NC0041696_Draft Permit_20240109

ROY COOPER �� � ,
Governor if
ELIZABETH S.BISER
Secretary
RICHARD E.ROGERS,JR. NORTH CAROLINA
Dlrnctor Environmental Quality
1/9/2024
Mr. Greg Padgett, Water Resources Director 1
Town of Valdese
PO Box 339
Valdese,North Carolina 28690
Subject: Draft NPDES Permit Modification
Permit NC0041696
Lake Rhodhiss WWTP
Burke County
Grade IV Biological WPCS
SIC Code 4952
Dear Mr. Padgett:
The Division of Water Resources staff has reviewed your July 17, 2023 request for modification of the
Lake Rhodhiss WWTP's NPDES permit to replace the existing chlorine disinfection and dechlorination
system with peracetic acid(PAA)disinfection. The resultant change is the revision of the facility's system
components list as well as the introduction of effluent PAA residual requirements and effluent E. coli
monitoring.
In addition,the Town requested the monitoring frequency for effluent monitoring of BOD5,ammonia,TSS
and fecal coliform be reduced to 2/week based on the 2012 Guidance Regarding the Reduction of
Monitoring Frequencies in NPDES Permits for Exceptionally Performing Facilities. Upon further review
by Division staff, it was determined that the Town is eligible for this monitoring frequency reduction and
the monitoring requirements have been adjusted for BOD5, ammonia, TSS. However, to track the
effectiveness of the conversion of disinfection methods from chlorine to PAA,the reduction in monitoring
frequency for effluent fecal coliform has been delayed.After six(6)consecutive months of daily sampling,
the Town may request a reduction in the monitoring frequency to 2/week sampling for fecal coliform if no
effluent permit limit violations have occurred. Please review this modification carefully to ensure thorough
understanding of the requirements and conditions it contains.
The NPDES standard conditions(Parts II, III, and IV)that are a part of the permit are not included in this
draft document(cover,map,and Part I). The conditions are the same as in your current permit except that
agency and division names have been updated.The latest version is available at https://bit.ly/3k5NFaL and
can be viewed online or downloaded as a PDF file.
Concurrent with this notification the Division is publishing a notice in a newspaper having circulation in
the general Burke County area,soliciting public comments on this draft permit. Please provide any written
comments you may have to the following:NCDEQ/DWR,NPDES Permitting Branch, 1617 Mail Service
Center,Raleigh,NC 27699-1617 no later than 30 days after receipt of this draft permit.
Following the 30-day public comment period,the Division will review all pertinent comments and take
appropriate action prior to issuing a final permit modification. If you have questions concerning this draft
permit,please call me at(919) 707-3609 or by email at [e-mail].
Sincerely, Docusipn.a by:
MFBFCA14FD_
Nick Coco,Pt
NPDES Municipal Permitting Unit
Hardcopy: NPDES Files(pages 2—8 of 15)
Ecopy: US EPA Region 4
DWR/Asheville Regional Office/Water Quality/Daniel Boss
DWR/Public Water Supply
D_E Q N512 orthNorth CarolinaSalisbury
Department of Environmental Quality I Division of Water Resources
Street 11611 Mail Service Center I Raleigh,North Carolina 27699-1611
Now,. ,N, 919.707 9000
Deparlarrt at__t_._Ul01rNv

Permit NC004 1696
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge, are hereby revoked.As of this
permit issuance, any previously issued permit bearing this number is no longer effective. Therefore, the exclusive
authorityto operate and discharge from this facilityarises under the permit conditions, requirements, terms, and
provisions included herein.
Town of Valdese
is hereby authorized to
1. Continue to operate a 7.5 MGD capacity wastewater treatment facility with an approved
authorization to discharge 3.5 MGD with the following components:
➢ Screening and grit removal structure/vortex grit collector.
