ABSTRACT

Many facilities across the United States have multiple hazardous waste combustion devices. In addition, many companies have multiple hazardous waste combustion devices located at different facilities across the United States. These facilities have been, and will continue to be, required to conduct performance testing on these devices to demonstrate compliance with applicable regulations and requirements. These performance tests include Resource Conservation and Recovery Act (RCRA) Trial Burns and Risk Burns, Boiler and Industrial Furnace (BIF) Certifications of Compliance, and Clean Air Act (CAA) Maximum Achievable Control Technology (MACT) Comprehensive and Confirmatory Performance Tests. The costs and effort related to planning, conducting, and reporting these performance tests are significant to facility personnel and company economics.

This paper presents a methodology that can be used to reduce the costs and effort associated with performance testing of hazardous waste combustion devices by demonstrating that the devices are similar. For a successful demonstration, the devices must be similar, not identical. Once demonstrated to be similar, the performance test results from one combustion device are applied to one or more similar devices. The costs associated with the development of a demonstration of similarity are greater than an order of magnitude lower than the costs associated with a performance test.

The RCRA, BIF, and MACT regulations all contain provisions for allowing demonstrations of similarity. This paper will discuss each of these provisions, and will provide a framework for developing a demonstration of similarity.

INTRODUCTION

All hazardous waste combustion devices are required to conduct performance tests. These performance tests are required by the particular regulations applicable to the specific device including RCRA Trial Burns and Risk Burns, BIF Certifications of Compliance, and MACT Comprehensive and Confirmatory Performance Tests. The costs and effort associated with conducting these performance tests are significant to facility personnel and company economics. Therefore, facilities should consider applying regulatorily available methods to reduce the burden of the testing.

For companies and facilities that have multiple hazardous waste combustion devices, one method that should be explored is the requirements related to demonstrating that units are similar and using data in lieu of testing for the similar unit(s). Once demonstrated to be similar, the test results generated by one device are applied to the similar device(s). The facility’s burden is significantly reduced because planning, testing, and reporting requirements are nearly eliminated. This document discusses the regulatory requirements related to demonstrations of similarity, presents an outline for a demonstration of similarity document, presents special considerations for the similarity demonstration, and provides facility advantages for pursuing a similarity demonstration.

REGULATORY REQUIREMENTS

Hazardous waste combustion devices can be subject to RCRA, BIF, MACT, or a combination of these regulations. Each of these regulations contain requirements that allow the use of demonstrations of similarity. Each of the regulatory requirements will be briefly discussed in the following sections.

RCRA Incinerator Permits

Hazardous waste burning incinerators obtain permits pursuant to the requirements contained in Title 40 of the Code of Federal Regulations (CFR) Part 270. Specific requirements related to incinerator permits are contained in 40 CFR 270.19 (Specific Part B Information Requirements for Incinerators) and 270.62 (Hazardous Waste Incinerator Permits).

40 CFR 270.19(c) specifies the Part B permit application information required to be submitted when using data in lieu of performing a Trial Burn. Information required to be submitted includes the waste streams burned in the units (including waste analysis data), detailed engineering descriptions, comparisons of the waste streams, design comparisons, operating condition comparisons, and the expected operating limits. This section also requires the submittal of previous Trial Burn data that is used in the demonstration of similarity. If previous data is being used for demonstrating similarity, then it must be included with the application. However, if similarity is being demonstrated prior to the Trial Burn testing, the data must be provided with the Trial Burn Report.

40 CFR 270.19(d) contains the criteria the EPA uses to grant similarity for the units. These criteria include sufficient similarity of the waste streams, the similarity of the units, and the adequacy of the Trial Burn data to specify operating conditions that ensure compliance with performance standards.

40 CFR 270.62(d) specifies the Trial Burn Plan information requirements for existing incinerators. This section contains references to the 40 CFR 270.19(c) requirements when submitting information related to demonstrations of similarity.

