• Journal of Soil and Groundwater Environment
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• v.15 no.4
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• pp.21-29
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• 2010

As the target area of this study, the coal mine site of Dongwon Sabuk mine.,ltd. is located in the remote mountainous region. To purify the acid mine water contaminated with heavy metals, a pilot-scale plant was built at the surrounded area of a mine shaft and operated to simulate active treatment system that could not only possibly setup the facility in a small available area, but also has a high efficiency. According to the various conditions of basin sequence, existence of sludge return, and lime injection position, six different types of treatment series were investigated in terms of treatment efficiency. As a result, the aluminum concentrations of the most effluents were in the range of 0.005~0.030 mg/L, which was too low to compare. The manganese concentration in the treated water were in the range of 3~9 mg/L, not following any regular trend. As found in the results of iron concentration, the case of addition of oxidation and sludge return steps showed higher efficiency than the others. As a standpoint of the installation of full-scale physicochemical treatment facility, the experimental results showed that the batch of oxidation and high density sludge return processes are existed and neutralization was followed by oxidation, had a stable treatment efficiency.

• Economic and Environmental Geology
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• v.28 no.5
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• pp.469-480
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• 1995

Gravity and magnetic surveys were carried out to investigate the three-dimensional configuration and characteristics of the landfills at Nanjido waste disposal site. For terrain correction and three-dimensional density inversion of gravity data an algorithm, which calculates the gravity effect of a three-dimensional body by using the solid angle method, is developed. This algorithm has been proved to give more accurate terrain correction values for the small survey area having varied topography like Nanjido site as compared with widely used methods such as Hammer's method and multiquadric equation method. Density inversion of gravity anomaly data gives very useful information about the lateral and vertical variation of the landfills, which can be used to discriminate the kinds of wastes. The average density of filled materials appears to be $1.7\;g/cm^3$ which is much higher than the value $(0.8\;g/cm^3)$ estimated by Seoul City. The lateral variation of density shows high correlation with the pattern of ongoing depression of the landfills. The northern region of the landfill no. 1, which shows low density and high depression, is closely associated with the industrial waste and sludge filled area. The magnetic anomaly data provide information about relative concentration of magnetic materials, which is also very useful to investigate characteristics of the fills. Several high positive anomaly regions on the reduced-to-pole magnetic anomaly map are appeared to be associated with the industrial waste fills, but certain industrial waste fills show low negative anomalies. This kind of magnetic information can be used in selecting drilling locations over landfills away from buried metal products during the stabilization process.

• Journal of Korean Society on Water Environment
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• v.16 no.4
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• pp.523-532
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• 2000

The purpose of this study was to investigate the effects of the hydraulic retention time (HRT) and organic loading rate (OLR) on microbial characteristics and treatment efficiency in sewage treatment using aerated submerged biological filter (ASBF) reactor. This reactor combines biodegradation of organic substrates by fixed biomass with a physical separation of biomass by filtration in a single reactor. Both simulated wastewater and domestic wastewater were used as feed solutions. The experimental conditions were a temperature of 17 to $27^{\circ}C$, a hydraulic retention time of 1 to 9hr, an organic loading rate of 0.47 to $3.84kg\;BOD/m^3{\cdot}day$ in ASBF reactor. This equipment could obtain a stable effluent quality in spite of high variation of influent loading rate. Total biomass concentration. biofilm thickness and biofilm mass increased an exponential function according to the increasing OLR. The relationships between water content and biofilm density were in inverse proportion. The percentage of backwash water to influent flow was almost 9%. The separation efficiency of biomass was the percentage of 91 to 92 in ASBF reactor. The sludge production rates in feed solutions of simulated wastewater and domestic wastewater were 0.14~0.26 kg VSS/kg BODrem, 0.43~0.48 kg VSS/kg BODrem, respectively.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.62-69
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• 1998

It has been studied that the measurement of odor component emission at confectionery manufacture. The objects of this study were to investigate reduction of offensive odor. The survey effects of odorous materials are presented as follows. The countermeasure of operating process is to minimize sludge sediment in each unit facility. Especially, in summer, we have to clean the sludge frequently, because anaerobic decomposing is likely to occur easily. The sludge or scum from sedimentation tank pond, and floating tank should be treated quickly. We should avoid overloading operation. In the case of overloading, dissolved oxygen should be increased, the quality of wastewater input should be decreased. When dried cakes from condense tank or floating tank are left in treatment plant, we should cover, to prevent diffusion of smell with masking materials. The seasonal condition of operating should be fixed and the kind of coagulants should be changed because the wastewater in each season have different loading rates and organic materials. Odorous materials are very sensitive to the seasonal temperature variation. Especially, when the amount of rainfall is small and the high temperature of maintenance in long periods, air diffusion rate is large, so odorous materials can make great effect on surroundings comparision with other periods. To reduce odorous gas, as short term method, we had better take ceramic addition method. Especially, in summer we should take ceramic addition method. Also, as long term method, the size of wastewater treatment facility is the most important in the normal operating of wastewater treatment facility. But wastewater treatment facilities in this factory are too old, treatment process is old fashion, and the size is too small. So, large wastewater quantity to treat in summer. As results, the expansion of wastewater treatment facility and the process of improvement are required. Restriction level of odor was exceed. As it is overloaded in summer, the basis cause of odor is that the size of wastewater treatment facility is small. The prediction of air quality equilibrium density variation show that the odorous materials from working place are Amine materials whose smell strength is about 2.5(a little strong degree). We can suppose that in summer is sensitive to temperature variation, smell strength is larger as to reduce the origin of odor. We must expand wastewater treatment facility and improve the process A.S.A.P.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.273-278
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• 2003

