• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.2
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• pp.49-54
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• 2011

This study was conducted to evaluate the performance of methane fermentation from effluent of hydrogen fermentation reactor in anaerobic baffled reactor (ABR) and anaerobic sequencing batch reactor (ASBR). Two reactors were operated at organic loading rate of $1.0kg\;COD/m^3{\cdot}d$ and hydraulic retention time (HRT) of 20 day. Methane production rates of ABR and ASBR for start-up periods were 0.04 L/L/d and 0.19 L/L/d, respectively, whereas maximum methane production rates of ABR and ASBR were 0.25 L/L/d and 0.31 L/L/d, respectively. Removal rates of chemical oxygen demand (COD) in ABR and ASBR for start-up periods were 89% and 92%, respectively. After startup periods, removal rates of COD and volatile solids (VS) in ABR and ASBR were maintained over 90%. The specific methanogenic activity (SMA) increased as microorganism acclimated to the substrate.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.3
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• pp.5-13
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• 2019

This study is conducted to investigate the effects of anaerobic treatments of swine manure slurry alone and combination of livestock manure slurry and fruit pomace on biogas production. Anaerobic co-digestion was evaluated in mesophilic tank reactors for 96 day-incubation period. The organic matter loading of anaerobic digestion was 1 kg of volatile solids(VS) per $1m^3{\cdot}day$. The highest methane production was achieved from the combination of swine manure slury and mandarin pomace(70:30) treatment, whereas the lowest daily and cumulative methane yields was observed in swine manure slurry alone treatment. More than two-fold increase in bio-gas and methane production was obtained by combination of livestock manure slurry and mandarin pomace treatment, compared to the swine manure slurry alone treatment. The co-digestion of livestock manure and fruits pomace has advantages to enhance the production of methane gas, compared to digestion of swine manure slurry alone.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.4
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• pp.5-10
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• 2018

In this study, the effect of physico-chemical factors (e.g., pressure, electrolyte, and organic matter) in the gas hydrate deposit on CH4-CO2 replacement process was investigated experimentally. The higher initial pressure during gas injection led the higher reaction rate at the first time, but finally it did not. Electrolytes and organic matter have some effects on reforming process after dissociation of gas hydrate. It is expected that further research using real marine sediments with actual gas hydrate will enable the development of technologies applicable to the characteristics of domestic seabed geology. Ultimately, it is expected that it will be possible to recover and utilize methane as an organic resource through application of domestic gas hydrate deposit in the Ulleung Basin, East Sea.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.331-339
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• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a pilot scale two-phase anaerobic system operated up to a volumetric rate of $10m^3/day$. The pilot scale two-phase anaerobic process is consisted of a continuous-flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. The acidogenic CFSTR was operated at organic loading rates (OLR) between 1.8 and $14.4kgCOD/m^3{\cdot}day$, and the UASB reactor was operated between 0.5 and $5.6kgCOD/m^3{\cdot}day$. A stable maximum biogas production rate was $81m^3/day$ and the methane conversion rate of the organic matter varied from 0.30 to $0.42L\;CH_4/g\;COD_{removed}$(0.40) at hydraulic retention time (HRT) above 3.5days. The methane contents ranged from 73 to 82% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• Journal of Korean Society on Water Environment
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• v.35 no.4
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• pp.362-369
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• 2019

In this study, biodegradation efficiency improvement of mixed sludge for the anaerobic digestion process in wastewater treatment plant was investigated. In order to release the organic material contained in the sludge cell and promote the hydrolysis step, mixed sludge of 7% TS (Total Solids) was physically shear-treated at a shear strength of 1,000 ~ 4,000 rpm and a maximum of 120 mins. As a result of the comparison between mixed sludge before and after the treatment, the concentration of $SCOD_{Cr}$(Soluble Chemical Oxygen Demand-chromium method) was increased through the conversion of granular organic matter into dissolved organic matter as shear strength and treatment time increases. The solubilization efficiency increased rapidly after 30 min of solubilization application time, and they were 11.23 %, 20.10 %, 22.52 % and 25.43% at 120 min for each shear strength conditions, respectively. Additionally, the BMP(Biochemical Methane Potential) test was conducted with the optimized samples to determine the increase of methane production by the shear pre-treatment. Consequently, methane production of each samples were 0.275, 0.310, 0.323 and $0.335m^3/kg\;VS_{add}$, which indicates that methane production was increased to a maximum of 21.28% compared to the control without the solubilization process ($0.262m^3/kg\;VS_{add}$). As a result, the physical shear-treatment is a promising process for sewage sludge pre-treatment to reduce the organic waste and increase the energy production.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.306-313
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• 2014

