• The Journal of Engineering Geology
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• v.30 no.4
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• pp.423-433
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• 2020

Direct current (DC) electric fields have been used for electro-osmotic dewatering. Under DC conditions, however, the electrical contact resistance between the electrode and the dewatering material increases considerably during the process of dewatering. Such a circumstance hinders the continuation of effective electro-osmotic dewatering. To reduce this hindrance, an applied pulse electric field with periodic reversals of the electrode polarity should improve electro-osmotic dewatering. In this study, electro-osmotic dewatering under pulse conditions was experimentally investigated for electrode polarity reversals. During the dewatering process, the pulse electric field was able to reduce the hindrance caused by the DC, resulting in an increased final dewatered amount relative to that under a DC electric field. For a constant applied voltage, the reversed polarity condition, under which the electric current passing through the material was almost unchanged with time, yielded the maximum final dewatered amount. This technique can be used to enhance drainage from a water storage facility during a period of extreme drought and the seawater desalination plants using reverse osmosis in drought stricken coastal regions.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.364-370
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• 2016

In this paper, the technique that determines efficient process combinations for the ultrapure water production was studied. The ultrapure water is one of the industrial water used in industrial activity and required in the advanced technology integrated industry. It is produced by combined process including filtration, ion exchange processes, the reverse osmosis (RO) process, degassing (DG) process and UV-oxidation (UVox) process. An ultrapure water production process consists of 15-20 different water treatment unit process. In this study, a pilot plant was built and operated to research the design parameters for the individual process. Through the pilot plant operation, 19 effective combinations were optimized among various processes. And then, 11 of them satisfied the final quality of the ultrapure water. The stability and economic feasibility were evaluated about the final 11 process combinations.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.06a
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• pp.45-58
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• 1994

Over the last 20 years, membrane separation processes, such as reverse osmosis, ultrafiltration and microfiltration, have been widely adopted by different industries. Commercial uses of membrane have displaced conventional separation processes, such as distillation, evaporation, precoat filter and so on. Membrane separation processes are often more capital and energy efficient when compared with conventional separation processes. Membrane devices and systems are almost always compact and modular. These are the well-known advantages of membrane separation processes. The disadvantage of the membrane process is that the process does not have scale merit and thus the membrane process is suitable for the small and middle size applications. Energy saving is, of course, the biggest advantage of the membrane process, and in many industries the membrane processes are employed because of this reason. Membrane process has other big advantage. In many applications membrane processes provide much higher quality of product than conventional processes. The example is ultrapure water production by membrane processes in semiconductor industry. Conventional technologies never offer such good quality of pure water. If you can obtain both energy saving and higher quality of product at the same time by membrane processes, this is the best application of membrane processes. One example is the concentration of orange juice by membrane, which has already been commercialized in Japan. Comparing with the conventional vacuum evaporation process, juice concentrated by the membrane process has much better taste and flavor and the energy consumption in the membrane process is much less than the evaporation process. In this paper, first membrane separation technology will be classified and then Japanese membrane manufacturers and new modules and devices under development in Japan will be introduced. Fourth energy saving in membrane process will be discussed and finally practical applications of membrane processes in Japan will be shown.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.16-24
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• 2004

The reduction of paper machine water usage is precursor to the water system closure of any mills. This reduction in water consumption reduces the loss of solids; especially fine particulates and their surface adsorbed chemical additives, from mills, which causes an inevitable increase of fine materials in papermaking systems. Also the reduction of paper machine water usage causes substantial increase of organic and inorganic substances in process water. The deterioration of the papermaking process water quality accompanying the reduction of papermaking system closure can be a prime source of the aggravation of paper quality and process efficiency. It is of great importance for paper mills to investigate the influence of the level of papermaking system closure on the paper properties and process runnabililty before implementing process closure. To predict the changes in paper properties at different levels of system closure, highly cotaminated white water was prepared using reverse osmosis technology and used to prepare handsheets from fine paper and newsprint stocks. Results showed that the quality of process water affects the strength. Preparation of highly contaminated process water and handsheet forming with headbox stocks provided important criteria to determine the relationship between the qualities of process water and paper products.

