NC0069841_Authorization to Construct_19950327

NPDES DOCUMENT SCANNING: COVER SHEET
NC0069841
Crooked Creek WWTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
'Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Technical Correction
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
March 27, 1995
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State of North Carolina
Department of Environment,
Health and Natural Resources
' Division of Environmental Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
March 27, 1995
Mr. Mike Shalati
Union County Public Works Department
P.O. Box 987
Monroe, North Carolina 28111
Av477A
LDEEF-INJ I
Subject: Authorization to Construct
Permit No.. NC0069841
Union County - Crooked Creek WWTP #2
Union County
Dear Mr. Shalati:
A letter of request for an Authorization to Construct was received November 4, 1994 by the
Division and final plans and specifications for the subject project have been reviewed and found to be
satisfactory. Authorization is hereby granted for the construction of the following wastewater treatment
improvements:
• Expansion of two (2) existing oxidation ditches from 975,000 gallons (total) to 1,760,000
gallons (total);
• Two (2) new 38-foot diameter clarifiers;
• Two (2) new chlorine contact basins for a total of three (3), for a total capacity of 40,500 gallons;
• A new sulfur dioxide injection box and feed system;
• A new sample box;
• Four (4) new 120 square foot tertiary sand filter cells, for a total of six (6) cells;
• One (1) 45-foot diameter aerobic digester with one (1) 30 HP floating aerator;
• Two (2) 76-foot diameter aerobic digesters/thickeners each with (1) 75 HP floating aerator,
• One (1) 76-foot diameter sludge holding tank with one (1) 75 HP floating aerator;
• A new sludge transfer station with two (2) 200 GPM sludge transfer pumps;
• A raw sewage wetwell pump station with two (2) 700 GPM influent pumps;
• Replacement of an existing return sludge pump with one (1) 635 GPM pump;
• Two (2) 1440 GPM filter backwash pumps;
• A 600 kW standby power generation system;
and all associated piping, valves, controls, and appurtenances with discharge of 1.0 MGD of treated
wastewater into South Fork Crooked Creek in the Catawba River Basin.
This Authorization to Construct is issued in accordance with Part III, Paragraph C of NPDES
Permit No. NC0069841 issued December 29, 1994, and shall be subject to revocation unless the
wastewater treatment facilities are constructed in accordance with the conditions and limitations specified in
' Permit No. NC0069841.
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post -consumer paper

Permit No. NC0069841
Authorization to Construct
Union County
March 27, 1995
Page 2
The sludge generated from this treatment facility must be disposed of in accordance with G.S. 143-
215.1 and in a manner approved by the North Carolina Division of Environmental Management.
In the event that the facilities fail to perform satisfactorily, including the creation of nuisance
conditions, the Permittee shall take immediate corrective action, including those as may be required by this
Division, such as the construction of additional or replacement wastewater treatment or disposal facilities.
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 8A, .0202. The ORC of
the facility must visit each Class I facility at least weekly and each Class II, 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 must comply with all other conditions of Title 15A, Chapter 8A, .0202.
A copy of the approved plans and specifications shall be maintained on file by the Permittee for the
life of the facility.
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 Environmental Management 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.
One (1) set of approved plans and specifications is being forwarded to you. If you have any
questions or need additional information, please contact Greg Nizich, telephone number 919/733-5083,
extension 541.
Sincerely,
4-A. Preston • ard, Jr., P.E.
cc: Union County Health Department
Construction Grants, John R. Blowe
Mooresville Regional Office, Water Quality
Training and Certification Unit
Central Files
HDR Engineering, Inc., Eric Williams
NPDES Files

