• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.453-460
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• 2018

The impact of sodium hydroxide, which is one of chemicals of clean in place (CIP) for removing membrane fouling, on the PVDF membrane is reviewed with respect to physical/chemical structural change, the permeability affected therefrom. Based on the cleaning concentration applied in membrane water treatment facilities, 10% of accumulated defluorination was confirmed up to 166g.hr/L which reflects the exposure time. However, membrane resistance was confirmed to be reduced by about 10%. Through FT-IR and EDS analysis, reduction of F and change of are confirmed as factors that affect the permeability of membrane. Membrane resistance, which affects permeability, is affected by loss of additives for hydrophilicity, rather than defluorination of PVDF material. Therefore, in order to check membrane degradation degree, an accelerated test by NaOH was carried out, loss of additives was confirmed, and then PVDF inherent characteristic was observed.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.22-33
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• 1996

With the experience of the 1994 drought, and the shortage of water resources in Japan, it has been re-informed upon us ensure and maintain the stability of water resources. Accordingly, with each plant, a serious appraisal has begun looking at the re-use of waste water. Membrane technology is an important process for waste water recovery. Effluent kom waste water facilities changes the quality of water significantly. The conventional pre-treatment of RO is hard to supply good quality feed water to RO in the waste water recovery system. The microfiltration system as a pre-treatment of RO in the paper overcomes the fouling with the air backwash and is operated in direct flow mode at a low pressure producing a high flux. The paper will focus the waste water recovery using membrane technology and many examples will be given.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.261-265
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• 2008

To solve the lack of housing, our country has supplied an enormous volume of apartments, and these days it occupies 75% of our buildings. As apartments occupy most of our housings, the rate of energy usage from them are also high. On this, setting apartment energy reduction as a target, by researching the actual conditions of energy consumption and drawing a basis data, we can apply this as a way of saving energy, rationalization of the scale of energy supply facilities and a standard when planning facilities. To grasp the present condition of energy usage of the urban rental apartment, this research analysed the use of electricity, gas and water monthly and annually of a rental apartment that is located in Daegu. The results showed that in 2003 the electricity usage was 1,198MWh but 1,315MWh in 2007, which means 9% of electricity usage increases every year. The average of water usage was $85,072m^2$ per year and they used $604.2MJ/m^2$ Typical energy consumption unit on $74.4m^2$ of area and $448.8MJ/m^2$ on $105.8m^2$. By showing the usage of energy and water of the urban rental apartment, understanding the tendency and preparing an Typical energy consumption unit standard through this research, apartments should use energy more efficiently.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.33-42
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• 2018

This study evaluated the vulnerability of irrigation water supplied to the crops. The target areas were selected as Dangjin-si, Yesan-gun, and Cheongyang-gun. The survey items of the climate exposure were annual precipitation and rainless days. The sensitivity survey items were cultivation area, groundwater level, evapotranspiration and groundwater consumption. The survey items of the adaptability were Number of groundwater well and Water supply ratio. The survey methods for these items were investigated in a variety of ways, including "National Climate Data Service System", "Korean Statistical Information Service", "National ground water monitoring network in korea annual report" and "Chungcheongnam-do Statistical Yearbook", "HOMWRS". Vulnerability assessment results were rated within the range of 0~100 points. The first grade was rated 0-25, the second grade 26-50, the third grade 51-75, and the fourth grade 76-100. And the lower the score, the lower the vulnerability. As a result, Cheongyang-gun showed a high vulnerability of over 50 points, Dangjin-si showed a low vulnerability rating of 31.20 points and a Yesan-gun of 36.00 points.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.145-151
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• 2008

A novel method was suggested for the estimation of design population and design wastewater flow rate in fishing and agrarian village. Even though the population was decreasing continuously in this area, the design population was considered as constant with the passage of the time in conventional methods. And although the portion of groundwater uses was pretty high, the design wastewater flow rate was determined by the supply amount of tap water. Consequently, the design population and the design wastewater flow rate were overestimated. To prevent these overestimates, the design population was predicted to decrease gradually using the population trends from Korea National Statistical Office, and the design wastewater flow rate was determined using the way that the supply amount of tap water was applied in developed areas and the supply amount of groundwater was used in undeveloped areas.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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• pp.651-657
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• 2015