The effects of content and particle size of sewage sludge slag on the sound absorption was investigated and the physical$.$mechanical properties of porous ceramics for sound absorbent material was studied. The physical$.$mechanical properties of specimens have depended on sintering temperature and slag content without particle size effect of slag. As water glass content increase and particle size of slag decrease at the same slag content, physical$.$mechanical properties of them have been improved. The bulk density and compressive strength of specimens with the batch composition of 77∼89 wt% of slag content and particles with 1∼3 mm, and sintered at 1,050$^{\circ}C$ for 2 h were 1.48∼1.71 and 86∼163 kgf/$\textrm{cm}^2$, respectively. The specimens with 1∼3 mm and <1 mm of particles size showed good sound absorption property at low frequency and high frequency region. With increasing thickness of specimens, sound absorption properties at low frequency region were increased.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.41-48
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• 2000

In this study, we have investigated the effect of the various operating conditions on the removal fluorine in the rinsed water for the semiconductor industry by using electrolysis process. The removal efficiency of fluorine was irrelevant to initial pH, and carbon anode was high-level treatment in the effect of various electrodes. Fluorine included in the wastewater is treated by the addition of a Ca(OH)2, removal efficiency of electrolysis was increased about 40%. Besides the removal efficiency of fluorine was increased as the current density was increased and this treatment system could reduce both the total sludge and running costs. The feasibility of the electrochemical treatment to the fluorine containing wastewater was verified from this study.

• Journal of the Korean Ceramic Society
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• v.35 no.6
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• pp.575-582
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• 1998

Sutiability of Jungsan clay shale dolomite sludge Anyang feldspar and alumina as raw materials for light-weight porous ceramics was examined. In order to find optimum manufacturing conditions compositions heating temperatuers and heating times were varied and their effects on physical properties were measured and bloating mechanism was investigated. Jungsan clay seems suitable as raw material to make the light-weight constructional materials with 5wt% of ANyang feldspar and alumina added in calcined clay (800$^{\circ}C$) having bulk density of 0.45g/cm3 water absorption of 1.34% and compressive strength of 85kg/cm2 rapid-heated at 1200$^{\circ}C$ for 30min. It is suggested that bloating mechanism depends on the difference of tem-peratures between the inside and outside in specimen the remained gases in interstices can bloat by the li-quid phase of surface with high viscosity and gas pressure at elevated temperature.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.210-215
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• 2004

Porous ceramics for water-permeable paving brick was prepared by the sintering of mixed materials comprising of sewage sludge ash, waste porcelain fragment, waste glaze and low-grade clay at 1,000$^{\circ}C$ for 2 h, and the physical $.$mechanical properties, the permeability and the freeze-thaw resistance of specimens with preparation parameters were investigated. The physical mechanical properties were increased in specimens while porosity and permeability were decreased with increasing sewage sludge ash content and sintering temperature on the properties of specimens showed the opposite results. The bulk density, porosity, compressive strength and permeability (passed charge) of 30A60F specimens with 30 wt% of sewage sludge ash content, waste porcelain fragment size with 1∼2 mm and sintered at 1,000$^{\circ}C$ for 2 h were 2.17, 46.2%, 221 kgf/$\textrm{cm}^2$ and 3,150 coulombs, respectively. The permeability was increased with increasing waste porcelain fragment size, however compressive strength was decreased. The freeze-thaw resistance of 30A60F specimen with 1∼2 mm of fragment size was superior to that of the other specimens. The 30A60F specimens can be used for the water-permeable paving brick with the high permeability and adequate strength. The heavy metals included in the all specimens showed lower than the standard level.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.4
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• pp.174-181
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• 2021

Lightweight geopolymers were fabricated by using IGCC (integrated gasification combined cycle) slag and Si sludge which are classified as general wastes (recyclable resources). Three curing methods were tried to investigate the changes in compressive strength and density according to the curing method and immersion time. Immersion period was tried up to 21 days to observe long-term performance in water. Compressive strength of the specimens cured in oven decreased abruptly with an increase in immersion time. Compressive strength of the specimen cured in autoclave was low after 3 and 7 day immersion; however, increased rapidly after 21 day immersion. On the contrary, compressive strength of the specimen cured in autoclave and oven was high but substantially decreased after 21 day immersion. Conclusively, it was speculated that oven curing is effective for the compressive strength development at early age; however, autoclave curing is more desirable for the long-term performance in water.

• Journal of Wellbeing Management and Applied Psychology
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• v.4 no.2
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• pp.19-25
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• 2021

Purpose: The purpose of this study is to reduce odor complaints by identifying problems with odor management at the site of the water regeneration center and researching odor management methods. Due to the high population density of Korea, sewage treatment facilities are adjacent to residential and industrial areas. According to previous studies, the main malodor-emitting facilities of sewage treatment facilities were preliminary treatment facilities (2,220 times), sedimentation basins (4,628 times), and sludge treatment facilities (9,616 times). Research design, data and methodology: Compound malodors and designated malodor-producing substances were collected from five site boundaries of the water regeneration center and analyzed according to the official methods to test malodor, and a total of two times (August and September 2020) were conducted. Results: As a result of the measurement, in the green area in front of the center office, compound malodors were detected at a maximum of 8 times and at least 3 times during the dawn time. As for the designated malodor-producing substances, 0.1ppm of ammonia was detected in the green area in front of the center office and the park golf course. This is within 15 times the maximum allowable emission level of compound malodors and within 1ppm of the maximum allowable emission level of ammonia. Conclusions: Even if the dilution rate of the compound malodors did not exceed the maximum allowable emission level, the odor could be recognized, and more research is needed in the future to establish effective reduction measures according to the subjective and individual and seasonal odor characteristics.