• Title, Summary, Keyword: Digestion

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A Study on the Treatment of Distillery Wastewater by Single-phase and Two-phase Anaerobic Digestion (단상(單相) 및 2상(相) 혐기성(嫌氣性) 소화(消化)에 의한 주정폐수(酒精廢水) 처리(處理)에 관한 연구(硏究))

  • Choung, Young Kyoo;Rah, Seung Woo;Park, Joon Hwan
    • Journal of Korean Society of Water and Wastewater
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    • v.7 no.1
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    • pp.5-12
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    • 1993
  • The objectives of this paper are to present data to illustrate how an advanced digestion process, two-phase digestion, can provide superior performance in terms of waste stabilization efficiency and net energy recovery. As the result, it is possible to separate enrichment cultures of acidogenic and methanogenic organisms in isolated environments by kinetic control involving manipulation of dilution rates. In single-phase digestion process, HRT and COD loading for effective operation were 14.29 days and 2.33kg $COD/m^3$ day, but two-phase digestion may be conducted efficiently at 7 days of HRT and 5.71kg $COD/m^3$ day of loading. Data from this studies showed that the two-phase process is better than single-phase digestion under all test conditions when compared on the bases of gas yield and production rate, reductions of COD and VS, buffer capacity, and unconverted volatile acids in the effluent.

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Determination of Heavy Metal in Polyurethane by New Digestion Method and ICP-AES (새로운 전처리 방법과 ICP-AES에 의한 폴리우레탄 중의 중금속 분석)

  • Lim, Heon-Sung;Lee, Sueg-Geun
    • Analytical Science and Technology
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    • v.17 no.4
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    • pp.363-367
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    • 2004
  • A simple and convenient digestion method was developed for the determination of heavy metal in polyurethane sample using only nitric acid in open system without heating. This digestion method had prevented loss of volatile elements of Hg and As and reduced the pretreatment time for the sample digestion. The detection limit is lowered over 10 times than that of microwave digestion method. Recoveries in polyurethane material were 108% for As, 96 ~ 99% for Hg, 102 ~ 103% for Cr, 98 ~ 102% for Pb, 86 ~ 90% for Cd, and 90 ~ 93% for Cu.

Rumen Microbes, Enzymes and Feed Digestion-A Review

  • Wang, Y.;McAllister, T.A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.11
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    • pp.1659-1676
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    • 2002
  • Ruminant animals develop a diverse and sophisticated microbial ecosystem for digesting fibrous feedstuffs. Plant cell walls are complex and their structures are not fully understood, but it is generally believed that the chemical properties of some plant cell wall compounds and the cross-linked three-dimensional matrix of polysaccharides, lignin and phenolic compounds limit digestion of cell wall polysaccharides by ruminal microbes. Three adaptive strategies have been identified in the ruminal ecosystem for degrading plant cell walls: production of the full slate of enzymes required to cleave the numerous bonds within cell walls; attachment and colonization of feed particles; and synergetic interactions among ruminal species. Nonetheless, digestion of fibrous feeds remains incomplete, and numerous research attempts have been made to increase this extent of digestion. Exogenous fibrolytic enzymes (EFE) have been used successfully in monogastric animal production for some time. The possibility of adapting EFE as feed additives for ruminants is under intensive study. To date, animal responses to EFE supplements have varied greatly due to differences in enzyme source, application method, and types of diets and livestock. Currently available information suggests delivery of EFE by applying them to feed offers the best chance to increase ruminal digestion. The general tendency of EFE to increase rate, but not extent, of fibre digestion indicates that the products currently on the market for ruminants may not be introducing novel enzyme activities into the rumen. Recent research suggests that cleavage of esterified linkages (e.g., acetylesterase, ferulic acid esterase) within the plant cell wall matrix may be the key to increasing the extent of cell wall digestion in the rumen. Thus, a crucial ingredient in an effective enzyme additive for ruminants may be an as yet undetermined esterase that may not be included, quantified or listed in the majority of available enzyme preparations. Identifying these pivotal enzyme(s) and using biotechnology to enhance their production is necessary for long term improvements in feed digestion using EFE. Pretreating fibrous feeds with alkali in addition to EFE also shows promise for improving the efficacy of enzyme supplements.

