• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.67-72
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• 1997

To evaluate the effectiveness of water treatment using nanofiltration, ultrafiltration, and microfiltration systems, tapwater contaminated by bacteria and nitrate nitrogen was filtered, and then the rates of removal for many kinds of contaminants were comp.ared and investigated. The rates of turbidity removal by these systems are around 80% all of them. However, nanofiltration system is the most effective as hardness removal is 80%, suspended solids 90%, total residual chlorine 90% and nitrate nitrogen 69%. Among nanofiltration, ultrafiltration and microfiltration systems, nanofiltration system is the most stable in flow rate of permeate. Comparing hollow and spiral type of ultrafiltration, microfiltration each, spiral type is more stable than hollow type owing to rinsing effect of brine. The values of pH in ultrafiltration and microfiltration systems are between 7, 0 and 7.5, and that of nanofiltration system is low to 6.2-7.0. The effectiveness of heterotrophic bacteria removal is the most excellent in the nanofiltration system.

• Journal of Climate Change Research
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• v.9 no.1
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• pp.75-80
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• 2018

The problem of water shortages and water related disasters caused by climate change has increased the seriousness of water problems and the importance of water treatment technology capable of securing clean water is expanding. In this study, we analyzed not only the water pollutant generated by the filtration system technology of various water treatment technologies but also the indirect greenhouse gas emissions generation, and analyzed the influence on the environment. The subjects of study are Fabric Filter, Reverse Osmosis System and Pressurized Microfiltration Device which are widely used for water treatment and we analyzed the impact on the environment using the Life Cycle Assessment (LCA) method using the electricity amount necessary for use, the water purification efficiency, the throughput per ton and the cost. The amount of greenhouse gas generated when the Pressurized Microfiltration Device operates for 1 year is $2.15E+04kg\;CO_2-eq$., Fabric Filter is $3.29E+04kg\;CO_2-eq$., and Reverse Osmosis System is $1.68E+05kg\;CO_2-eq$. As a result of analyzing the amount of greenhouse gas generated at the time of purifying 1 ton of the Pressurized Microfiltration Device and the conventional filtration system, the Pressurized Microfiltration Device was $20.5g\;CO_2-eq$., Fabric Filter was $34.7g\;CO_2-eq$., and Reverse Osmosis System was $191.7g\;CO_2-eq$. The amount of greenhouse gas generated was calculated to be 41.0% less than that of the Fabric Filter by the Pressurized Microfiltration Device and 89.3% less than the Reverse Osmosis System. From the viewpoint of climate change, it is necessary to select a filtration system that takes climate change into account, not from the viewpoint of water quality removal efficiency and economic efficiency according to future water treatment applications, and it is necessary to select a water treatment filtration system more researches and improvements will be made for.

• Journal of environmental and Sanitary engineering
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• v.23 no.4
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• pp.13-21
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• 2008

With the rise in membrane applications, residuals management has become a growing challenge for membrane system. The primary residuals of MF/UF (microfiltration/ultrafiltration) system results from the wastes generated during backwashing. Many regulatory agencies, utilities, and water process engineers are unfamiliar with the characteristics and methods for treatment and disposal of membrane residuals. Therefore, this study was performed to investigate the backwash residuals water quality from the pressurized system with and without pre-coagulation, and to suggest approaches for the backwash residuals treatment. Pressurized MF system was installed at Guui water intake pumping station and operated with raw water taken from the Han River. We compared performances with and without the recycling backwash residuals at flux conditions, 50 LMH and 90 LMH with and without pre-treatment (coagulation). Based on the results, recycling of backwash residuals in pressurized system with pre-coagulation showed applicability of backwash residuals managements. Moreover, the recovery rate also increased up to over 99%.

• Membrane Journal
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• v.12 no.3
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• pp.151-157
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• 2002

This research was to demonstrate the Possibility of sewage reuse for industrial purpose with use of membrane system. A bench scale test with microfiltration and reverse osmosis showed that microfiltration in the sewage treatment was not able to remove the soluble salts but 70% suspended solids (SS), suggesting that the treated water could be used as direct cooling water. In addition, the reverse osmosis removed not only soluble salts but also 95% SS, proposing that reverse osmosis-treated water could be used as both indirect cooling water and rinsing water. For a 100 ton/day pilot plant, 20 and 12 elements of microfiltration and reverse osmosis were required, respectively.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.05a
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• pp.31-38
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• 2003

A pilot scale biofilter pretreatment-microfiltration system (BF-MF) was operated to investigate the effect of biofilter treatment in fouling reduction of microfiltration. Biofiltration was expected to reduce the membrane fouling by removal of turbidity and metal oxides. The hollow-fiber MF module with a nominal pore size of 0.1$\mu$m and a surface area of 8m$^2$ was submerged in a filtration tank and microfiltration was operated at a constant flux of 0.5 m/d. Biofiltration using polypropylene pellets was performed at a high filtration velocity of 320 m/d. Two experimental setups composed of MF and BF/MF, i.e., without and with biofilter pretreatment, were compared. Throughout the experimental period of 9 months, biofilter pretreatment was effective to reduce the membrane fouling, which was proved by the result of time variations of trans-membrane pressure and backwash conditions. The turbidity removal rate by biofiltration varied between 40% to 80% due to the periodic washing for biofilter contactor and raw water turbidity. In addition to turbidity, metals, especially Mn, Fe and Al were removed effectively with average removal rates of 89.2%, 67.8% and 64.9%, respectively. Further analysis of foulants on the used membranes revealed that turbidity and metal removal by biofiltration was the major effect of biofiltration pretreatment against microfiltration fouling.

