My understanding of the CEMEX proposal is that, with respect to the use of tire-derived fuel, up to 20% of the Btu value currently derived from combustion of coal in the kiln would be replaced by tires, with the tires being fed either whole or in shredded form into the kiln. Additionally, CEMEX is considering the use of pelletized sludge from the Metropolitan Sewer District, which would be introduced into the burn chamber with the coal rather than into the kiln.
Initially, let me express my appreciation for the solicitation of input from the residents of the Kosmosdale / Valley Village area early in the process, and the commitment to continued dialogue with the community. It is my hope that, through continued dialogue concerning the proposals, an outcome that is beneficial to both the economic health of CEMEX and the public health of the host community can be achieved. Towards that end, KRC has summarized our concerns and requests for information below.
Let me begin by summarizing KRC’s historic and current position regarding the use of waste tires as a fuel. KRC has not categorically opposed such use, but has expressed two concerns – one, a concern with the protection of public health in the technical aspects of the sourcing, transportation, storage, use and waste disposal associated with such use; and the second a policy concern regarding whether the use of waste tires as a fuel is the highest and best use of such wastes.
With respect to the first issue, KRC has historically opposed proposals to combust tires that lack appropriate monitoring and engineering design and pollution controls to assure public protection under all combustion conditions. The combustion of waste tires is not a matter lightly undertaken, and there are sound policy reasons why burning tires should be carefully regulated under stringent controls.
As you know, tires are a complex mixture of organic chemicals and metals, and burning tires creates toxic air emissions. Emissions from upsets, and poor unit operation as well as from steady-state operation may contain a host of chemicals and compounds that are of concern and must be managed properly because of their known or suspected health consequences.
Some of the compounds of concern include these:
* VOCs (volatile organic chemicals) such as benzene, chloroform, 1,2-dichloroethane (1,2 DCE), hexachlorobenzene, methylene chloride (MC), styrene, toluene, and trichloroethylene (TCE);
* A number of polycyclic aromatic hydrocarbons (acenapthene, acenapthylene, benzo(a)pyrene, benzo(g,h,i)perylene, benzo(k)fluoranthene, fluoranthene, fluorene, phenanthrene and pyrene), a list including chemicals for which there is evidence of human mutagenicity, and other potential human health consequences;
* A number of metals of concern because of their cancer-causing potential and other health effects, including zinc, aluminum, lead, chromium, and arsenic.
* Dioxins and furans; and
* Particulate matter.
In addition, specific rubber components such as butadiene and styrene have also been found in emission gases. Benzene, chloroform, 1,2-DCE, MC and TCE are known or suspected cancer-causing agents, as are lead, chromium and many of the PAHs. Butadiene is considered as a very potent liver carcinogen. Dioxins are considered among the most toxic chemicals ever tested. In addition to these products of combustion, the incomplete combustion produces new chemicals that were not in the original waste, called “PICs” or products of incomplete combustion. Dioxins and furans are in this category, and are likely to be found because many of the chemicals in tires contain chlorine.
For these reasons, any proposal for use of waste tires as fuel must fully characterize the range of organics and metals emissions and assure that there are no adverse public health effects from emissions under steady-state and upset conditions, and must include strict controls on the combustion process and continuous monitoring to assure limits on total metals loading through more restrictive particulate standards, organics, and acid gases as well as on combustion efficiency (CO). Because the chlorine and metal content varies from tire to tire, maintaining combustion efficiency can be a problem that required careful attention. A multipath risk characterization and thorough air toxics analysis that considers the emissions under steady-state and malfunction conditions is advisable.