RCRA BIF Permits

Hazardous waste burning BIFs obtain permits pursuant to the requirements contained in 40 CFR Part 270. Specific requirements related to BIF permits are contained in 40 CFR 270.22 (Specific Part B Information Requirements for Boilers and Industrial Furnaces Burning Hazardous Waste) and 270.66 (Permits for Boilers and Industrial Furnaces Burning Hazardous Waste). 40 CFR 266.102 (Permit Standards for Burners) contains references to the Trial Burn Plan requirements of 40 CFR 270.66 and the data in lieu requirements of 40 CFR 270.22. Also, Section 10.6.3 of the Technical Implementation Document for EPA’s Boiler and Industrial Furnace Regulations¹ contains the requirements for submitting data in lieu of a Trial Burn.

40 CFR 270.22(a)(6) contains the requirements for submitting data in lieu of a Trial Burn. This section requires the submittal of design and operating information required by 270.66, and that a comparison of this information be provided. Specific information required includes a description and analysis of the waste streams, and the design and operating conditions of the units being compared. This section also specifies the criteria that the EPA will use when granting similarity. These criteria include sufficient similarity of the waste streams, sufficient similarity of the devices, sufficient similarity of the operating conditions, and the adequacy of the test data to specify operating conditions that ensure compliance with performance standards. This section also requires the submittal of previous test data that is used in the demonstration of similarity. If previous data is being used for demonstrating similarity, then it must be included with the application. However, if similarity is being demonstrated prior to the Trial Burn testing, the data must be provided with the Trial Burn Report.

40 CFR 270.66(g) contains the Trial Burn Plan requirements for existing BIFs. This section contains references to the 40 CFR 270.22(a)(6) requirements when submitting information related to demonstrations of similarity.

40 CFR 266.102(d)(1) references the Trial Burn Plan requirements of 40 CFR 270.66. Also, 40 CFR 266.102(e)(2)(i), related to operating requirements for DRE demonstrations, references the data in lieu provisions of 40 CFR 270.22.

Section 10.6.3 of the Technical Implementation Document for EPA’s Boiler and Industrial Furnace Regulations¹ contains the requirements for submitting data in lieu of a Trial Burn. Information required to be submitted includes information on the hazardous waste feed streams, other feed streams, designs, and operating conditions of the units being compared. This section also states that the demonstration of similarity for a Trial Burn is the same as the requirements for waiving a Certification of Compliance with the following exceptions:

1. The similar device does not have to be located at the same site;

2. Previous data from the same unit may be used;

3. Data from dissimilar devices with inferior performance can be used;

4. Factors ancillary to environmental impacts (i.e., AWFCO system, maintenance, etc.) do not need to be similar; and

5. The data being used in lieu of the Trial Burn must meet the QA/QC requirements associated with a Trial Burn.

BIF Certifications of Compliance

Hazardous waste burning BIFs operating under interim status must perform Certification of Compliance testing pursuant to the requirements contained in 40 CFR 266.103 (Interim Status Standards for Burners). In addition, Section 5.2.5 of the Technical Implementation Document for EPA’s Boiler and Industrial Furnace Regulations¹ contains the requirements for submitting data in lieu of performing a Certification of Compliance test.

40 CFR 266.103(c)(3)(i) contains the requirements for using compliance test data from one unit in lieu of testing a similar onsite unit. The information required to be submitted includes a comparison of the hazardous waste feed streams, other feed streams, designs, operations, and maintenance of the units being compared. This section specifies the criteria for granting the similarity. These criteria require the hazardous wastes, devices, and operating conditions to be sufficiently similar, and that the data from the testing be adequate to meet the requirements of 40 CFR 266.103(c). If test data is being used for demonstrating similarity, then it must be included with the submittal. However, if similarity is being demonstrated prior to the Certification of Compliance testing, the data must be provided with the Certification of Compliance.

