The Sanitary Landfill
At the end of World War II, urban growth accelerated. With this growth came increased refuse generation. The impacts of open-burning dumps on public health became a concern. Experience in the military with sanitary fill methods and the interests by some local governments in eliminating open dumps led to increased efforts to dispose of refuse in a sanitary manner, but what prescribed a sanitary manner was unknown. Many local governments that bragged about using the “sanitary landfill” method were actually using modified open dumps. Unlike Shakespeare and his rose, a sanitary landfill by any other name ain’t a sanitary landfill.
An example of a landfill of the late 1940s was described in a report prepared by the Sanitary Engineering Research Project of the University of California in 1952.1 The landfill studied in 1949 was described as follows: “Refuse was dropped and spread out over a large area to allow scavengers easy access. At the end of the day pigs were allowed on the spread-out refuse for overnight feeding. The next day the pigs were herded off and the refuse was pushed to the edge of the fill for burning.”Managing municipal solid waste is more than landfilling: publicity, education, engineering, long-term planning, and landfill gas waste-to-energy are specialties needed in today’s complex environment. We’ve created a handy infographic featuring 6 tips to improve landfill management and achieve excellence in operations. 6 Tips for Excellence in Landfill Operations. Download it now!
The reasons for changing this practice are obvious. Open burning of refuse created air pollution. Allowing pigs to eat raw garbage was not a sanitary practice. If open burning was not practiced to conserve space, compaction would be needed, but how much? Early studies indicated that dumping in surface water and groundwater was not a good idea.2 The open dump was weather-friendly, but could a sanitary landfill be as well? Early work by the United States Army and by solid waste pioneers indicated that soil cover was a good idea, but how much and how often? There was no established guidance or frame of reference to set minimum requirements for what constituted a sanitary landfill. Clearly, if the open dump was to be replaced by a far more complex but safer method of disposal, the field would need to separate good practices from unacceptable practices to ensure that a sanitary landfill did indeed dispose of refuse in a sanitary manner.
Through the 1940s and ’50s, the number of papers in the literature about sanitary landfills increased. The titles indicated that our knowledge of the sanitary landfill was increasing. The papers connoted a growing awareness of settlement, gas generation, and fires in sanitary landfills—the first hints about the potential of groundwater contamination.
The commitment of the US Public Health Service (USPHS) to provide national leadership to eliminate open-burning dumps and replace them with sanitary landfills also served as the basis for a broader national strategy to improve the management of refuse. Therefore, the stage was set for agents of change to create a new technology: the sanitary landfill.FONT>
In 1949-50, research by the USPHS, in cooperation with the State of North Dakota Health Department and the City of Mandan, ND, concluded that the operation of a sanitary landfill in extreme winter conditions was entirely feasible. Two USPHS sanitary engineer officers, Leo Weaver and Don Keagy, published the results of their findings in a variety of publications.3
The most distinctive characteristic of the sanitary landfill that separates it from all other landfilling and dumping practices is the use of daily cover. In 1955, Ralph Black of the California State Health Department began research on how much cover material was necessary and at what frequency cover should be applied to deal with flies. Over a period of time, working with entomologist A.M. Barnes, their efforts indicated that 2.625 in. of compacted soil would prevent the emergence of flies from a landfill. Operational limitations (compaction equipment would penetrate cover of that thickness), however, led the researchers to recommend that 6 in. of compacted soil would eliminate this operational problem.4
A further conclusion was that since solid waste arrived at a landfill every day with flies in varying stages of development, a cover of 6 in. of compacted soil applied at the end of each working day would be thick enough to deal with the problems of compaction equipment and would prevent emergence of flies from the landfill. These findings served as the basis for establishing the standard for daily cover of 6 in. of compacted soil that exists to this day. Another result from this work was the creation of the cell (one day’s refuse enclosed with daily cover).
In 1953, a joint committee of the USPHS and the American Public Works Association (APWA) published recommended guidelines for refuse collection and disposal practices for a small community.5 The sanitary landfill recommendations reflect how dramatic the change from open-burning dumps to sanitary landfills would be. Key concepts and recommendations include:
• The site dictates design and operations.
• Training of operators is necessary.
• End use should be part of the plan and design.
• The design and operation should be planned as an engineering project.
