김용성 Yong-seong Kim , 김찬양 Chanyang Kim , 현승훈 Seunghun Hyun

DOI:10.9786/kswm.2016.33.3.207

Abstract

In the last 10 years, the annual number of published journal articles on biochar has increased dramatically. In addition, biochar research in South Korea has received much attention in a variety of research fields. The objectives of this study were to determine biochar research trends using bibliometric analysis methods and to suggest future research directions in South Korea. The data used in this study were compiled from online international and domestic scientific articles from 2010 to 2015. Annual production, institutes, main journal titles, research fields and frequency of keywords were analyzed to assess current research trends. As a result, biochar research in South Korea was found to be initially 10 years behind the global trend, but in 8th place globally in terms of published articles as of 2015. Future research on the long-term ecological/environmental effects of land-applied biochar and factory-scale production systems is necessary to promote practical use of biochar in South Korea.

Key Words

Biochar, Bibliometric analysis, Research trend, South Korea

고아람 Ah-ram Ko , 이우근 Woo-keun Lee

DOI:10.9786/kswm.2016.33.3.224

Abstract

An insulating brick was developed and evaluated as a potential recycling Waste Limestone (WL) with Melting Slag (MS). We aimed at analyzing the parameters affecting the insulating brick manufacture to enhance the recyclability of WL. In this study, The thermal conductivity, compressive strength and apparent porosity of prepared brick were measured with the addition of aluminum dross and the molar ratio of the alkali activator. The thermal conductivity, compressive strength and apparent porosity were 0.28 W/mK, 2.41 MPa and 44.72% respectively at a mixing ratio of 9.5 : 0.5wt%, 1.5 M SiO₂/Na₂O, 3wt% aluminum dross. Thus, it met the standards of insulating fire bricks (KS L 3301).

Key Words

Waste limestone, Melting slag, Thermal conductivity, insulating block

노다지 Da-ji Noh , 서용수 Yong-soo Seo , 이제근 Jea-keun Lee

DOI:10.9786/kswm.2016.33.3.230

Abstract

In this study, GC-MS linked with an automatic thermal desorber was used to quantitatively analyze the odorous and volatile compounds in the gas emitted from a sewage sludge drying facility. In addition, the removal characteristics of these compounds were investigated by using a pilot-scale packed bed wet scrubber. A quantitative analysis for 58 odorous and volatile compounds in the gas was successfully achieved with GC-MS and GC-FPD. The a quantitative analysis revealed the major odorous compounds were hydrogen sulfide and acetaldehyde. In addition, D-type siloxane compounds such as octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), were quantitatively measured. The concentrations of siloxane compounds measured in the gas were in the range of 4.54- 7.36 ppmv, higher than those in landfill gas. The average removal efficiency of the odorous and volatile compounds in a wet scrubber was 67.37%. D4, D5, and D6, which are hydrophobic compounds, were also removed by as much as 50.68%, 44.56%, and 70.26%, respectively.

Key Words

Sewage sludge drying facility, Odorous and volatile compounds, Siloxane, Removal efficiency, Wet scrubber

김재우 Jae Woo Kim , 박상숙 Sang Sook Park

DOI:10.9786/kswm.2016.33.3.239

Abstract

In this study, the COSLIF method for the pretreatment of lignocellulose biomass was employed to overcome the disadvantages of the conventional DA method. When lignocellulose biomass was hydrolyzed by the COSLIF method, dried rice straw produced glucose corresponding to 60.1%, while herbal medicine waste was found in 25.2%. The optimum conditions of the COSLIF method for the pretreatment of biomass were as follows: 84% phosphoric acid, 50℃, and 45 min. The COSLIF method for corn stover showed more lignin-removal characteristics than the DA method. Glucan digestibility in the COSLIF method at a high enzyme dosage was found to be 97% and at least 90% in 12 h and 24 h, respectively, while in the DA method, it was 84% in 72 h. In addition, at a low enzyme dosage, glucan digestibility was 93% in 24 h in the COSLIF method and 60% in 72 h in the DA method. This demonstrates that the COSLIF method is more efficient than the DA method.

Key Words

Biomass, Pretreatment, COSLIF (Cellulose solvent-and organic solvent-based lignocellulose fractionation) method, DA (dilute acid) method, Lignocellulose

박수호 Soo-ho Park , 이우범 Woo-bum Lee , 김성욱 Sung-wook Kim , 김종오 Jongo Kim

DOI:10.9786/kswm.2016.33.3.248

Abstract

The objective of this study was to investigate the 16 priority polycyclic aromatic hydrocarbon (PAHs) concentrations and emission sources from the soils of three regions (north, mid-south, and east) in Jeollanamdo. Overall PAH concentrations in the east region were higher than in north and mid-south regions and 9.1 times higher for polluted areas. The results of the emission source study indicated that average Ant/(Ant+Phe) and InP/(InP+BghiP) ratios were 0.15-0.22 and 0.36-0.46, respectively, which indicated dominant pyrogenic sources in the three regions. For the InP/(InP+BghiP) ratio, various emission sources were shown in the east region where petrochemical facilities and oil storage tanks have been operated.

