三株低温硝化菌的筛选及其固定化脱氮性能

由于季节、地域等因素导致的低温环境会严重影响污水生物处理系统中微生物活性,如何提高微生物在低温废水中的脱氮效果是亟待解决的问题。从工程实际出发,在3种不同环境中提取出低温硝化菌BC-15、SL-14、MI-11,其在13℃下仍具有高效的脱氮性能,经16S rDNA鉴定均为Acinetobacter sp.。菌株间不产生拮抗反应,BC-15、SL-14、MI-11最佳复配体积比为1∶1∶1。采用海藻酸钠-聚乙烯醇和海藻酸钠-硅藻土材料对复配菌株包埋固定化,对比结果表明海藻酸钠-硅藻土材料固定化硝化能力更强,优化固定化材料最佳配比为硅藻土1%、SA 2%、CaCl₂ 3%、沸石6%。固定化颗粒成球性、传质性、稳定性均较好,固定后菌株耐酸耐碱能力明显增强,重复利用4次后氨氮去除率仍可达到76.67%,硝化能力和结构稳定。固定化颗粒对实际生活污水中的氨氮去除率可达到95.86%,具有高效的硝化能力,为低温污水处理实际工程应用提供了可能。

THE SCREENING OF LOW-TEMPERATURE NITRIFYING BACTERIA STAINS AND THEIR IMMOBILIZATION AND DENITRIFICATION PERFORMANCE

Low-temperature environment is usually inevitable for the sewage biological treatment system, which seriously affects the microbial activity. How to improve the denitrification effect of microorganisms in low-temperature is an urgent problem. In this study, low-temperature nitrifying bacteria BC-15, SL-14 and MI-11, extracted from three different environments all had high nitrogen removal efficiency at 13 ℃, and all of them were identified as Acinetobacter sp. by 16S rDNA. There was no antagonistic reaction among the strains, and the best compound ratio was 1∶1∶1. Compared with sodium alginate-polyvinyl alcohol and sodium alginate-diatomite materials, the results showed that sodium alginate-diatomite materials had stronger immobilization and nitrification ability, and the best ratio of immobilization materials was 1% diatomite, 2% SA, 3% CaCl₂ and 6% zeolite. The spheroidization, mass transfer and stability of the immobilized particles were all reliable. After immobilization, the acid and alkali tolerance of the strain was significantly enhanced, and the removal rate of ammonia nitrogen still reached 76.67% after 4 times of reuse, and the nitrification ability and structure were stable. The removal rate of ammonia nitrogen in real domestic sewage by immobilized particles reached 95.86%, showed high nitrification ability, and could raise the possibility for the practical engineering application of low temperature sewage treatment.