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7.4 Nondetect Values
The US EPA is developing guidance regarding the treatment of nondetect values (data where the concentration of the constituent being measured is below the lowest concentration for which the analytical method is valid) in carrying out the statistical determinations described above. Until the guidance information is available, facilities may present their own approach to the handling of nondetect data points, but must provide supporting rationale in the operating record for consideration by the Director or permitting authority.
7.5 References
1. Shapiro, S.S. and Wilk, M.B. (1965), "An Analysis of Variance Test for Normality (complete samples)," Biometrika, 591-611.
2. Bhattacharyya, G.K. and R.A. Johnson (1977), Statistical Concepts and Methods, John Wiley and Sons, New York.
SECTION 8.0 PROCEDURES FOR DETERMINING DEFAULT VALUES FOR AIR POLLUTION CONTROL SYSTEM REMOVAL EFFICIENCIES
During interim status, owners or operators of boilers and industrial furnaces burning hazardous waste must submit documentation to Department that certifies that emissions of HCl, Cl 2, metals, and particulate matter (PM) are not likely to exceed allowable emission rates. See certification of precompliance under section 66266.103(b).103(b). This documentation also establishes interim status feed rate and operating limits for the facility. For the initial certification, estimates of emissions and system removal efficiencies (SREs) can be made to establish the operating limits. Subsequently, owners or operators must use emissions testing to demonstrate that emissions do not exceed allowable levels, and to establish operating limits. See section 66266.103(c). However, initial estimates of emissions for certification of precompliance can be based on estimated or established SREs.
The SRE combines the effect of partitioning of the chlorine, metals, or PM and the air pollution control system removal efficiency (APCS RE) for these pollutants. The SRE is defined as:
SRE = (species input-species emitted) / species input
The SRE can be calculated from the partitioning factor (PF) and APCS RE by the following formula:
SRE = 1-[(PF/100) X (1-APCS RE/100)]
where:
PF = percentage of the pollutant partitioned to the combustion gas
Estimates of the PF and/or the APCS RE can be based on either US EPA's default values or engineering judgement. US EPA's 'default values for the APCS RE for metals, HCl, Cl 2, and PM are described in this section. US EPA's default values for partitioning of these pollutants are described in section 9.0.
Guidelines for the use of engineering judgement to estimate APCS REs or PFs are described in section 9.4.
8.1 APCS RE Default Values for Metals
US EPA's default assumptions for APCS RE for metals are shown in Table 8.1-1. The default values in the table are conservative estimates of the removal efficiencies for metals in BIFs, depending on the volatility of the metal and the type of APCS.
The volatility of a metal depends on the temperature, the thermal input, the chlorine content of the waste, and the identity and concentration of the metal. Metals that do not vaporize at combustion zone temperatures are classified as "nonvolatile". Such metals typically enter the APCS in the form of large particles that are removed relatively easily. Metals that vaporize in the combustion zone and condense before entering the APCS are classified as "volatile". Such metals typically enter the APCS in the form of very fine, submicron particles that are rather inefficiently removed in many APCSs. Metals that vaporize in the combustion zone and do not condense before entering the APCS are classified as "very volatile". Such metals enter the APCS in the form of a vapor that is very inefficiently removed in many APCSs.
Typically, BIFs have combustion zone temperatures high enough to vaporize any hazardous metal at concentrations sufficient to exceed risk-based emission limits. For this reason, the default assumption is that there are no nonvolatile metals. Tables 8.1-2 and 8.1-3 are used to determine whether metals are classified as "volatile" or "very volatile" depending on the temperature entering the APCS, the thermal input, and whether the waste is chlorinated or nonchlorinated.
Table 8.1-1. -Air Pollution Control Systems (APCS) and Their Conservatively
Estomated Efficiencies for Controlling Toxic Metals (%)

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Metal Volatility
APCS Nonvolatile Volatile Very Volatile
WS 40 30 20
VS-20 80 75 20
VS-60 87 75 40
ESP-1 90 75 0
ESP-2 92 80 0
ESP-4 95 80 0
WESP 90 85 40
FF 90 80 0
SD/FF 97 90 0
DS/FF 95 90 0
WS 90 87 75

WS = Wet Scrubber including: Sieve Tray Tower, Packed Tower, Bubble Cap Tower
VS-20 = Venturi Scrubber, ca. 20-30 in W.G. Dp
VS.60 = Venturi Scrubber, ca. > 60 in W.G. Dp
ESP-1 = Electrostatic Precipitator; 1 stage
ESP-2 = Electrostatic Precipitator; 2 stage
ESP-4 = Electrostatic Precipitator; 4 stage
IWS = Ionizing Wet Scrubber
DS - Dry Scrubber
FF = Fabric Filter (Baghouse)
SD = Spray Dryer (Wet/Dry Scrubber)
WESP = Wet Electrostatic Precipitator
Table 8.1-2. -Temperature (F) Entering APCS Above Which Metals are Classified
as Very Volatile in Combustion of Nonchlorinated Wastes

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Metal Thermal Input (MMBtu/hr)
Name Symbol 1 10 100 1000 10000
Arsenic As 320 280 240 200 160
Cadmium Cd 1040 940 860 780 720
Chromium Cr 2000 1760 1580 1420 1380
Beryllium Be 1680 1440 1240 1080 980
Antimony Sb 680 600 540 480 420
Barium Ba 2240 1820 1540 1360 1240
Lead Pb 1280 1180 1080 1000 920
Mercury Hg 340 300 260 220 180
Silver Ag 1820 1640 1480 1340 1220
Thallium Tl 900 800 700 620 540

[FNFOOTNOTE:] 1 Interpolation of thermal input is not allowed. If a BIF fires between two ranges, the APCS temperature under the higher thermal input must be used.
