• Journal of Environmental Science International
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• v.21 no.8
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• pp.977-988
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• 2012

This study analyzed the characteristics of stormwater runoff by rainfall type in orchard areas and transportation areas for 2 years(2010~2011year). Effluents were monitored to calculate the Event Mean Concentrations(EMCs) and runoff loads of each pollutant. The pollutant EMCs by volume of stormwater runoff showed the ranges of BOD 0.9~13.6 mg/L, COD 13.7~45.2 mg/L, SS 4.1~236.4 mg/L, T-N 2.123~21.111 mg/L, T-P 0.495~2.214 mg/L in the orchard areas, and was calculated as BOD 2.3~22.5mg/L, COD 4.4~91.1 mg/L, SS 4.3~138.3 mg/L, T-N 0.700~13.500 mg/L, T-P 0.082~1.345 mg/L in the transportation areas. The correlation coefficient of determination in the orchard area was investigated in the order of Total Rainfall(0.81) > Total Runoff(0.76) > Rainfall Intensity(0.56) > Rainfall Duration(0.46) > Antecedent Dry Days(0.27). Also, in the case of the transportation area was investigated in the order of Total Rainfall (0.55) > Total Runoff(0.54) > Rainfall Intensity(0.53) > Rainfall Duration(0.24) > Antecedent Dry Days(0.14). As the result, comparing valuables relating to runoff of non-pollutant source between orchard areas and transportation areas, orchard area($R^2{\geq}0.5$ : X3, X4, X5) was investigated to have more influence of diverse independent valuables compared to the transportation area($R^2{\geq}0.5$ : X3, X4) and the difference of discharge influence factor by the land characteristics appeared apparently.

• Clean Technology
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• v.7 no.4
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• pp.251-263
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• 2001

This study was conducted to provide a basic information for recovery plan of Seung-Gi Stream which is a major stream of Incheon metropolitan area. Source and characteristics of pollutants were analyzed and studied. Samples were taken 10 rounds in 5 sections in Seung-Gi stream. Annual pollutants loads and sectional characteristics of pollutants loads were investigated regarding flow rate, pH, DO, SS, $BOD_5$, $COD_{Cr}$, T-P, TKN and concentrations of Zn, Cd, Cu, Cr atoms which enter into Seung-Gi stream during rainy and dry season respectively. As one came close to the Nam-Dong Industrial Complex, sectional discharge loads were heavy and water quality was failed to meet the standard by "Environmental Standard of River Quality". As a result, heavy load of pollutants in Seung-Gi stream was considered to influence negatively the sea water quality of Incheon. Solution plans to solve problems are as follows. First, circulation of treated water at Seung-Gi WWTP(Wastewater Treatment Plant) and retreated water by URC(ultra rapid coagulation) process treat with that. Second, sewage and wastewater is gathered, make it disposed. After then, we circulate treated water. If solution plans be applied, we can predict water quality. Then we could grope for how make to recovery role of Seung-Gi stream as stream.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.83-90
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• 2006

This paper investigates experimentally the fire resistance performance and spatting resistance of high performance reinforced concrete column member subjected to fire containing polypropylene fiber(PP fiber) and cellulose fiber(CL fiber). An increase in PP fiber and CL fiber contents, respectively resulted in a reduction of fluidity due to fiber ball effect. Air content is constant with m increase in fiber content. Compressive strength reached beyond 50 MPa. Based on fire resistance test, severe failure occurred with control concrete specimen, which caused exposure of reinforcing bar. No spall occurred with specimen containing PP fiber. This is due to the discharge of internal vapour pressure. Use of CL fiber superior to control concrete in the side of spatting resistance, localized failure at comer of specimen was observed. Corner of specimen had deeper neutralization than surface of specimen. Specimen containing PP fiber had the least damaged area due to spatting. Neutralization depth ranged between 6 and 8 mm Residual compressive strength of specimen containing PP fiber maintained 40%, which is larger than control concrete with 20% of residual strength. Specimen containing CL fiber had 25% or residual strength.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.232-241
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• 2017

