• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.299-305
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• 1993

Numerical identification was carried out for an isolate of Streptomyces D2-5 producing a new restriction endonuclease Svi I. Fifty taxonomic unit characters were tested and the data were analyzed numerically using the TAXON program. The isolate was best matched to Streptomyces violochromogenes in the major cluster 18 of Streptomyces. Therefore, it was concluded that the isolate was identified to be a member of Streptomyces violochromogenes.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.42-47
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• 2006

The biological nutrient treatment is formed with repetition and rearrangement of anaerobic, anoxic and oxic tank. In this case, VFAs is generated in the anaerobic tank and the anoxic tank. The VFAs is an important factor for removal of nitrogen and phosphate and SVI. So, in this study I investigated to find a relationship among the generation rate of the VFAs according to the change of F/M ratio and the characteristic which can eliminate organic matter and nitrogen according to the change of residual concentration of the VFAs and the efficiency of the process and also SVI in wastewater treatment. $A^2/O$ process was used for wastewater treatment. F/M ratio was under the control of the change of MLSS concentration. When the F/M ratio was changed from 0.16 to 0.08 kg-BOD/kg-MLSS/day, the VFAs's production volume increased based on the reduction of F/M ratio in batch reaction. And the residual concentration of the VFAs decreased at first and then increased later. SVI and SS were high when F/M ratio was $0.16kg/kg{\cdot}d$ and showed stable status when F/M ratio decreased $0.11{\sim}0.13kg/kg{\cdot}d$. However, SVI and SS continuously increased with decrease of F/M ratio and were high at $0.08kg/kg{\cdot}d$. In the result of comparison between residual concentration of the VFAs and denitrification rate in anoxic tank, the less residual volume of the VFAs was in anoxic tank, the higher denitrification ratio became. The optimal residual-concentration of the VFAs considering SVI and removal efficiency of nitrogenwas $1.4{\sim}2.2mg/L$. At that time F/M ratio was $0.11{\sim}0.13$ kg-BOD/kg-MLSS/day.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1101-1106
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• 2006

Many BNR (Biological Nutrient Removal) plants have experienced a bulking problem, mainly due to the growth of filamentous organisms, particularly during the winter months. This study investigated the problem of bulking due to the growth of M. parvicella both at a full-scale municipal wastewater treatment plant and a pilot scale plant located in the C city. The full-scale facility was operated at a flow rate of $51,000m^3/d$, an F/M (Food-to-Microorganism) ratio of 0.12 kgBOD/kgMLVSS/d and an SRT (Solids Retention Time) higher than 25 days, respectively. This plant experienced bulking and foaming problems at low temperatures below $15^{\circ}C$ since it was retrofitted with the BNR system in 2003. The pilot plant employed had an identical process configuration as the full scale one and used the same wastewater source. It was operated at a flow rate of $3.8m^3/d$, temperatures between 10 to $25^{\circ}C$ and SRTs between 10 and 25 days. At full scale, the M. parvicella growth and SVI (Sludge Volume Index) patterns were studied in conjunction with temperature variations. At pilot scale, DO and SRT variations were also explored, in addition to the filamentous bacteria growth and SVI patterns. During the full-scale investigation, over a 3 year period, it was noted that the SVI was maintained within acceptable operational values (i.e. under 160) during the summer months. Moreover settling in the secondary clarifiers was good and was not affected by the presence of M. parvicella. In contrast, at low mean temperatures during winter, the SVI increased to over 300. Overall, as the temperature decreased, the predominance of M. parvicella became apparent. According to this study, M. parvicella growth could be controlled and SVI could drop under 160 by a change in operational conditions which involved an increase in DO concentration between 2 and 4 mg/L and a decrease in SRT to less than 20 days.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.561-570
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• 2013

There are two types of rectangular secondary clarifier at biological nutrient removal (BNR) facility to settle MLSS; conventional activated sludge secondary clarifier and Gould Type I clarifier. In this study, the performances of two types at respective biological nutrient removal facility are compared using weekly operational data. Surface Overflow Rate (SOR), Surface Loading Rate (SLR), Sludge Volume Index (SVI), secondary effluent SS concentration are studied. It has found that Gould Type I has 3.5 times less average secondary effluent SS concentration that is 2.4 mg/L than that of conventional activated sludge secondary clarifier. Both SOR and SLR have shown little effect on secondary effluent SS concentrations at Gould Type I clarifier in contrary that SOR affects the secondary effluent SS concentrations at conventional activated sludge rectangular secondary clarifier. From this study, it is recommended that Gould Type I must be considered for secondary clarifier when BNR plant is designed.

