Li Hui-Ting, Cui Fu-Yi
School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Huan Jing Ke Xue. 2017 Dec 8;38(12):5229-5236. doi: 10.13227/j.hjkx.201706001.
In the present study, the fate and long-term effect of TiO nanoparticles (NPs) on anaerobic granular sludge (AGS) was evaluated in an anaerobic methanogenic system. In the short-term experiment, the methane production rate decreased when the dosage of TiO NPs was greater than 150 mg·g. However, no significant difference in the products of acidification and methanation between the control and 150 mg·g(as VSS) of TiO NPs assays was observed, indicating low bacteria cytotoxicity of TiO NPs on AGS in dark anaerobic digestion. The operation data of the AGS bioreactor showed that acidogens was more sensitive to prolonged exposure to TiO NPs with the accumulation of VFAs and a decrease of biogas production in the TiO NPs containing reactor. The inhibiting effect of TiO NPs on the AGS might be attributed to the physical restraints. The average TiO concentration escaping with the effluent was 0.632 mg·L, suggesting most of the NPs were retained inside the reactor. The long-term presence of TiO NPs could alter the composition of the microbial communities in the AGS, since the amount of a increased by 115.6%. The results also indicated that the treatment of short-term sudden exposure to TiO NPs using batch tests might not be appropriate for interpreting their cumulative effects on the AGS, since a long time was need for the TiO NPs to show negative effects on the microbial populations in the AGS. Our study could supply useful proof for assessments of potential risks for TiO NPs on anaerobic activated sludge.
在本研究中，在厌氧产甲烷系统中评估了二氧化钛纳米颗粒（NPs）对厌氧颗粒污泥（AGS）的归宿和长期影响。在短期实验中，当二氧化钛纳米颗粒的剂量大于150mg·g时，甲烷产生速率下降。然而，在对照和150mg·g（以挥发性悬浮固体计）的二氧化钛纳米颗粒试验之间，未观察到酸化和甲烷化产物有显著差异，这表明在黑暗厌氧消化中二氧化钛纳米颗粒对厌氧颗粒污泥的细菌细胞毒性较低。厌氧颗粒污泥生物反应器的运行数据表明，产酸菌对长期暴露于二氧化钛纳米颗粒更为敏感，在含有二氧化钛纳米颗粒的反应器中，挥发性脂肪酸积累且沼气产量下降。二氧化钛纳米颗粒对厌氧颗粒污泥的抑制作用可能归因于物理限制。随流出物逸出的二氧化钛平均浓度为0.632mg·L，这表明大多数纳米颗粒保留在反应器内。二氧化钛纳米颗粒的长期存在可能会改变厌氧颗粒污泥中微生物群落的组成，因为某一种群的数量增加了115.6%。结果还表明，使用批次试验处理短期突然暴露于二氧化钛纳米颗粒的情况可能不适用于解释它们对厌氧颗粒污泥的累积影响，因为二氧化钛纳米颗粒需要很长时间才会对厌氧颗粒污泥中的微生物种群产生负面影响。我们的研究可为评估二氧化钛纳米颗粒对厌氧活性污泥的潜在风险提供有用的证据。
