The last time a survey was done (2003), the US EPA determined that the average American threw away an average of 4.5 pounds of municipal solid waste every day. Now that America’s population has reached the 300 million mark, this comes to approximately 675 thousand tons per day generated by American residents, individuals, businesses, and institutions.

By Daniel P. Duffy

The big surprise of this survey was that this per capita disposal rate had remained unchanged for over a decade after years of steady increases running parallel with increases in real personal wealth. After increasing steadily since the surveys began, this per capita average has not changed since 1990, thanks  to more efficient packaging, manufacturing, and construction methods. These source reduction efforts (longer-lasting and more durable goods, products and packaging that have been redesigned to use less materials, etc.) have been the single most important change affecting the landfill and waste management industry. Without them, the per capita rate of waste generation would have continued at its previous pace and per capita waste generation would be equal to or higher than 5 pounds per day.

However, nonmunicipal solid waste disposal rates continue to increase. In fact, municipal solid waste accounts for only a small fraction of the total wastestream. The rest is industrial refuse, including mine tailings, agricultural waste, dewatered municipal sludge, construction debris, and exotic materials like “pickle liquor,” an acid solution used to clean steel. This other wastestream continues to grow, especially in the area of coal combustion byproducts. In accordance with the mandates of the clean coal initiative, coal fired energy plants have achieved higher and higher rates of pollutant removals from their exhaust stacks. These byproducts include ash, gypsum, and other materials that need to be landfilled.

These are the two trends—the relative lack of growth in traditional MSW disposal and the increase in industrial waste disposal—that are having the greatest impact on the landfill industry and the economics of waste disposal. This article will focus on the first trend and examine why this flattening of demand is occurring, along with its consequences for the municipal solid waste management industry.

Landfill And Hauling
For those of us who remember that trash barge sailing up and down America’s East Coast back in the 1980s because it supposedly couldn’t find a home for its load of garbage, it always comes as something of a pleasant surprise to realize that overall landfill capacity (as measured by years of remaining landfill operating lifetime) has actually increased. The amount of waste disposed of in landfills is at about 118.5 million tons per year or about 57% of the total wastestream. Combustion (16%) and various kinds of recovery such as recycling and composting (27%) account for the rest. The rate of landfilling is down from a peak of over 81% of the total wastestream in the early 1980s. Since this time, the amount of waste sent to incinerators has remained fairly steady at 16% of the total, but recycling and composting has increased from almost 10% to 30%. What evidence there is indicates that the rate of recycling may not increase significantly in the future as it gets more difficult and more expensive to increase recycling rates in the face of ever more volatile scrap markets. Local public opposition to the construction of more waste incinerators will act to dampen any increase in incineration. So it can be anticipated with some degree of certainty that the amount of the waste stream disposed of in landfill will remain at roughly 55%. Increases in the amount of waste disposed of in landfills will increase with population increases.

The first trend is the continuing tendency toward larger and larger landfills. Why this has an impact on the landfill business can be shown by a simple geometry example. Assume a perfectly square landfill with an area of 100 acres. Such a landfill would have dimensions of 2,087 feet by 2,087 feet. The peak of the landfill would be located at the center, 1,043 feet from the limits of waste. With a maximum allowable final disposal grade of 25% (4 horizontal to 1 vertical) the peak elevation at the center of the landfill would be only 261 feet high. Such a pyramid shaped landfill would have an above-grade volume of a little over 14,000,000 cubic yards (or 140,000 cubic yards per acre). Now take a square landfill 300 cares in size having dimensions of 3,615 feet by 3,615 feet and a maximum height of 452 feet. Its above-grade disposal capacity would be almost 73,000,000 cubic yards (or 243,000 cubic yards per acre). Since landfill costs directly relate to area and landfill profits derive from disposal volume, this large landfill represents a 174% increase in potential profit over the smaller landfill. This is a simplistic analysis for several reasons. It does not include below-grade volumes (which are limited by site hydrogeology) and landfill height will often be limited by local ordinances against visual obstructions, but it does show why larger landfills are preferable. Larger landfills mean fewer landfills, a trend that was kick-started with the advent of Subtitle D and continues to this day.

