• Environmental Engineering Research
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• v.24 no.3
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• pp.389-396
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• 2019

The electrical energy consumption (EEC) in removal of NO by a $UV/H_2O_2$ oxidation process was introduced and related to removal efficiency of this gas. The absorption-reaction of NO was conducted in a bubble column reactor in the presence of $SO_2$. The variation in NO removal efficiency was investigated for various process parameters including NO and $SO_2$ inlet concentrations, initial concentration of $H_2O_2$ solution and gas flow rate. EEC values were obtained in these different conditions. The removal efficiency was increased from about 22% to 54.7% when $H_2O_2$ concentration increased from 0.1 to 1.5 M, while EEC decreased by about 70%. However, further increase in $H_2O_2$ concentration, from 1.5 to 2, had no significant effect on NO absorption and EEC. An increase in NO inlet concentration, from 200 to 500 ppm, decreased its removal efficiency by about 10%. However, EEC increased from $2.9{\times}10^{-2}$ to $3.9{\times}10^{-2}kWh/m^3$. Results also revealed that the presence of $SO_2$ had negative effect on NO removal percentage and EEC values. Some experiments were conducted to investigate the effect of $H_2O_2$ solution pH. The changing of pH of oxidation-absorption medium in the ranges between 3 to 10, had positive and negative effects on removal efficiency depending on pH value.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.6
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• pp.599-606
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• 1998

Removal of toluene vapor from airstreams was studied in a biological reactor known as a biofilter. The biofilter was packed porous ceramic inoculated with thickened activated sludge (MLVSS 17,683 mg/L). The lab-scale biofilter was operated for 42 days under various experimental conditions including inlet toluene concentrations and flow rates of the contaminated air streams. Removal efficiency reached up 96.6% after 4 days from start up. Nutrient limitation was proposed as a reason for the decrease in biofilter performence. Biofilter performance decreased substantially, coincident with the buildup of back pressure due to accumulation of excess VSS within the medium bed. Practically, the bed needs to be backwashed when the overall pressure drop is greater than 460.6 Pa at SV (Space Velocity) 100 h-1. Periodic backwashing of the biofilter was necessary for removing excess biomass and attaining stable long -term high removal efficiency The removal efficiency of toluene in the biofilter decreased as the gas velocity and toluene concentration in the inlet gas increased. The maximum elimination capacity of ceramic biofilter could reach up to 444.85 g/m3. hr. When the loading of toluene exceed this critical value, substrate inhibition occurred.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.127-132
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• 1997

The characteristics of the ozone treatments of phenol were studied in a laboratory scale wastewater treatment system. The ozone treatment of wastewater was carried out in a batch-type reactor. The initial pH of wastewater(7-10), volumetric flow rate(1-2l/min) and ozone concentration(20~30 mg/l) of aerating gas were considereal as experimental variables in the ozone treatment. Phenol was decomposed easily by the ozone in a batch treatment, where the rate determining step was the COD removal that is decomposition of intermediates formed by the ozonation of phenol. Phenol decomposition and COD removal could be expressed by the first order reaction for the phenol concentration and COD, respectively. Rate constants of phenol decomposition and COD removal increased with the initial pH, volumetric flow rate and ozone concentration of aeration gas. Under the present experimental condition, their relationships could be given by for the phenol decomposition $k'=4.46\times 10^{-9}[pH]_o ^{3.94}[O_3]^{1.42}Q_{O3}^{1.57}$ for the COD removal $k=2.46\times 10^{-10}[pH]_o ^{5.19}[O_3]^{1.15}Q_{O3}^{1.19}$

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.21-27
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• 2005

This study was conducted to evaluate the biofiltration treatment characteristic for benzene vapor gas. Compost and calcium silicate porous material were used as biofilter fillers. Gas velocity and empty bed retention time were 15 m/hr and 4 min, respectively. Benzene gas removal efficiency of P-Bio (calcium silicate porous material with inoculation) was the highest and maintained in over 98%. After shock input of benzene gas, the removal efficiency of P-Bio biofilter was recovered within 2 days, while 5 days were taken in CP-Bio (compost + calcium silicate porous material mixture with inoculation) and CP (compost + calcium silicate porous material mixture without inoculation) biofilters. The removal efficiency of P-Bio biofilter was near 100% in the loading rate of <$85g/m^3$(filling material)/hr, It was shown that the maximum elimination capacities of P-Bio, CP-Bio, and CP biofilters were 95, 69, and $66\;g/m^3$(filling material)/hr, respectively. Microbial number of P-Bio, which the number was the lowest at start-up, was 3 orders increased on operational day 48. $CO_2$ was generated greatly in order of P-Bio, CP-Bio, and CP biofilters.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.93-101
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• 2011

