NC0021474_CORRESPONDENCE_19910912

NPDES DOCUMENT SCANNING COVER SHEET
NPDES Permit: NC0021474
Mebane WWTP
Document Type: Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Engineering Alternatives Analysis
201 Facilities Plan
Instream Assessment (67B)
ones oii&&rice ire . insiream samlilih
Permit History Date Range:
Document Date: e ternber 12 1991
This dooiamerit is printed on reuse paper-more nay
content on the reverse Bide

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September 12, 1991
MEMORANDUM
TO: Dale Overcash
Permits and Engineering
FROM: Setsy Johnson-r6
Technical Support�ch
THROUGH: Mike Scoville 06
Ruth Swanek i Z%
SUBJECT: Town of Mebane instream titoriitoring stations.
NPDES No. NC0021474
Alamance County
Mebane has requested changes in their monitoring 1QG+titions for safety reasons. The third
station, Back Creek at HWY 54 should be dropped. The second station, Back Creek at
SR 1936, should be replaced with Back Creek at SR 1940. This will result in the town
monitoring at two sites on SR 1940, one at Moadams Creek and one at Back Creek.
If you have any questions regarding these changes, please let me know.
cc: Central Files
Winston-Salem Regional Office

4UGrkqI 3 v 199j
Department of Environe of ment,rth Health, alinand Natural Resources
`JY, `ART BRA,
P n�H
Division of Environmental Management
512 North Salisbury Street•Raleigh,North Carolina 27611
James G. Martin, Governor George T. Everett,Ph.D.
William W. Cobey,Jr., Secretary Director
August 27, 1991
Mr. Robert Wilson, City Manager
City of Mebane
106 E. Washington Street
Mebane, NC 27302
Subject: NPDES Permit Application
NPDES Permit No. NCO021474
City of Mebane Wastewater Treatment Plant
Alamance County
Dear Mr. Wilson:
Reference is made to your letter of July 2, 1991 containing comments on the draft NPDES permit
NCO021474 for the City of Mebane. The Division of Environmental Management (DEM) has
reviewed the comments in this letter. The items are addressed in the following :
(1) (Choice#1) Metals limits are based on an allowable daily maximum to protect for the
chronic no-effect level at 7Q10 flow conditions. Monitoring is done at a weekly frequency.
Limits are listed below:
daily maximum CD �Fe
Cyanide (µg/1) 2 .0 S 0 C� Q\b�\
Cadmium (µg/1) .0 't.o
Chromium (µg/1) 2 0. S'0, 0
Nickel (µg/l) .0 gg 0
Lead (µg/l) 3 .0 as. 0
Mercury (µg/1) 0.048 0. 01l
(Choice#2) The City of Mebane may choose to have a higher daily maximum
level based on acute toxicity values with a weekly average limit to protect from chronic
toxicity effects. Monitoring is done Monday through Friday, with compliance based on the
average of the daily values (values which are below the detection level average in as zero).
HOWEVER, if Mondays sample is in compliance with the weeklyaverage verage limit, then no
additional samples need to be analyzed for the week. Limits are listed below:
weekly average daily maximum
Cyanide (µg/l) 5.0 20.0
Cadmium (µg/l) 2.0 5.0
Chromium (µg/1) 50.0 200.0
Nickel (µg/l) 88.0 352.0
Lead (µg/l) 25.0 34.0
Mercury (µg/I) 0.012 0.048
Pollution Prevention Pays
P.O.Box 27687.Raleigh,North Carolina 27611-7687 Telephone [phone]
An Equal Opportunity Affirmative Action Employer