This is borne out by statistics that show decreasing numbers of landfills while overall landfill disposal capacity increases. While the largest landfill, Fresh Kills in Staten Island, NY, has closed, dozens of others have taken its place. What is new is the fact that many of these large landfills are located in Ohio and other states, not New York. This shipping of waste from the heavily populated coastal regions of the country to the more sparsely populated interior has been made possible by increased use of rail hauling to ship waste cross-country. The costs of rail-hauling have fallen dramatically and are (adjusted for inflation) half of what they were in 1980. Cheaper than trucking and faster than barging, rail-hauling wastes costs between $35 and $45 per ton. Compared to incinerator operating costs in excess of $60 per ton, rail-hauling can be a bargain. Many communities, when faced with politically sensitive or controversial options of building a new landfill or constructing a waste incinerator facility, opt instead for rail-hauling waste out of state or even out of the country. The first step in this process is the truck hauling of collected garbage to a transfer station equipped with a heavy-duty compactor. The compacted waste is loaded into lightweight standard containers that are then placed on the rail flatbeds with a crane for transport to a landfill often hundreds of miles away.

The real estate costs of high population density areas on the East and West Coasts may make development of large landfill prohibitively expensive. However, the relatively cheap real estate of “flyover country” will allow for the continued construction, expansion and operation of large landfills that can for the foreseeable future to allow for relatively inexpensive waste management. The combined coasts of rail-hauling and tipping fees at the destination landfills are still competitive with other options, such as incineration. Politics also plays a role at least as important as economics. Rail-hauling of waste is a classic NIMBY solution, as the waste is quite literally being sent to someone else’s backyard.

Waste Disposal Demand
As mentioned in the introduction, the per capita waste generation rate has held steady for over a decade but the overall rate of waste disposal increases with increased population. However, the supply and demand for waste disposal airspace remains steady, as reflected in the nation’s average landfill tipping fees. After increasing steadily from $9 per ton in the mid 1980s to $30 a ton in the early 1990s, the nation’s average landfill tipping fees remained constant within $1 or $2 of $30 per ton.

However, the number of landfills has decreased steadily during this same time. From a peak of 8,000 landfills in 1988, the current number of landfills is little over 3,000. This represents almost a 63% reduction in the number of landfills. The fact that tipping fees have remained constant shows that available airspace (as opposed to the number of waste disposal facilities) has kept pace with demand. The total amount of waste disposed of after recycling increased from a rate of 137 million tons in 1980 to a peak of 163.5 million tons in 1990 before declining to a relatively steady level of 155 million tons in 2000.

However, waste disposal demand is more properly measured in volume of airspace, not tons of waste. Productivity improvements, as measured by the in-place density of deposited waste, have shown dramatic improvements since the 1980s. Prior to this time, it was a rare landfill that actively compacted its waste or didn’t use large volumes of soil to cover it up. Today, landfills are operated with massive waste compaction equipment especially designed for this work, precision-guided by GPS and laser guidance systems.

Uncompacted waste deposited by a waste hauling truck has a density of about 15 to 25 pounds per cubic foot (an average of about 0.27 tons per cubic yard). So the mostly uncompacted 137 million tons disposed of in 1980 would require over 500 million cubic yards of airspace (or 310,000 acre-feet). Additional airspace would be required for the heavy use of daily and operational cover soils. Some older landfills had as much as 33% of their volume taken up by dirt. Effective waste compaction operations reduce the volume of deposited waste by 50%, doubling its in-place density to 0.55 tons per cubic yard. Therefore, the 155 million tons of waste disposed of in 2000 would require only 282 million cubic yards of airspace (or 175,000 acre-feet). In addition, the extensive use of tarps and other alternate cover materials radically reduce the amount of airspace eaten up by cover soils. And as the geometric example given above clearly illustrates, larger landfills have orders of magnitude greater disposal volume per area than smaller landfills.

Look for continued and expanded use of waste compaction operations with greater efficiencies provided more by guidance and control systems instead of equipment weight. These new control systems allow for maximum efficiency in equipment operations. Further reductions in airspace needs can be achieved by baling operations that can reduce the volume of deposited waste by 75%, a four-to-one volume reduction ratio. Potentially greater airspace demand reduction can be achieved with bioreactor landfills or landfill mining operations, but these nonstandard landfill operations lie outside the range of this study.

