• Clean Technology
• /
• v.28 no.2
• /
• pp.131-137
• /
• 2022

The semiconductor process currently emits various by-products and unused gases. Emissions containing pollutants are generally classified into categories such as organic, acid, alkali, thermal, and cabinet exhaust. They are discharged after treatment in an atmospheric prevention facility suitable for each exhaust type. The main components of organic exhaust are volatile organic compounds (VOC), which is a generic term for oxygen-containing hydrocarbons, sulfur-containing hydrocarbons, and volatile hydrocarbons, while the main components of alkali exhaust include ammonia and tetramethylammonium hydroxide. The purpose of this study was to determine the combustion characteristics and analyze the NO_X reduction rate by maintaining a direct combustion and temperature to process organic and alkaline exhaust gases simultaneously. Acetone, isopropyl alcohol (IPA), and propylene glycol methyl ether acetate (PGMEA) were used as VOCs and ammonia was used as an alkali exhaust material. Independent and VOC-ammonia mixture combustion tests were conducted for each material. The combustion tests for the VOCs confirmed that complete combustion occurred at an equivalence ratio of 1.4. In the ammonia combustion test, the NO_X concentration decreased at a lower equivalence ratio. In the co-combustion of VOC and ammonia, NO was dominant in the NO_X emission while NO₂ was detected at approximately 10 ppm. Overall, the concentration of nitrogen oxide decreased due to the activation of the oxidation reaction as the reaction temperature increased. On the other hand, the concentration of carbon dioxide increased. Flameless combustion with an electric heat source achieved successful combustion of VOC and ammonia. This technology is expected to have advantages in cost and compactness compared to existing organic and alkaline treatment systems applied separately.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.31 no.1
• /
• pp.69-84
• /
• 2023

Despite the continuous installation and regular inspection of waste treatment facilities, complaints about excessive incineration and illegal dumping stench continue to occur at on-site treatment facilities. In addition, field surveys were conducted on the waste treatment facilities currently in operation (6 type) to understand the waste treatment process for each field, to grasp the main operating factors applied to the inspection. In addition, we calculated the material·energy balance for each main process and confirmed the proper operation of the waste disposal facility. As a result of the site survey, in the case of heat treatment facilities such as incineration, cement kilns, and incineration heat recovery facilities, the main factors are maintenance of the temperature of the incinerator required for incineration and treatment of the generated air pollutants, and in the case of landfill facilities Retaining wall stability, closed landfill leachate and emission control emerged as major factors. In the case of sterilization and crushing facilities, the most important factor is whether or not sterilization is possible (apobacterium inspection).In the case of food distribution waste treatment facilities, retention time and odor control during fermentation (digestion, decomposed) are major factors. Calculation results of material balance and energy resin for each waste treatment facility In the case of incineration facilities, it was confirmed that the amount of flooring materials generated is about 14 % and the amount of scattering materials is about 3 % of the amount of waste input, and that the facility is being operated properly. In addition, among foodwaste facilities, in the case of an anaerobic digestion facility, the amount of biogas generated relative to the amount of inflow is about 17 %, and the biogas conversion efficiency is about 81 %, in the case of composting facility, about 11 % composting of the inflow waste was produced, and it was comfirmend that all were properly operated. As a result, in order to improve the inspection method for waste treatment facilities, it is necessary not only to accumulate quantitative standards for detailed inspection methods, but also to collect operational data for one year at the time of regular inspections of each facility, Grasping the flow and judging whether or not the treatment facility is properly operated. It is then determined that the operation and management efficiency of the treatment facility will increase.

• Journal of agriculture & life science
• /
• v.50 no.2
• /
• pp.95-105
• /
• 2016

This study was conducted to evaluate the effects of nitrate-rich plants extracts on the in vitro rumen fermentation characteristics and rumen methane production. The extracts of nitrate-rich plants, as potato, carrot, chinese cabbage, lettuce and spinach were used in this study. The ruminal fluid was collected from a cannulated Hanwoo cow fed concentrate and timothy in the ratio of 6 to 4. The 20mL of mixture, comparing McDougall's buffer and rumen fluid in the ratio 2 to 1, was dispensed anaerobically 50mL serum bottles containing 0.3g of timothy substrate and extracts of nitrogen-rich plants. The serum bottles were incubated 39℃ for 9, 12, 24, 48 hours. The pH value was decreased by increased incubation times and normal range to 6.31 to 6.96. The dry matter digestibility was significantly(p<0.05) lower in chinese cabbage than in control at 9h incubation time. Ammonia concentration was significantly(p<0.05) lower in potato, chinese cabbage, lettuce than in control and the rumen microbial growth rate was significantly(p<0.05) higher in carrot than in control at 24h incubation time. The concentrations of acetate and propionate was significantly(p<0.05) lower in treatment than in control. The concentration of butyrate was showed a different pattern depending on treatments. Total gas emissions was significantly(p<0.05) lower in chinese cabbage, lettuce, spinach than in control at 12h, 24h incubation time. Methane production was significantly(p<0.05) lower in potato, chinese cabbage, spinach than in control, carbon dioxide production was significantly(p<0.05) lower in treatment than in control. In conclusion, supplementation of the nitrate-rich plant extracts in ruminal fermentation in vitro resulted in decreasing the methane production without adversely affecting the fermentation characteristics. Particularly the chinese cabbage extract was regard as a potential candidate for reducing the methane emission in ruminants.

