이혜성 Hye-sung Lee , 김용진 Yong-jin Kim

DOI:10.9786/kswm.2017.34.6.537

Abstract

Plastic accounts for 60 ~ 80% of all marine litter. Microplastics are plastic pieces that are 5 mm or less in diameter. They can be classified into primary and secondary microplastics. Primary microplastics arise from the manufacturing, and secondary microplastics arise from plastic decomposition by various factors. Both types of microplastics are not only widely distributed in the oceans, but also can adsorb persistent organic pollutants (POPs) and metals. They can be mistaken for food by marine organisms, and the resulting bioaccumulation can have a significant impact on additional ecosystems. In this study, quantitative and qualitative analysis methods for microplastics from the literature were compared and summarized.

Key Words

Microplastic, Organic digestion, Density separation, Quantitative analysis, Qualitative analysis

연진모 Jin-mo Yeon , 황동건 Dong-gun Hwang , 김우일 Woo-il Kim , 김기헌 Ki-heon Kim , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2017.34.6.546

Abstract

In this study, we investigated the distribution of domestic nanomaterials. Zinc oxide (ZnO), titanium dioxide (TiO2), and silver (Ag) nanoparticles, as well as carbon (C) nanotubes, were selected, and their circulation and quantity in use was investigated. We also analyzed leaching and of heavy metals in nanowaste. Chemical composition was determined using Xray diffraction and fluorescence (XRD and XRF) and transmission electron microscopy (TEM). Using XRF and XRD analysis, sludge from a facility using zinc oxide was found to have silicon dioxide (SiO₂) and TiO₂ as its main components. Sludge from a facility using TiO₂ was found to have TiO₂ as its main component. Samples of Ag nanoparticle and C nanotubes manufacturer measured elemental components of Ag and C, respectively. TEM analysis showed Si O₂ in the form of dust sample from a facility manufacturing ZnO. Carbon nanotube samples of manufacturers were in the form of fibers. Leaching test results showed low concentrations compared to the regulation criteria of the Wastes Control Act. Content result of Zn was detected at -111.7 ~ 24,843.4 mg/kg in ZnO samples. Content result of Ti was detected at 1.51 ~ 35.28 mg/kg in TiO₂ samples. Oil mop samples of Ag nanoparticle were detected in Ag (29,643.07 mg/kg) and Cu (15,600.8 mg/kg).

Key Words

WCNMs, Zinc oxide, Titanium dioxide, Silver nanoparticles, Carbon nanotube

모종근 Joung Gun Mo , 정한식 Han-shik Chung , 이광성 Kwang Sung Lee

DOI:10.9786/kswm.2017.34.6.555

Abstract

This paper is containing two study. The one is a land treatment of sewage sludge reduction through the indirect heating method and the other verifies conversion possibility of sludge organic matter to auxiliary fuel, steel thermal insulation material, byproduct fertilizer compost and find the suitable recycling method for J city. It was confirmed that about 88 percent of weight reduction for transportation efficiency and method verification. The analysis result of the carbonized product component showed the average low heating value of about 2,850 kcal and the moisture content of 1.4% which means the sludge is suitable as a fuel.

Key Words

Sewage sludge, Carbonization, Sludge

박훈채 Hoon Chae Park , 최항석 Hang Seok Choi

DOI:10.9786/kswm.2017.34.6.562

Abstract

The optimum design and scale-up of a fast pyrolysis reactor require a fundamental understanding of its hydrodynamics characteristics. Extensive investigations have been carried out, both theoretically and experimentally, to understand the hydrodynamic characteristics of gas-solid two-phase flow in a pyrolysis reactor, such as velocity field, solids concentration, and pressure drop. Numerical simulation can provide a promising alternative for studying the hydrodynamics of gas-solid flows in the fast pyrolysis reactor. In this study, computational particle fluid dynamics (CPFD) was used to investigate the hydrodynamic characteristics of bubbling fluidized bed (BFB) and conical spouted bed (CSB) reactors. These characteristics were analyzed in terms of pressure drop, solid distribution, and solid circulation rate. The BFB reactor was found to have a lower efficiency than the CSB reactor. The pressure drop of the CSB reactor was 25% less than that of the BFB reactor. The solid circulation rate of the CSB reactor was 68% greater than that of the BFB reactor.

