변민우 Min-woo Byeon , 강홍식 Hong-sik Kang , 이영환 Young-hwan Lee , 최용혁 Yong-hyeok Choi , 한지훈 Ji-hun Han , 안종화 Johng-hwa Ahn

DOI:10.9786/kswm.2016.33.4.323

Abstract

This study investigated the enzymatic pretreatment of food waste (FW) using Viscozyme L to enhance reducing sugar (RS) production. Response surface analysis was used to study the effects of the pretreatment variables of temperature (T) (35-55℃) and incubation time (IT) (9-15 hr). The results indicated that the generated regression model represented the relationship between the independent variables and the responses. The RS production from FW was affected by IT rather than T. Within the design boundaries, a maximum RS yield (0.72 g/g of total solids of FW) was obtained at 44.5℃ and 13.7 hr.

Key Words

Enzymatic hydrolysis, Food waste, Optimization, Reducing sugar, Response surface analysis

조한나 Hanna Cho , 맹준호 Jun-ho Maeng

DOI:10.9786/kswm.2016.33.4.328

Abstract

More than 8 M tons of coal ash is generated from coal-fired thermal power plants every year, and the generation rate of coal ash has been increasing steadily recently. However, the recycling rate of coal ash is about 70%. It is time to introduce the beneficial use of coal ash. Much coal ash is used in mining applications and reclamation sites in the EU and the U.S. However, coal ash cannot be used at mine reclamation sites in Korea because of its legal limitations due to environmental concerns. Therefore, in this research, the eco-friendly use of coal ash at mine reclamation sites in Korea is presented. To develop the eco-friendly use of coal ash at mine reclamation sites in Korea, this study examined the beneficial use of coal ash at mines and the environmental issue of the specific use of coal ash at mine reclamations sites and carried out case studies on the use and management systems of coal ash in overseas countries and investigation of the present use of coal ash at mine reclamation sites in Korea.

Key Words

Coal ash, Beneficial use of coal ash, Mine, Mine reclamations sites, A society of resource recycling

연진모 Jin-mo Yeon , 전태완 Tae-wan Jeon , 강영렬 Young-yeul Kang , 정미정 Mi-jeong Jeong , 신선경 Sun-kyoung Shin , 김용준 Yong-jun Kim , 장미정 Mi-jeong Jang

DOI:10.9786/kswm.2016.33.4.338

Abstract

In this study, content and leaching tests of heavy metals (14 items) were analyzed to evaluate the recyclability of the sludge from wastewater treatment facilities. Additionally, this was compared with and examined with the standard of controlled waste, certification standards of compost materials, etc. In the results of the content test, Cr⁶⁺ (30.82 mg/kg) of waste from the leather, fur, and textile industries (EWC 04) and Cr⁶⁺ (103.13 mg/kg) of waste from the manufacture formulation, supply, and use of coatings (EWC 08) were higher than the proposed criteria of Cr⁶⁺ (20 mg/kg). The high level of Cr⁶⁺ concentration was observed because of the use of sodium dichromate and chromic anhydride in the materials of dyestuffs and pigments and ink in the EWC 04 and EWC 08 processes. The results on sludge in this study did not meet the standard of the Fertilizer Control Act and quality standard of fuels. In particular, the high levels of Pb and Cd was the main reason.

Key Words

Wastewater treatment sludge, Recycling, Characteristic, Inorganic substance, CN, Cr⁶⁺

신종선 Jong-seon Shin , 배달희 Dal-hee Bae , 주지봉 Ji Bong Joo , 박재현 Jaehyeon Park , 박재혁 Jae Hyeok Park , 김기영 Gi Yeong Kim , 선도원 Dowon Shun

DOI:10.9786/kswm.2016.33.4.347

Abstract

Bio-SRF (Bio-Solid Refuse Fuel) based on livestock waste has a low heating value and high moisture content. The concentration of toxic gas, such as SOx, NOx, and HCl, in the flue gas is changed according to the composition of fuel, which has been reported. Therefore, the study of fuel combustion characteristics is necessary. Additionally, the study of fuel firing characteristics is necessary. In this study, we investigated the combustion characteristics of the mixed firing of coal and Bio-SRF made from livestock waste in a circulating fluidized bed combustor (CFBC). The Bio-SRF of livestock waste was mixed with different ratios of coal based on the heating values when the coal was completely combusted in CFBC. In the results of the experiment, the combustor efficiencies of the calculated unburned carbon concentration in the fly ash were 98.87%, 99.04%, 99.64%, and 99.71% when the multi-firing ratio of livestock sludge increased from 100/0 to 70/30. In addition, the boiler efficiencies were 86.23%, 86.30, 87.24, and 87.27%. Through the experimental results, we identified that the mixed combustion of livestock sludge is not affected by boiler efficiency. We have systematically investigated and discussed the temperature changes of an internal combustor, compositions of flue gases, solid ash characteristics, and the combustion and boiler efficiency during the mixed firing of coal and Bio-SRF.

