NC0021873_Plan of Action_19840418

NPDES DOCUMENT !;CANHINC COVER SHEET
NPDES Permit:
NC0021873
Mayodan WWTP
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
w P/f4 F461
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
April 18, 1984
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DIVISION OF ENVIRONMENTAL MANAGEMENT
April 18, 1984
MEMORANDUM
TO: Walter Taft, Chief
Construction Grants
FROM: W. Lee Fleming, Chief 0,24
Water Quality Sectio
SUBJECT: Stand-by Power Requirements for the Mayodan WWTP --
Mayo River, Rockingham County
SUMMARY
In response to a letter from Bill Hoffman of your staff, the
Technical Services Unit has completed an evaluation of stream response
to a disinfection unit failure at the Mayodan WWTP. Because of the
technical difficulty involved with modeling fecal coliform, a high
degree of uncertainty is associated with model predictions of stream
response to such an occurrence. However, under a wide range of model
inputs, six out of eight model runs predicted that fecal coliform levels
would be substantially higher than background levels at the nearest point
of water intake. In consideration of the size of the Mayodan WWTP, along
with the potential magnitude of impact, I am recommending that stand-by
power be required at this facility.
ANALYSIS AND RESULTS
The Mayodan WWTP (design flow = 1.3 MGD) discharges to the Mayo
River 1.3 miles upstream of its confluence with the Dan River. This
portion of the Mayo River is classified as "C" waters, whereas the Dan
River is classified as "A -II". The Town of Madison WWTP (design flow =
.775 MGD) discharges its effluent to the Dan River immediately upstream
of its confluence with the Mayo River. Figure 1 displays these relation-
ships.
A simple exponential decay model was used to evaluate various stream
conditions. This model is based upon a steady state assumption. Extremes
of the most likely ranges of parameters were input for streamflow,
effluent fecal coliform concentration, fecal coliform disappearance rate,
and travel time to the nearest point of intake along A -II waters. At
present, the closest downstream water intake is located in southwest
Eden, approximately 17 miles below the confluence of the Mayo and Dan
Rivers. Model input and output for these conditions are shown in Table 1.

Hr. Walter Taft
Page 2
April 18, 1984
As is evident from review of Table 1, a wide variety of outcomes is
possible. However, for six of theeight runs completed, fecal coliform
levels at the point of intake were predicted to be substantially higher
than background levels. From a conservative standpoint, it appears
likely that elevated fecal coliform levels at the Hayodan outfall could
result in significant elevation of coliform at the downstream point of
intake.
WLF/jf
cc: Forrest Westall
Trevor Clements
attachments

TABLE 1
MODEL INPUT AND OUTPUT
Flow
Effluent
Fecal Coliform
Travel Time
Predicted F.C.
Condition
F.C.Conc.
Disappearance
to S.W. Eden
Conc. @ Intake
(7Q10 or Avg.)
(/100m1)
Rate(/day)
Intake (hrs.)
(/100m1)
Avg
2,000,000
0.8
8 hrs.
3,760
7Q10
2,000,000
0.8
34 hrs.
12,570
Avg
2,000,000
3.6
8 hrs.
1,620
7Q10
2,000,000
3.6
34 hrs.
620
Avg
400,000
0.8
8 hrs.
870
7Q10
400,000
0.8
34 hrs.
2,580.
Avg
400,000
3.6
8 hrs.
Background
7Q10
400,000
3.6
34 hrs.
Background
Note: Results represent disinfection unit failures at both the Mayodan WWTP and the Madison WWTP

Mayaaan VWTP
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MEMORANDUM
'10:
FROM:
SUBJECT:
DIVISION OF ENVIRONMENTAL MANAGEMIHNT
April 3, 1984
Randall Williams
NCDEM Operations Branch
Bill Hoffilmansgji f;‘°)
NCDEM Construction Grants Section / -.17
Engineering Management Unit �/� `j
Town of Mayock-�n 1,4/v
CC
Standby Power Requirements forW ,
Wastewater Treatment (Collection Facilities Not '--b :Vjoi)"
Located Immediately Adjacent to A -II or B Waters)
EPA Project No. C370466-02 Cd Ct
NPDES Permit No. NO0021873
Due to the limited monies which the State/EPA have to fund wastewater
facilities, we are required to deterinine the.reasonableness and necessity of
proposed facilities. We are currently reviewing the design of the subject
facilities (A -II, B Waters not immediately adjacent) in regard to the need/
requirement for standby power to operate the facilities in the event of a
power outage.
The following information is provided for your determination of degree
and duration of standby power or standby holding capacity to be required for
the subject facilities:
1. Map of location of facilities is attached.
2. This is no record of the power outage history for the location of
the new WWTP. However, the Duke Power Co. local representative for
the Madison area has indicated that based on his experience and
memory, outages in the proposed WWTP location area are infrequent
and do not exceed thirty (30) minutes and that Duke Power records
for the Madison area indicate the longest outage in the last ten
years to be four (4) hours in March, 1983.
3. Electrical apparatus is required at wastewater treatment plant and
lift stations (not on A -II, B Waters) for hook-up of loaned/rented
portable standby power generator during extreme periods of outage.

