• Journal of Environmental Science International
• /
• v.16 no.1
• /
• pp.81-94
• /
• 2007

The purpose of this work is to investigate the water quality change characteristics of treated water in water distribution systems of Water Treatment Plants (WTPs) of Jeju City. For this, the raw water, treated water and tap water that did not pass (named as not pass-tap water) and passed through the water storage tank (named as pass-tap water) were sampled and analyzed monthly from September 2001 to August 2002, for four (W, S, B and O) WTPs except for D WTP (where treated water is not supplied continuously) among WTPs of Jeju City. The concentrations of $NO_3^-$ and $Cl^-$ of treated water in distribution systems changed little, but changed seasonally, which is considered to be based on the seasonal variation of the quality of raw water. The pH of treated water changed little in distribution systems for S WTP, but for the other WTPs, the pH of not pass-tap water was similar to that of treated water and the pH of pass-tap water was higher than that of treated water. The turbidity of treated water in distribution systems changed little except for W2 of W WTP and S4 and S5 of S WTP, where it was higher than that of each treated water. The residual chlorine concentrations between treated water and not pass-tap water changed little, but those between treated water and pass-tap water changed greatly, based on the its long residence time in water storage tank and so its reaction with organic matter, etc or its evaporation. The concentrations of TTHMs (total trihalomethanes) and $CHCl_3$ that induce cancers in water distribution systems of these WTPs, were much lower than their water quality criteria and those in other cities. The concentrations of TTHMs of treated water and not pass-tap water were similar, but concentrations of pass-tap water were 1.5 to 2.0 times higher than those of treated water and not pass-tap water, due to the reaction of residual chlorine and organic matter, etc, with the result of long residence time in water storage tank.

• Journal of Environmental Science International
• /
• v.24 no.7
• /
• pp.907-915
• /
• 2015

The tap water is generally known to be corrosive in the pH range at 6.5 ~ 7.5. And the degree of corrosion varies depending on the types of raw water such as river surface water or lake water of the dam. Although several corrosion index represents the corrosivity of tap water, the typical corrosion indexes such as Langelier saturation index (LI) and calcium carbonate precipitation potential (CCPP) were calculated to monitoring the corrosive water quality about raw and tap water in water distribution system. To control the corrosive water quality, the correlation between corrosion index and water quality factors were examined. In this study, corrosion index (LI, CCPP) and the pH was found to be most highly correlated.

• Journal of Environmental Health Sciences
• /
• v.10 no.2
• /
• pp.41-51
• /
• 1984

This study was performed using samples collected at Myungryundong and at Reservoirs. The purpose of this study was to investigate the differences of water quality between tap and raw water, and to analyse drinking water quality by Fe, Zn from corroded galvanized steel pipe. Results were as follows 1. The older the pipe was, the higher the concentration of Ferrum and Zinc was (t-test : p<0.05). Ferrum and Zinc also exceeded the limits in the older galvanized steel pipe. I think that this comes from the corrosion of pipe. 2. Mercury, Arsenic, Cadmium, Lead, Chomium, Argentum and Aurum not detected in raw water were not detected in tap water. Cobalt, Bismuth and Molybudenum detected in raw water were not detected in tap water. I think that this comes from the quality of raw water, the result of water treatment and the improbability of detection of above metals in water delivery system. 3. Silicon measured 2.4698ppm in raw water, but it ranged from 0.4769ppm to 1.982 ppm in tap water. Manganese measured 0.0638ppm in raw water, but it ranged from 0.0026ppm to 0.0198ppm in 17cases(31%) out of 55samples in tap water. I think that this comes from the water treatment. 4. Aluminium not detected in raw water was found in 17 cases (31%) out of the samples (55cases). It may be considered as the use of coagulants $Al_2(SO_4)_3$. $18H_2O$ and PAC (Poly Aluminium Chloride). The concentration of copper in tap water was much higher in 2 cases(3.6%) out of the samples(55) than that of copper in raw water. I think that this may come from the use of ${CuSO}_4$, the preventive of algae growth, and the result of chlorination, but further study must be necoessary to support the proof.

• Journal of Preventive Medicine and Public Health
• /
• v.21 no.2 s.24
• /
• pp.284-294
• /
• 1988

To measure the mutagenic activity of micro-organic pollutants in drinking water, mutagenicity test was conducted using Salmnella typhimurium TA 98 strain on the water sample taken from three water supply stations and six tap water in Seoul in July and November 1987. The results were as follows : 1. The average amounts of organic matters in raw, treated, and tap water sampled in July were 0.38mg/l, 0.28mg/l, and 0.45mg/l. respectively, and sampled in November were 0.34mg/l, 0.24mg/l, and 0.22mg/l, respectively. The amount of organic matters of tap water sampled in November did not increase while that of tap water sampled in July increased compare to those of raw or treated water. 2. The amount of organic matters is the highest in neutral fraction compare to acidic and basic fractions. 3. In the five out of six tap water and raw water of Paldang and Kuui station sampled in July, the mutagenicity ratios were greater then two (both direct and indirect mutagenicity). 4. In the three out of six tap water and raw and treated water of Kuui station sampled in November, the mutagenicity ratios were greater than two. 5. While mutagenic activities were low in acidic and basic fraction, they were high in neutral fraction. The samples which had high mutagenic acitivity in the total amount also showed high mutagenic activity in neutral fraction. 6. While mutagenic acitivity was decreased after the treatement of water, it was increased in tap water as the distance from the water supply station increases.

