• Title/Summary/Keyword: leaching characteristics

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Evaluation of Pretreatment Moisture Content and Fixation Characteristics of Treated Wood for Pressure Treatment of Japanese Red Pine and Japanese Larch Skin Timber with ACQ, CUAZ and CuHDO (소나무와 낙엽송 스킨팀버의 ACQ, CUAZ, CuHDO 가압처리를 위한 처리용 목재의 적정 함수율 및 처리목재의 정착 특성 평가)

  • Choi, Yong-Seok;Oh, Se-Min;Kim, Gyu-Hyeok
    • Journal of the Korean Wood Science and Technology
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    • v.39 no.6
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    • pp.481-489
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    • 2011
  • This study was conducted to evaluate the pressure treatment characteristics of Japanese red pine and Japanese larch skin timber with ACQ-2, CUAZ-2 and CuHDO-1. The effect of moisture content (MC) on preservative treatability was investigated for Japanese red pine sapwood and Japanese larch heartwood, and fixation characteristics of CCA alternatives was also evaluated. Japanese red pine sapwood, which was dried below 30 percent MC, was fully penetrated with preservatives, and minimum requirement of preservative retention for the hazard class H3 was achieved. Through measuring preservative retention gradient in Japanese red pine sapwood, it was confirmed that the retention gradient of CuHDO-1 was steeper than that of both ACQ-2 and CUAZ-2. In particular, it was intensified at a higher MCs of wood samples (25∼30%). Japanese larch heartwood did not meet the minimum requirement of penetration and retention for the hazard class H3 over the range of pretreatment MCs tested. With presteaming under $121^{\circ}C$ for 12 hours, the treatability of Japanese larch heartwood was enhanced to meet the minimum requirement for the hazard class H3. The fixation rate of copper was much more faster under drying condition compared with nondrying condition; more than 95% of copper were fixed in 3~6 days and 1 day under drying conditions in Japanese red pine sapwood and Japanese larch heartwood, respectively. After 3-week fixation period at ambient temperature, the amount of mobile copper in treated wood sample that remains available for leaching from treated wood was the highest in the wood samples treated with ACQ-2, followed by CuHDO-1 and CUAZ-2. It was proportional to the amount of copper in treating solution.

Variations of Clay Mineral Assemblage, Colour, and Microfossil Abundance in the Tertiary Sediments from the Pohang Area During Chemical Weathering (포항지역(浦項地域) 제(第)3기층(紀層) 퇴적암(堆積岩)중 화학적풍화작용(化學的風化作用)이 결토광물조성(結土鑛物組成), 화학조성(化學組成), 암색(岩色) 및 미화석(微化石) 산출빈도(産出頻度)에 미치는 영향)

  • Moon, Hi-Soo;Yun, Hyesu;Min, Kyung Duck;Lee, Hyun Koo;Lee, Jong Chun
    • Economic and Environmental Geology
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    • v.23 no.2
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    • pp.201-213
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    • 1990
  • Mineralogy, chemistry, physical property, and fossil abundance have been studied for the samples collected from three weathering profiles, two from the Duho Formation and one from the Hagjeon Formation in the Tertiary sediments in the Pohang area. The mineralogy of the samples from the Duho Formation shows somewhat different from that of the Hagjeon Formation. Kaolinite is more abundant and shows higher crystallinity in samples from the Duho Formation than those in the Hagjeon Formation, but clay mineral assemblage in each weathering profile remain fairly constant with depth. This difference in mineral distribution seems to be inherited from original source materials. It indicates that little or not severe leaching has been taking place in these three weathering profiles. Weathering indicies indicate different degrees of susceptibility to chemical weathering in these two formations. The Duho Formation has a higher degree of susceptibility to weathering than that of the Hagjeon Formation which is mainly due to differences in clay mineral assemblages in both formations. A noticeble colour difference between oxidized and unoxidized zones in each profile can be easily recognized which is definetely due to different decomposition rate organic carbon by various oxidation state from surface to bottom of the profile. Weathering process have also intensively influenced microfossil preservation about up to 7-10 m in depth in the Duho Formation. Consequently, characteristics observed at weathering surface should be used as a subsidiary tool in setting geologic boundary or establishing formation. Great care must be taken to choose sampling site for microfossil study.

