污水处理厂PFAS来源、迁移转化与去除方法

Source,transformation and removal of PFAS in wastewater treatment plants

人工合成全氟/多氟烷基化合物(PFAS)因其结构中含有碳-氟键,使其具有疏水、疏油等特性而被广泛应用于人类生产、生活之中.使用后的PFAS大多都汇集于污水处理厂中,成为环境中一个重要的汇.加之,污水生物处理过程大多只能对PFAS前体物质进行转化而不是降解,以至于常常导致出水中PFAS浓度高于进水,甚至成为PFAS的源.因进入人体的PFAS的生物累积性和持久性会造成不同程度人体健康损害,所以,欧美等国家已开始限制PFAS的使用并致力于去除现存环境中的PFAS.在系统总结PFAS来源、浓度、转化和去除的基础上,对现存各种去除方法进行了效果分析,以便为后续污水处理厂污水、污泥中PFAS迁移转化及去除等进一步研究提供参考.最终得出,现有去除方法对PFAS去除降解效果十分有限;对出水吸附PFAS后原位同步降解、采用污泥焚烧处理似乎是最为有效的去除PFAS手段,也是未来该领域应重点研发的技术.

Synthetic perfluoro/polyfluoroalkyl compounds(PFAS)are widely used in consumer products and human life due to their hydrophobic and oleophobic properties,which is owing to unique molecular structure and carbon-fluorine bonds.Most of PFAS after use are discharged into wastewater treatment plants(WWTPs),forming a major sink of PFAS in the environment.Moreover,biological wastewater treatment can only transform PFAS precursors instead of degrading them,often resulting in higher PFAS concentration in the effluent than in the influent so that WWTPs could even become a source of PFAS.Europe and also other countries have limited PFAS for use owing to their persistency and bio-accumulation in human body,and have also started to remove PFAS in the environment.Based on reviewing the source,concentration,transformation and removal of PFAS,all possible PFAS removed pathways are analysed on their removal efficiencies,and finally some key approaches to removing PFAS are identified to provide a reference on further research on the migration,transformation and removal of PFAS in effluent and excess sludge from WWTPs.Finally,some conclusions are drawn that current removal methods for PFAS are very limited and that the adsorption and in-situ solid-phase photo-degradation of PFAS in effluent as well as sludge incineration might be the most efficient technologies removing PFAS from WWTPs,which should be focused on future research&development.