铵态氮对生物过滤塔甲烷净化性能的影响及其微生物学机理

氮源是生物过滤塔高效稳定净化甲烷 (CH₄) 废气的关键因素，然而关于畜禽养殖废水中铵氮是否可以作为除CH₄生物过滤塔氮源以及相应的作用机制尚不明晰。启动并成功运行2个生物过滤塔BF_no (对照，无氮源) 和BF_A (铵态氮为氮源) ，比较分析了不同停留时间 (EBRT) 下，2个生物过滤塔的CH₄净化性能，并采用宏基因组技术解析了铵态氮影响生物过滤塔CH₄净化性能的微生物学机理。结果表明，生物过滤塔BF_A的CH₄去除性能优于生物过滤塔BF_no，当EBRT为44 min时，BF_A的CH₄去除效率稳定在80%以上，而生物过滤塔BF_no的CH₄去除效率不足70%。宏基因组分析结果表明：BF_no和BF_A具有显著不同的微生物群落结构，其中硝化螺旋菌门 (Nitrospirae) 是生物过滤塔BF_A中的特有菌属。生物过滤塔BF_A中与硝化过程相关的amoA和hao基因，以及与CH₄氧化相关的fae、mtdA和fmdA基因相对丰度均显著高于BF_no (P≤0.05) ，证明以铵态氮为氮源的生物过滤塔BF_A中不仅具有较高的硝化能力，还具有较高的CH₄氧化能力。本研究结果可为生物过滤法净化畜禽养殖含CH₄废气和液态养殖粪污的综合利用提供参考。

Effects of ammonium nitrogen on methane purification performance of biofilter and its microbiological mechanism

Nitrogen is the key factor for the efficient and stable operation of biofilters treating methane (CH4) containing gases. However, it is unclear whether the livestock wastewater with high concentrations of NH4+-N can be used as the nitrogen source of biofilter for CH4 removal and the corresponding mechanism. This study successfully operated two biofilters treating simulated CH4 containing gases, BF_no (control, no nitrogen source) and BF_A (NH4+-N as nitrogen source), and compared CH4 purification performances of the two biofilters under different empty bed residence time (EBRT). The corresponding microbiological mechanism was investigated based on metagenomic analysis. The results showed that BF_A exhibited a better CH4 purification performance in comparison with BF_no. When the EBRT was 44 min, the CH4 removal efficiency of BF_A was stable at more than 80%, while that of BF_no was less than 70%. The two biofliters had significantly different microbial community structures. The species Nitrospirae showed a quite high relative abundance in BF_A. The relative abundance of amoA and hao genes related to nitrification process, and the relative abundance of fae , mtdA and fmdA genes related to CH4 oxidation in BF_A were significantly higher than that in BF_no ( P ≤0.05), which proved that BF_A with NH4+-N as nitrogen source had higher nitrification and CH4 oxidation ability.