• 월간산업보건
• /
• s.338
• /
• pp.35-38
• /
• 2016

• 월간산업보건
• /
• s.336
• /
• pp.22-25
• /
• 2016

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.5
• /
• pp.971-980
• /
• 2000

Mixed methanotrophs (MM) secreting soluble methane monooxygenase(sMMO) were immobilized on celite R-635 to degrade trichloroethylene(TCE) in methanotrophic consortium biofilm reactor(MCBR) system. Further neutralization of celite R-635 was not needed for immobilization because effluent pH was stabilized at neutral after 4 hour washing. It took 130 days to develop biofilm on celite R-635 and the color of the celite changed gradually from white to red. After biofilm developed, influent methane and oxygen were decreased from 2.5~4 and 8~10 ppm to 0.5~1 and 1~2 ppm, respectively, With influent 2 ppm of TCE and 10 hours of retention time, 79.9% of TCE was degraded in the MCBR system.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.1B
• /
• pp.85-91
• /
• 2012

Permeable Reactive Barriers (PRBs) using zero valent iron (ZVI, $Fe^0$) is a promising technology for in-situ remediation of trichloroethylene (TCE) forming dense non aqueous phase liquid (DNAPL). The objective of this study is to develop an enhanced treatment method of trichloroethylene-contaminated groundwater using ZVI packed bed with direct current (D.C.). A column experiment was performed to investigate degradation efficiency of TCE that was performed in three different combination of control (only sand), ZVI column (ZVI:sand, packing ratio 1:2(v/v)) and bipolar column (ZVI:sand=1:2(v/v) with electric current) in the test columns. As the results of this study, the degradation efficiency of TCE was improved with simultaneous application of both bipolar column compared to that used ZVI column. Because ZVI particles are isolated and individual particles act like small electrodes. In this experiment, it was indicated a basic material for application of bipolar packed bed as electro-PRBs that was effective degradation of TCE.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.4 no.2
• /
• pp.148-156
• /
• 1994

Chloral hydrate(CH), an intermediate metabolite of trichloroethylene(TRI) is reduced to trichloroethanol(TCE-OH), and is oxidized to trichloroacetic acid(TCA) by the nicotinamide adenine dinucleotide(NAD)-dependent enzymes such as alcohol dehydrogenase(ADH) and aldehyde dehydrogenase(ALDH) in liver. This study was performed to find out the change of activity of ADH and ALDH with increasing amount of TRI. Intraperitoneal injection of TRI were done to the male Sprague Dawely rats(mean body weight, $170{\pm}10g$) in com oil at the dosage of 150, 300, 600 mg/kg for 2 days. The results of experiments are following : 1. The contents of xenobiotic metabolic enzymes in liver are tended to be decreased with increasing amount of, but not significantlly (p>0.05). 2. Activity of ADH in microsome is decreased(p<0.05), and activity of ALDH is increased with amount of TRI(P<0.05). 3. Total trichloro-compounds(TTC) concentration in urine are increased with amount of TRI, but the ratio of between the TCE-OH and the TCA were not shown any critical change. These results suggests that the ALDH in microsome may be related to metabolism of TRI, but ADH was nothing less than the effected to metabolism of TRI.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.1
• /
• pp.34-39
• /
• 2005

Trichloroethylene (TCE) is an environmental contaminant provoking genetic mutation and damages to liver and central nerve system even at low concentrations. A practical scheme is reported using toluene as a primary substrate to revitalize the biofilter column for an extended period of TCE degradation. The rate of trichloroethylene (TCE) degradation by Pseudomonas putida F1 at $25^{\circ}C$ decreased exponentially with time, without toluene feeding to a biofilter column ($11\;cm\;I.D.{\times}95\;cm$ height). The rate of decrease was 2.5 times faster at a TCE concentration of $970\;{\mu}g/L$ compared to a TCE concentration of $110\;{\mu}g/L$. The TCE itself was not toxic to the cells, but the metabolic intermediates of the TCE degradation were apparently responsible for the decrease in the TCE degradation rate. A short-term (2 h) supply of toluene ($2,200\;{\mu}g/L$) at an empty bed residence time (EBRT) of 6.4 min recovered the relative column activity by $43\%$ when the TCE removal efficiency at the time of toluene feeding was $58\%$. The recovery of the TCE removal efficiency increased at higher incoming toluene concentrations and longer toluene supply durations according to the Monod type of kinetic expressions. A longer duration ($1.4{\sim}2.4$ times) of toluene supply increased the recovery of the TCE removal efficiency by $20\%$ for the same toluene load.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.1 s.49
• /
• pp.141-152
• /
• 1995

