纳米Fe3O4短期与长期接触下对活性污泥特性的影响

通过短期与长期接触实验,探讨了纳米Fe3O4颗粒(Fe3O4 NPs)对于活性污泥除污效能、松散型胞外聚合物(LB-EPS)和紧密型胞外聚合物(TB-EPS)组分的影响,并利用高通量测序技术对活性污泥中微生物群落结构的变化进行了分析。结果表明:(1)短期接触实验中,投加Fe3O4 NPs的实验组COD去除率(81.56%)低于未投加Fe3O4 NPs的对照组(84.01%),氨氮去除率(53.98%)低于对照组(55.16%);但在LB-EPS与TB-EPS三维荧光光谱(EEM)中,均出现了色氨酸类与芳香族蛋白荧光峰。(2)长期接触实验中,实验组的平均COD去除率为91.67%,略高于对照组(90.75%),平均氨氮去除率(98.26%)与对照组(98.35%)相差不大。Fe3O4 NPs的投加对于活性污泥去除污染物方面并没有明显抑制,且脱氢酶含量提高。(3)长期接触实验后,拟杆菌门(Bacteroidetes)相对丰度从29.05%降至26.25%;浮霉菌门(Planctomycetes)相对丰度从11.83%增加到16.76%。

Short-and long-term exposure effects of Fe3O4 nanoparticles on activated sludge

With the short-and long-term exposure experiments,the effect of Fe3O4 nanoparticles(Fe3O4 NPs)on the performance,the contents of loosely bound extracellular polymer substrates(LB-EPS)and tightly bound extracellular polymer substrates(TB-EPS)of activated sludge were studied.Meanwhile,the microbial community dynamics in the activated sludge was investigated by high throughput sequencing technology.Results showed that:(1)during the short-term exposure experiments,the COD removal rate of the experimental reactor with addition Fe3O4 NPs was 81.56%,lower than that of the control group reactor(84.01%),and the ammonia nitrogen removal rate(53.98%)was lower than that of the control group reactor(55.16%).After short-term exposure experiments,the peaks of tryptophan protein-like and aromatic protein in the excitation-emission matrix(EEM)fluorescence spectra appeared in the LB-EPS and TB-EPS extracted from activate sludge samples.(2)During the long-term exposure experiments,the average COD removal rate of the experimental reactor was 91.67%,slightly higher than that of the control group reactor(90.75%),and the average ammonia nitrogen removal rate(98.26%)was not significantly different from that of the control group reactor(98.35%).It was showed that the effect of Fe3O4 NPs on the removal of pollutants was not significantly and the activity of dehydrogenases was improved in the experimental reactor.(3)After long-term exposure experiments,the abundance of Bacteroidetes reduced from 29.05% to 26.25%.However,the abundance of Planctomycetes increased from 11.83%to 16.76%.