NC0037508_Speculative Limits_20061030

v.
Michael F. Easley, Governor
State of North Carolina
William G. Ross, Jr., Secretary
Department of Environment and Natural Resources
Alan W. Klimek, P.E., Director
Division of Water Quality
October 30, 2006
Mr. Brian Sexton, Project Manager
Hobbs, Upchurch and Associates
300 S.W. Broad Street
Southern Pines, North Carolina 28388
Subject: Speculative, Effluent Limits Request
Moore County Water Pollution Control Plant
NPDES Permit NCO037508
Moore County
Dear Mr. Sexton:
This letter is in response to your request for speculative effluent limits for 12.5 MGD for the Moore County
Water Pollution Control Plant. We have reviewed the request and provide the following response.
The Division had previously evaluated a speculative limits request for 10 and 15 MGD. A model was run at the
time and the results predicted that limits of 5 mg/1 of BOD and 1 mg/1 of ammonia as a summer limits would
protect water quality in the receiving stream. The model framework is still valid, thus the speculative limits for
12.5 MGD are the same as the limits we provided in 1999.
Based on the available information, tentative limits for the Moore County Water Pollution Control Plant at the
expanded flow of 12.5 MGD are as follows:
SPECULATIVE LIMITS -
Parameter
Monthly Average
Weekly Average
Daily: Maximum .._ .
Flow (MGD)
12.5
BOD, 5-day, 20'C (April 1 - October 31)
5.0 mg/L
7.5 mg/L
BOD, 5-day, 20°C (November 1 -March 31)
10.0 mg/L
15.0 mg/L
Total Suspended Solids
30.0 mg/L
45.0 mg/L
NH3 as N (April 1 — October 31)
1.0 mg/L
3.0 mg/L
NH3 as N (November 1 — March 31)
2.0 mg/L
1 6.0 mg/L
Dissolved Oxygen
Minimum 6.0 mg/L
PH
>6.0 and <9.0 standard units
Fecal Coliform (geometric mean)
200/100 ml
400/100 ml
Total Residual Chlorine
28 µg/L
Total Phosphorus
Total Nitrogen
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North Carolina Division of Water Quality 1617 Mail Service Center Raleigh, NC 27699-1617 Phone [phone] Customer Service
Internet: h2o.enr.state.nc.us 512 N. Salisbury St. Raleigh, NC 27604 FAX [phone]
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper

Ms. Brian Sexton
Moore County Speculative Limits
Page 2
Engineering Alternatives Analysis (EAA). Please note that the Division cannot guarantee that an NPDES permit
modification for expansion to 12.5 MGD will be issued with these speculative limits. Final decisions can only be
made after the Division receives and evaluates a formal permit application for the County's proposed discharge.
In accordance with the North Carolina General Statutes, the practicable wastewater treatment and disposal
alternative with the least adverse impact on the environment is required to be implemented. Therefore, as a
component of all NPDES permit applications for new or expanding flow, a detailed engineering alternatives
analysis (EAA) must be prepared. The EAA must justify requested flows, and provide an analysis of potential
wastewater treatment alternatives. Alternatives to a surface water discharge, such as spray/drip irrigation,
wastewater reuse, or inflow/infiltration reduction, are considered to be environmentally preferable. A copy of the
EAA requirements is attached to this letter. Permit applications for new or expanding flow will be returned
as incomplete if all EAA requirements are not adequately addressed. If you have any questions regarding
these requirements, please contact the DWQ NPDES Unit at 919-733-5083.
State Environmental Policy Act (SEPA) EA/EIS Requirements. A SEPA EA/EIS document must be prepared for
all projects that 1) need a permit; 2) use public money or affect public lands; and 3) might have a potential to
significantly impact the environment. For new wastewater discharges, significant impact is defined as a proposed
discharge of >500,000 gpd and producing an instream waste concentration of > 33% based on summer 7Q10 flow
conditions. For existing discharges, significant impact is defined as an expansion of > 500,000 gpd additional
flow. Since your existing facility is proposing an expansion of >500,000 gpd additional flow, you must
prepare a SEPA document that evaluates the potential for impacting the quality of the environment. The
NPDES Unit will not accept an NPDES permit application for the proposed expansion until the Division
has approved the SEPA document and sent a Finding of No Significant Impact (FONSI) to the State
Clearinghouse for review and comment. A SEPA Environmental Assessment (EA) should contain a clear
justification for the proposed project. If the SEPA EA demonstrates that the project may result in a significant
adverse effect on the quality of the environment, you must then prepare a SEPA EIS (Environmental Impact
Statement). Since your proposed expansion is subject to SEPA, the EAA requirements discussed above will
need to be folded into the SEPA document. The SEPA process will be delayed if all EAA requirements are
not adequately addressed. If you have any questions regarding SEPA EVEIS requirements, please contact the
DWQ Planning Branch at [phone], ext. 555.
I trust this response offers sufficient guidance for the County's proposed treatment plant expansion. If you have
any additional questions about these limits, feel free to contact Teresa Rodriguez at [phone] ext. 553.
incerely,
tii2lG tNrt� s t G�v�r'�7 DY
��� ViNZA�te
Gil Vinzani
EAST NPDES Unit Supervisor
cc: Central Files
Fayetteville Regional Office — Surface Water Protection
East NPDES Unit