This study was performed to find out the influences of ethanol on the metabolism of trichloroethylene(TRI) in rats. TRI in corn oil at the dosage of 150, 300, 600 mg/kg was injected peritoneally once a day for two days to two groups. In one group ethanol(4 g/kg) was taken orally 30 minutes before TRI injection, and the other group ethanol was not. The results of experiments are as follows: 1. The contents of cytochrome P-450 and $b_5$ had inverse relationship with in-jected TRI amounts in both groups. 2. The activity of NADPH P-450 reductase was decreased slowly in TRI injected group related with TRI amount, but decreased drastically in the group pretreated with ethanol. 3. The activity of NADH $b_5$ reductase had relationship with injected nt amount , but the statistical significance was found only in the groups of 300 and 600 mg/kg of TRI injected without relevance to ethanol when compared with the group that was not injected. 4. The activity of ADH was more decreased and ALDH activity was more increased in groups that TRI injected and ethanol was pretreated with ethanol groups than in group without any treatment. These results suggest that ethanol may inhibit epoxide formulation, the first step of TRI metabolism, and change from TCE-OH to TCA also.

• Journal of Life Science
• /
• v.13 no.6
• /
• pp.970-975
• /
• 2003

Microbial trichloroethylene (TCE) degradation using trickling biofilter (TBF) is a cost-effective treatment method, in which monooxygenase (MO) fortuitously transforms TCE via cometabolism. Simple TBF, however, could not be stably operated for long-term treatment of TCE due to the contradictory characteristics of cometabolism. In this paper, microbial biocatalyst and biofilm reactor system, a two-stage continuous stirred tank reactor (CSTR)/TBF system using Burkholderia cepacia G4 and Methylosinus trichosporium OB3b, are evaluated for the long-term continuous treatment of TCE. The maximum TCE elimination capacities were in the range of 28 and 525 mg TCE/1$.$day. The reactor systems were stably operated for more than 3∼12 months.

• Korean Journal of Microbiology
• /
• v.41 no.4
• /
• pp.281-286
• /
• 2005

In this study, the anaerobic enrichment cultivation was performed with the sediments and the dredged soils from the cities of Ulsan, Masan, Yeosu, Gwangyang, Ansan and Seongnam. Acetate as an electron donor and PCE (perchloroethylene) or TCE (trichloroethylene) as an electron acceptor were injected into the serum bottle with an anaerobic medium. After the incubation of 12 weeks, the removal efficiency of PCE was highest at $70\%$ in the treatment with the sediment of Ulsan. Also, the bacterial community structure was analyzed by D-DGGE (double denatured gradient gel electrophoresis) through PCR-based 16S rDNA approaches. The dominant species id the anaerobic enrichment were found to belong to the genus of Desulfovibrio.

• KSBB Journal
• /
• v.13 no.5
• /
• pp.483-490
• /
• 1998

Two unidentified methanotrophic strains (MM-white and MM-red) secreting soluble methane monooxygenase (sMMO) involved in thrichloroethylene biodegradation have been isolated from mixed methanotrophic consortium (MM) around Taejon area. Subsequently four methanotrophic strains were isolated from MM and named according to their color; white (MS-white), yellow (MS-yellow), pink (MS-pink) and reddish brown (MS-rbrown). All strains except MS-yellow which can take glucose as well as methane, metabolized methane as a sole carbon source. They all showed symbiotic behavior when methane was used as the sole carbon source. Optimum conditions of cell growth for MM were pH of 6.8 - 7.2, temperature of 29 - 32$^{\circ}C$, and gas flow rate of 6 (for methane), 40 (for air), and 4 ml/min (for carbon dioxide). The sMMO activity was expressed as naphthalene oxidation rate (${\mu}$mol/ mg protein/ hr). The sMMO activity for MM grown in flask culture with 1 ${\mu}$M of CuSO4 was 36, while it was 61 without copper. The activity for MM grown in the fermentor without CuSO4 was 1077, but is was 197 after reaction with 5 ppm of TCE. The methanotrophs showed significantly high sMMO activity despite the presence of 1 ${\mu}$M of CuSO4, although most of other strains already known could not express sMMO activity under this condition.