• Environmental Engineering Research
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• v.16 no.2
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• pp.61-67
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• 2011

The water quality from nonpoint source run off results from different land use types has been studied. The construction of a buffer strip is one method of nonpoint source pollutant control. The Soil and Water Assessment Tool (SWAT) model has been applied to estimate the pollutant removal through the buffer strip. When the non-business land has been changed into grass to form a buffer-strip, the change of land use effects the results of the model according to measures of the water quality. The data from a water level station within the watershed in the years 2006 and 2007 was used for calibration and validation of the model. Under the rainfall conditions in 2007, the removal rates of SS, BOD, TN, TP were 11.5%, 9.5%, 1.2%, and 4.5%, respectively. During the rainy days, the removal rates at the buffer strip were 92.3% of SS, 91.2% of BOD, 82.4% of TN, and 83.5% of TP. The pollutants from nonpoint sources were effectively removed by over 80% as they passed through the buffer strips. Rainfall resulted in soil erosion, which led to an increase in the SS concentration, therefore, the construction of buffer strips protected the streams from SS inflows. Since TN concentrations are affected by the inflows of ground water and the N concentration of the rainfall, the removal rate of TN was relatively lower than for the other pollutants.

• Environmental Engineering Research
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• v.25 no.1
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• pp.36-42
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• 2020

Fenton process is one of the most effective advanced oxidation processes for the removal of pollutants from wastewater. In this study, while ferrous iron was used in conventional Fenton process (CFP); nano-sized iron(II, III) oxide was experienced in modified Fenton process (MFP) as a new catalyst alternative. In order to enhance their oxidation efficiencies, both CFP and MFP were combined with ultrasonication at 53 kHz fixed frequency. Thus, the influences of both catalyst iron species and ultrasonication on color and chemical oxygen demand (COD) removals from synthetic textile wastewater including Maxilon Red GRL 200% dyestuff were investigated experimentally. While the COD and color removal rates were found as 72.5% and 69.7% via CFP; they were 87% and 75.8% by ultrasonicated CFP, respectively. The color and COD removals were 40.6% and 64.8% via MFP, and 49.9 and 73.1% by ultrasonicated MFP, respectively. Therefore, it was found that the simultaneously usage of ultrasonication with CFP and MFP was improved the COD and color removal efficiencies and oxidation rates even at lower H₂O₂ dosages, compared to individual CFP and MFP. Moreover, the color and COD removal kinetics were also modelled mathematically and compared in the study.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.8
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• pp.1132-1140
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• 1998

The adhesion and removal of $\alpha$-Fe2O3 particles on the from PET fabric in NPE solution with different ionic strength were discussed in terms of interaction of surface charge of particle and substrate. The adhesion of $\alpha$-Fe2O3 particles to PET fabric and its removal from PET fabric were carried out by using water bath shaker and Terg-O-Tometer under various solution conditions. The ζ potential of PET fiber and $\alpha$-Fe2O3 particles in the detergent solution were measured by steaming potential and microelectrophoresis methods, respectively. The adhesion and removal amount of $\alpha$-Fe2O3 particles on the from PET fabric increased with increasing time of adhesion and removal, and the rates of adhesion and removal were high at the initial stage of adhesion and removal, and then the rates decreased with passing time. The adhesion and removal amount of $\alpha$-Fe2O3 particles on and from PET fabric increased with increasing pH of solution regardless ionic strength. The tendencies and degree of adhesion and removal were very similar regardless interaction of surface charge of particle and fiber. Therefore, in the presence of a surfactant and electrolyte, the influence of interaction of surface charge of particle and substrate on the detergency of particulate soil was small.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.625-631
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• 1999

This study was performed to determine the optimum coagulant dosing for effective treatment of raw water in Chinyang lake. Removal rates of algae and characteristics of the water according to coagulants dosage were investigated by treatment with Microcystis aeruginosa, which is a kind of blue-green algae, to the raw water below 5NTU. The coagulants dosage for maximum removal rate of algae were 30 mg/$\ell$ of Alum, 30 mg/$\ell$ of PAC and 10 mg/$\ell$ of PACS, respectively. The removal rate of algae in 30 mg/$\ell$ of PAC was highest as 85% compared with the other treatments. At the point of maximum removal rate of algae, the removal rates of turbidity were 34%, 66% and 22% in Alum, PAC and PACS, respectively. Residual Al was decreased depend upon decreasing turtidity in water by treatment of Alum or PAC, but decreased depend upon increasing turbidity in water by treatment of PACS. The removal rate of ${Mn}_{2+}$ in water was high in the order of Alum, PAC and PACS treatment. And ${Fe}_{2+}$ in water was not changed by treatemnt of these coagulants. Particle numbers distributions according to the particle size of suspended solids that were not precipitated at 8 min. of settling time after treatment of coagulants dosage for the maximum removal rate of algae were investigated. Most of the particle sizes were below 30 $\mu$m and particle numbers distributions below 10 $\mu$m were 64%, 56% and 66% by treatment of Alum, PAC and PACS, respectively. Zeta potential was in the range of -6.1~-9.7 mV at optimum coagulants dosage for algae removal.

