• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.140-147
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• 2010

In existing design method for aeration tank water temperature was considered as governing variable for applying safety factor. This study tried a few new approach of aeration tank design using SOUR at various temperature conditions. Specific substrate utilization rate (U) and specific oxygen uptake rate (SOUR) both were analyzed at various temperature and SRT. The laboratory scale reactor was operated on various temperature ($10^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$) and SRT (5day, 10day, 20day, 30day). In this study, SOUR tended to increase with the temperature increased. On the other hand, SOUR tended to decrease when SRT increased from 5 days to 30 days. Empirical equations were obtained SOUR=a/SRT+b and $SOUR=(a/m){\cdot}U+(b-a(n/m))$ from the relationship between SRT, U and SOUR. Empirical equations shows the possibility as a new design method for the aeration basin.

• Journal of Welding and Joining
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• v.32 no.5
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• pp.13-20
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• 2014

A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.468-473
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• 2010

The purpose of this study is to derive the correlation between the Specific Phosphorus Release Rate (SPRR), Specific Phosphorus Uptake Rate (SPUR) and Specific Oxygen Uptake Rate (SOUR) at various Sludge Retention Time (SRT) condition in the A/O process. The laboratory scale reactor was operated on various SRT (10 day, 20 day, 30 day, 40 day). In this study, the SPRR, SPUR and SOUR tended to decrease with the SRT increase. Empirical equations was be obtained $y=4.54E-006x^2+0.0007x-0.0315$, $R^2=0.925$ (SOUR vs. SPRR) and $y=3.22E-006x^2+0.0004x-0.0173$, $R^2=0.928$ (SOUR vs. SPUR) from the relationship between SRT, SPRR and SPUR and SOUR. Therefore, the anaerobic tank design based on the research result such as SPRR, SPUR of a phosphorus design and SOUR would be possible.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.288-295
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• 2008

The increase use of natural gas as an energy source has been continuous demand for ever-increasing strength in gas transmission pipeline materials in order to achieve safe and economic transportation of natural gas. In particular, linepipe material for sour gas service primarily needs to have crack resistant property. However, applications of sour linepipes are expanding toward deep water or cold region, which require higher toughness and/or heavier wall thickness as well as higher strength. To improve the crack resistance of linepipe steel in sour environment, low alloy steel are produced by controlled rolling subsequently followed by the accelerated cooling process. This paper summarizes the design concepts for controlling crack resistant property low alloy linepipe steels for sour gas service.

• Corrosion Science and Technology
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• v.17 no.5
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• pp.249-256
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• 2018

Metallic structures in the oil and gas production undergo severe degradation due to sweet and sour corrosion caused by the presence of $CO_2$ and $H_2S$ in the fluid environment. The corrosion behavior of 304 austenitic stainless was investigated in the presence of varying concentrations of $CO_2$ or $H_2S$ and $CO_2+H_2S$ to understand the effect of the parameters either individually or in combination. Potentiodynamic polarization study revealed that a small amount of $CO_2$ aided in the formation of calcareous deposit of protective layer on passive film of 304 steel, while increase in $CO_2$ concentration ruptured the layer resulting in sweet corrosion. The presence of $S^{2-}$ damaged the passive and protective layer of the steel and higher levels increased the degradation rate. Electrochemical impedance studies revealed lower polarization resistance and impedance at higher concentration of $CO_2$ or $H_2S$, supporting the outcomes of polarization study. XRD analysis revealed different types of iron carbides and iron sulphides corresponding to sweet and sour corrosion as the corrosion products, respectively. SEM analysis revealed the presence of uniform, localized and sulphide cracking in sour corrosion and general corrosion with protective carbide layer amid for sweet corrosion.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.717-722
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• 2012

Fluoride can be easily found in semiconductor and display industry. However, there is a lack of research for its effects on the related wastewater treatment. The objective of this study is to evaluate the microbial inhibitory effect by fluoride injection. The research entailed the assessment of removal efficiency of $TCOD_{Cr}$ according to the fluoride concentration and also the Specific Oxygen Uptake Rate (SOUR) was measured. The laboratory scale reactor was prepared and operated with the fluoride concentrations of 0, 10, 50, 100, and 200 mg/L based on concentrations frequently occurring in the wastewater. The results from this study showed that, as the fluoride concentration increase, the Specific Substrate Utilization Rate (SSUR) tend to decrease as expected. Also, the increase in fluoride concentrations resulted in the decrease in SOUR. It is determined that fluoride injection affects the microbial activity. Especially, The addition of above 200 mg/L fluoride into reactor caused rapidly decreased SSUR and SOUR due to the inhibitory effects of fluoride.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.188-193
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• 2011

