This study aimed to develop an efficient recycling process for wastewater generated from soil-washing used to remediate uranium (U(VI))-contaminated soil. Under acidic conditions, U(VI) ions leached from the soil were precipitated and separated through neutralization using hydrazine (N2H4). N2H4, employed as a pH adjuster, was decomposed into nitrogen gas (N2), water (H2O), and hydrogen ions (H+) by hydrogen peroxide (H2O2). The residual N2H4 was precipitated when the pH was adjusted using sulfuric acid (H2SO4) to recycle the wastewater in the soil-washing process. This purified wastewater was reused in the soil-washing process for a total of ten cycles. The results confirmed that the soil-washing performance for U(VI)-contaminated soil was maintained when using recycled wastewater. All in all, this study proposes an efficient recycling process for wastewater generated during the remediation of U(VI)-contaminated soil.

최근 전기차 및 전력저장 시스템과 같은 대형 전지 시장의 성장으로 인해 리튬 이온 배터리에 대한 수요가 급증하 고 있다. 이에 따라 폐전지의 발생이 빠르게 증가할 것 으로 예상되며, 이에 대한 처리가 사회적 문제가 될 것 으로 예상된다. 폐전지 처리의 가장 효과적인 방법은 폐전지의 소재를 재활용하는 방법이다. 이 중 고가의 금속 물질로서, 재활용 시 경제성이 가장 높은 양극 소재 재활용 연구가 가장 활발히 이뤄지고 있다. 하지만 폐전지로부터 회수된 블 랙 파우더에는 도전재 및 바인더가 포함되어 있는데 양극 소재를 재활용하기 위해서는 이를 제거하는 공정이 필요하 다. 본 연구에서는 폐전지에서 추출된 폐양극 소재의 재활용을 위한 소재 전처리 연구를 제시한다. 열처리 및 화학 처리의 두 가지 전처리 공정을 사용하여 불순물을 제거하였고, 이에 따른 제거 정도를 SEM 분석을 통해 확인하였고, 불순물의 정량 분석을 TGA, EA 분석을 통해 확인하였으며, 전기화학 성능을 분석하였다.

Tungsten carbide is widely used in carbide tools. However, its production process generates a significant number of end-of-life products and by-products. Therefore, it is necessary to develop efficient recycling methods and investigate the remanufacturing of tungsten carbide using recycled materials. Herein, we have recovered 99.9% of the tungsten in cemented carbide hard scrap as tungsten oxide via an alkali leaching process. Subsequently, using the recovered tungsten oxide as a starting material, tungsten carbide has been produced by employing a self-propagating high-temperature synthesis (SHS) method. SHS is advantageous as it reduces the reaction time and is energy-efficient. Tungsten carbide with a carbon content of 6.18 wt % and a particle size of 116 nm has been successfully synthesized by optimizing the SHS process parameters, pulverization, and mixing. In this study, a series of processes for the highefficiency recycling and quality improvement of tungsten-based materials have been developed.

In this research, we evaluate on the disassemblability of recycling process for vehicle front door using the symbolic chart method and machine-learning algorithm. It is applied to the front door of 1600cc class vehicle, and then the conventional steel door and CFRP door were compared. Based on the principle symbolic chart method, the number of processes can be different according to decomposer proficiency of suitability of recycling process, so the evaluation method is required to supply this issue. The machine learning algorithm, and artificial intelligence method were applied and the applicable tools for each experiment were used to compensate the variations in the number of processes according to different proficiencies. Because CFRP front door has integrated components compare to steel door, so its disassemblability processes were decreased to 80 from 103 of the conventional steel door’s. It can be confirmed that the disassemblability was increased from the suitability of recycling equation. In case of the steel, disassemblability was approximately 60.6, in case of the CFRP is approximately 72 for car front door. Therefore, it can be concluded that the disassemblability of CFRP was better in the evaluation of suitability of recycling.

