• Title/Summary/Keyword: aerobic-anaerobic conditions

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Preparation and Characteristics of Immobilized Sludge by the PAA Entrapment Method (PAA 포괄법에 의한 고정화 슬러지의 제조 및 특성에 관한 연구)

  • 최석순
    • Journal of Environmental Health Sciences
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    • v.28 no.3
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    • pp.49-54
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    • 2002
  • This study was conducted to evaluate the feasibility and characteristics of poly acrylamide (PAA) immobilized sludge as a microbial entrapment bead for wastewater treatment. In the PAA method of immobilized sludge, it was found that the optimum acrylamide concentration for actual wastewater treatment was to be 12%. When the sequencing batch reactor (SBR) was operated during 30 days, removal efficiencies of TOC and phosphate was 95% and 70ft, respectively. From this research, repeated cycle of anaerobic and aerobic conditions is required to enhance the removal of TOC and phosphate. During the operation, immobilized cells could be used without being disrupted.

The effects of organic materials on microbial mediation of arsenic. in contaminated sediment

  • Lee Jong-Un;Lee Sang-Woo;Kim Kyoung-Woong
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.532-535
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    • 2003
  • Indigenous bacterial mediation of As in contaminated sediment after biostimulation with a variety of carbon sources was investigated under aerobic and anaerobic conditions. Under the aerobic condition with lactate supply, indigenous bacteria increased the amount of total As extracted from the sediment and most dissolved As existed as As(V). Under the anaerobic, glucose-supplied condition, dissolved As diminished with time likely due to production of As sulfide(s) and subsequent precipitation, which resulted from bacterial reduction of ${SO_4}^{2-}$. The results implied that bacterial natural attenuation of As in subsurface has a potential to be practically applied.

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Comparison of tdcA Expression Between Escherichia coli and Salmonella enterica Serovar Typhimurium

  • Kim, Min-Jeong;Lim, Sang-Yong;Ryu, Sang-Ryeol
    • Journal of Microbiology and Biotechnology
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    • v.21 no.3
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    • pp.252-255
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    • 2011
  • Both Escherichia coli (E. coli) and Salmonella enterica serovar Typhimurium (S. Typhimurium) have a tdc operon that encodes enzymes involved in a metabolic pathway for the degradation of L-serine and L-threonine. However, S. Typhimurium does not have the tdcR gene, which is a positive regulator in E. coli. In the present study, transcriptional analysis revealed that tdcA expression in E. coli is higher under anaerobic than aerobic growth conditions, but the opposite is true in S. Typhimurium. Interestingly, a tdcR mutant strain of E. coli showed a similar expression pattern to that observed in S. Typhimurium and was also induced by anaerobic shock. These results suggest that the induction of tdcA expression by anaerobic conditions is observable when tdcA expression is low owing to the absence of TdcR.

Biological Nutrient Removal by Enhancing Anoxic Phosphate Uptake (무산소 조건에서의 인섭취를 이용한 생물학적 영양염류 제거)

  • Lee, Dae Sung;Jeon, Che Ok;Park, Jong Moon
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.5
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    • pp.861-867
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    • 2000
  • The feasibility of simultaneous phosphorus and nitrogen removal by enhancing anoxic phosphorus uptake was investigated in a sequencing batch reactor (SBR). By introducing an anoxic phase into an anaerobic-aerobic SBR (AO SBR), significant amounts of denitrifying phosphorus accumulating organisms (DPAOs) which can utilize nitrate as electron acceptor could be accumulated in the reactor (anaerobic-aerobic- anoxic-aerobic SBR, $(AO)_2$ SBR). A direct comparison of phosphorus uptake rate under anaerobic and aerobic conditions showed that the fraction of DPAOs in P-removing sludge were increased from 10% in the AO SBR to 64% in $(AO)_2$ SBR. The $(AO)_2$ SBR showed stable phosphorus and nitrogen removal efficiency: average removal efficiencies of TOC, total nitrogen, and phosphorus were 92%, 88%, and 100%. respectively. Results of the $(AO)_2$ SBR operation and batch tests showed that nitrite (up to 10 mg-N/L) was not detrimental to anoxic phosphorus uptake and could serve as good electron acceptor like nitrate.

