김진관 Jin Gwan Kim , 오민아 Minah Oh , 이명호 Myungho Lee , 이재영 Jai-young Lee

DOI:10.9786/kswm.2017.34.5.442

Abstract

A series of laboratory tests were carried out to verify the strength characteristics of soil-cement improved by the biomineralization of microorganisms and to evaluate the utilizations of soil-cement mixed with oyster shell as an alternative aggregate. The higher the mixed oyster shell ratio, the lower the specific gravity and dry density. The mixing processes were more likely to change the liquid limit and plasticity index of the soil-cement into those for sand. The uniaxial compressive strength of soil-cement mixed with 20% oyster shell and 1 × 10³ cells/mL of microorganisms satisfied the requirements of 3,000 kPa for seven days of curing in the Standard Specification for Public Works.

Key Words

Soil-cement, Oyster shell, Biomineralization, Microorganisms

박선오 Seon-oh Park , 강영렬 Young-yeul Kang , 황동건 Dong-gun Hwang , 김용준 Yong-jun Kim , 유혜영 Hye-young Ryu , 홍수연 Su-yeon Hong , 전태완 Tae-wan Jeon , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2017.34.5.449

Abstract

In this study, we analyzed the content of five hazardous heavy metals (Pb, As, Hg, Cd, and Cu) in cement products distributed in Korea over the last five years. The types and amounts of waste inputted into a cement kiln or added as alternative fuels and secondary raw materials were investigated, and the correlation between heavy metal content and input waste were analyzed. The measured heavy metal content in cement products were 26.9-95.0 mg/kg for lead, 6.08-19.15 mg/kg for arsenic, 0.0339-0.2617 mg/kg for mercury, 2.937-4.392 mg/kg for cadmium, and 22.25-267.42 mg/kg for copper. In addition, based on correlation analysis results between the heavy metal content of cement products and added input wastes, major wastes that affected the heavy metal content among the 11 types of waste were iron, coal ash, waste tires, waste plaster, desulfurization gypsum, and waste synthetic resin.

Key Words

Cement products, Heavy metal content, Secondary raw material, Alternative fuel

김기헌 Ki-heon Kim , 권영현 Young-hyun Kwon , 윤영삼 Young-sam Yoon , 오정근 Jung-keun Oh , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2017.34.5.458

Abstract

The use of electrical and electronic products made of low specific gravity and easy processing plastics has increased alongside industrial development. As these products were abandoned, environmental problems such as Dioxine and Furan began to rise. Accordingly, through long-time reviews and discussions, the EU has implemented the Restriction of Hazardous Substances (RoHS) and the Waste Electrical and Electronic Equipment (WEEE) regulations. In addition, the Stockholm Convention was adopted in April 2011 to regulate wastes containing brominated flame retardants. Therefore, the Basel Convention issued technical guidelines and environmentally friendly treatments for wastes containing brominated flame retardants. Proper management and treatment plans that are suitable to Korea’s circumstances are required for Korea to respond to both conventions and changing trends in international POPs management. In this regard, the study identified domestic and international trends in environmental regulations and usages, obtained fundamental data for the management of waste containing brominated flame retardants, and investigated the current status of waste generation in Korea. The results of analyses were used to make a lab-scale incineration reactor as the basis for setting incineration temperature ranges for experiments. After incineration, five general air pollutants (O₂, CO, CO₂, SOx, and NOx) and three components of BRFs in emission gases and flooring were analyzed to identify whether the PBDEs in waste can be destroyed in a stable and environmental manner during heat treatment. In the analysis, HRMS was used for PBDEs and GC/MS/MS for TBBPA and HBCD. PBDD/DFs was proportionally increased in facilities that had high concentrations of PCDD/DFs during incineration. In conclusion, wastes containing brominated flame retardants in Korea can be incinerated in an environmentally friendly manner.

