Evaluation and modeling of textile effluent biodecoloration by Heterobasidion annosum immobilized in up-flow packed-bed bioreactor with conditions approaching plug-flow
Academic Article in Scopus
The biodecoloration of an industrial textile effluent with an indigo blue dye concentration of 104.80 mg L¿¹ in an up-flow packed-bed bioreactor with Heterobasidion annosum immobilized under operational conditions to consider the approach plug-flow behavior was evaluated and modeled. The bioreactor operated with defined geometric parameters ( L/d t > 5, L/d p > 50, ¿ = 0.946) as criteria that, together with the packed-bed Reynolds number ( Re p < 10), enabled considering an approach to the hydrodynamics of plug flow. Biodecoloration was quantitatively determined through spectrophotometric absorbance measurements at 610 nm, with dye removal efficiencies from 54.6% to 93.9% across several flow rates. A steady-state mathematical model incorporating a mass balance for an up-flow packed-bed bioreactor and Monod-like kinetics was developed, and its descriptive capability was verified through a global goodness-of-fit assessment (R¿L2= 0.9902, RMSD=0.1171). The model yielded a parameter of the apparent maximum specific biodecoloration rate associated with biomass enzymatic capability ( q max ) of 0.00770 ± 0.00079 mg mg¿¹ h¿¹ . Simulations demonstrated that increasing the concentration of immobilized biomass in the bed significantly reduced the residence time to reach steady-state dye removal. The Damköhler number ( Da I ) was used to identify the biodecoloration rate-limiting step, which was limited by convective transport at low flow rates ( Re p < 1.5) and by reaction kinetics at higher flow rates ( Re p > 1.5). This study presents an engineering framework that combines hydrodynamic criteria with modeling, offering a predictive, scalable strategy for the biodecoloration of textile effluents in fungal-packed-bed bioreactors.
