Simulation of biodegradation process of phenolic wastewater at higher concentrations in a fluidized-bed bioreactor

Abstract

Experiments were carried out to study the biodegradation of phenolic wastewater using microorganisms in a fluidized-bed bioreactor (FBR). Synthetic wastewater has been used in the study. Experiments were conducted at various conditions of wastewater flow rate, dissolved oxygen (DO) concentration and inlet concentration. The wastewater with feed concentration of phenol as high as 1254 ppm has been successfully biodegraded to 50 ppm in the fluidized-bed bioreactor, whereas feed with concentration up to 1034 ppm could be completely biodegraded (to zero ppm). Biokinetic parameters for the growth of the cells were determined in batch experiments and they were found to be μmax = 1.436 × 10−4 s−1, Ks = 21.92 × 10−3 kg/m3, Ki = 522 × 10−3 kg/m3. Model equations describing the simultaneous diffusion and reaction of phenol and oxygen in the biofilm of the solid particles, were solved using the orthogonal collocation technique to calculate the rate of biodegradation of phenol. The rate of biodegradation predicted by the model was compared with that observed experimentally and the difference between the two was found to be about 12%.