• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.977-983
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• 2005

The removal characteristics of ethyl acetate and 2-butanol were investigated in a bench-scale down-flow biofilter packed with Jeju scoria medium. Various inlet concentrations and gas flow rates were tested. The adaptation times of microorganisms to the change of the influent concentration of ethyl acetate and 2-butanol gas were found to be about 3 days. At the inlet concentration of 300 ppmv and empty bed contact time (EBCT) of 15 see, the removal efficiencies of the biofilter for ethyl acetate and 2-butanol were above $99.9\%$. The maximum removal capacity of the biofilter for ethyl acetate was $316-318\;g/m^3/h$ and that for 2-butanol was $245-251\;g/m^3/h$. Overall, the removal capacity of the biofilter for ethyl acetate was $50-70\;g/m^3/h$ larger than that for 2-butanol. During the operation of 65 days, the pressure drop through the biofilter column was maintained below $13\;mmH_{2}O/m$. Although the pH in the drain water decreased from 7.2 to 5.0, the pH drop did not affect the removal of the gases. From the above results, the biofilter using Jeju scoria as a packing material seemed to very effectively treat waste gases such as ethyl acetate and 2-butanol.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.3
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• pp.265-276
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• 2007

The primary objective of this study is to investigate the effect of media on the performance of biofilters. Two types of experiments were carried out in this study. The first type of experiment used a biofilter with the media composed of three different packing materials of compost, peatmoss and GAC(granular activated carbon), whereas the second type used a biofilter with the media composed of compost only. It was found from the two experiments that the biofilter composed of compost, peatmoss and GAC showed better performance than the one composed of compost only with the higher toluene removal efficiency, lower pressure drop, and more uniform media moisture content. In particular, no appreciable media compression occurred for the biofilter composed of compost, peatmoss and GAC, whereas significant media compression took place in the biofilter composed of compost only. As suggested by the other researchers, it is likely that GAC may be responsible for the higher toluene removal efficiency in the case of the biofilter composed of mixed media especially for the early stage of biofiltration due to its adsorption capability of toluene of such high concentration as 300 ppm. It was also regarded that GAC may playa major role in maintaining lower media pressure drop in the case of the mixed media than the media with compost only because of its mechanical strength resisting to the compression. Nonetheless, further refined experiments may need to draw more accurate conclusion. The results of the additional test run using the same mixed media showed that the biofilter system using the mixed media can be consistently operated for more than 100 days very stably despite sudden change in operating conditions of temperature and flow rate.

• Agricultural and Biosystems Engineering
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• v.3 no.2
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• pp.59-64
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• 2002

Odor generated during composting of livestock manure is mainly due to ammonia emission. Biofiltration is a desirable method to control composting odor. This study was conducted to analyze the efficiency of using fresh compost as a biofilter. A mixture of cattle manure and recycled compost was composted in a bin equipped with a suction-type blower. The exhaust gas was filtered through the fresh compost. Residence time was controlled by the flow rate of exhaust gas and the depth of filtering materials. At the aeration rate of 30 L/min(experiment I), ammonia reduction rate varied from 100% to -15% for biofilter A(residence time 56.5 s) and almost 100% for biofilter B(residence time 113 s). At the aeration rate of 30 L/min, the cumulative ammonia reduction rate was 80.5% for biofilter A and 99.9% for biofilter B. At the aeration rate of 50 L/min(experiment II), the lowest reduction rate showed a negative value of -350% on the 8th and 9th day for biofilter A(residence time 33.9 5), and 50% on the loth day for biofilter B(residence time 67.8s). At the aeration rate of 50 L/min, the cumulative ammonia reduction rate was 82.5% fur biofilter A and 97.4% for biofilter B. Filtering efficiency was influenced by residence time. The moisture content(MC) and total nitrogen(T-N) of the filtering material were increased by absorbing moisture and ammonia included in the exhaust gas, while pH was decreased and total carbon(T-C) remained unchanged during the filtering operation.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.669-675
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• 2005

Biological nitrate removal from groundwater was investigated in the biofilters packed with both gravel/sand and plastic media. Removal of particles and turbidity were also investigated in the 2-stage biofilter system consisted of biofilter and subsequent sand filter. In the single biofilter packed with gravel and sand, nitrate removal efficiency was dropped with the increase of filtration velocity and furthermore, nitrite concentration increased up to 3.2 mg-N/L at 60 m/day. Denitrification rate at the bottom layer below 25 cm was faster 8 times than upper layer in the up-flow biofilter. Nitrite build-up, due to the deficiency of organic electron donors, occurred at the upper layer of bed. Besides DO concentration and organic carbon, contact time in media was the main factor for nitrate removal in a biofilter. The most of the effluent particles from biofilter was in the range from 0.5 to $2.0{\mu}m$, which resulted in high turbidity of 1.8 NTU. However, sand filter followed by biofilter efficiently performed the removal of particles and turbidity, which could reduce the turbidity of final filtrate below 0.5 NTU. Influent nitrate was removed completely in the 2-stage biofilter and no nitrite was detected.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.3
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• pp.269-276
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• 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
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• v.11 no.12
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• pp.1327-1331
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• 2002

The cork have been preferred over the conventional materials, zeolite, ceramics, and lignite as a biofilter medium. During the 6 months of operation, the performance of the cork biofilter was considered good with 150ppm of mixture BTX vapor efficiencies greater than 90% at 60 second of EBCT. It was observed 56 % of removal efficiency under transition conditions at first stage, and then the removal efficiency was increased to above 90 %, and the sustainability of removal efficiency was maintained. At second stage, the performance of cork biofilter was not decreased 90 % efficiency with 150 ppm BTX at 30 sec. EBCT. The production of $CO_2$ due to microbial respiration was increased to the 40 % on the operation of cork biofilter.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.503-511
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• 2009

