Degradation of solvent mixture vapors in a biotrickling filter reactor: impact of hydrophilic components loading and loading release dynamic

[Abstract] Interactions amongst the degradation rates of toluene, xylenes, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), n-butyl acetate (n-BA), and acetone (Ac) were investigated in a biotrickling filter reactor. The reactor was packed with polypropylene High-Flow rings in a counter-current airwater mode of operation. Performance evaluation of the reactor with increased hydrophilic compound loading while maintaining a steady loading rate of hydrophobic components, were evaluated. The dynamic responses of the individual solvent components following a drop of the ketone loading rate are also described in a second phase of experiments. The degradation rate of aromatics became partially inhibited at OLKET of 15 g.m-3.h-1; below this level all of the ketones were totally degraded. Once the organic loading exceeded a value of 40 g.m-3.h-1 the removal efficiency of all the components (except n-BA) began to drop sharply. At OLKET of 85 g.m-3.h-1 the RE of aromatics dropped to below 10 %, that of acetone to 10 %, MEK and MIBK to 20 %, but n-BA removal remained above 97 %. A step-decrease of the OLKET from 85 to 5 g.m-3.h-1 resulted in a rapid increase of REAROM to 30 % (in 20 min). After the decrease, the level of REKET quickly reached 90 %, specifically: for MEK this occurred in about 4 min, for MIBK in about 25 min but for acetone, this was not achieved until after a period of 3.5 h. The significantly longer time period of REAc to achieve the original value was a consequence of: (1) its slower degradation rate resulting from a degradation competition with the other components, (2) the inhibitory effect resulting from acetone unlimited water solubility, and (3) a high quantity of acetone being accumulated in a circulating aqueous medium

Paint solvent components degradation from their mixture along the biotrickling bed height

Czech Science Foundation; 104/05/0194Czech Republic. Ministry of Education, Youth and Sports; MSM 6046137305

Styrene degradation in perlite biofilter: the overall performance characteristics and dynamic response

[Abstract] Styrene’s degradation in a perlite biofilter including the long-term operation, dynamic response to step-changes in inlet concentration and non-use periods were tested. The study was performed in a bench-scale biofilter with ID 100 mm and a bed height of 1 m. Perlite with a particle size of 2 – 4 mm was used as a packing material. An enrichment mixed culture was immobilized on the packing. The inoculum was obtained from a styrene biofilter. Two different loading conditions were tested: (1) Loading with a high inlet concentration and a high residence time. (2) Loading with a low inlet concentration and the low residence time. Both conditions are common in industrial practice. The dynamic response to a repeated step-change in the inlet concentration (from 50 to 200 mg.m-3) was tested. The dynamic behaviour of the restarting period after varying periods of non-use was also investigated. The results demonstrate a high biofilter stability under extreme loading conditions and also during the step-changes of the inlet concentration. The non-use periods tested had almost no effect on the biofilter performance. The maximum outlet concentration after the restarting of the load was 4 mg.m-3, when a 95 hours idle period was used. After shorter idle periods, the outlet styrene concentrations did not exceed 0.6 mg.m-3

FT-IR characterization of biofilms formed on engineered biofiltration media treating volatile organic emissions for the forest products industry

[Abstract] The gaseous emissions from hardboard mill presses at lumber plants contain both volatile and condensable organic compounds, as well as fine wood and other very small particulate material. Biological emissions control for these compounds present several challenges. The biofiltration media provides support and contact between the gas phase contaminants and active microbial cultures attached as biofilms on the media’s surface. As the transformations in the biofilm and the media during optimal biofiltration operations are not well understood, the main aim of this project was to characterize the biofilm formed on the media during the biofiltration process using Fourier Transform Infrared Spectroscopy (FT-IR) and the FT-IR Microscope, and also examine the results along with the performance data of VOC biofiltration field and pilot scale tests. Some differences in the absorbance spectra were observed in the media and biofilm samples collected from the top and the bottom bed of the biofilters. This work suggests that while FT-IR spectral information can provide some useful insights to biofilm coverages and quality within media sections, more work and measurements will be needed to correlate the information to biofiltration performance and optimization

Gasoline biofiltration: an analytic model

[Abstract] We present an analytical method of solution for a pair of models representing the removal of gasoline from air by biofiltration. The experimental data showed that the aromatic components of the gasoline were more readily digested than the aliphatics. The models, involving two or three fitted parameters, fitted the laboratory data well

Modelling the absorption of styrene and acetone on activated carbon and perlite beds

[Abstract] Experimental data from the Institute of Chemical Technology, Prague were analysed to derive some simple models of the rate of adsorption of either styrene or acetone from dilute air mixtures on sterile beds of activated carbon or perlite. It was found that the rate of progress towards the saturation of these beds could be reasonably accurately represented by a first order Lagergren model, where the rate constant had a value in the range 0.0039 to 0.29 min-1