Kinetics of the removal of mono-chlorobenzene vapour from waste gases using a trickle bed air biofilter.

In this work, the removal of monochlorobenzene (CB) vapors from air was studied, for the first time, in a non-inoculated, laboratory-scale, aerobic biofilter. The influence of three parameters on the bioprocess has been evaluated: the rate of nitrogen supplied to the bed, the inlet concentration of CB, and the flow rate. The CB inlet concentration was varied between 0.3 and 3.2 g m−3, at a constant flow rate of 1.0 m3 h−1. Removal rates of greater than 90% were achieved for CB inlet concentrations of up to 1.2 g m−3. Then the flow rate was varied from 0.5 to 3.0 m3 h−1 with a constant inlet concentration (1.2 g m−3). Maximum elimination capacities (70 g m−3 h−1) were reached for contact times of greater than 60 s. The study of varying flow rates also permitted evaluation of a first order macrokinetic constant (1.1 × 10−2 s−1) for the CB biodegradation. Finally, the optimum nitrogen input value was found to lie between 0.3 and 0.4 g N h−1 and gave rise to elimination capacities as high as 70 g m−3 h−1 for an inlet load of near 80 g m−3 h−1. Copyright © 2003 Society of Chemical Industry

Elimination of chlorobenzene vapors from air in a compost-based biofilter

This study presents a comparison of the efficiency of a bioscrubber and a biotrickling filter (BTF) for the removal of ethyl acetate (EA) vapour from a waste gas stream, under the same operating conditions. The maximum EA elimination capacity achieved in the bioscrubber was 550 g m−3 h−1 with removal efficiency higher than 96%. For higher EA loadings the bioscrubber was oxygen limited, which caused incomplete EA biodegradation. When pure oxygen was fed to the bioscrubber at a rate of 0.02 L min−1, the bioscrubber recovered and could treat higher EA loadings without any oxygen limitation. The BTF achieved EA elimination capacity of 600 g m−3 h−1 with removal efficiency higher than 97% and the dissolved oxygen concentration remained substantially higher than in the bioscrubber. However, severe channelling and blockage of the spray nozzle occurred due to the excessive biomass growth. Overall, the bioscrubber system was easier to operate and control than the BTF, while an enhancement of the oxygen mass transfer in the bioscrubber could potentially increase its performance by up to three times. Copyright © 2005 Society of Chemical Industry

C.J Mpanias

Papers

Biocatalytic removal of mono-chlorobenzene vapor in trickling filters