Solid Waste Disposal Trends

Edward W. Repa

Few things have changed the way solid waste has been managed in the United States more than the Resource Conservation and Recovery Act (RCRA). Since its passage in 1970, RCRA, too, has been changed, including the addition of Subtitle D. This single piece of legislation has affected virtually every aspect of landfill man- agement, and the way Americans dispose of their solid waste.

Waste Volumes Based on the best available information, the total amount of solid waste managed in non captive facilities in 1997 to 1998 was 437 million tons per year. This includes 102 million tons recycled, 299 million tons landfilled and 36 million tons incinerated.

The true amount of solid waste managed probably was higher because none of the data sources were complete (e.g., states not reporting information or missing facility surveys), although these factors might be offset by states that include construction and demolition (C&D) debris or automobiles as part of their recycling calculations.

Generally, the percent of waste managed by a specific method did not change as dramatically as the volumes. Landfilling was the predominant waste management method, accounting for 69 percent of the waste generated. Recycling accounted for 23 percent, and incineration 8 percent.

Historical trends for waste volumes generated and disposed of were not available because the definition of solid waste varied in the literature.

Landfill Numbers In the early 1970s, the U.S. Environmental Protection Agency (EPA), Washington, D.C., estimated there were approximately 20,000 municipal solid waste (MSW) landfills in the United States. This was probably an overestimate because few records had been maintained by states. In 1986, the EPA found 6,034 active MSW landfills and predicted that number would decline by more than 2,000 by 1992 as a result of the new regulations.

Since 1986, a number of state regulatory agencies have been surveyed to determine how many landfills were operating. Data collected from 1988 to 1997 showed that the number of landfills ranged from a high of 7,575 in 1988 to a low of 2,514 in 1997.

Individual state data showed a wide variability among surveys that could not be attributed to normal yearly variances. Although some of the fluctuations may be attributed to landfill closures and openings, most of it couldn't be explained.

One reason for such variations may be the survey method. Some states may include all landfill types in their response, while others only include MSW landfills.

Nevertheless, the number of U.S. landfills has declined significantly during the past 10 years. From 1988 to 1991, the number of MSW landfills declined 24 percent, or by 1,849 landfills, while from 1991 to 1995, the number declined 49 percent, or by 2,833 facilities.

The rate of decline leveled off after 1995. Only 379, or 13 percent, of MSW landfills closed during this time. Overall, from 1988 to 1997, the total number of MSW landfills dropped 67 percent, or by 5,061, leaving 2,514 landfills remaining.

Between 1988 and 1997, none of the states reported a net increase in the number of MSW landfills. However, between 1991 and 1997, Michigan and Pennsylvania reported increases in their total number.

The states that experienced the greatest declines in the number of MSW landfills between 1988 and 1997 included Texas (-748), Wisconsin (-727), Alaska (-404) and Virginia (-256). All other states saw declines of less than 200 landfills.

The states with the smallest decline for the 10-year period included Delaware (0), Rhode Island (-6), Hawaii (-7) and Minnesota (-8). However, only Delaware reported the same number of facilities (3) in all five surveys. This anomaly was attributed to the state maintaining control of all waste disposal capacity through the Delaware Solid Waste Management Authority.

The dramatic change in the number of landfills in the United States over the past 10 years is primarily attributable to RCRA's Subtitle D, which became effective in October 1991. The greatest declines in the number of landfills occurred prior to 1995 and have leveled off since. The number of landfills should remain basically the same unless major regulations are adopted nationally.

Landfill Capacity State landfill capacity has generally increased during the past 13 years. Between 1986 and 1991, 13 states (Connecticut, Georgia, Kentucky, Massachusetts, Mississippi, New Jersey, New York, Oklahoma, Pennsylvania, Rhode Island, Vermont, Virginia and West Virginia) reported less than five years of capacity.

Today, all the reporting states have more than five years of capacity. Only two states (Massachusetts and Vermont) consistently reported less than five years of capacity during the 13-year period. During this time, disposal capacity in both states fluctuated between less than five years and five to 10 years of capacity.

National landfill disposal capacity follows the same trends as the state capacity data. According to Washington, D.C.-based National Solid Waste Management Association (NSWMA) data, the national disposal capacity was approximately 11 years in the late 1980s. By the mid-1990s, national disposal capacity increased to about 14 years and presently stands at more than 16 years, according to Chartwell Publishers, Alexandria, Va.

