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Application of Practical Immobilizing Agents for Declining Heavy Metal (loid)s Accumulation by Agricultural Crop (Allium wakegi Araki)

  • Seo, Byoung-Hwan;Kim, Hyun-Uk;Lwin, Chaw Su;Kim, Hyuck Soo;Kim, Kwon-Rae
    • Korean Journal of Soil Science and Fertilizer
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    • v.50 no.4
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    • pp.226-234
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    • 2017
  • In order to reduce the accumulation of toxic metals (As, Cd and Pb) in the chives, various immobilizing agents such as a soil pH change-inducing immobilizing agent (lime), sorption agent (compost, spent mushroom compost), soil pH change and sorption agent (biochar) and, dissolved organic carbon (DOC) coagulator (gypsum) and uncontaminated soil were applied to the contaminated soils in isolation and in combination. Then chives were grown and determined for As, Cd and Pb concentrations accumulated in the edible part at harvest. The Cd and Pb concentrations of the chive plant grown in the contaminated soil (no treatment) exceeded the legislated Korean guideline values (Cd: $0.05mg\;kg^{-1}$, Pb $0.1mg\;kg^{-1}$) and As concentration ($21mg\;kg^{-1}$) was 1,000 times higher than chives plant grown in uncontaminated environment in Korea. Application of lime and gypsum significantly reduced As, Cd and Pb concentrations in all chives examined, due to the increased soil pH and decreased soil DOC. Also, application of combination treatments involving DOC coagulator such as gypsum together with lime decreased As, Cd and Pb concentrations from 21, 1.3 and $9.7mg\;kg^{-1}$ to 2.1, 0.1 and $1.1mg\;kg^{-1}$, respectively. Consequently, it was concluded that pH change-inducing immobilizing agent (lime) which was already well known and DOC coagulator such as gypsum could be used as a promising immobilizing agent for safer chives plant production.

The Difference Order Clustering for Multi-dimensional Entities (다차원 개체를 위한 차이등급 clustering)

  • Rhee, Chul;Kang, Suk-Ho
    • Journal of the Korean Operations Research and Management Science Society
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    • v.14 no.1
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    • pp.108-118
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    • 1989
  • The clustering problem for multi-dimensional entities is investigated. A heuristic method, which is named as Difference Order Clustering (DOC) is developed for the grouping of multi-dimensional entities DOC method has an advantage of identifying the bottle-neck entities. Comparisons among the proposed DOC method, modified rank order clustering (MODROC) method, and lexicographical rank order clustering using minimum spanning tree (lexico-MMSTROC) are illustrated by a part type selection problems.

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Influences of Water Level and Vegetation Presence on Spatial Distribution of DOC and Nitrate in Wetland Sediments (수심의 정도와 식생의 유무에 따른 인공습지 토양 내 유기탄소와 질산염의 공간적 분포)

  • Seo, Ju-Young;Song, Keun-Yea;Kang, Ho-Jeong
    • Journal of Wetlands Research
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    • v.12 no.2
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    • pp.59-65
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    • 2010
  • Wetlands are a well known ecosystem which have high spatial-temporal heterogeneity of chemical characteristics. This high heterogeneity induces diverse biogeochemical processes, such as aerobic decomposition, denitrification, and plant productivity in wetlands. Understanding the dynamics of dissolved organic carbon (DOC) and inorganic nitrogen in wetlands is important because DOC and inorganic nitrogen are main factors controlling biological processes in wetlands. In this study, we assessed spatial distribution of DOC and inorganic nitrogen with relation to the different hydrology and vegetation in created wetlands. Both DOC and nitrate contents were significantly higher in vegetated areas than open areas. Different water levels also affected DOC contents and their quality. Average DOC contents were $0.37mg{\cdot}g^{-1}$ in deep riparian (DR) and $0.31mg{\cdot}g^{-1}$ in shallow riparian (SR). These results appeared to be related to the interaction between carbon supply by vegetation and microbial decomposition. On the other hand, inorganic nitrogen contents were not affected by water level differences. This result indicates that presence/absence of vegetation could be a more important factor than hydrology in the spatial dynamics of inorganic nitrogen. In conclusion, we observed that vegetation and hydrology differences induced spatial distribution of carbon and nitrogen which are directly related to biogeochemical processes in wetlands.

