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In this study, ion-exchange fibers to create a cartridge-type, and its adsorption properties were investigated. Properties for the purpose of the test formulation with ion-exchange fibers and nonwovens, respectively, 7:3 and 8:2 were produced as a filter. It was shown that as for adsorption of magnesium and calcius ions by ion-exchange fiber, magnesium ion is slower than calcium ion in the each solution. Also, in the mixture of the magnesium and calcium ions, the adsorption rate of magnesium ion was much slower than that of calcium ion. Finally, Ion-exchange fiber filter has a high adsorption capacity for 6-7 hours and a recycling capacity for 6-7 times, therefore it would be possible to be applied to water treatment.
At the construction site, wheel cleaning systems are installed to prevent dust scattering. However, it is not included in the effluent discharge facility, and it is not applicable to the law on water quality and aquatic ecosystem conservation, so proper management is not possible. In this study, we developed a continuous multistage waste water treatment system related to a nano bubble sprinkler to treat scattered dust from construction sites. In order to select the optimal operating condition of the system, we evaluated the removal tendencies of contaminants according to the amount of coagulant injected through lab scale test, and performed performance evaluation of the system through field test using wheel cleaning wastewater generated from the construction site. The PAC coagulant was diluted 100 times to reduce pH fluctuation. As a result, the optimal PAC injection amount was 2 ml/L. In addition, As a result of continuous operation for 10 days, SS 85.6%, turbidity 81.8%, CODcr 47.4%, TN 21.6% and TP 56.9% were removed on the average in the field test.
Recently, various types of aluminum coagulants have been developed and applied for the drinking water treatment, However, it is complicated to determine optimal coagulation conditions especially for high basicity coagulants, In order to optimize coagulation conditions (coagulant dosage and pH), conventional multifactor experiment has been applied using trial and error approach, However, there are technical limitation to optimize coagulation condition considering all factors such as coagulant dosage, p1-i, velocity gradient (0) and detention time (t). As an alternative to substitute conventional methods, the experimental design and response surface method (RSN4) in jar tests was investigated in this study. Based on the analysis of experimental results, the optimum condition considering coagulant dose, pH, velocity gradient (G) and detention time (t) was suggested for the highest removal efficiency of turbidity and UV254. The maximum removal efficiency of turbidity and UV254 resulted in pH 7 and pH 6 regardless of basicity of coagulants. The optimal velocity gradient (G) of rapid mixing for the maximum turbidity removal efficiency was 118-196 sec` and low basicity coagulants require high velocity gradient. The optimal detention time (t) of rapid mixing for the maximum turbidity removal efficiency was 67-94 sec and high basicity coagulants require short detention time. The optimal velocity gradient (G) of rapid mixing for the maximum UV254 removal efficiency of was 242-419 sec` and low basiciiy coagulants require high velocity gradient. The optimal detention time (t) of rapid mixing for the maximum UV254 removal efficiency was similar to all types of coagulants.
The objective of this research is to investigate the removal characteristics of heavy metals and sulfate ion from acid mine drainage (AMD) in a column reactor system by spherical-type porous zeolite-slag ceramics (ZS ceramics). The hydraulic retention time (HRT) condition of 24 hours in the column reactor system was found to more efficiently treat the AMD than that of 12 hours. The increment of mixing amount of converter slag in porous ZS ceramics from 1:1(Z:S) to 1:3(Z:S) was observed to enhance the removal efficiency of Cu, Cd, Mn, and Zn by 13.4%, 32.6%, 22.0%, and 48.2%, respectively. In addition, the 1:3(Z:S) porous ZS ceramics increased the alkali-supply capacity and average cycling period of back-washing relative to 1:1(Z:S) porous ZS ceramics. The average removal efficiencies of heavy metals and sulfate ion from AMD by the 1:3(Z:S) porous ZS ceramics in the column reactor under the HRT condition of 24 hours were Al 97.2%, As 98.3%, Cd 89.9%, Cu 95.5%, Fe 99.5%, Mn 76.0%, Pb 97.5%, Zn 73.2%, and SO4 2- 75.9% during 71 days of operation time. The experimental results exhibited that the porous ZS ceramics in the column reactor system could function as an efficient media for the long-term treatment of heavy metals and sulfate ion from AMD.
