• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.91-98
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• 2017

The purpose of this study is to provide a design and operation technical guideline for meeting the appropriate design criteria to bio-gasification facilities treating organic wastes. 9 anaerobic digestion facilities which is normally operated during the field survey and 14 livestock manure farms were selected for precision investigation. the physicochemical analysis was performed on the moisture and organic contents, nutrients composition (carbohydrate, fat, protein), volatile fatty acids (VFAs), and nitrogen, etc. Volatile solids (VS) of organic wastes brought into the bio-gasification facilities were 2.81 % (animal manure only) and 5.92 % (animal manure+food waste), respectively. Total solids (TS) reults of samples from livestock farms were 5.6 % in piglets and 11~13 % in other kinds of breeding pigs. The actual methane yield based on nutrients contents was estimated to $0.36Sm^3CH_4/kgVS$ which is equivalent to 72 % of theoretical methane yield value. The optimum mixing ratio depending on the effect of the combined bio-gasification was obtained through the continuous stirred-tank reactor (CSTR) which is operated at different mixing ratio of swine manure and food waste leachate. The range of swine manure and food waste leachate from 60:40 to 40:60 were adequate to the appropriate conditions of anaerobic digestion; less than 100 gTS/, more than alkalinity of 1 gCaCO3/L, C/N ratio 12.0~30.0, etc.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.66-75
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• 2012

The objective of this study was to assess the effects of methanogenic bacteria-activated leachate recirculation method for enhancing waste stabilization and landfill gas production from a solid waste landfill. To simulate a conventional landfill (Lys-A), a landfill recirculated only fresh leachate (Lys-B), and two landfills recirculated leachate after pretreating with ASBR (Lys-C and Lys-D), four lysimeters were operated over a period of 4 years. Lys-D was recirculated two times of pretreated leachate volume than that of Lys-C. In the case of the landfill recirculated only fresh leachate and the landfill recirculated leachate after pretreating with ASBR, methane productions were increased until about 600 days, but there were not effect of leachate recirculation for enhancing methane production after about 600 days. It was assumed that leachate recirculation into fewer biodegradable organic wastes had not effect to enhance landfill gas production. Lys-C and Lys-D showed the highest performance for enhancing cumulative methane yield as well as acceleration waste stabilization. In cumulative methane yield, Lys-C (35.51 mL $CH_4/g$ VS) and Lys-D (36.12 mL $CH_4/g$ VS) were much higher than Lys-A (28.37 mL $CH_4/g$ VS) and Lys-B (30.07 mL $CH_4/g$ VS). In case of between Lys-B and Lys-C with the same recirculation rate, COD concentration in Lys-C was more rapidly decreased compared with that in Lys-B. This was attributed to the presence of methanogenic bacteria as well as dilution of inhibitory substances by the methanogenic bacteria-activated leachate recirculation. Therefore, the landfill recirculated leachate after pretreating with ASBR was found to be the most appropriate operating techniques for enhancing waste stabilization and landfill gas production.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.9 no.3
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• pp.169-179
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• 2011

There are two types of nuclear reactors in Korea and they are PWR type and CANDU type. The safe management of the spent fuels from these reactors is very important factor to maintain the sustainable energy supply with nuclear power plant. In Korea, a reference disposal system for the spent fuels has been developed through a study on the direct disposal of the PWR and CANDU spent fuel. Recently, the research on the demonstration and the efficiency analyses of the disposal system has been performed to make the disposal system safer and more economic. PWR spent fuels which include a lot of reusable material can be considered being recycled and a study on the disposal of HLW from this recycling process is being performed. CANDU spent fuels are considered being disposed of directly in deep geological formation, since they have little reusable material. In this study, based on the Korean Reference spent fuel disposal System (KRS) which was to dispose of both PWR type and CANDU type, the more effective CANDU spent fuel disposal systems were developed. To do this, the disposal canister for CANDU spent fuels was modified to hold the storage basket for 60 bundles which is used in nuclear power plant. With these modified disposal canister concepts, the disposal concepts to meet the thermal requirement that the temperature of the buffer materials should not be over $100^{\circ}C$ were developed. These disposal concepts were reviewed and analyzed in terms of disposal effective factors which were thermal effectiveness, U-density, disposal area, excavation volume, material volume etc. and the most effective concept was proposed. The results of this study will be used in the development of various wastes disposal system together with the HLW wastes from the PWR spent fuel recycling process.

