• Environmental Engineering Research
• /
• v.24 no.2
• /
• pp.263-270
• /
• 2019

Palm oil mill effluent (POME) is the largest pollutant discharged into the rivers of Malaysia. Thus UF membrane study was conducted to investigate the effect of pressure and stirring speed on performance of POME treatment and fouling of membrane. Two types of membrane polyethersulfone (PES) and regenerated cellulose (RC) with molecular weight cut-off (MWCO) 5 and 10 kDa were used in this study. Results showed that, as pressure increased, fouling increased however permeate quality improved, the best pressure was 1.0 bar, where the fouling was not too high and produce good permeate quality. As stirring speed increased, fouling reduced and permeate quality improved, however, when stirring speed increased from 600 rpm to 800 rpm, there was no significant improvement on the permeate quality. Therefore, the best condition was at 1.0 bar and 600 rpm. PES membrane with MWCO 5 kDa showed the best permeate quality, even fouling slightly higher than RC membrane. The permeate quality obtained were analyzed in term of dissolved solid, turbidity, suspended solid, biological oxygen demand ($BOD_5$) and chemical oxygen demand (COD) were 538 mg/L, 1.02 NTU, < 25 mg/L, 27.7 mg/L and 62.8 mg/L, respectively with dominant type of fouling is cake resistance. Thus, it can be concluded water reuse standard was successfully achieved in terms of $BOD_5$ and suspended solid.

• Membrane Journal
• /
• v.9 no.4
• /
• pp.209-214
• /
• 1999

The purpose of this research was to investigate the permeation properties of each stage in three stage reverse osmosis system for cold-mill wastewater reuse. After construction of the three staged pilot plant which had 75% recovery and equipped with seven plate-and-frame modules, the change of each stage's penneate flow and quality were investigated in the process of membrane fouling. The order of average permeate flow was first, second, and third stage at the beginning. As the operation time passed, the permeate flow of first stage was decreased, the second stage was maintained steadily, and the third stage was increased. Accordingly, the fouling was initiated at the first stage and then progressed to the second and third stage. The first stage's permeate quality showed the best and the second and third stage was the next in that order. And the order of quality was maintained during the test periods. Therefore, the permeate quality was not affected by membrane fouling.

• Korean Journal of Food Science and Technology
• /
• v.25 no.4
• /
• pp.321-326
• /
• 1993

Membrane separation technology with polymeric membranes for the effective separation and energy conservation has emerged to be a new technology for separation in recent years. In this research, the reverse osmosis process was applied to the concentration process of clarified apple juices. The changes of concentration and permeate flux of apple juice in this process were measured at different membrane characteristics, operating pressures, temperature and flow rate. And the changes of quality were also measured at different pressures. The prediction model for the permeate flux based on these data was established. Generally, the osmotic pressure increased as the concentration of the feed increased in the RO process, which caused a reduction of permeate flux. The changes of permeate flux were not much dependent on temperature and flow rate, but very much dependent on pressure. The most effective factor in increased permeate flux was found to be the operating pressure, followed by temperature and flow rate. The final prediction model for the permeate flux was developed by the $SPSS^x$ computer program. The result showed that recovery of sugar was not affected by processing pressures, but the percentage recovery of total flavor was increased with increasing pressure.

• Membrane and Water Treatment
• /
• v.8 no.1
• /
• pp.1-18
• /
• 2017

In this study, reuse of biologically treated wastewater of denim washing and dyeing industry has been evaluated by membrane technologies. After that experiments were carried out at laboratory scale in textile dyeing unit by using obtained permeate water samples on 100% cotton based raw fabric belonging to examined industry. During membrane experiments, two different UF (UC100 and UC030) and two different NF (NP010 and NP030) were evaluated under alternative membrane pressures. In permeate water obtained on selected samples, conductivity at the range of $1860-2205{\mu}S/cm$, hardness at the range of 60 to 80 mg/L, total color at the range of 2.4 to 7.6 m-1 and COD at the range of 25-32 mg/L was determined. The following analyzes were performed for the dyed fabrics: perspiration fastness, rub fastness, wash fastness, color fastness to water, color fastness to artificial light, color measurement through the fabric. According to analysis results, selected permeate water have no negative impact on dyeing quality. The study showed that membrane filtration gave good performance for biologically treated textile wastewater, and NF treatment with UF pre-treatment was suitable option for reuse of the effluents.

