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GSI sends coal ash comments, data to EPA

News | November 18, 2010 | By:

Editor’s note: Following is a letter from Geosynthetic Institute Director Robert Koerner to the U.S. Environmental Protection Agency. The content includes comments and data in support of alternative liner systems for disposal of coal combustion residuals (“coal ash”).

The letter was sent to all GSI members and associate members, and is reprinted here with permission.
— Ron Bygness, editor, Geosynthetics

Geosynthetic Institute
475 Kedron Avenue
Folsom, PA 19033-1208 USA
TEL (610) 522-8440
FAX (610) 522-8441

November 16,2010

Office of Resource Conservation and Recovery
United States Environmental Protection Agency
Washington, DC 20460

Re: Submittal of Comments and Data in Support of Altemative Liner Systems Disposal of Coal Combustion Residuals (CCR) From Electric Utilities; Proposed Rules
Federal Register, Vol. 75, No. 118, June 21,2010
Docket ID No. EPA-HQ-RCRA-2009-0640

Dear Sir/Madam:

The opportunity of commenting on the proposed EPA Regulations for Coai Combustion Residuals is appreciated particularly since the implications of one aspect of the draft terminology is so misieading and as such, inappropriate. Let me explain.

I and my institute (which have been funded by U. S. EPA at Drexel University since 1975) have been intimately involved in liner regulations throughout their regulatory history. Beginning with RCRA in 1982 it was recognized that a composite liner consisting of an FML above a CCL (compacted clay liner) was felt to be the optimal barrier material for both the liner beneath and the cover above the waste mass.

As individual states began implementing these regulations the lack of low permeability clay soils in many geographic regions of the country became a major economic burden for landfill owners. These geographic areas are the heavy popuiated Middle Atlantic, New England and West Coast regions of the country. A replacement for the CCL component of a composite liner in the form of a FML above a geosynthetic clay liner (GCL) appeared in 1985. Since then GCL’s have replaced CCL’s in seventeen states* and at this point in time a FML/GCL is the de-facto composite liner system for solid waste barriers in these states, i.e., there is no CCL component at all!

As a result, your tentative requirement of a FML/CCL barrier with “no alternatives” is incorrect and inappropriate. It is also frightfuily expensive due to transportation and placement of the CCL which is the reason for using FML/GCL systems to begin with. Clearly, in these seventeen states (which happen to be the most populous having the largest amounts of CCR to deal with) FMLIGCL systems are not “alternative” liner systems. ln fact, they are the primary and only liner systems being installed for both liners beneath solid waste and covers above such materials.

While I understand the logic behind not using alternative liner systems of a new and untried nature, clearly FML/GCL’s do not fall into this category. FML/GCL’s are the liner systems of choice in all states without an abundance of natural low permeability clay soil within reasonable transportation distances.

Furthermore, in this era of sustainability concerns, the carbon footprint of transporting many heavy truckloads of clay versus a very few rolls of GCL’s is a mismatch of the highest order. The following illustration makes this point abundantly clear.

150 Truckloads of Clay = 1 Truckload of GCLs 150 Truckloads of Clay = 1 Truckload of GCLs

In summary, FML/GCL’s are not alternative liner systems and should not be considered as such since they are the liner system of choice in many states and are required and regulated accordingly.

Very truly yours,

Robert M. Koemer, Ph.D., P.E., NAE
Emeritus Professor of Civil Engineering — Drexel University
Director — Geosynthetic Institute/Website

*GRI Report #32, R. M. Koerner and J. R. Koemer, “GRI’s Third Survey of Solid Waste Landfill Liner and Cover Systems: Part I – USA Status”, January 12, 2007.

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