우라늄 변환시설의 라군 슬러지에 함유된 질산염의 안정적 처리를 위해 물 첨가 용해를 실시한 뒤, 여과 케이크의 안정화 특성에 대하여 알아보았다. 물 용해에 의해 대부분의 질산염은 고농도 질산염 용액으로 제거되었으므로, 여과 케이크의 열분해는 에서 하나의 단계로 수행하였다. Muffle furnace를 이용하여 에서 5시간동안 여과 케이크의 열분해를 실시한 결과 라군 1 슬러지에 포함된 U은 의 열분해와 함께 의 형태로 안정화 되었다. 라군 2 열분해 잔류물의 경우에는 열분해 시 생성된 CaO가 냉각과정에서 수분과 반응하여 로 전환되는 것을 TG/DTA 분석과 XRD 분석을 통해 확인할 수 있었지만, 처분장에서 대기중 노출이나 지하수의 침출 등에는 안정한 화합물로 알려져 있으므로, 특별한 첨가제의 첨가 없이 단순 열분해 후 처분이 가능할 것으로 판단된다.

In the present study, the focus is on the analysis of carbothermal reduction of oxide powder prepared from waste WC/Co hardmetal by solid carbon under a stream of argon for the recycling of the WC/Co hard-metal. The oxide powder was prepared by the combination of the oxidation and crushing processes using the waste hardmetal as the raw material. This oxide powder was mixed with carbon black, and then this mixture was carbothermally reduced under a flowing argon atmosphere. The changes in the phase structure and gases discharge of the mixture during carbothermal reduction was analysed using XRD and gas analyzer. The oxide powder prepared from waste hardmetal has a mixture of . This oxide powder reduced at about , formed tungsten carbides at about , and then fully transformed to a mixed state of tungsten carbide (WC) and cobalt at about by solid carbon under a stream of argon. The WC/Co composite powder synthesized at for 6 hours from oxide powder of waste hardmetal has an average particle size of .

Emission of hazardous and volatile organic chemicals from solid waste landfill site was become to important issue because of environmental pollution and health risk by such chemicals. Laboratory batch and continuous experiments were conducted respectively to elucidate isothermal sorption behaviors and transport phenomena(by gas through unsaturated solid waste layer) in wet solid waste-gas system. Source separated and size reduced refuse(bulky waste) and incinerated ash were used after controlling water content, and trichloroethylene(TCE) was chosen among many such chemicals because of it's generality among those man-created pollutants. Isothermal TCE sorption equilibria wet solid waste-gas system can be described in linear equation and partition coefficient in this system can be estimated approximately by the simple equation derived from schematic structure of the system. Transport equation modified by instantaneous equilibrium sorption fraction and kinetic sorption rate(overall mass transfer capacity coefficient) simulated well the column experiment results.

Zeolite material having XRD peaks of Na-A zeolite in the 2θ range of 7.18 to 34.18 can be synthesized from the waste catalyst using a fusion/hydrothermal method. The adsorption rate of Mn ions by a commercial Na-A zeolite and the synthesized zeolitic material increased as the adsorption temperature increased in the range of 10 ~ 40℃. The adsorption of Mn ion were very rapid in the first 30 min and then reached to the equilibrium state after approximately 60 min. The adsorption kinetics of Mn ions by the commercial Na-A zeolite and the zeolitic material were found to be well fitted to the pseudo-2nd order kinetic model. Equilibrium data by the commercial Na-A zeolite and the zeolitic material fit the Langmuir, Koble-Corrigan, and Redlich-Peterson isotherm models well rather than Freundlich isotherm model. The removal capacity of the Mn ions by the commercial Na-A zeolite and the zeolitic material obtained from the Langmuir model was 135.2 mg/g and 128.9 mg/g at 30℃, respectively. The adsorption capacity of Mn ions by the synthesized zeolitic material was almost similar to that of commercial Na-A zeolite. The synthesized zeolitic material could be applied as an economically feasible commercial adsorbent.

