전태완 Tae Wan Jeon , 박종은 Jong Eun Park , 강준구 Jun Gu Kang , 손준익 Jun Ik Son , 강영렬 Young Yeul Kang , 홍수연 Soo Youn Hong , 신선경 Sun Kyoung Shin

DOI:10.9786/kswm.2017.34.4.321

Abstract

Coal ash from power plants is divided into fly ash and bottom ash, which are produced after burning bituminous anthracite coal at 1,600℃. Coal ash is composed of fly ash (82%) and bottom ash (18%); while most fly ash is recycled as ready-mix concrete admixture and cement additive, bottom ash is left unused in landfill sites located within power plant grounds. This has been studied less comprehensively than fly ash; therefore, our aim was to assess the recyclability of the bottom ash generated by two (A & B) thermal power plants and thus identify the characteristics of hazardous substances in coal ash that are generated in power plants and evaluate the environmental contamination likelihood in the recycling of the produced coal ash. Currently, emitters such as thermal power plants have various requirements for the recycling of coal ash (bottom ash and they are also required by law to consider how the country’s environmental impact may be affected by recycling large amounts of coal ash. The concentrations of hazardous substances contained in coal ash (bottom ash) are generally lower than the criteria for soil contaminants and the standard for hazardous substances contained in designated waste. We found no significant leaching of heavy metal and its concentration; however, the levels of heavy metals in coal ash were generally low. The results of column leaching testing for potential environmental impact assessment indicated that increased leaching time might lead to the reduced ionic concentration of coal ash.

Key Words

Power plant, Coal ash, Column leaching test, Ecological toxicity

김형우 Hyeong-woo Kim , 박흥석 Hung-suck Park

DOI:10.9786/kswm.2017.34.4.330

Abstract

Industrial symbiosis (IS) activities within an industrial complex can enhance environmental and economic efficiencies. This study proposed a simplified life cycle assessment (LCA) methodology as an effective tool with which to evaluate the reduction of environmental impact of IS activities. In this method, the variation of resources and energy consumptions before and after IS activities are proposed to simply evaluate its lifecycle environmental impacts. The simplified LCA was applied to an IS case between an industrial waste incineration plant and a steam production plant of a paper mill firm in the metropolitan city Ulsan. The system boundary and inventory were set for this IS, and an environmental impact assessment was carried out by standard and proposed LCA methods. The results showed that the environmental impacts after IS decreased in all impact categories with regard to the consumption reduction of boiler fuel used at the paper mill. Furthermore, the performance of environmental improvement activities such as IS can be simply evaluated by only considering the input and output changes in the environmental improvement activities. In this IS case study, the environmental impact was decreased by 11.7% (weighted impact base). This was due to the utilization of waste heat generated from an incineration plant in the process of the paper mill firm.

Key Words

Direct and indirect impact, Environmental impact, Environmental improvement activities, Industrial symbiosis, Life cycle assessment

김주호 Joo-ho Kim , 심종호 Jong-ho Sim , 박중구 Jung-gu Park

DOI:10.9786/kswm.2017.34.4.341

Abstract

The growth of the Waste-to-Energy (WTE) industry is attracting attention as a powerful means of reducing greenhouse gas emissions; the Korean government is supporting various efforts such as increasing R&D investment. Despite the importance of the WTE industry, the analysis of R&D efficiency remains insufficient. This study analyzes the R&D efficiency of the Korean WTE industry and its determinants. After R&D activities are separated into input and output, R&D efficiency is analyzed with regard to whether R&D input contributes to increased R&D output using multiple regression and logistic regression methodologies based on the survey of Korean WTE firms. In the results of analysis, the introduction of new products and services was positively affected by R&D manpower and education-training. In addition, the redesign of products and processes was positively affected by R&D expenditure, R&D manpower, education-training, and the reward system. The policy implication is that education and training for R&D manpower should be provided to improve R&D efficiency, and there should be investment in basic and applied research and development research should be expanded to gain global competitiveness.

Key Words

Korea, Waste-to-Energy Industry, R&D, Efficiency

김교근 Kyeo-keun Kim

DOI:10.9786/kswm.2017.34.4.352

Abstract

The recyclability of waste generated in Korea was determined by sampling ten kinds of sludge to analyze its chemical composition and organic content. We also analyzed the regulatory items for waste control laws and soil environmental laws. Investigation of the leaching property revealed that all sludge samples were classified as general waste and the sludge samples were not types of waste that are prohibited or restricted from being recycled. The S1 sample was evaluated as organic sludge upon measuring the organic content and finding it to be 40% or higher; the other samples were deemed inorganic. Organic sludge S2 exceeded the Zn in the second regional standard of soil environmental laws. Among the inorganic sludge samples, S2 and S8 were considered most likely to be recycled because there were no hazardous substances that exceeded the standard. However, they should be recycled safely after the evaluation of their recyclability according to the recycling purpose and method. Especially the S5 sample was deemed difficult to recycle because it exceeded the third regional standard, which is the highest soil standard.

