Frequent Questions

Are the Land Disposal Restriction (LDR) treatment standards based on grab sampling or composite sampling?

Compliance with LDR treatment standards is based on grab sampling for D004-D011 wastewaters and for all nonwastewaters (§268.40(b)). In addition, compliance with treatment standards for underlying hazardous constituents is measured by an analysis of grab samples, unless otherwise noted in §268.48. A grab sample is a one-time sample taken from any part of the waste. Using grab sampling to measure compliance with the treatment standards ensures conformity with LDR program goals such that all of the hazardous waste to be land disposed is treated to minimize the threats to human health and the environment (62 FR 26041, 26047; May 12, 1997). EPA established treatment standards for prohibited wastes based on grab sampling because it makes treatment standards easier to enforce. In addition, grab samples normally reflect maximum process variability, and thus reasonably characterize the range of treatment system performance (54 FR 26594, 26605; June 23, 1989). By contrast, composite sampling, which is a combination of samples collected at various locations or times for a given waste, may result in only an average portion of the waste being treated (62 FR 26041, 26047; May 12, 1997). 

The May 12, 1997, Federal Register is available at the following URL:
 http://www.epa.gov/fedrgstr/EPA-WASTE/index.html

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