This study was carried out to examine the improvement plan by analyzing the characteristics of imported wastes, operation rate, and benefits of energy recovery for incineration facilities with a treatment capacity greater than 50 ton/ day. The incineration facility capacity increased by 3,280 tons over 15 years, and the actual incineration rate increased to 2,783 ton/day. The operation rate dropped to 76% in 2010 and then rose again to 81% in 2016. The actual calorific value compared to the design calorific value increased by 33.8% from 94.6% in 2002 to 128.4% in 2016. The recovery efficiency decreased by 29% over 16 years from 110.7% to 81.7% in 2002. Recovery and sales of thermal energy from the incinerator (capacity 200 ton/day) dominated the operation cost, and operating income was generated by energy sales (such as power generation and steam). The treatment capacity increased by 11% to 18% after the recalculation of the incineration capacity and has remained consistently above 90% in most facilities to date. In order to solve the problem of high calorific value waste, wastewater, leachate, and clean water should be mixed and incinerated, and heat recovery should be performed through a water-cooled grate and water cooling wall installation. Twenty-five of the 38 incineration facilities (about 70%) are due for a major repair. After the main repair of the facility, the operation rate is expected to increase and the operating cost is expected to decline due to energy recovery. Inspection and repair should be carried out in a timely manner to increase incineration and heat energy recovery efficiencies.

Over the past two decades, the options for solid waste management have been changing from land disposal to recycling, waste-to-energy, and incineration due to growing attention for resource and energy recovery. In addition, the reduction of greenhouse gas (GHG) emission has become an issue of concern in the waste sector because such gases often released into the atmosphere during the waste management processes (e.g., biodegradation in landfills and combustion by incineration) can contribute to climate change. In this study, the emission and reduction rates of GHGs by the municipal solid waste (MSW) management options in D city have been studied for the years 1996-2016. The emissions and reduction rates were calculated according to the Intergovernmental Panel on Climate Change guidelines and the EU Prognos method, respectively. A dramatic decrease in the waste landfilled was observed between 1996 and 2004, after which its amount has been relatively constant. Waste recycling and incineration have been increased over the decades, leading to a peak in the GHG emissions from landfills of approximately 63,323 tCO2 eq/yr in 2005, while the lowest value of 35,962 tCO2 eq/ yr was observed in 2016. In 2016, the estimated emission rate of GHGs from incineration was 59,199 tCO2 eq/yr. The reduction rate by material recycling was the highest (-164,487 tCO2 eq/yr) in 2016, followed by the rates by heat recovery with incineration (-59,242 tCO2 eq/yr) and landfill gas recovery (-23,922 tCO2 eq/yr). Moreover, the cumulative GHG reduction rate between 1996 and 2016 was -3.46 MtCO2 eq, implying a very positive impact on future CO2 reduction achieved by waste recycling as well as heat recovery of incineration and landfill gas recovery. This study clearly demonstrates that improved MSW management systems are positive for GHGs reduction and energy savings. These results could help the waste management decision-makers supporting the MSW recycling and energy recovery policies as well as the climate change mitigation efforts at local government level.

This study examined the potentials for greenhouse gas reduction by material recovery and energy recovery from municipal solid waste between 2017 and 2026 in Daejeon Metropolitan City (DMC), which is trying to establish a material-cycle society by constructing a waste-to-energy town by 2018. The town consists of energy recovery facilities such as a mechanical treatment facility for fluff-type solid refuse fuel (SRF) with a power generation plant and anaerobic digestion of food waste for biogas recovery. Such recycling and waste-to-energy facilities will not only reduce GHGs, but will also substitute raw materials for energy consumption. The emissions and reduction rate of GHGs from MSW management options were calculated by the IPCC guideline and EU Prognos method. This study found that in DMC, the decrease of the amount of MSW landfilled and the increase of recycling and waste-to-energy flow reduced GHGs emissions from 167,332 tonCO2 eq/yr in 2017 to 123,123 tonCO2 eq/yr in 2026. Material recycling had the highest rate of GHG reduction (-228,561 tonCO2 eq/yr in 2026), followed by the solid refuse fuels (-29,146 tonCO2 eq/yr in 2026) and biogas treatment of food waste (-3,421 tonCO2 eq/yr in 2026). This study also shows that net GHG emission was found to be -30,505 tonCO2 eq in 2017 and -105,428 tonCO2 eq, indicating a great and positive impact on future CO2 emission. Improved MSW management with increased recycling and energy recovery of material waste streams can positively contribute to GHGs reduction and energy savings. The results of this study would help waste management decision-makers clarify the effectiveness of recycling MSW, and their corresponding energy recovery potentials, as well as to understand GHG reduction by the conversion.

