• 유기물자원화
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• 제30권4호
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• pp.67-83
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• 2022

바이오차는 바이오매스를 산소가 제한된 환경에서 고온(300~700℃)으로 열분해하여 얻어지는 탄소 함량이 높은 생성물이다. 최근 바이오차는 농업 부산물을 최소화하고 순환 경제의 효율성을 높이는 효과적인 도구로 농업 및 환경 분야에서 다양한 용도로 널리 사용되고 있다. 바이오차를 만드는 재료로 왕겨, 가축분, 보릿짚 등 여러종류의 유기성 부산물이 사용되고 있으며, 약 10% 바이오차 적용(wt/wt)은 작물의 수확량, 토양 탄소 격리량을 높여준다는 연구 결과가 있다. 우리나라 농경지의 경우 논에서 밭으로 토지 이용이 전환되거나 간척으로 인한 갯벌이 논으로 개간되고, 산림에서 밭이나 시설재배지로 개간되는 경우가 발생한다. 그러므로 농경지 전환으로 인한 농경지별 바이오차 적용 효과가 상이할 것으로 판단된다. 그러나 국내에서 농경지 유형별 바이오차 종류와 투입 수준에 따른 토양 탄소저장 연구는 여전히 미흡한 상황이다. 이에 본 연구는 농경지 토양별 바이오차 종류와 투입 수준에 따른 토양 탄소저장과 무기화되어 배출되는 이산화탄소(CO₂) 배출량을 정량적으로 평가하였다. 본 연구에 사용한 재료는 보릿짚, 가축분을 수거, 건조 등 전처리 과정을 거친 후 충남 예산에 있는 바이오차 제조공장 탄화로를 이용하여 TLUD (Top Lit Up Draft) 상향 통풍형 열분해 방식으로 약 500℃에서 제조하였다. Kinetic 모델 적용 결과 토양에 투입된 탄소 무기화는 바이오차를 투입하지 않으면 토양 종류별 8.2~16.5% 비율로 탄소원이 무기화 되어 이산화탄소로 배출되었다. 노지 밭 토양에서 15.5~16.5%로 가장 높았고, 간척지 토양에서 8.2~8.7%로 가장 낮았다. 이는 토양 내 탄소 함량이 높은 토양에서 유기물의 분해가 상대적으로 높아 배출되는 이산화탄소(CO₂)는 탄소 함량에 비례하여 증가하는 것으로 판단된다. 바이오차를 투입한 토양에서 탄소 함량이 증가함에도 상대적으로 무기화되는 비율은 낮아졌다. 국제 바이오차협 회에서는 H:C 비율이 0.7 이하면 100년 이상 토양 내 탄소 격리효과가 있는 것으로 인정되고 있다. 본 연구를 통해 바이오차의 원료물질이 상이한 보릿짚, 가축분 바이오차 간 탄소 무기화에 미치는 영향이 상이할 것으로 판단했지만, 각각의 바이오차 H:C 비율이 0.30~0.39로 0.7 이하임으로 토양에 혼합하였을 때 탄소 무기화의 비율이 낮고 탄소 격리의 효과가 나타났다.

• 자원환경지질
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• 제17권4호
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• pp.289-298
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• 1984

Uraniferous black slates of the Okchon sequence occur in Koesan (northeast) through Miwon-Boun (middle) to the southwest off Taejon (southwest) within the Okchon fold belt. The Uraniferous balck slates in the southwest off Taejon are particularly well developed in Chubu (northeast) and Moksso-ri (middle) areas whereas they are less developed in Jinsan (southwest) area. The uraniferous beds range from less than a meter to 40 meters in thickness and range from less than 0.02% $U_3O_8$ (cut-off-grade) to 0.05% $U_3O_8$ in the southwestern district off Taejon. Electron microprobe analysis of uranium-minerals found in graphitic slate samples enables to estimate their major compositions semi-quantitatively so that uraninite, ferro-uranophane and chlopinite are tentatively identified. Uranium-minerals are closely associated with carbon and metal sulfides. Correlation analysis of trace element concentrations revealed that U and F.C., and U and Mo are lineary correlative respectively and their correlation coefficients are positively high whereas those of U and V, U and Mn, and U and Zr are negatively low, implying that uranium mineralization has been closely related with concentrations of carbon and molybdenum. Stable isotope analyses of pyrite sulfur range widely from +11.5% to -23.3% in ${\delta}^{34}S$ values whereas those of graphite carbon fall within a narrow range between -23.3% and -28.9% in ${\delta}^{13}C$ values. The wide range of ${\delta}^{34}S$ values suggests that the sulfur could be of meteoric origin rather than of igneous source. The narrow range of ${\delta}^{13}C$ values, which are close to those of coal, indicates that the graphite is organic carbon in origin. Therefore, it is concluded that the uranium mineralization in the Okchon sequence took place primarily in sedimentary environment rich in organic matter and sulfide ion, both of which served as the reducing agents to convert soluble uranyl complex to insoluble uranium dioxide.