• No open burning.
• No swine feeding.
• The working face should be kept narrow and covered promptly.
• Surface drainage should be managed to prevent ponding and erosion.
• Compaction should be done in thin layers (2 ft. of loose refuse).
• Control of insects, rodents, and blowing paper should be practiced.
• Scavenging is not recommended.
• An alternate operating area should be set aside for bad-weather operations.
In 1961 the USPHS developed a set of recommended standards for sanitary landfill operations.6 These standards evolved from the 1953 guidelines and indicate the evolution of sanitary landfill concepts. Of note:
• Geology of a site is an important factor in construction, water pollution, and lateral gas movement.
• Refuse should not come in contact with surface water or groundwater.
• A registered engineer should design sanitary landfills.
• No open burning.
• No domestic animals at the site.
• Access should be limited.
• All refuse should be weighed.
• Telephone/radio communications should be provided.
• The working face should be kept small.
• The refuse should be spread and compacted in 2-ft. layers.
• Compacted 8-ft. lifts are preferred.
• At least 6 in. of daily cover consisting of compacted soil should be applied.
• No scavenging at the working face.
• Surface water should be managed to keep it out of the landfill.
• The final cover and the closed site should be managed after closure.
No mention is made of monitoring. These recommended standards were never published in final form by the USPHS. They, however, served as the basis for the USPHS promotion of the sanitary landfill with state agencies and in their training programs.FONT>
In 1965, with the passage of the Solid Waste Disposal Act, the USPHS accelerated its efforts to introduce sanitary landfill practices in the US. USPHS training programs were expanded to provide techniques for closing open dumps and designing and operating landfills to meet the 1961 guidelines. New publications were developed to better explain the sanitary landfill to regulators, designers, operators, and the public. The term refuse was being phased out and replaced with the term solid waste. State governments increased their investments in solid waste management. State solid waste programs, normally a part of state vector-control efforts, began to be formed as separate entities. Using USPHS 1961 guidelines, many states began to establish state regulations.
Even with such dramatic progress, an accepted definition and understanding of what actually constituted a sanitary landfill remained an open issue. Much of this can be attributed to the fact that as we learned more we needed to do more; the evolution was continuing. Landfill gas migration and the possibility of explosions resulted in a need for control measures and eventually birthed a new industry to capture and utilize the gas as an energy source. Studies began to signal that leachate from landfills could contaminate groundwater, resulting in the birth of groundwater monitoring systems for landfills.
Until the early 1970s, the USPHS approach to get states, local governments, and private landfill owners to change to the sanitary landfill had been through research and development, demonstrations of new technological approaches, training, and technical assistance. The USPHS solid waste program was moved to the Environmental Protection Agency (EPA) when it was created in 1970. As an enforcement agency, EPA found the USPHS approach to effecting change inconsistent with its approach. With no enforcement authority over solid waste, EPA interests in solid waste were minimal. As a consequence, from the formation of EPA until 1976, EPA investment in sanitary landfill programs continued to be reduced. The momentum of the 1950s and ’60s almost came to a standstill.
In 1976, Congress recognized that disposal practices were not improving and that federal attention needed to be increased. The passage of the Resource Conservation and Recovery Act (RCRA) directed EPA to develop criteria for classifying open dumps and sanitary landfills. Building on the USPHS criteria of 1961, the materials and information developed by earlier USPHS research and development efforts, and the now-defunct USPHS training programs, EPA issued the congressional-mandated criteria in 1979.7 The content of these criteria reflected the early efforts of the USPHS, but EPA added several significant improvements. For the first time, criteria were proposed for landfill gas migration and groundwater protection. In addition, the introduction of bulk liquids into sanitary landfills was discouraged. But again, with no enforcement authority over solid waste, EPA lacked the enthusiasm to encourage the implementation of the criteria. The limited resources of the solid waste program were directed to the development of the RCRA-mandated and enforceable hazardous-waste regulatory provisions.Managing municipal solid waste is more than landfilling: publicity, education, engineering, long-term planning, and landfill gas waste-to-energy are specialties needed in today’s complex environment. We’ve created a handy infographic featuring 6 tips to improve landfill management and achieve excellence in operations. 6 Tips for Excellence in Landfill Operations. Download it now!