KRC Comments on Permit For East Kentucky Power John Sherman Cooper Coal Combustion Waste Landfill Posted: October 19, 2012
Ronald Gruzesky, P.E.
Division of Waste Management
200 Fair Oaks Lane
Frankfort, Kentucky 40601
Re: Draft Permit
John Sherman Cooper Landfill
AI 3808 / Permit 100-00015
Dear Mr. Gruzesky:
These comments are submitted on behalf of the membership of the Kentucky Resources Council, Inc., a nonprofit environmental advocacy organization incorporated under the laws of the Commonwealth of Kentucky and dedicated to prudent use and conservation of the natural resources of the Commonwealth. The Council has reviewed the draft permit authorizing the addition of another 55.58 acres of disposal area to the existing facility for the disposal of fly and bottom ash, and FGD and Clarifier Sludge, and has these concerns.
A key to the proper functioning of the Kentucky special waste regulations is that the chemical and physical properties of the special waste be adequately characterized utilizing the appropriate testing methods, in order to determine what constituents are present in the waste streams that may become liberated, under the intended disposal conditions, through interaction with rainfall and any leachate recirculated for dust control.
To the extent that the TCLP test protocol has been utilized to identify potential constituents that might leach from the waste(s), the characterization is inadequate, since the TCLP test was intended to replicate field conditions for a “contained” or municipal solid waste landfill, whose leachate pH and in situ environmental conditions are not comparable to disposal in a special waste landfill accepting fly and bottom ash, FGD and clarifier wastes.
The draft permit should be withdrawn pending the submittal of test results utilizing appropriate protocols that replicate actual field conditions for the disposal facility, a demonstration that the proposed liner and leachate collection system is satisfactory to meet the applicable environmental protection standards for special waste land disposal, and the imposition of surface and groundwater monitoring parameters sufficient to detect any release of the constituents of concern from the landfill.
The TCLP test method is not appropriate for predicting leachability of coal combustion wastes in monofills. The TCLP (Toxicity Characteristic Leaching Procedure) is the EPA test method used to evaluate the leachability of metals, organic compounds and pesticides from wastes into groundwater under one set of disposal conditions – co-disposal of CCW in a municipal solid waste landfill. The TCLP is a batch test developed by EPA in response to deficiencies in an earlier test, the Extraction Procedure (EP) toxicity test. Many of the assumptions used in developing the EP were retained, however, and the TCLP is widely considered to have serious limitations.
In principle, the TCLP simulates the leaching of constituents from the waste into groundwater under conditions found in a municipal solid waste landfill. However, the TCLP has been applied to wastes in disposal and management settings other than municipal waste co-disposal.
The EPA’s Science Advisory Board has criticized the TCLP protocol on the basis of several technical considerations, including the test’s consideration of leaching kinetics, liquid-to-solid ratio, pH, potential for colloid formation, particle size reduction, aging, volatile losses, and co-mingling of the tested material with other wastes (i.e., co-disposal). Specific limitations of the TCLP are:
* TCLP underestimates leachate from some high alkaline wastes or environments.
* TCLP underestimates the leachate concentrations from oily wastes and paint wastes.
* TCLP does not account for the conditions of waste disposed of in a monofill.
* TCLP may underestimate the chelation-facilitated mobility of some waste constituents.
* TCLP does not account for oxidation/reduction reactions occurring in landfills.
* TCLP may not predict the long-term mobility of organic constituents in some treated wastes.
* TCLP may not be appropriate for contaminated soil.
* TCLP does not predict releases to non-groundwater pathways.
The literature suggests that TCLP testing is generally insufficient to predict short-and long-term leaching characteristics of coal combustion fly and bottom ash. The use of short-term batch leaching tests, such as TCLP, EP-Toxicity, SPLP, and ASTM-D2987 (Shake Extraction) are not necessarily reflective of field conditions and long-term leaching potential. According to Ann Kim of the National Energy Technology Laboratory, “[t]he utilization of coal combustion by-products (CCB) as bulk fill and mine backfill has raised questions about the potential contamination of surface and groundwater. . . . Leaching is related to the solubility of a specific compound and can be influenced by pH, temperature, complexation, and oxidation/reduction potential. . . . Regulatory tests and standard methods are not necessarily appropriate for leaching tests intended to stimulate natural processes.”
