Coupling granular activated carbon and exogenous hydrogen to enhance anaerobic digestion of phenol via predominant syntrophic acetate oxidation and hydrogenotrophic methanogenesis pathway

Anaerobic digestion is a promising biological method for treating phenol-containing wastewater. However, the low methane yield of phenol due to the biological toxicity limits its potential application. This study presents a novel method to enhance the conversion rate of phenol to methane by coupling of granular activated carbon and exogenous hydrogen (GAC/H2). The cumulative methane production in the GAC/H-2, H-2, GAC, and control groups were 408.2 +/- 16.2, 336.5 +/- 5.7, 287.2 +/- 26. 2, and 258.1 +/- 8.6 mL CH4/g COD, respectively. Compared with the control group, the hydrogenotrophic methanogenic activity and electron transfer activity of GAC/H-2 group were increased by 403.9 and 367.4%, respectively. The results of the 16SrRNA analysis indicated GAC enhanced the relative abundances of Syntrophus and Syntrophorhabdus, and hydrogen promoted the relative abundances of Cryptanaerobacter, Aminicenantes, and Methanobacterium. Therefore, the coupling of GAC and exogenous hydrogen promoted a dominate SAO-HM pathway to convert phenol to methane.

Automated summary

This study demonstrates a novel method to enhance the conversion rate of phenol to methane by coupling granular activated carbon and exogenous hydrogen (GAC/H2). The results show that the coupling of GAC and hydrogen significantly increased methane production compared to the control group. The enhancement of methane production was associated with changes in microbial communities, with GAC enhancing specific bacteria and hydrogen promoting methane-producing microorganisms.