NC0085812_S20-001 Response to SOC_20210125

Union County Public Works
500 N. Main Street
Suite 600
Union County Monroe, NC 28112
T. 704-296-4212
EST. 1842 www.unioncountync.gov
January 14, 2021 RECEIVED
JAN252021
Mr. Derek Denard NCDEQIDWRINPDES
Water Quality Permitting Section
Division of Water Resources
North Carolina Department of Environmental Quality
1617 Mail Service Center
Raleigh,NC,27699-1617
RE: Special Order by Consent
EMC SOC WQ S20-001
Grassy Branch WWTP
NPDES Permit No.NC0085812
Union County
Dear Mr. Denard:
I received your letter concerning the Grassy Branch Wastewater Treatment Plant(WWTP)Special Order
by Consent(SOC),along with the accompanying SOC,via e-mail on December 31,2020. I was able to
open, view,and save/print the document from the e-mail for review. You requested that I sign and return
copies of the executed SOC so that the Department of Environmental Quality(DEQ)Division of Water
Resources(DWR)could publish notice and solicit public comment on the SOC prior to fmal issuance.
You also noted that I could contact DWR's Mooresville Regional Office or you with any questions.
Union County submitted an application for an SOC for the Grassy Branch WWTP on December 30,
2019. As noted,I received the SOC from the DWR on December 31,2020. Union County staff has
reviewed the proposed SOC and also corresponded with DWR's Mooresville Regional Office staff with
questions concerning the letter and SOC. It is our understanding after County staff conversations with
DWR staff that the SOC accompanying your letter was intended to be a draft for Union County's
consideration and comment,not a fmal version of the SOC ready for signature. Thus,we have reviewed
provided comments on the draft SOC(as noted in this letter below),along with a revised,draft version of
the SOC.
We offer the following comments on the initial SOC draft received:
1. SOC Section 1(b)and 1(d)(ii)—Suggested improvements to collection system
Language has been added to the draft SOC that suggests the County will be responsible for replacing the
collection system in the Grassy Branch sewer shed. Our submitted SOC application addresses the
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National Pollutant Elimination System(NPDES)violations at the Grassy Branch WWTP and the
associated WWTP infrastructure improvements necessary to resolve the NPDES notices of violation.The
I/I rehabilitation efforts described in our SOC application were in the context of reducing influent flow to
the Grassy Branch WWTP which is capacity limited.The County has committed to continued I/I
reduction efforts in the Grassy Branch sewer shed. We do not commit to the replacement of the collection
system as part of this SOC.
2. SOC Section 2(a)—Schedule
One of the milestone activities in the Section 2(a)compliance schedule is use of the"existing chlorine
contact basin for disinfection instead of UV disinfection."The existing chlorine contact basin was
permanently converted to a UV disinfection system in a prior retrofit project. The existing UV
disinfection system is fully functional but cannot be further optimized to treat the flow increase at the
Grassy Branch WWTP.A new UV system is included with the proposed infrastructure improvements.
Our proposed compliance schedule in the SOC application provided the number of months from Notice to
Proceed and an Estimated Date from Notice to Proceed for each scheduled milestone activity. The
schedule provided in Section 2(a)of the draft SOC used the estimated dates from Notice to Proceed
without taking into consideration the number of months required to accomplish each scheduled activity.
We offer the following revisions to the compliance schedule with respect to compliance dates and other
modifications:
Proposed Date
Draft SOC Revision/
Scheduled Activity Due Date Comment
Submit Quarterly Progress Reports Beginning Beginning May 15,
April 15,2021 2021
For Collection System Permit WQCS00054
Ongoing inflow and infiltration(I&I)rehabilitation in the March 2016(MET) On-Going
Grassy Branch basin
June 30,2025 Delete provision.
For NPDES Permit NC0085812:
June 30,2021 Delete provision
Submit contract documents for regulatory approval for July 31,2021 September 30,2022
Grassy Branch WWTP upgrade project
Upon receipt of the required the Division of Water October 31,2022 October 1,2023
Resources permit(s),begin construction of Grassy Branch
WWTP upgrades
Complete construction of the upgrades to the wastewater June 30,2025 June 30,2026
treatment plant and submit a certification of completion
(Engineer's Certification)from a professional engineer
,ats,�,
of � -,
y�1F' 1`. Page 2

