• Journal of Korean Society for Atmospheric Environment
• /
• v.18 no.E2
• /
• pp.79-84
• /
• 2002

The objective of this study was to investigate the biodegradation of ethylene in an activated carbon biofilter inoculated with immobilized microbial consortium. The biofilter performance was monitored in terms of ethylene removal efficiency and carbon dioxide production. The biofilter was capable of achieving ethylene removal efficiency as much as 100% at a residence time of 14 min and an inlet concentration of 290 ppm. Under the same conditions, carbon dioxide with a concentration of up to 546 ppm was produced. Its was found that carbon dioxide was produced at a rate of 87 mg day$\^$-1/, which corresponded to a volume of 0.05 L day$\^$-1/. During operation with an inlet ethylene of 290 ppm, the maximum elimination capacity of the biofilter was 34 g of C$_2$H$_4$m$\^$-3/ day$\^$-1/. The biofilter could provide an attractive treatment technology for removing ethylene, an extremely volatile and slowly adsorbed compound.

• Journal of Environmental Science International
• /
• v.13 no.1
• /
• pp.47-53
• /
• 2004

A biofiltration system using activated carbon/polyurethane composite as solid support inoculated with Bacillus sp. was developed for treating a gaseous stream containing high concentrations of H$_2$S. The effects of operating condition such as the influent H$_2$S concentration and the empty bed contact time (EBCT) on the removal efficiency of H$_2$S were investigated. The biofilter showed the stable removal efficiencies of over 99 ％ under the EBCT range from 15 to 60 sec at the 300 ppmv of H$_2$S inlet concentration. When the inlet concentration of H$_2$S was increased, the removal efficiencies decreased, reaching 95 and 74％, at EBCTs of 10 and 7.5 sec, respectively. The maximum elimination capacity in the biofilter packed with activated carbon/polyurethane composite media was 157 g/m$^3$/hr.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.3
• /
• pp.399-407
• /
• 2006

In this study, an electrical conductive carbon fiber was used as a biofilter matrix to electrochemically improve the biofilter function. A bioreactor system was composed of carbon fiber (anode), titanium ring, porcelain ring, inorganic nutrient reservoir, and VOC reservoir. Electric DC power of 1.5 volt was charged to the carbon fiber anode (CFA) to induce the electrochemical oxidation potential on the biofilter matrix, but not to the carbon fiber (CF). We tested the effects of electrochemical oxidation potential charged to the CFA on the biofilm structure, the bacterial growth, and the activity for metabolic oxidation of VOCs to $CO_2$, According to the SEM image, the biofilm structure developed in the CFA appeared to be greatly different from that in the CF. The bacterial growth, VOCs degradation, and metabolic oxidation of VOCs to $CO_2$ in the CFA were more activated than those in the CF. On the basis of these results, we propose that the biofilm structure can be improved, and the bacterial growth and the bacterial oxidation activity of VOCs can be activated by the electrochemical oxidation potential charged to a biofilter matrix.

• Journal of Korean Society for Atmospheric Environment
• /
• v.17 no.3
• /
• pp.269-276
• /
• 2001

The objective of this study was to investigate the biodegradation of ethylene in an biofilter inoculated with ethylene-oxidizing microorganisms. The biofilter performance was monitored in terms of ethylene removal efficiency and carbon dioxide production. The biofilter was capable of achieving the ethylene removal efficiency as much as 100% at a residence time of 14 min and an inlet concentration of 290 ppm. Under the same conditions, carbon dioxide with a concentration of up to 546 ppm was produced. It was found that carbon dioxide was produced at a rate of 87 mg/day, which corresponded to a volume of 0.05 L/day. Observable features of the ethylene-oxidizing microorganisms, meaning microbial activity occurrence in the biofilter, were investigated with the microscopy analysis.

• Journal of Environmental Science International
• /
• v.14 no.9
• /
• pp.843-849
• /
• 2005

The objective of this research was to investigate the removal efficiencies ofVOCs and odors with newly developed biofilter which was designed to sustain the biofilm constantly on the packed media. Initially, four types of media, for example, fiber, activated carbon, ceramic and the mixture of activated carbon and ceramic(AIC mixture J, were used for packed materials of biofilter. When ethylalcohol was selected as a test gas for media efficiency, fiber and AIC mixture had better removal efficiencies of ethyl alcohol than others. Removal efficiencies for acetaldehyde, ethyl alcohol, butylalcohol, ethylacetate and diethylamine in biofilter with fiber and AIC mixture as packed media were increased as the residence time increased. Butylalcohol, especially, showed the maximum removal efficiency among all used VOCs and odors. In case of ethyl acetate, the difference of removal efficiencies between low and high residence times was wide remarkably.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.1
• /
• pp.24-30
• /
• 1999

A biological filter for treatment of toluene among volatile organic compounds was studied. The investigation was conducted using specially built stainless steel columns packed with granular activated carbon and cold for removal of toluene. The G.A. and mold as filter material was also coated with Pseudomonas putida microorganisms.The biofilter unit was operated in the condition of moisture content vairation at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C equipped with F.I.d detector. The removal efficiency of gaseous toluene was 95% at average inlet concentration of 950 ppm during bio-degradation operating condition. Effective removal efficiency was obtained with moisture content 27.5% at activated carbon and 32% at mold in this study. The effective operating condition were obtained with pH 6-8, temperature 28-42℃ for microbial degradation at gas loading rate of 12.5 l/min in packed material.