Z0-14-`)5 UNlonl Couhrry - CRooiceD CReEk*2
AC606964/ GSA
WASTEWATER TREATMENT FACILITY
DESIGN UNIT CHECKLIST
1. Equipment list: This information is needed in writing the facility description.
EV AL., Fog t .9 MGD .-
Influent aurae tank
Y I
N
C;,pacity:
Grit removal chamber
N
flow splitter box
NJ
Bar Screen
y
Comminutor
N
Flow Measurement Device
Tvpe: (influent. effluent)
DATioo
Aeration Tank D� TrHe-s
NINumber
& Capacity: a1. 7(0MG.D ToTL
Clarifier/ erl Final settle tank
Y
G- 0.41s r-+ fad
Number & Capacity: S 8 ' DA tiElt-ii.
Sludoe Holdino Tank
,
Number & Capacity:
Blowers
Number & Capacity:
•
Tertiary Filters
Number & Area/ Filter: Co — 72O6F -rim
Chlorine Contact Tank
S 4CL U OT Ise -�C A'feb
Capacity: 3 -l3Asiras 4v,5—ao�g1- -61
Chlorinator
Y
Tvpe: 6-7f4&O vS
Residual Chlorine Removal
.
0
post Aeration Tank
Y
•
Shice..)c-a Avar 3E i/l CL . C0Ar --7"
Sz`�C G�sc•� �i&
Effluent Dosing Tank
_
Ci pa it :
Siudae Handling Eouio
_
Stand-by Power
_
_ Tvpe:
2. Check design parameters and NPDES Permit limits:
v a VerifyNPDES flow: Q >_ Design Q.
V b. if effluent BOO _< 18 mg/l, and TSS < 30 mg/I then tertiary treatment is

required. Tertiary treatment shall consist of aeration detention of at least 24
hours and tertiary filters. If BOD <_ 5 then aeration detention shall be at least
36 hours unless the applicant can show that limits can be met with Tess aeration
detention.
c. If fecal conform 5 1000#/ 100m1, then disinfection is required. -
d $f a residual chlorine limit is imposed, then dechlorination is required. This is
already required for discharges into 'Trout' classified waters.
If effluent dissolved oxygen (DO) z 5 mg/I, then post aeration is required.
Tos-r eR pRcc LI S MALLNALL UOT 13 C 1:to).1 E 11.1 "T•te Ct coy.; r r
If a phosphorus limit is imposed, then phosphorus removal facilities are
required.
3. Equalization basin: Required for all facilities. — Nor RE6?'D . 1P AK Flows.
N(1SI 26D }oe
5
Working volume - 20 to 25% of average daily volume.
4. Verify aeration requirements:
a. Detention time = volume! l,76,0%aav i 9a1. 24 hours/ day 24 hours
(I,9 oa, op) GPD 2Z2. 23 H.
b. Calculate BOD loading:"
lb BOD/ day = Zoo mg4. 8.34 •O ( t'9 ) MGD
s s t &, ✓
lb BOD/day
"Note: Use inflent BOD : 300mg/I for facilities discharging to SA or SB
waters in coastal regions; otherwise BOD = 200 mg/I should be used.
c. Calculate air needed for BOD removal:
CFM for BOD removal = ?.100 CFM/ lb BOD • 3 I tdg lb/ day =
1440 min/ day
4LoZI CFM
d Calculate air needed for mixing:
CFM for mixing = 25 CFM • aeration lank volume in gal9n (1,7 Ca) L'a
1000 CF • 7.48 gaV CF
6SkSr CFM
Use larger CFM value from (c) and (d) in calculating total air requirements.

•
5. Sludge Holding Tank:
a. Calculate air needed for digestion:
CFM = 20 CFM • Svdoe ink volume ( 1 yaI 3 _ CFM
1000 CF • 7.48 gaVCF
b. Verify sludge capacity:
PE z Population Equiv. _ ? f ' GPD =
100 GPD/person
Per capita sludge capacity = Sludoe tank volume f 1 gal = -
PE( )•7.48gaVCF
Per capita sludge capacity must be Z 1 CF/ person? YES ___, NO
b. Total air requirements:
a. Equalization ( may have separate blower) CFM
Aeration Tank CFM
Sludge Holding Tamk CFM
Air Lifts @ 10 CFM/ lift CFM
Post aeration @ 20 CFM/ 1000 CF volume CFM
TOTAL CFM
Blower Capacity CFM, TOTALS BLOWER CAPACITY
b. Blowers Provided:
1 aeration tank - 2 blowers
2 aeration tanks - 3 blowers
additional blower for equalization tank
c. Each blower unit should be equipped with a check valve and gate valve.
7. Clarifier/ Final Settling Tank:
a. Calculate detention time:
Detention time =,volume of clarifier f 1 I 76y 1 gal • 24 h /dav
Q(y75,00a )GPD
Detention time = G hours

