• 한국기후변화학회지
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• 제7권2호
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• pp.103-110
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• 2016

In this study, we researched the characteristics of $CH_4$ and $N_2O$ emission of the wastewater treatment (WWT) process in the dairy industry. For flux measurements at the air-water interface, a floating dynamic flow-through chamber was used above the water surface. $CH_4$ and $N_2O$ concentration from the WWT process was measured by NDIR (Non-Dispersive Infrared) Analyser. In the study, $CH_4$ and $N_2O$ fluxes results showed a distinct difference for each WWT process. 60% of the GHG emissions which was the highest percentage were from the equalization tank. Reactor tank was second with 27% of the total emissions from the WWT. Aeration tank was third with 12% of the total emissions. The tendency was that the more the wastewater was treated, the less GHGs were emitted. $CH_4$ and $N_2O$ showed the same tendency. This indicates that the concentrations and properties of wastewater could affect the tendency.

• 한국대기환경학회지
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• 제16권5호
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• pp.499-509
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• 2000

Next to carbon dioxide, methane is the second largest contributor to global warming among anthropogenic greenhouse gases. Methane is emitted into the atmosphere from both natural and anthropogenic sources. Natural sources include wetlands, termites, wildries, ocean and freshwater. Anthropogenic sources include landfill, natural gas and oil production, and agriculture. These manmade sources account for about 70% of total global methane emissions; and among these, landfill accounts for approximately 10% of total manmade emissions. Solid waste landfills produce methane as bacteria decompose organic wastes under anaerobic conditions. Methane accounts for approximately 45 to 50 percent of landfill gas, while carbon dioxide and small quantities of other gases comprise the remaining to 50 to 55 percent. Using the closed enclosure technique, surface emission fluxes of methane from the selected landfill sites were measured. These data were used to estimate national methane emission rate from domestic landfills. During the three different periods, flux experiments were conducted at the sites from June 30 through December 26, 1999. The chamber technique employed for these experiments was validated in situ. Samples were collected directly by on-site flux chamber and analyzed for the variation of methane concentration by gas chromatography equipped with FID. Surface emission rates of methane were found out to vary with space and time. Significant seasonal variation was observed during the experimental period. Methane emission rates were estimated to be 64.5$\pm$54.5mgCH$_4$/$m^2$/hr from Kimpo landifll site. 357.4$\pm$68.9mgCH$_4$/$m^2$/hr and 8.1$\pm$12.4mgCH$_4$/$m^2$/hr at KwanJu(managed and unmanaged), 472.7$\pm$1056mgCH$_4$/$m^2$/hr at JonJu, and 482.4$\pm$1140 mgCH$_4$/$m^2$/hr at KunSan. These measurement data were used for the extrapolation of national methane emission rate based on 1997 national solid waste data. The results were compared to those derived by theoretical first decay model suggested by IPCC guidelines.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2010년도 춘계학술대회 논문집
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• pp.263-264
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• 2010

• 한국대기환경학회지
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• 제29권2호
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• pp.171-185
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• 2013

Wetland has been known as a major biogenic source of $CH_4$ in globe. In a global scale, the amounts of 55~150 Tg $CH_4$ are released into the atmosphere annually from wetlands; and it accounts for about 21% of total $CH_4$ annual global emission. From August 2010 to August 2011, measurements of major greenhouse gas ($CO_2$, $CH_4$, $N_2O$) emissions were conducted from a freshwater wetland at Kunsan ($35^{\circ}56^{\prime}38.94^{\prime\prime}N$, $126^{\circ}43^{\prime}16.62^{\prime\prime}E$), Korea by using floating closed static chamber method. Flux measurements for these gases from western coastal tidal flat at Seocheon ($36^{\circ}07^{\prime}13.85^{\prime\prime}N$, $126^{\circ}35^{\prime}43.18^{\prime\prime}E$), Korea were managed from July 2011 to February 2012 by using closed static chamber method. The average gas fluxes and ranges from freshwater wetland experiment were $0.155{\pm}0.29\;mg\;m^{-2}\;hr^{-1}$ (-0.054~0.942 $mg\;m^{-2}\;hr^{-1}$) for $CH_4$, $17.30{\pm}73.27\;mg\;m^{-2}\;hr^{-1}$ (-52.44~261.66 $mg\;m^{-2}\;hr^{-1}$) for $CO_2$, and $0.004{\pm}0.01\;mg\;m^{-2}\;hr^{-1}$ (-0.02~0.07 $mg\;m^{-2}\;hr^{-1}$) for $N_2O$, respectively. Monthly base flux measurement results revealed that $CH_4$ fluxes during summer months in high water temperature were significantly high, and at least order of one higher than those during other months. The average fluxes and ranges of these greenhouse gases from tidal flat during the experimental period were $0.002{\pm}0.08\;mg\;m^{-2}\;hr^{-1}$ (-0.16~0.22 $mg\;m^{-2}\;hr^{-1}$) for $CH_4$, $-31.18{\pm}75.33\;mg\;m^{-2}\;hr^{-1}$ (-298.87~101.93 $mg\;m^{-2}\;hr^{-1}$) for $CO_2$, and $0.001{\pm}0.01\;mg\;m^{-2}\;hr^{-1}$ (-0.017~0.03 $mg\;m^{-2}\;hr^{-1}$) for $N_2O$, respectively. Comparing the results of gas emissions from tidal flat to those from freshwater wetland, we found significantly lower emissions from tidal flat based on the experiment. Physicochemical parameters of water and soil at these experimental plots were also sampled and analyzed for understanding their correlation with these gas emissions.

