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Myths And Facts

Myths vs. Facts About Energy Recovery in Cement Kilns

In the past, opponents of energy recovery in cement kilns circulated documents aimed at misinforming the public about cement kiln recycling technology.  Most of the outdated and inaccurate information in those documents originated as part of a public relations campaign targeted against cement kilns that recover energy from hazardous waste.  The campaign was launched in the 1990s by a defunct entity --- the Association for Responsible Thermal Treatment (ARTT), which was a front for several commercial hazardous waste incineration companies that saw cement kilns as a competitive threat and sought to discredit them.  Although ARTT and most of the incineration companies who funded it no longer exist, a surprising amount of the outdated misinformation and false claims they distributed remain in circulation.  For that reason, CKRC provides the following factual information to counter the persistent myths that are the legacy of this unfortunate episode.

MYTH:  Cement Kilns Emit Higher Levels of Metals and Chlorine than Incinerators

  • Some alternative fuels burned in cement kilns are derived from fuel-quality hazardous wastes that typically have significantly lower levels of metals and chlorine than the wastes that are burned for destruction in incinerators.  In addition, the USEPA stringently regulates emissions of hazardous air pollutants from hazardous waste combustors, such as incinerators and cement kilns.  In accordance with the Clean Air Act, these Maximum Achievable Control Technology (MACT) emission limits are set at the levels achieved by the best-performing technologies in each source category and they regulate emissions of many hazardous air pollutants, including metals and chlorine, at very low levels.

MYTH:  Cement Kilns are a Major Source of Dioxin

  • The cement industry has been very successful in reducing its emissions of dioxins & furans.  The industry invested in research to understand the nature of dioxin formation in combustion emissions and succeeded in learning how to control and reduce those emissions.  As a result, since 1990, dioxin emissions from kilns that recover energy from hazardous waste have been reduced by 99.3%.  (To learn more, click here.)  The cement industry’s research, which was corroborate by EPA research, also revealed that the formation of dioxins in a post-combustion reaction that is unrelated to whether a kiln uses hazardous waste as fuel.

MYTH:  Cement Kilns are not Regulated as Stringently as Incinerators or Other Industries

  • The combustion of hazardous waste in cement kilns has been regulated by USEPA since 1991. Those initial health-based regulations under the Resource Conservation & Recovery Act (RCRA) have been succeeded by much more stringent technology-based standards to under the Clean Air Act, which limit emissions of hazardous air pollutants.  Both cement kilns and incinerators are subject to these Hazardous Waste Combustor NESHAP standards
  • These rules, also called Maximum Available Control Technology (MACT) standards, contain strict technology-based limits on emissions of particulate matter and hazardous air pollutants such as metals, dioxins, chlorine, hydrochloric acid, carbon monoxide and hydrocarbons.  The Clean Air Act requires EPA to set these emission limits at the level of performance achieved by the average of the best 12% of sources within each category.  By definition, therefore, all hazardous combustors are regulated at equally stringent levels.

MYTH:  Cement Product is Affected by Recovering Energy from Alternative Fuel

  • The quality of cement product and the environmental properties of cement kiln dust by-product are unaffected by the type of fuel used to fire the kiln.  In 1995, EPA considered the question of whether cement product quality was affected by the use of waste-derived fuel (WDF) and concluded that "It is not substantiated that burning WDF increases risks posed to end users of cement."  (EPA response to TSCA petition - Fed. Reg. July 24, 1995.)  EPA also extensively investigated cement kiln dust adn concluded in 1993 that cement kiln dust is a high volume/low toxicity material that is not significantly affected by the use of alternative fuel.  (Report to Congress on Cement Kiln Dust, Vol. 1, December 1993)

MYTH:  Energy Recovery from Waste Increases Risks to Environment

  • Owners of cement kilns that use hazardous waste as fuel and government agencies have both conducted numerous risk assessments that have examined and evaluated every conceivable direct and indirect human exposure pathway to emissions from kilns. Some of these risk assessments also factored-in the aggregate effects of multiple cement plants and other industrial facilities operating within a single geographic region. The results of each risk assessment have shown that the regulated use of hazardous waste as fuel in cement kilns poses no increased risk to human health and the environment.  Additionally, before promulgating its latest MACT standards, EPA conducted extensive risk analysis to evaluate the protectiveness of those standards as well as current emissions levels. EPA concluded that current operations pose no unacceptable risk to human health and that future operations also will pose no unacceptable risk.
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