• Applied Chemistry for Engineering
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• v.8 no.1
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• pp.99-107
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• 1997

This study Provides the treatment methods of liquid wastes from the dissolution/purification process of nuclear fuel raw material and the fabrication process of nuclear fuel powder. One of the treatment methods is to process liquid waste from uranium raw material dissolution/purification process. This waste, of the strong acid, can be reused to dissolve the fine ADU particles in filtrate which is ADU waste of pH 8.0 converted from AUC waste after recovery of uranium. To dissolve the fine ADU particles, ADU filtrate was pretreated to pH 4.0 with the dissolution/purification waste, and then mixed with the lime to pH 9.2 and aged for 30 minutes. From this processing, uranium content of the filtrate was decreased to below 3ppm. The waste from fuel powder fabrication is emulsified solution dispersed with fine oil droplets. This emulsion was destroyed effectively by adding and mixing the nitric acid with rapid heating at the same time. After this processing, $Na_2U_2O_7$ compound is produced by addition of NaOH. Optimum condition of this processing was shown at pH 11.5, and uranium content of the filtrate was analyzed to 5ppm. To remove the trace of uranium in the filtrate, lime should be added. Otherwise, 4N nitric acid was used to destroy the emulsion directly, and then lime was added to this waste. Uranium content of the treated filtrate was below 1 ppm. In addition to these wastes, the trace of uranium in filtrate after recovery of uranium from the AUC waste which is produced during PWR power preparation, is treated with NaOH to takeup fluorine(F) in the waste because fluorine is valuable and toxic material. In the finally treated waste, uranium was not detected.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.101-109
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• 2009

This CW(Construction wastes) are increasing as construction industry is growing, so many countries make efforts to recycle CW. Korea also made a stipulation for recycling CW. But the main content of this stipulation is for using recycled aggregates. Advanced countries try to increase reuse rate of not only recycled aggregate but also other kinds of wastes. So they are adopting SDM(separating dismantlement) method and we are also planning to make the system for SDM. This study is about SDM analysis through construction field investigation and difference analysis between SDM and UDM comparing predictive amount by UDM with real generated amount by SDM. First, the generated amount of construction wastes by SDM is more than estimated amount by UDM, and mixed waste was specially reduced more than UDM. The warehouse is easier than the office building to applicate SDM. But still there is no manual for SDM in the site, so establishment of SDM is demanded.

• Korean Journal of Construction Engineering and Management
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• v.8 no.6
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• pp.150-158
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• 2007

As the amount of $CO_2$ emission in Korea is ranked 9th and the increasing rate of $CO_2$ emissions highest in the world, it is strongly necessary to devise methods to decrease the amount of $CO_2$ in each industry as the basis of establishing environmentally sustainable production system. This paper aims to identify the characteristics of $CO_2$ emissions from construction wastes throughout the simplified LCA (Life Cycle Assessment) and suggest the strategic guideline for the construction waste management plan to decrease $CO_2$. As a result of LCA on the case of a high-rise residential building project, total sum of $CO_2$ emission generated from construction wastes appeared as 6,818,123kg-$CO_2$ and $CO_2$ emission per unit floor area as 21.01kg-$CO_2/{\beta}{\ge}$. The principal waste materials generating more than 95% of $CO_2$ are materials such as reinforcing bar, temporary materials, cement, ready-mixed-concrete, concrete products, and tile, which have relatively high unit emission rate of $CO_2$ in the process of production. Besides, more than 92% of $CO_2$ was generated from the activities such as structure work, plaster work, temporary work, and tile and stone work, which are generally executed in the early phase of the whole construction period. Reflecting these results, the guideline for the construction waste management plan was recommended. If the waste management plan is established considering the guideline suggested, there would be high potential to decrease the amount of $CO_2$ generated from construction wastes.