Example: For a BIF firing 10-100 MMBtu/hr, Mercury is considered very volatile at APCS temperatures above 260 F and volatile at APCS temperatures of 260 F and below.
Table 8.1-3. -Temperature (F) Entering APCS Above Which Metals are Classified
as Very Volatile in Combustion of Chlorinated Wastes

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Metal Thermal Input (MMBtu/hr)
Name Symbol 1 10 100 1000 10000
Arsenic As 320 280 240 200 160
Cadmium Cd 1040 940 860 780 720
Chromium Cr >140 >140 >140 >140 >140
Beryllium Be 1680 1440 1240 1080 980
Antimony Sb 680 600 540 480 420
Barium Ba 2060 1840 1680 1540 1420
Lead Pb >140 >140 >140 >140 >140
Mercury Hg 340 300 260 220 180
Silver Ag 1080 940 840 740 660
Thallium Tl 900 800 700 620 540

[FNFOOTNOTE:] 1 Interpolation of thermal input is not allowed. If a BIF fires between two ranges, the APCS temperature under the higher thermal input must be used.
Example: For a BIF firing 10-100 MMBtu/hr, Mercury is considered very volatile at APCS temperatures above 260 F and volatile at APCS temperatures of 260 F and below.
A waste is considered chlorinated if chlorine is present in concentrations greater than 0.1 percent by weight. In the US EPA guidance document "Guidance for Metals and Hydrogen Chloride Controls for Hazardous Waste Incinerators, Volume IV of the Hazardous Waste Incineration Guidance Series,"(1) one percent is used for the chlorinated/nonchlorinated cutoff. However, best engineering judgement, based on examination of pilot-scale data reported by Carroll et al. (2) on the effects of waste chlorine content on metals emissions, suggests that the 1 percent cutoff may not be sufficiently conservative.
Tables 8.1-2 and 8.1-3 were compiled based on equilibrium calculations. Metals are classified as very volatile at all temperatures above the temperature at which the vapor pressure of the metal is greater than 10 percent of the vapor pressure that results in emissions exceeding the most conservative risk-based emission limits.
8.2 APCS RE Default Values for HCl and Cl 2.
Default assumptions for APCS RE for HCl in BIFs are shown in Table 8.2-1. This table is identical to the column for other BIFs except that cement kilns have a minimum HCl removal efficiency of 83 percent. Because of the alkaline nature of the raw materials in cement kilns, most of the chlorine is converted to chloride salts. Thus, the minimum APCS RE for HCl for cement kilns is independent of the APCS train.
Removal efficiency of Cl 2 for most types of APCS is generally minimal. Therefore, the default assumption for APCS RE for Cl 2 for all APCSs is 0 percent. This is applicable to all BIFs, including cement kilns.
8.3 APCS RE Default Values for Ash
Default assumptions for APCS RE for PM are also shown in Table 8.1- 4. These figures are conservative estimates of PM removal efficiencies for different types of APCSs. They are identical to the figures in the Nonvolatile APCS RE column for hazardous metals presented in Table 8.1-1 because the same collection mechanisms and collection efficiencies that apply to nonvolatile metals also apply to PM.
Table 8.2-1 -Pollution Control Systems (APCS) and Their Conservatively
Estimated Efficiencies for Removing Hydrogen Chloride (HCL) and Particulate
Matter (PM) (%)

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HCl
APCD Cement kilns Other BIFs PM
WS 97 97 40
VS-20 97 97 80
VS-60 98 98 87
ESP-1 83 0 90
ESP-2 83 0 92
ESP-4 83 0 95
WESP 83 70 90
FF 83 0 90
SD/FF 98 98 97
DS/FF 98 98 95
WS/IWS 99 99 95
IWS 99 99 90

WS = Wet Scrubber including: Sieve Tray Tower, Packed Tower, Bubble Cap Tower
PS = Proprietary Wet Scrubber Design (A number of proprietary wet scrubbers have come on the market in recent years that are highly efficient on both particulates and corrosive gases. Two such units are offered by Calvert Environmental Equipment Co. and by Hydro-Sonic Systems, Inc.).
VS-20 = Venturi Scrubber, ca. 20-30 in W.G. Dp
VS-60 = Venturi Scrubber, ca. > 60 in W.G. Dp
ESP-1 = Electrostatic Precipitator; 1 stage
ESP-2 = Electrostatic Precipitator; 2 stage
ESP-4 = Electrostatic Precipitator; 4 stage
IWS = Ionizing Wet Scrubber
DS - Dry Scrubber
FF = Fabric Filter (Baghouse)
SD = Spray Dryer (Wet/Dry Scrubber)
8.4 References
1. U.S. Environmental Protection Agency. "Guidance on Metals and Hydrogen Chloride Controls for Hazardous Waste Incinerators," Office of Solid Waste, Washington, D.C., August 1989.
