Urban Water Engineering, Luleå University of Technology, Luleå, Sweden.
Kristineberg Marine Research Station, IVL Swedish Environmental Research Institute, Fiskebäckskil, Sweden.
Water Res. 2021 Sep 1;202:117457. doi: 10.1016/j.watres.2021.117457. Epub 2021 Jul 23.
Microplastic particles in stormwater pose significant threats to the environment. This study investigated how effective a stormwater treatment train was at removing rubber, bitumen and other microplastics (incl. fibers, fragments, and paint particles) in the 100-300 µm and >300 µm size fractions from highway runoff. The two treatment trains comprise a gross pollutant trap (GPT) followed by either a vegetated bioretention cell or non-vegetated sand filter. Flow-proportional composite samples were taken from the highway runoff, GPT outflow and the outflow from the two parallel filters during nine rain events to determine overall treatment performance, as well as the performance of individual system components. The identified rubber, bitumen and other microplastic particles mainly represented the 100-300 µm fraction and included high ratios of rubber (30%) and bitumen (60%). Overall, the treatment train efficiently removed rubber, bitumen and other microplastic particles in the 100-300 µm size fraction from the stormwater. The filter cells accounted for a major share of this removal, as the GPT did not reduce microplastic particle concentrations. This observation is likely explained by the fact that the rubber, bitumen and other microplastic particles have a density close to the density of water and thus removal by sedimentation is decreased. This identified an inherent weakness of the system; more specifically, the high microplastic concentrations in the surface water of the GPT means there can be a risk of microplastic release through overflow pits when inflows surpass the system capacity. Despite some differences, both the vegetated bioretention cell and the non-vegetated sand filter removed rubber, bitumen and other microplastic particles to similar extent.
雨水径流中的微塑料颗粒对环境构成重大威胁。本研究调查了雨水处理系统在去除公路径流中 100-300μm 和>300μm 粒径范围内的橡胶、沥青和其他微塑料（包括纤维、碎片和油漆颗粒）方面的效果。这两个处理系统包括一个粗颗粒截污阱（GPT），后面分别是植被生物滞留池或无植被砂滤池。在九场降雨事件中，从公路径流、GPT 流出物和两个平行过滤器的流出物中采集了比例式复合样品，以确定整体处理性能以及各个系统组件的性能。确定的橡胶、沥青和其他微塑料颗粒主要代表 100-300μm 粒径范围，其中橡胶（30%）和沥青（60%）的比例较高。总的来说，处理系统有效地去除了雨水径流中 100-300μm 粒径范围内的橡胶、沥青和其他微塑料颗粒。过滤器单元在去除这些微塑料颗粒方面发挥了主要作用，因为 GPT 并未降低微塑料颗粒浓度。这种观察结果可能是由于橡胶、沥青和其他微塑料颗粒的密度接近水的密度，因此沉降去除的效果降低。这揭示了系统的一个固有弱点；具体来说，GPT 表面水中的高浓度微塑料意味着当流入量超过系统容量时，通过溢流坑释放微塑料的风险会增加。尽管存在一些差异，但植被生物滞留池和无植被砂滤池在去除橡胶、沥青和其他微塑料颗粒方面的效果相似。
