• Title/Summary/Keyword: Hydraulic retention time

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Effect of Hydraulic Retention Time (HRT) on the Hydrogen Production and Its Dynamic Characteristics in the Anaerobic Digestion Process Using Clostridium beijerinckii Donker 1926 (Clostridium beijerinckii Donker 1926을 이용한 혐기성 소화공정에서 체류시간 변화에 의한 수소 생산과 동력학적 특성)

  • Jeong, Tae-Young;Cha, Gi-Cheol;Choi, Suk Soon
    • Applied Chemistry for Engineering
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    • v.18 no.2
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    • pp.162-167
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    • 2007
  • Hydrogen production and its dynamics were investigated in the continuous anaerobic digestion process using Clostridium beijerinckii Donker 1926. In this work, glucose was used as a substrate and hydraulic retention times (HRT) were 0.5, 0.25 or 0.125 day. The removal efficiency of carbohydrate was over 99% under all of HRT conditions. As HRT was shorter, COD removal efficiency became lower while hydrogen content in the total gas and hydrogen production rate became higher. The cell growth yield and hydrogen production yield were 0.27 g-VSS/g-glucose and 0.26 L/g-glucose, respectively, at the steady state. It is expected that the microorganism is able to produce hydrogen when used in the wastewater treatment containing carbohydrate such as glucose. Also, the results in this study could be applied to the actual hydrogen gas production, a promising alternative energy.

Studies on the Phisical Environmental Factor Analysis for Water Quality Management in Man-made Lake of Korea (국내 인공댐호의 물리적 환경인자에 의한 호수특성 고찰에 관한 연구)

  • 김좌관;홍욱희
    • Journal of Environmental Science International
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    • v.1 no.2
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    • pp.49-57
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    • 1992
  • First, We classified man-made lakes in Korea as 4-type lakes, that is, there were River-run lakes, Dendritic lakes, Reservoir-lakes, River-mouth lakes, We studied on the environmental factors of 3-type lakes except River-mouth lakes, compared these lakes with natural lakes in foreign country. Environmental factors were watershed area, lake storage, mean depth, hydraulic retention time. As a results, 3-type lakes in Korea had remarkable differences one another according to above-mentioned environmental factors. First, We recognized that River-run lakes had higher nutrient loading according to having wider watershed area than natural lakes, and had lower algal growth rate according to shorter hydraulic retention time than natural lakes. Dendritic lake had higher nutrient loading than natural lakes, longer retention time than River-run lake. Reservoir-lakes had environmental factors between Dentritic lakes and River-run lakes. Therefore, If this studies had no quantitative results about various factors, We recognized that man-made lakes in korea had different environmental factors as compared with natural lakes, and had clear classification among 3-type lakes.

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Electric Power Generation and Treatment Efficiency of Organic Matter on Hydraulic Retention Time in Microbial Fuel Cell Reactor (미생물 연료전지 반응조의 수리학적 체류시간에 따른 유기물질 처리효율과 전력생산)

  • Choi, Chansoo;Lim, Bongsu;Xu, Lei;Song, Gyuho
    • Journal of Korean Society on Water Environment
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    • v.25 no.1
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    • pp.159-166
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    • 2009
  • This study has been attempted to generate electricity, while simultaneously treating artificial organic wastewater using both batch and continuous microbial fuel cells (MFCs). In the batch MFC, current-voltage curve showed an onset potential of -0.69 V vs. Ag/AgCl. The potential range between this potential and 0 potential displayed an available voltage for an automatic production of electric energy and glucose, which was oxidized and treated at the same time. The 486 mg/L glucose solution showed the maximum power of $30mW/m^2$ and the maximum current density of $75mA/m^2$ shown in the power curve. As a result, discharging of the cell containing COD 423 mg/L at the constant current density of $60mA/m^2$ showed a continuous electricity generation for about 22 hours that dropped rapidly due to dissipating of organic material. Total electric energy production was 18.0 Wh. While discharging, the pH change was low and dropped from pH 6.53 to 6.20 then increased to 6.47, then stabilized at this charge. The COD treatment efficiency was found to be 72%. In the continuous MFC, COD removal tends to increase as the hydraulic retention time is increased. At one day of hydraulic retention time as the maximum value reaches the COD removal efficiency, power production rate and power production rate per COD removal that were obtained were 68.8%, $14mW/m^2$, and $20.8mW/m^2/g$ CODrm, respectively. In the continuous MFC, the power production rate per COD removal increases as the hydraulic retention time is increased and decreases as the organic loading rate is increased. At the values lower than an organic loading rate of $1kgCOD/m^3/d$, the values higher than about $18.1mW/m^2/g$ CODrm could be obtained.

