• 유기물자원화
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• 제19권3호
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• pp.29-34
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• 2011

본 연구에서는 맥주 생산 공정에서 발생되는 고농도 유기성 폐수를 처리하는데 혐기성 필터를 사용하였다. 전체 운전 기간 동안, 메탄 생산과 맥주 폐액 처리가 효과적으로 이루어졌다. BOD, CODcr, SS, TN, TP의 평균 처리효율은 각각 61.4 %, 60.9 %, 31.4 % 70.7 %, 70.0 %를 나타내었다. 그리고, 전체가스 중 메탄 함량과 메탄 생산량은 각각 68. 8 %와 $0.08{\sim}0.77m^3CH_4/kgCOD$가 됨을 알 수 있었다. 이번 연구를 통하여 개발된 기술은 맥주 폐액 처리와 메탄 생산성 향상에 효과적인 방법으로서 실질적인 혐기 소화 처리로 사용될 수 있을 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제29권1호
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• pp.73-79
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• 2016

The objective was to evaluate the effect of fodder tree species (FTS) with condensed tannin contents: Cordia elaeagnoides, Platymiscium lasiocarpum, Vitex mollis, and Haematoxylon brasiletto, on in vitro methane ($CH_4$) production at 24 h post incubation. The analysis was performed using the in vitro gas production technique, with three levels of inclusion/species: 600, 800, and 1,000 mg and with 4 replicates/species/level of inclusion. The substrate was incubated at $39^{\circ}C$, and the gas and $CH_4$ production were recorded at 4, 8, 12, and 24 h post incubation. The data collected was analyzed through Pearson correlation, polinomial regression and fixed effects models. There were negative correlations between FTS-total gas volume (r = -0.40; p<0.001); FTS-volume of $CH_4$ produced (r = -0.40; p<0.001) and between the inclusion level-volume of $CH_4$ produced (r = -0.20; p<0.001). As well as a positive correlation between hours post incubation-total gas volume (r = 0.42; p<0.001) and between hours post incubation-volume of $CH_4$ produced (r = 0.48; p<0.001). The FTS: C. elaeagnoides, V. mollis, and H. brasiletto have potential, in the three inclusion levels analyzed, to reduce $CH_4$ emission on in vitro trials (>32.7%), taking into account the total $CH_4$ production at 24 h of the forage used as reference (Avena sativa). It's suggested that C. elaeagnoides-according to its crude protein, neutral detergent fiber, and condensed tannins content- is the best alternative within the FTS analyzed, for feeding ruminants and for the control of $CH_4$ emissions during the dry season.

• Asian-Australasian Journal of Animal Sciences
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• 제23권5호
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• pp.563-566
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• 2010

Using an open-circuit system, we compared the methane ($CH_4$) emission from dry cows fed first-cut Timothy silage ($1^{st}$ TY), second-cut Timothy silage ($2^{nd}$ TY), second-cut Italian ryegrass silage ($2^{nd}$ IR), third-cut Italian ryegrass silage ($3^{rd}$ IR), or second-cut red clover silage ($2^{nd}$ RC) as the sole feed. The methane emission ranged from 258.2 L $day^{-1}$ to 396.5 L $day^{-1}$. The methane emission from dry cows fed red clover silage was relatively lower than that from dry cows fed grass silage. However, the methane emission per unit digestible neutral detergent fiber (NDF) intake (dNDFI) did not differ significantly between the experimental silages. The methane emission was significantly correlated with the NDF intake and digestibility. Methane emission had a significant correlation with the quadratic function of dNDFI. The differences in the daily volume of methane emission from cows fed different forages can be explained by dNDFI.

• 한국물환경학회지
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• 제32권3호
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• pp.297-302
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• 2016

Microbial electrochemical technology (MET) has recently been studied to improve the efficiency of a traditional anaerobic digestion (AD). The purpose of this study was to investigate the impact of MET in the system when MET was combined with traditional AD (i.e., AD-MET). Electrodes used in the MET were Cu coated graphite electrodes. They were supplied with a voltage of 0.3 V. AD started to generate methane in 80 days. But AD-MET started to generate methane from the initial operation after the system started. It was observed that AD-MET reached steady state faster and produced higher methane yield than AD. During the steady state, the average daily methane productions in AD and AD-MET were 2.3L/d and 4.9L/d, respectively. Methane yields were 0.07-CH₄/g‧CODre in AD and 0.25L-CH₄/g‧CODre in AD-MET. In AD-MET, the production rates of total volatile fatty acids (TVFAs) and soluble chemical oxygen demand (SCOD) were 0.12 mg TVFAs/mg VS‧d and 0.35 mg SCOD/mg VS‧d, respectively. They were significantly (p < 0.05) higher than those in AD. However, the concentrations of residual TVFAs in both systems were not significantly (p > 0.05) different from each other, confirming that methane conversion in AD-MET was greater than that in AD.