• Membrane and Water Treatment
• /
• v.6 no.1
• /
• pp.77-94
• /
• 2015

Ultrafiltration membranes have several advantages over conventional drinking-water treatment. However, this technology presents major limitations, such as irreversible fouling and low removal of natural organic matter. Fouling depends heavily on the raw-water quality as well as on the operating conditions of the process, including flux, permeate recovery, pre-treatment, chemical cleaning, and backwashing. Starting with the premise that the optimisation of operating variables can improve membrane performance, different experiments were conducted in a pilot plant located in Granada (Spain). Several combinations of permeate and backwashing flow rates, backwashing frequencies, and aeration flow rates were tested for low-quality water coming from Genil River with the following results: the effluent quality did not depend on the combination of operating conditions chosen; and the membrane was effective for the removal of microorganisms, turbidity and suspended solids but the yields for the removal of dissolved organic carbon were extremely low. In addition, the threshold transmembrane pressure (-0.7 bar) was reached within a few hours and it was difficult to recover due to the low efficiency of the chemical cleanings. Moreover, greater transmembrane pressure due to fouling also increased the energy consumption, and it was not possible to lower it without compromising the permeate recovery. Finally, the intensification of aeration contributed positively to lengthening the operation times but again raised energy consumption. In light of these findings, the feasibility of ultrafiltration as a single treatment is questioned for low-quality influents.

• Korean Membrane Journal
• /
• v.9 no.1
• /
• pp.12-17
• /
• 2007

We performed periodic water-back-flushing using permeate water to minimize membrane fouling to enhance permeate flux in tubular ceramic microfiltration system for water treatment of high turbid source. The filtration time (FT) = 2 min with periodic 6 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume $(V_T)\;=\;6.805L$. Also in the result of BT effect at fixed FT = 10 min and BT (back-flushing time) = 20 sec showed the lowest value of $R_f$ and the highest value of $J/J_o$, and we could obtain the highest $V_T\;=\;6.660\;L$. Consequently, FT = 2 min and BT = 6 sec could be the optimal condition in water treatment of high turbid source above 10 NTU. However, FT = 10 min and BT = 20 sec was superior to reduce operating costs because of lower back-flushing frequency. Then the average quality of water treated by our tubular ceramic MF system was turbidity of 0.07 NTU, $COD_{Mn}$ of 1.86 mg/L and $NH_3-N$ of 0.007 mg/L.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.6
• /
• pp.581-589
• /
• 2005

Recently, membrane processes have been replacing the conventional processes for waste water treatment to produce better quality of effluent and to meet more stringent regulations because of water shortage. However, using membrane processes for water treatment has confronted with fouling and difficulty in treating dissolved organic pollutants. In this study, membrane process equipped with crossflow microfiltration is combined with coagulation process using alum and PAC to improve permeability and treatment efficiency. The effects of coagulant dosage and optimum membrane operating conditions were investigated from measurement of permeate flow, cumulative volume, total resistance, particle size, dissolved organic pollutant, dissolved aluminium and quality of effluent. Characteristic of PAC coagulation was compared with that of alum coagulation. PAC coagulation reduced membrane fouling because of forming larger particle size and increased permeate velocity and cumulative volume. Less dissolved organic pollutants and dissolved aluminum made decreasing-rate of permeate velocity being lowered. At using $0.2\;{\mu}m$ membrane, cake filtration observed. At using $0.45\;{\mu}m$ membrane, there was floc breakage due to shear stress occurred born circulating operation. It made floc size smaller than membrane pore size, which subsequently to decrease permeate velocity and to increase total resistance. The optimum coagulation dosage was $300{\pm}50\;mg/L$ for both alum and PAC. PAC coagulation was more efficiently used with $0.2\;{\mu}m$ membrane, and the highest permeate flux was in using $0.45\;{\mu}m$membrane. The greatest efficiency of treatment was as follows; turbidity 99.8%, SS 99.9%, $BOD_5$ 94.4%, $COD_{Cr}$ 95.4%, T-N 54.3%, T-P 99.8%.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.4
• /
• pp.1391-1398
• /
• 2010