Back Analysis of Unsaturated Hydraulic Conductivities for Transient Water Release and Imbibitions Measurement (부정류 유출 및 흡입시험에 대한 불포화 투수계수의 역해석)

  • Oh, Seboong;Kim, Do-Hyung;Song, Young-Sug
    • Journal of the Korean Geotechnical Society
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    • v.34 no.3
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    • pp.5-12
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    • 2018
  • Tests for transient water release and imbibitions measurement were conducted to estimate the unsaturated hydraulic conductivities by using back analysis. By using transient hydraulic characteristics, both the soil water retention curve and hydraulic conductivity fuction can be evaluated effectively and accurately. In this study the experiment for three samples were conducted accurately to measure the change of water content with time for various steps of matric suction. The back analysis calculated the amount of transient flow reliably in comparison with the experimental results. In the soil water retention curve there was no significant difference between the result of back analysis and that of experiment. The hydraulic conductivity function from back analysis was compared with the theoretical relation based on retention curve but they showed much difference. However, the unsaturated hydraulic behavior obtained by the combination of experimental and analytical techniques are considered to agree with the actual behavior.

A Study on the Aerated Submerged Fixed-Film Bioreactor for Military Installation Wastewater Treatment (군용시설물(軍用施設物) 폐수처리(廢水處理)를 위한 고정생물막공법(固定生物膜工法)의 연구(硏究))

  • Suh, Hyung Suk;Ryu, Seong Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.7 no.1
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    • pp.37-45
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    • 1993
  • This research was performed to examined the applicability of a fixed-biofilm process for the wastewater treatment of military installations. Utilizing plastic net media, synthetic wastewater-average $BOD_5$ cocentration was $192mg/l$ treated in the three sets of reactors that have 8 hours, 6 hours, and 4 hours of hydraulic retention time. The results of this experiment showed that the biofilm was not detached easily, and the reactor was not closed by excess biomass. The average soluble $BOD_5$ concentrations of effluent were $6.0mg/l$ with 8 hours of retention time, $11.3mg/l$ with 6 hours of retention time, and $19.4mg/l$ with 4 hours of retention time. Especially it was reduced to $5.7mg/l$ in the second stage reactor with 4 hours of retention time. These resulted that the fixed-biofilm process could be adapted for the treatment of military installation wastewater.

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Effects of Retention Time on the Simultaneous of Odor Removal and Sludge Solubilization Using a Non-Thermal Plasma System (저온 플라즈마와 활성슬러지 복합 공정에서 체류시간 변화가 악취 저감 및 슬러지 가용화에 미치는 영향)

  • NamGung, Hyeong-Gyu;Hwang, Hyun-Jung;Song, Ji-Hyeon
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.6
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    • pp.815-824
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    • 2011
  • In this study, a non-thermal plasma system was employed to simultaneously remove odorous compounds and organic sludge. The system consisted of two reactors; the first one was the non-thermal plasma reactor where ozone was produced by the plasma reaction and the ozone oxidized hydrogen sulfide, the model odorous compound, and then the ozone-laden gas stream was introduced to the second reactor where wasted sludge was disintegrated and solubilized by ozone oxidation. In this study, the gas retention time (GRT) and the hydraulic retention time (HRT) were changed in the two-reactor system, and the effects of GRT and HRT on reduction efficiencies of odor and sludge were determined. As the GRT increased, the ozone concentration increased resulting in an increasing efficiency of hydrogen sulfide removal. However, the overall ozone loading rate to the second sludge reactor was the same at any GRT, which resulted in an insignificant change in sludge reduction rate. When HRTs in the sludge reactor were 1, 2, 4 hours, the sludge reduction rates were approximately 30% during the four-hour operation, while the rate increased to 70% at the HRT of 6 hours. Nevertheless, at HRTs greater than 4 hours, the solubilization efficiency was not proportionally increased with increasing specific input energy, indicating that an appropriate sludge retention time needs to be applied to achieve effective solubilization efficiencies at a minimal power consumption for the non-thermal plasma reaction.

