• The Korean Journal of Food And Nutrition
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• v.13 no.5
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• pp.477-482
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• 2000

For the purpose of explaining the dewatering phenomena of potato slice soaked in concentrated solution three models were proposed. Earlier model cannot explain the dewatering phenomena of potato slice in concentrated solution because of limiting its condition which is necessary to build a model. Therefore other three models were suggested and a model based on Fick\`s second law of mass transport at infinite plate conditions and numerical analysis was test model for explaining dewatering phenomena of potato soaked in concentrated solution. Apparent diffusion coefficient of water could be readily estimated from model III, and it could explain adequately the difference of the dewatering phenomena of various soaking conditions.

• The Korean Journal of Food And Nutrition
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• v.10 no.4
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• pp.462-467
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• 1997

The DIS process(dewatering and impregnation soaking process) are using for dewatering of food materials at room temperature. And the DIS process are resulted in diffusion process as well as dewatering phenomena. During the DIS process, plasmolysis or cytorrhysis was happened by according to solute size. A tissue state of food material was very important variables for movement of water or solute, and running conditions are important for dewatering and impregnation. And models for DIS process were fundamentally given by Fick's law at unsteady state or mass balance. For example, Bicompartmental Model was given for quantification of water loss and solid gain.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.2
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• pp.84-96
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• 1995

The dewatering characteristics of the sewage sludge was investigated through the experimental observations and model simulations. The activated sludge and the anaerobically digested sludge were examined for the dewaterability evaluation within the pressure range of $0{\sim}10^6N/m^2$. Modified Buchner funnel test and compression test by the consolidometer were conducted to evaluate average specific resistance, porosity, and moisture percentage of filter cake. Shirato's technique of compression-permeability test was followed for the pressure range lower than about $10^2N/m^2$. The flocculation effects on sludge dewatering was also examined for ferric chloride and polymeric flocculant. The application of hydrated lime which can be used for flue-gas desulfurization showed improved moisture percentage, and was thought to have positive feasibility in combined system of sludge dewatering and incineration. Determined characteristic constants were applied to Tiller's cake filtration model to simulate liquid pressure distribution and porosity distribution in cake. Model simulations showed a sharp drop of the porosity close to the cake-medium interface for the highly compressible material such as the activated sludge and the anaerobically digested sludge.

• Journal of Microbiology and Biotechnology
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• v.8 no.2
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• pp.165-170
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• 1998

Lipase-catalyzed esterification of n-butyl oleate was carried out in n-hexane as a model reaction. The optimal activity of Candida rugosa lipase was shown in a water activity ($a_w$) range of 0.52 to 0.65 at $30^{\circ}C$. The water produced from the esterification was removed by a tubular type pervaporation system. The rate of ester formed from the enzymatic esterification was allowed to be the same as the rate of water removal by maintaining an optimal $a_w$ of the reaction system using an on-off dewatering control device. The reaction rate and yield with a$a_w$ control were increased two folds higher than the respective values for the uncontrolled reaction.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.1
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• pp.1-6
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• 2015

The purpose of this study is to suggest the effective operation method by developing prediction model for the gas production rate, an indicator of the effectiveness of anaerobic digestion tank, using data mining. At the result, gas production estimate model is developed by using ANN within 10% error. It is expected to help operation of anaerobic digestion by suggesting selected parameter. Meanwhile case based reasoning is applied to develop dewatering cake management technology. Case based reasoning uses the most similar examples of past when a new problem occurs, therefore in this study, management measures are developed that proposes dewatering cake minimization with the minimum change by applying the case based reasoning to sludge disposal process.

• Geomechanics and Engineering
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• v.14 no.5
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• pp.467-477
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• 2018

Estimation of hydraulic parameters is a critical step during design of foundation dewatering works. When many piles are installed in an aquifer, estimation of the hydraulic conductivity should consider the blocking of groundwater seepage by the piles. Based on field observations during a dewatering project in Shanghai, hydraulic conductivities are back-calculated using a numerical model considering the actual position of each pile. However, it is difficult to apply the aforementioned model directly in field due to requirement to input each pile geometry into the model. To develop a simple numerical model and find the optimal hydraulic conductivity, three scenarios are examined, in which the soil mass containing the piles is considered to be a uniform porous media. In these three scenarios, different sub-regions with different hydraulic conductivities, based on either automatic inverted calculation, or on effective medium theory (EMT), are established. The results indicate that the error, in the case which determines the hydraulic conductivity based on EMT, is less than that determined in the automatic inversion case. With the application of EMT, only the hydraulic conductivity of the soil outside the pit should be inverted. The soil inside the pit with its piles is divided into sub-regions with different hydraulic conductivities, and the hydraulic conductivity is calculated according to the volume ratio of the piles. Thus, the use of EMT in numerical modelling makes it easier to consider the effect of piles installed in an aquifer.