➢ Influent pump station
➢ Primary clarifiers
➢ Aeration basins
➢ Secondary clarifiers
> Peracetic Acid (PAA) contact basin
➢ Gravity sludge thickeners
> Centrifuges
➢ Dewatering structure
➢ Residuals composting operation
> SCADA system
2. Discharge treated wastewater into the Lake Rhodhiss (Catawba River),classified WS-IV, B,
and CA waters,through outfall 001. The location is specified on the attached map.
Upon reaching a calendar year annual average daily flow equal or greater than 2.8 MGD (80% of 3.5
MGD),or upon receiving an Authorization to Construct from the Division of Water Resources to
expand and operate the facility to 7.5 MGD,the Permittee is required to submit a written notification
to NC DEQ confirming that compliance with the 7.5 MGD limitation page is now in effect. Provided
that the facility can comply with the issued permit limits.
Upon receiving an Authorization to Construct from the Division of Water Resources to expand and
operate the facility to 10.5 MGD, the Permittee is required to submit a written notification to NC DEQ
confirming compliance with the 10.5 MGD limitation page.
Modified Month xx, 2024
Modification Effective Month xx, 2024
Page 2 of 15 Michael J. Montebello,
NPDES Permitting Branch Chief
Division of Water Resources

Permit NC0041696
PART I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (3.5 MGD) - [15A
NCAC 02B .0400 ET SEQ., 02B .0500 ET SEQ.] GRADE IV BIOLOGICAL WATER POLLUTION
CONTROL SYSTEM [15A NCAC 08G .0302]
a) Beginning on the effective date of this permit and lasting until this facility reaches an annual
average daily flow equal to or greater than 2.8 MGD(80% of 3.5 MGD) or expiration, the
Permittee is authorized to discharge from outfall 001,treated municipal and pretreated
industrial wastewater. Such discharges shall be limited and monitored) by the Permittee as
specified below:
EFFLUENT LIMITS MONITORING REQUIREMENTS
PARAMETER Monthly Weekly Daily Measurement Sample Sample
Average Average Maximum Frequency Type Location2
Flow 50050 3.5 MGD Continuous Recording I or E
BOD5(20°C)3 C0310 30.0 mg/L 45.0 mg/L 2/week4 Composite I and E
Total Suspended C0530 30.0 mg/L 45.0 mg/L 2/week4 Composite I and E
Solids3
Ammonia(NH3 as N) C0610 Monitor and Report 2/week4 Composite E
Dissolved Oxygen, 00300 Daily Average >_ 5 mg/L Daily Grab E
mg/L
Temperature,°C 00010 Monitor and Report Daily Grab E
Conductivity, 00094 Monitor and Report Daily Grab E
µmhos/cm
Fecal Coliform 31616 200/100 mL 400/100 mL Daily4.5 Grab E
(Geometric Mean)
E.coli,MPN6 51040 Monitor and Report Weekly Grab E
pH 00400 Between 6.0 and 9.0 standard units Daily Grab E
Total Residual 50060 28 pg/L Daily Grab E
Chlorine(TRC)
PM Residuals 51674 Monitor and Report Daily Grab E
Total Hardness9[as 00900 Monitor and Report Quarterly Composite E
CaCO3],mg/L
Total Hardness9[as 00900 Monitor and Report Quarterly Grab U
CaCO3],mg/L
Total Nitrogen 10
(TN),mg/L C0600 Monitor and Report Monthly Composite E
(NO2+NO3+TKN)
Total Phosphorus C0665 Monitor and Report Monthly Composite E
(TP), mg/L
Dissolved Oxygen, 00300 Monitor and Report Variable 11.12 Grab U and D
mg/L
Temperature,°C 00010 Monitor and Report Variable 11'12 Grab U and D
Conductivity, 00094 Monitor and Report Variable 11'12 Grab U and D
µmhos/cm
ne3 Effluent PollutantSca NC01 Monitor and Report Footnote 13 Footnote 13 E
Chronic Toxicity14 TGP3B See Footnote 14 Quarterly Composite E
Footnotes:
1. The Permittee shall submit discharge monitoring reports electronically using NC DWR's eDMR application
system. See Special Condition A. (8).