Reuse feasibility of MBR effluent of S Electronic Company's organic wastewater as a LCD process water was investigated by a $32m^3/d$ pilot-scale RO membrane process. The effects of operating pressure and permeate flux at constant 85% recovery of RO membrane process using MBR effluent were analyzed for transmembrane pressure and period for CIP by membrane fouling as well as rejection of TOC and conductivity. MBR effluent requires additional treatment to meet the LCD process water quality criteria of TOC<1 mg/L and conductivity<$100{\mu}S/cm$ which is stringent as compared with those of conventional reuse water quality criteria. The RO process operated at 85% recovery with stepwise increasing of permeate fluxes from 12.5 LMH to 22.0 LMH was able to meet LCD process water quality criteria. However, the transmembrane pressure increased and the period of CIP decreased as increasing permeability fluxes due to fouling of RO membrane. The optimum operational conditions of RO membrane process were permeate fluxes of 16.5~18.5 LMH with operating pressure of $6.7{\sim}12.4kgf/cm^2$ and CIP period of 20~25 days at constant 85% recovery.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.5
• /
• pp.588-597
• /
• 2004

In this research, we investigated the variation of transmembrane pressure and permeate water quality with pre coagulation and sedimentation with iron based coagulant and chlorination of feed water for PVDF (polyvinylidene fluoride) based MF membrane filtration. NaCIO was fed to the membrane module with dosage of 0.5mg/L and maintained during filtration. To observe the effect of raw water, three types of raw and processed waters, including river surface water, coagulated water and coagulated-settled water, were applied. In case of river surface water, the transmembrane pressure increased drastically in 500 hours of operation. On the contrary, no significant increase in transmembrane pressure was observed for 1,200 hours of operation for coagulated water and coagulated-settled waters. The turbidity of permeate was lower than a detection limit of equipment for all raw waters. The removal efficiency of humic substances of coagulated water and coagulated-settled water was approximate ten times of that of surface river water. And, the removal efficiency of TOC and DOC was approximate two times of that of surface river water. From the results of plant operation, stable operation was maintained at $0.9m^3/m^2{\cdot}day$ filtration flux through the combination of pre-coagulation and pre-chlorination. However, the water quality of permeate was the best when pre-coagulation-sedimentation process was combined with pre-chlorination.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.6
• /
• pp.613-619
• /
• 2006

The objectives of this research are to evaluate the effect of membrane materials, particulate matter and membrane pore size on permeate flux. It was shown that the removal efficiency of high MW organic matter more than 10 kDa was lower than that of low MW organic matter for $MIEX^{(R)}$ process. For the change of permeate flux by the pretreatment process, $MIEX^{(R)}+UF$ process showed high removal efficiency of organic matter as compared with coagulation+UF processes, but high reduction rate of permeate flux was presented through the reduction of removal efficiency of high MW organic matter. The pretreatment of the raw water significantly reduced the fouling of the hydrophilic membrane, but did not decrease the flux reduction of the hydrophobic membrane. Flux decline on MF process increased due to the pore clogging, while the permeate flux decline of UF process decreased due to the formation of cake layer. It was shown that particle matter was not effect on MIEX+membrane process. But, for coagulation+membrane process, particle matter was important factor on permeate flux.