Recycling Markets
The benefits of recycling have come under attack in recent years, just as recycling rates have achieved historic highs. In the 40 years from 1960 to 2000, the amount of recycling has increased from 5.6 million tons per year (6.3% of the total wastestream) to 66.6 million tons per year (30%). The vast bulk of recycled materials are paper and cardboard (32.6 million tons in 1995). So extensive has recycling become that the Chicago Board of Trade has established an online recyclables exchange that connects buyers and sellers of recycled materials across the country.

Individual state recycling rates range from less than 9% to well over 30%. And recycling is not just a “Blue State” thing. While recycling rates are high in New York, New Jersey and most of New England, equally high recycling rates are achieved by Florida, Georgia, Tennessee, and Arkansas. Many states have good old-fashioned bottle deposit laws where consumers can get coins for returned bottles and cans. Almost half the states (primarily in the eastern half of the country) have yard waste bans that prohibit the disposal of grass clippings, brush and other organic matter in landfills. This diverted yard waste usually goes to composting program. Every state except Nevada and the District of Columbia has at least one composting program, with New York having the most programs at 200.

Yet, at its moment of apparent triumph, recycling is being hit by severe criticisms of its basic economics and real need. Summarized in a New York Times Sunday Magazine article entitled “Recycling is Garbage,” these attacks make the following claims: “Since there’s no shortage of landfill space (the crisis of 1987 was a false alarm), there’s no reason to make recycling a legal or moral imperative. Mandatory recycling programs aren’t good for posterity. They offer mainly short-term benefits to a few groups—politicians, public relations consultants, environmental organizations, waste-handling corporations—while diverting money from genuine social and environmental problems. Recycling may be the most wasteful activity in modern America: a waste of time and money, a waste of human and natural resources.”

In response, defenders of recycling counterattack by listing its many direct and indirect benefits: recycling cuts pollution, conserves natural resources, and conserves energy. Properly planned and implemented recycling programs can be cost-competitive with solid waste landfilling and incineration while creating jobs and reducing manufacturing costs.

Recycling for better or worse is now permanently embedded in the fabric of American life. Curbside separation of newspapers, plastic bottles and soda cans has become part of the average homeowner’s weekly routine. Every large city has a materials recovery facility (MRF) capable of mechanically and hydraulically separating large amounts of waste into its basic components (paper, metal, plastic, etc.). Maybe recycling doesn’t make pure economic sense, but since politics remains such a large part of community solid waste planning, recycling will remain a popular waste management option.

Comparisons With International Management
Americans throw more waste away than any other major industrialized nation, with Germany, Italy, and Spain having per capita disposal rates half that of the United States. Only Japan throws away a higher percentage of waste as paper and cardboard with “miscellaneous” being the most common waste category for most other countries. At nearly 60%, the amount of waste combusted by Japan greatly exceeds that of the United States, with American combustion rates lower than anyone except Italy, Spain, the United Kingdom, or Canada. Surprisingly, America’s landfill disposal rate is in the middle of the pack and is exceeded by the United Kingdom (90%) and Canada (80%). Even more surprising is that America’s recycling rate is the highest of major industrial countries, with only Switzerland (25%) and Japan (20%) coming close. However, America’s composting rate is mediocre and far exceeded by Spain (18%) and France (10%).

If a pattern emerges from this data, it is that advanced industrial countries with sufficient unused land area can rely more on landfilling (Canada and the United Kingdom) or composting (Spain and France), while those without available land utilize combustion (Japan). The more balanced approach used by America (landfilling, recycling and combustion) reflects our diversity in population density and land utilization. While the northeast corridor approaches European and Japanese population densities, the interior of the country is under populated compared to any European area outside of the eastern European steppes. As such we see marked regional differences in American waste disposal strategies.

