Gas–liquid mass transfer studies in inverse fluidized bed biofilm reactor for the biodegradation of industrial effluent rich in phenolic compounds

Abstract

Gas-liquid mass transfer studies were carried out in inverse fluidized bed biofilm reactor (IFBBR) for the biodegradation of phenol. Studies were done to analyze the effect of superficial air velocity (U g ), gas holdup (E g ), and biofilm characteristics such as biofilm thickness, biofilm dry density, suspended and attached biomass concentration, and bioparticle density on oxygen transfer rate (OTR) and gas-liquid volumetric mass transfer coefficient (k L a) for different superficial air velocities and various particle sizes (2.9, 3.5, and 3.8 mm). Average OTR and k L a was found to be high [(OTR) avg. 5 0.0159 min 21 ; (k L a) avg. 5 1.8823 g/(L min)] for the particle size of 3.5 mm at the optimum superficial air velocity (U gm ) of 0.220 m/s which created high turbulence with smaller bubble size. Higher volumetric mass transfer coefficient and OTR resulted in higher percentage of Chemical Oxygen Demand (COD) removal (98%) and phenol degradation (100%) in IFBBR. The gas holdup dominated over the smaller size bubbles resulting in higher mass (oxygen) transfer rate. Thin, dense, and stable biofilm was produced at U gm . Above U gm , thickness of the biofilm was increased where the detachment force did not control the outgrowth of biofilm anymore and thus the k L a was found to be decreasing. V C 2015 American Institute of Chemical Engineers Environ Prog, 35: 433-438, 2016

Investigation of flow dynamic characteristics of inverse fluidized bed biofilm reactor for degrading pharmaceutical based biomedical wastewater

“…When the increase rate of ε g dominates over that of d b , the k L a increases. Because of these two competing effects, the increasing trend of k L a becomes insignificant with increasing U g [24]. Thus at the optimal condition of U g , ε g dominates over the bubble size d b and have a significant effect in increasing the mass transfer rate and thereby the COD removal efficiency.…”

“…During the bio-treatment of biomedical wastewater in IFBBR, samples were collected at regular intervals of time to determine COD, pH, oxygen transfer rate (OTR), volumetric mass transfer coefficient (k L a), biofim thickness, biofilm dry density and pH. All the determinations were done according to standard procedures and methods [19] whereas the biofilm thickness and dry density of biofilm were estimated from the net weight of the bioparticles [24][25][26]. uniform concentration of bio-particles throughout the reactor [27][28][29].…”

Removal of Aniline and Benzothiazole Wastewaters Using an Efficient MnO2/GAC Catalyst in a Photocatalytic Fluidised Bed Reactor

“…The size of the activated carbon particles modified with MnO 2 is a relevant property required for the operation of an FBR [54]. The Geldart classification is one of the most useful ways of classifying solids [1], and it is usually applied to an FBR in group B (with a size between 100 and 800 µm) and group D (larger than 1 mm) particles [62]. Figure 4 shows the particle-size distribution assessed by laser diffraction spectrometry.…”