이종재 마찰용접재 강도특성과 초음파 반사계수와의 상관성에 관하여 실험적으로 연구한 결과의 요약은 다음과 같다. 1. 이종재 마찰용접 이음면에서의 초음파 반사계수를 펄스반사법에 의하여 측정산출할 수 있다. 2. 5MHz의 비교적 낮은 주파수의 탐촉자를 사용하므로써 시험편의 표면가공 오차를 무시할 수 있다. 3. 알루미늄과 스테인레스의 마찰용접에서는 용접조건으로 마찰가열시간이나 가열압력을 변수로 하였을 때보다 업셋가압력을 변수로 하였을 때 반사계수의 변화가 뚜렷하다. 4. 업셋가압력을 변수로 한 용접조건과 반사계수사이에는 선형적 상관관계가 있다. 5. 용접이음면에서의 이음인장강도와 반사계수와의 상관관계식을 정량적으로 도출할 수 있다. 6. 초음파 반사계수에 의해 이종재 마찰용접 품질의 비파괴적 평가가 가능하다

중금속류의 유관산업의 증대로 부수적으로 배출되는 중금속의 농경지오염도 증가되는 경향에 있는바, 공업단지주변의 답토양에 함유된 구리, 아연, 납, 카드뮴을 원자흡광분석법으로 정량하였다. 공시토양의 채취지역은 경인지방과 전북(전주 및 이리공단)으로 국한했는데 이 dusr에서 얻은 결과를 요약하면 다음과 같다. 1. 각종 중금속 공히 시흥군 서면지역(Cu : 23.09 ppm, Zn : 113.4 ppm, Pb : 86.3 ppm, Cd : 2.05 ppm)의 함량이 가장 높고, 안양천주변(Cu : 8.5 ppm, Zn : 16.6 ppm, Pb = 7.9 ppm, Cd : 0.33 ppm) , 김포부천(Cu : 7.4ppm, Zn : 8.2 ppm, Pb : 8.5 ppm, Cd : 0.14 ppm)의 순으로 그 함량이 낮았으며, 시흥군서면의 경우는 인근에 소재했든 아연광산의 영향으로 높은 수치를 나타낸 것으로 보며, 전주와 이리지역은 자연부존량의 최소치에 근사할 정도의 매우 낮은 함량이었다. 2. 안양천변과 인접한 경작지는 하류에 갈수록 중금속류의 함량이 높아지는 경향이 있으며, 특히 구로공단지역은 가장 높았다. 3. 경인김포지역은 부평수출공단지역이 가장 높은 함량이고, 한강을 농업용수원으로 이용하는 계양면이 가장 낮았으며, 고촌면의 상류의 부평공단경수가 오염되어 계양면보다 높은 경향을 나타낸 것으로 보아진다. 4. 각종 중금속류의 함량분포를 보면, Cu, Zn, Pb는 시흥군서면외는 대부분 10 ppm 미만이며, Cd는 0.2 ppm 미만이 대부분을 차지하고 있는데, 이같은 함량은 수도의 생육장해농도와 비교할 때 극히 낮은 안전한 함량이었는데, 비교적 높은 함량을 보인 시흥군서면지역은 앞으로의 축적상태를 단속하여 구명할 필요가 있다고 본다.으키지 않았다.) (5) 충영내 유충의 밀도는 약제의 종류, 농도에 따라 현저한 차이가 있었다. Omethoate, Salithion처리에서 충영내 유충밀도가 낮었다. 농도가 낮어짐에 따라 충영당 유충의 밀도가 높아지는 경향을 보였다. 충영내유충의 밀도는 7월 15, 7월 17일 처리에서만 조사 되었는데 처리시기간에는 차이를 인정할 수 없었다. 희석한계는 , 그리고 보존한계는 2 일이었다. 8. 마늘 모자이크 바이러스의 순화는 2회의 분획원심과 Sephadex gel filtration에 의해서 가능했다. 9. 전자현미경하에서 관찰한 마늘 모자이크 바이러스는 길이 1200-1225mu 폭 10-12mu의 사상이었다. 10. 혈청학적 미량침강 반응법에 의해 마늘잎에서뿐만 아니라 인편과 주아에서도 마늘 모자이크 바이러스의 검정이 가능했다. 11. 우리나라 5개 지방에서 수집한 마늘 종구 150개와 주아 30개에 대해 혈청학적방법으로 마늘 모자이크 바이러스의 감염률을 조사한 결과 의 감염률을 보였다. 12. 마늘 모자이크 바이러스와 크기가 근사한 Potato Virus X. Potato virus Y, Potato virus S, Potato virus M 등과의 혈청학적 유연관계를 조사한 바, 마늘 모자이크 바이러스는 이들과 구별되는 다른 바이러스라고 생각된다. 13. 마늘의 모자이크 감염주에서 단일계통으로 분리하여 본 실험에 사용한 바이러스는 마늘의 바이러스 무감염주를 얻을 수가 없기 때문에 직접 마늘잎에 접종해서 모자이크톤의 병원이라는 것을 확인할 수 없었지만, 검정식물상의 반응, 혈청학적반응, 전자현미경적 관찰등의 간접적인 조사 결과로 미루어 미인록의 마늘모자이크 바이러스라고 생각된다.TEX> 구에서는 의 난기 치사율을 나타내었고 F2

