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Kunichika Nakamiya Tohru Furuichi Kazuei Ishii 《Journal of Material Cycles and Waste Management》2002,4(2):127-134
This article reports the potential of denitrifying activated sludge to degrade highly chlorinated dioxins, especially from
a (landfill) leacheate treatment plant in Japan, and the isolation from this denitrifying activated sludge of a microorganism
able to degrade highly chlorinated dioxins. Using a 700-ml bioreactor, denitrifying activated sludge was cultivated under
denitrifying conditions by adding 2.0 ng of a mixture of 4- to 8-chlorinated dioxins from fly ash. The dioxin contents of
the sample, effluent, and medium before and after cultivation were measured by gas chromatography–mass spectrometry (GC–MS).
After 7 days cultivation, about 90% of added dioxins were lost (average percentage of isomer depletion). A dioxin-degrading
microorganism was isolated from the activated sludge. Lignin was added to the medium as a color indicator of aromatic compound
degradation, and the lignin-decolorizing microorganisms in the denitrifying activated sludge were screened. Some strains were
isolated, and one major isolated fungus, strain 622, decolorized lignin effectively. Strain 622 was identified as an Acremonium sp. from its morphological characteristics. It could decolorize lignin by 24% under paraffin-sealed anaerobic conditions.
After the cultivation of strain 622 with a 2 ng/ml mixture of 4- to 8-chlorinated dioxins for 1 day, 82% (average for individual
isomers) of the added 4- to 8-chlorinated dioxins had been degraded. Added octachlorodibenzo-p-dioxin (OCDD, 100 ng) was degraded under aerobic conditions after 8 h of incubation. During this process, heptachlorodibenzo-p-dioxin was produced and appeared to be a degradation product of OCDD. 1- or 2-hydroxydibenzo-p-dioxin from OCDD was also identified as the degradation product by GC–MS. These results indicated that OCDD was degraded
to the nonchlorinated dibenzo-p-dioxins through dechlorination by Acremonium sp. strain 622.
Received: October 12, 2001 / Accepted: March 11, 2002 相似文献
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K. Nakamiya T. Furuichi K. Ishii 《Journal of Material Cycles and Waste Management》2003,5(1):0063-0068
The optimal soil-washing conditions for dioxins were estimated on a soil sample from the circumference of an incinerator
in Nose City, Osaka, Japan. The solvents ethanol, methanol, and acetone, together with a surfactant (100% of each) could extract
40% of the dioxins from contaminated soil at room temperature. From among these solvents, ethanol was chosen for a study on
how to optimize the extraction conditions because of its low toxicity and its economic advantages. The time-course of the
agitation showed that the extraction rate increased for 1 min, and thereafter the rate decreased. Therefore, the agitation
time was fixed at 1 min. To estimate the effect of temperature on the extraction rate, the extraction temperature was changed.
The amount of dioxins extracted was largest at the boiling point of ethanol (78.3°C), giving about 76% extraction. Furthermore,
at this temperature, almost 100% of the dioxins in the contaminated soil were extracted when the ratio of water to ethanol
was 20%.
Received: March 6, 2002 / Accepted: September 9, 2002 相似文献
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Kunichika?NakamiyaEmail author Tohru?Furuichi Kazuei?Ishii Ikuo?Souda 《Journal of Material Cycles and Waste Management》2004,6(1):35-40
The degradation rate of dioxins added to the activated sludge from a leachate treatment plant of a landfill under denitrification conditions was estimated using six bioreactors. Over 99% of the added dioxins (600ng) were degraded within 7 days. Furthermore, continuous cultivation was carried out for 1 month. The activated sludge degraded 600ng of dioxins (that is, all of the added dioxins) placed in each reactor every 7 days, and this activity was maintained for 35 days. Under aerobic conditions with this sludge, the dioxins were not degraded in 7 days, but 90% of the 600ng of dioxins was degraded in 35 days. The high level of activity observed in the present study may only occur under anaerobic conditions, especially under denitrifying conditions. 相似文献
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