Recently, the need for asset management(AM) plan introduction to reduce increasing O&M cost with aging water facilities is on the rise. Therefore, asset inventory classification is necessary as the first step for AM plan construction. In this study, all assets of YW water treatment plant(WTP) were classified as 5 steps. In addition, specific code name was given to each asset which can increase compatibility in constructing the AM programs among WTPs. In the future, codes for attribute and status of asset will be allocated, which can facilitate proper AM operation.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.4
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• pp.43-52
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• 1998

The purpose of this study is to establish a method of estimating the daily urban water demend using Backpropagation algorithm is part of ANN(Artificial Neural Network). This method will be used for the development of the efficient management and operations of the water supply facilities. The data used were the daily urban water demend, the population and weather conditions such as treperarture, precipitation, relative humidity, etc. Kwangju city was selected for the case study area. We adjusted the weights of ANN that are iterated the training data patterns. We normalized the non-stationary time series data [-1,+1] to fast converge, and choose the input patterns by statistical methods. We separated the training and checking patterns form input date patterns. The performance of ANN is compared with multiple-regression method. We discussed the representation ability the model building process and the applicability of ANN approach for the daily water demand. ANN provided the reasonable results for time series forecasting.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.37-50
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• 2019

It is possible that radon removal in groundwater of small-scale water supply system (SWSS) is caused by atmospheric storage and aeration facilities installed in the water tank. Radon removal rates at water tank and tap of the 32 SWSS during summer season ranged from -69.3% to 62.7% (average 25.7%) and from -64.3% to 83.1% (average 30.3%) while those of 16 SWSS during autumn season ranged from 21.3% to 78.0% (average 42.8%) and from 17.7% to 66.9% (average 44.8%). The reason of higher radon removal rate in the autumn season compared with the summer season is due to higher atmospheric storage effect by lower groundwater use rate. The radon removal rates at the water tank from 12 SWSS were 47.4~94.0% (average 78.9%), in which the removal rates at the atmospheric storage are also included. Atmospheric storage and aeration can be used to reduce radon concentration in SWSS groundwater. For more efficient use of radon reduction, further studies are necessary to assess the radon removal rate considering variation conditions of radon concentration in groundwater, size and forms of water tank, change in groundwater usage rate, aeration capacity and ventilation facilities.

• Journal of Korean Society of Rural Planning
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• v.26 no.3
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• pp.39-47
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• 2020

While agricultural water has been declared free in Korea to ensure access to these limited resource since the year 2000, farmers have however developed lackadaisical behavior towards water saving leading to its scarcity. To overcome this problem, a variety of experience-oriented education model was developed for farmers to promote the adoption of water conservation, and preventive measure against the drought impacts. In this study, farmers' awareness and their attitudinal behavior of agricultural water savings were investigated. The monitoring of water supply structure and the repair facilities in Pohang and Yeongdeok areas were conducted. The field visits and behavioral surveys showed a high degree of over-use and illegal water withdrawals by the farmers due to poor water-saving and management practices. We found that most of the KRC employees strongly admitted the necessity of water-saving education. On the other hand, the farmers showed good interest in the implementation of water-saving awareness through education. Besides this, most farmers agreed to adopt water-saving practices in the fields. Farmers also acknowledged the recklessness of water use was due to the aging of waterways, poor water management, and illegal water consumption. The majority of the farmers responded against imposing the water-use tariffs. However, there was a low response to paying the water-use charge. Aging agricultural facilities and the lack of institutional penalties or incentives were the major obstacles in achieving efficient water-saving. Considering the current drought frequency, urgent water-saving education of farmers was deemed necessary to prepare the farming community against the water shortages. Based on the results of this study, we have to identify the irrigation practices of farmers and provide water-saving education to enforce more efficient use and management of agricultural water.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.1-8
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• 2018

In Korea, water supply capacity and facility investments had been emphasized around the 1980s. The water pricing have gained focuses in water policy since the 1990s. This study analyzes a water demand and estimates the relation of water demand and other socio-economic variable, using econometric models on the city of Busan. Water price and income are two key elements to explain water demand. Modeling approach using translog function provides better results, and water demand responds positively to population and income. Energy and water prices are negative factors in deciding water demand. It is requested that water pricing needs to reflect more production costs. Alternative approaches such as water saving facilities by household and use of digital water information should be emphasized for efficient water management in a local community.