• Membrane Journal
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• v.9 no.3
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• pp.185-192
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• 1999

The ultrafiltration characteristics of wafer processing wastewater produced from semicon¬ductor industry was investigated for wastewater reuse. Using the pilot-scale ultrafiltration system con¬taining poly sulfone hollow fiber membranes (MWCO : 10,000, 20,000, 30,(00), the membrane performance, such as flux, rejection rate and concentration factor for flux was examined. The SDhs, turbidity, electrical conductivity and concentration of Si particles were measured, and the possibility of permeate reuse was validated from the experimental results. It was shown that the flux was recovered by the sweeping with air and water effectively. The permeate flux of 30,000 MWCO membrane was about 5 times higher than that of 10,000 and 20,000 MWCO membranes. The concentration of Si particle in the saw wastewater was analyzed 3.8-5.6 mg/$\ell$ and that of Si particle in the permeate was analyzed less than 0.2${\mu}g$/$\ell$. This means the rejection of silicon particle was over 96%.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.4
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• pp.259-266
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• 2020

In this study, a pilot-scale (3 ㎥/day) membrane distillation (MD) process was operated to treat digestate produced from anaerobic digestion of livestock wastewater. In order to evaluate the performance and energy cost of MD process, it was compared with the pilot scale (10 ㎥/day) reverse osmosis (RO) process, expected competitive process, under same feed condition. As results, MD process shows stable permeate flux (average 10.1 L/㎡/hr) until 150 hours, whereas permeate flux of RO process was decreased from 5.3 to 1.5 L/㎡/hr within 24 hours. In the case of removal of COD, TN, and TP, MD process shows a high removal rate (98.7, 93.7, and 99% respectively) stably until 150 hours. However, in the case of RO process, removal rate was decreased from 91.6 to 69.5% in COD and from 93.7 to 76.0% in TP during 100 hours of operation. Removal rate of TN in RO process was fluctuated in the range of 34.5-62.9% (average 44.6%) during the operation. As a result of energy cost analysis, MD process using waste heat for heating the feed shows 18% lower cost compare with RO process. Thus, overall efficiency of the MD process is higher then that of the RO process in terms of permeate flux, removal rate of salts, and operating cost (in the case of using waste heat) in treating the anaerobic digestate of livestock wastewater.

• Journal of the Korean Solar Energy Society
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• v.34 no.5
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• pp.23-31
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• 2014

This study was accomplished to get the foundation design data of VMD(Vacuum Membrane Distillation) system for Solar Thermal VMD plant. VMD experiment was designed to evaluate thermal performance of VMD using PVDF(polyvinylidene fluoride) hollow fiber hydrophobic membranes. The total membrane surface area in a VMD module is $5.3m^2$. Experimental equipments to evaluate VMD system consists of various parts such as VMD module, heat exchanger, heater, storage tank, pump, flow meter, micro filter. The experimental conditions to evaluate VMD module were salt concentration, temperature, flow rate of feed sea water. Salt concentration of feed water were used by aqueous NaCl solutions of 25g/l, 35g/l and 45g/l concentration. As a result, increase in permeate flux of VMD module is due to the increasing feed water temperature and feed water flow rate. Also, decrease in permeate flux of VMD module is due to increasing salinity of feed water. VMD module required about 590 kWh/day of heating energy to produce $1m^3/day$ of fresh water.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.339-346
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• 2017

In this study, thermal performance test of VMD module was performed, prior to the construction of the demonstration plant using the vacuum membrane distillation (VMD) module of the capacity of $400m^3/day$ and to the commercialization of the VMD module. For the thermal performance test, the experimental equipment of capacity of $2m^3/day$ was constructed. The permeate flux test and thermal performance test according to feed water conditions such as temperature and flow rate were conducted. The VMD module used in the study was manufactured by ECONITY Co., LTD with PVDF hollow fiber membrane. As a result, the Performance Ratio (PR) of the VMD module showed the maximum value of 0.904 under the condition of feed water temperature of $75^{\circ}C$ and flow rate of $8m^3/h$. PR value of the VMD module using PVDF hollow fiber membrane showed linearly increasing relationship with feed water temperature and flow rate. Also, The permeate flux of the VMD module was analyzed to have maximum value of 18.25 LMH and the salt rejection was 99.99%.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.451-460
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• 2019

Thin film composite membranes incorporated with nano-sized hydrophilic zeolite -A were successfully prepared via interfacial polymerization (IP) on porous blend PES/PAN support for water desalination. The thin film nanocomposite membranes were characterized by SEM, contact angle and performance test with 7000 ppm NaCl solution at 7bar. The results showed that the optimum zeolite loading amount was determined to be 0.1wt% with permeate flux 29LMH.NaCl rejection was improved from 69% to 92% compared to the pristine polyamide membrane where the modified PA surface was more selective than that of the pristine PA. In addition, there was no significant change in the permeate flux of the thin film nanocomposite membrane compared with that of the pristine PA in spite of the formation of the dense polyamide layer. The stability of the polyamide layer was investigated for 15 days and the optimized membrane presented the highest durability and stability.