• Journal of Environmental Science International
• /
• v.9 no.5
• /
• pp.423-428
• /
• 2000

The characteristics of Far-infrared rays mineral water(FIR water) have been compared to the tap water by means of relationship between FIR water and Nuclear Magnetic Resonance spectroscopy(NMR), FIR water and thermography FIR water and velocity of blood FIR-water and pH, FIR water and dissolved oxygen(DO), FIR water and Oxidation-Reduction Potential(ORP) using the development FIR water purification of grand prix system. From the experimental result are quite satisfactory when compared with the tap water. Also the FIR water were evaluated to see if those are tasty and healthy using the Hashimoto's Mineral Balance Index. As a result FIR-water was found as tasty and healthy.

• Journal of Korean Society on Water Environment
• /
• v.27 no.3
• /
• pp.334-341
• /
• 2011

The free residual chlorine of tap water samples, collected from 266 faucets on the water pipe network in Daegu City, was between 0.1 and 0.79 mg/L. On microorganic tests, general bacteria and the coliform goup were not detected and thus the tap water was turned out to be fit to drink. In particular, samples of which free residual chlorine was 0.1 mg/L and over were cultured in R2A agar media at $25^{\circ}C$ for 7 days, and as a result heterotrophic bacteria were detected in 65.9% of samples; (1). The closer tap water got to the faucet from the stilling basin, the lower residual chlorine concentration became but the more the bacterial count became. And, more bacteria were detected in the R2A agar medium than in the PCA medium. (2). In the case of separated strains, most colonies were reddish or yellowish. 16S rRNA sequence was identified as Methylobacterium sp. and Williamsia sp., and yellow strain was identified as Sphingomonas sp., Sphingobium sp., Novosphingobium sp., Blastomonas sp., Rhodococcus sp. and Microbacterium sp. White strain was identified as Staphylococcus sp. (3). Sterilized tap water in polyethylene bottles was inoculated with separated strain and was left as it was for 2 months. As a result, bio-film was observed in tap water inoculated with Methylobacterium sp. and Sphingomonas sp. It was found that heterotrophic bacteria increased when free residual chlorine was removed from tap water in the water pipe network. Thus, there is a need to determine a base value for heterotrophic bacteria in order to check the cleanliness of tap water in the water pipe network.

• Korean Journal of Ecology and Environment
• /
• v.49 no.3
• /
• pp.208-214
• /
• 2016

We analyzed research trend and public perception related with tap water to identify major factors affecting low consumption of tap water. 805 research articles were collected for text mining analysis and 1,000 on-line questionnaires were surveyed to find social variables influencing tap water intake. Based on the word network analysis, research topics were divided into 4 major categories, 1) drinking water quality, 2) water fluoridation, 3) residual chlorine, and 4) micro-organism management. Compared with these major research topics, scientific studies of drinking behavior, or social perception were rather limited. 22.4% of total respondents used tap water as drinking water source, and only 1% drank tap water without further treatments (i.e. boiling, filtering). Experience of quality control report (B=0.392, p=0.046) and level of policy trust (B=1.002, p<0.0001) were influential factors on tap water drinking behavior. Age (B=0.020, p=0.002) and gender (B= - 1.843, p<0.0001) also showed significant difference. To increase the frequency of drinking the tap water by social members, the more scientific information of tap water quality and the water policy management should be clearly shared with social members.

• Journal of the Korean Dietetic Association
• /
• v.1 no.1
• /
• pp.31-42
• /
• 1995

The aims of this study are to enhance the students' knowledge of the drinking water and its reliability by investigating drinking water situation and the degree of students' knowledge on the drinking water. The results are as follows 1. Status and drinking behavior about school drinking water (1) 97.53% of the schools are using the tap water as the resource of drinking water (2) 46 schools are in possession of water tank and 18 schools of them are using the water tank as the resource of drinking water. The cleaning and sanitization of the tank are carried out once in a year with hypochloronatrium by the low-level officials, nurse teachers, and dietitian. 2. The degree of students' knowledge about drinking water (i) This survey represent that students favor the spring water best and think the tap water worst for drinking. (2) 83% of the students think that the tap water is polluted and these conception are formed mostly by the mass communication. 80% of boys and 90% of girls answered they don't drink plain tap water.

• Applied Biological Chemistry
• /
• v.31 no.1
• /
• pp.46-51
• /
• 1988

The effects of temperature on the water uptake rate of soybeans soaked in tap water and 0.5% $NaHCO_3$ solution were studied. The higher the soaking temperature, the faster the hydration rate, and among the three soybean varieties (Tanyob, Kwanggyo and Saeal), Tanyob(the smallest variety) showed faster rate than ocher varieties when soaking in tap water and 0.5% $NaHCO_3$ solution. Activation energy due to weight increase was calculated using Arrhenius equation. z-Values calculated from weight changes to reach different degrees of hydration during soaking showed the tendency to decrease with the increase of hydration degree when soaking in tap water and 0.5% $NaHCO_3$ solution.

• Journal of Digital Convergence
• /
• v.16 no.9
• /
• pp.399-404
• /
• 2018

The purpose of this study is to raise the drinking rate of Arisu, the tap water in Seoul, and to propose new solution for continuous water quality management and raising awareness. The research scope was limited to point-of-use water treatment system, and based on the this contents I proceed this study how this will help to increase direct drinking rate of Arisu. Through research, Korea has provided users with the ability to filter contaminated tap water simply as water to be rinsed through water purification. Therefore, it was predicted that it would be difficult to improve tap water as drinking water. With this study, I expect that the strength of point-of-use system and the reliability of tap water quality will be raised and hope various product will be developed to improve the perception as drinking water and I also expect that this can be applied to whole country even further in the scope of Seoul city.