• Journal of the Korean Society of Visualization
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• v.13 no.2
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• pp.16-21
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• 2015

Concentration polarization(CP) phenomena show great potential on desalination technology. As we can control the dimension of silicon based nanochannel system, it can be used to model ion exchange membrane. In this study, to investigate the effect of nanochannel number and working conditions on the CP based desalination process, nanochannel based microfluidic system is fabricated. First, we optimized nanochannel number and working conditions to conduct visualization study on CP based desalination process. Second, we visualized the desalination process with fluorescent dye in the desalination chip. We also visualized that the particles also can be removed by the CP based desalination process.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.4
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• pp.401-408
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• 2016

Desalination is getting more attention as an alternative to solve a global water shortage problem in the future. Especially, a desalination technology is being expected as a new growth engine of Korea's overseas plant business besides one of the solutions of domestic water shortage problem. In the past, a thermal evaporation technology was a predominant method in desalination market, but more than 75% of the current market is hold by a membrane-based reverse osmosis technology because of its lower energy consumption rate for desalination. In the future, it is expected to have more energy efficient desalination process. Accordingly, various processes are being developed to further enhance the desalination energy efficiency. One of the promising technologies is a desalination process combined with Pressure Retarded Osmosis (PRO) process. The PRO technology is able to generate energy by using osmotic pressure of seawater or desalination brine. And the other benefits are that it has no emission of $CO_2$ and the limited impact of external environmental factors. However, it is not commercialized yet because a high-performance PRO membrane and module, and a PRO system optimization technology is not sufficiently developed. In this paper, the recent research direction and progress of the SWRO-PRO hybrid desalination was discussed regarding a PRO membrane and module, an energy recovery system, pre-treatment and system optimization technologies, and so on.

• Environmental Engineering Research
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• v.20 no.3
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• pp.285-289
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• 2015

Complicated and expensive seawater desalination technology is a big challenge in boron removal process. Conventional seawater desalination process of coagulation utilized for pre-treatment is difficult to remove boron. Boron can be removed more effectively in Reverse Osmosis (RO) process than any other processes. In this study, a coagulant with the name Mineral Cluster was examined its boron removal ability. Boron removal efficiency of Mineral Cluster depended on pH value and Mineral Cluster dosage. Desalination process combines the pre-treatment process with Mineral cluster diluted at the ratio of 1:2500 and the RO membrane process. The original sea water could be desalinated to drinking water quality, 1 mg/L, without any pH adjustments. Therefore, if the Mineral cluster is added without any other chemicals for adjusting pH, the desalination process would be much safer, efficient and economical.

• Environmental Engineering Research
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• v.16 no.4
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• pp.227-230
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• 2011

Seawater desalination technology is a complicated and expensive process. Besides salt removal from seawater, thesignificant problem that needs to be solved is boron removal. Boron removal is difficult so it is a considerable challenge for the desalination process. The main technology of this process is reverse osmosis (RO). RO can remove salt and boron more effectively than other technologies. In a conventional seawater desalination process, coagulant is utilized for pre-treatment but it is difficult to remove boron through this stage. In this study, a coagulant called Mineral Cluster was examined for boron removal. Therefore, Mineral Cluster can be considered a potential coagulant for boron removal in seawater desalination technology.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.827-839
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• 2021

Due to climate change and population growth, water scarcity is getting worse all over the world. Among various methods for desalination of seawater, the Multi-Effect Adsorptive Desalination method, which combines the existing Multi-Effect Desalination method and the Adsorptive Desalination method and can produce high-concentration-high-concentration freshwater, is emerging. Because the Multi-Effect Adsorptive Desalination method combines the two different methods, the system becomes complicated and the possibility of failure increases. Therefore, in this study, availability analysis was performed on the Multi-Effect Adsorptive Desalination process. A total of four types of reliability block diagrams were presented, and availability analysis was conducted based on them. The first form of a reliability block diagram is configured in series without any redundancy. The availability of the reliability block diagram composed of the serial system was found to be lower than the required availability. In order to increase availability, the redundancy to pumps and boiler are added to system. As a result of availability analysis, it was confirmed that designing desalination systems with redundancy to pump meets the 93% availability, which is typically required availability for various plants.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.4
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• pp.317-324
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• 2018