• Korean Journal of Microbiology
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• v.50 no.2
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• pp.128-136
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• 2014

Acyl homoserine lactone (AHL) lactonase has been proved to be the AHL-degrading enzyme with the highest substrate specificity for AHL molecules and has shown a considerable potential as low-cost and efficient quorum quenching (QQ) technique. However, few studies focused on its inhibitory effect on biofilm formation which is also a quorum sensing (QS)-regulated phenomenon. In this study, QQ activity of six isolates from biofouled reverse osmosis membranes was studied using Chromobacterium violaceum CV026 and Agrobacterium tumefaciens NTL4 as biosensors under various conditions. All of the isolates belonged to the genus Bacillus and showed QQ activity regardless of the acyl chain length or substitution of AHL molecule. The isolates were capable of significantly inhibiting biofilm formation (46.7-58.3%) by Pseudomonas aeruginosa PAO1 and produced heat-sensitive extracellular QQ substances. The LC-MS analysis of the QQ activity of a selected isolate, RO1S-5, revealed the degradation of N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12 AHL) and the production of corresponding acyl homoserine (3-oxo-C12-HS), which indicated the activity of AHL lactonase. The broad AHL substrate range and high substrate specificity suggested that the isolate would be useful for the control of biofilm-related pathogenesis and biofouling in industrial processes.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.808-813
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• 2015

Boron is difficult to be removed from seawater by simple RO (reverse osmosis) membrane process, because the size of boric acid ($B(OH)_3$), the major form of aqueous boron, is as small as the nominal pore size of RO membrane. Thus, the complexation of boric acid with polyols was suggested as an alternative way to increase the size of aqueous boron compounds and the complexation behavior was investigated with Raman spectroscopy. As a reference, the Raman peak for symmetric B-O stretching vibrational mode both in boric acid and borate ion (${B(OH)_4}^-$) was selected. A Raman peak shift ($877cm^{-1}{\rightarrow}730cm^{-1}$) was observed to confirm that boric acid in water is converted to borate ion as the pH increases, which is also correctly predicted by frequency calculation. Meanwhile, the Raman peak of borate ion ($730cm^{-1}$) did not appear as the pH increased when polyols were applied into aqueous solution of boric acid, suggesting that the boric acid forms complexing compounds by combining with polyols.

• Journal of Animal Science and Technology
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• v.52 no.3
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• pp.213-220
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• 2010

This study was executed to investigate the effects of drinking deep sea water treated by reverse osmosis process (RO-DSW) on growth performance, nutrient utilizability, relative weight of lymphoid organs and the concentration of serum immunoglobulin G (IgG) in broiler chickens. A total of 200 one day old broiler chickens (Ross 308) were equally and randomly distributed into 10 ground floor pens (20 chicks per pen, 5 pens per treatment) bedded with rice-husks. The broilers were offered either fresh tap water (Control) or RO-DSW for 28 days (from d 6 to d 33) as the drinking water. The same basal phase 1 diet for first 2 weeks and phase 2 diet for last 2 weeks were offered ad libitum to the birds. The RO-DSW was prepared by diluting 1:20 ratio with deionized water before offering to chickens. The diet for control birds was supplemented with 0.21 % of food-grade salt to satisfy salt need of the birds. Broiler feeding study resulted that there were no differences in amount of water consumption, mortality and FCR between RO-DSW and control chickens. However, feed intake and body weight gain were increased (p<0.05) by RO-DSW drinking. There was no (p>0.05) difference in nutrients utilizability between RO-DSW and fresh water drinking. There were no (p>0.05) differences in the immune response between the control and treatment group. The serum IgG levels were 3.01 vs 2.87 mg/ml and the relative weights of spleen, thymus and bursa of Fabricius were 0.23, 0.18 and 0.20 vs. 0.20, 0.17 and 0.14 for RO-DSW vs. control birds, respectively. The immune responses were tended to be improved by RO-DSW drinking. This study showed an improvement in weight gain and feed intake that could be induced by RO-DSW drinking, although it is difficult to explain the reasons of the improvement at this moment. This study implied that RO-DSW could be successfully used as drinking water to broiler chickens.