This study is carried out to obtain basic data regarding oxidation and reduction reactions, originated on the recycling of waste tungsten hard scraps by oxidation and reduction processes. First, it is estimated that the theoretical Gibbs free energy for the formation reaction of WO2 and WO3 are calculated as ΔG1,000K= -407.335 kJ/mol and ΔG1,000K = -585.679 kJ/mol, from the thermodynamics data reported by Ihsan Barin. In the experiments, the oxidation of pure tungsten rod by oxygen is carried out over a temperature range of 700-1,000oC for 1 h, and it is possible to conclude that the oxidation reaction can be represented by a relatively linear relationship. Second, the reduction of WO2 and WO3 powder by hydrogen is also calculated from the same thermodynamics data, and it can be found that it was difficult for the reduction reaction to occur at 1,027oC, in the case of WO2, but it can happen for temperatures higher than 1127oC. On the other hand, WO3 reduction reaction occurs at the relatively low temperature of 827oC. Based on these results, the reduction experiments are carried out at a temperature range of 500-1,000oC for 15 min to 4 h, in the case of WO3 powder, and it is possible to conclude that the reduction at 900oC for 2h is needed for a perfect reduction reaction.

온실가스로 인한 지구 온난화 현상이 기후 변화를 초래하고 있기 때문에 메탄과 이산화탄소 감축에 대한 저감 기술이 절실하다. 바이오가스는 음식물쓰레기 처리장, 축산분뇨처리장, 등에서 발생하는데, 본 연구는 음식물쓰레기처리장에서 바이오가스를 분리정제 하기 위해 제습, 탈황, 탈실록산 처리된 바이오가스를 막분리 공정으로 운전하였고, 유량, 압력, 막 면적에 변화에 따른 공정개선으로 98% 이상의 고순도 메탄가스와 90% 이상의 회수율을 만족하는 결과를 얻었다.

Most world-leading companies are aware that Environment and Health and Safety Issues are critical to the product quality and sustainable growth of their company. Environment-friendly efforts are seen in almost all aspects of business operations in an adva

The horizontal high energy rotor ball mill () is used to break and activate dry solids. It is used for dry-milling and in the vertical mount for wet-milling in leaching processes. Technical electric arc furnace (EAF) dust with high contents of zinc oxide, zinc ferrite and magnetite is efficiently separated by ambient temperature leaching. The process shows promise for industrial application

Development of recycling method at cemented carbide scraps was researched. Some properties of recycled cemented carbides were investigated. Recycled WC fine powder suffered the surface oxidation. Therefore it was necessary to be done by reduction treatment at 1073K-3.6ks under hydrogen atmosphere. When sintering condition at 1673K-3.6ks was treated under vacuum condition, it gained the deflective strength of about 90%, and gained hardness and sintering density about same value compared with commercial alloys. As a result, it was able to recycle only by 7 processes.

자연식생 재현을 파악하기 위하여 리싸이클링에코녹화공법을 이용한 장흥다목적댐 배면부에 모니터링 시험구를 선정하였다. 모니터링 시험구는 2004년 5월에 설치하였고, 2004년 5월부터 2005년 10월까지 4차례 걸쳐 식물상, 식물군집구조, 자연이입종, 고사율을 모니터링 하였다. 우드칩 멀칭 후 출현 종 수 감소와 함께 출현식물의 도시화지수가 감소하여 자연성은 증진되었으며, 덩굴식물의 세력은 확장되었다. 낙엽활엽수군락에서 자연이 입종 수가 가장 많았고, 식재수목의 고사율도 높았다.