2. Sample Location:E-Effluent,I-Influent,U-Upstream at least 100 feet from the outfall,D-Downstream,I
mile from the outfall,at North Carolina State Road(NCSR)1001.
Modified Month xx, 2024
Modification Effective Month xx, 2024
Page 3 of 15 Michael J. Montebello,
NPDES Permitting Branch Chief
Division of Water Resources

Permit NC004 1696
3. The monthly average effluent BOD5 and total suspended solids concentrations shall not exceed 15%of the
respective influent value(85%removal).
4. Twice per week sampling must occur on any two non-consecutive days during the calendar week.
5. After six(6)consecutive months of daily sampling,the Permittee may request a reduction in the monitoring
frequency to twice per week sampling for Fecal conform if no effluent permit limit violations have occurred.
6. E.coli shall be measured using either Method IDEXX Colilert®or IDEXX Colilert®-18.
7. The facility shall monitor TRC when using chlorination for disinfection.The Division shall consider all effluent
total residual chlorine 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/1.
8. PAA residual shall be measured using either Hach Method 10297(DPD Instrumental Method)or CHEMetrics Kit
K-7913(DPD Instrumental Method).Use of any other test method for PAA residual will require prior Division
approval.
9. Effluent Total Hardness sampling shall be performed in conjunction with testing for hardness-dependent metals
(cadmium,copper,lead,nickel,silver,and zinc). The Permittee shall sample instream hardness upstream of the
facility's discharge.The sample shall be representative of the hardness in the receiving stream.
10. For a given wastewater sample,total nitrogen(TN)=TKN+NO3-N+NO2-N,where TKN is total kjeldahl
nitrogen,and NO3-N and NO2-N are nitrate and nitrite nitrogen,respectively.
11. Variable monitoring frequency is defined as follows:samples collected three times per week during June 1
through September 30 and once per week October 1 through May 31.
12. If the Permittee is a member of a monitoring coalition program,sampling may be waived as long as the
monitoring coalition agrees to sample at a minimum frequency of quarterly,and the Permittee has obtained
approval from DWR-NPDES Permitting Unit that the location being monitored by the Coalition and the sampling
is representative of the receiving stream for this discharge.The Permittee is responsible for submitting test results
with its permit renewal application package.If Coalition membership is canceled or the Coalition terminates
sampling at the approved station,the Permittee will immediately notify the Division and resume sampling for
upstream of its discharge.
13. The Permittee shall perform three Effluent Pollutant Scans during the term of this permit.See Special Condition
A.(6).
14. Chronic Toxicity(Ceriodaphnia)P/F 0 2.4%,January,April,July,October.See Special Condition A.(4).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Modified Month xx, 2024
Modification Effective Month xx, 2024
Page 4 of 15 Michael J.Montebello,
NPDES Permitting Branch Chief
Division of Water Resources

Permit NC0041696
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (7.5 MGD) [15A
NCAC 02B .0400 ET SEQ.,02B .0500 ET SEQ.] GRADE IV BIOLOGICAL WATER POLLUTION
CONTROL SYSTEM [15A NCAC 08G .0302]
a) Beginning when this facility reaches an annual average daily flow equal to or greater than 2.8
MGD and lasting until expiration or expansion to 10.5 MGD,the Permittee is authorized to
discharge from outfall 001,treated municipal and pretreated industrial wastewater. Such
discharges shall be limited and monitored.' by the Permittee as specified below:
