• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.12
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• pp.921-925
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• 2015

The number of people suffering from renal disease increases every year. One of the most common treatments (clinical care options) for renal diseases is hemodialysis. However it takes a long time and has a high cost. Therefore, the importance of artificial kidney research has risen. Filtering creatinine from blood is one of the prime renal functions. Thus, we designed a novel two channel microfluidic chip focused on that function. In order to bond the individual polydimethylsiloxane layers, we have developed a housing system using acrylic plastic frame. This method has significant advantages in changing filter membranes. We use anodic aluminum oxide for the filter membrane. We analyzed the difference in the absorbance values for various creatinine concentrations using the Jaffe reaction. For the purpose of acquiring a standard equation to quantify the creatinine concentration, we interpolated the measured data and confirmed the concentration of the filtered solution. Through this experiment, we determined how the filtration efficiency depended on the flow rate and creatinine concentration.

• Membrane and Water Treatment
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• v.11 no.4
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• pp.257-274
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• 2020

There are many previous review articles are available to summarize either the characterization methods of effluent organic matter (EfOM) or the individual control treatment options. However, there has been no attempt made to compare in parallel the physicochemical treatment options that target the removal of EfOM from biological treatments. This review deals with the recent progress on the characterization of EfOM and the novel technologies developed for EfOM treatment. Based on the publications after 2010, the advantages and the limitations of several popularly used analytical tools are discussed for EfOM characterization, which include UV-visible and fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), size exclusion chromatography (SEC), and Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). It is a recent trend to combine an SEC system with various types of detectors, because it can successfully track the chemical/functional composition of EfOM, which varies across a continuum of different molecular sizes. FT-ICR-MS is the most powerful tool to detect EfOM at molecular levels. However, it is noted that this method has rarely been utilized to understand the changes of EfOM in pre-treatment or post-treatment systems. Although membrane filtration is still the preferred method to treat EfOM before its discharge due to its high separation selectivity, the minimum requirements for additional chemicals, the ease of scaling up, and the continuous operation, recent advances in ion exchange and advanced oxidation processes are greatly noteworthy. Recent progress in the non-membrane technologies, which are based on novel materials, are expected to enhance the removal efficiency of EfOM and even make it feasible to selectively remove undesirable fractions/compounds from bulk EfOM.

• Clean Technology
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• v.12 no.3
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• pp.151-156
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• 2006

Combined membrane process of ceramic microfiltration (MF) and polymer ultrafiltration (UF) was optimized for the removal of color and total organic carbon (TOC) from textile wastewater. Membrane regeneration was performed for the efficient operation by backflushing and chemical cleaning. Flux of 10.3% increased by the pulse backflushing of 1 second every 2 minutes in ceramic microfiltration. Membrane regeneration of 97% was obtained by chemical cleaning with 0.1% sodium hydroxide in polymer ultrafiltration. The removal efficiency of TOC, color and SS (suspended solid) were 84.6%, 97.4% and 100%, respectively. The combined process was found to be suitable for the removal of color and residual organics from textile wastewater.

• Membrane Journal
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• v.12 no.2
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• pp.90-96
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• 2002

A novel methodology on the calculations of osmotic pressure and gradient diffusion coefficient has been provided ill the present study, by applying a succinct numerical analysis on the experimental results. Although both the osmotic pressure and the gradient diffusion coefficient represent a fundamental characteristic in related membrane filtrations such as microfiltration and ultrafiltration, neither theoretical analysis nor experiments can readily determine them. The osmotic pressure of colloidal suspension has been successfully determined from a relationship between the data of the time-dependent permeate flux, their numerical accumulations, and their numerical derivatives. It is obvious that the osmotic pressure is gradually increased, as the particle concentration increases. The thermodynamic coefficient was calculated from the numerical differentiation of the correlation equation of osmotic pressure, and the hydrodynamic coefficient was evaluated from the previously developed relation for an ordered system. Finally, the estimated gradient diffusion coefficient, which entirely depends on the particle concentration, was compared to the previous results obtained from the statistical mechanical simulations.

• Environmental Engineering Research
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• v.17 no.4
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• pp.185-190
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• 2012

Rejection characteristics of perchlorate ($ClO_4^-$) were examined for commercially available reverse osmosis (RO) and nanofiltration (NF) membranes. A bench-scale dead-end stirred-cell filtration system was employed to determine the toxic ion rejection and the membrane flux. Model water solutions were used to prepare $ClO_4^-$ solutions (approximately, $1,000{\mu}g/L$) in the presence of background salts (NaCl, $Na_2SO_4$, and $CaCl_2$) at various pH values (3.5, 7, and 9.5) and solution ionic strengths (0.001, 0.01, and 0.01 M NaCl) in the presence of natural organic matter (NOM). Rejection by the membranes increased with increasing solution pH owing to increasingly negative membrane charge. In addition, the rejection of the target ion by the membranes increased with increasing solution ionic strength. The rejection of $ClO_4^-$ was consistently higher for the RO membrane than for the NF membrane and $ClO_4^-$ rejection followed the order $CaCl_2$ < NaCl < $Na_2SO_4$ at conditions of constant pH and ionic strength for both the RO and NF membranes. The possible influence of NOM on $ClO_4^-$ rejection by the membranes was also explored.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.403-410
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• 2006