무전해 PCB 도금 공정 수세액을 분리막으로 처리하여 투과수는 공업용수로 재사용하고 유가금속인 금(Au)을 회수하는 방법에 관하여 연구하였다. 역삼투 분리막 테스트 셀을 이용하여 수세액 처리에 적합한 분리막을 선정하였으며 scale-up을 위한 나권형 모듈 투과 실험을 실시하였다. 먼저, (주)새한에서 생산되는 RO-TL(tap water, low pressure), RO-BL(brackish water, low pressure), RO-normal(for water purifier)막으로 투과실험하였으며 그 중 RO-TL막이 soft etching, 촉매 및 Ni 수세액 처리에 우수한 것으로 판명되었다. 따라서 RO-TL막으로 제작한 나권형 가정용 정수기 모듈로 7bar, 25℃에서 scale-up 실험을 수행하였다. Au수세액의 투과 유속은 약 30 LMH로서 가장 높았으나 Au 제거율이 80% 미만이었다. Pd, Ni 및 soft etching 수세액의 투과유속은 각각 약 22, 17, 10 LMH 정도이며 Pd의 제거율은 85% 이상, Ni 및 Cu 제거율은 97% 이상이었다. 또한 Au, Ni 및 Cu 이온이 함유된 수세액 중 유가금속인 Au를 선택적으로 회수하기 위하여 NF막을 사용하였다. Au수세액 중 Ni 및 Cu 이온은 대부분 제거되었으며 투과액 중에 Au이온이 81.9% 존재하였고 계속하여 RO-TL막으로 Au를 농축 회수하였다. 마지막으로 4"직경의 NF 및 RO-TL 나권형 모듈을 연속적으로 사용하여 Au를 효과적으로 회수할 수 있음을 재확인하였다.인하였다.

The purpose of this study was to develop a recycling system for ozone off-gas. Although the ozone transmission rate of the injector method differs slightly depending on the ozone injection rate, it reaches approximately 99%, which is very high. During the increase in water inflow to the ozone recycling system from 2 L/min to 10 L/min, the average ozone recycling rate was 99.4% at a 1 ppm ozone injection rate, 98.6% at a 2 ppm ozone injection rate, 98.1% at a 3 ppm ozone injection rate. Ozone treatment facility operating costs can be divided into the costs of pure oxygen production, ozone production, and maintenance. The annual operating costs of ozone treatment facilities in Korea are estimated to be approximately 38.9 billion won. The annual savings are estimated to be approximately 5.8 billion won when the ozone transfer rate of the diffuser method, which is mostly employed in domestic water treatment plants, is 85% and 15% of the ozone is recycled.

다양한 산업 활동에 따라 배출되는 폐기물 중 낮은 경제성 때문에 재활용되지 못하고 매립되는 폐기물이 증가하고 있다. 폐자원의 재활용 방향성을 확대하고 미처리폐기물의 매립 제로화를 추진하여 2035년 까지 폐기물 매립처분 비율을 1.0%까지 감소시키고자 목표를 설정하였다. 국내 전체 폐기물의 매립처분 비율은 2015년도 기준 9.2%(38,308 ton/day)이다. 이중 사업장배출시설계폐기물이 약 62%(23,577 ton/day)로 가장 높은 비율을 차지하고 있다. 무기성폐기물 중 열적처리 잔재물류의 매립량은 10,637 ton/day로 사업장배출시설계폐기물 매립량의 45.1%을 차지하고 있는 것으로 조사되었다. 본 연구에서는 강열감량, 총유기탄소, XRF 등의 분석을 통하여 무기성폐기물의 물질 특성을 나타내었다. 사업장 제품 특성 및 배출 폐기물의 성상에 따라 성분 함량이 상이함을 확인할 수 있었다. XRF분석결과, 광재는 Fe 성분 비율이 2.3~69.9%로 나타났으며 대부분 Fe로 형성되어 있음을 확인할 수 있었다. 분진의 경우 Mg, Al, Si, Ca 등 다양한 형태의 원소들이 함유되어 있었으며 Ca 성분이 0.5~57.5%로 높게 나타났고 Si 성분이 1.3~55.6%로 나타났다. 연소재의 경우 대부분 Si, Ca 성분으로 이루어져 있었으며, Si는 3.6~57.1%, Ca는 4.1~55.9% 함유되어 있음을 확인할 수 있었다.

