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slowly out of the ZHE device into a hood. At the first appearance of <br /> liquid from the liquid inlet/outlet valve, quickly close the valve and <br /> discontinue pressure. If filtration of the waste at 4 °C reduces the <br /> amount of expressed liquid over what would be expressed at room tempera- <br /> ture, then allow the sample to warm up to room temperature in the device <br /> before filtering. If the waste is 100% solid (see Section 7.1. 1) , slowly <br /> increase the pressure to a maximum of 50 psi to force most of the <br /> headspace out of the device and proceed to Section 7.3.12. <br /> 7.3.9 Attach the evacuated pre-weighed filtrate collection <br /> container to the liquid inlet/outlet valve and open the valve. Begin <br /> applying gentle pressure of 1-10 psi to force the liquid phase of the <br /> sample into the filtrate collection container. If no additional liquid <br /> has passed through the filter in any 2 minute interval , slowly increase <br /> the pressure in 10 psi increments to a maximum of 50 psi . After each <br /> incremental increase of 10 psi , if no additional liquid has passed through <br /> the filter in any 2 minute interval , proceed to the next 10 psi increment. <br /> When liquid flow has ceased such that continued pressure filtration at 50 <br /> psi does not result in any additional filtrate within a 2 minute period, <br /> stop the filtration. Close the liquid inlet/outlet valve, discontinue <br /> pressure to the piston, and disconnect and weigh the filtrate collection <br /> container. <br /> NOTE: Instantaneous application of high pressure can degrade the glass <br /> fiber filter and may cause premature plugging. <br /> 7.3. 10 The material in the ZHE is defined as the solid phase of <br /> the waste and the filtrate is defined as the liquid phase. <br /> NOTE: Some wastes , such as oily wastes and some paint wastes, will <br /> obviously contain some material that appears to be a liquid. Even <br /> after applying pressure filtration, this material will not filter. <br /> If this is the case, the material within the filtration device is <br /> defined as a solid and is carried through the TCLP extraction as a <br /> solid. <br /> If the original waste contained <0.5q dry solids (see Section <br /> 7. 1 .2) , this filtrate is defined as the TCLP extract and is analyzed <br /> directly. Proceed to Section 7.3.15. <br /> 7.3.11 The liquid phase may now be either analyzed immediately <br /> (See Sections 7.3.13 through 7.3.15) or stored at 4 °C under minimal <br /> headspace conditions until time of analysis. Determine the weight of <br /> extraction fluid #1 to add to the ZHE as follows: <br /> 20 x percent solids (Section 7.1 .1) x weight <br /> of waste filtered (Section 7.3.4 or 7.3.8) <br /> Weight of extraction fluid = <br /> 100 <br /> CD-ROM 1311- 17 Revision 0 <br /> July 1992 <br />