Key Words

Bubbling fluidized bed, Conical spouted bed, CPFD, Multi-phase flow

연진모 Jin-mo Yeon , 정다위 David Chung , 엄남일 Namil Um , 정미정 Mi-jeong Jeong , 김기헌 Ki-heon Kim , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2017.34.6.571

Abstract

In this study, leaching and content tests of hazardous substances were analyzed to evaluate their recyclability to paper sludge and paperboard products. These findings were compared with standard controlled waste. In addition, the stability of these products was examined with respect to the recommended standards for heavy metal content in packaging materials. In the leaching test results, no regulated items were detected. Upon examining the stability of paperboard products, it was detected within the standard of most samples. Paper sludge usage accounts for only about 10% of paperboard raw materials. Therefore, harmful substances in paper sludge is not a problem, Leaching and content tests of harmful substances in the antifoaming agent used were investigated within the limits of all items. The pH of the paper sludge corrugated cardboard, and antifoaming agent was 7.49, 7.21, and 7.87, respectively. Therefore, these wastes did not account for the corrosiveness. In addition, there were no hazardous characteristics found for leaching, because all specified waste standards were satisfied.

Key Words

Paper sludge, Recyclability, Hazardous property, Antifoaming agent, Paper·cardboard

김종범 Jong-bum Kim , 장성호 Seong-ho Jang , 손현근 Hyun-keun Son , 류재용 Jae-yong Ryu

DOI:10.9786/kswm.2017.34.6.582

Abstract

Based on the results of the prior study, we conducted a study of the DRE (destruction and removal efficiency) and carbonization of xylene using high electron beam energies. The irradiation intensity of electron beam energy was 30 mA, and the irradiation times were 5.7, 11.4, 22.8, and 45.6 sec. The absorbed dose were 124.23, 248.46, 496.91, and 993.83 kGy. Xylene was completely removed at 248.46 kGy, and the main by-products were carbon particles. Carbon particle formation was increased with increased absorbed dos. The carbon particles were generated as fine particles with a size of 0.5 to 1.0 μm. The most common oby-products of these particle were carbon black and graphite.

Key Words

Volatile organic compounds, Xylene, Electron beam, Carbonization, By-product

이우진 Woo Jin Lee , Krishna Lal Chhetri , 현재혁 Jae-hyuk Hyun

DOI:10.9786/kswm.2017.34.6.589

Abstract

This study evaluated the heating value derived from waste trees generated by thinning in Daejeon Metropolitan City. These trees are generated and stored in the forest without being handled separately after thinning. They can be used as a source of energy as they have a high heating value and, to avoid landslides during heavy rain, must be taken away from the forests properly. In 2014, statistical data of waste trees in Daejeon showed there were 2,152,352 ㎥ of conifers, 924,836 ㎥ of broad-leaved trees, and 662,914 ㎥ of mixed forest. The moisture content of conifers was 15.8%, that of broad-leaved trees was 11.5%, and that of mixed forest was 13.7%. The ash content of conifers was 7.0%, that of broadleaved trees was 4.0%, and that of mixed forest was 11.4%. All three types of tree satisfy the moisture and ash content criteria for fluff type Bio-SRF, i.e., 25% and 15%, respectively. Therefore, they are deemed sufficiently valuable as a source of energy. The heavy metal (Hg, Cd, Pb, As, Cr) content of conifers, broad-leaved trees and mixed forests each satisfies the heavy metal content criteria for Bio-SRF, i.e., 0.6 mg/kg, 5.0 mg/kg, 100 mg/kg, 5.0 mg/kg, and 70 mg/kg, respectively. The lower heating value of conifers was 5,070 kcal/kg, that of broad-leaved trees was 4,660 kcal/kg, and that of mixed forest was 4,820 kcal/kg. All three types of tree satisfy the lower heating value criteria for Bio-SRF, which is 3,000 kcal/kg, and, therefore, are deemed sufficiently valuable as a source of energy.

