氧化铈纳米颗粒对活性污泥系统的影响

发布时间：2019-07-04 14:57

【摘要】：近年来,纳米材料(NMs)因其特殊优异的物理化学性质而被广泛应用在人类生产生活中的方方面面。大量生产和使用NMs将难以避免地导致其在水环境中的释放。目前,NMs对人体和其它生物的潜在风险得到学者广泛关注,但是关于它对污水生物处理工艺可能带来的风险研究还较为缺乏。本文选取当前极具市场前景之一的氧化铈纳米颗粒(CeO2 NPs),研究它对活性污泥系统(ASS)急性和慢性作用后,出水水质和ASS中微生物群落结构的变化,得到结论如下：1.CeO2 NPs对ASS中好氧微生物3h接触毒性试验表明当Ce02NPs浓度小于100 mg.L-1时,其对微生物毒性效应较弱,当浓度大于100 mg-L-’时,随着作用浓度的增长,呼吸抑制率迅速增强,它对ASS中好氧微生物的半数效应浓度(ECso)为527.39 mg-L-1。2. CeO2 NPs(1和10 mg.L-1)急性作用(1周期和20 d)对污水生物处理效果的影响：CeO2 NPs对ASS暴露1周期后,下个周期内污染物去除规律变化研究结果表明,实验组S1 (1mg·L-1 CeO2NPs)和S2 (10mg·L-1 CeO2NPs)中有机物、氮与磷的去除规律与对照组S0 (0mg·L-1 CeO2NPs)基本一致。CeO2 NPs对ASS作用1个污泥龄(20 d)后,与S0相比,S1和S2出水水质与污泥沉降性能没有明显差别。3. CeO2NPs慢性作用(150d)对污水生物处理效果的影响：Ce02NPs对ASS作用150 d,研究表明,S1和S2出水COD、NO2--N与SO一致。S1和S2出水NH4+-N相对于S0的1.63 mg·L-1分别升至4.33mg·L-1和6.26 mg·L-1；出水N03--N相较于S0的5.39 mg·L-1分别降至4.55 mg·L-1和3.91 mg·L-1。S1和S2中TN去除率分别从78.6%和78.3%降至71.3%和67.5%,出水TP分别由0.23 mg·L-1和0.29 mg·L-1上升至0.47 mg·L-1和0.58 mg-L-1,去除率分别下降了4.8%和6%。SO污泥容积指数(SVI)为82 mL·g-1,S1和S2的SVI值升至94 mL·g-1和109 mL·g1,污泥沉降性能变差。4.ASS中微生物群落结构分析结果表明,CeO2NPs的慢性作用(150 d)未对ASS中微生物群落多样性造成明显影响,但对Proteobacteria菌群有抑制作用,对Actinobacteria菌群有促进作,同时抑制与促进的程度与CeO2 NPs浓度呈正相关。CeO2 NPs慢性作用使反硝化作用菌群丰度提升,降低了硝化功能菌群(Nitrosomonas和Nitrospire)和与污泥沉降相关的菌群Zoogloea丰度,且10 mg·L-1的抑制作用高于1 mg·L-1。CeO2 NPs慢性作用抑制了ASS中聚磷菌(PAOs)菌群丰度,相反,却使系统中聚糖菌(GAOs) Defluviicoccus丰度提升。
[Abstract]:In recent years, nanomaterials (NMs) has been widely used in all aspects of human production and life because of its excellent physical and chemical properties. Mass production and use of NMs will inevitably lead to its release in the water environment. At present, the potential risk of NMs to human body and other organisms has been widely concerned by scholars, but there is still a lack of research on the possible risk of sewage biological treatment process. In this paper, cerium oxide nanoparticles (CeO2 NPs), which is one of the most promising market prospects, were selected to study the changes of effluent quality and microbial community structure in ASS after its acute and chronic effects on (ASS) in activated sludge system. the conclusions were as follows: the exposure toxicity test of 1.CeO2 NPs to aerobic microorganisms in ASS for 3 h showed that when the concentration of Ce02NPs was less than 100 mg.L-, the toxicity to microorganisms was weak. When the concentration was more than 100 mg-L-', the respiratory inhibition rate increased rapidly with the increase of action concentration, and the half effect concentration of (ECso) on aerobic microorganisms in ASS was 527.39 mg-L-1.2.. Effects of acute effects of CeO2NPs (1 and 10 mg.L-1) on biological treatment of sewage: after one cycle of CeO2NPs exposure to ASS, the results of pollutant removal in the next cycle showed that the organic compounds in S1 (1mg 路L-1 CeO2NPs) and S2 (10mg 路L-1 CeO2NPs) in the experimental group were organic matter in the experimental group S1 (1mg 路L-1 CeO2NPs) and S2 (10mg 路L-1 CeO2NPs). The removal regularity of nitrogen and phosphorus was basically the same as that of control group S0 (0mg 路L-1 CeO2NPs). After CEO 2 NPs treated ASS with one sludge age (20 days), there was no significant difference between S1 and S2 effluent quality and sludge sedimentation performance. 3. The effect of CeO2NPs chronic action (150d) on the biological treatment of sewage: the effect of Ce02NPs on ASS for 150d. The results showed that the COD,NO2--N of S1 and S2 effluent was consistent with that of SO. The NH4-N of S1 and S2 effluent increased to 4.33mg 路L-1 and 6.26 mg 路L-1, respectively, compared with S0, and the NH4-N of S1 and S2 effluent increased to 4.33mg 路L-1 and 6.26 mg 路L-1, respectively. The removal rates of TN in effluent N03 鈮，

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