NC0044440_Fact Sheet_20170717

DEPARTMENT OF ENVIRIONMENTAL QUALITY / DIVISION OF WATER RESOURCES
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
City of Cherryville WWTP
NCO044440
I. SUMMARY
The City of Cherryville is requesting renewal of the Cherryville WWTP NPDES Permit. The facility is a major
municipal treatment plant with a design capacity of 2.0 MGD. The plant located in Gaston County serves an
estimated population of 5700. The average daily flow rate ranged from 0.46 MGD in 2012 to 0.57 MGD in 2014.
The Cherryville WWTP consists of bar screen, grit chamber, oxidation ditches, clarifiers, chlorine contact
chamber, cascade aeration system, sludge holding tank and sludge storage lagoon. The treated wastewater is
discharged to the Indian Creek in the Catawba River Basin. The city has a separate sewer system and it is
collecting 100% domestic wastewater.
II. RECEIVING STREAM
The Indian Creek in Catawba River Basin is classified as C waters in South Fork Catawba watershed, HUC
03050102. It is in sub -basin 03-08-35 and not listed for any impairment in 303(d) list published in 2016.
III. DATA REVIEW AND VERIFICATION OF EXISTING CONDITIONS
A. DMR Review
DMRs were reviewed for the period of January, 2012 till December, 2016. The effluent data are summarized in
Table 1.
Table 1. Data Summary
Parameter
Facility Information
Average
Applicant/Facility Name:
City of Cherryville Wastewater Treatment Plant
Applicant Address:
116 South Mountain Street, Cherryville, NC 28021
Facility Address:
736 Tot Dellinger Road, Cherryville, NC 28021
Permitted Flow:
2.0 MGD
mg/1
Type of Waste:
100 %Domestic
< 2
Classification:
III
9.41
Permit Status:
Renewal
NH3N
County
Gaston
35
0.0
Miscellaneous
mg/1
Receiving Stream:
Indian Creek Drainage Basin
Catawba
Stream Classification:
C Sub -basin:
03-08-35
303(d) Listed?
No HUC:
03050102
Drainage Area (miz):
46.4 State Grid / USGS Quad:
F13NE / Lincolnton W, NC
Summer 7Q10 (cfs)
6.1 Latitude:
350 25' 02" N
Winter 7Q10 (cfs)
16 Longitude:
810 21' 44" W
30Q2 (cfs)
- Regional Office:
Mooresville
Average Flow (cfs):
58 Permit Writer:
Trupti Desai
IWC (%):
34 Date:
4/4/2017
I. SUMMARY
The City of Cherryville is requesting renewal of the Cherryville WWTP NPDES Permit. The facility is a major
municipal treatment plant with a design capacity of 2.0 MGD. The plant located in Gaston County serves an
estimated population of 5700. The average daily flow rate ranged from 0.46 MGD in 2012 to 0.57 MGD in 2014.
The Cherryville WWTP consists of bar screen, grit chamber, oxidation ditches, clarifiers, chlorine contact
chamber, cascade aeration system, sludge holding tank and sludge storage lagoon. The treated wastewater is
discharged to the Indian Creek in the Catawba River Basin. The city has a separate sewer system and it is
collecting 100% domestic wastewater.
II. RECEIVING STREAM
The Indian Creek in Catawba River Basin is classified as C waters in South Fork Catawba watershed, HUC
03050102. It is in sub -basin 03-08-35 and not listed for any impairment in 303(d) list published in 2016.
III. DATA REVIEW AND VERIFICATION OF EXISTING CONDITIONS
A. DMR Review
DMRs were reviewed for the period of January, 2012 till December, 2016. The effluent data are summarized in
Table 1.
Table 1. Data Summary
Parameter
Units
Average
Max
Min
Flow
MGD
0.54
1.53
0.12
BOD
mg/1
5.62
56
< 2
DO
mg/1
9.41
13.9
6.1
NH3N
mg/1
1.45
35
0.0
TSS
mg/1
5.32
75
0.0
PH
S.U.
