• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.930-934
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• 2006

In this study, we conducted water-quality analysis of wastewater and in-situ flow measurement using automatic flow rate measuring instrument to identify characteristics of wastewater in urban areas, and collected samples in gutter fur storm water drain, rainfall bucket, and aqueduct of pipe from roof, and outfalls of basins to examine the contribution by pollution origins such as base wastewater, atmospheric washing, runoff by roof surface, runoff by road surface, erosion of sewer sediment. In the result, the concentration of pollutants reached peak in the beginning of rainfall due to first flush, was 3 to 10 times higher than average concentration of dry period, and was lower than that of dry period due to dilution of storm water. In the analysis of the contribution by pollution origins, the ratio of load by sewer sediment resuspension to the total pollution load was 54.6% fer COD, and 73.3% fur SS. Accordingly, we can reduce the total pollutant load by periodical dredging and washing of sewer sediment, and control the loadings by overflow of combined sewer overflows.

• Journal of Korean Society on Water Environment
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• v.40 no.1
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• pp.36-46
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• 2024

Microplastics in water resources have been recognized as a serious problem. The discharge of microplastics from wastewater treatment plants is considered a major contributor to environmental pollution in water resources. However, a reliable analytical method for quantifying microplastics in wastewater treatment plants has not yet been established. This study proposes a reliable, quick, and easy analytical method for quantifying microplastics. For the removal of organic particles, preprocessing steps were applied including oxidation, sonication, washing, and sieving. Nile Red staining was used to visualize microplastics, and quantitative analysis was conducted using fluorescent imaging. The stained microplastics were ultimately quantified through image analysis software. Among the preprocessing steps, sonication and washing stages were particularly effective in efficiently removing interfering substances from wastewater, enhancing the accuracy of the microplastic analysis. Additionally, various solvents (methanol, acetone, and N-hexane) for the Nile Red staining solution were tested. When N-hexane was applied as the solvent, the quantity of stained microplastics was lower compared to methanol and acetone. This suggests that N-hexane has a greater potential of reducing false staining and counting of non-plastic particles. In summary, this research demonstrates a robust method for quantifying microplastics in wastewater treatment plants by employing effective preprocessing steps and optimizing the staining process with Nile Red and N-hexane.

• Environmental Analysis Health and Toxicology
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• v.11 no.1_2
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• pp.19-29
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• 1996

Human exposure to volatile compounds in tap water can occur from inhalation and dermal absorption as well as direct ingestion. The relative contribution to total human exposure from these pathways has been considered to be important especially for VOC's (volatile organic compounds). In an attempt to reduce the uncertainty of the risk assessment, it has been suggested that the exposure assessment process could be significantly improved by adopting Monte-Carlo simulation. However, there is no actual data in Korea for each exposure parameter to determine the level of exposure, and the distributional pattern. Therefore, we surveyed water use patterns and behavior related to multi-route exposure to VOC's in household tap water in Korea, and compared these values to the those in western countries. In the first survey, we calculated daily water intake using data from a sample of 1322 persons of several cities in Korea. In the second survey, we obtained questionnaire data on exposure time for showering, bathing and household activities, and tap water intake from 851households in Korea. In the last survey, we measured the exposure parameters (exposure time, water use rate etc.) related to showers, baths, toilets, dish washing, washing and cooking, and tap water intake was surveyed. Also, the subjects were measured their body weight, height and tidal volume, etc. A diary, a flow meter and a measuring cup were used to measure these values as precisely as possible. Average daily water intake was ranged 0.79-1.71 L/day for adults in three surveys. Tap water intake measured by log-sheet during one week in third survey was 1.26 (average), 1.98 L/day (90 percentlie), respectively. These results were comparable with results from EPA (1.4, 2L/day). The average amount of water used by housewives in the third survey was 515.0 $\pm$ 564.6L/day. In usual activity, the amount of water used in the bathroom, the laundry and the kitchen was 140.0 $\pm$ 538.9, 148.0 $\pm$ 174.5, 229.3 $\pm$ 205.4 L/day, respectively. Exposure parameters such as water intake rate, exposure duration, body weight, inhalation rates in surveyed data of Korean people differed from those published from western countries. This could be attributed to variations in lifestyle, dietary habits and physiological characteristics.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.551-556
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• 2019

