• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.789-800
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• 2013

$N_2O$ and $CH_4$, Greenhouse gas emission, Forest soil, Closed chamber technique, Soil uptake $N_2O$ and $CH_4$ are important greenhouse gases (GHG) along with $CO_2$ influencing greatly on climate change. Their soil emission rates are highly affected by bio-geo-chemical processes in C and N through the land-atmosphere interface. The forest ecosystems are generally considered to be net emission for $N_2O$; however, net sinks for $CH_4$ by soil uptake. Soil $N_2O$ and $CH_4$ emissions were measured at Mt. Taewha in Gwangju, Kyeonggi, Korea. Closed chamber technique was used for surface gas emissions from forest soil during period from May to October 2012. Gas emission measurement was conducted mostly on daytime (from 09:00 to 18:00 LST) during field experiment period (total 25 days). The gas samples collected from chamber for $N_2O$ and $CH_4$ were analyzed by gas chromatography. Soil parameters were also measured at the sampling plot. GHG averages emissions during the experimental period were $3.11{\pm}16.26{\mu}g m^{-2}hr^{-1}$ for $N_2O$, $-1.36{\pm}11.3{\mu}gm^{-2}hr^{-1}$ for $CH_4$, respectively. The results indicated that forest soil acted as a source of $N_2O$, while it acted like a sink of $CH_4$ on average. On monthly base, means of $N_2O$ and $CH_4$ flux during May (spring) were $8.38{\pm}48.7{\mu}gm^{-2}hr^{-1}$, and $-3.21{\pm}31.39{\mu}gm^{-2}hr^{-1}$, respectively. During August (summer) both GHG emissions were found to be positive (averages of $2.45{\pm}20.11{\mu}gm^{-2}hr^{-1}$ for $N_2O$ and $1.36{\pm}9.09{\mu}gm^{-2}hr^{-1}$ for $CH_4$); which they were generally released from soil. During September (fall) $N_2O$ and $CH_4$ soil uptakes were observed and their means were $-1.35{\pm}12.78{\mu}gm^{-2}hr^{-1}$ and $-2.56{\pm}11.73{\mu}gm^{-2}hr^{-1}$, respectively. $N_2O$ emission was relatively higher in spring rather than other seasons. This could be due to dry soil condition during spring experimental period. It seems that soil moisture and temperature mostly influence gas production and consumption, and then emission rate in subsoil environment. Other soil parameters like soil pH and chemical composition were also discussed with respect to GHG emissions.

• Journal of the Korean Institute of Gas
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• v.21 no.1
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• pp.72-79
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• 2017

The operating temperature range of the natural gas pipeline in Arctic environment would be controlled primarily to optimize gas throughput and to minimize the environmental impact resulting from operation of such pipelines. The temperature of the gas as it flows through the pipeline is a function of both the Joule-Thomson effect and the pipe to soil heat transfer. Therefore, the heat transfer and Joule-Thomson effect of the buried natural gas pipeline in this study were carefully considered. Soil temperatures and overall heat transfer coefficients were assumed to be $0{\sim}-20^{\circ}C$ and $0{\sim}5.5W/m^2K$, respectively. The gas temperature and pressure calculations along a pipeline were performed simultaneously at different soil temperatures and overall heat transfer coefficients. Also, this study predicted the phase change and hydrate formation for different soil temperatures and overall heat transfer coefficients using HYSYS simulation package.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.651-657
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• 2009

Shifts in the activity and diversity of microbes involved in aliphatic and aromatic hydrocarbon degradation in contaminated soil were investigated. Subsurface soil was collected from a gas station that had been abandoned since 1995 owing to ground subsidence. The total petroleum hydrocarbon content of the sample was approximately 2,100 mg/kg, and that of the soil below a gas pump was over 23,000 mg/kg. Enrichment cultures were grown in mineral medium that contained hexadecane (H) or naphthalene (N) at a concentration of 200 mg/l. In the Henrichment culture, a real-time PCR assay revealed that the 16S rRNA gene copy number increased from $1.2{\times}10^5$to $8.6{\times}10^6$with no lag phase, representing an approximately 70-fold increase. In the N-enrichment culture, the 16S rRNA copy number increased about 13-fold after 48 h, from $6.3{\times}10^4$to $8.3{\times}10^5$. Microbial communities in the enrichment cultures were studied by denaturing gradient gel electrophoresis and by analysis of 16S rRNA gene libraries. Before the addition of hydrocarbons, the gas station soil contained primarily Alpha- and Gammaproteobacteria. During growth in the H-enrichment culture, the contribution of Bacteriodetes to the microbial community increased significantly. On the other hand, during N-enrichment, the Betaproteobacteria population increased conspicuously. These results suggest that specific phylotypes of bacteria were associated with the degradation of each hydrocarbon.

