EFFECT OF SOOT BUILDUP WHILE SAMPLING WITH THE VOLATILE ORGANIC-SAMPLING TRAIN (VOST)

The U.S. Environmental Protection Agency's Method 0030(1), the Volatil e Organic Sampling Train (VOST), is used to determine the destruction and removal efficiencies of volatile organic emissions from industrial boilers co-firing hazardous waste. Previous reports detailing a hyste resis effect2,3,4 for volatile organic compounds (VOCs), resulting fro m soot build-up on the interior surfaces of boilers and industrial fur naces, raised concerns of possible VOST measurement biases due to soot deposits within the VOST. This possibility required laboratory invest igation of the method under sooty conditions. Method collection effici ency was evaluated by comparing volatile organic compound levels colle cted in a control VOST (using a soot-free particulate filter in the sa mpling probe), to VOC recoveries while using a soot-laden particulate filter in the probe. Emphasis was directed to substances in the upper range of VOC boiling points (120 to 130-degrees-C). Statistical evalua tion of the data collected indicated that recoveries for two of the hi gher boiling VOCs (chlorobenzene and octane) appeared to be negatively influenced by the presence of soot on the VOST filter. It is not like ly, however, that these findings will have a major impact on previousl y collected hazardous waste incinerator data, since the VOST-Soot effe ct was determined at moderately. high soot loadings, which are atypica l of properly operating hazardous waste incinerators.