(11) The tests to determine the enrichment factor shall be repeated if: (1) More than 3 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 occurs in any weekly sample; or (3) a quarterly test indicates that the enrichment factors have increased significantly.
• The facility shall notify the department if these tests shall be repeated.
• 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 shall reduce the feed rate of the metal in violation by 50%. If the facility has not completed the recertification process within this period, it shall stop burning or obtain an extension. Hazardous waste burning may resume only when the recertification process (ending with Step 4) has been completed.
• Meanwhile, the facility shall continue with daily kiln dust metals monitoring (Step 5) and shall 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 shall 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 s.
NR 666.103, 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 s.
NR 666.103(2)(c)), and that each facility immediately begin to operate under these limits.
These precompliance limits shall ensure that interim license emissions limits for hazardous metals, particulate matter, HCl, and Cl2 are not likely to be exceeded. Determination of the values of the precompliance limits shall be made based on either (1) conservative default assumptions provided 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.
• Determine the Tier III metal emission limit. The Tier II metal emission limit may also be used (see s.
NR 666.106).
• 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).
• 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).
• Follow appropriate procedures 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 shall be calculated from either conservative default values, or engineering judgement.
• 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.
• Engineering judgement may be used in place of conservative default assumptions if the engineering judgement is defensible and properly documented. The facility shall keep a written record of all assumptions and calculations necessary to justify the SEF. The facility shall provide this record to the department upon request and shall 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.
• Calculate the “conservative" dust metal concentration limit (DMCLc) using Equation 5.
• Submit certification of precompliance. This certification shall 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 s.
NR 666.103(2)(c), except that it is not necessary to set precompliance limits on maximum feedrate of each hazardous metal in all combined feedstreams.
• Furnaces that recycle collected PM back into the furnace (and that elect to comply with this method (see s.
NR 666.103(3)(c)2.) are subject to a special precompliance parameter, however. They shall establish precompliance limits on the maximum concentration of each hazardous metal in collected kiln dust (which shall 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.
• Metals to be monitored during precompliance testing are classified as either “critical" or “noncritical" metals.
- All metals shall 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 shall be monitored on a weekly basis, at a minimum.
- A “noncritical" metal shall 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.
• 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.
• Follow the sampling, compositing, and analytical procedures described in this method and in other appropriate methods, as they pertain to the condition and accessibility of the kiln dust.
• Samples shall be collected at least once every 8 hours, and a daily composite prepared according to appropriate 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 2 or more additional samples. These samples are referred to as the “spare" samples. These additional samples shall be collected over the same time period and according to the same procedures as those used for the “required" sample.
- Samples for “critical" metals shall be daily composites.
- Samples for “noncritical" metals shall be weekly composites, at a minimum. These samples can be composites of the original 8-hour samples, or they can be composites of daily composite samples.
• Analyze the “required" sample to determine the concentration of each metal.
- This analysis shall be completed within 48 hours of the close of the sampling period. Failure to meet this schedule is a violation.
• If the “conservative" kiln dust metal concentration limit is exceeded for any metal, refer to Step 8.
• If the “conservative" kiln dust metal concentration limit is not exceeded, continue with the daily and/or weekly monitoring (Step 5) for the duration of interim license.
(6) This step does not apply to precompliance procedures.
(7) This step does not apply to precompliance procedures.
(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 is due to a sampling or analysis error.
• If no “spare" samples were taken, refer to Step 9.
• 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.
• If the average of all the 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 10.
(9) This step does not apply to precompliance procedures.
(10) Determine if the “conservative" kiln dust metal concentration limit has been exceeded more than 3 times in the last 60 days.
• If not, log this exceedance and continue with the daily and/or weekly monitoring (Step 5).
• If so, the tests to determine the enrichment factors shall be repeated (refer to Step 11).
• This determination is made separately for each metal; for example:
- Three exceedances for each of the 10 hazardous metals are allowed within any 60-day period.
- Four exceedances of any single metal in any 60-day period is not allowed.
• This determination should be made daily, beginning on the first day of daily monitoring. For example, if 4 exceedances of any single metal occur in the first 4 days of daily monitoring, do not wait until the end of the 60-day period; refer immediately to Step 11.
(11) A revised certification of precompliance shall be submitted to the department (or certification of compliance shall be submitted) if: (1) More than 3 exceedances of the “conservative" kiln dust metal concentration limit occur within any 60 consecutive daily samples; or (2) an exceedance of the “conservative" kiln dust metal concentration limit occurs in any weekly sample.
• The facility shall notify the department if a revised certification of precompliance shall be submitted.
• The facility has up to 720 waste-burning hours to submit a certification of compliance or a revised certification of precompliance. During this period, the feed rate of the metal in violation shall be reduced by 50%. In the case of a revised certification of precompliance, engineering judgement shall be used to ensure that the “conservative" kiln dust metal concentration will not be exceeded. Examples of how this goal might be accomplished include:
- Changing equipment or operating procedures to reduce the kiln dust metal concentration;
- Changing equipment or operating procedures, or using more detailed engineering judgement, to decrease the estimated SEF and thus increase the “conservative" kiln dust metal concentration limit;
- Increasing the “conservative" kiln dust metal concentration limit by imposing a stricter PM emissions standard; or
- Increasing the “conservative" kiln dust metal concentration limit by performing a more detailed risk assessment to increase the metal emission limits.
• Meanwhile, the facility shall continue with daily kiln dust metals monitoring (Step 5).
Appendix A to Appendix IX—Statistics
A.1 Determination of Enrichment Factor
After at least 10 initial emissions tests are performed, an enrichment factor for each metal shall be determined. At the 95% confidence level, the enrichment factor, EF95% s, is based on the test results and is statistically determined so there is only a 5% chance that the enrichment factor at any given time will be larger than EF95% . Similarly, at the 99% confidence level, the enrichment factor, EF99% , is statistically determined so there is only a 1% chance that the enrichment factor at any given time will be larger than EF99% .
For a large number of samples (n > 30), EF95% is based on a normal distribution, and is equal to:
EF95% = EF + zc ó
(1)
where:
For a 95% confidence level, zc is equal to 1.645.
For a small number of samples (n<30), EF95% is based on the t-distribution and is equal to:
EF95% = EF + tc S
(4)
where the standard deviation, S, is defined as:
tc is a function of the number of samples and the confidence level that is desired. It increases in value as the sample size decreases and the confidence level increases. The 95% confidence level is used in this method to calculate the “violation" kiln dust metal concentration limit; and the 99% confidence level is sometimes used to calculate the “conservative" kiln dust metal concentration limit. Values of tc are shown in table A-1 for various degrees of freedom (degrees of freedom = sample size-1) at the 95% and 99% confidence levels. As the sample size approaches infinity, the normal distribution is approached.
A.2 Comparison of Enrichment Factor Groups
To determine if the enrichment factors measured in the quarterly tests are significantly different from the enrichment factors determined in the initial Step 2 tests, the t-test is used. In this test, the value tmeas:
