• Journal of environmental and Sanitary engineering
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• v.16 no.1
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• pp.27-33
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• 2001

The purpose of this study on environmental investigation in Hongsung and Kwangchun streams is for the finding the degree of water quality. Physicochemical characteristics of streams are very important. However, that has not been investigated so for especially in stream of Hongsung area, And so, we tried to analyse BOD, TDS, $Cl^{-}$, anionic surfactant, pH, T-N and T-P of stream. The results were as follows. The pH for stream were generally in the range of 6.9 ~ 8.1 which is water quality for stander for stream, water quality of the Hongsung and Kwangchun upstream was not in problem but downstream showed somewhat high concentration in BOD, chlorine ion, T-P, T-N, and anionic surfactants. Especially BOD of Kwangchun downstream was higher than Hongsung downstream and concentration of T-P of Hongsung downstream was kept over 7 mg/liter regardless of inflow BOD ranging from 1.3 to 1.8 mg/liter.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.1015-1024
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• 2020

Recently, water pollution accidents have continued to occur in pipelines such as red water Incheon and Seoul. In order to recognize this water quality problem, it is necessary to install a water quality sensor in an appropriate location and measure it in advance to detect or block the water supply to the water faucet of the shelter. However, there are limitations, such as maintenance costs, to installing multiple water meters in all pipelines. Therefore, this study proposed a methodology for determining and prioritizing the installation location of flow-based water quality sensor for the recognition of water quality problems in pipelines. We applied the proposed procedure to the pipe break scenario. The results of the determination of the location of the water quality sensor were presented by applying it to the pipe network that actually operates the emergency pipe in Korea. The result of the decision showed that in the event of abnormal situation caused by the destruction of individual pipes, the flow rate of the pipes around the aqueduct and the tank may change rapidly, resulting in water quality accidents caused by turbidity. In the future, it is expected that the water quality monitoring point selection method, such as establishing an external pipe operation plan for pipe cleaning, will utilize the procedure for determining the location of the water quality sensor according to the velocity.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.538-547
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• 2017

Korea's water management system is typically a multi-ministerial system, so its efficiency is declining. In order to propose current state and improvement plan of the water management in Korea, this study discussed the improvement of central and local water management. The water management problems are lack of water policy coordination system, conflicts between ministries due to function of water quantity, water quality and agricultural water, redundant investment and inefficiency, insufficient recognition of water autonomy, concentrated central management and deepening regional disparities, lack of financial resources, etc. Hence, improvement to solve the problem includes strengthening the coordination of water management functions between ministries, transferring water management functions of central ministries and strengthening local capacity, and desirable role allocation of central and local governments. In addition, improvement at the local include efforts to change awareness of the water detailed and get water autonomy, integrate management of the watershed, strengthen the local community, secure financial resources, etc.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.36-41
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• 2008

Cooling tower is an important equipment of the cooling systems for large buildings like factory and department store. Water used for cooling in cooling tower is reused continuously. If the water is polluted, corrosion and scale can happen at equipments and pipes. In order to prevent this problem, it is necessary to control the water quality using chemicals. To control the water quality, an automatic control system is designed, fabricated, and experimented. The control system is based on an imbedded microcontroller. Relays are used for power driving, an LCD and LED for display, and RS485 for remote data acquisition. Monitoring program is also developed for easy man-machine interface and extraction of data stored in the imbedded processor and EEPROM. The control system calculates amounts of chemicals necessary using sensor data and injects the chemicals into the cooling tower on proper time. The developed water quality control system is expected to reduce cost of maintenance and extend the lifetime of the cooling systems with low cost.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.712-720
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• 2016

When bioethanol and water are mixed at a proper ratio, phase separation can occur because of the immiscibility of biobutanol with water. Phase separation in bioethanol blends fuels is a major problem for gasoline vehicle users due to effect of octane number and component corrosion. Thus, in this study, the phase separation of bioethanol was examined effect of bioethanol blends (E3 (3 vo.% bioethanol in gasoline), E5 and E10) in presence of water. The effect were evaluated behavior with phase separation test, simulation test of fuel tank in gas station according to water addition volume and it was investigated change of water content, bioethanol content and octane number for gasoline phase in bioethanol blends (E3, E5 and E10) every 1 week after water addition. The E3 occurred phase separation more easily than the E5 and E10 in small water contents because solubility of water on ethanol content difference in gasoline-ethanol. It was kept a initial level of water content, bioethanol content, and octane number by repeated sample replacing in simulation test of fuel tank.