• Membrane and Water Treatment
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• v.15 no.2
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• pp.51-57
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• 2024

The removal of phosphorus, especially phosphate-form phosphorus, is necessary in wastewater treatment. Biofouling induced by the quorum sensing mechanism is also a major problem in membrane bioreactor (MBR), which reduces membrane flux. This study introduces lanthanum-doped quorum quenching (QQ) beads into MBR, confirming their inhibitory effect on biofouling due to Rhodococcus sp. BH4 and their capacity for phosphorus removal through lanthanum adsorption. A batch test was conducted to access the phosphate adsorption of lanthanum-QQ (La-QQ) beads and lab-scale MBR to verify the effect of inhibition. The study aimed to identify distinctions among the MBR, QQ MBR, and La-QQ MBR. In the batch test, the phosphate removal rate increased as the volume of beads increased, while the unit volume removal rate of phosphate decreased. In the lab-scale MBR, the phosphate removal rates were below 20% in the control MBR and QQ MBR, whereas the La-QQ MBR achieved a phosphate removal rate of 74%. There was not much difference between the ammonia and total organic carbon (TOC) removal rates. Regarding the change in transmembrane pressure(TMP), 3.7 days were taken for the control MBR to reach critical pressure. In contrast, the QQ-MBR took 9.8 days, and the La-QQ MBR took 6.1 days, which confirms the delay in biofouling. It is expected that La-QQ can be used within MBR to design a more stable MBR process that regulates biofouling and enhances phosphate removal.

• Asian Journal of Turfgrass Science
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• v.10 no.4
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• pp.305-313
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• 1996

This study was carried out to investigate the removal rates of Cd and Pb of the litters in the Phragmites communis. Miscanthus sacchariflorus, Typha angustata, Scirpus tabernaemontani grassland aquatic ecosystem in the lake Paldangho. The annual production of Cd and Pb were 0.005g /$m^2$ , 0.21g /$m^2$in P. commumis, 0.004g /$m^2$, O.08g /$m^2$ in M. sacchariflorus, 0.023g /$m^2$, 0.42g /$m^2$ in T. angustata and 0.020g /$m^2$, 0.23g /$m^2$ in S. tabernaemontani respectively. The removal rates of Cd and Pb of the litters were 0.83, 0.85 in P. communis. 0.36, 0.54 in M. sacchariflorus, 0.61, 0.51 in T. angustata and 0.76, 0.71 in S. tabernaemontani, respectively. The times required to decay 50, 95, 99 percent of the steady state level and turnover values of cadmium on the grassland floor were 0.83, 3,60, 6.00 years in P. communis. 1.90, 8.24, 13.74 years in M.sacchariflorus, 1.15, 4.96, 8.27 years in T. angustata and 0.91, 3.95, 6.58 years in S. tabernaemontani The times required to decay 50, 95, 99 percent of the steady state level and turnover values of lead on the grassland floor were 0.81, 3.51, 5.86 years in P. communis. 1.28, 5.56, 9.26 years in M. sacchariflorus, 1.37, 5.94, 9.90 years in T. angustata and 0.97, 4.21, 7.02 years in S. tabernaemontani. Key words: Removal rate, Accumulation, Paldangho, Cadmium, Lead, Phragmites communis Miseanthus sacchariflorus, Typha angustata, Scirpus tabernaemontani.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.4
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• pp.20-27
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• 1993

Emulsified oily wastewater is generally hard to treat in separating oil and water by conventional separators. In this paper the magnetohydrodynamic water treatment device was used to separate oil from emulsified oily wastewater which contained high conductivity. The emulsified oil removal rates and economic ranges of oil separation at various factors were investigated to confirm the influence of the magnetic field in MHD water treatment device according to the characteristics of emulsion brake. Experimental results proved that the oil removal rates were proportional to Lorentz force which depends on the intensity of magnetic field, conductivity and velocity of wastewater.

• Transactions on Electrical and Electronic Materials
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• v.5 no.6
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• pp.233-236
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• 2004

Copper metallization has been used in high-speed logic ULSI devices instead of the conventional aluminum alloy metallization. One of the key issues in copper CMP is the development of slurries that can provide high removal rates. In this study, the effects of slurry chemicals and pH for slurry dispersion stability on Cu CMP process characteristics have been performed. The experiments of copper slurries containing each different alumina and colloidal silica particles were evaluated for their selectivity of copper to TaN and $SiO_{2}$ films. Furthermore, the stability of copper slurries and pH are important parameters in many industries due to problems that can arise as a result of particle settling. So, it was also observed about several variables with various pH.

• International Journal of Advanced Culture Technology
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• v.8 no.2
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• pp.283-288
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• 2020

This study investigated the purification process of groundwater contaminated with zinc and arsenic using a permeable reactive barrier with a zero-valent iron/pumice mixture. We determined the removal rates of the contaminants for 30 days. In this study, column reactor filled with the zero-valent iron/pumice reactive mixture was used. Experimental results showed that the mixture exhibited an almost complete removal of the zinc and arsenic ions. Arsenic was removed via co-precipitation and adsorption processes while zinc ions were asorbed in active sites.The purification process of water from the metal ionscontinued for 30 days with constant hydraulic conductivity because of the enhanced porosity of the pumice and interparticle distance between the zero-valent iron and pumice. Contaminants removal rates and the remediation mechanism for each reactive system are described in this paper.

• Analytical Science and Technology
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• v.37 no.1
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• pp.1-11
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• 2024

In agricultural households cultivating vegetables and fruits, the use of various pesticides to protect crops from diseases and pests or to control weeds is widely practiced enhancing quality and productivity. However, pesticides can pose a threat to consumer health by remaining on the food surface or migrating into the food interior. Households commonly peel off skins, wash with water, or use chemical methods to remove foreign substances including residual pesticides on the food surface. In this study, we measured the washing rate by comparing the pesticide concentrations before and after washing in the leafy vegetable perilla leaves and the fruits strawberries and apples, which were intentionally exposed to pesticides. We compared washing rates using tap water, a baking soda solution, and a commercially available food-specific cleaning solution. The target pesticides for analysis were azoxystrobin, bifenthrin, boscalid, difenoconazole, flubendiamide, and indoxacarb, and the residual pesticide analysis was performed using GC-MS/MS or LC-MS/MS. The removal rates of pesticides were highest with the food-specific cleaner, followed by baking soda and tap water in order.