• Journal of Soil and Groundwater Environment
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• v.17 no.4
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• pp.9-18
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• 2012

This study was carried out to leach valuable metal ions from the mine waste ore using the adapted indigenous bacteria. In order to tolerance the heavy metals, the indigenous bacteria were repeatedly subcultured in the adaptation-medium containing $CuSO_4{\cdot}5H_2O$ for 3 weeks and 6 weeks, respectively. As the adaptation experiment processed, the pH was rapidly decrease in the adaptation-medium of 6 weeks more than the 3 weeks. The result of bioleaching with the adapted bacteria for 42 days, the pH value of leaching-medium in the 3 weeks tend to increased, whereas the pH of the 6 weeks decreased. In decreasing the pH value in the adaptation-medium and in the leaching-medium, it was identified that the indigenous bacteria were adapted $Cu^{2+}$ the ion and the mine waste ores. The contents of Cu, Fe and Zn in the leaching solution were usually higher leached in 6 weeks than 3 weeks due to the adaptation. Considering the bioleaching rates of Cu, Fe and Zn from these leaching solutions, the highest increasing the efficiency metal ion were found to be Fe. Accordingly, it is expected that the more valuable element ions can be leached out from the any mine waste, if the adapted bacteria with heavy metals will apply in future bioleaching experiments.

• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.1-11
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• 2023

The phenomenon of sediment resuspension in rivers and lakes causes contaminants (heavy metals and nutrients) accumulated in the sediment to leach into the overlying water. As a result, it can lead to changes in toxic effects and eutrophication in the aquatic ecosystem. In this regard, it is important to quantitatively determine the amount of contaminants leached during sediment resuspension. In this study, methods for assessing the amount of released contaminants and the types of contaminants potentially released due to sediment resuspension were studied and summarized. Methods for assessing leaching can be divided into three groups based on the principle of causing resuspension: (i) the oscillating grid chamber method, (ii) the mechanical stirrer method, and (iii) the shaker method. It was confirmed that the types of contaminants that can potentially be released include heavy metals bound to sulfides, as well as exchangeable and labile forms of heavy metals and nutrients. To effectively manage stable aquatic ecosystems in the future, a simplified leaching test method is needed to assess in advance the risks (i.e., changes in toxic effects and eutrophication) that sediment resuspension may pose to aquatic ecosystems.

• Journal of Soil and Groundwater Environment
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• v.29 no.1
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• pp.39-50
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• 2024

Slags from steel-making industry have been recycled at a target rate of 95% and most of them are recycled as media-contact type such as fill and cover materials in Korea. However, as they contain free phase CaO during their generation, they may not only expand and collapse upon contact with water, but high pH leachate and heavy metals leaching may occur. In this study, the Korean leaching procedure (KLP) and up-flow percolation test were performed for the samples collected from 17 steel-making production plants in Korea. The waste quality criteria were met in all tests, but pH of the samples was above 10. There are no regulations on the pH of leachate in most of the countries, however, Germany, Italy, and Australia have set a pH range of 10 to 13 for the leachates. Although slag leachate cannot be considered hazardous based only on its high pH, it is necessary to reduce the pH of leachate to minimize the impact on the surrounding environment. Furthermore, conflicting regulations on wastes handling and management in Korea created confusion on the types of wastes subject to recycling. Therefore, an appropriate management plan for steel-making slags needs to be established. To this end, this study attempted to provide a guideline for managing steel-making slag waste by considering international guidelines and current management practices in Korea.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.95-98
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• 2003

Waste lime is produced as by-products in chemical industry, Reuse of waste lime mixed with soil for banking and backfill material in civil works was analysed in this study. For this purpose, environmental effect of waste lime admixtures was tested. Thus, this study presents the leaching characterization of waste lime in laboratory batch and column tests. Countermeasure for reduction of environmental effects was suggested from the test results.