Key Words

Industrial complex, Jeollanamdo, Soil, PAHs, Pyrogenic, Petrogenic

김병환 Byung-hwan Kim , 강필선 Pil-sun Kang , 유승관 Seung-kwan Yoo

DOI:10.9786/kswm.2016.33.3.257

Abstract

Mineral carbonation is one of the safest permanent carbon dioxide sequestration methods. Carbon Capture & Utilization (CCU) is a process that utilizes available resources by removing carbon dioxide in a method of mineral carbonation. It can be applied to industries producing high carbon dioxide emissions. This study aims to investigate the absorption performance of carbon dioxide at high concentrations. Calcium hydroxide suspension was used as an absorbent. In addition, NaOH and Mg(OH)₂ were used as additives. Carbon dioxide removal efficiency with NaOH increased from 30% to 90% when the additive amount was increased from 1wt% to 3wt%. In the case of Mg(OH)₂, carbon dioxide absorption efficiency was minimal regardless of the additive amount. In addition, the solid byproducts werec onfirmed by X-ray diffraction spectra and SEM images.

Key Words

Mineral Carbonation, CCU, CO₂, Ca(OH)₂

박종은 Jong-eun Park , 전태완 Tae-wan Jeon , 황동건 Dong-gun Hwang , 강영렬 Young-yeul Kang , 정용우 Yong-woo Jeong , 홍수연 Soo-yun Hong , 정성경 Seong-kyeong Jeong , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2016.33.3.265

Abstract

In this study, we looked into the levels and distribution characteristics of harmful substances found in imported coal ash to identify their possible impacts on the environment and human body in the process of recycling and to develop plans for their proper management. To this end, organic pollutants including heavy metals were analyzed from 19 samples of imported coal ash, and their potential impact on the environment was evaluated. To investigate the characteristics of the heavy metal content in the coal ash, a leaching test was conducted, and the result showed that the heavy metal concentrations in the coal ash were far lower than the permitted levels of hazardous substances in designated waste in Korea. In addition, a content analysis showed that the heavy metal content was lower than the level prescribed in the standards for area II levels of soil contamination. Since coal ash is recycled in cement kilns, levels of Pb, Cu, and Cd in the cement kilns were reviewed and compared against permitted levels of those heavy metals in other alternative fuels. Levels of Pb, Cu, and Cd in the coal ash were comfortably within the acceptable limits by Korean standards, but the level of arsenic was close to the limit. Given the fact that arsenic leached from the coal ash recycling process could have an adverse impact on both the environment and the human body, it is therefore necessary to monitor arsenic leaching from coal ash continuously . Levels of other substances that could be contained in coal ash, such as dioxin, PCBs , and PAHs, were also measured. The measurements showed that the levels of these substances were generally low or undetectable; therefore, the environmental impact of organic pollutants from coal ash recycling was considered insignificant.

Key Words

Coal ash, Recycling, Heavy metal, Organic pollutants

이찬희 Chan Hee Lee , 배우근 Wookeun Bae

DOI:10.9786/kswm.2016.33.3.274

Abstract

In this study we conducted a material flow analysis (MFA) of the four major types of waste electrical and electronic equipment (WEEE), namely refrigerators, TV sets, washing machines, and air conditioners, based on the most reliable data available from the Eco-Assurance System, other governmental sources, the literature, a field survey, and interviews. A MFA of six major components, iron, copper, aluminum, plastics, precious metals, and rare metals was also conducted. The estimated total generation of WEEE in 2013 amounted to 401.8 thousand tons, of which 3.8% (or, approximately 5% including printed circuit boards) was exported and 55.0% was recycled. The collection by the formal take-back system occupied 34.6% of the total generation, from which 83.9% was recovered as valuables. The six major components amounted to 299.7 thousand tons, among which 89.8% of iron, 91.4% of copper, 56.0% of aluminum, 27.1% of plastics, 37.1% of precious metals, and 6.2% of rare metals were recovered. A high positive correlation was found between the amount of WEEE flowing into the private recycling business and its economic value. Since the recovery ratio in the private sector was estimated to be much lower, while the potential environmental impact was higher, an optimal strategy was identified to enhance the collection by the public sector. Providing economic incentives should be an effective means to encourage private collection through the formal take-back system.

