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Huang, Chin Yi
|關鍵字:||tetrachloroethylene;四氯乙烯;heat pre-treatment;spore-formed bacteria;dechlorination;熱篩法;產胞菌;脫氯作用||出版社:||環境工程學系||摘要:||
本實驗主要研究目的，在利用熱篩法將非產胞菌的甲烷菌篩除，探討產胞菌在四氯乙烯厭氧脫氯的過程中所扮演的角色。實驗結果顯示，產胞菌族群除了具有脫氯能力，相較於甲烷菌有較高之四氯乙烯轉換率。且由氫氣添加實驗發現，氫氣的添加有助於脫氯的進行。在有其它基質的存在下，氫氣濃度由0增加至5000 ppmV時，四氯乙烯的初始代謝速率也由2.51 nmol/day增加至3.56 nmol/day，而無其它基質存在下，氫氣濃度由0增加至5000 ppmV時，四氯乙烯的初始代謝速率也由0.81 nmol/day增加至2.68 nmol/day。
由抑制劑實驗中發現，未經前處理的實驗組，當BES添加濃度由10 mM增加至50mM時，甲烷生成量及四氯乙烯的降解能力也隨之降低，而當BES濃度大於100 mM的條件下，脫氯作用不但沒有被抑制，反而在實驗後期有較高之脫氯能力，顯示出微生物族群中除了甲烷菌，可能有其它族群也參與了脫氯的過程。而由熱篩處理後添加BES抑制劑的實驗結果可知，無甲烷生成的狀況下，隨著BES濃度的增加，四氯乙烯的脫氯不但未被抑制，乙烯的生成反而隨之增加。當BES濃度高達100 mM時，可發現乙烯生成並未隨著BES濃度的增加而增加，反而造成二氯乙烯的累積，因此BES抑制劑除了可抑制甲烷菌，可能也存在某些機制，抑制了產胞菌族群脫氯。
In this study, heat pre-treatment was used to sieve non-sporing methanogens and then to confer the spore-formed bacteria to anaerobically dechlorinate tetrachloroethylene (PCE). From experimental results, the dechlorination of spore-formed bacteria was superior to non-sporing methanogens. With the addition of hydrogen, it was found that an additive of hydrogen is helpful to enhance the dechlorination. When the concentration of hydrogen increased form 0 to 5000 ppmV, the initial PCE removal rate increased from 0.81 to 2.68 nmole/day.
Comparison with pretreatment and non-pretreatment, different inhibiting phenomena were observed under different BES concentrations. If pretreatment was not proceeded, the dechlorination of PCE was inhibited. When BES concentration increased from 10 to 50 mM, both the methane production and the PCE conversion ratio decreased. On the contrary, when BES concentration was controlled above 100 mM, the dechlorination efficiency was not inhibited, it even raised in a later experimental stage.
If pretreatment was proceeded, the PCE dechlorination was not inhibited. When BES concentration increased, the PCE dechlorinaion was not only inhibited but also caused an increase in the ethylene production. On the contrary, when BES concentration was controlled above 100 mM, the ethylene production was not only increased with BES concentrations but also caused the accumulation of dichloroethylene.
|Appears in Collections:||環境工程學系所|
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