• 한국대기환경학회지
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• 제29권6호
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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.

• 한국환경농학회지
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• 제26권2호
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• pp.131-140
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• 2007

Phospho-gypsum a primary waste by-product in phosphate fertilizer manufacturing industry and a potential source of electron acceptors, such as mainly of sulfate and a trace amount of iron and manganese oxides, was selected as soil amendment for reducing methane $(CH_4)$ emissions during rice cultivation. The selected amendment was added into potted soils at the rate of 0, 2, 10, and 20 Mg $ha^{-1}$ before rice transplanting. $CH_4$ flux from the potted soil with rice plant was measured along with soil Eh and floodwater pH during the rice cultivation period. $CH_4$ emission rates measured by closed chamber method decreased with increasing levels of phospho-gypsum application, but rice yield markedly increased up to 10 Mg $ha^{-1}$ of the amendment. At this amendment level, total $CH_4$ emissions were reduced by 24% along with 15% rice grain yield increment over the control. The decrease in total $CH_4$ emission may be attributed due to shifting of electron flow from methanogenesis to sulfate reduction under anaerobic soil conditions.

• 한국대기환경학회지
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• 제23권2호
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• pp.225-241
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• 2007

A closed flux chamber system was used for measuring major greenhouse gas (GHG) emission from tideland and/or wetland soils in estuarine area at Saemankum, Kunsan in southwestern Korea during from months of February to June 2006. Hourly averaged GHG soil emissions were measured two to three times a day during the ebb tide hours only. Site soils were analyzed for soil parameters (temperature, pH, total organic contents, N and C contents in soil) in the laboratory. Soil GHG fluxes were calculated based on the GHG concentration rate of change measured inside a closed chamber The analysis of GHG was conducted by using a Gas Chromatography (equipped with ECD/FID) at laboratory. Changes of daily, monthly GHGs' fluxes were examined. The relationships between the GHG emissions and soil chemical contents were also scrutinized with respect to gas production and consumption mechanism in the soil. Soil pH was pH $7.47{\pm}0.49$ in average over the experimental period. Organic matter contents in sample soil was $6.64{\pm}4.98\;g/kg$, and it shows relatively lower contents than those in agricultural soils in Kunsan area. Resulting from the soil chemistry data, soil nitrogen contents seem to affect GHG emission from the tidal land surface. The tidal soil was found to be either source or sink for the major GHG during the experimental periods. The annual average of $CH_{4}\;and\;CO_{2}$ fluxes were $0.13{\pm}0.86\;mg\;m^{-2}h^{-1}\;and\;5.83{\pm}138.73\;mg\;m^{-2}h^{-1}$, respectively, which will be as a source of these gases. However, $N_{2}O$ emission showed in negative flux, and the value was $-0.02{\pm}0.66\;mg\;m^{-2}h^{-1}$, and it implies tidal land surface act as a sink of $N_{2}O$. Over the experimental period, the absolute values of gas fluxes increased with soil temperature in general. Averages of the ambient gas concentration were $86.8{\pm}6.\;ppm$ in $CO_{2},\;1.63{\pm}0.34\;ppm\;in\;CH_{4},\;and\;0.59{\pm}0.15\;ppm\;in\;N_{2}O$, respectively. Generally, under the presence of gas emission from agricultural soils, decrease of gas emission will be observed as increase in ambient gas concentration. We, however, could not found significant correlation between the ambient concentrations and their emissions over the experimental period. There was no GHG compensation points existed in tide flat soil.

