Burning waste for energy purposes is controversial because it may increase the toxicity of the emissions in the form of ash. This is waste that would otherwise go to full U.S. landfills. Many incineration corporations have claimed they were making energy to get status as a utility. At that time utilities were exempt from the right-to-know laws.
I. Incineration: More than Just Burning the Trash
II. Current Waste Management in the United States
III. The Benefits of Resource Recovery through Incineration
IV. Resource Recovery of Plastics
V. Waste-to-Energy Facilities and Their Operations
Incineration: More than Just Burning the Trash
Burning the trash is an old custom in many rural areas of the United States. Even today, the EPA estimates that the burning of private residential trash is a major source of pollution in the upper Midwest. Historically, burning trash and waste was an improvement over leaving it around or just placing it in heaps. Burning the trash reduced its volume and risk. Waste can be a vector for many public health risks, and it can attract vermin. Rats, mice, and other rodents can become vectors for diseases such as bubonic plague and spread the risk of deadly disease deep into human populations. Waste can also be fuel and shelter. U.S. pioneers in the Midwest used buffalo chips (waste) to build sod houses. Dried, this waste could be burned for fuel and heat. This type of waste was the main type of waste, as opposed to today’s chemically enriched, multisubstance, potentially toxic waste stream.
An estimated 14 to 16 percent of the U.S. waste stream is incinerated. It could be more because many industrial and military wastes are incinerated as well. Generally, waste is delivered to the incinerator. The movement of waste itself is peppered with controversies. The waste may have come from long distances, from cities and waste transfer stations. As U.S. environmental consciousness has increased, more people have become interested in where their waste goes and what environmental impact it has. Waste transfer stations can become a local land-use issues and sometimes an environmental justice issue. When landfills become full, waste must wait in waste transfer stations. The waste can be hazardous. Many communities fear that the transfer station will become a permanent waste site, as some in fact have. The waste is delivered by truck, ship, and railroad. Sometimes there are spills of hazardous wastes, with severe environmental and community repercussions. Environmental justice communities may have an overconcentration of poorly regulated waste transfer sites. These sites are where many spills occur. When energy is to be used from the incineration, the waste is taken to an energy recovery facility, where it is burned in combustion chambers or boilers. High combustion temperatures can help most of the waste burn thoroughly. This is one goal of incineration—less ash for disposal. Environmentalists are very concerned with air emissions from incinerators. These facilities have large emissions that can accumulate quickly around the site as heavier particulate matter such as metals falls to the ground. Metals are difficult to burn completely. Much of what the incinerators put out reflects what is put into them. Waste stream control is difficult at best, although improvements in recycling have benefited other waste streams. Older, pre-1970 incinerators burned everything they could fit into them. Parts of older buildings painted with lead paint are still burned as hazardous waste. The lead does not burn and drops down as particulate matter, creating a risk of toxicity, as it did in Flint, Michigan. Combustible, explosive, illegal, and other dangerous materials inhabit the waste stream. Evidence of a crime or environmental impact that is burned is usually less recognizable than when placed in a landfill. Medical wastes can include all sorts of waste, including trace amounts of radioactive material. Many older municipal incinerators in the southeastern United States were placed in African American communities, exposing generations to heavy metals such as lead, mercury, and cadmium for decades. Issues such as this surround the movement of waste generally and incineration of it specifically. Industry claims that modern air pollution control devices include electrostatic precipitators, dry and wet scrubbers, and/or fabric; and that these get out everything dangerous. Cumulative emissions are not measured, although their human and environmental impacts can be large.
Current Waste Management in the United States
To say that waste is managed is an overstatement. The main characteristic of U.S. waste trends is the massive increase in volume. Enormous progress in regulating the waste stream is a primary characteristic of the U.S. waste management approach. Federal government financing of the expensive infrastructure, sometimes inclusive of modern pollution-control and abatement technologies, made it possible for local governments to treat solid wastes. The waste stream of the 2000s is very different from that of 50 years ago. It contains inorganic materials that can create risks for people and for the environment. This has increased the overall controversy of siting and permit renewals for incinerator facilities. It has also moved the debate into the courts. Recently, incinerators in the African American community of urban north Florida from the 1920s until the 1970s provided the basis for a successful $76 million tort settlement for wrongful deaths and other environmental impacts. The plaintiff s are quick to point out that money does not replace lost lives of loved ones. These bitter victories only increase the rancor of this controversy.
The Benefits of Resource Recovery through Incineration
Industry claims that by burning the solid wastes into ash, incineration reduces the volume of waste entering the landfill by approximately 90 percent. Recovering some of the energy from burning waste can produce electricity. This can help offset any potential cost of environmental mitigation. Resource recovery by incineration of wastes is considered so efficient that old landfills are being opened up and that waste then incinerated for its energy potential.
Resource Recovery of Plastics
Plastics have a higher energy value and heat content than most municipal solid waste materials. While making up 7 percent of the waste stream by weight and 20 percent by volume, plastics provide incinerators with 25 percent of the recoverable energy from municipal solid wastes. A pound of polyethylene supplies 19,000 British thermal units (Btu), but corrugated paper packaging provides only 7,000 Btu. The incineration of plastics produces more energy.
Another major issue around the incineration of plastics is the environmental impacts of the emissions. Many plastics contain heavy metals such as lead and cadmium, which can increase the toxicity of the incinerator ashes, thus causing the ashes to be hazardous wastes. If they are emitted into the air, they may fall as particulate matter on nearby land and waterways. Currently, incinerator ashes are not categorized as hazardous wastes and can usually be disposed of in landfills. In some communities this can be a significant issue. When that happens, this ash can back up in waste transfer stations. The waste transfer stations are not designed or sited as terminal places for waste of any kind, much less hazardous waste. A small incineration plant processes approximately 300 tons of waste each day, while a large plant can process about 3,000 tons.
Incinerators can produce enough energy to run an industrial facility or a small community, depending on volume and kind of waste stream.
Waste-to-Energy Facilities and Their Operations
The cost of building a waste-to-energy incinerator is very high. The volume of truck traffic will increase. Depending on the facility’s permit to operate, it may not be approved to accept all wastes. Trucks delivering wastes are required to display signs that indicate the hazards of their waste loads. Economically, resource-recovery incinerators need a reliable, steady stream of high-energy waste or else processing the waste material will cost more energy than it produces.
Incineration is a waste treatment method sanctioned by the government because research is inadequate to prove it unsafe. This lack of science allows potentially dangerous emissions to enter the environment and communities. The effect of the quantity and types of pesticides in the incineration process has yet to be determined and may present an unaccounted exposure vector to nearby populations and environments. Many communities feel that the burden should be on industry to prove that an emission is safe before it is allowed. Currently the burden is on those harmed to prove it is unsafe to a scientific level of certainty, which is quite high. This controversy reopens a more basic question of whether science should control policy. If the scientific methods are underfunded, slow, and not accessible, then environmental policy stagnates. However, political pressure often forces the government to develop new, controversial policies without waiting for the science to catch up. Incineration as an environmental practice by itself may be limited as environmental policy expands to include concepts of sustainability. However, because it uses the energy from waste and diverts waste from landfills, resource recovery from incineration may see new applications. The larger question is what to do with all the waste, how to stop the generation of waste, and how to clean up the waste already here. Controversies will follow each of these questions.
Robert William Collin
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