NC0022730_Authorization to Construct_20040204

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dMP
Dave Goodrich
NC DENR / DWQ / NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Dear Dave:
DAVIS - MARTIN - POWELL & ASSOCIATES, INC.
ENGINEERING • LAND PLANNING • SURVEYING
218 GATEWOOD AVENUE • SUITE 102
HIGH POINT, NC 27262
PHONE [phone] • FAX [phone]
February 4, 2004
Re: Town of Beech Mountain
Grassy Gap WWTP
Project E-3161
ATC 02273^A01
Enclosed please find the Engineers Certification for the above referenced project.
The Town will place the relocated effluent pipe in operation on February 9, 2004. Please note that
during construction the equalization weir modifications were deleted, and a throttling valve added
to the equalization pump discharge to provide better control of the flow rates.
Also, please note that the facility location on the ATC has been corrected.
If you have any questions, or need additional information, please feel free to give me a call.
Sincerely,
DAVIS-MARTIN-POWELL & ASSOCIATES
Midh�?j L.,"slush r, PE
MLS/
DocumenN
file

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality Aia K
Michael F. Easley, Governor NCDENR
William G. Ross, Jr., Secretary
Alan W. Klimek, P.E., Director
PROFESSIONAL ENGINEER'S CERTIFICATION
FOR
CONSTRUCTION OF WASTEWATFR TREATMENT FACILITIES
ATC PROJECT NUMBER: 022730A01
Town of Beech Mountain — Grassy Gap W WTP
NPDES Permit No. NCO022730
I Michael L. Slusher am a duly registered Professional Engineer
01-1 n•q
in the State of North Carolina and have been authorized to observe (circle o : periodical) , weekly, full time)
the construction of the subject project for the Permittee:
Project No.: 022730A01
Project Grassy Gap WWTP Effluent Relocation
Watauga County
Location: N68R 152 Grassy Gap Creek Road
Beech Mountain, NC
The project consists of:
• A new effluent pump station with two pumps, each capable of pumping up to 340,000 gpd
• The installation of standby power generation with sufficient power to run one treatment train
• Relocation of the outfall line to a point at the confluence of Grassy Gap Creek and Buckeye
Creek
• Modifications to the current equalization system and replacement of equalization pump
impellers Revised to add a throttling valve to the existing pumps.
• The addition of the Grassy Gap W%V P into the Town's existing monitoring system such that
alarm conditions and loss of power may be indicated remotely at the Public Works Building
I hereby certify that I did regularly observe this project with due care and diligence and that
the construction was completed in substantial conformance with the Authorization to
Construct and with the a roved plans and specifications.
Signature Registration No. NC 20590
Date Fel ruari. 4. 2004
Upon completion of construction and prior to operation of the modified facility, the Permittee shall provide thi
Division with a certification from a professional engineer certifying that the permitted facility has been installed it
accordance with the NPDES Permit, this Authorization to Constrict, and the approved plats and specifications.
The Certification should be submitted to:
NCDENRIDWQ, NPDES Unit, 1617 Mail Service Center, Raleigh, North Carolina 27699-1617

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Alan W. Klimek, P.E., Director
Mr. Seth Lawless, Town Manager
Town of Beech Mountain
403 Beech Mountain Parkway
Beech Mountain, North Carolina 28604-8012
Dear Mr. Lawless:
ern
NCDEHR
February t0,2003
Subject: Authorization to Construct
ATC No. 022730A01
NPDES Permit No. NCO022730
Grassy Gap Wastewater Treatment Plant
Watauga County
The Division of Water Quality's NPDES Unit has reviewed your request for an Authorization to Construct
(ATC) at the Grassy Gap Wastewater Treatment Plant and finds the proposed improvements to be
satisfactory and hereby grants authorization for:
A new effluent pump station capable of pumping up to 340,000 gpd with only one functioning
PUMP.
• The installation of standby power generation with sufficient power to run one treatment train in
the event of a power outage.
• Relocation of the outfall line to a point at the confluence of Grassy Gap Creek and Buckeye
Creek.
Modifications to the current equalization system and replacement of equalization pump
impellers.
• The addition of the Grassy Gap WWTP into the Town's existing monitoring system such that
alarm conditions and loss of power may be indicated remotely at the Public Works Building.
This Authorization to Construct is issued in accordance with NPDES Permit No. NC0022730, issued
December 27, 2001, and shall be subject to revocation unless the wastewater treatment facilities are
constructed in accordance with the terms and conditions of the permit. This ATC does not alter the
existing permitted flow of 0.08 MGD.
The Permittee shall notify the Water Quality Supervisor of the Winston-Salem Regional Office, telephone
number (336) 7714600, at least forty-eight (48) hours prior to operation of the installed facilities, so that an
in -place inspection can be made. Notification shall be made during the normal office hours of 8:00 a.m. until
5:00 p.m., Monday through Friday.
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
An Equal Opportunity Affirmative Action Employer
Telephone [phone] FAX [phone]
Internet: hnp://h2o.enr.state.nc.us/

