Mechanics of plastic pollutants in rivers

河流中塑料污染物的机理

• 批准号: EP/Y001303/1
• 负责人: Sergio Maldonado
• 金额: $ 16.02万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FY001303%2F1
• 关键词: Mechanics; plastic; pollutants; rivers

According to the United Nations Environment Program, plastic pollution of marine ecosystems is one of the key emerging issues affecting the environment. It is difficult to overstate the severity and breadth of the problem. Plastic pollutants are not only a threat to virtually all marine life, but their breaking down into microplastics also poses a major health hazard to humans (alarmingly, microplastics have been recently found in human placentas). The vast majority of plastic litter found in the oceans - the volume of which is predicted to increase in the coming decades - has its source inland, and one of the main pathways by which it enters the seas is via rivers. However, research carried out so far on the transport and fate of plastics in bodies of water has focused almost exclusively on the marine environment, and on micro-plastics in particular. A sensible - and as of now, largely unexplored - approach is that of addressing the issue of larger-size plastic litter in rivers, where plastics: (a) have not yet had the time to break down into microplastics, and (b) are localised rather than dispersed over very large areas (of oceanic scales). What is more, the UK generates more plastic waste per person than almost any other country (second only to the USA), some of which has been found polluting other countries' environments. Thus, contributing to the generation of knowledge and designing solutions to this worldwide environmental crisis is a moral imperative for UK-based researchers and taxpayers. Moreover, this generation of new knowledge may lead to an innovative domestic industry of river cleaning technologies. To ensure efficacy and optimal efficiency, any engineering intervention aimed at removing plastics from rivers must be based on a solid understanding of the mechanics of plastic transport in these environments. Nevertheless, relevant studies are scarce, especially when compared with similar research in marine settings (where hydrodynamics are markedly different from those of rivers). Physics-based models for the transport of plastics in rivers, which enable us to accurately predict where plastic is most likely to be found, are urgently needed. Therefore, this research project aims to generate fundamental insights on the mechanics of plastic transported by rivers, with a view to inform and enable effective river-cleaning measures and technologies aimed at addressing the pressing issue of plastic litter in the environment. Well-controlled experiments will be carried out in two different facilities in order to analyse the mechanics of plastic particles in (i) homogeneous turbulence and (ii) wall-bounded turbulent flows. The latter represent flow conditions similar to those found near the bed of a river, while the former mimic those away from the bed. For homogeneous turbulence, we will employ a specialised facility at ETH Zurich (the international collaborator), while wall turbulence experiments will be carried out in a 16 m long hydraulic flume at the University of Southampton (the host institution). State-of-the-art experimental techniques will be employed, such as Particle Image Velocimetry and Particle Tracking Velocimetry. The influence of particle density, size, shape and rigidity (given a total of 14 different types of plastic particles) will be investigated.

根据联合国环境规划署的数据，海洋生态系统的塑料污染是影响环境的关键新兴问题之一。这个问题的严重性和广度怎么说都不为过。塑料污染物不仅对几乎所有海洋生物构成威胁，而且它们分解成微塑料也对人类健康构成重大危害(令人担忧的是，最近在人类胎盘中发现了微塑料)。海洋中发现的绝大多数塑料垃圾--预计其数量在未来几十年将会增加--都来自内陆，进入海洋的主要途径之一是通过河流。然而，到目前为止，关于塑料在水体中的运输和去向的研究几乎完全集中在海洋环境，特别是微型塑料。解决河流中较大尺寸塑料垃圾的问题是一种明智的--而且到目前为止基本上还没有探索--的方法，在河流中，塑料：(A)还没有时间分解成微塑料，(B)被局部化，而不是分散在非常大的区域(海洋规模)。更重要的是，英国人均产生的塑料垃圾比几乎任何其他国家都多(仅次于美国)，其中一些已经被发现污染了其他国家的环境。因此，对英国的研究人员和纳税人来说，为创造知识并为这场全球环境危机设计解决方案是道德上的当务之急。此外，这一代新知识可能会导致国内河流清洁技术行业的创新。为了确保效果和最佳效率，任何旨在从河流中清除塑料的工程干预措施都必须建立在对这些环境中塑料运输机制的扎实了解的基础上。然而，相关研究很少，特别是与海洋环境中的类似研究相比(那里的水动力学与河流的水动力学明显不同)。迫切需要基于物理的塑料在河流中的运输模型，使我们能够准确地预测哪里最有可能找到塑料。因此，这一研究项目旨在对河流运输塑料的机理产生基本的见解，以期为解决环境中塑料垃圾的紧迫问题而采取有效的河流清理措施和技术并使之成为可能。为了分析塑料颗粒在(I)均匀湍流和(Ii)壁面边界湍流中的力学行为，将在两个不同的装置中进行良好控制的实验。后者表示类似于河床附近的水流状况，而前者则模拟远离河床的水流状况。对于均匀湍流，我们将在苏黎世理工学院(国际合作者)使用专门的设备，而壁面湍流实验将在南安普顿大学(主办机构)16米长的水力水槽中进行。将采用最先进的实验技术，如粒子图像测速和粒子跟踪测速。将研究颗粒密度、大小、形状和刚性(假设总共14种不同类型的塑料颗粒)的影响。