Carbon cloth facilitates semi-continuous anaerobic digestion of organic wastewater rich in volatile fatty acids from dark fermentation

• Published in: Environmental pollution (1987) Vol. 272; p. 116030
• Main Authors: Feng, Dong, Xia, Ao, Liao, Qiang, Nizami, Abdul-Sattar, Sun, Chihe, Huang, Yun, Zhu, Xianqing, Zhu, Xun
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-03-2021
• Subjects: Anaerobic digestion; Anaerobiosis; Biomethane; Bioreactors; Carbon; Carbon cloth; Direct interspecies electron transfer; Fatty Acids, Volatile; Fermentation; Methane; Sewage; Waste Water; Carbon cloth; Biomethane; Anaerobic digestion; Direct interspecies electron transfer
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2020.116030

The anaerobic digestion of wastewater rich in volatile fatty acids (VFAs) provides a sustainable approach for methane production whilst reducing environmental pollution. However, the anaerobic digestion of VFAs may not be stable during long-term operation under a short hydraulic retention time. In this study, conductive carbon cloth was supplemented to investigate the impacts on the anaerobic digestion of VFAs in wastewater sourced from dark fermentation. The results demonstrated that the failure of anaerobic digestion could be avoided when carbon cloth was supplemented. In the stable stage, the methane production rate with carbon cloth supplementation was improved by 200–260%, and the chemical oxygen demand (COD) removal efficiency was significantly enhanced compared with that in the control without carbon cloth. The relative abundance of potential exoelectrogens on the carbon cloth was increased by up to 8-fold compared with that in the suspension. Electrotrophic methanogens on the carbon cloth were enriched by 4.2–17.2% compared with those in the suspension. The genera Ercella and Petrimonas along with the methanogenic archaea Methanosaeta and Methanosarcina on the carbon cloth may facilitate direct interspecies electron transfer, thereby enhancing methane production.
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•Carbon cloth facilitated the conversion of VFAs to methane in wastewater from DF.•Failure of AD under short HRT can be avoided with the addition of carbon cloth.•Potential exoelectrogens Ercella and Petrimonas were enriched on carbon cloth.•Electrotrophic methanogen Methanosarcina was specifically enriched on carbon cloth.
Conductive carbon cloth facilitated the conversion of VFAs to methane in organic wastewater sourced from dark fermentation during AD at an HRT of 10 d in CSTR.