• Tunnel and Underground Space
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• v.23 no.1
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• pp.13-30
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• 2013

Increase of pore fluid pressure resulting from injection of $CO_2$ may reactivate pre-existing faults, and the induced seismic activities can raise the safety issues such as seal integrity, restoration of storage capacity, and, in the worst case, removal of previously injected $CO_2$. Thus, fault stability and potential for $CO_2$ leakage need to be assessed at the stage of site selection and planning of injection pressure, based on the results of large-scale site investigations and numerical modeling for various scenarios. In this report, studies on the assessment of fault stability during injection of $CO_2$ were reviewed. The seismic activities associated with an artificial injection of fluids or a release of naturally trapped high-pressure fluids were first examined, and then site investigation methods for the magnitude and orientation of in situ stresses, the distribution and change of pore fluid pressure, and the location of faults were generally summarized. Recent research cases on possibility estimation of fault reactivation, prediction of seismic magnitude, and modeling of $CO_2$ leakage through a reactivated fault were presented.

• Journal of Environmental Impact Assessment
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• v.19 no.5
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• pp.475-481
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• 2010

Lots of pollutants typically originating from urban transportation are accumulating on the paved surfaces during dry periods and are washed-off directly to the river during a storm. Also, paved surfaces are contributing to increase in peak flows and volume of stormwater flows. These are the main reasons why the water quality of rivers and lakes remain polluted and still below standards. Currently, several management practices are being applied in developed countries but the design standards are still lacking. This research was conducted to develop a treatment technology that can be useful to address the problems concerning runoff quality and quantity. A lab scale infiltration device consisting of a pretreatment tank and media zone was designed and tested for various flow regimes characterizing the low, average and high intensity rainfall. Based on the experiments, the high intensity flow resulted to increase in outflow event mean concentration (EMC) of pollutants, about twice as much as the average outflow EMC. However, 78 to 88% of the total suspended solids were captured and retained in the pretreatment tank because of sedimentation. The removal of heavy metals such as zinc and lead was greatly affected by the vertical placement of woodchip layer prior to the media zone. It was observed that the high carbon content (almost 50%) in the woodchip provided opportunity for enhancing its uptake of metal by adsorption. The findings implied that the reduction of pollutants can be greatly achieved by means of proper pretreatment to allow for settling of particles with a combination of using high carbon source media like woodchip and a geotextile mat to reduce the flow before filtering into the media zone and finally discharging to the drainage system.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.247-255
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• 2016

Non-point pollutants from surface runoff during rainfall exert adverse effects on urban river water quality management. In particular, the first flush effect during the initial phase of rainfall can deliver significant amounts of pollutant loads to surface waters with extremely high concentrations. In this study, a sustainable first flush effect management system was developed by using settling and filtration that require no additional power or chemicals. A pilot scale experiment has shown that the removal of total suspended solid (TSS), total nitrogen (TN) and total phosphorus (TP) are in ranges of 84 - 95%, 31 - 46%, and 42 - 86%, respectively. An Integrated Stormwater Runoff Management System (ISTORMS) was also developed to efficiently manage the developed system by linking weather forecast, flow rate and water quality modeling of surface runoff and automatic monitoring systems in fields and in the system. This study can provide effective solutions for the management of urban river in terms of both quantity and quality.

• Journal of Animal Environmental Science
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• v.18 no.1
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• pp.25-34
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• 2012

Noxious gases with malodorous substance concentrations in each stages of pig buildings were determined at a typical 400sow-scale farm to improve piggery environment. Using IAQ-300 and pDR-1000AN, continuous records for the concentration of $NH_3$, CO, $CO_2$, $NO_2$, $SO_2$, $H_2S$, $O_2$, and along with temperature, humidity, dust concentrates from individual pig pens were collected to analyze every 6 hours' condition of indoor environment for 24 hours' period. In most pig houses, the air quality at noon was good, while at night (00:00~06:00), air composition became noxious in all buildings. The order of buildings' air quality for 24 hrs was pregnant > farrowing > nursery > growing > finishing. The cause of air quality differences was presumed to be the differences of stocking density, defecating amount and the length of exposure time of slurry in indoors. In conclusion, well-designed building structure, proper control of stocking density, quick removal of excreta from pig pens and continuous ventilation are prerequisites to improve pig housing environment.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.259-270
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• 2017