Distributions and Sources of Dissolved Organic Matter in Seawaters Surrounding Aqua Farms on the Haengwon-ri in Jeju-Island in Summer 2015 (2015년 하계 제주 행원리 일대 양식장주변 해수 중 용존유기물 분포와 기원)

  • Kim, Jeonghyun;Kim, Tae-Hoon
    • Ocean and Polar Research
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    • v.39 no.1
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    • pp.35-43
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    • 2017
  • Concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved organic phosphate (DOP), and colored dissolved organic matter (CDOM) were measured in the coastal sea off inland aqua farms in northeastern Jeju Island in summer 2015. The highest concentrations of DOC, DON, and DOP were revealed in the surface water off Hado-ri where the lowest salinity conditions prevailed (31.6). The concentrations of DOC, DON, and DOP in the surface water were lower in the inner stations (SH1-1, 1-2, and 1-3) near the aqua farms of the Haengwon-ri than in the outer stations. The concentrations of DOC, DON, and DOP negatively correlated with salinity. These results indicate that the contribution of dissolved organic matter (DOM) from the aqua farms seems to be not significant. On the other hand, the higher concentrations of DON and DOP in the inner stations of Hado-ri (HD 1-1) seem to be attributed to excrement of migrating birds. The three components of CDOM (T, M, and C peaks) showed no relationship with salinity, perhaps due to various in situ productions by marine organisms and decomposition by ultraviolet radiation. The observed lower C:M ratio, an indicator of terrestrial source, and the higher biological index (BIX) of CDOM in the station off Hado-ri indicate that DOM is produced mainly by biological activity. Based on the higher humification index (HIX) of CDOM and the higher DOC:DON ratio off Haengwon-ri, refractory DOM in the inland aqua farms is likely transported to the coastal sea.

Characteristics of TOC Distribution in Lake Hapcheon (합천호의 TOC 분포 특성)

  • Seong, Jin-Uk;Kim, Hyung-Jin;Park, Jae-Chul
    • Journal of Environmental Science International
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    • v.20 no.6
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    • pp.711-719
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    • 2011
  • This study was conducted to estimate the distribution characteristics and budget of organic matter in the Lake Hapcheon. In the dry season, the concentration ranges of organic carbons were similar, but in the rainfall season, it showed about double concentrations. Changes of vertical water quality in the lake, there were no big differences with the concentration by the depth. However, it tends to be relatively high on the surface, a little low on the mid-depth and high in the lake bottom. DOC rate at TOC, it was lower than POC rate at inflow and DOC rate was higher than POC rate in the lake and discharging water. R-DOC accounted for more 80% of DOC rate in all investigated areas, therefore we judge that this R-DOC is to increase the organic carbon pollution gradually. As the result of the calculated organic carbon budget in the Lake Hapcheon, the amount of allochthonous, autochthonous and release were 3,552, 3,288, 228 tonC/year, respectively. the amount of discharge, decomposition and sedimentation were 504, 1,344, 5,520 tonC/year, respectively. According to this investigation, the changed amount of organic matter in the Lake Hapcheon recorded -300 tonC/year with the increase of 7,068 tonC/year and the decrease of 7,368 tonC/year.

An Experimental Study on Regeneration Characteristics by Variation of Exhaust Gas Temperature, HC and $O_2$ Concentrations on DOC-CDPF System (배기가스의 온도 및 HC와 $O_2$의 조성 변화에 따른 DOC-CDPF의 재생 특성에 관한 실험적 연구)

  • Cho, Yong-Seok;Lee, Seang-Wock;Lee, Jung-Sub;Yoon, Yu-Bin;Park, Young-Joon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.1
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    • pp.43-49
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    • 2009
  • A catalyzed diesel particulate filter (CDPF) causes the progressive increase in back pressure of an exhaust system due to the loading of soot particles. To minimize pressure drop which is generated by CDPF, the filter should be regenerated when it collects a certain quantity of soot. It is important to know characteristics of regeneration of CDPF with various of exhaust gas temperatures and compositions. The oxidation of HC in DOC leads to increase gas temperature of DOC downstream. The increased gas temperature by DOC has an positive effect on CDPF regeneration. This study presents characteristics of regeneration of CDPF with DOC according to various gas composition, such as HC and $O_2$ concentration. The test-rig is used to control each gas composition and temperature during regeneration of CDPF. Experimental results indicate that the increased concentration of $O_2$ regenerates DPF more actively. With increasing HC concentration, the gas temperature of CDPF upstream increased due to more oxidation of HC. But excessive supply of HC leads to decrease of $O_2$ concentration in the CDPF, which makes it hard to regenerate CDPF.