• Journal of environmental and Sanitary engineering
• /
• v.13 no.2
• /
• pp.88-94
• /
• 1998

This study was investigated the application of biofiltration using cometabolic process to remediate gaseous toluene that are highly recalcitrant to adsorption, absorption and biodegradation. The investigation was conducted using specially built steel columns packed with granular activated carbon for removal of toluene and G.A.C was also coated with Pseudomonas putida microorganisms by addition of KH$_{2}$PO$_{4}$. The biofilter unit was operated in the condition of dry and 27.5% moisture content at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C. equipped with F.I.D. detector. The removal efficiency of gaseous toluene was 85% at average inlet concentration of 970 ppm during dry operating condition. For gaseous toluene, 91% removal efficient was obtained at the filter material with moisture content and 97% removal efficiency was obtained with Pseudomonas putida microorganisms at gas loading rate of 12.5 l/min.

• Journal of Korean Society for Atmospheric Environment
• /
• v.19 no.3
• /
• pp.325-331
• /
• 2003

A biofilter study was conducted by changing inlet concentration and residence time for the removal of gaseous benzene and ethylene. In addition, carbon dioxide produced from the biofilters was investigated. Over 96% of benzene was removed at the residence times of 2 and 4.3 min, and inlet benzene concentrations of 220∼300 ppm. The ethylene biofilter was capable of achieving ethylene removal efficiency as much as 100％ at a residence time of 14 min, and inlet concentrations of 99∼290 ppm. At a steady state, the carbon dioxide of 409∼611 ppm was produced with an ethylene inlet concentration of 290 ppm. Most of benzene and ethylene were degraded at lower part of the biofilters where more microbial activity occurred.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.2
• /
• pp.218-224
• /
• 2008

Coal-, coconut- and wood-based activated carbons and anthracite were tested to evaluate adsorption and biodegradation performances of chloral hydrate. In the early stage of the operation, the adsorption was the main mechanism for the removal of chloral hydrate, however as increasing populations of attached bacteria, the bacteria played a major role in removing chloral hydrate in the activated carbon and anthracite biofilter. It was also investigated that chloral hydrate was readily subjected to biodegrade. The coal- and coconut-based activated carbons were found to be most effective adsorbents in adsorption of chloral hydrate. Highest populations and activity of attached bacteria were shown in the coal-based activated carbon. The populations and activity of attached bacteria decreased in the order: coconut-based activated carbon > wood-based activated carbon > anthracite. The attached bacteria was inhibited in the removal of chloral hydrate at temperatures below 10$^{\circ}C$. It was more active at higher water temperatures(20$^{\circ}C$ <) but less active at lower water temperature(10$^{\circ}C$>). The removal efficiencies of chloral hydrate obtained by using four different adsorbents were directly related to the water temperatures. Water temperature was the most important factor for removal of chloral hydrate in the anthracite biofilter because the removal of chloral hydrate depended mainly on biodegradation. Therefore, the main removal mechanism of chloral hydrate by applying activated carbon was both adsorption and biodegradation by the attached bacteria. The observation suggests that the application of coalbased activated carbon to the water treatment should be the best for the removal of chloral hydrate.

• Journal of Korean Society on Water Environment
• /
• v.27 no.2
• /
• pp.167-177
• /
• 2011

Billions of barrels of briny produced water are generated in the United States every year during oil and gas production. The first step toward recovering or reusing this water is to remove the hazardous organics dissolved in the briny produced water. Biological degradation of hazardous volatile compound could be possible regardless of salinity if they were extracted from briny water. In the current work, the effectiveness of a vapor phase biofilter to degrade the gas-phase contaminants (benzene, toluene, ethylbenzene and xylenes, BTEX) extracted from briny produced water was evaluated. The performance of biofilter system responded well to short periods when the BTEX feed to the biofilter was discontinued. To challenge the system further, the biofilter was subjected to periodic spikes in inlet BTEX concentration as would be expected when it is coupled to a Surfactant-Modified Zeolite (SMZ) bed. Results of these experiments indicate that although the BTEX removal efficiency declined under these conditions, it stabilized at 75% overall removal even when the biofilter was provided with BTEX-contaminated air only 8 hours out of every 24 hours. Benzene removal was found to be the most sensitive to time varying loading conditions. A passive, granular activated carbon bed was effective at attenuating and normalizing the peak BTEX loadings during SMZ regeneration over a range of VOC loads. Field testing of a SMZ bed coupled with an activated carbon buffering/biofilter column verified that this system could be used to remove and ultimately biodegrade the dissolved BTEX constituents in briny produced water.