Key Words

Thinning residue, Heating value, Thinning works, Bio-SRF

이희성 Hee-sung Lee , 조윤아 Yoon-a Cho , 황동건 Dong-gun Hwang , 김용준 Yong-jun Kim , 신선경 Sun-kyoung Shin , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2017.34.6.596

Abstract

In South Korea, as the price of natural minerals and lack of domestic resources increases, the import of waste into certain countries is gradually increasing. The largest portion of waste subject to a domestic import permit are lead-acid batteries. They account for more than 90% of the total import permits. In this study, the current status of waste leadacid batteries imported into Korea and their recycling status at domestic battery recycling sites were investigated. Waste generated from various lead-acid battery recycling plants were investigated for effective management of these batteries in South Korea. In addition, hazardous substances in the waste generated at recycling sites were analyzed to determine their environmental risk. Study sources were selected based on the industries registered on the Allbaro-system. For leaching analysis results, an arsenic content of 30.4 mg/L (1.63 to 109.13) was detected in slag, and 0.018 mg/L (N.D. to 0.018) of mercury was detected in wastewater treatment sludge. The contents of lead in slag and wastewater-treated sludge were measured as 85,599 mg/kg (52,476.4 to 150,466.8) and 41,722 mg/kg (18,082.6 to 68,958.1), respectively. In battery case scrap that was recycled by a second recycling company, lead was found to be 5.79 mg/L, exceeding the designated waste criteria of 3 mg/L. However, after the washing process, lead was no longer detected in the recycled product, P2. We conclude that it is necessary to keep the current secondary recycling process, with recycling after the cleaning process, in order to allow primary recycling companies to appropriately manage designated waste as it is discharged, collected, and transported.

Key Words

Lead-acid battery, Hazard of waste, Import/export of lead-acid batteries, Battery recycling process

권진홍 Jin Hong Kwon , 박기환 Gi Hwan Park , 김재용 Jae Yong Kim

DOI:10.9786/kswm.2017.34.6.608

Abstract

There are tens of millions of animal deaths annually due to infectious diseases such as AI (Avian Influenza) and foot-and-mouth disease. Currently, eco-friendly and economical methods of disposal of the resulting animal carcasses are being studied. Among them, the black soldier fly (Hermetia illucens, BSF) is attracting attention as an alternative to disposal methods that cause environmental pollution, such as incineration or landfills, because of its strong organic decomposition ability. In this study, the efficiency of BSF larvae for decomposition of broiler, pig, or duck was determined. Disposal ability relative to BSF larva level was measured for each. Our results confirmed that all three animals could be decomposed after 48 hours when BSF larva were injected at greater than 300% of the weight of the carcass.

Key Words

Black soldier fly (BSF), Carcass, Avian influenza, Foot-and-mouth disease, Stamping out

이승희 Seung-whee Rhee

DOI:10.9786/kswm.2017.34.6.614

Abstract

Moisture content is an important factor in landfill gas production and effective landfill stabilization management at bioreactor landfills. Moisture content was experimentally estimated by applying the rainfall hydrograph theory through cover materials, such as the general and bio-solid soil, in the Sudokwon landfill site. The rainfall hydrograph theory was used to analyze the water balance, in which moisture can be strongly affected by infiltration in the water balance. Cover material characteristics, such as bulk density, porosity, specific gravity, and hydraulic conductivity, were used to estimate the water balance of the landfill site. From the results of the water balance, runoff was increased, but evaporation and infiltration were decreased with increasing rainfall rate for both general and bio-solid soil. As the bulk density increased in both general and bio-solid soil, runoff was increased, but infiltration was decreased, because hydraulic conductivity in the cover material was decreased with increasing bulk density. Finally, the moisture content of landfill waste increased linearly, with increasing infiltration through the cover materials, even though the increment in moisture content was decreased along the depth of landfill.

