• 상하수도학회지
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• 제34권6호
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• pp.403-410
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• 2020

The difficulty of securing freshwater sources is increasing with global climate change. On the other hand, seawater is less affected by climate change and regarded as a stable water source. For utilizing seawater as freshwater, seawater desalination technologies should be employed to reduce the concentration of salts. However, current desalination technologies might accelerate climate change and create problems for the ecosystem. The desalination technologies consume higher energy than conventional water treatment technologies, increase carbon footprint with high electricity use, and discharge high salinity of concentrate to the ocean. Thus, it is critical to developing green desalination technologies for sustainable desalination in the era of climate change. The energy consumption of desalination can be lowered by minimizing pump irreversibility, reducing feed salinity, and harvesting osmotic energy. Also, the carbon footprint can be reduced by employing renewable energy sources to the desalination system. Furthermore, the volume of concentrate discharge can be minimized by recovering valuable minerals from high-salinity concentrate. The future green seawater desalination can be achieved by the advancement of desalination technologies, the employment of renewable energy, and the utilization of concentrate.

• Environmental Engineering Research
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• 제20권1호
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• pp.99-104
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• 2015

The purpose of this study is to evaluate the performance of forward osmosis (FO) system for harvesting microalgae cultivated in secondary sewage effluent. Microalgae species used in this study were chlorella sp. ADE4. The drawing agents used for forward osmosis system were seawater and concentrate of sea water reverse osmosis (SWRO) system. Chlorella sp. ADE4 cultured in secondary sewage effluent illustrated moderate efficiency in removal of total nitrogen (TN) (68%) and superior performance in total phosphorus (TP) removal (99%). Comparison of seawater and SWRO concentrate as drawing agent were made in FO membrane separation of the microalgae. The result from this study depicts that SWRO concentrate is strong drawing agent in FO membrane system providing an average dewatering rate of $4.8L/(m^2{\cdot}hr)$ compared to seawater with average dewatering of $2.9L/(m^2{\cdot}hr)$. Results obtained from this study indicated that FO system could be viable option for harvesting the microalgae for further biodiesel production. SWRO concentrate as a drawing agent could be very important finding in field of membrane technology for disposal of SWRO concentrate.

• 에너지공학
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• 제25권4호
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• pp.1-6
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• 2016

일반적으로 해수담수화플랜트는 크게 두 가지의 문제점을 가지고 있는데, 에너지 비효율성과 해수담수화 후 부산물인 농축수의 해결방안이다. 전자는 태양에너지 등 신 재생에너지원의 활용과 새로운 기술에 대한 꾸준한 연구개발로 상당히 그 효율성이 개선되었으나, 농축수 해결방안에 대한 연구는 아직 미미한 실정이다. 본 논문에서는 많은 에너지를 투입하여 담수와 함께 생산된 농축수의 활용과 관련하여 제염이 가능한 설비의 구축과 그 효용성을 제고하기 위한 미네랄(Mg) 성분 제어에 관하여 제주 MVR해수담수화 플랜트를 중심으로 그 연구 결과를 소개하고자 한다. 플랜트의 정상 작동으로 생산된 농축수에 본 연구의 제염 설비를 적용하여 단계별 소금의 성분 함량을 분석했을 때 Mg 성분 수치가 줄어드는 것으로 보아 미네랄(Mg) 제어가 정상적으로 진행되고 있음을 알 수 있었다. 아울러, 본 MVR해수담수화 플랜트의 에너지 이용의 효율성과 담수 생산 및 농축수 활용에 관하여 그 활용성을 확인할 수 있었다.

• 상하수도학회지
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• 제25권3호
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• pp.399-405
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• 2011

In a desalination technology using RO membranes, chemical cleaning makes damage for membrane surface and membrane life be shortened. In this research cleaning technology using direct osmosis (DO) was introduced to apply it under the condition of high pH and high concentration of feed. When the high concentration of feed is injected to the concentrate side after release of operating pressure, then backward flow occurred from treated water toward concentrated for osmotic pressure. This flow reduces fouling on the membrane surface. Namely, flux of DO was monitored under pH 3, 5, 10 and 12 conditions at feed concentrations of NaCl 40,000 mg/L, 120,000 mg/L and 160,000 mg/L. As a result, DO flux in pH 12 increased about 21% than pH 3. DO cleaning was performed under the concentrate NaCl 160,000 mg/L of pH 12 during 20 minutes. Three kinds of synthetic feed water were used as concentrates. They consisted of organic, inorganic and seawater; chemicals of SiO2 (200 mg/L), humic acid (50 mg/L) sodium alginate (50 mg/L) and seawater. As a result, fluxes were recovered to 17% in organic fouling, 15% in inorganic fouling and 14% of seawater fouling after cleaning using DO under the condition of concentrate NaCl 160,000 mg/L of pH 12.

• 한국수산과학회지
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• 제41권3호
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• pp.163-169
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• 2008

This study investigated the quality of salted mackerel prepared with deep seawater concentrate and salt. The quality of the salted mackerel product prepared with deep seawater was compared to that prepared with surface and intermediate seawater salts, sun-dried salt, and refined salt. After preparing the salted mackerel products using the five salts, the products were stored at $4^{\circ}C$ for 35 days. Quality characteristics compared were the acid value (AV), peroxide value (POV), lipophilic browning, volatile basic nitrogen (VBN), pH, viable cell count, and sensory factors. The deep seawater salted mackerel product had the lowest AV, POV, browning value, and viable cell counts, compared to the others, while it had the highest score in the sensory evaluation.