본 연구에서는 선행 연구를 통해 고온전이반응(HTS: High Temperature Shift reaction)에서 높은 활성 및 안정성을 나타내는 Fe-Al-Cu 촉매에 대한 연구를 수행하였다. 연구실 규모(3gcatal./batch)에서 공침법으로 제조된 Fe-Al-Cu 촉매 시스템을 대용량 규모로 스케일-업하기 위해 연구실 규모와 대용량 규모로 제조된 Fe-Al-Cu 촉매의 다양한 물리-화학적 특성을 XRD, H2-TPR, BET, N2 흡착 분석 등으로 분석하였다. 배치당 제조량을 달리하여 제조된 Fe-Al-Cu 촉매는 촉매반응장치를 통해 정량적으로 성능을 비교 평가하였으며 제조된 촉매의 성능을 입증하기 위해 상업용 Fe-Cr 촉매와 성능을 직접 비교하였다. 특히, 선행 연구를 통해 최적화된 고활성 및 고안정성 Fe-Al-Cu 촉매를 대용량 규모로 제조하여 제조량에 따른 성능 변화와 물리화학적 특성간의 상관관계에 대해 규명하였다.

유엔기후변화협약(UNFCC)은 온실가스 배출통계의 중요성을 강조함에 따라 모든 당사국들은 국가 온실가스 인벤토리 산정 보고서를 제출할 의무를 명시하고 있다. 국가 온실가스 인벤토리 분야에는 폐기물 분야도 포함되어 있으며, 특히 메탄배출량의 상당량을 차지하는 폐기물매립지에 대한 온실가스 배출량 산정은 매우 중요시되고 있다. 그럼에도 불구하고 국내 폐기물매립지는 아직까지 GPG(Good practice guidance) 2000에 기반하여 온실가스 배출량을 산정하고 있어 2006 IPCC 가이드라인을 기준으로 매립지 온실가스 배출량을 산정하고 있는 미국과 EU 국가 등과 비교하여 배출량 산정의 정확도가 낮은 문제점을 나타내고 있다. 이에 본 연구에서는 GPG 2000과 2006 IPCC 가이드라인(Tier 1, 2)을 기반으로 국내 폐기물매립지의 온실가스 배출량을 산정 및 비교함으로써 폐기물매립지 온실가스 배출량 산정방법의 문제점 및 개선방향을 제시하고자 하였다. 각 방법별 폐기물매립지의 국가 온실가스 배출량 산정 결과, 2015년 기준으로 2006 IPCC Tier 1의 배출량은 10,885 Gg CO2eq,로 가장 높게 나타났으며, 다음으로 2006 IPCC Tier 2(9,443 Gg CO2eq,), GPG 2000(7,727Gg CO2eq)순으로 나타났다. GPG 2000과 2006 IPCC 가이드라인 모두 FOD 모델을 기반으로 하고 있기 때문에 연도별 배출량 증감은 비슷하였으나 GPG 2000은 매립폐기물 전부를 하나의 단일 성상으로 가정한 반면 2006 IPCC에서는 폐기물 성상별로 배출계수를 적용하도록 하고 있어 배출량의 차이가 발생하였다. 다만 2006 IPCC에서는 국가 배출계수의 적용을 권고하고 있어 향후 이에 대한 지속적 개발 및 검증이 이루어져야 할 것이다.

This study carried out first a component survey on the domestic waste shipped into a waste disposal facility in B city, and then heavy metal analysis of each component according to the SRF standards. Based on this, this study explored the problems with domestic waste and measures to improve them. The results are as follows. The result of the survey of physical components show that paper accounted for the largest proportion with 20.5 %~59.9 %, metals (including batteries) among incombustibles accounted for 0.0~8.3 %, other inorganic substances, glass and ceramics accounted for 0.0~43.7 % and 0.0 %~19.6 % respectively. However, the proportion of coated viny and plastics, which have high lead and cadmium content, was rather high with 2.9 %~30.9 %. This suggests the possibility that actual concentration of lead and cadmium within SRF is likely to be higher. Among the 15 components contained in the waste brought into the waste disposal facility, 10 components (food waste, textiles, vinyl, plastics, wood, rubber and leather, paper, metals, electronic substrates, and nail polish) were analyzed according to assay samples (approximately 0.1 g and 0.3 g). The result of analysis shows that the amount of Cd and Pb detected in coated vinyl for 0.109 g of assay sample was 98.6 mg/kg and 20.6 mg/kg respectively; 117.0 mg/kg and 29.0 mg/kg respectively for 0.313 g of assay sample. This is high contents exceeding the Cd standard. As for wooden component, the amount of Pb was 480.0 mg/kg for 0.3 g of assay sample. This suggests that there always exists the possibility of exceeding the exposure level of heavy metals (Cd and Pb) in SRF as long as coated wood and vinyl·plastics with high contents of Pb and Cd are shipped into the waste disposal facility; and the local government and the residents need to work hard to improve the situation including development of the machine to sort electronic substrates and batteries for separate collection of the waste of coated vinyl and plastics within domestic waste.