In this study, field-scale half-saturated bio-filter wetland equipped with recirculation system was operated with stormwater from the paved road, and its operational performance and functions of LID-BMP were analyzed and compared with other facilities. The reduction of TSS, COD, TN, and TP were 92%, 63%, 36%, and 75%, respectively. Comparison of the reduction efficiency were carried out with respect to ratio between surface and catchment areas(SA/CA). In addition, this LID-BMP facility can reduce about 70% of pollutant by treating only 18% of total rainfall runoff. The results show that LID used for this study gave similar efficiency although its ratio was smaller. In addition, comparison study was made between synthetic fiber as a filter media and organic media, which shows that there was not any significant difference between, TSS and TP reduction, but there were large difference in COD and TN removal due to the presence and absence of release of organic carbon. Meanwhile, wetland system in this study equipped with a first-flush capture gave a higher stability in terms of treatment performance.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.7 no.1
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• pp.5-14
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• 2000

This study was conducted during the time period of September 1997 to February 1999. in order to provide data concerning important facets of horne care nursing and the degree to which practicing hospital and public health nurses believe themselves to be competent in each area. The study subjects consisted of 610 hospital nurses, 158 public health nurses and 21 other nurses from Seoul and the province of Kyunggi. Korea. Data was collected through self-reporting questionnaires which was used by Kim et al.(1999) to evaluate the status of home health nursing and the varying ideas of self-competence that practicing nurses have. The results of the study were as follows: 1) The mean scores of perceived important components and competencies on home health nursing measured on the Likert 4 point scale were $3.15{\pm}0.36$ for importance. and $2.56{\pm}0.36$ for competency. Of the four categories regarding nursing services, the 'Nursing skill' factor had the highest importance and competency. 2) There were significantly higher scores for hospital nurses' importance components and competencies of home care nursing as compared to those scores for public health nurses. 3) The significant factors of the importance component of home care nursing listed in order of priority were 'general infection control', 'bed sore care skill', 'rehabilitation care', 'keeping maintenance of the client's confidentiality', 'malpractice', 'diabetes patient care', 'ability for problem solving' respectively. In contrast, of low priority in the importance components of home care nursing were 'referring nursing as a job to others'. 'record keeping', 'family dynamics', 'medical equipment', 'economic problems', 'environmental assessment', 'suture removal', 'multidisciplinary coordination' respectively. 4) The high priority of the degree to which practicing nurses believe themselves to be competent in home health nursing were the 'blood sugar test', 'enema skill', 'injection skill', 'skin care', 'bed sore care skill', etc. In contrast, lower competence for home care nursing as perceived by nurses were 'AIDS care', 'family violence care', 'substance abuse care', 'mental health care' respectively.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.471-480
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• 2006

The field scale experiment was performed to examine the performance of the constructed wetland for nonpoint source (NPS) pollution loading reduction. Four sets (each set of 0.88 ha) of wetland (0.8 ha) and pond (0.08 ha) systems were used. Water flowing into the Seokmoon estuarine reservoir from the Dangjin stream was pumped into wetland systems. Water depth was maintained at 0.3-0.5 m and hydraulic retention time was managed to about 2-5 days; emergent plants were allowed to grow in the wetland. The wetland effluent concentrations of $BOD_5$, TSS, and T-N were higher in winter than in the growing season excepting the T-P, and effluent $BOD_5$ concentration was higher than influents in winter. Mass retention of T-N and T-P was stable throughout the year, whereas mass retention of $BOD_5$ and TSS was decreased in winter. $BOD_5$, TSS, T-N, and T-P performance of the experi-mental system was compared with the existing database (North American Treatment Wetland Database), and was within the range of general system performance. From the first-order analysis, T-P was virtually not temperature dependent, and $BOD_5$ and TSS were more temperature dependent than T-N. Overall, the wetland system was found to be an adequate alternative for treating polluted stream water with stable removal efficiency and recommended as a NPS control measures.