Recently, due to the fact that the mineral content in the wash water of the GAP-certified melon exceeds the GAP wash water standards, there are cases where the certification cannot be maintained. Therefore, agricultural industry demand requesting relaxation of the inorganic elements standard for water quality has been increasing, taking into account the consumption characteristics of Korean melon, which is eaten after removing the peel. This study was conducted to evaluate the human risks of four inorganic materials (fluorine, arsenic, iron and manganese) based on the water quality data of 142 samples of groundwater that was used for washing GAP-certified Korean melon in Seongju area from 2017 to 2019. As a result, the HQ of four minerals in Koreans who consumed groundwater used for washing GAP-certified Korean melons in the Seongju area was below 0.10 on average. In particular, in the case of iron and manganese which are esthetic influence substances, the average HQ was 0.00. The overexposure group showed 0.01, which was lower than the HQ (average 0.01, overexposure group 0.03) of the group that consumed Korean melon. Based on all the results, even if the groundwater of the Seongju area is used to wash GAP-certified Korean melon, the impact from these four inorganic materials, including iron and manganese, for Korean population consuming Korean melon will be minimal.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.330-335
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• 2014

This study was conducted to investigate residue levels of chlorantraniliprole and ethaboxam in inner part and outer leaves of a head-type Korean cabbage. Further, reduction of residues was measured after water washing, blanching and heat-cooking of the outer leaves. For chlorantraniliprole, residues in inner part and outer leaves were <0.01 mg/kg and 0.0757 mg/kg, respectively, in case of three-time spraying 30 days before harvest and <0.01 mg/kg and 1.19 mg/kg, respectively, in case of four-time spraying 10 days before harvest; for ethaboxam, <0.05 mg/kg and 0.216 mg/kg, respectively and <0.05 mg/kg and 1.18 mg/kg, respectively. Chlorantraniliprole and ethaboxam were not detected in inner part of the head-type Korean cabbage. Residue levels in outer leaves were very high as 10-100 fold as those in inner part of the cabbage. Therefore, there is no concern for safety of pesticide residues on kimchi prepared with the inner part of a head-type Korean cabbage. In addition, it needs to be noted that outer leaves should be carefully removed at harvest of the cabbage. Outer leaves water washed and blanched are called as Woogeogi, which is consumed after heat-cooking. In Woogeogi, residue concentrations of two compounds reduced to less than 10%, and further less than 5% by heat-cooking. This indicates that considerable amount of the test pesticide residues in outer leaves of a head-type Korean cabbage removed through water washing, blanching and heat-cooking.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.557-566
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• 2005

The purpose of this study was to estimate the microbial quality of some raw vegetables and to suggest a safer method of sanitization and pre-preparation in foodservice operations. The production of Dotori-muk muchim was monitored from ingredient preparation to final product and during holding at different temperatures. Three sanitization methods were performed during the preparation with crown daisy (tap water, chlorine water, electrolyzed water). The largest reduction of microbial counts was for electrolyzed water (after treatment, total plate counts were decreased to $2.76{\sim}3.76$ Log CFU/g, coliform counts were not detected). In the case before immersed in chlorine water, Performed first washing is larger the effective reduction of microbial counts than or not.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.09a
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• pp.39-64
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• 1996

Probably over most of recorded time, the quality of drinking water has been praised for good health and blamed for bad health. Certainly it is true, considering pathogenic organism that cause typhoid fever, giardiasis, etc., or considering chemical contaminants suspected of causing cancer. Drinking "natural" waters with a high mineral content is generally accepted to be healthy. Water containing very low levels of total dissolved solids (TDS), such as distilled water, is believed by some to help "cure" arthritis by "washing out" calcium from deposits in joints. Along with this reasoning, many believe that drinking very tow TDS water, treated by distillation, reverse osmosis (RO) or deionization (DD, "leaches" minerals from the body and causes mineral deficiencies with subsequent ill health effects.cies with subsequent ill health effects.