Against this background, KRC requests the following information to the extent that it is available:
a. What are the percentages of ash content, combustibles, volatiles, carbon and hydrogen?
b. What is the average heat value of the coal in BTUs and MJ/kg?
c. For which emission parameters does Cemex currently monitor, and, if not continuously, at what frequency basis? By what method does it monitor NOx and SOx?
d. At what rate does Cemex propose to input tires into the kilns or calciners? At what temperatures? For how long of a detention time?
e. What changes in emissions of the pollutants of concern mentioned above does Cemex expect if waste tires are added to its fuel mix? Please provide related research or trial burn results supporting that expected change.
f. Are upset or malfunction conditions a concern regarding the use of waste tires, and how are such conditions controlled?
g. What change in the volume or composition of waste ash or wastewater is anticipated?
h. What will be the source(s) of the tires? What volume of tires is anticipated to be used, and to be stored on site at any one time?
i. What will be the frequency of shipments, and how will the tires be stored on site and managed to avoid the possibility of tire fires and creation of stagnant water conditions that could contribute to breeding of mosquitoes?
j. Has a market survey been conducted on the availability of tires for use as fuel? What is the current disposition of the tires that would be used as fuel by CEMEX?
k. Will CEMEX consult with KRC and other concerned citizens groups concerning the development of the trial burn plan prior to submittal of the plan for agency review?
l. Will CEMEX consult with KRC and other concerned citizens groups prior to requesting a determination of consistency with the county solid waste plan, and will CEMEX request such a determination of consistency?
Use of Biosolids As Fuel
I understand based on our discussion that CEMEX is also considering, and seeking public input on, the possible use of the palletized sludge generated by MSD to substitute for a percentage of the coal now utilized as fuel in the kiln. The same policy and technical questions arise in the proposed use of this processed waste product as a fuel.
Based on KRC’s preliminary research, the use of biosolids as an alternative fuel by the Lehigh Cement Company, in 2004 at a rate of 3 T/hr (11% of the calciner fuel, or 6% of the system fuel), resulted in additional wear on the equipment (due to abrasive nature of dried biosolids), over-fueling, “moisture issues” and “flow issues.”
Compared to coal only, the addition of biosolids raised heat input by 6%, raised NOx by 13%, slightly lowered CO and HC by 3% each, and reduced SOx by 35%. Since that trial run, per this presentation, they’ve combusted biosolids at rates as high as 15 T/hr, with no adverse affects on product quality and with emissions similar to that of coal combustion.
Leaving aside the policy concerns that using MSD’s biosolids as a fuel may be viewed as other than the highest and best use of a product that represents a significant investment in ratepayer-dollars and energy resources in the production of an Exceptional Quality, Class A fertilizer, KRC has these preliminary questions:
a. What are the percentages of ash content, combustibles, volatiles, carbon and hydrogen in the biosolids proposed to be used as alternative fuel?
b. What are the average moisture content and heat value of the biosolids proposed to be used as alternative fuel in BTUs and MJ/kg?
c. To the extent CEMEX knows, what tonnage of biosolids have been produced for sale or beneficial use since the Alternative Solids Processing facilities went on line.
d. Has CEMEX reviewed the analyses required by the §503 regulations and Commonwealth of KY permit for MSD’s biosolids.
e. Has CEMEX reviewed the MSD fertilizer reports submitted to the KY Division of Regulatory Services?
f. Will selling MSD’s biosolids for alternative fuel allow reduced processing of the biosolids by MSD or will it purchase the product as currently treated? If so, which operations will be reduced or eliminated?
g. Has CEMEX engaged in discussions with MSD concerning the availability of the biosolids? Will Cemex pay MSD for biosolids? If so, how much?
h. Will MSD maintain its pretreatment program if its biosolids will be combusted in cement kilns?
i. What is the current use or fate of the biosolids proposed for use by CEMEX?
j. How will biosolids be received and stored, and how will odors from the receipt, storage and use be managed?
k. What percentage of the fuel mix will biosolids comprise, by tonnage and Btu value?
l. Will biosolids be introduced in conjunction with tires?
m. What is the emission profile for the range of tire – biosolid and coal mixes contemplated, and the basis for the estimated emissions?
n. What variability in moisture, metals, chlorine and other constituents is anticipated in the inputs, and how will that be monitored and managed to assure proper combustion and control of all emissions.
o. Will CEMEX consult with KRC and other concerned citizens groups concerning the development of the trial burn plan prior to submittal of the plan for agency review?
p. Will CEMEX consult with KRC and other concerned citizens groups prior to requesting a determination of consistency with the county solid waste plan, and will CEMEX request such a determination of consistency?
Thanks in advance for your consideration of these concerns and your response to these inquiries. KRC looks forward to continued dialogue with CEMEX about these proposals.