Key Words

CFBC, Combustion, Mixed fuel, Bio-SRF

권영현 Young-hyun Kwon , 손준익 Jun-ik Son , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2016.33.4.357

Abstract

As shown in the analysis of energy recovery management policies and energy recovery rate calculation methods in Europe and Japan, it is necessary to achieve sustainable technical development and review and supplement relevant systems in Korea to maximize the thermal energy recovery rate of waste incineration facilities. By taking into account the energy (heat or power) sold in high-demand places and the energy that is independently generated and used for other processes (sludge-drying facilities, convenient facilities for local residents, etc.), it is necessary to devise criteria for a reasonable energy recovery rate. Additionally, in calculating a lower heating value of the total waste injected in an incinerator, it is necessary to review an objective and scientific lower heating-value calculation formula and calculation method that exclude policy factors following the example of the EU.

Key Words

Incineration heat, Energy recovery, R1-formular, Net calorific value

박진우 Jin Woo Park , 박태순 Tae Soon Park

DOI:10.9786/kswm.2016.33.4.366

Abstract

This study presents flowable fill material using collected CO₂ byproduct, which prevents geotechnical sinking related to underground utilities in the vicinity of downtown areas. The physical and mechanical characteristics of calcium carbonate found using laboratory tests (the uniaxial compressive strength test, comparison of the shear base of dynamic behavior and restriction pressure, the freeze-thawing test) on 3, 7, 14, 28, and 56 days of the flowable fill were investigated and analyzed. The correlations of the unconfined strength, elastic modulus, flow, and w/c were suggested as evaluation indicators of the mechanical characteristics for the calcium carbonate flowable fill.

Key Words

Calcium carbonate(CaCO₃), Geofill, Flow, Uniaxial compression

박영수 Yeong Su Park , 구재회 Jae Hoi Gu , 이병선 Byung Sun Lee

DOI:10.9786/kswm.2016.33.4.374

Abstract

The chemical kinetics of the steam reforming of the pyrolysis oil of polypropylene (PP) over a ruthenium-based catalyst has been examined as a function of pyrolysis oil and steam partial pressures at various temperatures. The activation energy of steam reforming over Ru/Al₂O₃ catalyst is 136 kJ/mol, and the reaction orders of pyrolysis oil and steam are 0.42 and 0.24, respectively. Fitting the experimental data to the Langmuir?Hinshelwood expression shows that the steam-reforming reaction probably proceeds via the dissociative adsorption of pyrolysis oil and steam on two different sites.

Key Words

Ruthenium, Kinetic, Steam reforming, Waste plastics, IGFC, Gasification

변민우 Min-woo Byeon , 김정원 Jung Won Kim , 안종화 Johng-hwa Ahn

DOI:10.9786/kswm.2016.33.4.383

Abstract

This study aimed to describe the mechanism and reaction characteristics of the adhered mortar removal of recycled aggregate (RA) using microwave irradiation (700 W) and a mixed solution of HCl and H₂O₂. The HOCl concentration increased to 29.7 M at 35℃ and 40 min of reaction time without RA in the mixed solution, which shows that HCl reacts with H₂O₂ to form HOCl and water. However, after nitrogen purging, the HOCl concentration decreased to 2.71 M in 20 min, which proves indirectly that HOCl reacts with HCl to form Cl₂ and water. The HOCl concentration decreased from 29.7 M to 1.88 M at 35℃ in 40 min with RA in the mixed solution, and the Ca²⁺ concentration increased to 9,750 mg/L, which demonstrates indirectly that mortar mainly composed of Ca(OH)₂ reacts with Cl₂ to form Ca(OCl)₂ and CaCl₂. The reaction rate (k) with microwave heating was about 2.3 times faster than that with conventional heating, and k at a reaction temperature of 50℃ was about 1.3 times faster than that at 35℃. The treated RA was improved in density, water absorption, abrasion loss, and absolute volume.