• 한국토양비료학회지
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• 제30권1호
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• pp.41-45
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• 1997

논 토양에서 메탄의 생성과 배출 토양깊이에 따른 토양용액내 메탄 확산 등을 구명코자 미사질 양토인 호남농업시험장 시험포장에서 수행한 결과는 다음과 같다. 1. 시기별 메탄 flux는 유수형성기 및 출수기에서 높았으며, 유기물을 시용한 구에서는 유기물 무시용구에 보다 배이상이 높았고, 일중 메탄 flux 변화는 야간에 비해 주간에 높았다. 2. 유기물 시용구에서 토양내 메탄 생성량은 생육초기부터 높았으며 분얼기에 감소하였다가 유수형성기 이후 증가하는 경향이었다. 3. 토양용액중 메탄 함량은 토심 5cm에서 가장 높았으며, 메탄의 확산은 매우 느린 경향이었다. 4. 토양 용액중 Eh는 -150~-160mV 범위였으며 메탄 생성과 밀접한 관련이 있었다.

• 공업화학
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• 제19권6호
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• pp.680-684
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• 2008

Silica sand 내에서의 메탄 하이드레이트($CH_4$ hydrate)의 형성과 분해는 $7.0^{\circ}C$의 온도에서 실험되었다. Silica sand 내에서 형성되는 메탄 하이드레이트의 형성 및 분해 특성을 연구하기 위해 새로운 반응기를 제작하였다. Silica sand bed 내에서 메탄하이드레이트의 형성과 분해되는 동안의 온도변화에 대한 연구를 위해 반응기 내의 주입한 silica sand 높이에 따라 열전대의 위치를 다르게 설치하여 실험하였다. 반응기 내에 가해지는 압력과 온도는 메탄 하이드레이트의 형성과 분해를 발생시키는 요인이다. 메탄 하이드레이트 형성을 위한 가스 흡착곡선과 분해실험을 위한 가스 발생곡선은 실험데이터로부터 결정되었다. 8 MPa의 압력에서 $7.0^{\circ}C$의 온도에서 메탄 하이드레이트 형성 실험을 수행한 결과 70%의 메탄이 하이드레이트로 전환됨을 알 수 있었다. 형성된 메탄 하이드레이트의 분해에 의한 메탄의 회수율은 82%였다.

• Animal Bioscience
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• 제37권3호
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• pp.481-491
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• 2024

Objective: This study determined fermentation characteristics of commonly used feedstuffs, especially tropical roughages, for dairy cattle in Southeast Asia. This information is considered relevant in the context of the observed low milk fat content and milk production in Southeast Asia countries. Methods: A total of 29 feedstuffs commonly used for dairy cattle in Vietnam and Thailand were chemically analysed and subjected to an in vitro gas production (GP) test. For 72 h, GP was continuously recorded with fully automated equipment and methane (CH₄) was measured at 0, 3, 6, 9, 12, 24, 30, 36, 48, 60, and 72 h of incubation. A triphasic, nonlinear, regression procedure was applied to analyse GP profiles while a monophasic model was used to obtain kinetics related to CH₄ production. Results: King grass and VA06 showed a high asymptotic GP related to the soluble- and non-soluble fractions (i.e. A1 and A2, respectively) and had the highest acetate to propionate ratio in the incubation fluid. The proportion of CH₄ produced (% of GP at 72 h) was found to be not different (p>0.05) between the various grasses. Among the selected preserved roughages (n = 6) and whole crops (n = 4), sorghum was found to produce the greatest amount of gas in combination with a relatively low CH₄ production. Conclusion: Grasses belonging to the genus Pennisetum, and whole crop sorghum can be considered as suitable ingredients to formulate dairy rations to enhance milk fat content in Vietnam/Thailand.

• 농촌계획
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• 제27권3호
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• pp.21-33
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• 2021

Rice straw management and winter crop cultivation are crucial components for the accurate estimation of paddy methane emissions. Field-based extensive investigation of paddy organic matter management requires enormous efforts however it becomes more feasible as drone technology advances. The objectives of this study were to identify paddy fields of straw application and winter crop cultivation using drone images and to apply for the estimation of yearly methane emission. Total 35 sites of over 150ha in area were selected nationwide as the study areas. Drone images of the study sites were taken twice during summer and winter in 2018 through 2019: Summer images were used to identify paddy cultivation areas, while winter images for straw and winter crop practices. Drone-image-based identification results were used to estimate paddy methane emission and compared with conventional method. As the result, mean areas for paddy, straw application and winter crop cultivation were 118.9ha, 12.0ha, and 11.3ha, respectively. Overall rice straw application rate were greater in Gyeonggi-do(20%) and Chungcheongnam-do(12%), while winter crop cultivation was greatest in Gyeongsangnam-do(30%) and Jeolla-do(27%). Yearly mean methane emission was estimated to be 226.2kg CH₄/ha/yr in this study and about 32% less when compared to 331.8kg CH₄/ha/yr estimated with the conventional method. This was primarily because of the lower rice straw application rate observed in this study, which was less than quarter the rate of 55.62% used for the conventional method. This indicates the necessity to use more accurate statistics of rice straw application as well as winter crop practices into paddy methane emission estimation. Thus it is recommended to further study to link drone technology with satellite image analysis in order to identify organic management practices at a paddy field level over extensive agricultural area.

