• Asian-Australasian Journal of Animal Sciences
• /
• v.31 no.5
• /
• pp.763-772
• /
• 2018

Objective: Swine manure in Korea is separated into solid and liquid phases which are composted separately and then applied on land. The nutrient accumulation in soil has been a big issue in Korea but the basic investigation about nutrient input on arable land has not been achieved in detail. Within the nutrient production from livestock at the national level, most values are calculated by multiplication of the number of animals with the excreta unit per animal. However, the actual amount of nutrients from swine manure may be totally different with the nutrients applied to soil since livestock breeding systems are not the same with each country. Methods: This study investigated 15 farms producing solid compost and 14 farms producing liquid compost. Composting for solid phase used the Turning+Aeration (TA) or Turning (T) only methods, while liquid phase aeration composting was achieved by continuous (CA), intermittent (IA), or no aeration (NA). Three scenarios were constructed for investigating solid compost: i) farm investigation, ii) reference study, and iii) theoretical P changes (${\Delta}P=0$), whereas an experiment for water evaporation was conducted for analyzing liquid compost. Results: In farm investigation, weight loss rates of 62% and 63% were obtained for TA and T, respectively, while evaporation rates for liquid compost were 8.75, 7.27, and $5.14L/m^2{\cdot}d$ for CA, IA, and NA, respectively. Farm investigation provided with the combined nutrient load (solid+liquid) of VS, N, and P of 117.6, 7.2, and $2.7kg/head{\cdot}yr$. Nutrient load calculated from farm investigation is about two times higher than the calculated with reference documents. Conclusion: The nutrient loading coefficients from one swine (solid+liquid) were (volatile solids, 0.79; nitrogen, 0.53; phosphorus, 0.71) with nutrient loss of 21%, 47%, and 29%, respectively. The nutrient count from livestock manure using the excretion unit has probably been overestimated without consideration of the nutrient loss.

• Journal of Wetlands Research
• /
• v.20 no.4
• /
• pp.304-313
• /
• 2018

Agricultural land reclamation in Saemangeum tidal land project is mostly planned to be completed by 2020. Irrigation water for the land is required to be prepared by that time. However, water quality for the irrigation sources is barely meet the target concentration. This paper described the reduction effect of and policy consideration for best management practices (BMPs) which were fertilizer prescription by soil test (SO#1), mixed application of SO#1 and 3 (SO#2), drainage gate control (SO#3), time-release fertilizer application (SO#4), and control (CT). Reduction of paddy runoff was relatively higher in SO#3 (25%) and SO#1 (27%) while lower in SO#4 (9%) and SO#2 (7%) than that in CT. In addition, farmers promised to follow the BMP guidelines but they didn't because of the several problems caused for the BMPs implementation. Thus, it recommended developing an automated control of irrigation gate and paddy water depth and supporing farmers for NPS pollution control and irrigation water reduction.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.13 no.3
• /
• pp.237-244
• /
• 2001

The watershed information of the Mankyung River and Dongjin River is obtained and analysed using the GIS tool. The informations i.e., digital map, land use, point sources, weather station, water quality measurement station, and pollutants load unit are managed by DB system. The slope, rainfall, and generated pollutants loads of COD, TN and TP which are the input data of the rainfall-runoff-pollutants load model are estimated. From the analysis of the collected and generated data, the almost watershed area is composed of agricultural lands except the upstream regions. The population and industrial area are densely located in Cheonju City and Iksan City, whereas the farming areas are widely distributed.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.56 no.1
• /
• pp.45-54
• /
• 2020

In this study, an automatic system for improving the working environment and increasing production efficiency of a laver aquaculture industry in Korea was developed by combining a hydraulic control system and a load cell in a current landing work of the laver. The improved gathering laver system allowed the automatic gathering process of the laver in the sea with the hydraulic control system connected to a cutting machine of the laver on the operating ship, which has been used for gathering the laver semi-automatically in a form of the traditional farming method. The transporting process of the laver from an operating ship to the land was improved as follows. A frame installed on the operating ship and the bag nets were designed and made to hold about 1,000 kg of the laver inside. The bag nets contain the laver on the improved operating ship were tied in knots and hooked on a crane using a load cell. The weight is measured immediately by lifting the bag nets through the load cell system. Weight information is communicated to the fishermen and successful bidders through the application. The advantages of the improved system can help fishermen to fish by improving their working environment and increasing production efficiency. The field survey to improve the landing operation of the laver aquaculture was conducted in Gangjin, Goheung, Shinan, Wando, Jindo, and Haenam in South Jeonnam Province. A total of 10 sites including Gunsan in Jeonbuk Province, Daebu Island in Ansan City, Jebu Island in Hwaseong City in Gyeonggi Province, and Seocheon in Chungnam Province were searched to collect data. Prototypes of the system were tested at the auction house of laver located in Goheung, where laver collection using hydraulic control and landing using road cell could be improved.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.10a
• /
• pp.539-550
• /
• 2006

New Songdo city is currently developing on the reclaimed land on a marine deposit and among the development the four sixty-four(64) stories high rise buildings are under construction at block 125. The ground condition of the site is comprised of a deep seated weathered rock staratum under a soft marine deposit layer. As a foundation system, a bored pile was planned to transmit the applied load to the stable layer. In this study, the behavior of the weathered rock especially locating at a upper part having a weak strength(HWR, MWR) has been evaluated through series of hi-directional pile load test(BD PLT) carried out on the 3 drilled shafts socketed in a weathered rock layer in a design stage. It has been planned to increase the effect of the tests that the length of test piles was prepared short enough to perform the test under a high stress. The summary of the design reflecting the test results has been made up. In addition, the 4 hi-directional pile tests excuted on the working piles during the construction stage for the purpose of confirmation and the evaluation of the adequacy of the pile behaviors have been included in this study.