2. Carroll, G.J., R.C. Thurnau, R.E. Maurnighan, L.R. Waterland, J.W. Lee, and D.J. Fournier. The Partitioning of Metals in Rotary Kiln Incineration. Proceedings of the Third International Conference on New Frontiers for Hazardous Waste Management. NTIS Document No. EPA/600/9-89/072, p. 555 (1989).
SECTION 9.0 -PROCEDURES FOR DETERMINING DEFAULT VALUES FOR PARTITIONING OF METALS, ASH, AND TOTAL CHLORIDE/CHLORINE
Pollutant partitioning factor estimates can come from two sources: default assumptions or engineering judgement. The default assumptions are discussed below for metals, HCl, Cl 2, and PM. The default assumptions are used to conservatively predict the partitioning factor for several types of BIFs. Engineering judgement-based partitioning factor estimates are discussed in section 9.4.
9.1 Partitioning Default Value for Metals
To be conservative, owners/operators may assume that 100 percent of each metal in each feed stream is partitioned to the combustion gas. Owners/operators may use this default value or a supportable, site-specific value developed following the general guidelines provided in section 9.4.
9.2 Special Procedures for Chlorine, HCl, and Cl 2
The Department has established the special procedures presented below for chlorine because the emission limits are based on the pollutants HCl and Cl 2 formed from chlorine fed to the combustor. Therefore, the owner/operator must estimate the controlled emission rate of both HCl and Cl 2 and show that they do not exceed allowable levels.
1. The default partitioning value for the fraction of chlorine in the total feed streams that is partitioned to combustion gas is 100 percent. Owners/operators may use this default value or a supportable, site-specific value developed following the general guidelines provided in section 9.4.
2. To determine the partitioning of chlorine in the combustion gas to HCl versus Cl 2, either use the default values below or use supportable site-specific values developed following the general guidelines provided in section 9.4.
w For BIFs excluding halogen acid furnaces (HAFs), with a total feed stream chlorine/hydrogen ration <=0.95, the default partitioning factor is 20 percent Cl 2, 80 percent HCl.
w For HAFs and for BIFs with a total feed stream chlorine/hydrogen ratio > 0.95, the default partitioning factor is 100 percent Cl 2.
3. To determine the uncontrolled (i.e., prior to acid gas APCS) emission rate of HCl and Cl 2, multiply the feed rate of chlorine times the partitioning factor for each pollutant. Then, for HCl, convert the chlorine emission rate to HCl by multiplying it by the ratio of the molecular weight of HCl to the molecular weight of Cl (i.e., 36.5/35.5). No conversion is needed for Cl 2.
9.3 Special Procedures for Ash
This section: (1) Explains why ash feed rate limits are not applicable to cement and light-weight aggregate kilns; (2) presents the default partitioning values for ash; and (3) explains how to convert the 0.08 gr/dscf, corrected to 7% O 2, PM emission limit to a PM emission rate.
Waiver for Cement and Light-Weight Aggregate Kilns. For cement kilns and light-weight aggregate kilns, raw material feed streams contain the vast majority of the ash input, and a significant amount of the ash in the feed stream is entrained into the kiln exhaust gas. For these devices, the ash content of the hazardous waste stream is expected to have a negligible effect on total ash emissions. For this reason, there is no ash feed rate compliance limit for cement kilns or light-weight aggregate kilns. Nonetheless, cement kilns and light-weight aggregate kilns are required to initially certify that PM emissions are not likely to exceed the PM limit, and subsequently, certify through compliance testing that the PM limit is not exceeded.
Default Partitioning Value for Ash. The default assumption for partitioning of ash depends on the feed stream firing system. There are two methods by which materials may be fired into BIFs: Suspension-firing and bed-firing.
The suspension category includes atomized and lanced pumpable liquids and suspension-fired pulverized solids. The default partitioning assumption for materials fired by these systems is that 100 percent of the ash partitions to the combustion gas.
The bed-fired category consists principally of stoker boilers and raw materials (and in some cases containerized hazardous waste) fed into cement and light-weight aggregate kilns. The default partitioning assumption for materials fired on a bed is that 5 percent of the ash partitions to the combustion gas.
Converting the PM Concentration-Based Standard to a PM Mass Emission Rate. The emission limit for BIFs is 0.08 gr/dscf, corrected to
7% O 2, unless a more stringent standard applies [e.g., a New Source Performance Standard (NSPS) or a State standard implemented under the State Implementation Plan (SIP)]. To convert the 0.08 gr/dscf standard to a PM mass emission rate:
1. Determine the flue gas O 2 concentration (percent by volume, dry) and flue gas flow rate (dry standard cubic feet per minute); and
2. Calculate the allowable PM mass emission rate by multiplying the concentration-based PM emission standard times the flue gas flow rate times a dilution correction factor equal to [(21-O 2 concentration from step 1)/(21- 7)].
9.4 Use of Engineering Judgement To Estimate Partitioning and APCS RE Values
Engineering judgement may be used in place of US EPA's conservative default assumptions to estimate partitioning and APCS RE values provided that the engineering judgement is defensible and properly documented. To properly document engineering judgement, the owner/operator must keep a written record of all assumptions and calculations necessary to justify the APCS RE used. The owner/operator must provide this record to the Director upon request and must be prepared to defend the assumptions and calculations used.
