2.2.3.1 CEMS Installation and Measurement Locations. The CEMS shall be installed in a location in which measurements representative of the source's emissions can be obtained. The optimum location of the sample interface for the CEMS is determined by a number of factors, including ease of access for calibration and maintenance, the degree to which sample conditioning will be required, the degree to which it represents total emissions, and the degree to which it represents the combustion situation in the firebox. The location should be as free from in-leakage influences as possible and reasonably free from severe flow disturbances. The sample location should be at least 2 equivalent duct diameters downstream from the nearest control device, point of pollutant generation, or other point at which a change in the pollutant concentration or emission rate occurs and at least 0.5 diameter upstream from the exhaust or control device. The equivalent duct diameter is calculated as per
40 CFR part 60, Appendix A, method 1, section 2.1, incorporated by reference in s.
NR 660.11. If these criteria are not achievable or if the location is otherwise less than optimum, the possibility of stratification should be investigated as described in section 2.2.3.2. The measurement point shall be within the centroidal area of the stack or duct cross section.
2.2.3.2 Stratification Test Procedure. Stratification is defined as a difference in excess of 10% between the average concentration in the duct or stack and the concentration at any point more than 1.0 meter from the duct or stack wall. To determine whether effluent stratification exists, a dual probe system should be used to determine the average effluent concentration while measurements at each traverse point are being made. One probe, located at the stack or duct centroid, is used as a stationary reference point to indicate the change in effluent concentration over time. The second probe is used for sampling at the traverse points specified in
40 CFR part 60 Appendix A, method 1, incorporated by reference in s.
NR 660.11. The monitoring system samples sequentially at the reference and traverse points throughout the testing period for 5 minutes at each point.
2.2.4 CEMS Performance and Equipment Specifications
If this method is applied in highly explosive areas, caution and care shall be exercised in choice of equipment and installation.
2.2.4.1 Flame Ionization Detector (FID) Analyzer. A heated FID analyzer capable of meeting or exceeding these specifications. Heated systems shall maintain the temperature of the sample gas between 150 °C (300 °F) and 175 °C (350 °F) throughout the system. This requires all system components such as the probe, calibration valve, filter, sample lines, pump, and the FID to be kept heated at all times such that no moisture is condensed out of the system.
Note: As specified in the regulations, unheated HC CEMs may be considered an acceptable interim alternative monitoring technique. For additional notes, see section 2.2.10. The essential components of the measurement system are described below:
2.2.4.1.1 Sample Probe. Stainless steel, or equivalent, to collect a gas sample from the centroidal area of the stack cross-section.
2.2.4.1.2 Sample Line. Stainless steel or Teflon tubing to transport the sample to the analyzer.
Note: Mention of trade names or specific products does not constitute endorsement by the department.
2.2.4.1.3 Calibration Valve Assembly. A heated 3-way valve assembly to direct the zero and calibration gases to the analyzer is recommended. Other methods, such as quick-connect lines, to route calibration gas to the analyzers are applicable.
2.2.4.1.4 Particulate Filter. An in-stack or out-of-stack sintered stainless steel filter is recommended if exhaust gas particulate loading is significant. An out-of-stack filter shall be heated.
2.2.4.1.5 Fuel. The fuel specified by the manufacturer (e.g., 40% hydrogen/60% helium, 40% hydrogen/60% nitrogen gas mixtures, or pure hydrogen) should be used.
2.2.4.1.6 Zero Gas. High purity air with less than 0.1 parts per million by volume (ppm) HC as methane or carbon equivalent or less than 0.1% of the span value, whichever is greater.
2.2.4.1.7 Calibration Gases. Appropriate concentrations of propane gas (in air or nitrogen). Preparation of the calibration gases should be done according to the procedures in EPA Protocol 1, incorporated by reference in s.
NR 660.11. In addition, the manufacturer of the cylinder gas should provide a recommended shelf life for each calibration gas cylinder over which the concentration does not change by more than
±2% from the certified value.
2.2.4.2 CEMS Span Value. 100 ppm propane.
2.2.4.3 Daily Calibration Gas Values. The owner or operator shall choose calibration gas concentrations that include zero and high-level calibration values.
