• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.3
• /
• pp.107-118
• /
• 1993

Continuous increasing of impervious area due to urbanization and rainfall quantity due to environmental changes aggravate flooding risk in low land area. Therefore. Seoul municipal authorities go on securing an ample budget for reinforcement and establishment of inner water and inland drainage pumping facilities. But. there is no investment for developing optimal operation rules for appropriate application of existing facilities. In this study. fuzzy control techniques are developed. and applied to 57 stations of inner water and inland drainage pump for model assessment. In these results. fuzzy models have more efficiency in the inland flooding protection than the existing pump operation rule by water level in the same conditions.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.11 no.3
• /
• pp.1731-1738
• /
• 1969

1. For the purpose of analyzing the plan of new reclamation project and its evaluation, actual studies for the existing polders are required. 2. The variations of the salt content of soil, yields and staus of its plantation have been studied for six areas reclaimed in relatively recent years, including Kangwha, Daechon, Chopo, Eushin, Kwangyang and Chinkyo. 3. The annual yields from the project were only 52 percent in the first year as compared with kilograms per 10 a. in the Hachirogata polder in Japan. 4. Such a low productivity in the existing polders in Korea is chiefly by the high ground water table, unfavourable conditions of subdrainage in the root zone, and saline damages of existing high salt content. That is because the depth of drainage ditches is too shallow and layout distance between every drainage ditches is also too long. 5. In order to overcom such a uncertiainties, the drainagedistance suitable for these areas has been Calculated by using the Donnans formula. Applying to the formula, drainage facilities are so densie that land use capability may be decreased. 6. For the purpose of ensuring the effective desalinization and high land use capability, feasible interval to establish the culvert has been studied in accordance with both formulas of Donnan and Hoogan. 7. In order to accomplish the early desalinization in both areas of new reclamation or existing polders, the problems of internal drainages should be resolved. for this puprose in addition to the endeavour of the personnels actually engaged in such works. The actual support of the related agencies for financial assitance is required.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.6
• /
• pp.78-86
• /
• 2014

Since cellulose nanofibrils (CNF) has large specific surface area and high water holding capacity, it is very difficult task to remove water from the CNF suspension. However, dewatering of CNF suspension is a prerequisite of following processes such as mat forming and drying for the application of CNF. In this study, we evaluated the drainage of cellulose fibers suspension under vacuum and pressure conditions depending on the number of grinding passes. Also, the effect of the addition of cationic polyelectrolyte on dewatering ability of CNF suspension was investigated. Regardless of dewatering condition, the total drained water amount as well as the drainage rate were decreased with an increase in the number of grinding passes. Pressure dewatering equipment enables us to prepare wet CNF mat with relatively higher grammage. The cationic polyelectrolytes improved the dewatering ability of CNF suspension by controlling the zeta potential of CNF. The fast drainage was obtained when CNF suspension had around neutral zeta potential.

• KCID journal
• /
• v.18 no.1
• /
• pp.4-17
• /
• 2011

The standard design methodology was suggested to construct wetland system for reducing non-point source pollution from Saemangeum reclaimed paddy land. To set for the design flow and concentrations, runoff and water quality survey were conducted during the irrigation period in 2008 at Gyehwa reclaimed paddy land located at near Saemangeum lake. It is rational that 1ha is the optimum constructed wetland size. To meet this size, the moderate drainage area of reclaimed paddy field was 50ha under the conditions that rainfall is 30mm, average runoff coefficient is 0.83, and runoff capture ratio is 0.6. At these condition, the runoff volume from 50ha was 10,520 $m^3/d$ including base flow during irrigation period. To select the optimum wetland system, several case studies were conducted by focusing on the tidal reclaimed land areas having wetland systems in Seokmun. Pond-Wetland system was selected as the standard model because of showing the highest reduction efficiency. Single variable regression equation were delivered to estimate effluent water concentrations from the designed wetland by using long-term monitoring data from the Seokmun experiment site. The effluent concentration from the designed wetland using these equation were showed moderately range.

• Journal of Soil and Groundwater Environment
• /
• v.26 no.1
• /
• pp.34-44
• /
• 2021

Acid mine drainage (AMD) resulting from pyrite oxidation in mining areas, subsequently leads to soil acidification accompanied by lowering pH and high concentration of metals and metalloids in its surrounding environment. Regarding to this, the microbial amelioration has been considered as a promising option for a more cost-effective and eco-friendlier countermeasure, compared to the use of alkaline chemicals. This study was aimed to evaluate influencing factors in microbially-mediated amelioration of acidic soil spiked by simulated AMD. For this, microcosm experiments were conducted by acid-neutralizing bacterial consortium (dominated by Klebsiella sp. and Raoultella sp.) under the various conditions of AMD spikes (0-2,500 mg SO42-/L), together with acidic mine soil (0-100 g) or sphagnum peat (0-5 g) in the 200 mL of nutrient medium. The employed bacterial consortium, capable of resisting to high level of sulfate concentration (up to 1,500 mg SO42-/L) in low pH, generated the ammonium while concomitantly reduced the sulfate, subsequently contributing to the effective soil stabilization with an evolution of soil pH up to neutral. Furthermore, it demonstrates that suitable condition has to be tuned for successful microbial metabolism to facilitate with neutralization during practical application.

