Modelling Pollution transport in Constructed Wetlands

项目要点：-开发稳健的模型，能够模拟人工湿地中的溶质和微塑料迁移过程、养分去除效率和水力效率。-开发一种基于机器学习的贝叶斯方法不确定性量化方法，以调查关键的建模参数，并反向量化和减少在本研究范围内开发的数值建模工具的不确定性。我们将使用现有的现场数据进行验证和校准过程。-进行情景模拟，以调查气候变化、植被组成的季节和年际变化，以及池塘的几何设计对人工湿地性能及其污染去除效率的影响。概述：人工湿地(CWS)是一种生态工程系统，它使用土壤、植被和生物来处理水，去除溶质和固体污染。它是水-植被-土壤之间的相互作用，控制着湿地的物理、化学和生物处理过程。这些“自然资本”资产是处理市政和工业废水、灰水和雨水径流的最有效措施之一。水的运动动力学对污染物的去除起着关键作用，因为它影响处理污染物的水力停留时间。植物群落对湿地的水动力和性能有显著的影响，因为它们产生水流阻力，改变速度场，影响混合特性，使悬浮物落到湿地床上。植被生长和枯萎的季节变化影响系统的性能。此外，随着时间的推移，微生物群落将对污水中的有机和金属污染物做出反应。近年来，一些研究对人工湿地中污染物的迁移机制进行了研究。然而，在对影响湿地中溶质和固体迁移的物理、生物过程进行建模方面，关键的知识差距仍然存在。主要目的是开发一种强大的数值模拟工具，能够准确地模拟人工湿地中的污染物迁移和储存过程，以量化人工湿地的养分去除效率和水力效率。开发这样的模型对于优化和有效地设计、运营和维护这些自然资本资产至关重要。模型验证和微调将使用我们与诺福克河信托基金合作的现有项目中的现场示踪剂研究数据进行。该项目还将调查和量化气候变化以及植被组成的季节和年际变化对CWS内的表现、混合和扩散过程的影响，为CWS的设计和运营提供信息。因此，该项目将通过模拟和优化人工湿地自然资本资产的表现，在环境保护和综合流域管理方面带来阶段性的变化，并在水务行业对这些系统进行大量投资的情况下产生重要影响。

Project Highlights: - Development of robust model capable of simulating solute and microplastic transport processes, nutrient removal efficiency, and hydraulic efficiency in constructed wetlands. - Development of a machine learning-based Bayesian approach uncertainty quantification methodology to investigate the key modelling parameters, and inversely quantify and reduce the uncertainties of the numerical modelling tool developed within this study. We will use existing field-based data for validation and calibration processes.- Undertaking scenario modelling to Investigate the effects of climate variability, seasonal and interannual variation in vegetation composition, as well as the geometrical design of the pond on the performance of the constructed wetlands and their pollution removal efficiency.Overview: Constructed wetlands (CWs) are ecologically engineered systems that use soil, vegetation, and organisms to treat water and remove solute and solid pollution. It is the interplay between water-vegetation-soil that governs the wetland physical, chemical, and biological treatment processes. These 'Natural Capital' assets are one of the most effective measures to treat municipal and industrial wastewater, greywater, and storm-water runoff. Dynamics of water movement plays a key role in the removal of pollutants, as it influences the hydraulic residence time for treating the pollutants. Plant communities have a prominent effect on the wetland hydrodynamics and performance, as they generate flow resistance, changes the velocity field, and affect mixing characteristics, enabling suspended material to fall to the wetland bed. Seasonal variation in vegetation growth and die-back influences the performance of the system. In addition, the microbial community will respond over time to the organic and metal pollutants that are constituents of the effluents. In recent years, several studies investigated the pollution transport mechanisms in constructed wetlands. However, critical knowledge gaps remain in modelling the physical, biological processes affecting solute and solid transport in wetlands. The main aim is to develop a robust numerical simulation tool capable of accurately modelling pollution transport and storage processes in the constructed wetlands to quantify the nutrient removal efficiency, and the hydraulic efficiency of constructed wetlands. Development of such model is critical for optimal and efficient design, operation, and maintenance of these natural capital assets. The model validation and fine-tunning with be undertaken using field-based tracer study data from our existing project in collaboration with the Norfolk Rivers Trust. This project will also investigate and quantify the effects of climate variability and seasonal and interannual variation in vegetation composition on the performance, mixing and dispersion processes within the CWs to inform the design and operation of CWs. Hence, this project will provide a step change in environmental protection and integrated catchment management by modelling and optimising the performance of constructed wetland natural capital assets, and significantly, be influential at a time of considerable investment in these systems by the water industry.