• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.16 no.1
• /
• pp.41-47
• /
• 2018

Radioactive substances, especially $^{137}Cs$ discharged in the course of Nuclear Power Plant Accident or maintenance of power plants, cause contamination of the soil. For habitation of residents and reuse of industrial land, it is inevitably necessary to decontaminate the soil. This study examines a soil washing process that has actually been used for washing of radioactive-contaminated soil. The soil washing process uses a washing agent to weaken surface tension of the soil and cesium, separating cesium from the soil. In this study, in order to raise the efficiency of the process, a flocculating agent was added to the washing water to remove fine soil and cesium. The cesium concentrations before and after applying the flocculating agent to cesium solution were measured through ICP-OES. When using 0.1 g of J-AF flocculating agent in the experiment, the maximum Cs removal performance was approximately 88%; the minimum value was 67%. Species combinations between cesium and soil were predicted using Visual MINTEQ Code; the ability to reuse the washing water or not, and the removal rate of the fine soil, determined via measurement of the turbidity after applying the flocculating agent, were determined.

• Analytical Science and Technology
• /
• v.35 no.6
• /
• pp.237-241
• /
• 2022

The effect of washing fingerprints deposited on glass that were contaminated with a flammable liquid (gasoline, kerosene, diesel, and thinner) was studied by washing with hexane or heptane. The fingerprints were visualized using fuming cyanoacrylate, followed by basic yellow 40 staining. After comparing the washing effect, by dividing one fingerprint into four sections, it was confirmed that the ridge detail was damaged by dissolving the fingerprints in flammable liquid. As a result of washing fingerprints contaminated with flammable liquids using hexane or heptane, fingerprints contaminated with gasoline, kerosene, and thinner did not show a washing effect because the ridge detail was damaged at the time of contamination, and only fingerprints contaminated with diesel exhibited improved ridge detail quality. Because hexane and heptane washing damage the ridge detail, it was found that fingerprints contaminated with gasoline, kerosene, and thinner were better enhanced directly without the washing process. In addition, it was found that the amount of the washing solvent and contact time should be minimized when washing fingerprints contaminated with diesel.

• Korean Chemical Engineering Research
• /
• v.51 no.6
• /
• pp.745-754
• /
• 2013

This study evaluated the optimal soil washing conditions for toxic metals considering the removal efficiency of toxic metals from contaminated soils as well as from soil washing effluents. In the contaminated soils, As was the major contaminant and extracted by sodium hydroxide solution better than by sulfuric acid. However, in the case of the treatment of soil washing effluents, sodium hydroxide was less effective extractant because soil organic matter extracted by sodium hydroxide prevented the solid-liquid phase separation and toxic metal removal. In the treatment of soil washing effluents with sulfuric acid, toxic metals in the effluents were mostly precipitated at the pH above 6.5. In addition, granular ferric oxide (GFO) as an adsorbent enhanced the removal of As and Pb indicating that toxic metals in the washing effluents can be removed almost completely by the use of combined adsorption-neutralization process. This study suggests that soil washing techniques for toxic metals should be optimized based on the physical and chemical properties of the contaminated soils, the nature of chemical extractant, and the removal efficiency and effectiveness of toxic metals from the soils as well as soil washing effluents.

• Journal of Applied Biological Chemistry
• /
• v.63 no.1
• /
• pp.51-60
• /
• 2020

This study was conducted to investigate changes in pesticide residues in eggplant and lettuce during washing and cooking processes after application with azoxystrobin. Eggplant was processed with running washing, steaming, and stir-frying, and lettuce was processed with soaking washing, running washing, soaking and running washing, ultrasonic cleaning, and blanching. The limit of quantitation of GC analysis of azoxystrobin was 0.01 mg/kg and the recovery rate was 84.7-109.5%. The azoxystrobin processing factors (PFs) and reduction rates in eggplant and lettuce were calculated and the results were as follows. In the case of eggplant, the azoxystrobin PF and reduction rate of running washing were 0.29 and 71.1%, respectively, those of steaming were 0.32 and 68.0%, respectively, and those of stir-frying were 0.24 and 75.7%, respectively. In the case of lettuce, the azoxystrobin PF and reduction rate of soaking washing were 0.25, 75.3%, those of running washing were 0.61 and 38.9%, respectively, those of soaking and running washing were 0.32, 68.0%, those of ultrasonic cleaning were 0.47 and 53.1%, respectively, and those of blanching were 0.26 and 73.6%, respectively. It could be identified that pesticide residues in eggplant and lettuce can be effectively reduced through washing and cooking processes and that most of pesticide residues were removed when cooking processes were undergone after washing. Therefore, azoxystrobin PFs after washing and processing can be provided as basic data for risk assessment.

