NC0056731_Response to NOV-2023-LV-0632_20231017

October 09, 2023
Ms. Vanessa E. Manuel, Assistant Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
Division of Water Resources, NCDEQ
Subject: Notice of Violation and Assessment of Civil Penalty
Tracking Number: NOV-2023-LV-0632
Permit No. NCO056731
Grande Oak Subdivision WWTP
Durham County
Ms. Manuel,
The Chesson Group appreciate the opportunity to respond to this Notice of Violation issued September 14, 2023; received
on September 30, 2023, regarding the fecal coliform limit violations for the July monitoring period.
The Fecal coliform values of 600 Colonies /100ml, reported through the July monitoring period, as well the Monthly
geometric mean with a value of 534.3 Coliform colonies /100ml, does not represent the actual performance of the facility,
and have started a deeper investigation to determine the cause of the increase. As can be seen on the following charts
tracking back to March 2022, the different parameters have maintained a good performance without significative changes:
CI mg/1 Temp'C
2.5
15
1 --
0.5
otiti ryotiti �titi ryotiti �ti1 ryotil ryotiti votiti 1�~~ tip~~ oti� oti� ryoti� �ti� ryoti� ryoti� oti�
fG mg/1
F. coli
600
500
600
300
200
100
0
ti\ 4�\ �1
30
25
20
15
10 -
'YO.y'L ^YO.y^w .ti'L ryOtiry 'Lpy'L �oy'y ti0�~ ti0~~ 'i0.1'L ryoyti 'LO.I'j O.y'�a 'LO.ti'4 'LO.ti'9 'LO.1^a 'LO.1'j 013
Temp °C
7.5
6.5
5.5
5 --
4.5
tiry SP' '6 '3 .A3 cc, p
,��• a\' y\• 0\_ .��• Tti_ A�. ,ti0'�. ,ti`y�. ,5,�},. y�• ,�1• ,5�_ a�_ q\. ��_ ,`v
—p—E coli ADO
As part of the investigation, it has been proved that the treatment process has not been modified, all the field and compliance
parameters have been performing properly with no incidents, with the single exception of the fecal coliform. For that reason,
the Chlorine has been increased to help the system reduce the bacteria presence on the effluent.
The investigation and monitoring for the system has been increased to detect if an external factor is causing the fecal
exceedance since the system is being treated with disinfectant to eliminate any possible traces of bacteria. It is always our
goal to remain in compliance with regulations set forth by the Division of Water Resources. It is our request that our
cooperation and action in these matters be taken into account by the Division when proceeding with enforcement.

Sincerely,
Daniel Sears, on behalf of
The Chesson Group
CC:
Andrew White, Regional Manager, Envirolink, Inc.
Daniel Sears, Compliance Manager
Anthony Branch, Grande Oak WWTP ORC