• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.107-113
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• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.109-124
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• 1990

A rapid processing method for fish sauce of high quality stability and favorable flavor was investigated using mackerel waste as starting material. The chopped waste was homogenized with water and hydrolyzed by commercial proteolytic enzymes such as Complex enzyme-2000($2.18\cdot10^4$ U/g solid, Pacific Chem. Co.) and Alcalase ($1.94\cdot10^4$ U/g solid, Novo) in a cylindrical vessel with 4 baffles and 6-bladed turbine impeller. Optimal pH and temperature for the hydrolysis with Complex enzyme-2000 were 8.0 and $50^{\circ}C$, and those with Alcalase were 9.0 and $55^{\circ}C$. In both cases, the reasonabe amount of added water and enzyme concentration based on the waste weight were $40\%,\;3\%$ and hydrolyzing time was 100 min. Thermal treatment of the hydrolysate with $6\%$ of invert sugar for 2 hours at $90^{\circ}C$ was adequated to inactivation of the enzymes and pasteurization of the hydrolysate. Flavor, taste and color of the hydrolysate were improved during the thermal treatment in which the browning reaction products might participate and result in antioxidative and bactericidal effects. Combined use of $0.005\%$ of Caryophylli flos with $6\%$ of invert sugar was also effective for the improvement of taste. Yield of the fish sauce based on the total nitrogen of the raw waste was $93.7\~94.9\%$, and $87.6\~87.9\%$ of the total nitrogen in the fish sauce was in the from of amino nitrogen. The pH, salinity and histamine content of the fish sauce prepared with $15\%$ of table salt were $6.1\~6.2$, $14.0\~14.5\%$ and less than $10mg\%$, respectively. The fish sauce was stable on bacterial growth during the storage of 60 days at $26\pm3^{\circ}C$ and the quality was also maintained.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.11-22
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• 2014

The buffer capacity of food waste lowers during the collecting and transportation period. Food waste usually shows deficiency of micro nutrients especially molybdenum(Mo) and cobalt(Co). Therefore, food waste can be considered as a good mixture of livestock waste to enhance methane production. The objective of this study was to investigate the correlation between properties of substrates (local food waste and livestock manure) and methane yields for successive anaerobic fermentation process and its stable management. Food wastes were taken at an intermediate storage or treatment system provided by eight local authorities (Gangnam, Gangdong, Gwanak, Guro, Dongjak, Songpa, Yeongdeungpo, and Younsan) in Seoul. The solid content and potential methane yield of food wastes were average of 16% and $446.6STP-m{\ell}/g-VS$ (range from 334.8 to $567.5STP-m{\ell}/g-VS$) respectively. As for the beef cattle manure, the solid content and potential methane yield had an average of 26% and $280.6STP-m{\ell}/g-VS$ respectively. Potential methane yield had a positive correlation with fat content, and hydrogen content and a negative correlation with carbohydrate content ($r^2>0.8$). Therefore, the potential methane yield can be predicted based on the substrate characterization results with reasonable accuracy. Further research may be needed to investigate the relation of the properties of the mixture substrate and methane production rate. The mixtures may include food waste, livestock waste, and bulking agents (saw dust, rice hull, or agricultural byproducts etc.) to determine best combination of these substrates for maximum methane production rate.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.773-776
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• 2005

MSWI ash is the residue from waste combustion processes at temperature between $850^{\circ}C\;and\;1000^{\circ}C$. And the main components of MSWI ash are $SiO_2,\;CaO\;and\;Al_2O_3$. The aim of this study is to find a way to useful application of MSWI ash(after treatment) as a structural material and to investigates the hydraulic activity, compressive strength development, composition variation of such chemicallyi-activated MSWI ashes concrete. And it was found that early cement hydration, followed by the breakdown and dissolving of the MSWI-ashes, enhanced the formation of calcium silicate hydrates(C-S-H), The XRD and SEM-EDS results indicate that, both the hydration degree and strength development are closely connected with a curing condition and a chemically-activator. Compressive strengths with values in the 40.5MFa were obtained after curing the activated MSWI ashes with NaOH+water glass at $90^{\circ}C$.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.65-68
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• 1999

A plasma melting system to vitrify ny ash from MSW(Municipal Solid Waste) incinerator has been operated in SHI(Samsung Heavy Industries) since 1996. Waste feeding rate was 200kg/hr. with maximum working power of 500㎾. Because of high melting temperature of fly ash, bottom ash was used as an additive to decrease melting temperature. Data analysis for discharged slag shows volume reduction up to 30% and no leaching of heavy metals such as Pb, Cd, Cr which were an obstacle for landfill and recycle. Atmospheric pollution gas like nitrogen oxides, carbon monoxide, and PCDD/PCDF were restrained below the regulatory limit.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.172-179
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• 2003