Proposed Date
Draft SOC Revision/
Scheduled Activity Due Date Comment
verifying that the construction has been completed.Begin
use of new UV disinfection system.
Attain compliance with NPDES permit final limits June 30,2025 June 30, 2026
3. Draft Section 2(c)and Attachment A—Interim effluent limits
The interim flow limit of 0.120 million gallons per day(mgd)is correctly stated in the effluent limits
table in Section 2(c).However,the draft effluent limitation and monitoring requirements page in
Attachment A of the Draft SOC incorrectly lists the interim flow limit as 0.065 mgd. Please correct
Attachment A to provide an interim flow limit of 0.120 mgd.
The effluent limits table in Section 2(c)lists a winter ammonia limit of 12 mg/L in lieu of our proposed
20 mg/L winter ammonia limit. Our SOC application Attachment B provided a Technical Memorandum,
Crooked Creek Model Application Report for the Grassy Branch WWTP(Tetra Tech, October 2019),that
assessed the impacts of the Grassy Branch WWTP expansion flow for the proposed interim effluent limits
using the calibrated QUAL2K model. Per Attachment B of our SOC application,the model results
demonstrated that assimilative capacity is available for our proposed interim SOC effluent permit limits.
Ammonia toxicity will not be exceeded,and the instream dissolved oxygen standard of 5 mg/L will be
met in all conditions. The County requests a revision to the winter ammonia interim limit to 20 mg/L as
supported by our SOC application.
The effluent limits table in Section 2(c)lists a monthly and weekly average fecal coliform limit of
400/mL and 800/mL,respectively. Our requested fecal coliform limit of 900/mL as a daily maximum is
based on historical data for the Grassy Branch WWTP in conjunction with the process modeling and plant
evaluation. The County would consider a proposal from DWR for tiered interim limit for fecal coliform
during the 5-year compliance schedule until the new UV disinfection system is in service.
4. Section 3(c)—Violations and Penalties
The violation description and stipulated penalty for any reportable Sanitary Sewer Overflow(SSO)
should be removed from the table in Section 3(c). The County did not include any statements pertaining
to SSO violations in our SOC application. Our SOC application documented the County's on-going
inflow and infiltration(I/I)reduction efforts in the Grassy Branch sewer shed as a mechanism for
reducing the influent flow to the WWTP.
The stipulated penalty for failure to comply with the modified effluent limit(third row of table in
Section 3(c))indicates a fine of$5,000 for exceeding a monthly average permit limit. We request that the
stipulated penalty be revised to the standard$1,000 for exceeding a monthly average limit and$500 for
exceeding a daily maximum or weekly average limit.
Wtl,pArk Page 3

5. Increase in final capacity from 0.05 to 0.120 mgd
The draft SOC does not acknowledge our request to increase the Grassy Branch WWTP design capacity
from 0.05 to 0.120 mgd. Our SOC application provides a detailed discussion of the flow issues at the
Grassy Branch WWTP. We acknowledged in our application that more sewer connections were allocated
to the Grassy Branch WWTP than available capacity. The treatment issues and associated NPDES
violations leading to the necessity of an SOC are solely attributed to the increase in influent flow at the
Grassy Branch WWTP. Our proposed infrastructure improvements will resolve the treatment issues due
to the increase in flow. However,the County will not be able to comply with the current effluent flow
limitation of 0.05 mgd after the SOC process is completed. A capacity increase to a maximum month
flow of 0.120 mgd is necessary for the Grassy Branch WWTP to remain in compliance at the end of the
SOC process.
In addition to these comments,please find enclosed proposed revisions to the SOC. County staff
respectfully requests a meeting with DWR to discuss the proposed SOC revisions prior to a revised SOC
being issued for notice publication and solicitation of public comment. Further,per your request,I can
confirm that the County finds it acceptable to receive electronic correspondence relating to this SOC.
Please contact Mr. Andrew Neff at(704)296-4215 or [e-mail] to schedule this
meeting or with any questions you may have regarding this correspondence.
Sincerely,
William M.Watson
County Manager
Attach: SOC revisions
cc:
Cory Basinger,Mooresville Regional Office
Andrew Neff,PE,Union County Public Works,Water and Wastewater Division Director
Bart Farmer,Union County Public Works,Water Reclamation Facilities Superintendent
Jim Struve,PE,Hazen and Sawyer
Mary Sadler,PE,Hazen and Sawyer
2 ��p Page 4

