NC0057703_Engineers Certification_20170512

N Ak
May 12, 2017
Mr. Ron Berry
Complex Permitting Unit
DEQ/DWR/Water Quality Programs
1617 Mail Service Center
Raleigh, NC 27699-1917
RE: ENGINEERS CERTIFICATION
The Cape WWTP Flow Eq. Tank
Authorization to Construct No. NC 057703A05
Dear Mr. Berry,
Aqua North Carolina, Inc. (Aqua) is pleased to inform you that construction of the above
mentioned project is complete. Startup occurred on March 22, 2017 to evaluate the proposed
equalization tank and associated equipment. During startup it was identified that the existing
pumps were not capable of providing the identified pumping flow rate. After much
investigation, it was identified that a faulty valve was installed increasing dynamic head
conditions and preventing the pumps from achieving their design pumping rate. However,
prior to the valve being identified as faulty, to prevent a sewer bypass Aqua mobilized quickly
to replace the existing pumps with new 15 -HP pumps. See attached pump curve. Due to the
increased pumping rate, Aqua also replaced the existing 4" piping with 6" diameter ductile
iron piping. Preliminary draw down data indicates the new pumps provide a maximum flow of
700 gpm, which provides for a peaking factor of 3.89 and 2.52 at the current and future
permitted ADF of 0.26 and 0.40 MGD, respectively.
Regarding the approved plan set and ATC, the approved plan set identifies two (2) flow
equalization pumps each rated for 325 gpm at 12.6 ft TDH. The ATC identifies three (3) new
pumps rated for 325 gpm at 12.6 ft TDH. Please recall the letter from the Design Engineer,
Mr. Michael Wicker, PE with Withers and Ravenel, dated June 10, 2016 that provides a
response to your comment requiring that a single flow equalization pump provide a peak
hourly flow rate of 307 gpm at the current permitted design rate of 0.26 MGD with a 1.7 peak
factor. As designed, the installed duplex pump system meets the design criteria of pumping
the hourly peak flow of 307 gpm with a single pump out of service. Provisions were installed
for a future pump; such provisions include pump base and rails, as well as electricity. The
next proposed expansion at this facility is to 0.40 MGD, which will require a peak hourly flow
of 472 gpm with a single pump out of service. At this time a third pump shall be installed.
202 MacKenan Court, Cary, NC, 27511 • 919.467.8712 • AquaAmerica.com

Engineering Certification May 12, 2017
The Cape WWTF Flow Eq. Aqua North Carolina, Inc.
When two pumps are running, the design flow of each pump is 275 gpm, for a total flow of
550 gpm. This is greater than the peak hourly flow.
Lastly, please note this is a partial final certification, as Aqua has placed the flow equalization
basin into service and has yet to install the proposed screening and grit removal. It is
anticipated that the screen will be installed by March 2018. At that time a final certification
will be provided.
Aqua appreciates your dedication and commitment to this projects success and looks forward
to your concurrence of the proposed improvements. If you should have any more questions
or have further comment, please contact me via phone or email at [phone]
[e-mail].
Sincerely,
Michael D. Poulios, PE
Engineering Manager
Aqua North Carolina, Inc.
21 Page

Aqua North Carolina, Inc.
The Cape WWTP
Authorization to Construct No. 057703AO5
Issued June 29, 2016
Engineer's Certification
I, NIL , as a duty registered Professional Engineer in
the State of North Carolina, having been authorized to observe (periodically/weekly/full time)
the construction of the modifications and improvements to The Cape Wastewater Treatment
Plant, located in New Hanover County, hereby state that, to the best of my abilities, due care and
diligence was used in the observation of the following construction:
Installation of new headworks consisting of a single unit for peak flow 700 GPM with
piping, auxiliary conveyors, blowers, wash systems, and other controls; Inst ion
of a new flow splitter box with mechanical bar screen, piping, and ontrols;
installation of a new 100,000 gallon EQ basin with coarse air diffus ystem, two
(2) 140 SUM blower, piping, and controls; installation of three (3) new 325 GPM
at 12.6 ft TDH EQ submersible pumps; in conformity with the project plans,
specifications, and other supporting data subsequently filed and approved by the }
Department of Environmental Quality.
I certify that the construction of the above referenced project was observed to be built within
substantial compliance, intent and in conformity with all applicable regulations and statutes and
the project plans, specifications, and other supporting documentation comprising the
Authorization to Construct Permit Application package.
Signatur , Registration No.
C �3a q3
Date. 2_
Mail this Certification to- Attn: Ron Berry
Complex Permitting Unit
DEQ/DWRJWater Quality Programs
1617 Mail Service Center
Raleigh, NC 27699-1617

Technical Information
AVX444-220/15P/C
Operating data
Flow
600 US g.p.m.
Head
40 ft
Shaft power P2
13.8 hp
Pump efficiency
44.2%
Required pump NPSH
4 inch
Pumpe type
Single pump
No. of pumps
1
Fluid
Water, clean
Pump
AISI430 F Stainless Steel
Pump Code
AVX444-220/15P/C
Impeller
Vortex impeller
Impeller size
Vie"
Solid size
4 inch
Discharge port
4" ANSI
Suction port
DN100
Motor
AISI430 F Stainless Steel
Rated voltage
230/ 460V
Frequency
60 H;
Rated power P2
15.0 hp
Rated speed
1750 rpm
Number of poles
4
Efficiency
89.4%
Rated current
38 /19A
Degree of protection
IP 68
Materials
Motor housing Cast Iron ASTM A48;CI.40B
Impeller Cast Iron ASTM A48;CI.40B
Pump housing Cast Iron ASTM A48;CI.40B
Motor shaft
AISI430 F Stainless Steel
Bolts
AISI 304 Stainless Steel
Elastomeres
Nitrile Rubber
Mechanical seal on motor side Sic/ Sic
Mechanical seal on medium side sic/sic
Lower Bearing Two angular ball bearings
Upper Bearing Deep Groove Ball Bearing
1-1 IN1�
P U M P E N M I T S Y S T E M
Testnorm: P2>10kW, HI Standard Grade 2B
P2<10kW, HI Standard Sect. 14.6.3.4.1
Wet well installation on ground (P, 210...230)
Dimensions in mm [inch], letters see table
rain 1
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Table Dimensions
(inch }
-- m
H
38%
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