1999-04-12_HYDROLOGY - M1974052 (7)

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1 1 1 1 1 1 1 ccxs, m~. 2.0 INITIAL LABORATORY TESTING Public Service Company generated analytical data indicating that fly ash is not a characteristic hazardous waste. Numerous analytical methods were used such as toxicity characteristic leaching procedure (TCLP). CGRS in conjunction with Colorado State University Groundwater Program performed a number of tests that included: • Hydraulic Conductivity Testing (Permeameter Test); • Porosity Determination; • Sequential Extraction Leaching Procedure (SEEP); • Synthetic Ground Water Column Leaching Procedure (SGCLP); • Toxic Characteristic Leaching Procedure (TCLP); and • Synthetic Ground Waler Leaching Procedure (SGLP). A discussion of these tests is provided below. ' 2.1 Hydraulic Conductive The hydraulic conductivity of the ash was performed using either a "Constant Head" or "Falling ' Head" Permeameter. The Constant Head Permeameter works better for high permeability porous materials and the Falling Head Permeameter works best for low permeability porous materials. ' With either test the flow rate and the potentiometric head loss are measured through a sample of ~~;,, the ash. The hydraulic conductivity was then calculated using Darcy's Law. The hydraulic n "'"~ ``.. . ' conductivity of the ash is requtred to determine the expected rate of groundwater flow through the buried ash and the effects of burial on ground water flow patterns. 2.2 Porosity ' Porosity is the ratio of the volume of the voids to the bulk volume of the sample. With this test the volume and dry weight of a sample of ash was measured. The ash was then saturated with water ' under a vacuum pressure and the weight of the saturated sample measured. For saturated conditions the volume of the voids is equal to the volume of the water. The porosity is required to~ ' I determine the pore volume for the ash. The results of hydraulic conductivity and porosity testing are summarized in Table I . J 1 1 3