Section 5.2.5 of the Technical Implementation Document for EPA’s Boiler and Industrial Furnace Regulations¹ contains the requirements for submitting data in lieu of performing a Certification of Compliance test. This section requires the similarity demonstration to compare the hazardous waste feed streams, other feed streams, designs, operating conditions, and maintenance of the units being compared. The information required for the feed streams includes physical form, metals content, chlorine content, ash content, and heating value. The information required for the combustion chamber design includes the model number, basic type, burner design and/or waste firing mechanism, design temperature, volume/capacity/residence time, dimensions/shape, and refractory and/or heat removal. The air pollution control system (APCS) information required includes whether the device is shared with the similar device(s), model number, and the same components in the same order with similar design specifications. The design specifications include the basic design (i.e., spray dryer, baghouse, etc.) and the associated critical design specifications (i.e., air to cloth ratio, pressure drop, etc.).

MACT Performance Tests

The general provisions of the MACT standards are contained in 40 CFR Part 63 Subpart A. 40 CFR 63.7(h) contains the requirements for requesting a waiver of a performance test.

40 CFR 63.7(h)(3)(iii) states that information justifying the waiver of a performance test includes such items as technical, economic infeasibility, or impracticality of performing the test. It is the opinion of the authors that technical justifications for waiving a performance test include demonstrating the similarity of units, and using the data generated by one unit and applying it to the similar unit(s). Therefore, the MACT standards contain a provision to allow a technical justification (i.e., a demonstration of similarity) to request a waiver of a MACT performance test.

Beyond the justification requirements for technical, economic, or impracticality, the MACT standards do not contain any specific information requirements for inclusion in the waiver request.

RCRA Risk Burns

EPA requests the performance of Risk Burns by invoking their omnibus authority. Therefore, there are no specific regulations related to Risk Burns or the use of data in lieu of testing. However, Risk Burns are conducted in accordance with RCRA, and thus, the standards for incinerators and BIFs can be used as guidelines for requesting a demonstration of similarity for a Risk Burn. Furthermore, this approach has been successfully applied by a BIF facility that conducted a Trial Burn and Risk Burn, and received a Part B Permit based on the results of each.²

DEMONSTRATION OF SIMILARITY DOCUMENT OUTLINE

This section contains an outline for a demonstration of similarity document for submittal to the appropriate regulatory Agency. This outline also includes specific information requirements to be included in each section of the document. The outline was developed based on all the information requirements specified in the regulations for RCRA, BIF, and MACT. Therefore, the application of this outline will provide the information necessary for an Agency to grant similarity for RCRA Trial Burns and Risk Burns, BIF Certifications of Compliance, CAA MACT Comprehensive and Confirmatory Performance Tests, or any combination of these.

The outline is divided into six primary sections. An introduction section is followed by sections comparing feed streams, designs, operating conditions, and maintenance followed by a conclusions section. Each of these is further described in the following sections.

Introduction Section

The following topics should be discussed in the introduction section:

· General facility information;

· Regulatory discussion allowing demonstrations of similarity;

· Purpose of the document; and

· Brief outline of the document.

Feed Stream Comparisons

The following topics and subtopics should be discussed in the feed stream comparison section:

· Hazardous waste feed streams;

Ø Heat content;

Ø Metals content (antimony, arsenic, barium, beryllium, cadmium, chromium, lead, mercury, silver, and thallium);

Ø Total chlorine (organic and inorganic);

Ø Ash content;

Ø Viscosity or description of physical form;

Ø Identification and quantification of Appendix VIII constituents;

Ø POHC selection rationale; and

Ø Description of blending procedures (if applicable);

· Other feed streams (non-hazardous and auxiliary fuels);

Ø Heat content;

Ø Metals content (antimony, arsenic, barium, beryllium, cadmium, chromium, lead, mercury, silver, and thallium);

Ø Total chlorine (organic and inorganic);

Ø Ash content; and

Ø Viscosity or description of physical form.

