NC0037508_NPDES Permit_20061030

Mr. Brian Sexton, Project Manager
Hobbs, Upchurch and Associates
300 S.W. Broad Street
Southern Pines, North Carolina 28388
Dear Mr. Sexton:
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
D NA FH
OLT 3 12006
DINO
Subject: Speculative Effluent Limits Request
Moore County Water Pollution Control Plant
'NPDES Permit NC0037508
Moore County
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/I 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_ foxthe_ Moore_ County_Water_ Pollution Contr-ol_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
6.0 mg/L
Dissolved Oxygen
Minimum 6.0 mg/L
PH
>6.0 and <9.0standard units
Fecal Coliform (geometric mean)
200/100 ml
400/100 ml
Total Residual Chlorine
28 µg/L
Total Phosphorus
Total Nitrogen
NorthCarolina
Naturally
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 EA/EIS 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.
Gil Vinzani
EAST NPDES Unit Supervisor
cc_ : - Central Files -
t�Fayetteville,Regional Offices Surface WaterProtection
East NPDES Unit