Magnetite nanoparticles (Fe3O4 NPs) was firstly used to enhance pollutants removal during coal gasification wastewater (CGW) treatment in anaerobic digestion (AD) system. Bench-scale results revealed that 200 mg/L and 20-40 nm of Fe3O4 NPs addition resulted in a maximum removal capacity of total phenol (TPh) at a temperature of 36 °C and hydraulic retention time (HRT) of 36 h. Meanwhile, Fe3O4 NPs addition reduced the oxidation reduction potential (ORP) values and biological toxicity, and enhanced the stability of AD system. Pilot-scale results showed that the TPh and chemical oxygen demand (COD) removal efficiency (53% and 49%) were obtained with the optimal dosage of Fe3O4 NPs. Moreover, electron nanowires may be established with Fe3O4 NPs assisted to perform direct interspecies electron transfer (DIET) among Geobacter, Pseudomonas and Methanosaeta species, and finally enhanced the pollutants removal efficiency.
Keywords: Anaerobic digestion; Coal gasification wastewater; Enhancement mechanisms; Magnetite nanoparticles; Microbial community.
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