Kinetics of Anaerobic Digestion: A Comparative Study on Mesophilic and Thermophilic Anaerobic Digestion (혐기성소화(嫌氣性消化)의 동력학(動力學) : 중온(中溫) 및 고온혐기성소화(高溫嫌氣性消化)의 비교연구(比較研究))

  • Chang, Duk;Chung, Tai Hak
    • Journal of The Korean Society of Civil Engineers
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    • v.7 no.3
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    • pp.1-11
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    • 1987
  • Comprehensive laboratory experiments including digestion failures were conducted to identify differences between mesophilic and thermophilic digestion. Critical HRT was found to be near 10days for mesophilic and near 5days for thermophilic digestion. Inhibition occurred rapidly when operated below critical HRT. However, inhibition at mesophilic condition was much greater than that at thermophilic condition. Although digester performances were similar above critical HRT of mesophilic digestion, thermophilic digestion was considerably advantageous below this HRT. Thermophilic digestion produced smaller amount of sludges which had significantly higher settling velocity and lower specific resistance. Reaction rates also clearly demonstrated temperature and HRT effects on digestion. It was also found that gas production rates increased linearly with increasing reaction rates regardless of temperature and their relationships were almost identical at mesophilic and thermophilic temperature.

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Cost Estimation of Intermittent Aerobic Digestion (간헐포기소화의 비용 평가)

  • Kim, Woon Joong;Kim, Seong Hong;Kim, Hee Jun
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.1B
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    • pp.113-118
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    • 2006
  • Cost estimation of an intermittent aerobic digestion technology was carried out in this study. Aeration ratio is one of the most important design factors and it affects installation and power consumption cost. For the purpose, digestion efficiency was fixed at 35% of SS reduction and the reactor type was assumed a 2-chamber sequencing batch reactor (SBR). Installation cost and power consumption cost were evaluated and converted in terms of present value that could reflect the rate of discount and the rate of economic growth. The lower aeration ratio needs higher installation cost but lower power consumption cost. From the point of only installation cost, conventional aerobic digestion is cheaper than intermittent aerobic digestion. But intermittent aerobic digestion is better economical for more than 10 years of estimated service life. The optimal aeration ratio was dependent on the service life and it was lower as the estimated service life increased. For the 45 years as the service life, the optimal aeration ratio was estimated 0.3 and the total cost was 64% of the conventional aerobic digestion.

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Analysis of germanium in rock and sediment by ICP/MS after ammonium bifluoride(NH4HF2) digestion (이플루오린화 암모늄 시료분해 및 ICP/MS에 의한 암석 및 퇴적물 중 게르마늄 분석)

  • Eum, Chul Hun;Choi, Won Myung
    • Analytical Science and Technology
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    • v.26 no.6
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    • pp.375-380
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    • 2013
  • Ammonium biflouride ($NH_4HF_2$) digestion was studied for germanium analysis in rock and sediment by inductively coupled plasma mass spectrometry (ICP/MS). QLO-1 and SDO-1 are used for reference materials from USGS. Sediment, basalt and ball clay for GeoPT were chosen as real samples. The loss of germanium in open vessel digestion was well known which can be caused by easy transformation to volatile compounds. But ammonium bifluoride digestion could suppress loss of germanium in open vessel digestion. Germanium recovery was not influenced by hydrogen peroxide with ammonium bifluoride digestion. Furthermore, the new method was simple and rapid in germanium analysis by ICP/MS. MDL(method detection limit) was 0.015 ${\mu}g/g$ and germanium recovery was 106~128%.

A Study on the Effect of Energy Saving with Newly Implemented Vertical Circulating Tray Mixer in Anaerobic digester (혐기성 소화조의 에너지 효율 향상을 위한 수직 왕복형 교반기 적용에 관한 연구)

  • Joo, Yoon-Sik;Son, Guntae;Bae, Youngjun;Park, Jungsoo;Lee, Seunghwan
    • Journal of Korean Society of Water and Wastewater
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    • v.31 no.1
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    • pp.13-19
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    • 2017
  • Relatively low efficiency in anaerobic digestion process is mainly caused by unproper mixing method. In this study, tray motion type agitator was applied in actual anaerobic digestion tank in order to improve the digestion efficiency, equalize the flow velocity distribution and energy saving. The impeller of tray motion type agitator was reciprocated vertically. Gas lift type agitator and tray motion type agitator appears almost same mixing efficiency include digestion rates. However, tray motion type agitator have shown that lower energy consumption compared to the conventional gas lift type agitator. Implementation of tray motion type agitator in the anaerobic digestion tanks contributed to the stabilization of mixing environment, efficiency and energy efficiency of the tank.