Based on this information, most states appear to be adequately addressing their solid waste disposal capacity needs. This was accomplished through a variety of methods including siting new landfills and incinerators, increasing recycling rates and relying on out-of-state disposal capacity.

Landfill Ownership In the mid-1980s, 83 percent of landfills were owned by the public sector, with this percentage declining substantially in the last few years. Since 1984, public sector landfill ownership has decreased by 23 percent. Conversely, the number of landfills owned by private companies has increased substantially (112 percent), from 17 percent in 1984 to 36 percent in 1998.

The largest increases in private landfill ownership, and conversely, the greatest decreases in public ownership, occurred between 1996 and 1998. Subtitle D caused this, forcing many smaller, publicly owned landfills to close.

The volumes of waste managed in publicly and privately owned landfills followed the same trend as ownership. In 1984, the amount of waste managed by public and private landfills was the same (50 percent public/50 percent private). In 1998, however, the amount of waste managed in privately owned landfills increased to 58 percent while the publicly owned landfills' share declined to 42 percent.

The scores of public facilities closing redirected that waste to private landfills rather than to new publicly owned facilities, which accounts for the shift to private sites.

Tipping Fees The tipping fees used in this report are only from privately owned or operated facilities and represent the spot market price for MSW disposal. Other tip fees exist (e.g. long-term contracted waste, special wastes) and may vary from the spot market price.

The 1998 tipping fee data came from 607 privately owned or operated U.S. MSW landfills. The number of landfills represented in past surveys has changed dramatically since 1982, when less than 65 landfills were surveyed. This survey almost represents an 850 percent increase in the number of facilities represented. Therefore, comparisons and conclusions drawn between older and newer data may not accurately represent actual conditions.

Instead, the historical national average tipping fees were recalculated based on weighted averages for the number of facilities represented in each region in the 1995 survey. Additionally, tipping fees prior to 1985 were not included in the regional data because these fees couldn't be normalized.

The average national tip fee in 1998 was $31.81 per ton, a decline of 1 percent from the 1995 survey. This is the first time the national tip fee declined since NSWMA began tracking tip fees in 1982. Prior to 1998, tipping fees increased approximately 7 percent per year. The change in the national tip fee from 1985 to 1998 was $23.61 per ton, an increase of almost 300 percent. The largest annual increase occurred between 1986 and 1987, when the tip fee rose $5.29 per ton. The smallest year-to-year increases occurred between 1990 and 1992, when the tip fee increased only $1.66 per ton annually.

As with the national tip fees, five of the seven regional tip fees showed a slight decline in 1998 compared to 1995. The largest decrease was in the Northeast region, where the tip fee fell almost $6.50 per ton (almost 9 percent). Only the South and South Central regions showed an increase during this period, with the South increasing 8 percent and the South Central increasing 4 percent. The Northeast region had the highest average tipping fees at $66.68 per ton, while the South Central region reported the lowest average tip fees at $21.02 per ton.

Average national tipping fees always have been less at landfills than at incinerators. In 1982, landfill tip fees were $8.07 per ton and incinerator tip fees were $12.91 per ton, a difference of $4.84. The difference has increased every year since then. In 1998, the average landfill tip fee was $31.81 per ton, and the incinerator tip fee was $58.83 per ton, a difference of $27.02. Landfill tip fees probably will continue to be lower than incinerator tip fees.

In summary, the available data showed the following about U.S. solid waste generation and management:

* The data for the amount of waste being managed off-site were inconsistent and unreliable. The best estimate of the amount of solid waste managed off-site was approximately 437 million tons per year, with the actual amount likely to be greater.

* The number of U.S. landfills declined significantly since the early 1970s because of landfill closures forced by stricter regulatory programs. The number of landfills declined from an estimated 20,000 in 1970 to 2,800 in 1995. The number of landfills remained relatively constant since 1995 and is not expected to change significantly.

* National disposal capacity has increased during the past decade to more than 16 years and probably will increase only when existing capacity is depleted regionally.

* Landfill ownership and the volumes being received at these sites have shifted from the public sector to the private sector. As with the number of landfills, this trend appears to be related to stricter regulations. Whether or not this trend continues cannot be predicted based on the available data.

* Landfill tipping fees increased at a rate of 7 percent annually until 1998, when the fees remained relatively constant at about $32 per ton. This deviation from historical trends is unlikely to continue because many facilities have announced tip fee increases.

* Landfill tip fees historically have been lower than incinerator tip fees, and this trend is not expected to change in the future.