6.61
7.8
6
Page 1 of 4

Parameter
Units
Average
Max
Min
Temperature
°C
17.64
29
6
TRC
µg/1
19.78
78
0.0
TN
mg/1
8.03
59
0.42
TP
mg/l
2.30
7
0.23
Fecal Coliform
#/100 ml
45
2420
0.0
Copper
µg/1
6.69
11
< 5
Cyanide
µg/1
< 0.01
< 0.01
0.0
Zinc
1
0.048
0.082
< 0.02
B. Compliance History
The compliance history from January, 2012 to December, 2016 was reviewed. The facility received three
notices of violations (NOV) during this period. The weekly geometric mean of fecal coliform exceeded the
permit limit in February, 2012 and an enforcement case was opened for this violation in July, 2012. The facility
also received a NOV in February, 2015 for exceeding weekly geometrical mean for fecal coliform.
Compliance inspections were conducted at the facility in January, 2012 and December, 2014 by the Mooresville
Regional Office. The facility was reported non-compliant with the requirements of the NPDES permit in both
inspection reports. The regional staff reported issues with mechanical bar screens and discrepancies in data
reported on DMRs in 2012. During the compliance inspection in 2014, the Mooresville regional staff again
reported compliance issues with bar screen which was rusted and not operational for years. The compliance
inspection report in 2014 also reported that all pumps in influent pump station were not operable.
C. Mercury Evaluation
The permittee is required to monitor mercury as a part of priority pollutant analysis (PPA) using 1631E EPA
method. However, the permittee used method 245.1 for the mercury analysis. As a result, mercury evaluation
was not conducted as per TMDL guidance due to lack of low level mercury data. The permittee has been
informed to use this method for mercury evaluation in future PPAs to have data for mercury evaluation. Since
the facility is currently treating the domestic wastewater only, sources of mercury in the wastewater will be
limited and the concentration of mercury in the treated effluent will not be affecting the water quality standards
of the Indian Creek. Effluent limitation and monitoring requirements are not added for this parameter at this
time.
D. Reasonable Potential Analysis (RPA)
With the approval of Triennial Review (2007-2014) of the NC Water Quality Standard (WQS) by the NC
Environmental Management Committee (EMC) in 2014 and US -EPA (with some exclusions) on April 6,
2016, NPDES Permitting Unit of the NC Division of Water Resources is required to implement the new
dissolved metal standards in all permits public noticed after April 6, 2016.
A reasonable potential analysis using the updated NC WQS was conducted on effluent toxicant data collected
between January, 2012 and December, 2016. Based on this analysis, the following permitting actions are
proposed for this permit:
• Monitoring Only. Copper will receive a monitor -only requirement since it did not demonstrate
reasonable potential to exceed applicable water quality standards/criteria, but the maximum predicted
concentration was >50% of the allowable concentration.
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since they did
not demonstrate reasonable potential to exceed applicable water quality standards/criteria and the
maximum predicted concentration was <50% of the allowable concentration: Cyanide and Zinc.
A spreadsheet of the RPA results is attached to this Fact Sheet.
Page 2 of 4

E. Priority Pollutant Analysis
The facility had performed three priority pollutant analysis and their results were included in the permit renewal
application. Copper, zinc and nickel level were found above the detection level in these PPAs. Reasonable
potential analysis has already been conducted for copper and zinc using the data from DMRs. (Please see D.
Reasonable Potential Analysis for more details). Nickel was considered as a non-detected parameter due to
limited data set (n<9) and just one incidence of detection below the water quality standard. All other priority
pollutants were below detection level.
F. Aquatic Toxicity Testing
Permit holder is required to perform quarterly Whole Effluent Toxicity (WET) test using Ceroidaphnia
Dubia at the effluent concentration of 34%. Total 18 WET tests were conducted from January, 2012 to
December 2016. The facility had passed 17 out of 18 tests. It failed the test conducted in December, 2013
and received a NOV in February, 2014 for this violation. However, it passed two WET tests conducted
at 68% effluent concentration in January and February, 2014. The facility also passed 4 second species
aquatic toxicity tests.
G. Instream Monitoring
The permittee conducts instream monitoring for temperature and dissolved oxygen at designated points
upstream and downstream of outfall 001 in the Indian Creek. The upstream and downstream sample results
from January 2012 to December, 2017 were reviewed and compared to evaluate the impact of the effluent on the
water quality of the Indian Creek. The dissolved oxygen level remained above 6.5 mg/l throughout the year.
Discharge from the facility did not have any impact on DO or temperature of the stream. The facility will
continue instream monitoring requirements as defined in the permit.