Considerations of Acid Decomposition System for the Analysis of Heavy Metals in Packaging-grade Paper (포장용지류에서의 중금속 분석을 위한 산분해 전처리 방법의 탐색)

  • Lee, Tai-Ju;Ko, Seung-Tae;Kim, Hyoung-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.43 no.1
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    • pp.65-73
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    • 2011
  • The fibrous raw materials in packaging-grade paper production in Korea were mainly obtained from waste paper. The use of recycled paper has both positive and negative impacts in papermaking process. The primary positive impacts are the environmental protection and manufacturing cost reduction, and the negative impacts are the quality reduction in paper quality and the accumulation of heavy metals and other pollutants in wet- and dry-end process. This study was carried out to consider the optimum acid decomposition system with the highest recovery rate for the analysis of heavy metals in packaging-grade paper. The open digestion system using Kjeldahl apparatus and the closed digestion system using microwave oven for decomposing the organic materials in paper were compared. In both open and closed digestion method, the combination of nitric acid, hydrochloric acid and hydrogen peroxide showed higher recovery rate than using only nitric acid alone because the presence of Cl- ions in hydrochloric acid stabilizes ligand formation with metal ions. KOCC was observed to have the highest heavy metal content among the recycled paper samples. The heavy metal contents decomposed with the closed digestion system were relatively higher than with open digestion system.

Effects of Guanidination with Trypsin, Lys-C, or Glu-C Digestion on Mass Spectrometric Signal Intensity and Protein Sequence Coverage

  • Han, Hye-Sun;Nho, Seon-Ho;Lee, Ae-Ra;Kim, Jeong-Kwon
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1527-1534
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    • 2010
  • The conventional peptide modification process of guanidination, in which the amino groups of lysine residues are converted to guanidino groups using O-methylisourea to create more basic homoarginine residues, is often used to improve the signal intensity of lysine-containing peptides in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Here, we used three different protease enzymes (trypsin, Lys-C, and Glu-C) to evaluate the effects of guanidination on the MS signals of two enzymatically digested proteins. Horse heart myoglobin and bovine serum albumin were guanidinated either before or after digestion with trypsin, Lys-C, or Glu-C. The resulting peptides were subjected to MALDI-MS, and signal intensities and sequence coverage were systematically evaluated for each digest. Guanidination prior to Glu-C digestion improved sequence coverage for both proteins. For myoglobin, guanidination before enzymatic digestion with trypsin or Lys-C also enhanced sequence coverage, but guanidination after enzymatic digestion enhanced sequence coverage only with Lys-C. For albumin, guanidination either before or after Glu-C digestion increased sequence coverage, whereas pre- or post-digestion guanidination decreased sequence coverage with trypsin and Lys-C. The amino acid composition of a protein appears to be the major factor determining whether guanidination will enhance its MALDI-MS sequence coverage.

In Vitro Digestibility of Rice and Barley in Forms of Raw Flour and Cooked Kernels

  • Han, Jung-Ah;Jang, Su-Hae;Lim, Seung-Taik
    • Food Science and Biotechnology
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    • v.17 no.1
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    • pp.180-183
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    • 2008
  • Digestion properties of 3 types of cereals, white rice, brown rice, and barley, were measured after cooking or grinding. Regardless of the processing methods, white rice showed the highest rate and the greatest extent of digestion, whereas barley showed the lowest values. During the early digestion period, cooked white rice kernels had a larger k (kinetic constant) value than uncooked white rice flour, indicating that cooking induced faster digestion than grinding. In the case of brown rice and barley, the cell wall in cooked kernels remained intact and resulted in a lower k values than those of uncooked flour. However, after 3 hr of digestion, the total digestion extent was greater for the cooked brown rice and barley than that for uncooked flours. The high content of slowly digestible starch (SDS) in cooked brown rice and barley might be due to the starch fraction which was protected by the cell wall. The resistant starch (RS) content, however, was greater for the uncooked flours than that for cooked kernels. The cooked kernels of 3 cereal samples tested showed higher glycemic index (GI) values than the uncooked flours.