• Fashion & Textile Research Journal
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• v.8 no.1
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• pp.134-138
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• 2006

The washing efficiency of two types of washing machine- drum(drum washing) and drum using steam jet system(steam drum washing) was studied. The purpose of this paper is to clarify the performance of new steam drum washing. The relationship between washing temperature and washing efficiency(reflectance(%)) by soil removal, and that between washing temperature and electric energy consumption, Fabric damage evaluated by Danish wear method, Fabric shrinkage(%) during laundering were investigated, and compared with those in drum washing machine. Washing efficiency of steam drum washing according to washing temperature is better than that of drum washing. Electric energy consumption and fabric damage in steam drum washing are lower than those of drum washing. Fabric damage increased as washing temperature increased. Shrinkage of fabrics in steam drum washing and drum washing are about same. Therefore, we assumed that in the case of steam drum washing using steam jet system, washing efficiency remarkably increased, and fabric damage decreased, even with a lot of saving in given electric energy and water used.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.241-255
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• 2022

In this study, sieve analysis testing was performed on weathered granite soil from Yecheon (eastern South Korea) before and after water washing in accordance with the sieve analysis regulations of KS F 2302. The changes in particle separation and particle size distribution after washing with water were analyzed. Image analysis using an optical microscope revealed that soil particles were separated into smaller particles by water washing. The change in the particle size distribution curve was assessed using five index values. The increase in the fine particle fraction (<0.075 mm) was 13.67%, the increase in the 0.075-0.25 mm fraction was 19.44%, and the mean particle diameter (D₅₀) decreased by 0.663 mm. In addition, the maximum passage width (B_M) of the particle size distribution curve increased by 21.08% for the #30 sieve, and the moving area (A) of the particle size distribution curve was 69.28%·mm. These results suggest that washing with water is an effective way to prevent underestimation of the fine particle content in soil.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1329-1336
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• 2011

The objectives of this study are to examine the processing of oils contamination soil by means of using a micronano-bubble soil washing system, to investigate the various factors such as washing periods, the amount of micro-nano bubbles generated depending on the quantity of acid injection and quantity of air injection, to examine the features involved in the elimination of total petroleum hydrocarbons (TPHs) contained in the soil, and thus to evaluate the possibility of practical application on the field for the economic feasibility. The oils contaminated soil used in this study was collected from the 0~15 cm surface layer of an automobile junkyard located in U City. The collected soil was air-dried for 24 hours, and then the large particles and other substances contained in the soil were eliminated and filtered through sieve No.10 (2 mm) to secure consistency in the samples. The TPH concentration of the contaminated soil was found to be 4,914~5,998 mg/kg. The micronano-bubble soil washing system consists of the reactor, the flow equalization tank, the micronano- bubble generator, the pump and the strainer, and was manufactured with stainless material for withstanding acidic phase. When the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 30 minutes were respectively identified as 4,931 mg/kg (18.9%), 4,678 mg/kg (18.9%) and, 4,513 mg/kg (17.7%). And when the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 120 minutes were respectively identified as4,256 mg/kg (22.3%), 4,621 mg/kg (19.7%) and 4,268 mg/kg (25.9%).

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.104-111
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• 2004

Several tests were conducted to optimize design parameters of soil washing technique for arsenic contaminated tailings and soils. Arsenic contaminated tailings and soils have been sampled from the N nine, Kwangwondo and the K mine, Kyungsangbukdo, respectively. According to the result of sequential extraction procedure, total arsenic concentrations were 21,028 $\pm$ 190, 443$\pm$7, and 37$\pm$3 mg/kg, for mine tailings, dry field, and river sedimentary soil, respectively. The subtotal of weakly bonded and easily releasable arsenic concentrations which were 2,284$\pm$100 (10.9%), 151$\pm$5 (34.0%), 15$\pm$3 (39.5%)mg/kg for mine tailings, dry field, and river sedimentary soil, respectively. Kinetics of arsenic extraction using NaOH showed that arsenic was extracted more than 90% after 6 hours for all samples. The optimized concentration of NaOH were 200 mM for all samples while the optimized dilution ratio were different to have 1:10 (mine tailings) and 1:5 (dry field, river sedimentary soil), respectively. Results of sequential soil washing tests using NaOH showed that arsenic concentrations obtained by Korean Standard Test Procedure were decreased to meet the regulation for both river sedimentary soil and dry field while they were not decreased largely for mine tailings, even though NaOH had much higher efficiencies of arsenic extraction than other extractants.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.02a
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• pp.61-73
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• 2001

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1076-1086
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• 2010