NORTH CAROLINA
ENVIRONMENTAL MANAGEMENT COMMISSION
COUNTY OF UNION
IN THE MATTER OF )
NORTH CAROLINA ) SPECIAL ORDER BY CONSENT
NPDES PERMIT NO.NC0085812 ) EMC SOC WQ S20-001
PERMIT NO.WQCS00054 )
)
HELD BY )
UNION COUNTY )
Pursuant to provisions of North Carolina General Statute(G.S.) 143-215.2 and G.S. 143-215.67,
this Special Order by Consent("SOC")is entered into by Union County,hereinafter referred to as
the County, and the North Carolina Environmental Management Commission,an agency of the
State of North Carolina created by G.S. 143B-282, and hereinafter referred to as the Commission:
1. The County and the Commission hereby stipulate the following:
a. The County holds North Carolina NPDES Permit NC0085812 (the "NPDES Permit")for
operation of an
existing wastewater treatment works and for making an outlet therefrom for the discharge
of treated wastewater to Crooked Creek, Class C waters of the State in the Yadkin-Pee
Dee River Basin(the"Grassy Branch WWTP"). The County also holds Collection System
Permit WQCS00054 for the existing wastewater collection system throughout its utility
system(the "Collection System Permit").-
b. The County has been issued Notices of Violation asserting the County,on certain occasions,
exceeded is u n.,ble to istently comply with -the certain final effluent limits set forth in
the NPDES Permit,including Biochemical Oxygen Demand(BOD),Ammonia Nitrogen,
Total Suspended Solids(TSS), and Fecal Coliform. The Notices of Violation concerning
the County exceeding certain County is unable to ennply with operational requirements as
set forth in the NPDES PermitNPDES Permit NC0085812 are largely due to high levels of
inflow and infiltration entering the County's sewer collection system being treated at the
Grassy Branch WWTP which is capacity limited. The County has also been issued Notices
of Violation asserting the County,on certain occasions,has not complied witha'so holds Noah
r l li t; r System Pe,.„.,it WQCS0005I f r o tion faro isting.,asfewater
»ectien stem but: .,able to ^ siste„tly ply with Condition 1.2 regarding
sanitary sewer overflows(SSOs) as set forth in Collection System Permit WQCS00054._
County agrees to address these issues outlined in the Notices of Violation throughEemple-
_�' re completion of continued I&I abatement efforts ongoing sewer line(force main)
rehabilitation to be conducted in the Grassy Branch basin sanitary sewer basin served by
the Grassy Branch WWTP ("Grassy Branch Basin").
cb. Noncompliance with final effluent limitations is considered constitutinges,causing,and
contributing to pollution of the waters of the State named above. Enforcement actions
concerning noncompliance with final effluent limits with the NPDES Permit and the
Collection System Permit is, and the County is within the jurisdiction of the Commission
as set forth in G.S. Chapter 143, Article 21.

de. The County has secured nt . r'' ' ot` erw secured financing for planning,
design, and construction/repairs of the following:
i. Expansion of New etimprovecl-wastewater treatment and disposal system components
as described in Attachment B which,once constructed and operated,will be sufficient to
adequately provide for capacity to convey and treat wastewater presently being
discharged,to such an extent that the City County will be able to comply with the final
effluent limits and operational requirements as set forth in the NPDES Permit-
Nrni. Funding is available in the Union County Public Works Capital
Improvements Program.