• Economic and Environmental Geology
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• v.34 no.5
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• pp.461-470
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• 2001

The Shihung mine was restored in the early 90's after abandonment for 20 yews since 1973. Although disposed mine tailings were removed and the site was replaced by an incineration plant, still some residual mine tailings remain in the places including the old mine tailing ditposal area and the adjacent agricultural area. These residual mine tailings are prone to impose an adverse impact on the soil and groundwater and needs investigation for the potential contamination. Mine tailing samples were collected from the old tailing disposal area and the iii paddy. The porewater from the mine tailing were extracted and analysed to investigate chemical changes along the reaction path. Batch leaching tests were also carried out in the laboratory to find any supporting evidence found in the field analysis. Evidence of elemental leaching was confirmed both by the mine tailing and the porewater chemistry in them. The element concentrations of Cu, Cd, Pb, Zn in the porewater exceed the standard for drinking water of Korean government and US EPA. Leaching of heavy metals from the mine tailing seem to be responsible for the contamination. In batch leaching test. heavy metals were either continuous1y released or declined rapidly. Combining the information with porewater variation with depths and the geochemical meodeling results, most of elements are controlled by dissolution and/or precipitation processes, with some solubility controlling solid phases (Cu, Pb, Fe and Zn). Batch leaching test conducted at fixed pH 4 showed much higher releases for the heavy metals up to 400 times (Zn) and this area is becoming more vulnerable to soil and groundwater pollution as precipitation pH shifts to acidic condition.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.24-31
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• 2004

A cold mix asphalt (CMA) treatment process was proposed as a tool to recycle soils contaminated with petroleum hydrocarbons. Experimental studies were conducted to characterize performances of the CMA process in treating soils contaminated with diesel or diesel compounds. From the screening experiments, it was found that performances of five types of asphalt emulsions that contained a cationic or an anionic or a nonionic surfactant were not substantially different. In consideration of higher affinity for soils and higher sorption coefficients obtained, an emulsion containing Lauryl Dimethyl Benzyl Ammonium Chloride (LDBAC) was selected as a promising asphalt emulsion for treating diesel-contaminated soils. When the asphalt emulsion LDBAC was applied to treat three compounds that originated from diesel, the removal efficiencies obtained in the order of decreasing efficiencies were as follows: docosane > pentadecane > undecane. Leaching experiments on the specimen formulated by the emulsion LDBAC found that the selected treatment method could treat soils with diesel concentrations as high as 10,000 mg/kg. Leaching of the diesel from the specimen was controlled by diffusion for the first four days and then leaching rate diminished substantially. The latter behavior was characterized as depletion, which represents that the contaminant released amounts to more than $50\%$ of the total amount of the contaminant that can be leached. The amounts of three diesel compounds leached from the specimen in the order of decreasing amount were undecane, pentadecane, and docosane. The curing of the soil contaminated with pentadecane was relatively slow.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.45-49
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• 2010

Research on nitrate-nitrogen ($NO_3-N$) leaching in turfgrass indicates that in most cases leaching poses minimal risk to the environment. Although there have been many studies investigating $NO_3-N$ leaching, there has been little research to investigate the effect of compaction level and rootzone mix on nitrogen (N) leaching. The research objective is to determine the effect of compaction level and rootzone mix on nitrogen leaching. The four rootzone mixes are 76.0:24.0, 80.8:19.2, 87.0:13.0 and 93.7:6.3 % (sand:soil). The four levels of compaction energies are 1.6, 3.0, 6.1, and 9.1 J $cm^{-2}$. Nitrogen was applied using urea at a rate of 147 kg $ha^{-1}$ split among three applications. Rootzone was packed into a polyvinylchloride pipe with a perforated bottom to facilitate drainage. Rootzone depth was 30 cm over a 5 cm gravel layer. Each column was sodded with Poa pratensis L. Hoagland solution designed for coolseason grasses, minus N, was used to ensure adequate nutrition in the rootzone. Turf grass quality and clipping yield were recorded from each tube at two-week intervals. The clippings were oven-dried at a temperature of $67^{\circ}C$ for 24 h and weighed. At the end of the study, root dry weight was determined by washing and oven-drying samples at $67^{\circ}C$ for 24 h. Leachate solution was collected weekly for analysis. More than 6.1 J $cm^{-2}$ of compaction energy increased possibilities of surface runoff. The compaction energy between 3.0 and 6.1 J $cm^{-2}$ produced more clipping dry weight and less N leaching than 9.1 J $cm^{-2}$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.49-50
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• 2014