• Korean Journal of Food Science and Technology
• /
• v.33 no.5
• /
• pp.534-539
• /
• 2001

To utilize oyster cannery processing waste water effectively, this study was carried out to prepare instant powdered soup using oyster wash water. Instant powdered soup from oyster hot-water extracts (HWE) was prepared by mixing oyster spray-dried hot-water extracts (15 g) with table salt (5 g), cream powder (19 g), milk replacer (12 g), wheat flour (20 g), corn flour (15 g), starch (5 g), glucose (7.5 g) and onion powder (1.5 g). In preparing instant powdered soup from oyster wash water (OWW), powder from oyster spray-dried wash water instead of the spray-dried hot water extracts, was added and other additives were added in proportion to those in the HWE. The OWW consists mainly of carbohydrates (71.1%). It was not different from the instant powdered soup from hot-water extracts. The volatile basic nitrogen, vaible cell counts, coliform group of instant powdered soup from oyster wash water contains 29.4 mg/100g, $4.6{\times}10^4\;CFU/g$, <18 MPN/100g, respectively and its water activity has 0.246. So it was a hygienically safe and conservable instant food. The main fatty acid of OWW was 16 : 0 and 18 : 1n-9. Its chemical score of protein was 59.4% and its main inorganic matter was iron. According to a sensory evaluation, in contrast to the HWE, the OWW had a slightly lower aroma but better taste. It was concluded from the above chemical and sensual evaluation that the oyster wash water can be used as a flavor enhancer for instant powdered soup.

• Korean Journal of Food Science and Technology
• /
• v.40 no.2
• /
• pp.171-177
• /
• 2008

The effects of hydrocooling and packaging type on the quality attributes of fresh-cut crown daisies (Chrysanthemum coronarium var. spatiosum) were investigated by examining weight loss, respiration, vitamin C content, total chlorophyll content, microbial load, and sensory properties during storage at 4 and 10$^{\circ}C$. Fresh crown daisies were trimmed and washed with cold water (1 and 5$^{\circ}C$) as well as tap water (10$^{\circ}C$) 3 times each for 30 sec. They were then packaged in PP (polypropylene) film bags or PETE (polyethylene terephthalate) trays, and stored for 9 days at 4 and 10$^{\circ}C$, respectively. In general, weight loss was reduced as a result of the washing and packaging. The respiration rate increased slowly during storage at 4$^{\circ}C$, and the vitamin C and total chlorophyll contents of the crown daisies packaged in PETE trays decreased gradually during storage. Finally, the treatments consisting of hydrocooling and then packaging in PETE trays resulted in approximately 1-2 log CFU/g reductions in microbial load.

• Korean Chemical Engineering Research
• /
• v.60 no.1
• /
• pp.169-174
• /
• 2022

In this study, a tandem water and hexane washing process was developed to improve the recovery efficiency of paclitaxel derived from Taxus chinensis. The polar impurities contained in the sample were effectively removed by washing with water at a sample/water ratio of 1:40 (w/v) for 10 min. In addition, the non-polar impurities were effectively removed by washing with hexane at a sample/hexane ratio of 1:160 (w/v) for 20 min. A high purity of paclitaxel (>30.0%) was obtained in a short operating time (~30 min) by sequential washing with water and hexane.

• Journal of Life Science
• /
• v.22 no.4
• /
• pp.565-568
• /
• 2012

There are various kinds of cereals used in sunsik manufacturing. Different harmful microorganisms that can contaminate these cereals have been reported. According to the different sizes of cereals used, black bean, black rice, and millet were artificially contaminated with Escherichia $Coli.$ $E.$ $coli$ contamination in cereal samples was detected after different washing steps under different conditions. The increase of washing time did not have any effect with regard to reducing $E.$ $coli$ in samples. Among several ratios between the washing solution and sample, 2:1 that have little influence to reduce $E.$ $coli$ contamination have been determined. The temperature of the washing solution is an influencing factor as well. Washing with solution at $40^{\circ}C$ could reduce 1 log of $E.$ $coli$ in samples. Among different concentrations of saline used as a washing solution, 5% could reduce 2~3 log $E.$ $coli$ in contaminated samples. However, the saline adds a salty taste to cereals when used during the washing step. To remove that, an extra washing step and large amount of washing solution are necessary in sunsik manufacturing.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.239-239
• /
• 2020