2.2.4.3.1 The zero level may be between 0 and 20 ppm (0 and 20% of the span value).
2.2.4.3.2 The high-level concentration shall be between 50 and 90 ppm (50 and 90% of the span value).
2.2.4.4 Data Recorder Scale. The strip chart recorder, computer, or digital recorder shall be capable of recording all readings within the CEMS's measurement range and shall have a resolution of 0.5 ppm (0.5% of span value).
2.2.4.5 Response Time. The response time for the CEMS may not exceed 2 minutes to achieve 95% of the final stable value.
2.2.4.6 Calibration Drift. The CEMS shall allow the determination of CD at the zero and high-level values. The CEMS calibration response may not differ by more than ±3 ppm (±3% of the span value) after each 24-hour period of the 7-day test at both zero and high levels.
2.2.4.7 Calibration Error. The mean difference between the CEMS and reference values at all 3 test points listed below shall be no greater than 5 ppm (±5% of the span value).
2.2.4.7.1 Zero Level. Zero to 20 ppm (0 to 20% of span value).
2.2.4.7.2 Mid-Level. 30 to 40 ppm (30 to 40% of span value).
2.2.4.7.3 High-Level. 70 to 80 ppm (70 to 80% of span value).
2.2.4.8 Measurement and Recording Frequency. The sample to be analyzed shall pass through the measurement section of the analyzer without interruption. The detector shall measure the sample concentration at least once every 15 seconds. An average emission rate shall be computed and recorded at least once every 60 seconds.
2.2.4.9 Hourly Rolling Average Calculation. The CEMS shall calculate every minute an hourly rolling average, which is the arithmetic mean of the 60 most recent one-minute average values.
2.2.4.10 Retest. If the CEMS produces results within the specified criteria, the test is successful. If the CEMS does not meet one or more of the criteria, necessary corrections shall be made and the performance tests repeated.
2.2.5 Performance Specification Test (PST) Periods
2.2.5.1 Pretest Preparation Period. Install the CEMS, prepare the PTM test site according to the specifications in section 2.2.3, and prepare the CEMS for operation and calibration according to the manufacturer's written instructions. A pretest conditioning period similar to that of the 7-day CD test is recommended to verify the operational status of the CEMS.
2.2.5.2 Calibration Drift Test Period. While the facility is operating under normal conditions, determine the magnitude of the CD at 24-hour intervals for 7 consecutive days according to the procedure given in section 2.2.6.1. All CD determinations shall be made following a 24-hour period during which no unscheduled maintenance, repair, or adjustment takes place. If the combustion unit is taken out of service during the test period, record the onset and duration of the downtime and continue the CD test when the unit resumes operation.
2.2.5.3 Calibration Error Test and Response Time Test Periods. Conduct the CE and response time tests during the CD test period.
2.2.6 Performance Specification Test Procedures
2.2.6.1 Calibration Drift Test.
2.2.6.1.1 Sampling Strategy. Conduct the CD test at 24-hour intervals for 7 consecutive days using calibration gases at the 2 daily concentration levels specified in section 2.2.4.3. Introduce the 2 calibration gases into the sampling system as close to the sampling probe outlet as practical. The gas shall pass through all CEM components used during normal sampling. If periodic automatic or manual adjustments are made to the CEMS zero and calibration settings, conduct the CD test immediately before these adjustments, or conduct it in such a way that the CD can be determined. Record the CEMS response and subtract this value from the reference (calibration gas) value. To meet the specification, none of the differences shall exceed 3 ppm.
2.2.6.1.2 Calculations. Summarize the results on a data sheet. An example is shown in Figure 2.2-1. Calculate the differences between the CEMS responses and the reference values.
2.2.6.2 Response Time. The entire system including sample extraction and transport, sample conditioning, gas analyses, and the data recording is checked with this procedure.
2.2.6.2.1 Introduce the calibration gases at the probe as near to the sample location as possible. Introduce the zero gas into the system. When the system output has stabilized (no change greater than 1 percent of full scale for 30 sec), switch to monitor stack effluent and wait for a stable value. Record the time (upscale response time) required to reach 95% of the final stable value.
2.2.6.2.2 Next, introduce a high-level calibration gas and repeat the above procedure. Repeat the entire procedure 3 times and determine the mean upscale and downscale response times. The longer of the 2 means is the system response time.