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Laboratory-scale Microcosm Studies in Assessing Enhanced Bioremediation Potential of BTEX and MTBE under Various Electron Acceptors in Contaminated Soil

  • 오인석;이시진;장순웅
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.368-371
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    • 2003
  • Accidental release of petroleum products from underground storage tank(USTs) is one of the most common causes of groundwater contamination. BTEX is the major components of fuel oils, which are hazardous substances regulated by many nations. In addition to BTEX, other gasoline consituents such as MTBE(methyl-t-buthyl ether), anphthalene are also toxic to humans. Natual attenuation processes include physic, chemical, and biological trasformation. Aerobic and anaerobic biodegradation are believed to be the major processes that account for both containment of the petroleum-hydrocarbon plum and reduction of the contaminant concentrations. Aerobic bioremediation has been highly effective in the remediation of many fuel releases. However, Bioremediation of aromatic hydrocarbons in groundwater and sediments is ofen limited by the inability to provide sufficient oxygen to the contaminated zones due to the low water solubility of oxygen. Anaerobic processes refer to a variety of biodegradation mechanisms that use nitrate, ferric iron, sulfate, and carbon dioxide as terminal electron accepters. The objectives of this study was to conduct laboratory-scale microcosm studies in assessing enhanced bioremediation potential of BTEX and MTBE under various electron accepters(aerobic, nitrate, ferric iron, sulfate) in contaminated Soil. these results suggest that, presents evidence and a variety pattern of the biological removal of aromatic compounds under enhanced nitrate-, Fe(III)-, sulfate-reducing conditions.

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Effects of Standardized Ginseng Extract and Exercise Training on Aerobic and Anaerobic Exercise Capacities in Humans (표준화된 인삼추출물과 운동훈련이 사람의 호기적 및 혐기적 운동능력에 미치는 영향)

  • Pipat , Cherdrungsi;Kanyarat , Rungroeng
    • Journal of Ginseng Research
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    • v.19 no.2
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    • pp.93-100
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    • 1995
  • This study was undertaken to determine whether administration of a standardized gindeng extract at 300 mg.$d^1$ for 8 weeks could enhance maximum aerobic and anaerobic exercise capabilities and whether any changes of such effects can be occurred when exercise training was added. Forty-one male university students were randomly divided into four groups as ginseng-untrained (GU, n=10), ginseng-trained (GT, n=10), placebo-untrained (PU, n=10), and placebo-trained (PT, n=11). The trained groups underwent 8 weeks of aerobic exercise at 65% of individual's maximum oxygen consumption ($Vo_2$ max) for 30 min.$d^1$, 3d.$wk^1$. Prior to and at the end of experiment, $Vo_2$ max, anaerobic power (AP), anaerobic capacity (AC), and leg muscle strength were determined and some physiological parameters related to $Vo_2$ max were measured. Initially, all subject groups did not differ in average $Vo_2$ max (range 45.9 to 47.9 ml/.kg-1.min-1). After 8 weeks, the $Vo_2$ max increased significantly from the initial level by 12.6% in group GU, 14.5% in group PT, and 24.5% in group GU which was significantly higher than group GU but not group PT. Changes in all measured parameters related to $Vo_2$ max were similar among the subject groups except group PU. Both the AP and the AC were significantly increased in all subject groups (range +3.6 to +13.1% above initial for the AP and +4.4 to) 8.955 above initial for the AC) but the higher changes were found for the AP in groups PT and GU, and for the AC in grouts PT, when compared with group PU. No significant differences in the two anaerobic variables were observed between group GT and the other groups of subjects. Leg strength was also significantly enhanced over group PU in groups PT, GU and GT. There were no significant differences among the latter three subject groups. As a result of these findings, it was concluded that under the conditions of this study ginseng administration at the prescribed dose exhibited the training-like effects on $Vo_2$ max as well as anaerobic power and leg muscle strength but no clear synergistic action on these physical fitness variables occurred when both g inseng administration and exercise training were combined.

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Possibility of aerobic stabilization technology for reducing greenhouse gas emissions from landfills in Korea (국내 폐기물매립지 온실가스 감축을 위한 호기성 안정화 공법의 적용 가능성)

  • Ban, Jong-Ki;Park, Jin-Kyu;Kim, Kyung;Yoon, Seok-Pyo;Lee, Nam-Hoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.23 no.4
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    • pp.40-51
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    • 2015
  • This study is to estimate the viability of aerobic stabilization technology for reducing greenhouse gas (GHG) emissions from landfills in Korea. In this study, methane emissions were estimated by applying Landfill gas estimation model (LandGEM) to Y landfill in Korea. By comparison of an anaerobic condition (baseline) and an aerobic condition, the amount of $CO_2eq$ savings was calculated. The $CO_2eq$ savings take place inside the landfilled waste during aeration due to the conversion of previously anaerobic biodegradation to aerobic processes, releasing mainly $CO_2$. It was demonstrated that 86.6% of the total GHG emissions occurring under anaerobic conditions could be reduced by aerobic stabilization technology. This means the aerobic stabilization technology could reduce environmental contamination through early stabilization and GHG emissions considerably at the same time. Therefore, the aerobic stabilization technology is one of the optimal technologies that could be employed to domestic landfill sites to achieve sustainable landfill.

