• Journal of Radiation Industry
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• v.2 no.1
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• pp.21-26
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• 2008

Although seafood cooking drips were the byproducts from the fishery industry it was known that the cooking drips had many nutrients and could be used as functional materials. Previously, the physiological properties of cooking drips were shown to be increased by a gamma irradiation. But, there was no report on the safe for the genotoxicity on the irradiation. In this study, the genotoxicity of the cooking drips from Hizikia fusiformis, Enteroctopus dofleni and Thunnus thynnus was evaluated by the Ames test (Salmonella typhimurium reversion assay) and the SOS chromotest. The results from all samples were negative in the bacterial reversion assay with S. typhimurium TA98, TA100. No mutagenicity was detected in the assay, both with and without metabolic activation. The SOS chromotest also indicated that the gamma-irradiated seafood cooking drips did not show any mutagenicity. Therefore, this study indicated that gamma irradiation could be used for the hygiene, functional properties and processibility of seafood cooking drips.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.107-115
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• 2019

The many countries are facing the shortage of natural resources, and the supply of aggregates are being exhausted. To consider this situation a variety of studies were performed for the development of alternative resources. In particular, high density filler material was used for shielding radioactive waste, large amount of natural aggregates are required in order to produce filler material. Also, in order to improve the shielding performance of filler material, it is required to increase the density of the filler material. Therefore, in this study was carried out to provide basic data for expanding the feasibility of high density industrial waste resource as aggregate in heavyweight concrete. From the test results, OPC case, concrete strength decreased by using heavyweight waste glass as fine aggregate, however, it is improved by using mineral admixture as binder. Therefore, when the heavyweight waste glass and steel slag are applied to heavyweight concrete, it is desirable to use mineral admixture, especially to use BFS than FA. Meanwhile, when the steel slag was replaced as coarse aggregate of heavyweight concrete, elasticity of modulus and radiation shielding performance can be improved owing to high density of steel slag.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.56-64
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• 2019

Various approaches have been attempted to develop recycling technologies related to industrial waste resources containing metals. Among them, glass is not decomposed into microorganisms, so landfill is not suitable, and interest in the recycling of waste glass is increasing. In this paper, by incorporating chelate resin to suppress the elution of heavy metals in waste glass and using waste glass as a fine aggregate and we want to evaluate the strength, drying shrinkage, alkali-silica reaction and heavy metal leaching of shielded filler materials and to provide basic data for utilizing waste glass as an economical and environmentally friendly shielding filler. As a result of the test, it was found that the use of waste glass as a fine aggregate was effective in the development of strength, but the incorporation of chelate resin had an influence on the strength development. In addition, the addition of chelate resin was effective in improving drying shrinkage but it was found to affect the alkali - silica reaction. As a result of the heavy metal leaching test, the KSLP test method satisfies all the criteria for heavy metal leaching. However, in case of lead, the limit of US ANSI 67-2007a was exceeded and further study should be done.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.112-121
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• 2009

To obtain basic design criteria for underground anaerobic digestion and enhance biogas production from swine slurry, a $20m^3$ underground anaerobic digester (UGAD) was constructed and operated at mesophilic ($31{\sim}37^{\circ}C$) temperature with an organic loading rate (OLR) at $23.6kgVS/m^3/day$. The average biogas and $CH_4$ production rate were observed at 8.62 and $5.78m^3/day$, respectively. The mean percentile of $CH_4$ and $CO_2$ were also observed at 67.5% and 19.6%. The relative biogas yield was explored at $733L/kg\;VS_{added}$ and $CH_4$ yield was at $495L/kg\;VS_{added}$ respectively. The removal rate of biochemical constituents and pathogens were noticed considerably at 68%, 74%, 79%, 86%, 89%, 81%, 55%, 79%, 98% and 100% on TS, VS, TSS, $BOD_5$, $TCOD_{cr}$, $SCOD_{cr}$, $NH_3-N$, available P, fecal coliforms and Salmonella, respectively. This study suggested that, the modified UGAD system is a greatly desirable for anaerobic digestion for swine slurry with regards to high methane yield and biodegradability.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.147-158
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• 2008

