NC0036277_Composite Collection Time Correstions_20170607

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CHARLOTTE
W6TER
May 25, 2017
Mr. Wes Bell
NCDEQ — Division of Water Resources
610 E. Center Avenue, Suite 301
Mooresville, NC 28115
RECEIVED/NCDEWWR
JUN 0 7 2017
Water Quality
Permitting Section
Subject: Composite Collection Time Corrections for McDowell Creek WWTP (NC0036277)
Mr. Bell:
This letter is to address several inaccuracies that Charlotte Water (CLTWater) recently discovered on
past eDMR submissions. These were a result of keying 'sample collection time' instead of 'sample end
time' into our data tracking software. On April 4, 2017, Shannon Sypolt (of CLTWater) contacted you to
discuss this matter, and was advised to respond with a formal written letter. Contained in this letter are
the known inaccuracies along with corrected information. CLTWater will also provide an explanation for
how the errors occurred, as well as steps that have been taken to mitigate these types of reporting
inaccuracies in the future.
Background
All of the inaccuracies are for the McDowell Creek Wastewater Treatment Plant (NC0036277), and are
centered on the 'Composite Sample Time'that is reported for both influent and effluent samples at the
facility. None of these corrections will result in significant changes to the overall 24-hour composite
samples used to judge compliance, and thus all of the resulting data is still legally valid and defensible.
CLTWater, in the interest of accuracy and full disclosure, is bringing this information to the attention of the
Division of Water Resources.
The inaccuracies in 'Composite Sample Time' were initially identified by Mr. Joseph Lockler (WWTP
ORC), during -normal data review processes. Sample times are manually entered into data management
software by the operations staff at the McDowell Creek WWTP. On occasion, staff have inadvertently
keyed incorrect times from the associated Chain of Custody and entered it into the tracking system.
Specifically, staff have occasionally keyed the 'sample collection time' instead of the required 'sample end
time' into the tracking software. Generally, there are several minutes difference between these two
values. This data is then transferred into the eDMR portal and reported to the Division of Water
Resources.
Charlotte Water 4222 YWestniont Dr, ClAatlotte, NC 28217 charlottewater.org
4�2 Operated by the City of Charlotte

Inaccuracies
Below is a table that identifies all of the dates, incorrect `Composite Sample Time' entries, actual
`Composite Sample Time' data, the resulting differences, and the actual total composite time.
McDowell Creek WWTP eDMR `Composite Sample Time' Corrections
Date
'Composite Sample
Time' Reported on
eDMR 2400 clock
Actual `Composite
Sample Time' Data
2400 clock
Overall Time
Difference
Minutes
Total
Composite
Time
--
Influent
Effluent
Influent
Effluent
--
05/23/2016 i
0600
0559
1
23:59
05/23/2016
0621
0620
1
24:00
08/19/2016
0841
0847
6
23:59
09/21/2016
Ofi 10
0604
6
24:04
09/21/2016
0630
0626
4
24:08
09/23/2016
0601
0602
1
24:01
09/23/2016
0620
0616
4
23:56
09/28/2016
0600
0603
3
23:55
09/28/2016
0620
0628
8
24:03
09/29/2016
0603
0600
3
23:57
09/29/2016
0628
0620
8
23:52
10/12/2016
0559
0558
1
23:58
11/01/2016
0606
0557
9
23:58
11101/201(
0625
0617
8
23:58
11/17/2016
0621
0620
1
23:59
12/08/2016
0819
0818
1
24:05
01/09/2017
0656
0649
7
23:59
01/23/2017
0842
0843
1
24:01
Preventative Action
In order to prevent this type of reporting inaccuracy in the future, McDowell Creek WWTP has made two
key changes:
1. The Chain of Custody form used during sample collection now has critical cells highlighted. This
should help reduce situations where operators accidentally transfer data from the wrong column.
2. A second operator will now be reviewing the times that are manually entered into our data
tracking software. This will be done on a daily basis.
We believe that these two simple steps will help to eliminate this type of problem in the future.
Charlotte Water 4222 Westmont Dr, Charlotte, NC 28217 tel [phone] fax [phone] charlottewater.org
Operated by the City of Charlotte

Summary
As shown above, the discrepancies resulting from inadvertently reporting 'sample collection time' instead
of'sample end time' data is minimal. The integrity of the data derived from these samples is unaffected,
and the primary purpose of documenting these discrepancies is to demonstrate CLTWater's commitment
to complete and accurate reporting.
Charlotte Water appreciates the open and honest communication that is shared between our offices. If
you have any questions or require further information concerning this letter please feel free to contact
Shannon Sypolt, Water Quality Program Administrator, at [phone] or me at [phone].
Respectfully, (�
l
�Maqa4linee A. Jarrell P.E.
0f erations Chief, Environmental Management Division
Charlotte Water
CC:
Derek Denard, NCDEQ — DWR
S. Sypolt, CLTWater
Charlotte Water 4222 Westmont Dr, Charlotte, NC 28217 tel [phone] fax [phone] charlottewater.org
c Operated by the City of Charlotte