Should be >_ 4 hrs for plants <_ 0.05 MGD
a 3.6 hrs for plants 0.05 MGD to 0.15 MGD
z 3.0 hrs for plants over 0.15 MGD
b. Calculate surface oading rate: -
Surface loading rate 0 (4"75, ood' GPD s 42 d GPD/ ft2 dlc.
Area (I 139 ) ft2
Should be < 300 GPD/ ft2 for plants 5 0.05 MGD
5.450 GPD/ ft2 for plants 0.05 to 0.15 MGD
5600 GPD/ ft2 for plants over 0.15 MGD
c. Calculate weir loading rate: Pea. cLAR I F•
Weir loading rate = Q (4175, vov ' GPD = 3'sq -19
weir length (l 19 ) 11
GPD/ ft bk
Weir loading rate shall be S 10,000 GPD/ ft.
8. Chlorine Contact Tank: S Kc& '1crr 13E AvaA+r'Eb
a Calculate contact time:
Contact time tank volume ( 40, SD0 cal • 24 hrs/ day = d 5 I hrs oic-
Q (I,Mjoo, 000 ) GPD
Contact time shall be a 0.5 hours and should be baffled.
b. Method of chlorination: 6A-5ec'5
tablet chlorination is satisfactory for Q < 50,000 GPD
9. Tertiary Filters ( dual filters required ):
a Filter loading rate:
loading rate Q (i too)000 ' GPD : I . f33
area of filters ( 72b ).ft2.1440
loadingrate shall be � 1.25 GPM/ ft2 M CALF 4 EI)Dy P' G 7tis4y5sEmi'z6-7G, 9p.. JFt2
le; ,cc.6PTA6L ER w Y Pl c.4 L.
b. Clear well capacity for backwash storage:
minimum capacity needed
filter area ( 120 ) ft2 • 15 GPM/ ft2. 10 minutes
I8, 000
gal 39 , 000 ok
GPM/ ft2

c. Mud well capacity:
Backwash volume
Inflow during backwash
= O (ig00)avCj 1• 10 mirt
1440
TOTAL
2ov gal
13, VT gal
20, 39 4 gal L av° z
Total shall be <_ mud well volume
d. Filter media specifications: la" M n1 6 RAD£ D F I Al E sA ND
Filters shall have at least WIC inches minimum depth of sand and anthracite.
10. Miscellaneous items to be addressed:
a. Sludge disposal information should be provided, indicating how, where and by
whom sludge will be disposed.
-To B E ?Qo v1 Deb
w,TM avrFiic.c. R“.oc, b. Stand- by power provisions are needed for all facilities discharging into WS, B,
SA or SB waters as outlined in the regulations.
NO. c. if facility is to dispose of wastewater (discharge or nondischarge method) in
coastal areas applicable to 15 NCAC 2H 0.0400, make sure facility meets
minimum design criteria and buffers as specified in 15 NCAC 2H 0.0400.
d. Flow recorder and totalizer required as specified in the NPDES permit.
e. Plans shall show the 100- year flood elevation. Facilities shall be protected
from the 100- year flood.
141t f. Equalization tank shall be aerated.
Nl� g. Effluent dosing tank, if needed, shall have duplex pumps and high water alarms.
h. Evaluate means of final disposal of wastewater.
i. Check security measures, i.e. fence, light, etc.
j. Facility should provide source of wash down water on site.

