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In the USA, municipal solid waste (MSW) landfills constitute one of the major anthropogenic sources of methane emissions. In the landfill cover soils employed at MSW landfills, aerobic methane-oxidizing bacteria (MOB) convert CH4 to CO2, thereby partially mitigating the CH4 emissions to the atmosphere. In this study, culture-dependent and culture-independent techniques were employed to evaluate methane oxidation capacity and to characterize the microbial community in landfill cover soil. Microcosms with synthetic landfill gas headspace were used to measure potential methane oxidation rates in landfill cover soil and in methanotrophs-enriched microbial consortia. The results demonstrate that the enriched landfill cover soil supported the growth of a diverse group of methanotrophic and methylotrophic microorganisms, and were dominated by Type I methanotrophs showing positive correlation with CH4 oxidation rates.
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Coal Ash Triggers an Elevated Temperature Landfill Development: Lessons from the Bristol Virginia Solid Waste Landfill Neighboring Community
Landfills for disposing of solid waste are designed, located, managed, and monitored facilities expected to comply with government regulations to prevent contamination of the surrounding environment. After the average life expectancy of a typical landfill (30 to 50 years), a large investment in the construction, operation, final closure, and 30-year monitoring of a new site is needed. In this case study, we provide a holistic explanation of the unexpected development of elevated temperature landfills (ETLFs), such as that in the city of Bristol (United States) on the border of the states of Virginia and Tennessee, including the initial role played by coal ash. Despite the increasing frequency of ETLF occurrence, there is limited knowledge available about their associated environmental problems. The study uses mixed (qualitative, quantitative, and mapping) methods to analyze (1) the levels of odoriferous reduced sulfur compounds, ammonia, and volatile organic compounds (VOCs) emitted, (2) the ratio of methane to carbon dioxide concentrations in five locations, which dropped from unity (normal landfill) to 0.565, (3) the location of gas well heads with gradients of elevated temperatures, and (4) the correlation of the filling rate (upward of ~12 m y−1) with depth for registered events depositing coal ash waste. The work identifies spatial patterns that support the conclusion that coal ash served as the initiator for an ETLF creation. The case of the city of Bristol constitutes an example of ETLFs with elevated temperatures above the regulatory United States Environmental Protection Agency (EPA) upper threshold (65 °C), having alongside low methane emissions, large production of leachate, land subsidence, and a large production of organic compounds. Such landfills suffer abnormal chemical reactions within the waste mass that reduce the life expectancy of the site. Residents in such communities suffer intolerable odors from fugitive emissions and poor air quality becomes prominent, affecting the well-being and economy of surrounding populations. Conclusive information available indicates that the Bristol landfill has been producing large amounts of leachate and hazardous gases under the high pressures and temperatures developed within the landfill. A lesson learned, which should be used to prevent this problem in the future, is that the early addition of coal ash into the landfill would have catalyzed the process of ETLF creation. The work considers the public health risks and socioeconomic problems of residents exposed to emissions from an ETLF and discusses the efforts needed to prevent further incidents in other locations.
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- PAR ID:
- 10550122
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Environments
- Volume:
- 11
- Issue:
- 9
- ISSN:
- 2076-3298
- Page Range / eLocation ID:
- 201
- Subject(s) / Keyword(s):
- VOCs landfill public health pollution climate change coal ash
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/environments11090201
