Bio-desulfurization and denitrification by anaerobic-anoxic process for the treatment of wastewater from flue gas washing.
Bio-desulfurization and denitrification by anaerobic-anoxic process for the treatment of wastewater from flue gas washing.
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DOI：
10.2166/wst.2013.088
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发表时间：
2013-05
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影响因子：
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通讯作者：
Ziyu Song;Xuemei Zhou;Yuguang Li;Maohua Yang;J. Xing
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文献类型：
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作者：
Ziyu Song;Xuemei Zhou;Yuguang Li;Maohua Yang;J. Xing
对于胺法CO2捕集，氮氧化物和硫氧化物是主要的污染物，对溶剂的再生有负面影响。在二氧化碳捕集之前，应先用钙盐法脱除烟气中的硫氧化物，然后用碱性溶液洗涤，以消除残留的氮氧化物和硫氧化物。含硫酸盐和硝酸盐的洗涤废水需要处理。本研究建立了一种新型的厌氧-缺氧工艺处理该洗涤废水。硝化细菌将硝酸盐还原为氮。硫酸盐首先被硫酸盐还原菌还原为硫化物，然后被硫化物氧化菌选择性氧化为元素硫。处理液经调节pH值后可作为吸收剂回用。在不同的pH值和S/N比下考察了该工艺的性能。结果表明，当进水pH值为6.0时，反硝化率和硫酸盐还原率分别可达90%和89%。76%的硫酸盐转化为元素硫。硝酸盐浓度大于10 mM时，硫酸盐还原率显著降低，当硝酸盐浓度为20 mM时，硫酸盐还原率下降到67%。结果表明，厌氧-缺氧工艺处理烟气洗涤废水是可行的。该方法对其它SO4（2-）/NO3（-）比值较高的废水具有良好的应用前景。
For amine-based carbon dioxide capture, nitrogen oxides and sulfur oxides were the main pollutants that had a negative effect on the regeneration of solvent. Before carbon dioxide capture, the sulfur oxides in flue gas should be removed by the method of calcium salt, and then washed by alkaline solution to eliminate the residual nitrogen oxides and sulfur oxides. The washing wastewater containing sulfate and nitrate needs to be treated. In this study, a novel anaerobic-anoxic process was built up for the treatment of this washing wastewater. Nitrate was reduced to nitrogen by denitrifying bacteria. Sulfate was firstly reduced to sulfide by sulfate reducing bacteria, and then selectively oxidized to element sulfur by sulfide oxidizing bacteria. The treated liquid could be reused as absorption after the adjustment of pH value. The performances of this bioprocess were investigated under various pH values and S/N ratios. It was found that the optimal pH value of influent was 6.0, the percentages of denitrification and sulfate reducing could reach 90 and 89%, respectively. Seventy-six percent of sulfate was transformed into element sulfur. Nitrate significantly had a negative effect on sulfate reduction above 10 mM. As 20 mM nitrate, the sulfate reducing percentage would drop to 67%. These results showed that the anaerobic-anoxic process was feasible for the treatment of flue gas washing wastewater. It would be prospectively applied to other wastewater with the higher ratio of SO4(2-)/NO3(-).