• Journal of the Korean Ceramic Society
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• v.38 no.10
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• pp.908-913
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• 2001

Paper sludge Ash (PA) and Fly Ash (FA) wastes are usually land-filled for reclamation or substituted for cements as a resource. It could also offer some advantages when they are substituted for clay to preserve the environment. To recycle those wastes, the sintered specimen made of PA-FA-Clay system were examined to find the microstructure and physical properties. The ratio of clay to wastes was fixed as 30:70 by wt%, while PA to FA within waste portion were varied in the range of $1:6{\sim}7:0$. Those specimens were fired in $1150{\sim}1350^{\circ}C$. It was found that the relative density of sintered specimen was increased with amount of PA added at low sintering temperature (i.e, $1150{\sim}1200^{\circ}C$). This is due to increased amount of liquid during sintering. It is shown, however that at high sintering temperature ($1250{\sim}1350^{\circ}C$), the relative density of specimens was decreased with amount of PA added. This is because of overfiring phenomenon which may be able to induce an inhomogeneous microstructure and increased porosity. The mechanical properties of sintered specimen were depended upon the homogeneity of microstructure in accordance with SEM (Scanning Electron Microscopy) and pore size distribution analysis. For example, the compressive strength of 10PA-60FA-30Clay specimen sintered at $1225^{\circ}C$ was twice higher than that of 70PA-30Clay specimen even thought the relative density of those specimen was similar. This decreased strength of 70PA-30Clay specimen appears to be an inhomogeneity of microstructure due to overfiring.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.1-6
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• 2004

Agricultural recycling of livestock wastes by composting has lots of beneficial effects on crop production and soil fertility. Most of composts are made from pig manure and water content controller such as saw dust, bark, rice hulls etc. by aerobic processing. But the insufficient supply of saw dust, bark etc. cause the indiscreet use of industrial waste having heavy metals and toxic synthetic chemicals. This research investigated the present quality status of organic by-product fertilizers, and suggested the way of quality interpretation under the statistical approaches based on median, mean and weighted average value. Since the data of one hundred of samples for heavy metal contents (Cd, Pb, Cu, and Cr) and OM/N showed extremely left-skewed distribution, the median was more useful than the mean in representing the characteristics of distribiition for each items. The weighted average value will be a useful index for the quality based on the total amount of producing.

• Korean Journal of Construction Engineering and Management
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• v.15 no.6
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• pp.63-70
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• 2014

Deconstruction of the building must be applied firstly in order to improve recycling and reuse of construction wastes. In this study have done a case study for deconstruction of an apartment. All construction waste(CW) which will be generated during deconstruction was examined in each part of the building. Because drawing did not exist in most of the old building, we drew up floor plans of buildings. After analyzing these drawings, estimated quantities of CW. It was measured working time of labor and equipments for deconstruction and general demolition on each building of the apartment. In addition, it was proposed in the volume and weight per unit after analyzing detailed measurement of CW which was generated in the process of deconstruction and traditional demolition. It suggested recovery rate at a site, volume and weight conversion factors, and waste basic unit per area that based on the results of comparative analysis on the amount of CW which is calculated from drawing and generated at a site. These factors will be used fundamental materials for estimating quantities and treatment cost of CW, and scheduling of works.

