• 신재생에너지
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• 제4권2호
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• pp.21-30
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• 2008

Anaerobic digestion (AD) is the most promising method of treating and recycling of different organic wastes, such as OFMSW, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. degradation in the absence of oxygen, organic material is decomposed by anaerobes forming degestates such as an excellent fertilizer and biogas, a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to producing renewable energy and to reducing $CO_2$ and other GHG emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. A classification of the basic AD technologies for the production of biogas can be made according to the dry matter of biowaste and digestion temperature, which divide the AD process in wet and dry, mesophilic and thermophilic. The biogas produced from AD plant can be utilized as an alternative energy source, for lighting and cooking in case of small-scale, for CHP and vehicle fuel or fuel in industrials in case of large-scale. This paper provides an overview of the status of biogas production and utilization technologies.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.202-205
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• 2008

Anaerobic digestion(AD) is the most promising method of treating and recycling of different organic wastes, such as OFMSW, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. degradation in the absence of oxygen, organic material is decomposed by anaerobes forming degestates such as an excellent fertilizer and biogas, a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to producing renewable energy and to reducing $CO_2$ and other GHG emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. A classification of the basic AD technologies for the production of biogas can be made according to the dry matter of biowaste and digestion temperature, which divide the AD process in wet and dry, mesophilic and thermophilic. The biogas produced from AD plant can be utilized as an alternative energy source, for lighting and cooking in case of small-scale, for CHP and vehicle fuel or fuel in industrials in case of large-scale. This paper provides an overview of the status of biogas production and utilization technologies.

• Asian-Australasian Journal of Animal Sciences
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• 제31권12호
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• pp.1913-1922
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• 2018

Objective: To find out ways of improving fermentation quality of silage, the comparative analysis of fermentation characteristics and in vitro digestibility of tropical grasses silage applied with cellulases produced from Acremonium or Tricoderma species were studied in Thailand. Methods: Fresh and wilted Guinea grass and Napier grass silages were prepared with cellulases from Acremonium (AC) or Trichoderma (TC) at 0.0025%, 0.005%, and 0.01% on a fresh matter (FM), and their fermentation quality, chemical composition and in vitro digestibility were analyzed. Results: All silages of fresh Napier grass were good quality with lower pH, butyric acid, and ammonia nitrogen, but higher lactic acid content than wilted Napier grass and Guinea grass silage. Silages treated with AC 0.01% had the best result in terms of fermentation quality. They also had higher in vitro dry matter digestibility and in vitro organic matter digestibility at 6 and 48 h after incubation than other silages. Silages treated with lower levels at 0.005% or 0.0025% of AC and all levels of TC did not improve silage fermentation. Conclusion: The AC could improve silage fermentation and in vitro degradation of Guinea grass and Napier grass silages, and the suitable addition ration is 0.01% (73.5 U) of FM for tropical silage preparation.

• Asian-Australasian Journal of Animal Sciences
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• 제18권9호
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• pp.1249-1254
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• 2005

The aim of this study was to determine the effect of maturity stage on the nutritive value of wild mustard straw in terms of chemical composition, in situ, in vitro dry matter degradability and calculated ME. The nutritive values of wild mustard, Sinapsis arvensis hays harvested at three stages were evaluated by chemical composition, in vitro gas production and in situ dry matter degradation methods. Gas production or dry matter (DM) degradation were determined at 0, 3, 6, 12, 24, 48, 72 and 96 h and their kinetics were described using the equation p = a+b(1-e$^{-ct}$). Maturity had a significant effect on both the chemical composition and degradability of wild mustard. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) (p<0.001) increased with increasing maturity whereas the crude protein (CP) (p<0.001) decreased. The gas produced after 96 h incubation ranged between 64.7 and 81.5 ml per 0.200 g of dry matter. The gas production (ml) at all incubation times and estimated parameters decreased with increasing maturity of wild mustard. The gas production at all incubation times and estimated parameters (a, b (a+b), metabolizable energy (ME) and organic matter digestibility (OMD)) were negatively correlated with NDF and ADF. The DM disappearance after 96 h incubation ranged between 50.8 and 76.1%. The in situ DM disappearance at all incubation times and estimated parameters decreased with increasing maturity of wild mustard. The in situ dry matter disappearance at all incubation times and some estimated parameters (c, a, b and effective dry matter degradability (EDMD)) were negatively correlated with NDF and ADF but positively correlated with CP. The nutritive value of wild mustard continually changed as it matured. Wild mustard, harvested at the proper stage of maturity offers considerable potential as a high quality forage for ruminants during the winter feeding period. The present study showed that if higher quality forage is an objective, wild mustard should be harvested at the early flowering stage.

