NC0035708_Toxicity Considerations_20091231

Lopez, Dale
From: Lopez, Dale
Sent: Thursday, December 31, 2009 10:18 AM
To: Scherer, Janna
Cc: [e-mail]; Moore, Cindy; Henson, Belinda; Rawls, Paul; Brantley, Mark;
Hollenkamp, Carol; Folley, Dana; Ferrell, Lance; Lopez, Dale
Subject: Suggestions for TIE, possibly for future consideration
Hi Janna,
This letter is to summarize the suggestions from our conversation yesterday. Shortly before I spoke with you, I
consulted with Cindy Moore about what your facility might prepare for in case you have a WET "Fail" in the future and
at the beginning of a quarter of routine sampling for WET (as according to your NPDES permit). I agree with Cindy's
insightful suggestions: 1) as a precautionary measure, during each of the routine WET composite sampling events,
retain extra sample of the 24-hour composite that could later be used for analyses (with the preservatives added) that
may help in the TIE/TRE, and 2) prepare to sample the collection system lines that flow from the SIUs (ClUs), or any
other line that may be in question; use a modified WET 6-cup Pass/Fail test, (that may be more economical to perform --
- check with your commercial lab for pricing).
In addition, it would be a good idea for you to begin considering your calculations for the dilutions that you
would ask your commercial lab to run; use the %IWC and the dilutions through the POTW in order to back calculate to
the contributing dilution that the CIU would make to your Effluent 001 and then to the receiving stream --- %IWC. This
dilution method would not take into consideration the removal rates of toxicants by the POTW's units, but the dilution
calculation and modified WET would help you target the collection system line(s) from which the toxicant(s) are possibly
coming to your facility.
Please phone Cindy about her suggestions for Moore County Regional WWTP concerning the Cu/Zn policy so
that your actions are complete, on target, and with all necessary documentation.
Congratulations to Brant, to you, and to the Moore WWTP staff concerning the "Pass" WET conditions that
occurred for each of the triple split during the week of December 14th. You have satisfied the December quarter of the
permit, and the next required WET sampling event is due in March 2010.
Please keep me informed by email concerning your proactive approach to solving aquatic toxicity at Moore
County.
Thanks,
Dale
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