Key Words

BFRs, Incineration, PBDD/DFs, Persistent organic pollutants

류승형 Seung Hyeong Ryu , 서영주 Youngjoo Seo , 박준우 Joonwoo Park , 김신동 Shin Dong Kim , 박성순 Seong Soon Park

DOI:10.9786/kswm.2017.34.5.468

Abstract

This study was carried out to examine the characteristics of hydrogen sulfide adsorption using an iron hydroxide-based adsorbent. The prepared adsorbent was discussed with regard to its adsorption capacity and analyzed via surface analysis methods to illustrate the physical characteristics of hydrogen sulfide adsorption. As the drying temperature increased, the adsorption capacity of the adsorbent decreased from 29.15wt% to 22.73wt%. The adsorption capacity was decreased as the space velocity increased and showed an adsorption capacity of about 3.65 at 3,157.6 h^-1. The effect of sulfur dioxide was to decrease the adsorption capacity from 29.15wt% to 27.94wt%. The adsorbent exhibited the amorphous type in its physical appearance based on XRD and EDS analysis.

Key Words

Iron oxide, Iron hydroxide, Hydrogen sulfide, Adsorption

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

DOI:10.9786/kswm.2017.34.5.474

Abstract

This study was conducted to investigate the effects of inoculum and carbon sources on anaerobic digestion characteristics. The treatments were combinations of inoculum (digestate of cattle manure and rumen fluid) with carbon sources (starch, cellulose, and xylan). Anaerobic digestion was performed in triplicate at 37℃ for 18 days at 100 rpm. Sampling was performed at 0, 1, 2, 3, 4, 5, 7, 9, 12, 15, and 18 days to measure pH, ammonia-N, volatile solids reduction, the cumulative methane content, and the cumulative methane production. There was a significant difference in methane content depending on the carbon source and there was a significant difference in pH, ammonia-N, methane production, and methane content depending on the inoculum (P < 0.05). The results of methane production were higher in the digestate of cattle manure treatment than in the rumen fluid treatment (P < 0.05). In this study, different digestive patterns depending on the type of carbon source could be used as basic research data to set the hydraulic residence time of anaerobic digestion facilities. In addition, the use of ruminal fluid as an inoculum may help accelerate the hydrolysis and acid production steps.

Key Words

Inoculum, Carbon source, Anaerobic digestion, Biomethane potential

이도연 Doyeon Lee , 김하나 Hana Kim , 박재혁 Jae Hyeok Park , 배달희 Dal-hee Bae , 이승용 Seung-yong Lee , 박재현 Jaehyeon Park , 선도원 Dowon Shun

DOI:10.9786/kswm.2017.34.5.482

Abstract

There increasing demand for technologies that are capable of producing heat and electric energy by burning fuels such as solid refuse fuel (SRF) and biomass to mitigate the effects of greenhouse gas emissions from fossil fuels and global warming in the field of thermal power generation. In particular, conversion of SRF into energy (Waste to Energy) is the promising technology with high economic and social benefits. The high temperature corrosion of the heat exchange tube is the most important factor that affects the economic deterioration of a circulating fluidized bed boiler using solid refuse fuel, due to operating time decrease and the periodic shutdown during plant operation. The purpose of this study was to examine the high temperature corrosion characteristics of boiler superheater tubes. The change of corrosion characteristics according to the temperature and alkali chloride salt can be investigated by analyzing the morphology of the surface and the microstructure of specimen cross-section and examining the changes in the physical and chemical properties. The degree of corrosion increased as the temperature increased and the weight of the alkali chloride specimen deposit decreased due to the volatilization of the metal chloride compound above 700℃. Deposits of KCl were found to accelerate corrosion by destroying the oxide layer and forming potassium compounds.

