多壁碳纳米管长期作用对活性污泥系统的影响

为研究MWCNTs(multi-walled carbon nanotubes,多壁碳纳米管)对活性污泥长期作用的影响,建立3组(每组包括3个平行反应器)序批式活性污泥反应器,研究了2种质量浓度(1、20 mg/L)的MWCNTs长期(120 d)作用对活性污泥系统废水处理效果的影响,并采用Illumina MiSeq高通量测序技术研究MWCNTs长期作用后活性污泥中细菌群落结构的变化. 结果表明:20 mg/L的MWCNTs对生物脱氮效果存在明显的抑制作用,TN平均去除率由83.4%降至71.7%；1 mg/L的MWCNTs长期作用后TN平均去除率由83.7%降至79.7%. 1和20 mg/L的MWCNTs对磷的去除均有抑制作用,TP平均去除率分别由98.0%和98.2%降至52.0%和34.0%. Illumina MiSeq高通量测序结果表明,不同质量浓度的MWCNTs长期作用后降低了活性污泥中细菌群落的多样性. 同时,活性污泥中细菌群落结构也发生了变化,其中α-Proteobacteria和γ-Proteobacteria的丰度升高,Bacteroidetes的丰度降低. 1 mg/L的MWCNTs长期作用可致以Defluviicoccus和Micropruina为代表的一类聚糖菌(glycogen-accumulating organisms, GAOs)丰度显著升高,20 mg/L的MWCNTs长期作用可致16个核心属的丰度明显降低. 

Long-Term Effects of Multi-Walled Carbon Nanotubes on Activated Sludge System

Three groups of sequencing batch reactors (SBRs) were operated to investigate the long-term effects of multi-walled carbon nanotubes (MWCNTs) on activated sludge systems. Each group was set up in triplicate. The long-term effects of 1 and 20 m/L MWCNTs on nutrient removal of activated sludge process were investigated. In addition, bacterial community structure in activated sludge was studied using MiSeq high-throughput sequencing. It was found that 20 mg/L MWCNTs adversely affected the performance of biological nitrogen removal, which significantly reduced the average TN removal efficiencies from 83.4% to 71.7%, and average TN removal efficiencies from 83.7% to 79.7%, after long-term exposure to 1 mg/L MWCNTs. In addition, both 1 and 20 mg/L MWCNTs inhibited biological phosphorus removal, with the average TP removal efficiencies decreasing from 98.0% to 52.0% and from 98.2% to 34.0%, respectively. MiSeq sequencing indicated that 1 and 20 mg/L MWCNTs obviously decreased the diversity of bacterial community in activated sludge. MWCNTs differentially enhanced the abundance of α-Proteobacteria and γ-Proteobacteria, and reduced the abundance of Bacteroidetes. The long-term effects of 1 mg/L MWCNTs significantly enhanced the abundance of glycogen accumulating organisms (GAOs) (i.e. Defluviicoccus and Micropruina), which are thought to out-compete the polyphosphate-accumulating organisms (PAOs) in activated sludge communities removing phosphate. The long-term effects of 20 mg/L MWCNTs significantly decreased the abundance of 16 core genera.