Key Words

Sludge, Heavy metal, Leaching property, Recyclability

박훈채 Hoon Chae Park , 이병규 Byeong Kyu Lee , 최항석 Hang Seok Choi

DOI:10.9786/kswm.2017.34.4.359

Abstract

This study aims to investigate the behavior characteristics of solid particles within conical spouted beds depending on the inlet gas velocity. Electrical capacitance volume tomography was applied to the measurements of the instantaneous gas-solid flow structures in a conical spouted bed. The effects of inlet gas velocity on the solid volume fraction and pressure were investigated. The different inlet gas velocities showed a certain influence on the gas?solid flow behaviors in the conical spouted bed. A symmetric core-annulus structure in the conical spouted bed was observed. Solid particles in the core and annulus areas were mixed at the ratio U/Ums = 1.6. It would be efficient to operate a fast pyrolysis reactor for the high heat and mass transfer of waste woods and sand particles.

Key Words

Conical spouted bed, Fast pyrolysis, ECVT, Multi-phase flow

장정원 Jeong-won Jang , 김연희 Yun-hee Kim , 이윤국 Youn-goog Lee , 조민철 Min-cheol Cho , 정희윤 Hee-yoon Jeong , 조영관 Young-gwan Cho , 김은선 Eun-sun Kim , 김동수 Dong-soo Kim

DOI:10.9786/kswm.2017.34.4.369

Abstract

The concerns about potential risks and hazards in children’s playgrounds are increasing and the restrictions for environmental harmful substances in playgrounds have been reinforced in many countries. In this study, the concentrations of heavy metals were analyzed in 142 samples including 105 of sand flooring and 37 playing equipment such as swing, slide, sporting equipment, bench and fence in 18 children’s playgrounds. Heavy metals in sand flooring were investigated and categorized by natural environmental factors such as season, rainfall, post-rainy day, and artificial factors as road, type, and material of nearby play equipment. The concentration of heavy metals such as Pb, Hg, Cu, and Zn were significantly higher in sand flooring near the play equipment than at places away from the playing equipment (p < 0.05). Spearman’s rank correlation analysis showed that play equipment had a positive correlation with the sand flooring with regard to the concentration of Pb (r = 0.42, p < 0.01) and Cu (r = 0.39, p < 0.01). The concentration of heavy metals in the sand flooring showed a statistically significant difference depending on the season, post-rainy day, the distance from a roadway, type of equipment, and the material. The play equipment’s heavy metal concentration and other environmental factors contributed to the heavy metal concentration in the sand flooring’s surface in playgrounds.

Key Words

Heavy metal, Children’s playground, Playing equipment, Sand flooring, Environmental factor

송연민 Yun-min Song

DOI:10.9786/kswm.2017.34.4.378

Abstract

The aim of this study is to measure the exact average specific cake resistance in cake filtration. Using the new experimental method “filtration-permeation,” the average specific resistances were measured for various conditions as follows. First, the experiment with changing pre-sedimentation time and the filtration of sediment were conducted to determine the influence of sedimentation on the average specific resistance. There was a wide difference between the values of α_av with various sedimentation times. Regarding the variation in the pre-sedimentation time, there was maximum 2.9x difference between the measured values of the average specific resistances for the filtration of calcium carbonate suspension. The “filtration-permeation” of bentonite floc and that of biological flow were also performed to establish a method for obtaining the average specific resistance of flocs.

Key Words

Filtration-permeation, Average specific resistances, Pre-sedimentation time

정벼리 Byeo Ri Jeong , 전영남 Young Nam Chun

DOI:10.9786/kswm.2017.34.4.386

Abstract

Methane (CH₄) and carbon dioxide (CO₂) are the components of gas produced by biomass pyrolysis gasification and biogas from bioreactor. These two gases are known as the main greenhouse gases that affect world climate change. This study has tried to investigate the characteristics of microwave heating reformation that seeks to convert the produced gas into valuable fuel energy. Through microwave reforming, a carbon receptor was used as two types of sludge char and commercial activated carbon. Regarding CH₄ reformation, H2 was produced via thermal decomposition with generated carbon (C) that adsorbs on the active catalytic plate and reduces the active catalytic reaction. In the case of CO₂ reformation, CO was produced via reaction with the carbon on the surface of the carbon receptor; this can solve the problem of removing the adsorbed carbon from the carbon receptor. Using the sludge char as the carbon receptor showed higher gas yields for H₂ and CO than the commercial activated carbon receptor, while giving a comparatively higher heating value for the sludge char receptor. In addition, in the cases of lower temperature and residence time in the carbon captor, the CH₄ and CO₂ conversions and the reforming gas yields had lower values.

