• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.385-389
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• 2006

다중주파수 초음파를 이용한 하수슬러지의 전처리시 탈수성와 침강성에 관한 실험을 실시하여 다음과 같은 결론을 얻었다. 1. CST 변화량은 조사시간 80분까지 증가하다가 이후에는 감소하는 경향을 보여 탈수성이 개선될 수 있음을 보였다. 또한 삼중주파수가 이중주파수 일때보다 더 큰 영향을 끼쳤다. 2. $SV_{30}$의 변화량은 초음파 조사와 동시에 급격히 변화하여 침강성의 악화를 가져왔다. 또한 삼중주파수가 이중주파수 일때보다 침강속도를 더 빨리 악화시켰다. 3. 수온은 상승하였고, pH의 변화는 거의 일어나지 않았다. 본 실험에서 다중주파수를 사용하였을때, 단일주파수를 사용했을때보다 효율이 높았다. 그러나 다중주파수를 이용한 초음파 처리시 정확한 탈수성과 침강성 평가를 위해 ECP, 여과비저항(SRF), 입도분도, 점도 등 다양한 후속연구를 진행해야 할 것이다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.362-364
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• 2006

Starvation 동안 슬러지를 폭기시킨 경우 floc의 크기감소가 더 크게 일어났다. SBR의 재운전으로 회복된 floc의 크기는 슬러지를 폭기시키지 않은 경우 starvation 이전과 비교하여 더 커졌으며, 슬라지를 폭기시킨 경우 starvation 이전보다 작아졌다. Starvation 동안 슬러지를 폭기하지 않은 경우 fractal dimension은 큰 폭으로 감소하지만, 폭기하였을 때는 감소폭이 매우 작았다. 이후 SBR의 재운전으로 인한 fractal dimension은 증가하였다. 슬러지의 침강성은 starvation 동안 폭기한 경우 폭기하지 않은 경우보다 SBR 재운전 직후 슬러지의 침강성이 더 불량하였으며, starvation 동안 폭기하지 않았을 때 슬러지 침강성의 회복현상이 나타났지만, 폭기를 수행한 경우 침강성의 회복이 느리게 일어났다. Starvation 동안 슬러지의 폭기 및 비폭기 수행결과 침강성은 fractal dimension보다 floc의 크기에 더 크게 좌우되는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.722-726
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• 2012

각 해역의 부유 플록은 그 해역의 조건에 따라 각기 다르게 형성된 플록이므로, 부유 플록 자체의 특성(결합강도, 밀도 및 크기 등)은 현장특성에 따라 현저하게 다른 "site-specific"한 특성을 가질 뿐만 아니라, 동일 해역이라 하더라도, 조류 등에 의한 유속변화에 따른 흐름전단응력의 증감에 따라 플록의 특성 또한 시간적으로 크게 변화할 수 있다. 이에 현장의 플록 특성이 반영된 부유플록의 침강속도를 산정하기 위해 입도 측정원리중 하나인 BW방법을 응용한 전북대 Owentube를 자체 제작하여 연구가 수행되었으며, 본 연구를 통하여 도출된 현장에서의 점착성 부유 플록의 침강속도 산정 결과는 향후 퇴적물 이송 및 수질 예측을 위한 수치모형 적용시에 필수적으로 요구되는 침강 및 퇴적특성 입력자료로 유용하게 사용될 수 있을 것이다.

• Current Research on Agriculture and Life Sciences
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• v.8
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• pp.115-118
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• 1990

The packed cell volume(PCV) of chicken, volume percentage of erythrocytes in whole blood, was reshuffled of 20%, 40% and 60% using autoplasma, and the red blood cell sedimentation rate was measured in Westergren tubes at room temperature($27{\pm}1^{\circ}C$) and low temperature ($8{\pm}1^{\circ}C$). The results obtained were summarized as follows. 1. The sedimentation rates of chicken red blood cell were settled faster at low PCV than higher PCV, i,e., there was a reverse relationship between the sedimentation rate and PCV. 2. The sedimentation rate of chicken red blood cell was accelerated more at high temperature than low temperature. 3. The sedimentation rate of reshuffled chicken red blood cell by time was almost linear for several hours.

• Journal of the Korean Geotechnical Society
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• v.23 no.8
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• pp.129-135
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• 2007

In order to analyze the effect of fines content on sedimentation and self-weight consolidation characteristics of dredged soil, a series of self-weight consolidation tests with different fines content were conducted. From the experimental test results on dredged soils, it was found that the coefficient of sedimentation and consolidation is correlated with water content. And it is related to fines content as well. So, in this study, correlation between fines content and the coefficient of sedimentation and consolidation has been proposed. And it is expected that the coefficient of sedimentation and consolidation can be estimated by the percentage of fines content.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.1
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• pp.151-159
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• 2006

