富勒烯C60纳米颗粒在污泥厌氧消化过程中的归趋、效应及其环境释放特征

Fullerene C60’ special physicochemical properties give their wide application with rapid growing in production and use. Those raise significant concerns regarding the environmental risks and human health. The nanoparticles will be, either directly or indirectly, introduced into the sewage during the product manufacturing, use and disposal. Consequently, wastewater treatment plant can become an important route for their discharge into the environment. Studies available report most C60’s water suspension (nC60) can be removed by accumulating in the wastewater sludge during the wastewater treatment. As a result, those nC60 nanoparticles could enter into the subsequent treatment of sludge anaerobic digestion, and eventually be discharged into the environment as the land application of sludge. However, the fate and effect of nC60 during the anaerobic digestion treatment, and their release to environment during the land application have seldom been investigated. In this study, the batch sludge anaerobic digestion experiment will be conducted to investigate the distribution and their kinetics of nC60 during the anaerobic digestion, as well as the effect of nC60 on the digestion process. Also, the adsorption-desorption experiment will be performed to study the adsorption-desorption behavior of nC60 on the sludge, soil for different land applications and sludge treated soil, and the release during the land application of sludge. Our results are expected to provide important information for evaluating the fate and risk of nC60 during the wastewater treatment and land application of sludge.

富勒烯C60纳米颗粒因具有优异物理化学特性而被广泛应用，其产量和使用量日益增加，与此同时其对环境和人体健康的潜在风险引起了广泛关注。C60在生产、使用及处置中可直接间接进入污水，使污水处理厂成为其向环境中释放的重要途径。污水处理过程中，C60水悬浮液（nC60）主要吸附蓄积在污泥中而被去除，因而会进入污泥厌氧消化过程，最终可能随污泥土地利用而排入环境。然而，nC60在污泥消化过程中的归趋，对厌氧消化的影响，及在污泥土地利用中是否向环境中释放，目前还没有系统研究。为此，本研究采用批式污泥厌氧消化实验，研究nC60在污泥厌氧消化过程中的分布、及其动力学特征，以及对厌氧消化的影响；利用等温吸附解吸实验，探索nC60在污泥、不同土地利用类型土壤及污泥施用土壤中的吸附解吸特征，研究其在污泥土地利用中的释放性，以期对nC60在污水处理及污泥土地利用中的迁移转化规律和风险评价提供研究基础。

富勒烯C60纳米颗粒是一种环境新兴污染物。C60在生产、使用及处置中可直接间接进入污水，使污水处理厂成为其向环境中释放的重要途径。污水处理过程中，C60水悬浮液（nC60）主要吸附蓄积在污泥中而被去除，因而会进入污泥厌氧消化过程，最终可能随污泥土地利用而排入环境。然而，nC60在污泥消化过程中的归趋，对厌氧消化的影响，及在污泥土地利用中是否向环境中释放，目前还没有系统研究。本研究，（1）基于液液萃取—液固萃取（冷冻干燥）—液相色谱法，建立了可用于污水和污泥/土壤中nC60定量分析的方法，线性相关系数R2 > 0.99，回收率 > 90%；（2）建立了可用于纳米颗粒新兴污染物评价的批式和连续式污泥厌氧消化系统，解析了nC60对污泥厌氧消化产气量、厌氧消化代谢、污染物去除及微生物群落结构的影响效应，发现nC60对污泥消化产甲烷量没有显著影响，但显著抑制其产气速率； 30天后显著影响污泥中碳水化合物和挥发性脂肪酸代谢过程; 对污泥厌氧消化相关菌群和功能基因具有显著影响，Anaerolineaceae受到抑制，而Peptostreptococcacease受到促进，Xenobiotic biodegradation, Amino acid，Lipid， Energy Metabolism等代谢基因受到限制抑制，而Translation，Cell motility，Nucleotide，Drug resistance等受到显著促进；（3）通过等温吸附、动力学实验及模拟污泥土地利用过程污染物环境释放实验，发现nC60在污泥上的吸附与污泥粒径、疏水性、zeta 电位等显著相关；在污泥土地利用过程中短期内其水迁移性低，但nC60在土壤的吸附/释放与土壤类型/性质显著相关，尤其是有机碳含量。本项目研究成果，为nC60及其他含碳纳米颗粒新兴污染物，从污水处理厂向土壤环境中释放及由此需要开展的环境风险评估，提供重要的理论和数据支撑。