• 제목/요약/키워드: digestion

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슬러지 저감을 위한 혐기성 소화조 개선에 관한 연구 (A Study of the Improvement in an Anaerobic Digester for Sludge Reduction)

  • 김홍석;이태진
    • 대한환경공학회지
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    • 제33권7호
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    • pp.516-522
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    • 2011
  • 국내에서 운영중인 혐기성 소화조의 가장 큰 문제점은 낮은 소화효율이며, 이에 대한 원인은 낮은 유기물 투입농도, 소화조내의 낮은 교반 효율, 잉여슬러지의 난분해성 등이다. 본 연구에서는 혐기성 소화설비의 효율성을 높이기 위하여 기존의 혐기성 소화 시스템에 농축 및 교반, 오존 가용화 설비를 설치하고, 기존의 2단 소화조에서 단단소화조로 개선함으로서 소화효율 및 바이오가스의 발생량을 증대 시키고자 하였다. 이러한 개선을 통하여 농축시스템의 슬러지 농도는 2.6배 향상되었음을 확인하였으며, 농축효율은 3.0배 증가한 것으로 나타났다. 또한, 기계식 교반으로 사공간이 줄어들었음을 확인하였으며, 혐기성 소화조 내 소화가스 발생량도 평균 $193.8m^3$/일에서 평균 $386.0m^3$/일로 향상된 것을 확인하였다. 소화효율은 평균 47.6%에서 54.6%로 향상되어진 것으로 나타났으며, VS제거당 소화가스 발생량은 평균 $0.30Nm^3/kg$ VS removal에서 $0.42Nm^3/kg$ VS removal로 증대되어진 것으로 나타났다.

In Situ Digestion Kinetics of Mottgrass (Pennisesetum Purpureum) With or Without Supplemental Legume at Two Levels by Buffalo Calves

  • Sarwar, M.;Mahr-un-Nisa, Mahr-un-Nisa
    • Asian-Australasian Journal of Animal Sciences
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    • 제12권3호
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    • pp.371-375
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    • 1999
  • The present study was conducted to evaluate the mottgrass alone and in combination with berseem (Trifolium alexandrinum) at different intake levels to determine the lag time, rate and extent of digestion of DM and NDF of mottgrass. Four ruminally cannulated buffalo calves were used in a $4{\times}4$ Latin Square Design with $2{\times}2$ factorial arrangement of treatments. The two factors were forage intake levels (ad libitum versus restricted) and forage source (mottgrass versus mottgrass plus 25% berseem). Four dietary treatment consisted of 1) ad libitum mottgrass, 2) restricted feeding of mottgrass, 3) ad libitum mottgrass plus berseem with a ratio of 3:1 and 4) restricted mottgrass plus berseem in a ratio of 3:1 Calves fed ad libitum mottgrass supplemented with 25% berseem consumed 25% more DM and 15 % more NDF than those fed mottgrass only. The in situ DM digestibility, the lag time and extent of digestion were not affected by intake level. However, rate of disappearance was greater in restricted fed animals than those fed ad libitum. This increased rate could be due to greater concentration of fibrolytic bacteria in restrict fed animals. The DM digestibility was greater (64.1%) in calves fed mottgrass supplemented with 25% berseem than those fed mottgrass only (57.7%). The reduced mottgrass DM digestion may be due to its higher NDF contents. The NDF digestibility, the lag and extent of NDF digestion were not affected by varying intake levels. However, rate of digestion of NDF was higher in restricted fed animals than those of ad libitum fed animals. The NDF digestibility was greater (58.4%) in calves fed mottgrass supplemented with 25% berseem than those fed mottgrass (48.7%) only.

증산제를 통한 혐기소화율 개선 및 슬러지 감량 활용방안 (Application Plan of Sludge Reduction and Improvement of Ananerobic Digestion Rate Using VFAs from Food Waste)

  • 이광헌;김길수;손병권;최찬섭;조진우;신재훈;정태영
    • 유기물자원화
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    • 제26권3호
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    • pp.47-54
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    • 2018
  • 본 연구는 음식물폐기물로부터 얻어진 증산제 용액을 농축슬러지와 함께 혐기소화조의 투입한 결과 혐기소화율 향상 및 슬러지 감량화를 살펴보았다. 혐기소화조에 증산제를 5%정도 농축슬러지와 함께 투입한 소화조의 메탄생성율이 약 2.7배 정도 높게 발생하였으며, 소화조내 TCOD 농도값이 약 2배 이상 높게 나타난 것은 투입된 농축슬러지의 감량화가 빠르게 진행됨을 알 수 있었다. 또한, 투입된 증산제로 인해 메탄생성효율에 크게 기여함을 간접적으로 알 수 있었다.