In these days, the importance of sludge treatment is emerging due to the London Convention, so this study was conducted to propose the alternatives for the improved sludge treatment on the organic wastewater and sewage sludge with JAR test and settling column equipped with stirrer. The minimum coagulant dosage to earn the optimum sludge settling efficiency resulted from 200mg/l and each critical sludge settling interface showed no distinct difference when PAC was dosed over 200mg/l. Accordingly, Clarification Rate(CR) with 200mg/l dosage was calculated to CR=(Ho-Ht) / Ho=1-0.4=0.6 because the critical sludge settling height stopped at 0.4. The settling velocity of sludge interface was decreased with the increase of MLSS concentration but rather increased with MLSS concentration over 1,000mg/l. This resulted from positive effect of interacted coagulation for floc formation by transfer to the zone of compressed settling when MLSS concentration increased over 1,000mg/l. The settling velocity of sludge interface showed $28.66{\times}10^{-3}/min$ for average settling velocity of sewage sludge which is 6.7 times higher than $4.25{\times}10^{-3}/min$ for average settling velocity of organic wastewater sludge. The increasing rate of CR for organic wastewater activated sludge was higher than that of settling velocity under 200mg/l of PAC dosage but settling velocity was higher than CR over 200mg/l of PAC dosage. However, in case of sewage sludge, the differential rate of CR was low when PAC dosage was increased but the settling velocity was suddenly increased with over 200mg/l dosage. Therefore coagulation effect was more efficient to MLSS settling velocity rather than SS removal effect in the supernatant.

• Parasites, Hosts and Diseases
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• v.30 no.3
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• pp.209-218
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• 1992

When cystic fluid of Taenia solium metacestodes (CF) was filtrated through Sephacryl S-300 Superfine, major proteins were in fractions III add IV Major protein in fraction III was Band C protein of 150 kDa and that in fraction IV was Band N protein (Choi et of., 1990). When CF was electrophoresed in 0.9% agarose gel and reacted with anti-CF rabbit serum (RACF), two main bands, a long outer and a short inner band, were precipitated, together with 8 minor bands. RACF reacted with fraction III forming the long outer band whereas RACF formed the short infer band with fraction IV in immunoelectrophoresis (IEP) The long outer precipitin band of CF fraction III was similar to antigen B in hydatid fluid (HF) of Oriol et at. (1971), while the short inner band of CF fraction IV was similar to HF antigen 5 of Caption et at. (1967) . When HF was reacted with RACF, the short inner band was immunoprecipitated without forming the long outer band. Common antigenicity between CF and HF seemed to exist in fraction IV rather than in fraction III of CF. Patient sera of neurocysticercosis reacted more frequently with fraction III than with fraction IV.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.4
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• pp.123-129
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• 1993

Because the existing scour prediction formulas for plunge pools of pipe culverts and spillways give a wide range of predicted scour depths, it is difficult to estimate actual scour depths. A review of literature showed that wide range of predicted values was caused mostly by lack of thorough analysis of the scour mechanism. In this study, the effects of the parameters govering scour were examined, and the scour potentials were measured. The major variables govering scour were the velocity and size of jet impinging into the plunge pool, the submerged weight of bed material, the ratio of jet size to bed material size, the tail watr depth of the plunge pool, and the angle of jet impact on water surface. The ratio of jet size to bed material size to bed material size was found to be another significant parameter affecting scour for larger bed materials. A densimetric Froude nember of the bed material in incipient motion was formulated. This number represented the scour potential of the jet at the point where the bed material was tested.

• Journal of the Korean GEO-environmental Society
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• v.25 no.10
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• pp.11-18
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• 2024

For fine grained soils of 10 samples around coast areas in Korea, classified into three regions of West Coast, Kyungnam and Jeonnam, settling-consolidation tests of 161 were performed to evaluate characteristics of sedimentation and consolidation during dredging and reclamation and characteristic values proposed from Yano's method (1985) were used to analyze and assess their characteristics in this research. The settling-consolidation tests with columns of 1m in height were performed, changing initial water content and initial height of slurry, for 4, 3, and 3 samples from regions of West Coast, Kyungnam, and Jeonnam respectively. From test results effect of initial water content on coefficient of consolidation-sedimentation and initial velocity of sedimentation were analyzed, and regression equations having correlation between them were derived. The void ratios at initiating consolidation were analyzed on each samples and suggested regression equations for three regions. In addition, as a result of analyzing relation between initial void ratio of slurry and void ratio at initiating selfweight consolidation, expected ranges of void ratio at initiating consolidation for fine-grained soils from three regions of Korea coast could be proposed.

• Resources Recycling
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• v.2 no.2
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• pp.16-21
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• 1993

This study was carried out to investigate the settling characteristics of Fe(II) and Fe(III) hydroxide precipitates formed by pH adjustment of aqueous solution to remove ferrous and ferric ion in waste water. The results obstained in this study are as fellows : The settling rate was effectively increased with increasing the pH values of aqueous solution regulated by CaO and with increasing the amount of flocculant, on the other hand, application of excess flocculants decreased the settling rate. It is desirable that the concentration of iron ion is kept under $10^{-2}$ mol/ㅣ because the settling rate was decreased with increasing the concentration of iron hydroxide precipitates.