• Resources Recycling
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• v.16 no.5
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• pp.71-76
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• 2007

The mixed plastic waste generated from households after hand-picking and/or mechanical sorting processes amounts to 1,750,000 ton in 2006, and most of these waste are finally end up with landfill and/or incineration due to the lacks of separation technologies and economical reasons. The mixed plastic wastes can not be used as raw materials for chemical and/or thermal recycling processes because of their high content of PVC(upto 4.0 wt.%). In the present research, gravity separation system has been developed to remove PVC from the mixed plastic waste and to recover the PO-type plastics. This system mainly consists of air classification, magnetic separation, one-step crushing, feeding system at fixed rate and wet-type gravity separation system. The gravity system based on centrifugal separation has been developed at capacity of 0.5 ton/h and it consists of mixing, precleaning, separation, dewatering, recovery system and wastewater treatment system, etc. The main objective of this process is to achieve high separation efficiency of polyolefins with less than 0.3 wt.% PVC content and less than 10% moisture content in the final products. In addition, a crushing unit of with 8 rotor system is also developed to improve the crushing efficiency of soft-type plastics. The system with a capacity of 1.0 ton/h is developed and operational results are presented.

• Journal of Chitin and Chitosan
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• v.23 no.4
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• pp.285-292
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• 2018

In this study, for the purpose of decomposing food waste, the strain was screened from traditional fermented food and soils. The enzyme activity (protease, amylase, cellulase, lipase) experiment was carried out using the paper disc method in 212 strains isolated from 5% NaCl media. Among them, only the strains having enzyme activity of more than 2 (soil) or more than 4 (traditional fermented food) with the halozone of enzyme activity of 15 mm or more were selected first, and microorganism identification through 16S rRNA sequencing was performed. Finally, were identified such as Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus siamensis, Bacillus licheniformis, Bacillus aquimaris, Bacillus megaterium, Bacillus koreensis, Bacillus stratoshericus, Bacillus aryabhattai, Bacillus safensis, Marinobacter hydrocarbonoclasticus. 11 species of mixed strains were confirmed that the culture time was 24 hours, the incubation temperature was $30^{\circ}C$ and the optimum pH was 7.0. In order to confirm the degree of decomposition of standard food wastes (100 g) by treating 11 kinds of mixed strains (25%), solid content of more than $2000{\mu}m$ was determined to be 103 g for the sterilized water group and 18 g for the mixed strains group. And the rest was decomposed to a size of less than $2000{\mu}m$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.296-306
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• 2014

This study was conducted to survey and analyze the quantity of various organic wastes and to vitalize the utilization of agri-food by-products as raw materials for Total mixed ration (TMR), to improve feed cost savings and the quality of animal products. On-the-spot obstacles for animal farmers, along with legal and institutional alternatives are presented. The results are as follows. First, organic wastes in Korea are managed by the Allbaro system created in the Wastes Control Act, which processes 10,488 tons of cooking oil waste, 832,493 tons of animal and plant residues, 5,740 tons of animal carcasses, 1,171,892 tons of animal residues, and 2,172,415 tons of plant residues including 12,905 tons of rice hull and bran, for a total of 4,205,931 tons. Raw materials for TMR, namely rice hulls and bran as well as plant residues, accounted for 51.7% of the total national organic waste. The top 10 municipalities process 76~100% of all organic wastes and a supply management system is needed for the waste. Second, the 10 major agri-food by-products used as raw materials for TMR are bean curd by-product, rice bran, oil-cake, brewers dried grain, Distiller's Dried Grains with Solubles (DDGS), barley bran, soy sauce by-product, citrus fruit by-product, mushroom by-product and other food by-product (bread, noodles, snacks, etc.). Third, the biggest difficulties in using agri-food by-products are legal obstacles. Because agri-food by-products are regulated as industrial wastes by the Waste Control Act, animal farmers that wish to use them have legal reporting obligations including the installation of recycling facilities. To enable the use of agri-food by-products as raw materials for TMR, waste management system improvements such as 'the end of waste status' and the establishment of more than 10 public distribution centers nationwide are deemed essential.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1654-1660
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• 2009

