Enhanced 2,4,6-trichlorophenol anaerobic degradation by FeO supported on water hyacinth biochar for triggering direct interspecies electron transfer and its use in coal gasification wastewater treatment.

FeO supported on water hyacinth biochar (FeO/WHB) was successfully used in anaerobic degradation of 2,4,6-trichlorophenol and coal gasification wastewater (CGW). Chemical oxygen demand removal efficiency and methane production were significantly improved to 98.9% and 2.0 L with FeO/WHB assisted. FeO/WHB facilitated the conversion of CO to methane and reduce H production. A higher coenzyme F concentration of 1.32 μmol/(g-mixed liquor volatile suspended solids) was found with the presence of FeO/WHB, which might result in a faster conversion of acetate to methane. More interspecific signal molecules, lower diffusible signal factor, and higher mean particle size indicated that FeO/WHB accelerated the sludge granulation process. Microbial community analysis revealed that enriched bacteria Geobacter along with archaea Methanothrix and Methanosarcina may be involved in direct interspecies electron transfer by FeO/WHB stimulation, enhancing the performance of 2,4,6-trichlorophenol fermentation. It is shown that use of FeO/WHB is feasible for enhanced CGW treatment.