In this paper, highrate clarifier filtration(HCF) system is operated for tunneling wastewater with coagulant. The purpose of this study is to investigate coagulant injecting position on HCF system and characteristics of heavy metals removal for tunneling wastewater treatment. The linear velocity(LV) of HCF column 1,2 were 300m/day and 150m/day, respectively. Characteristics of tunneling wastewater is neutral pH, Turbidity is experimented from 5943 to 357NTU. And optimum dosage of aluminum sulfate was 20mg/L that used this study. As a result, Coagulant injecting to HCF column 2 was more efficient for backwash cycle, because backwash cycle was 20% long over when 20mg/L of optimal alum injecting to HCF column 2. For Al, Fe and Mn reduction, the efficiency of HCF system were 95%, 98%, 98% respectively. It tend to similar with turbidity removal of HCF system.
The focus of the former studies have been to securing appropriate pores applicable to the aquatic environment and extracting an optimum mixture which satisfies the required strength of concrete as a structure by substituting pumice stone for crushed stones used to manufacture porous concrete. However, the lack of research has been evident on the water purification performance of each optimum mixture derived from applying appropriate pores to the aquatic environment. Therefore, this study intends to compare and analyze the water purification performance of the respective optimum mixtures derived in the previous studies. According to the experimental results, it represents that the porosity or pumice stone content of porous concrete has no effect on the items of pH and DO. In the experimental results of SS, BOD, COD, T-N and T-P, their common removal efficiency was found to be higher at the design porosity of 10% than 5%. Based on the results of permeability test at the design porosity of 5%, their removal efficiency was shown to be low because continuous pores were not formed properly. By examining these issues , it is evident that if a mixture of 5-13mm crushed aggregate, 10% porosity and 10% pumice content is applied to the aquatic environment, the porous concrete can satisfy the conditions for securing appropriate pores, the required strength of concrete as a structure, and the water purification of the mixture at the same time.
Stirred dead-cell filtration has been widely used for fundamental studies on membrane fouling caused by soluble and colloidal matter during membrane filtration. In this study, the performance of MBR using a dead-end stirrer cell was conducted to investigate the removal of dissolved organic matters from real mixed liquor in aeration tank and transmembrane pressure (TMP) with hydraulic behavior on the membrane surface. Applied stirring rate as a hydraulic behavior index ranged from 100 to 1000 rpm. Influent water qualities were in the range of MLSS < 10,000 mg/L, UV<sub>254</sub> < 0.3 cm<sup>-1</sup>, dissolved organic carbon (DOC) < 45 mg/L, and specific UV absorbance (SUVA) <2.5 L/mg.m, respectively. As a result, the membrane biofiltration achieved higher efficiencies of TOC and DOC except UV<sub>254</sub> having lower efficiency < 40% regardless of the hydraulic shear force. An increase in the hydraulic shear force resulted in a decline in TMP. This indicates that higher hydraulic shear force is needed to improve TMP in operating a long-term filtration of MBR having a suitable permeate flux to enhance dissolved organic matter removal efficiency.
Application of reverse osmosis(RO) membranes is increasing due to the demand increase for the industrial water and sewage reuse recycling rate. However, it produces RO concentrate wastewater. RO concentrate is difficult to handle by conventional wastewater treatment because it contains a high concentration of non-biodegradable organics. So, it`s treatment acts as a bottleneck phenomenon of industrial water production. This study presents the Fenton-like oxidation using zero-valent iron(ZVI) as a way to handle the non-biodegradable organic material in the RO concentrate wastewater. Recently, ZVI has attention as alternative reducing agent in the way that it does not cause toxicity. The main objective of this research is to investigate the effects of a variety of factors such as pH, ZVI dose and reaction time for removal of organics in RO concentrate by Fenton-like oxidation with ZVI. All tests were proceeding under the three steps: Fenton-like oxidation, Neutralization and Sedimentation. The results show that the Fenton-like oxidation with ZVI was able to remove organics in RO concentrate. The optimal factors in Fenton-like oxidation were determined; pH 2 and 2 hours as reaction time. With this condition, the removal efficiency of chemical oxygen demand (COD) was about 37 percent at 500 mg/L as hydrogen peroxide and 750 mg/L as ZVI. Meanwhile, this study represents that the Fenton-like oxidation with ZVI has a lower organic removal efficiency than the Fenton`s oxidation. In order to achieve the same removal efficiency as Fenton`s oxidation, the Fenton-like oxidation with ZVI requires the use of more hydrogen peroxide.