EPA Method 324 and FAMS™ represent a significant advancement in mercury test methods. Prudent application of these methods at strategic locations along the flue gas stream provides our clients with accurate, low detection level, quality-assured data using EPA validated test methods. This data enables our clients to make informed decisions regarding mercury emissions levels and control in their boiler systems (in concert with SO2, NOx and PM emissions control), at reasonable cost. Some of the more important considerations of mercury emissions test methods are discussed below:
No emissions test program has value unless the data produced is accurate and reproducible under the same conditions. Both Method 324 and FAMS have undergone rigorous validation experiments in coal flue gas against the OHM (DOE-NETL, 2000; EERC, 2001), and the results were consistently with the statistical range of acceptance. Accordingly, Method 324 has been granted EPA 301(h) validation and FAMS™ has received EPA performance-based measurement system (PBMS) validation. In addition, both Method 324 and FAMS™ can be conducted in duplicate or triplicate simultaneously at the same sampling port, thus providing a means for determining the reproducibility of any given test measurement (typically, duplicate/triplicate test results are within 10% of each other).
QUALITY CONTROL/QUALITY ASSURANCE
Method 324 and FAMS™ traps are prepared in Frontier Geosciences' clean room with an extremely low blank level of mercury (<1 ng/trap). Although AQS exercises impeccable field QC protocol, the potential for field contamination is significantly minimized when using these sealed traps in a simple flue gas extraction train over a relatively short sampling time (typically 1 hour or less per run). OHM, conversely, requires the field preparation of both KCl and H2SO4/KMnO4 impinger solutions, extensive control of the sampling train over a 2.5 to 3 hour sampling period, and hazardous shipping of the recovered samples. Analysis of Method 324 and FAMS™ Hg aliquots is conducted on Frontier Geosciences' dedicated cold vapor atomic fluorescence spectrophotometer following the principles of the highly sensitive, fully validated Method 1631 analytical procedure. Levels of detection from CVAFS can be orders of magnitude lower than CVAAS, providing quantitative results for Hg concentrations that would be reported as non-detect by any other commonly used analytical method. Laboratory quality assurance can include field duplicates, field blanks, trip blanks, lab reagent blanks, 5-point calibration curve, continuing calibration verification, duplicate analyses, analytical spike recoveries, initial calibration blanks, continuing calibration blanks and standard reference material recovery.
Utilizing Method 324 and/or FAMS™ for mercury in flue gas studies provides an exceptional value relative to other mercury sampling methods. Both of these selected methods require a relatively short sampling time that, when coupled the capacity for introducing multiple sample trains from the same or other locations, affords our clients with a quantity of superior quality data orders of magnitude greater than other mercury testing methods conducted over similar time periods (consider that one OHM test requires upwards of 12 hours to conduct and yields only three quantitative results). Bottom line: the AQS approach produces the highest quality mercury emissions data at significantly less cost per data point. For more information, or to set up an informative meeting, contact Steve Endress.