Design Comparisons

The following topics and sub-topics should be discussed in the design comparisons section:

· Combustion system(s);

Ø Manufacturer’s name;

Ø Model number;

Ø Type of device (i.e., rotary kiln, water-tube boiler, etc.);

Ø Maximum design capacity;

Ø Linear dimensions including cross-sectional area; and

Ø Materials of construction;

· Feed Systems;

Ø Hazardous waste;

Ø Non-hazardous waste;

Ø Auxiliary fuel(s);

Ø Capacity of each feed system;

Ø Burner design;

Ø Atomization; and

Ø Materials of construction;

· Combustion air system;

Ø Manufacturer’s name;

Ø Model number;

Ø Type of device (i.e., centrifugal);

Ø Maximum design capacity; and

Ø Use (i.e., forced draft);

· Air pollution control system;

Ø Type of device(s);

Ø Manufacturer’s name;

Ø Model number;

Ø Maximum design capacity;

Ø Linear dimensions including cross-sectional area; and

Ø Materials of construction;

· Stack;

Ø Linear dimensions including cross-sectional area; and

Ø Materials of construction;

· Operational controls;

Ø Location and description of temperature, pressure, and flow indicating and control devices (Continuous Monitoring Systems (CMS));

Ø Air pollution control system (APCS) monitoring systems;

Ø Stack gas monitoring systems (Continuous Emission Monitoring Systems (CEMS)); and

Ø Data acquisition system;

· Automatic waste feed cut-off system;

Ø Description of operation; and

Ø Parameters interlocked.

Operating Condition Comparisons

The following topics should be discussed in the operating condition comparisons section:

· Feed stream feed rates;

· CEMS monitored parameters (i.e., CO, O₂, etc.);

· Combustion air flow rate;

· Combustion temperatures;

· APCS operating parameters;

· Stack gas velocity;

· Stack gas flow rate;

· Stack gas temperature;

· Residence time;

· DRE results;

· Air pollution control device removal efficiencies; and

· Fugitive emissions and controls.

Maintenance Comparisons

The following topics should be discussed in the maintenance comparisons section:

· Inspection parameters and frequencies;

· Maintenance parameters and frequencies;

· AWFCO test parameters and frequency; and

· Certifications and frequency (i.e., annual boiler inspections).

Conclusions Section

The following topics should be discussed in the conclusions section:

· Summarize results of the feed stream comparison;

· Summarize results of the design comparison;

· Summarize results of the operating condition comparison;

· Summarize results of the maintenance comparison; and

· Present proposed methodology for applying results from the tested unit to the similar units.

SPECIAL CONSIDERATIONS

This section discusses special items that should be considered when demonstrating the similarity of units. These special considerations are based on experience gained while developing demonstration of similarity documents and obtaining Agency approvals.

When considering the similarity of the feed streams, it is not necessary that the identical feed streams be fed to all of the units. This applies to the hazardous waste, auxiliary fuel, and other feed streams. The most important consideration is that the unit being tested should be burning the worst-case or “dirtiest” feed streams. For example, if the feed streams to two devices have similar metals and ash content, but the chlorine content to the first device is significantly higher, the first device should be tested and the results applied to the second device. Similarly, a fuel oil fired boiler would be preferentially tested versus a natural gas fired boiler. Also, a unit that is combusting vent gases would be worst-case versus another that is not fed vent gases. It may not be possible to designate a unit as combusting all of the worst-case streams. In this case, the facility may consider spiking constituents (i.e., metals, chlorine, dioxin/furan precursors, etc.) that will cause a unit to be the worst-case unit.

Many differences that are noted during the design comparison tend to be more cosmetic in nature rather than real functionality differences. For example, one unit may use a forced draft system versus an induced draft system; or a unit may have a higher design capacity than another unit; or a unit could have a horizontal combustion chamber versus a vertical combustion chamber. These differences are largely cosmetic in nature and do not affect the functionality of the units. The primary criterion that should be considered is that the units are similar, not identical.

