NC0020656_Potential Toxins_20080104

&iI9 of Cauriofnirg
OFFICE OF THE TREATMENT PLANTS DIRECTOR
January 4, 2008
Cindy A. Moore
Supervisor, Aquatic Toxicology Unit
NC Division of Water Quality
1621 Mail Service Center
Raleigh, NC 27699-1621
DENR-FRO
JAN U 8 2008
DWQ
AO -America City
1
1956 2 3 1967
Re: Permit # NC0020656, Leith Creek WWTP, Scotland County
Documentation to Eliminate Copper as Potential Toxins To Our Toxicity Analysis
Dear Ms. Moore:
We are submitting ourDaily/Quarterly Toxicity Results Summary for your review from our
Leith Creek Waste Water Treatment Plant Laboratory and our Commercial Laboratory. We think
this documentation will eliminatecopper as. the source for Toxicity failure for November and
December 2006.
In this surnmary copper results are available for November 2006.butarenot available for,
December 2006. The reason -for this was that our staff had collected -several additional samples
and failed to collect the routine monthly samples. We initiated new sampling procedures to help
prevent this error from occurring in the future. We did however conduct 2 additional metal
analyses for the month of January along with our required monthly analysis and reported the
average of all three samples.
Please note in the Daily/Quarterly Toxicity Results Summary attachment it does include
Copper results for the months of February 2007 to November 2007.
As we discussed prior to you receiving our letter dated April 3, 2007 accepting Option #3 (TIE)
Toxicity Identification Evaluation, it was expressed to you that I thought the problem was the
Ammonia Nitrogen level during the Toxicity Testing period of November & December 2006.
During this time period aerator basin #1 on our extended aeration plant was out of service.. The
basin was out of service due to the failure of two mechanical aerators. We believed that the
influent flow to the plants were divided appropriately to acquire adequate treatment to maintain
compliance. After the results of our November 2006 Toxicity were received, we began diverting
more influent flow to the oxidation ditch side to reduce the levels of Ammonia Nitrogen in the
effluent. Before we could achieve the appropriate flows for each plant we had also failed our
December 2006 Toxicity Test. -
Per Daily/Quarterly Toxicity_ Results Summary as of Dec61146r.17, 2.006, Ammonia Nitrogen
levels had returned to normal. As you can see from results for Toxicity testing conducted on
January 2007,-February 2007, May 2007, August 2007 and November 2007 we were back in
compliance for toxicity. Based on these findings we feel as though Copper levels,did not cause
603 LAUCHWOOD DRIVE • P.O. BOX 249 0 LAURINBURG, N.C. 2R353 ® PHONE: [phone] FAX: [phone]

us to fail the toxicity test, we associate the failure to high levels of Ammonia Nitrogen, because
the copper results were consistent.
If you have any questions concerning this matter please contact us.
Sincerely,
Robert A. Ellis
Treatment Plants Director
Cc: Craig Honeycutt, City Manager
Ricky Odom, Chief Operator.
Belinda Henson, Fayetteville Regional Office
bra. R ctc,i.
Attachment

Plant Analysis In Comparision To Tox Results
Daily/Quarterly Toxicity Results Summary
Nov-06 Dec-06 Jan-07 Feb-07 May-07 Aug-07 Nov-07 Copper Mg/I Zinc Mg/I Total N Total Phosp. Toxicity.
NH3 Mg/I NH3 Mg/I NH3 Mg/I NH3 Mg/I NH3 Mg/I NH3 Mg/I NH3 Mg/1 Nov-06 0.027 0.076 23.6 4.07 • F
1 3.18 <.10 0.37 <.10 <.10 0.67 Dec-06 No Sample Collected - Operator Error F
2 4.12 <.10 <.10 <.10 (Additional Metals) Copper Mg/I Zinc Mg/I Sulfide Nickel
3 4.38 <.10 <.10 Jan 8-9 2007 0.010 0.037 <0.1 <0.010
4 3.78 <."10 <.10 0.44 Jan 11-12 2007 0.012 0.04 <0.1 <0.010
5 7.50 1.68 0.11 <.10 <.10 Copper Mg/I Zinc Mg/I Total N Total Phosp.
6 8.59 1.41 <.10 <.10 <.10 <.10 Routine Jan 9, 2007 0.014 _ 0.036 7.96 1.54 P
7 2.95 0.89 <.10 <.10 <.10 <.10 <.10 Copper Mg/1 Zinc Mg/I Total N Total Phosp. Sulfide Nickel
8 1.19 <.10 <.10 <.10 <.10 <.10 Jan 2007 DMR results 0.012 0.038 7.96 1.54 <0.1 <0.010 P
9 0.39 <.10 <.10 ' <.10 Feb-07 0.01 0.038 8.01 1.21 P
10 0.82 <.10 <.10 May-07 0.006 0.05 2.53 1.51 P
11 0.65 <.10 <.10 <2.0 Aug-07 0.017 0.075 22.3. 3.68 P
12 <.10 1.83 <.10 0.13 <2.0 Nov-07 0.011 0.069 23.4 2.95 P
13 0.32 2.29 <.10 <.10 0.14. 7:8
14 0.47 2.57 <.10 <.10 0.11 6.4
15 0.45 0.12 <.10 <.10 <.10 2.4.
16 0.79 1.07 <.10 <.10
17 <.10 1.25 <.10
18 <.10 <.10 <.10 2.4
19 0.68 0.23 <.10 <.10 2.4
20 <.10 0.38 0.35 <.10 0.11 <2.0 _
21 <.10 0.8 <.10 <.10 <,10 0.1 •
22 <.10 0.34 <.10 <.10
23 0.75 <.10 <.10
24 <.10 <.10
25 <.10 1.00 <2.0
26 0.18 <.10 1.40 <.10 2.3
27 0.11 <.10 0.68 <.10 <2.0
28 0.15 <.10 <.10 0.23 <.10 <.10 <2.0
29 1.90 0.27 <.10 <.10 <2.0
30 2.97 <.10 <.10 <.10
31 <.10 <.10
Plant Analysis In Comparision To Tox Results