Determination of total organic emissions from hazardous waste combustors

U.S. Environmental Protection Agency risk assessment guidance currently under development for evaluation of permitting information from hazardous waste combustors requires a quantity referred to as "total organic carbon". The risk guidance does not define this term precisely, nor does it explain how it should be determined. This paper discusses basic principles of sampling and analysis of stack emissions for "total organics", best currently available technology, and the status of two ongoing projects designed to provide guidance and to improve analysis procedures. Determination of total organics from stack emissions is much more complicated than might be expected, and more published guidance is badly needed. The best scheme available for analysis of stack emissions for total organics to be used in material balance style "bookkeeping" includes determination of organics content in three boiling point ranges:  <100 °C, 100 °C-300 °C, and >300 °C. Total organic carbon is not a useful quantity, since it includes soot, polymeric material, and other nonextractable organic materials. Total organics has been found to be an imperfect but less misleading term. Various calculations can be made and conclusions can be drawn on the basis of the contents of the individual boiling point ranges, as determined by the recommended methodology. The analysis strategy is complicated and difficult, and it contains limitations and compromises. It does not, however, require exotic analysis instrumentation, nor is it very expensive. Each of these facets of the methodology is discussed in this paper, and a status report is provided on development of a guidance document and a research project intended to produce improved methods.