• Journal of environmental and Sanitary engineering
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• v.10 no.1
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• pp.106-125
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• 1995

Recently, in accordance with elevation of life style and economics, the public demand became increasingly concerned about drinking water quality. Without an adequate supply of safe water, healthy and comfortable life could not exist. Therefore, the purpose of this study is to provide the guidelines and the basic informations to enable supply of clean, tasty and healthy drinking water acceptable for various demands. We analyzed the quality of tap water, mineral water, purified tap water using home tap water purifier. And we researched on the sense of the public complaint over the tap water. We proposed several items relating to the comfortableness of water quality and the target value. Also we presented a case of water supply system for purity and the points at problem The items and target value are as follows 1. turbidity : not more than 1 degree 2. dry residue : $30~200{\;}mg/{\ell}$ 3. hardness : $10~100mg/{\ell}$ 4. free carbon dioxide : not more than $20mg/{\ell}$ 5. $KMnO_{4}$ consumption not more than $3mg/{\ell}$ 6. odor threshold not abnormal 7. residual chlorine : not more than $0.4mg/{\ell}$ 8. water temperature' not more than $20^{\circ}C$ 9. manganese : not more than $0.01mg/{\ell}$ 10. iron : not more than $0.02mg/{\ell}$ 11. aluminum : not more than $0.1mg/{\ell}$

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.668-671
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• 2013

This paper describes activated carbon block filters prepared by extrusion for water purifier. The specific surface area of the activated carbon blocks affecting the properties of a polymer binder were investigated. Polyethylene (PE) particles were used as a binder polymer and the effect of particle sizes on changes in the specific surface area of activated carbon blocks in addition to the adsorption properties of chloride anion in the aqueous solution were investigated. The sizes and shapes of PE particles were measured using SEM. The specific surface area of activated carbon was $1186m^2/g$. The specific surface area of PE binder was $444m^2/g$ and $940m^2/g$ with the particle sizes of $200{\mu}m$ and $20{\mu}m$, respectively. In order to verify the performance of the filter, chlorine adsorption experiments were conducted.

• Membrane and Water Treatment
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• v.13 no.5
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• pp.227-233
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• 2022

The objective of the study, to develop adsorbent based purifier for removal of radiological and nuclear contaminants from contaminated water. In this regard, 3-aminopropyl silica functionalized with ethylenediamine tetraacetic acid (APS-EDTA) adsorbent prepared and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Prepared APS-EDTA used for adsorptive studies of Cs(I), Co(II), Sr(II), Ni(II) and Cd(II) from contaminated water. The effect on adsorption of various parameters viz. contact time, initial concentration of metal ions and pH were also analyzed. The batch method has been employed using metal ions in solution from 1000-10000 ㎍/L, contact time 5-60 min., pH 4-10 and material quantities 50-200 mg at room temperature. The obtained adsorption data were used for drawing Freundlich and Langmuir isotherms model and both models were found suitable for explaining the metal ions adsorption on APS-EDTA. The adsorption data were followed pseudo second order reaction kinetics. The maximum adsorption capacity obtained 1.3037-1.4974 mg/g for above said metal ions. The results show that APS-EDTA have great potential to remove Cd(II), Co(II), Cs(I), Ni(II) and Sr(II) from aqueous solutions through chemisorption and physio-sorption.

• Membrane Journal
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• v.8 no.4
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• pp.220-227
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• 1998

Recent data from Environmental department show that some out of 2,000 places surveyed are contaminated by nitrate, ammonia, fluoride, chloride and so forth in excess of the environmental standard-including purification plants, water taps, small water supply systems. In this study, some items which exceed drinking water standard were chosen and their concentrations were made varying from around standard level to around detected maximum concentration. After they permeated through the membrane module sold in the domestic market and made for household water-purifier, the most suitable membranes were selected according to individual water quality of various regions. In addition, the bacterial growth after storage for various days and under various temperatures was examined for the purpose of the effect of the time and temperature on bacterial growth.

• Tribology and Lubricants
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• v.11 no.1
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• pp.58-65
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• 1995

When marine lubricating oil began to be emulsified and oxidized through ingressive water that have leaked from cooling pump seal systems, cooler, purifier system and piping system, the cavitation erosion-corrosion in alloy metals of bearings remains to the various troublesome problem at effective engine performance. Therefore, applied the cathodic protection to the control test of cavitation erosion-corrosion, and appointed the marine system oil containing 3% sea water as test environments, with different conductibility. Also, used the piezoelectric vibrator with 20 KHz, 24 $\mu$m as the cavity generation apparatus, and examined the weight loss, potential value, current density etc. in specimens with those condition. According to this testing data, investigated influence of cathodic protection on the control characteristics of cavitation erosion-corrosion, and will serve those as an elementary design data of marine bearing.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.88-94
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• 2021

Machining operations require the removal of chips to keep the water-soluble cutting oil clean and fresh throughout the operation time. Water-soluble cutting oil for metal processing is diluted using a 3-8% solution in water which is generally replaced every three to six months. This study aims to develop multiple purification devices to efficiently remove fine contaminating particles from water-soluble cutting oil. The 2D concept designs were created using AutoCAD. The designs were drawn using the 3D modelling feature of CATIA. Flow analysis was performed in a bubble purifier using Ansys computational fluid dynamics (CFD). This analysis has aided in improving the design and structure of the device to create the final prototype. Experiments were conducted to check the prototype's performance. Comparisons of the effects of each process variable on the experiment was carried out using ANOVA.

