• Environmental Engineering Research
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• v.14 no.2
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• pp.126-133
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• 2009

This study investigated the removal characteristics of various micro organic compounds by low-pressure nanofiltration membranes comprised of disinfection by products and pharmaceutically active compounds. The experimental removal of micro organic compounds by low-pressure nanofiltration membranes was compared with the transport model calculations, which consist of diffusion and convection terms including steric hindrance factor. The selected molecule from the disinfection byproducts and pharmaceutical active compounds showed a much lower removal than polysac-charides with a similar molecular size. However,the difference between model calculation and experimental removal of disinfection by-products and pharmaceutically active compounds could be corrected. The correlation of Ks with solute radius was further considered to clarity transport phenomena of micro organic solutes through nanofiltration membranes.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.3
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• pp.91-100
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• 1999

Treatment conditions of DAF(Dissolved Air Flotation) and removal rates of VOCs(Volatile Organic Compounds) in mixed water of H raw water and VOCs were investigated. The used VOCs were benzene, toluene, ethylbenzene, and xylene in aromatic compounds and iso propyl mereaptan, n-butyl mereaptan, dimethyl disulfide, and iso butyl mercaptan in odors. The related parameters include water type, treatment method, clay concentration, pH condition, flocculation time, flotation time, per-cent recycle, water temperature, pressure. The removal rates of VOCs were different on treatment process and water condition. Treatment time was longer, removal rates of VOCs was higher. Water temperature was more important than pressure in DAF parameters. Molecular weight was related with removal rate in several kinds of VOCs were decraesed by competition of each component in II raw water. When algac blooming D water was treated by DAF, TCOD(Total chemical Oxygen Demand) and chorophyll a was removed over 96%.

• Journal of Environmental Science International
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• v.17 no.11
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• pp.1265-1271
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• 2008

Aerated submerged bio-film (ASBF) pilot plant has been developed. The presented studies optimized an inexpensive method of enhanced wastewater treatment. The objectives of this research were to describe pilot scale experiments for efficient removal of dissolved organic and nitrogen compounds by using ASBF reactor in plug-flow reactor (PFR) and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophs and autotrophs in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. This direct gas-phase contact should increase the oxygen transfer rate into the bio-film, as well as increase the micro-climate mixing of water, nutrients, and waste products into and out of the bio-film. This research also investigated the efficiency of dissolved organic matter and ammonia nitrogen removals in the ASBF. As it was anticipated, nitrification activity was highest during periods when the flow rate was lower, but it seemed to decline during times when the flow rate was highest. And ammonia nitrogen removal rates were more sensitive than dissolved organic matter removal rates when flow rates exceeded 2.2 L/min.

• KSBB Journal
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• v.27 no.3
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• pp.145-150
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• 2012

This study was accomplished using packed bed column reactors that contain nonsurface-modified polypropylene media and surface-modified media from hydrophobic surface property into hydrophilic property by ion beam irradiation. The objectives of this research was investigated the characteristics of organic compounds removal and microbe attachment from sewage of school cafeteria in these reactors. In 736.8 mg/L of the average inflow $COD_{Cr}$ concentration the reactors with and without surface modification showed 81.8% and 70.3% of average $COD_{Cr}$ removal efficiencies, respectively, which proves the $COD_{Cr}$ removal efficiency of surface-modified media reactor is higher than that of nonsurface-modified media reactor. After 90 days, there were maximum differences between modified system and non-modified system. In that time the maximum removal efficiency of $COD_{Cr}$ was 96.5% in modified system and was 85.2% in non-modified system that showed removal efficiency of surface-modified media system is 11.3% higher than that of nonsurface-modified media system. The average removal efficiency of SS was 80.4% for the surface modified system and 61.6% for the non-modified system under same condition. Also, the reactor of surface-modified media has advantage on microbe attachment and biofilm formation.

• Journal of Environmental Science International
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• v.8 no.6
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• pp.699-704
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• 1999

The Photodegradation efficient of total organic compounds in the drinking water has been studied using the methods of photocatalytic reaction and laser beam irradation. The results are summarized as follows; 1. The photodegradation efficiency of total organic compounds shows as $50\%\;to\;80\%$ as within one hour and after this the efficiency is decreased slowly. 2. The photodegradation efficiency of total organic compounds shows as 65 to $90\%$ within 3.3min. when Nd : YAG beam is irradiated to the water layer. 3. An excellent observation of the organic compound removal efficiency gives revealed in that case of the longest wavelength of 532nm is irradiated among the three kinds of laser beam sources of 532nm, 355nm and 266nm. 4. The organic compound removal efficiency shows high in the case of UV beam irradiation in the thin layer of water. However the efficiency is not depended on the thickness of water layer severely. 5. The removal efficiency of the organic compounds in the direct irradiation shows higher than the indirect irradiation in the case of UV beam, but the efficiency is not depended on the direction of irradiation in the case of Nd : YAG beam irradiation.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.101-114
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• 1998