Methane Production Potential of Food Waste and Food Waste Mixture with Swine Manure in Anaerobic Digestion

  • Islam, Mohammad Nazrul;Park, Keum-Joo;Yoon, Hyung-Sun
    • Journal of Biosystems Engineering
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    • 제37권2호
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    • pp.100-105
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    • 2012
  • Purpose: Methane production potential in aerobic digestion was assessed according to feed to inoculum (F/I) ratio for food waste only, and mixing ratio of two materials for food waste and swine manure to give a basic data for the design of anaerobic digestion system. Methods: Anaerbic digestion test was performed using a lab scale batch reactor at $35^{\circ}C$ for six different feed to inoculum (F/I) ratios (0.50, 0.72, 1.14, 1.50, 2.14 and 3.41), three food waste to swine manure ratios (100:0, 60:40 and 40:60) with two different loading concentrations (10g VS/L and 30g VS/L). Results: For food waste only, the highest biogas yield of 1008 mL/gVS was obtained at 0.50 of F/I. For the co-digestion of food waste and swine manure mixture, the highest biogas yield of 1148 mL/gVS was obtained at a mixing ratio of 40:60 with loading concentration of 10g VS/L. Conclusions: F/I ratio for the food waste only, mixing ratio of food waste and swine manure, and co-substrate loading rate affected the biogas production rate. For the low loading rate, there was not so much difference according to the mixing ratio of food waste and swine manure, but for the high loading rate higher biogas yield was acquired for the co-digestion of food waste and swine manure than for the food waste alone (mixing ratio, 100:0).

Low Protein Digestibility of Beef Puree in Infant In Vitro Digestion Model

  • Lee, Seonmin;Jo, Kyung;Hur, Sun Jin;Choi, Yun-Sang;Kim, Hyun-Joo;Jung, Samooel
    • 한국축산식품학회지
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    • 제39권6호
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    • pp.1000-1007
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    • 2019
  • This study investigated protein digestibility of beef puree in infant and adult in vitro digestion models. The simulated digestive juices for infant and adult were prepared. Protein digestibility of beef puree was calculated in the gastric and gastrointestinal compartments. The 10% trichloroacetic acid soluble nitrogen and α-amino group contents of gastric digesta were lower in the infant in vitro digestion model than those in the adult in vitro digestion model (p<0.05). In addition, the gastrointestinal digesta from the infant in vitro digestion model had lower value of the 10% trichloroacetic acid soluble nitrogen and α-amino group contents than those of the adult in vitro digestion model (p<0.05). The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the remarkable bands of actin and myosin light chain B were found in the digesta of beef puree from the infant in vitro digestion model. The results of this study revealed the lower protein digestibility of beef puree in infants compared to that in adults. Therefore, the development of ways to increase digestibility of meat protein can improve the nutritional quality of meat products for infants.

Sustainable anaerobic digestion of euphorbiaceae waste for biogas production: Effects of feedstock variation

  • Kamaruddin, Mohamad Anuar;Ismail, Norli;Fauzi, Noor Fadhilah;Alrozi, Rasyidah;Hanif, Mohamad Haziq;Norashiddin, Faris Aiman
    • Advances in environmental research
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    • 제10권1호
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    • pp.87-103
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    • 2021
  • Anaerobic digestion (AD) refers to the biological process which can convert organic substrates to biogas in the absence of oxygen. The aim of this study was to determine the capability of feedstock to produce biogas and to quantify the biogas yield from different feedstocks. A co-digestion approach was carried out in a continuous stirred tank reactor operated under mesophilic conditions and at a constant organic loading rate of 0.0756 g COD/ L.day, with a hydraulic retention time of 25 days. For comparison, mono-digestion was also included in the experimental work. 2 L working volumes were used throughout the experimental work. The seed culture was obtained from composting as substrate digestion. When the feedstock was added to seeding, the biogas started to emit after three days of retention time. The highest volume of biogas was observed when the seeding volume used for 1000mL. However, the lowest volume of biogas yield was obtained from both co-digestion reactors, with a value of 340 mL. For methane yield, the highest methane production rate was 0.16 L CH4/mg. The COD with yield was at 8.6% and the lowest was at 0.5%. The highest quantity of methane was obtained from a reactor of Euphorbiaceae peel with added seeding, while the lowest methane yield came from a reactor of Euphorbiaceae stems with added seeding. In this study, sodium bicarbonate (NaHCO3) was used as a buffering solution to correct the pH in the reactor if the reactor condition was found to be in a souring or acidic condition.

Three-step in vitro digestion model for evaluating and predicting fecal odor emission from growing pigs with different dietary protein intakes

  • Lo, Shih-Hua;Chen, Ching-Yi;Wang, Han-Tsung
    • Animal Bioscience
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    • 제35권10호
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    • pp.1592-1605
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    • 2022
  • Objective: The objective of this study was to select an effective in vitro digestion-fermentation model to estimate the effect of decreasing dietary crude protein (CP) on odor emission during pig production and to suggest potential prediction markers through in vitro and in vivo experiments. Methods: In the in vitro experiment, three diet formulations with different CP contents (170 g/kg, 150 g/kg, and 130 g/kg) but containing the same standardized ileal digestible essential amino acids (SID-EAA) were assessed. Each diet was evaluated by two different in vitro gastric-intestinal phase digestion methods (flask and dialysis), combined with fresh pig feces-ferment inoculation. Eighteen growing barrows (31.9±1.6 kg) were divided into three groups: control diet (180 g CP/kg, without SID-EAA adjustment), 170 g CP/kg diet, and 150 g CP/kg diet for 4 weeks. Results: The in vitro digestion results indicated that in vitro digestibility was affected by the gastric-intestinal phase digestion method and dietary CP level. According to the gas kinetic and digestibility results, the dialysis method showed greater distinguishability for dietary CP level adjustment. Nitrogen-related odor compounds (NH3-N, indole, p-cresol, and skatole) were highly correlated with urease and protease activity. The feeding study indicated that both EAA-adjusted diets resulted in a lower odor emission especially in p-cresol and skatole. Both protease and urease activity in feces were also closely related to odor emissions from nitrogen metabolism compounds. Conclusion: Dialysis digestion in the gastric-intestinal phase followed by fresh fecal inoculation fermentation is suitable for in vitro diet evaluation. The enzyme activity in the fermentation and the fecal samples might provide a simple and effective estimation tool for nitrogen-related odor emission prediction in both in vitro and in vivo experiments.

