NC0024970_correspondence_19890615

ReC4
titiNp
IeCHNI c�`��9
� SCR �
State of North Carolina v�i �°''2
Department of Natural Resources and Community Development
Division of Environmental Management
512 North Salisbury Street • Raleigh, North Carolina 27611
James G. Martin, Governor
William W. Cobey, Jr., Secretary
June 15, 1989
George M. Caughman, P.E., Director
Domestic Wastewater Division
Bureau of Water Pollution Control
S.C. Dept. of Health and Environmental Control
2600 Bull Street
Columbia, SC 29201
Subject: CMUD McAlpine Creek WWTP
NC0024970
Mecklenburg County
Dear Mr. Caughman:
R. Paul Wilms
Director
I am writing in response to your letter of May 23 concerning
Charlotte's McAlpine Creek WWTP draft NPDES permit. In your let-
ter, you were concerned about the following issues:
(1) Limits Derived from the Instream Waste Concentration.
The metals limits were derived using a mass balance
technique which determines allowable loading based on the
standard for a particular metal, the plant design flow (40
mgd), the 7Q10 flow at the outfall (0.3 cfs), and upstream
data from ambient station 02146750 located just below the
confluence of McMullen and McAlpine Creeks.
The BOD, and ammonia limits were based on previous
modeling studies which assumed a CBOD:BOD5 ratio of 1.5.
Recent longterm BOD data indicate that the ratio is actually
near 4, and therefore the limits may not be stringent enough
to maintain the DO standard downstream. However, it is Divi-
sion procedure to assign a facility existing limits unless
dissolved oxygen problems associated with the current waste -
load allocation have been observed instream. The instream
data collected at NCSR 2964 indicate that DO violations have
occurred. However, the violations occurred when the facility
was out of compliance or under a Special Order of Consent and
P.O. Box 27687, Raleigh, North Carolina 27611-7687 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

are not indicative of the anticipated water quality when the
facility is in compliance. DEM will continue monitoring the
situation to determine whether additional management action
is necessary. The intensive survey of the entire Sugar Creek
Basin now underway by DEM was outlined to representatives of
your staff on May 1 of this year. This study should provide
considerable insight to this issue.
(2) Reopener Language Included in Permit
I have attached a copy of the reopener clauses specifi-
cally contained in the NPDES permit for your review.
Although neither reopener specifically mentions the ongoing
water quality studies, the Division has the regulatory
authority to open any permit if water quality problems are
documented under existing permit conditions.
(3) Total Residual Chlorine Limits
The Division cannot apply chlorine limits to Class C
waters since no water quality standard for chlorine exists at
this time in North Carolina. New standards scheduled for
adoption in October include a chlorine action level of 17
ug/1. If the new regulations are approved, total residual
chlorine limits will be required if it is determined that
effluent concentrations of this parameter are resulting in
instream toxicity as determined by whole -effluent toxicity
monitoring.
I hope this response is satisfactory. If you"have further
questions, please contact Trevor Clements or Arthur Mouberry of my
staff at [phone].
Attachment
CC:
Arthur Mouberry
Trevor Clements
Rex Gleason
Central Files
S
R. Paul Wilms

Part III
Continued
D. Construction
No construction of wastewater treatment facilities or additions thereto
shall be begun until Final Plans and Specifications have been submitted to
the Division of Environmental Management --and written approval and
Authorization to Construct has been issued.
E. Certified Operator
Pursuant to Chapter 90A of North Carolina General Statutes, the permittee
shall employ a certified wastewater treatment plant operator in responsible
charge of the wastewater treatment facilities. Such operator must hold a
certification of the grade equivalent to or greater than the classification
assigned to the wastewater treatment facilities.
F. Groundwater Monitoring
The permittee shall, upon written notice from the Director of the Division
of Environmental Management, conduct groundwater monitoring as may be
required to determine the compliance of this NPDES permitted facility with
the current groundwater standards.
G. Limitations Reopener
This permit shall be.modiffed or alternatively, revoked and reissued, to
comply with any applicable effluent guideline or water quality standard
issued or approved under Section 302(b)(2)(c), and (d), 304(b)(2), and
307(a)(2) of the Clean Water Act, if the effluent guideline or water
quality standard so issued or approved:
1. contains different conditions or is otherwise more stringent than
any effluent limitation in the permit; or
2. controls any pollutant not limited in the permit.
This permit as modified or reissued under this paragraph shall also contain
any other requirements in the Act then applicable.
H. Toxicity Reopener
This permit shall be modified, or revoked and reissued to incorporate
toxicity limitations and/or monitoring requirements in. the event toxicity
testing or other studies conducted on•the effluent or receiving stream
indicate that detrimental'effects may be expected in the receiving stream
as a result of this discharge.

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IV
345 COURTLAND STREET
ATLANTA. GEORGIA 90365
JUN 9 i989
REF: 4WM-FP
Steve Tedder, Chief
Water Quality Section
Division of Environmental Management
NC Dept. of Natural Resources
and Community Development
P. 0. Box 27687
Raleigh, North Carolina 27611-7687
RE: Charlotte-Mecklenburg/McAlpine Creek WIP
NPDES Permit No. NC0024970
Dear Mr. Tedder:
JUN 16 1989
WATER QUALITY
SECT IO N
We have reviewed the draft permit for the Charlotte-Mecklenburg/McAlpine
Creek WWTP and concur with the conditions. While we have no objection to the
issuance of this permit we do have sane carnlents.
We understand that there have been standards violations in McAlpine Creek and
that an intensive study has been made on McAlpine Creek and that studies are
in progress on Sugar Creek. When modeling work is completed based on these
studies, tighter limits may be required for this facility.
Also, our Water Quality Standards and Monitoring Section has indicated that
the proposed ammonia limits could result in stream concentrations greater
than EPA criteria._=_I -th a is a chronic toxicity r it h nt-mith reopener
clause/th-tesforganism may not be appropriate to measure ammonia toil 'ty.
W- are -still waiting on the report on the ammonia toxicity evaluation for e
reensboro/North Buffalo Creek WWTP. Please let me know when I will ve
a copy of this report.
J
ohn T. Marlar, Chief
Facilities Performance Branch
Water Management Division