• Journal of environmental and Sanitary engineering
• /
• v.6 no.2
• /
• pp.33-47
• /
• 1991

1. Water supply treatment plants personnel could not test the water quality control, because most of them rely on the provincial health laboratories about water quality rely rant test. However, in future, plants have to been provided the facilities and equipment of water quality laboratory. 2. Chlorination methods are 89.5% of liquid chlorine and 10.5% of solid chlorine, and the cost per 1 $\m^{3}$ of chlorination is about 1.30 won which chlorination cost is very cheap as 1/142 of drinking water production cost. Input method of chlorine is 35% of automatic method, 56% of semi-automatic, and 9% of other methods, and this is no problem 3. Residual effects of chlorination, in the case of distilled water as a standardized material and 0.2 ppm of seperated residual chlorine, were continued 32 hours in $0^{\circ}C$, and 25 hour in $20^{\circ}C$, of water temperature and in the case of 0.4 ppm of seperated residual chlorine were continued 47 hours in $0^{\circ}C$ and 23 hours in $20^{\circ}C$. 4. In the case of 4 ppm of seperated residual chlorine, residual effects were continued 23 hours in $5^{\circ}C$, 90 hours in $10^{\circ}C$, 78 hours in $15^{\circ}C$, and 60 hours in $20^{\circ}C$ : by the temper; lure of water, continuing residual effects of chlorination are different, so we have to car for the warm season chlorination in the hider temperature. 5. Chlorination effects of drinking waters in the case of 0.4 ppm of seperated residual chlorine were continued 237 hours in $22^{\circ}C$ water : and in the case of rechlorination as 4 ppm of residual chlorine, continued 71 hours in $22^{\circ}C$ water.

• Journal of Environmental Science International
• /
• v.22 no.7
• /
• pp.905-913
• /
• 2013

We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of $H_2O_2/O_3$ ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the $H_2O_2/O_3$ ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process.

• Journal of Korean Society of Water and Wastewater
• /
• v.34 no.1
• /
• pp.35-43
• /
• 2020

Turbidity has various effects on the water quality and ecosystem of a river. High turbidity during floods increases the operation cost of a drinking water supply system. Thus, the management of turbidity is essential for providing safe water to the public. There have been various efforts to estimate turbidity in river systems for proper management and early warning of high turbidity in the water supply process. Advanced data analysis technology using machine learning has been increasingly used in water quality management processes. Artificial neural networks(ANNs) is one of the first algorithms applied, where the overfitting of a model to observed data and vanishing gradient in the backpropagation process limit the wide application of ANNs in practice. In recent years, deep learning, which overcomes the limitations of ANNs, has been applied in water quality management. LSTM(Long-Short Term Memory) is one of novel deep learning algorithms that is widely used in the analysis of time series data. In this study, LSTM is used for the prediction of high turbidity(>30 NTU) in a river from the relationship of turbidity to discharge, which enables early warning of high turbidity in a drinking water supply system. The model showed 0.98, 0.99, 0.98 and 0.99 for precision, recall, F1-score and accuracy respectively, for the prediction of high turbidity in a river with 2 hour frequency data. The sensitivity of the model to the observation intervals of data is also compared with time periods of 2 hour, 8 hour, 1 day and 2 days. The model shows higher precision with shorter observation intervals, which underscores the importance of collecting high frequency data for better management of water resources in the future.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.6
• /
• pp.849-855
• /
• 2006

Taste and odor (T&O) problems in drinking water supplies caused by eutrophication have become increasingly important because aesthetic qualities are the primary measures by which consumers estimate the quality of their drinking water. In order to overcome T&O problem, it is necessary to early detection method for T&O compounds before these compounds enter to water treatment plant. In this background, a early waming device for T&O compounds was developed and its performance tested under different operating condition. According to the experimental results on the adsorption efficiency of T&O compounds, when the raw water flowrate was 5 mL/min, the optimum stripping time and air flowrate were 5 hrs and 0.5 L/min, respectively. Comparison of activated carbon showed that foreign activated carbon was better than domestic activated carbon in terms of adsorption efficiency.