Key Words

Adhered mortar, Hydrogen peroxide, Hydrochloric acid, Mechanism, Recycled aggregate

정우진 Woo Jin Chung , 홍성민 Seong Min Hong , 김한래 Han Lae Kim , 장순웅 Soon Woong Chang

DOI:10.9786/kswm.2016.33.4.391

Abstract

Solid-liquid separation is important for securing safe runoff quality in the biological treatment process. In particular, the method for determining sludge settlement characteristics using SVI, which is a parameter, evaluates the precipitation features of sludge in an aeration tank and secondary precipitation tank and is a simple and widely used method. However, in methods using SVI, the accumulation of objective data is usually not possible, since the subjective judgment of operators is mainly involved in this evaluation method. Therefore, the automation of SVI measurement is required to improve the determination method of sludge settlement using SVI. In this study, an automatic measurement system of SVI using optics was developed. To evaluate the reliability of the measurement system, a visual inspection test was performed in parallel with our suggested SV30 auto-measurement system using actual sludge and a similar tendency in the results was obtained. Using this suggested SV30 automation system, the indirect determination of MLSS (Mixed-Liquor-Suspended-Solids) activation states of the aeration tank and precipitation tank is also expected to be possible. Through the test results, it was verified that the reliability of SVI determination was increased by identifying the effect of outside light after performing a test under external light interference.

Key Words

Optical system, SV₃₀, Sludge, Automatic detecting, SVI

정승현 Seung Hyun Jeong , 정병곤 Byung Gon Jeong

DOI:10.9786/kswm.2016.33.4.398

Abstract

A manufacturing method is proposed for a sorbent material comprised of functional ceramic loess balls mixed with food waste and regenerated activated carbon. The physical characteristics and adsorption performance were also evaluated. Adding activated carbon improved the porosity and increased the specific surface area of the balls. The iodine-adsorbing capacity was evaluated with different mixing ratios of activated carbon. The capacity was improved as the mixing ratio was increased. The activated carbon was regenerated through a high-temperature burning process after reaching the break-through point. A column test was conducted to examine the methylene blue adsorption, and the adsorption rate also increased with the activated carbon mixing ratio. At mixing ratios of above 5%, the adsorption rate showed a high increase in the early stage and reached equilibrium after 6 minutes of reaction. However, it was impossible to reach the equilibrium state without activated carbon in the loess balls. Thus, it is apparent that activated carbon plays an important role in improving the adsorption efficiency. The optimum mixing ratio of activated carbon was 5%. At this ratio, the iodine adsorption rate showed a moderate rise, the adsorption efficiency was relatively high, and the methylene blue adsorption reached equilibrium.

Key Words

Sorbent, Food wastes, Regenerated activated carbon, Functional ceramic loess ball, Iodine adsorption capacity, Methylene blue adsorption test

김진관 Jin Gwan Kim , 이훈상 Hoonsang Lee , 오민아 Minah Oh , 김형욱 Hyeong-wook Kim , 이명호 Myungho Lee , 이재영 Jai-young Lee

DOI:10.9786/kswm.2016.33.4.404

Abstract

The purpose of this study was to analyze the physicochemical characteristics of bottom-ash recycling from municipal solid waste incineration (MSWI) and investigate the possibility of the use of bottom ash for Lightweight Aggregate for Structural Concrete and Bottom Ash Aggregate for Road Construction according to Korean Industrial Standards (KS). Samples were taken from the MSWI bottom ash collected at the resource recovery facilities “A” and “B.” In the results, both samples did not satisfy the criteria of the particle sizes. In particular, the two samples failed to comply with the physical and chemical characteristics criteria of the Lightweight Aggregate for Structural Concrete. On the other hand, both bottom ash samples met the physical characteristics criteria of the Bottom Ash for Road Construction. Therefore, the recycling of Bottom Ash Aggregate for Road Construction can be more a suitable method for recycling, provided that proper pre-treatment as a screening process for bottom ash is performed.

Key Words

Municipal solid waste, Bottom ash, Zero waste, Recycling, Aggregate

박세원 Se-won Park , 서용칠 Yong-chil Seo , 이장수 Jang-soo Lee , 유흥민 Heung-min Yoo , 양원석 Won-seok Yang , 강재준 Jae-jun Kang

DOI:10.9786/kswm.2016.33.4.410

Abstract

The utilization of renewable energy will be an inevitable situation in the future because of the acceleration of climate change and depletion of fossil fuels. Waste and biomass are major sources of renewable energy. In the near future, biomass will become the main resource of renewable energy in the world. However, in case of Korea, obtaining a stable supply of biomass is difficult. To overcome this problem, we need to import biomass from other countries. Palm empty fruit bunch (EFB) is known to be a good biomass resource, which is treated by either landfill or incineration in Indonesia and Malaysia. EFB could be used as feedstock for gasification for energy recovery as a gas fuel. Generally, biomass gasification has more stable operation than waste gasification. Nevertheless, biomass gasification generates lots of tar in syngas because of the lignin content in biomass, which may cause problems for gas engines and other processes. In this study, gasification experiments as well as qualitative analysis were conducted for determining syngas characteristics with tar content. Tar sampling and analysis were performed under various conditions by changing the flow rate, sampling time, and sampling gas flow. Measuring the tar content in syngas during the gasification process was also proposed

Key Words

Gasification, Tar in syngas, Palm mill EFB, Tar analysis