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

Abstract

Fe3O4 supported on water hyacinth biochar (Fe3O4/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 Fe3O4/WHB assisted. Fe3O4/WHB facilitated the conversion of CO2 to methane and reduce H2 production. A higher coenzyme F420 concentration of 1.32 μmol/(g-mixed liquor volatile suspended solids) was found with the presence of Fe3O4/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 Fe3O4/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 Fe3O4/WHB stimulation, enhancing the performance of 2,4,6-trichlorophenol fermentation. It is shown that use of Fe3O4/WHB is feasible for enhanced CGW treatment.