Fenitrothion is an organophosphorus insecticide widely used in Sahelian countries. However, fenitrothion undergoes rapid degradation, generating many by-products, the main one being 3-methyl-4-nitrophenol (MNP) known to be hazardous for humans and the environment. The intensive use of fenitrothion has led to environmental contamination, raising concerns about water quality and human health. The current study evaluated the efficiency of nanofiltration membranes in rejecting MNP from water. The objective was to treat water samples containing 1 mg L−1 of MNP, aiming to reduce the concentration below 0.1 mg L−1 to meet the criteria for clean irrigation water. The tested membranes were dNF40, dNF80, and NF90, three performant and low-cost commercial membranes. A UV–visible spectrophotometer was used to monitor MNP concentrations. Among these membranes, dNF40, a hollow fiber membrane based on layer-by-layer technology, showed the best performance for MNP rejection by achieving 96% of MNP retention at 8 bars. Peclet number revealed that mass transfer through the membrane occurred mainly by solution-diffusion, which explained well the success of dNF40. Moreover, the filtration process generates an MNP oncentrate that requires further treatment. We proposed for the first time the use of a fungal-based microbial fuel cell (MFC) to treat the nonfiltered concentrate. The obtained results revealed that the selected fungus, Trichoderma harzianum, could degrade MNP in the concentrate according to first-order degradation kinetics, with a constant rate of 0.18 h−1 and a half-degradation time of 3.85 h. Simultaneously, the MFC generates an electric current achieving a maximum power density of 7 mW.m−3 and an optimal MFC resistance of 7333 Ω.

3-methyl-4-nitrophenol · Nanofiltration · Layer-by-layer · Trichoderma harzianum · Microbial fuel cell