• KSBB Journal
• /
• v.15 no.4
• /
• pp.393-397
• /
• 2000

The cometaboic biodegradation conditionso f trichloroethylene(TCE) by Burkholderia cepacia G4 were optimized using response surface analysis. The experimental sets of phenol concentration temperature and pH were designed using central composite experimental design. The optimal conditions of phenol concentration temperature and pH were determined to be 0.91 ppm 21.5$^{\circ}C$ and 7.65 respectively by the Ridge analysis of the contour plot for TCE biodegradation rates. The TCE biodegradation rate could be enhanced up to 2.43 nmol.mg protein$.$min by response surface methodology.

• KSBB Journal
• /
• v.16 no.3
• /
• pp.281-285
• /
• 2001

Biofiltration of volatile organic compounds (VOCs) was performed for 80 days in a biofilter packed with peat. The empty bed residence time was 3.2 min. for a gas mixture of isoprene, dimethyl sulfide, chloroform. benzene, trichlorethylene, toluene, m0xylene, o-xylene and styrene. After 34 days of acclimatization the removal efficiency for a 83 g/㎥ gas input was 93% at $25^{circ}C$ and 73% at $45^{circ}C$, respectively. The maximum cell density at $25^{circ}C$ was 1.12$\times$10(sup)8 cells/g. Removal efficiencies of m-xylene and toluene (91%) were better than that of benzene (86%). The first quarter of the packed column removed 60% of the incoming VOCs.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.3 no.1
• /
• pp.3-13
• /
• 1993

This study was conducted at seven degreasing processes in plating plants located in Seoul, Incheon, Ansan, and Taejeon areas from July 21 to august 27, 1992. This study was performed to assess the TWA exposures to trichloroethylene (TCE) and evaluate factors affecting TCE concentrations in degreasing process. Two-Point Eddy Diffusional Model suggested by Wadden et al. was employed to calculalte emission factors according to degreaser type. Results are summarized as follows. 1. The TWA exposures of the degreasing operators ranged from 1.4 ppm to 123 ppm, and those of three plants out of seven were exceeding 50 ppm of both the Korean and U.S. OSHA standards. Degreasing assistant of Plant B, was exposed to 59 ppm. 2. The average concentrations at the distance 0, 1.5, 3.0 m from the degreasers were 1.014, 24, and 18 ppm, respectively, and showed a signifficant difference by distance (p<0.01). 3. The emission of TCE was reduced by installing local exhaust systems, condensers, and refrigeration lines at the degreasers (p<0.01). 4. The major factors related to exposure of operators were workload (r=.9621. p<0.01) and dimensions of degreansing room(r=-.8667, p<0.05). 5. If the air in degreasing room is mixed violently by other factors in addition to diffusion, the emission factors can not be evaluated because the important hypothesis of the Two-Point Eddy Diffusional Model can not be accepted. 6. The ultrasonic degreaser without the local exhaust ststem, condenser, and refrigeration lines emitted TCE three times greater than the ultrasonic degreaser with condenser and refrigeration 1ines only.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.6
• /
• pp.596-602
• /
• 1991

The comopositon of lipids extracted from corn embryo with various solvents were analyzed. The solvents for the extraction were benzene(BZ), n-hexane(HX), pet. ether(PE), trichlorethylene (TE), chloroform-methoanol(2:1, v/v) (CM), dichlormethane - methanol(2:1, v/v)(DM) and hexanediethyl ether(5:1, v/v)(HD). The lipids were than fractinated by silicis acid column chromatography(SACC) into three lipid fractions. The Neutral lipid fractons were further separated by thin layer chromatography(TLC) and the individual lipid spots were quantitatived by TLC scanner. And then the fatty acid compositions of total lipids and neutral lipids were determined by gas chromatography(GC). Crude oil contents of corn embryo were most efficient by using DM, CM and neutral lipid was extracted much HX, BZ, HD systems than did PE, DM, DM an CM were most efficient solvent systems for extracting glycolipid and phospholipid. The major component of the neutral lipid fractions was found to be triglyceride, and it was superior DM to PE. Linoleic acid was the predominant fatty acid in the total lipids, and it was most efficient with BZ and TE. The major fatty acid in neutral lipids was also linoleic acid and it was superior BZ to PE, CM, HD and oleic acid was similar to seven solvents and palmitic acid was found much superior in using CM.