Grassy Gap WWTP
NPDES Permit No. NCO022730
ATC No. 022730A01
Page 2
Engineer's Certification
Upon completion of construction and prior to operation of the modified facility, the Permittee shall provide
the Division with a certification (copy enclosed) from a professional engineer registered in North Carolina
certifying that the permitted facility has been installed in accordance with the NPDES Permit, this
Authorization to Construct, and the approved plans and specifications. The Certification should be submitted
to: NCDENR / DWQ, NPDES Unit, 1617 Mail Service Center, Raleigh, North Carolina 27699-1617.
Reauirements for Certified Ouerator
The Permittee shall employ a certified wastewater treatment plant operator to be in responsible charge (ORC)
of the wastewater treatment facilities. The operator must hold a certificate of the type and grade at least
equivalent to or greater than the classification assigned to the wastewater treatment facilities by the
Certification Commission. The Permittee must also employ a certified back-up operator of the appropriate
type and grade to comply with the conditions of Title 15A, Chapter 8G, .0200. The ORCof the facility must
visit each Class I facility at least weekly and each Class It, III, and IV facility at least daily, excluding
weekends and holidays; and must properly manage and document daily operation and maintenance of the
facility and comply with all other conditions of Title I5A, Chapter 8G, .0200.
Additional Requirements
The Operational Agreement between the Permittee and the Environmental Management Commission is
incorporated herein by reference and is a condition of this Permit. Noncompliance with the terms of the
Operational Agreement shall subject the Permittee to all sanctions provided by G. S. 143-215.6 for violation
of or failure to act in accordance with the terms and conditions of this Permit.
Failure to abide by the requirements contained in this Authorization to Construct may subject the Permittee
to an enforcement action by the Division of Water Quality in accordance with North Carolina General Statute
143-215.6A to 143-215.6C.
The issuance of this Authorization to Construct does not preclude the Permittee from complying with any and
all statutes, rules, regulations, or ordinances which may be imposed by other government agencies (local,
state, and federal) which have jurisdiction.
The Permittee shall maintain a copy of the approved plans and specifications on file for the life of the
facility. One (1) copy of the approved plans and specifications is enclosed for your records.
If you have any questions about this Authorization to Construct, please contact Natalie Sierra, at (919) 733-
5083, extension 551.
Sincerely,
'Alan W. Klimek, PE
Enclosures: Project Plans and Specifications (approved)
Engineer's Certification Form
cc: Winston-Salem Regional Office, Water Quality
Technical Assistance and Certification Unit
Central Files
INUMMOM
Mr. . — Davis -Martin -Powell & Associates, Inc.
218 Gatewood Avenue
High Point, North Carolina 27262

ATC SUMMARY
SCOPE
Town of Beech Mountain
Banner Elk, NC
ATC No. 02273OA01
Grassy Gap Creek, Class C
Watauga River Basin, 040201
Watauga County
The scope of the project includes modifications to the current equalization system, a new effluent
pump station and outfall line to Buckeye Creek, and installation of standby power.
RECOMMENDATIONS
1. Approve modifications to the existing equalization system
2. Approve installation of an effluent pump station
3. Approve installation of an effluent force main (outfall) to Buckeye Creek
4. Approve installation of standby power
REVIEW SUMMARY
Executive Summary
The treatment works currently consist of:
• Influent bar screen
• Equalization
• Flow control box
*Dual path aeration basins and clarifiers
• Chlorine disinfection
• Dechlorination
The facility is having difficulty meeting its current BAT limits for ammonia nitrogen (2 mg/L in the
summer and 4 mg/L in the winter). In order to achieve greater dilution and obtain less stringent
ammonia limits, Beech Mountain has proposed moving the discharge to nearby Buckeye Creek,
which provides nearly five times the dilution of the current receiving stream. Speculative limits
were provided for this discharge point and a draft permit has been released with these limits (July
2002).
In addition to the new effluent pump station and outfall, some modifications are proposed for the
equalization system such that all inflow is directed to the equalization zone (instead of to the
aeration basins) first, then on to the aeration basins. This improved schematic should facilitate
treatment of the wastewater.
Diesel fueled backup power sufficient to run one treatment train is also being proposed
-end-
Pagel