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Characterization of Heavy Metal-enriched Particles from Contaminated Soils in a Military Shooting Range (군사격장 오염토양 내 고농도 중금속함유 입자의 기초특성연구)

  • Kim, Jeeeun;Kim, Jeongjin;Bae, Bumhan;Kim, Younghun
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.11
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    • pp.25-31
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    • 2013
  • Civil and military firing ranges are usually contaminated with heavy metals such as lead and copper and remediation is required. Acid washing and extraction are common remediation methods. Lead contaminated firing range soil samples were collected and a preliminary study was conducted to evaluate the characteristics of the contamination and the contribution of high specific gravity particles. Ethylenediamine tetra acetic acid(EDTA) extraction was applied for the removal of heavy metal but the extraction was not feasible for the firing range soil. Even after the repeated EDTA extraction, the contamination were still over the Korean environmental standard indicating that soil particles highly contaminated with heavy metal which release the heavy metal ion even after the repeated extraction. Some colored and higher specific gravity particles were separated from the soil samples and analyzed. The colored particles have specific gravity of 2.5-6.6. The saturation ratio of Pb and EDTA was 4.9-32%. After removal of these colored particles, the sandy soil showed moderate contamination which can be treated with soil washing. This was proved with the five-level sequential extraction and TCLP tests.

A Study on the Horizontal and Vertical Distribution of Heavy Metal Elements in Slime Dump from Dukum Mines, Korea (덕음광산 선광광미와 주변토양의 중금속에 대한 수평.수직적인 분산에 관한 연구)

  • 박영석
    • Economic and Environmental Geology
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    • v.33 no.2
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    • pp.91-100
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    • 2000
  • It has been more than ten years since Dukun mine was abandoned. Tailings of waste deposits and slime dumps in the abandoned Dukum mine have been left to be deserted for fifty years. The results of fifty years of neglecting are nothing short of major environmental problems. Slime dumps have been exposed to air and water in the mine over ten years and then soil profile has been formed well. Soil in the upper layer (A horizon) is the light gray color due to the leaching of cations. Soil in the lower layer (A2 horizon, 0.2∼0.3m)is tinted with reddish brown and yellowish brown color due to the development of iron oxides and iron hydroxides. Soil in the lower part of B horizon of (1.0∼3.0m) with the growth of copper and zinc oxides exposes to the bluish green, light blue, and dark gray. Ranging from 3m to 8m in depth, 85 samples were taken from 22 sampling sites with 50m intervals located on the slime dump area with hand auger and trench (open cut). As tailings was distributed, heavy metal elements extracted by the process of surface water and ground water move and disperse in to the hydrosphere. Waste dumps were distributed in and around the mine and water draining from those dumps be a potential source of contamination. Soils, thus, can be dispersed into downslope and downstream through wind and water by clastic movement. These materials may be deposited in another horizon if the water is withdrawn, or if the materials are precipitated as a result of differences in pH, or other conditions in deeper horizons. These were primarily associated with acid mine drainage. The characteristics and rate of release of acid mine drainage are influenced by various chemical and biological reactions at the source of acid generations. Prolonged extration of heavy metal elements has a detrimental effect on the agricultural land and residental area. Twenty soil samples were collected from the agricultural land in the area (0∼30 cm). Seventeen samples were also taken from the sediment in the stream running alongside the dumps. The dispersion patterns of heavy metal elements are as follows: The content of As ranged 2∼6 ppm in a horizon, 20∼125 ppm in B horizon with large amount of clay mineral is concentrated and the content of Cd ranged 1∼2 ppm in A horizon, 4∼22 ppm in B horizon. Like Cd, the content of As, Cu, Zn, Pb in B horizon is higher than that in A horizon (approximately 5∼100 times). When soil formation proceeds in stages, it is necessary to investicate the B horizon with the concentration of heavy metal and preventive measures will have to established.

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Correlation of $^{137}Cs/^{60}Co$ Activity Ratio in Radwaste with Primary Coolant (원자로 냉각재와 방사성폐기물 내 $^{137}Cs/^{60}Co$ 핵종비)

  • Jee, Kwang-Yong;Park, Yeong-Jae;Pyo, Hyung-Yeol;Ahn, Hong-Joo;Kim, Won-Ho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.1
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    • pp.9-17
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    • 2007
  • In order to compare the correlation of radioactivity ratio between the radwaste streams and the primary coolant of PWR NPPs, A RCS sampling kit was installed to primary coolant system for the collection of the radionuclides during the normal operation of NPPs. RCS samples were collected from PWR type of domestic NPPs through 2004 to 2005, and pretreated with acid microwave digestion or leaching method to assay quantitatively of several interesting radionuclides. The radioactivity ratios of $^{137}Cs\;to\;^{60}Co$ in a filter cartridge and a resin cartridge were 2.3E-2 and 7.3E-1, respectively. At a same period of the reactor operating cycle, the radioactivity ratios of $^{137}Cs\;to\;^{60}Co$ were 6.3E-1 for a evaporator bottom, 6.7E-1 for a spent resin, and 5.6E-2 for a dry active waste, so that these radwaste streams were identified as having similar characteristics with the corresponding RCS samples.

