Combination of zero-valent iron and anaerobic microorganisms immobilized in luffa sponge for degrading 1,1,1-trichloroethane and the relevant microbial community analysis

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• 作者：Wenbing Wang ; Yanqing Wu
• 关键词：1 ; 1 ; 1 ; Trichloroethane ; Anaerobic microorganism ; Immobilization ; Co ; metabolism dechlorination ; Groundwater contamination
• 刊名：Applied Microbiology and Biotechnology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：101
• 期：2
• 页码：783-796
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Microbiology; Microbial Genetics and Genomics; Biotechnology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-0614
• 卷排序：101

文摘

1,1,1-Trichloroethane (1,1,1-TCA), a dense non-aqueous phase liquid (DNAPL), is relatively slow to remediate naturally; combination of zero-valent iron and immobilized microorganism is a potential means to accelerate DNAPL biodegradation. We first adopted high density luffa sponge (HDLS) as immobilized microorganism carrier. The experimental results demonstrated that (1) the supernatant liquid microorganisms were the optimal immobilized microorganisms for HDLS and (2) the combination of zero-valent iron and immobilized microorganisms accelerated 1,1,1-TCA transformation. Furthermore, in the long-term remediation process, anaerobic microorganisms produced reductant H₂S which was beneficial to zero-valent iron PRBs. Through further study of the microbial community, we found that majority of the sulfate-reducing bacteria (SRB) perfectly adapted to the process of 1,1,1-TCA co-metabolism dechlorination. Desulfobulbus and Desulfococcus potentially were the special SRB that contributed significantly to TCA co-metabolism. Additionally, 1,1,1-TCA induced the generation of new SRB and stimulated the growth of majority of dominating methanogens. The results indicated that they played a constructive role in accelerating the dechlorination of 1,1,1-TCA, reduction of sulfate, and improving the production of CH₄. Consequently, combination of zero-valent iron and immobilized microorganisms for remediating groundwater by contaminated 1,1,1-TCA is a sustainable and green remediation technology. Especially for groundwater of SO₄2− type contaminated by 1,1,1-TCA, in the long-term course of combination degradation, cyclic utilization of H₂S to prolong the service life of zero-valent iron PRBs. H₂ and CH₄ generated to capture as potential energy resource. Based on this, a tentative reaction mechanism for Fe0 biodegradation of 1,1,1-TCA was proposed.