This paper presents an automated cow-feeding system based on an AGV and screw conveyor for domestic livestock farms, which are becoming larger and more commercialized. The system includes a hopper module for loading pellet-type mixed feed at the top of the system, a transfer module mounted with a screw conveyor to transfer feed from the hopper module to the outlet module, an outlet module composed of belt conveyors, and an electromagnetic guided driving-type AGV. The weight of the loaded feed is measured by a load cell located under the transfer module. The system reads the feed discharge information stored in RFID tags installed in each cowshed cell, and a predetermined amount of feed is discharged while the AGV is moving. A cow-feed test system was constructed to determine the design parameters of the screw conveyor in the transfer module that determine the feeding capacity. These parameters include the screw's outer diameter, the screw shaft outer diameter, and screw pitch. The parameters were applied to the finalized cow-feed system construction. A DSP-based main controller and cow-feeding algorithm for different scenarios were also developed to control the system. Experimental results confirmed that the system could supply a total of 21 kg of feed uniformly at 420 g/s for a cowshed cell which has 7 cows. The driving distance was 5 m and the speed was 0.1 m/s. Thus, the proposed system could be applied to standardized domestic livestock farms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.262-269
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• 2016

This study examined the influent of a sulfur denitrification reactor using nitrified effluent from a batch type reactor. The denitrification efficiency was compared according to the injection type. The nitrogen removal effects were compared with the changes in the EBCT and nitrogen concentration of the influent to determine the optimal operation conditions with the selected injection type. A denitrification efficiency evaluation of a reactor according to the change in injection type and up-flow was performed using a lower organic concentration of the effluent than the down-flow because of the re-precipitation of desorbed microbes and spilled solids. In the up-flow type, organics were controlled by the low concentration than the down-flow type because of solid re-precipitation. The T-N removal efficiency of the up-flow type was 73.3~90.2%, which was more that 10% higher that down-flow type. This means that the up-flow type has a great advantage in removing T-N and organics. The T-N removal efficiency by EBCT at 1hr was 47.3%, and was 88.1% and 90.5% by EBCT 3hr and 5hr, respectively. Therefore, the optimal operation conditions to remove nitrogen was considered to be EBCT for 3hr. After careful consideration of rule of law and T-N removal effects, the T-N load factor in the reactor should remain below $0.443kgT-N/m^3{\cdot}day$ to maintain the legal total nitrogen concentration for discharge, which is 20mg/L.

• Journal of Environmental Policy
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• v.11 no.4
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• pp.85-105
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• 2012

In this paper, the energy efficiency of wastewater utilities was evaluated to explore ways to save energy via operational measures. The correlation of each wastewater characteristic parameter to energy was assessed to find a set of parameters that explained most of the variations in energy use among utilities. The results show that increases in inflow, influent COD concentration, and ratio of advanced treatment generally increased the energy use. On the other hand, increases in load factor (influentaverage flow/design flow) reduced the energy use. In the regression analysis, the energy efficiency was highest in the A2O advanced process. On the other hand, the membrane process (among the advanced processes) and the contacted aeration process (among the secondary processes) require more efforts in saving energy. However, the data base system related to energy use must be supplemented in order for more accurate analysis of energy consumption in wastewater treatment facilities. In particular, i) electricity consumption of relay pumps and, ii) energy usage per unit process, iii) pump power usage to discharge treated wastewater in a long distance, if necessary, and iv) alternative energy production and utilization status must be recorded. By utilizing the results of the analysis conducted in this study, it is possible to quantify a level of energy savings needed and establish customized energy saving measures to achieve a certain target level for benchmarking a successful case of wastewater utilities.

• Journal of Environmental Science International
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• v.22 no.3
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• pp.259-267
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• 2013

In this study, non-point source(NPS) contribution was investigated based on flow rates and water qualities of streams into the lake during rainfall events. Event mean concentration(EMC) and the pollution loads were calculated to establish a database for NPS control measurement in the survey area, and so on. The runoff characteristics of NPS were investigated and estimated on the basis of the ratio of an agricultural to forest area in the stream of sub-catch basin during rainfall events. Non-point source pollution loads were also calculated to establish a database for NPS control measure in the upstream lake Chinyang. At a rainfall event, BOD concentrations rise sharply at the early peak time of runoff, however, peaks of TSS concentration were observed at the similar time of peak flow. This was a phenomenon shown at the watersheds caused by forest and geological types. The discharged EMC range was 2.9-4.8 mg/L in terms of BOD. The discharged EMC range was 6.2-8.2 mg/L in terms of SS. The discharged EMCs of T-N and T-P were 1.4-2.5 mg/L and 0.059-0.233 mg/L, respectively. Total BOD loading rate through the 3 tributaries to the lake Chinyang was 1,136 kg/d during dry weather. The upper watershed area of the Nam-river dam in this study was divided into 14 catchment basins based on the Korean guideline for total maximum daily load(TMDL) of water quality pollutants. The higher the agricultural land-use ratio, the more NPS loading rate discharged, but the more occupied a forest area, the lower more NPS loading rate discharged. In an agricultural land-use area more than 20%, the increase of NPS loadings might be dramatically diffused by increasing the integrated complex-use like vinyl-house facilities and fertilizer use etc. according to the effective land-use utilization. The NPS loading rates were BOD 0.3 $kg/ha{\cdot}day$, SS 0.21 $kg/ha{\cdot}day$, TN 0.02 $kg/ha{\cdot}day$, TP 0.005 $kg/ha{\cdot}day$ under less than 10% agricultural land-use. In agricultural land-use of 20%-50%, these values were investigated in the range of 0.32 $kg/ha{\cdot}day$-0.73 $kg/ha{\cdot}day$ for BOD, 0.92 $kg/ha{\cdot}day$-3.32 $kg/ha{\cdot}day$ for SS, 0.70 $kg/ha{\cdot}day$-0.90 $kg/ha{\cdot}day$ TN, 0.03 $kg/ha{\cdot}day$-0.044 $kg/ha{\cdot}day$ for TP.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1343-1362
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• 2015

As a result of analysis based on the observed data for BOD, COD and TOC in order to manage non-biodegradable organics in the Geumho River, COD/BOD ratio was analyzed as the occupying predominance proportion. In this study, the classification(changes in water quality measurement : increase, equal, decrease) and measurement of BOD and COD were analyzed for trends over the past 10 years from 2005 to 2014 in the Geumho River. The Geumho River is expected to need non-biodegradable organics management because BOD was found to be reduced 61.1% and COD was found to be increased 50%. As a result of the analysis of land use, the Geumho-A is a unit watershed area of $921.13km^2$, which is the most common area that is occupied by forests. The Geumho-B is a unit watershed area of $436.8km^2$, which is the area that is highest occupied by agriculture and grass of 24.84%. The Geumho-C is a unit watershed area of $704.56km^2$ accounted for 40.29% of the entire watershed, which is the area that is occupied by urban of 15.12%. Load of non-biodegradable organics, which is not easy biodegradable according to the discharge, appeared to be increased because flow coefficient of COD and TOC at the Geumho-B were estimated larger than 1 value. The management of non-point sources of agricultural land is required because the Geumho-B watershed area occupied by the high proportion of agriculture and field. In this segment it showed to increase the organics that biodegradation is difficult because the ratio of BOD and TOC was decreased rapidly from GR7 to GR8. Thus, countermeasures will be required for this.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.387-394
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• 2000

Water pollution characteristics were investigated in the Kyongan stream and major inlet parts of Paltang Reservoir from April to July, 2000. Water quality in the Kyongan stream was extremly deteriorated by treated wastewater discharge at near sewage wastewater treatment plant (SWTP) located in the upstream, and it is likely to influence eutrophication of the lower part of the stream. Water quality of the Kyongan stream showed a typical hypertrophic condition. Influxed concentrations with $NH_4$ and SRP into the main stream from SWTP were declined precipitously as water flowed toward the lower part of the stream, and chlorophyll- a explosively increased in the midstream. Average concentrations of $NH_4$, SRP and chlorophyll-a in the main stream were $1,343\;{\mu}g\;N/l$, $1,779\;{\mu}g\;P/l$ and $188\;{\mu}g\;l$, respectively. Particularly, phosphorus load was very high, and its influence on the algal growth stimulation was remarkable. In comparison with the water quality inflowing into Paltang Resevoir, pollution status of the Kyongan stream was more worse than that in the Pukhan River and the Namhan River. The results of this study indicate that the management of point source, SWTP effluent, is urgent to mitigate eutrophication of Paltang Reservoir, and requires further necessary controls of inorganic phosphorus loading.

• Fire Science and Engineering
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• v.26 no.2
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• pp.1-10
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• 2012

While a performance based sprinkler design method has been widely used in UK and USA according to fire hazards of occupancies, Korean fire safety industry could not yet accept it due to nonstandardization on risk level of various occupancy. Even only two or three spray pattern sprinkler was produced in Korea fire safety industry, therefore, various spray pattern sprinklers have not yet introduced to major occupancies. Spray pattern sprinklers with one of two K value have been used in all occupancies in Korea Market. UK and USA's Fire industry should produced the spray sprinklers with various K-factors and protection area due to performance based sprinkler design requirement. Therefore the fire load density for main occupancies has been investigated in order to compare with installation standard in advanced countries. Eventually a lot of variations in orifice and K factors of standard heads were set up including special heads needed for high hazard areas such as large drop type, enlarged orifice type and early suppression fast response.