• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.153-160
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• 2005

There have been large areas of soil contaminated with high levels of explosives. For this experimental work, 2,4,6-trinitrotoluene (TNT) was tested as a representative explosive contaminant of concern in both aqueous and soil samples and its removal was evaluated using three different chemical treatment methods: 1) the classical Fenton reaction which utilizes hydrogen peroxide ($H_2O_2$) and soluble iron at pH less than 3; 2) a modified Fenton reaction which utilizes chelating agents, $H_2O_2$, and soluble iron at pH 7; and 3) a Fenton-like process which utilizes iron minerals instead of soluble iron and $H_2O_2$, generating a hydroxyl radical. Using classic Fenton reaction, 93% of TNT was removed in 20 h at pH 3 (soil spiked with 300 mg/L of TNT, 3% $H_2O_2$ and 1mM Fe(III)), whereas 21% removed at pH 7. The modified Fenton reaction, using nitrilotriacetic acid (NTA), oxalate, ethylenediaminetetraacetic acid (EDTA), acetate and citrate as representative chelating agents, was tested with 3% $H_2O_2$ at pH 7 for 24 h. Results showed the TNT removal in the order of NTA, EDTA, oxalate, citrate and acetate, with the removal efficiency of 87%, 71%, 64%, 46%, and 37%, respectively, suggesting NTA as the most effective chelating agent. The Fenton-like reaction was performed with water contaminated with 100 mg/L TNT and soil contaminated with 300 mg/L TNT, respectively, using 3% $H_2O_2$ and such iron minerals as goethite, magnetite, and hematite. In the goethite-water system, 33% of TNT was removed at pH 3 whereas 28% removed at pH 7. In the magnetite-water system, 40% of TNT was removed at pH 3 whereas 36% removed at pH 7. In the hematite-water system, 40% of TNT was removed at pH 3 whereas 34% removed at pH 7. For further experiments combining the modified Fenton reaction with the Fenton-like reaction, NTA, EDTA, and oxalate were selected with the natural iron minerals, magnetite and hematite at pH 7, based on the results from the modified Fenton reaction. As results, in case magnetite was used, 79%, 59%, and 14% of TNT was removed when NTA, oxalate, and EDTA used, respectively, whereas 73%, 25%, and 19% removed in case of hematite, when NTA, oxalate, and EDTA used, respectively.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.19-32
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• 2002

This study is objected to identify the relations between surface- and shallow ground-water and the seasonal variation of their qualities in watersheds near Muju area. The water type shows mainly Ca-$HCO_3$type. Heavy-metal contamination of surface water is locally detected, due to the mixing with mine drainage. In October nitrate concentration is especially high in densely populated area. Cluster Analysis and Principal Component Analysis are implemented to interpret the complexity of the chemical variation of surface- and ground-water with large amount of chemical data. Based on the cluster analysis, surface-water was divided into five groups and ground-water into three groups. Principal Component Analysis efficiently supports the result of cluster analysis, allowing the identification of three main factors controlling the water quality. There are (1) hydrogeochemical factor, (2) anthropogenic factor and (3) heavy metal contaminated by mine drainage.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.02a
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• pp.29-48
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• 2001

일반적인 폐수처리 시 여러 광물들이 사용되는 데 예를 들면, 수산화칼슘 및 탄산나트륨은 중화제, 점토는 응집제, 알룸(alum) 및 염화철은 인 제거제로 사용되고 있다. 산성광산배수인 경우에는 알칼리성의 중화제로 석회 (CaO), 석회석 (CaCO$_3$), 가성소다 (NaOH), 탄산나트륨 (NaCO$_3$) 등이 사용된다. 그러나, 설비비 및 유지비가 많이 들어 몇 십년 동안 계속해서 침출되는 산성광산배수를 처리하기에는 문제가 있다. 산성광산배수 (Acid Mine Drainage, AMD)는 pH가 6.0 미만이고 총산도 (totalacidity)가 총알카리도 (total alkalinity)를 초과하는 물로서 노천광이 가행되었던 지역, 가행중이거나 휴광 또는 폐광된 광산에서 유출된다. 또한 도로사면 절개부나 지하철 터널에서도 황철석(pyrite)이나 백철석 (marcasite)을 함유하는 층이 공기 중에 노출되면 산성수가 침출되어 나오기도 한다. 산성광산배수에 의한 하천수의 오염이 매우 극심하여 때로는 미생물마저도 그 속에 살 수 없게 된다. 산성광산배수에 의해 오염된 하천수의 오염범위는 산성수의 양, 농도, 하천에 유입되는 산성수의 분포, 상류에서 흘러드는 오염되지 않은 물의 양, 지류에서 유입되는 물의 양에 따라 좌우된다. 산성광산배수 오염이 문제시되고 있는 나라는 미국을 포함하여 호주, 일본, 한국, 러시아, 남아연방 등이다. 산성광산배수는 환원환경에서 생성된 석탄층 및 접촉교대 또는 열수에 의해 생성된 금속광이 공기 및 물에 노출되어 생성되는 자연적인 현상이다. 그러나 국지적인 지역에서 인간이 이 광상들을 환경영향을 고려하지 않고 대규모로 개발할 때 인간 생활에 심각한 영향을 미치는 것이다. 광산산성배수를 처리하기 위해 상기와 같이 여러 기술이 도입 적용되었으며 일부 기술들은 현재도 사용되고 있다. 각 기술마다 일장일단이 있으므로 경비의 과다, 유지 및 관리에 대한 지속성 여부, 공간의 확보 여부, 지역적 특수성에 맞춰 가장 적합한 방법을 채택하여야 하며 꾸준히 채택한 기술의 개량 및 새로운 기술의 첨가가 요구되고 있다. 따라서, 산성광산배수 오염지대에 대해 획일적으로 같은 처리방법을 채택하여 사용하는 것보다 각 지역 또는 광산산성폐수가 유출되어 나오는 광산폐기물의 특성 등을 고려하여 거기에 맞는 기술들을 복합적으로 또는 단독으로 사용하되 처리방법 채택 시 신중을 기할 것이 요망된다.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.55-64
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• 2008