EFFLUENT LIMITS MONITORING REQUIREMENTS
PARAMETER Monthly Weekly Daily Measurement Sample Sample
Average Average Maximum Frequency Type Location2
Flow 50050 7.5 MGD Continuous Recording I or E
Total Monthly Flow 82220 Monitor and Report Continuous Calculated I or E
BODs(20°C)3 C0310 30.0 mg/L 45.0 mg/L Daily4 Composite I and E
Total Suspended CO530 30.0 mg/L 45.0 mg/L Daily4 Composite I and E
Solids3
Ammonia(NH3 as N) C0610 16.0 mg/L 35.0 mg/L Daily4 Composite E
Dissolved Oxygen, 00300 Daily Average >_ 5 mg/L Daily Grab E
1 mg/L
Temperature, °C 00010 Monitor and Report Daily Grab E
Conductivity, 00094 Monitor and Report Daily Grab E
µmhos/cm
Fecal Coliform 31616 200/100 mL 400/100 mL Daily4 Grab E
(Geometric Mean)
E. coli, MPN5 51040 Monitor and Report Weekly Grab E
pH 00400 Between 6.0 and 9.0 standard units Daily Grab E
Total Residual Chlorine(TRC)6 50060 28 pg/L Daily Grab E
I' 51674 1.8 mg/L Daily
Residua g/ Grab E
Total Hardness 8 [as 00900 Monitor and Report Quarterly Composite E
CaCO3],mg/L
Total Hardness8[as 00900 Monitor and Report Quarterly Grab U
CaCO3],mg/L
Total Nitrogen 9(TN),
mg/L C0600 Monitor and Report Monthly Composite E
(NO2+NO3+TKN)
Total Phosphorus CO665 Monitor and Report Monthly Composite E
(TP),mg/L
TN Load10 QY600 146,659 lb/year Annual Calculated E
TP Load10 QY665 33,200 lb/year Annual Calculated E
Dissolved Oxygen, 00300 Monitor and Report Variable 1132 Grab U and D
mg/L
Temperature,°C 00010 Monitor and Report Variable 11•12 Grab U and D
Conductivity, 00094 Monitor and Report Variable 11.12 Grab U and D
µmhos/cm
Efflu
ent
Went Pollutant NC01 Monitor and Report Footnote 13 Footnote 13 E
Chronic Toxicityl4 TGP3B See Footnote 134 Quarterly Composite E
Footnotes on next page. Modified Month xx, 2024
Modification Effective Month xx, 2024
Page 5 of 15 Michael J. Montebello,
NPDES Permitting Branch Chief
Division of Water Resources

Permit NC0041696
Footnotes:
1. The Permittee shall submit discharge monitoring reports electronically using NC DWR's eDMR application
system. See Special Condition A. (8).
2. Sample Location:E-Effluent,I-Influent,U-Upstream at least 100 feet from the outfall,D-Downstream,1
mile from the outfall,at North Carolina State Road(NCSR)1001.
3. The monthly average effluent BOD5 and total suspended solids concentrations shall not exceed 15%of the
respective influent value(85%removal).
4. Once the 7.5 MGD limits page has been placed into effect and after six(6)consecutive months of daily sampling,
the Permittee may request a reduction in the monitoring frequency to twice per week sampling for any of the four
parameters(BOD5,TSS,NH3-N and Fecal coliform)for which no effluent permit limit violations have occurred.
Twice per week sampling must occur on any two non-consecutive days during the calendar week.
5. E.coli shall be measured using either Method IDEXX Colilert®or IDEXX Colilert®-18.
6. The facility shall monitor TRC when using chlorination for disinfection.The Division shall consider all effluent
total residual chlorine 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.
7. PAA residual shall be measured using either Hach Method 10297(DPD Instrumental Method)or CHEMetrics Kit
K-7913(DPD Instrumental Method).Use of any other test method for PAA residual will require prior Division
approval.
8. Effluent Total Hardness sampling shall be performed in conjunction with testing for hardness-dependent metals
(cadmium,copper,lead,nickel,silver,and zinc). The Permittee shall sample instr•;`p s>. ardness upstream of the
facility's discharge.The sample shall be representative of the hardness'in the receiv` •am.
