박재영 Jae Young Park , 김준범 Jun Beum Kim , 황용우 Young Woo Hwang , 이익모 Ik Mo Lee , 천영우 Young-woo Chun

DOI:10.9786/kswm.2016.33.8.721

Abstract

The objective of the current study was to analyze the current safety status of formaldehyde. More than 670 manufacturers in 15 business sectors were enrolled. A MFA of the manufacturers showed that manufacturer M, which specializes in the manufacture of basic organic chemicals, used the most formaldehyde (120,000 tons), and manufacturer B, which specializes in the manufacture of general varnish and related products, used the least (8 tons). The results of this study can be used to collect scattered material flow and identify different parts of the country where a nationally produced substance, such as formaldehyde, can be stored. The details of the toxicity reflected in the composition and the amount of formaldehyde are likely to be utilized to produce personal protective equipment.

Key Words

Material flow analysis, Formaldehyde, Chemical flow analysis

김우일 Woo-il Kim , 조나현 Na-hyeon Cho , 최효현 Hyo-hyun Choi

DOI:10.9786/kswm.2016.33.8.731

Abstract

Nanomaterials affect human and environmental health through applications, such as waste-containing nanomaterials (WCNMs) generation, product use, treatment and disposal. As the number of applications increases, more and more nanomaterial waste will be generated. The increased use of nanomaterials introduces nanoparticles intentionally or unintentionally into waste streams. This study examined WCNMs in a domestic industrial area and selected silicon dioxide as an objective nanomaterial because it is ranked first in circulation and quantity of use. We analyzed leaching and concentration of heavy metals in nano-waste. Chemical composition was determined using X-ray powder diffraction (XRD) and X-ray fluorescence (XRF), and the unique properties of nano-waste were examined using particle size distribution analyzer and transmission electron microscopy (TEM). The results of the leaching test showed lower or undetectable concentrations than those of standard hazardous substances in Korea. However, some samples had higher concentrations than criteria of hazardous chemicals in contaminated soil. The XRF results revealed that silicon dioxide was the major component with a known particle size < 100 nm in liquid waste samples.

Key Words

WCNMs, Silicon dioxide, Leaching test, Content concentration

김영진 Young-chin Kim

DOI:10.9786/kswm.2016.33.8.743

Abstract

The indoor thermal conductivity test, unfrozen water test, and freezing pressure test were conducted on soil mixed with waste vinyl aggregate (PE aggregate). Consequently, lower thermal conductivity, less unfrozen water, and lower freezing pressure resulted from higher PE aggregate mixing ratios. Furthermore, the plate loading test and frost penetration depth test were conducted on field model road with a sub-base of PE aggregate and crushed stone. As a result, the bearing capacity of the road mixed with 10% PE aggregate exceeded the requirement, whereas frost penetration depth was reduced by 39% compared to that of using crushed stone only.

Key Words

PE aggregate, Thermal conductivity, Unfrozen water, Freezing pressure, Frost penetration depth

권오철 Oh Chul Kwon , 박영규 Young Gyu Park

DOI:10.9786/kswm.2016.33.8.749

Abstract

Biogas has been used to remove water content and hydrogen sulfide (H₂S). Removing water requires a low temperature process; thus, our study investigated removing H₂S under high pressure and low temperature. Several experiments were conducted to investigate removal of H₂S from a biogas stream by optimizing chemical absorption and the chemical reaction with a Fe/EDTA solution. The roles of Fe/EDTA were studied to enhance removal efficiency of H₂S due to oxidization by Fe⁺³/EDTA. The objective of this study was to explore the feasibility of enhancing toxic gas treatment in a biogas facility. A biogas purification strategy affords many advantages. For example, the process can be performed under mild environmental conditions and at low temperature, and it removes H2S selectively. As the Fe-EDTA concentration increased, the H₂S conversion rate increased because the Fe-EDTA complex was highly stable. The optimal pH to stabilize the chemical complex during oxidation of H₂S was 9.0.

Key Words

Hydrogen sulfide, Ferric chelate, Biogas, High pressure, Low temperature

이경호 Kyeong Ho Lee , 심명화 Myung Hwa Shim , 유경선 Kyung Seun Yoo

DOI:10.9786/kswm.2016.33.8.760

Abstract

Sulfate produced during anaerobic reduction limits the activity of methanogens but it is not reflected in the Intergovernmental Panel on Climate Change (IPCC) methodology for estimating CH₄ emissions. In this study, CH₄ emissions from the Sudokwon landfill site were estimated by adopting a methane correction factor, which was determined through the relationship between the COD/sulfate ratio and CH₄ generation. Although the gas originating from the Sudokwon landfill site has not produced any environmental problems in recent years due to gas collection and soil cover maintenance activities, CH₄ emissions estimated by the IPCC methodology indicated that only 60% of the CH₄ was recovered and the remainder was emitted into the atmosphere, suggesting a potential environmental problem. Accordingly, CH₄ estimates determined according to IPCC methodology must be modified by adopting the methane correction factor and considering the effect of sulfate concentration.