• Journal of fish pathology
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• v.18 no.2
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• pp.187-195
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• 2005

Effluent of aquaculture industry has caused a growing concern regarding its environmental impact. We assessed the use of flounder farming sewage as supplement of diet, to minimize the impact of aquaculture on the environment or also establish the technique for the recycling of effluent sediment derived from land-based seawater fish farm. In order to investigate the effects of a fermented aquaculture waste on biochemical responses of olive flounder (Paralichthys olivaceus), fermented products of aquaculture wastes were used as test compounds that cause hepatic and renal stress through the induction of oxidative stress in liver and kidney. Hepatosomatic index (HSI), glutathione content and glutathione dependent enzyme were not significantly different and no correlation was found within the different types of fermentation condition or supplement concentration, except for significant increases in 50% fermentation group and 50% concentration group in case of glutathione peroxidase activity and HSI value, respectively. These results showed addition of fermented aquaculture sewage may be an economic artificial sources of diet for fish aquaculture practices without affecting the function and safety in view of biochemical examination.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.437-442
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• 2016

A new route for PBT (Poly butylene terephthalate) production from recycled PET (Poly ethylene terephthalate) has been explored. The route consists of glycolysis of PET (Poly ethylene terephthalate) wastes using 1,4-butandiol into BHBT oligomers and polycondensation of the oligomers into PBT oligomer. This process uses post-consumer or post-industrial recycled PET and converts it into high-end PBT type engineering thermoplastic via a chemical recycling process. Zink acetate was used as a catalyst for both glycolysis and polycondensation. Two types of reactor for the glycolysis, batch and semi-batch reactor, were investigated and their performances were compared. Semi-batch reactor removes ethylene glycol (EG) and THF (tetrahydrofuran) during the reaction. Amounts of EG and THF generated during the glycolysis reaction were measured and used as criteria for the reactor performance. Performance of semi-batch reactor was shown to be better than that of batch reactor. Optimum reaction condition for the semi-batch reactor was BD/PET ratio of 4, and reaction temperature of $220^{\circ}C$, giving high EG yield (max 91%) and low production of THF. In addition, it was confirmed that the molecular weight of PBT oligomer increases in accordance with the progress of the polycondensation reaction.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.870-878
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• 2010

We investigated the concentration and the sources of ubiquitous persistent organic pollutants [i.e., 17 toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 coplanar polychlorinated biphenyls (Co-PCBs), and 16 priority polycyclic aromatic hydrocarbons (PAHs)] in waste papers and lumbers from industrial complexes. The total concentrations in waste papers and lumbers ranged from 9.69~176.77 pg/g-dry and 0.14~0.25 pg/g-dry for 17 PCDD/Fs, 109.95~4097.25 pg/g-dry and 28.23~59.88 pg/g-dry for 12 Co-PCBs and 9.30~52.18 ng/g-dry and 0.82~1.82 ng/g-dry for 16 PAHs respectively. Generally, the concentration of these pollutants in waste papers was higher than those in waste lumbers. OCDD was dominant in waste papers and lumbers and the PCDD/F patterns of these samples were similar with that of stack gas. The distribution patterns of Co-PCBs in wastes were related with commercial PCB products, indicating the effect of commercial PCB products on ubiquitous environment. The diagnostic ratios of several PAH compounds in waste paper showed that they were related with pyrogenic sources.

• Clean Technology
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• v.26 no.3
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• pp.228-236
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• 2020

Korea has an economy based on manufacturing industrial fields, which produce high amounts of hazardous wastes, in spite of few landfill candidates, and a significant concern for fine airborne particulates; therefore, traditional waste management is difficult to apply in this country. Moreover, waste collection and accumulation have recently been intensified by the waste import prohibitions or regulations in developing nations, the universalization of delivery services in Korea, and the global COVID-19 crisis. This study thus presents a domestic waste management strategy that aims to address the recent issues on waste. The contents of the strategy as the main results of the study include the (1) improvement of the compatibility of the classification codes between the domestic hazardous waste and the international ones such as those of the Basel Convention; (2) consideration of the mixed hazard indices to represent toxicity from low-content components such as rare earth metals often contained in electrical and electronic equipment waste; (3) management application based on risks throughout the life cycles of waste; (4) establishment of detailed material flow information of waste by integrating the Albaro system, Pollutant Release and Transfer Register (PRTR) system, and online trade databases; (5) real-time monitoring and prediction of the waste movement or discharge using positional sensors and geographic information systems, among others; and (6) selection and implementation of optimal treatment or recycling practices through Life Cycle Assessment (LCA) and clean technologies.