• Korean Membrane Journal
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• v.2 no.1
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• pp.1-8
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• 2000

In Kimchi (a salt-pickled and fermented food) manufacturing industry, the process of brining and rinsing the raw vegetable produces a vast amount of wastewater of high salinity. Instead of expensive and low-efficient conventional treatment system, brining wastewater reuse system was developed using hybrid chemical precipitation/microfiltration. In the microfiltration of chemically treated brining wastewater, comparison of flux, backwashing frequency and energy consumption was made between dead-end and crossflow filtration mode. The optimum location of neutralization step in this system was also discussed in connection with the microfiltration performance. The quality test of Kimchi prepared by the reuse system confirmed the new approach was successful in terms of water/raw material(salt) saving and wastewater reduction.

• KSBB Journal
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• v.9 no.4
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• pp.385-394
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• 1994

Large scale purification to get antifungal antibiotic KRF-001 of 90% purity, was investigated using preparative HPLC. Crude KRF-001 was purified by XAD-7 adsorption chromatography, acid precipitation and microfiltration. Microfiltration was the most effective isolation method of crude KRF-001. The purification methods using C18 chromatography was convenient compared with the conventional methods. Delta PAK C18 column and Bonda PAK C18 column were adapted large scale purification of KRF-001. Gradient system of prep HPLC using Delta PAK C18 column was more effective. With these conditions, final recovery of KRF-001 yielded 77%.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.1
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• pp.101-112
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• 2013

Integrated process with coagulation and microfiltration as an advanced water treatment has been expanded its application in recent years due to its superb removal of particles and natural organic matter. In usual, effectiveness of coagulation sometimes determines performance of the whole system. Several new polymeric coagulants introduced to water utilities for better efficiency were studied in this paper. Three polymeric coagulants (i.e., PACl, PACs, and PAHCs) along with alum were evaluated for removal of natural organic matter, especially for reduction of trihalomethane formation potential, for which regulation has become stringent. Turbidity removal was closely related to pH variation showing the reduced turbidity removal by PACs due to the decreases in the pH of supernants at high doses. The four coagulants showed different organic matter removal during coagulation and affected the removal in microfiltration. For instance, DOC concentration was not reduced by microfiltration when PAHCs were used however 10 % of DOC removal was observed by microfiltration with alum coagulation. Coagulation pretreatment also impacted the THM removals, i.e., approximately 30 % of THMs and 13 % of DOC was removed by microfiltration only, but 40 to 67 % of THMs and 30 % of DOC was removed by the integrated process. Strategies on selection of coagulants are needed depending on characteristics of target pollutants in raw waters.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.595-601
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• 2010

It is evident that Korea will continue its battle with water shortage and alternative program are being taken into action. One of the main actions is reusing 1,800 tons of effluent of 357 sewage treatment plant located nationwide. Therefore this study supplemented ozone oxidation methods that would increase the efficiency of organic oxidation and coagulation. Through this method, fouling will be controled sufficiently by preventing membrane process in the system for advanced sewage treatment. In this study, ozone-coagulation-microfiltration membrane were used. The final removal efficiency of the pretreated water from the result of the ozone-coagulation were 50% of CODcr, 38% of TP and 11% of TOC respectively. Water quality treatment has decreased about 80% for TP. Ozone-coagulation-microfiltration membrane maintains the high flux while decreasing the number of organic matter and the membrane fouling, and reducing the TP. As a result, in order to reuse the water from the sewage, the ozone-coagulation-microfiltration membrane type must be considered in order to achieve the best efficiency.

• Environmental Engineering Research
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• v.22 no.4
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• pp.377-383
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• 2017

A tube-type ceramic membrane for microfiltration was developed, and the membrane module comprised of three membranes was also applied to biological carbon and nitrogen removal processes for post-treatment. Manufacturing the microfiltration membrane was successful with the structure and boundary of the coated and support layers within the membrane module clearly observable. Total kjeldahl nitrogen removal from effluent was additionally achieved through the elimination of solids containing organic nitrogen by use of the ceramic membrane module. Removal of suspended solids and colloidal substances were noticeably improved after membrane filtration, and the filtration function of the ceramic membrane could also easily be recovered by physical cleaning. By using the ceramic membrane module, the system showed average removals of organics, nitrogen, and solids up to 98%, 80% and 99.9%, respectively. Thus, this microfiltration system appears to be an alternative and flexible option for existing biological nutrient removal processes suffering from poor settling performance due to the use of a clarifier.