• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1477-1485
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• 2018

There are two major issues for activated sludge process in sewage treatment plant. One is how to make sewage be more clean and the other is the energy saving in sewage treatment process. The major monitoring sewage qualities are chemical oxygen demand, phosphorus, nitrogen, suspended solid in effluent. These are transmitted to the national TMS(Telemetry Monitoring System) at every hour. If these exceed the environmental standard, the environmental charges imposed. So, these water qualities are to be controlled below the environmental standard in operation of sewage treatment plant. And recently, the energy saving is also important in process operation. Over 50% energy is consumed in blowers and motors for injection oxygen into aeration tank. So, with the water qualities to be controlled below the environmental standard, the energy saving also is to be accomplished for efficient plant management. Almost researches are aimed to control water quality without considering energy saving. AI techniques have been used for control water quality. AI modeling simulator provided the optimal control inputs(blower speed, waste sludge, return sludge) for control water quality. Blower speed is the main control input for activated sludge process. To make sewage be more clean, the excessive blower speed is supplied, but water quality is not better than the previous. In results, non necessary energy is consumed. In this paper we propose a new method that the energy saving also is to be accomplished with the water qualities to be controlled below the environmental standard for efficient plant management. Water qualities in only aeration tank are used the inputs of fuzzy models. Outputs of these models are chemical oxygen demand, phosphorus, nitrogen, suspended solid in effluent and have the environmental standards. In test, we found this method could save 10% energy than the previous methods.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.3
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• pp.58-66
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• 2006

Environmental Sensitivity Index Map(ESI Map) is useful information for efficient and prompt contolling of oil spill accident. Environmental sensitivity information relating to oil spill is very various, so efficient access and utilization for environmental sensitivity information at control field is required. In order to improve the efficiency of controlling accident at the field, it is necessary to building digital ESI Map and GIS program. In this study, GIS database was built to utilize environmental sensitivity information at Yeosu and Gyunggi bay. And the ESI Map program which is focused on the control job was developed. IMO/IPIECA's guide to make the ESI Map and Korea Coast Guard's guide to collect information for the control information map were referenced to capture environmental sensitivity data and build GIS database. The symbology of environmental sensitivity layers was defined and functions for supporting control job were implemented in ESI Map program. For the future works, the program in this study could be applied to ESI Map program for the whole coastal area of Korea and it could be the essential element technology in marine pollution control supporting system.

• Development and Reproduction
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• v.17 no.1
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• pp.37-43
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• 2013

Cynomorium songaricum (CS) has been used in traditional Korean medicine in treating male impotence and sexual dysfunction. We investigated the effects of aqueous CS extract on the reproductive activity of golden hamsters whose spermatogenetic capacity is active in summer and inactive in winter. The animals were divided into 5 groups: long photoperiod (LP) control, short photoperiod (SP) control, and SP animals treated with low, middle, or high concentrations of CS. The animals were orally ingested with low (0.5 g/kg), middle (1.0 g/kg), or high (2.5 g/kg) concentrations of the aqueous extracts for 8 weeks on the daily basis. The control animals received the vehicle. As results, the LP control animals showed active testicular function but SP control animals displayed remarkably reduced testicular weights. The outcomes of the reproductive activity from low and middle concentrations of CS treatments were identical and marked as low dose. The consequences were a partial blocking of regressing activity by SP. On the other hand, the animals treated with high dose of CS extract showed remarkable significance in comparison to the SP control, indicative of a complete blocking effect of the CS on the regressing testes by SP. There were a dose-dependent effects of the CS on the sexual function. These results suggest that the CS extract promotes the male fertility by strengthening the spermatogenesis in the golden hamsters.

• Environmental Engineering Research
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• v.16 no.2
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• pp.103-109
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• 2011

This work experimentally determined the effect of thermal and microwave pretreatments on the anaerobic digestion of mixtures of municipal primary and secondary sludges in semi-continuous mesophilic digesters at hydraulic retention times (HRT) of 20, 15, 10, 7, and 5 days. The ratio of soluble chemical oxygen demand (COD) to total COD in thermally pretreated and microwaved sludges at $80^{\circ}C$ was 2.7 and 3.2 times higher than that of raw sludge, respectively. The volatile solids (VS) and COD removal efficiencies in all three digesters fed with raw (control), thermally pretreated (TM), and microwaved (MW) sludges decreased as the HRT was reduced. The highest relative improvement in VS removal compared to the control occurred at the HRT of 5 days in the TM and MW (29 and 41% higher than the control, respectively). At this HRT, improvement in the COD removal efficiencies in the TM and MW compared to the control was 28 and 53%, respectively. Improvements in biogas production compared with the control increased in both the TM and MW as the HRT was reduced to 5 days. The relative improvement in daily biogas production compared to the control from the TM and MW was 33 and 53% higher than the control at the HRT of 5 days, respectively. The results show that microwave pretreatment is more effective than thermal pretreatment in increasing the solubilization degree and mesophilic anaerobic biodegradability of sewage sludge.

