• Journal of Korean Society of Water and Wastewater
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• v.23 no.2
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• pp.207-214
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• 2009

This study examines the optimum filtration conditions in pretreatment of seawater desalination by reverse osmosis. For this purpose, Masan bay seawater is treated through a gravity filter column while $FeCl_3$ is added as coagulant. The conditions of coagulantd osage, media depth, filtration rate, and backwash time are evaluated. The study results show that the filtrate quality improved with increasing coagulant dosage, but head loss rapidly increased. After 4mg/L, the unit filter run volume reduced to less than $200m^3/m^2$. Considering the head loss development, 4mg/L is determined as the optimum dosage. The better filtrate qualities are obtained with depth of 100cm than that of 80cm. The two stage filtration, which outperformed the single stage filtration, is suggested for treatment of Masan bay. The filtration rate of 5m/h is decided as the optimum condition considering the head loss development. At 10m/h, the filtrate quality deteriorated even though the extent was minimal, and head loss increased rapidly. The backwash time of 10 min is decided appropriate.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.228-232
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• 2005

Damaged spermatozoa are supposed to be trapped in glass wool. In the respect of this, two glass wool filtration spermatozoa groups (0.5 cm, 1 cm depth) were compared with control group to assay sperm motility, HOS values, and vital rate by CFDA/PI staining method following glass wool filtration. The motility of canine sperm extended with PBS+PVP after glass wool filtration was lower in both filtrated groups than that of the control group (p<0.01) and the same significant difference was also shown in canine semen extended with Tris buffer (p<0.01). The motility of canine sperm diluted with PBS+PVP was higher than that diluted with Tris buffer in the same experimental groups (p<0.05). The motility of control group was not significantly decreased until 2 hours immediately after extending, however, the motility of both glass wool filtrated spermatozoa were significantly decreased as time passed until 2 hours after filtration (p<0.01). At each time for assay (immediately, 30 min, 2 hours after filtration), the motility of canine sperm of control group was higher than the filtrated groups (p<0.05), whereas the motility of 0.5 cm depth group was higher than 1 cm depth group at the immediate time after filtration (p<0.05), 30 minutes later (p<0.05) with no difference at 2 hours. No difference was shown among the experimental groups in HOS values of canine sperm after glass wool filtration. The vital rate assayed by CFDA/PI staining of both filter groups was higher than the control group (p<0.05).

• Particle and aerosol research
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• v.5 no.4
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• pp.159-170
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• 2009

A depth filter medium was newly designed in order to achieve high collection of dust and low pressure drop in this work. Multilayer depth filter media consist of an upstream layer of highly porous structure which allows particles to pass through and to follow by one or more downstream layers to hold the particles inside the media. For each filter media, flat sheet and pleated module were made of newly developed depth filter media and filter media of commercial products. Commercial depth filter cartridge for gas turbine air intake cleaning were used as reference for filtration area and pleat geometry of pleated modules. This work attempts to evaluate and compare the newly developed depth filter medium and two commercial filter media in terms of filtration parameters such as air permeability, initial pressure drop, particle retention and pressure drop variation with dust loading. According to the close examination the newly developed depth filter showed better performance compared to the commercial depth filter media.

• Particle and aerosol research
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• v.8 no.4
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• pp.133-141
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• 2012

A new depth filter media was designed and samples of flat sheet as well as cartridge assembly were prepared and tested to evaluate the filtration performance and compare with the commercial product. The arrangement of the depth filter media layers is important to reach the optimal filtration parameters like filter pressure drop, particle collection efficiency and dust holding capacity. Initially, both flat sheet samples of new media and commercial product have been tested using standard test units. Tests with new depth filter media cartridges of various pleat count were conducted in order to find the optimal pleat count which would represent the lowest pressure drop. These tests give an insight on how the pleat count and the assembly configuration affect the performance of the depth filter media cartridge. By comparing the samples with a commercial product we could confirm relatively high filtration performance of the sample cartridge with pleat count 150 made of new depth filter media. The cartridge with the same pleat count exhibits better performance without the outer mesh.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.3
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• pp.361-369
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• 2004

A metal fiber bed has seldom been applied to the practical filtration process despite its excellent mechanical and chemical stability. The filter-bed used in this work was highly porous with open structure, of which apparent porosity was 80 ∼ 90%. Although pressure loss across the filter-bed was very low, separation efficiency was found to be quite high. This paper focuses on the basic filtration mechanisms of a metal filter-bed and a thin ceramic filter from fly ash for reference. The experimental parameters were face velocity, dust loading and porosity of filter-bed. Pressure drop increased with increasing face velocity and dust feeding load for both filters. It also showed that dust particles deposited in the deep flow path, finally resulting in clogging the pore channels. It thereby indicates that the dominating mechanism of the metal filter-bed would be depth filtration. Meanwhile, the thin fly ash composite filters trapped the aerated dust mainly on the surface of the filter medium, so that the instantaneously formed dust layer might cause a steep increase of pressure drop across the filtration system.