If the engineering judgement is based on emissions testing, the testing will often document the emission rate of a pollutant relative to the feed rate of that pollutant rather than the partitioning factor or APCS RE.
Examples of situations where the use of engineering judgement may be supportable to estimate a partitioning factor, APCS RE, or SRE include:
w Using emissions testing data from the facility to support an SRE, even though the testing may not meet full QA/QC procedures (e.g., triplicate test runs). The closer the test results conform with full QA/QC procedures and the closer the operating conditions during the test conform with the established operating conditions for the facility, the more supportable the engineering judgement will be.
w Applying emissions testing data documenting an SRE for one metal, including nonhazardous surrogate metals to another less volatile metal.
w Applying emissions testing data documenting an SRE from one facility to a similar facility.
w Using APCS vendor guarantees of removal efficiency.
9.5 Restrictions on Use of Test Data
The measurement of an SRE or an APCS RE may be limited by the detection limits of the measurement technique. If the emission of a pollutant is undetectable, then the calculation of SRE or APCS RE should be based on the lower limit of detectability. An SRE or APCS RE of 100 percent is not acceptable.
Further, mass balance data of facility inputs, emissions, and products/residues may not be used to support a partitioning factor, given the inherent uncertainties of such procedures. Partitioning factors other than the default values may be supported based on engineering judgement, considering, for example, process chemistry. Emissions test data may be used to support an engineering judgement-based SRE, which includes both partitioning and APCS RE.
9.5 References
1. Barton, R.G., W.D. Clark, and W.R. Seeker. (1990) "Fate of Metals in Waste Combustion Systems". Combustion Science and Technology. 74, 1-6, p. 327.
SECTION 10.0 ALTERNATIVE METHODOLOGY FOR IMPLEMENTING METALS CONTROLS
10.1 Applicability
This method for controlling metals emissions applies to cement kilns and other industrial furnaces operating under interim status that recycle emission control residue back into the furnace.
10.2 Introduction
Under this method, cement kilns and other industrial furnaces that recycle emission control residue back into the furnace must comply with a kiln dust concentration limit (i.e., a collected particulate matter (PM) limit) for each metal, as well as limits on the maximum feedrates of each of the metals in: (1) pumpable hazardous waste; and (2) all hazardous waste.
The following subsections describe how this method for controlling metals emissions is to be implemented:
w Subsection 10.3 discusses the basis of the method and the assumptions upon which it is founded;
w Subsection 10.4 provides an overview of the implementation of the method;
w Subsection 10.5 is a step-by-step procedure for implementation of the method;
w Subsection 10.6 describes the compliance procedures for this method; and
w Appendix A describes the statistical calculations and tests to be used in the method.
10.3 Basis
The viability of this method depends on three fundamental assumptions:
(1) Variations in the ratio of the metal concentration in the emitted particulate to the metal concentration in the collected kiln dust (referred to as the enrichment factor or EF) for any given metal at any given facility will fall within a normal distribution that can be experimentally determined.
(2) The metal concentrations in the collected kiln dust can be accurately and representatively measured (using procedures specified in "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods" (SW-846), incorporated by reference in section 66260.11 of chapter 11.
(3) The facility will remain in compliance with the applicable particulate matter (PM) emission standard.
Given these assumptions, metal emissions can be related to the measured concentrations in the collected kiln dust by the following equation:
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Where:
ME is the metal emitted; PME is the particulate matter emitted; DMC is the metal concentration in the collected kiln dust; and EF is the enrichment factor, which is the ratio of the metal concentration in the emitted particulate matter to the metal concentration in the collected kiln dust.
This equation can be rearranged to calculate a maximum allowable dust metal concentration limit (DMCL) by assuming worst-case conditions that: metal emissions are at the Tier III (or Tier II) limit (see section 66266.106), and that particulate emissions are at the particulate matter limit (PML):
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The enrichment factor used in the above equation must be determined experimentally from a minimum of 10 tests in which metal concentrations are measured in kiln dust and stack samples taken simultaneously. This approach provides a range of enrichment factors that can be inserted into a statistical distribution (t- distribution) to determine EF 95% and EF 99%. EF 95% is the value at which there is a 95% confidence level that the enrichment factor is below this value at any given time. Similarly,
EF 99% is the value at which there is a 99% confidence level that the enrichment factor is below this value at any given time. EF 95% is used to calculate the "violation" dust metal concentration limit (DMCL v):
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If the kiln dust metal concentration is just above this "violation" limit, and the PM emissions are at the PM emissions limit, there is a 5% chance that the metal emissions are above the Tier III limit. In such a case, the facility would be in violation of the metals standard.
