New incinerator emission rules impact waste management decisions

Nov. 27, 2006
If so, you should know the effect the new hazardous waste incinerator air emission rule will have on your waste management decisions.

In 1981, EPA promulgated the first set of technical regulations that governed the incineration of hazardous waste. This rule was fairly simple. It required hazardous waste incinerators to destroy at least 99.99 percent of the organic constituents of the hazardous waste, keep particulate matter emissions below 180 mg/dry standard cubic meter (dscm), and limit chlorine emissions to less than 1.8 kg/hr or 99 percent removal (whichever is higher). In 1984, Congress passed amendments to the Resource Conservation and Recovery Act giving EPA the authority to include such restrictions as necessary in permits to protect human health and the environment--the so-called "omnibus" authority. Because EPA had this "omnibus" authority, they controlled hazardous waste incinerator emissions primarily through individual permits rather than through the development of new regulations. As a result, permit conditions vary significantly from one jurisdiction to another.

In 1991, EPA developed new regulations governing the burning of hazardous waste in boilers and industrial furnaces. These rules contained limits on carbon monoxide (100 ppm), particulate matter (180 mg/dscm), feed rate limits for certain metals, feed rate limits for chlorine, and in certain instances, risk based limits on dioxins and furans. Most of these limits have been incorporated into hazardous waste incinerator permits using the "omnibus" authority.

In 1996, EPA's Office of Solid Waste began developing revised air emission regulations for hazardous waste incinerators and certain industrial furnaces. These revised standards will be based on the Maximum Achievable Control Technology methodology contained in the 1990 amendments to the Clean Air Act. This law requires EPA to survey each industry to determine what technology will result in the best available control of air emissions. Congress gave EPA specific instructions to set new emission standards on a pollutant-by-pollutant basis at the average of the best 12 percent of existing sources for that pollutant. EPA is expected to finalize these regulations in early 1999.

Maximum Achievable Control Technology requirements

Although the revised air emission standards for hazardous waste incinerators will not be final until 1999.

With the exception of particulate matter and carbon monoxide, it is difficult to compare the old and revised standards directly. Revised emission standards are based on concentration in the stack, while the old standards relied on either feed rate limits (metals), total loading to the environment (chlorine), or risk assessments. Under the old standards, each of these parameters took into consideration the physical location of the facility, the air flow rate in the stack, the height of the stack, and other site-specific parameters to determine emission limits in their permits. With the revised standards, hazardous waste incinerators will have to meet the same concentration standards unless site-specific risk assessment shows that these levels will harm human health and the environment--"omnibus" authority again. However, there is little doubt that the revised standards will be stricter than the old standards and will force facilities to make choices on how to meet the revised standards.

Types of upgrades needed

Because of the way the emission standards were developed, some facilities should already meet them. In addition, since individual permits vary in their restrictions, facilities with more restrictive permits may need fewer modifications. However, since the emission standards were developed on a pollutant-by-pollutant basis, many facilities will need at least some modifications to meet the revised standard.

The revised emission standards are based on technology. Although EPA defines the technology that is expected to meet the standards, they will not require the installation of specific equipment. They only specify that each incineration unit meet all the requirements. Simple installation of the designated technology may not be sufficient to meet the revised emissions standards. Rather, the facility must show that the new equipment meets emissions standards before the facility can continue to operate. The practical problems of meeting all standards simultaneously make this more difficult.

Most likely, facilities will opt to add stages to their current air pollution control devices to tackle individual problems. For instance, if a facility has problems meeting the new mercury or dioxin standards, they may choose to inject activated carbon or run the flue gas through a fixed bed. Both of these technologies are available but are not without problems. Fixed beds of activated carbon must be kept below the autoignition temperature to prevent a fire. Both create additional waste that requires treatment by incineration, recycling, or disposal in a hazardous waste landfill. Thus, the choices are not always simple, straightforward, and easy to engineer.

Continuous monitors

One of the more difficult choices facing facilities is meeting the requirement to install and operate a continuous emissions monitor for particulate matter. While there is considerable debate regarding whether particulate matter monitors are sufficiently developed for use as a compliance tool in the United States, it appears likely that they will be required in the near future. If a continuous monitor is required, you will have to choose which monitor best suits your needs.

There are two primary factors a facility will need to consider when choosing the type of monitor to be installed--whether your stack is wet or dry and the variability of your waste streams. Most of the commercially available monitors should work on a dry stack. Monitors based on in situ light scattering have the advantage of being the least expensive, the easiest to install, and requiring the least amount of maintenance. The light scattering monitors have the disadvantage of being influenced by particle size, shape, and color.

