• Journal of Korean Society of Water and Wastewater
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• v.23 no.2
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• pp.207-214
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• 2009

This study examines the optimum filtration conditions in pretreatment of seawater desalination by reverse osmosis. For this purpose, Masan bay seawater is treated through a gravity filter column while $FeCl_3$ is added as coagulant. The conditions of coagulantd osage, media depth, filtration rate, and backwash time are evaluated. The study results show that the filtrate quality improved with increasing coagulant dosage, but head loss rapidly increased. After 4mg/L, the unit filter run volume reduced to less than $200m^3/m^2$. Considering the head loss development, 4mg/L is determined as the optimum dosage. The better filtrate qualities are obtained with depth of 100cm than that of 80cm. The two stage filtration, which outperformed the single stage filtration, is suggested for treatment of Masan bay. The filtration rate of 5m/h is decided as the optimum condition considering the head loss development. At 10m/h, the filtrate quality deteriorated even though the extent was minimal, and head loss increased rapidly. The backwash time of 10 min is decided appropriate.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.251-257
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• 2014

This research is focused on coagulation and sand filtration process as a pretreatment of RO seawater desalination. RO systems require sufficient and reliable pretreatment process to produce superior quality of RO feedwater that can mitigate RO membrane fouling. This experiment was conducted to investigate the effectiveness of coagulation and filtration process under various experimental conditions including different coagulant dose, flocculation mixing intensity and time, turbidity, and filtration rate. The experimental results showed that the optimum pretreatment conditions resulting in lower SDI value suitable for RO feedwater were coagulation pH 6.5, raw water turbidity greater than 4 NTU, and media bed depth greater than 550 mm. However, flocculation mixing intensity, coagulant dose, and filtration rate relatively affected little on the filtration efficiency.

• Journal of Environmental Science International
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• v.5 no.3
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• pp.329-335
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• 1996

This project studies marine Vibrio vulnificus in oysters in the marine environment and attempts to correlate this bacteria's presence within various environmental parameters; we design this study to determine how different storage temperatures affect the survival of V. vuinficus in oysters and whether V. vulnificus is able to persist in oysters after exposure to UV light-disinfected seawater. Experimental depuration systems consist of aquaria containing temperature-controlled seawater treated with UV light and 0.2 ㎛ pore size filtration. Results showed that depuration at temperatures higher than 25℃ caused V. vuinificus counts to increase in oysters. Throughout the process, depuration water contained high concentrations of U vuinificus indicating"that the disinfection properties of UV radiation and 0.2 ㎛ pore size filtration were less than 어e release of V. vuinificus into seawater, In contrast, when depuration seawater was maintained at 10℃, the numbers of V. vuinificus were very little and multiplication in oysters was inhibited.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.4
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• pp.333-337
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• 2014

The purpose of this study is to develop a process technology to produce high hardness concentrated seawater removing chloride ions but containing useful minerals such as magnesium and calcium in the seawater desalination process. In order to make high hardness concentrated seawater, evaporation system is mostly used recently. Because evaporation system requires a large amount of energy consumption, in this study, it was aimed to produce high hardness concentrated seawater using membrane filtration requiring less energy. Nano filtration membranes were used for the experiments, and different types of high hardness concentrated seawater was produced depending on the membranes' specification, the number of times being concentrated, and pressure. As a result, at between 15bar and 20 bar in pressure, in between the second and the third times of concentration, the experiment result showed the best economic efficiency. By the experiment, production of high hardness concentrated seawater seemed to have a good economic feasibility.

• Resources Recycling
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• v.25 no.4
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• pp.3-10
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• 2016

A lot of researches have been carried out on the recovery of resources from the seawater all over the world. The boron concentration in seawater is low about at 4.5ppm, but considering the volume of seawater, the total weight of dissolved boron amounts to about 5.4 trillion tons. The boron is an essential resource in about 300 kinds of industries. Korea has imported all of the boron and spent more than 700 billion won each year. In this article, we introduce the domestic and international research trends and technologies for removing or recovering the boron from wastewater and seawater. Most of the researches have been conducted to remove the boron from the desalination process, and to recover the boron mainly from wastewater and brine. The technique for the recovery of the dissolved boron includes the ion exchange, which is the most representative, the adsorption membrane filtration (AMF), solvent extraction, and so on.

• Journal of fish pathology
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• v.28 no.3
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• pp.125-131
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• 2015

This study was performed to determine the disinfection efficacy of influent seawater by application of mechanical filtration and UV disinfection system (MFUVDS) in decreasing disease outbreak of juvenile olive flounder (Paralichthys olivaceus). Bacterial disinfection rate of influent seawater following the MFUVDS application was 99.27%. Mortalities of the juvenile reared for 4 months were 20~30% lower than those of the control (25.8%~34.9%).

