The trade-offs and effect of carrier size and oxygen-loading on gaseous toluene removal performance of a three-phase circulating-bed biofilm reactor.
We conducted a series of steady-state and short-term experiments on a three-phase circulating-bed biofilm reactor (CBBR) for removing toluene from gas streams. The goal was to investigate the effect of macroporous-carrier size (1-mm cubes versus 4-mm cubes) on CBBR performance over a wide range of oxygen loading. We hypothesized that the smaller biomass accumulation with 1-mm carriers would minimize dissolved-oxygen (DO) limitation and improve toluene removal, particularly when the DO loading is constrained. The CBBR with 1-mm carriers overcame the performance limitation observed with the CBBR with 4-mm carriers: i.e., oxygen depletion inside the biofilm. The 1-mm carriers consistently gave superior removal of toluene and chemical oxygen-demand, and the advantage was greatest for the lowest oxygen loading and the greatest toluene loading. The 1-mm carriers achieved superior performance because they minimized the negative effects of oxygen depletion, while continuing to provide protection from excess biomass detachment and inhibition from toluene.
Sang
B-I
BI
Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3109, USA. b-sang@northwestern.edu
Yoo
E-S
ES
Kim
B J
BJ
Rittmann
B E
BE
D000393:Air Pollutants / Q000378:metabolism; D018441:Biofilms; D018533:Biomass; D019149:Bioreactors; D005740:Gases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism*
D000393:Air Pollutants; D005740:Gases; D014050:Toluene; D010100:Oxygen