• The Korean Journal of Food And Nutrition
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• v.12 no.6
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• pp.582-587
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• 1999

감자절편을 고농도용액에 침지하여 탈수시킨 결과 침지용액을 구성하는 용질의 분자량에 따라 탈수형태가 다르게 나타났다. 저분자 용액인 NaCl, PEG 400 용액에 침지한 경우 조직의 뒤틀림현상(cytorrhysis) 은 나타나지 않고 부피의 감소와 수분의 탈수현상이 나타난 반면 고분자 용액인 PEG 4000, PEG 6000용액에 침지한 경우 cytorrhysis 현상을 동반한 부피의 감소와 탈수현상이 나타났다. 초기 탈수속도는 저분자 용액에 침지시 더 빨랐으나 최종 탈수량은 고분자 용액에 침지시 더 컸다 고장성 용액에 감자절편을 침지시켜 탈수되는 기작이 두가지 압력(삼투압 분자압착력)에 의해 진행된다고 가정하고 모델을 제안하여 감정한 결과 제안된 모델은 고분자 용액에 침지시의 탈수현항을 설명하는데 적합하였다. 모델에서 구해진 압력인자(ΔP)와 농도인자(a)는 온도(T)와 농도(C) 의 함수로 표현되며 계수의 탄력성 검정결과 농도에 대한 의존성이 더 큰 것으로 나타났다.

• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.181-190
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• 2005

Rheological characterisation of flocculated kaolinite pulps has been undertaken to elucidate particle interactions underpinning the dewatering behaviour induced by flocculation with polyethylene oxide (PEO), anionic polyacrylamide (PAM A) and their blends. Shear yield stress $(\tau_y)$ analysis indicated that polymer mediated particle interactions were markedly amplified upon shear of PEG based pulps. In contrast, PAM A based pulps showed a significant decrease in yield values upon shear. Steady stress measurements analysed using a modified Ellis model indicated subtle differences between the respective linear viscoelastic plateaus of the pulps. Furthermore, modified shear thinning behaviour was evident in PEG based pulps. Estimation of elastic and viscous moduli (G', G') was made using dynamic stress analysis for comparison with values determined from vane measurements. Despite a noticeable difference in the magnitude of G' between the two methods, similar trends indicating sheared PEG-based pulps to be more elastic than PAM based pulps, were observed. Floc microstructural observations obtained in support of rheological properties indicate that PEG flocculant induces significantly more compact particle aggregation within the clay pulps under shear consistent with the yield stress data, in contrast to PAM A, or indeed unsheared PEG based pulps. Consequentially, sheared PEG based pulps show significantly improved dewatering behaviour. The implications of the results, potential benefits and drawbacks of flocculation with PEG and PAM A are discussed with respect to improvements in current dewatering processes used in the minerals industry.

• Journal of Environmental Impact Assessment
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• v.20 no.2
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• pp.227-234
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• 2011

In the study, CE-QUAL-W2 was used and its examination and correction were conducted targeting 2001 and 2003 when the condition of rainfall was contradicted. Using the proved model in 2003, a scenario was implemented with management of locations for dewatering outlets and actual data for dam management in 1987 when inflow and outflow level were almost same. In case of the scenario which the location of dewatering outlets was 5m higher than usual location, exclusion efficiency for turbid water inflow at the beginning of precipitation was good. In case of the scenario which the location of dewatering outlets was 10m lower than usual location, exclusion efficiency for excluding turbid water remained in a reservoir after the end of precipitation. However, the scenario applying dam management data in 1987, exclusion efficiency was relatively low. In the scenario, power-generating water release spot at EL.57m for first four days after the beginning of precipitation, EL.52m for 5th to 8th and EL.42m from 9th days. An analysis of the scenario reveals that both excessive days exceeded 30 NTU and average turbidity levels were decreased comparing before and after the alteration on outlets. The average turbidity levels were decreased by minimum of 55% to maximum of 70% and 30NTU exceeding days were decreased by 45 days at maximum. Also, since it could exclude most of turbid water in a reservoir before the destatifcation, the risk for turbid water evenly distributed in a reservoir along with turn-over could be decreased as well.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.1
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• pp.85-95
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• 1996

Although the specific resistance to filtration is the most frequently employed means for characterizing dewaterability of a sludge, it presently is not possible to design nor to prediet performance of dewatering facilities using traditional linearized parabolic filtration equation, that is, the specific resistance model because of theoretical and practical inadequacies of the concept. Limitations of the specific resistance model reflect the need to examine fundamental sludge properties and filtration behaviors affecting dewaterability. From this study, two major limitations of the specific resistance model were noted. First, specific resistance values are very dependent on the sludge concentration because of the variations of particle size distribution and cake clogging to occur when surface area mean diameter is less than $25{\mu}m$ for activated sludge, $18{\mu}m$ for water treatment plant sludge. Second, nonparabolic filtration behavior can result from cake clogging, caused by the migration of fine particles into the cake pores, accelated by skin effect with highly compressible sludges.