• Resources Recycling
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• v.18 no.3
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• pp.3-10
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• 2009

This paper will introduce the study which is the solidification and reduction of $CO_2$ green house gas, by using inorganic industrial wastes such like waste cement, steel making slag, incineration ash and so on. These inorganic wastes contain a large quantity of CaO content in common, which is easily reacted with CaO resulting in formation of $CaCO_3$. It will be suggested in this study that the necessary of the reduction and solidification of $CO_2$ gas with using industrial inorganic wastes is for building the Korea carbon storage model in this study.

• Clean Technology
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• v.13 no.2
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• pp.134-142
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• 2007

In this study, two methods to evaluate the disassemblability of the parts are proposed, which are constructed from the concepts of ease-of-disassembly and disassembly time. A method to evaluate the disassemblability of the products is consequently developed using the concept of minimum parts. The methods are applied to evaluate the disassemblability of computer cases. The results show the conclusions that the new model has less disassemblability than the old one. These methods are expected to be used for the evaluation of the possibility of remanufacturing and recycling of a part.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.219-220
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• 2021

It is considered that the construction industry is one of the pivotal players in the national economy in terms of Gross Domestic Production (GDP) and employment. Behind the positive role of this industrial sector to the national economy, the construction industry generates approximately 50 % of the total waste generation from all the industrial sectors. There are several measures to mitigate the adverse impacts of the construction waste such as reduce, reuse and recycle. Recycling would be one of the effective strategies for waste minimisation, which would be able to reduce the demand upon new resources as well as enhance reusing the construction materials on sites. The automated construction waste classification system would make it possible not only to reduce the amount of labour input but also mitigate the possibility of errors during the manual classification process. In this study, we proposed an automated waste segmentation and classification system for recycling the construction and demolition waste in the real construction site context. Since the practical application to the real-world construction sites was one of the significant factors to develop the system, a YOLACT (You Only Look At CoefficienTs) algorithm was chosen to conduct the study. In this study, it is expected that the proposed system would make it possible to enhance the productivity as well as the cost efficiency by reducing the manpower for the construction and demolition waste management at the construction site.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.23-33
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• 2020

Marine algae(Macro algae) are easily bio-degradable, and by-products are available as feed and fertilizer. The biomass of marine algae has higher CO2 absorption capacity than the wood system, and is highly valuable in use due to its fast growth speed and wide cultivation area without special cost for raw material production. In 2018, Marine algae production was 1,722,486ton, such as Saccharina japonica, Undaria pinnatifida and Porphyra tenera, the large amounts of by-products have been generated in the food processing facilities for commercialization. In this study, Saccharina japonica, Undaria pinnatifida were collected in the south coast region and Porphyra tenera was collected in the west coast region. The theoretical methane potential and biochemical methane potential(BMP) were analyzed, and Modified Gompertz model and Parallel first order kinetics model were adopted for the interpretation of the cumulative methane production curves. The theoretical methane potential of Saccharina japonica, Undaria pinnatifida and Porphyra tenera were 0.393, 0.373 and 0.435 N㎥/kg-VS, respectively. BMP obtained by the Modified gompertz model 0.226, 0.227, and 0.241 N㎥/kg-VS for Saccharina japonica, Undaria pinnatifida and Porphyra tenera, respectively. And BMP obtained by the Parallel first order kinetics model were 0.220, 0.243, and 0.240 N㎥/kg-VS for Saccharina japonica, Undaria pinnatifida and Porphyra tenera, respectively.

• Journal of the Korea Institute of Building Construction
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• v.14 no.1
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• pp.54-60
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• 2014

The purpose of this study is to examine whether cementitious powder separated from waste concrete can be used as an alternative raw material to limestone and reduce the usage of natural resource (limestone) and $CO_2$ emission based on recycling cementitious powder from waste concrete. Experiments actually analyzed the chemical composition of cementitious powder and performed hyperthermia analysis, measurement of free CaO and XRD analysis to measure the degree of recovery of hydration in the model of cementitious powder manufactured based on chemical composition. These were performed in each cementitious powder model at different calcination temperatures such as $900^{\circ}C$, $1200^{\circ}C$, $1300^{\circ}C$, $1400^{\circ}C$ and $1450^{\circ}C$. Through the experiments, it was found that the recovery of hydration was at a level which can be used as the alternative raw material for limestone, but the replacement ratio was directly affected by the degree of mixing of fine aggregate in less than $150{\mu}m$, which cannot be separated from cementitious powder. It was shown that there was no difference in the production of compounds involved in hydration at calcination temperatures of $1200^{\circ}C$ or higher. Therefore, to pursue the replacement of limestone and reduction of greenhouse gas by recycling cementitious powder, the development of technology to efficiently separate aggregate fine powder is required.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.125-128
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• 2000