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Characterization of Cement Waste Form for Final Disposal of Decommissioned Concrete Waste (해체 콘크리트 폐기물 최종처분을 위한 시멘트 고화체 특성 평가)

  • Lee, Yoon Ji;Hwang, Doo Seong;Lee, Ki Won;Jeong, Gyeong Hwan;Moon, Jei Kwon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.11 no.4
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    • pp.271-280
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    • 2013
  • Since the decommissioning of nuclear plants and facilities, large quantities of slightly contaminated concrete waste have been generated. In Korea, the decontamination and decommissioning of the KRR-1, 2 at the KAERI have been under way. And concrete waste was generated about 800 drums of 200 L. The conditioning of concrete waste is needed for final disposal. The concrete waste is conditioned as follows: mortar using coarse and fine aggregates is filled void space after concrete rubble pre-placement into 200 L drum. Thus, this research has developed an optimizing mixing ratio of concrete waste, water, and cement and has evaluated characteristics of a cement waste form to meet the requirements specified in disposal site specific waste acceptance criteria. The results obtained from compressive strength test, leaching test, thermal cycling test of cement waste forms conclude that the concrete waste, water, and cement have been suggested to have 75:15:10wt% as the optimized mixing ratio. Also, the compressive strength of cement waste form was satisfied that including fine powder up to maximum 40wt% in concrete debris wastes about 75%. As a result of scale-up test, the mixture of concrete waste, water, and cement is 75:10:15wt% meet the satisfied compressive strength because the free water increased with and increased in particle size.

The Physico chemical Characteristic of MSW and sludge in west area of Kangwondo (강원도 영서지역 생활폐기물 및 슬러지의 물리·화학적 특성에 관한 연구)

  • Lee, Geon-Joo
    • Journal of the Korea Organic Resources Recycling Association
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    • v.12 no.4
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    • pp.112-120
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    • 2004
  • In this study, the physico chemical characteristic of MSW and sludge in west area of Kangwondo was investigated for database, managing the waste and waste treatment facility. The sampling sites were selected as 6 different MSW generation area and 2 sludge generation area. it is necessary to measure the characteristics of MSW to build the data-base. The year of 2000, 197.4ton/day of MSW which was generated in this area. This MSW was composed of 26.6% food wastes, 24.2% of papers, 22.8% of plastics & vinyls, 9.6% of textiles, 3.80% of wood, 2.8% of rubbers & leathers and others, respectively. Most of MSW are composed of food, paper and plastic waste and combustible waste is more than 89%. The generation of papers and vinyls are almost same for different seasons For 3-components of MSW, moisture is 40.2%, combustible component is 52.1% and ash is 7.7% and for 3-components of sludge, moisture is 83.3%, combustible component is 7.7% and ash is 9%. The chemical element has the high order of carbon(51.6%), oxygen(38.6%), hydrogen(7%) on the dry basis of wastes. And the high heating value of MSW is 4989.4 Kcal/kg sludge is 4428.04 Kcal/kg and low heating value of the MSW which is measured by calorimeter is 2032.88kcal/kg. From the leaching test of wastes, there is no heavy metals.

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Growth and yield responses of rice varieties to various soil water deficit conditions under different soil types

