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May 3, 1999 <br /> To: Glenn Mallory, Roger Doak <br /> From: Ken Niswonger <br /> Re: Comments on Varra Coal Ash Burial Project <br /> 1. Composition data on various ashes are provided in the Work Plan Analytical Data document; <br /> however, it is not known from sample descriptions which, if any, are the composition data for the <br /> ashes actually used in the leachate tests. For example, leachate data are presented for a material <br /> named "Bottom Ash", but there are compositional data for bottom ash from the Cameo, <br /> Arapahoe, Cameo #2, and Comanche units. The fly ashes used and named in the leachate tests <br /> cannot be reconciled with compositional data because the sample designations appear to differ <br /> with leachate sample designations. <br /> 2. According to the information provided by the power industry regarding ash material and the <br /> manner of generation of ash material considered for the Final Regulatory Determination of Large <br /> Volume Wastes From the Combustion of Coal by Electric Utility Power Plants (Federal Register, <br /> Vol. 58, No. 151), the manner of generation of these wastes typically involve commingling of <br /> bottom ash, fly ash, and possibly, with low volume wastes ranging from plant water to boiler <br /> chemical cleaning wastes. To assist in the evaluation of data generated by the proposed tests as <br /> they are applicable to the universe of potential ashes which may be represented by these data, <br /> please describe the generation, and management of the materials considered for disposal in the <br /> saturated environment present at the Varra Coal Ash Burial Project. <br /> 3. The Synthetic Groundwater Leaching Procedure (SGLP), where the samples were rolled for <br /> 18 hours in contact with groundwater from the site, does not provide the chemical characteristics <br /> (e.g., pH, Carbonate/Bicarbonate concentrations) of the groundwater prior to, or following these <br /> extraction tests. Furthermore, only one extraction was conducted on ash materials using the <br /> SGLP method. The SGLP results appear to produce dramatically lower concentrations of the <br /> principal metal ions (Al, Ba, Cr, Fe, Mg) and, trace metal ions (Be, B, Cd, Co, Pb, Se, V, Zn, and <br /> Li) as compared to the Sequential Extraction Leaching Procedure (SELP) at pH 5, 7, or 8.5. It is <br /> not apparent that these observable differences are related to actual chemistries of the <br /> groundwater, or whether the number of extractions performed on ashes using the SGLP <br /> procedure contributes to these differences. The SGLP was conducted following the TCLP <br /> method and substituting groundwater for the extraction fluid. <br />