• 한국지하수토양환경학회지:지하수토양환경
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• 제19권6호
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• pp.72-79
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• 2014

Cavitation generated by ultrasonic irradiation can enhance the diffusional transport of organic contaminants from soil surfaces or pores. Therefore, ultrasound soil washing can be an alternative of traditional soil washing process. In this study, soil was artificially contaminated with n-tetradecane, n-hexadecane and phenanthrene. A plate type ultrasonic reactor at 25 kHz frequency and 1000W power was used for laboratory soil washing experiments. Ultrasonic soil washing efficiency was compared with those of traditional soil washing using mechanical mixing. Various operational parameter such as soil/liquid ratio, irradiation time, particle size, and soil organic matter content was tested to find out the optimum condition. It was found that ultrasonic soil washing demonstrates better performance than mechanical soil washing. Optimum soil:liquid ratio for ultrasonic soil washing was 1 : 5. Desorption of organic contaminants from soils by ultrasonic irradiation was relatively fast and reached equilibrium within 10 minute. However, decrease in the soil particle sizes by ultrasonic irradiation results in re-adsorption of contaminants to soil phase. It was also observed that soil particle size distribution and soil organic matter content have significant effects on the efficiency of ultrasonic soil washing.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.462-466
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• 2003

This study was conducted to examine the potential of biosparging process in removing diesel contaminated soil and groundwater. The experiment was carried out lab-scale biosparging reactor and the biodegradation rate of diesel was evaluated as function of air injection rate and pattern. When renter was operated as air injection rate of 1000$m\ell$/min and pulsed air injection(15min pulse, 15min downtime), DO concentration in the renter was higher than another operating condition. The evidence for biodegradation of diesel was the $O_2$ utilization and $CO_2$ product following the cessation of sparging. Especially, air injection rate of 2000$m\ell$/min and pulsed air injection(15min pulse, 15min downtime) enhanced the diesel biodegradation during the operating. After 120day, the biodegradation rate of diesel was decreased as the lack of carbon source.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.310-313
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• 2003

Removal of phenanthrene by electrokinetic method combined with Fenton-like process was studied in a model system. The scale of reactor was 120 cm in length, 10 cm in width, and 50 cm in height. Sand was selected as a model soil. Bentonite was filled in the space between reservoir and contaminated soil to control the flow rate of water. When constant voltage of 100 V was applied to this system, current varied from 1000 mA to 290 mA for 28 days. pH of anode and cathode reservoirs became to 2 and 13, respectively. Removal efficiency of phenanthrene was more than 60 %.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.83-95
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• 2004

The removal efficiency of several washing agents on the $Cs^+$ ion was investigated. Leaching of $Cs^+$ ion from the soil surface by washing agents is affected by the exchange capability of the washing solution. Reuse tests of the effective soil washing agents such as $BaCl_2$, NaOH, citric acid＋ $HNO_3$ and oxalic acid were performed. NaOH, citric acid ＋ $HNO_3$ and oxalic acid solutions can be reused after passing through the ion exchange column. Among the tested solutions, both of citric acid＋ $HNO_3$ and oxalic acid were effective for the decontamination of TRIGA research reactor soil. The radioactivity of soils can be reduced to a release level by the successive application.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권5호
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• pp.49-55
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• 2012

A 1.28 L-batch reactor and continuous-flow stirred tank reactor (CFSTR) fed with formate and trichloroethene (TCE) were operated for 120 days and 56 days, respectively, to study the effect of formate as electron donor on anaerobic reductive dechlorination (ARD) of TCE to cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene (ETH). In batch reactor, injected 60 ${\mu}mol$ TCE was completely degraded in the presence of 20% hydrogen gas ($H_2$) in less than 8 days by anaerobic dechlorination mixed-culture (300 mg-soluble protein), Evanite Culture with ability to completely degrade tetrachloroethene (PCE) and -TCE to ETH under anaerobic conditions. Once the formate was used as electron donor instead of hydrogen gas in batch or chemostat system, the TCE-dechlorination rate decreased and acetate production rate increased. It indicates that the concentration of hydrogen produced in both systems is possibly more close to threshold for homoacetogenesis process. Soluble protein concentration of Evanite culture during the batch test increased from 300 mg to 688 mg for 120 days. Through the protein monitoring, we confirmed an increase of microbial population during the reactor operation. In CFSTR test, TCE was fed continuously at 9.9 ppm (75.38 ${\mu}mol/L$) and the influent formate feed concentration increased stepwise from 1.3 mmol/L to 14.3 mmol/L. Injected TCE was accumulated at 18 days of HRT, but TCE was completely degraded at 36 days of HRT without accumulation of the injected-TCE during the left of experiment period, getting $H_2$ from fermentative hydrogen production of injected formate. Although c-DCE was also accumulated for 23 days after beginning of CFSTR operation, it reached steady-state in the presence of excessive formate. We also evaluated microbial dynamic of the culture at different chemical state in the reactor by DGGE (denaturing gradient gel electrophoresis).

