• Structural Engineering and Mechanics
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• v.86 no.5
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• pp.687-704
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• 2023

This study aims to examine the structural response of glass fibre-reinforced polymer (Glass-FRP) reinforced geopolymer electronic waste aggregate concrete (GEWC) compression elements under axial compression for sustainable development. The research includes the fabrication of nine GEWC circular compression elements with different reinforcement ratios and a 3-D nonlinear finite element model using ABAQUS. The study involves a detailed parametric analysis to examine the impact of various parameters on the behavior of GEWC compression elements. The results indicate that reducing the vertical distance of glass-FRP ties improves the ductility of GEWC compression elements, and those with eight longitudinal rebars have higher axial load-carrying capacities. The finite element predictions were in good agreement with the testing results, and the put forwarded empirical model shows higher accuracy than previous models by involving the confinement effect of lateral glass-FRP ties on the axial strength of GEWC compression elements. This research work contributes to minimizing the carbon footprint of cement manufacturing and electronic waste materials for sustainable development.

• Applied Chemistry for Engineering
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• v.35 no.5
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• pp.438-444
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• 2024

Lipid-extracted algae (LEA) cell residue is generated as an organic solid waste in the process of biodiesel production from microalgae, and its recycling or reuse is important in the aspect of waste minimization. In this study, the influence of the addition of LEA hydrolysate to Chlorella vulgaris (C. vulgaris) cultivation on cell growth and biodiesel production was investigated to seek a possible use of LEA as a carbon source. LEA was hydrolyzed by three different methods: acid hydrolysis, autoclave, and ultra-sonication. The resulting hydrolysates were supplemented with three background media: formulated defined medium (BG-11), organic liquid fertilizer (PAL1), and distilled water. Both cell growth and lipid production of C. vulgaris were improved under mixotrophic cultivation. By supplementing hydrolysates, biomass productivity was increased several folds because the LEA hydrolysates contained monosaccharides such as glucose and galactose. Lipid contents and biodiesel productivity were bestly increased in PAL1 medium supplemented with ultrasonication (UL) hydrolysate, from 11 to 25% after 14 days, while nitrate concentration was quickly reduced from 55 to below 10 mg/L. The suggested recycling option of the LEA to microalgae cultivation was helpful to improve biodiesel productivity as well as to reduce organic waste generation.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.231-239
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• 2003

In this study, the waste of landfill was treated using advanced enriched oxygen combustion system. The oxygen concentration of this study was 21%, 25%, 30% and 40% and the operating capacity was 200 g/min and the residence time was 10 minutes. As increased the oxygen concentration of combustion air. temperature of the incinerator was increased and the temperature was increased rapidly when the oxygen concentration was 30%. As increased the oxygen concentration, the NOx (ppm) of flue gas increase d for thermal NOx, however the CO (ppm) of flue gas decreased according to the increase of combustion efficiency . The optimum operation condition of incineration was obtained when the oxygen concentration is 30%${\sim}$40%. The unburned carbon of ash decreased from 10% to 4% when the oxygen concentration was increased from 21% to 30%, therefore the high combustion efficiency can be obtained if used the oxygen enriched combustion system.

• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.111-124
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• 1996

Composting of animal residues with weeds and waste papers as bulking agents was tested. Coorperative form of work with farmers, students, cleaning women and members of citizens' movement was attempted. The responses of participants for composting, through it's laboriousness and dirtiness, were favorable with feeling of doing good for social services. The temperature of compost was raised up to 83 $^{\circ}C$. in spite of cold winter weather after turning. The pH, water content, total carbon, total nitrogen and C/N ratio showed the similarity to stability steps of other usual composts. The contents of heavy metals were low except Cu in comparison with standard levels. The uses of waste papers as a bulking agent for composting of animal residues, especially for organic farming, would need more diverse investigations.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.561-564
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• 2005