• Nuclear Engineering and Technology
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• 제41권8호
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• pp.1101-1108
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• 2009

The ocean contains around eighty elements of the periodic table and uranium is also one among them, with a uniform concentration of 3.3 ppb and a relative abundance factor of 23. With a large coastline, India has a large stake in exploiting the 4 billion tonnes of uranium locked in seawater. The development of radiation grafting techniques, which are useful in incorporating the required functional groups, has led to more efficient adsorbent preparations in various geometrical configurations. Separation based on a polymeric adsorbent is becoming an increasingly popular technique for the extraction of trace heavy metals from seawater. Radiation grafting has provided definite advantages over chemical grafting. Studies related to thermally bonded non woven porous polypropylene fiber sheet substrate characterization and parameters to incorporate specific groups such as acrylonitrile (AN) into polymer back bones have been investigated. The grafted polyacrylonitrile chains were chemically modified to convert acrylonitrile group into an amidoxime group, a chelating group responsible for heavy metal uptake from seawater/brine. The present work has been undertaken to concentrate heavy metal ions from lean solutions from constant potential sources only. A scheme was designed and developed for investigation of the recovery of heavy metal ions such as uranium and vanadium from seawater.

• 멤브레인
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• 제12권3호
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• pp.182-191
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• 2002

복합 박막의 구조를 갖는 폴리아미드계 역삼투 분리막은 상용화되어 해수담수화 공정에 널리 적용되어져 왔다. 최근 고압·고회수율 공정은 기존의 해수 담수화 공정에 비해 에너지 비용 및 전처리의 규모의 측면에서 절감 효과를 가진다는 결과들이 발표되어왔다. 고압·고회수율 공정은 에너지 회수, 고압 펌프 설비, 그리고 고압 고염제거율의 역삼투막 개발에 의해 가능해 졌다. 본 연구에서는 기존의 해수담수화 공정에 사용되는 역삼투 분리막에 대한 고압·고회수율 공정 조건에서의 투과 성능을 조사하였다. 역삼투 분리막 평막의 평가에는 3.5%의 NaCl 수용액을 인공해수로 조제하여 실시하였으며 역삼투 분리막 모듈의 평가는 마산시 합포해변에서 자연 해수를 직접 사용하였다. 그 결과로 고압 고회수율 공정에 적합한 역삼투막은 고압에 대한 내압성을 갖는 역삼투막임을 보여준다. 고농축수에 대한 염제거율은 고압 운전에 의해 자연 향상되는 경향을 나타내었다.

• 한국해양환경ㆍ에너지학회지
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• 제18권1호
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• pp.9-14
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• 2015

바닷물 속에는 다양한 종류의 이온들이 존재한다. 바닷물을 음용수로 사용하기 위해서는 특정 성분은 농축하고 또 다른 특정 성분은 제거되어야 한다. 이러한 특성을 갖기 위해서는 바닷물의 수질을 조정하는 것이 필요하다. 특히 2가 양이온인 칼슘과 마그네슘은 인체에 유용한 물질이므로 이를 농축하는 기술이 필요하다. 본 연구에서는 나노막을 거친 농축수를 전기투석 장치를 이용하여 칼슘과 마그네슘을 농축하는 고경도수 제조기술을 연구하였다. 나노막을 이용하여 2가 이온 성분을 농축한 처리수를 얻은 후 이를 전기투석 장치에 적용시켜 1가 이온인 염화나트륨성분을 제거하였다. 이와 같이 전기투석 장치를 이용하여 고경도수를 제조할 수 있었다.

• 분석과학
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• 제33권4호
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• pp.186-196
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• 2020

A simple and rapid preconcentration method of actinide from seawater using Actinide resin was developed and tested with the seawater spiked with a known U and Th. The developed method of Actinide resin based on column chromatography is less time-consuming and requires less labor compared with a typical co-precipitation technique for preconcentration of actinides. U and Th, which are relatively weak-bonded with Actinide resin among actinides, were used to determine the optimum flow rate of seawater sample and evaluate the capacity of Actinide resin to concentrate actinides from seawater. A flow rate of 50 mL min^-1 was available with Actinide resin 2 mL (BV, bed volume). When 5 or 10 L of seawater containing U were loaded on Actinide resin (2 mL, BV) at 50 mL min^-1, the recovery of U was 93 % and 86 %, respectively. For extraction of actinides bound with Actinide resin, we compared three methods: solvent extraction, ashing-acid digestion, and ashing-microwave digestion. Ashing-microwave digestion method shows the best performance of which is the recovery of 100 % for U and 81 % for Th. For the preconcentration of actinides in 200 L of seawater, a typical coprecipitation method requires 2-3 days, but the developed method in this study is achieved the high recovery of actinides within 12 h.

• 상하수도학회지
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• 제31권6호
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• pp.599-609
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• 2017

Desalination plants have been recently constructed in many parts of the world due to water scarcity caused by population growth, industrialization and climate change. Most seawater desalination plants are designed with a submarine pipeline for intake and discharge. Submarine pipelines are installed directly on the bottom of the water body if the bottom is sandy and flat. Intake is located on a low-energy shoreline with minimal exposure to beach erosion, heavy storms, typhoons, tsunamis, or strong underwater currents. Typically, HDPE (High Density Polyethylene) pipes are used in such a configuration. Submarine pipelines cause many problems when they are not properly designed; HDPE pipelines can be floated or exposed to strong currents and wind or tidal action. This study examines the optimal design method for the trench depth of pipeline, analysis of on-bottom stability and dilution of the concentrate based on the desalination plant conducted at the Pacific coast of Peru, Chilca. As a result of this study, the submarine pipeline should be trenched at least below 1.8 m. The same direction of pipeline with the main wind is a key factor to achieve economic stability. The concentrate should be discharged as much as high position to yield high dilution rate.