不同碳源中硫酸盐还原菌生长状况及对砷、锑去除效率研究

A Study on the Growth State of Sulfate-reducing Bacteria and Removal Efficiency of Arsenic and Antimony in Culture Media with Different Carbon Sources

分别以乳酸、乙醇、糖蜜和米酒作为碳源,研究硫酸盐还原菌在不同碳源中的生长状况及对As和Sb的去除效率。硫酸盐还原菌接种到各碳源培养基后14 d的生长状况显示,硫酸盐还原菌在乳酸中生理活性最佳,在乙醇中也有明显的生理活性,但需要一个较长的启动期,而在糖蜜和米酒中没有明显的生理活性。当硫酸盐还原菌接种到各碳源培养12 h后加入酸性As（V）和Sb（V）储备液,由于12 h内尚未生成足够的碱度和硫化物来应对酸性储备液冲击,硫酸盐还原菌在所有碳源中均失去生理活性;虽然硫酸盐还原菌已失活且基质中只含有少量硫化物（≤3.62 mg/L）,乳酸培养基中总锑和总砷的去除率仍可达到89.7%和65.6%,糖蜜和米酒培养基中总锑去除率达到81.2%和97.3%、总砷去除率为10.0%和17.1%,不过乙醇培养基中砷和锑均没有明显的去除。后以能显著促进硫酸盐还原菌生长的乳酸和乙醇作为碳源,调节培养基初始p H约为7,并接种培养48 h后加入酸性As（V）和Sb（V）储备液,储备液加入前乳酸和乙醇培养基的硫化物质量浓度分别达到70.73 mg/L和18.58 mg/L,储备液加入后细菌仍能继续生长,最终总锑去除率可达97.8%和98.4%,总砷去除率则为27.8%和24.6%。实验结果表明,糖蜜和米酒作为碳源需进一步优化,乙醇则体现出了可替代乳酸的潜在优势;砷和锑的去除效率除了与硫酸盐还原菌活性有关外,也与砷、锑自身的化学性质及反应基质有密切关系。

The growth state of sulfate-reducing bacteria（ SRB） and the removal efficiency of arsenic and antimony by SRB were investigated,when each of sodium lactate,ethanol,molasses and vinasse was used as carbon source. Batch studies show that sulfate-reducing bacteria have the best physiological activity on sodium lactate,apparent physiological activity on ethanol but with a longer lag phase and hardly any biological activity in either molasses or vinasse media. After addition of acidic arsenic and antimony stock solutions,SRB of all media lost physiological activity because there are not enough alkalinity and sulfide produced by SRB during 12 hours to neutralize and precipitate acidic waste water. Though SRB lost physiological activity and there are minute quantities of sulfide（ ≤3. 62 mg/L） in the media,65. 6% of total As and 89. 7% of total Sb could be removed from lactate media; only 10. 0% and 17. 1% of total arsenic could be removed from the media with molasses or vinasse as carbon source but 81. 2% and 97. 3% of total Sb are removed in these media,respectively,and neither arsenic nor antimony is reduced distinctly with ethanol. Another batch test was performed that either lactate or ethanol that could apparently support SRB growth were used as carbon source and target elements stock solutions were supplemented into the media 48 hours after inoculation. The instantaneous concentrations of dissolved sulfide in the media with sodium lactate or ethanol are 70. 73 and 18. 58 mg/L before addition of arsenic and antimony,respectively. In this test,SRB could survive acidic stock solutions and finally could remove 97. 8% and 98. 4% of total antimony,27. 8% and 24. 6% of total arsenic in sodium lactate media and ethanol media,respectively. Therefore,it could be concluded that molasses and vinasse need further performance optimization and ethanol offering its potential alternative to sodium lactate as carbon source for growth of sulfate-reducing bacteria,and removal efficiency of arsenic and antimony has close connection with their own chemical property and reaction media besides physiological activity of sulfate-reducing bacteria.