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 2 of 6
ii. Continued 1&I abatement efforts on the ^ new or impfeved wastewater collection
system within the portion of the collection system that collects wastewater in the Grassy
Branch Basin -will attenuate capacity restrictions at the Grassy Branch WWTP. which,enee-
1 rl C l it. nditio t Genditie 1 2 as at f rth i, the Collectie
.Funding for operation
and maintenance is appropriated annually by the Board of County Commissioners.
de. Since this Special Order is by Consent, neither party will file a petition for a
contested case or for judicial review concerning its terms.
2. The County, desiring to comply with the
eNPDES Permit and the Collection System Permit, hereby agrees to do the following:
a. a -Undertake the following activities in accordance with the indicated time schedule:
Proposed Date
Draft SOC Revision/
Scheduled Activity Due Date Comment
Submit Quarterly Progress Reports Beginning Beginning May 15.
\pril_15, 2021 2021
For Collection System Permit WOCS00054
Ongoing inflow and infiltration(l&I) rehabilitation in the March 2016 (MET) On-Going
Grassy Branch basin.
June 30, 2025 Delete provision.
Grassy Brach basin
For NPDES Permit NC0085812:
Begin operation of existing chlorine contact basin for June 30, 2021 Delete provision
disinfection instead f r(7 di in4ct:on until completion of
.-adds t„Gran.,,Branch WWTD
Submit contract documents for regulatory approval fo_i July 31, 2021 September 30, 2022
Grassy Branch W W"1TP upgrade project
Upon receipt of the required the Division of Water October 31.,2))2 October 1, 2023
Resources pennit(s), begin construction of Grassy Branch
WWTP upgrades
Complete construction of the upgrades to the wastewater_ ,l tine 30,2025 June 30,2026
treatment plant and submit a certification of completion
(Engineer's Certification)from a professional engineer
verifying that the construction has been completed. Begin
use of new UV disinfection system.
Attain compliance with NPDES permit final limits June 30, 2025 June 30,2026
-Dote
Submit Quarterly Proress Reports Beginning April 15, 2021
(see details in paragraph 2(b)below.)
1 OCS040-54:

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 3 of 6
March 2016(MET)
Branch Bb.,s;,,
C let „Flow a.,d i,giltra♦:.., /IA1\ rehabilitation in the Grassy
Branch Bbasin June 30, 2025
For.1PULS Putt N((4J c -
Begin operation of existing chlorine contact basin for
disinfectionnstead of r rV disinf ction I „til pletio,, „f June 30, 2021
upgrades to Grassy Branch WWTP.
Branch l77\ITTA , ,,lo., o,.t July 3l, 2021
October 31,2022
C plet. st.-, cti f the s ale t tho st��Y UIt r
• VI
treatment plant Grassy Branch WWTP and submit a certification
t t: (— • r rti t )f �' L June 30, 2025
VI-SVIIT�71'CCLVIT�LT1�C�i�Tn�Cfl1T1 CCCCPO'ITJ-I'�r0'RT�"I„]'TOT
verifying that tho str. ction h .. ba o„ pleted.
Begin use of new UV disinfection system.
Attain compliance with NPDES permit final limits June 30. 2025
b. The County will submit quarterly progress reports detailing the work and activities undertaken
and completed on the upgrades to the collection system under the Collection System Permit in
the Grassy Branch Basin and the NPDES Permit as described in this SOC.The reports are to be
submitted as follows:one copy must be mailed to the Mooresville Regional Office
Supervisor,Division of Water Resources/Water Quality Regional Operations Section,
610 East Center Avenue,Suite 301,Mooresville,NC 28115,and one copy must be mailed
to the Water Quality Permitting Section/NPDES, 1617 Mail Service Center Raleigh,NC
27699-1617.

