WQ0029945_Correspondence_20201120

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. ❑ANIEL SMITH
Director
NORTH CAROLINA
Environmental Quality
November 20, 2020
DAVID M. MOHR — CHIEF OPERATIONS OFFICER
ONSLOW WATER AND SEWER AUTHORITY
228 GEORGETOWN ROAD
JACKSONVILLE, NORTH CAROLINA 28540
Subject: Application No. WQ0029945
Additional Information Request
Summerhouse Wastewater
Reclamation WWTP
High -Rate Infiltration System
Onslow County
Dear Mr. Mohr:
The Division has reviewed your letter dated November 13, 2020, addressing ONWASA's concerns
regarding the requested permit major modification. We appreciate your feedback on the operation of the
basin and the permit modification process. The Division acknowledges ONWASA's dissatisfaction with
the review process, and would like to extend the following information in response.
The proposed modification (i.e. increasing the hydraulic loading rate in Basin #2) is an expansion
and a major modification pursuant to G.S. 143-215.31)(d), therefore this permit shall be regulated under
15A NCAC 02T .0700. There are several outstanding 15A NCAC 02T requirements, including design
criteria and setbacks to infiltration sites, which must be addressed before a modified permit can be issued
[15A NCAC 02T .0705(y); 02T .0706(a)].
As previously communicated, there are other options available within the 15A NCAC 02T
regulations which do provide certain mechanisms to allow variations from both 15A NCAC 02T .0705(y)
and 02T .0706(a) requirements.
Setback waivers can be obtained from property owners within 100 feet of the basin pursuant to 15A
NCAC 02T .0706(e), to address the requirement of the 100-foot setback to habitable residences and allow
for reduced setbacks to the basin. Similarly, setbacks to surface waters, groundwater lowering ditches, and
subsurface groundwater lowering drainage systems shall be reduced to 50 feet, if it can be demonstrated
that the treatment units are able to meet effluent limits of 4 mg/L of total nitrogen and 2 mg/L of total
phosphorus as per 15A NCAC 02T .0706(c). Demonstration that these limits can be attained shall be
required from the Permittee to satisfy 15A NCAC 02T .0706(c) and 15A NCAC 02T .0105(n)(1).
Additionally, since the subsurface groundwater lowering drainage system cannot be inside the
compliance boundary as defined by 15A NCAC 02L .0107, ONWASA may request, and the Division will
grant, that the compliance boundary be established closer to the waste disposal area, provided that the
groundwater standards can be met at the newly established compliance boundary [15A NCAC 02T
.0105(h)]. Demonstration that these standards can be met at the compliance boundary shall also serve to
fulfill 15A NCAC 02T .0705(y) and 02T .0105(n).
,� North Carolina Department of Environmental Quality I Division of Water Resources
4��PEQ512 North Salisbury Street 1 1617 Mail Service Center I Raleigh, North Carolina 27699-1617
oepvmen�er e,.i�me„r.i mwe� r 919,707.9000

Mr. David M. Mohr
November 20, 2020
Page 2 of 2
As previously stated, the process for reviewing a permit application is iterative and involves
multiple staff members. Regardless of the date these complications were noted, they still must be addressed
before the permit can be modified. The Division is available for further consultation regarding the available
mechanisms to satisfy the problematic setback and design criteria.
If you have any questions, or would like to schedule a conference call with the Division, please do not
hesitate to contact me at [phone] or poonam.girikncdenr.gov. Thank you for your cooperation.
Sincerely,
Poonam A. Gill, Hydrogeologist
Division of Water Resources
cc: Wilmington Regional Office, Water Quality Regional Operations Section (Electronic Copy)
Miles Galloway, PE —The Wooten Company (Electronic Copy)
Permit Application File WQ0029945