A detailed understanding and appreciation of the important mechanisms operating at the soil:root interface, commonly identified as the rhizosphere, is critical for evaluating the potential for particular plant species to be successfully used as part of a phytoremediation technique. For specific plants, mechanisms may exist to overcome the inherit limitation of the phytoremediation technique when poorly mobile soil metals are of interest. In the present study, the influence of root exudates on the rhizosphere chemistry of soil and consequential metal uptake were investigated following culture of vetiver grass (Vetiveria zizanioides), recognized as a promising plant for land stabilization, in three different long-term contaminated soils and one non-contaminated control soil. The soil solution pH increased (0.3-1.1 units) following vetiver grass culture and dissolved organic carbon (DOC) also significantly increased in all soils with the highest increase in PP02 (23 to $173mg\;L^{-1}$). Chemical changes are contributed to root exudation by vetiver grass when exposed to high concentration of heavy metals. Chemical changes, consequently, influenced metal (Cd, Cu, Pb, and Zn) solubility and speciation in the rhizosphere. The highest solubility was observed for soil Ko01 (eg. 2091 and $318{\mu}g\;L^{-1}$ for Cd and Pb, respectively). Initial heavy metal solubility in soils varied with soil and either increased or decreased following vetiver grass culture depending on the soil type. An increase in pH following plant culture generally resulted in a decrease in metal solubility, while elevated DOC due to root exudation resulted in an increase in metal solubility via the formation of metal-DOC complexes. Donnan speciation demonstrated a significant decrease in free Cd and Zn in the rhizosphere and the concentration of Cd, Pb, and Zn in vetiver grass shoot was highly correlated with soluble concentration rather than total soil metal concentration.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.180-185
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• 2017

Restoration of min-impacted arable land is often performed through stabilization of trace elements by amendment treatment combined with (clean) soil covering on the surface. Recently, soil loss problem from sloping remediated agricultural lands has risen as an emerging concern. In this study, efficacy of aggregation formation was assessed by single and binary treatments of four potential amendments (bentonite, lime, organic matter, and steel slag) applied on three cover soils having different clay contents (9.4, 14.7, and 21.2% for A, B, and C soils respectively). In results of single treatments, 5% organic matter for A soil and 5% lime for B and C soils were found most effective for the aggregation formation compared to the respective controls (without amendments). Among nine binary treatments, 3% organic matter + 1% lime for A soil and 1% organic matter + 3% lime for both B and C soils led to the highest formation of aggregation (30.4, 25.0, and 36.5% for A, B, and C soils). For a site-application, the soil erodibility difference between the cover soils (0.045, 0.051, and 0.054 for A, B, and C soils, respectively) and the national average of arable land (0.032) was assumed to be compensated by amendment addition, which is equivalent to 29.1% aggregation formation. To achieve the aggregation goal, 5% lime for A and B soils and 3% lime for C soil were best in the consideration of benefit/cost, thereby effectively and economically reducing soil loss from sloping remediation site. Soil alkalinity induced by lime treatment was not considered in this work.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.3
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• pp.37-44
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• 2020

The Project supporting organic fertilizer started in 1999 as a national policy. In farmhouse, over application of mixed organic compound fertilizer(OC) caused salt accumulation in plastic film house soil. To replace inorganic fertilizer with OC fertilizer, this study was investigated the effect of OC application on yield and soil chemical properties for lettuce cultivation in plastic film house. The OC fertilizer was applied at 50(OC50+N50), 100(OC100), and 150(OC150) % level of the basal amount of nitrogen fertilizer in soil testing recommendation. And these were compared to NPK(nitrogen, phosphat, and potash fertilizer) and PK treatment. The yield of lettuce in OC100 was similar to that of NPK treatment. In OC 50, 100 and 150 treatments, pH had a tendency to increase than that of NPK treatment. Nitrate nitrogen(NO₃-N) and electrical conductivity(EC) were similar to NPK treatment. These showed that nutrients from OC fertilizer were less likely to accumulate in soil than NPK. Also, use efficiency of nitrogen in OC100 treatment were similar to NPK treatment. These results suggest that OC application as the basal dressing at the 100% level could be best to prevent a nutrient accumulation of soil and to increase the yield and commercial quality for lettuce.

