Enhanced degradation of high-concentrated 2,4,6 trichlorophenol-containing wastewater by micron-grade high iron-containing fly ash/loofah sponge biochar: Metagenomic functional succession

In order to strengthen the treatment of phenolic wastewater by anaerobic biotechnology, micron-grade high iron-containing fly ash/loofah sponge biochar (MHIFA/LsBC) was prepared and added to anaerobic activated sludge. It was domesticated and cultured in anaerobic bottle by a constant temperature oscillation incubator. Its promoting effect on the anaerobic degradation of high-concentrated 2,4,6-trichlorophenol (2,4,6-TCP) wastewater and its effect on the composition and function of microbial community were studied. The results indicated that with MHIFA/LsBC, the final removal rates of COD and 2,4,6-TCP in R1 (75.6% and 75.1%) were 2.1 and 1.81 times than those of the control group, respectively. The maximum methane yield was 107.25 mL/d. MHIFA/LsBC addition resulted in higher biomass and conductivity, and simultaneously increased the concentration of EPS and coenzyme F420. Microbial community analysis indicated that the enriched electrogenic bacteria Pseudomonas might perform DIET with Methanothrix through bioelectrical connection assisted by MHIFA/LsBC, and promote the anaerobic degradation of 2,4,6-TCP. As the functional genus induced by MHIFA/LsBC, Pseudomonas promoted the degradation and transformation of phenolic pollutants, and Azotobacter played a keystone role in metabolism for hydrogen production by preserving the NADH/NAD+ balance.