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7.0 PROCEDURE <br /> 7.1 Preliminary Evaluations <br /> Perform preliminary TCLP evaluations on a minimum 100 gram aliquot of <br /> waste. This aliquot may not actually undergo TCLP extraction. These preliminary <br /> evaluations include: (1) determination of the percent solids (Section 7.1.1) ; <br /> (2) determination of whether the waste contains insignificant solids and is , <br /> therefore, its own extract after filtration (Section 7.1.2) ; (3) determination <br /> of whether the solid portion of the waste requires particle size reduction <br /> (Section 7.1.3) ; and (4) determination of which of the two extraction fluids are <br /> to be used for the nonvolatile TCLP extraction of the waste (Section 7.1.4) . <br /> 7.1.1 Preliminary determination of percent solids: Percent <br /> solids is defined as that fraction of a waste sample (as a percentage of <br /> the total sample) from which no liquid may be forced out by an applied <br /> pressure, as described below. <br /> 7.1 .1 .1 If the waste will obviously yield no liquid when <br /> subjected to pressure filtration (i .e. , is 100% solids) proceed to <br /> Section 7. 1 .3. <br /> 7. 1 .1 .2 If the sample is liquid or multiphasic, <br /> liquid/solid separation to make a preliminary determination of <br /> percent solids is required. This involves the filtration device <br /> described in Section 4.3.2 and is outlined in Sections 7. 1.1.3 <br /> through 7.1.1.9. <br /> 7.1. 1 .3 Pre-weigh the filter and the container that will <br /> receive the filtrate. <br /> 7.1. 1 .4 Assemble the filter holder and filter following <br /> the manufacturer's instructions. Place the filter on the support <br /> screen and secure. <br /> 7.1 . 1 .5 Weigh out a subsampl e of the waste (100 gram <br /> minimum) and record the weight. <br /> 7.1 . 1 .6 Allow slurries to stand to permit the solid <br /> phase to settle. Wastes that settle slowly may be centrifuged <br /> prior to filtration. Centrifugation is to be used only as an aid <br /> to filtration. If used, the liquid should be decanted and filtered <br /> followed by filtration of the solid portion of the waste through <br /> the same filtration system. <br /> 7. 1 .1 .7 Quantitatively transfer the waste sample to the <br /> filter holder (liquid and solid phases) . Spread the waste sample <br /> evenly over the surface of the filter. If filtration of the waste <br /> at 4 °C reduces the amount of expressed liquid over what would be <br /> expressed at room temperature then allow the sample to warm up to <br /> room temperature in the device before filtering. <br /> CD-ROM 1311- 7 Revision 0 <br /> July 1992 <br />