School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia.
School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW, 2522, Australia.
Chemosphere. 2023 Sep;334:139011. doi: 10.1016/j.chemosphere.2023.139011. Epub 2023 May 23.
Nano/microplastic (NP/MP) pollution is a growing concern for the water environment. Wastewater treatment plants (WWTPs) are considered the major recipients of MP before discharging into local waterbodies. MPs enter WWTPs mainly from synthetic fibers through washing activities and personal care products. To control and prevent NP/MP pollution, it is essential to have a comprehensive understanding of their characteristics, fragmentation mechanisms, and the effectiveness of the current treatment processes used in WWTPs for NP/MP removal. Therefore, the objectives of this study are to (i) understand the detailed mapping of NP/MP in the WWTP, (ii) understand the fragmentation mechanisms of MP into NP, and (iii) investigate the removal efficiency of NP/MP by existing processes in the WWTP. This study found that fiber is the dominant shape of MP, and polyethylene, polypropylene, polyethylene terephthalate, and polystyrene are the major polymer type of MP in wastewater samples. Crack propagation and mechanical breakdown of MP due to water shear forces induced by treatment facilities (e.g., pumping, mixing, and bubbling) could be the major causes for NP generation in the WWTP. Conventional wastewater treatment processes are ineffective for the complete removal of MPs. Although these processes are capable of removing ∼95% of MPs, they tend to accumulate in sludge. Thus, a significant number of MPs may still be released into the environment from WWTPs on a daily basis. Therefore, this study suggested that using DAF process in the primary treatment unit can be an effective strategy to control MP in the initial stage before it goes to the secondary and tertiary stage.
纳米/微塑料 (NP/MP) 污染是水环境面临的一个日益严重的问题。污水处理厂 (WWTP) 被认为是 MP 在排入当地水体之前的主要接收者。MP 主要通过洗涤活动和个人护理产品中的合成纤维进入 WWTP。为了控制和防止 NP/MP 污染，必须全面了解它们的特性、碎片化机制以及 WWTP 中用于去除 NP/MP 的现有处理工艺的有效性。因此，本研究的目的是：(i) 了解 WWTP 中 NP/MP 的详细分布，(ii) 了解 MP 碎片化成 NP 的机制，以及 (iii) 研究 WWTP 中现有工艺对 NP/MP 的去除效率。本研究发现，纤维是 MP 的主要形状，聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚苯乙烯是废水中 MP 的主要聚合物类型。由于处理设施（例如泵送、混合和鼓泡）引起的水剪切力，MP 的裂纹扩展和机械破裂可能是 WWTP 中 NP 产生的主要原因。传统的废水处理工艺对于 MPs 的完全去除是无效的。尽管这些工艺能够去除约 95%的 MPs，但它们往往会在污泥中积累。因此，大量的 MPs 可能仍会每天从 WWTP 释放到环境中。因此，本研究建议在初级处理单元中使用 DAF 工艺可以是一种在进入二级和三级处理之前控制 MP 的有效策略。