Kim, CCB Leaching Summary: Survey of Methods and Results.”
As noted above, the TCLP test method is a batch test developed by EPA in response to deficiencies in an earlier test, the Extraction Procedure (EP). The test was designed as a screening test to consider conditions that may be present in a municipal solid waste (MSW) landfill. It is acetic acid buffered to pH 5 (initial); 20: 1 liquid/solid ratio; particle size reduction to 9.5 mm; equilibrium. The reason it was designed this way was because, under RCRA, EPA is required to regulate as hazardous all wastes that may pose a hazard to human health and the environment if they are mismanaged. . . . co-disposal of industrial solid waste with MSW is considered to be a plausible “worst-case” management of unregulated waste.
Helms, US EPA Leach Testing of Coal Combustion Residues.
As Gregory Helms with the EPA Office of Solid Waste explained, the EPA Science Advisory Board commented on the TCLP test method in 1991 and again in 1999, expressing concern “about overbroad use of the TCLP test.” Id. The SAB found that TCLP is a screening test that evaluates leaching potential under a single set of environmental conditions. The SAB has expressed concern over the use of the TCLP when it has been applied to determine the leaching potential of wastes in disposal settings other than municipal waste co-disposal has been criticized.
The U.S. EPA utilized a new multi-tiered testing framework in a research program designed to evaluate the potential for mercury release from various types of coal combustion wastes. The alternative framework evaluates the potential leaching of waste constituents over a range of values for parameters that affect the leaching potential. In explaining the EPA decision to utilize a leach testing approach developed by Kosson et al. at Vanderbilt in evaluating leaching from coal combustion residues resulting from mercury emissions controls, Helms explained that TCLP wasn’t used for evaluating coal combustion residues from enhanced mercury controls because “TCLP is not technically appropriate” where the disposal is not co-disposal with MSW.
Others have noted the limitations of the use of TCLP as an analytical method for predicting leaching potential of coal combustion wastes. Hassett notes that
"The TCLP is often used in a generic manner for the prediction of leaching trends of wastes, although the intent of this test was for the prediction of leaching under co-disposal conditions in sanitary landfills. The application of acidic conditions to predict field leaching that can occur under a wide range of conditions may lead to false prediction of leaching trends. Additionally, conditions imposed on leaching systems by inappropriate leaching solutions may alter the distribution of redox species that would be found in the field and, in some cases with reactive wastes, 18 hours, as specified in the TCLP and other short-term leaching tests, may be an insufficient equilibration time. In order for a batch leaching test to be used, in determining potential for environmental impact . . . when being used with CCBs, the test must take into account the unique properties of the material, especially the hydration reactions of alkaline CCBs."
Hassett and Pflughoeft-Hassett, Evaluating Coal Combustion By-Products (CCBs) For Environmental Performance.
Because the tests are not designed for use with CCBs, they do not account for several typical reactions in CCBs under hydration. It has long been known that laboratory leaching procedures cannot precisely simulate field conditions nor predict field leachate concentrations. However, with careful application of scientifically valid laboratory procedures, it is possible to improve laboratory-field correlations and modeling efforts focused on predicting leachate concentrations. Id.
Hassett recommends the development of a selection of laboratory leaching procedures that more closely simulate field management scenarios, focusing specifically on technical and scientific variables such as the long-term hydration reactions that can impact leachate concentrations of several constituents of interest, the means by which water contacts the CCB in order to simulate the reduced permeability frequently exhibited in CCB utilization applications, the impact of pH and other CCB properties on the leachate and on resulting leaching; and the prediction of, and changes in, leaching over time. Id. Hassett recommends use of Synthetic Groundwater Leaching Procedure with a long-term leaching (LTL) procedure as a better predictor of leaching under field conditions. His work reflects that “[I]n many applications, the extended-time SGLP “has demonstrated trends significantly different from TCLP and other commonly used leaching protocols.”
