This study proposes a new method of amending anaerobic digestion systems with conductive materials to advance wastewater treatment, sustainability, and energy self-sufficiency.

Keywords: Acid orange 7; Conductive carrier; Electrical stress; Electron transfer; Methanogenesis.