• 상하수도학회지
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• 제29권1호
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• pp.89-96
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• 2015

Smart water grid is a water network with communication to save water and energy using various water resources. In smart water grid, water product from the various sources can be blended to be supplied to end-users. The product water blending was reported by literatures while feed water blending has been rarely reported so far. In this work, a commercial reverse osmosis (RO) system design software provided by a membrane manufacturer was used to elucidate the effect of feed water blending on the performance of seawater reverse osmosis (SWRO) plant. Fresh water from exisiting water resource was assumed to be blended to seawater to decrease salt concentration of the RO feed water. The feed water blending can simplify the RO system from double to single pass and decrease seawater intake amount, the unit prices of the RO system components including high pressure pump, and operation risk. Due to the increase in RO plant capacity with the feed water blending, however, the RO membrane area and total power consumption increase at higher water blending rates. Therefore, a specific benefit-cost analysis should be carried out to apply the feed water blending to SWRO plants.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.153-164
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• 2005

The paper presents time and cost effective remote sensing technology to estimate recharge potential of fresh water shallow aquifers for their sustainable management in arid ecosystem. Precipitation measurement of Raudatain Basin in Kuwait from TRMM data has been made and integrated with geological, geomorphological and hyrological data, to estimate the recharge potential of the basin. The total potential recharge to the area is estimated as 333.964 MCM annually. The initial losses are estimated at $60\%$ of the net precipitation .The net available quantity for recharge is 133.58 MCM. For sustainable management of the ground water resources, recharge wells have been proposed in the higher order streams to augment the Raudatain aquifer in Kuwait. If the available quantity of precipitation can be successfully utilized, it will reduce considerable pressure on desalination, which is leading to increased salinity off the coast in Arabian Gulf.

• 한국표면공학회지
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• 제54권2호
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• pp.90-95
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• 2021

Surface modification technique enabling the control of condensation provides various benefit in various engineering systems, such as heat transfer, desalination, power plants, and so on. In this study, lubricant oil-impregnation into Teflon-coated nanoporous anodic oxide layer of aluminum to enhance a de-wetting and mobility of water droplet on surface. Due to the surface treatment improving water-repellency, the condensation mode is changed to dropwise, thus the frequency of sliding condensed water droplet on surface is increased. For these reasons, the surface of oil-impregnated Teflon-coated nanoporous anodic aluminum oxide shows significantly enhanced condensation heat transfer compared to bare aluminum surface. In addition, the porosity of anodic aluminum oxide affected the mobility of water droplet even with oil-impregnation and Teflon-coating, indicating that the optimization of porous structure of anodic oxide is required for maximizing the condensation heat transfer.

• 농업생명과학연구
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• 제46권2호
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• pp.169-178
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• 2012

새만금 지역의 담수수자원의 활용과 고부가가치 창출을 위해 새만금 담수호를 활용한 요구수질별 용수공급을 위한 최적의 수처리 시스템을 선정하고 이에 대한 비용분석을 통해 요구수질별 담수수자원의 활용방안을 제시하고자 하였다. 다양한 수처리 기법들의 종류, 주요 특성 및 오염인자 제거효율, 공법의 장단점 등의 비교분석을 통해 수질오염인자별 유리한 처리공법을 제시하였으며, 최적의 수처리시스템을 도출하여 새만금 지역 내 요구수질별 수처리 비용을 분석하였다. 연구결과를 통해 SS(Suspended Solid), BOD(Biochemical Oxygen Demand), 탁도 제거를 위해 FDA(Filter Disinfection Adsorption)여과기, 대장균 제거를 위한 UV(Ultra-Violet)처리공정, T-P(Total Phosphorus), T-N(Total Nitrogen) 제거를 위한 FNR(Ferrous Nutrient Removal)공법, 그리고 저농도 염처리 공정을 위해 전기투석법이 유리한 공법으로 조사되어 최적의 수처리시스템의 요소기술로 각각 선정되었다. 각 요구수질별 선정된 수처리공정에 따른 비용분석과 적용사례를 제시하여 새만금지역 담수 활용도를 높이고 부족한 상수원 해결의 대안으로 적용할 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1114-1119
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• 2004

The biofilms on pipe walls in water distribution systems are of interest since they can lead to chlorine demand, coliform growth, pipe corrosion, and water taste and odor problems. As such, the study described in this paper is part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different source waters on the water quality in various distribution systems. The project was based on 18 independent pilot distribution systems (PDS), each being fed by a different water blend (7 finished waters blended in different proportions). The source waters compared were groundwater, surface water, and brackish water, which were treated in a variety of pilot distribution systems, including reverse osmosis (RO) (desalination), both membrane and chemical softening, and ozonation-biological activated carbon (BAC), resulting in a total of 7 different finished waters. The observations from this study consistently demonstrated that unlined ductile iron was more heavily colonized by a biomass than galvanized steel, lined ductile iron, and PVC (in that order) and that the fixed biomass accumulation was more influenced by the nature of the supporting material than by the water quality (including the secondary residual levels). However, although the bulk liquid water cultivable bacterial counts (i.e. heterotrophic plate counts or HPCs) did not increase with a greater biofilm accumulation, the results also suggested that high HPCs corresponded to a low disinfectant residual more than a high biofilm inventory. Furthermore, temperature was found to affect the biofilms, plus the AOC was important when the residual was between 0.6 and 2.0 mg $Cl_2/l$. An additional aspect of the current study was that the potential of the exoproteolytic activity (PEPA) technique was used along with a traditional so-called destructive technique in which the biofilm was scrapped off the coupon surface, resuspended, and cultivated on an R2A agar. Both techniques indicated similar trends and relative comparisons among the PDSs, yet the culturable biofilm values for the traditional method were several orders of magnitude lower than the PEPA values.