Key Words

Waste to energy, High temperature corrosion, Alkali chloride, Superheater, Boiler tube

유장연 Jangyeon Yoo , 알핀이마누엘 Emmanuel S. Aalfin , 김억조 Eok-jo Kim , 장재수 Jae-soo Chang , 고성철 Sung-cheol Koh

DOI:10.9786/kswm.2017.34.5.490

Abstract

Spent coffee grounds, activated sludge, chicken manure, and agricultural waste-derived biochar were used to manufacture eco-friendly and functional compost via the bioaugmentation of white rot fungus and plant growth that promotes beneficial microorganisms. Six lab-scale composting reactors were established to perform composting. After composting was completed over 45 days, the composts were analyzed for major elements, physico-chemical characteristics, compost maturity, and compost effectiveness on crop growth and quality. Concentrations of T-N and PO₄^3- significantly increased in the composts that had been amended with biochar and/or white rot fungus compared to the control, while those of NO₃^--N, TOC and TOC/T-N had significantly decreased, indicating the occurrence of effective composting. Besides, the germination indices of these composts were also generally higher than the control by 10-34%, indicating that the composts were mature. The four composts amended with biochar and/or white rot fungus (TR-3, TR-4, TR-5, TR-6) also appeared to stimulate more growth in lettuce compared to commercial organic fertilizers (by 36-104%). Besides, composts TR-3 and TR-4 respectively enhanced DPPH scavenging activity in lettuce leaves by 58% and 49%, while TR-4 and TR-5 respectively enhanced the total phenolic content (TPC) by 44% and 37%. This implies that the amendment of biochar and the bioaugmentation of white rot fungus could facilitate the composting process for the production of quality functional compost that is able to enhance the antioxidant content in crops. Quality composts could better compete with the commercially available fertilizers in the market, leading to the eco-friendly recycling of organic wastes such as spent coffee grounds, sludge, chicken manure, and agricultural waste.

Key Words

Composting, Spent coffee ground, Biochar, White rot fungus, Antioxidants

허준오 Jun-oh Heo , 조정규 Jung-kyu Jo , 박인욱 In-wook Park , 형원길 Won-gil Hyung

DOI:10.9786/kswm.2017.34.5.500

Abstract

Even though cement a major foundational ingredient in modern architecture, it is known to destroy the environment due to its high energy consumption and how its production releases large amounts of carbon dioxide. To address this situation, the cement industry has proceeded to study how to reduce the amount of CO₂ released and has recently started developing unused non-sintered cement. Inaddition, studies are in active development for cement that has not gone through the burning process. If it is possible to make cement using blast furnace slag and industry outgrowth without the use of clinker, it can be expected to help when running out of limestone and to mitigate the pollution problem through CO₂ emissions. This study apprehended the measurement of kinematical characteristics through measuring polymer nonsintered cement flexural and compressive strength and analyzing the pH · Cl- Penetration Depth characteristic, through the SEM test also analyzes the reaction of the hydration mechanism, the result of decrementing the water/cement ratio, and entrained air contents from the mixing of polymer, and conducts that durability test for the absorption rate and carbonation experiments. The results of experimentation show excellent chemical and mechanical properties compared to ordinary Portland cement.

Key Words

Non-sintered cement, Polymer dispersion, Eco-friendly cement, Durability

용상운 Sang-woon Yong , 이우진 Woo-jin Lee , 양한솔 Han-sol Yang , 현재혁 Jae-hyuk Hyun

DOI:10.9786/kswm.2017.34.5.509

Abstract

This study performed a basic test to evaluate the energy value of food waste and ground coffee residue, and measured the calorific value of mixtures of food waste and ground coffee in the mass ratios of 1 : 1, 1 : 2, and 2 : 1. According to the results of this study, food waste, ground coffee, and their mixtures are technically viable as energy resources because they all meet Korea’s quality criteria for Bio-SRF. The proximate analysis results for food waste and ground coffee mixture showed 51.6% moisture, 46.2% combustibles, and 2.2% ash content. The high calorific value and low calorific value measured by the SE-C5500 Bomb Calorimeter were 4,602 kcal/kg and 3,927 kcal/kg, respectively. Heavy metal analysis showed the absence of mercury (Hg) and arsenic (As). Therefore, food waste, ground coffee residue, and their mixture sample met Korea’s quality criteria for Bio-SRF, which are technically and economically viable for use as bio-solid fuel (Bio-SRF).