To provide a margin of safety, a second, more conservative kiln dust metal concentration limit is also used. This "conservative" dust metal concentration limit (DMCL c) is calculated using a "safe" enrichment factor (SEF). If EF 99% is greater than two times the value of EF 95%, the "safe" enrichment factor can be calculated using Equation 4a:
SEF > 2 EF 95% (4a) QO2
If EF 99% is not greater than two times the value of EF 95%, the "safe" enrichment factor can be calculated using Equation 4b:
SEF > EF 99% (4b)
In cases where the enrichment factor cannot be determined because the kiln dust metal concentration is nondetectable, the "safe" enrichment factor is as follows:
SEF = 100 (4c)
For all cases, the "conservative" dust metal concentration limit is calculated using the following equation:
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If the kiln dust metal concentration at a facility is just above the "conservative" limit based on that "safe" enrichment factor provided in Equation 4a, and the PM emissions are at the PM emissions limit, there is a 5% chance that the metal emissions are above one-half the Tier III limit. If the kiln dust metal concentration at the facility is just above the "conservative" limit based on the "safe" enrichment factor provided in Equation 4b, and the PM emissions are at the PM emissions limit, there is a 1% chance that the metal emissions are above the Tier III limit. In either case, the facility would be unacceptably close to a violation. If this situation occurs more than 5% of the time, the facility would be required to rerun the series of 10 tests to determine the enrichment factor. To avoid this expense, the facility would be advised to reduce its metals feedrates or to take other appropriate measures to maintain its kiln dust metal concentrations in compliance with the "conservative" dust metal concentration limits.
In cases where the enrichment factor cannot be determined because the kiln dust metal concentration is nondetectable, and thus no EF 95% exists, the "violation" dust metal concentration limit is set at ten times the "conservative" limit:
DMCL v = 10 X DMCL c (6)
10.4 Overview
The flowchart for implementing the method is shown in Figure 10.4- 1. The general procedure is as follows:
w Follow the certification of precompliance procedures described in subsection 10.6 (to comply with section 66266.103(b)).
w For each metal of concern, perform a series of tests to establish the relationship (enrichment factor) between the concentration of emitted metal and the metal concentration in the collected kiln dust.
w Use the demonstrated enrichment factor, in combination with the Tier III (or Tier II) metal emission limit and the most stringent applicable particulate emission limit, to calculate the "violation" and "conservative" dust metal concentration limits. Include this information with the certification of compliance under section 66266.103(c).
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w Perform daily and/or weekly monitoring of the cement kiln dust metal concentration to ensure (with appropriate QA/QC) that the metal concentration does not exceed either limit.
- If the cement kiln dust metal concentration exceeds the "conservative" limit more than 5% of the time (i.e., more than three failures in last 60 tests), the series of tests to determine the enrichment factor must be repeated.
- If the cement kiln dust metal concentration exceeds the "violation" limit, a violation has occurred.
w Perform quarterly tests to verify that the enrichment factor has not increased significantly. If the enrichment factor has increased, the series of tests to determine the enrichment factor must be repeated.
10.5 Implementation Procedures
A step-by-step description for implementing the method is provided below:
(1) Prepare initial limits and test plans.
w Determine the Tier III metal emission limit. The Tier II metal emission limit may also be used (see section 66266.106).
w Determine the applicable PM emission standard. This standard is the most stringent particulate emission standard that applies to the facility. A facility may elect to restrict itself to an even more stringent self-imposed PM emission standard, particularly if the facility finds that it is easier to control particulate emissions than to reduce the kiln dust concentration of a certain metal (i.e., lead).
w Determine which metals need to be monitored (i.e., all hazardous metals for which Tier III emission limits are lower than PM emission limits-assuming PM is pure metal).
w Follow the compliance procedures described in Subsection 10.6.
w Follow the guidelines described in SW-846 for preparing test plans and waste analysis plans for the following tests:
- Compliance tests to determine limits on metal feedrates in pumpable hazardous wastes and in all hazardous wastes (as well as to determine other compliance parameters);
- Initial tests to determine enrichment factors;
- Quarterly tests to verify enrichment factors;
- Analysis of hazardous waste feedstreams; and
- Daily and/or weekly monitoring of kiln dust for continuing compliance.
(2) Conduct tests to determine the enrichment factor.
w These tests must be conducted within a 14-day period. No more than two tests may be conducted in any single day. If the tests are not completed within a 14- day period, they must be repeated.
w Simultaneous stack samples and kiln dust samples must be taken.
- Stack sampling must be conducted with the multiple metals train according to procedures provided in section 10.3 of this Methods Manual.
- Kiln dust sampling must be conducted as follows:
- Follow the sampling and analytical procedures described in SW-846 and the waste analysis plan as they pertain to the condition and accessibility of the dust.
- Samples should be representative of the last ESP or Fabric Filter in the APCS series.
w The feedrates of hazardous metals in all pumpable hazardous waste streams and in all waste streams must be monitored during these tests. It is recommended (but not required) that the feedrates of hazardous metals in all feedstreams also be monitored.
w At least ten single (noncomposited) runs are required during the tests.
- The facility must follow a normal schedule of kiln dust recharging for all of the tests.
- Three of the first five tests must be compliance tests in conformance with section 66266.103(c); i.e., they must be used to determine maximum allowable feedrates of metals in pumpable hazardous wastes, and in all hazardous wastes, as well as to determine other compliance limits (see section 66266.103(c)(1)).
- The remainder of the tests need not be conducted under full compliance test conditions; however, the facility must operate at its compliance test production rate, and it must burn hazardous waste during these tests such that the feedrate of each metal for pumpable and total hazardous wastes is at least 25% of the feedrate during compliance testing. If these criteria, and those discussed below, are not met for any parameter during a test, then either the test is not valid for determining enrichment factors under this method, or the compliance limits for that parameter must be established based on these test conditions rather than on the compliance test conditions.
w Verify that compliance emission limits are not exceeded.