Key Words

Material flow analysis (MFA), Waste electrical and electronic equipment (WEEE), Formal take-back system, Recovery, Economic incentive

박선오 Seon-oh Park , 엄남일 Nam-il Um , 김우일 Woo-il Kim , 최효현 Hyo-hyun Choi , 윤철우 Chul-woo Yun , 김태희 Tae-hee Kim , 강영렬 Young-yeul Kang , 전태완 Tae-wan Jeon , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2016.33.3.285

Abstract

Recycling technology research in the copper smelting industry is necessary because the recovery of valuable metals from generated waste can offset the cost of raw materials. The cost of imported raw materials, can exert a significant impact on profitability. In order to perform this research review of previous studies about the base characteristics of the target waste was needed. In this study, copper slag and copper alloy smelting slag generated in the process, along with slag, ash, and sludge, were analyzed for particle size, distribution of the waste, physical characteristics, chemical composition, and inclusion of heavy metals. Copper slag and copper alloy particle separation results were able to remove most of the metal pieces that were at least 1 mm in size. In this waste, zinc, copper-containing metal were less than 80%. toxic substances, such as cadmium, arsenic and mercury, were removed by utilizing a hydrometallurgical process. The data suggests that this industry should be able to take advantage of new technologies the recover valuable metals from copper smelting waste.

Key Words

Copper slag, Copper alloy, Copper slag leaching, Copper slag content

정벼리 Byeo Ri Jeong , 윤수혁 Soo Hyuk Yoon , 전영남 Young Nam Chun

DOI:10.9786/kswm.2016.33.3.294

Abstract

This paper assesses the feasibility of producing fuel energy from sewage sludge via four processes: microwave-induced pyrolysis/gasification and conventional pyrolysis/gasification. Both pyrolysis and gasification produced gas, char, and tar. The gas produced for the gasification contained mainly hydrogen and carbon monoxide with a small amount of methane and hydrocarbons (C₂H₄, C₂H₆, C₃H₈). However, the gasification produced higher carbon monoxide instead of the hydrogen. The microwave gasification generated higher heavy tar compared to other processes. As a light tar, benzene generated higher value for both the pyrolysis and gasification. The sludge char showed a vitreous-like texture for the microwave process and a deep crack shape for the conventional heating process. These results indicate that the gas pro-duced from the microwave processes of wet sewage sludge might be usable as a fuel energy source, but this would require removal of the condensable PAH tars. The sludge char produced could also be used as a solid fuel or adsorbent.

Key Words

Microwave pyrolysis, Gasification, Sewage sludge, Energy conversion

최용준 Yong Jun Choi , 유정원 Jeong Won Ryu , 이상락 Sang Rak Lee

DOI:10.9786/kswm.2016.33.3.303

Abstract

This study was conducted to investigate the effects of different carbon sources on the anaerobic fermentation characteristics in the startup phase using the biochemical methane potential test. The treatments for this experiment were combinations of carbon sources (starch, cellulose, and xylan). Anaerobic fermentation was done at 37oC for 18 days with agitation and pH, ammonia nitrogen, volatile solids reduction, gas production, methane content, and methane production were investigated at 0, 1, 2, 3, 4, 5, 7, 9, 12, 15, and 18 days after incubation in triplicate. In the experiment, the pH was changed depending on the characteristics of the carbon source. The ammonia nitrogen concentration was the highest in the starch-treated group at 7, 12, and 15 days after incubation (P < 0.05). Cumulative volatile solids reduction was the highest in the cellulose-treated group at 18 day after incubation (P < 0.05) and cumulative gas production was higher in the cellulose-treated group than for other two treatments at 18 day after incubation (P < 0.05). Methane content was the lowest in the xylan-treated group at 18 days after incubation (P < 0.05). Cumulative methane production was higher in the xylan-and cellulose-treated group than in the starch-treated group at 18 days after incubation (P < 0.05). In this study, the carbon sources had significant effects on anaerobic fermentation characteristics; especially, the carbon source was shown to have a positive effect on the operation time and hydraulic retention time for the anaerobic digestion startup phage. Therefore, carbon sources should be considered systematically for efficient anaerobic digestion of organic waste.

Key Words

Carbon sources, Anaerobic digestion, Fermentation characteristics, Methane potential

이윤희 Yunhee Lee , 어성욱 Seong-wook Oa

DOI:10.9786/kswm.2016.33.3.314

Abstract

The dewaterability of pig manure by heat pre-treatment was evaluated in this study. The specific resistance coefficient, a dewatering characteristic, was measured by time to filtration (TTF) test. The experimental conditions were set for heat treatment: 15, 30, 60, and 120 min at 120 ± 1℃ and 16, 30, and 60 min at 135 ± 1℃, respectively. The specific resistance coefficient of pig manure was found to be 9.204 × 10¹¹m/kg before treatment, and it gradually decreased with high temperature and long treatment time. Moisture content was decreased from 88% to 77% by heat pre-treatment, and its efficiency was better than mechanical solid-liquid separation with chemical addition. In addition to increased dewaterability, TOC (Total Organic Carbon) concentration was decreased for about 15-42%. Nitrogen concentration was also decreased due to conversion of NH₄⁺-N to NH₃ gas by increased treatment temperature. Consequently, heat pre-treatment was effective for decreasing moisture content and organic matters, and it could have potential for nitrogen recovery.

Key Words

Dewaterability, Heat pre-treatment, Moisture content, Pig manure, Specific resistance coefficient