• Journal of Environmental Science International
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• v.25 no.11
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• pp.1467-1474
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• 2016

In response to the water shortage problem, continued attempts are being made to secure consistent and reliable water sources. Among various solutions to this problem, wastewater effluent is an easy way to secure the necessary supply, since its annual output is consistent. Furthermore, wastewater effluent has the advantage of being able to serve various purposes, such as cleaning, sprinkling, landscaping, river management, irrigation, and industrial applications. Therefore, this study presents the possible use of reclaimed industrial wastewater treated with Birm filters and a UF membrane, along with an analysis on membrane fouling. The preprocessing stage, part of the reclamation process, used Birm filters to minimize membrane fouling. Since this study did not consider heavy metal levels in the treated water, the analyses did not include the criterion for irrigation water quality. However, the wastewater reclaimed by using Birm filters and a UF membrane met every other requirement for reclaimed water quality standards. This indicated that the treated water could be used for cleaning, channel flow for maintenance, recreational purposes, and industrial applications. The analysis on the fouling of the Birm filter and UF membrane required the study of the composition and recovery rate of the membrane. According to SEM and EDX analyses of the UF membrane, carbon and oxygen ion composition amounted to approximately 57%, whereas inorganic matter was not detected. Furthermore, the difference in the recovery rates of the distressed membrane between acidic and alkaline cleaning was more than ~78%, which indicated that organic rather than inorganic matter contributed to membrane fouling.

• Membrane Journal
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• v.18 no.1
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• pp.35-43
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• 2008

In this study, we tried to solve membrane fouling with membranes made by fine nano-particle in MBR process. And we confirmed good fouling resistance in pilot test. In this test, we confirmed our membrane with titania out-standing quality by testing in the pilot long-term test by comparing to other company product. Our membrane keep up steadily $20{\sim}25 L/m^2{\cdot}hr$ high flux in $7,000{\sim}13,000mg/L$ MLSS high sludge concentration. In addition to this quality, we studied membrane flux character related membrane arrangement, membrane-air line arrangement, air-line hole size, cleaning solution concentration, treatment method, etc. Using the optimization of this additional parameter, we tried to search method of maximizing membrane quality.

• Membrane Journal
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• v.31 no.3
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• pp.170-183
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• 2021

Fouling has continued to be a problem that hinders the effectiveness of membrane properties. To solve this problem of reducing fouling effects on membrane surface properties, different and innovative types of membrane patterning has been proposed. This article reviews on the progress of patterned membranes and their separation process concerning the fouling effects of membranes. The types of separation processes that utilize the maximum effectiveness of the patterned membranes include nanofiltration (NF), reverse osmosis (RO), microfiltration (MF), ultrafiltration (UF), and pervaporation (PV). Using these separation processes have shown and prove to have a major effect on reducing fouling effects, and in addition, they also add beneficial properties to the patterned membranes. Each patterned membrane and their separation processes gave notable results in threshold towards flux, salt rejections, hydrophilicity and much more, but there are also some unsolved cases to be pointed out. In this review, the effects of patterned membrane for separation processes will be discussed.

• Membrane and Water Treatment
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• v.9 no.4
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• pp.263-271
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• 2018

The objective of this work was to analyze organic matter removal, nitrification, biomass growth and membrane fouling in a submerged flat-sheet membrane bioreactor, fed with synthetic wastewater, of similar composition to the effluents generated in a fish meal industry. After biomass acclimatization with saline conditions of 12 gNaCl/L and COD/N ratio of 15 in the bioreactor, results showed that the organic matter removal was higher than 90%, for all organic loading rates (0.8, 1, 1.33 and $2gCOD/L{\cdot}d$) and nitrogen loading rates (0.053, 0.067, 0.089 and $0.133gN/L{\cdot}d$) tested during the study. However, nitrification was only carried out with the lowest OLR ($0.8gCOD/L{\cdot}d$) and NLR ($0.053gN/L{\cdot}d$). An excessive concentration of organic matter in the wastewater appears as a limiting factor to this process' operating conditions, where nitrification values of 65% were reached, including nitrogen assimilation to produce biomass. The analysis of membrane fouling showed that the bio-cake formation at the membrane surface is the most impacting mechanism responsible of this phenomenon and it was demonstrated that organic and nitrogen loading rates variations affected membrane fouling rate.

• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.159-168
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• 2002

A lab-scale Reverse Osmosis(RO) membrane reactor was installed to investigate the membrane permeability, characteristics of membrane fouling at each conditions, and performance of elimination at different trans-membrane pressure(TMP) in the liquid fertilizer accumulated system. Experimental setup was divided to three different TMP conditions. As a result of experiment, permeability of RO membrane was proportional to the increase of TMP and temperature. After experiment was completed, two types chemical cleaning(remove the organic foulant and inorganic foulant) was done, and recover rate of permeability was each 99.8, 99.7 and 99.7%, respectively. From this experimental data, membrane fouling could be determined that the most of it was recoverable in this system, and major reason of fouling was concentration polarization. Elimination rate of solute substance in the liquid fertilizer indicated very stable(above 99%), except ammonia nitrogen, and the most stable elimination rate was investigated at the highest TMP condition (Run 3).