Key Words

Bioreactor landfill, Rainfall hydrograph, Cover material, Hydraulic conductivity

신미수 Misoo Shin , 박민정 Minjeong Park , 김용주 Yongju Kim , 장동순 Dongsoon Jang

DOI:10.9786/kswm.2017.34.6.625

Abstract

Waste management has become a very crucial issue in many countries, due to the ever-increasing amount of waste material. Recent studies have focused on an innovative technology, gasification that has been demonstrated to be one of the most effective and environmentally friendly methods of solid waste treatment and energy utilization. In this study, a gasification process has been investigated systematically by numerical simulation, in order to obtain optimum design conditions for a commercial-scale facility of an updraft fixed-bed gasifier. Turbulent flow field was calculated with the incorporation of the proper flow model for turbulence and inertial resistance for the porous region of SRF loading. The calculated temperature and pressure drop (ΔP) at exit of the gasifier were in good agreement with measured values. Next, a detailed thermochemical model was employed to estimate the syngas composition by gasification. Results showed that a better plant solution depends on both the air-fuel ratio (AFR) and the steam and carbon mole ratio (S/C). In this study, the gasification efficiency was best at an AFR of 0.25-0.3 and an S/C below 0.5.

Key Words

Syngas, Gasification, Numerical simulation, Fixed bed gasification

이희성 Hee-sung Lee , 정미정 Mi-jeong Jeong , 조나현 Na-hyeon Cho , 조윤아 Yoon-a Cho , 김용준 Yong-jun Kim , 연진모 Jin-mo Yeon , 전태완 Tae-wan Jeon , 신선경 Sun-kyoung Shin , 정다위 David Chung

DOI:10.9786/kswm.2017.34.6.633

Abstract

In South Korea, the “Waste Control Act” regulates the use and purpose of recycling waste and specifies recycling methods and specific standards. However, these processes requires a long time and large budget, because they need to be reviewed based on data specific to the type of waste involved. The use and purpose of recycling can be considered by its functional and environmental aspects. The functional aspect of recycling may vary widely, depending on product characteristics In contrast, environmental standards will have more points in common. Recycling standards that consider the environmental impact and characteristics of waste are not prepared specifically. Therefore, when a large amount of waste is recycled, or recycling standards are applied to a new type of waste, the methodology for review of its environmental characteristics can be controversial. This study is meant to recognize the necessity of recycling standards and to prepare environmental standards and new recycling purposes for waste related to recycling three types of gypsum waste (phospho, titan, desulfurization). Several companies were selected for this study. In the gypsum waste-generating company, gypsum waste samples were collected and analyzed for pH, heavy metal content, water content, hazardous substance content, etc. In addition, we attempted to obtain the company's opinions on waste recycling. We determined the hazardous materials found in these three types of gypsum waste, raised awareness of waste, and confirmed that industry waste can be efficiently recycled for new uses under the improved.

Key Words

Heavy metal concentrations, Waste recycle, Titan gypsum, Phospho gypsum, Desulfurization gypsum

장성호 Seong-ho Jang , 양승빈 Seung-bin Yang , 정병길 Byung-gil Jung , 이원기 Won-ki Lee , S. Sivakumar , 정은상 Eun-sang Jung , 정태화 Tae-hwa Jung

DOI:10.9786/kswm.2017.34.6.642

Abstract

Soluble cutting fluids (SCFs) have been used in metal machining processes to improve the quality of metal processing equipment and products in modern society. Because the characteristics among metal machining processes differ, various types of cutting fluids are manufactured to enhance the cutting efficiency of different metals. Although SCFs are useful and essential materials, particular treatment is required attributable to the high concentration of nitrogen materials and chemical oxygen demand (COD). In this study, the removal efficiency of total nitrogen (T-N) contained in SCFs was analyzed using electrochemical treatment. The electrode was made of 316 stainless steel, which had been perforated to prevent an imbalanced sample concentration in the reactor. Cathodic and anodic electrodes were alternately inserted into an acrylic reactor. The removal efficiency of T-N in SCFs using 40 A/㎡, 60 A/㎡, and 80 A/㎡ current density, was 48.2%, 61.5% and 69.3%, respectively. The removal efficiency of T-N in SCFs with the addition of 0, 5 mM, and 10 mM NaCl was 69.3%, 74.6%, 77.6%, respectively.

Key Words

Electrochemical treatment, Soluble cutting fluids, T-N, Stainless electrode