Iskandarani Shaima, Manjunath Sarvajith, Busquets Rosa, Raeli Lorenzo, Saikaly Pascal E, Campos Luiza C
Centre for Urban Sustainability and Resilience, Department of Civil, Environmental and Geomatic Engineering, University College London, Gower St, Bloomsbury, London, WC1E 6BT, UK.
Biological and Environmental Science and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
Sci Rep. 2025 Aug 17;15(1):30089. doi: 10.1038/s41598-025-15504-9.
The presence of nanoplastics (NPs) in sewage treatment plants (STPs) remains a critical yet underexplored environmental issue. Here, we present a novel investigation into the occurrence, recovery, and characterization of nanoplastics and small-size microplastics (50-2500 nm) in raw and treated sewage effluent from a full-scale STP (treating 4000 m/day) operating with activated sludge. To our knowledge, this research includes the first confirmed assessment of nanoplastics in such a system and applies nano-flow cytometry to wastewater analysis for the first time globally. It is also the first study addressing micro- and nanoplastics in wastewater in Saudi Arabia, advancing plastic particle analysis in complex matrices. Particles in the 50- < 100 nm range accounted for 44% of total particles detected in STP effluents. Overall, plastic particles accounted for 16% (± 10%) of total particles within 50-2500 nm in raw sewage, increasing to 41% (± 13%) in treated effluent. This increase highlights the inefficiency of conventional treatment in fully removing plastic particles and suggests preferential removal based on size or density. The composition of a representative selection of particles was characterized by micro-Raman spectroscopy and Scanning Electron Microscopy with Energy-Dispersive X-ray. Identified polymers included polystyrene, polyvinyl chloride, polyethylene, polytetrafluoroethylene, polyamide, and polypropylene. These findings provide important insights into treated sewage composition, particularly for reuse in arid regions.
污水处理厂中纳米塑料（NPs）的存在仍然是一个关键但尚未充分探索的环境问题。在此，我们对一座采用活性污泥法运行的全规模污水处理厂（日处理量4000立方米）的原污水和处理后的污水排放物中纳米塑料和小尺寸微塑料（50 - 2500纳米）的出现情况、回收情况及特性进行了一项新的调查。据我们所知，这项研究包括了对该系统中纳米塑料的首次经确认的评估，并首次在全球范围内将纳米流式细胞术应用于废水分析。这也是沙特阿拉伯首次针对废水中的微塑料和纳米塑料开展的研究，推动了复杂基质中塑料颗粒的分析。在50 - <100纳米范围内的颗粒占污水处理厂排放物中检测到的总颗粒的44%。总体而言，塑料颗粒在原污水中占50 - 2500纳米范围内总颗粒的16%（±10%），在处理后的排放物中增至41%（±13%）。这种增加凸显了传统处理方法在完全去除塑料颗粒方面的低效性，并表明可能基于尺寸或密度进行优先去除。通过显微拉曼光谱和带有能量色散X射线的扫描电子显微镜对代表性颗粒样本的组成进行了表征。鉴定出的聚合物包括聚苯乙烯、聚氯乙烯、聚乙烯、聚四氟乙烯、聚酰胺和聚丙烯。这些发现为处理后的污水成分提供了重要见解，特别是对于干旱地区的污水回用而言。
