• Title/Summary/Keyword: Denitrification Rate

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현장 Single Well Push-Pull 실험을 통한 탈질산화반응 각 단계의 반응속도 측정

  • Yeong, Kim;Jin Hun, Kim;Bong Ho, Son;Seong Uk, Eo
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.04a
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    • pp.77-82
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    • 2004
  • Quantifying rates of microbial processes under subsurface conditions is difficult, and is most commonly approximated by laboratory studies using aquifer materials. In this study a single-well, 'push-pull' test method is adapted for the in situ determination of denitrification rates in groundwater aquifers. The rates of stepwise reduction of nitrate to nitrite, nitrous oxide, and molecular nitrogen were determined by performing a series of push-pull tests at an experimental well field of Korea University. A single Transport Test, one Biostimulation Test, and four Activity Tests were conducted for this study. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide (a conservative tracer), fumarate (a carbon and/or source), and nitrate (an electron acceptor). At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the solutes prior to biostimulation. Biostimulation tests were conducted to stimulate the activity of indigenous heterotrophic denitrifyinc microorganisms. Biostimulation was detected by the simultaneous production of carbon dioxide and nitrite after each injection. Activity tests were conducted to quantify rates of nitrate, nitrite, and nitrous oxide reduction. Estimated zero-order degradation rates decreased in the order nitrate '||'&'||'gt; nitrite '||'&'||'gt; nitrous oxide. The series of push-pull tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibi1ity assessments for in situ denitrification in nitrate-contaminated aquifers.

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Greenhouse gases emission from aerobic methanotrophic denitrification (AeOM-D) in sequencing batch reactor

  • Lee, Kwanhyoung;Choi, Oh Kyung;Lee, Jae Woo
    • Membrane and Water Treatment
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    • v.8 no.2
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    • pp.171-184
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    • 2017
  • This study presents the effect of hydraulic retention time (HRT) on the characteristics of emission of three major greenhouse gases (GHGs) including $CH_4$, $CO_2$ and $N_2O$ during operation of a sequencing batch reactor for aerobic oxidation of methane with denitrification (AeOM-D SBR). Dissolved $N_2O$ concentration increased, leveled-off and slightly decreased as the HRT increased from 0.25 to 1d. Concentration of the dissolved $N_2O$ was higher at the shorter HRT, which was highly associated with the lowered C/N ratio. A longer HRT resulted in a higher C/N ratio with a sufficient carbon source produced by methanotrophs via methane oxidation, which provided a favorable condition for reducing $N_2O$ formation. With a less formation of the dissolved $N_2O$, $N_2O$ emission rate was lower at a longer HRT condition due to the lower C/N ratio. Opposite to the $N_2O$ emission, emission rates of $CH_4$ and $CO_2$ were higher at a longer HRT. Longer HRT resulted in the greater total GHGs emission as $CO_2$ equivalent which was doubled when the HRT increased from 0.5d to 1.0 d. Contribution of $CH_4$ onto the total GHGs emission was most dominant accounting for 98 - 99% compared to that of $N_2O$ (< 2%).

Effect of addition of a catalystic layer on Denitrification System efficiency in a 500 MW Coal-fired Power Plant (500 MW 석탄화력발전소 촉매단추가에 따른 탈질설비 효율에 미치는 영향)

  • Lee, Sang Soo;Moon, Seung-Jae
    • Plant Journal
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    • v.17 no.1
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    • pp.58-66
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    • 2021
  • The government has recently come up with a policy to tighten regulations on air pollutant emissions due to public concerns over the emission of pollutants such as fine dust. The coal-fired power plant is speeding up the improvement of the performance of environmental facilities, and this paper deals with the cases of performance improvement by adding a catalyst to the 500 MW standard coal-fired power DeNox system, and examines the change in the performance factors according to the addition of catalysts and the efficiency of NOx removal. The DeNOx efficiency before and after improvement increased from 80% to 88%, and the conversion rate of SO2/SO3, ammonia slip which are performance factors satisfied the design assurance value, but exceeded the design assurance value for differential pressure. At the same time, the ammonia slip concentration and differential pressure items increased as the NOx removal efficiency increased, resulting in the need for management and improvement.

Acid Fermentation Characteristic of Food Wastes According to the Organic Loading Rate (유기물부하에 따른 음식물찌꺼기의 산발효 특성)

  • Park, Jin-Sik;Ahn, Chul-Woo;Jang, Seong-Ho
    • Journal of Environmental Science International
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    • v.15 no.10
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    • pp.975-982
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    • 2006
  • This study has been conducted to optimum operating conditions for effective acid fermentation according to OLR(organic loading rate) in the mesophilic and thermophilic acid fermentation process. The results are summarized as follows. In order to obtain reasonable acid fermentation efficiency in performing acid fermentation of food wastes in thermophilic condition, organic loading rate was required below 20 gVS/L.d. As $SCOD_{Cr}/TKN,\;SCOD_{Cr}/T-P$ of thermophilic acid fermented food wastes In organic loading rate 20 gVS/L.d were 18.9, 73.4 respectively, it was possible to utilize as external carbon source for denitrification in sewage treatment plant after solid-liquid separation as well as co-digestion of fermented food wastes and sewage sludge.