• Journal of Soil and Groundwater Environment
• /
• v.16 no.1
• /
• pp.19-31
• /
• 2011

This study had been carried out to investigate spatial and temporal variations of the concentrations of trace metals for contaminated surface water in creek affected by leachate from the tailings impoundment of the Yeonhwa II mine for about 2 years. It was also to ascertain the metal removal efficiency for potentially deleterious metals by the artificial and natural attenuation processes such as retention ponds and hydrologic mixing of uncontaminated tributaries. The concentrations of As, Pb, Cd, and Cu for leachate in the rainy season were not detected. On the other hand, the concentrations of Zn, Fe, Mn, Al, and $SO_4^{2-}$ in the rainy season for leachate were 2-66 times higher than those in the dry season, due to the oxidation of the sulfide minerals and the dissolution of the secondary minerals. The concentrations of Zn and Cd for leachate and surface water of the upper creek in the rainy season exceeded the criteria of River Water Quality and Drinking Water Quality but in the dry season, those of analyzed all the metals (As, Pb, Cd, Cu, Zn, Cd, Fe, Mn, and Al) for surface water sampled at the study area were below the criteria of River Water Quality and Drinking Water Quality. In regard of the attenuation efficiency for the concentrations of metals, Fe, Mn, Al, Zn, Cd, As, and Cu were removed highly at retention ponds, while the removal efficiency for major cations and sulfate ($SO_4^{2-}$) were related to mixing of the uncontaminated tributaries. Therefore, the major attenuation processes of the metal and sulfate contents in creek affected by leachate from a tailing dump were precipitation (accompanied by metal co-precipitation and sorption), water dilution, and neutralization.

• Journal of Korean Society of Forest Science
• /
• v.87 no.4
• /
• pp.510-518
• /
• 1998

This study was carried out to investigate the drinking patterns of sap water of Acer mono by on-the-spot visitors. The survey was done from late-February to mid-March in the 3 major sap water tapping regions, such as Piagol of Mt. Chiri in Kurey, Okryong of Mt. Baekun in Kwangyang, and Mt. Chokey in Sunchon, Chonnam. A total of 300 visitors over 20 years old, 100 visitors in each region, were interviewed personally to make up questionnaires, irrespective of sex. The purpose of drinking, the frequency of visit, the modes of traffic, the length of stay, drinking amount per person, one's opinions after drinking, drinking plans and patterns, and intention of drinking processed sap were investigated and examined. Wide range of age groups from twenties to sixties drank sap water. Visitors drank sap water in order to keep health, to promote mutual friendship, and so on. 44% of sap drinkers visited for the first time, and 71% visited by private automobiles holding the first place. 59.7% of visitors spent only a day, but 40.3% passed one or two nights to drink sap water. For drinking amount of sap water, $3-6{\ell}$ a was consumed by 31.3% of visitors, under $3{\ell}$ or $9-12{\ell}$ by 22.7% $6-9{\ell}$ by 12.7% and so forth. 74% of visitors felt sap water sweet and favorable, but were doubtful about the efficacy of sap water. 79.0% of visitors had a plan to drink sap water again next year, 40% of whom preferred a day's visit to overnight staying (29%) or 3 days' staying (6%). 45% answered to plan to drink sap water with having meals, and 43% with having meals and passing a night. More than half (54.3%) of the visitors were inclined not to drink processed sap water for the reasons of unreliable quality, unwillingness for process, change in quality, etc.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.2
• /
• pp.155-164
• /
• 2004

Many countries, including Korea, suffer from a shortage of freshwater. With increases in population and the quality of life, along with large-scale expansion in industrial and agricultural activities, more freshwater is needed. Available resources, Including ground water, are limited, and desalination presents the opportunity for a new unlimited source of freshwater from the sea. The objectives of this study were to test membrane performance in seawater desalination and to examine the quality of water produced. bath well and sea water were used as water sources. Typically used membrane for seawater desalination and high rejection seawater desalination membrane are maintained at almost same recovery rate and permeate flux, while the conductivity was lower in the operation of typically used seawater membrane. The treated water quality using two types of membranes is satisfied with the Korea drinking water quality standards.

