• 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.

• 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 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.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.

• 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.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.226-230
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• 2007

In order to achieve high-level expression of interferon-${\alpha}1$ (IFN-${\alpha}1$) during fed-batch fermentation of recombinant E. coli, effects of oxygen supply and induction temperature on the expression of recombinant proteins were evaluated. Supplementation of oxygen and its transfer into cells is one of the most important parameters involved in the design and operation of mixing-sparging equipment for bioreactors. Generally, higher oxygen supply stimulates cell growth of aerobic microorganism and consequently the amount of products is increased. In this study, the optimum aeration strategy for the higher production of IFN-${\alpha}1$ during fed-batch fermentation of recombinant E. coli was surveyed. The growth of the cells was also monitored with four different concentrations of dissolved oxygen (DO; limiting, 20%, 35%, 50%) conditions. The DO was controlled by varying aeration rates of air and pure oxygen. Oxygen uptake rate (OUR) and specific oxygen uptake rate (SOUR) were evaluated and compared for the enhanced growth and induction of the cells and IFN-${\alpha}1$, respectively. We confirmed that increased DO by additional oxygen supply, up to 35%, can improve the production of IFN-${\alpha}1$ during the fermentation.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.677-686
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• 2006

This study was the effectiveness of two downflow BAF(Biological Aerated Filter) systems at conventional water treatment system. A BAF reactor placed in front of coagulation and sedimentation tanks(Mode A) and after coagulation and sedimentation tanks(Mode B) that were compared in terms of removal of suspended particles, organic matters, and ammonia nitrogen. The suspended particles removal efficiency was over 80% for both Mode A and B, although Mode A gave slightly better results. $BOD_5$ removal and nitrification efficiencies were more than 90% for both reactor. The organic matter and ammonia removals were also superior in the Mode A. The biofilm thickness and biomass increased as increment of EBCT and the upper part of reactor more about 30% than lower part. The specific oxygen uptake rate(SOUR) was higher the upper part of reactor and Mode A than the lower part of reactor and Mode B. A cost analysis showed that the Mode A system was more cost effectiveness. It could save the coagulant dose by about 67% and the chlorine demand by about 95%. The ideal place to put the BAF reactor was in front of the coagulation/sedimentation process.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.2
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• pp.79-86
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• 2016

The purpose of this study is to efficiently improve biological sequencing batch reactor (SBR) system of high-concentrated nitrate nitrogen in reverse osmosis (RO) concentrates by total dissolved solids (TDS) regulation. Since a laboratory-scale SBR system had been operated, we had analyzed specific denitrification rate (SDNR) and specific oxygen uptake rate (SOUR) for microbial activity in according to various injection concentration of TDS. As a result, higher injection concentration of TDS decreased SDNR, and delayed denitrification within denitrification process. Moreover, the higher injection concentration of TDS was, the lower microbial activity was during operation of laboratory-scale SBR system. Therefore, the regulation of TDS injection concentration is necessary to improve efficiency of nitrate nitrogen in the biological SBR system, and treatment of calcium ion ($Ca^{2+}$) is also specifically focused to remove nitrate nitrogen. Moreover, analytical data of SDNR and SOUR can be the effective kinetic design parameters to application of biological treatment of RO concentrate by aerobic granular sludge (AGS).