Environmental contamination by organic compounds are not only restricted to water, but extends to soil and groundwater as well. However, highly oxidized compounds, such as halogenated organics and nitro-compounds, can be detoxified employing reducing methods. Permeable reactive barrier is one of the representative technologies where zero-valent metals (ZVMs) are employed for groundwater remediation. However, organics contaminates often contaminate the unsaturated zone above the groundwater. Despite the availability of technologies like soil vapor extraction and bioremediation, removing organic compounds from this zone represents several challenges. In this study, the reduction of nitrobenzene to aniline was achieved using zero-valent iron (ZVI) under unsaturated conditions. Results indicated that the water content was an important variable in this reaction. Under dry conditions (water content = 0.2%), the reduction reaction was inhibited; however, when the water content was between 10% and 25% (saturated condition), ZVI can reduce nitrobenzene. Palladized iron (Pd/Fe) can be used to reduce nitrobenzene when the water content is between 2.5% and 10%. The reaction was evaluated over a wide range of temperatures (10 – 40 °C), and the results indicated that increasing the temperature resulted in increased reaction rates under unsaturated conditions.

In this study, the effects of single and binary heavy metals toxicity on the growth and phosphorus removal ability of Bacillus sp.. known as be a phosphorus-removing microorganism, were quantitatively evaluated. Cd, Cu, Zn, Pb, Ni were used as heavy metals. As a result of analysis of variance of the half of inhibition concentration and half of effective concentration for each single heavy metal treatment group, the inhibitory effect on the growth of Bacillus sp. was Ni < P b < Z n < Cu < C d. A nd the inhibitory effect on phosphorus removal by Bacillus s p. w as N i < Pb < Z n < Cu < C d. When analyzing the correlation between growth inhibition and phosphorus removal efficiency of a single heavy metal treatment group, a negative correlation was found (R2 = 0.815), and a positive correlation was found when the correlation between IC50 and EC50 was analyzed (R2 = 0.959). In all binary heavy metal treatment groups, the interaction was an antagonistic effect when evaluated using the additive toxicity index method. This paper is considered to be basic data on the toxic effects of heavy metals when phosphorus is removed using phosphorus removal microorganisms in wastewater.

In this research, heavy metals and T-P removal characteristics of plated wastewater are derived using BPC(Break Point Chlorination) process. AA sedimentation pond outflow(Influence) was evaluated for the removal efficiency of heavy metal(Ni) and T-P at a reaction time of 25 minutes by NaOCl input volume(9, 11, 13 and 15 mL). In the case, the higher the NaOCl input volumes, the higher the ORP values were maintained and the higher the removal efficiency tended to be. On the other hand, T-P was judged to have a low relationship between the ORP value and the removal efficiency. In addition, the efficiency of removal heavy metals and T-P in the plated wastewater by injecting 10 mL, 15 mL, 20 mL and 25 mL NaOCl, increased as the amount of NaOCl injected increased, the amount of NaOH input for pH increased. It was found that suspended solid in effluence also increased. It was also observed that the color of the plating wastewater changed from yellowish green to green to charcoal gray to black as the amount of NaOCl injected increased. Treatment characteristics of the reaction time, the longer the reaction time with the substance to be treated after the input of NaOCl, the more the heavy metal removal efficiency tended to increase. Through XRF analysis of the sludge, the constituents in the sludge such as NaCNO, CNCl, Na3PO4, CrO4, 2Na2CrO4 and 2NaNO3 will be analyzed in detail, and the mechanisms of the reaction between the plated wastewater and the complex compound will be elucidated.