i
The City has an option to choose either of the above metals limits and monitoring
frequencies, however, the monitoring frequency must be consistent for the life of the
permit.
(2) The mercury limit is 0.012 µg/l, the state water quality standard, as the City discharges to a
zero 7Q10 stream. Compliance is based on demonstrating an effluent level of "less than
detection" using the most sensitive approved analytical method. At present detection
methods are greater than 0.012 µg/1, but these levels could change in the future. In the
meantime, the City must achieve mercury sampling results of less than detection. The City
may choose to have weekly average and daily maximum limits as stated previously, but
both values are "less than detection" limits.
(3) The cadmium limit of 2.0 µg/1 must be met as the stream has a 7Q 10 of zero cfs. The
cadmium limit may be revised to a weekly average, daily maximum as stated previously.
(4) The suggested wording for the pretreatment program will not be added to the permit. The
Division is willing to discuss the pretreatment program with the City and work to achieve a
program which satisfies State and Federal pretreatment program requirements.
(5) Three downstream sampling sites were chosen due to the dominance of the City of Mebane
effluent on the stream flow. This monitoring is required during summer months only. If
the City feels the sites are unsafe, the City may propose alternate sites that are in close
proximity to the permitted sites or set up safety features to slow traffic when sampling.
Please respond by September 27, 1991, with any alternate sampling sites. If you have any
questions about potential sites, you may contact Ms. Betsy Johnson of the DEM Technical Support
Branch at 919/733-5083, ext. 507 or Mr. Eric Galamb of the DEM Winston-Salem Regional Office
at 919/761-2351. The City should also indicate the choice of metals sampling frequency at this
time. If you have any questions, you may contact Ms. Rosanne Barona at 919/733-5083.
Sincerely,
Steve W. Tedder, Chief
Water Quality Section
cc: Winston-Salem Regional Office
ca u ort Branch
Mr. Bob Teu mgs
Permit File

North Carolina Division of Environmental Management
Water Quality Section/Intensive Survey Group
August 2, 1991
MEMORANDUM
To: Ruth Swanek
Through: Jay Sauber1 u/-"��ypy�
From: Howard Bryant 4M 6
Subject: Long-term BOD Analysis for Mebane WWTP (100%)
County: Alamance
NPDES#NC0021274
Receiving Stream: Moadams Creek
Sub-basin: 30602
PAY BOD I -N TKN-N NOX-N TN-N
0 0.73 2.3 10.00 12.0
5 5.24 0.81 2.6 10.00 13.0
10 10.08 0.09 1 .4 11 .00 12.0
15 12.67 0.01 1 .5 12.00 14.0
20 15.06 0.02 1 .5 12.00 14.0
25 16.81
30 18.53 0.02 1 .9 12.00 14.0
35 20.32
40 21 .79
50 23.86
60 25.74
70 27.17
80 28.02
90 28.70
100 29.27
1 1 0 29.74
Date Collected: March 21, 1991 Collected by: Galamb Test evaluation: excellent
0 8 0 0-0 8 0 0 pH:7.7 Seeded: seeded
cc: Central Files
Regional Water Quality Supervisor

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July 22, 1991
MEMORANDUM
TO: Dale Overcash
Permits and Engineering
FROM: Betsy_JShnson-&
Technical Support
THROUGH: Mike Scoville ft5
Ruth Swanek
SUBJECT: City of Mebane WWTP draft permit.
NPDES No. NCO021474
Alamance County
The following comments are in response to Mebane's objections to
its draft permit:
1 . Metals limits are based on an allowable daily maximum to protect
for the chronic no-effect level at 7Q10 flow conditions. A facility
may substitute a higher daily maximum level based on acute values
if it monitors daily (Mon-Fri). A weekly average limit must also be
met to protect from chronic effects. Compliance is based on the
average of the daily values (values BDL average in as zero). If
Monday's sample is in compliance with the weekly average, then no
additional samples for the week need be analyzed. The facility
must choose its monitoring frequency and stick to it for the life of
the permit.
Mebane's limits would be:
weekly daily
average maximum
Cyanide (ug/1) 5 20
Cadmium (ug/1) 2 5
Chromium (ug/I) 50 200
Nickel (ug/1) 88 352
Lead (ug/1) 25 34
*rtu.y (w311) lot?- 100