j_,
UNION COUNTY PUBLIC WORKS DEPARTMENT
Mike Shalari, Director
'AUG 1 i994
WATER QUALITY
Mr. A. Preston Howard, Jr., P.E.
SECT/ON
Director
North Carolina Department of.Environment,
Health and Natural Resources
Division of Environmental Management
P.O. Box 29353
512 N. Salisbury Street
Raleigh, NC 27626-0535
Re: Authorization
Crooked Creek
Union County,
Dear Mr. Howard:
y 22, 1994
JUL 29 1994
DV. 7 ttiV{RINWENTAL'18 h
e.
DIRECTOR'S OFFICE
to Construct Application #ACB069841
Wastewater Treatment Plant No. 2
North Carolina
Union County was greatly distressed to receive your letter of July
12, 1994 returning the County's application for an Authorization to
Construct an expansion of the Crooked Creek Wastewater Treatment
Plant to 1.3 MGD. The County takes exception to both the
Division's j.ndgement that the current project schedule will not
allow "significant construction" to be accomplished by the permit
expiration date of October 31, 1994, and the further interpretation
by the Division which deems the prd155-16a expansion a "new"
fac .
The purpose of this letter is to demonstrate to the Division that
"more than a token or nominal investment of money or other
resources" (15A NCAC 2H.0103 (14)) has been expended by the County
in pursuit of the proposed expansion, which thereby qualifies the
project for Division review and issuance of an Authorization to
Construct.
We fail to understand how the regulatory requirement to have "begun
significant construction" can be interpreted to require "completion
of significant construction" as stated in your July 12, 1994,
letter. We feel that this proposed expansion of the Crooked Creek
Wastewater Treatment Plant meets the intent of the regulation
regarding beginning significant construction prior to permit
expiration in two ways. Firstly, the treatment plant's initial
construction (completed June 1990) contained substantial and costly
features which were built in anticipation of this proposed
expansion. Secondly, the County is pursuing a construction
schedule for those treatment components required to complete the
expansion to 1.3 MGD which will result in more than a "token or
nominal investment" of County funds prior to the permit expiration
date of October 31, 1994. The following paragraphs discuss
separately these two issues.
P.O. Box 987 . Monroe, North Carolina 28111-0987 . Phone: [phone] . Fax: [phone]

Prior Investments Related to the Plant Expansion
Because the Division issued the County a phased NPDES permit which
reflected an initial flow capacity of 0.65 MGD and a future
permitted capacity of 1.3 MGD, significant effort was expended in
the design and construction of the initial facility to accommodate
the future expansion to 1.3 MGD. The following are some specific
examples of features which 1) currently exist at the treatment
plant, 2) required significant investment by the County to include
in the initial construction, and 3) provide no benefit unless the
treatment plant expansion is allowed.
1) Initial Design and Construction Drawings - Substantial
effort was expended during the initial planning and
design of the treatment plant to insure that the facility
was suitable for expansion to 1.3 MGD. The design
included general arrangement drawings showing the future
facilities, and the process calculations were performed
for the 1.3 MGD flow during the initial engineering in
anticipation of the expansion.
2
3
4
5
6
7
)
)
)
)
)
)
Property Size - The County purchased the treatment plant
site from a private land owner at a substantial cost.
The property purchased included additional areas to
accommodate the expansion of the treatment plant.
Without the expansion, the benefit of this expenditure is
lost.
Perimeter Fencing - The initial construction included
additional fencing to encompass the entire treatment
plant site, including the expansion area.
Oxidation Ditches - The oxidation ditches included longer
rotating weirs to accommodate the future 1.3 MGD design
flow. The base slab of the oxidation ditches included a
sacrificial end cap with water stops and threaded
couplers on the rebar to facilitate expansion.
Clarifier Splitter Manhole - There are currently two
clarifiers at the plant; however, the initial
construction included a 4-way concrete splitter box with
substantial runs of ductile iron pipe stubbed out towards
the two additional clarifiers which are required for the
1.3 MGD expansion.
Tertiary Filters - The filters included a broader
influent channel an 12-inch ductile iron stub outs for
the future expansion.
Chlorine Contact Basin and Cascade Aerator - Splitter
manholes were included prior to each of these basins to
facilitate the expansion. Had the expansion not been
planned, these structures would not be necessary.

