Service life of geosynthetic liners for containing municipal solid waste leachate and wastewater with and without per- and polyfluoroalkyl substances

城市固体废物（MSW）、垃圾填埋场渗滤液和污水通常含有全氟烷基和多氟烷基物质[PFAS]。PFAS具有显著的健康影响（例如，癌症）。它们是“永久的化学物质”，在食物链中生物积累，最终到达人体。PFAS必须被控制几十年到几百年。安大略要求小型和大型垃圾填埋场的城市固体废物填埋场塑料衬垫（土工膜）分别使用150至350年。然而，没有普遍接受的方法来选择衬垫，以满足这些要求或污水和采矿泻湖的不太严格的要求。因此，存在失败。于2021年，我调查了5个班轮故障，包括一个使用3年的采矿泻湖班轮排放了1，100万升污染水，另一个使用15年的班轮排放了8亿升污染液体。该研究计划将通过开发来解决内衬故障的根本原因：对影响内衬系统功效的因素的基本理解，可靠估计其使用寿命（有效容纳流体的时间）的方法，未来设施的设计指南，以及评估现有设施何时可能发生故障的方法，以便采取措施防止污染。这项拨款资助的研究将确定用于容纳PFAS的衬垫系统的三个主要组件的功效和使用寿命。这将需要考虑应用和材料，如下所示。 北方社区相对较新的污水塘由于内衬无法承受气候变化的影响（如永久冻土融化）而导致内衬失效，泄漏过多。这项研究将评估当前和替代的衬垫系统，并制定选择适当衬垫的指南。 多组分土工合成粘土衬里联合收割机将塑料衬里和粘土层结合在一个产品中，可以在衬里的塑料组分的（未知的）使用寿命内将泄漏最小化到可忽略的水平。这项研究将首次研究它们的使用寿命。如果使用寿命足够长，它们是偏远社区泻湖的成本效益衬垫，也是许多采矿泻湖和城市固体废物填埋场衬垫系统的一部分。该研究将使用独特的设施，包括一个全尺寸的内衬测试场地和实验室设备，这些设备将能够在模拟现场条件下测试整个内衬系统。这项研究将减少水污染，并使加拿大设计顾问、监管机构、制造商、设施所有者/运营商、原住民和公众受益，他们都将能够更多地依赖这些衬垫系统，并提高加拿大在环境可持续发展方面的国际竞争力和声誉。该研究将培养7名博士生，6名硕士生和5名本科生。

Municipal solid waste (MSW) landfill leachate and sewage water typically contain per- and polyfluoroalkyl substances [PFAS]. PFAS have significant health effects (e.g., cancer). They are "forever chemicals" that bioaccumulate in the food chain, ultimately reaching the human body. PFAS must be contained for many decades to many centuries. Ontario requires plastic liners (geomembranes) for MSW landfills to last 150 to 350 years for smaller and larger landfills, respectively. However, there are no generally accepted means of selecting liners that will meet these or the less stringent requirements for sewage and mining lagoons. Thus, there are failures. In 2021, I investigated 5 liner failures, including a 3-year old mining lagoon liner that discharged 11 million litres of contaminated water and another 15-year old liner that discharged 800 million litres of contaminated fluid. This research program will address the root causes of liner failures by developing: a fundamental understanding of the factors affecting the efficacy of liner systems, a method of reliably estimating their service life (how long they will effectively contain fluids), design guidelines for future facilities, and a means of assessing when a failure is likely for existing facilities so action can be taken to prevent contamination. The research funded by this grant will establish the efficacy and service life of the three main components of a liner system for containing PFAS. This will require considerations of both the applications and the materials, as illustrated below. Relatively new sewage lagoons in northern communities leak excessively because of liner failures due to the liners' inability to tolerate the effects of climate change, such as thawing permafrost. This research will evaluate current and alternative liner systems and develop guidelines for the selection of appropriate liners. Multicomponent geosynthetic clay liners combine both a plastic liner and a layer of clay in a single product that can minimize leakage to a negligible level for the (unknown) service life of the plastic components of the liner. This research will provide the first study of their service life. If the service life is adequate, they represent cost-effective liners for lagoons in remote communities, and part of the liner system for many mining lagoons and MSW landfills. The research will use unique facilities, including a full-scale liner test site and lab equipment that will enable the testing of the entire liner system under simulated field conditions. The research will reduce water contamination, and benefit Canadian design consultants, regulators, manufacturers, facility owners/operators, First Nations, and the general public who will all be able to place greater reliance on these liner systems and enhance Canada's international competitiveness and reputation for environmentally sustainable development. The research will train 7 PhD, 6 MASc and 5 undergraduate students.