• Journal of the Korean GEO-environmental Society
• /
• v.7 no.6
• /
• pp.57-65
• /
• 2006

In this study, WASP6 was used to predict the water quality of the reservoir and the lake. This can help the managers make the right choice of water quality policy. The results through studying are below. Raw pollutant load caused by the tourists in pollutant load of the study area takes 91.66% and 92.75% in total amount T-N, T-P. It showed high value when compared to raw pollutant load by land and stock farm and it seems that the main contamination is the population of tourists. From the result of the prediction model, BOD will increase about 1.5 times, T-N and T-P will be 1.5 times in 2012. It means that some counter plan is needed to reduce pollutant load. Enviroment grade of Suokjeong reserver is in I~II grade which is in good condition comparatively. However, the water contamination will be in poor as the year passes. when considering T-N T-P, which are the nutrients to control eutrophication, the concentrated administration about contamination sources is in urgent.

• Journal of Korean Association for Spatial Structures
• /
• v.7 no.1 s.23
• /
• pp.63-70
• /
• 2007

To improve the land use of urban, Construction of the circular steel column is required recently. The circular steel columns have a advantage for improving a load carrying rapacity as wall as reducing a effective section area. However, the circular steel columns under service load, such as earthquake, shows a tendency to cause local buckling and large deformation. To prevent these phenomena, use of longitudinal stiffeners is considered. The application of longitudinal stiffeners at the circular steel columns is expected to increase a load carrying capacity, buckling strength and seismic performance of circular steel column. However, increasing the loading carving rapacity of buckling which constructed the longitudinal stiffeners, was not investigated yet. Therefore it needs study on effect of longitudinal stiffener in pipe-section steel pier. In this study, the load rallying capacity of buckling of steel pier was investigated by using elastic-plastic finite element analysis considered geometrical and material non-linearity. Also, this study investigated the effect of longitudinal stiffeners on loading carrying capacity of buckling and the relationship between width and thickness of longitudinal stiffeners. And also, a Influence of longitudinal stiffeners on seismic performance of circular steel columns was investigated by numerical analysis

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.11
• /
• pp.9-17
• /
• 2019

Interest in renewable energy is rapidly growing around the world. One of the most popular renewable energy sources is solar power, and photovoltaic (PV) systems are the most representative route for generating solar energy. However, with the growing adoption of solar power systems, the demand for land on which to install these systems has increased, which has caused environmental degradation. Recently, floating PV systems have been designed to utilize idle water surface areas of dams, rivers, and oceans. Because floating PV systems will be exposed to harsh environmental stresses, the safety of such systems should be secured before installation. In this study, the structural robustness of a floating PV system was analyzed by conducting numerical simulation to investigate whether the system can withstand harsh environmental stresses, such as wind and wave loads. Additionally, conventional wind and wave load predictions based on the design method and the simulation results were compared. The comparison revealed that the design method overestimated wind and wave loads. The total drag of the PV system was significantly overestimated by the conventional design criteria, which would increase the cost of the mooring system. The simulation offers additional advantages in terms of identifying the robustness of the floating PV system because it considers real-world environmental factors.

• Journal of Korean Society on Water Environment
• /
• v.35 no.5
• /
• pp.399-408
• /
• 2019

The average annual water quality at Yongchon Bridge, Bonggok 2 Bridge, and Gasuwon Bridge in upstream of Gapcheon in 2018 was Ib grade (good) in organic matters, including BOD and TOC compared to the local environmental standard in Daejeon. However, their monthly changes for TOC partially exceeded the standard during the busy farming season at Bonggok 2 Bridge and Gasuwon Bridge. Although the annual average TP was within the standard, the monthly change at Bonggok 2 Bridge partially exceeded the standard. For Dugyecheon, the annual average water quality in 2018 at Umyeon-dong Bridge and Wonjeong Bridge, which are downstream of the Gyeryong public sewage treatment plant, exceeded the local environmental standard in BOD. COD was exceeded, and TP was within the standard. It seemed that the causes of deteriorated water quality downstream of Dugyecheon were discharges of agricultural water from agricultural land and effluent from the Gyeryong public sewage treatment plant. Assuming the pollution load of 100% based at the Mulangil point of the mainstream of Gapcheon, the ratio of BOD load and TOC load were as high as 58% and 47%, respectively. At the basin of Bonggok 2 Bridge and Mulangil, the loads downstream of Dugyecheon including the Gyeryong public sewage treatment plant were as high as 43% for TN and 56% for TP, respectively, indicating that Dugyecheon had a major impact on the water quality at the mainstream of Gapcheon.

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