ATC REVIEW NOTES Town of Beech Mountain
ATC No. 022730A01
Watauga County
Project Name: Grassy Gap WWTP Effluent Relocation
Applicant:
Mr. Seth Lawless
Town of Beech Mountain
403 Beech Mountain Parkway
Beech Mountain, North Carolina
Application/Plans Prepared by:
Michael Slusher, P.E.
Davis -Martin -Powell & Associates, Inc.
High Point, North Carolina
Project Location:
Grassy Gap WWTP
Grassy Gap Creek Road
Near Beech Mountain
Watauga County
Chronology:
APP RECD
09/05/02
REVIEWED 11/5/02
ACKNOWLEDGED
10/18/02
SCHTOISSUE 02/17/03
STAFF RPT REQS
10/ 18/02
ADD INFO REQS
STAFF RPT RECD
11/ 15/02
ADD INFO RECD
Submissions:
• Letter of 1Y-ansmittal
• Engineering Plans and Specifications
• Executive Summary
Effluent Pumps
Number of pumps: two
Pump type: 8.75" Impeller, -1625 RPM, 15 -HP
Pump capacity: 250 gpm at 55 ft. TDH
Effluent Piping
Material proposed: either ductile iron pipe or PVC pressure pipe
Diameter: 6"
Review Notes:
The reconfiguration of the equalization basin requires a new inlet chute that will divert flow from
the headworks into the equalization basin. The impellers will be replaced on the equalization
pumps to minimize flow surges by pumping closer to the design rate. If the equalization basin fills,
the wastewater overflow will flow into the influent channel, where it will be diverted to the aeration
basins. A new flow control box will control the flow from the equalization basin into the aeration
basins and will assist in maintaining an even flow rate into the aeration basins. The above
improvements should assist in making the aeration basins more efficient in pollutant removal.
The effluent pumps are capable of pumping over 2.5 times the design flow (80,000 gpd) with one
pump out of service. High water and other visual alarms will be installed on the pump station.
Page 2

ATC REVIEW NOTES
Town of Beech Mountain
ATC No. 022730A01
Watauga County
Since the W W1P does not currently have standby power, a generator is proposed that would allow
one treatment train to function in the event of a power loss.
Compatibility with existing equipment: The proposed project is compatible with the existing
treatment system and adds a measure of operational control and safety to the plant. The feed
points will be identical to what they are with the chlorine gas system.
Recommendations
I recommend that the Authorization to Construct be issued. The improvements delineated in this
ATC allow for more reliability (by adding backup power where there was none before and
reconfiguring the equalization basin for optimum treatment) and possibly better treatment. The
Division has already given approval for the relocation of the outfall and this work should be done
as soon as possible.
Page 3

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Beech Mountain. Grassy Gap WWTP
Subject: Beech Mountain, Grassy Gap WWTP
Date: Wed, 6 Nov 2002 13:50:23 -0500
From: "Mike Slusher" <[e-mail]>
To: "Natalie Sierra \(E-mail\)" <[e-mail]>
CC: "Seth Lawless \(E-mail\)" <[e-mail]>
Town of Beech Mountain
Grassy Gap WWTP
ATC 022730A01
Natalie,
Please find the additional information we discussed this morning.
Sheet 4. WWTP Modifications
The equalization inlet channel was originally designed to flow directly into aeration basins, with overflow weirs
directing flows above 80,000 GPD into the equalization basin. This arrangement has not satisfactory reduced
intermittent flow peaks, and we are modifying the inlet to divert all flow into the equalization basin.
❑ Equalization Pumps are existing, however the impellers will be replaced (see Note 7), this will minimize the
flow surges by pumping closer to the 80,000 GPD rate. All flow will now be pumped through the WWTP, unless
the inflow into the plant fills the equalization tank, when will overflow into the influent channel and pass thru the
aeration basins.
❑ Proposed Inlet Chute (see Flow Control Box Detail, lower left corner) will divert inflow into the equalization
basin.
❑ Proposed Flow Control Box is designed to minimize turbulence from the EQ Pump discharge and combined
with relocating the existing V-Notch Weirs (to provide a longer approach channel) will improve both the flow spit
and the ability to maintain an even flow rate.
❑ One broken EQ pump check valve will be replaced.
❑ Detail A — these End Plates are proposed to fill the gap between the two halves of the package plant to
prevent surface runoff from entering the WWTP.
u EQ basin volume is 20,160 gallons (25% capacity).
Electrical
The WWTP currently does not have standby power. The proposed standby generator will be sufficient to operate
the uncontrolled load, one EQ pump, one blower, and the lead effluent pump.
11/6/02 1:56 PM

