• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.483-490
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• 2009

The aims of this study were to evaluate the removal efficiency for various pollutants in urban storm runoff by a filtration device, and to determine design parameters depending on filter media properties. Appropriate selection of filter media will affect the size and life time of the filtration device. Sets of column tests were performed in order to evaluate the removal efficiency by perlite and a synthetic resin. An investigation of surface properties including CEC (cation exchange capacity) and zeta-potential suggested that the perlite had a superior adsorption capability for cationic pollutants. TCODcr and turbidity were analyzed to investigate the removal characteristic of particulate pollutant. In both columns, the particles in the collected storm runoff was almost completely capture with a small EBCT (empty bed contact time) of 2.5 minutes. Complete clogging at the EBCT of 2.5 minutes occurred after 630 minutes in the perlite column and 810 minutes in the resin column. The removal efficiency of TCODcr and turbidity at the EBCT of 2.5 minutes decreased to below 70% due to an wall effect. The removal efficiency for dissolved pollutant (SCODcr) was negligible due to the insufficient contact time for adsorption. The removal of heavy metals (Cu, Zn, Pb) was mostly ascribed to the filtration of particles containing metals, since the relationship between CEC and the removal efficiency was not apparent. The result of this study would be valuable for the application of filtration device to control of urban storm runoff.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.3-7
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• 2005

In the present study a feasibility of a novel filtration process using synthetic for secondary effluent reclamation was investigated. Polyurethane was chosen as a filter medium among tested three media. Compressibility and up-flow velocity were changed to determine the optimum operation for the system. An equation was introduced to express the relationship between the removal efficiency and up-flow velocity. In pilot study, the synthetic medium filtration with compression showed very stable effluent quality without clogging trouble, though the system operated with 3 times higher filtration rate and much longer backwashing interval than conventional systems.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.259-270
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• 2017

In this study, field-scale half-saturated bio-filter wetland equipped with recirculation system was operated with stormwater from the paved road, and its operational performance and functions of LID-BMP were analyzed and compared with other facilities. The reduction of TSS, COD, TN, and TP were 92%, 63%, 36%, and 75%, respectively. Comparison of the reduction efficiency were carried out with respect to ratio between surface and catchment areas(SA/CA). In addition, this LID-BMP facility can reduce about 70% of pollutant by treating only 18% of total rainfall runoff. The results show that LID used for this study gave similar efficiency although its ratio was smaller. In addition, comparison study was made between synthetic fiber as a filter media and organic media, which shows that there was not any significant difference between, TSS and TP reduction, but there were large difference in COD and TN removal due to the presence and absence of release of organic carbon. Meanwhile, wetland system in this study equipped with a first-flush capture gave a higher stability in terms of treatment performance.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.68-75
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• 2016

A set of lab-scale polymer synthetic fiber packed column wetlands composing three columns (CW1, CW2 and CW3) with different hydraulic regimes, recirculation frequencies and pollutant loading rates, were operated in 2012. Synthetic fiber tested as an alternative wetland medium for soil mixture or gravel which has been widely used, has very high pore size and volume, so that clogging opportunity can be greatly avoided. The inflow to the wetland was artificial stormwater. All the wetlands achieved effective removal of TSS (94%~96%), TCOD (68%~73%), TN (35%~58%), TKN (62%~73%) and NH4-N (85%~ 99%). Particularly, it was observed that COD was released from the fiber during one distinct period in all wetlands. This was probably due to the degradation of polymer fiber, and the released organic matters were found to serve as carbon source for denitrification. In addition, with longer retention time and frequent recirculation, lower effluent concentration was observed. With higher pollutant loading rate, higher nitrification and denitrification rates were achieved. However, although organic matters were released from the fiber, the lack of carbon source was still the limiting factor for the system since the release persisted only for 40 days.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.231-236
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• 2010

A compressible media filtration process with synthetic fiber media was studied for combined sewer overflows (CSOs) treatment. Since the operation performance of fiber media filtration was dependent on the pattern of CSOs, the flow rate of CSOs was investigated and it was characterized by a big fluctuation. Thus, in this study, the fiber media filtration process was tested with wide range of filtration velocity. The removal efficiency was proportion to the increase in compressibility. As the filtration velocity was increased, the treatment efficiency was decreased and consequently leveled off when the velocity exceeded 750 $m^3/m^2$/d. An exponential equation was introduced to express the relationship between the removal efficiency and up-flow velocity. At columm test, six repetition of filtration and backwash cycle did not after the filtering velocity under the constant pressure condition.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.94-105
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• 2021