The use of mechanical treatment (MT) for preparing solid refuse fuel (SRF) using municipal solid waste has been growing in Korea. One of the problems with using this treatment measure is the generation of residual waste from the MT, which will not be contained in the SRF. Most of this waste will be dumped into landfill instead of being used for the production of SRF. Much of the waste will be organic portions originating from food and biodegradable wastes. Consequently, the organic portion dumped into the landfill generates methane gas, which is a strong greenhouse gas. In this paper, the waste from MT was investigated directly at the MT facility located at Su-Do-Kwon landfill site to develop proper treatment measures to avoid disposing of the MT waste in landfill, which is prohibited in Germany and England.

Depending on the steam pressure and temperature balance, it is possible to increase the power generation efficiency of the steam turbine by increasing the heat loss of the turbine by increasing the temperature and pressure. As the high temperature and high pressure increase, the boiler main steam amount is reduced by about 10%, but the increase rate of the heat drop is larger than the decrease rate of the steam flow rate, leading to improvement of power generation efficiency. Utilizing the US Department of Energy Steam Turbine Calculator, we calculated the electricity produced by steam temperature and pressure changes. In this study, the steam temperature was increased from 50℃ to 500℃ at the steam temperature of 20 kg/cm²×300℃, and increased by 10 kg/cm² at the pressure of 20 kg/cm² at the pressure of 60 kg/cm² to investigate the changes in electricity production. Electricity production increased with increasing temperature and pressure. The electricity production was increased by 40.11% at 40 kg/cm²×400℃ and 75.56% at 60 kg/cm²×500℃ compared to the standard condition of 20 kg/cm²×300℃ for comparison.

Energy can be reduced by reducing the exhaust gas temperature at the catalyst inlet and reducing or not using the amount of steam to reheat the exhaust gas. At this time, it is a method to improve the power generation efficiency by using the saved energy for power generation. When the exhaust gas temperature at the inlet of the catalytic reaction tower is operated at about 210℃, it is necessary to increase the temperature of the flue gas downstream of the bag filter at 165℃ to 45℃ to 210℃ required for the catalytic reaction. In the case of low temperature catalyst application, the temperature required for the catalytic reaction tower may be 185℃ and the temperature may be raised only 20℃. Therefore, the amount of steam for heating can be reduced. If the exhaust gas temperature of the bag filter inlet can be increased to 190℃, it can be combined with the low-temperature catalyst to reduce the energy consumed by removing exhaust gas ash. On the other hand, since the high-pressure steam is used as the heat source for reheating the exhaust gas, the reheating temperature is limited. According to such conditions, the exhaust gas temperature at the inlet of the catalytic reaction tower is often designed at about 200 to 220℃.

우리나와 같이 삼면이 바다인 지역은 연안 해역에서의 대규모 어업활동 및 산업화로 인하여 해상 및 해저의 침적 폐기물, 패각류, 퇴적 오염물 등 해양폐기물 발생량의 증가로 인하여 인류의 정화조라 표현되던 해양은 오염이 날로 심각한 상태에 이르고 있다. 본 연구는 해변에 밀려온 해안폐기물을 대상으로 고형연료 활용 가능성 및 활용 보관, 이동성을 확보하기 위한 펠렛 성형 조건을 분석하였다. 해안폐기물은 그물류, 목재류 등 높은 가연성 물질로 고에너지 고형연료 가능성이 높다. 이를 압축성형을 통한 펠렛 고형연료 생산을 위한 강도별 성형 특성을 분석하였으며, 특히, Polyethylene계 해안폐기물은 펠렛 성형, 형태의 유지 등의 평가를 통해 성형 가능성이 높은 반면 Nylon계 해안폐기물은 성형 형태 유지의 어려움이 있다고 판단된다. 해안폐기물이 고형연료 성형시, Polyethylene는 성형바인더 역할을 수행하여, 압축강도는 350 kg/cm² 이상에서 성형 및 형태 유지가 용이한 조건을 나타냈다. 이렇게 생산된 해안폐기물 고형연료는 높은 Carbon 함량 및 휘발분 함량 등으로 저위발열량은 7,000 kcal/kg이상을 나타냈다.