Key Words

IPCC methodology, CH₄ emission, COD/Sulfate

김다빈 Dabin Kim , 김현우 Hyun-woo Kim

DOI:10.9786/kswm.2016.33.8.772

Abstract

Biochemical methane potential (BMP) of residual wastes from transesterification was tested to safely recycle carcass via rendering process. The carcass was obtained from a buried site for avian influenza (AI) infected poultry. Rendered lipid generated by a pilot-scale high-pressure rendering process was the main source of transesterification for biodiesel recovery. To test the feasibility of waste-to-energy approach for AI infected carcass, we compared the BMPs of various fractions of rendered materials from the carcass. BMP and specific methanogenic activity results indicate that transesterification waste shows better digestibility than that of rendered lipid, and the digestion performance was comparable to that of liquid residue. Biogas yields of glycerol, rendered lipids, and liquid residue were estimated as 0.11 L/ g chemical oxygen demand (COD), 0.06 L/g COD, and 0.17 L/g COD, respectively. Regression analysis support that biogas production rate of glycerol (21 mL/g COD/d) was much faster than that of lipid (7 mL/g COD/d) while that of liquid residue was similar (24 mL/g COD/d). In summary using transesterification waste as a bioresource for bioenergy conversion can be a viable and sustainable option for the complete termination of burial site.

Key Words

Methane potential, Poultry lipid, Transesterification waste, Glycerol

정재현 Jae-hyun Jung , 추용식 Yong-sik Chu

DOI:10.9786/kswm.2016.33.8.778

Abstract

The quantities of low-grade reject fly ash (RFA) and paper sludge ash (PSA) generated are increasing annually and causing a serious social problem. In this study, the utility of these by-products was analyzed by using RFA and PSA as mineral admixtures. RFA-PSA blended mortar was fabricated and evaluated for use as a cement additive. RFA was milled to improve workability and the hydration reaction, and PSA was mixed with anhydrite to create the ettringite. As the RFA-PSA blended powder replaced 10% of the cement by weight, compressive strength of the mortar exceeded that of ordinary mortar prepared with Portland cement (OPC). Length change (28 days) of the RFA-PSA mortar with a 10% replacement rate was 68% of the OPC mortar and was 62% with a 30% replacement rate.

Key Words

Fly ash, Paper sludge ash, Mortar, Waste recycling

한소영 Soyoung Han , 최연석 Yeon-seok Choi , 최상규 Sang-kyu Choi , 김석준 Seok-joon Kim , 정연우 Yeon-woo Jeong

DOI:10.9786/kswm.2016.33.8.786

Abstract

Converting biomass to biocrude oil has been extensively studied worldwide as a renewable energy technology and a solution to global warming caused by overuse of fossil fuels because it is a carbon neutral fuel that originates from biomass and, thus, could help prevent climate change. Fast pyrolysis is an effective technology for producing biocrude-oil, and woody biomass is usually used as feedstock. Although many studies have been performed with this feedstock, high production cost and low higher heating value (HHV) have frequently reported as challenging barriers to commercialization. Thus, coffee ground residue was selected as an alternative feedstock to overcome this barrier due to its higher HHV than other biomasses, as well as an expected improvement in the recycling rate of organic waste from many coffee shops. A kinetic study on the thermal decomposition reaction of ground coffee residue was carried out previously to investigate pyrolysis characteristics by thermogravimetric analysis, and its kinetic parameters were studied using two calculation models. A bubbling-fluidized-bed reactor was used for fast pyrolysis and the yield and characteristics of the biocrude-oil from ground coffee residue were investigated at reaction temperatures of 400-600℃. The activation energy of the decomposition reaction was calculated separately to be 41.57 kJ/mol and 44.01-350.20 kJ/mol with the above two methods. The highest biocrude-oil content was about 51.7wt% at 550℃.