• Membrane and Water Treatment
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• v.10 no.2
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• pp.179-189
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• 2019

This study aimed to investigate the effect of temperature and solid retention time (SRT) on membrane fouling in a membrane bioreactors (MBRs). For this purpose, a lab-scale submerged MBR system was used. This system operated at two SRTs of 15 and 5 days, three various temperatures (20, 25 and $30^{\circ}C$) and hydraulic retention time (HRT) of 8 h. The results indicated that decreased the cake layer resistance and increased particles size of foulant due to increasing temperature and SRT. Fourier transform infrared (FTIR) analysis show that the cake layer formed on the membrane surface, contained high levels of proteins and especially polysaccharides in extracellular polymeric substances (EPS) but absorbance intensity of EPS functional groups decreased with temperature and SRT. EEM analysis showed that the peak on the range of Ex/Em=220-240/350-400 in SRT of 15 and temperature of $30^{\circ}C$ indicates the presence of fulvic acid in the cake. In addition, as the temperature rise from 20 to $30^{\circ}C$, concentration of soluble microbial products (SMP) increased and COD removal reached 89%. Furthermore, the rate of membrane fouling was found to increase with decreasing temperature and SRT.

• Membrane and Water Treatment
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• v.7 no.1
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• pp.1-10
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• 2016

Ultrafiltration is known to be one of the most commonly applied techniques in water treatment. Membrane fouling is the main limiting factor in terms of process efficiency and restricting it to the manageable degree is crucial. Natural organic matter is often found to be a major foulant in surface waters. Among many known fouling prevention techniques, the membrane chemical cleaning is widely employed. This study focuses on evaluating the cleaning efficiency of polymeric and ceramic membranes with the use of various chemicals. The influence of cleaning agent type and its concentration, membrane material and its MWCO, and cleaning process duration on the recovery of membrane flux was analyzed. Results have shown that, regardless of membrane type and MWCO, the most effective cleaning agent was NaOH.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.289-296
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• 2010

The purpose of this study is to evaluate various pre-treatment methods and proprieties of water quality for wastewater reuse using reverse osmosis (RO) processes. Secondary effluents were sampled from wastewater treatment plants and lab scale pre-treatments and RO filtration test were conducted systematically. Specifically, different types of pre-treatments, such as coagulation, microfiltration and ultrafiltration, were employed to evaluate the removal efficiency of particle and organic matters which may affect the membrane fouling rate. RO process was later added to eliminate trace amounts of remaining organic matters and salt from the raw water for wastewater reclamation. The permeate through the RO process satisfied water quality regulations for industrial water uses. The experimental results showed that the initial fouling tendency differed not only by the feed water properties but also by the membrane characteristics. Membrane fouling was greater for the membranes with large surface roughness, regardless of the hydrophobicity and zeta potentials. Thus both careful consideration of pre-treatment options and proper selection of RO membrane are of paramount importance for an efficient operation of wastewater treatment.

• Membrane Journal
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• v.25 no.3
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• pp.256-267
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• 2015

The goal is to compare two different aeration strategies for a pilot scale operation of submerged microfiltration with respect to the minimization of membrane fouling. A constant aeration (65 L/min) was examined parallel with a step-wise increase in airflow rate (40 to 65 L/min). The airflow rate was stepped to a higher rate every 5 min and the step-aeration cycles were repeated at regular intervals of 15 min. The comparative filtration runs were conducted with synthetic water containing powdered activated carbon (~10 g/L) and/or kaolin (~20 g/L) at a constant flux of 80 LMH. The extent and mechanisms of fouling in the microfiltration were identified by determining hydraulic resistance to filtration and the fouling reversibility after cleaning. Results showed that the step-aeration effectively alleviated fouling in the microfiltration of synthetic water compared to when using constant aeration. A substantial decrease in fouling was achieved by combining with coagulation using aluminum salts regardless of the aeration strategies. The constant aeration resulted in increased pore blocking likely due to increased accumulation of particles on the surface of membrane.

• Membrane Journal
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• v.24 no.4
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• pp.276-284
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• 2014

In this study, a hydrophobic polyvinylidene fluoride (PVDF) membrane was modified by coating neutral hydrophilic poly(vinyl alcohol). The flux of pure water was measured and then fouling test was conducted with bovin serum albumin (BSA) as model protein foulant. As a result, the experiments showed that pure water flux was decreased but anti-fouling property was significantly enhanced. Pure water flux with increasing molecular weights of the polymer was decreased and fouling resistance was enhanced. Also, Pure water flux with increasing solution concentration was decreased and fouling resistance was enhanced. It is probably due to the increase in hydrophilicity and decrease in roughness of the membrane surface, as revealed by contact angle and AFM analysis.