- Metal emissions must not exceed Tier III (or Tier II) limits.
- PM emissions must not exceed the most stringent of applicable PM standards (or an optional self-imposed particulate standard).
w The facility must generate normal, marketable product using normal raw materials and fuels under normal operating conditions (for parameters other than those specified under this method) when these tests are conducted.
w Chromium must be treated as a special case:
- The enrichment factor for total chromium is calculated in the same way as the enrichment factor for other metals (i.e., the enrichment factor is the ratio of the concentration of total chromium in the emitted particulate matter to the concentration of total chromium in the collected kiln dust).
- The enrichment factor for hexavalent chromium (if measured) is defined as the ratio of the concentration of hexavalent chromium in the emitted particulate matter to the concentration of total chromium in the collected kiln dust.
(3) Use the enrichment factors measured in Step 2 to determine EF 95%, EF 99%, and SEF.
w Calculate EF 95% and EF 99% according to the t-distribution as described in Appendix A
w Calculate SEF by
- Equation 4a if EF 95% is determinable and if EF 99% is greater than two times EF 95%.
- Equation 4b if EF 95% is determinable and if EF 99% is not greater than two times EF 95%.
- Equation 4c if EF 95% is not determinable.
The facility may choose to set an even more conservative SEF to give itself a larger margin of safety between the point where corrective action is necessary and the point where a violation occurs.
(4) Prepare certification of compliance.
w Calculate the "conservative" dust metal concentration limit (DMCL c) using Equation 5.
- Chromium is treated as a special case. The "conservative" kiln dust chromium concentration limit is set for total chromium, not for hexavalent chromium. The limit for total chromium must be calculated using the Tier III (or Tier II) metal limit for hexavalent chromium.
- If the stack samples described in Step 2 were analyzed for hexavalent chromium, the SEF based on the hexavalent chromium enrichment factors (as defined in Step 2) must be used in this calculation.
- If the stack samples were not analyzed for hexavalent chromium, then the SEF based on the total chromium enrichment factor must be used in this calculation.
w Calculate the "violation" dust metal concentration limit (DMCL v) using Equation 3 if EF 95% is determinable, or using Equation 6 if EF 95% is not determinable.
- Chromium is treated as a special case. The "violation" kiln dust chromium concentration limit is set for total chromium, not for hexavalent chromium. The limit for total chromium must be calculated using the Tier III (or Tier II) metal limit for hexavalent chromium.
- If the stack samples taken in Step 2 were analyzed for hexavalent chromium, the EF 95% based on the hexavalent chromium enrichment factor (as defined in Step 2) should be used in this calculation.
- If the stack samples were not analyzed for hexavalent chromium, the EF 95% based on the total chromium enrichment factor must be used in this calculation.
w Submit certification of compliance.
w Steps 2-4 must be repeated for recertification, which is required once every 3 years (see section 66266.103(d)).
(5) Monitor metal concentrations in kiln dust for continuing compliance, and maintain compliance with all compliance limits for the duration of interim status.
w Metals to be monitored during compliance testing are classified as either "critical" or "noncritical" metals.
- All metals must initially be classified as "critical" metals and be monitored on a daily basis.
- A "critical" metal may be reclassified as a "noncritical" metal if its concentration in the kiln dust remains below 10% of its "conservative" kiln dust metal concentration limit for 30 consecutive daily samples. "Noncritical" metals must be monitored on a weekly basis.
- A "noncritical" metal must be reclassified as a "critical" metal if its concentration in the kiln dust is above 10% of its "conservative" kiln dust metal concentration limit for any single daily or weekly sample.
w Noncompliance with the sampling and analysis schedule prescribed by this method is a violation of the metals controls under section 66266.103.
w Follow the sampling, compositing, and analytical procedures described in this method and in SW-846 as they pertain to the condition and accessibility of the kiln dust.
w Follow the same procedures and sample at the same locations as were used for kiln dust samples collected to determine the enrichment factors (as discussed in Step 2).
w Samples must be collected at least once every 8 hours, and a daily composite must be prepared according to SW-846 procedures.
- At least one composite sample is required. This sample is referred to as the "required" sample.
- For QA/QC purposes, a facility may elect to collect two or more additional samples. These samples are referred to as the "spare" samples. These additional samples must be collected over the same time period and according to the same procedures as those used for the "required" sample.
- Samples for "critical" metals must be daily composites.
- Samples for "noncritical" metals must be weekly composites. These samples can be composites of the original 8-hour samples, or they can be composites of daily composite samples.
w Analyze the "required" sample to determine the concentration of each metal.
- This analysis must be completed within 48 hours of the close of the sampling period. Failure to meet this schedule is a violation of the metals standards of section 66266.103.
w If the "conservative" kiln dust metal concentration limit is exceeded for any metal, refer to Step 8.
w If the "conservative" kiln dust metal concentration limit is not exceeded, continue with the daily or weekly monitoring (Step 5) for the duration of interim status.
w Conduct quarterly enrichment factor verification tests, as described in Step 6.