상수관망은 수용가에게 용수를 공급하는 사회기반시설물로, 용수를 공급하는 과정에서 관내에 이물질, 스케일 등의 생성은 불가피하다. 관로 변경, 단수로 인한 비상시 용수 공급 등의 유향 및 유속이 변화가 발생할 경우 스케일이 박리되어 적수사고 등의 수질문제가 발생 할 수 있으며, 이에 사전에 스케일을 제거 할 필요성이 있다. 스케일을 제거하기 위해서는 주기적인 관세척이 필요하며, 대표적인 공법으로는 플러싱공법이 있다. 현재까지 플러싱공법에 대한 연구는 실험을 통한 적용 권장 기준으로 진행되어 왔으나, 실제 상수관망에서 적용권장 기준을 확보하기 위한 방안에 대한 연구는 미흡한 실정이다. 플러싱공법의 대표적은 종류는 재래식 플러싱공법과 단방향 플러싱공법이 있다. 재래식 플러싱공법은 제수밸브를 조작하지 않는 방법으로, 모든 소화전에서 용수를 방출하는 공법이다. 단방향 플러싱공법은 제수밸브를 조작하여, 일정한 방향으로 요수를 방출하는 공법이다. 단방향 플러싱공법은 재래식 플러싱공법보다 유속확보 측면에서 유리하여 관로 세척을 위한 유량 및 유속 확보가 용이하다. 단방향 플러싱공법을 적용하기 위해서는 관로의 유속을 확보하기 위해 세척구역 정의하는 것이 필요하다. 이에 본 연구에서는 세척구역 정의를 통한 플러싱공법 적용 방안을 제안하고자 한다. 세척구역은 크게 3단계로 구분한다. 먼저 블록단위의 세척순서를 결정하고, 블록 내 관망 세척구역을 결정한다. 이때 관로의 관경, 곡선구간, 세척구역의 길이를 고려하여 세척구역을 정의한다. 마지막으로 결정된 세척구역을 제수밸브의 위치, 조작 횟수에 근거하여 세척순서를 결정한다. 본 연구를 통해 실제 상수관망 플러싱공법 적용 절차 수립에 기여할 수 있다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1999.10a
• /
• pp.87-89
• /
• 1999

본 연구에서는 Sorfactant/Cosolvent 혼합용액을 적용한 Soil flushing 기법에 의해 농약(Endosulfan(6,7,8,9,10,10-Hexachlor-1,5,5a,6,9,9a-hexahydro-6,9-methane-2,3,4benzo (e)dioxathiepin-3-oxide))으로 오염된 토양의 정화효율을 알아보았으며, 회분식 및 연속식 실험을 통하여 최적의 운전조건을 도출하고자 하였다. 세척용액의 적정 사용조건을 알아보기 위한 회분식 실험은 Jar tester를 사용하여 진탕비 (토양 중량 : 세척용액 부피), Surfactant(SDS ＋ POE$_{5}$, POE$_{9}$ ＋ POE$_{14}$, POE$_{5}$ ＋ POE$_{14}$, POE$_{14}$)와 보조용매(water, ethanol, methanol, ethanol＋methanol)의 혼합비 및 농도 조건을 변화시켜가며 토양세척을 수행하였다. 세척용액은 보조용매에 Surfactant의 농도를 0.5%, 1%로 용해하여 적용하였다. 연속식 실험은 회분식 실험에서 얻어진 최적 세척용액 사용조건 즉, 계면활성제 SDS + POE$_{5}$(1:1, 용액농도 1%), 보조용매 ethanol을 일정 비율로 혼합한 세척용액을 오염된 토양이 충진된 유리칼럼에 여러 유량조건에서 1 - 20 pore volume까지 통과시켜 각 통과된 pore volume에서의 토양세척 효율을 알아보았다. 본 실험조건에서 얻어진 세척용액의 최적 통과 속도는 0.31 ㎤$cm^{-2}$$min^{-1}$ 이었으며, 세척온도의 증가에 따른 세척효율의 향상은 2$0^{\circ}C$이상에서 크게 둔화되었다. 또한 보조용매의 사용량을 줄이기 위해 에탄올을 물로 1:3까지 희석한 결과 세척효율에 큰 영향이 없음을 알 수 있었다.