氧调控下人工湿地微生物群落结构变化研究

运用磷脂脂肪酸(PLFAs)技术研究了氧调控下复合垂直流人工湿地(IVCW)微生物群落结构及活性变化,结果表明,不曝气IVCW基质表层以好氧微生物为优势种群,但绝大部分微生物都集中在0～20cm基质层,系统的净化空间受到限制;氧调控下微生物群落向基质纵深发展,表征好氧微生物的单不饱和脂肪酸的含量显著增加,曝气系统下行池表层各类群微生物的生物量为不曝气系统的2～6倍,表征微生物活性的PLFAs总不饱和度水平也明显升高;革兰氏阴性细菌成为曝气IVCW基质微生物群落的优势种群,群落具有更高的活性和专一性,提高了污染物的去除效果。因此,进一步研究微生物的这种适应机制可以为优化湿地系统提供一定的理论基础。

Changes in Microbial Community Structure in Constructed Wetland Under Aeration Condition

Many previous results have shown that there is an improvement of ammonia removal while oxygen level inside wetland is enhanced.However,it remained unclear whether artificial aeration could improve the purification efficiency of constructed wetland and how the redox environment influence microbial community structure.Thus,changes in microbial community structure and activities in integrated vertical-flow constructed wetland(IVCW)under aeration condition were studied.The results showed that the aerobic microorganisms were the predominant group among the microbial community in surface substrate of non-aerated IVCW,but the most majority of microorganisms were concentrated in the 0～20 cm substrate layer,indicating that purifying efficiency of the system was limited.Artificial aeration enhanced growth of microbial community into depth,as well as significantly increased in microbial biomass and activity.The characteristic monounsaturated fatty acids of aerobic microorganisms were obviously increased,and the surface substrate microbial biomass in down-flow chamber of aerated system was 2 to 6 times of non-aerated system.The unsaturation degree of total phospholipid fatty acids(PLFAs)significantly increased,indicating that microbial activity also enhanced.The gram-negative bacterial became the predominant group among the microbial community,so that it had a higher activity and improved pollutants removal.Therefore,further study of microbial adaptation mechanism can provide a theoretical basis for optimizing constructed wetland system.