VOC mixture was fed to a trickle bed air biofilter (TBAB) with step-change in influent mixture concentrations from 50 ppmv to 1,000 ppmv, corresponding to loadings of $5.7\;g/m^3/hr$ to $114.1\;g/m^3/hr$. VOC mixture was an equimolar ratio of two aromatic VOCs, i.e., toluene and styrene, and two oxygenated VOCs, i.e., methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK). The TBAB system employed backwashing as biomass control. The experimental results showed that a critical loading rate for VOC mixture removal was determined to be about $60\;g/m^3/hr$, and critical loading rates for individual VOCs in the mixture were different. Specifically, toluene content in the mixture played a major role in the biofilter overall performance. As VOC mixture was fed beyond the critical loading rate, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing was delayed, which was a critical factor in the biofilter performance. In the mass balance analysis, 63.8% of the carbon equivalent in VOCs removal was used for $CO_2$ production during the experimental runs. The 82.6% nitrogen utilized in the biofilter was contributed to microbial cell synthesis. The obtained results were compared against consistently high efficient performance of TBAB for VOC mixture by employing backwashing as biomass control.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.7
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• pp.1209-1216
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• 2020

Objective: The present study aimed to evaluate the performance of odor abatement by using two different ventilation-biofilter systems with recycled stablized swine wastewater. Methods: The performance of odor removal efficiency was evaluated using two different ventilation-biofilter-recycled wastewater arrangements. A recirculating air-flow ventilation system connected to a vertical biofilter (M1) and a plug-flow ventilation system connected to a horizontal biofilter (M2) were installed. Water dripping over the surface of the biofilter was recycled at a flow rate of 0.83 L/h in summer and 0.58 L/h in winter to reduce odorous compounds and particulate matter (PM). The experiments were performed for 64 days with M1 and M2 to investigate how these two ventilation-biofilter systems influenced the reduction of odor compounds in the model houses. Odorous compounds, NH₃ and volatile organic compounds (VOCs) were analyzed, and microclimatic variables such as temperature, humidity, and PM were monitored. Results: Ammonia concentration inside M1 was about 41% higher on average than that in M2. PM and total suspended particles (TSPs) inside M1 were about 62.2% and 69.9%, respectively, higher than those in M2. TSPs in the model house were positively correlated with the concentration of NH₃ and VOCs. Conclusion: M2 emitted lower concentration of odorous compounds than M1. Moreover, M2 could maintain the optimum temperature condition for a swine house during the cooler season. The plug-flow ventilation-horizontal biofilter system could be used for pig houses to minimize air pollution produced by swine farming activities and maintain optimum microclimate conditions for pigs.

• Environmental Engineering Research
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• v.21 no.3
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• pp.311-317
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• 2016

A new type of biofilter packed with composite carriers was designed for tertiary denitrification of the secondary effluent with removal of both oxidized nitrogen and suspended solids (SS). At the empty bed residence time of 15 min and organic carbon to nitrate nitrogen ($C/NO_3-N$) ratios of 2, 1.5 and 1 g/g, the removal percentage of $NO_3-N$ was 67%, 58% and 36% in the ethanol biofilter, and was 61%, 43% and 26% in the acetate biofilter, respectively. The biofilters packed with composite carriers removed SS effectively, with the effluent turbidity in both biofilters of less than 3 NTU. During the operating cycle between the biofilter backwashings, the $NO_3-N$ removal percentage decreased initially after backwashing, and then gradually increased. Under $C/NO_3-N$ ratios of 2, 1.5 and 1 g/g, the $NO_3-N$ reduction rate was 1.75, 1.04 and $0.68g/m^2/d$ in the ethanol biofilter, and was 1.56, 1.07 and $0.76g/m^2/d$ in the acetate biofilter, respectively. In addition, during denitrification, the ratio of the consumed chemical oxygen demand to the removed $NO_3-N$ was 5.06-8.23 g/g in the ethanol biofilter, and was 4.26-8.6 g/g in the acetate biofilter.

• Journal of Environmental Health Sciences
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• v.40 no.2
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• pp.127-136
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• 2014

Objectives: This study was conducted to investigate the removal of high odor concentration from swine wastewater treatment facility by full scale biofilter using liquid with deodorant mixed with earthworm cast and distillery sludge. Methods: The supply of the culture liquid to the microorganism on the media in the biofilter increases the activity and growth of biomass. The experimental equipment was biofilter tower with treatment capacity of 90 m 3/min. The experimental conditions included gas flow of $60m^3/min$, retention time of 20 sec, and gas/liquid ratio of 67. Results: With changing season from winter to summer, the inlet odor concentration of ammonia increased from 2.5 ppm to 29 ppm, and of hydrogen sulfide from 21 ppm to 91 ppm, respectively. The odor treatment system with biofilter using the culture liquid was stable when the high loading rate increased and showed excellent removal grade with an average of 96.7% for ammonia, and an average of 93.7% for hydrogen sulfide. The pH and SCOD in the recirculating culture liquid near the bottom of the biofilter tower decreased with operation time, but its influence on the odor removal rate was negligible, because the organic matter (SCOD) was replaced by some culture liquid supplied 2-4 times per day. Conclusions: The biofilter using culture liquid could successfully remove high odor concentration which was generated from swine wastewater treatment facility.