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Technical Papers

SARA 313 (TRI) Reporting Requirements for Dioxins (PCDD/PCDFs)
For a number of years, EPA SARA 313 reporting requirements for dioxin emissions and releases to the environment have caused confusion and difficulties among those attempting to comply with the rule.  Default emission factors as well as site-specific data have been used in an attempt to comply, but because of confusion over the specific requirements, over-reporting of dioxin emissions has been a common result.  The following provides specific guidance on how to properly perform these calculations and avoid or minimize the negative publicity that can result from over-reporting dioxins. MORE

A Review of Potential Solutions to Control Dioxin (PCDD/PCDF) Emissions from Cement Kilns
Cement kilns first focused on the need to control dioxin emissions as part of the BIF regulations over a decade ago.  More recently the Hazardous Waste Combustor (HWC) MACT and Portland Cement (PC) MACT regulations have imposed strict limits and testing requirements on all cement plants in the United States.  Numerous plants both in the U.S. and around the world have faced the “surprise” of needing to address dioxin emission measurements that were higher than expected – sometimes dramatically higher.  Potential control strategies based on actual experiences are reviewed in this paper. MORE

Factors Influencing Emission Levels of PCDD/PCDFs from Cement Kilns
As the Hazardous Waste Combustor MACT and Portland Cement MACT rules are implemented throughout the cement industry, extensive testing is providing further clarification of the factors in cement kiln operation and chemistry that impact PCDD/PCDF emissions. It is generally accepted that PCDD/PCDF emissions require time at temperature, a source of chlorine and a source of organic precursors. In cement kiln operations the source of organic precursors has been thought to be the raw material rather than fuel combustion. Additional data gathered in preparation of MACT compliance is used to examine this and related issues. MORE

Sources of PCDDS/PCDFs in Cement Kiln Emissions
This paper presents data on the source of PCDDs/PCDFs in cement plant stack emissions, demonstrating that these emissions are not necessarily all created by the process. The data demonstrates that some of the PCDDs/PCDFs in the emissions are pre-existing dioxins and furans that are vaporized out of the kiln raw feed. This calls into question the assumption that PCDD/PCDF emissions can be decreased below a certain point. The EPA has acknowledged resuspended PCDD/PCDF emissions, such as from forest fires, as a "reservoir source" of these emissions. Based on the data presented here, there may be a basis for an acknowledgement by the EPA of a site specific minimum level of PCDD/PCDF emissions attributable to the kiln feed raw materials as a "reservoir source." MORE

2,3,7,8-TCDD Equivalent Emissions from Cement Kilns Burning Hazardous Waste  Effective August 21, 1991 the United States Environmental Protection Agency (USEPA) adopted the Boiler and Industrial Furnace (BIF) rules which govern cement kiln operations burning hazardous waste fuel and set limits on cement kiln emissions of metals, HCL/chlorine and organics.  Dioxin testing was required to address the concerns of the USEPA arising from the review of stack test data from municipal waste combustion units. Dioxin emissions tests were developed and designed to meet EPA criteria under worst-case conditions and performed at 15 cement plants. Upon compilation of this data, an evaluation was performed for a correlation between HCl and Cl2 emissions and dioxin emissions. When no correlation was found, additional data analysis revealed a trend between the kiln exit temperature and dioxin emissions.  Additional data was gathered from selected cement plants and the available individual run data was plotted against temperatures at APCD device inlets. The dioxin emissions show a decrease in concentration as a function of decreasing temperature. This corresponds with EPA's concerns about dioxin emissions increasing as a function of stack or APCD temperatures.  MORE