IV. COMPLIANCE SCHEDULE
The permittee is required to limit ammonia nitrogen concentration in the effluent according to an updated
NPDES permitting guidance for NPDES Implementation of Ammonia Criteria. The new limits for
summer and winter were calculated using a waste load allocation model. The evaluation uses ammonia
criteria of 1.0 mg/1 for summer and 1.8 mg/l for winter and assumes background concentration of 0.22
mg/l. These limits were discussed with the permittee and a schedule was prepared to achieve compliance
with ammonia nitrogen by May 1, 2020. (See condition A. (5)). Interim effluent limitation and
monitoring requirements were added in the permit from the period beginning on the effective date of
permit and lasting till April 30, 2020. (See conditions A. (2) and A. (3))
IV. LIMITS AND MONITORING REQUIREMENTS
Current conditions, as well as the basis for the limits are summarized in Table 3.
Table 3. Current Conditions and Proposed Changes
Page 3 of 4
Current Limit/Condition
Change
from
Parameter
Previous
Basis for Condition/Change
Monthly
Weekly
Daily
Average
Average
Maximum
Permit
Flow
2.00 MGD
No Change
15A 2B .0505
BOD, 5 -day, 20°
30.0 mg/l
45.0 mg/l
No Change
Secondary treatment standards/40
CFR 133 / 15A 2B .0406
TSS
30.0 mg/l
45.0 mg/1
No Change
Secondary treatment standards/40
CFR 133 / 15A 2B .0406
N113 -N
17.0 mg/l
35.0 mg/l
2.5 mg/l
(April 1 — October 31)
Monthly
Ave. and
7.5 mg/l
Based on a waste load allocation
Weekly
and updated guidance on NPDES
Ave. limit
implementation of Ammonia
criteria
NH3-N
Monitoring only
10 mg/l
(Nov. 1 — March 31)
Monthly
Ave and 30
Page 3 of 4

VI. OTHER PROPOSED CHANGES
To meet new federal regulations for electronic reporting, Special Condition A. (6) has been added describing
requirements for submittal of electronic DMRs.
VII. PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice: 4/4/2017
Permit Scheduled to Issue (tentative): 5/29/2017
VI. STATE CONTACT INFORMATION
If you have any questions on any of the above information or on the attached permit, please contact
Trupti Desai at [phone] or [e-mail].
Copies of the following are attached to provide further information on the permit development:
• Draft permit
• Reasonable Potential Analysis
• Hardness dependent metals implementation fact sheet
NPDES Recommendation by -
Signature: 14_ Date: 4/42017
Page 4 of 4
mg/l
Weekly
Ave. limit
DO
6 mg/1
No Change
For protection of water quality
Fecal Coliform
200/100 ml
400/100ml
No Change
State WQ standards, 15A 2B .0200
Geometric mean)
H
Between 6.0 and 9.0 S.U.
No Chane
State WQ standards, 15A 2B .0200
Total Residual Chlorine
28 gg/l
No Change
Maximum daily limit to protect
acute toxicity
Total Nitrogen/Total
Monitoring only
No Change
15A 02B .0508
Phosphorus
Total Copper
Monitoring only
No Chane
Based on RPA results
Total Zinc and Cyanide
Monitoring only
Removed
Based on RPA results
monitoring
Hardness —Total as
No Monitoring
Added
Revised water quality standards
[CaCO3 or (Ca + Mg)]
quarterly
and EPA's guidelines on hardness
monitoring
dependent metals
of effluent
and
upstream
hardness
Effluent Pollutant Scan
3 Times during thepen-nit cycle
No Chane
40 CFR 122
VI. OTHER PROPOSED CHANGES
To meet new federal regulations for electronic reporting, Special Condition A. (6) has been added describing
requirements for submittal of electronic DMRs.
VII. PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice: 4/4/2017
Permit Scheduled to Issue (tentative): 5/29/2017
VI. STATE CONTACT INFORMATION
If you have any questions on any of the above information or on the attached permit, please contact
Trupti Desai at [phone] or [e-mail].
Copies of the following are attached to provide further information on the permit development:
• Draft permit
• Reasonable Potential Analysis
• Hardness dependent metals implementation fact sheet
NPDES Recommendation by -
Signature: 14_ Date: 4/42017
Page 4 of 4