• Textile Coloration and Finishing
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• v.8 no.5
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• pp.84-89
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• 1996

This study carried out batch and continuous experiments using calcium hydroxide as neutralization agent and immobilization media for removing the ethylene glycol in the pretreated polyester weight loss wastewater. The $TCOD_{Mn}$ concentration in the treated wastewater using culture of iramobilization and suspension for the synthetic wastewater were found as 650mg/l and 1,250mg/l after 48hours, respectively. SVI(Sludge Volume Index) and $TCOD_{Mn}$ concentration were 74 and 73mg/l at optimum F/M ratio, 1.32kg-TCO $D_{Mn}$ /day. kg-MLVSS. The $TCOD_{Mn}$ concentration and removal efficiency were 213mg/l and 93.5% by continuous experiments in the air-lift bioreactor, respectively. The $TCOD_{Mn}$ concentration was 82mg/l, and also the MLVSS concentration was 2,550mg/l, when the volumetric loading rate was 3.04kg-$TCOD_{Mn}/m^{2}$ day for real polyester weight loss wastewater.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.274-277
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• 2001

This research was conducted as a part of continuous development of a bioprocess to treat thiocyanate($SCN^-$) in the leachate from an industrial landfill site. Detailed characteristics of the leachate, physical and chemical, was analyzed in this study. Time to reach equilibrium in $SCN^-$ degradation at different temperature, similar to the annual variation. was investigated for posssible adaptation of the bioprocess in the treatment site. Complete mineralization of $SCN^-$ to ammonia. bicarbonate and sulfate at all temperature range with except $5^{\circ}C$ trial was observed with different time elapsed to reach equilibrium. which shortened as the process of Fill-Draw proceeded. The final metabolites were mainly nitrate and sulfate. No fouling odor was detected and the settling characteristic of the biomass after the treatment was good(i.e., sludge volume index(SVI) ${\le}$80). Using MWT sludge as an inoculum showed better performance with respect to the elapsed time for treatment and sedimentation characteristics than those of using 2BET sludge.

• The Korean Journal of Nuclear Medicine
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• v.19 no.2
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• pp.43-50
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• 1985

With the improvement of hemodialysis, the course of the disease in patient with endstage renal disease has been clearly improved. Nevertheless, among several shortcomings to our present mode of renal replacement therapy, cardiovascular complications have been the leading cause of morbidity and mortality. Several factors such as anemia, arteriovenous shunting of blood, intermittent extracorporeal circulation and hypertension may be contributing. But little is known about the quantitative cardiac hemodynamic characteristics occurred during hemodialysis. The purpose of this study is to observe the sequential hemodynamic changes before, during and after the hemodialysis and to investigate reliable parameters in the detection of ventricular dysfunction. In the present study, equilibrium radionuclide cardiac angiography was performed and left and right ventricular volume indices, ejection phase indices of both ventricular, performance were measured in the 16 stable patients with chronic renal failure treated with maintenance hemodialysis sequentially i.e. before, during (early and late phase) and after the hemodialysis. The results obtained were as follows; 1) The indices of the left ventricular function were not changed during the hemodialysis but increased after the hemodialysis. 2) The indices of the right ventricular function(EF, SVI) were significantly decreased in the early phase (15, 30 minutes after starting extracorporeal circulation) but recovered after the hemodialysis. 3) The ratio of right ventricular to left ventricular ejection fraction was significantly decreased in the early phase and the lung volume indices were significantly increased at the same phase. As a conclusion, hemodialysis improves left ventricular function maybe due to increased contractility, and effects on the right ventricular function maybe due to the increased lung volume in the early phase of hemodialysis.