전자산업의 발달로 printed circuit board (PCB)와 같은 구리를 함유한 부품의 수요는 증가하고 있으며, 이를 제조 및 가공하는 과정에서 염산 및 질산과 같은 강한 산이 사용되며, 이 때 발생되는 폐산은 많은 양의 구리를 함유한 채 폐기처분된다. PCB 제조 기기의 구리 석막을 제거하기 위하여 사용되는 세척용 질산은 사용 후, 구리를 3~8% 수준으로 함유하고 있으며, 현재 발생되는 폐질산은 가성소다(NaOH)나 소석회(Ca(OH)2)를 이용하여 중화한 후 처리되고 있는 실정이다. 본 연구에서는 폐산 내 존재하는 구리를 탄산구리(CuCO3) 형태로 침전시키기 위하여 소다회(Na2CO3) 및 소석회(Ca(OH)2)를 이용하여 구리를 중화･침전시켜 회수하고, 이를 재자원화하기 위한 금속소재(금속 구리, 산화구리 등)로 제조하는 것을 목적으로 한다. 폐질산으로부터 탄산구리(CuCO3)를 회수하기 위한 반응인자로 사용 약품의 혼합비, 사용량, 침전 pH, 반응 온도를 달리하여 구리의 회수율을 최적화하였다. 또한, 회수된 탄산구리를 고온에서 산화시켜, X-ray diffraction(XRD)을 통한 결정성을 확인하고, 탄산구리를 폐염산에 용해시켜, 철 치환반응을 통한 금속구리를 제조하였다. 구리를 5% 함유한 폐질산으로부터 99.8% 이상 구리를 회수한 최적 조건은 소다회:소석회 혼합비 1:2에서, 혼합약품 사용량 300 g/kg, 침전 pH 6.5, 반응온도 70℃로 도출되었다. 또한, XRD 분석을 통한 고온산화조건은 1,100℃에서 산화구리(CuO) 전환률 99.9%를 나타냈으며, 폐염산에 용해시켜, 철 치환반응을 통해 제조된 금속구리의 구리 순도는 99.8%로 나타났다. 본 연구를 통하여 현재 중화처리 후, 매립되는 구리 자원의 재활용 방안을 도출하였으며, 이를 사업화하기 위하여 추가적 연구가 필요할 것으로 예상된다.

Slag and coal ash were selected to evaluate the recyclability of waste generated during the heat treatment processes. A list of waste types and recyclable types of the two wastes were identified. A recycling environmental hazardous assessment was reviewed step by step. In addition, the hazardous properties of slag and coal ash were investigated, and the chemical components, leaching, and content of harmful substances in the waste were analyzed. The two selected wastes were classified as general wastes. As a result of chemical analysis with XRF, the two wastes did not produce toxic gases in contact with water and show leaching toxicity from the analysis of harmful substances. In addition, waste is often brought into contact with the soil when recycled, so the content of slag and coal ash is analyzed and compared with the 2 region standard of soil; two samples were within the standard. Therefore, the surveyed wastes can be recycled in non-matrix contact types and the recycling purpose and method permitted by the new law is excluded from the recycling environmental hazardous assessment. However, to recycle wastes for new uses, the recycling environmental hazardous assessment is required.

Biological nitrogen removal is generally accomplished by aerobic nitrification coupled with anoxic denitrification. Many commercial wastewater treatment plants (WWTPs) use external carbon source, such as methanol, to support heterotrophic denitrification process. Using organic wastes as an alternative to commercial carbon sources could thus be beneficial by saving the expense as well as reducing the environmental footprint. Here we report a full-scale (treating 2300 m3 wastewater/d) WWTP that previously utilized a butanediol-based organic waste as the sole external carbon source, which diversified the carbon sources by using a second organic waste generated from food waste recycling. Process parameters were extensively monitored for seven months at all biological unit processes, the aerobic and anoxic tanks, as well as the recirculation flow. Bacterial community structures were analyzed at anoxic tank using next-generation sequencing. The WWTP showed a stable nitrogen-removing performance over the seven months period. The estimated COD/N utilization ratio for food waste-recycling wastewater (FRW) was near 30. The bacterial populations significantly shifted during the operation. Lactobacillaceae and Prevotellaceae were the major bacterial families in the FRW, whereas the denitrification tank was populated by many families including Saprospiraceae, Nannocystaceae, Chitinophagaceae, Eubacteriaceae, and Rhodocyclaceae. Detailed discussion of the results will be presented at the conference.