A recycling reactor system operated under sequential anoxic and oxic conditions for the swine wastewater has been developed, in which piggery slurry is fermentatively and aerobically treated and then part of the effluent recycled to the pigsty. This system significantly removes offensive smells (at both pigsty and treatment plant), BOD and other loads, and appears to be costeffective for the small-scale farms. The most dominant heterotrophs were Alcaligenes faecalis, Brevundimonas diminuta and Streptococcus sp. in order while lactic acid bacteria were dominantly observed in the anoxic tank. We propose a novel monitoring system for a recycling piggery slurry treatment system through neural networks. Here we tried to model treatment process for each tank(influent, fermentation, aeration, first sedimentation and fourth sedimentation tanks) in the system based on population densities of heterotrophic and lactic acid bacteria. Principle component analysis(PCA) was first applied to identify a relation between input(microbial densities and parameters for the treatment such as population densities of heterotrophic and lactic acid bacteria, suspended solids (SS), COD, $NH_3-N$, ortho-P, and total-P) and output, and then multilayer neural networks were employed to model the treatment process for each tank. PCA filtration of input data as microbial densities was found to facilitate the modeling procedure for the system monitoring even with a relatively lower number of input. Neural networks independently trained for each treatment tank and their subsequent combinatorial data analysis allowed a successful prediction of the treatment system for at least two days.

• Journal of Sensor Science and Technology
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• v.9 no.2
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• pp.127-133
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• 2000

We propose a novel monitoring system for a recycling piggery slurry treatment system through neural networks. Here we tried to model treatment process for each tank(influent, fermentation, aeration, first sedimentation and fourth sedimentation tanks) in the system based on population densities of heterotrophic and lactic acid bacteria. Principle component analysis(PCA) was first applied to identify a relation between input(microbial densities and parameters for the treatment) and output, and then multilayer neural networks were employed to model the treatment process for each tank. PCA filtration of input data as microbial densities was found to facilitate the modeling procedure for the system monitoring even with a relatively lower number of input. Neural networks independently trained for each treatment tank and their subsequent combinatorial data analysis allowed a successful prediction of the treatment system for at least two days.

• Resources Recycling
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• v.23 no.6
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• pp.30-39
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• 2014

The trajectories of PCB(Printed Circuit Board) particles in the corona discharge electrostatic separation was simulated. The PCB particles are prepared by crushing bare board, which disassembled from electronic components, consist mostly of copper and FR-4(Flame Retardant Level-4) Firstly, a model was established for calculating of detachment points of PCB particles from the rotating electrode in separator. The model of detachment points was derived from equilibrium of force such as gravity force, centrifugal force, electrostatic force. The trajectories of particles after detachment was calculated by acceleration derived from time-integrating method of motion equation. In this simulation, particle size, supplied voltage, rotation speed of rotating roll electrode and angle of induction electrode were adopted as variables. While the trajectories of FR-4 particles were affected by all variables, rotation speed of rotating roll electrode was dominant variables affecting trajectories of copper particles.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.2
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• pp.27-34
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• 2014

Kinetic and isotherm properties of the cadmium adsorption onto calcium sand and granite soil were evaluated by batch experiments. The pHs of calcium sand and granite soil were 9.51 and 6.33, respectively, showing that the precipitation of heavy metals can be occurred due to the increase of pH when the calcium sand is used as an adsorbent. The pseudo-second-order model described the adsorption kinetics satisfactory with correlation coefficients over 0.999. The equilibrium adsorption capacities of calcium sand and granite soil were 2.10 and 2.16 mg/g, respectively. The adsorption isotherm followed the Freundlich isotherm model, indicating the cadmium adsorbed onto the heterogeneous surfaces of adsorbents.

• Resources Recycling
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• v.17 no.3
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• pp.56-61
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• 2008

The kudzu has been investigated as an adsorbent for treatment of Cr(VI)-containing wastewater. The specific surface of kudzu was analyzed to be $189.91m^2/g$ and its major composition were found to be nitrogen and oxygen. It was observed that adsorption reaction for Cr(VI) on kudzu meets 1st order in kinetics and Langmuir Model in equilibrium. As the pH of wastewater was increased, the adsorbed amount of Cr(VI) onto kudzu was increased due to the pre-combination of $OH^-$ with adsorbent and the efficiency of adsorption was found to be 60% when real electroplating Cr(VI)-containing wastewater was applied.