SWRO-PRO hybrid desalination technology is recently getting more attention especially in large desalination markets such as USA, Middle East, Japan, Singapore, etc. because of its promising potential to recover a considerable amount of osmotic energy from brine (a high-concentration solution of salt, 60,000 - 80,000 mg/L) and also to minimize the impact of the discharged brine into a marine ecosystem. By the research and development of the core technologies of the SWRO-PRO desalination system in a national desalination research project (Global MVP) supported by Ministry of Land, Infrastructure, and Transport (MOLIT) and Korea Agency for Infrastructure Technology Advancement (KAIA), it is anticipated that around 25% of total energy consumption rate (generally 3 to $4kWh/m^3$) of the SWRO desalination can be reduced by recovering the brine's osmotic energy utilizing wastewater treatment effluent as a PRO feed solution and an isobaric pressure exchanger (PX, ERI) as a PRO energy converter. However, there are still several challenges needed to be overcome in order to ultimately commercialize the novel SWRO-PRO process. They include system optimization and integration, development of efficient PRO membrane and module, development of PRO membrane fouling control technology, development of design and operation technology for the system scaling-up, development of diverse business models, and so on. In this paper, the current status and progress of the pilot study of the newly developed SWRO-PRO hybrid desalination technology is discussed.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.403-408
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• 2017

In these days, wastewater reclamation and seawater desalination play essential role in addressing the challenge of worldwide water scarcity. Particularly, reverse osmosis (RO) for seawater desalination process is commonly used due to less energy consumption than conventional thermodynamic systems. However, membrane fouling and electrical energy consumption during operation of RO system for seawater desalination haver continued to be a obstruction to its application. In this study, therefore, wastewater secondary effluent is used for osmotic dilution of seawater. Firstly, fouling behaviour of RO by simulating wastewater effluent in osmotic dilution process was measured and we calculated energy consumption of overall desalination process by theoretical equations and commercial program. Our results reveal that RO membrane fouling can be efficiently controlled by pre-treatment systems such as nano filtration (NF) or forward osmosis (FO) process. Especially FO system for osmotic dilution process is a non-pressurized membrane system and, therefore, the operating energy consumption of overall desalination system was the lowest. Moreover, fouling layer on FO membrane is comparatively weak and reversible enough to be disrupted by physical cleaning. Thus, RO system with low salinity feed water through FO process is possible as a less energy consuming desalination system with efficient membrane fouling control.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.635-643
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• 2016

Gas hydrate (GH)-based desalination process have a potential as a novel unit desalination process. GHs are nonstoichiometric crystalline inclusion compounds formed at low temperature and a high pressure condition by water and a number of guest gas molecules. After formation, pure GHs are separated from the remaining concentrated seawater and they are dissociated into guest gas and pure water in a low temperature and a high pressure condition. The condition of GH formation is different depending on the type of guest gas. This is the reason why the guest gas is a key to success of GH desalination process. The salt rejection of GH based desalination process appeared 60.5-93%, post treatment process is needed to finally meet the product water quality. This study adopted reverse osmosis (RO) as a post treatment. However, the test about gas rejection by RO process have to be performed because the guest gas will be dissolved in a GH product (RO feed). In this research, removal potential of dissolved gas by RO process is performed using lab-scale RO system and GC/MS analysis. The relation between RO membrane characteristics and gas removal rate were analyzed based on the GC/MS measurement.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.555-560
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• 2013

A cost analysis method for pretreament processes of a large scale seawater desalination plant was considered using a cost estimation model, WaTER (Water Treatment Estimation Routine). This model is based on cost functions of U.S. EPA to conduct economic analysis of water treatment facilities. A virtual seawater desalination plant which has pretreatment production capacity of $100,000m^3$ per day was chosen as a model plant. Dual media filtration and microfiltration systems were compared as pretreatment process, and the following reverse osmosis process was modeled. As a result, microfiltration showed a price competitiveness in condition of operating with reverse osmosis process by reducing the loads of water treatment and membrane cleaning despite it's high annual cost.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.771-778
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• 2013

Gas hydrate (GH) process is a new desalination technology, where GH is a non- stoichiometric crystalline inclusion compounds formed by water and a number of gas molecules. Seawater GH is produced in a low temperature and a high pressure condition and they are separated from the concentrated seawater. The drawback of the GH process so far is that salt contents contained in its product does not meet the fresh water quality standard. This means that the GH process is not a standalone process for seawater desalination and it needs the help of other desalting process like reverse osmosis (RO). The objective of this study is to investigate the effect of GH process on energy saving for RO process in seawater desalination. The GH product water quality data, which were obtained from a literature, were used as input data for RO process simulation. The simulation results show that the energy saving effect by the GH process is in a range of 68 % to 81 %, which increases as the salt removal efficiency of the GH process increases. Boron (B) and total dissolved solids (TDS) concentrations of the final product of the hybrid process of GH and RO were also investigated through the RO process simulation to find relavant salt rejection efficiency of the GH process. In conclusion, the salt rejection efficiency of the GH process should exceed at least 78% in order to meet the product water quality standards and to increase the energy saving effect.