Various type of tritium wastes can be produced from nuclear fuel cycle process satisfying non-proliferation, CANDU reactors, and nuclear industry. Activities of tritium processing in the world were surveyed to develope the processing technologies of tritium wastes. The tritium wastes were classified into gas phase, liquid phase, and organic phase. And the treatment techniques for the tritium wastes are analyzed. Development of tritium processing technologies is essential to finding public acceptance of radioactive wastes and forming a solid foundation to foster the growth of nuclear industry in Korea.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1660-1662
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• 1997

High temperature arc plasma technologies are recently being developed in Europe, Japan and United States as one or the treatment schemes of municipal wastes, industrial wastes and vitrification of low level radioactive wastes. An experimental plasma melting furnace, a transferred type plasma torch and 100kW class power supply have been made. Operation of this system and some basic experimental results for solid wastes treatment are reported.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.191-198
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• 2018

Improper management and unsanitary approaches are implemented in disposal of leachate, which has resulted in groundwater pollution at village Uruli Devachi, Pune, India. Various physico-chemical treatment methods are commercially available for leachate treatment. However, the application of biological methods viz. phytoremediation to the municipal solid waste landfill leachate has been limited. We report the remediation ability of Typha aungstifolia and Acrorus calamus that is capable of reducing hazardous constituents from the landfill leachate. After 96 h of hydraulic retention time (HRT), it was observed that T. aungstifolia-treated sample showed high reduction potential in reducing biochemical oxygen demand, chemical oxygen demand, hardness, total dissolved solids, Na, Mg, Ca and Ni whereas A. calamus showed greater reduction capacity for alkalinity, Cl, Cu, Zn and Cr. Furthermore, it was also observed that T. aungstifolia withstood longer HRT than A. calamus. In situ application of T. aungstifolia and A. calamus for remediation of landfill leachate carries a tremendous potential that needs to be further explored.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.108-115
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• 2012

Archaeological waterlogged woods found under the sea, in lakes, or in swamp environments are generally weak and fragile. If waterlogged wood materials were taken out of the water and left without modification, they would collapse and lose their original dimensions completely. Conservation is performed to replace the water with chemical agents and to give dimensional stabilization and durability. EDTA and PEG are the most commonly used in the preservation of wood. pH control-precipitation method is used for recovery of EDTA from waste fluid of archeological waterlogged wood conservation treatment. The black substance is eliminated from wood as Fe-EDTA complex are formed and EDTA is separated and precipitated from Fe-EDTA complexes at pH 2.68 or less. The result of analysis of the precipitated products and the commercial EDTA by FT-IR and FE-SEM showed that precipitated product by pH adjusted was not a type of Fe-EDTA complex, but pure EDTA. Waste fluid produced in PEG treatment shows the black color and has an offensive odor by organic matter extracted from wood. Color of waste fluid is decolored with oxidation reaction by peroxy hydrate. In FT-IR and SEM-EDX of PEG after freeze-drying process, no significant change of functional groups induced from oxidation is observed, and any metal ion does not exist in the solid PEG specimen. The molecular weight of PEG is measured using GPC and viscometry. Properties of PEG before and after preservation treatment, and after oxidation with $H_2O_2$ were not changed. Consequently, the peroxidation with $H_2O_2$ is a reasonable and simple method to decolor the used PEG solution.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.12
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• pp.1347-1351
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• 2006

It was tried to utilize organic waste sludge from wastewater treatment plant as a starting material to produce a solid fuel by vacuum flying. The effects of decompression levels, frying time and temperature on the calorific value and moisture of vacuum fried sludge were systematically investigated. Dewatered raw sludge used in this study had a moisture of 81.1% and calorific value of 2,930 kcal/kg. Based on the experimental observation, it was identified that the decompression level and frying time have the greatest influence on the calorific value of vacuum fried sludge. Moistures of the fried sludge at $180^{\circ}C$ for 25 min in 760 mmHg, 684 mmHg and 630 mmHg were 32.4%, 14.2% and 11.6%, respectively. Calorific values of the vacuum fried sludge at $140^{\circ}C$ for 15 min and 25 min were 5,400 kcal/kg and 5,540 kcal/kg in 684 mmHg and 5,520 kcal/kg and 5,660 kcal/kg in 630 mmHg, respectively.