Impact of graphene oxide functionalized with nano-magnetite on swine wastewater anaerobic treatment

This study evaluated the impact of graphene oxide functionalized with nano-magnetite (GO-Fe₃O₄) on the anaerobic treatment of swine wastewater (SW). The experiment was conducted in glass reactors with 200 mL of reaction volume, operating in fed-batch mode in three treatment cycles, each with 35 days. The evaluated doses of GO-Fe₃O₄ were 3 mg L^-1 (1 mg gVSS^-1) and 150 mg L^-1 (50 mg gVSS^-1). In the third cycle, GO-Fe₃O₄ (150 mg L^-1) increased the biochemical methane potential by 17 %, the biogas production potential by 18 %, the methane production rate constant by 31 %, the maximum methane production rate by 32 %, and reduced the lag phase time by 25 %. Potential direct interspecies electron transfer partners are Midas g 156 and Clostridium sensu stricto 1 with Methanobacterium beijingense and Methanothrix soehngenii. GO-Fe₃O₄ is a powerful and unique material for improving methane and biogas production via SW anaerobic treatment.