Alternate Technologies
So what are the wild cards that would throw all these predictions and trends into the ash heap? First and foremost is the newly developed technology of thermal depolymerization (aka ‘turkey guts into oil”). Thermo-depolymerization (TDP) is a technology that converts organic waste materials into natural gas, fuel oil, and minerals by using intense heat and pressure. It basically accelerates the Earth’s natural process that turns buried dinosaur carcasses and prehistoric forests into the deposits of fossil fuels that we are mining millions of years later. Organic wastes are heated to 500°F at pressures of 600 pounds per square inch for 15 minutes to an hour. During this stage, the waste’s polymers begin to break down and their long molecular chains disassociate. The pressure is suddenly dropped by the venting of steam (whose heat is recaptured to help run the process). Increased heat followed by distillation results in the production of natural gas, crude oil, fertilizer, and water.

This is actually a refinement of an older technique that has been around for over a quarter century. Where the new process differs is that it substitutes the addition of water under high pressure for the old method of straightforward incineration. Proponents of the process claim 85% energy efficiency for the process with matching levels of high productivity. Any organic waste outside of nuclear waste and scrap metal can be fed into the process. It doesn’t have to be turkey gizzards or the parts of any other animal or plant. For example, 100 pounds of scrap tires (once the steel belting has been removed) could yield 44 pounds of crude oil. Its developer claims that once economics of scale are achieved by multiple plants, the process could produce crude oil at a cost of $10 per barrel.

If the champions of TDP are right, the amount of agricultural waste produced each year in the United States could be converted to an amount of oil equal to the amount imported from the Middle East. Over three-fourths of municipal solid waste consists of organic materials (paper at 39.2%, yard waste at 14.3%, plastics at 9.1%, wood 7.1%, and food waste at 6.7%). That’s a total of 159 million tons per year out of a total waste stream of 208 million tons. Much of this is already diverted from landfills into composting programs as part of multi-state yard waste bans. More is diverted to recycling programs. After recycling and composting, the amount of organic wastes actually going to landfills is 113 million tons per year. If organic wastes are kept out of landfills by some combination of composting, recycling, and TDP, what is left of the waste stream is only 39 million tons of nonrecycled metals, glass, and other wastes. That’s a 71% reduction in the 152 million tons per year currently going into landfills.

However, there has not yet been an independent third-party review of these claims.  One ton of crude oil is equal to 7.3 barrels, making the weight of one barrel equal to 274 pounds. Using the same ratio given for scrap tires, 274 pounds of crude oil would require 623 pounds of organic waste (0.31 tons). At projected production costs of $10 per barrel (274 pounds of crude, or 623 pounds of waste), this cost is equivalent to a tipping fee of over $32 per ton. While the resale price of the crude oil will greatly offset these costs, it remains to be seen if TDP can compete with landfills that charge tipping fees under $20 per ton. Furthermore, turkey guts, offal and other organic wastes aren’t free. For example, if turkey waste can be used as animal feed (without fear of mad cow disease) it has to be purchased at a cost of $30 to $40 per ton, adding $15 to $20 per barrel to the cost of the oil. Facilities using this system will also have to compete with recyclers and composters for their waste. This makes the actual cost of operations hard to predict. Odor controls and exhaust scrubbers will also increase operating costs. So the jury is still out on TDP. It could radically change the waste industry overnight, virtually eliminating the need for landfills. Or it could be the waste industry’s version of cold fusion.

Summary and Conclusions
For the foreseeable future the following trends should dominate the waste disposal industry:

• More than sufficient landfill capacity will be provided by fewer and large landfills primarily located in the less populated interior of the country but servicing multi-state regions via rail haul transport.
• Demand for disposal capacity will remain relatively flat due to continued utilization of waste combustion, recycling, and composting.
• Any increases in waste disposal demand will result from population increases, not increases in per capita disposal rates that normally accompany increases in real personal wealth.
• Trend lines indicate that recycling has peaked and rates of recycling have leveled off. It will be difficult, for economic reasons, to increase the current rate of recycling. It will be difficult, for political reasons, to decrease it.
• The waste industry will see real growth in nonmunicipal solid wastestreams such as coal combustion byproducts created by technologies that will greatly reduce the pollutants in coal emissions.
• Regional differences in waste management approaches will become more pronounced with each region finding a different optimum strategy based on population, real estate costs, and land-use patterns.
• Radical changes may occur as a result of new technological breakthroughs, but their adoption will be made less likely (even if they occur at all) by competition with other, well-established waste management methods.

Daniel P. Duffy, PE, is an environmental engineer employed by URS Corp. in Akron

MSW - November/December 2006

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