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 4 of 6
The quarterly reports are due in each respective office no later than the fifteenth(15th)day of
February,May,August and November for the duration of this
OfSOC.
c. The County will comply with all terms and conditions of the NPDES Ppermit except
effluent limits for parameters identified in paragraph 1(ba)above and as set forth in this
paragraph below. See Attachment A for all current monitoring requirements and effluent
limits,including interim effluent limits applicable tethrough the term of this Special-Order-
by-CenseetSOC.The-Ceuety-may-alse-he-r-equired-te-meniter-fer-ether-paremeters,as-
eleemed-eeeessay-the-Direetep,-ie-future-pefmits-er-administFative-letter-s,During the
time in which this SOC is effective,the County shall be required
to comply with the interim effluent limits, rather than the final permit effluent limits,for
Total Suspended Solids(TSS),Biochemical Oxygen Demand(BOD),Ammonia Nitrogen,
and Fecal Coliform as listed in the table below. The final effluent flow limit for the
completed project will be 120,000 gallons/day.
Under this SOC,way the parameters listed below have been modified from the most
current NPDES Permit NC0085812 in effect for Outfall 001.
Permit Limits Interim Limits
Parameters Units j Monthly Weekly Monthly Weekly
Avg. Avg. Avg. Avg.
Flow mgd 0.050 NA 0.120 NA
BOD(s) mg/L 5.0 7.5 30.0 45.0
BOD(w) mg/L 10.0 15.0 30.0 45.0
TSS mg/L 30.0 45.0 100.0 150.0
Ammonia Nitrogen(s) mg/L 2.0 6.0 6.0 18.0
Ammonia Nitrogen(w) mg/L 4.0 12.0 20-l-2.0 32.0
Fecal Coliform #/100 mL 200* 400* NOW**
s= summer(April 1 -October 31); w=winter(November 1 —March 31)
* =geometric mean
**Insert 900 tug/1 daily limit
d. No later than fifteen(15)calendar days after any date identified for accomplishment of any
activity listed in 2(a)above(other than the Quarterly Progress Report Requirement),the
County shall submit to the Water Quality Regional Operations Section Regional
Supervisor for the Division of Water Resources'(DWR)Mooresville Regional Office(the
"Regional Supervisor")written notice of compliance or noncompliance therewith. In the
case of noncompliance,the notice shall include a statement of the reason(s)for
noncompliance,remedial action(s)taken, and a statement identifying the extent to which
subsequent dates or times for accomplishment of listed activities may be affected._
Commission and County agree that if any statement for noncompliance is provided, and
the Regional Supervisor reasonably determines that the statement of reason(s) for
noncompliance, remedial action(s), and subsequent dates or times for accomplishment of
listed activities submitted by the County are reasonable, then the Regional Supervisor
may extend such dates for accomplishment set forth in paragraph 2(a).
e. The County will continue to operate the wastewater treatment plantGrassy Branch
WWTP using commercially reasonable efforts, including the efforts described in this
SOC, to as best as possible te-prevent/minimize any adverse impacts to the surface

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 5 of 6
waters.
3. The County, desiring to comply with the Permits identified in paragraph 1(a) above,hereby
agrees to the following settlement of outstanding civil penalties;through an upfront penalty,
and stipulated penalties:
a. The County has outstanding civil penalty assessments from certain Notices of Violation that
total $6,737.72. As full and final settlement and satisfaction of all alleged violations and
any and all claims or prospective claims that the Commission has or may have for
violations of the NPDES Permit or the Collection System Permit in the Grassy Branch
Basin f NPDES permit., mber NC008581 2 and Collection System

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 6 of 6
Permit WQCS00054 prior to the date the Commission entersiig into this Special
entSOC;(which specifically includes, without limitation, all Notices of
Violations issued, or which may have been issued, for alleged violations of the
NPDES Permit and the Collection System Permit in the Grassy Branch Basin as
described in paragraph 1 above),the County agrees to pay an upfront penalty amount
of$1,362.72, with the remaining amount of
$5,375.00 to be held in abeyance until the successful completion of this SOC. A certified
check in the amount of$1,362.72 must be made payable to the North Carolina
Department of Environmental Quality and forwarded to the Director of DWR by no later
than fifteen(15)days following the date on which this OrelerSOC is approved and
executed by the Commission and received by the County.
b. At the successful conclusion of this SOC,the penalty amount
held in abeyance($5,375.00)will be remitted by the Commission and Department of
Environmental Quality. Should the Special Order by CensentSOC not reach a successful
conclusion, including consideration of any amendments to the SOC or modifications
granted hereunder,the full remaining penalty amount of$5,375.00 will be due
immediately by check payable to the North Carolina Department of Environmental
Quality and forwarded to the Director.
c. The County agrees that unless excused under paragraphs 2(d)or four(4),the County will
pay the Director of DWR,by check payable to the North Carolina Department of
Environmental Quality, stipulated penalties according to the following schedule for
failure to meet the deadlines set out in paragraphs 2(a), 2(b), and 2(d); and interim
effluent limits and monitoring requirements set out in paragraph 2(c) during the term of
this SOC:
Violation Description Stipulated Penalty
• S250 per SSO greater than 1,000 gallons and less than 100,000
Any reportable Sanitary gallons. (to be paid on a monthly basis)
Sewer Overflow (SSO) in • QGnn SSO . ater than 100 001 gallons (to tie id . „
the Grassy Branch Basin
Failure to meet a $500 per day
scheduled date
Failure to comply with $15,000 (monthly average)
the modified effluent —
flow limit
Failure to comply with a • $1,000 for exceeding monthly average(or geometric mean)limit
modified effluent limit • $500 for exceeding weekly average(or geometric mean)limits
(to be paid on a monthly basis).
Monitoring frequency $100 per omitted value per parameter(to be paid on a monthly
violations for modified basis)
parameters
Failure to Submit Status $500 for the first violation;penalty doubles with each subsequent
Reports assessment for late reports
Failure to achieve
compliance with final $5,000 (single penalty)
effluent limits
d. Certified checks are to be made payable to the North Carolina Department of

