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1 <br />Perform preliminary 1312 evaluations on a minimum 100 gram aliquot of <br />r sample. This aliquot may not actually undergo 1312 extraction. These <br />preliminary evaluations include: (1) determination of the percent solids (Step <br />' 7.1.1); (2) determination of whether the waste contains insignificant solids and <br />is,, therefore, its own extract after filtration (Step 7.1.2); and (3) <br />determination of whether the solid portion of the waste requires particle size <br />reduction (Section 7.1.3). <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 sample will obviously yield no free <br />liquid when subjected to pressure filtration (i_e., is 100 <br />solids), weigh out a representative subsample (100 g minimum) and <br />proceed to Step 7.1.3. <br />1 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 />discussed in Step 4.3.2, and is outlined in Steps 7.1.1.3 through <br />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 filter holder and filter following the <br />' ~ manufacturer's instructions. Place the filter on the support <br />screen and secure. <br />' 7.1.1.5 Weigh out a subsample of the waste (100 gram <br />minimum) and record the weight. <br />' 7.1.1.6 Allow slurries to stand to permit the solid phase <br />to settle. Samples that settle slowly may be centrifuged prior to <br />' filtration. Centrifugation is to be used only as +rn aid to <br />filtration. If used, the liquid should be decanted an~i 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 sample to the filter <br />holder (liquid and solid phases). Spread the sample e~~enly over <br />' the surface of the filter. If filtration of the waste at 4'C <br />reduces the amount of expressed liquid over what would be expressed <br />at room temperature, then allow the sample to warm up to room <br />temperature in the device before filtering. <br />NOTE: If sample material (>1 percent of original sample weight) has obviously <br />' adhered to the container used to transfer the sample to the Filtration <br />apparatus, determine the weight of this residue and subtract it from the <br />sample weight determined in Step 7.1.1.5 to determine the weight of the <br />sample that will be filtered. <br />'• <br />1312 - 7 Re•/ision 0 <br />' No~rember 1990 <br />