氧含量对嗜热膜生物反应器烟气脱硝脱汞的影响

Effect of oxygen concentration on simultaneous removal of NO and Hg^0 in a thermophilic membrane bioreactor

基于嗜热生物法构建膜生物反应器实现烟气中NO和Hg^0高效处理,研究氧含量对嗜热膜生物反应器烟气脱硝脱汞性能及微生物群落结构的影响。结果表明:氧含量为2%、6%和10%时,NO去除率均稳定在80%,氧含量为17%时氧促进NO降解,NO去除率达91.0%;Hg^0去除率随氧含量的增加而升高,氧含量为17%时,Hg^0去除率可达92.0%。氧含量的增加促进氨氮的降解,且有利于硝化反应的进行。缺氧和厌氧环境有利于减少膜污染,FT-IR结果表明氧含量影响EPS中官能团含量和成分。16S rDNA结果表明氧含量10%中好氧反硝化菌占比重最高。Zobellella、Paracoccus、Bacillus、Alcaligenes、Arthrobacter、Acinetobacter、Pseudomonas均为好氧反硝化菌。

A membrane bioreactor was constructed based on thermophilic biological method to achieve efficient treatment of NO and Hg0 in flue gas. In the present study, effects of oxygen concentration on simultaneous denitration and demercuration performance, and microbial community in thermophilic membrane bioreactor （TMBR） have been evaluated. All the removal efficiencies of NO approached 80% when oxygen concentration was 2%, 6% and 10%, whereas the removal efficiency of Hg0 was gradually enhanced with the increase of oxygen concentration. Under oxygen concentration of 17%, the removal of NO and Hg0 in TMBR presented the highest efficiencies among four typical oxygen concentrations, which were up to 91.0% for NO removal and 92.0% for Hg0 removal, respectively. Results suggest that the increased oxygen concentration could facilitate the ammonia nitrogen degradation, which was beneficial to the nitrification. Anaerobic and anoxic environment may mitigate membrane fouling. FT-IR results indicate that oxygen concentration affected the concentration and composition of functional groups of EPS. According to analysis results of microbial community in TMBR using 16S rDNA technique, the abundance of aerobic denitrifying bacteria was the highest in TMBR at 10% oxygen concentration. Moreover, Zobellella, Paracoccus, Bacillus, Alcaligenes, Arthrobacter, Acinetobacter, Pseudomonas were aerobic denitrifying bacteria.