EPA Reconsiders Alternate Testing Method For Determining NPDES Permit Compliance

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By Patrick Ambrosio

The Environmental Protection Agency is reconsidering a decision not to include an alternative analytical method for the measurement of oil and grease in a 2010 proposed rule to approve new test procedures for measuring pollutants under the Clean Water Act.

In a notice to be published in the Dec. 14 Federal Register, EPA said that it may revise its proposal to include ASTM D7575-10 as an alternative to EPA Method 1664A, the current method for measurement of oil and grease.

The September 2010 proposed rule would add new and revised EPA methods to its Part 136 test procedures, which are used to determine compliance with National Pollutant Discharge Elimination System (NPDES) permits or other Clean Water Act requirements (185 DEN A-5, 9/27/10).

EPA is seeking public comments on its reconsideration, the supporting data, and the resulting EPA analysis. The deadline for submitting comments is Feb. 13.

ASTM D7575-10 uses an extracting membrane that retains sample materials, which are then examined using infrared measurement to determine the level of oil and grease. The process was originally developed by Orono Spectral Solutions (OSS) and approved by ASTM International in January 2010, EPA said.

If ASTM D7575-10 is ultimately listed as a test method, it would provide additional flexibility to permit holders in measuring oil and grease without adding any burden, EPA said.

Analysis Shows Advantages

EPA said that it is reconsidering its decision because analysis showed that ASTM D7575-10 is an “acceptable-stand-alone method” for the measurement of oil and grease in wastewater.

The test produces “results that are generally very close” to those obtained using the current method, EPA said.

EPA also said that the alternative method has “substantial advantages” over the current method because it extracts samples without the use of a solvent, preventing solvent waste and analyst exposure to solvent. The alternative method also may result in reduced analysis time and lower analytical costs, according to the notice.

EPA Method 1664A, the current method, is a liquid extraction procedure that uses normal hexane (n-hexane) as a solvent.

EPA said that it was persuaded by public comments to reconsider its position on ASTM D7575-10. One comment urged the use of an alternative method for measuring oil and grease because n-hexane is toxic to humans and the environment, EPA said.

Some comments, including those submitted by ASTM and OSS, requested that EPA consider adding the testing method because it is solvent-free and provides reliable results compared to the current method.

Public comments on the notice of data availability can be submitted online under Docket ID No. EPA-HQ-2010-0192 at http://www.regulations.gov or e-mailed to OW-docket@epamail.epa.gov.


EPA's notice is available at http://op.bna.com/env.nsf/r?Open=smiy-8phs7t .