Variations of DOC and Phenolics in Pore-water of Peatlands (이탄습지 공극수내 용존유기탄소와 페놀계열 물질의 변화도)

  • Freeman, Chris;Kim, Seon-Young;Kang, Ho-Jeong
    • Korean Journal of Ecology and Environment
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    • v.35 no.4 s.100
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    • pp.306-311
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    • 2002
  • The amount and composition of dissolved organic carbon in wetlands are of great importance for their influence in secondary productivity, various biogeochemical processes, and aquatic ecosystem functions. In the present study, we measured variations of DOC and phenolics concentrations in pore-water of three northern peatlands (bog, fen, and swamp) over a 1-year period. General microbial activity (soil respirometry) and phenol oxidase enzyme activity were determined in the same peatlands to elucidate mechanisms underlying the differences in DOC and phenolics contents. The concentrations of DOC varied 25.5-45.4 (bog),29.2-71.4 (fen), and 13.5-87.6 (swamp) mg/L, while phenolic concentrations ranged 13.3-48.1 (bog), 7.6-29.5(fen) , and 4.9-30.8 (swamp) mg/L. The seasonal variations of DOC and phenolics in the swamp suggest that litterfall may be one of the most important factors for the DOC dynamics in such systems. The lowest microbial activity and phenol oxidase activity were found in the bog, which appears to Induce high percentage of phenolic contents in pore-water from bogs. It is also suggested that not only the DOC concentrations but also composition of DOC is of great importance in wetland biogeochernistry.

An Experimental Study on SOx and PM Reduction by Sulfur Content in Light Duty Diesel Engine (소형디젤기관에서 황함유량에 따른 SOx 및 PM저감에 관한 실험적 연구)

  • Han, Yeong-Chul;O, Yong-Seok
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.4
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    • pp.387-392
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    • 1998
  • Recently, among after-treatment devices which have high possibility of utility, diesel oxidation catalyst (DOC) is concerned over the world. DOC oxidizes pollutants by means of activate-reaction during by -passing in the catalyst, in doing so, conversion efficiency of PM, CO and HC is high, and this device does not have an effect on engine performance because back pressure is not nearly increased. But, as a small amount of sulfur content in fuel is oxidized, it makes sulfate, which is absorbed on the surface of catalyst. So, in this study, the experiment is carried out by means of using ordinary fuel (0.1wt%) and low sulfur fuel (0.05wt%) with DOC, and the emission gas of diesel engine is measured.

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Pilot Scale Assessment of DOC and THMs Removal in Conventional Water Treatment System

  • Lee, Choong-Dae;Lee, Yoon-Jin
    • Journal of Environmental Science International
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    • v.15 no.9
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    • pp.829-834
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    • 2006
  • This research aims to investigate the behavior of organic matter that causes bacterial re-growth and the formation of disinfectant by-products such as THM in water treatment, and to optimize conditions for a more efficient and conventional water facility. THM removed 51 % and 12 % through coagulation/sedimentation and filtration using a selected conventional system. In this experiment, the removal ratio of DOC was highest at 68 % when the Gt value was 42,000 and lowest at 41 % when the Gt value was 30,000. 77-84 % of total DOC was removed during coagulation/sedimentation, and 15-23 % was removed during filtration. When Gt values were between 30,000 and 66,000, over 50 % of high molecular matter above 10 K during coagulation/sedimentation was removed. Turbidity removed 98 % when the G1 value was 66,000. As the Gt value increased, the turbidity removal ratio increased. Turbidity removed over 20 % during the filtration process.

A Study on Emission Reduction by Diesel Oxidation Catalyst in Diesel Engine (CI기관에서 디젤산화촉매장치에 의한 배출가스 저감에 관한 연구)

  • 김경배;한영출;강호인
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.4
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    • pp.164-170
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    • 1996
  • Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

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