Influence of ruminal degradable intake protein restriction on characteristics of digestion and growth performance of feedlot cattle during the late finishing phase

  • May, Dixie;Calderon, Jose F.;Gonzalez, Victor M.;Montano, Martin;Plascencia, Alejandro;Salinas-Chavira, Jaime;Torrentera, Noemi;Zinn, Richard A.
    • Journal of Animal Science and Technology
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    • 제56권4호
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    • pp.14.1-14.7
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    • 2014
  • Two trials were conducted to evaluate the influence of supplemental urea withdrawal on characteristics of digestion (Trial 1) and growth performance (Trial 2) of feedlot cattle during the last 40 days on feed. Treatments consisted of a steam-flaked corn-based finishing diet supplemented with urea to provide urea fermentation potential (UFP) of 0, 0.6, and 1.2%. In Trial 1, six Holstein steers ($160{\pm}10kg$) with cannulas in the rumen and proximal duodenum were used in a replicated $3{\times}3$ Latin square experiment. Decreasing supplemental urea decreased (linear effect, $P{\leq}0.05$) ruminal OM digestion. This effect was mediated by decreases (linear effect, $P{\leq}0.05$) in ruminal digestibility of NDF and N. Passage of non-ammonia and microbial N (MN) to the small intestine decreased (linear effect, P = 0.04) with decreasing dietary urea level. Total tract digestion of OM (linear effect, P = 0.06), NDF (linear effect, P = 0.07), N (linear effect, P = 0.04) and dietary DE (linear effect, P = 0.05) decreased with decreasing urea level. Treatment effects on total tract starch digestion, although numerically small, likewise tended (linear effect, P = 0.11) to decrease with decreasing urea level. Decreased fiber digestion accounted for 51% of the variation in OM digestion. Ruminal pH was not affected by treatments averaging 5.82. Decreasing urea level decreased (linear effect, $P{\leq}0.05$) ruminal N-NH and blood urea nitrogen. In Trial 2, 90 crossbred steers ($468kg{\pm}8$), were used in a 40 d feeding trial (5 steers/pen, 6 pens/treatment) to evaluate treatment effects on final-phase growth performance. Decreasing urea level did not affect DMI, but decreased (linear effect, $P{\leq}0.03$) ADG, gain efficiency, and dietary NE. It is concluded that in addition to effects on metabolizable amino acid flow to the small intestine, depriving cattle of otherwise ruminally degradable N (RDP) during the late finishing phase may negatively impact site and extent of digestion of OM, depressing ADG, gain efficiency, and dietary NE.

혐기 소화 시 식물체 잔사 및 투입량에 따른 메탄 생산량 예측 (Predicting Methane Production on Anaerobic Digestion to Crop Residues and Biomass Loading Rates)

  • 신중두;홍승길;박상원;김현욱
    • 유기물자원화
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    • 제24권3호
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    • pp.75-82
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    • 2016
  • 본 연구의 목적은 농업에서 발생하는 식물체 잔사 종류별 투입비율에 따른 메탄 잠재 발생량을 예측하는 것이다. 바이오가스를 생산하기 위하여 보릿짚 및 유채대 등의 식물체 잔사를 다양한 투입율로 사용하여 세륨병에서 실험을 수행하였다. 표면 방법론의 운동방법을 통하여 메탄 생산은 Gomperz 수식에 적합한 것으로 나타났다. 중온소화 시 식물체 잔사별 바이오가스 생산에 있어, 최대생산량은 보릿짚 및 유채대 투입율 1%로 혐기소화 후 각각 6.8일에 37.2 mL/g과 7.5일에 28.0 mL/g로 나타났다. 중온소화 시 메탄 함량은 보릿짚 및 유채대 투입율 5%로 혐기소화 후 각각 5.5일에 61.7%와 3.4일에 75.0%로 가장 높게 관측되었다. 중온 소화시 최대 메탄 잠재발생량은 1% 보릿짚 투입율에서 159.59 mL/g 와 3% 유채대 투입율에서 156.62 mL/g로 산정되었다. 전반적으로 중온소화 시 바이오매스 투입율은 유채대 3% 및 보릿짚 1%를 투입하는 것이 적정 비율인 것으로 나타났다.