Di Bella Gaetano, Corsino Santo Fabio, De Marines Federica, Lopresti Francesco, La Carrubba Vincenzo, Torregrossa Michele, Viviani Gaspare
Faculty of Engineering and Architecture, University of Enna "Kore", 94100 Enna, Italy.
Department of Engineering, University of Palermo, 90128 Palermo, Italy.
Membranes (Basel). 2022 Mar 29;12(4):371. doi: 10.3390/membranes12040371.
In this study, the presence of microplastics in the sludge of three wastewater treatment plants (WWTPs) was examined. The investigated WWTPs operated based on a conventional activated sludge (CAS) process, with (W1) or without (W2) primary clarification, and a membrane bioreactor process (MBR) (W3). The microplastics (MPs) concentration in the samples of W3 was approximately 81.1 ± 4.2 × 10 particles/kg dry sludge, whereas MPs concentrations in W1 and W2 were 46.0 ± 14.8 × 10 particles/kg dry sludge and 36.0 ± 5.2 × 10 particles/kg dry sludge, respectively. Moreover, MPs mainly consisted of fragments (66-68%) in the CAS plants, whereas the fractions of MPs shapes in the MBR sludge were more evenly distributed, although fiber (47%) was the most abundant fraction. Furthermore, samples from the MBR showed a greater diversity in MPs composition. Indeed, all the main polyesters (i.e., textile fibers and polyethylene terephthalate), polyolefins (i.e., polyethylene and polypropylene) and rubber (i.e., polybutadiene) were observed, whereas only polybutadiene, cellulose acetate and polyester were detected in the CAS plants. These findings confirmed that MPs from wastewater are transferred and concentrated in the waste sludge. This is a critical finding since sludge disposal could become a new pathway for microplastic release into the environment and because MPs might affect the fouling behavior of the membrane.
在本研究中，对三个污水处理厂（WWTPs）污泥中的微塑料存在情况进行了检测。所调查的污水处理厂采用传统活性污泥法（CAS）运行，其中一个有初沉池（W1），另一个没有初沉池（W2），还有一个采用膜生物反应器工艺（MBR）（W3）。W3样品中的微塑料（MPs）浓度约为81.1±4.2×10颗粒/千克干污泥，而W1和W2中的微塑料浓度分别为46.0±14.8×10颗粒/千克干污泥和36.0±5.2×10颗粒/千克干污泥。此外，在采用传统活性污泥法的污水处理厂中，微塑料主要由碎片组成（66 - 68%），而在膜生物反应器污泥中，微塑料的形状分布更为均匀，尽管纤维（47%）是最主要的部分。此外，膜生物反应器的样品在微塑料组成上表现出更大的多样性。实际上，观察到了所有主要的聚酯（即纺织纤维和聚对苯二甲酸乙二酯）、聚烯烃（即聚乙烯和聚丙烯）以及橡胶（即聚丁二烯），而在采用传统活性污泥法的污水处理厂中仅检测到了聚丁二烯、醋酸纤维素和聚酯。这些发现证实了废水中的微塑料会转移并浓缩在剩余污泥中。这是一个关键发现，因为污泥处置可能成为微塑料释放到环境中的新途径，并且微塑料可能会影响膜的污染行为。