• Tribology and Lubricants
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• v.36 no.6
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• pp.385-390
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• 2020

It rains heavily, such as long rain and typhoons, during a typical rainy season in Korea. In this season, several fuel contamination accidents by water and vehicular problems caused by water contaminated fuel occur. Many research groups have studied the effects of water contaminated fuel on vehicles and environment. However the characteristics of water contaminated fuel have not been studied. In this study, we prepared diesel samples with a constant ratio of water (0~30 volume %) using an emulsifier. Then, we analyzed these diesel samples for their representative fuel properties. In the analytical results, diesel with 30% water showed an increase in fuel properties such as density (823→883 kg/㎥), kinematic viscosity (2.601→6.345 ㎟/s), flash point (47→56℃), pour point (-22→2℃), CFPP (cold filter plugging point) (-17→20℃) and copper corrosion number (1a→2a). The low temperature characteristics, such as low pour point and CFPP, blocks the fuel filter in the cold season. In addition, water contaminated diesel decreases lubricity (190→410 ㎛) under high frequency reciprocating rig (HFRR) and derived cetane number (54.81→34.25). The low lubricity of fuel causes vehicle problem such as pump and injector damage owing to severe friction. In addition, the low cetane diesel fuel increases exhaust gases such as NOx and particulate matters (PM) owing to incomplete combustion. This study can be used to identify the problems caused by water contamination to vehicle and fuel facilities.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1151-1160
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• 2009

Perfluorinated compounds (PFCs) have been recognized as emerging environmental pollutants and are widely distributed all over the world. These compounds are hardly degradable and cause bioaccumulation and biomagnification during present for a long time in the environment: thereby after adversely biota and human bodies. It is difficult to remove PFCs using conventional water/wastewater treatment because of resistant property to photodecomposition, biodegradation and chemical decomposition. Moreover, domestic literature data on the pollution of PFCs in rivers and lakes are limited. In this paper, species, sources and risk of PFCs as well as behavior properties in drinking water/wastewater and treatment processes are demonstrated to encourage the domestic concern about PFCs.

• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.875-901
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• 2008

This article estimates the economic values of changes in water quality of the Paldang Watershed by using the Choice Experiment (CE). The conditional logit model estimation results show that a small improvement in water quality from the 'status quo' level to the level of 'very good' increases average household's monthly utility by 3,157 Won, whereas a water quality degradation down to the 'normal' level gives rise to an increase in the monthly average utility by 9,649 Won. The corresponding social gain and loss of water quality changes to the Metropolitan Area were thus estimated about 285 billion Won and 872 billion Won, respectively. This article seems meaningful in that it resorts to the new water ecosystem classification criteria and indices that are respondent-friendly. They help a CE study like this to overcome one of its critical weakness that the number and contents of attributes of a CE study can quickly add to the information overload problem, especially where the environmental good under investigation is hard for ordinary respondents to understand.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.503-508
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• 2007

Small scale D-water treatment plant(WTP) where has slow sand filtration was using raw water containing high concentration of manganese (> 2mg/l). The raw water was pre-chlorinated for oxidation of manganese and resulted in difficulty for filtration. Thus, sometimes manganese concentration and turbidity were over the water quality standard. Two stage rapid manganese sand filtration pilot plant which can treat $200m^3/d$ was operated to solve manganese problem in D-WTP. The removal rate of manganese and turbidity were about 38% and 84%, respectively without pH control of raw water. However, when pH of raw water was controlled to average 7.9 with NaOH solution, the removal rate of manganese and turbidity increased to 95.0% and 95.5%, respectively and the water quality of filtrate satisfied the water quality standard. Manganese content in sand was over 0.3mg/g which is Japan Water Association Guideline. The content in upper filter was 5~10 times more than that of middle and lower during an early operation but the content in middle and lower filter was increased more and more with increase of operation time. This result means that the oxidized manganese was adsorbed well in sand. Rapid manganese sand filter was backwashed periodically. The water quality of backwash wastewater was improved by sedimentation. Thus, turbidity and manganese concentration decreased from 29.4NTU to 3.09NTU and from 1.7mg/L to 0.26mg/L, respectively for one day. In Jar test of backwash wastewater with PAC(Poly-aluminum chloride), optimum dosage was 30mg/L. Because the turbidity of filtrate was high as 0.76NTU for early 5 minute after backwash, filter-to-waste should be used after backwash to prevent poor quality water.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.39-51
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• 1992

This study was carried out for 1 year between 1990 and 1991. The interviewers visited 513 households to evaluate the perception of the residents using the Simple Piped Water Supply (SPWS), and examined the pollution source surrounding 48 SPWS facilities and water quality by the chemical and microbiological method. The purpose of this study was to find out problems linked with SPWS and to investigate more efficient way of improvement in rural water supply. The results of the study are summarized as follows: 1) Approximately 44.0% of the sampled population have been served by simple piped water supply. 2) The drinking water was mostly taken from the springs in 8 sites and valley water in 40 sites. 3) Considering the type of distribution of the SPWS, there are 40 natural gravity systems and 8 pumping systems. 4) Out of the 180 SPWS in Chun Sung Area, 73.9% of the SPWS facilities %'ere used more than ten years. 5) 47.4% of the SPWS facilities are neighbored with pollution source. 6) 42.4% of the maintenance crews were not committed to their job but instead, the facilities were operated by some residents or community leaders who were personally concerned about quality of the facilities. 7) About 36.9% of the residents complaind that the amount of daily water supply is not adequate. 8) About 55.6% of the residents felt that the water quality is good for drinking water and therefore, But in contrast, the biochemical tests indicated that most of the SPWS met the drinking water quality standards. 9) Under the present water analysis system, The method of sampling and analysis are not effective, so that analysis system shoud be done by local health center.