University of Florida, Department of Environmental Engineering Sciences, College of Engineering, Gainesville, FL 32611, USA.
US Environmental Protection Agency, Office of Research and Development, National Risk Management Laboratory, Cincinnati, OH 45268, USA.
Waste Manag. 2022 May 1;144:49-56. doi: 10.1016/j.wasman.2022.03.009. Epub 2022 Mar 17.
Municipal solid waste incineration (MSWI) ash is often managed through co-disposal with unburned wastes in landfills, a practice previously reported to result in enhanced leaching of pollutants (e.g., heavy metals) in landfill leachate. The objective of this study was to evaluate the effect of co-disposed unburned wastes on per- and polyfluoroalkyl substances (PFAS) in MSWI ash landfill leachate. Leachate was collected from four landfills containing MSWI ash, either as a sole waste stream or co-disposed of with sewage sludge and MSW screenings. Samples of ash and unburned materials were collected and assessed separately for leachable PFAS in the laboratory. All samples were analyzed for 26 PFAS. Results showed that greater ash content was associated with lower leachate PFAS concentrations. The pure ash monofill exhibited the lowest PFAS in landfill leachate (290 ng L) while the landfill contained a large amount of unburned waste had the highest PFAS (11,000 ng L). For laboratory leaching tests, average ∑PFAS concentration in lab ash leachate (310 ng L) was 10 and 24 times lower than observed in lab sewage sludge leachate (3,200 ng L) and lab MSW screenings leachate (7,500 ng L), respectively. Leachate from the ash-only landfill had ∑PFAS concentration similar to what was measured in the ash itself. On the contrary, ∑PFAS concentration in co-disposal landfill leachates were similar to those in PFAS-rich unburned waste itself, regardless of the percentages of landfilled unburned wastes. We hypothesize that leachate generated in co-disposal scenarios preferentially flows through PFAS-rich unburned materials and that biotransformation of precursors enhanced by unburned waste degradation further contributes to higher concentrations of terminal PFAS in ash co-disposal sites. Landfill operators should expect PFAS in leachates to be higher when PFAS-rich unburned wastes are disposed of alongside MSWI ash, even if the unburned fraction is small.
城市固体废物焚烧（MSWI）灰通常通过与未燃烧废物在垃圾填埋场中共同处置来管理，先前的研究报告表明，这种做法会导致垃圾渗滤液中污染物（例如重金属）的浸出增加。本研究的目的是评估共同处置未燃烧废物对 MSWI 灰填埋场渗滤液中全氟和多氟烷基物质（PFAS）的影响。从四个含有 MSWI 灰的垃圾填埋场收集渗滤液，这些垃圾填埋场要么仅作为废物处理，要么与污水污泥和 MSW 筛渣共同处置。分别收集灰分和未燃烧材料的样品，并在实验室中评估其可浸出的 PFAS。所有样品均分析了 26 种 PFAS。结果表明，灰分含量越高，渗滤液中 PFAS 浓度越低。纯灰分单填区的填埋渗滤液中 PFAS 含量最低（290ng/L），而含有大量未燃烧废物的填埋场的 PFAS 含量最高（11,000ng/L）。对于实验室浸出试验，实验室灰分浸出液中平均∑PFAS 浓度（310ng/L）分别比实验室污水污泥浸出液（3,200ng/L）和实验室 MSW 筛渣浸出液（7,500ng/L）低 10 倍和 24 倍。仅含灰分的垃圾填埋场的渗滤液中∑PFAS 浓度与灰分本身的测量值相似。相反，共同处置垃圾填埋场渗滤液中的∑PFAS 浓度与富 PFAS 未燃烧废物本身的浓度相似，而不管填埋的未燃烧废物的百分比如何。我们假设，在共同处置情况下生成的渗滤液优先流经富 PFAS 的未燃烧废物，并且未燃烧废物降解增强的前体生物转化进一步导致灰分共同处置点末端 PFAS 浓度升高。当富 PFAS 的未燃烧废物与 MSWI 灰一起处置时，填埋场运营商应预计渗滤液中的 PFAS 会更高，即使未燃烧部分很小。