2.2.6.3 Calibration Error Test Procedure.
2.2.6.3.1 Sampling Strategy. Challenge the CEMS with zero gas and EPA Protocol 1 cylinder gases at measurement points within the ranges specified in section 2.2.4.7.
2.2.6.3.1.1 The daily calibration gases, if EPA Protocol 1, incorporated by reference in s.
NR 660.11, may be used for this test.
2.2.9 Quality Assurance (QA)
Proper calibration, maintenance, and operation of the CEMS is the responsibility of the owner or operator. The owner or operator shall establish a QA program to evaluate and monitor CEMS performance. As a minimum, the QA program shall include:
2.2.9.1 A daily calibration check for each monitor. The calibration shall be adjusted if the check indicates the instrument's CD exceeds 3 ppm. The gases shall be injected as close to the probe as possible to provide a check of the entire sampling system. If an alternative calibration procedure is desired (e.g., direct injections or gas cells), subject to department approval, the adequacy of this alternative procedure may be demonstrated during the initial 7-day CD test. Periodic comparisons of the 2 procedures are suggested.
2.2.9.2 A daily system audit. The audit shall include a review of the calibration check data, an inspection of the recording system, an inspection of the control panel warning lights, and an inspection of the sample transport and interface system (e.g., flowmeters, filters), as appropriate.
2.2.9.3 A quarterly CE test. Quarterly RA tests may be substituted for the CE test when approved by the department on a case-by-case basis.
2.2.9.4 An annual performance specification test.
2.2.10 Alternative Measurement Technique
The regulations allow gas conditioning systems to be used In conjunction with unheated HC CEMs during an interim period. This gas conditioning may include cooling to not less than 40° F and the use of condensate traps to reduce the moisture content of sample gas entering the FID to less than 2%. The gas conditioning system, however, may not allow the sample gas to bubble through the condensate as this would remove water soluble organic compounds. All components upstream of the conditioning system should be heated as described in section 2.2.4 to minimize operating and maintenance problems.
2.2.11 References
1. Measurement of Volatile Organic Compounds-Guideline Series. U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, EPA-450/2-78-041, June 1978.
2. Traceability Protocol for Establishing True Concentrations of Gases Used for Calibration and Audits of Continuous Source Emission Monitors (Protocol No. 1). U.S. Environmental Protection Agency ORD/EMSL, Research Triangle Park, North Carolina, 27711, June 1978.
3. Gasoline Vapor Emission Laboratory Evaluation-Part 2. U.S. Environmental Protection Agency, OAQPS, Research Triangle Park, North Carolina, 27711, EMB Report No. 76-GAS-6, August 1975.
Section 3.0
Sampling And Analytical Methods
Note: The sampling and analytical methods to the BIF manual are published in “Test Methods for Evaluating Solid Waste, Physical/Chemical Methods", EPA SW-846, as incorporated by reference in s.
NR 660.11.
Section 4.0 Procedure For Estimating The
Toxicity Equivalence Of Chlorinated
Dibenzo-p-dioxin And Dibenzofuran Congeners
PCDDs and PCDFs shall be determined using whichever is the most recent version between SW–846 Method 0023A (incorporated by reference in s.
NR 660.11) as identified, or QAQPS Method 23 in appendix A of
40 CFR part 60. In this method individual congeners or homologues
1 are measured and then summed to yield a total PCDD/PCDF value. No toxicity factors are specified in the method to compute risks from such emissions.
Note: 1 The term “congener" refers to any one particular member of the same chemical family; e.g., there are 75 congeners of chlorinated dibenzo-p-dioxins. The term “homologue" refers to a group of structurally related chemicals that have the same degree of chlorination. For example, there are eight homologues of CDs, monochlorinated through octachlorinated. Dibenzo-p-dioxins and dibenzofurans that are chlorinated at the 2,3,7, and 8 positions are denoted as “2378" congeners, except when 2,3,7,8-TCDD is uniquely referred to: e.g., 1,2,3,7,8-PeCDF and 2,3,4,7,8-PeCDF are both referred to as “2378-PeCDFs."
For the purpose of estimating risks posed by emissions from boilers and industrial furnaces, however, specific congeners and homologues shall be measured using the specified method and then multiplied by the assigned toxicity equivalence factors (TEFs), using procedures described in “Interim Procedures for Estimating Risks Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans (CDDs and CDFs) and 1989 Update", EPA/625/3-89/016, March 1989, incorporated by reference in s.
