• KCID journal
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• v.14 no.2
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• pp.181-193
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• 2007

The characteristics of non-point source pollutant loads in middle-stream of Nakdong River Were studied through analysis of pollutant loads of 8 sub-watersheds divided based on administrative district. The pollutant concentration of each sub-watershed was collected from Nakdong-River Water Research Institute and Daegu Regional Environmental Office, respectively. Pollution items analysed in this study were BOD, SS, T-N and T-P. High degree of non-point pollution was observed from Gumi, Goryeong, Gyeongsan, Daegu and Sungju, and pollution was usually increased during rainy season. This result indicates that a given pollution condition within the watershed can be more sensitive than location factor to the level of water quality. The main sources of non-point pollution were population and livestock, as well as landuse factor, and were found to significantly contribute to the water pollution. Alternative solutions for controlling pollution sources, therefore, should be provided to meet target levels of water quality in this region.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.649-654
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• 2000

Field experiment was performed from August 1996 to June 2000. The pilot plant was installed in Konkuk University and the effluent from septic tank of school building was used as an influent to the treatment basin. The treatment basin was composed of sand and reed. Average removal rate of BOD, SS was about 75.9%, 73.4%, respectively. T-P removal rate was about 47.3%, and T-N removal rate was 19.6%. The reason for poor T-N removal might be due to high influent concentration and short retention times. As operation period increased, BOD removal rates were increased, and SS and T-P removal rates did not change significantly, but T-N removal rates were decreased.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.450-452
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• 2016

The effect of channel doping on L-shaped Tunneling Field-Effect Transistors (TFETs) have been investigated by 2D TCAD simulation. When the source doping is over $10^{20}cm^{-3}$, the subthreshold swing (SS) is abruptly decreased, and when drain doping concentration is below $10^{18}cm^{-3}$, the leakage current in the negative voltage is reduced.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.20-25
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• 2021

Milking parlor wastewater contains high concentration suspended solid (SS), nitrogen, and/or phosphate as well as organic compounds. A new biological wastewater process by magnetic separation, magnetic activated sludge (MAS) process, was applied to milking parlor wastewater treatment process. A three step wastewater treatment process of coagulation sedimentation / ammonia stripping (C/S), magnetic activated sludge process and contact oxidation (CO) was proposed for removal of these pollutants. First step, C/S process recovered 96% TN and 96% PO₄^3--P as resource for fertilizer from the wastewater. 81% biochemical oxygen demand (BOD) in wastewater was removed after MAS process. As a results, all pollutant concentrations satisfied Japanese effluent standards. Most of residual BOD and SS were removed by the CO process. It was estimated that the proposed process could reduce the process space to 1/7.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.170-174
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• 1997

Constructed wetland system was studied to treat wastewater from industrial complex in rural area. Pilot plant at the Baeksuk Nongkong Danzi in Chunahn-City was used for field study. For the DO, the effluent concentration was higher than the influent concentration and it implies that natural reaeration supplies enough oxygen to the system. For the SS, the effluent concentration was consistently lower than the water quality standard even though the influent concentration varied significantly, which showed that SS was removed by the system effectively which is consist of soil and plants. For the BOD and COD, the average removal rate of them were 56% and 43%, respectively, therefore, the effluent concentration could not meet water quality standards when influent concentration was high. The removal rate of BOD and COD can be improved by supplemental treatment in addition to this system if necessary. For the T-N and T-P, the influent concentration of them were lower than the water quality standards than no further treatment was needed. Overall, the result showed that constructed wetland system is a feasible alternative for the treatment of wastewater from industrial complex in rural area. For actual application of this system, further study on design factors including loading rate, removal mechanism, and temperature effects is required to meet water quality standard consistently. Compared to existing systems, this system is quite competitive because it requires low capital cost, almost no energy and maintenance, and therefore, very cost effective.

• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.163-172
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• 2004

In this paper, the sub-soil storage system for utilizing urban instream flow of rainfall runoff was developed and examined through experiments. The artificial rainfall facility and sub-soil storage were installed in the experimental area. The effect of the water qualify improvement and the storage effect were analyzed through the several experiments. Through the experiments of rainfall intensity variation, which are the rainfall intensity of 20mm/hr, 30mm/hr, 40mm/hr, 50mm/hr was indicated SS concentration can be reduction until 68％. Also, the ration of the storage volume is varied from 42.8％∼79.9％ based on the rainfall intensity. The reduction rate of the BOD, CO $D_{Mn}$, SS, T-N, T-P was 30％, 42％, 68％, 39％, 26％. As the result, water quality of runoff and efficient of runoff reduction by the system are much improved. The rainfall runoff with the installation of sub-soil storage could be used for instream flow.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.3
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• pp.134-139
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• 2004

A study was made on the synthesis of a carbonate base nitrogen-free deliming agent using a non-phosgene compound applicable to the deliming process, which is one of the biggest sources of pollutant increasing the T-N concentration in the effluent from the leather making processes. And also studied on the possibility of using the agent in the deliming process. Through measurement of T-N, BOD, COD and SS in the effluent after the agent is used, contents of Ca and Cr and TS in the leather after the deliming process were measured, by which deliming efficiency, influences to the physical properties of the chromium tanned leather and reducing effects of T-N, BOD, COD and SS concentrations in the effluent could be confirmed. Thus an eco-friendly study has been conducted.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.733-744
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• 2013

This study was to investigate characteristics of Seoho watershed in Suwon city. $BOD_5$ and SS were selected due to the one of the important factors of the water qualities. Monitoring was conducted monthly for four years during the non-rainfall time. Also, we have been monitored $BOD_5$, $COD_{Mn}$, SS, TN and TP with two times sampling after the rainfalls. The highest concentrations of $BOD_5$ and SS were observed in downstream compare with upstream and midstream during the non-rainfall time. No change was observed in $BOD_5$ and $COD_{Mn}$ during the non-rainfall time and after the rainfalls. The monitoring result indicated that the concentration of SS was the highest in downstream after the rainfalls. We have collected the samples two times after the rainfalls. The rainfall intensity in first sampling was two times higher than second sampling. TN and TP concentrations were increased with increasing the rainfall intensity at all stream. The ESB (Ecological Score of Benthic macroinverterbrate community) index was used to evaluate the statement of stream. ESB results were identified that the upstream is protected waters and the down and midstream is reformed waters. EBS analysis results indicated that the Seoho watershed was ${\beta}$-mesosaprobic at all stream.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.648-657
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• 2006

Characteristics of water quantity and quality of the Anyangcheon were analyzed through many field measurements and the distributed hydrologic simulation model, Soil and Water Assessment Tool (SWAT). Event mean concentrations (EMCs) and baseflow mean concentrations were calculated from the data and the daily runoff were simulated by SWAT. The runoff was divided into the direct runoff and the baseflow. Using those values and quantity and quality data of release from the wastewater treatment plant (WWPT), unit loads of BOD, COD, SS, $NO_2-N$, $NO_3-N$, $NH_3-N$, and Dis-P were derived. EMCs of BOD and SS were even higher than the baseflow mean concentrations. The total runoff from October to April (7 months) of 2004 was just 13.5%, since the rainfall usually is concentrated in summer season. Futhermore BOD and SS were loaded during the event by 50.9% and 70.9%, respectively and over three quarters of total COD, $NO_2-N$, $NO_3-N$, $NH_3-N$, and Dis-P were flowed into the Anyangcheon during the remaining period. Therefore, the efficiency of WWPT for COD, $NO_2-N$, $NO_3-N$, $NH_3-N$, and Dis-P should be intensified from Oct. to Apr. and the runoff quality management of BOD and SS should be planned during the summer season.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.110-118
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• 2016

We compared germination efficiency for somatic embryos (SE) of Liriodendron tulipifera using semi-solid (SS), temporary immersion bioreactors (TIB), and continuous immersion bioreactors (CIB) to produce vigorous plants. The bioreactors were designed to be immersed in liquid media with plantlets with an adjustable immersion time. TIB and CIB improved germination rates up to 80.86% and 95.21%, respectively, however, CIB produced more hyperhydric plantlets than TIB. The height of plantlets in TIB was significantly higher than for those in CIB. Fresh weights of plantlets grown in CIB of were significantly lower than for those grown in TIB. The lowest chlorophyll concentration was found in in vitro plantlets from CIB. We examined abnormally developed leaves, stems, and apical zones of in vitro plantlets that were produced in CIB. Among the three types, SS showed the highest stomatal density and the shortest stomatal length in in vitro plantlets. After acclimatization, plants from CIB exhibited the lowest values in biomass, such as height, root collar diameter, leaf fresh weight, leaf length, leaf width, petiole length, petiole diameter, and leaf area. Photosynthesis and transpiration rates of ex vitro plants were not significantly different among the three culture types, but stomatal conductance was higher in TIB than in the SS and CIB. Therefore, the results suggest that TIB is the preferable bioreactor to improve in vitro plantlet regeneration of L. tulipifera. TIB-originated plants showed higher growth rate than SS and CIB after transferring to soil.