Oveisy Niousha, Rafiee Mohammad, Rahmatpour Ali, Nejad Ali Shahidi, Hashemi Marjan, Eslami Akbar
Department of Environmental Health Engineering, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Polymer Research Laboratory, Faculty of Chemistry and Petroleum Science, Shahid Beheshti University, Tehran, Iran.
Water Environ Res. 2022 Aug;94(8):e10765. doi: 10.1002/wer.10765.
Microplastic pollution is a serious threat to the biota and humans, and wastewater treatment plants act as a pathway for entering microplastics into the environment. This study discusses the identification and quantification of microplastics in the south of Tehran municipal WWTP. The sampling was repeated three times in a month, overall, nine times for water samples and once a month in total, three times for digested sludge samples by steel bucket with the WPO method. The microplastics from water and digested sludge samples were identified using the micro-Raman microscope. According to this study, 98.9% of microplastic particles in effluent and 99.2% of microplastics particles in the sludge were fibers. The influent contained an average of 180 ± 4.3 MP/L and was reduced to 5.3 ± 0.31 MP/L in the final effluent. Despite this significant reduction, we calculate that this WWTP releases 2.3 × 10 microplastics per day through final effluent and 1.61 × 10 particles per day through dried sludge into the environment. We performed micro-Raman analyses and ICP mass to measure the amount of heavy metal absorption of MPs. In addition, SEM analyses were used to study the surface morphology of microplastic particles. PRACTITIONER POINTS: Fourteen different polymers were identified in the influent, effluent, and digested sludge. The main collected shapes obtained were fiber, film, and fragment, which fiber was the predominant polymer in this WWTP. The plant releases 2.3 * 10 MPs per day to its downstream environment. This WWTP has average removal with an efficiency of 99.06%.
微塑料污染对生物群和人类构成严重威胁，污水处理厂是微塑料进入环境的一个途径。本研究讨论了德黑兰市南部污水处理厂微塑料的识别与量化。一个月内对水样进行了三次重复采样，总共采集了九次水样，对消化污泥样本每月采样一次，总共三次，采用WPO方法用钢桶采集。使用显微拉曼显微镜对水样和消化污泥样本中的微塑料进行识别。根据本研究，出水微塑料颗粒中98.9%以及污泥中微塑料颗粒中99.2%为纤维。进水平均含有180±4.3个微塑料/升，最终出水降至5.3±0.31个微塑料/升。尽管有显著减少，但我们计算得出，该污水处理厂每天通过最终出水向环境中排放2.3×10个微塑料，通过干污泥每天排放1.61×10个颗粒。我们进行了显微拉曼分析和电感耦合等离子体质谱分析，以测量微塑料的重金属吸收量。此外，还利用扫描电子显微镜分析研究了微塑料颗粒的表面形态。从业者要点：在进水、出水和消化污泥中识别出了14种不同的聚合物。主要收集到的形状为纤维、薄膜和碎片，其中纤维是该污水处理厂中占主导地位的聚合物。该工厂每天向下游环境排放2.3×10个微塑料。该污水处理厂的平均去除率为99.06%。
