微纳米气泡对小微水体中好氧微生物群落的影响

微纳米气泡越来越多地应用于小微水体的治理与生态修复,并取得了良好的效果。在相同溶解氧浓度下,探究了微纳米气泡和普通气泡两种曝气体系下水体和底泥内微生物群落结构的差异。结果表明,微纳米气泡组的溶解氧水平维持周期长于普通气泡组,微纳米气泡的缓释性和高效复氧性可使水体内的溶解氧浓度长期保持在较高水平;同时,微纳米气泡曝气对污染物降解的促进作用更优。对属水平微生物的分析结果表明,微纳米气泡曝气组的微生物几乎全部为好氧微生物,前18种微生物占比为67.90%;而普通气泡曝气组的微生物群落内好氧微生物和厌氧微生物占比无明显差异,前18种微生物占比为41.36%。微纳米气泡曝气使好氧微生物成为绝对优势菌种,显著提高了水体的可生化性,从而加速了水体内污染物的降解。在没有对底床造成直接冲击的条件下,微纳米气泡的作用范围主要在水体,短期内对底泥中的微生物群落并无显著作用。

Effect of Micro-nano Bubble Aeration on Aerobic Microbial Community in Small Water Body

The micro-nano bubble(MNB)aeration has been increasingly used in ecological restoration of small water body,and it has achieved good results.Under the same dissolved oxygen(DO)concentration condition,differences of microbial community in water and sediment aerated by micro-nano bubble aeration system and traditional macro-bubble aeration system were investigated.DO maintaining period of MNB aeration system was longer than that of macro-bubble aeration system.The slow release velocity and high transfer efficiency of MNB could keep DO concentration in the water at a high level for a long time.Meanwhile,pollutants degradation in MNB aeration system was better than that in macrobubble aeration system at the same DO concentration.Analysis of microorganisms at genus level indicated that almost all microorganisms in MNB treated water were aerobic microbes and the top 18 genera accounted for 67.90%of the microbial community.However,no significant differences between the percentage of aerobic and anaerobic microorganisms in traditional macro-bubble aeration system,and the top 18 genera accounted for 41.36%of the microbial community.Aerobic microorganisms predominated in MNB aeration system,and it significantly improved the biodegradability of the water,thereby accelerating the degradation of pollutants.Without direct impact on the sediment,the impact scope of MNB was mainly in water body,and it had no remarkable effect on microbial community in the sediment in the short term.