� Hobbs, Upchurch & Associates, P.A.
Consulting Engineers
300 S.W. Broad Street • Southern Pines, NC 28388
August 10, 2006
Ms. Jackie Nowell, Environmental Specialist
NCDENR-Division of Water Quality, NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Re: Request for Speculative Effluent Limits at Aberdeen Creek, Moore County, NC
Moore County Water Pollution Control Plant
HUA No.: MO 0509.100
Dear Ms. Nowell:
Moore County Public Utilities is in the planning stages of upgrading the capacity of the existing
wastewater treatment facility. An Engineering Report (ER) is being prepared for submission to
NCDENR-Construction Grants & Loans for environmental/technical review and funding
consideration. Also, an Engineering Alternatives Analysis (FAA) is being performed to analyze the
viability of all options with regard to wastewater treatment needs and disposal alternatives as
required by the NPDES permit review process. The preliminary findings of the EAA is that the
preferred alternative for wastewater treatment and disposal is the expansion of the existing
wastewater treatment facility located along Aberdeen Creek in extreme southern Moore County.
According to recent population growth and flow projections, it is estimated that the exiting 6.7
MGD wastewater treatment facility should be upgraded to a 12.5 MGD wastewater treatment
facility to facilitate for the 20-year needs of the existing Moore County sewer service area, existing
flow commitments, and future sewer service areas. The methodology for obtaining these projected
flow rates is established by NCDENR Construction Grants & Loans and should be approved
during the technical review of the ER. On behalf of Moore County, we request that the NPDES
provide speculative effluent limits on Aberdeen Creek at the following levels: 10.0 MGD and 12.5
MGD.
The Moore County Water Pollution Control Plant is a regional facility, and currently receives
wastewater from the Towns of Aberdeen, Addor, Carthage, Pinehurst, Southern Pines, and
Taylortown, as well as Camp Mackall military reservation in Richmond/Hoke counties. It is
anticipated that the site of the existing wastewater treatment plant can accommodate the
construction of additional facilities for the increased discharge.
The Moore County Water Pollution Control Plant operates under NPDES Permit number
NC0037508, effective July 1, 2005 until July 31, 2009. Current treatment process consists of
activated sludge wastewater treatment including the following: pre -aeration, grit removal, primary
clarification, first -stage activated sludge, intermediate clarification, second -stage aeration, final
clarification, anaerobic sludge digestion, sludge drying beds, and post -aeration.
Southern Pines, NC • Telephone [phone] . Fax [phone] • email: [e-mail]
Myrtle Beach . Nags Head . Charlotte . Beaufort

Page 2 of 2
The wastewater treatment facility discharges to Aberdeen Creek, a Class C water in the Lumber
River Basin (see attached map). The current monthly average permit levels for BOD are 22.0(s)-
30.0(w) mg/l, TSS are 30.0 mg/l, and Ammonia are 2.1(s)-6.2(w) mg/l. The most recent permit also
includes a daily maximum Total Chlorine Residual of 28 Ag/L and a weekly average limit on Total
Mercury of 12ng/L.
If you have any questions about the scope of the proposed project, please contact me at 910-692-
5616.
Sincerely,
Enclosures
OCIATES, P.A.