• Korean Journal of Remote Sensing
• /
• v.39 no.2
• /
• pp.247-253
• /
• 2023

As climate change problem has recently become serious, studies are being conducted to identify carbon dioxide (CO₂) emission dynamics based on satellite data to reduce emissions. It is also very important to analyze spatial patterns by estimating and mapping CO₂ emissions dynamic. Therefore, in this study, CO₂ emissions in the Korean Peninsula from 2013 to 2020 were estimated and mapped. To spatially estimate and map emissions, we use the enhanced vegetation index adjusted nighttime light index, an index that combines nighttime light (NTL) and vegetation index, to map both areas where NTL is observed and areas where NTL is not observed. In order to spatially estimate and map CO₂ emissions, the total annual emissions of the Korean Peninsula were calculated, resulting in an increase of 11% from 2013 to 2017 and a decrease of 13% from 2017 to 2020. As a result of the mapping, it was confirmed that the spatial pattern of CO₂ emissions in the Korean Peninsula were concentrated in urban areas. After being divided into 17 regions, which included the downtown area, the metropolitan area accounted for roughly 40% of CO₂ emissions in the Korean Peninsula. The region that exhibited the most significant change from 2013 to 2020 was Sejong City, showing a 96% increase.

• Korean Journal of Construction Engineering and Management
• /
• v.24 no.6
• /
• pp.24-35
• /
• 2023

Recently, the Ministry of Land, Infrastructure and Transport presented the '6th Construction Technology Promotion Basic Plan' and 'Smart Construction Revitalization Plan (2022.7.20)'. Off-Site Construction (OSC), which involves construction and production of PC (Precast Concrete) and Modular, etc., has advantages in shortening the construction period, reducing costs, improving quality, reducing construction waste, and reducing safety accidents. However, the construction cost is high compared to the traditional RC construction method, which has hindered its utilization and spread. In this study, OSC utilization was improved. An economic analysis indicator and methodology that can support decision-making in the planning and design stages for multi-unit housing were proposed. The factors used in the economic analysis of OSC (based on the PC method) of apartment houses were reviewed. As for the indicators used in the cost and benefit section, 'Construction Period', 'Disaster Occurrence', 'Waste Generation', and 'Greenhouse gas Emission', which reflect the technical advantages of OSC, were derived. In addition, a scenario analysis was conducted based on actual apartment housing case data for the presented economic analysis indicators and benefit calculation standards. The level of benefit that offsets the difference between the existing RC construction method and the construction cost was reviewed. In future studies, it will be necessary to conduct additional case studies to apply the measurement criteria for detailed indicators and supplement the benefit indicators.

• Journal of Korean Society of Disaster and Security
• /
• v.16 no.4
• /
• pp.45-59
• /
• 2023

The global focus on mitigating climate change has traditionally centered on carbon dioxide, but recent attention has shifted towards methane as a crucial factor in climate change adaptation. Natural settings, particularly aquatic environments such as wetlands, reservoirs, and lakes, play a significant role as sources of greenhouse gases. The accumulation of organic contaminants on the lake and reservoir beds can lead to the microbial decomposition of sedimentary material, generating greenhouse gases, notably methane, under anaerobic conditions. The escalation of methane emissions in freshwater is attributed to the growing impact of non-point sources, alterations in water bodies for diverse purposes, and the introduction of structures such as river crossings that disrupt natural flow patterns. Furthermore, the effects of climate change, including rising water temperatures and ensuing hydrological and water quality challenges, contribute to an acceleration in methane emissions into the atmosphere. Methane emissions occur through various pathways, with ebullition fluxes-where methane bubbles are formed and released from bed sediments-recognized as a major mechanism. This study employs Biochemical Methane Potential (BMP) tests to analyze and quantify the factors influencing methane gas emissions. Methane production rates are measured under diverse conditions, including temperature, substrate type (glucose), shear velocity, and sediment properties. Additionally, numerical simulations are conducted to analyze the relationship between fluid shear stress on the sand bed and methane ebullition rates. The findings reveal that biochemical factors significantly influence methane production, whereas shear velocity primarily affects methane ebullition. Sediment properties are identified as influential factors impacting both methane production and ebullition. Overall, this study establishes empirical relationships between bubble dynamics, the Weber number, and methane emissions, presenting a formula to estimate methane ebullition flux. Future research, incorporating specific conditions such as water depth, effective shear stress beneath the sediment's tensile strength, and organic matter, is expected to contribute to the development of biogeochemical and hydro-environmental impact assessment methods suitable for in-situ applications.