• Korean Membrane Journal
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• v.11 no.1
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• pp.21-28
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• 2009

We investigated the effect of organic materials on membrane fouling in advanced drinking water treatment by a hybrid module packed with granular activated carbon (GAC) outside multi-channel ceramic microfiltration membrane. Synthetic water was prepared with humic acid and kaolin to simulate natural water resouces consisting of natural organic matter and inorganic particles. Kaolin concentration was fixed at 30 mg/L and humic acid was changed as 2~10 mg/L to inspect the effect of organic matters. Periodic back-flushing using permeate water was performed for 10 sec per filtration of 10 min. As a result, both resistance of membrane fouling (Rf) and permeate flux (J) were influenced highly by concentration of humic acid. It proved that NOM like humic acid could be an important factor on membrane fouling in drinking water treatment. Turbidity and UV254 absorbance were removed up to above 97.4% and 59.2% respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.1
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• pp.13-19
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• 2014

The feed temperature has an effect on the performance during desalination of seawater by membrane separation. When the permeate flux intends to increase using the waste heat, it is necessary to analyze the effect of feed temperature precisely on the membrane performance. The experiments were carried out to investigate the performance of membranes by varying the seawater temperature from $10^{\circ}C$ to $60^{\circ}C$. The increase of permeate flux with increase of feed temperature was interpreted as the change of water viscosity and the membrane itself. While the increase of permeate flux could be predicted by the viscosity change in case of nanoflitration membrane, there exists 30% difference between the experiment data and the prediction by the viscosity change in case of reverse osmosis (RO) membrane, which seems to be due to 8% decrease of the pore size in 60caused by the contraction of membrane with the increase of temperature. Therefore, the desalination of seawater should be carried out within the range that the elevation of temperature does not cause the alteration of membrane itself even for the purpose of increasing the permeate flux.

• Membrane Journal
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• v.6 no.4
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• pp.250-257
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• 1996

Surface crosslinked chitosan composite membranes were prepared with glutaraldehyde and surfuric acid. Effects of neutralization for complex between chitosan and acetic acid and of water permeability for substrate membranes on pervaporation performance were investigated. For ionically crosskinked membranes, effect of active layer thickness on separation factor of water/ethanol mixture was studied. With increasing the water permeability of the substrate, the membrane showed an increased separation factor, while it maintained a constant permeate flux. Neutralized chitosan composite membranes revealed a decreased separation factor and a constant permeate flux. When the thickness of the active layer increased, an optimum crosslinking time to achieve higher separation factor shifted to a prolonged times.

• Applied Chemistry for Engineering
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• v.31 no.1
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• pp.90-96
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• 2020

This paper aims to reuse sewage by a forward osmosis using a blended fertilizer as a draw solution. This work deals with the primary sedimentation basin influent, effluent, and secondary sedimentation basin effluent from J sewage treatment plant. The average permeate water flux was higher in the order of the blend of KCl and NH₄Cl > KCl and NH₄H₂PO₄ > KCl and (NH₄)₂HPO₄, and the reverse solute flux was lower in the order of the blend of KCl and NH₄H₂PO₄ < KCl and NH₄Cl < KCl and (NH₄)₂HPO₄. Regardless of the blended fertilizer, the permeate water flux of the effluent from the secondary sedimentation basin was the highest. The blended fertilizer of KCl and NH₄H₂PO₄ was found to be most useful for the reuse of sewage because it contains nitrogen, phosphorus and potassium, which are the major components of a fertilizer, and has a low reverse solute flux. When the blend of KCl and NH₄H₂PO₄ was used as a draw solution, the average permeate water and reverse solute flux for the secondary sedimentation basin effluent were 12.14 L/㎡hr and 0.012 mol/㎡s, respectively.

• Korean Membrane Journal
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• v.7 no.1
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• pp.34-41
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• 2005

The wastewater discharged from a paper plant was filtrated by 3 kinds of tubular carbon ceramic UF and MF membranes with $N_2$-backflushing. The filtration time (FT) was fixed at 8 min or 16 min, and $N_2$-backflushing time (BT) was changed in 0${\~}$60 sec. The optimal condition was discussed in the viewpoints of total permeate volume ($V_T$), dimensionless permeate flux (J/Jo) and resistance of membrane fouling ($R_f$). In the viewpoints of $V_T$, J/Jo and $R_f$, the optimal $N_2$-BT was 40 sec at both FT for M9 (MWCO: 300,000 Daltons) and C005 ($0.05{\mu}m$) membranes. However, for C010 ($0.1{\mu}m$) it was 10 sec at FT=8 min, and 20 sec at FT=16 min in the viewpoints of J/Jo and $R_f$, and 5 sec at both FT in the viewpoints of $V_T$. It means that the short $N_2$-BT could reduce the membrane fouling and recover the permeate flux sufficiently for MF membrane having a large pore size as C010. Average rejection rates of pollutants were higher than $99.0\%$ for turbidity and $22.8{\~}59.6\%$ for $COD_{cr}$, but rejection rates of total dissolved solid (TDS) were lower than $8.9\%$. Therefore, the low turbidity water purified in our system could be reused for paper process.