2 Test Methods
2.1 Stack test methods
2.1.1 PCDD and PCDF
PCDD and PCDF were sampled and analysed as per US EPA Method 23, Determination of Polychlorinated Dibenzo-p-dioxins and Polychlorinated Dibenzofurans from Stationary Sources. Figure 1 is a diagram of the sample train used for Method 23.
The sample media used was soxhlet, which was extracted in the lab for up to 16 hours to remove possible contamination prior to sampling. An internal standard spike was added to the resin. This spike was used to calculate the recovery efficiencies and can also be used as an indicator of lost sample.
At the sites, samples were withdrawn from the gas stream and drawn through the sample probe on a glass fibre filter where the particulate matter was collected. The gaseous fraction passes through a packed column of absorbent material (XAD-2 resin) where all aromatic compounds are absorbed. The sample could not be separated into a particle vapour fraction as this separation is defined by the operation of the sampling train.
After sampling the train was removed to a clean location and rinsed with acetone, methylene chloride and toluene. These washings were added to the sample for analysis.
The PCDD and PCDF were extracted from the sample, separated by high-resolution gas chromatography, and measured by high-resolution mass spectrometry.
2.1.2 Combustion gases
Figure 2 is a diagram of the combustion gas analyser used. K2 Environmental Ltd's combustion gas analyser meets the requirements of the US EPA and can measure the following gases.
- Carbon Monoxide - US EPA CTM 034 Test Method - Determination of Oxygen, Carbon Monoxide and Oxides of Nitrogen from Stationary Sources for Periodic Monitoring (Portable Electrochemical Analyzer Procedure).
- Carbon Dioxide - US EPA Method 3A CO2 and O2 Determination of Oxygen and Carbon Dioxide Concentrations in Emissions from Stationary Sources (Instrumental Analyzer Procedure, UV, NDIR, or fluorescence).
- Oxides of Nitrogen (NO, NO2 and NOX) - Method 7E NOX Determination of Nitrogen Oxides Emissions from Stationary Sources (Instrumental Analyzer Procedure). CTM 022 NOX Determination of Nitric Oxide, Nitrogen Dioxide and NO Emissions from Stationary Combustion Sources by Electrochemical Analyser.
- Sulphur dioxide - US EPA Method 6C Determination of Sulphur Dioxide Emissions from Stationary Sources (Instrumental Analyzer Procedure), and Approved Alternative Method ALT004 Alternative Analytical Technology for Instrumental Methods 3A and 6C.
- Oxygen - US EPA Method 3A CO2 and O2 Determination of Oxygen and Carbon Dioxide Concentrations in Emissions from Stationary Sources (Instrumental Analyzer Procedure, UV, NDIR, or fluorescence).
- Combustible gases - Combustion gases are determined using a catalytic sensor, range 0-6.00% with resolution 0.01%. The accuracy is 10% of the reading in CH4.
Gas samples were drawn from the stack filtered and the moisture removed by a permeation drying system. The gas then passed to the analyser where a portion of the gas was analysed. The analyser used Infrared to measure the concentration of carbon dioxide. All other measurements were made with advanced chemical cells. All gasses were logged and reported.
The analyser was calibrated before and after sampling. However, it was calibrated using span gas and zero gas only. Due to supply difficulties the stack emission testers were not able to calibrate the analyser with a mid range gas. This is a minor deviation from the standard.
2.2 Ambient sampling
2.2.1 PCDD and PCDF
PCDD and PCDF were analysed as per US EPA Method TO-9A. Determination of Polychlorinated, Polybrominated and Brominated/Chlorinated Dibenzo-p-dioxins and Dibenzofurans in Ambient Air. Figure 3 is a diagram of the high-volume sampler arrangement.
The sample media used was soxhlet extracted in the lab for up to 16 hours to remove possible contamination prior to sampling. An internal standard spike was added to the resin. This spike was used to calculate the recovery efficiencies and also used as an indicator of lost sample.
At the site, samples were withdrawn from the ambient air and drawn through the dual chamber sampling module. Particulate matter was collected on a glass fibre filter; the gaseous fraction passed through a packed column of absorbent material (XAD-2 resin) where all aromatic compounds are absorbed.
After sampling the filter and trap were removed for analysis. PCDD and PCDF were extracted from the sample, separated by high-resolution gas chromatography, and measured by high-resolution mass spectrometry.