• Animal Bioscience
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• 제34권4호
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• pp.584-593
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• 2021

Objective: The objective of this study was to compare fenugreek (FG) with alfalfa (Alf) in ruminal fermentation and methane (CH4) production in vitro. Methods: Whole-plant FG harvested at 11- and 15-wk and Alf harvested at early and mid-bloom maturities, alone or as 50:50 mixture of FG and Alf at the respective maturity, were assessed in a series of 48-h in vitro batch culture incubations. Total fermentation gas and methane gas production, dry matter (DM) disappearance, volatile fatty acids, microbial protein and 16S RNA gene copy numbers of total bacteria and methanogens were determined. Results: Compared to early bloom Alf, FG harvested at 11-wk exhibited higher (p<0.05) in vitro DM and neutral detergent fibre disappearance, but this difference was not observed between the mid-bloom Alf and 15-wk FG. Regardless plant maturity, in vitro ruminal fermentation of FG produced less (p<0.001) CH4 either on DM incubated or on DM disappeared basis than that of Alf during 48-h incubation. In vitro ruminal fermentation of FG yielded similar amount of total volatile fatty acids with higher (p<0.05) propionate percentage as compared to fermentation of Alf irrespective of plant maturity. Microbial protein synthesis was greater (p<0.001) with 11-wk FG than early bloom Alf as substrate and 16S RNA gene copies of total bacteria was higher (p<0.01) with 15-wk FG than mid-bloom Alf as substrate. Compared to mid-bloom Alf, 15-wk FG had lower (p<0.05 to 0.001) amount of 16S RNA methanogen gene copies in the whole culture during 48-h incubation. Conclusion: In comparison to Alf, FG emerges as a high quality forage that can not only improve rumen fermentation in vitro, but can also remarkably mitigate CH4 emissions likely due to being rich in saponins.

• Animal Bioscience
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• 제35권6호
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• pp.838-846
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• 2022

Objective: Native plants can be used as additives to replace antibiotics to improve ruminant feed utilization and animal health. An experiment was conducted to evaluate the effects of Gentiana straminea (GS) on nutrient digestibility, methane emissions, and energy metabolism of Simmental calves. Methods: Thirty-two (5-week-old) male Simmental clves, with initial body weight (BW) of 155±12 kg were fed the same basal diet of concentrates (26%), alfalfa hay (37%), and oat hay (37%) and were randomly separated into four treatment groups according to the amount of GS that was added to their basal diet. The four different groups received different amounts of GS as a supplement to their basal diet during whole experiment: (0 GS) 0 mg/kg BW, the control; (100 GS) 100 mg/kg BW; (200 GS) 200 mg/kg BW; and (300 GS) 300 mg/kg BW. Results: For calves in the 200 GS and 300 GS treatment groups, there was a significant increase in dry matter (DM) intake (p<0.01), average daily gain (ADG) (p<0.05), organic matter intake (p<0.05), DM digestibility (p<0.05), neutral detergent fibre (NDF) digestibility (p<0.05), and acid detergent fibre (ADF) digestibility (p<0.05). Dietary GS supplementation result in quadratic increases of DM intake (p<0.01), ADG (p<0.05), NDF intake (p<0.05), and ADF intake (p<0.05). Supplementing the basal diet with GS significantly increased nitrogen (N) retention (p<0.001) and the ratio of retention N to N intake (p<0.001). Supplementing the basal diet with GS significantly decreased methane (CH₄) emissions (p<0.01), CH₄/BW^0.75 (p<0.05) and CH₄ energy (CH₄-E) (p<0.05). Dietary GS supplementation result in quadratic increases of CH₄ (p<0.01) and CH₄/DM intake (p<0.01). Compared with 0 GS, GS-supplemented diets significantly improved their gross energy intake (p<0.05). The metabolizable energy and digestive energy intake were significantly greater for calves in the 100 GS and 200 GS calves than for 0 GS calves (p<0.05). Conclusion: From this study, we conclude that supplementing calf diets with GS could improve utilization of feed, energy, and N, and may reduce CH₄ emissions without having any negative effects on animal health.