• 한국토양비료학회지
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• 제45권5호
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• pp.717-724
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• 2012

Salt accumulated soil should be reclaimed to lower salt level for crop production. This study was carried out to investigate the characteristics of water flow and transport of mono and divalent solutes on salt accumulated soils with different head pressures. Saturated hydraulic conductivity was measured by constant and falling head methods with maintaining different head pressures. Saturated hydraulic conductivity was influenced by bulk density and organic matter contents in soils, but it had different elusion patterns between saline and sodic soil. While the quantity of water necessary for reclamation could be varies with soil type, it was considered that the supply of one pore volume of water was affordable and economic. Additional head pressure significantly increased the volume of leachate at a given time and it was more effective at low organic matter soils. The results indicate that additional head pressure would be one of the best irrigation practices on desalination method for salt accumulated soils.

• 한국해양공학회지
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• 제13권3B호
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• pp.3-13
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• 1999

The diffusion characteristics of the high temperature and salinity water discharged in Chinhae Bay under BMP(Barge-Mounted Plants) desalination processes were simulated to access environmental impact. The 3-D baroclinic flow model is formulated by integrating the basic equations with respect to each control volume and by transforming them into a finite difference form using the space-staggered grid system. With a 3-D baroclinic flow model, the tide-induced and density-induced current was computed and confirmed by comparing with observed data. From the results of numerical experiment, it is expected that the maximum diffusion lengths of the high temperature and salinity which increase $0.6^{circ}C$ and 0.2 after discharging are 1 km and 3.5km, respectively. It may be expected that the discharge has an effect on surrounding area of discharge, but not an effect on whole area of Chinhae Bay.

• Membrane and Water Treatment
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• 제8권5호
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• pp.411-421
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• 2017

Forward osmosis (FO) is an emerging technology which can possibly make the desalination process more cost and energy efficient. One of the major factors impeding its growth is the lack of an appropriate draw solute. The present study deals with the identification of potential draw solutes, and rank them. The comparison was carried out among ten draw solutes on the basis of four main parameters namely; water flux, reverse salt diffusion, flux recovery and cost. Each draw solute was given three 24 hour runs; corresponding to three different concentrations; and their flux and reverse salt diffusion values were calculated. A fresh membrane was used every time except for the fourth time which was the flux recovery experiment conducted for the lowest concentration and the change of flux and reverse salt diffusion values from the initial run was noted. The organic solutes inspected were urea and tartaric acid which showed appreciable values in other parameters viz. reverse salt diffusion, flux recovery and cost although they generated a lower flux. They ranked 5th and 8th respectively. All the experimented draw solutes were ranked based on their values corresponding to each of the four main parameters chosen for comparison and Ammonium sulfate was found to be the best draw solute.

• 상하수도학회지
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• 제30권3호
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• pp.343-350
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• 2016

Membrane distillation (MD) is a novel separation process that have drawn attention as an affordable alternative to conventional desalination processes. However, membrane fouling and pore wetting are issues to be addressed prior to widespread application of MD. In this study, the influence of ultrasonic irradiation on fouling and wetting of MD membranes was investigated for better understanding of the MD process. Experiments were carried out using a direct contact membrane distillation apparatus Colloidal silica was used as a model foulants in a synthetic seawater (35,000 mg/L NaCl solution). A vibrator was directed attached to membrane module to generate ultrasonic waves from 25 kHz (the highest energy) to 75 kHz (the lowest energy). Flux and TDS for the distillate water were continuously monitored. Results suggested that ultrasonic irradiation is effective to retard flux decline due to fouling only in the early stage of the MD operation. Moreover, wetting occurred by a long-term application of ultrasonic rradiation at 75 kHz. These results suggest that the conditions for ultrasonic irradiation should be carefully optimized to maximize fouling control and minimize pore wetting.

• 상하수도학회지
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• 제33권6호
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• pp.413-420
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• 2019

Pretreatment system of desalination process using seawater reverse osmosis(SWRO) membrane is the most critical step in order to prevent membrane fouling. One of the methods is coagulation-UF membrane process. Coagulation-UF membrane systems have been shown to be very efficient in removing turbidity and non-soluble and colloidal organics contained in the source water for SWRO pretreatment. Ferric salt coagulants are commonly applied in coagulation-UF process for pretreatment of SWRO process. But aluminum salts have not been applied in coagulation-UF pretreatment of SWRO process due to the SWRO membrane fouling by residual aluminum. This study was carried out to see the effect of residual matal salt on SWRO membrane followed by coagulation-UF pretreatment process. Experimental results showed that increased residual aluminum salts by coagulation-UF pretreatment process by using alum lead to the decreased SWRO membrane salt rejection and flux. As the salt rejection and flux of SWRO membrane decreased, the concentration of silica and residual aluminum decreased. However, when adjusting coagulation pH for coagulation-UF pretreatment process, the residual aluminum salt concentration was decreased and SWRO membrane flux was increased.