• Journal of Soil and Groundwater Environment
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• v.16 no.4
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• pp.31-37
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• 2011

The feasibility study of soil flushing was investigated to remediate lubricant oil and zinc contaminated railway soil. In this study, mixed washing agents of surfactant and inorganic acid/base were used for the simultaneous removal. The mixed washing agent of non-ionic surfactant and HCl removed 15% of the lubricant oil and 40% of zinc, respectively. Alkaline-enhanced soil washing process increased the removal of lubricant oil up to 40%. This is because alkaline solution reduced the interfacial tension between water phase and lubricant oil phase due to the soap formation reaction. To simulate in-situ soil flushing for the remediation of railroad-related contamination, two dimensional soil flushing was carried out based on the results of batch soil washing. In the soil flushing, the removal efficiencies of lubricant oil and zinc were 34% and 16%, respectively. Even though the removal efficiency was low, the mixed washing agent can remove metal and lubricant oil simultaneously.

• Journal of Soil and Groundwater Environment
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• v.22 no.2
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• pp.33-40
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• 2017

In typical remediation practices, separate washing systems have to be applied to clean up the soils contaminated with both oil and heavy metals. In this study, we evaluated the efficiency of successive two-stage soil washing in removal of mixed-contaminants from soil matrix. Two-stage soil washing experiments were conducted using different combinations of chemical agent: 1) persulfate oxidation, followed by organic acid washing, and 2) Fenton oxidation, followed by inorganic acid washing. Persulfate oxidation-organic acid washing efficiently removed both organic and inorganic contaminants to meet the regulatory soil quality standard. The average removal rates of total petroleum hydrocarbons (TPH), Cu, Pb, and Zn were 88.9%, 82.2%, 77.5%, and 66.3% respectively, (S/L 1:10, reaction time 1 h, persulfate 0.5 M, persulfate:activator 3:1, citric acid 2 M). Fenton oxidation-inorganic acid washing also gave satisfactory performances to give 89%, 80.9%, 87.1%, and 67.7% removal of TPH, Cu, Pb, and Zn, respectively (S/L 1:10, reaction time 1 hr, hydrogen peroxide 0.3 M, hydrogen peroxide:activator 5:1, inorganic acid 1 M).

• Korean Journal of Organic Agriculture
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• v.18 no.3
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• pp.363-375
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• 2010

Sustainable farming systems have remarkably increased in Korea due to the increase of environmental concerns caused by the conventional systems. This study was performed on eight-year-old 'Niitaka' pear tree s to investigate the effects of different organic fertilizers on soil chemical and microbial properties and leaf and bud developments. Treatment and applications included 10 kg of rice bran (RB), 10 kg of coffee bran compost (CBC), 10 kg of Chitin incubated compost (Micro keeper$keeper^{(R)}$, CIC), and 30 kg of the mixture of the RB, CBC, and CIC (RCC). Control received 60 g of NPK (16-11-12) chemical fertilizer. The organic fertilizers increased organic matter, nutrient concentrations such as P, K, Ca, and Mg, and microbial biomass in soils compared to the control. RCC had the greatest specific leaf weight (SLW), and the other treatments did not have a significant difference for the SL W. Leaf P and K concentrations were different among the treatments, but they were not affected by the amounts of the soil nutrients. No differences were observed in the leaf Ca and Mg concentrations in the treatments. Organic fertilizers had greater chlorophyll contents than the control but had similar flower bud characteristics to the control.

• Journal of Soil and Groundwater Environment
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• v.10 no.2
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• pp.35-43
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• 2005

Bioslurping combines the three remedial approaches of bioventing, vacuum-enhanced free-product recovery, and soil vapor extraction. Bioslurping is less effective in tight (low-permeability) soils. The greatest limitation to air permeability is excessive soil moisture. Optimum soil moisture is very soil-specific. Too much moisture can reduce air permeability of the soil and decrease its oxygen transfer capability. Too little moisture will inhibit microbial activity. So Modified Fenton reaction as chemical treatment which can overcome the weakness of Bioslurping was experimented for simultaneous treatment. Although the diesel removal efficiency of SVE process increased in proportion to applied vacuum pressure, SVE process was difficulty to remediation quickly semi- or non-volatile compounds absorbed soil strongly. And SVE process had variation of efficiency with distance from the extraction well and depth a air flow form of hemisphere centering around the well. Below 0.1 % hydrogen peroxide shows the potential of using hydrogen peroxide as oxygen source but the co-oxidation of chemical and biological treatment was impossible because of the low efficiency of Modified Fenton reaction at 0.1 % (wt) hydrogen peroxide. NTA was more efficiency than EDTA as chelating agent and diesel removal efficiency of Modified Fenton reaction increased in proportion to hydrogen peroxide concentration. Hexadecane as typical aliphatic compound was removed less than Toluene as aromatic compound because of its structural stability in Modified Fenton reaction. What minimum 10% hydrogen peroxide concentration has good remediation efficiency of diesel contaminated groundwater may show the potential use of Modified Fenton reaction after bioslurping treatment.