Facilities that have significant swings in particle characteristics may find that multiple calibrations of a light scattering monitor are necessary. Not only does this increase the initial cost of calibration; it also increases the complexity of complying with the standard. These facilities may want to consider beta gauge monitors because they directly measure mass and are not influenced by particle characteristics. However, beta gauges have higher maintenance requirements and are more expensive. For facilities with dry stacks that have fairly constant particle characteristics, the choices will be straightforward and relatively inexpensive. For others, the choices will be limited and the cost will be higher.

The choices for facilities with wet stacks are more restricted. The in situ light scattering monitors will not work on a wet stack because the monitors read entrained water droplets as particulate matter. Thus, these facilities are restricted to either an extractive light scattering monitor or a beta gauge. Both types are much larger and more expensive.

However, at least one of the extractive light scattering monitors has relatively low maintenance requirements. Like the in situ light scattering monitors, extractive light scattering monitors are also sensitive to changes in particle characteristics. Thus, facilities with wet stacks and variability in particle characteristics may find that beta gauge monitors are a better choice.

Permitting process

You should expect to be required to install the proper equipment to meet the revised standards and file a pre-certification of compliance within three years from the date of publication of the new rule in the Federal Register.

This pre-certification becomes the new compliance parameters. The facility is then allowed six months to complete the testing of the new equipment and an additional three months to develop a certification of compliance. The facility can then apply for an air permit. At some later time, the regulating agency will issue an air permit. After the air permit has been issued, it is expected that the RCRA permit will be modified to remove the parameters also covered in the new air permit. Thus, there will be an extended period of time when the facility will have two sets of compliance parameters for the same set of pollutants.

EPA understands this and will place in the final rule a statement that the more stringent of the two will apply. Facilities must be careful not to create compliance parameters in their certification of compliance that conflict with their RCRA permit. This could result in a facility being out of compliance no matter what is does. In addition, EPA needs to make the modification to the RCRA permit after the air permit is issued as seamlessly as possible.

Impacts on waste incinerators

The first question any incinerator operator will ask is "Does it make economic sense to upgrade equipment or change operations to meet the revised standards?" Each facility should weigh the costs of upgrading their operations to meet the revised standards with the cost of shutting down operations. However, the questions facing commercial facilities are slightly different than the ones facing captive incinerators.

Commercial incinerators

To properly evaluate their options, each facility must consider not only the costs to upgrade equipment, but the potential costs to close down operations. Increased costs that result from upgrading equipment often must be passed on to the customers. However, if a large number of facilities choose to shut down rather than upgrade, the decreased capacity to treat hazardous waste could allow sufficient upward price movement to cover this increased cost. Commercial facilities that choose to shut down must immediately begin the closure process. The closure process can be very expensive. Some facilities may choose to upgrade the equipment rather than start the closure process simply on the basis of the cost of closure.

Captive incinerators

Captive incinerators face the same issues as the commercial incinerators. However, should a captive incinerator choose to shut down operations, not only will they have closure costs, but they must now pay a commercial incinerator to handle their waste--probably at a higher cost--or they have to find alternative ways to manage their wastes.


The primary effect of these revised standards on generators will be increased cost to incinerate their waste streams. With the increased cost to install new air pollution control equipment and increased amounts of hazardous waste going to commercial operators, there is little doubt that there will be upward pressure on the costs to incinerate hazardous waste. However, if costs increase too much, both captive and commercial facilities may choose to increase capacity, forcing prices back down.

Comparable fuels

Certain facilities may be able to take advantage of the comparable fuels provision of the rule. This rule allows certain wastes to be exempted from RCRA Subtitle C provisions and be burned as a fuel provided they meet certain specifications. A facility that can use the comparable fuels provision can reduce costs substantially. One facility has been able to change the way a particular waste stream is handled to remove that waste stream from RCRA. Even though this stream continues to be combusted, removing it from RCRA Subtitle C control greatly simplified regulatory obligations. Generators and captive units may want to look for innovative ways to change the characteristics of their waste streams to use the comparable fuels exemption or to take advantage of other ways to remove selected streams for RCRA regulations. The removal of comparable fuels from RCRA will probably have little impact on commercial incineration operations.


As has been the history with regulations of the hazardous waste incineration industry, the revised emissions standards will significantly change the landscape. A number of facilities will choose to stop burning rather than upgrade existing equipment to meet the revised regulations. If the capacity for burning hazardous waste sufficiently decreases, there will be upward pressure on the prices you pay. While it is unlikely that this rule will return the commercial incinerators to the high profit margins of the late 1980s, increased profit margins are possible. In addition, the changes in technology needed to meet the standards will, in some cases, be substantial. Equipment suppliers and stack testing companies will likely have a significant increase in business opportunities in the next four years.

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