The effects of coagulants on the microorganisms when they are injected directly into the biological treatment facility for T-P removal have been easily observed from the results of past experiments. As such this study is set out to derive the effective plans for the coagulant dosage by analyzing the effects of the injected coagulant on the microbial activity during the chemical treatment for T-P removal. The research methods entailed the assessment of removal efficiency of T-P according to the coagulant dosage while changing the molar ration between Alum and influent phosphorus. At the same time Specific Oxygen Uptake Rate (SOUR) according to the coagulant dosage was measured. SOUR was used as a method for indirect assessment of the microbial activity according to the coagulant dosage. The results from the study showed that with the increase in the alum dosage, the removal efficiency T-P tended to increase. On the other hand, the increase in coagulant dosage resulted in the decrease in SOUR, which indicates the decrease in the microbial activity. Such reduction in the activity could be explained by the increase in the concentration of removal efficiency of $TBOD_5$. Based on experiment results from the study, it is determined that coagulant dosage affects the microbial activity. Moreover, the indirect assessment on the microbial activity using SOUR is considered possible.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.711-718
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• 2013

This study examined the effect of 3 evaluation factors(extraction temperature, extraction time and drinking temperature) on the 5 tastes (sour, sweet, malty, salty and bitter) of coffee. the aim of this experiment were threefold: i) to investigate the change of the 5 tastes depending on the each 3 evaluation factor ii) to examine the change of the 5 tastes depending on the extraction time, drinking temperature under fixing the group of extraction temperature iii) to research the preference for the taste of coffee depending on 3 evaluation factors. As a result, in relation to the evaluation factors, significance difference was made at the sour taste. And when extraction temperature was higher and extraction time was longer, the sour taste was felt stronger. To the contrary, when drinking temperature was lower, sour was stronger. When the extraction Temperature group was controlled, the sour and malty taste were stronger. The sour taste was stronger when drinking temperature was lower and delicate flavor was stronger when drinking temperature was higher. High preference was demonstrated at extraction temperature($98^{\circ}C$), extraction time(0 minute), drinking temperature($60^{\circ}C$) and higher malty taste.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.39-42
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• 2013

자동차 및 에너지 산업의 적용을 목표로 고망간강의 기계적 성질 향상 연구가 활발히 진행된 반면 내식성 연구는 미비하다. 본 연구에서는 염수 환경 및 H2S 환경에서 4종의 고망간강의 내식성에 미치는 크롬 및 망간의 영향을 조사하였다. 비교재로 사용된 탄소강 대비 실험재의 부식 속도는 침지 실험을 통해 얻어졌다. 또한 내식성 기구 고찰을 위하여 상평형 프로그램을 통하여 녹 층을 예측하고, 침지실험으로부터 얻어진 녹 층을 XRD, SEM-EDS 및 TEM-EDS로 분석하였다. 3.5% NaCl 용액에서 크롬 및 망간이 모두 내식성을 향상시킨 반면, synthetic seawater에서는 크롬만이 내식성을 향상시켰다. 또한 이들 염수 환경과 달리 H2S 환경에서 크롬과 망간 모두 내식성을 향상시키지 못했다. 환경에 따라 강의 내식성에 미치는 합금 원소의 영향이 상이한 원인은 각각의 환경에서 형성된 녹층의 구성 물질의 차이에 의한 것으로 이에 대하여는 본문의 된 녹 층 분석 결과에서 자세히 설명되었다.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.566-571
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• 2006

A sequencing batch biofilm reactor (SBBR) operated with a cycle of anaerobic - aerobic - anoxic - aerobic has been evaluated for the nutrient removal characteristics. The sponge-like moving media was filled to about 10% of reactor volume. The sewage was the major substrate while external synthetic carbon substrate was added to the anoxic stage to enhance the nitrogen removal. The operational results indicated that maximum T-N and T-P removal efficiencies were 97% and 94%, respectively were achieved, while COD removal of 92%. The observations of significant nitrogen removal in the first aerobic stage indicated that nitrogen removal behaviour in this SBBR was different to conventional SBR. Although the reasons for aerobic nitrogen removal has speculated to either simultaneous nitrification and denitrification or anoxic denitrification inside of the media, further researches are required to confirm the observation. The specific oxygen uptake rate (SOUR) test with biofilm and suspended growth sludge indicated that biofilm in SBBR played a major role to remove substrates.