Dredged sea soil contains various contaminants. First priority to recycle dredged sea soil is to pretreat it to remove various contaminants because recycling dredge sea soil without any pre-treatment may cause a secondary contamination due to the leaching of hazardous chemicals. In this study, pretreated dredged sea soil was used to investigate pozzolanic activity. The properties of pretreated dredged sea soil were investigated, the method for heat treatment was determined, and the compressive strength of mortar using dredged sea soil was examined to evaluate pozzolanic activity. According to the results, pretreated dredged sea soil has some possibility to work as a pozzolanic material. When dredged sea soil was heat treated for 90min at 550℃, compressive strength was shown to be comparable to that of plain cement mortar.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.3
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• pp.457-466
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• 2018

Objective: The present study aimed to assess the nitrogen (N) use efficiency of acidified pig slurry for regrowth yield and its environmental impacts on perennial ryegrass swards. Methods: The pH of digested pig slurry was adjusted to 5.0 or 7.0 by the addition of sulfuric acid and untreated as a control. The pig slurry urea of each treatment was labeled with $^{15}N$ urea and applied at a rate of 200 kg N/ha immediately after cutting. Soil and herbage samples were collected at 7, 14, and 56 d of regrowth. The flux of pig slurry-N to regrowth yield and soil N mineralization were analyzed, and N losses via $NH_3$, $N_2O$ emission and $NO_3{^-}$ leaching were also estimated. Results: The pH level of the applied slurry did not have a significant effect on herbage yield or N content of herbage at the end of regrowth, whereas the amount of N derived from pig slurry urea (NdfSU) was higher in both herbage and soils in pH-controlled plots. The $NH_4{^+}-N$ content and the amount of N derived from slurry urea into soil $NH_4{^+}$ fraction ($NdfSU-NH_4{^+}$) was significantly higher in in the pH 5 plot, whereas $NO_3{^-}$ and $NdfSU-NO_3{^-}$ were lower than in control plots over the entire regrowth period. Nitrification of $NH_4{^+}-N$ was delayed in soil amended with acidified slurry. Compared to non-pH-controlled pig slurry (i.e. control plots), application of acidified slurry reduced $NH_3$ emissions by 78.1%, $N_2O$ emissions by 78.9% and $NO_3{^-}$ leaching by 17.81% over the course of the experiment. Conclusion: Our results suggest that pig slurry acidification may represent an effective means of minimizing hazardous environmental impacts without depressing regrowth yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.4
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• pp.331-340
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• 2008

This study was conducted to investigate the effects of the type of swine manure on herbage productivity, the properties of soil and environmental pollution in mixed grassland. The field experiment was carried out on Livestock Breeding Station, Chonbuk in Korea from Nov. 2002 to Nov. 2005. Experimental plots were consisted of the types of swine manure, such as additional swine manure fermented with sawdust (SMFWS)+urea 50% and swine slurry (SS)+urea 50%. And then, chemical fertilizer (Urea) is used as control. DM yields of herbage were not different between chemical fertilizer and the type of swine manure. Feed values (CP, NDF, ADF, TDN) were not different between chemical fertilizer and swine manure treatments. After finishing with the experiment, Organic matter contents in soil increased. Organic matter, available phosphorous and Ca contents in swine manure treatment were higher than those of chemical fertilizer (p<0.05). $NO_3$-N and $NH_4$-N concentrations in leaching water in the mixed grassland was hardly influenced by application of swine manure and urea, whereas $NO_3$-N and $NO_3$-N levels in leaching water were less than 5 ppm.