본 연구는 중금속 오염지역의 토양정화에 적합한 식물을 선발하기 위해 국화과 15종을 중금속으로 오염된 토양에 8주 동안 재배한 다음 생육반응과 부위별 비소, 카드뮴, 구리, 납, 아연 등의 중금속의 축적능을 분석하였다. 톱풀을 제외한 가새쑥부쟁이, 금계국, 감국, 각시취 등의 생육은 비교적 양호하였다. 비소 축적능은 더위지기 지하부(25.52 ㎎·㎏-1)에서 가장 높았고 지상부는 바위구절초(3.35 ㎎·㎏-1)가 가장 우수하였다. 카드뮴은 왕갯쑥부쟁이 지상부(2.50 ㎎·㎏-1)에서 가장 높았다. 구리 축적능은 지상부와 지하부 모두 각시취(24.29, 99.92 ㎎·㎏-1)가 가장 높은 경향을 보였다. 국화과 15종의 지상부는 1.43(왕갯쑥부쟁이)∼5.00 ㎎·㎏-1(수리취)의 납이 축적되었다. 눈갯쑥부쟁이(140.09 ㎎·㎏-1), 쑥부쟁이(109.07 ㎎·㎏-1), 왕갯쑥부쟁이(100.21 ㎎·㎏-1) 등의 아연 축적능은 100 ㎎·㎏-1 이상으로 아연 오염 지역의 식물상 정화 기법 소재로 활용이 가능할 것으로 생각된다.

Bioremediation has been recognized as a suitable alternative to conventional methods of removing contaminants, and it uses fungi, bacteria and microalgae. In contrast to other organisms, microalgae are unique in that they have the ability to perform photosynthesis like plants and to utilize organic/inorganic carbon substrates, in a process called phytoremediation. Microalgae can populate a reaction site rapidly and enhance the bioremediation efficiency. In this study, Chlorella vulgaris was used to evaluate the removal potentials of the nutrients (N and P) and heavy metals (Cu and Zn) from swine wastewater. The optimum growth conditions for Chlorella vulgaris and the removal potentials of N, P, Cu, and Zn from synthetic wastewater using Chlorella vulgaris were investigated. Based on the results, the applicability of this microalga to on-site wastewater treatment was examined. Optimal growth conditions for Chlorella vulgaris were established to be 28℃, a pH of 7, and light and dark cycles of 14:10 h. As the concentrations of the nutrients were increased, the efficiencies of N and P removal efficiencies by Chlorella vulgaris were decreased in the single and binary mixed treatments of the nutrients, respectively. Further, the efficiencies of Cu and Zn removal also decreased as the heavy metals concentrations added were increased, both in the single and binary mixed treatments. In addition, the efficiency of Cu removal was higher than that of Zn removal. Our results indicate that Chlorella vulgaris could be used in treatment plants for the removal of nutrients and heavy metals from swine wastewater.