NR 660.11. The resulting 2,3,7,8-TCDD equivalents value is used in the subsequent risk calculations and modeling efforts as discussed in the BIF final rule.
The procedure for calculating the 2,3,7,8-TCDD equivalent is as follows:
1. Using method 23, determine the concentrations of 2,7,3,8-congeners of various PCDDs and PCDFs in the sample.
2. Multiply the congener concentrations in the sample by the TEF listed in Table 4.0-1 to express the congener concentrations in terms of 2,3,7,8-TCDD equivalent. Note that congeners not chlorinated at 2,3,7, and 8 positions have a zero toxicity factor in this table.
3. Add the products obtained in step 2, to obtain the total 2,3,7,8-TCDD equivalent in the sample.
Sample calculations are provided in EPA document No. EPA/625/3-89/016, March 1989, incorporated by reference in s.
NR 660.11. -
See PDF for table 
Reference: Adapted from NATO/CCMS, 1988a.
1Interim Procedures for Estimating Risks Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and Dibenzofurans (CDDs and CDFs) 1989 Update EPA/625/3-89/016, March 1989, incorporated by reference in s.
NR 660.11.
Section 5.0 Hazardous Waste Combustion Air Quality Screening Procedure
The HWCAQSP is a combined calculation/reference table approach for conservatively estimating short-term and annual average facility impacts for stack emissions. The procedure is based on extensive short-term modeling of 11 generic source types and on a set of adjustment factors for estimating annual average concentrations from short-term concentrations. Facility impacts may be determined based on the selected worst-case stack or on multiple stacks, in which the impacts from each stack are estimated separately and then added to produce the total facility impact.
This procedure is most useful for facilities with multiple stacks, large source-to-property boundary distances, and complex terrain between one and 5 km from the facility. To ensure a sufficient degree of conservatism, the HWCAQSP may not be used if any of the 5 screening procedure limitations listed below are true:
• The facility is located in a narrow valley less than 1 km wide;
• The facility has a stack taller than 20 m and is located such that the terrain rises to the stack height within 1 km of the facility;
• The facility has a stack taller than 20 m and is located within 5 km of the shoreline of a large body of water;
• The facility property line is within 200 m of the stack and the physical stack height is less than 10 m; or
• On-site receptors are of concern, and stack height is less than 10 m.
If any of these criteria are met or the department determines that this procedure is not appropriate, then detailed site-specific modeling or modeling using the “Screening Procedures for Estimating the Air Quality Impact of Stationary Sources," EPA -450/4-88-010, Office of Air Quality Planning and Standards, August 1988, incorporated by reference in s.
NR 660.11, is required. Detailed site-specific dispersion modeling shall conform to the EPA “Guidance on Air Quality Models (Revised)", EPA 450/2-78-027R, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina, July 1986, incorporated by reference in s.
NR 660.11. This document provides guidance on both the proper selection and regulatory application of air quality models.
Introduction
The Hazardous Waste Combustion Air Quality Screening Procedure (HWCAQSP) (also referred to hereafter as “the screening procedure" or “the procedure") provides a quick, easy method for estimating maximum (hourly) and annual average ambient air impacts associated with the combustion of hazardous waste. The methodology is conservative in nature and estimates dispersion coefficients2 based on facility-specific information.
Note: 2 The term dispersion coefficient refers to the change in ambient air concentration (mg/m 3) resulting from a source with an emission rate of 1 g/sec.
The screening procedure can be used to determine emissions limits at sites where the nearest meteorological (STAR) station is not representative of the meteorology at the site. If the screen shows that emissions from the site are adequately protective, then the need to collect site-specific meteorological data can be eliminated.
The screening procedure is generally most helpful for facilities meeting one or more of the following conditions:
• Multiple stacks with substantially different release specifications (e.g., stack heights differ by >50%, exit temperatures differ by >50 °K, or the exit flow rates differ by more than a factor of 2),
• Terrain located between 1 km and 5 km from the site increases in elevation by more than the physical height of the shortest stack (i.e., the facility is located in complex terrain), or
• Significant distance between the facility's stacks and the site boundary [guidance on determining whether a distance is “significant" is provided in Step 6(B) of the procedure].
