• Asian-Australasian Journal of Animal Sciences
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• 제24권2호
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• pp.295-302
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• 2011

Almost half of New Zealand's greenhouse gas emissions arise from agriculture and enteric methane ($CH_4 $) emissions arising from ruminant animals constitute 30% of total $CO_2$-e emissions. Enteric $CH_4$ emissions have increased by 9% since 1990. Extensive research has been undertaken to develop reliable methods for measuring enteric $CH_4$ emissions. New Zealand studies using the SF6 tracer technique suggest that on average this technique yields similar values to the 'gold' standard of calorimetry, but with a larger variance. National inventory estimates based on results obtained using the $SF_6$ technique will therefore overestimate the uncertainty. Mitigating emissions can be achieved by changing feed type but there are practical and cost barriers to the use of alternative feeds. Forages containing condensed tannins do reduce emissions but are agronomically inferior to the forages currently used. Rumen additives have shown some success in-vitro but results from in-vivo trials with both monensin and fumaric acid have been disappointing. The development of methods for directly manipulating rumen microorganisms are at an early stage and work to develop vaccines that can inhibit methanogenesis has yielded mixed results. The successful identification of sheep with contrasting $CH_4$ yields raises the possibility that, in the long term, a breeding approach to $CH_4$ mitigation is feasible.

• 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.

• 한국방재안전학회논문집
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• 제16권4호
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• pp.45-59
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• 2023

세계적으로 온실가스 감축을 위해 주로 이산화탄소 발생에 초점을 맞춰왔지만, 최근에는 메탄 발생에 대한 관심이 커지고 있다. 습지, 저수지, 호소 등 수중 환경을 포함한 자연은 온실 가스 중요한 발원지이다. 호수와 저수지 바닥에 쌓인 퇴적된 유기 오염물질은 산소가 부족한 상태에서 미생물 분해를 통해 메탄과 같은 온실 가스를 생성할 수 있다. 메탄 배출은 비점오염원의 증가와 하천에 설치되는 횡단 구조물에 의한 흐름변화에 의해 증가하고 있는 실정이다. 또한, 기후 변화로 인한 수온의 상승 등은 메탄 배출을 가속화하는 원인이다. 메탄은 다양한 경로를 통해 대기로 배출될 수 있다. 따라서, 본 연구에서는 메탄발생의 주요인자가 미치는 영향을 정량화하기 위하여 BMP test을 수행하였다. 실험조건에 따라 메탄발생량을 직접 계측하였으며, 실험조건은 온도, 기질의 종류, 전단응력 및 퇴적물 특성으로 구분하였다. 또한, 바닥의 전단 응력은 실험적으로 측정하기가 어려워 수치모의를 수행하였다. 실험결과, 생화학적 요소는 메탄 생성에 영향을 미치지만, 전단 속도는 메탄 분리에 영향을 미치는 것으로 나타났으며, 퇴적물 특성은 메탄 생성 및 분리에 영향을 미칠 수 있다. 메탄 생성과 주요인자들 간의 관계를 경험식으로 제시하였으며, 향후 전단응력 및 유기물에 대한 실험조건을 구체화하고 실험규모를 확대한다면 메탄발생과 생지화학 및 수환경인자간의 관계를 도출할 수 있을 것으로 기대된다.

• 한국환경보건학회지
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• 제34권6호
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• pp.414-422
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• 2008

Methane is a potent greenhouse gas and methane emissions from landfill sites have been linked to global warming. In this study, LandGEM (Landfill Gas Emission Model) was applied to predict landfill gas quantity over time, and then this result was compared with the data surveyed on the site, Cheongju Megalo Landfill. LandGEM allows the input of site-specific values for methane generation rate (k) and potential methane generation capacity $L_o$, but in this study, k value of 0.04/yr and $L_o$ value of $100\;m^3$/ton were considered to be most appropriate for reflecting non-arid temperate region conventional landfilling like Cheongju Megalo Landfill. Relatively high discrepancies between the surveyed data and the predicted data about landfill gas seems to be derived from insufficient compaction of daily soil-cover, inefficient recovery of landfill gas and banning of direct landfilling of food waste in 2005. This study can be used for dissemination of information and increasing awareness about the benefits of recovering and utilizing LFG (landfill gas) and mitigating greenhouse gas emissions.

• 한국대기환경학회지
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• 제23권3호
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• pp.344-352
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• 2007

Quantifying the methane emission from landfills is important to evaluate measures for reduction of greenhouse gas emissions. To estimate methane emission for the entire landfills from 1990 through 2004 in Korea, Tier 1 and 2 methodologies were used. In addition, five different scenarios were adopted to identify the effect of important variables on methane emission. The trends of methane emission using Tier 1 were similar to the disposed waste amount. Methane emission using Tier 2 increased as the degradation of waste was gradually proceeded. This result indicates that disposed waste amount and methane generation rate are the important variables for the estimation of methane emission by Tier 1 and 2, respectively. As for the different scenarios, methane emission was highest with scenario I that the entire landfills in Korea were regarded as one landfill. Methane emissions by scenario III and IV considering different $DOC_F$ values with the waste type and different MCF values with the height of waste layer, respectively, were underestimated compared to scenario II. This result indicates that the method of scenario I employed to most previous studies may lead to the overestimation of methane emission. Therefore, more careful consideration of the variables should be needed to develop the methodologies of greenhouse gas emission in landfills along with the characteristics of disposed waste in Korea.