Soil vapor extraction (SVE) is known to be an effective process to remove the contaminants from the soils by enhancing the vaporization of organic compounds using forced vapor flows or applying vacuum through soils. Experiments are carried out to investigate the effects of the organic contaminants, types of soils, and water contents on the removal efficiency with operating time. In the study, simulated soils include the glass bead which has no micropore, sand and molecular sieve which has a large volume of micropores. As model organic pollutants, toluene, methyl ethyl ketone, and trichloroethylene are selected. Desorption experiments are conducted by flowing nitrogen gas. Under the experimental conditions, it is found that there are linear relationships between logarithm of removal efficiency and logarithm of number of pore volumes. The number of pore volumes are defined as the total amount of air flow through the soil column divided by the pore volume of soil column. For three organic compounds studied, the removal rate is slow for no water content, while the number of pore volumes for removal of organic compounds are notably reduced for water contents up to 37%. For the removal of dense organic compound, such as trichloroethylene, a large number of pore volumes are needed. Also, the effects of the characteristics of simulated soils on the removal efficiency of organic compounds are studied. After the characterization of soil surface, porosity of soil columns and types of contaminants, the results could provide a basis for the design of SVE process.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.289-297
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• 2004

Emissions of volatile organic compounds and odors from various industrial processes not only pollute surrounding life environments, but also lead to the deterioration of the working environments, causing various industrial health and business problems. These pollutants are usually stimulating, irritating, malodorous and sometimes carcinogenic, Which should be reduced in the pollutants formation, stage, but the practical processes do not allow This paper describes the major sources of VOC and odors, and their sampling/analysis methods. Furthermore, various removal technologies for these pollutants are suggested, which particularly include the characteristics of the catalytic and scrubber/carbon filter combined process, and even process design technologies.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.926-932
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• 2006

A series of bench-scale membrane filtration experiments were performed to systematically investigate the removal mechanisms of reverse osmosis (RO) and nanofiltration (NF) membranes for BTEX (benzene, toluene, ethylene, xylene), trichloroethylene (TCE) and tetrachloroethylene (PCE). The molecular weight of these organic compounds ranged from 78 to 166 dalton. The rejection of organic compounds by RO/NF membranes varied significantly from 59.6 to 99.2% depending on solute and membrane types. Specifically, experimental results demonstrated that the removal efficiency of RO/NF membranes increased as solute molecular characteristics such as W/L (molecular width/length) ${\times}$ $M_W$ (molecular weight) and octanol-water partition coefficient increased. This observation suggested that the rejection of small organic compounds by RO/NF membranes was determined by the combined effect of physical (molecular size and shape) and chemical (hydrophobicity) properties.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.69-72
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• 2003

Volatile organic compounds (VOC) cause air pollution problem and deterioration of atmosphere of petrochemical and fine chemical plants. Hybrid process of membrane and cold-condensation were developed and it effectively removed and recycled the VOC. Operation parameters of the process were optimized to attain hish removal and recycle of VOC. Composite membranes for organic vapor separation were developed in this work by PDMS coating and plasma polymerization on polypropylene and polysulfone support membranes. PDMS and various silicone monomers were tested for several organic vapors such as benzene, toluene, TCE, and HCFC, which are produced in petrochemical and fine chemical industry and causes air pollution problems if are released to atmosphere. Composite membranes prepared in this work showed appreciable performance in terms of organic vapor removal and reuse. Performance variation of the membranes was correlated with their surface characteristics.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.58-61
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• 2002

An alternative to pump and treat groundwater remediation is the use of reactive barriers. Zero valent iron (ZVI) is particularly useful as a reductant of chlorinated hydrocarbons because of its low cost and lack of toxicity ZVI can drive the dechlorination of chlorinated organic compounds and the reduction of chromium from the Cr(Ⅵ) to the Cr(III) state. The contaminants in subsurface environment usually exist as the mixed compounds. Therefore, the objective of this research is to study the effect of the other compounds on TCE removal by ZVI. The removal mechanism of TCE by ZVI is separated the dechlorination and sorption. TCE removal by ZVI slightly increased in presence of naphthalene as the non-reduced compound. TCE removal by ZVI remarkable decreased in presence of carbon tetrachloride, nitrate, and chromate as the reduced compounds. This research suggests that the effect of the coexisted compounds on the removal chlorinated compounds by reactive barrier technology should be considered for practical application.