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 7 of 6
Environmental Quality and forwarded to Director of DWR at 1617 Mail Service
Center,Raleigh,North Carolina 27699-1617.

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 8 of 6
4. The County and the Commission agree that the stipulated penalties are not due if the County
satisfies DWR, as such satisfaction is reasonably determined by DWR,that noncompliance
was caused solely by:
a. An act of God;
b. An act of war;
c. An intentional act or omission of a third party,but this defense shall not be available if
the act or omission is that of an employee or agent of the defendant-County or if the act
or omission occurs in connection with a contractual relationship with the permittee;
d. An extraordinary event beyond the permittee's County's control. Contractor delays or
failure to obtain funding will not be considered as events beyond the perittee'
County's control;or
e. Any combination of the above causes.
Failure within thirty(30) days of receipt of written demand to pay the penalties,or challenge
them by a contested case petition pursuant to G.S. 150B-23,will be grounds for a collection
action, which the Attorney General is hereby authorized to initiate. The only issue in such an
action will be whether the thirty(30)days has elapsed.
5. Noncompliance with the terms of this SOC is subject to
enforcement action in addition to the above stipulations,including injunctive relief pursuant
to G.S. 143-
215.6.C. Noncompliance with the terms of this SOC will not be subject to civil penalties in
addition to the above stipulated penalties.
6. This Special O der by Co sentSOC and any terms or conditions contained herein,hereby
supersede any and all previous Special Orders, Enforcement Compliance Schedule Letters,-
terms, conditions,and limits contained therein issued in connection with the NPDES Ppermit
number NC0085812 and the Collection System Permit(in the Grassy Branch Basin)-
WQC-S00054. In the event of an NPDES Ppermit modification or renewal, any effluent limit
or monitoring requirements contained therein shall supersede those contained in Attachment
A of this SOC, except as modified and contained in paragraph 2(c)
above.
7. This SOC may be amended provided the County has made good
faith efforts to secure funding, complete all construction and achieve compliance within the
dates specified. Such amendment may include, without limitation, modification to the
improvements project described in Attachment B if such modifications are reasonably
determined by County and Commission to be designed to meet the final effluent limits of
set forth inparagraph 2(a),
the NPDES permit and the schedule

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 9 of 6
8. During the term of this Special Order by Ceu entSOC, the County will not be permitted to
accept additional wastewater from any domestic, industrial, or commercial sources within the
Grassy Branch Basin without prior approval from the Mooresville Regional Supervisor and the
Water Quality Permitting Section except for 3 remaining lots in the Smithtiled subdivision not
yet connected to the Grassy Branch system.

Union County—Grassy Branch WWTP
EMC SOC WQ S20-001
Page 10 of 6
9. Failure to meet the scheduled date identified in paragraph 2(a), as may be modified as
described in this SOC, after notice from the Commission and failure to cure by the County
within fifteen (15) days of such notice.,the Commission may terminate this Special Order by
CensentSOC and require the County to comply with the terms and conditions contained in
the permits identified in paragraph 1(a).
10. The County,upon signature of this SOC,will be expected to
comply with all schedule dates,terms,and conditions of this document.
This Special Order by Consent shall expire,S„ntcmber 20. 202 June 30, 2026.
For N Union County:
William M. Watson, County Manager Date
For the North Carolina Environmental Management Commission:
S. Daniel Smith,Director Date
Division of Water Resources