• Journal of Environmental Impact Assessment
• /
• v.33 no.1
• /
• pp.30-41
• /
• 2024

The way we work is changing significantly with the rapid development of digitaltechnology, and paper documents are being replaced by electronic documents. However, in accordance with the Enforcement Decree and Enforcement Regulation of the Environmental Impact Assessment Act, the environmental impact assessment report must submit a set number of paper reports to organizations related to the project, and about 42 years have passed since it was submitted as a paperreport. In 2022, the National Institute of Ecology introduced a system to review paperreports as electronic documents in line with the trend of digital transformation. The cost reduction and carbon emission reduction effects of electronic document review were analyzed for 1,398 environmental impact assessments submitted and reviewed in 2022. In addition, a satisfaction survey was conducted targeting type 1 environmental impact assessment companies that were directly affected, and a total of 134 people responded. As a result of analyzing the effect of reviewing electronic documents, costs are reduced by a total of 101,424,900 won per year and carbon emissions are reduced by about 59.7 tons. As a result of the satisfaction survey, 94.8% of the respondents said electronic documentreview was very helpful, and 4.5% said it was helpful. The effectiveness of electronic documentreview was high, with 94.8% of respondents saying it was helpful in economic terms and 91.8% saying it was helpful in reducing work hours. If electronic documents are reviewed through the revisions to the Enforcement Decree and Enforcement Regulation of the Environmental Impact Assessment Act, the implementation of electronic document review is expected to have a ripple effect across the country, not only reducing costs and carbon emissions, but also reducing administrative time and saving storage space. Rapid changes in law and administration are needed to adapt to the digital transformation era.

• Food Science of Animal Resources
• /
• v.27 no.2
• /
• pp.235-243
• /
• 2007

This study was conducted to evaluate the effects of feeding rye silage on growth performance, blood and carcass characteristics in finishing pigs. The total of eighteen($Landrace{\times}Yorkshire{\times}Duroc$) pigs($74.22{\pm}0.71kg$) were used for 49-day assay. Dietary treatments included 1) CON(basal diet), 2) S1(1.66% rye silage) and 3) S2(3.32% rye silage). In growth performance, from 4 to 7 weeks, average daily feed intake(ADFI) in pigs fed CON diet was higher than pigs fed S1 and S2 diets. Through the entire experimental period($0{\sim}7$ weeks), a ADFI in CON and S2 treatments was higher than S1 treatment (p<0.05). Serum cortisol concentration of pigs fed rye silage decreased significantly compared to pigs fed basal diet (p<0.05). The Hunter's $L^*$(lightness) value of loin in the pigs fed S2 diet was higher than that of loin in the pigs fed CON diet(p<0.05). The $b^*$(yellowness) value of loin in the pigs fed S1 and S2 diets were higher than CON treatment(p<0.05). Backfat thickness in CON treatment increased significantly compared to S1 and S2 treatments(p<0.05). Among fatty acid contents of lean meat, the contents of palmitic and stearic acids were significantly higher in CON than others(p<0.05), where as eicosenoic and linolenic acids were the highest in S2 treatment among treatments(p<0.05). Total SFA(saturated fatty acid) was the highest in CON(p<0.05) and S1 and S2 treatments were higher USFA/SFA(unsaturated fatty acid/saturated fatty acid) ratio than CON treatment. In fats, linolenic acid was higher in S2 treatment than those of S1 and CON treatments(p<0.05). Digestibility of dry matter in pigs fed S1 and S2 diets was greater than that of pigs fed CON diet(p<0.05) and S1 treatment was higher than others on digestibility of nitrogen(p<0.05). VFA(volatile fatty acid) emission from focal, measured after 1 day, increased significantly in pigs fed S1 and S2 diets(p<0.05). In conclusions, our results showed that feeding rye silage might be beneficial in decrease of cortisol concentration, hunter's $L^*$(lightness) value and $b^*$(yellowness), fatty acid contents, and nutrient digestibility. However, there should be more study on the relationship between feeding rye silagr and finishing pigs.