• 에너지공학
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• 제26권1호
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• pp.76-83
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• 2017

In this paper, the carbon resources recycling of the overview of coffee waste generation in Vietnam. Since few years, there has been a significant research studies was done in the areas of coffee waste generation areas and also waste water generation from coffee production. The coffee residue (solid) and waste water (liquid) both are caused the underground water contamination and also soil contamination. These residues contain high organic matter and acid content leads to the severe threat to environment. In second stage of coffee production process, the major solid residue was generated. Various solid residues such as spent coffee grounds, defective coffee beans and coffee husks) pose several environmental concerns and specific problems associated with each type of residue. Due to the unlimited usage of coffee, the waste generation is high. At the same time, some researchers have been investigated the spent coffee wastes are the valuable sources for various valuable compounds. Biodiesel or biomass productions from coffee waste residues are the best available utilization method for preventing the landfill problems of coffee waste residues.

• 대한환경공학회지
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• 제35권12호
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• pp.861-866
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• 2013

본 연구의 목적은 가축사체 매몰지 토양에서 추출된 미생물을 이용하여, 가축사체 매몰지 오염 토양 유래 유기탄소의 분해 효과를 분석하고, 분해에 관여하는 미생물의 종을 규명하는 것이다. 경기도 안성에 위치한 가축 매몰지 토양 유래 용존 유기탄소를 대상으로 토양 서식 미생물의 생분해율을 평가한 결과(56일 동안), 1번 용액(초기 용존 유기탄소 농도 = 19.88 mg C/L)에서는 13일 이내에 48%의 용존 유기탄소가 감소하였으며, 56일째 용존 유기탄소는 $8.8{\pm}0.4$ mg C/L로 56% 분해되었다. 2번 용액(초기 용존 유기탄소 농도 = 19.80 mg C/L)에서도 초기 13일 이내에 용존 유기탄소 농도가 급격히 감소하였으며, 56일째 용존 유기탄소는 $6.0{\pm}1.6$ mg C/L로 70%가 분해되었다. 생분해 실험과정에서, 전체 유기탄소 물질에서 방향족 탄소구조의 비율을 나타낸 지표인 $SUVA_{254}$값은 용존 유기탄소와는 다르게, 일정기간(21일) 동안 증가하다가 감소하는 경향을 나타냈다. $SUVA_{254}$값은 1번 용액과 2번 용액 모두, 21일째 가장 높은 값을 나타내었다. 생분해 실험 14일째 미생물 분석 결과, 토양에서 쉽게 발견되는 Pseudomonas fluorescens, Achromobacter xylosoxidans, Nocardioides simplex, Pseudomonas mandelii, Bosea sp. 등 미생물이 검출되었다. 그리고, 56일째 미생물 분석 결과, Pseudomonas veronii가 우점종으로 나타났다.

• 에너지공학
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• 제27권2호
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• pp.70-80
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• 2018

Natural organic matter (NOM) is among the most common pollutant in underground and surface waters. It comprises of humic substances which contains anionic macromolecules such as aliphatic and aromatic compounds of a wide range of molecular weights along with carboxylic, phenolic functional groups. Although the concentration of NOM in potable water usually lies in the range of 1-10 ppm. Conventional treatment technologies are facing challenge in removing NOM effectively. The main issues are concentrated to low efficiency, membrane fouling, and harmful by-product formation. Ion-exchangers can be considered as an efficient and economic pretreatment technology for the removal of NOM. It not only consumes less time for pretreatment but also resist formation of trihalomethanes (THMs), an unwanted harmful by-product. This article provides a comprehensive review of ion exchange processes for the removal of NOM.

• 한국토양비료학회지
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• 제49권5호
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• pp.510-516
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• 2016

Soil respiration has been recognized as a key factor of the change of organic matter and fertility due to the carbon and nitrogen mineralization. In this study, we evaluated the effect of soil respiration on the light fraction-C and inorganic N content depending on temperature in soil applied with organic matter. Soil respiration was calculated by using total $CO_2$ flux released from soil applied with $2Mg\;ha^{-1}$ of rice straw compost and rye for 8 weeks incubation at 15, 25, $35^{\circ}C$ under incubation test. After incubation test, light fraction and inorganic N content were investigated. Rye application dramatically increased soil respiration with increasing temperature. $Q_{10}$ value of rye application was 1.69, which was higher 27% than that of rice straw compost application. Light-C and $NO_3-N$ contents were negatively correlated to soil respiration. Light-C in rye application more decreased than that in rice straw compost with temperature levels. These results indicate that temperature sensitivity of soil respiration could affect soil organic mater content and N availability in soil due to carbon availability. Also, light fraction would be useful indicator to evaluate decomposition rate of organic matter in soil under a short-term test.