• Environmental Engineering Research
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• 제20권2호
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• pp.149-154
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• 2015

In recent years, immobilization agents were introduced into organic contaminated soil remediation and more and more materials were screened and used as the immobilizing carrier. However, effect of the decomposition of the immobilizing carrier on the bioremediation was rarely concerned. Therefore, the decomposition experiment of immobilizing carrier -corncob was carried out in the lab with the efficient degradation fungi - Mucor mucedo (MU) existing, and polycyclic aromatic hydrocarbons (PAHs) residues E4/E6 of the dissolved organic matter and microbial diversity during the decomposition process were studied. The results showed that: a) during the decomposition, the degradation of pyrene (Pyr) was mainly in the first 28 d in which the content of extractable Pyr decreased rapidly and the highest decrease was in the treatment with only MU added. b) Anslysis of E4/E6 changes showed that rich microorganisms could promote aromatization and condensation of humus. c) From the diversity index analysis it can also be seen that there is no significant difference in effects of PAHs on the uniformity of microorganisms. These results will not only be useful to have a better understanding of the bioavailability of contaminants adsorbed to biodegradable carriers in PAHs contaminated soil remediation, but also be helpful to perfect the principle of immobilized microbial technique.

• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.335-340
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• 2018

Hemoglobin (Hb) is a member of heme-protein that can perform catalytic non-specific chain reaction in the presence of hydrogen peroxide ($H_2O_2$). Catalytic ability of Hb to degrade pyrene was demonstrated using soil contaminated with $^{14}C$ pyrene and 10 mg pyrene /kg soil. The composition of soil was similar to previously used soil except that it had lower organic carbon content. Bench scale laboratory tests were conducted in the presence of buffer only, $H_2O_2$ only, or Hb with $H_2O_2$ for 24 h. After 24 h reaction, 0.1 and 1.3% of $^{14}C$ pyrene in contaminated soil were mineralized with $H_2O_2$ only or Hb plus $H_2O_2$. No mineralization to $^{14}CO_2$ was detected with buffer only. Approximately 12.2% of pyrene was degraded in the presence of $H_2O_2$ only while 44.0% of pyrene was degraded in the presence of Hb plus $H_2O_2$ during 24 h of catalytic reaction. When degradation intermediate products were examined, two chemicals were observed in the presence of $H_2O_2$ only while 25 chemicals were found in the presence of Hb plus $H_2O_2$. While most degradation products were simple hydrocarbons, four of the 27 chemicals had aromatic rings. However, none of these four chemicals was structurally related to pyrene. These results suggest that Hb catalytic system could be used to treat pyrene-contaminated soil as an efficient and speedy remediation technology. In addition, intermediate products generated by this system are not greatly affected by composition change in soil organic matter content.

• 유기물자원화
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• 제8권4호
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• pp.160-167
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• 2000

음식물 퇴비화를 위한 토양미생물제재의 퇴비화 효율을 평가하며, 토양미생물제재의 미생물수와 퇴비화과정에서 식종의 효과를 조사하였다. 분석대상 음식물은 본 연구원 구내식당에서 수거한 후 물리화학적특성을 분석하였다. 대상시료는 Bulking Agent로서 톱밥을 사용하여 함수율을 65%로 조정 후 반응기 B에 10%의 토양미생물제를 식종하였다. 토양미생물제제의 미생물은 호기성세균수가 $2.98{\times}10^9/g$이상, 방선균이 $3.93{\times}10^7/g$이상, 효모가 $1.21{\times} 10^5/g$, 균류가 $5.79{\times}10^7/g$ 이상이었다. 퇴비화 기간동안 최고온도는 Reactor A가 반응 10일후에 개시후 바로 급격한 변화를 보였으며, 반응이 종료된 후 두 Reactor 공히 pH8.9를 나타내었다. Reactor B의 경우 최대온도인 4일후에 $CO_2$농도도 역시 최대인 10.8%를 나타냈으며, Reactor A는 최대온도인 10일후에 6.1%를 나타내었다. 한편 Reactor A는 $r_{d}$(유기물질의 분해율)치가 0.35에서 0.41로 17.1%상승하였으며, Reactor B의 경우 0.31에서 0.51로 64.5%상승하였다.

