Municipal solid waste (MSW) landfill cover systems have evolved from being merely a soil cap to a multicomponent, nearly impermeable systems providing better control over infiltration and landfill gas (LFG) emissions. Recently, there has been a widespread development of alternative cover systems which addresses the shortcomings of conventional cover systems such as high construction and maintenance costs, susceptibility to damage due to desiccation cracking and freezing, and ineffective control of LFG emissions. Landfills are regarded as the third largest source of anthropogenic methane (CH₄) emissions in the United States. Apart from CH₄, landfills are a significant source of various other gasses such as carbon dioxide, hydrogen sulfide and several other odorous and non-methanogenic organic compounds. The modern engineered landfills typically install gas collection systems in addition to the conventional soil cover to mitigate LFG emissions. However, these systems are not always 100% efficient in capturing all the emissions. Moreover, at the older landfills where installing gas collection systems is not economical and practically feasible, the fugitive LFG emissions is a persistent problem. In this regard, alternative cover systems with wide range of cover materials have been explored to address the fugitive LFG emissions. This paper summarizes the advancements in the MSW landfill cover systems over the years, along with the core mechanisms underlying their function. Then, advancements in the alternative cover systems, including their advantages, are discussed. Finally, the research challenges/opportunities in the field of exploring alternate landfill cover systems are presented.

城市固体废物 (MSW) 垃圾填埋场覆盖系统已从仅仅是土壤盖层演变为多组分、几乎不可渗透的系统，可更好地控制渗透和垃圾填埋气体 (LFG) 排放。最近，替代覆盖系统得到了广泛的发展，这些覆盖系统解决了传统覆盖系统的缺点，例如高建设和维护成本、易受干燥开裂和冻结造成的损坏以及无法有效控制 LFG 排放。垃圾填埋场被视为美国第三大人为甲烷 (CH ₄ ) 排放源。除了 CH ₄, 垃圾填埋场是各种其他气体的重要来源，如二氧化碳、硫化氢和其他几种有气味和非产甲烷的有机化合物。除了传统的土壤覆盖物外，现代工程垃圾填埋场通常还安装气体收集系统以减少 LFG 排放。然而，这些系统在捕获所有排放方面并不总是 100% 有效。此外，在较旧的垃圾填埋场，安装气体收集系统既不经济也不实际可行，溢散填埋气体排放是一个长期存在的问题。在这方面，已经探索了具有广泛覆盖材料的替代覆盖系统来解决逃逸的填埋气排放问题。本文总结了 MSW 垃圾填埋场覆盖系统多年来的进步，以及其功能背后的核心机制。然后，讨论了替代覆盖系统的进步，包括它们的优点。最后，介绍了探索替代垃圾填埋场覆盖系统领域的研究挑战/机遇。