Gasification has been regarded as a very important technology to decrease environmental pollution and to obtain higher efficiency. The gasification process converts carbon containing feedstock into a synthesis gas, composed primarily of CO and $H_2$. And the synthesis gas can be used as a source for power generation or chemical material production. Through more than nine years, IAE developed and upgraded several gasification/melting pilot plant system, and obtained a good quality synthesis gas. This paper illustrates the gasification characteristics and operation results of two 3 ton/day synthesis gas production facilities. One is entrained-bed slagging type coal gasifier system which is normally operated in the temperature range of $1,400\~1,450^{\circ}C,\;8\~10$ bar pressure. And the other is fixed-bed type gasification/melting furnace system using MSW and industrial wastes as a feedstock.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.260-265
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• 2004

Acid mine drainage(AMD) is one of the most serious environmental concerns associated with the mining industry around the world. The objective of this study is to assess the potential of sewage sludge as a carbon source for sulfate reducing bacteria and waste lime and steel slag as a neutralize agent for acid mine drainage bioremediation for use in permeable reactive materials. The study was performed using synthetic AMD in six column experiments. The effluent solution was systematically analysed throughout the experiments. The results of the study indicated that sewage sludge, waste lime and steel slag were the most effective for the AMD treatment as a permeable reactive materials.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.406-409
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• 2005

Since 2003, Korean government has restricted landfill application of organic waste, which shares approximately 56% of total waste sludge from municipal and industrial wastewater treatment plants. In addition, enforcement of the ocean disposal prohibition law is effective from 2005. Organic sludge was composted for the purpose of converting to organic fertilizer. After moisture content was regulated with bulking agents aerobic treatment performed. When composting was conducted, commercial and activated microbe materials, identified from soil were seeded in sewage sludge. Carbon dioxide production was increased sharply after 24 hours. Temperature and pH of compost reached to $66.2^{\circ}C$ and 8. Heavy metals were lower than their regulatory limits, which enable it to utilize as organic fertilizer.

• Textile Coloration and Finishing
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• v.4 no.3
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• pp.131-135
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• 1992

Quaternary aminized cellulosic adsorbents (C $A_{QA}$ ) which exhibit adsorption capacities for anionic dyestuffs for the treatment of colored waste water and re-use of the treated water were studied. The isotherms and thermodynamic parameters of C.I. Acid Orange 7, solution considered as a model of negatively charged coloring matters for C $A_{QA}$ , were determined. Batch method and flow method were employed to determine decoloring capacity of cellulosic adsorbents for Orange 7. The cellulosic adsorbents exhibited much better adsorption capacity than activated carbon. Furthermore the exhausted cellulosic adsorbents could be readily regenerated by washing with dilute sodium hydroxide.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.136-141
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• 2001

If we build new building after demolition of commercial building that is located in the downtown, it will be caused a social and environmental problem as wasting of resources and generating of waste. In this study, I investigated about remodel ins, this conclusion is given below. 1. Reconstruction cost is 2.1 times, and construction period is 1.4 times as much remodeling. So remodeling has an advantage. 2. For repairing and reinforcing timeworn building, we reinforced it as using carbon fiber sheet (girder, slab) and injecting method steel plate bonding Also, we tried to maintain efficiency of new building as using epoxy to protect concrete crack. 3. In the side of waste products and cost, remodeling has much more advantage than reconstruct. But demolition used construction period much. Because it had to be reused as repairing and reinforcing. And there was no difference between remodeling cost and reconstruct cost. If we develop research with enterprise.university.laboratory to exploit material and equipment and to train specialized engineer who will has a capacity to know construct repair and reinforce, it can be attribute to prevail remodeling in new construct market.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.286-291
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• 2001

As part of fundamental studies on the degradation of the organic compounds in industrial waste water, the photocatalytic degradation properties of the organic compound by means of the UV/TiO$_2$degradation process have been investigated. The test organic compound of acetic acid was chosen in this study. The testing of photo catalytic degradation were performed under various operation conditions such as TiO$_2$dosages, initial concentration of the organic, the aqueous pH's, etc. The effects of various parameters on the short time activity of the present acetic acid-UV/TiO$_2$system could be demonstrated from this investigation.