ATTACHMENT A Permit NC0085812
EMC SOC WQ S20-001
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B .0400 et seq., 15A NCAC 02B .0500 et seq.]
Grade II Biological Water Pollution Control System [15A NCAC 08G.0302]
Beginning on the effective date of this permit and lasting until expiration, the Permittee is authorized to
discharge treated wastewater from Outfall 001. Such discharges shall be limited and monitored' by the
Permittee as specified below:
PARAMETER LIMITS MONITORING REQUIREMENTS
Monthly Weekly Daily Measurement Sample Sample
[eDMR Code] Average Average Maximum Frequency Type Location2
Flow [50050] 0.12 i i(1F,:s Continuous Recording Influent or
r�ri* Effluent
BOD,5-day,20°C 3 [C0310] 30.0 mg/I* 45.0 mg/1* Weekly Composite Effluent,
(April 1 —October 31) Influent
BOD,5-day,20°C 3 [CO310] 30.0 mg/1* 45.0 mg/1* Weekly Composite Effluent,
(November 1 —March 31) Influent
3 100.0 m /1* 150.0 m /1* WeeklyComposite Effluent,
Total Suspended Solids [C0530] g g p Influent
(April 1 3 as NOctober 31) [C0610] 6.0 mg/1* 18.0 mg/1* Weekly Composite Effluent
NH3 as N [C0610] 'i1 I is mg/1* 32.0 mg/1* Weekly Composite Effluent
(November 1—March 31)
Dissolved Oxygen [00300] Daily Average>5.0 mg/L Weekly Grab Effluent
Fecal Coliform(geometric mean) 44444 1,),;,}mi., SOO 4 E4 1111y 900 inELl Weekly Grab Effluent
[31616]
Temperature(°C) [00010] Weekly Grab Effluent
Total Residual Chlorine 4,5 [50060] 17 µg/L 2/Week Grab Effluent
pH [00400] >6.0 and<9.0 standard units Weekly Grab Effluent
Mercury 6,Total(as Hg) Monitor and report once during this permit Once per Grab Effluent
Concentration [COMER] cycle(ng/L)using Method 1631E permit cycle
Dissolved Oxygen [00300] Variable 2 Grab U,D
Temperature(°C) [00010] Variable 2 Grab U,D
* SOC Limits are effective beginning on the effective date of the SOC and lasting until the SOC compliance date
June 30, 2025. The SOC shall expire on September 30, 2025.
Footnotes:
1. The permittee shall submit discharge monitoring reports electronically using the Division's eDMR system
[see A. (3)].
2. Sample locations: U-Upstream 50 feet above discharge point, D-Downstream at NC 218 bridge.
Upstream/downstream samples shall be collected 3/Week during June,July, August, September,and Weekly
during the remaining months of the year.
Page 1 of 2

ATTACHMENT A Permit NC0085812
EMC SOC WQ S20-001
Instream monitoring requirements shall be provisionally waived so long as the permittee remains a member of
the Yadkin Pee Dee River Basin Association and the Association continues to function as approved by the
Division and Environmental Management Commission.
3. The monthly average effluent BOD5 and TSS concentrations shall not exceed 15%of the respective influent
value(85%removal).
4. Total Residual Chlorine monitoring is required only if chlorine is added to the effluent.
5. The Division shall consider all effluent TRC values reported below 50 µg/1 to be in compliance with the
permit.However,the Permittee shall continue to record and submit all values reported by a North Carolina
certified laboratory(including field certified),even if these values fall below 50 µg/L.
6. Compliance with this limit shall be determined in accordance with A.(2).
Condition:
• There shall be no discharge of floating solids or visible foam in other than trace amounts.
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ATTACHMENT B
EMC SOC WQ S20-001
Union County—Grassy Branch WWTP Improvements
Brief Project Description
The Grassy Branch WWTP improvements will include implementation and/or construction
of the following items:
• Larger influent pumps.
• A retrofit of the existing aeration basin coarse bubble diffusers to the fine bubble diffuser
equipment.
• One additional package plant secondary treatment train to include volume for flow
equalization.
• New positive displacement blowers serving the existing and new aeration basins.
• An additional secondary clarifier.
• A new cloth disk filter.
• A new UV disinfection system.
• Additional volume for aerobic digestion.
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