Global Centre for Environmental Remediation, The University of Newcastle, Callaghan, NSW, 2308, Australia; Global Innovative Centre for Advanced Nanomaterials (GICAN), The University of Newcastle, Callaghan, NSW, 2308, Australia.
Global Centre for Environmental Remediation, The University of Newcastle, Callaghan, NSW, 2308, Australia.
Water Res. 2020 Apr 15;173:115549. doi: 10.1016/j.watres.2020.115549. Epub 2020 Jan 29.
Wastewater treatment plants are a significant pathway of microplastics (MPs) to aquatic environments. To develop suitable management options and reduce microplastic emissions in treated effluent and sludge, we must first develop a reliable method to understand their transport and fate throughout the treatment process. An improved methodology was applied to determine the size, shape, polymer type and partitioning behaviour of MPs using a combination of oxidation treatment, fluorescent staining and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) to detect small MPs ≤20 μm in wastewater. The mean number of MPs (<5 mm) detected using this methodology was 11.80 ± 1.10 MP/L in raw sewage, 5.23 ± 0.25 MP/L in degritted wastewater, 7.91 ± 0.44 MP/L in waste activated sludge and 2.76 ± 0.11 MP/L in the final treated effluent. An increase in MPs following primary screening suggests that WAS is a sink for several stealth microplastics, including glitter, which is returned to the effluent during the treatment process. The estimated MP removal efficiency for the studied WWTP is relatively poor compared with global data for secondary WWTPs, which is likely due to the release of partially treated effluent into the Pacific Ocean via a second discharge point. The information generated through this study can be useful to; firstly, inform on-site wastewater management practices, and secondly, reduce MP concentrations in final treated effluents discharged to the marine environment.
污水处理厂是微塑料（MPs）进入水生环境的重要途径。为了开发合适的管理方案，并减少处理废水中和污泥中的微塑料排放，我们必须首先开发一种可靠的方法来了解它们在整个处理过程中的迁移和归宿。本研究应用一种改良的方法，结合氧化处理、荧光染色和衰减全反射傅里叶变换红外光谱（ATR-FTIR），来确定 MPs 的大小、形状、聚合物类型和分配行为，以检测废水中≤20μm 的小 MPs。该方法检测到 raw sewage 中平均 MPs（<5mm）的数量为 11.80±1.10 MPs/L，degritter 废水为 5.23±0.25 MPs/L，waste activated sludge 为 7.91±0.44 MPs/L，最终处理后的废水为 2.76±0.11 MPs/L。初级筛选后 MPs 的增加表明，WAS 是几种隐形微塑料（包括闪光片）的汇，这些微塑料在处理过程中会被重新释放到废水中。与全球二级 WWTP 的数据相比，该研究中 WWTP 的 MPs 去除效率相对较差，这可能是由于部分处理后的废水通过第二个排放点排放到太平洋中。通过这项研究产生的信息可以有用地：首先，为现场废水管理实践提供信息；其次，减少排放到海洋环境中的最终处理废水中的 MPs 浓度。