The modeling of SDR was carried out for the application of the solid waste incineration system. To find optimum operating condition for removal of acidic gases, computation fluid dynamic(CFD) model was used. In this study, the temperature profile of SDR(spray dry reactor) and the gas velocity profile for different models were investigated. In this model, the diameter of SDR was 3 meter and the height of SDR was 9 meter. The amount of inlet combustion gas of SDR was $6,125Nm^3/hr$ and the inlet temperature of SDR was 493 K. The amount of lime injection of SDR was 151 kg/hr. When the inlet shape of SDR was changed, the temperatur of SDR was changed and the gas velocity of SDR was 0.48 m/sec to 1.17m/sec and the outlet gas velocity of SDR was 6.9 m/sec to 7.42m/sec As a result of modeling, the average velocities in SDR and outlet were 0.489 m/sec and 7.424 m/sec, respectively, in which the temperature of outlet in SDR was 448 K.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.128-134
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• 2012

The pilot scale experiments can handle the flue gas up to 1,000 $Nm^3/hr$ for separation of carbon dioxide included in real flue gas at coal-fired power plant. The operational characteristics was analyzed with the main experimental variables such as flue gas flow rate, absorbent circulation rate using chemical absorbents mono-ethanolamine( MEA) and 2-amino-2-methyl-1-propanol(AMP). The more flue gas flow rate decreased in 100 $m^3/hr$ in the MEA 20 wt% experiments, the more carbon dioxide removal efficiency was increased 6.7% on average. Carbon dioxide removal efficiency was increased approximately 2.8% according to raise of the 1,000 kg/hr absorbent circulation rate. It also was more than 90% at $110^{\circ}C$ of re-boiler temperature. Carbon dioxide removal efficiency of the MEA was higher than that of the AMP. In the MEA(20 wt%) experiment, carbon dioxide removal efficiency(85.5%) was 10% higher than result(75.5%) of ASPEN plus simulation.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.4
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• pp.387-394
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• 2011

A study on the removal of sulfur dioxide and nitrogen oxide was carried out using a non-thermal nano-pulse corona discharger at different gas temperatures. Pulse voltage with a high voltage of 50 kV, a pulse rising time of about 100 ns, a full width at half maximum of about 500 ns and a frequency of 1 kHz was applied to a wire-cylinder corona reactor. Ammonia and propylene gases were added into the corona reactor as additives with a static mixer. Ammonia addition had less effect on $SO_2$ reduction at the higher temperature because of the retardation of ammonium sulfate formation. However, propylene addition enhanced NO reduction at higher temperature due to increased gas mixture. $SO_2$ was further removed at the mixed $SO_2$ and NO gas due to increased $NO_2$ by the conversion of NO. The addition of ammonia and propylene gases was more highly dominant for the removal of sulfur dioxide compared to the sole pulse corona without the additives. However, the specific energy density per unit concentration of pulse corona as well as propylene additive was an important factor to remove NO gas. Therefore, the specific energy density per unit concentration of 0.04 Wh/($m^3{\cdot}ppm$) was necessary for the NO removal of more than 80% with the concentration ratio of 2.0 for propylene and NO. Hydrogen peroxide was another alternative additive to remove both $SO_2$ and NO in the nano-pulse corona discharger.

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

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.649-658
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• 2012

In this study, the influencing factors for efficient anaerobic digestion of high strength ammonia-nitrogen wastewater removal were investigated by testing biochemical methane potential test. In the influencing factors, the trace metals which could increase activity of anaerobic microorganisms, microbial concentration and types were evaluated. In the results, trace metals supplementation showed gas production amount higher than those without addition of trace metals. Among the tested trace metals, B, Ni, and Se were preferable to gas production. In the result of gas production according to the microbial concentration, the amount of gas production was proportional to the microbial concentration. In addition, the shortest lag time and the fastest gas production rate were achieved when the highest microbial concentration was tested. granule-type microorganism produced more gas than suspended-type microorganism. In conclusion, the efficient anaerobic digestion for high strength ammonia-nitrogen wastewater removal could be achieved by applying necessary trace metals injection and high concentration granule type microorganism.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1309-1313
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• 2003

This study was carried out to obtain the optimal ammonia removal efficiency using pyroligenous liquid for the economical and environment-friendly odor removal at a petty livestock farmhouse. The ammonia removal efficiencies were evaluated due to changing dilution rates(${\times}$10, ${\times}$20, ${\times}$30, ${\times}$50 and ${\times}$100 times) and different spray amounts(10$m\ell$ and 20$m\ell$) of pyroligenous liquid. The wet scrubber device was used to remove odor in closed-type livestock farmhouse. According to dilution rate of the pyroligenous liquid, the optimum rate was 20 times and the removal efficiency increased by decreasing dilution rates. In the case of spray amounts with the optimum dilution, the amount was 20 me and the removal efficiency increased by increasing spray amount. Also, the removal efficiency by using wet deodorizing device was 83.0-97.0％ with 20 times diluted liquid.