BACKGROUND: Forest soils contain microbes capable of consuming atmospheric methane ($CH_4$), an amount matching the annual increase in $CH_4$ concentration in the atmosphere. However, the effect of plant residue production by different forest structure on $CH_4$ oxidation is not studied in Korea. The objective of this study was to evaluate the effect of Korean alpine soils having different forestation structure on $CH_4$ uptake rates. METHODS AND RESULTS: the $CH_4$ flux was measured at three sites dominated with pine, chestnut and oak trees in southern Korea. The $CH_4$ uptake potentials were evaluated by a closed chamber method for a year. The $CH_4$ uptake rate was the highest in the pine tree soil ($1.05mg/m^2/day$) and then followed by oak ($0.930mg/m^2/day$) and chestnut trees ($0.497mg/m^2/day$). The $CH_4$ uptake rates were highly correlated to soil organic matter and moisture contents, and total microbial and methanotrophs activities. Different with the general concent, there was no any correlation between $CH_4$ oxidation rates, and soil temperature and labile carbon concentrations, irrespective with tree species. CONCLUSION: Conclusively, the methane oxidation rate was correlated in positive manner with organic matter, abundance of methanotrophs. Methane oxidation was different among tree species. This results could be used to estimate methane oxidation rate in forest of Korea after complementing information about statistical data and methane oxidation of other site.

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.3
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• pp.113-120
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• 2007

Anaerobic batch tests were performed to evaluate the characteristics of methane production from piggery manure such as the ultimate methane yield (UMY), the kinetic constant and the maximum methane production rate. The kinetic behavior of anaerobic degradation of piggery manure was assumed as a first order reaction. The UMY, the first order kinetic constant and the maximum methane production rate were 0.27~0.44L $CH_4/gVS$, $0.161{\sim}0.280d^{-1}$ and 0.043~0.120L $CH_4/d$, respectively. Reactor of piggery manure as the self-seed source of anaerobic digestion resulted in longer acclimation time than reactors seeded with anaerobic digested sludge (ADS). But there was no little difference in the UMY between the two seed materials. The anaerobic digestion can be effective for the treatment of piggery manure containing high concentration of solids, the two-stage anaerobic digestion is, however, thought to be more effective than the traditional single one.

• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.266-269
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• 1995

Methane emission was measured every two hours for a whole day at heading stage of rice plantsby using a closed static chamber installed in NPK(11-70-80 kg/ha) plot and NPK+rice straw(5 ton/ha) plots. The effect of air and soil temperature on methane emission was studied. In NPK plot the diel change of methane emission was synchronized better with soil temperature than air temperature because of abrupt rise of air temperature from 11 : 00 to 17 : 00 hours. In NPK+rice straw plot diel methane emission showed proportionally increased with increase of soil temperature except for times from 11 : 00~17 : 00 hours when air temperature was very high, but showed a closer relation with change of air temperature. It was suggested that the diel change of methane emission was closely related to that of air temperature where organic matter was abundant, while to that of soil temperature where organic matter was limited.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.4
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• pp.271-277
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• 2015

Anaerobic decomposition of organic material in flooded rice fields produces methane, which escapes to the atmosphere primarily by transport through the rice plants. The annual amount of $CH_4$ emitted from a given area of rice is a function of the number and duration of crops grown, water regimes before and during cultivation period, and organic and inorganic soil amendments. Soil type, temperature, and rice cultivar also affect $CH_4$ emissions. The field experiment was conducted for three years to develop methane emission factor for water regime before the cultivation period from the rice fields. It was treated with three different water regimes prior to rice cultivation, namely: non-flooded pre-season < 180 days, non-flooded pre-season > 180 days, flooded per-season in which the minimum flooding interval is set to 30 days. Methane emission increased with days after transplanting and soil redox potential (Eh) decreased rapidly after flooding during the rice cultivation. The average methane emission fluxes were $5.47kg\;CH_4\;ha^{-1}day^{-1}$in flooded pre-season > 30 days, 5.04 in non-flooded pre-season < 180 days and 4.62 in non-flooded pre-season > 180. Methane emission flux was highly correlated with soil temperature and soil Eh. Rice yields showed no difference among treatments with water regime before the cultivation period.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.427-434
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• 2023

Large amounts of organic wastes generated in agricultural environments such as crop residues and livestock manure adversely affect the environment. Anaerobic digestion can reduce the amount of organic wastes and convert them into energy at the same time. Efforts are being made to further increase the energy conversion efficiency by using co-anaerobic digestion using two or more substrates. Tomatoes, rice straw, cattle manure, and cattle feces (CF) were used as substrates for anaerobic digestion. Each substrate was subjected to anaerobic digestion and the cumulative biochemical methane production potential was measured, and the biodegradability was calculated. Based on the methane production, CF and tomato were further used for co-anaerobic digestion at different mixing ratios. Among the CF:tomato ratios of 1:1, 1:2, and 2:1, 1:2 produced the most methane and the synergy index was greater 1 indicating that the co-digestion of CF and tomato improved the methane production. Overall, the results showed that the methane production from cattle manure can be improved using tomato residues.