NC0025071_Staff Comments_19900502

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DIVISION OF ENVIRONMENTAL MANAGEMENT
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MEMORANDUM
TO: Dale Overcash
FROM:
Juan Mangle
THROUGH: Carla Sanderson,
Trevor Clements �(i
SUBJECT: Response to Eden- ebane
Bridge comments on draft permit.
The City of Eden has reviewed the draft NPDES permit and has a
number of questions regarding the permit limits vs. the SOC limits.
The major question repeatedly asked is when SOC limits apply and when
current permit limits apply. We have asked the region to clarify the
difference, i.e., that the SOC supersedes the current permit for the
parameters listed in the SOC only. Additionally, this draft permit
renewal for 7 MGD, is simply an interim permit until Eden applies for
modification to 13.5 MGD. In response to their specific questions:
1. Color:
During the SOC there will be no color limit but effluent
monitoring is required (daily, 24 hr composite). If the SOC expires
and the plant remains at 7 MGD, an instantaneous maximum limit of 540
ADMI applies. After expansion to 13.5 MGD, an instantaneous maximum
limit of 300 ADMI must be met and effluent monitoring will continue
to be required on a daily (24 hr composite) basis. Instream
monitoring at three sites, two upstream and one downstream (grab
samples, summer=3/week, winter=l/week) is also required. At the
downstream site a transect shall be sampled, 1/4, 1/2, and 3/4 of
distance between banks (grab simples at each -- do not mix the
transect samples).
The draft permit addressed the frequencies and type of instream
monitoring in the comment section but was inconsistent with the
permit page. Effluent monitoring should have been included.
2. Ammonia:
During the SOC and post-SOC periods, weekly monitoring for
ammonia is required.
3. Fecal Coliform:
During the SOC, the fecal limit is 1000 colonies/100 ml.
Post-SOC the limit will be 200 colonies/100 ml for all wasteflows.
The SOC incorrectly stated that after expansion the 1000 colonies/100
ml would apply.

V
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4. IWC:
The IWC at 7 MGD is 3.4% - applies prior to the SOC.
The IWC at 9 MGD is 4.3% - applies during SOC.
The IWC at 13.5 MGD is 6.3% - applies after expansion.
In addition to Eden's questions, we have some additional
comments regarding the draft permit. First, as mentioned above,
effluent color monitoring (daily, composite) was left out of the
draft permit. Effluent monitoring of Mercury was also recommended in
our WLA but was not in the draft permit. Daily monitoring of
dissolved oxygen is not required since there is no DO limit.
Daily ammonia monitoring should be replaced by weekly monitoring.

1-
Gtay of Eden
April 16, 1990
Mr. Dale Overcash, Acting Supervisor
Permits and Engineering Unit
N. C. Department of Environment, Health,
and Natural Resources
P. 0. Box 27687
Raleigh, NC 27611-7687
Dear Mr. Overcash:
SUBJECT: DRAFT NPDES PERMIT NC0025071
MEBANE BRIDGE WASTEWATER TREATMENT PLANT
CITY OF EDEN
ROCKINGHAM COUNTY
We have reviewed the draft NPDES Permit for the Mebane Bridge Wastewater
Treatment Plant.
some questions arose during our review because of changes in the permit
language, and because of the issuance of Special Order by Consent WQ 89-54
during the NPDES Permit renewal process. The questions were framed
individually as the review proceeded. For this reason, some redundancy in
the questions occurs.
if the questions are not clear, please call me at 919-623-9921. Thank
you for taking the time to respond.
Sincerely,
Dennis Asbury
Public Utilities Director
c: Steve Routh, City Manager
Terry Shelton, Wastewater Superintendent
350 West Stadium Drive • Eden, North Carolina 27288-3299 • Fax [phone]

