Modeling Coupled Dynamic Processes in Landfills: Holistic Long-Tern Performance Management to Improve Sustainability

许多接受城市固体废物的工程垃圾填埋场被归类为“干坟墓垃圾填埋场”，因为垃圾在低湿度条件下降解非常缓慢。作为替代方案，生物反应器垃圾填埋场应运而生，以应对这些条件。在生物反应器垃圾填埋场中，渗滤液再循环系统会增加水分并加速降解。生物反应器填埋场的性能是水-生物-机械耦合过程的结果，然而，工业缺乏一个全面的、整体的数学模型来考虑和有效地分析垃圾填埋场中的这些耦合过程。该项目将开发一种新的耦合数学工具，以便于设计和运营稳定、有效和可持续的工程垃圾填埋场，从而将对周围环境和公众的长期风险降至最低。该工具将使从业者和监管机构能够预测高度复杂的垃圾填埋场稳定期，并通过准确地考虑差异沉降和稳定期，允许规划有益地重新利用垃圾填埋场空间，如娱乐设施。由于有控制、可预测、快速的城市固体废物分解，稳定期缩短：(A)不可降解的城市固体废物可被开采和处理，减少填埋场内的填埋量；(B)关闭后的监测可缩短，相关支出大大减少；(C)可消除对土工合成衬垫长期性能和相关环境风险的关切。这项研究涉及多个学科，包括地质环境工程、可持续工程、生物学和计算力学。多学科的研究将为代表不足的群体提供一个独特的参与研究的机会。所提出的建模工具将结合并同时求解两相流模型、大应变显式力学模型和一阶衰减生物降解模型。该模型将考虑废物性质的同时变化，以预测垃圾填埋场中的耦合过程。具体来说，项目范围将包括：(A)开发一个新的数学模型，能够解释不同种类的废物、两相流动和水-生物力学耦合过程，并有效地预测垃圾填埋场的时空行为；(B)通过实验室和现场研究对模型进行验证，以达到对模拟结果准确性的置信度；(C)预测由于耦合过程导致的垃圾填埋场的时空沉降、斜坡稳定性和剪切响应；(D)基于概率分析对控制垃圾填埋场性能的主要系统变量进行评估；以及(E)将该工具应用于对过去的垃圾填埋场故障进行法医调查。该项目将提供一种工具，用于设计稳定和有效的工程垃圾填埋场，并使用水-生物-机械耦合过程优化现有垃圾填埋场。

Many engineered landfills that accept municipal solid waste are classified as "dry tomb landfills" because waste degrades very slowly due to low moisture conditions. As an alternative, bioreactor landfills have emerged to counter those conditions. In bioreactor landfills, leachate recirculation systems increase moisture and accelerate degradation. The performance of bioreactor landfills results from coupled hydro-bio-mechanical processes; however, industry lacks a comprehensive, holistic mathematical model that considers and effectively analyzes these coupled processes in landfills. This project will develop a new coupled mathematical tool to enable the design and operation of stable, effective and sustainable engineered landfills, thereby minimizing long-term risks to the surrounding environment and public. The tool will enable practitioners and regulators to predict the highly complex landfill stabilization period, and allow for the planning of beneficial reuse of landfill space, such as recreational facilities, by accurately accounting for a differential settlement and stabilization period. With controlled, predictable, rapid municipal solid waste decomposition and a reduced stabilization period: (a) non-degradable municipal solid waste may be mined and processed, reducing the amount of landfill mass encapsulated within a landfill; (b) post-closure monitoring can be shortened and associated expenditures considerably reduced; and (c) concerns about the long-term performance of geosynthetic liners and related environmental risks can be addressed. This research involves multiple disciplines, including geoenvironmental engineering, sustainable engineering, biology, and computational mechanics. The multi-disciplinary research will provide a unique opportunity to underrepresented groups to participate in research.The proposed modeling tool will combine and simultaneously solve a two-phase flow model, a large-strain explicit mechanical model, and a first-order decay biodegradation model. The model will account for concurrent changes in waste properties to predict coupled processes in landfills. Specifically, the project scope will include: (a) development of a new mathematical model that can account for heterogeneous waste, two-phase flow, and coupled hydro-bio-mechanical processes, and effectively predict spatial and temporal behavior of landfills, (b) model validation with laboratory and field studies to attain a confidence level in the accuracy of the modeling results, (c) prediction of spatial and temporal landfill settlement, slope stability and shear response of liner systems due to coupled processes, (d) assessment of the major system variables that control the performance of landfills based on probabilistic analysis, and (e) application of the tool for forensic investigation of past landfill failures. The project will provide a tool for designing stable and effective engineered landfills and optimizing existing landfills using coupled hydro-bio-mechanical processes.