• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.338-347
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• 2005

Horizontal-Flow Roughing Filtration (HRF) is one of altemative pretreatment methods e.g. prior to Slow Sand Filtration (SSF). However, some of its limitations are that the effluent quality drops drastically at higher turbidity (>200 NTU) and at higher filtration rate (>1 m/h). To overcome these drawbacks, we suggested Direct Horizontal-Flow Roughing Filtration (DHRF), which is a modified system of Horizontal-Flow Roughing (HRF) by addition of low dose of coagulant prior to filtration. In this study to optimize the DHRF configuration, a conceptual and mathematical model for the coarse compartment has been developed in analogy with multi-plate settlers. Data from simple column settling test can be used in the model to predict the filter performance. Furthermore, the model developed herein has been validated by successive experiments carried out. The conventional column settling test has been found to be an handy and useful to predict the performance of DHRF for different raw water characteristics (e.g. coagulated or uncoagulated water, different presence of organic matter, etc.) and different inital process conditions (e.g. coagulant dose, mixing time and intensity, etc.). An optimum filter design for the coarse compartment (grain size 20mm) has been found to be of 3 m/h filtration rate with filter length of 4-4.5 m.

• Journal of Soil and Groundwater Environment
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• v.15 no.4
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• pp.1-12
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• 2010

Well production by a riverbank filtration facility with multi-radial collector well systems in Jeungsan-ri, Changnyeong gun, Korea was evaluated. In this study, the drawdown at collector wells due to pumping and groundwater inflow rates along the horizontal arms of the collector wells were computed through numerical simulations. Sensitivities of the well production to hydraulic conductivity and well flow coefficient, which represents the resistance to the flow from the aquifer to the horizontal arms, were analyzed. Simulation results showed that, with given proposed pumping rate conditions, the drawdown in the caisson exceeded maximum drawdown constraints in the study site and the adjustment of the pumping rate at each well is needed. The drawdown is affected by the hydraulic conductivity of the main aquifer and the well flow coefficient, which means the profound field investigation of the study site is needed to accurately estimate the efficiency of riverbank filtration through radial collector wells.

• Journal of Soil and Groundwater Environment
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• v.13 no.2
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• pp.54-61
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• 2008

The drawdown distribution due to pumping by horizontal or slanted wells is analyzed by numerical modelling. In the numerical modelling uses 1-D discrete element feature included in commercial groundwater modeling program FEFLOW (version 5.1) and the results are compared with the semi analytic solution which uses superposition of successive point sources proposed by Zhan and Zlotnik (2002). Results of the numerical modeling agree well with the semi analytic solution except for very near field region of sink sources. The drawdown distribution due to pumping in riverbank filtration(RBF) plan site can be evaluated quantitatively by the numerical modeling in this study.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.176-177
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• 2005

KOWACO - ChangWon Branch - have conducted the new study which aimed to improve flocculation performance in Mixers. The Purposes in this study were increasing flocculation efficiency by finding significant factor which was affected flow characteristics. In the result of this research we modified the error in equation of G-value and RPM which have been used till quite recently. Also we developed program auto-calculating G-value and RPM and then we had made their statistical list. We had conducted experiment with flocculation Mixer's model sized 1/10 by PIV's method. We analysed characteristic of all flow fields by changing case such as changing direction of flocculator roatation etc.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.1-10
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• 2009

Groundwater flow due to intake of horizontal collector well in riverbank filtration site was analyzed by use of numerical groundwater modeling program (FEFLOW 5.1). Drawdowns of groundwater table nearby collector well were evaluated according to variations of several conditions; pumping rate, thickness of aquifer, offset distance from well to shore line of stream, conductance of streambed. It is observed that the drawdowns of groundwater table are clearly changed according to the variations of these conditions. The results of sensitive analysis shows that the thickness of alluvial aquifer and the offset distance are more sensitive than the conductance of streambed in evaluation of drawdown. This result implies that hydrogeological conditions, as like thickness of aquifer and its distribution in the site are important factors in site selection and evaluating the availability of riverbank filtration intake using horizontal collector well system. It is also revealed that numerical modeling using FEFLOW with 1-D discrete element feature can give efficient quantitative evaluation of horizontal collector well and estimation of availability of riverbank filtration site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.56-63
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• 2018

The management of Combined Sewer Overflows(CSOs) and Separated Sewer Overflows(SSOs) discharge directly to the effluent system in an untreated state, which occurs when the facility capacity is exceeded due to heavy rain, has become an important issue in recent years as the heavy rain becomes a regular phenomenon. Despite the continuous development of filtration technology, targeting densely populated urban areas, CSOs are rarely applied. Therefore, this study was carried out to optimize the process to apply CSOs in a pilot-scale horizontal flow filtration system with a rope-type synthetic fiber. The research was carried out in two steps: a preliminary study using artificial samples and a field study using sewage. In the preliminary study using an artificial sample, head loss of the filter media itself was analyzed to be approximately 1.1cm, and the head loss was increased by approximately 0.1cm as the linear velocity was increased by 10m/hr. In addition, the SS removal efficiency was stable at 81.4%, the filtration duration was maintained for more than 6 hours, and the average recovery rate of 98% was obtained by air backwashing only. In the on-site evaluation using sewage, the filtration duration was approximately 2 hours and the average removal efficiency of 83.9% was obtained when belt screen (over 450 mesh) was applied as a pre-treatment process to prevent the premature clogging of filter media. To apply the filtration process to CSOs and SSOs, it was concluded that the combination with the pre-treatment process was important to reinforce the hydraulic dimension for the stable maintain of operation period, rather than efficiency. Compared to the dry season, the quality of incoming sewage was lower in the rainy season, which was attributed to the characteristics of the drainage area with higher sanitary sewerage. In addition, the difference in removal efficiency according to the influent quality of the wet season and dry season was small.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.63-71
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• 2018