2. The mercury limit is 0.012 ug/I, which is the state standard.
Compliance is based on demonstrating an effluent level of "less than
detection" using the most sensitive approved analytical method.
Though current detection methods are greater than 0.012 ug/I, they
may change in the future. In the meantime, Mebane must achieve
less than detection.
3. The Cadmium limit is 2.0 ug/I which is the state standard. Since
the 7Q10=0 cfs, the standard must be met in the effluent. The
Cadmium limit is an existing limit and must be retained. See
Comment number 1 . for further information.
4. The wording in the Pretreatment Program Implementation should
remain as stated in the permit. The "mutually agreed" comment is
unacceptable. The Division is willing to discuss the pretreatment
program and work with Mebane to achieve a program which satisfies
state and Federal pretreatment program requirements.
5. Three downstream sampling points are recommended for Mebane
due to the dominance of Mebane's effluent on stream flow. The sites
on Back Creek will allow DEM to determine the extent of Mebane's
influence. The monitoring for Back Creek is required during summer
months only. If the sites are unsafe, the City may propose alternate
sites that are in close proximity to the permitted sites or set up
safety features to slow traffic when sampling.
cc: Central Files
Winston-Salem Regional Office

City of Mebane
_ Chartered in 1881 r" ��}( 4 f.
d0(- 10 i991 106 E.Washington Street
Mebane,N.C. 27302 d
Jc '? '.: i [phone]
�! July 2, 1991
Dr. George T. Everett, Director
Division of Environmental Management
Post Office Box 27687
Raleigh, North Carolina 27611-7687 JUL 1 1 1991
Re: City of Mebane NPDES permit, NC 0021474
TECHNICAL 5 ,'sWtf BRANCH
Dear Dr. Everett:
r
t
After review of our proposed permit, our wastewater treatment director and''
consulting engineer have several concerns which we feel need to be addressed at
this time.
0 1. The metal limitations as proposed are on a daily maximum. We request that
they be changed to a monthly average. All other parameters are on an
u ��y average basis and we feel that an average for metals is also appropriate.
Wu�G P 2. The mercury limit has been reduced to 0.012 ug/l. As stated in Part II,
Section D, number 4 of the permit, "If no approved methods are determined
capable of achieving minimum detection and reporting levels below permit
discharge requirements, then the most sensitive (method with the lowest
possible detection and reporting level) approved method must be used. "
This limit is set at present by the analytical procedures approved by the
USEPA for Mercury, which are manual and automated cold vapor methods
�Q �h (Method 245. 1 and 245.2) . Both methods explicitly set the lower limit of
detection at 0.0002 mg/l. For practical purposes, this is the lowest level
of Mercury which can be reported for regulatory purposes. To the best of
PN� C• our knowledge, EPA had not approved any procedure for concentrating Mercury
in samples to enable measuring levels to the proposed limit. We therefore
-u^ R believe that the inclusion of limits which cannot be accurately measured is
v �mot appropriate, and we request that the limit be raised to 0.30 ug/1
CC),4 �
( L a because the discharge is not on a 30 Q2 %stream.
ry 3. The Cadmium limit is proposed at 2.0 ug/l. We request that this level be
.r raised to 3.0 ug/l because the discharge from this plant is to a stream
C,M' with a 30Q2 flow greater than zero.
r'x Oa 4. In part III, Section B, number 2, Pretreatment Program Implementation, a
change in wording is requested. We suggest that it read: The pern-ittee
shall modify and implement the monitoring program based on mutually agreed
comments received by the Division within 180 days of the effective date of
this permit.
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Mr. George T. Everett
Director, DEM Re: City of Mebane NPDES permit
page 2 NC 0021474
July 2, 1991
1,vj5. Downstream sampling locations are proposed to be changed to three points,
SR 1940 at Moadams Creek, SR 1936 at Back Creek, and NC Highway 54 at Back
Creek. Our main concern over these locations is for safety of our
personnel. There is heavy traffic on Hwy 54 and the bridge over Back Creek
tdt on SR 1936 is narrow and makes pedestrian traffic rather unsafe. Suitable
parking for our vehicles near these sites is also a major concern. It also
J)d appears that the sampling of the Back Creek sites is not appropriated to us
as the Back Creek has considerably more flow as compared to our discharge.
C V 2�i We request that the Back Creek sites be eliminated from our sampling
r points.
o-�OZ
"''�� It is hoped that the requested changes can be made to our proposed permit to
make it a workable permit and one that we can confidently comply with.
If you have any questions, please call.
Sincerely,
CITY OF MEBANE
Robert Wilson, City Manager
/t
cc: Mike Hite, W.T.P. , Director
Darrell Russell, Alley, Williams, Carmen, & King, Inc.