• Animal Bioscience
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• 제37권2호
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• pp.173-183
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• 2024

Objective: This study aimed to evaluate whether the methane (CH₄) to carbon dioxide (CO₂) ratio (CH₄/CO₂) and methane-related traits obtained by the sniffer method can be used as indicators for genetic selection of Holstein cows with lower CH₄ emissions. Methods: The sniffer method was used to simultaneously measure the concentrations of CH₄ and CO₂ during milking in each milking box of the automatic milking system to obtain CH₄/CO₂. Methane-related traits, which included CH₄ emissions, CH₄ per energy-corrected milk, methane conversion factor (MCF), and residual CH₄, were calculated. First, we investigated the impact of the model with and without body weight (BW) on the lactation stage and parity for predicting methane-related traits using a first on-farm dataset (Farm 1; 400 records for 74 Holstein cows). Second, we estimated the genetic parameters for CH₄/CO₂ and methane-related traits using a second on-farm dataset (Farm 2; 520 records for 182 Holstein cows). Third, we compared the repeatability and environmental effects on these traits in both farm datasets. Results: The data from Farm 1 revealed that MCF can be reliably evaluated during the lactation stage and parity, even when BW is excluded from the model. Farm 2 data revealed low heritability and moderate repeatability for CH₄/CO₂ (0.12 and 0.46, respectively) and MCF (0.13 and 0.38, respectively). In addition, the estimated genetic correlation of milk yield with CH₄/CO₂ was low (0.07) and that with MCF was moderate (-0.53). The on-farm data indicated that CH₄/CO₂ and MCF could be evaluated consistently during the lactation stage and parity with moderate repeatability on both farms. Conclusion: This study demonstrated the on-farm applicability of the sniffer method for selecting cows with low CH₄ emissions.

• 한국미생물·생명공학회지
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• 제37권4호
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• pp.293-305
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• 2009

메탄은 온실효과가 이산화탄소 보다 20배 이상인 대표적인 non-$CO_2$ 온실가스이다. 매립지는 주요 인위적 메탄 발생원으로, 매립지의 메탄 발생량은 연간 35~73 Tg(tera gram)으로 추정된다. 바이오커버(개방형 시스템)과 바이오필터(폐쇄형 시스템)을 이용하는 생물학적 방법은 메탄을 회수하여 자원화하기에는 메탄 농도가 너무 낮거나 가스 포집정이 설치되어 있지 않는 노후화된 매립지나 소규모 매립지로부터 메탄 배출을 저감할 수 있는 유용한 방법이다. 메탄을 유일탄소원과 에너지원으로 활용하는 메탄산화세균은 이러한 생물학적 방법에 있어 메탄을 산화시켜 제거하는데 매우 중요한 역할을 담당한다. 토양, compost, 지렁이 분변토 등과 같은 다양한 충전재를 이용하여 실험실 규모의 바이오커버/바이오필터의 메탄산화효율에 관한 많은 연구가 진행되었다. 이 중에서 compost는 가장 많이 이용되고 있는 충전재이고, compost를 이용한 바이오커버/바이오필터의 메탄산화속도는 50에서 $700\;g-CH_4\;m^{-2}\;d^{-1}$로 보고되고 있다. 또한, 실제 매립지에 파일럿 규모의 바이오커버/바이오필터를 설치하여 메탄 배출 저감 효과에 관한 연구도 진행되고 있다. 매립지의 메탄 배출 저감은 탄소배출권 거래와 연관될 수 있으므로, 바이오커버/바이오필터에 의한 메탄 저감량을 정확하게 평가하는 것이 매우 중요하다. 그러므로, 매립지 현장에 설치된 바이오커버/바이오필터의 성능을 평가하는 방법은 표준화되어야 하며, 메탄 저감량을 정확하게 정량화할 수 있는 방법 개발이 필요하다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1426-1435
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• 2014