A Study on the Biological Nitrogen Removal of the Chemical Fertilizer Wastewater Using Jet Loop Reactor (Jet Loop 반응기를 이용한 화학비료폐수의 생물학적 질소제거 연구)

  • Seo Jong-Hwan;Lee Chul-Seung
    • Journal of Environmental Science International
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    • v.14 no.2
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    • pp.157-165
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    • 2005
  • This study was conducted to determine optimum design parameters in nitrification and denitrfication of chemical fertilizer wastewater using pilot plant, Jet Loop Reactor. The chemical fertilizer wastewater which contains low amounts of organic carbon and has a high nitrogen concentration requires a post-denitrfication system. Organic nitrogen is hydrolyzed above $86\%$, and the concentration of organic nitrogen was influent wastewater 126mg/L and of effluent wastewater 16.4mg/L, respectively. The nitrification above $90\%$ was acquired to TKN volumetric loading below $0.5\;kgTKN/m^3{\cdot}d$, TKN sludge loading below $0.1\;kgTKN/kgVSS{\cdot}d$ and SRT over 8days. The nitrification efficiency was $90\%$ or more and the maximum specific nitrification rate was $184.8\;mgTKN/L{\cdot}hr$. The denitrification rate was above $95\%$ and the concentration of $NO_3-N$ was below 20mg/L. This case was required to $3\;kgCH_3OH/kgNO_3-N$, and the effluent concentration of $NO_3^--N$ was below 20mg/L at $NO_3^--N$ volumetric loading below $0.7\;kgNO_3^--N/m^3{\cdot}d$ and v sludge loading below $0.12\;kgNO_3^-N/kgVSS{\cdot}d$. At this case, the maximum sludge production was $0.83\;kgTS/kgT-N_{re}$ and the specific denitrfication rate was $5.5\;mgNO_3-N/gVSS{\cdot}h$.

Biological Nitrogen and Phosphorus Removal Characteristics on Organic Material and Nitrate Loadings in SBR Process (연속회분식반응조에서 유기물 부하와 질산염농도에 따른 생물학적 질소 및 인 제거 특성)

  • Kim, I-Tae;Lee, Hee-Ja;Kim, Kwang-Soo;Bae, Woo-keun
    • Journal of Korean Society on Water Environment
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    • v.20 no.6
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    • pp.571-576
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    • 2004
  • Since anaerobic/anoxic/oxic process, which is a typical mainstream biological nitrogen and phosphorus removal process, utilizes influent organic matter as an external carbon source for phosphorus release in anaerobic or anoxic stage, influent COD/T-P ratio gives a strong influence on performance of phosphorus removal process. In this study, a bench scale experiment was carried out for SBR process to investigate nitrogen and phosphorus removal at various influent COD/T-P ratio and nitrate loadings of 23~73 and 1.6~14.3g $NO_3{^-}-N/kg$ MLSS, respectively. The phosphorus release and excess uptake in anoxic condition were very active at influent COD/T-P ratios of 44 and 73. However, its release and uptake was not obviously observed at COD/T-P ratio of 23. Consequently, phosphorus removal efficiency was decreased. In addition, the phosphorus release and uptake rate in anoxic condition increased as the nitrate loading decreased. Specific denitrification rate had significantly high correlation with organic materials and nitrate loadings of the anoxic phase too. The rate of phosphorus release and uptake in the anoxic condition were $0.08{\sim}0.94kg\;S-P/kg\;MLSS{\cdot}d$ and $0.012{\sim}0.1kg\;S-P/kg\;MLSS{\cdot}d$, respectively.

