Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576.
NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 119077.
Environ Sci Technol. 2021 Apr 20;55(8):4205-4226. doi: 10.1021/acs.est.0c05681. Epub 2021 Mar 11.
Halogenated flame retardants (HFRs) have been extensively used in various consumer products and many are classified as persistent organic pollutants due to their resistance to degradation, bioaccumulation potential and toxicity. HFRs have been widely detected in the municipal wastewater and wastewater treatment solids in wastewater treatment plants (WWTPs), the discharge and agricultural application of which represent a primary source of environmental HFRs contamination. This review seeks to provide a current overview on the occurrence, fate, and impacts of HFRs in WWTPs around the globe. We first summarize studies recording the occurrence of representative HFRs in wastewater and wastewater treatment solids, revealing temporal and geographical trends in HFRs distribution. Then, the efficiency and mechanism of HFRs removal by biosorption, which is known to be the primary process for HFRs removal from wastewater, during biological wastewater treatment processes, are discussed. Transformation of HFRs via abiotic and biotic processes in laboratory tests and full-scale WWTPs is reviewed with particular emphasis on the transformation pathways and functional microorganisms responsible for HFRs biotransformation. Finally, the potential impacts of HFRs on reactor performance (i.e., nitrogen removal and methanogenesis) and microbiome in bioreactors are discussed. This review aims to advance our understanding of the fate and impacts of HFRs in WWTPs and shed light on important questions warranting further investigation.
卤代阻燃剂（HFRs）已广泛应用于各种消费品中，由于其难以降解、具有生物蓄积潜力和毒性，许多 HFRs 被归类为持久性有机污染物。HFRs 已在城市废水中和污水处理厂（WWTP）的污水处理固体中被广泛检测到，其排放和农业应用是环境 HFRs 污染的主要来源。本综述旨在提供全球范围内 WWTP 中 HFRs 的发生、命运和影响的最新概述。我们首先总结了记录废水中代表性 HFRs 存在情况的研究，揭示了 HFRs 分布的时间和地理趋势。然后，讨论了生物吸附去除 HFRs 的效率和机制，生物吸附是生物处理过程中去除 HFRs 的主要过程。还综述了实验室试验和全规模 WWTP 中通过非生物和生物过程转化 HFRs 的情况，特别强调了负责 HFRs 生物转化的转化途径和功能微生物。最后，讨论了 HFRs 对反应器性能（即氮去除和产甲烷）和生物反应器中微生物组的潜在影响。本综述旨在增进我们对 WWTP 中 HFRs 命运和影响的理解，并阐明需要进一步研究的重要问题。