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REVIEW OF DRAFT NPDES PERMIT
/
NC 0025071
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FINAL:EFFLUENT LIMITATIONS AND MONITORING REOUIREMENTS
Color: An instantaneous daily maximum of 540 ADMI Color Units
�
has been set. The plant's current average discharge is �
approximately 1,100 ADMI Color Units. Since the Special
Order by Consent (SOC) WO 89-54 supersedes the NPDES
Permit limitations during the life of the SOC, are we
correct in assuming that the 540 limit and the
monitoring requirements in the draft permit will not
apply until the SOC expires?
No influent or effluent sampling is specified. Are we
correct in assuming that the 540 limit applies to the
plant effluent?
The two upstream and one downstream sample points
require the collection of three samples at points 1/4,
1/2, and 3/4 of the distance across the river. Can
these samples be composited and a single ADMI color
analysis be performed on the composite7�'D
A composite sample is specified. Are we correct in
assuming that the composite sample type refers to the
effluent and that upstream and downstream samples may
be grab samples?
NH3 as N In the draft permit NH3 as N must be monitored daily.
In the SOC NH3 as N must be monitored weekly. Are we
correct in assuming that the SOC supersedes the NPDES
permit for the life of the SOC?
Fecal In the draft permit the fecal coliform limit is 200 /
100 ml (monthly) and 400 / 100 ml (weekly). In the SOC
the fecal coliform limit is 1,000 / 100 ml (monthly)
and 2,000 / 100 ml (weekly). Are we correct in assuming
that the SOC supersedes the NPDES permit for the life
of the SOC?
8OC Certain parameters in the draft 'permit are either not
mentioned in the SOC or have different monitoring
requirements in the SOC than in the permit. Does the
SOC supersede the permit to the degree that monitoring
required by the NPDES permit but not required by the
SOC can be delayed until the expiration of the SOC?

85% Rule Does the 85% removal efficiency rule supercede the
NPDEG permit and GOC effluent concentration limits for
BOD5 and TS8? If so how is compliance judged on a
monthly basis and on a weekly basis? Are we correct in
assuming that the GOC supersedes the NPDEG permit for
the life of the 80C?
Foam What constitutes "...visible foam in other than trace
amounts"?
PART I
B.2. Does our historical record of operation and maintenance
constitute "optimum efficiency" as noted in this
section?
PERMITS:PART II STANDARD CONDITIONS FOR NPDES
B.3.b. In the past the Winston-Salem Regional Office (WSRO)
has accepted a written notice of rain caused bypasses
following cessation of the bypass in lieu of the
procedure called for in this section. Can we continue
this arrangement, if it is agreeable with the WSRO,
Without being in violation of the permit?
B.6. We keep detailed records of all bypasses and their
causes. It is extremely rare that a bypass is caused by
a power failure. It does not seem reasonable that DEM
would require standby power generation equipment or
retention facilities at all of the city's fifteen pump
stations. Does DEM have guidelines which specify when
and where alternate power sources are required? Where
can these guidelines be found?
D.6.d. This paragraph requires immediate notification of the
state when "...self -monitoring indicates that the plant
has gone out of compliance with its NPDEG permit
limitations." Does this mean that violations which
will be reported on the Monthly report must also be
reported by both telephone and follow-up letter? If
not, to what does this section refer? Does this section
require that we monitor the distribution of allowable
pounds of waste discharged on a daily basis to predict
in advance of end -of -the -month report generation that a
violation will occur?

PART III_gTHER REQUIREMENTS:
C. This paragraph revokes all previous State water quality
permits whether for construction, operation, or
discharge. Are we correct in assuming that this is
"boiler -plate" language and does not apply to our
Special Order by Consent WO 89-54 which was drafted
during the preparation of the subject draft NPDES
permit?
J
I. The IWC% in the draft permit is .3.4%. The IWC% in the
SOC WO 89-54 is 4.3%. Is this difference the result of
a transposition of numbers during the typing of the
documents? If not, why are the two IWC% figures
different. Also, if not, are we correct in assuming
that the SOC IWC% supersedes the draft permit IWC%
during the life of the SOC?
The schedule for the performance of Chronic Toxicity
Tests in the draft NPDES permit is different from that
in the SOC WO 89-54. Are we correct in assuming that
the SOC schedule supersedes the draft permit schedule
during the life of the SOW