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History
A Brief History of Solid Waste Management in the US, 1950-2000 |
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Part 7a: Landfill Gas Odors/Fires, Explosions, and Kilowatts. The evolution of sanitary landfills was reviewed in Parts 2 and 3 of this series. From the review of early literature and interviews with a number of landfill gas (LFG) pioneers and continuing leaders, the author concludes that LFG management in North America had three stages of development: odors/fires, explosions (migration), and energy recovery. Odors/fires and explosions will be discussed in this issue; LFG-to-energy will be discussed in the next issue. Links to other parts of our series may be found at the end of this article. Prior to using sanitary landfills, odors were a common concern at the open-burning dumps in use in the 1940s-1960s. One of the early attributes of the sanitary landfill that added to their acceptance was the effectiveness of early cover in reducing odors. While the open-burning dump was a gas generator, until cover material was used, the major concerns remained odors and fires. Only later did migration become an issue. There is a paucity of information about LFG in the early literature (pre-1970). Much of what was published has been lost over time. Fortunately, Public Works and Engineering News Record have copies of all their issues. Some early information reviewed here is very dependent on their archives. In addition, as an awareness of LFG began, since there were no solid waste publications or solid waste management associations, the flow of experience and information across North America was very limited. This resulted in managers of disposal facilities being on their own to deal with all issues associated with their facilities. Two examples make this point. A 1939 paper about gas sampling,1 and a 1940 paper about the formation and composition of LFG2 that might be considered significant remained virtually unknown. From 1940 to 1946, information was fairly limited because of World War II. It was after this war that we began to see more attention focused on gas from landfills. Odors and Fires: 1940-1950 While we may associate odors to some degree to LFG, in the 1940s-1950s, foodwaste - as a major component in solid waste - was considered the main culprit of odors, and likely so. Since the open dump was the disposal facility of choice, the lack of cover permitted LFG to escape unnoticed, and migration was not a concern. In one case, fires were attributed to vapors from wastes igniting by spontaneous combustion; there was no mention of LFG.3 In 1947, Bailer reported that a fire in a sewer manhole was traced back to the migration of LFG into a sewer line buried beneath the fill.4 In this same article, explosions and property destruction at a number of locations were attributed to LFG. On the other hand, in 1950, the report that put the Los Angeles County Sanitation Districts (LACSD) into the sanitary landfill business did not address gas as an issue.5 This diversity of views clearly demonstrates the lack of a universal understanding that disposal sites could generate gas that may cause problems. In 1954 the fluctuations of temperature and the composition of gas present in a "sanitary fill" were reported by a University of Southern California study.6 The paper also reports the development of a device to sample gas in a landfill and the use of an Orsat gas analyzer. In the LA Basin, an awareness of LFG was emerging. Dunn, in a 1957 paper, reported the use of LFG as an odor control measure at a landfill in the state of Washington.7 Vents were designed and installed to burn the gas. It appears that a body of knowledge about LFG was beginning to emerge. Terms to identify the difference between dumps and sanitary landfills began to emerge in the 1950s. Sanitary fill, sanitary-fill, and sanitary land-fill were common terms used. During the late 1950s, thanks in part to the establishment of the sanitary landfill program of the LACSD, the principles of the sanitary landfill began to emerge, especially the two basic principles of sanitary landfilling: compaction and daily cover. Migration: 1950-1970 Eliassen et al., in a 1957 paper, noted the widespread adoption of basic sanitary landfill principles and, as a result, the LFG generation and migration to adjacent areas when cover materials lacked porosity.8 The paper further noted that explosions had occurred within structures adjacent to landfills as a result of LFG migration. However, the significance of LFG generation and migration and its potential hazard remained unappreciated. In 1959 the American Society of Civil Engineers published its landfill practices manual.9 This manual dealt with many sanitary landfill practice principles, yet LFG was not addressed. Similarly, in 1961 the United States Public Health Service published recommended standards for sanitary landfill operations, but no mention of monitoring or controlling LFG.10 Here were two major players, in what we now know as solid waste management/environmental engineering, issuing "national" guidelines for sanitary landfills, yet neither address monitoring or managing LFG. When did the awareness of migration and its possible explosion hazards finally result in recognition of a need for monitoring and management? In 1965 a young boy playing in a cave he had dug in his backyard was burned in a flash fire when he attempted to light a candle. Investigations by the Los Angeles County Engineer (LACE) attributed the presence of gas from the landfill in Monterey Park. This led to a study by this office of general landfill practices in Los Angeles County. The result of the LACE study prompted an expanded investigation, partially funded by the newly established USPHS Office of Solid Waste, to develop criteria for sanitary landfills.11 Ten sites were studied for gas composition and movement, a variety of soils were analyzed for suitability as barriers, and a variety of barrier and control devices were designed and installed in three sites. This early work was an important part of the initial development of LFG control procedures. In 1965, the LACSD received a complaint about roses dying at a neighboring residence near the Palos Verdes Landfill. Investigations revealed that LFG had migrated as a result of a sand lens that ran through the landfill site and the areas around the landfill. An inceptor trench was installed to vent the gas. This incident alerted the LACSD to a potential problem at all of its sites. The turning point that resulted in the need to monitor and control offsite migration was an incident that occurred in 1969 at Winston-Salem, NC. An explosion at a national guard armory killed three guards, seriously injured 12, and caused minor injuries to another 25. The cause of the explosion was traced to LFG migrating from a landfill approximately 100 ft. from the armory.12 LACE sent Charley Brisley to Winston-Salem to gather information. This visit resulted in a series of briefings, by Brisley to local governments, landfill owners, and operators in the LA Basin about the hazards of LFG migration. Subsequent to that, LACE, with funding assistance from the USPHS Office of Solid Waste, began studies of LFG generation. Following the Winston-Salem incident, LFG monitoring and migration control became a part of sanitary landfill practice. This occurred over time but was not universally done. Special equipment for LFG capture, transmission, and destruction began to emerge. The installation of LFG migration control systems, plus other factors, eventually led to an examination of LFG as an energy source. The second part of this article will discuss the emergence of LFG-to-energy systems and the maturation of monitoring and control. Note: It is impossible to develop a straight-line path for the development of LFG management. Rather, many isolated efforts and incidents gradually built up a universe of information and awareness of the need to monitor for, and manage, LFG to protect the public from the threat of explosions. Without question, the organizations in the LA Basin were the founders of what is now a full-fledged practice within the field of solid waste management. References
H. Lanier Hickman Jr. is a member of MSW Management’s Editorial Advisory Board. To read the other parts in this feature please click on the relevant links below:
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