Detention Orifice Design for Non-point Source Management Using SWMM (SWMM을 이용한 비점오염원 관리 저류지의 오리피스 설계기법 연구)

  • Cho, SeonJu;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.28 no.5
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    • pp.686-692
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    • 2012
  • This study illustrates how to design and evaluate a non-point sources management detention pond using SWMM. In particular, special attention is given to the orifice design. In SWMM, orifice properties that need to be defined include its height above the bottom of the storage unit, its type, its geometry and its hydraulic properties. Among the various characteristics of orifice, the orifice hole size which is closely related to hydraulic retention time is focused in this study. Sensitivity analysis of orifice size in annual non-point sources reduction efficiency is carried out. In addition, a methodology which can be used to design a virtual junction in SWMM has been proposed to quantify water quality improvement triggered by the detention pond installation. As a result, it is recommended that a detention outlet should be designed to be about 2 to 3 days of hydraulic retention time.

A Study on Change of Soil-Water Retention Curve with Different Net Confining Pressures and Porosities using a Suction-Saturation Control Technique (흡입력-포화도 조절 기법을 이용한 불포화토의 함수특성곡선에 미치는 간극비 및 순구속압력의 영향 연구)

  • Lee, Joon-Yong;Yu, Chan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.4
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    • pp.93-103
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    • 2012
  • A suction-saturation control technique based on flow pump system was developed to investigate hydraulic properties in unsaturated soils. The flow pump system is designed based on the principle of the axis-translation technique and triaxial equipment, and gives the suction-time and suction-saturation curves, the primary relationship needed for interpreting the response of unsaturated soils and link between theory and the material properties in unsaturated soil mechanics. Using the suction-saturation control technique, suction-time relationship and soil-water retention curve (SWRC) during hydraulic hysteresis were investigated with different net confining pressures and porosities. Three types of soils-two sands and a silt were used in this paper. This paper showed the effect of the hysteresis on the SWRC due to different net confining pressures and porosities. This means that a careful decision must be made as to which condition is to be modeled, since the delicate difference of the conditions in physical modeling can cause the different experimental output.

Biological Removal Phosphorus Containing Swine Wastewater (생물학적 처리에 의한 돈사폐수의 인제거)

  • 신남철;박정호
    • Journal of Environmental Health Sciences
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    • v.26 no.4
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    • pp.15-20
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    • 2000
  • The studies of swine wastewater treatment aim to development of process using soil microorganism. Removal rate of swine wastewater containing organic matter was 99 percent in case of high loading rate. Microorganism was devoted to improve the treatment efficiency of the process. According to the result obtained from biological treatment of high loading rate swine wastewater. Hydraulic retention time was 2.3 days in unit process of biological phosphorus removal. BO $D_{rm}$ / $P_{rm}$ ratio was 1122 in room temperature anaerobic process and 355.6 in mesophilic anaerobic process. And then phosphorus removal rate mesophilic anaerobic process was 3 time as much as than room temperature acaerobic process.

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Effects of Different Hydraulic Retention Times on Contaminant Removal Efficiency Using Aerobic Granular Sludge (HRT 변경에 따른 호기성 그래뉼 슬러지의 오염원 제거효율에 미치는 영향)

  • Kim, Hyun-Gu;Ahn, Dae-Hee
    • Journal of Environmental Science International
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    • v.28 no.8
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    • pp.669-676
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    • 2019
  • The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.