Viitala Mirka, Tsering Tenzin, Hyvönen Maria, Reinikainen Satu-Pia, Mänttäri Mika
Department of Separation Science, LUT School of Engineering Sciences, Lappeenranta-Lahti University of Technology LUT, Sammonkatu 12, Mikkeli, 50130, Finland.
Department of Separation Science, LUT School of Engineering Sciences, Lappeenranta-Lahti University of Technology LUT, Sammonkatu 12, Mikkeli, 50130, Finland.
J Environ Manage. 2025 Aug;389:126093. doi: 10.1016/j.jenvman.2025.126093. Epub 2025 Jun 5.
Microplastic (MP) pollution has been widely related to the discharges from wastewater treatment plants (WWTPs), but studies evaluating MP abundancies and qualities in both discharges and recipient water bodies have rarely been reported. To assess this, microplastics (≥100 μm) were analyzed from influent, effluent, and sludge of three Finnish WWTPs as well as from the sediments of their recipient waterbodies. The studied WWTPs utilized different treatment methods varying from secondary treatment to tertiary treatments with membrane bioreactor (MBR) and sand filtration. Results demonstrated high removal of MPs in all studied processes (>99 %), but the highest removal of MPs was reached at the MBR-based WWTP. Based on our calculations, over one third of the MPs entering the studied WWTPs were likely removed from the wastewater treatment process to other fractions than final sludge or effluent, such as materials removed with screening or grit separation. The role of the fractions in the environmental MP pollution would need further studies. It was estimated that at least 258 million MPs (≥100 μm) were discharged to the Lake Saimaa via studied WWTPs daily. MP concentrations in sediment samples were relatively low, and the types of detected MPs did not show direct linkages with the discharged MPs from the WWTPs. Blank correction was applied to all provided data together with the original data. As a result, the need for more precise blank correction was highlighted.
微塑料（MP）污染与污水处理厂（WWTPs）的排放物密切相关，但评估排放物和受纳水体中微塑料丰度和质量的研究鲜有报道。为评估此情况，对芬兰三座污水处理厂的进水、出水和污泥以及其受纳水体的沉积物中的微塑料（≥100μm）进行了分析。所研究的污水处理厂采用了从二级处理到三级处理（包括膜生物反应器（MBR）和砂滤）等不同的处理方法。结果表明，在所有研究过程中微塑料的去除率都很高（>99%），但基于膜生物反应器的污水处理厂微塑料去除率最高。根据我们的计算，进入所研究污水处理厂的微塑料中，超过三分之一可能在废水处理过程中被去除到最终污泥或出水以外的其他部分，例如通过筛分或沉砂分离去除的物质。这些部分在环境微塑料污染中的作用需要进一步研究。据估计，通过所研究的污水处理厂，每天至少有2.58亿个微塑料（≥100μm）排放到塞马湖。沉积物样本中的微塑料浓度相对较低，检测到的微塑料类型与污水处理厂排放的微塑料没有直接联系。对所有提供的数据以及原始数据都进行了空白校正。结果凸显了更精确空白校正的必要性。