• Clean Technology
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• v.26 no.2
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• pp.96-101
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• 2020

In this paper, the commercial feasibility of trigeneration, producing heat, power, and hydrogen (CHHP) and using biogas derived from macroalgae (i.e., seaweed biomass feedstock), are investigated. For this purpose, a commercial scale trigeneration process, consisting of three MW solid oxide fuel cells (SOFCs), gas turbine, and organic Rankine cycle, is designed conceptually and simulated using Aspen plus, a commercial process simulator. To produce hydrogen, a solid oxide fuel cell system is re-designed by the removal of after-burner and the addition of a water-gas shift reactor. The cost of each unit operation equipment in the process is estimated through the calculated heat and mass balances from simulation, with the techno-economic analysis following through. The designed CHHP process produces 2.3 MW of net power and 50 kg hr^-1 of hydrogen with an efficiency of 37% using 2 ton hr^-1 of biogas from 3.47 ton hr^-1 (dry basis) of brown algae as feedstock. Based on these results, a realistic scenario is evaluated economically and the breakeven electricity selling price (BESP) is calculated. The calculated BESP is ¢10.45 kWh^-1, which is comparable to or better than the conventional power generation. This means that the CHHP process based on SOFC can be a viable alternative when the technical targets on SOFC are reached.

• Korean Journal of Microbiology
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• v.36 no.4
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• pp.279-284
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• 2000

Simultaneous reduction of Cr(VI) and degradation of phenol was observed in batch and bench-scale continuous stirred tank reactors using Rhodococcus sp. CP01 isolated from leachate. The strain CP01, which was capable of utilizing phenol as a sole source of carbon and energy, completely reduced added hexavalent chromium (0.25 mM) to its trivalent form during 60 hr batch assay under optimal conditions (pH 7.0 and 1,000 mg/L of phenol concentration). The rates of Cr(VI) reduction and phenol degradation were estimated as 4.17 $\mu$M Cr(VI) and 38.4 mg phenol.$L^{-1}{\cdot}hr^{-1}$, respectively. The continuous culture experiment was conducted for 46 days using synthetic feed containing different levels of chromate (0.0625 to 0.25 mM) and phenol(1,000 to 4,000 mg/L). With a hydraulic retention time of 100 hr, Cr(VI) reduction efficiency was mostly 100% for influent Cr(VI) and phenol concentrations of 0.125 mM and 3,000 mg/L, respectively. During quasi-steady-state operation, specific rate of Cr(VI) reduction was calculated as 0.34 mg Cr(VI).g $protein^{-1}{\cdot}hr^{-1}$ which was comparable to reported values obtained by using glucose as growth substrate. The results suggest the potential application of biological treatment for detoxification of wastewater contaminated simultaneously with Cr(VI) and pheonol.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.23-32
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• 2014

Recently, it is increase in the processing of organic waste using anaerobic digestion. Therefore, the studies on the processing method for increasing the anaerobic digestion waste water. But it is very difficult to solid-liquid separation, because the characteristics of anaerobic digestion waste water. So this study evaluate solid-liquid separation efficiency of anaerobic digestion sludge using CST(Capillary Suction Time), TTF(Time to Filter). To address this problem, a membrane filter press of the lab scale was produced and the anaerobic digestion wastewater was applied to it. Polymer coagulants were found to be most suitable 7192PLUS and 1T60, It is necessary to minimum injection concentration is 7192PLUS (200 mg/L), 1T60 (100 mg/L). To evaluate dehydration efficiency, it was measured the moisture content of the dehydrated cake and suspended solids of decanted water. As a result, showed that a high removal efficiency of 97.4% when the solid-liquid separation using the membrane filter press. And the moisture content of the dehydrated cake was less than 65%.