Methanotrophic oxidation of organic micropollutants and nitrogen upcycling in a hybrid membrane biofilm reactor (hMbFR) for simultaneous O₂ and CH₄ supply

Pharmaceuticals and other organic micropollutants (OMPs) present in wastewater effluents are of growing concern, as they threaten environmental and human health. Conventional biological treatments lead to limited removal of OMPs. Methanotrophic bacteria can degrade a variety of OMPs. By employing a novel bubble-free hybrid membrane biofilm bioreactor (hMBfR), we grew methanotrophic bacteria at three CH₄ loading rates. Biomass productivity and CH₄ loading showed a linear correlation, with a maximum productivity of 372 mg-VSS∙L⁻¹∙d⁻¹, with corresponding biomass concentration of 1117.6 ± 56.4 mg-VSS∙L⁻¹. Furthermore, the biodegradation of sulfamethoxazole and 1H-benzotriazole positively correlated with CH₄ oxidation rates, with highest biodegradation kinetic constants of 3.58 L∙g⁻¹∙d⁻¹ and 5.42 L∙g⁻¹∙d⁻¹, respectively. Additionally, the hMBfR recovered nutrients as microbial proteins, with an average content 39% DW. The biofilm community was dominated by Methylomonas, while the bulk was dominated by aerobic heterotrophic bacteria. The hMBfR removed OMPs, allowing for safer water reuse while valorising CH₄ and nutrients.