Trains have been a major means of transport in Korea during these past decades. However, train facilities such as stations and repair shops are contaminated with organic and inorganic substances. There is a high probability of train facility contamination with polyaromatic hydrocarbons (PAHs). This study evaluated the PAH and heavy metal contamination of soil near railroads in the Kyungpook area. A total of 18 soil samples were collected from the railroads and analyzed for 16 PAHs and 6 heavy metal species. The contamination level of the top soil was found to be slightly higher than that of the subsoil for contamination with PAHs. The ratio of carcinogenic PAH concentration to the total PAH concentration was relatively high, with a maximum of 0.9. The toxicity equivalent (TEQ) of the PAHs were 500.6 ng/kg in the topsoil and 355.5 ng/kg in the subsoil. The ratio of low molecular PAHs (LPAHs) to high molecular PAHs (LPAHs) ranged from 6.7 to 29.5; this shows that contamination is primarily due to combustion of fuel rather than due to petroleum. The ratio of phenanthrene to anthracene and the ratio of fluoranthene to pyrene also show that contamination occurred due to combustion for transportation. The heavy metal contamination level was lower than the Korean standard, but higher than the background concentration; this indicates that the soil was affected by the operation of the railways.

The purpose of this study was to verify safe and environmentally-sound recycling of blast-furnace slag in the cement industry. This was accomplished by analyzing the heavy metal contents of three kinds of raw materials: blast-furnace slag, Portland cement, and the substitutes, which were mainly input into the manufacture of cement. The research revealed that, in the five samples tested, the heavy metal level in the blast-furnace slag cements (5.90 ~ 8.38 mg/kg for Cr6+) is lower than the ordinary Portland cement (11.04 ~ 14.92 mg/kg for Cr6+). This suggests that both raw materials have low heavy metal contents compared with the 20 mg/kg limit enforced by the autonomic convention in Korea. As for the substitutes, there was no decisive effect on the overall heavy metal content because of the low input ratio of 2.5%. Therefore, it is of high utility value to recycle the blast-furnace slag in the cement industry, considering slag can dilute the overall heavy metal contents in the cement products.

A continuous process of persulfate oxidation and citric acid washing was investigated for ex-situ remediation of complex contaminated soil containing total recoverable petroleum hydrocarbons (TRPHs) and heavy metals (Cu, Pb, and Zn). The batch experiment results showed that TRPHs could be degraded by Fe2+ activated persulfate oxidation and that heavy metals could be removed by washing with citric acid. For efficient remediation of the complex contaminated soil, two-stage and three-stage processes were evaluated. Removal efficiency of the two-stage process (persulfate oxidation - citric acid washing) was 83% for TRPHs and 49%, 53%, 24% for Cu, Zn, and Pb, respectively. To improve the removal efficiency, a three-stage process was also tested; case A) water washing - persulfate oxidation - citirc acid washing and case B) persulfate oxidation - citric acid washing (1) - citric acid washing (2). In case A, 63% of TRPHs, 73% of Cu, 60% of Zn, and 55% of Pb were removed, while the removal efficiencies of TRPHs, Cu, Pb, and Zn were 24%, 68%, 62%, and 59% in case B, respectively. The results indicated that case A was better than case B. The three-stage process was more effective than the two-stage process for the remediation of complex-contaminated soil in therms of overall removal efficiency.

Hazardous metals leaching experiment was carried out in accordance with various usage environments for camping cooking utensils distributed in the market. There was a significant difference in the degree of migration for lead, arsenic, cadmium and nickel defending on the solvent and how to use, although they were all appropriate for criteria. In general, the migrated amount of aluminum was increased in acidic condition, and the migrated amount of arsenic was increased in salty condition. Physical scratches increased the overall release of hazardous metals from the portable pots and pans for camping in all solvents. Especially, in 0.5% citric acid solution, cadmium was migrated by physical scratch in stainless steel and hard aluminum pots and pans. The longer the leaching time, the higher the migration of aluminum in acid condition and arsenic in basic condition. From these results, it is desirable to use the cooking utensil for camping without being exposed to strong acidic or basic solution and scratches in order to reduce the migration of hazardous metals from them.

The purpose of this study is to understand the current situation for waste generation from domestic industries and to calculate the designated waste generation containing heavy metals using Korean waste statistics. Analytical data regarding heavy metals for hazardous waste in a previous study was reviewed. In addition, the designated waste generation for each heavy metal was estimated by comparing the data of the Allbaro system (2014). The designated waste generations were, in order, Pb > CN−> Cd > Cu > Hg > Cr6+ > As, and the sludge, ash, slag, dust, etc. generated from the process of wastewater treatment, plating and anodizing of metals, waste treatment, and the manufacture of basic iron and steel, considered as designated waste containing heavy metals, were investigated. The waste generation with heavy metals was 1.812 % of the total waste generation, which is higher than the 1.317 % collected from the Allbaro system (2014). These results will be used as a baseline in establishing waste management policy. Further analytical data about heavy metals in the designated wastes that are mentioned in this study are required for a more accurate picture of waste generation containing heavy metals.