• Clean Technology
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• v.18 no.4
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• pp.390-397
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• 2012

Removal characteristics of lead-contaminated soil at the military shooting range located in the Changwon city were studied experimentally using soil washing process. As a washing solution, hydrogen chloride (HCl) concentrations of 0.001, 0.01, 0.1 and 0.2 N were used, and soil : solution ratios were 1 : 2, 1 : 3, 1 : 4, and 1 : 5. Particle diameter of contaminated soil of 4-0.075 mm, and washing period of 5, 10, 15, 20, 30, 60, and 120 min were used as operating parameters. The optimum concentration of HCl solution was 0.1 N (56.3% of Pb removal efficiency) with 15 minutes operation period in views of economics, and the optimum soil : solution ratio was determined as 1 g : 3 mL for 69.7% of Pb removal efficiency with 0.1 N HCl and 15 minutes washing period. As washing period increased, removal efficiency was increased until 20 min of the removal efficiency of 75.3%, and then almost stable. Pb removal efficiency in soil particle diameters of 0.075 mm or more was ranged from 77.0% to 82.0%, but it was decreased to 52.8% in diameter of less than 0.075 mm. Therefore, the optimum cut-off size of the soil particle diameter was found less than 0.075 mm. Combined HCl solution and ultrasonic washing method showed better removal efficiency compared to only water or HCl washing method for particle sizes above 0.075 mm.

• Food Science and Preservation
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• v.6 no.4
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• pp.417-423
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• 1999

Quality changes of crown daisy and kale were investigated during storage at 10$^{\circ}C$ after washing with cooled electrolyzed acid water at 3 times in 2 min. Total count and coliform count of crown daisy and kale after immersion in electrolyzed acid water were decreased to 1/130 and 1/1,170 of non-immersed crown daisy and to l/870 and l/470 of non-immersed kale. However total count and coliform count were increased to the similar levels of non-immesed and tap water immersed one after 6 days of storage. Weight loss of crown daisy and ka1e were lower than others for 3 days of storage but higher than that of one after that time. Decay rate of crown daisy and kale immersed electrolyzed acid water showed lower than that of non-immersed and tap water immersed one for 6 days. In case of kale, rupture strength was higher than others at just after immersion and showed similar values after initial storage period. Color value of both crown daisy and kale showed high L, b and low a value in the order of electrolyzed acid water, tap water and non-treatment. Chlorophyll content of crown daisy and kale were lower than those of others just after immersion in electrolyzed acid water, but showed rapid reduction in the order of non-treatment. tap water and electrolyzed acid water after 6 days. Overall organoleptic properties of crown daisy and kale in immersion electrolyzed acid water were higher than those of others.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.357-364
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• 1997

The objective of this study was to find optimum nonionic surfactants for clean up of soils contaminated by hydrocarbon oils. PIT(phase inversion temperature) measurements in ternary systems containing pure hydrocarbons, pure nonionic surfactants, and water were carried out and interfacial tensions were measured as a function of time for n-hexadecane oil drops brought into contact with various mixtures of nonionic surfactant and water. Batch surfactant washing experiments were performed based on the measurement, results of PIT and interfacial tension and the results showed that maximum removal of n-hexadecane occurred at the PIT of the system. For the $C_{12}E_5(C_{12}H_{25}O(CH_2CH_2O)_5H)$ system, maximum n-hexadecane removal of 73.4% occurred at the PIT of $52^{\circ}C$. In contrast, n-hexadecane removal at $25^{\circ}C$ and at $60^{\circ}C$, each corresponding to the conditions of below PIT and above PIT of the system, was found to be 57.1% and 57.0% respectively. The maximum removal of a hydrocarbon at the PIT of a system, where the hydrophilic and hydrophobic properties are balanced, was found to be due to the existence of high oil solubilization into a middle-phase microemulsion and ultralow interfacial of the order of $10^{-2}$ to $10^{-3}$ dyne/cm between middle-phase microemulsion and excess oil phase.