Recycled packed-bed reactor for efficient denitrification (재순환 충전탑식 반응기를 이용한 효율적 탈질)

  • 김성홍;송승훈;박재연;유영제
    • KSBB Journal
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    • v.19 no.2
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    • pp.154-158
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    • 2004
  • Recycled packed-bed reactor emploring immobilized microorganism was suggested in this paper for efficient denitrification. In the batch reactor, the effects of initial oxidation-reduction potential and nitrate concentration on denitrification were investigated. As the initial oxidation-reduction potential was decresed to -70 mV from +40 mV, the removal rate of nitrate was increased to 3.33 from 1.25 m9 NO$_3$$\^$-/-N/min under the experimental conditions. As the initial nitrate-N concentraion was increased to 200 mg/l, the removal rate of nitrate was proportional to the concentration of nitrate. When the concentration of nitrate-N was 400 mg/min, nitrite was detected, and when the initial nitrate-N concentration was reached at 1,000 mg/l, it took longer time for the complete nitrate removal. In order to decrease the initial oxidation-reduction potential and the nitrate-N concentration in the feed stream, the effluent was recycled to the influent stream in the packed-bed reactor. In the case of recycling, the initial oxidation-reduction potential was decreased to 30 mV from 150 mV, and the initial nitrate concentration could be decreased to 85 from 120 mg NO$_3$$\^$-/-N/l. As the result of recycling, the removal rate of nitrate was increased to 91.7% from 49.2%.

Denitrification Performance and Bacterial Community Structure of Methanol and Mixed Carbon Sources (메탄올과 혼합 외부탄소원의 탈질성능과 박테리아 군집 비교)

  • Suin Park;Junbeom Jeon;Minkyu Choi;Sungjin Kim;Sanghun Lee;Taeho Lee;Sanghyun Jeong;Hyokwan Bae
    • Journal of Korean Society on Water Environment
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    • v.39 no.1
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    • pp.61-75
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    • 2023
  • Denitrifying bacteria convert nitrate to nitrogen gas using an external carbon source as an electron donor. The external carbon source affects the denitrification performance and bacterial community structure. Although methanol is a cheap and effective external carbon source, the addition of diverse carbon sources may improve the total nitrogen removal rate and biomass characteristics, such as settleability. In this study, denitrifying reactions were performed using solely methanol and mixed carbon sources of methanol, glucose, and acetate in a sequencing batch reactor. The denitrifying reactor using methanol resulted in a total nitrogen removal rate of 0.39 ± 0.025 kg-N/m3-day while the suspended biomass transformed into dark brown granules. Methyloversatilis discipulorum had the highest predominance at 43.84%. The individual denitrifying biomasses, which were separately enriched with methanol, glucose, and acetate, showed the same total nitrogen removal performance of 0.39 ± 0.016 kg-N/m3-day. However, the addition of mixed carbon sources showed an improved total nitrogen removal rate of 0.42 ± 0.043 kg-N/m3-day, with the domination of Candidatus Saccaribacteria at 25.61%. The denitrifying granules turned pale yellow color. Influent COD/NO3--N ratios of 3.5, 5, and 7.5 exhibited COD/NO3--N consumptions of 4.3 ± 0.4, 4.4 ± 0.8, and 5.2 ± 0.7, and the consistent predominance of Candidatus Saccharibacteria.

Isolation and Characteristics of Denitrifying Pseudomonas CW4 (탈질균 Pseudomonas CW4의 분리 및 특성)

  • Hwang, Seon-Hyeon;Lee, Yeong-Ho;Jo, Mu-Hwan
    • KSBB Journal
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    • v.14 no.5
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    • pp.616-620
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    • 1999
  • Ten denitrifying bacteria, which were identified as Pseudomonas sp., were isolated from Winogradsky columns. The most effective denitrifying bacterium was named as Pseudomonas CW4, which was cultivated at anoxic condition. The optimal growth temperature and pH were 3$0^{\circ}C$ and 6-8, respectively. The effect of carbon concentration and agitator speed on the rate of denitrification were very low. 100% of NO$_3$-N was removed after 15 hrs when initial concentration of NO$_3$-N was 142.5 mg/L.

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Study on Removal of DOC for Effluent from Nitrification and Denitrification Process with Zeolite by Combined Process of Coagulation and UF Membrane (제올라이트를 첨가한 질산화 탈질공정에서 응집과 UF공정을 이용한 처리수내 용존 유기물질 제거 연구)

  • Han, Jang Hyuk;Yoon, Tai Il;Cho, Kyung Chul;Song, Jea Yong
    • Journal of Korean Society of Water and Wastewater
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    • v.19 no.5
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    • pp.537-546
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    • 2005
  • This study was carried out to evaluate EPS and SMP variation of sludge and effluent in nitrification and denitrification process with zeolite addition, a possible reduction of effluent DOC by URC(Ultra Rapid Coagulation) process. As a biological wastewater treatment result, EPS formation of both aeration and anoxic sludges are not affect by SRT variation. However, EPS concentration of sludges is higher in aeration tank than in anoxic tank by 6~8 mg EPS/ g VSS. Linear relationship between SMP to DOC indicates that SMP of bulk solution contributes to most of the biological treatment effluent DOC. DOC and turbidity removal efficiency was more improved with URC process than in a conventional coagulation. For pretreatment of UF filtration DOC removal was advanced by URC process than only UF filtration.