Within EPA Method 1311, Section 2, Summary of Method, specifically Section 2.1 “for liquid wastes < 0.5% solids, the waste, after filtration through 0.6‐0.8 μm filter", is defined as the TCLP Extract. Would that be true for a VOC sample?
The method indicates that the percent solids be determined as described in Section 7.1 using the non‐ZHE filtration unit, and if the solids are less than 0.5%, section 7.1.2 directs the user to section 7.3 for volatile compounds.
Section 7.3.4 indicates that if the waste contains <0.5% solids, the liquid portion of the waste, after filtration, is defined as the TCLP extract. Although the method does not explicitly state this, it is presumed that liquid samples for volatiles would be filtered using the ZHE, and the filtrate would be collected for analysis.
However, it would be a more conservative, and therefore acceptable approach to analyze the liquid sample with less < 0.5% solids for VOCs without filtration. In this scenario, there is a possibility of getting a larger value without filtration that may cause a sample to be classified as hazardous when it is not technically hazardous (i.e., if it was carried through Method 1311 as written). This potential high bias is acceptable from a regulatory standpoint because the waste would be treated more carefully than if it was considered non‐hazardous.