Biofiltration of ethyl acetate by Pseudomonas putida immobilized on walnut shell

► Biofilter showed effective removal of ethyl acetate under high loading conditions. ► Natural packing media provided low pressure drop during the operation period. ► Treated walnut shell had high porosity, surface area and water holding capacity. ► Removal efficiency of 99% was achieved at inlet concentrations lower than 430 ppm. ► Mathematical models were fitted to experimental data for two different EBRTs.