Stochastic Analysis of Virus Transport in Aquifers

9725086 Welty拟议工作的目的是建立一个病毒在含水层中运输的三维随机模型，并通过将其与现有的实地观测结果进行比较来评估该模型的实用性。待验证的假设是，与其他现有模型相比，随机谱方法提供了一种改进的野外尺度病毒运输表示。提出这项工作的动机来自：(1)公共卫生需要预测浅层饮用水含水层中的病毒运输，因为有证据表明，许多水传播疾病的爆发可归因于供水井受到来自土地处置废物的非本地病毒病原体的污染；(2)缺乏适当的现有模型来代表异质环境中大规模（数十至数百米）的病毒运输。由于在大尺度上确定非均质含水层结构是困难和不切实际的，因此需要在确定性计算之上采用随机方法。该模型将通过使用谱摄动分析来评估局部尺度病毒运输现象与含水层渗透率三维相关随机场模型耦合的影响。结果将是一组平均微分方程，表示在场尺度上自由病毒的传输和附着病毒的质量守恒。预计平均方程将包括场尺度的平流、分散、分离、过滤和吸附系数的数学表达式，这些系数取决于含水层的统计性质和局部尺度的病毒运输参数。该理论将预测局部尺度过程和场尺度异质性之间的相互作用，以及这种相互作用对大规模病毒运输的重要性。所得模型可以简化，也适用于地下水中非生物胶体的运动。

9725086 Welty The objective of the proposed work is to develop a three-dimensional stochastic model of virus transport in aquifers and to evaluate the usefulness of the model by comparing it to available field observations. The hypothesis to be tested is that the stochastic spectral approach provides an improved representation of field-scale virus transport compared to other currently available models. The motivation for the proposed work arises from: (1) the public health need to predict virus transport in shallow drinking water aquifers due to evidence that many waterborne disease outbreaks can be attributed to contamination of water supply wells by nonindigenous viral pathogens emanating from land-disposed wasters, and (2) the lack of appropriate existing models to represent virus transport at large scales (tens to hundreds of meters) in heterogeneous settings. A stochastic approach is needed over a deterministic computation because defining a heterogeneous aquifer structure deterministically for large scales is difficult and impractical. The model will be derived by using spectral perturbation analysis to evaluate the effect of coupling of local-scale virus transport phenomena with a three-dimensional, correlated-random-field model of aquifer permeability. The result will be a set of mean differential equations representing the transport of free viruses and conservation of mass of attached viruses at the field scale. It is expected that the mean equations will include mathematical expressions for field-scale advection, dispersion, detachment, filtration and adsorption coefficients that are dependent on aquifer statistical properties and local-scale virus transport parameters. The theory will predict the interaction between local-scale processes and field-scale heterogeneities and the importance of this interaction on large-scale virus transport. The resulting model could be simplified and applied also to the movement of abiotic colloids in groundwater.