• Journal of Environmental Health Sciences
• /
• v.4 no.1
• /
• pp.1-9
• /
• 1977

The survey on the sanitary conditions to the water supply facilities, privy facilities and disposal methods of human excreta in Sindong area of Choonseung-gun, Kangwon Province was carried out during 7 months from May to November, 1976. The results of the survey are as follows. 1) The pump-wells are used in the 1,185 households as 66.7% of 1,775 and are almost private. 2) The materials of drainage floors and drainage are almost cement, and the drainages are good condition. 3) Most parts of dug-wells have been used beyond 9 years after installation, and disinfection of water has not been carried out in the case of 68.1% of total wells. 4) Objectives of water use to the number of households as 60.2% are drinking, kitchen and cleaning. 5) Water consumption per capita day is estimated to be about 22.7% litters. 6) 1,521 households as 85.7% of total 1,775 possess their private privies and the numbers as 80.6% of the private privies are located outside the houses. 7) The privies are needed to be improved much more in the view point of excreting to the ashpile instead of the septic tank in the case of 39.2% of total households. 8) Human excreta as manure are used to the field in the number of households as 82.4 of total 1,316.

• Proceedings of the Korea Water Resources Association Conference
• /
• 1990.07a
• /
• pp.19-19
• /
• 1990

The paper presents the development and applications of physically-based urban runoff analysis model, URAM, which is capable of simulating sewer runoff hydrographs and inundation conditions within a small urban catchment. The model considers three typical flow conditions of urban drainage networks, whichn are overland flow, gutter flow, and conduit flow during a storm. Infiltration, retention storage and flow routing procedures are physically depicted in model. It was tested satisfactorily with field data from a tested catchment having drainage area of 4.91 ha. It was also applied to other urban areas and found to adequately simulate inundation areas and duration as observed during storms. The test results as well as model components are described in the paper.

• Water for future
• /
• v.23 no.3
• /
• pp.329-340
• /
• 1990

The Paper presents the development and applications of physically-based urban runoff analysis model, URAM, which is capable of simulating sewer runoff hydrograhps and inundation conditions within a samll urban catchment. The model coniders three typical flow conditions of urban drainage networks, which are over-land flow, gutter flow, and conduit flow during a storm. Infiltration, retention storage and flow routing procedures are physically depicted in model. It was tested satisfactorily with the field data from a tested catchment having drainage area of 0.049k$m^2$. It was also applied to other urban areas and found to adequately simulate inundation areas and duration as observed during storms. The test results as well as model components are described in the paper.

• The Journal of Engineering Geology
• /
• v.30 no.4
• /
• pp.423-433
• /
• 2020

Direct current (DC) electric fields have been used for electro-osmotic dewatering. Under DC conditions, however, the electrical contact resistance between the electrode and the dewatering material increases considerably during the process of dewatering. Such a circumstance hinders the continuation of effective electro-osmotic dewatering. To reduce this hindrance, an applied pulse electric field with periodic reversals of the electrode polarity should improve electro-osmotic dewatering. In this study, electro-osmotic dewatering under pulse conditions was experimentally investigated for electrode polarity reversals. During the dewatering process, the pulse electric field was able to reduce the hindrance caused by the DC, resulting in an increased final dewatered amount relative to that under a DC electric field. For a constant applied voltage, the reversed polarity condition, under which the electric current passing through the material was almost unchanged with time, yielded the maximum final dewatered amount. This technique can be used to enhance drainage from a water storage facility during a period of extreme drought and the seawater desalination plants using reverse osmosis in drought stricken coastal regions.

• Journal of Korea Water Resources Association
• /
• v.41 no.12
• /
• pp.1173-1185
• /
• 2008

The design methods of the road surface drainage facilities were compared for the improvement of design method. We have developed four computational design models classified by the methods to determine the duration of design rainfall and to analyze the flow of a linear drainage channel. The critical duration was determined by assuming the critical duration to be 10 minutes or by finding the duration of design storm being similar to the travel time of flow by trial and error. The flow of a linear drainage channel was analyzed as the uniform flow or the varied flow. The design models were applied to the artificial road surface drainage facilities with various channel slopes and road shoulder slopes. If the rainfall intensity of the 10 minutes duration was applied, the outlet spacing obtained from the design based on the varied flow analysis was larger than the uniform flow analysis only when the channel slope and the road shoulder slope was small. On the other hands, if the duration of design rainfall was determined by calculating the travel time, the varied flow analysis brought about larger outlet spacing than the uniform analysis for all conditions. However, the model of the critical duration concept and the varied flow analysis resulted in smaller outlet spacing than the current design method employing the rainfall of 10 minutes duration and the uniform flow analysis.