NC0000272_Email_20120222

Cranford, Chuck
From: Francies, Gary
Sent: Wednesday, February 22, 2012 9:11 AM
To: Cranford, Chuck
Subject: color issue at Evergreen
Chuck
Below is what is going in inspection report. If you want we can discuss how we got here
Color— NCASI Method 71.01
Color— NCASI Method 253
Comment: The laboratory was not reporting all of the data for the effluent color samples. The North Carolina
Administrative Code, 15A NCAC 02B .0506 (3) (J) states: "The results of all tests on the characteristics of the
effluent, including but not limited to NPDES Permit Monitoring Requirements, shall be reported on monthly report
forms." The samples were analyzed in duplicate and averaged during each of two shifts and the lowest obtained
averaged value was reported. The laboratory did this believing that the differences in the results were due to
turbidity interference caused by colloidal solids. The colloidal solids are sometimes visible in the first analyses and
then disappear during refrigeration prior to the second analysis. At other times the colloidal solids are not visible
until the sample is stored in the refrigerator prior to the second analysis. The method states that "even a slight
turbidity causes the measured color to be noticeably higher than the true color." For most samples, the method
required filtration with a 0.8 micron filter is sufficient to remove turbidity. After consulting with both EPA Region IV
and National Council Air Stream Improvement (NCASI), it appears the colloidal solids may be an interference in
obtaining the true color concentration. The laboratory is currently compiling data to demonstrate the effect of the
colloidal solids and turbidity on the color concentration of the sample. A meeting will be scheduled in March 2012
to evaluate the data and discuss possible method modifications. To ensure Clean Water Act compliance the
laboratory may need to request approval for any proposed method modification from EPA Region IV. Until this
issue is resolved, the laboratory will average all effluent color results for reporting on the Discharge Monitoring
Report in order to comply with the above cited Rule.
Thanks
Gary
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Gary [e-mail]
North Carolina Dept. of Environment and Natural Resources
Asheville Regional Office
Division of Water Quality- Laboratory Certification
2090 U.S. 70 Highway
Swannanoa, NC 28778
Tel: [phone]
Fax: [phone]
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