• Journal of Korean Society of Water and Wastewater
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• v.23 no.2
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• pp.215-222
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• 2009

This study compares the performance of the filters with various media in pretreatment of seawater desalination by reverse osmosis. For this purpose, Masan bay seawater is used as raw water. The filter performance is evaluated by the filtrate quality and the head loss development. Five media is selected in this study: anthracite, $Filtralite^{(R)}$, sand, Pumice, $AFM^{(R)}$. These media are used in combination for dual media filter and alone for mono media filter. The comparison results show that NC0.8-1.6 is the best $Filtralite^{(R)}$. The dual media filter of NC0.8-1.6 and sand outperformed other filters in particle removal. The dual media filter of anthracite and sand showed good performance in organic removal. The mono media filter of Pumice produced the similar filtrate quality as the mono media filter of sand although the effective size of Pumice is considerably greater than that of sand. Due to big size, head loss development is maintained slow in the filtration of Pumice.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.205-209
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• 2003

The various pretreatment processes were evaluated for removal of oil pollutants with weathered oil contaminated seawater in a reverse osmosis desalination process. Weathered oil contaminated seawater was made by biodegradation and photooxidation with oil containing seawater. Coagulation, ultrafiltration, advanced oxidation processes and granular activated carbon filtration was used with pretreatment for dissolved organic carbon. Crude oil was removed but. weathered oil contaminated seawater was not removed by biodegradation and coagulation. DOC and E260 was removed with about 20 % and 40 % by membrane filter of cut off molecular weight 500. So, the most of dissolved organic carbon in weathered oil contaminated seawater was revealed that molecular weight was lower than 500. It is difficult to remove DOC in weathered oil contaminated seawater by advanced oxidation processes treatment, but, E260 was removed more high. However, DOC in weathered oil contaminated seawater was easily adsorbed to GAC. It is revealed that DOC was removed by adsorption.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.227-238
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• 2013

The purpose of this study is to develop a process technology to produce high hardness drinking water which meet drinking water standard, remaining useful minerals like magnesium and calcium in the seawater desalination process while removing the sulfate ions and chloride ions. Seawater have been separated the concentrated seawater and desalted seawater by passing on Reverse Osmosis membrane (RO). Using Nano-filtration membrane (NF), We were prepared primary mineral concentrated water that sodium chloride were not removed. By the operation of electro-dialysis (ED) having ion exchange membrane, we were prepared concentrated mineral water (Mineral enriched desalted water) which the sodium chloride is removed. We have produced the high hardness water to meet the drinking water quality standards by diluting the mineral enriched desalted water with deionized water by RO. Reverse osmosis membranes (RO) can separate dissolved material and freshwater from seawater (deep seawater). The desalination water throughout the second reverse osmosis membrane was completely removed dissolved substances, which dissolved components was removed more than 99.9%, its the hardness concentration was 1 mg/L or less and its chloride concentration was 2.3 mg/L. Since the nano-filtration membrane pore size is $10^{-9}$ m, 50% of magnesium ions and calcium ions can not pass through the nano-filtration membrane, while more than 95% of sodium ions and chloride ions can pass through NF membrane. Nano-filtration membrane could be separated salt components like sodium ion and chloride ions and hardness ingredients like magnesium ions and calcium ions, but their separation was not perfect. Electric dialysis membrane system can be separated single charged ions (like sodium and chloride ions) and double charged ions (like magnesium and calcium ions) depending on its electrical conductivity. Above electrical conductivity 20mS/cm, hardness components (like magnesium and calcium ions) did not removed, on the other hand salt ingredients like sodium and chloride ions was removed continuously. Thus, we were able to concentrate hardness components (like magnesium and calcium ions) using nano-filtration membrane, also could be separated salts ingredients from the hardness concentration water using electrical dialysis membrane system. Finally, we were able to produce a highly concentrated mineral water removed chloride ions, which hardness concentration was 12,600 mg/L and chloride concentration was 2,446 mg/L. By diluting 10 times these high mineral water with secondary RO (Reverse Osmosis) desalination water, we could produce high mineral water suitable for drinking water standards, which chloride concentration was 244 mg/L at the same time hardness concentration 1,260 mg/L. Using the linked process with reverse osmosis (RO)/nano filteration (NF)/electric dialysis (ED), it could be concentrated hardness components like magnesium ions and calcium ions while at the same time removing salt ingredients like chloride ions and sodium ion without heating seawater. Thus, using only membrane as RO, NF and ED without heating seawater, it was possible to produce drinking water containing high hardness suitable for drinking water standard while reducing the energy required to evaporation.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.2
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• pp.97-106
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• 2018

In this study, the effect of chemically enhanced backwash(CEB) coping with algal(Heterosigma Akashiwo) inflow was evaluated in the seawater desalination pretreatment process using ceramic membrane. In order to confirm the possibility of long-term filtration operation, the recovery rate of transmembrane pressure(TMP) due to the CEB using NaOCl was examined. When the membrane flow rate was 83.3 LMH, the TMP was maintained within 200 kPa for 84 hours in seawater influent. As the algal counts of 30,000 cell/mL were injected into the influent of seawater, however, the TMP rapidly increased and exceed maximum value. Membrane fouling caused by the algae was very poorly recovered by usual physical backwash. The CEB was performed for 30 min(3 min circulation / 27 min immersion) with 300 mg/L of NaOCl. As a result of the CEB application, it was possible to maintain a stable operating of filtration during 10 days and the average recovery rate of TMP by the CEB was 98.1%. It has been confirmed that the CEB using NaOCl is very effective in removal of membrane fouling by algae, resulted in stable membrane filtration for the long-term operation.