Two vertical flow biofilters in series (BFS) employing synthetic fiber (FBF) followed by woodchip (WBF) was investigated in order to assess its potential as an alternative to the typical vertical-horizontal flow configuration in removing nonpoint source pollutants specifically nutrients and organics. These lab-scale column biofilters were operated for 176 days alongside three other columns that were added for control and sampling purposes. The biofilter columns were fed with either a semi-artificial piggery stormwater or artificial stormwater with specific ammonia and nitrate contents. Results reveal that the BFS was more effective than a single biofilter in removing pollutants especially nitrogen. FBF was found to remove up to 100% of ammonia from the stormwater with corresponding increase in nitrate in the outflow which shows evidence of active nitrification. Meanwhile, the succeeding vertical WBF was able to subsequently remove 77% of the nitrate. The effective reduction of nitrate in a vertical flow biofilter was believed to be due to the use of woodchip which can provide a carbon source that is required for denitrification. However, further investigation is needed to support this claim. Nonetheless, the study shows the potential of vertical flow BFS as a nitrogen removal mechanism especially in areas where enough land space for horizontal flow biofilters is limited.

• Journal of Korean Society on Water Environment
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• v.31 no.3
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• pp.262-271
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• 2015

Laboratory study was undertaken to pursue the filter performance of a micro-filter module employing highly porous fiber media under a high filtration rate (over 1,500 m/day), faster than that of any conventional filter process. The effects of filtration rate, head loss, raw water turbidity, and filter aid chemicals on filter performance were analyzed. In spite of the extremely high filtration rate, the filter achieved an attractive efficiency, reducing the raw water turbidity by over 80%. As with other filter systems, the filter aid used (PAC in this study) greatly affected the performance of this particular fiber filter. Long term repetitive runs were additionally carried out to confirm the reproducibility of the filter performance. Finally, a comparison was carried out with other high rate filter systems which are either being tested for use in experimental studies, or are already commercially available.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.2
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• pp.125-139
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• 2017

In this paper, the performance of a synthetic fiber filter aimed at high-speed operation and dosed with different coagulants or filter aids was investigated. Without a coagulant, the filter efficiency was about 62% which was greatly enhanced when three types of coagulants namely PAC, Alum, and $FeCl_3$ were used. Among the coagulants tested, PAC was the most effective, giving 91% filter efficiency, followed by Alum with 90%, and $FeCl_3$ with 78%. PAC worked effectively at a very small range of dose, but Alum was relatively effective in a wide range of concentration. Compared with PAC and Alum, $FeCl_3$ provided more or less contant efficiency regardless of its dose but gave the poorest filter efficiency. Moreover, as the inflow turbidity increased, headloss increased and the efficiency decreased at any dose and type of coagulant. The headloss recorded in this particular synthetic fiber filter is not significant as compared to that observed in typical granular filters. The recovery of solids estimated after filter cleaning was about 80% for both PAC and Alum, but poorer at 72% in the case of $FeCl_3$ due to the heavy and large floc characteristics. The recurrence of filter efficiency verified through repetitive filter runs was found to be satisfactory.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.334-343
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• 2019

A lab-scale vertical flow subsurface (VFS) wetland composed of three parallel columns with polypropylene synthetic fiber as main substrate was operated. Piggery stormwater diluted from swine excreta was fed to the wetland on the basis of three different hydraulic regimes or hydraulic retention time (HRT) of 2, 4, and 8 days with daily internal recirculation. Then, monitoring of common water quality parameters was carried out. Unexpectedly, an increase of effluent COD concentration accompanying the appearance of foams was observed during a distinct period in the wetland with HRT 2, 4, and 8 days, successively. Subsequently, a series of experiments was conducted to investigate the origin of the foams. Foams and the increase of COD concentration were found to be induced by the release of organic matter from the synthetic polypropylene fiber which was fed with piggery stormwater. Meanwhile, nitrogen removal was found to be enhanced during a period which overlapped the distinct foaming period signifying that foaming played two important functions in biological nitrogen removal. Foams which form rapidly and then burst easily could hold up and then release oxygen for nitrification. Foams which contain organic surfactants could serve as carbon sources for denitrification as well. Hence, nitrogen removal was enhanced during the foaming stage. After that, COD concentration decreased slowly to a level prior to the foaming stage, and nitrogen removal efficiency declined as well.