Effect of activated carbon as a buffer for biofilters treating dynamically varying VOC concentrations

Document Type

Conference Proceeding

Publication Date

12-1-2004

Abstract

The concentrations of volatile organic compounds (VOCs) in air emissions from industrial operations often vary as a function of time. These dynamic loading conditions present a challenge in design and operation of biofilters treating such off-gases. In the experiments described in this paper, the feasibility of using an integrated system consisting of a column packed with granular activated carbon (GAC) in series before a biofilter was tested to determine its potential for mitigating the effects of unsteady-state loading. The model waste gas stream contained a two-component mixture of acetone and toluene at influent concentrations of 430 ppmv and 100 ppm v, respectively. To simulate loading conditions expected from an industrial process with intermittent operation, contaminated air was supplied for 8 hours per day, and uncontaminated air was supplied for 16 hours per day. The system was operated with an empty bed residence time (EBRT) of 10 seconds for the activated carbon column and 58 seconds for the biofilter. The activated carbon column was able to effectively dampen the effects of the intermittent loading. Under quasi steady-state conditions, the contaminated gas stream exiting the activated carbon column and entering the biofilter had an essentially constant toluene concentration. The acetone concentration varied with time but to a much lower extent than would have occurred in the absence of the activated carbon column. The biofilter was able to achieve nearly complete removal of both acetone and toluene within 20 days following startup. Data are presented which clearly demonstrate that a GAC load-dampening system installed in series before a biofilter can be applied successfully to air streams contaminated by solvent mixtures.

Publication Source (Journal or Book title)

Proceedings of the Air and Waste Management Association's Annual Meeting and Exhibition

First Page

1463

Last Page

1473

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