Functionality differences relate to the overall intended operation of the unit. For example, a unit with an APCS cannot be similar to a unit that does not have an APCS, or has a differently configured APCS. Also, a unit that burns solid waste cannot be compared to one that burns only liquids. In addition, cement kilns, lightweight aggregate kilns, incinerators, and boilers cannot be compared to each other. These are all examples of functionality differences, and should not be considered for demonstrations of similarity.

One common difference between units is that they are of different sizes or capacities. For example, one boiler may be rated at 50 million Btu per hour (MM Btu/hr) and another at 60 MM Btu/hr. This sizing difference can manifest itself as differences in the volume of the combustion chambers, the maximum waste feed rates, volumetric flow rates of stack gases, etc. The main question that typically arises is whether similar units must be relatively close in size. If the functionality of the units is similar, the sizing differences should be considered a cosmetic difference between the units. Therefore, the differences in operating conditions should be closely scrutinized to ensure a proper similarity demonstration.

Operational differences between units are grouped into two categories: those that are based on size differences, and those that are not based on size differences. Operating parameters that are not generally affected by size differences include temperature, residence time, destruction and removal efficiency (DRE), carbon monoxide (CO) emissions, minimum pH of scrubbing solutions, etc. Operating parameters that are affected by size differences include waste feed rate, combustion air flow rate, steam production rate, scrubbing fluid flow rate, stack gas flow rate, etc. Therefore, when comparing two units, one would expect the temperatures, residence times, etc. to be similar and feed rates, production rates, and flow rates to differ based on the size differences.

In order to grant similarity for units with size differences, a methodology must be developed so that the results obtained from the testing of one unit can be applied to the other unit. For those operating parameters that are not affected by size differences, the test results are applied directly to the similar device. For those parameters that are affected by size differences, the ratio of the differences between the units should be factored into the test results, and then applied to the similar unit. The ratio applied should be based on actual operating results of the units and not on the design capacities. For example, two units may have a 50 percent size difference, but are operated with a 25 percent difference. In this case, the 25 percent difference should be used to factor the test results before applying them to the similar unit.

FACILITY AND AGENCY ADVANTAGES

Demonstrations of similarity are generally viewed as saving the facility significant costs and effort. This is the most obvious advantage as the cost associated with demonstrations of similarity are generally an order of magnitude lower than the costs of performing the testing. However, demonstrations of similarity can have other advantages to facilities and Agencies. The Agencies will have a reduced burden of reviewing and approving a demonstration of similarity document as opposed to a test plan, quality assurance plan, and test report. Agency, contractor, and facility personnel will spend less time in the field performing and overseeing the testing. In addition, testing time at the extremes of the unit’s operating envelope where worst-case emissions occur is significantly reduced when a demonstration of similarity is granted. Therefore, there are significant advantages associated with a demonstration of similarity.

CONCLUSIONS

The RCRA, BIF, and MACT regulations each contain provisions for allowing demonstrations of similarity to be used in lieu of performing testing on a similar unit. The regulatory requirements were reviewed and an outline was provided that can be used to develop a demonstration of similarity for Trial Burns, Risk Burns, Certifications of Compliance, and Comprehensive and Confirmatory Performance Tests. The purpose of the demonstration of similarity is to demonstrate that units are similar and not necessarily identical. Certain operating parameters are independent of size differences between units. Some operating parameters are dependent on size differences, and a methodology was presented to account for these differences. Although there are significant advantages for facilities to pursue demonstrations of similarity, Agencies and the environment can also benefit.

References

1. Technical Implementation Document for EPA’s Boiler and Industrial Furnace Regulations; United States Environmental Protection Agency; EPA530-R-92-011; March 1992.

2. Drake, G.J.; Douglas, M.L.; Jones, J.R.; Trial Burn and Risk Assessment Results for Three BIF Units; 2001 International Conference on Incineration and Thermal Treatment Technologies; Philadelphia, Pennsylvania; May 14-18, 2001.

Key Words

Demonstration of Similarity

Data in Lieu

Trial Burn

Risk Burn

Certification of Compliance

Comprehensive Performance Test

Confirmatory Performance Test

MACT

RCRA

BIF