Impact of carbon-based conductive materials on performance and microbial community composition during anaerobic digestion of butanol-octanol wastewater.

Butanol-octanol wastewater (BOW) from coal syngas conversion with hazardous and high salinity could hinder anaerobic digestion (AD). The carbon-based conductive materials (CCM) appear viable for enhancing the AD capability of BOW. Nevertheless, the potential mechanisms of different CCM types on AD of BOW remain unclear. The three different morphologies of CCM, powdered activated carbon (PAC), granular activated carbon (GAC), and carbon fiber cloth (CFC), were employed to improve methane conversion rate in AD of actual BOW. Results indicated that, compared to other carbon materials, more aromatic functional groups on the surface of GAC promoted electron transfer and notably increased degradation of 3-heptanone in BOW and methanogenic. Microbial community structure analysis showed Geobacter on GAC increased to 30.99 %, while Syntrophomonas and Methanosaeta in the sludge increased by 5.05 % and 7.7 %, respectively. The methane conversion rate of BOW was increased by promoting direct interspecies electron transfer (DIET) through GAC.