(6) Conduct quarterly enrichment factor verification tests.
w After certification of compliance with the metals standards, a facility must conduct quarterly enrichment factor verification tests every three months for the duration of interim status. The first quarterly test must be completed within three months of certification (or recertification). Each subsequent quarterly test must be completed within three months of the preceding quarterly test. Failure to meet this schedule is a violation.
w Simultaneous stack samples and kiln dust samples must be collected.
w Follow the same procedures and sample at the same locations as were used for kiln dust samples and stack samples collected to determine the enrichment factors (as discussed in Step 2).
w At least three single (noncomposite) runs are required. These tests need not be conducted under the operating conditions of the initial compliance test; however, the facility must operate under the following conditions:
- It must operate at compliance test production rate.
- It must burn hazardous waste during the test, and for the 2-day period immediately preceding the test, such that the feedrate of each metal for pumpable and total hazardous wastes consist of at least 25% of the operating limits established during the compliance test.
- It must remain in compliance with all compliance parameters (see section 66266.103(c)(1).
- It must follow a normal schedule of kiln dust recharging.
- It must generate normal marketable product from normal raw materials during the tests.
(7) Conduct a statistical test to determine if the enrichment factors measured in the quarterly verification tests have increased significantly from the enrichment factors determined in the tests conducted in Step 2. The enrichment factors have increased significantly if all three of the following criteria are met:
w By applying the t-test described in appendix A, it is determined that the enrichment factors measured in the quarterly tests are not taken from the same population as the enrichment factors measured in the Step 2 tests;
w The EF 95% calculated for the combined data sets (i.e., the quarterly test data and the original Step 2 test data) according to the t-distribution (described in appendix A) is more than 10% higher than the EF 95% based on the enrichment factors previously measured in Step 2; and
w The highest measured kiln dust metal concentration recorded in the previous quarter is more than 10% of the "violation" kiln dust concentration limit that would be calculated from the combined EF 95%.
If the enrichment factors have increased significantly, the tests to determine the enrichment factors must be repeated (refer to Step 11). If the enrichment factors have not increased significantly, continue to use the kiln dust metal concentration limits based on the enrichment factors previously measured in Step 2, and continue with the daily and/or weekly monitoring described in Step 5.
(8) If the "conservative" kiln dust metal concentration limit was exceeded for any metal in any single analysis of the "required" kiln dust sample, the "spare" samples corresponding to the same period may be analyzed to determine if the exceedance was due to a sampling or analysis error.
w If no "spare" samples were taken, refer to Step 9.
w If the average of all the samples for a given day (or week, as applicable) (including the "required" sample and the "spare" samples) does not exceed the "conservative" kiln dust metal concentration limit, no corrective measures are necessary; continue with the daily and/or weekly monitoring as described in Step 5.
w If the average of all samples for a given day (or week, as applicable) exceeds the "conservative" kiln dust metal concentration limit, but the average of the "spare" samples is below the "conservative" kiln dust metal concentration limit, apply the Q-test, described in appendix A, to determine whether the "required" sample concentration can be judged as an outlier.
- If the "required" sample concentration is judged an outlier, no corrective measures are necessary; continue with the daily and/or weekly monitoring described in Step 5.
- If the "required" sample concentration is not judged an outlier, refer to Step 9.
(9) Determine if the "violation" kiln dust metal concentration has been exceeded based on either the average of all the samples collected during the 24-hour period in question, or if discarding an outlier can be statistically justified by the Q-test described in appendix A, on the average of the remaining samples.
w If the "violation" kiln dust metal concentration limit has been exceeded, a violation of the metals controls under section 66266.103(c) has occurred. Notify the Director that a violation has occurred. Hazardous waste may be burned for testing purposes for up to 720 operating hours to support a revised certification of compliance. Note that the Director may grant an extension of the hours of hazardous waste burning under section 66266.103(c)(7) if additional burning time is needed to support a revised certification for reasons beyond the control of the owner or operator. Until a revised certification of compliance is submitted to the Director, the feedrate of the metals in violation in total and pumpable hazardous waste feeds is limited to 50% of the previous compliance test limits.
w If the "violation" kiln dust metal concentration has not been exceeded:
- If the exceedance occurred in a daily composite sample, refer to Step 10.
- If the exceedance occurred in a weekly composite sample, refer to Step 11.
(10) Determine if the "conservative" kiln dust metal concentration limit has been exceeded more than three times in the last 60 days.
w If not, log this exceedance and continue with the daily and/or weekly monitoring (Step 5).
w If so, the tests to determine the enrichment factors must be repeated (refer to Step 11).
w This determination is made separately for each metal; For example,
- Three exceedances for each of the ten hazardous metals are allowed within any 60-day period.
- Four exceedances of any single metal in any 60-day period is not allowed.
w This determination should be made daily, beginning on the first day of daily monitoring. For example, if four exceedances of any single metal occur in the first four days of daily monitoring, do not wait until the end of the 60-day period; refer immediately to Step 11.
