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| Temperature Effect on and Microbial Community Structure Dynamics During In-situ Oxidation of Black and Odorous Sediment by Calcium Nitrate |
| Received:January 07, 2015 |
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| KeyWord:black and odorous sediment;calcium nitrate;temperature;microbial community structure;DGGE |
| Author Name | Affiliation | E-mail | | WANG Lin | Department of Environmental Science and Engineering, South China Agricultural University, Guangzhou 510642, China | | | ZHONG Yun-xiao | Department of Environmental Science and Engineering, South China Agricultural University, Guangzhou 510642, China | | | YU Guang-wei | Department of Environmental Science and Engineering, South China Agricultural University, Guangzhou 510642, China | yuguangwei@scau.edu.cn | | LONG Xin-xian | Department of Environmental Science and Engineering, South China Agricultural University, Guangzhou 510642, China | |
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| Abstract: |
| Black and odorous river sediment contain large amount of sulfides. Calcium nitrate is an effective agent for in-situ oxidation remediation. A simulated experiment was designed to investigate the effects of low temperatures(12 ℃ to 22 ℃) on sulfur oxidation-denitrification. Changes of microbial community structure in sediments at different stages of oxidation process were also investigated at a constant temperature of 30 ℃ using DGGE combined with clone and sequencing techniques. Results showed that an effective sulfide removal by calcium nitrate occurred during the denitrification process, and the temperature was a key factor. The removal rate of sulfide was very low at temperature lower than 15 ℃。 Calcium nitrate addition increased the microbial diversity in the treated sediment. Significant differences of microbial community structure were observed between day 0(initial untreated sediment), day 1, day 3-14(denitrification process) and day 50(calcium nitrate exhausted) of calcium nitrate addition. Sulfur-oxidizing bacterium Sulfuricurvum sp.(96% similarity) was found to be the main strain in the original sediments, whereas heterotrophic denitrifier Thermomonas sp.(99% similarity) increased with the progress of denitrification. However, the band intensity of Sulfuricurvum sp. and Thermomonas sp. became quite weak when calcium nitrate was exhausted, but Smithella sp.(97% similarity), a propionate oxidizing bacterium, gradually became the dominant species. These findings advance our understanding and application of the calcium nitrate in-situ oxidation technology. |
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