Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, FI-33014, Finland.
Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 589, FI-33014, Finland.
Environ Pollut. 2024 Dec 15;363(Pt 2):125251. doi: 10.1016/j.envpol.2024.125251. Epub 2024 Nov 5.
Pulp and paper wastewater sludges are waste streams produced in major quantities across the world. The recycling of these organic sludges, for example to soil amendments, is desired in the circular economy but carries the risk of potential pollutants to be also introduced into the environment. Pulp and paper wastewater sludges have been scarcely studied matrices in the microplastic research due to their complex composition. In this study, we optimized an extraction process for microplastics from pulp and paper wastewater sludges, and quantified and characterized microplastics down to 20 μm in primary sludge and biosludge generated at the wastewater treatment plant of a multi-product pulp and paper mill in Finland. The occurrence of microplastics was high in primary sludge, 900-1600 microplastics g dry weight, while the maximum number of detected microplastics in biosludge samples remained at 210 g dry weight. Biosludge samples suffered from larger amounts of remaining solids after the extraction process, thus compromising the detection of smaller microplastics (<100 μm) and increasing the uncertainty related to the interpretation of the results. The most prevalent microplastic shape in all samples was fragment, and the most recurring polymer types were polyethylene and polypropylene, while a polystyrene-based copolymer represented approximately 10% of identified microplastics in primary sludge. The present study advances the development of microplastic analysis of the challenging pulp and paper wastewater sludges and brings novel information to the progressing discussion of their circulation potential.
纸浆和造纸废水污泥是世界范围内大量产生的废物流。在循环经济中，这些有机污泥的回收（例如用作土壤改良剂）是人们所期望的，但也存在将潜在污染物引入环境的风险。由于其复杂的组成，纸浆和造纸废水污泥在微塑料研究中一直是研究较少的基质。在这项研究中，我们优化了从纸浆和造纸废水污泥中提取微塑料的方法，并对芬兰一家多产品纸浆和造纸厂的废水处理厂产生的初沉污泥和生物污泥中的微塑料进行了定量和特性分析，粒径小至 20 μm。初沉污泥中的微塑料含量很高，为 900-1600 个微塑料 g 干重，而生物污泥样品中检测到的最大微塑料数量仍保持在 210 g 干重。生物污泥样品在提取过程后会残留更多的固体，从而影响了对较小微塑料（<100 μm）的检测，并增加了对结果解释的不确定性。所有样品中最常见的微塑料形状是碎片，最常见的聚合物类型是聚乙烯和聚丙烯，而聚苯乙烯基共聚物约占初沉污泥中鉴定出的微塑料的 10%。本研究推进了对具有挑战性的纸浆和造纸废水污泥中微塑料分析的发展，并为正在进行的关于其循环潜力的讨论提供了新的信息。
