Australian Rivers Institute, Griffith School of Environment, Griffith University, Gold Coast, QLD 4222, Australia.
Australian Rivers Institute, Griffith School of Environment, Griffith University, Gold Coast, QLD 4222, Australia.
Water Res. 2017 Apr 1;112:93-99. doi: 10.1016/j.watres.2017.01.042. Epub 2017 Jan 25.
Wastewater effluent is expected to be a pathway for microplastics to enter the aquatic environment, with microbeads from cosmetic products and polymer fibres from clothes likely to enter wastewater treatment plants (WWTP). To date, few studies have quantified microplastics in wastewater. Moreover, the lack of a standardized and applicable method to identify microplastics in complex samples, such as wastewater, has limited the accurate assessment of microplastics and may lead to an incorrect estimation. This study aimed to develop a validated method to sample and process microplastics from wastewater effluent and to apply the developed method to quantify and characterise wastewater-based microplastics in effluent from three WWTPs that use primary, secondary and tertiary treatment processes. We applied a high-volume sampling device that fractionated microplastics in situ and an efficient sample processing procedure to improve the sampling of microplastics in wastewater and to minimize the false detection of non-plastic particles. The sampling device captured between 92% and 99% of polystyrene microplastics using 25 μm-500 μm mesh screens in laboratory tests. Microplastic type, size and suspected origin in all studied WWTPs, along with the removal efficiency during the secondary and tertiary treatment stages, was investigated. Suspected microplastics were characterised using Fourier Transform Infrared spectroscopy, with between 22 and 90% of the suspected microplastics found to be non-plastic particles. An average of 0.28, 0.48 and 1.54 microplastics per litre of final effluent was found in tertiary, secondary and primary treated effluent, respectively. This study suggests that although low concentrations of microplastics are detected in wastewater effluent, WWTPs still have the potential to act as a pathway to release microplastics given the large volumes of effluent discharged to the aquatic environment. This study focused on a single sampling campaign, with long-term monitoring recommended to further characterise microplastics in wastewater.
污水废水预计将成为微塑料进入水生态环境的途径之一，其中化妆品中的微珠和衣物中的聚合物纤维很可能进入到污水处理厂（WWTP）。迄今为止，很少有研究对污水中的微塑料进行定量分析。此外，由于缺乏标准化和适用的方法来识别污水等复杂样品中的微塑料，限制了对微塑料的准确评估，并且可能导致错误的估计。本研究旨在开发一种经过验证的方法，以从污水废水中采样和处理微塑料，并应用所开发的方法来量化和描述来自使用一级、二级和三级处理工艺的三个 WWTP 的污水废水中的基于污水的微塑料。我们应用了一种大容量采样装置，该装置可原位对微塑料进行分级，并采用高效的样品处理程序，以改善污水中微塑料的采样，并最大限度地减少对非塑料颗粒的错误检测。实验室测试表明，在使用 25μm-500μm 筛网的情况下，该采样装置可捕获 92%至 99%的聚苯乙烯微塑料。本研究调查了所有研究的 WWTP 中的微塑料类型、尺寸和疑似来源，以及在二级和三级处理阶段的去除效率。使用傅里叶变换红外光谱对疑似微塑料进行了特征描述，发现 22%至 90%的疑似微塑料为非塑料颗粒。最终出水、二级处理出水和一级处理出水中分别发现平均 0.28、0.48 和 1.54 个微塑料/升。本研究表明，尽管污水废水中检测到的微塑料浓度较低，但鉴于排放到水生态环境中的污水废水体积庞大，WWTP 仍然有可能成为释放微塑料的途径。本研究仅关注了单次采样活动，建议进行长期监测以进一步对污水中的微塑料进行特征描述。
