Effect of carrier size on the performance of a three-phase circulating-bed biofilm reactor for removing toluene in gas stream.
A series of steady-state and short-term experiments on a three-phase circulating-bed biofilm reactor (CBBR) for removing toluene from gas streams were conducted to investigate the effect of macroporous-carrier size (1-mm cubes versus 4-mm cubes, which have the same total surface area) on CBBR performance. Experimental conditions were identical, except for the carrier size. The CBBR with 1-mm carriers (the 1-mm CBBR) overcame the performance limitation observed with the CBBR with 4-mm carriers (the 4-mm CBBR): oxygen depletion inside the biofilm. The 1-mm CBBR consistently had the superior removal efficiencies of toluene and COD, higher than 93% for all, and the advantage was greatest for the highest toluene loading, 0.12 M/m2-day. The 1-mm carriers achieved superior performance by minimizing the negative effects of oxygen depletion, because they had 4.7 to 6.8 times thinner biofilm depths. The 1-mm carriers continued to provide protection from excess biomass detachment and inhibition from toluene. Finally, the 1-mm CBBR achieved volumetric removal capacities up to 300 times greater than demonstrated by other biofilters treating toluene and related volatile hydrocarbons.
Sang
Byoung-In
BI
Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3109, U.S.A. biosang@kist.re.kr
Yoo
Eui-Sun
ES
Kim
Byung J
BJ
Rittmann
Bruce E
BE
D001673:Biodegradation, Environmental; D018441:Biofilms; D018533:Biomass; D019149:Bioreactors; D005740:Gases / Q000378:metabolism*; D010101:Oxygen Consumption; D016062:Porosity; D014050:Toluene / Q000378:metabolism*; D014835:Volatilization
D005740:Gases; D014050:Toluene