Thomas J. Logan

Evaluation of canisters for measuring emissions of volatile organic air pollutants from hazardous waste incineration

Regulation to control air emissions of toxic organic compounds require the collection and analysis of effluent gas from low level sources such as hazardous waste incinerators. The standard SW-846 Method specifies the use of Tenax and Tenax/charcoal adsorbent traps for collection of volatile organics from incinerators. This study evaluates passivated stainless steel canisters as an alternative to adsorbent traps to eliminate some of the problems associated with adsorbent sampling. Initially the stability of 18 nonpolar, volatile organic compounds was determined in Summa-treated stainless steel canisters with greater than 100 ppmv HCl and saturated with water vapor. All 18 components were stable for a two-week period; however, an interference caused a 10-fold increase in the FID response of trichloroethylene, toluene, and chlorobenzene. No interference of the ECD response was found for any of the 11 compounds detected with the ECD including trichloroethylene. A pilot scale incinerator was sampled using canisters, and the destruction efficiency of 1,1,1-trichloroethane was determined at a concentration of less than 0.5 ppbv while determining 1,1-dichloroethylene, the major product of incomplete combustion, at a concentration of 8000 ppbv from the same sample.

Sampling and Analysis Experiments for Improved Characterization of Products of Incomplete Combustion

Laboratory and field experiments were conducted to evaluate the volatile organic sampling train (VOST) methodology for the sampling and analysis of products of incomplete combustion (PICs). A pilot-scale incinerator was used to incinerate several volatile chlorinated organic compounds which were known to produce PICs. Approximately 300 ppm of 1,2-dichloroethane, 1,1,1-trichloroethane, and trichloroethene were individually incinerated at 700°C. Standard VOST sampling apparatus was used to collect samples for determinations of precision and for distributive volume-studies. A series of experiments was conducted to establish whether PICs were being formed at concentration levels which could be measured by the VOST methodology. Samples were collected at 1 L/ min for 20 min with standard pairs of Tenax-Tenax/charcoal cartridges. The major PICs found were vinyl chloride from 1,2-dichloroethane, 1,1-dlchloroethene from 1,1,1-trichloroethane, and carbon tetrachloride from trichloroethene. Chloromethane was also fo...

Performance Audit Results Using EPA Method 25 During Source Compliance Tests

The U.S. Environmental Protection Agency (EPA) has recently promulgated a revised Method 25, “Determination of Total Gaseous Nonmethane Organic Emissions as Carbon,” for volatile organic compound emissions from stationary sources. The method currently requires an analysis of a set of two audit samples concurrently with any compliance source test samples and in exactly the same manner to evaluate the sample collection and subsequent analysis technique. EPA has established a Method 25 audit material repository that is available to federal, state, and local agencies or their contractors for use in performance audits during source compliance testing. Two types of audit approaches for EPA Method 25 have been developed. The first approach uses commercially available gas cylinders containing known concentrations of selected volatile organics and carbon dioxide in an inert balance gas of nitrogen. A second approach Involves the use of a stainless steel cartridge containing a solid sorbent (Tenax®) spiked with kno...

A new audit method for EPA reference method 6

A simple, inexpensive, and accurate method for evaluating and/or auditing sampling and analytical phases of the EPA Source Reference Method 6 was developed. The method uses a known amount of a chemical compound in the form of a tablet or pill (or placed in a capsule) to generate sulfur dioxide quantitatively by reaction with an acid. The reaction takes place in a compact glass impinger system that can be taken to the field. The S02 generated in test runs was collected and analyzed using the Method 6 procedure. The SO2 generation was quantitative and recoveries were found to be 94 ± 5 %. The time to complete the reaction was less than 15 min at a flow rate of 1 L/min, but the recommended sampling time was 45 min. The tablets prepared gravimetrically were found to be stable over a sixmonth period. The interlaboratory results obtained showed close agreement with the expected concentrations based on calculations from the stoichiometric reaction. The estimates of repeatability (or within-laboratory precision) ...

An Assessment of the Long-Term Performance of Gas Continuous Emission Monitoring Systems

A field test program was conducted to evaluate the long-term performance of several gas continuous emission monitoring systems (CEMS).* This paper presents the results gathered on the long-term accuracy and calibration drift characteristics of ten CEMS installed at scrubber-controlled, coal-fired power plants. The program involved periodic accuracy audits and a review of available calibration drift data for selected CEMS. Accuracy audit results show that both SO2 and NOx CEMS are capable of providing accurate data on a long-term basis. However, frequent audits are necessary in order to verify the performance of an individual CEMS. The results of the calibration drift data evaluation show that despite infrequent occurrences of excessive drift, CEMS operated with a significant bias for extended time periods simply because corrective action was not taken in a timely manner.