The particle filtration mechanisms in an infiltration trench should be varying due to the different hydraulic conditions during stormwater runoff. The understanding of these variations associated with different filtration mechanisms and their effect on the particle removal efficiency is of vital importance. Therefore, a LID (Low Impact Development) system comprising of an infiltration trench packed with gravel and woodchip was investigated during the monitoring of several independent rainfall events. A typical rainfall event was divided into separate regimes and their corresponding flow conditions as well as filtration mechanisms in the trench were analyzed. According to hydraulic conditions, it was found out that filtration changes between vertical and horizontal flows as well as between unsaturated, saturated, and partially-saturated flows. Particle separation efficiency was high (55-76%) and was mainly governed by physical straining during the unsaturated period. It was then enhanced by diffusion during the saturated period (75-95%). When the trench became partially saturated at the end of the rainfall event, the efficiency decreased which was believed to be due to the existence of a negatively charged air-water interface which limited the removal to positively charged particles.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.359-364
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• 2012

In order to prevent the decrease in well efficiencies due to friction in the axial flow in long, large-diameter laterals, a multi-diameter lateral was devised and tested through lab-scale sand-box experiments to assess its performance. In the experiment, three different production rates were applied over the multi-diameter and the three single-diameter laterals to obtain the hydraulic head distributions for each, which was used to assess the performance of the laterals. Results elucidated that the multi-diameter lateral reduced the material cost by more than a third, in comparison to the single-diameter lateral, while maintaining the production rate at higher than 93%, proving its superiority. Furthermore, results indicated that exit velocities exceeding 0.8 m/sec in horizontal wells tended to distort the hydraulic head distribution near the exit, providing evidence of its inefficiency.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.9-17
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• 2014

PURPOSES : The purpose of this study is to assess removal efficiency of non-point pollutants and applicability for non-point pollutant reduction facilities by conducting the demonstration project operation. METHODS : In order to analyze removal efficiency of non-point pollutants for facilities such as a grassed swale, a small constructed wetland, a free water surface wetland, a horizontal sub-surface flow wetland, and a sand filtration, the field data including specifications of facilities, rainfall, inflow and runoff rainfall effluent etc. was acquired after occurring rainfall events, and the acquired data was analyzed for removal efficiency rate to assess road non-point pollutants facilities using event mean concentration (EMC) and summation of load (SOL) methods. RESULTS : The results of analyzing rainfall effluent, non-point pollutant sources showed that total suspended solid (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), chrome (Cr), zinc (Zn), and lead (Pb) can be removed through non-point pollutant reduction facilities by 60.3% ~ 100%. Especially removal efficiency of TSS, COD and BOD is relatively higher than removal efficiency of other non-point pollutant sources in all kind of non-point pollutant facilities. CONCLUSIONS : Based on the result of this study, even though natural type of non-point pollutant reduction facilities for roads occupy small areas comparing with drainage basin areas, most of non-point pollutant sources would be removed through the facilities.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.351-358
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• 2012

BACKGROUND: Constructed wetlands for wastewater treatment are vegetated by wetland plants. Wetland plants are an important component of wetlands, and the plants have several roles in relation to the livestock wastewater treatment processes. The objectives of this study were to investigate the growth characteristics and nutrient absorption of water plants in constructed wetlands for treating livestock wastewater. METHODS AND RESULTS: In this study, livestock wastewater treatment plant by constructed wetlands consisted of $1^{st}$ water plant filtration bed, $2^{nd}$ activated sludge bed, $3^{rd}$ vertical flow(VF), $4^{th}$ horizontal flow(HF) and $5^{th}$ HF beds. Phragmites communis TRINIUS(PHRCO) was transplanted in $3^{rd}$ VF bed, Iris pseudoacorus L(IRIPS) was transplanted in $4^{th}$ HF bed and PHRCO, IRIPS and Typha orientalis PRESEL(THYOR) were transplanted in $5^{th}$ HF. Growth of water plants in constructed wetlands were the highest in October. The IRIPS growth was higher than other plant as 264 g/plant in October. The absorption of nitrogen and phosphorus by IRIS were 3.38 g/plant and 0.634 g/plant, respectively. The absorption of K, Ca, Mg, Na, Fe, Mn, Cu and Zn by water plants were higher in the order of IRIPS > THYOR > PHRCO. CONCLUSION(S): The absorption of nutrients by water plants were higher on the order of IRIPS > THYOR > PHRCO in constructed wetlands for treating livestock wastewater.