8
Sludge Transfer Station - The sludge transfer pumps and
polymer feed system were sized to accommodate the 1.3 MGD
flow.
9) Chemical Feed Systems - The lime storage silo, lime feed
system, chlorine and sulfur dioxide systems all were
sized to accommodate the higher flow. Many of the spare
parts which are necessary for the higher flow were
specified and provided in the initial contract, such as
chlorine injectors.
10) Telemetry Systems - The telemetry system control panel
was oversized in the original contract to allow room for
the additional signals necessary for the plant expansion.
11) Plant Hydraulics - The overall plant hydraulics were
designed and constructed to accommodate the expansion
flows. This impacted structure freeboard and pipe sizes
throughout the plant.
12) Overall Infrastructure - Throughout the initial
development of the treatment plant, the County has
pursued a high quality, durable, and long-lasting
treatment plant which can serve as a core facility within
the County's wastewater treatment infrastructure. This
commitment is reflected in the materials of construction,
administration facility, and ancillary components of the
plant. To limit the flow capacity of the treatment plant
would restrict the County from receiving full benefit of
the facility, and would bring into question the continued
existence of the facility.
The County is , and has been confident that the investment which
has already been made toward the expansion of the Crooked Creek
Treatment Plant in both planning and financial resources clearly
complies with the intent of the State's regulation. However, to
further document our efforts, the following timeline is presented.
Project Timeline
The following is a schedule of key dates regarding the project
which further demonstrates compliance with the regulations
regarding expenditure of more than "token or nominal investment"
prior to the permit expiration date of October 31, 1994.
• June 17, 1994 - Application for Authorization to
Construct received by DEM.
▪ August 20, 1994 - Advertisement for bids published for
treatment plant expansion.

September 15, 1994 - Receive bids.
- Receive Authorization to Construct
from DEM.
September 20, 1994 - Award contract to lowest responsible
responsive bidder.
- County commits approximately two
million dollars toward construction.
At this time, in accordance with
state public financing laws and
contract law, the County will have
begun construction of every part of
the wastewater treatment facility
for 1.3 MGD. This is within the
terms of the permit.
September 30, 1994 - Notice to proceed given to the
contractor.
- Construction begins.
▪ October 31, 1994 - Permit expiration date.
- Construction ongoing.
The County has been working with diligence to expand the Crooked
Creek Treatment Plant to provide the additional capacity which is
so desperately needed. The County has met with your Division's
staff and provided clear correspondence outlining the County's
intent and proposed methods to gain Division approval for this
expansion. In the course of this work, the County has never
identified as a point of concern the issue raised by the Division
in its July 12, 1994 letter, nor, to the County's knowledge, has
the Division expressed concern to the County regarding this issue
during our meetings or through correspondence. We are disappointed
that the Division would make this damaging regulatory
interpretation regarding this critical project, and we request
that the Division reconsider its position in light of the
information we have provided.
Respectfully submitted,
Mike Shalati, Union County
Director of Public Works

State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Environmental Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Director
July 12, 1994
Mr. Mike Shalati
Union County Public Works Department
P.O. Box 987
Monroe, NC 28111
A"'A
a E F-1 N I
Subject: Authorization to Construct Return
Application Number ACB069841
Crooked Creek WWTP #2
Union County
Dear Mr. Shalati:
The Authorization to Constuct (ATC) package to construct additional treatment facilities for a total capacity
of 1.9 MGD is being returned.
Although the current permit allows for a flow increase to 1.3 MGD, the Division of Environmental
Management (DEM) will be sending the facility's draft permit for renewal to public notice shortly limiting
flow to 1.0 MGD in accordance with Division regulations for streams with 7Q10 and 30Q2 flows of zero
[15A NCAC 2B .0206(d)]. As stated previously in Steve Tedder's letter of April 4, 1994, copy attached,
no new or expanding discharges of oxygen -consuming waste are allowed at these locations.
As defined by 15A NCAC 2H .0103(14), facilities that have received an ATC but have not begun
significant construction of wastewater treatment facilites within the current permit are considered "new".
Given the typical 60 to 90 day review and approval period, an ATC would not be issued until mid to late
August at the earliest. Completion of significant construction by the October 31, 1994 expiration date is
highly unlikely. Therefore, since any increase above the existing 1.0 MGD treatment capacity is
considered "new" under this scenario, and since the stream flow prohibits any increase in discharge flow,
the ATC package cannot be accepted.
If you have any questions regarding this application, please contact Mr. Dave Goodrich at 919-733-5083.
Sincerely,
A. Preston Howard, Jr., P.E.
cc: Mooresville Regional Office
Central Files
Pollution Prevention Pays
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone]
An Equal Opportunity Affirmative Action Employer