도금산업은 국가 핵심역량 사업분야인 전기재료 및 전자 부품 산업등과 밀접한 관계를 가지고 있는 산업분야일 뿐만 아니라, 핵심 부품 및 소재의 기능적 특성과 부가가치를 향상시켜 가격을 결정하는 품질에 큰 영향을 미치는 기반 산업이지만 배출 폐수에는 중금속 이외에도 맹독성 물질인 시안화물과 주요 오염물질이 대량 포함되어 있어 주요 유해물질 배출 관리 대상 업종으로 분류되어 집중 관리되고 있는 실정이다. 이에 소규모 국내 도급업체는 공동 폐수처리장을 통해 폐수를 처리하고 있으나, 도금방법이나 폐수의 특성에 따라 분리 배출되어지지 않고 대부분 통합 배출되어짐으로 인해 처리공정이 복잡하고 처리시설이 방대해지며 많은 처리비용이 소요되고 있어 도급산업을 위축시키는 원인으로 지목되고 있다. 최근 이러한 문제의 해결을 통해 도금산업을 강화하고자 이온성 물질을 분리해 정제할 수 있는 전기투석 기술을 이용한 다양한 연구가 진행되고 있다. 본 연구에서는 전기투석 장치를 이용하여 도금폐수내 구리와 니켈의 제거성능을 평가하였다. 전기투석장치의 이온교환막은 Astom사의 NEOSEPTA를 이용하였고 총 5쌍의 음이온 교환막과 양이온 교환막으로 구성된 스택을 제작하였다. NaCl을 이용하여 TDS 4,000mg/L, 니켈과 구리의 농도를 각각 20mg/L로 제조한 합성폐수를 이용하여 실험한 결과, 한계전류 12v와 25분의 체류시간 조건에서 구리와 니켈은 모두 99%이상 제거되었다. 또한 동일조건에서 유량이 증가할수록 구리와 니켈의 제거효율도 증가하는 경향을 나타내었다. 이온교환막의 변경에 따른 처리성능을 평가한 결과, 이온교환막의 종류에 따라 처리성능에 차이를 나타내어 추가적인 연구가 필요한 것으로 판단된다.

중금속으로 오염된 토양과 광미는 지하수 및 생태계에 추가적으로 피해를 발생시킨다. 이러한 독성 금속의 축적은 식물의 성장억제 및 인체의 발달이상, 발암과 같은 다양한 질병의 원인이 된다. 오염된 토양에서 중금속을 정화하는 방법으로는 고형화/안정화, 토양세척, 토양경작법 등과 같이 다양한 방법이 있다. 하지만 부지 및 오염특성에 따라 적절한 방법을 사용해야 한다. 적절한 방법 중 하나는 오염된 토양의 고형화/안정화이다. 본 연구의 목적은 오염된 토양 및 광미 내 존재하고 있는 중금속을 고형화/안정화 공법을 적용하여 정화하는 방법을 제안하는데 있다. 본 연구에서는 오염토양 내 중금속을 고형화/안정화 시키고 강도 증진을 위해 MICP 토착미생물과 산업폐기물인 굴패각, 폐석고를 배합하여 고화제로 사용하였다. 국내의 중금속 오염토양과 광미에서 MICP 토착미생물을 분리하였고 균체 지방산 분석을 통하여 동정을 진행하였다. 각각의 시료에서 분리한 균주를 동정한 결과 가장 많이 유사성을 보이는 균주는 Brevibacillus centrosporus 와 Bacillus megaterium 이었다. 또한 MICP 토착미생물의 최적 성장 조건을 도출하였으며, 산업폐기물과 MICP 토착미생물의 최적 배합비를 적용한 공시체의 일축압축강도 분석을 진행하였다. 그 결과 28일 경과 후 일축압축강도는 미국 EPA 폐기물처리 표준 기준을 만족하였으며, 위해성 평가를 위한 TCLP, SPLP 분석 결과 미국 EPA 기준을 만족하였다.