Soil remediation technologies were experimented to evaluate whether the technologies could be used to apply remediation of contaminated marine sediment. In this research, marine sediments were sampled at "Ulsan" and "Jinhae" where remediation projects are considered, and then the possibility of heavy metal removal was evaluated throughout the technologies. Heavy metal concentration of silt and clay fraction was higher than that of sand fraction at "Ulsan". Heavy metal removal of the silt and clay fraction was arsenic (As) 81.5%, mercury (Hg) 93.8% by particle separation, cadmium (Cd) 72.2%, mercury (Hg) 93.8% by soil washing technology, cadmium (Cd) 70.8%, lead (Pb) 65.6% by another soil washing technology. Based on experimental results, tested particle separation and soil washing technologies could be used to remove heavy metals of sand fraction and silt and clay fraction. Heavy metal removal by soil washing technology which was composed of separation, washing and physical or chemical reaction by additives such as acid, organic solvents was more effective comparing to that of particle separation. Since heavy metal concentration of all treated samples was suitable for national soil standards, all the tested technologies were could be used not only to remove heavy metals of marine contaminated sediment but also to reuse treated samples in land.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.36-46
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• 2021

The Soil Health Index (SHI) developed by Park et al. (2021) is used to evaluate soil health on remediated soils collected from several remediation project sites and monitored the changes of SHI during the remediation process of land farming, soil washing, and thermal desorption. In the case of land farming, the soils remediated below a legal standard didn't show any significant changes in indices of SHI except the downgrade of available phosphate from medium to a low level. The SHI scores were ranged from 52 to 56 in the contaminated soil and 54 to 57 in the remediated soil. With soil washing, bulk density changed from high to a low level, and available phosphate was lowered from medium to low level. As the SHI scores were evaluated as 58 to 63 for contaminated soil and 38 to 42 for remediated soils. For thermal desorption, soil respiration rate was reduced from high to low level and SHI was scored as 50 to 51 for contaminated soils and 43 to 47 for remediated soils. Even though any abrupt changes of the SHI in remediated soils were not identified in the soils used in this study, it is expected that soil in different conditions such as types and concentrations of contaminant and soil characteristics would result in distinguished changes of the SHI. There is a room for more studies collect diverse information on SHI across the country.

• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.74-83
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• 2020

In this study, the effect of hydrochloric acid (HCl) concentrations on removal efficiency and chemical forms of heavy metals in dredged sediment during acid washing was investigated. The removal efficiencies of Zn, Cu, Pb, Ni and Cd by acid washing were 18.4-92.4%, 7.2-83.7%, 9.4-75%, 8.1-53.4% and 34.4-70.8%, respectively. Overall, the removal efficiencies of heavy metals were remarkably enhanced with the increase of the acid strength. However, the removal efficiencies for 0.5 and 1.0 M HCl were comparable, and both cases met the Korean soil contamination standard. Based on the sequential extraction results, concentration of the exchangeable fraction (F1), the most labile fraction, increased whereas concentrations of the other fractions decreased with increasing acid strength. Particularly, the carbonate (F2) and Fe/Mn oxides (F3) fractions drastically decreased by using 0.5 M or 1.0 M HCl. The current study results verified that acid washing could effectively reduce heavy metal concentrations and its potential mobility in dredged sediments. However, the study also found that acid washing may cause significant increase in bioavailable fraction of heavy metals, suggesting the need to evaluate the changes in chemical forms of heavy metals by acid washing when determining the acid strength to be applied.

• Journal of Soil and Groundwater Environment
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• v.26 no.6
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• pp.27-35
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• 2021

This study examined the possibility of reutilization of soil reclaimed from contaminated sites after completing remediation. The current status of soil remediation methods in Korea was reviewed and physicochemical properties of soil before and after remediation processes were examined to access the recycling possibility of reclaimed soils based on Recycling Aggregate Quality Standard. The most commonly practiced soil remediation techniques are soil washing, land farming, and thermal desorption. These techniques tend to deteriorate various soil properties including electrical conductivity(EC), organic matter content(OM), available P₂O₅, and cation exchange capacity(CEC). Evaluation of the properties of soil retrieved after each remediation process indicated soil washing may yield the most suitable soil for use as a filling, covering, back-filling, road pavement, and blocking materials, In addition, the soils reclaimed from land farming and thermal desorption have potential utility as a filling, covering and road pavement materials.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.49-55
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• 1999

The treatment of petroleum contaminated soil requires various physico-chemical remediation technologies which are efficient in time and can reduce the possibility of secondary contamination by themselves In this study, an innovated soil washing process was proposed to treat the diesel-contaminated soil. Micro-bubbles, which were generated by hydrogen peroxide, deserted and floated the contaminants. Soils less than #60(0.25mm) were artificially contaminated by 6,500mg TPH/kg dry soil initially. The process was examined for pH, the soil to water mixing ratio, concentration of $H_2O$$_2$, and contacting times. In the case of less than #60 soil, maximum removal efficiency(60%) was obtained at pH 12. 1.0% hydrogen peroxide, and 1 : 5 soil to water mixing ratio for 1 hour.