Saponins have been considered as promising natural substances for mitigating methane emissions from ruminants. However, studies reported that addition of saponin-rich sources often arrived at contrasting results, i.e. either it decreased methane or it did not. The aim of the present study was to assess ruminal methane emissions through a meta-analytical approach of integrating related studies from published papers which described various levels of different saponin-rich sources being added to ruminant feed. A database was constructed from published literature reporting the addition of saponin-rich sources at various levels and then monitoring ruminal methane emissions in vitro. Accordingly, levels of saponin-rich source additions as well as different saponin sources were specified in the database. Apart from methane, other related rumen fermentation parameters were also included in the database, i.e. organic matter digestibility, gas production, pH, ammonia concentration, short-chain fatty acid profiles and protozoal count. A total of 23 studies comprised of 89 data points met the inclusion criteria. The data obtained were subsequently subjected to a statistical meta-analysis based on mixed model methodology. Accordingly, different studies were treated as random effects whereas levels of saponin-rich source additions or different saponin sources were considered as fixed effects. Model statistics used were p-value and root mean square error. Results showed that an addition of increasing levels of a saponin-rich source decreased methane emission per unit of substrate incubated as well as per unit of total gas produced (p<0.05). There was a decrease in acetate proportion (linear pattern; p<0.001) and an increase in propionate proportion (linear pattern; p<0.001) with increasing levels of saponin. Log protozoal count decreased (p<0.05) at higher saponin levels. Comparing between different saponin-rich sources, all saponin sources, i.e. quillaja, tea and yucca saponins produced less methane per unit of total gas than that of control (p<0.05). Although numerically the order of effectiveness of saponin-rich sources in mitigating methane was yucca>tea>quillaja, statistically they did not differ each other. It can be concluded that methane mitigating properties of saponins in the rumen are level- and source-dependent.

• 한국환경보건학회지
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• 제46권2호
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• pp.159-169
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• 2020

Objectives: The purpose of this study was to investigate changes among the nine kinds of reduction chemical substances in Korea over the period of 2008-2017. We will define basic data for improving the management methods for reducing chemical substances. Methods: A survey of hazardous pollutant emissions for 2008-2017 was conducted through the pollutant Release and Transfer Register homepage. Nine kinds of designated reduction chemical substances (Benzene, Vinyl chloride, Trichloro ethylene, 1,3-butadiene, Dichloro methane, Tetrachloro ethylene, N,N-dimethylformamide, Acrylo nitrile, and Chloroform) provided the study subjects. The emission of hazardous chemicals and health effects used the National Health Statistics and Integrated Chemicals Information System (ICIS) as a reference. Results: Hazardous pollutant emissions increased by 1.2 times over the past decade, and nine types of reduction chemical substances increased by 1.6 times. By region, the emissions of reduction chemical substances over the last 10 years were in the order of Chungbuk, Gyeonggi, and Gyeongbuk. Emissions of Dichloro methane was the highest in Chungbuk and Gyeongbuk. N,N-dimethylformamide was the highest in Gyeonggi. Carcinogen pollutant emissions showed a tendency to increase continuously. In addition, group 1 carcinogen emissions showed a tendency to decrease. Conclusion: In the last decade, the amount of hazardous chemical emissions has been continuously increasing. Hazardous chemical emissions require facility improvement for continuous emissions reduction. More research on reduction of emissions is needed.

• Asian-Australasian Journal of Animal Sciences
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• 제25권12호
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• pp.1768-1774
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• 2012

This study was conducted to evaluate methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from livestock agriculture in 16 local administrative districts of Korea from 1990 to 2030. National Inventory Report used 3 yr averaged livestock population but this study used 1 yr livestock population to find yearly emission fluctuations. Extrapolation of the livestock population from 1990 to 2009 was used to forecast future livestock population from 2010 to 2030. Past (yr 1990 to 2009) and forecasted (yr 2010 to 2030) averaged enteric $CH_4$ emissions and $CH_4$ and $N_2O$ emissions from manure treatment were estimated. In the section of enteric fermentation, forecasted average $CH_4$ emissions from 16 local administrative districts were estimated to increase by 4%-114% compared to that of the past except for Daejeon (-63%), Seoul (-36%) and Gyeonggi (-7%). As for manure treatment, forecasted average $CH_4$ emissions from the 16 local administrative districts were estimated to increase by 3%-124% compared to past average except for Daejeon (-77%), Busan (-60%), Gwangju (-48%) and Seoul (-8%). For manure treatment, forecasted average $N_2O$ emissions from the 16 local administrative districts were estimated to increase by 10%-153% compared to past average $CH_4$ emissions except for Daejeon (-60%), Seoul (-4.0%), and Gwangju (-0.2%). With the carbon dioxide equivalent emissions ($CO_2$-Eq), forecasted average $CO_2$-Eq from the 16 local administrative districts were estimated to increase by 31%-120% compared to past average $CH_4$ emissions except Daejeon (-65%), Seoul (-24%), Busan (-18%), Gwangju (-8%) and Gyeonggi (-1%). The decreased $CO_2$-Eq from 5 local administrative districts was only 34 kt, which was insignificantly small compared to increase of 2,809 kt from other 11 local administrative districts. Annual growth rates of enteric $CH_4$ emissions, $CH_4$ and $N_2O$ emissions from manure management in Korea from 1990 to 2009 were 1.7%, 2.6%, and 3.2%, respectively. The annual growth rate of total $CO_2$-Eq was 2.2%. Efforts by the local administrative offices to improve the accuracy of activity data are essential to improve GHG inventories. Direct measurements of GHG emissions from enteric fermentation and manure treatment systems will further enhance the accuracy of the GHG data.