폐기물매립지에서 함수율은 폐기물의 분해속도뿐만 아니라 폐기물의 분해율에도 영향을 미치는 것으로 알려져 있으며, 이에 매립지 내부의 수분을 인위적으로 증가시켜 매립가스 발생량을 증대시키는 bioreactor 공법이 연구되고 있다. 따라서 향후에는 국내외 매립가스 자원화를 계획 및 진행하고 있는 폐기물매립지를 대상으로 bioreactor 공법이 적용될 것으로 예상되며, 이를 위해 매립지 내부의 함수율 변화에 따른 매립가스 발생특성이 예측되어야 할 것이다. 그러나 기존 연구들에서는 실내실험 및 현장 실증실험을 통하여 bioreactor 공법 적용에 따른 조기안정화 및 매립가스 발생량 증대 효과만을 나타내었을 뿐 함수율 변화가 폐기물의 분해도 및 분해속도에 미치는 영향을 수치적으로 나타내지 않아 bioreactor 공법 적용에 따른 정확하고 신뢰성 있는 매립가스 발생량 예측이 어려운 점이 있다. 이에 본 연구에서는 매립지 내부에서의 함수율 변화가 메탄발생 특성에 미치는 영향을 평가하여 향후 함수율 변화에 따른 메탄발생량 및 발생속도 예측의 기초자료로 이용하고자 하였다. 시료는 가연물 중 매립지에 가장 높은 비율로 매립되는 종이를 대상으로 하였다. 각 반응조별 초기 함수율은 10%, 20%, 30%, 40%, 50%로 설정하였으며, 초기함수율 10~40%의 반응조들은 가스발생이 중지되었을 때 함수율을 10%씩 증가시켜 최종적으로는 모든 반응조의 함수율이 50%에 도달하도록 실험을 진행하였다. 실험결과 메탄발생이 최초 중지되는 시점의 각 반응조별 메탄발생 비율은 50% 반응조 대비 10%는 0.4%, 20%는 0.8%로 메탄발생이 매우 미미하였으며, 30%는 6.5%, 40%는 28.9%로 매우 적은 메탄발생 비율을 나타내었다. 이후 각 반응조마다 메탄발생이 중지되는 시점에 함수율을 10%씩 증가시켜 모든 반응조의 최종 함수율이 50%가 되도록 하였으며, 실험 종료 후 메탄발생 비율은 초기함수율 50% 대비 10%는 3.5%, 20%는 7.0%, 30%는 25.1%, 40%는 49.6%로 나타났다. 이론적으로는 초기 함수율이 낮아도 최종 함수율이 동일하면 유기물의 분해속도는 달라도 최종 함수율이 나타내는 메탄발생량과 동일한 값을 나타내어야 하나 초기함수율 10~40% 반응조 모두 초기함수율 50%가 나타내는 메탄발생량에 훨씬 못미치는 메탄발생량을 나타내었다. 따라서 메탄발생량과 연관하여 초기함수율은 매우 중요 인자이며, 메탄발생이 중지되는 시점에 수분을 추가로 주입하면 메탄발생이 다시 시작되나 최종 메탄발생량은 초기 함수율이 낮을수록 크지 않을 것으로 판단된다.

Solid waste management is currently a topic of concern, particularly in the protection of humans and the environment from toxic pollutants and hazardous materials. The importance of solid waste management is recognized at international, national, and community levels. Different agendas have been prioritized and assigned to improve quality of life, productivity, and health, and reduce the burden of pollution. Suitable management of solid waste requires appropriate technology that is affordable, socially accepted, and environmentally friendly. The use of a smart management system involving system dynamics can save energy, money, and labor. System dynamics is a computer-based approach that aids in predicting the behavioral patterns of variables, and correlating dependent and independent variables. The inclusion of system dynamics-based models in solid waste management has recently become more common. In this review, we used system dynamics to determine methods to disentangle solid waste management systems and analyzed different studies on solid waste management using system dynamics in different countries in detail. We also discussed the various software packages that are available for system dynamics and their usefulness for waste management. This review may help in understanding current solid waste management practices using system dynamics.

Emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurnas (PCDFs) in stack gas were analyzed from 21 municipal solid waste incinerators (MSWs) using high resolution gas chromatography equipment with a high resolution mass spectrometer (HRGC/HRMS) in 2015. The concentration of PCDDs/DFs was in the range 0.09 ~ 354.54 pg-TEQ/Sm3 based on the International Toxicity Equivalency Factor (I-TEF) and all MSWs complied with emission standards. The congener distribution of PCDDs/DFs was categorized into one group and two outliers via principal component analysis (PCA). Among the 17 PCDDs/DFs, 1,2,3,4,6,7,8-HpCDD showed the highest mass fraction (20.8%) and 2,3,4,7,8-PeCDF showed the largest TEQ contribution (42.9%).