Validation Studies of the Protocol for theVolatile Organic Sampling Train

The measurement of volatile organic emissions from a hazardous waste incinerator is one of the more difficult source testing problems. Specific compounds called principal organic hazardous constituents (POHC) are to be identified and quantified at levels of 0.5 to 100 ppb in hot, wet incinerator exhaust gas, which may also contain high particulate and acid levels. The Volatile Organic Sampling Train (VOST) Protocol which describes the practices used by laboratories making these measurements allows for several alternative designs and operating procedures. Because its use is currently being recommended by regulatory agencies to measure emissions for compliance determinations, the VOST Protocol was subjected to a methods validation study. The VOST Protocol validation program consists of two phases: a laboratory validation and a field test validation. The laboratory validation examined the results of sampling six different POHCs at two different concentration levels, two tube configuration designs, two moistu...

Calibration and certification of audit devices for transmissometers

This paper describes the procedures followed by the US Environmental Protection Agency, Environmental Monitoring Systems Laboratory, Research Triangle Park, NC, to certify the correct opacity to the neutral density (ND) filters for calibration of transmissometers. The term neutral density is applied to filters that have the ability to attenuate an incident beam of radiation without altering its spectral distribution over the visible range (380-770 nm). The actual certification process involves the scanning of the ND filter over the visible light energy range using a spectrophotometer. For this purpose, a conventional Cary Model 14 spectrophotometer was obtained and modified to improve the method of recording and processing data. A system was installed that converts the analog response of the spectrophotometer to a digital signal, which is then computer processed and a certification report automatically generated. The procedures for scanning the filter and the calculation algorithms to compute the luminous transmittance were adapted from procedures used by the National Bureau of Standards (NBS).

Validation of an Audit Material for EPA Method 6B

A simple audit material for EPA Method 6B was developed in a compressed gas cylinder and validated at three different laboratories. The audit mixture of CO2 (10 percent) and SO2 (250 ppm) in a balance gas of nitrogen prepared in aluminum cylinders was found to be stable over a 1-year period. The interlaboratory results obtained for the audit mixture using EPA Method 6B procedures showed reasonable agreement (SO2 and CO2 are within 7.5 percent and 5.3 percent, respectively) with EPA-measured concentrations except in one case, which was probably due to some contamination in the laboratory. A second audit material which uses chemical reactions to generate SO2 and CO2 was also developed. However, this approach was discontinued because it was difficult to simultaneously generate ppm levels of SO2 and percent levels of CO2 by chemical reactions in the field.

A New Audit Technique for EPA Method 25

A simple, inexpensive, and accurate technique for evaluating or auditing the sampling, recovery, and analytical phases of EPA Source Reference Method 25 has been developed. The technique involves spiking a U-shaped stainless steel cartridge containing Tenax® with known quantities of selected organic compounds and thermally desorbing them at temperatures from 160°C to 180°C to generate organic vapors quantitatively. The major advantages of this technique are that no other measurement methods can be used to determine the generated organic concentrations in lieu of Method 25; and that the cartridge can easily be taken to the field for evaluation. The organic compounds generated in test runs are collected and analyzed using the Method 25 procedure. The generation of organics is quantitative and recoveries were found to be 100 ± 10%. The time required for desorption of the majority of organics is generally less than forty-five minutes at a flow rate of 100 mL/min; however, based on laboratory experience the re...

Field validation of EPA proposed method 108 for measurement of inorganic arsenic emissions from stationary sources

The U.S. Environmental Protection Agency’s proposed Method 108 for measurement of inorganic arsenic emissions from stationary sources has been evaluated both in the laboratory and in the field. Field studies, which are the focus of this paper, Included determination of the precision of the sampling method using concurrent dual or quad sampling trains in the measurement of inorganic arsenic emissions from a copper smelter plant and a glass manufacturing plant. Results of the field tests indicate that the precision was 3.85 % at the glass plant and 15.7% at the copper smelter. Considering the sampling sites and the variability of process operations, these results Indicate an acceptable degree of precision.