• Design & Manufacturing
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• v.15 no.3
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• pp.13-18
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• 2021

In plate forming technology, cylindrical drawing process is widely used in industry due to technological development. In this study, we used stainless steel 3042B and stainless steel 304J1, which are the most commonly used materials in the production of cold and hot water tanks for water purifiers, among cylindrical drawing products. Under the same conditions, the thickness of the sidewall of the product formed by drawn experiment was studied. As a result of the experiment, the bottom thickness of stainless steel 304J1 was considered to be thick. It is judged that the defect rate can be reduced by changing the breaking phenomenon of the floor surface of the cold and hot water bottles to the material of stainless steel 304j1. Stainless steel 304 2B material shows a sharp change in thickness from punch corner R to sidewall position, while stainless steel 304J1 material showed a uniform change from punch corner R to sidewall position. Stainless steel 304J1 material is considered to improve the clamping of the product in the process of extracting the product after hand drawing. The appearance of stainless steel 3042B products is considered to produce more wrinkles in the flange, which exerts greater tensile force on the sidewall during molding, resulting in uneven sidewall thickness.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.5
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• pp.59-66
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• 2017

Preeminent water treatment plans are essential to preserve the water quality of aquatic biotopes. Previous studies have not been sufficient to provide cost-effective maintenance method since they focused only on the purification of deteriorated water that requires a continuous supply of clean water. This study proposes an economical method of water quality maintenance using water treatment media block constructed vertically using porous ceramics, zeolite, and river pebble. The water treatment media block does not require a separate purification area because it functions as a purifier within the ecological pond which can maximize the biotope area. To evaluate the performance of the water treatment media block, we longitudinally tracked the change of water quality indicators (pH, TDS, COND, DO, T-P, T-N, COD) suggested by Water Environment Standards, Ministry of Environment, Republic of Korea. We compared the water quality of one control (A: general ecological pond composition method of the laminated structure) and two experimental groups (B: a combination of aquatic plants and a water treatment media block, C: a water treatment media block only). As a result, we confirmed that the water treatment media block is an efficient and economical method to maintaining the water quality of the ecological pond for a long time. The water treatment media block will be a great help in providing a better aquatic biotope space for aquatic insects and fishes living in clear water.

• Journal of Korean society of Dental Hygiene
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• v.10 no.3
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• pp.483-493
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• 2010

Objectives : The purpose of this study was to obtain the information for the improvement of the support in oder to expand the adjusted water fluoridation program to Myeong-dong water treatment plant in Gimhae city, Korea. Methods : Questionnaires were distributed to the parents of elementary schoolchildren and their responses were collected. All collected data were analyzed using the SPSS program. Results : The percentage of respondents using the tap water was 47.0% for drinking and 54.4% for cooking, respectively. The percentage of respondents using the water purified the tap water with the home water purifier was 45.1% for drinking and 36.2% for cooking, respectively. Respondents who knew the adjusted water fluoridation program was 48.3%. Respondents who knew the implementation of the adjusted water fluoridation program at the moment in Gimhae was 27.0%. 90.2% of residents agreed on the expansion of the adjusted water fluoridation program to Myeong-dong water treatment plant, Significant variables in the approval rates of the adjusted water fluoridation program were age, residence period, occupation, recognition of the program. Conclusions : It is desirable to expand the adjusted water fluoridation program to Myeong-dong water treatment plant in Gimhae as the percentage of respondents who agreed on the introduction of the program was high.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.869-875
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• 2011

Ministry of Environment has been promoting BTL business of the sewer rehabilitation which continues from 2005 up to now. Sewer rehabilitation is classified into three parts : wastewater pipe rehabilitation, rainwater pipe rehabilitation and drainage equipment rehabilitation. Drainage equipment rehabilitation is that drainage pipe connects wastewater pipe directly without water-purifier. In the drainage equipment construction, it is inevitable to have the damage of ground structures(wall, gate and U drain, etc) when an open excavation method is used. Therefore it is necessary to develop non-excavation method to connect drainage pipe and wastewater pipe like jacking method to avoid the damage of ground structure. This paper has conducted an analysis of the non-excavation method using a boring machine attached to backhoe, which is issued the verification certificate of environmental technology according to the Development of and Support for Environmental Technology Act, article.7. The index set in this analysis was sectionalized to the condition of construction, the grade of drainage pipe, the size of excavated hole, the amount of waste cement concrete and asphalt concrete and the benefit effect compared to open excavation method.