9. For a given wastewater sample,total nitrogen(TN)=TKN+NO3-N+NO2-N,where total kjeldahl
nitrogen,and NO3-N and NO2-N are nitrate and nitrite nitrogen,respectively.
10. TN and TP load is the mass of total nitrogen and total phosphorous discharged in a given period of time.See
special condition A.(5).
11. Variable monitoring frequency is defined as follows:samples collected three times per week during June 1
through September 30 and once per week October 1 through May 31.
12. If the Permittee is a member of a monitoring coalition program,sampling may be waived as long as the
monitoring coalition agrees to sample at a minimum frequency of quarterly,and the Permittee has obtained
approval from DWR-NPDES Permitting Unit that the location being monitored by the Coalition and the sampling
is representative of the receiving stream for this discharge.The Permittee is responsible for submitting test results
with its permit renewal application package.If Coalition membership is canceled or the Coalition terminates
sampling at the approved station,the Permittee will immediately notify the Division and resume sampling for
upstream of its discharge.
13. The Permittee shall perform three Effluent Pollutant Scans during the term of this permit.See Special Condition
A.(6).
14. Chronic Toxicity(Ceriodaphnia)P/F®4.9%,January,April,July,October.See Special Condition A.(4).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Modified Month xx, 2024
Modification Effective Month xx, 2024
Page 6 of 15 Michael J.Montebello,
NPDES Permitting Branch Chief
Division of Water Resources

Permit NC0041696
A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (10.5 MGD) [15A
NCAC 02B .0400 ET SEQ.,02B .0500 ET SEQ.] GRADE IV BIOLOGICAL WATER POLLUTION
CONTROL SYSTEM [15A NCAC 08G .0302]
a) Beginning upon expansion to 10.5 MGD and lasting until expiration. The Permittee is
authorized to discharge from outfall 001 treated municipal and pretreated industrial
wastewater. Such discharges shall be limited and monitored)by the Permittee as specified
below:
EFFLUENT LIMITS MONITORING REQUIREMENTS
PARAMETER Monthly Weekly Daily Measurement Sample Sample
Average Average Maximum Frequency Type Location2
Flow 50050 10.5 MGD Continuous Recording I or E
Total Monthly Flow 82220 Monitor and Report Continuous Calculated I or E
BOD5(20°C)3 C0310 15.0 mg/L 22.5 mg/L Daily4 Composite I and E
Total Suspended Solids3 C0530 30.0 mg/L 45.0 mg/L Daily4 Composite I and E
Ammonia(NH3 as N) C0610 4.0 mg/L 12.0 mg/L Daily4 Composite E
Dissolved Oxygen, 00300 Daily Average >_ 5 mg/L Daily Grab E
mg/L
Temperature, °C 00010 Monitor and Report Daily Grab E
Conductivity, 00094 Monitor and Report Daily Grab E
µmho/cm
Fecal Coliform 31616 200/100 mL 400/100 mL Daily4 Grab E
(Geometric Mean)
E.coli,MPN5 51040 Monitor and Report Weekly Grab E
pH 00400 Between 6.0 and 9.0 standard units Daily Grab E
Total Residual 50060 28 pg/L Daily Grab E
Chlorine(TRC)6
PM Residual' 51674 1.3 mg/L Daily Grab E
Total Hardness s[as 00900 Monitor and Report Quarterly Composite E
CaCO3],mg/L
Total Hardness$[as 00900 Monitor and Report Quarterly Grab U
CaCO3],mg/L
total kjeldahl 00625 Monitor and Report Monthly Composite E
nitrogen(TKN)
NO2 +NO3 00630 Monitor and Report Monthly Composite E
Total Nitrogen 9
(TN),mg/L C0600 Monitor and Report Monthly Composite E
(NO2+NO3+TKN)
Total Phosphorus C0665 Monitor and Report Monthly Composite E
(TP),mg/L
TN Load 10 QY600 146,659 lb/year Annual Calculated E
TP Load 10 QY665 33,200 lb/year Annual Calculated E
Table continues on next page. Modified Month xx, 2024
Mod f cation Effective Month xx, 2024
Page 7 of 15 Michael J. Montebello,
NPDES Permitting Branch Chief
Division of Water Resources

Permit NC0041696
EFFLUENT LIMITS MONITORING REQUIREMENTS
PARAMETER Monthly Weekly Daily Measurement Sample Sample
Average Average Maximum Frequency Type Location2
Dissolved Oxygen, 00300 Monitor and Report Variable 11'12 Grab U and D
mg/L
Temperature,°C 00010 Monitor and Report Variable 11'12 Grab U and D
Conductivity, 00094 Monitor and Report Variable"•12 Grab U and D
µmho/cm
Effluent Pollutant NC01 Monitor and Report Footnote 13 Footnote 13 E
Chronic Toxidty14 TGP3B See Footnote 14 Quarterly Composite E
Footnotes:
1. The Permittee shall submit discharge monitoring reports electronically using NC DWR's eDMR application
system. See Special Condition A.(8).