Two different cutting-oils from H and B companies which are sold as an eco-friendly cutting-oils were selected and the biodegradability of these commercially available cutting-oils was evaluated by the sequencing batch reactor (SBR) processes. The cutting-oil wastes ($H_1$) pre-treated by coagulation/flocculation was used as an influent to SBR. When the F/M ratio was operated 0.04 to 0.08kgCOD/kgMLSS d, removals of $BOD_5$and $COD_{Cr}$were above 97% and 91%, respectively. T-N and T-P removals were above 76% and 81%, respectively. If the diluted cutting-oil wastes ($B_1$) was used as an influent of the SBR, $COD_{Cr}$removals were above 77% at the F/M ratio of 0.01-0.02kgCOD/kgMLSS d. After the cutting-oil wastes was treated by coagulation/ flocculation ($B_2$), $COD_{Cr}$removals was above 85%. If the pre-treated cutting-oil wastes were mixed with a synthetic wastewater ($B_3$) and fed into the SBR in order to mimic the real wastewater treatment plant situation, $BOD_5$and $COD_{Cr}$removals were above 97%, 91%, respectively. T-N and T-P removals were above 79% and 76%. The ratio between $BOD_5$and $COD_{Cr}$, ($COD_{Cr}$-$BOD_5$)/$COD_{Cr}$, indicating the biodegradability of effluent of the SBR, was calculated to 85% and 61%. This means that significant amounts of non-readily-biodegradable organic compounds in the effluent of $H_1$, $B_3$are still present.

• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.453-460
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• 2009

In order to provide fundamental data for developing high-grade(high-quality and low-pollution) Refuse Derived Fuel(RDF), we analyzed caloric value and HCl content by Municipal Solid Waste(MSW) type. The caloric value was analyzed using calorimeter and HCl content was analyzed using mercury(II) thiocyanate method. In case of paper type the caloric value was 3,060~3,608kcal/kg and the HCl content was 239~6,135ppm. In case of vinyl-plastics the caloric value was 5,946~9,888kcal/kg and the HCl content was 429~455,771ppm. According to the result of quality assessment by MSW type, the calroric value of vinyl-plastics type was showed higher than that of paper type and in case of HCl content the paper type was showed lower than vinyl-plastics type. So, We mixed paper and plastic wastes. The caloric value of mixed MSW(paper and plastics) was 5,046~9,125kcal/kg and the HCl content was 239~6,135ppm. Also, The caloric value of packaging waste(film-plastics) was 5,982~8,045kcal/kg. Therefore It is possible to develop high-grade Refuse Derived Fuel through suitable mixing of paper and plastic in municipal solid waste.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.307-311
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• 2014

This study investigated the effects of polyurethane foam on continuous hydrogen production from mixed wastes. Molasses was co-fermented with non-pretreated sewage sludge in a sequencing batch reactor. The results indicated that the addition of polyurethane foams as a microbial carrier in the reactor mitigated biomass loss at HRT 12 h, while most of the biomass was washed out during the operation period with no carrier. There was a stable hydrogen production rate of $0.4L-H_2/l/d$ in the carrier-sequencing batch reactor. Suspended biomass in the carrier-reactor indicated it possessed the highest specific hydrogen production rate ($241{\pm}4ml-H_2/g\;VSS/d$) when compared to that of biomass on the surface ($133{\pm}10ml-H_2/g\;VSS/d$) or inner carrier ($95{\pm}14ml-H_2/g\;VSS/d$).

• Resources Recycling
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• v.9 no.6
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• pp.45-52
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• 2000

Generally, the residues of EAF's dusts treated by reduction process at high temperature are disposed. If the residues can be recycled as iron sources of EAF by upgrading their iron contents, it can be expected to reduce the amounts of disposed wastes and the environmental impacts. Reduction of EAF's dusts mixed with millscale was carried out in rotary hearth furnace to upgrade iron contents of reduction residues. Dusts should be reduced rapidly to protect from reoxidation of reduced iron residue which can be reoxidized at high temperature. In our experimental conditions, optimum reduction time was about 40min. and iron contents of the residues were increased with increasing mixing ratio of millscale and upgrade to 85% at 50%wt mixing ratio. Zinc and lead contents in residues were about 3% and 0.5% respectively. The residues reduced rapidly must be recycled in EAF because heavy metal elements in the residues can be extracted easily and contaminate air and water.