Enhanced 2,4,6-trichlorophenol anaerobic degradation by Fe3O4 supported on water hyacinth biochar for triggering direct interspecies electron transfer and its use in coal gasification wastewater treatment

Fe 3 O 4 supported on water hyacinth biochar (Fe 3 O 4 /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 Fe 3 O 4 /WHB assisted. Fe 3 O 4 /WHB facilitated the conversion of CO 2 to methane and reduce H 2 production. A higher coenzyme F 420 concentration of 1.32 μmol/(g-mixed liquor volatile suspended solids) was found with the presence of Fe 3 O 4 /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 Fe 3 O 4 /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 Fe 3 O 4 /WHB stimulation, enhancing the performance of 2,4,6-trichlorophenol fermentation. It is shown that use of Fe 3 O 4 /WHB is feasible for enhanced CGW treatment.