Effects of Bottom Ash Amendment on Soil Respiration and Microbial Biomass under Anaerobic Conditions (혐기조건에서 석탄바닥재가 토양호흡량 및 미생물 생체량에 미치는 영향)

  • Park, Jong-Chan;Chung, Doug-Young;Han, Gwang-Hyun
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.2
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    • pp.260-265
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    • 2012
  • Soil respiration under flooded conditions is considered to be very small compared with aerobic soil respiration of soil organic matter. However, anaerobic decomposition of soil plays a key role in carbon cycling in flooded ecosystems. On the other hand, coal-ash wastes, such as fly ash and bottom ash, are known to function as a soil amendment for mitigating $CO_2$ emission and enhancing carbon sequestration in up land soils. In this study, we investigated bottom ash as a soil amendment for mitigating $CO_2$ emission, and thus enhancing carbon sequestration under anaerobic conditions. We observed that amendment of bottom ash without external organic source led to significant reduction in $CO_2$ emission rate and in total cumulative $CO_2$ emission flux over the incubation period, which was proportional to the amount of bottom ash applied. We also found that soil microbial biomass increased in response to application of bottom ash. These results suggest that bottom ash can be utilized to store $CO_2$ as a stable soil organic carbon in flooded ecosystems, as in aerobic situations.

The Assimilability of Glucose and Xylose in Rhodopseudomonas sp. K-7. (Rhodopseudomonas sp. K-7 의 당자화성)

  • Kim, Yong-Hyo;Bae, Moo
    • Microbiology and Biotechnology Letters
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    • v.13 no.2
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    • pp.169-172
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    • 1985
  • The assimilability of glucose and xylose of Rhodopseudomonas K-7, whose hydrogen evolution has been characterized previously, was investigated under the anaerobic photosynthetic and the aerobic dark conditions. This organism is able to grow well in the medium containing glutamate and malate as organic substances under the anaerobic light condition. However, the substitution of glucose for malate retarded the growth rate, while the addition of glucose to the seed culture remarkably promoted the utilization of glucose added in the main culture. Optimal glucose concentration in the seed culture to induce glucose assimilability of the organism was around the concentration of 60 mM of glucose. Then, the seed culture grown in the medium containing 60 mM of glucose were inoculated in the medium containing 10, 20, 30, 60 and 100 mM of glucose respectively. The results were revealed that the consumable content of glucose was limited even though the high concentrations of glucose was contained in the medium. The consumption of considerable amount of glucose was observed when cultured under the aerobic dark conditions than the anaerobic illuminated conditions.

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A Study on Characteristics of Aerobic Liquid-Composting using a Micro Air Diffusion and a Mixer System (미세기포와 교반을 이용한 호기성 액비특성에 관한 연구)

  • Gu, Bon-Woo;Oh, Dae-Min;Lee, Young-Shin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.4
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    • pp.1354-1360
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    • 2010
  • The purpose of this study is to analyze the behavior of swine slurry wastewater from bogen, in the treatment of Aerobic Liquid-Composting treatment by Aerobic Liquid-Composting using a mixer and Micro Air Diffusion pH level was at the beginning and its rise was seemingly related to VFA. It appears that removal of BOD and COD are more effective by Aerobic than by Anaerobic. In terms of removal efficiency, it shows 70.9% of BOD and 39% of COD in M.A+Mix and 67.8% of BOD and 19% of COD in M.A. $NH_3-N$ decreases in all conditions, which is caused by both the characteristic of nitrogen and the rise of pH. $NO_3-N$ increases in all conditions. It is judged that the accumulation of $NO_3-N$ affects the reduction of the ratio of denitrification. In the result of the analysis of Manure in swine slurry of liquified fertilizer ingredients, content of Manure in swine slurry of liquified fertilizer ingredients in aerobic conditions (M.A+Mix) is higher than anaerobic conditions.