The objective of this study was to evaluate the possibility of sedimentation basin omission when installed hybrid membrane filtration process in the field plant with the capacity of $500m^3/day$ for 11 months in the "G", water purification plant in Seoul. In order to evaluate the possibility of the sedimentation basin omission, we measured the change of DOC by coagulant dosage. Dosage of PAC(power activated carbon) 4mg/L and coagulant($AI_2O_3$ 10%) 1.67mg/L were compatible to meet the water quality. Also according to the experiment without settlement process, optimization G values were determined to be 300/s, 64/s, and 32/s at the mixing tank, the first flocculator and the second flocculator, respectively. The test was performed under the conditions PAC-coagulation-no settlement-MF. As a result, a dosage of 4.0mg/L as PAC and 0.86 to 1.22mg/L as $Al_2O_3$(10%) in the condition of flux of 62.5LMH were determined to keep TMP value less than $1.0kg_f/cm^2$.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.737-744
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• 2016

The investigation of effects on fouling propensity with various viscosity of feed solutions would be better understanding for forward osmosis (FO) performance since the fouling propensity was directly influenced with solution viscosity. Therefore, this study was focused on the FO fouling with model foultants (humic acid, alginate) by altering solution viscosity with change of ionic strength (I.S) and $Ca^{2+}$ concentrations. In the comparison between humic acid and alginate, as expected, the alginate generally caused more severe fouling (almost 35.8 % of flux reduction) based on the solution characteristics (high viscosity) and fouling patterns (coil and gel layer). However, interesting point to note is that the fouling propensity of alginate was more severe even though it was applied with low viscosity of feed conditions (I.S = 20 mM, $Ca^{2+}=1mM$). This might be due to that crossed linked gel layer of alginate on the FO membrane surface could be best formed in the condition of $Ca^{2+}$ presence and higher I.S, and that is more dominant to fouling propensity than the low viscosity of feed solutions.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.997-1006
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• 2009

Organic removal efficiency and methane production rate, a feasibility of power generation from biogas, and the optimum conditions for membrane operation were evaluated for the pilot scale (5 tons/day) two-phase anaerobic digestion coupled with ultra filtration (TPADUF) system fed with garbage leachate. The TPADUF system is consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. When garbage leachate with 150 g/L of TCOD was fed to the TPADUF up to organic loading rate (OLR) of 11.1 g COD/L/d, the effluent TCOD was lower than 6 g/L and the average removal efficiencies of TCOD and SCOD were higher than 95%. The methane composition of the gas was 65%, and the methane yield was 39 $m^3/m^3$ garbage leachatefed, 260 $m^3$/tons $COD_{added}$, or 270 $m^3$/tons $COD_{removed}$, even there was some gas leak. The power production per consumed gas was 0.96 kWh/$m^3$ gas or 1.49 kWh/$m^3$ methane. This lower power production efficiency mainly due to the small capacity of gas engine (15 kW class). The membrane was operated at the average flux of 10 L/$m^2$/hr. When the flux decreased, washing with water and chemical (NaOCl) was conducted to restore the flux. In the TPADUF system, optimum pH could be maintained without alkali addition by recycling the membrane concentrate or mixed liquor of the methanogenic digester to the acidogenic reactor. Also, partial production of methane in the acidogenic reactor had a positive effect on lowering the OLR of the methanogenic reactor.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1629-1637
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• 2015

To develop various usable water from coal seam gas (CSG) water that needs to be pumped out from coal seams for methane gas production, a feasibility study was carried out, evaluating and analysing a recent report (Coal Seam Gas Water Management Policy 2012) from Queensland State Government in Australia to suggest potential CSG water treatment options for fit-for-purpose usable water production. As CSG water contains intrinsically high salinity-driven total dissolved solid (TDS), bicarbonate, aliphatic carbon, $Ca^{+2}$, $Mg^{+2}$ and so on, it was found that appropriate treatment technologies are required to reduce the hardness below 60 mg/L as $CaCO_3$ by setting the reduction rates of $Ca^{+2}$, $Mg^{+2}$ and Na+ concentrations, as well as TDS reduction. Also, Along with fiber filtration and membrane separation, an oxidation degradation process was found to be required. Along with salinity reduction, as CSG water contains organic compounds (TOC: 248 mg/L, $C_6-C_9$: <20 mg/L and $C_{10}-C_{36}$: <60 mg/L), compounds with relatively high molecular weights ($C_{10}-C_{36}$) need to be treated first. Therefore, this study suggests a combined system design with filtration (Reverse osmosis) and oxidation reduction (electrolysis) technologies, offering proper operating conditions to produce fit-for-purpose usable water from CSG water.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.51-59
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• 2003

In this study, the efficiency of M/F(micro filtration) system was investigated about the wastewater generated from the production process of ${\beta}-glucan$. M/F membrane used the pellicon 2 cassette filter module of millipore(USA) for the operation of M/F plant system. Flux was rised as operation pressure increased, and decreased with the operation time. As concentration ratio increased, the recovery of ${\beta}-glucan$, which was remaind in retentate was effective. As the fermentation solution of ${\beta}-glucan$ reused, the conversion ratio was 42.5%, and the status of fermentation was stable. Based on these results, we suggested that permeate was applicable as water reuse in cleaner production technology.