In this study, fermentation characteristics of waste agricultural and forest biomass for production of heat energy were focused to be used in agricultural farm households. The purpose of this study was focused on seeking practical utilization of agricultural and forest biomass wastes in agricultural farm households in the form of thermal energy by means of simple fermentation process. Fermentation process was performed in terms of different raw-materials and their mixture with different ratios. Urea, lime, and bioaids were added as fermenting aids. Moisture contents of fermenting substrates were adjusted to 55~65%. In order to optimize the fermentation process various factors, such as raw-materials, moisture contents, amount of fermenting aids, and practical measurement of hot-water temperature during fermentation were carefully investigated. The optimum condition of fermenting process were obtained from hardwood only and hardwood: softwood (50 : 50) beds. In case of hardwood only the highest temperature was recorded between 60 to $90^{\circ}C$ the lowest temperature was determined to more or less $40^{\circ}C$ and the average temperature was ranged to $50{\sim}60^{\circ}C$ and this temperature ranges were maintained up to 20~30 days. The optimum amount of additives were estimated to ca. 15 kg of urea, 20 kg of bioaids, and 10 kg of lime for 1 ton of substrate. To reach the highest temperature the optimum moisture content of fermenting substrate was proved to 55% among three moisture content treatments of 45%, 55% and 65%. The temperature of hot-water tank installed in fermenting bed of hardwood : grass (50 : 50) showed very different patterns according to measuring positions. In general, temperatures in the mid- and upper-parts of substrate piling were relative higher than lower and surface parts during 45-day fermentation process. The maximum temperature of fermenting stage was determined to $65^{\circ}C$, minimum temperature, more or less $40^{\circ}C$, and average temperature was $60^{\circ}C$. The water temperature of tank exit was ranged to $33{\sim}48^{\circ}C$ during whole measuring periods. It could be concluded that fermentation process of waste agricultural and forest biomass produces a considerable amounts of heat, averaging about $50{\sim}60^{\circ}C$ for maximum 3 months by using the heat exchanger (HX-helical type).

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1116-1122
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• 2008

The existing technology which is for recycling aggregate using dried swage sludge have been limited for practical application, because the properties of aggregate are not regular and don't meet the recycling aggregate standard. In this research, an innovative slag-producing technology is developed by addition of oyster shell, waste cast-sand and iron-rust as inorganic waste additives. The mixed slag with the additives was evaluated at the various ratio of CaO/SiO$_2$, SiO$_2$/Al$_2$O$_3$ and Fe$_2$O$_3$/SiO$_2$. When the waste sludge was melted at 1,400$^{\circ}C$ during 20 minutes, the optimal ratio of CaO/SiO$_2$ for the slag added the oyster shell, SiO$_2$/Al$_2$O$_3$ for added the waste cast-sand and Fe$_2$O$_3$/SiO$_2$ for added the iron-rust were 1.00, 3.00 and 0.60, respectively. At the optimal condition, the bulk density of the slag was 2.24 g/cm$^3$, 2.45 g/cm$^3$ and 2.73 g/cm$^3$, And the 24 h water adsorption was 4.72%, 1.44% and 0.37%, respectively. Therefore it is proved that adding the waste additives to the process of the slag production contributed for elevation of recycling aggregate properties. And also it is expected that production cost can be reduced by decreased melting temperature.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.694-699
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• 2008

Considering the severe regulation associated with sludge treatment such as direct landfill and ocean dumping, there is no doubt in that an advanced study for the proper treatment of sludge is urgently needed in near feature. As one of viable method for sludge treatment, fry-drying of sludge by waste oil has been investigated in this study. The fundamental mechanism of this drying method lies in the phenomenon of rapid moisture escape in the sludge pore toward oil media. This is caused by the severe pressure gradient formed by the rapid oil heating between sludge and oil. As part of research effort of fry-drying using waste oil, a series of basic study has been made experimentally to obtain typical drying curves as function of important parameters such as drying temperature, drying time, oil type and geometrical shape of sludge formed. Based on this study, a number of useful conclusion can be drawn as following. The fry-drying method by oil immersion was found quite effective in the removal efficiency of sludge moisture, in general, the moisture content decreases significantly after 10 minutes and the whole moisture content was less than 5% after 14 minutes regardless of the drying temperature. The increase of oil temperature up to 140$^{\circ}C$ favors significantly for the removal of moisture but there was no visible difference above 140$^{\circ}C$. As expected, the decrease of diameter in sludge was efficient in drying due to the increased surface area per unit volume. Further, the effect of oil property by the change of oil type was noted. To be specific, for the case of engine oil the efficiency was found to be remarkably delayed in moisture evaporation compared with that of vegetable oil due to the increased viscosity of engine oil. It produced a result of increasing the evaporation of moisture largely relatively high in the drying temperature over 140$^{\circ}C$ compared with the drying temperature 120$^{\circ}C$ drying temperature as the drying time passed. Accordingly, the drying temperature is considered desirable as keeping over 140$^{\circ}C$ regardless of a sort of used oil.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.240-246
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• 2014