2. Sample Location:E-Effluent,I-Influent,U-Upstream at least 100 feet from the outfall,D-Downstream,1
mile from the outfall,at North Carolina State Road(NCSR) 1001.
3. The monthly average effluent BOD5 and total suspended solids concentrations shall not exceed 15%of the
respective influent value(85 %removal).
4. Once the 10.5 MGD limits page has been placed into effect and after six(6)consecutive months of daily sampling,
the Permittee may request a reduction in the monitoring frequency to twice per week sampling for any of the four
parameters(BOD5,TSS,NH3-N and Fecal coliform)for which no effluent permit limit violations have occurred.
Twice per week sampling must occur on any two non-consecutive days during the calendar week.
5. E.coli shall be measured using either Method IDEXX Colilert®or IDEXX Colilert®-18.
6. The facility shall monitor TRC when using chlorination for disinfection.The Division shall consider all effluent
total residual chlorine values reported below 50 µg/1 to he 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.
7. PAA residual shall be measured using either Hach Method 10297(DPD Instrumental Method)or CHEMetrics Kit
K-7913(DPD Instrumental Method).Use of any other test method for PAA residual will require prior Division
approval.
8. Effluent Total Hardness sampling shall be performed in conjunction with testing for hardness-dependent metals
(cadmium,copper,lead,nickel,silver,and zinc). The Permittee shall sample instream hardness upstream of the
facility's discharge.The sample shall be representative of the hardness in the receiving stream.
9. For a given wastewater sample,total nitrogen(TN)=TKN+NO3-N+NOrN,where TKN is total kjeldahl
nitrogen,and NO3-N and NOrN are nitrate and nitrite nitrogen,respectively.
10. TN and TP load is the mass of total nitrogen and total phosphorous discharged in a given period of time.See
special condition A. (5).
11. Variable monitoring frequency is defined as follows:samples collected three times per week during June 1
through September 30 and once per week October 1 through May 31.
12. If the Permittee is a member of a monitoring coalition program,sampling may be waived as long as the
monitoring coalition agrees to sample at a minimum frequency of quarterly,and the Permittee has obtained
approval from DWR-NPDES Permitting Unit that the location being monitored by the Coalition and the sampling
is representative of the receiving stream for this discharge.The Permittee is responsible for submitting test results
with its permit renewal application package.If Coalition membership is canceled or the Coalition terminates
sampling at the approved station,the Permittee will immediately notify the Division and resume sampling for
upstream of its discharge.
13. The Permittee shall perform three Effluent Pollutant Scans during the term of this permit.See Special Condition
A.(6).
14. Chronic Toxicity(Ceriodaphnia)P/F®6.7%,January,April,July,October.See Special Condition A.(4).
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Modified Month xx, 2024
Modification Effective Month xx, 2024
Page 8 of 15 Michael J.Montebello,
NPDES Permitting Branch Chief
Division of Water Resources