• Journal of Animal Environmental Science
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• v.16 no.1
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• pp.51-60
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• 2010

This experiment was conducted to investigate the effects of concentrated pig slurry separated from membrane filter and by environment-friendly agro-materials mixtures on growth of lettuce in hydroponics. The swine waste treatment system having a ultra filtration and a reverse osmosis process was designed in this study. Filtration of pig slurry was necessary to prevent the hose clogging in hydroponics. Primary separation using ultra filter was followed by concentration by RO (Reverse Osmosis). The concentrated pig slurry (CS) was mixed by five different environment-friendly agro-materials mixtures. The chemical nutrient solution was the solution of National Horticulture Research Station for the growth of lettuce. The concentration of nutrient solution in hydroponics was adjusted a range of 1.5 mS/cm in EC. The concentrated pig slurry was low in phosphorus(P), suspended solid and heavy matal, but rich in potassium (K). The concentrated slurry was lowest in the growth characteristics of leaf lettuce. And also SPAD value in leaf was reduced in plot treated with concentrated slurry. But the growth of lettuce in the mixtures plot (CS+BM+AA, CS+BM+AA+SW) in hydroponics was significantly high compared to concentrated slurry. The fresh yield of lettuce was 78, 84% that of nutrient solution as 131.9, 142.2g in plot of CS+BM+AA and CS+BM+AA+SW, respectively. Our studies have shown that it is possible to produce organic culture using concentrated slurry and environment-friendly agro-materials mixture, although growth is slower than when using a conventional inorganic hydroponic solution.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.48-54
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• 1998

Korea becomes one of the countries which suffer from water shortage. It is expected that its water shortage in the early 2000's will be more than 10% of the annual demand. The shortage problem is more serious in the coastal areas where many industry complex locate. To solve the shortage problem, seawater desalination gets more attention as an alternative water supply source since Korea is surrounded by sea on its three sides. For potential application of seawater desalination in Korea, an economic analysis was conducted using cost data for the plants in the Middle Ease areas, The United states and others. The study is to provide a basis for the government to establish a strategy for promoting seawater desalination in Korea. It is discussed that the Reverse Osmosis (RO) process gets cheaper over times than the thermal processes of Multi-stage Flash Distillation (MSF) and Multi Effect Distillation (ME), especially in case where the capacity is less than about 50,000 ton/day. The unit cost of RO seawater is analyzed about US$1.35/ton in 1990 price. Since the Desalination plant can be operated regardless of weather conditions, industries in Korea's coastal areas which suffer from frequent droughts and water shortages are recommended to look into this option with more attention.

• Membrane Journal
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• v.1 no.1
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• pp.78-95
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• 1991

Water factory 21(WF 2) in Orange County California, is a advanced wastewater treatment(AWT) plant designed to reclaim biologically treated munidpal wastewater for injection into a seawater barrier system. Processes included are lime treatment air stripping, filtration, activated carbon adsorption, reverse osmosis(RO), and chlorination. The effectiveness of each treatment process is presented including pretreatment, RO dimineralization. The data collected show that the processes, including RO, used at WF-21 are capable of producing a very high quality water on a reliable basis. Treatment reduced all contaminants, to levels below national primary drinldng water regulation maximum contaminant levels. It was found that lime clarified secondary effluent can be used as feedwater to a RO dimineralizer. Experiments with new low pressure membrane(250psi) show great potential for reducing RO cost.