,a
Bqech Mountain. Grassy Gap W WTP
Effluent Outfall / Forcemain
Pipe material will be either ductile iron or PVC pressure pipe, SDR 21. (Spec page 02730-1,2)
Entire forcemain will be 6" diameter (labeled on profile).
There is no flap valve proposed at the discharge
The effluent pumps have been sized to pump 360,000 GPD, which exceeds the highest recorded flow rate (340,000
GPD).
The Town began construction on the first phase of sewer system I/I rehab in this basin in October, which should
significantly reduce the I/I problem. Funding is being sought for continued I/I rehab projects. We are completing a
201 Plan Amendment to qualify for SRF funding.
I hope this helps your review. If you have any further questions, please feel free to call.
Mike Slusher, PE
Davis -Martin -Powell & Associates
[phone] / Fax [phone]
mailto:MS[usher(@dmp-inc.com
2 of 2 11/6/02 1:56 PM

A
Cc: Permits and Engineering
Technical Support Branch
County Health Department
Central Files
WSRO
SOC PRIORITY PROJECT: YES NO X
IF YES, SOC No.
To: Permits and Engineering Unit
Water Quality Section
Attention: Natalie Sierra
AUTHORIZATION TO CONSTRUCT
NPDES PERMIT REPORT AND RECOMMENDATIONS
Date: November 12, 2002
County: Watauga
Permit No.: NCO02273OA01
PART I -GENERAL INFORMATION
1. Facility Name and Current Address:
Town of Beech Mountain, Grassy Gap Wastewater Treatment Plant
403 Beech Mountain Parkway
Beech Mountain, NC 28604-8012
2. Date of most recent Staff Report:
August 16, 1995
3. Changes since previous action on NPDES Permit:
Moratorium in effect since 12/00
4. Verify Discharge Point(s) on plans with current NPDES Permit. List for all discharge points.
Latitude: 36 13' 19" Longitude: 81 54' 20"
Attach a USGS map extract and indicate treatment facility site and discharge point on map.
U.S.G.S. Quad No. C-I I SW U.S.G.S. Quad Name Elk Park
5. Treatment Plant Classification: III
PART II — DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. Existing treatment facility
a. What is the current capacity of the facility?
0.08 mgd

b. What is the actual treatment capacity of the current facility (design volume)?
0.08 mgd
c. Please provide a description of existing or substantially constructed wastewater treatment facilities.
Includes a 0.08 mgd extended aeration package plant consisting of influent flow equalization,
instrumented flow measurement, manual bar screens, aeration tanks, clarifiers, liquid chlorine
feeding, chlorination chamber, dechlorination, and sludge holding tanks.
2. Please provide a description of proposed wastewater treatment facilities:
A 250 GPM effluent pump station and forcemain to the proposed discharge at the confluence of Buckeye
Creek and Grassy Gap Creek, per 2001 permit modification.
A standby generator sized to operate major treatment components including the effluent pump station in
the event of a power failure.
Modifications to the existing flow equalization system to minimize process surges.
3. Residuals handling and utilization/disposal scheme:
a. If residuals are being land applied, please specify DENR Permit No. na
b. Residuals stabilization: PSRP_ PFRP X
C. Landfill: na
d. Other disposal/utilization: Distribution of Class A Residuals via permit no. W00002523. Residuals are
hauled from the site to the Pond Creek plant for dewatering and composting or are disposed of using a
pump truck and are hauled to a municipal wastewater treatment plant.
4. Important SOC, JOC, or Compliance Schedule dates, if applicable:
SOC currently in draft form. Dates are not final.
PART III — EVALUTION AND RECOMMENDATIONS
Recommendation is made to issue the Authorization To Construct in accordance with division policy.
4,r L (i
Signature of Report Preparer
Water Qua ty Supervisor
2--
Date