The developed bio-hydrogen fermented waste activated carbon (BHFW-AC) has proven to be a cost effective, highly efficient and eco-friendly adsorbent, an alternative (low cost) source of AC for the removal of Direct Navy Blue-106 (DNB-106). This study investigated the feasibility of BHFW at low temperature (100 °C) using chemical carbonization treatment with H3PO4 for 24 h. The parameters pH, temperature, initial dye concentration and contact time have been optimized by batch experiments to increase the adsorption efficiency of the BHFW-AC. Interestingly, the batch adsorption equilibrium data followed the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich models with the Langmuir isotherm providing the best fit to the equilibrium data. On the other hand, the kinetic data followed closely the pseudo-second-order rate kinetic model. Besides, the thermodynamic study showed that the adsorption was a spontaneous endothermic process.