• 신재생에너지
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• 제16권3호
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• pp.27-34
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• 2020

This study involved a total budget analysis on the greenhouse gas (GHGs) emissions of landfills, focusing on surface emissions and the effect on emissions reductions of generating landfill gas (LFG) electricity from March 7, 2007 to December 31, 2018. The GHGs reduction effect from the electricity generation using 536.6 × 10³ tCO₂ of CH₄ was only 5.8% of the GHGs from surface emissions of 9,191 × 10³ tCO₂. In the total budget, the collection ratio should be over 95% if the reduction effect is greater than the surface emissions. The correlation coefficient for the relationship between the LFG collection ratio and GHGs reduction was -0.89. An additional effect of lowering CH₄ content may occur if the surface emitting flux of LFG decreased with an increase in the collection ratio. The unit reduction effect of GHGs by suppressing surface emissions was 4174 tCO₂/TJ. This was far greater than that of LFG power generated (54.3 tCO₂/TJ), demonstrating that surface emission control is the most important measure by which to mitigate GHGs emission.

• 한국토양비료학회지
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• 제49권1호
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• pp.30-35
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• 2016

Rice cultivation in paddy field affects the global balance of methane ($CH_4$) as a key greenhouse gas. To evaluate a potential use of by-product gypsum fertilizer (BGF) in reducing $CH_4$ emission from paddy soil, $CH_4$ fluxes from a paddy soil applied with BGF different levels (0, 2, 4 and $8Mg\;ha^{-1}$) were investigated by closed-chamber method during rice cultivation period. $CH_4$ flux significantly decreased (p<0.05) with increasing level of BGF application. $8Mg\;ha^{-1}$ of BGF addition in soil reduced $CH_4$ flux by 60.6% compared to control. Decreased soil redox potential (Eh) resulted in increasing $CH_4$ emission through a $CO_2$ reduction reaction. The concentrations of dissolved calcium (Ca) and sulfate ion (${SO_4}^{2-}$) in soil pore water were significantly increased as the application rate of BGF increased and showed negatively correlations with $CH_4$ flux. Decreased $CH_4$ flux with BGF application implied that ${SO_4}^{2-}$ ion led to decreases in electron availability for methanogen and precipitation reaction of Ca ion with inorganic carbon including carbonate and bicarbonate as a source of $CH_4$ formation under anoxic condition. BGF application also increased rice grain yield by 16% at $8Mg\;ha^{-1}$ of BGF addition. Therefore, our results suggest that BGF application can be a good soil management practice to reduce $CH_4$ emission from paddy soil and to increase rice yield.

• 한국지구과학회지
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• 제34권3호
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• pp.209-223
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• 2013

이 연구의 목적은 한반도에서 $CH_4$ 농도의 수치모의 검증을 통하여 $CH_4$ 배출원의 기여 농도를 추정하는 것이고, 이 수치모의에 사용된 $CH_4$ 배출량을 상자모델로부터 추정된 $CH_4$ 배출량과 비교하는 것이다. 한반도에서 2010년 4월 1일부터 8월 22일까지 $CH_4$의 평균 농도를 추정하기 위해 WRF-CMAQ 모델이 사용되었다. 모델에서 $CH_4$ 배출량은 전지구 배출량인 EDGAR와 한국에서의 온실기체 배출량인 GHG-CAPSS로부터 인위적 배출 인벤토리와 전지구 자연적 인벤토리인 MEGAN이 적용되었다. 이들 $CH_4$ 배출량은 안면도 및 울릉도에서 측정된 $CH_4$ 농도와 모델링 농도 자료를 비교함으로써 검증되었다. 울릉도에서 국내 배출원으로부터 추정된 $CH_4$의 기여 농도는 약 20%로 나타났고, 이것은 한반도 내 농장(8%), 에너지 기여 및 산업공정(6%), 일반폐기물(5%), 생체 및 토지이용(1%) 등 $CH_4$ 배출원으로부터 기원하였다. 그리고 중국으로부터 수송된 $CH_4$의 기여 농도는 약 9%였고, 나머지 배경농도는 약 70%로 나타났다. 박스모델로 추정된 $CH_4$ 배출량은 WRF-CMAQ 모델에서 사용한 $CH_4$ 배출량과 유의미한 결과를 얻었다.