Key Words

Food waste, Ground coffee residue, Calorific value

이유리 Yu Ri Lee , 박훈채 Hoon Chae Park , 최명규 Myung Kyu Choi , 최항석 Hang Seok Choi

DOI:10.9786/kswm.2017.34.5.518

Abstract

The development of renewable energy is currently strongly required to address environmental problems such as global warming. In particular, biomass is highlighted due to its advantages. When using biomass as an energy source, the conversion process is essential. Fast pyrolysis, which is a thermochemical conversion method, is a known method of producing bio-oil. Therefore, various studies were conducted with fast pyrolysis. Most studies were conducted under a lab-scale process. Hence, scaling up is required for commercialization. However, it is difficult to find studies that address the process analysis, even though this is essential for developing a scaled-up plant. Hence, the present study carries out the process analysis of biomass pyrolysis. The fast pyrolysis system includes a biomass feeder, fast pyrolyzer, cyclone, condenser, and electrostatic precipitator (ESP). A two-stage, semi-global reaction mechanism was applied to simulate the fast pyrolysis reaction and a circulating fluidized bed reactor was selected as the fast pyrolyzer. All the equipment in the process was modeled based on heat and mass balance equations. In this study, process analysis was conducted with various reaction temperatures and residence times. The two-stage, semi-global reaction mechanism for circulating fluidized-bed reactor can be applied to simulate a scaled-up plant.

Key Words

Biomass, Circulating fluidized bed reactor, Fast pyrolysis, Process analysis

나해리 Haeri Na , 이현수 Hyun-soo Lee , 이지연 Chi-youn Lee

DOI:10.9786/kswm.2017.34.5.528

Abstract

Coal briquette ash is an inorganic and non-combustible material. Although coal briquette ash is mainly composed of SiO₂, Al₂O₃, and is an acceptable raw industrial material (containing Fe₂O₃, K₂O, MgO, CaO, TiO₂, and Na₂O), it is merely considered waste and is exploited as a building material for concrete admixtures and bricks. Because mullite (3Al₂O₃ 2SiO₂), which coal briquette ash contains, is a stable compound with a crystalline structure, it plays essential roles in its fracture strength and bending strength. This study serves the purpose of developing environmentally friendly, economical clay bodies through the use of coal briquette ash as a substitute for kaolin to provide Al₂O₃ and SiO₂. We also investigated the seed effects during sintering process by feeding mullite directly into clay bodies. The results show that in 1,300℃ heat, a mixture of 40% coal briquette ash, 40% feldspar/limestone (8 : 2), and 20% clay indicates a fracture strength value of 525 kgf/㎠, an absorption rate of 0.72%, burning shrinkage of 11.5%, and an average bending strength of 0.6 cm, which is superior to other clay bodies. The addition of coral briquette ash in clay bodies promoted mullite formation and grew as mullite acted as a seed. In addition to the developing clay bodies, it can also make an oatmeal-colored glaze to widen the spectrum of its usability. This study will help resolve waste problems, reduce environmental pollution, and raise economic value by using coal briquette ash as a raw material for ceramics. Clay bodies made with coal briquette ash are expected to continuously contribute to the development of the ceramics industry with upcycling effects.

Key Words

Coal briquette ash, Recycling clay, Mullite, Mullite seed, Ceramic oatmeal

박상우 Sang-woo Park

DOI:10.9786/kswm.2017.34.5.431

Abstract

The accessibility and accuracy of the data for the advancement of national waste statistics in South Korea were examined in this study and then compared to those of the European Union, the United States, and Japan. Accessibility and accuracy were each examined by three indices, which revealed that accessibility was generally lacking, except that Korea processed and provided a key summary. Regarding accuracy, the recycling calculation method, about which some concerns have recently been raised, was reviewed in this study; it was found that the tallying of recycled waste volume in South Korea has not been carried out scientifically. This result indicates that the data that should be used in the future to determine whether resource recycling objectives have been met and to calculate the greenhouse gas inventory are inaccurate. Furthermore, the differences between countries in the standards used to determine the amount of incinerated waste and energy recycling in completing the greenhouse gas inventory were verified in this study. Complying with ever-changing waste policies requires establishing measures for advancing the accessibility and accuracy of national waste statistics.

Key Words

Waste statistics, Accuracy, Municipal waste, Accessibility