A semi-pilot biofilter inoculated with the microbes consortium of Bacillus cereus DAH-1056 and Arthrobacter sp. KDE-0311 was operated under various operating conditions in order to treat malodorous waste air containing both hydrogen sulfide and ammonia. When both hydrogen sulfide and ammonia contained in malodorous waste air were treated simultaneously by semi-pilot biofilter inoculated with Thiobacillus sp. IW and return-sludge, the removal efficiencies of hydrogen sulfide and ammonia were ca. 80% and ca. 50%, respectively. On the other hand, in this study, the removal efficiencies of hydrogen sulfide and ammonia were ca. 90% and ca. 60%, respectively. Therefore, the removal efficiencies of hydrogen sulfide and ammonia were enhanced by ca. 13% and 20%, respectively, compared to the semipilot biofilter inoculated with Thiobacillus sp. IW and return-sludge. In addition, in this study, the maximum elimination capacities of hydrogen sulfide and ammonia were enhanced by ca. 15% ($8g/m^3/h$) and 10~17% ($3{\sim}5g/m^3/h$), respectively. In this study, it was observed either that in case of even a same inlet load of hydrogen sulfide, a higher concentration of hydrogen sulfide causes more difficulties in treating ammonia containing in waste air than a lower one, or that in case of even a same inlet load of ammonia, a lower concentration of ammonia results in higher removal efficienciy and elimination capacity than a higher one. Even though hydrogen sulfide and ammonia were treated simultaneously by a biofilter in this study, the maximum elimination capacity of hydrogen sulfide in this study exceeded or was similar to that in previous study of biofilter treating only hydrogen sulfide. In addition, this study showed the higher maximum elimination capacity of ammonia than other previous investigation of biofilter treating hydrogen sulfide and ammonia simultaneously.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.94-104
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• 2009

It is urgently required to develop the production of fermentation-heat energy from the waste agricultural and forest biomass and its effective heat exchanging system for the supply of warm water to rural households and greenhouses. In this study 3 helical-type and 1 plate-type heat exchangers using 3 different waste biomasses [e.g. hardwood (HW) sawdust (100%), softwood (SW) sawdust : HW sawdust (50 : 50) and HW sawdust : grass (90 : 10)] were applied in order to find out the best heat recovery system. The heat exchanger was basically considered to improve the overall heat recovery efficiency, to minimize heat loss and to simplify manufacturing, assembling and breaking up the fermenting beds. The helical-type heat exchanger (HX-H3) installed in fermenting bed of HW sawdust : grass (90 : 10) showed relatively higher temperature profiles, in particular mid- and upper-parts than lower and surface parts during 45-day fermentation process. The maximum temperature was ranged from $40^{\circ}C$ to $65^{\circ}C$ with average $60^{\circ}C$. The water temperature of tank outlet was ranged to $33{\sim}48^{\circ}C$ during whole measuring periods. By the way plate-type one (HX-P) installed in same biomass compositional fermenting bed showed $64.5{\sim}76.5^{\circ}C$ at center part, and $43{\sim}56^{\circ}C$ and $42{\sim}58^{\circ}C$, water tank and tank outlet temperatures, respectively, during 100 day measurement. It could be concluded that the plate-type heat exchanger (HX-P) provides not only the effective heating for the rural households and greenhouses, but also having the best heat recovery performance, easy manufacturing, assembling and breaking up the systems.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.549-557
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• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.