Randall. Williams
Page Two
April 3, 1984
4. Storage time in system prior to overflow at ADF is one hour and
twenty minutes.
5. If the influent lift station is provided with standby power, primary
treatment for flow of 1.25 MGD with influent BOD of 300 mg/1 should
be obtained, resultigg in BOD = 210 mg/1 and fecal coliform of
MPN/100 ml = 20 X 10 .
If raw untreated discharge is not allowable during a power outage, we
need to be notified if complete or partial plant operation (complete or partially
treated wastewater) will be acceptable for water quality. The size and cost of
the standby power unit will be based on this determination.
Your cooperation in this matter and prompt response will be greatly
appreciated. -
If you have questions, please contact me or Larry Horton, the project
engineer, at 919/733-6900.
LH:tm
Enclosure
cc: Mr. Russell Radford
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Jerry R. Carlton, Manager
Debra E. Cardwell, Clerk
D. Leon Moore, Attorney
L. E. Shelton, Police Chief
Thomas L. Williams, Fire Chief
NC 00 2.1 S 3
TOW 1\1.. E ,M! fYODAN.
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JAMES A. COLLINS, .M,OR
t.
' �cr .r _ ti i ;14 :7J:
November 10, 1983
OvK,Cif71 D• 3 s
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Mr. Robert.F. Helms, Director
N.C. Dept. of Natural Resources and Community Development
Division of Environmental Management
P.O. Box 27687
Raleigh, N. C. 27611-7687
Dear Mr. Helms:
COUNCILMEN
fi"Slitprin, Mayor Pro-Tem
1983
Lewis Bottoms
Reginald Cardwell
Buddy Martin
Bill VanHoy
•
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WATER (UAt..�<<iY�%
.
We are sending this correspondence to seek your assistance on a matter that
is very important to the Town of Mayodan. As you are aware, our Town's
sewage treatment facilities are old, and in the past, we have experienced
difficulties in complying with the conditions established in our NPDES permit.
As a consequence, we were granted a Special Order by Consent from the Division
of Environmental Management to allow us to continue to discharge wastewater.
The Consent Order establishes certain limits, schedules, and conditions for
the Town of Mayodan, and we have made every effort to comply with the conditions
set forth in the Consent Order.
I would like to summarize for you the progress and work that has been completed
to date to improve the effluent quality from the Mayodan Sewage Treatment Plant.
1. Effective July 1, 1983, we contracted with Hydro Management Services,
Inc. of Winston-Salem, N. C. to provide us with professional
management and operation of our sewage treatment facility.
2. We have contracted with a certified independent laboratory to perform
our analyses.
3. The plant is being checked and monitored seven days per week.
P.O. Box 498, Mayodan, N. C. 27027
"A COMMUNITY OF EXCELLENCE"

Mr. Robert F. Helms
Page 2
November 10, 1983
4. The old bar screens at both the Washington Mills pump station and
the influent have been replaced with screens that have smaller
openings, so as to allow capture and removal of more solid materials.
5. The anaerobic digester has been repaired and is now functioning and
producing methane gas.
b. The influent flow meter has been re -worked and calibrated, and is
functioning properly.
7. The automatic level controller for the trickling filter recycle
pumps has been replaced. This has provided for automated control
of the pump which insures that the trickling filter will operate
continuously.
8. The effluent chlorinator has been completely rebuilt and is
functioning properly.
9. We have secured permission from Washington Mills to use the large
settling basin adjacent to the plant site as a hydraulic and organic
equalization -basin. We presently have the pumps on hand, and are
preparing to install them so as to allow us to utilize this basin.
I believe that the foregoing discussion will demonstrate the Town of Mayodan
is committed to improving its wastewater treatment system, and complying with
the conditions set forth in the Consent Order. Our objective is to produce
an effluent that is in compliance with secondary treatment limits. As you
will note in the attached summary, we feel that we have made significant
improvements in the effluent quality. The average effluent BOD for July
through October, 1983 was 37 mg/1, and the average effluent Suspended Solids
for the same period was 28 mg/1. We feel that we will see further improvement
in the effluent quality by including the Washington Mills settling basin in our
treatment scheme.
Mr. Helms, we realize the importance of a good, well -operated sewage treatment
facility, and we trust that the foregoing discussion has demonstrated to you
the Town of Mayodan's committment to maintain and operate our treatment facility
properly. It is also important that the Town be able to grow and expand our
tax base, and thus, the purpose of this correspondence.
The Landura Corporation of Winston-Salem is in the process of securing financing
to construct an apartment complex consisting of 44 living units in Mayodan,
North Carolina. In order to complete financing and commence construction, the
Landura Corporation requires assurances that they will be able to connect to
our sewer system.
The wastewaters generated from the apartment complex will be entirely domestic
wastewaters. Our consultants estimate the average daily quantity of wastewaters

Mr. Robert F. Helms
Page 3
November 10, 1983
generated will be less than 9,000 gallons per day, which would represent less
than three percent of our present average daily flow. Further, the entire
9,000 gallons per day will not be received at the plant until the late summer
of 19 84 .
Mr. Helms, based on the significant improvements we have made at our sewage
treatment plant and the expected continued improvement in effluent quality,
the Town of Mayodan respectfully requests permission to be allowed to connect
this apartment complex to our system.
Your expeditious approval of our request will be greatly appreciated. If you
have any questions or require any additional information, please feel free to
contact me at your convenience.
With best regards,
Sincerely,
TO 0D
R. Carlton
Town Manager
ATTACHMENT
cc: Mr. Russell Radford, NCNRCD, Winston-Salem
Mr. Ron Midura, Landura Corporation
Mr. C. D. Malone, Hydro Management Services, Inc.

r'
SUMMARY OF MONTHLY EFFLUENT QUALITY
TOWN OF MAYODAN, NORTH CAROLINA
DATE FLOW, MGD BOD, mg/1 SS, mg/1 FECAL COLIFORMS, Co1/100m1
July, 1983 0.232 13 26 <2
August. 1983 0.300 51 28 < 2
September, 1983 0. 284 35 23 <2
October, 1983 0. 290 , 50 36 < 2
Consent Order
Limits
0.700 80 100 1000