• Membrane and Water Treatment
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• v.10 no.2
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• pp.105-112
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• 2019

On the purpose of conform the more stringent government regulation for turbid stormwater from construction sites, the feasibility and availability of synthetic fiber placing after the conventional protection barrier were tested in this study. Initially, comparative work on the filtering performance of fiber media and conventional gravel filter was carried out, 27% higher filtration capacity was obtained under the similar operational conditions. The filter efficiency was about 20 to 52% with a varying filter depth of 5 to 15cm, presuming at extreme storm flow conditions (800-1500 m/day of filtration rates). Fiber filter was found to have a similar filtration prosperity as grain media; namely, the separation efficiency is directly and inversely proportional to filter depth and rate, respectively. The effects of filter aid (polyaluminium chloride) on filter performance was also investigated, it greatly affected the turbidity reduction at the dosage of 2 mg/L. At the time of breakthrough, a simple filter washing was carried out, herein, the solid recovery achieved over than 88% and greatly determined by operational parameters. Based on the operational data, the empirical models aimed for predicting filtration efficiency were established, which can effectively determine the required filter depth and filtration area in field.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.120-131
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• 2011

A pilot-scale experiment of floodplain filtration with a filtration depth of 3.6m was performed employing flood/rest type raw-water supply system in an effort to find ways to improve river water quality by additional treatments of discharged effluent from sewage treatment plant. Soil samples were taken from 3 sites including Gumi, Daegu and Gimhae along the Nakdong river. Reductions of infiltration rates following increases in operating time was investigated in each soil sample, along with the analysis of removal efficiencies of various pollutants according to different depths and infiltration rates. The results show incremental development of clogging on the soil surface with increases in operation time, and illustrate exponential decrease in the infiltration rate. The time required for the removal of the clog from the soil surface was longer than 2 weeks for all soil samples analyzed. The stable infiltration rates for soils were 5 m/day for Gumi and for Daegu and Gimhae was 1 m/day. In unsaturated soils dissolved oxygen levels increased following the increase of filtration depth, suggesting that alternating application of flood and rest for raw-water supply effectively keeps the soil environment aerobic. For all soils, the nature of pollutant removal depending on the depth of filtration remained the same regardless of the infiltration rate. Most of the BOD and turbidity were removed within 1.2 m, about 30% of COD was removed within 3.6m and was expected to be removed further with increases in filtration depth. Nitrification occurred near the surface of all soils; however there was no significant removal of nitrogen in the filtration depths tested in this study. Although removal rate of phosphorus was low for Gumi's soil, it was high enough for other soils, suggesting that the method developed in this study could significantly improve river water quality.

• Journal of Environmental Science International
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• v.13 no.9
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• pp.799-806
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• 2004

The filtration tests were made in cell with a low concentrated suspension. The suspension with a concentration of $C_{M}$=1.14～2.67$\cdot$$10^{-3}$ g/g consists of paper paint and water. The particles in the suspension have a particle size x<1${\mu}m$. The used depth filters consists of glass fibres, which are coated by polymer. The filtration in depth filters accorded in different mechanism, which were explained by physical models. The model which would be allows to make a promise of the filtration reaction. This filter media allows to get a high filtration time and a good separation rate. The Particle distribution is measured by a photon correlation spectroscopy(PCS). PCS measures particle sizes 0.03 ${\mu}m$${\mu}m$ in the suspension. The filtered suspension has a very low concentration Co{\le}5{\times}10_{-4}$ g/g of solid in sample. The PCS also informs us about the number of the particles in the suspension. The makes it possible to calculate the concentration of the in sample.

• Membrane Journal
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• v.19 no.3
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• pp.173-182
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• 2009

Depth cartridge filters are widely used in various kinds of manufacturing process of industrial fields. This study focused on the explanation of depth and surface filtration mechanism, manufacture process and also survey its major company and market trend. Furthermore, the failure mode and major factor which can be occurred in use, and the reliability test of liquid cartridge filter were studied.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.873-878
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• 2014

The applicability of carbon nanotube (CNT) to slow sand filtration for the removal of bacteria was studied using scanning electron microscope and column experiments. The morphology of CNT were investigated using scanning electron microscope and the CNT looked like a skein serving bacteria favorable site for adhesion. Column experiments were performed over a range of CNT filter depth, pH, and ionic strength. Bacteria removal efficiency was found to increase from 44.15% to 99.95% as the CNT filter depth increased from 1 cm to 5 cm, and 3 cm of CNT filter depth was required for significant removal of bacteria. pH increase from 5.5 to 8.5 decreased the bacteria removal efficiency, due to the electrostatic repulsion between bacteria and CNT at higher pH. Bacteria removal efficiency decreased from 97.25% to 70.90% as the ionic strength increased from 0 mM to 50 mM. This study demonstrated that the CNT can be applied to slow sand filtration for treating microbially contaminated water.