  • Kikuta, Mayumi;Samejima, Hiroaki;Magoti, Rahab;Kimani, John M.;Yamauchi, Akira;Makihara, Daigo
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.322-322
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    • 2017
  • To avoid drought stress under rainfed upland conditions, it is important for rice to efficiently utilize water at shallow soil layers supplied by rainfall, and access to water retained in deer soil layers. The root developmental characteristics of rice, which play important role in the adaptability to drought conditions, vary depending on the variety. Moreover, water availability for plant differs depending on the soil types that have different physical properties such as water holding capacity, permeability, capillary force, penetration resistance, etc. In this study, we evaluated growth and yield responses of rice varieties to various soil water deficit conditions under three different soil types. The experiment was conducted in a plastic greenhouse at the Kenya Agricultural and Livestock Research Organization-Mwea from October 2016 to January 2017. Two upland varieties (NERICA 1 and 4) and one lowland variety (Komboka) were grown in handmade PVC pots (15.2 cm diameter and 85.0 cm height) filled with three different types of soil collected from major rice-growing areas of the country, namely black cotton (BC), red clay (RC), and sandy clay (SC). Three watering methods, 1) supplying water only from the soil surface (W1), 2) supplying water only from the bottom of the pots (W2), and 3) supplying water both from the soil surface and the bottom of pots (W3), were imposed from 40 days after sowing to maturity. Soil water content (SWC) at 20, 40, and 60 cm depths was measured regularly. At the harvesting stage, aboveground and root samples were collected to determine total dry weight (TDW), grain yield, and root length at 0-20, 20-40, 40-60, and 60-80 cm soil layers. Irrespective of the watering methods, the greatest root development was obtained in RC, while that in BC was less than other two soils. In BC, the degree of yield reduction under W1 was less than that in RC and SC, which could be attributed to the higher water holding capacity of BC. In RC, the growth and yield reduction observed in all varieties under W1 was attributed to the severe drought stress. On the other hand, under W2, SWC at the shallow soil depth in RC was maintained because of its higher capillary force compared with BC and SC. As the result, growths and yields in RC were not suppressed under W2. In SC, deep root development was not promoted by W2 irrespective of the varieties, which resulted in significant yield losses. Under W1, the rice growth and yield in SC was decreased although shallow root development was enhanced, and the stomatal conductance was maintained higher than RC. It was suspected that W1 caused nutrients leaching in SC because of its higher permeability. Under rainfed conditions, growth and yield of rice can be strongly affected by soil types because dynamics of soil water conditions change according to soil physical properties.

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Evaluation and Improvement Measures on collection and transportation System of Food Waste (음식물 쓰레기 수집운반체계 평가 및 개선 방안)

  • Lee, Hyun-Hee;Ryu, Ji-Young;Shin, Dae-Yewn;Phae, Chae-Gun
    • Journal of the Korea Organic Resources Recycling Association
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    • v.12 no.2
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    • pp.110-120
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    • 2004
  • This research sought to analyze the food waste collection and transportation system in Korea's related public resource-making facilities, address related problems, and suggest a reasonable alternative measure. For the food waste sorting-out and discharging methods, apartments and similar housings use containers, and individual-style housings use 'quantity-proportional' bags. The sorting and discharging methods should be improved to boost the reuse of resource-made output. The analysis of collection and transportation costs by local governments indicates that they range from 30,000 won to 150,000 won per ton, varying greatly by characteristics of local governments, thus suggesting a need to establish costs calculation criteria to justify the costs. Charges imposed to each household were not greatly problematic in the case of quantity-proportional bags; however, in the case of apartments and similar housings, charges varied greatly, suggesting a need to impose differentiated charges calculated on the basis of collection and transportation costs according to regions. Many places used household-garbage collection vehicles to collect food waste, raising the possibility of causing complaints on leaching water and bad odors. Thus, exclusive food waste collection vehicles should be gradually introduced. Also, in certain places, vehicles should travel more than 20km to collect food waste, and in such cases, a cargo transferring system should be introduced to boost efficiency in carriage.

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Effects of Lime, Magnesium Sulfate, and Compound Fertilizers on Soil Chemical Properties of Acidified Forest Soils (산성화(酸性化)된 산림토양(山林土壤)에 석회(石灰), 황산고토(黃酸苦土) 및 복합비료(複合肥料) 시비(施肥)가 토양(土壤)의 화학적(化學的) 성질(性質)에 미치는 영향(影響))

  • Yoo, Jeong-Hwan;Byun, Jae-Kyoung;Kim, Choonsig;Lee, Choong Hwa;Kim, Young-Kul;Lee, Won-Kyu
    • Journal of Korean Society of Forest Science
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    • v.87 no.3
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    • pp.341-346
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    • 1998
  • The effects of CaO, $CaO+MgSO_4$, and $CaO+MgSO_4$+compound fertilizers(NPK) on soil chemical properties of acidified forest soils were studied in Quercus spp. and Pinus rigida stands in Mt. Namsan and Mt. Surak in urban areas, and Kwangnung in a mountain area. The soil samples were collected in November 1995 after every year fertilization from November 1991 through April 1995. The fertilizations affected soil chemical properties. Soil pH increased after fertilizations compared with control. However, the effect was different between the stand types and the areas. Organic matter and total nitrogen content were not changed, while exchangable cations such as calcium and magnesium increased after fertilizations. However, these ration concentrations after fertilizer treatments were lower in P. rigida than in Quercus spp. stands. These rations also showed increased leaching characteristics more in the urban area than in the mountain area.

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