• Geotechnical Engineering
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• v.5 no.4
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• pp.47-60
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• 1989

Soft offshore sediments quite frequently contain undissolved gas, probably methane pro- duced biogenically. The presence of gas bubbles can have a significant effect on the engineering behaviours of the seabed. One of the main difference between saturated and gassy soils is that the undrained response is not incompressible, and without volume change, may be assumed for a fully saturated soil. This paper describes the basic experimental work to further understanding of a gassy soil. The test has been performed for a gassy soil under undrained and drained conditions. It was confirmed that the gas inclusions deformed due to changes in the total stress on the sample and also the pore gas pressure response to change in total stress. but not directly to those in pore water pressure. And the test which applied the repeated load under undrained state also showed the similar behaviour as the simple load.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.81-82
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• 2005

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.978-980
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• 2010

This study was conducted to observe the cause of injury of fig plant. Nitrogen dioxide gas can be evolved at low pH or reduced in soil. Fig plant cultivated with nutrient solution was wilted or withered. Injury symptom for nutrient solution containing nitrous acid was worse as pH of soil decreased. However, increase in pH of nutrient solution treated with increasing $Ca(OH)_2$ solution prevented nutrient solution from producing nitrogen dioxide gas. Recovery of the fig plant by pH increase indicated that the cause of injury was nitrogen dioxide gas.

• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.63-72
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• 1997

This study presents a surveying of methane and carbon dioxide at sanitary landfills. The following results are obtained. (1) The majority of methane and the half of carbon dioxide pour out from vertical gas vents. (2) The quantity of carbon dioxide in cove. soil was greater than methane. (3) Even though gas extrusion in side slop area was small, the quantity of gas extrusion in side slop area was much greater than in coversoil area as especially carbon dioxide rate. (4) As were carried raw refuse layer, methane extrusion was trace, but carbon dioxide was large. (5) Gas extrusion quantity were changed by the compaction of soil, and the operating area of refuse. (6) Carbon dioxide portioned much larger in the whole landfill, but methane portioned much larger in gas vent and coversoil.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.25-33
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• 1999

The recent emergence of biofiltration as a cost effective waste-gas control technology has stimulated in European countries and the USA. Biofiltration of soil vapor extraction off-gas from gasoline contaminated site was simulated in lab-scale in this study. A filling material used was a compost. This study was conducted to evaluate biofiltration characteristics of the compost material for gasoline off-gas. TPH elimination capacity at the gas loading rate of about 50g/$\textrm{m}^3$((filling material)/hr was circa 40g/$\textrm{m}^3$((filling material)/hr. Removal rate of xylene was the highest among BTEX. while it was the lowest in case of bezene. The maximum elimination capacity of the compost was about 1.5g/$\textrm{m}^3$((filling material)/hr for benzene. More than 95% of trimethylbenzene and naphtalene were removed below the loading rate of 0.7g/㎥(filling material)/hr. About 80% of total TPH and BTEX were removed by biodegradation.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1325-1335
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• 2007

The utility of soil-gas surveys is directly proportional to their accuracy in reflecting and representing changes in the subsurface concentrations of source compounds. Passive soil-gas vapor-phase is merely a fractional trace of the source, so, as a matter of convenience, the units used in reporting detection values from EMFLUX surveys are smaller than those employed for source-compound concentrations. According to the Leaking Underground Storage Tank(LUST) Program Annual Report, approximately 16 U.S. million dollars were spent for environmental site investigations at over 1,600 Underground Storage Tank(UST) sites and approximately over 1,000 acres of land was characterized and remediated in the State of Illinois in the year of 2003 alone. The main purpose of this study is to propose an idea to significantly reduce the site investigation cost by utilizing a passive soil-gas survey and conventional intrusive drilling method and to fully define the three dimensional characteristics of subsurface contamination from two industrial drycleaning facilities.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.1
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• pp.67-76
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• 2007

Bioventing is commonly used for petroleum hydrocarbon (PHC) spills. This process provides better subsurface oxygenation, thus stimulating degradation by indigenous microorganisms. Therefore soil vapor monitoring points (VMPs) are extremely important in determining the potential effectiveness of bioventing and in long-term monitoring of bioventing progress. In this study in-situ soil gas monitoring well (GMW) was developed and presented the pilot test results which recover the contaminated site by bioventing method. The result of application was successful and it was expected that GMW developed could be applied to the evaluation procedure of bioventing effectiveness and long-term remediation potential.