The explanation for the differing results and trends between the extended-time SGLP and TCLP “can be explained by the fact that many commonly used leaching tests impose conditions different from those in a field environment on samples, and, thus, bias data in a manner leading to inappropriate interpretation for environmental impact. Elements most often affected include arsenic, boron, chromium, vanadium, and selenium.” Id.
The EPA Report on Characterization of Mercury-Enriched Coal Combustion Residues from Electric Utilities Using Enhanced Sorbents for Mercury Control, EPA/600/R-06/008 (January 2006) further underscores both the importance of utilizing proper test methods for characterization of these coal combustion wastes, and the trend towards increasing potential toxicity of such wastes as air pollution controls better capture metals entrained in and released during combustion of the coal. Among the observations of the agency were that “arsenic and selenium may be leached at levels of potential concern from CCRs generated at some facilities both with and without enhanced mercury control technology [and that] further evaluation of leaching or arsenic and selenium from CCRs that considers site specific conditions is warranted.”
With respect to the sufficiency of TCLP, EPA noted that leaching tests “focused on a single extraction condition” would not have allowed for an evaluation of the variations in anticipated leaching behavior under the anticipated field disposal conditions.
The reliance on total metals analysis and TCLP data rather than on laboratory data that more accurately and adequately characterizes the leaching potential and “nonhazardous” nature of the wastes over the long-term, places the Cabinet and the permittee in a position where they cannot demonstrate with any degree of confidence that the containment for the disposal facility has been properly designed to address the potential for leaching constituents of concern. Coal combustion wastes may or may not prove to leach constituents of concern at below levels of both regulatory and environmental concern, but the reliance on TCLP and total metals test methods is insufficient to support such a finding for this permitting action. Appropriate longer-term leaching procedures, such as Kosson protocol, the LTL extended-time variant of the SGLP as described by Hassert and sequential leaching tests such as that described by Ziemkiewicz that leach the CCB with a sample of the water that will come into contact with the CCB (through surface infiltration of rainfall or groundwater) until the alkalinity is exhausted and the pH of the leachate returns to that of the encountered water. Such dynamic testing under a range of conditions will better predict the long-term leaching potential of these coal combustion wastes.
A study of a bituminous fly ash disposal site revealed that several different leaching tests, both column and shake extraction, failed to predict the contaminants found in the monitoring wells. The study found that leaching tests both over predict and under predict concentrations of pollutants and that results should be field tested until the leaching characteristics of the particular ash are fully known. The study found that leach tests are unreliable field indicators "primarily because these tests are not designed, and should not be used, to predict exactly the concentrations of leachate components that will be found in the field."
In sum, appropriate test methods for determining the short and long-term trends in leaching of constituents of concern from coal combustion wastes under this intended disposal method should be employed, and the TCLP method should not be allowed as the test for determining compliance with environmental performance standards in contexts other than the limited set of field conditions that the TCLP test was intended to replicate (i.e. co-disposal in municipal waste landfills).
Finally, with respect to the surface and groundwater monitoring conditions, the choice of parameters to sample must of necessity await full characterization of the constituents of public health and environmental concern that are identified as leaching from the wastes, utilizing appropriate testing protocols. Coal and CCW have been analyzed and characterized by a number of researchers, and the composition of coal and coal combustion wastes varies widely. According to Block and Dams (1976), the composition of fly ash is “significantly different from the original coal composition.” In comparison to coal, fly ash is relatively enriched in elements such as chlorine, copper, zinc, arsenic, selenium, and mercury (Block and Dams, 1976). According to Carlson and Adriano (1993), fly ash is also enriched in boron, strontium, molybdenum, sulfur, and calcium. Trace elements in the ash are concentrated in the smaller ash particle sizes. The disposal of CCW has caused a variety of environmental problems particularly to soils and waters, due to an extreme pH and high concentrations of soluble salts, trace metals and other pollutants that leach from different CCWs. Until the various waste streams proposed for disposal in the expanded disposal area are characterized individually and in the typical disposal “blend”, little confidence can be placed on the sufficiency of the proposed monitoign conditions.
Thank you in advance for your consideration of these concerns.