Key Words

Microwave heating, Pyrolysis gasification, Gas reforming, Greenhouse gas, Carbon receptor

권은진 Eun-jin Kwon , 길태형 Tae-hyung Kil , 우제민 Je-min Woo , 유영국 Young-kuk Yu , 박영성 Yeong-seong Park

DOI:10.9786/kswm.2017.34.4.395

Abstract

Biomass adsorbents were prepared from fallen oak leaves. In the activation process for fallen oak leaves, various operating parameters such as the activation temperature (600-900℃), steam injection rate (5-15 cc/hr), and steam injection time (1-3 hr) were adopted. For analyses of the manufactured adsorbent, various methods such as scanning electron microscope (SEM), measurements of the BET surface area and chemical composition analyses were adopted. Regarding major adsorption characteristics, the adsorption equilibrium capacity was measured using batch type experimental apparatus for various biomass adsorbents. The experimental result showed that the H2S adsorption equilibrium capacity of the adsorbent made from fallen oak leaves decreased as the activation temperature and steam injection rate increased for a given range.

Key Words

Biomass adsorbent, Oak fallen leaves, H₂S, Adsorption equilibrium capacity

권은혜 Eun-hye Kwon , 손준익 Jun-ik Son , 권영현 Young Hyun Kwon , 김기헌 Ki-heon Kim , 윤영삼 Young-sam Youn , 이수영 Su-young Lee , 전태완 Tea-wan Jeon , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2017.34.4.402

Abstract

Domestic industrial waste small-scale industrial incinerators produce less than 200 kg/hr; this study chose 13 of the 249 potential facilities. The target average emissions for air pollutants resulting from the facilities were SOx 13.56 ppm, NOx 82.74 ppm, NH₃ 19.95 ppm, HCl 54.33 ppm, HF 0.84 ppm, Hg N.D, As 0.1 ppm, H₂S N.D. Dust and heavy metal analysis results for the facilities revealed Dust 32.51 mg/S㎥, Cd 0.04 mg/S㎥, Pb 0.20 mg/S㎥, Cr 0.08 mg/S㎥, and Cu 0.03 mg/S㎥. Combustion indicators were O₂ 11.58% and CO 271.20 ppm. Average PCDDs/DFs were 17.87 ng ITEQ/ton. The target facilities were equipped with anti-pollution facilities. However, some items were found to exceed the emission standards. These results are even equipped with control facilities due to manual limitation actions of the management personnel. Therefore, it is determined that the emission control of contaminants is difficult.

Key Words

Incinerator, Small-scale incinerators, Air pollutant emission, Industrial waste small-scale incinerators

조윤아 Yoon-a Cho , 이희성 Hee-sung Lee , 엄남일 Nam-il Um , 김용준 Yong-jun Kim , 신선경 Sun-kyoung Shin , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2017.34.4.410

Abstract

Waste lead-acid batteries are recycled and turned into lead and plastics (polypropylene and ABS etc.) through collection, disassembly, crushing, sorting, and washing. In particular, lead is recovered from the scrap by recycling companies and used as raw material in a smelter. Refined lead from smelters is reused as a raw material in new products. It is highly valuable to recover effective metals from waste lead-acid batteries that contain a significant amount of lead under environmentally sound management. In this study, we investigated the composition change and its cause in the process of use and phased out products to understand the discharge characteristics of waste lead-acid batteries. We also suggest examining the correlation between the waste lead-acid battery and the recovered lead to estimate the potential amount of recoverable lead. Finally, we produced a strategic method for accelerating national resource circulation by comprehending the flow of resources and their residues from wastes and propose it as a policy in baseline data.

Key Words

Waste lead-acid battery, Lead sulfate, Charge, Discharge

박휘언 Hwieon Park , 최종현 Jonghyun Choi , 장용철 Yong-chul Jang

DOI:10.9786/kswm.2017.34.4.418

Abstract

Brominated flame retardants (BFRs) including PBDEs, TBBPA, and HBCD have been used in a variety of products such as automobiles, electronic products, building materials, and textiles. Because some of BFRs are known to be toxic, persistent, bioaccumulative in the environment, they have a great potential and possibility of human exposure and the environmental release through the use, treatment and disposal of products containing BFRs. Although there have been various efforts on laws and regulations of the restriction on the use of BFRs in many countries, only limited information regarding the levels, flow, treatment technology and regulations of products and wastes containing BFRs is available. In this study, the levels, current regulations and treatment guideline on products and wastes containing BFRs in electronics, automotives, construction materials, and textiles have been examined and summarized. Relative high levels of BFRs in TVs, construction materials and end-of-life vehicles were found, while textiles contained less amounts of BFRs. According to the study, more strengthened regulations are currently underway around the world. Thus, more limited use of BFRs such as deca-BDE in products and wastes is expected. Other chemicals such as TBBPA and HBCD are being evaluated for toxicity and risk assessment. Specific regulatory guideline of BFRs containing products after use (e.g. collection, separation, treatment) should be developed to prevent the widespread dispersion in the environment and human exposure of such chemicals as a result of improper disposal such as incineration and landfilling.

Key Words

BFRs, PBDEs, Waste, Recycling, Environmental regulation, Hazard assessment