Experimental Investigation of a Trickle Bed Bioreactor: Hydrodynamics To Biodegradation

Abstract

Experimental investigations have been carried out to study the performance of trickle bed bioreactor in degrading, the most common pollutant; phenol in synthetic water. The effect of key parameters that play predominate role such as hydrodynamic, mass transfer and microbial degradation were characterized under different conditions such as at various superficial liquid velocity, superficial gas velocity and phenol concentrations. The experiments were conducted in a laboratory scale trickle bed bioreactor with cylindrical plexiglas column of height 1.28 m and internal diameter of 0.091 m. Air, Phenol solutions and water and glass beads are used as gas, liquid and solid phases. In hydrodynamic studies, the effect of superficial liquid and gas velocities and concentration of phenol solutions on pressure drop and dynamic liquid saturation were studied. It was observed that both pressure drop and dynamic liquid saturation increases with superficial liquid velocity. With increasing superficial gas velocity pressure drop increases but dynamic liquid saturation decreases. In mass transfer studies, the effect of superficial liquid and gas velocities were studied. The results shows that both solid-liquid, gas-liquid mass transfer coefficients increase with increase in superficial liquid and gas velocities. Microbial degradation study on phenol was investigated by using a microbe, Pseudomonas putida in trickle bed bio reactor. The effect of initial phenol concentration (100 to 1500 ppm) and liquid flow rate (2-4 LPM) were studied. The analysis shows that the microbe, Pseudomonas putida is capable of degrading 1000 ppm phenol solution within 54 hours completely. The impact on rate of biodegradation was successfully determined between external mass transfer and biochemical reaction by correlating Colburn factor (JD) and Reynolds number (NRe) as (1 ) Re * n D J K N   , in which n and K values for present investigation are 0.97, 5.7 respectively