Assessing the long-term impact of incorporating GAC and Fe&G mediators for enhancing phenol containing simulated wastewater treatment in UASB reactor

Phenol containing wastewater (PCW) is highly toxic and difficult to be treated by traditional methods. This study utilized granular activated carbon (GAC) and Fe (Sponge iron) &GAC (Fe&G) in a laboratory-scale UASB reactor to mitigate the toxicity of phenol containing simulated wastewater (PCSW) and enhance treatment performance. Compared with GAC, Fe&G mediators achieves approximately 7 % and 24 % higher removal rates for COD and phenolic compounds, respectively. The methane accumulation in Fe&G group was about 10 % higher than that in GAC group and 22 % higher than that in blank group. Microbial analysis showed that compared with GAC, Fe&G mediators could enrich Petronas and Methanothrix to intensify Direct Interspecies Electron Transfer (DIET) to augment PCSW treatment and boost methane production. PICRUSt analysis showed that these mediators enriched key genes such as TCA cycle and CO₂ methanogenesis pathway to improve microbial resistance to PCSW toxicity and enhance microbial metabolism. This study provides a new method for anaerobic treatment of highly polluted industrial wastewater.