Key Words

Biocrude-oil, Coffee ground residue, Fast pyrolysis, Activation energy

신현욱 Hyeon Uk Shin , 송훈 Hun Song , 박기봉 Ki Bong Park

DOI:10.9786/kswm.2016.33.8.796

Abstract

Insulation materials used for building save energy and can be classified into inorganic and organic materials. Organic insulation emits toxic gases in a fire annd has lower water resistance. Inorganic insulation is heavy and has poorer thermal performance than that of organic material. This study evaluated the physical properties and fire resistance of lightweight inorganic insulation foaming material made of waste glass powder. The test results showed that the inorganic material performed well with low density and low thermal conductivity for an insulation material. Foam insulation material manufactured from glass powder was sufficient as a fire-resistant product.

Key Words

Fly ash, Waste glass powder, Foam material, Density, Thermal conductivity

김고은 Go-eun Kim , 장성호 Seong-ho Jang , S. Sivakumar , 송영채 Young-chae Song , 이원기 Won- Ki Lee , 정병길 Byung-gil Jung , 류재용 Jae-yong Ryu

DOI:10.9786/kswm.2016.33.8.804

Abstract

As industry continues to develop, the contents of various recalcitrant substances that are not removed by conventional wastewater treatment have increased in modern society. The metal working fluids (MWFs) used in the metal working process contain chemical substances, such as mineral oils, anticorrosive agents, extreme-pressure additives, and stabilizers, as well as high concentrations of organics and ammonia-nitrogen. Accordingly, MWFs are required to develop advanced treatments to conserve hydro-ecological resources. This study investigated the removal efficiency of ammonia nitrogen from MWFs according to operating time, applied voltage, and NaCl concentration using a Ti/IrO₂ electrode in a batch-type reactor. The experimental results showed that ammonia-nitrogen removal efficiencies without NaCl were 89% and 92% when voltage was adjusted to 15 and 20 V for 60 min and removal efficiency was 90% at 25 V for 40 min. Removal efficiencies of 10 mM NaCl were 4% and 2% greater than those of not adding NaCl at 15 V for 50 min and 20 V for 30 min.

Key Words

Electrochemical treatment, Metal working fluids, Electrolyte, Ammonia nitrogen, Ti/IrO₂

강준구 Jun-gu Kang , 손준익 Jun-ik Son , 민지수 Ji-su Min , 장미정 Mi-jeong Jang , 권영현 Young Hyun Kwon , 유하녕 Ha-nyoung Yoo , 고영재 Young-jae Ko , 권준화 Jun-hwa Kwon , 전태완 Tae-wan Jeon , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2016.33.8.810

Abstract

Various efforts have been made to increase use of renewable energy sources and reduce greenhouse gas emissions in Korea as economic and population growth have increased. Bio-energy is a renewable form of energy unlike fossil fuels and is not included in greenhouse gases because it is carbon neutral (sometimes referred to as “climate neutral”) and is exempted from total CO₂ emissions. In this study, we determined the low heating value (kcal/kg) and elemental composition using the biogenic content of “wood” and a solid recovered fossil fuel “polyethylene product” to confirm the solid recovered fuel value. Biomass content was also determined using the selective dissolution method and ¹⁴C-method (AMS). Additionally, we developed a gas sampling system to collect gases emitted after combustion at 850oC to determine biomass content by AMS.

Key Words

Biomass, AMS, SDM, Carbon isotope

최창식 Changsik Choi , 이채영 Chae-young Lee , 송영채 Young-chae Song , 윤영만 Youngman Yoon

DOI:10.9786/kswm.2016.33.8.819

Abstract

The purpose of this study was to investigate and analyze continuous operation of food waste resources at Dongdaemun Environmental Resources Center and to improve the overall operation of the dry anaerobic digester facility. Korean domestic food wastes consist of 18% total solid (TS) content but food waste is difficult to utilize for dry anaerobic digestion. Other operational trouble-shooting resulted from the inherent design, construction and operation of such a biomass generation facility based on 100% utilization of dewatered cake with 35% TS concentration as feedstock, causing the accumulation of unwanted solid residues. A materials flow analysis obtained from actual operation of the anaerobic digestion facility revealed that the organic material loading rate (OLR) and its residence time were 8.3 kg-VS/m³·day and 18.3 days, which adversely affected stable operation. The OLR was occasionally > 15,000 mg/L organic acid concentration and the facility shut down. Such anomalies drastically reduced biogas production and increased organic matter loading in the wastewater, which exceeded the legally allowed concentration limit. Operation of this facility has been normalized to the targeted facility capacity of 98 m³/day based on the results of this study.

Key Words

Dry anaerobic digestion, DRANCO (DRy Anaerobic COmposting), Food wastes, Dewatered cake recirculation process, Organic material loading rate (OLR), Dongdaemun environment and resources center