• Journal of the Korean Wood Science and Technology
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• 제31권6호
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• pp.73-82
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• 2003

Various forest humic substances were collected at different climate regions with different forest types, and adsorption of heavy metals such as Cu(II), Zn(II), Cd(II) and Cr(III) were characteristically conducted to obtain optimal adsorption conditions and to evaluate the removal efficiency of heavy metals by each forest humic substance. The adsorption isotherms for Cu(II), Zn(II), Cd(II) and Cr(III) conformed to Langmuir's equation. In the stirred reactor, the removal efficiencies of Cu(II), Zn(II) and Cd(II) by forest humic substances were more than 90% but that of Cr(III) was less than 60%. The adsorption capacities of heavy metals in the stirred reactor were considerably varied depending on the type of forest humic substances. Among humic substances, the one from deciduous forest at subtropical region showed the highest removal efficiency for Cu(II). There was no significant difference in removal efficiency by each heavy metal depending on reaction temperature ranged from 20 to 50oC except for Cr(III), and the adsorptions of Cu(II), Zn(II) and Cd(II) were occurred rapidly in the incipient stage within 10 min, while Cr(III) needed more reaction time to be adsorbed. The stirred and packed bed column reactors showed similar adsorption characteristics of heavy metals by humic substances, but the removal efficiency was considerably higher in the packed bed column reactor than in the stirred reactor. Therefore, in actual operation process, a continuous packed bed column reactor was more economical.

• 환경위생공학
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• 제15권2호
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• pp.75-84
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• 2000

운전 온도 $35^{\circ}C$, 평균 유기물부하 $3.1{\;}kgCOD/m^3/day$ 및 수리학적체류시간 10일에서 혐기성 연속회분식공정에 의한 분뇨처리를 수행하였다. 공정의 평가는 대조 소화조로 완전혼합형의 소화조와 병행하여 수행되었다. 본 실험에서 분뇨는 고농도의 암모니아성 질소와 침전성 고형물을 함유하고 있음에도 불구하고 희석 없이 소화가 가능하였다. 혐기성 연속회분식공정에서 고형물은 급속하게 증가하여 완전혼합형의 대조 소화조에 비하여 소화조내 고형물(biomass)의 농도가 2.4배로 증가하였고, 가스발생량에 있어서도 대조 소화조에 비해 현격한 증가를 보였으며 그 증가율은 205~220%에 달했다. 부가적인 침전 시설이 없이도 혐기성 연속회분식공정의 유출수질이 대조 소화조 보다 높게 나타났는데 상징액 기준으로 휘발성고형물 제거율은 혐기성 연속회분식공정이 대조 소화조 보다 12~14% 높았다. 한편, 혐기성 연속회분식공정의 운전인자로 반응/침강비(R/T ratio)를 조사한 결과 R/T비가 1인 경우가 3의 경우보다 가스발생량, 메탄함량 및 유기물 제거율이 약간 높았으나 큰 차이는 없었다. 위의 실험결과들로부터 혐기성 연속회분식공정은 고농도의 암모니아성 질소와 침전성 유기물을 함유하고 있는 분뇨의 처리에 효과적이고 안정적인 공정으로 판단된다.

• 한국환경농학회지
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• 제19권2호
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• pp.177-182
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• 2000

토양 미생물을 이용한 고농도 축산폐수의 과부하 처리를 위한 공정개발 연구결과 유기물 제거율은 99%이었다. 상온 혐기조에서 $0.7kg\;BOD/m^3/d$ 이하에서 처리수의 BOD 농도는 150mg/L 이하를 이었다. 상온 혐기조를 운전한 실험에서 후속 폭기조의 물질 대사계수(km)는 $0.73hr^{-1}$, 세포증식계수(Y)는 0.433 g/VSS/g BODrm/d 였으며 중온으로 운전한 경우 후속 폭기조에서 각각 $1.45hr^{-1}$과 0.776 g VSS/g BODrm/d 로 반응계수 값이 두 배에 가깝게 개선되었다.

• 한국토양비료학회지
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• 제50권5호
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• pp.489-496
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• 2017

This study was conducted to test the applicability of hydroxy radical reactor system, which applied advanced oxidation processes, to sterilize pathogenic bacteria for nutrient solution recycling in closed hydroponics. Removal efficiency was tested on 25 L of nutrient solution maxed with 10 mL culture solution of bacteria, E. coli, and R. solanacearum in a pilot tank. The testing conditions included various levels of hydroxy radicals resulting from air flow rates of 40, 80, and $120L\;min^{-1}$, and 12 hours processing time. The removal of bacteria, E. coli, and R. solanacearum by hydroxy radical in nutrient solution was significantly increased with an increase in the flow rate of the air from $40L\;min^{-1}$ to $120L\;min^{-1}$. The optimum removal efficiency was achieved at an air flow rate of $120L\;min^{-1}$ for 2 hours treatment. There were no significant differences in removal efficiency among bacteria, E. coli, and R. solanacearum for tested level and time of hydroxy radical. These results verified the efficiency of hydroxy radical in removing the pathogenic bacteria and the applicability of hydroxy radical reactor system in the field.

• 상하수도학회지
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• 제13권1호
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• pp.43-50
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• 1999

In spite of low energy requirement, and operation and construction cost, biofilters with soil beds have not been operated efficiently. Because of excess moisture in winter and rainy periods, saturated pores in the bed prevent passage and sorption of odorous compounds. Sometimes this results in septic conditions that release previously sorbed and oxidized sulfur. Therefore, an economical and effective alternative needs to be developed. The objectives of this study were to confirm applicability of the granular scrap tires with compost for treating odorous gas as well as to obtain optimum design parameters for proposed system. In lab-scaled test, multiple stage reactors had lower headloss than a single stage reactor and less headloss was occurred for the gas with higher moisture content. For practical purpose, pilot-scaled reactor was operated to remove odor from septic tank, manure and animal wastewater treatment plant and composting machine. According to the results of pilot scaled test, $H_2S$ can be always removed completely and ammonia/amine can be removed excellently when proper moisture content is provided. The results from lab and pilot test showed that granular scrap tire could be replaced with soil as supporting material for biofilter showed excellent drainage because of its ability to reject moisture.