(11) The tests to determine the enrichment factor must be repeated if: (1) More than three exceedances of the "conservative" kiln dust metal concentration limit occur within any 60 consecutive daily samples; (2) an excursion of the "conservative" kiln dust metal concentration limit oc-
curs in any weekly sample; or (3) a quarterly test indicates that the enrichment factors have increased significantly.
w The facility must notify the Director if these tests must be repeated.
w The facility has up to 720 hazardous-waste burning hours to redetermine the enrichment factors for the metal or metals in question and to recertify (beginning with a return to Step 2). During this period, the facility must reduce the feed rate of the metal in violation by 50%. If the facility has not completed the recertification process within this period, it must stop burning or obtain an extension. Hazardous waste burning may resume only when the recertification process (ending with Step 4) has been completed.
w Meanwhile, the facility must continue with daily kiln dust metals monitoring (Step 5) and must remain in compliance with the "violation" kiln dust metal concentration limits (Step 9).
10.6 Precompliance Procedures
Cement kilns and other industrial furnaces that recycle emission control residue back into the furnace must comply with the same certification schedules and procedures (with the few exceptions described below) that apply to other boilers and industrial furnaces. These schedules and procedures, as set forth in section 66266.103, require no later than the effective date of the rule, each facility submit a certification which establishes precompliance limits for a number of compliance parameters (see section 66266.103(b)(3)), and that each facility immediately begin to operate under these limits.
These precompliance limits must ensure that interim status emissions limits for hazardous metals, particulate matter, HCl, and Cl 2 are not likely to be exceeded. Determination of the values of precompliance limits must be made based on either (1) conservative default assumptions in this Methods Manual, or (2) engineering judgement.
The flowchart for implementing the precompliance procedures is shown in Figure 10.6-1. The step-by-step precompliance implementation procedure is described below. The precompliance implementation procedures and numbering scheme are similar to those used for the compliance procedures described in Subsection 10.5.
(1) Prepare initial limits and test plans.
w Determine the Tier III metal emission limit. The Tier II metal emission limit may also be used (see section 66266.106).
w Determine the applicable PM emission standard. This standard is the most stringent particulate emission standard that applies to the facility. A facility may elect to restrict itself to an even more stringent self-imposed PM emission standard, particularly if the facility finds that it is easier to control particulate emissions than to reduce the kiln dust concentration of a certain metal (i.e., lead).
w Determine which metals need to be monitored (i.e., all hazardous metals for which Tier III emission limits are lower than PM emission limits, assuming PM is pure metal).
w Follow the procedures described in SW-846 for preparing waste analysis plans for the following tasks:
- Analysis of hazardous waste feedstreams.
- Daily and/or weekly monitoring of kiln dust concentrations for continuing compliance.
(2) Determine the "safe" enrichment factor for precompliance. In this context, the "safe" enrichment factor is a conservatively high estimate of the enrichment factor (the ratio of the emitted metal concentration to the metal concentration in the collected kiln dust). The "safe" enrichment factor must be calculated from either conservative default values, or engineering judgement.
TABULAR OR GRAPHIC MATERIAL SET AT THIS POINT IS NOT DISPLAYABLE
w Conservative default values for the "safe" enrichment factor are as follows:
- SEF = 10 for all hazardous metals except mercury. SEF = 10 for antimony, arsenic, barium, beryllium, cadmium, chromium, lead, silver, and thallium.
- SEF = 100 for mercury.
w Engineering judgement may be used in place of conservative default assumptions provided that the engineering judgement is defensible and properly documented. The facility must keep a written record of all assumptions and calculations necessary to justify the SEF. The facility must provide this record to Department upon request and must be prepared to defend these assumptions and calculations.
Examples of situations where the use of engineering judgement is appropriate include:
- Use of data from precompliance tests;
- Use of data from previous compliance tests; and
- Use of data from similar facilities.
(3) This step does not apply to precompliance procedures.
(4) Prepare certification of precompliance.
w Calculate the "conservative" dust metal concentration limit (DMCL c) using Equation 5.
w Submit certification of precompliance. This certification must include precompliance limits for all compliance parameters that apply to other boilers and industrial furnaces (i.e., those that do not recycle emission control residue back into the furnace) as listed in section 66266.103(b)(3), except that it is not necessary to set precompliance limits on maximum feedrate of each hazardous metal in all combined feedstreams.
w Furnaces that recycle collected PM back into the furnace (and that elect to comply with this method (see section 66266.103(c)(3)(ii)) are subject to a special precompliance parameter, however. They must establish precompliance limits on the maximum concentration of each hazardous metal in collected kiln dust. (which must be set according to the procedures described above).
(5) Monitor metal concentration in kiln dust for continuing compliance, and maintain compliance with all precompliance limits until certification of compliance has been submitted.
w Metals to be monitored during precompliance testing are classified as either "critical" or "noncritical" metals.
- All metals must initially be classified as "critical" metals and be monitored on a daily basis.
- A "critical" metal may be reclassified as a "noncritical" metal if its concentration in the kiln dust remains below 10% of its "conservative" kiln dust metal concentration limit for 30 consecutive daily samples. "Noncritical" metals must be monitored on a weekly basis, at a minimum.
- A "noncritical" metal must be reclassified as a "critical" metal if its concentration in the kiln dust is above 10% of its "conservative" kiln dust metal concentration limit for any single daily or weekly sample.
w It is a violation if the facility fails to analyze the kiln dust for any "critical" metal on any single day or for any "noncritical" metal during any single week, when hazardous waste is burned.
w Follow the sampling, compositing, and analytical procedures described in this method and in SW-846 as they pertain to the condition and accessibility of the kiln dust. (continued)