For 26 soil series distributed more than 1% among 63 soil series in Jeju Island, natural uncultivated soil samples were collected. For these soils, the chemical speciation of eight heavy metals (Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) was examined. Further, the Plant Bioavailability (PB) and Mobility Factor (MF) of these heavy metals were evaluated using Tessier’s 5-step sequential extraction method (exchangeable, carbonate, reducible (bound to Fe/Mn oxides), oxidizable (bound to organic matter), and residual fraction). The main form present was residual fraction for Cd and Zn; residual and oxidizable fractions for Cr, Cu, Ni, and Pb; reducible fraction for Mn; and carbonate fraction for V. The average plant availability and average mobility factor were found to be V (57.37%) > Zn (12.49%) > Cd (11.76%) > Cu (11.19%) > Pb (9.37%) > Cr (9.09%) > Mn (3.13%) > Ni (2.63%), and Mn (61.04%) > V (59.94%) > Zn (31.54%) > Cd (17.65%) > Cr (15.66%) > Ni (13.89%) > Pb (13.80%) > Cu (13.53%), respectively.

This study was performed to develop the efficient phytoremediation model in the paddy soil contaminated with heavy metals by cultivating Pteris multifida and Artemisia princeps with different mixing ratios (1:0, 8:1, 6:1, 4:1). As a result of investigating the heavy metal accumulation of each plant per dried material (1 ㎏), content of arsenic and cadmium was the highest in aerial part of P. multifida (169.82, 1.70 ㎎·㎏-1 DW, each) among the treated group. Lead content was the highest (12.58 ㎎·㎏-1 DW) in the aerial part of P. multifida cultivated with 8:1 mixed planting. But the content of copper and zinc was the highest (33.94, 61.78 ㎎·㎏-1 DW, each) in the aerial part of A. princeps with 8:1 treatment. Regardless of heavy metals, plant uptake from the 1 ㎡ soil was the highest in 4:1 mixed planting group, which showed the best yield of A. princeps.

Aeration with low energy micro-bubble generation and UV/H2O2 processes was introduced to verify the possibility of oxidation treatment for acid mine drainage. During 10 hours of aeration with micro-bubbles, Fe and As concentrations were decreased to 18.1 and 61.8%, respectively, while Cu, Cd, Al were kept at influent concentrations. Other heavy metals such as Mn, Cr, Pb, Zn, and Ni concentrations fluctuated due to the repetition of oxidation and release. Twenty days of aeration indicated the oxidation possibility for Cu, Cd, and Al. With the employment of UV/H2O2 processes, more than 77% of Cu and Fe removed, whereas slightly more than 30% of Cd and Al removed.

Raw and secondary waste materials from recycling products have been used to produce cements. A total of 10 cements produced from recycling products were analyzed for chemical composition, such as Na2O, MgO, Al2O3, SiO2, SO3, Cl, K2O, CaO, TiO2, Cr2O3, MnO, Fe2O3, CuO, ZnO, and PbO, using the Korean standard leaching test. The total content of toxic substances, such as Pb, Cd, Cu, As, Hg, and Cr(VI), present in each cement was also measured. The corrosion characteristics of cement leachates were also determined by measuring their pH values using an ion selective electrode and measuring the corrosion rate of a circular steel plate in each leachate. The chemical composition of the cements was found to be 60-67% CaO, 18-23% SiO2, and 5-6% Al2O3. Based on the results of the leaching tests, the samples did not exceed the prescribed regulatory leaching levels. The total content of toxic substances in each cement did not exceed the voluntary agreement criteria of 20 mg/kg. In the case of the corrosion characteristics of the cement leachates, the pH of each leachate was greater than 12.5 and the corrosion rate of a circular steel plate in each leachate did not exceed 6.35 mm/yr. The correlation between pH and the corrosion rate of steel in the solid waste leachates was difficult to determine.