• Journal of Environmental Health Sciences
• /
• v.27 no.4
• /
• pp.41-46
• /
• 2001

Trihalomethane(THMs) levels in drinking tap water, indoor swimming pool water and industrial effluent in Kunsan area were surveyed in this study. During experimental period, the monthly averages of THMs in drinking tap water from Keumkang wide-area supply ranged from 15$\mu\textrm{g}$/ι/to 50 $\mu\textrm{g}$ showing the highest level in summer. 3 indoor swimming pools showed the monthly average levels of THMs formation ranging from 8$\mu\textrm{g}$/ι/to 20$\mu\textrm{g}$/ι and the pool under public management seemed to maintain its water quality more stable than those under private management THMs concentrations in the effluents. discharged from 10 manufacturing companies, ranged from N.D. to 95$\mu\textrm{g}$/ι and it was estimated that the overall THMs level discharged front those manufacturing companies is not high, reflecting the traces recorded for most effluents. The composition ratios of individual THMs for industrial effluents showed a difference from those for drinking water and swimming pool water, along with their wide variations according to the company and relatively high composition ratios of Br substituents.

• Food Science and Industry
• /
• v.52 no.1
• /
• pp.20-31
• /
• 2019

Sensory perception of food/beverage products is one of the most important quality factors to determine consumer acceptability and thus sensory discrimination methodology has been a vital tool for quality management. Signal detection theory(SDT) and Thurstonian modeling provide the most advanced psychometric approach to modeling various discrimination methods. In these theories, perceptual and cognitive decisional factors are considered so that, a fundamental measure of sensory difference (d') can be computed, independent of test methods used. In this paper, sensory discrimination analysis based on SDT and Thurstonian modeling is introduced for more accurate and systematic applications of sensory and hedonic quality management in industry. Ways to realize the statistical power and relative sensitivity of sensory discrimination methods theorized in SDT and Thurstonian modeling in practice, are also discussed by using a case study of the Nongshim quality management program for drinking water in which SDT A-Not A test methodology was further optimized.

• Journal of Environmental Health Sciences
• /
• v.4 no.1
• /
• pp.41-46
• /
• 1977

Main objectives of this survey were to find out general sanitary status of water source, draining status and toilet in Shindong Myun, Chungseong Gun. Interviewers of fourteen students visited 1,775 households in this Myun, filled the survey form and checked sanitary conditions of the areas from September 1 to November 30, 1974. Results are summarized as follows: 1. Draining state of pumps is better than that of wells and also the the quality of water sources are better in pumps than in wells. Wells and pumps of 54.1% were constructed more than five years ago. 2. About 66.7% use pump water, 10.5% well water and 8.3% simple piped drinking water system and average water consumption is 22.7l per day per capita. Private water system is 66.0% while public system 27.1%. 3. Water is used for drinking, washing body and cleaning at 53.8% while only for drinking at 7.4%. 4. Nearest pollution sources of drinking water are mainly toilets and stables, and average distances between them are less than ten meters. 5. Toilets of 78.3% are used only by one households and those of 12.9% by two. 6. Toilets of 10.9% are inside main building while those of 85.4% outside main building. 7. Toilet tanks are covered only at 6.3% households while not covered at 95.4%. The contents of tanks are removed about twice a month (40.2%), and 84.1% use them as fertilizer on their own farm and contents of 10.1% are removed by other people. 8. Excreta are utilized on the vegetable farm by 38.2% households, on the vegetable and barley farms by 19.7% and on the paddy fields by 8.2%.