• 자원환경지질
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• 제19권spc호
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• pp.163-173
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• 1986

Black and graphite slates from the Okcheon metamorphic belt contain enriched values of uranium (average 200~250ppm) and molybdenum (average 150~200ppm). Uranium mineralization is closely associated with quartz and sulfide veinlets which are formed diagenetically in graphite slate. The uranium minerals were concentrated in outer part of graphite nodules. The ${\delta}^{13}C$ values of organic carbon from the metasediments including uranium bearing graphite slate range from -15.2 to -26.1‰ with a mean of -23.5‰. Meanwhile, ${\delta}^{13}C$ values of coal and coaly shale from some Paleozoic coal fields of South Korea vary from -19.4 to -23.9‰ with an average of -22.5‰. Isotopic compositions of vein calcite in uranium bearing slate range from -13.4 to -15.4‰ in ${\delta}^{13}C$ and +11.3 to +15.1‰ in ${\delta}^{18}O$ could indicate a reduced organic carbon source isotopically exchanged with a graphite of biogenic origin. Metamorphic temperature determined by a calcite-graphite isotope geothermometer was 383~$433^{\circ}C$ which corresponded to greenschist facies by Miyashiro (1973) and is consistent with metamorphic facies estimated by mineral assemblages (Lee, et al., 1981, and Kim, 1971). The fixation of uranyl species by carbonaceous matter in marine epicontinental environment, and remobilization of organouranium by diagenetic processes have attributed to the enrichment of uranium and heavy metals in the graphite slate of Okcheon metamorphic belt.

• Environmental Engineering Research
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• 제23권2호
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• pp.129-135
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• 2018

The aim of this study is to assess the applicability of ferrate(VI) in the efficient treatment of aqueous waste contaminated with potassium hydrogen phthalate (KHP) which is known to be a potent endocrine disrupting chemicals. Simulated batch reactor operations were conducted at a wide range of pH (7.0 to 12.0) and molar ratios of KHP to ferrate(VI). Kinetic studies were performed in the degradation process and overall rate constant was found to be 83.40 L/mol/min at pH 8.0. The stoichiometry of ferrate(VI) and KHP was found to be 1:1. Further, lower pH values and higher KHP concentrations were favoured greatly the degradation of KHP by ferrate(VI). Total organic carbon analysis showed that partial mineralization of KHP was achieved. The presence of several background electrolytes were studied in the degradation of KHP by ferrate(VI).

• Environmental Engineering Research
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• 제24권3호
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• pp.513-520
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• 2019

In this investigation, nano ZnO was sonochemically synthesized by a novel method using a methionine precursor. A narrow size distribution (41-50 nm) of nano ZnO was achieved that was immobilized on perlite and applied as a catalyst in catalytic ozonation. The catalyst was characterized by fourier transform infrared spectroscopy, BET surface area, and field emission scanning electron microscope. The ozonation of recalcitrant Remazol black 5 (RB5) di-azo dye solution by means of the synthesized catalyst was investigated in a bubble column slurry reactor. The influence of pH values (7, 9, 11), catalyst dosage (8, 12, 15, $20g\;L^{-1}$) and reaction time (10, 20, 30, 60 min) was investigated. Although the dye color was completely removed by single ozonation at a higher reaction time, the applied nanocatalyst improved the dye declorination kinetics. Also, the degradation of the hazardous aromatic fraction of the dye was enhanced five-times by catalytic ozonation at a low reaction time (10 min) and a neutral pH. The second-order kinetics was best fitted in terms of both RB5 color and its aromatic fraction removal. The total organic carbon analysis indicated a significant improvement in the mineralization of RB5 by catalytic ozonation using the nano-ZnO/perlite catalyst.

• 한국환경농학회지
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• 제30권1호
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• pp.9-15
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• 2011

본 실험은 비료 공급원으로서 1) 대조구(NF), 2) 상업용 유기질 비료($10N-2P_2O_5-8K_2O$, Nature Safe$^{(R)}$)(CF), 3) 계분 비료(PL)를 포함하였고, 멀칭 공급원으로는 4) 나무껍질 멀칭(WC), 5) 재활용 종이 멀칭(SP), 6) 식물성 퇴비 멀칭(GC), 7) 초생멀칭(GR)을 포함하였다. 유기질 비료와 멀칭의 양은 매해 유기농 사과나무 포장에 시비하였던 (50 g 질소/한 나무, 10 cm 멀칭시용/한 나무) 질소량과 체적에 각각 비례해서 각 포트에 시비하였다. CF, PL, 그리고 GR 급원은 미생물이 유기태 질소를 무기화(N-mineralization) 하는데 이상적인 탄소:질소(30:1이하)비를 보였는데, 처리 후 90일 째 되던 날에 토양중 무기태 질소 농도를 증가시켰다. CF, PL, 그리고 GR 처리된 유묘는 가장 넓은 총 엽면적과 두꺼운 직경, 그리고 큰 수고 및 건물중을 나타내어서 식물생장을 증가시키기 위한 가장 유용한 자재로 평가되었다.