Environmental Engineering Laboratory, Department of Chemical Engineering, University Rovira and Virgili, Paisos Catalans Avenue 26, 43007, Tarragona, Catalonia, Spain.
Environmental Engineering Laboratory, Department of Chemical Engineering, University Rovira and Virgili, Paisos Catalans Avenue 26, 43007, Tarragona, Catalonia, Spain; Faculty of Pharmacy and Food Sciences, Universitat de Barcelona, Joan XXIII Avenue s/n, 08028, Barcelona, Catalonia, Spain.
Environ Pollut. 2023 Sep 15;333:122072. doi: 10.1016/j.envpol.2023.122072. Epub 2023 Jun 16.
Microplastic (MP) pollution is ubiquitous in the environment presenting a global problem for both scientists and the general public. One of the major pathways of MPs entering the natural environment is through wastewater treatment plants (WWTPs). Once MPs reach the natural environment, they are posing threat to aquatic ecosystems and public health. The aim of this study is to investigate the concentration, morphology, and composition of MPs in different treatment units of a WWTP. Sampling included different points across WWTP in the water and sludge lines. Pre-treatment of the samples consists of advanced Fenton oxidation, and alkaline and enzymatic digestion followed by density separation. Once the particles were isolated, their morphology and size were studied using a stereoscopic and optical microscope followed by final confirmation with ATR-FTIR and micro-FTIR spectroscopy. Microplastic particle concentrations exhibit significant reductions as water undergoes treatment in the WWTP. For summer sampling, concentrations decreased from 351 MP/L (influent) to 35 MP/L (primary clarifier), 32 MP/L (biological reactor), and 13 MP/L (2.3 MP/L) (secondary clarifier). Similarly, winter sampling showed reductions from 403 MP/L (influent) to 159 MP/L (primary clarifier), 178 MP/L (biological reactor), and 26 MP/L (5.6 MP/L) (secondary clarifier). Removal efficiency of WWTP is high and exceeds 96%. The most abundant morphology is fibers followed by fragments and films. Polymers such as PE, synthetic cellulose, PP, PVC, PE-PP, PEEA, PA, acrylamide, and PES are widely detected in different units of WWTP. The number of MPs that are avoided from being emitted into the environment through direct water discharge was estimated to be 9.1 × 10 MP/year. Removed MPs tend to accumulate in the sludge that is used for agricultural purposes although it should be managed as waste properly, avoiding the transition of MPs pollutants to terrestrial ecosystems adding to the number of MPs that will inevitably end up in receiving water bodies through direct WWTP effluent discharge that was set in 5.1 × 10 MP/year in the studied WWTP.
微塑料 (MP) 污染在环境中无处不在，是科学家和公众面临的全球性问题。MP 进入自然环境的主要途径之一是通过废水处理厂 (WWTP)。一旦 MPs 进入自然环境，它们就会对水生生态系统和公众健康构成威胁。本研究的目的是调查 WWTP 不同处理单元中 MPs 的浓度、形态和组成。采样包括 WWTP 中污水和污泥线的不同点。样品的预处理包括先进的芬顿氧化、碱性和酶消化，然后进行密度分离。一旦分离出颗粒，就使用立体显微镜和光学显微镜研究其形态和大小，然后使用 ATR-FTIR 和微 FTIR 光谱进行最终确认。微塑料颗粒浓度随着水在 WWTP 中的处理而显著降低。对于夏季采样，浓度从 351 MP/L（进水）降至 35 MP/L（初沉池）、32 MP/L（生物反应器）和 13 MP/L（2.3 MP/L）（二沉池）。同样，冬季采样显示浓度从 403 MP/L（进水）降至 159 MP/L（初沉池）、178 MP/L（生物反应器）和 26 MP/L（5.6 MP/L）（二沉池）。WWTP 的去除效率很高，超过 96%。最常见的形态是纤维，其次是碎片和薄膜。PE、合成纤维素、PP、PVC、PE-PP、PEEA、PA、丙烯酰胺和 PES 等聚合物在 WWTP 的不同单元中广泛检测到。通过直接排放水而避免排放到环境中的 MPs 数量估计为 9.1×10 MP/年。去除的 MPs 倾向于在用于农业目的的污泥中积累，尽管应该将其作为废物进行适当管理，避免 MPs 污染物转移到陆地生态系统，从而增加通过设定在研究的 WWTP 中每年 5.1×10 MP 的直接 WWTP 污水排放最终进入受纳水体的 MPs 数量。