• Proceedings of the Microbiological Society of Korea Conference
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• 2009.05a
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• pp.96-96
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• 2009

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1996.12a
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• pp.62-62
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• 1996

• Journal of Environmental Science International
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• v.13 no.4
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• pp.339-347
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• 2004

This paper asks the question: what choice of environmental policy instruments is efficient to reduce sulfur dioxide from stationary sources\ulcorner: In Korea, command and control has been a common way of controlling $SO_2-emissions.$ When compared to the non-incentive environmental policy instrument such as command and control, economic incentive environmental policy instrument has been the advantage of making polluter himself flexibly deals with in marginal abatement cost to develop environmental technology in the long view. Therefore, the application possibility of the incentive environmental policy instrument was studied in this research to realize the countermeasure for controlling of $SO_2-emissions.$ As a result, enforcement of the countermeasure such as flue gas desulfurizer by command and control would be suitable because power generation is performed by the public or for the public in source of air pollution and thus, economic principle is not applied to the polluter. In the source of industrial pollution, enforcement of fuel tax is found to be suitable for the countermeasure for the use of low sulfur oil in terms of the flexibility of demand for the price in the long tenn. For the permissible air pollution standards applicable to all air pollutant emitting facilities, enforcement of incentive environmental policy such as bubble, off-set, banking policy or tradeable emission penn its would be ideal in long terms according to the regional characteristics and the number and scale of air pollutant emitting facilities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.336-346
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• 2009

As a follow-up survey of A Study of Monitoring Method on Exposure Level and Biomarkers of Environmental Pollutants-Focused on Ulsan Industrial Comlpex Area, published in 2005, a close examination of the health status was conducted for selected Ulsan residents. Based on the previous study, a total number of 129 subjects were divided into two groups: the exposure group consisted of 39 residents whose blood levels of lead, mercury and/or cadmium were higher than international reference values, and 90 residents of control group with normal levels. Environmental exposure level and its association with health condition were examined by various methods such as questionnaire, analyses of lead, mercury and cadmium in blood and medical examinations. The geometric mean concentrations of lead, mercury and cadmium in blood were respectively $2.07{\mu}g/d{\ell}$ (exposure $2.54{\mu}g/d{\ell}$, control $1.90{\mu}g/d{\ell}$), $5.94{\mu}g/L$ (exposure $8.57{\mu}g/L$, control $5.07{\mu}g/L$), $1.32{\mu}g/L$ (exposure $1.30{\mu}g/L$, control $1.33{\mu}g/L$). The concentrations of the three heavy metals in blood showed lower levels than internationally recommended values except for blood mercury. Also, any abnormal or, peculiar disease, or target tissue damage related to the heavy metals was not observed among the all subjects. Therefore, it can be said that no significant difference of heavy metal concentrations and health conditions was found between the two groups.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.9
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• pp.809-816
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• 2010

An environmental control system is installed to dissipate the thermal load in avionic equipments that are mounted under an aircraft. The operating characteristics of the system change with variations in the control parameters. In this study, an environmental control system was designed and built using R-124 by adopting a vapor compression cycle. The operating characteristics of this system were observed by varying the control parameters, such as refrigerant charging amount, opening of the expansion device, compressor rotation speed, and blower rotation speed. The effect of the control parameters on the environmental control system was analyzed and an optimum control method was identified.

• KIEAE Journal
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• v.10 no.4
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• pp.111-116
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• 2010

The environmental management is essential for construction projects. The environmental management cost for construction projects is used for various purposes to control the environmental pollution and treat the wastes generated from the construction sites. Six construction cases were analyzed to compare the environmental management cost. The proportion of environmental management cost for total construction budget should be higher than 0.70% in redevelopment projects and 0.30% in newly constructed buildings, respectively, but every six construction cases did not meet the legal requirement. Redevelopment projects expanded more environmental management cost than the newly constructed projects especially in noise control and wastes treatment. In case of apartment construction projects, the proportion of environmental management cost of redevelopment buildings is 2.4 times higher than the newly constructed buildings, but in all cases, paid more attention to the noise and waste controlling measures than the wastewater treatment. It is needed to ensure the cost-effectiveness of environmental management for achieving the eco-friendly construction sites.