• 유기물자원화
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• 제16권3호
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• pp.46-51
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• 2008

리그닌이 분해되려면 분자형태의 산소를 요구하므로 혐기성 조건에서는 리그닌 분해가 어려운 것으로 알려져 왔다. 리그닌의 존재는 리그닌 분해에 영향을 준다. 리그닌 분해의 초기단계에서는 촉매역할을 하는 효소에 의해 리그닌이 중간산물로 분해되어 이 단계에서는 미생물에 의한 효소생성이 제한인자로 작용하게 된다. 폐수에 영양염을 첨가하고 미생물을 식종하여 폐수 내 유기물의 혐기성 분해정도를 평가할 수 있는 BMP(biochemical methane potential)법이 혐기성 조건하에서 리그닌 분해를 평가하기 위해 이용되고 있다. BMP법에 의해 리그닌을 초기 분해한 후 미생물 활동을 선택적으로 억제할 수 있도록 3% 톨루엔 용액으로 만든다. 이 용액의 리그닌 초기 분해율과 리그닌 분해산물의 축적률을 측정해 리그린의 혐기성 분해특성을 파악할 수 있다.

• Ocean and Polar Research
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• 제29권2호
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• pp.87-99
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• 2007

This study was conducted to understand the source and behavior of organic matter using the fluorescent technique (excitation-emission matrix) as a part of environmental monitoring program in the Korea manganese nodule mining site in the Northeastern Pacific Ocean. Water samples were collected at $0^{\circ},\;6^{\circ}N$, and $10.5^{\circ}N$ along $131.5^{\circ}W$ in August 2005. The concentration of total organic carbon (TOC) ranged from 58.01 to $171.93\;{\mu}M-C$. The vertical distribution of TOC was characterized as higher in the surface layer and decreased with depth. At $6^{\circ}N$, depth-integrated (from surface to 200 m depth) TOC was $337.1\;gC/m^2$, which was 1.4 times higher value than other stations. The exponential decay curve fit of vertical profile of TOC indicated that 59% of organic carbon produced by primary production in the surface layer could be decomposed by bacteria in the water column. Dissolved organic matter is generally classified into two distinctive groups based on their fluorescence characteristics using three-dimensional excitation/emission (Ex/Em) fluorescence mapping technique. One is known as biomacromolecule (BM; protein-like substance; showing max. at Ex 280/Em 330), mainly originated from biological metabolism. The other is geomacromolecule (GM; humic-like substance; showing max. at Ex 330/Em 430), mainly originated from microbial degradation processes. The concentration of BM and GM was from 0.42 to 7.29 TU (tryptophan unit) and from 0.06 to 1.81 QSU (quinine sulfate unit), respectively. The vertical distribution of BM was similar to that of TOC as high in the surface and decreased with depth. However, the vertical distribution of GM showed the reverse pattern of that of BM. From these results, it appeared that BM occupied a major part of TOC and was rapidly consumed by bacteria in the surface layer. GM was mainly transformed from BM by microbial processes and was a dominant component of TOC in the deep-sea layer.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.171-176
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• 2000

Bioremediation of hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), is a major environmental concern due to their toxic and carcinogenic properties. Due to their hydrophobicity, the hydrophobic organic compounds are mainly associated with the soil organic matter or nonaqueous-phase liquids. A major question concerns the relationships between biodegradation and sorption. This work develops and utilizes a non- steady state model for evaluating the interactions between sorption and biodegradation of phenanthrene, a 3-ring PAH compound, in soil-slurry systems. The model includes sorption/desorption of a target compound, its utilization by microorganisms as a primary substrate existing in the dissolved phase and/or the sorbed phase in biomass and soil, oxygen transfer, and oxygen utilization as an electron acceptor. Biodegradation tests with phenanthrene were conducted in liquid and soil-slurry systems. The soil-slurry tests were performed with very different mass transfer rate: fast mass transfer in a flask test at 150 rpm, and slow mass transfer in a roller-bottle test at 2 rpm. In the slurry tests, phenanthrene was degraded more rapidly than in liquid tests, but with a similar rate in both slurry systems. Modeling analyses with several hypotheses indicate that a model without biodegradation of compound sorbed to the soil was not able to account for the rapid degradation of phenanthrene, particularly in the roller bottle slurry test. Reduced mass-transfer resistance to bacteria attached to the soil is the most likely phenomenon accounting for rapid sorbed-phase biodegradation.