NC0020737_Fact Sheet_20140708

DENR/DWR
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NCO020737
Facility Information
Applicant Facility Name: City of Kings Mountain Pilot Creek WWTP
Applicant Address: P.O. Box 429; Kings Mountain, North Carolina 28086
Facility Address: Off US Route 74; Kings Mountain, North Carolina 28086
Permitted Flow 6.0 MGD
Type of Waste: Domestic and industrial with pretreatment program
Facility/Permit Status: Class IV Active; Renewal
County: Cleveland Count
Miscellaneous
Receiving Stream: Buffalo Creek Regional Office: Mooresville MRO
Stream Classification: C State Grid / USGS F13SW
Quad:
303(d) Listed? No Permit Writer: Sergei Chernikov,
Ph.D.
Subbasin: 03-08-05 Date: July 8, 2014
Drainage Area (mi2): 116
Summer 7Q 10 cfs 19
Winter 7Q 10 cfs 42
30Q2 cfs 54 •
Average Flow cfs : 162
IWC (%): 33%
Lat. 35' 15'35"N Long. 81°27'26"W
BACKGROUND
The Pilot Creek Wastewater Treatment Plant (WWTP) is a 6.0 MGD treatment facility serving
13,500 residents of Kings Mountain. The facility discharges municipal wastewater (domestic
and industrial) and has a full pretreatment program with seven (7) non-categorical Significant
Industrial Users. The Division will continue to implement the pretreatment program in the
coming permit term.
The Town's treatment system consists of: dual screw pumps, a mechanical bar screens,
Parshall flume with recorder, three aeration basins, three secondary clarifiers, chlorine contact
basins, caustic feed system, dechlorination facilities, aerobic digesters, 2 sludge drying beds,
and a belt press.
PERMIT LIMITATIONS
• BOD summer limits in the permit are based on the water quality model.
• BOD winter limits in the permit are based on the requirements of the 40 CFR 133.102.
• TSS limits in the permit are based on the requirements of the 40 CFR 133.102.
• Ammonia limits in the permit are based on the water quality model. The Division uses
ammonia criteria that were developed by EPA: 1 mg/L - summer; 1.8 mg/L-winter.
• DO limit in the permit is based on the water quality model.
• TRC limit in the permit is based on the North Carolina water quality standards [15A
NCAC 2B .02001.
• pH limit in the permit is based on the North Carolina water quality standards [15A
NCAC 2B .0200].
• Mercury limit is the permit is based on the Permitting Guidelines for Statewide Mercury
TMDL.
• Fecal Coliforms limits in the permit are based on the North Carolina water quality
standards [15A NCAC 213 .0200].
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NPDES NCO020737 Renewal
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• Cyanide limits in the permit are based on the results of the Reasonable Potential
Analysis.
• Thallium limits in the permit are based on the results of the Reasonable Potential
Analysis.
• Arsenic limits in the permit are based on the results of the Reasonable Potential
Analysis.
• Zinc and Copper limits in the permit are based on the results of the Reasonable
Potential Analysis and compliance issues with the Whole Effluent Toxicity Test.
TOXICITY TESTING
Current Requirement: Chronic Ceriodaphnia Quarterly P/F @ 33%
Testing during the months of January, April, July and October.
The City has had problems passing its whole effluent toxicity tests during the last 5 years. A
toxicity reduction evaluation was performed in Jan. 2006 and it was determined that high
levels of zinc was causing the toxicity problems (please see attached).
DWQ requires that the quarterly chronic Ceriodaphnia toxicity tests @ 33% and limits
for Cu and Zn be continued in the renewed permit.
COMPLIANCE SUMMARY
Overall, the facility has experienced numerous compliance issues, please see attached. Most
violations were for limit excursions for pH, Cd, and Zn. The compliance has significantly
improved in 2013 and 2014, there were no limit violations during these years.
INSTREAM MONITORING
Upstream site: Above effluent discharge
Downstream site: NCSR 1103
A review of temperature, DO, pH and conductivity data showed that most of the time water
quality standards were met for temperature and DO. Over the past 3 years there have been
several instances of low pH values both upstream and downstream of the Kings Mountain
discharge.
REASONABLE POTENTIAL ANALYSYS (RPA) RESULTS
Reasonable potential analyses were conducted for CN, As, Cd, chlorides, Cr, Cu, Ni, Zn, and Tl,
please see attached.
The Division also considered data for other parameters of concern in the renewal application.
The majority of the parameters were not detected in the discharge and the rest were below
state water quality standards/EPA criteria.
MERCURY EVALUATION
The mercury evaluation was conducted in accordance with the Permitting Guidelines for
Statewide Mercury TMDL. WQBEL allowable concentration for this facility is 36.5 ng/L. The
maximum detected mercury concentration during the last 5 years was 46 ng/L, which exceed
allowable concentration, but below TBEL of 47 ng/L. Based on the Permitting Guidelines for
Statewide Mercury TMDL, the annual average WQBEL limit of 36.5 ng/L and Mercury
Minimization Plan will be added to the permit. A new mercury limit will become effective in the
51h year of the permit. The monitoring frequency will established as Quarterly.
SUMMARY OF PROPOSED CHANGES
• Based on the Permitting Guidelines for Statewide Mercury TMDL, the annual average
WQBEL limit of 36.5 ng/L will be added to the permit. A new mercury limit will become
effective in the 51h year of the permit. The monitoring frequency will be established as
Quarterly.
• Based on the Permitting Guidelines for Statewide Mercury TMDL, the Mercury
Minimization Plan special condition will be added to the permit (Please see A. (4.)).
• The monthly average limit for As has been reduced to 152.2 pg/L based on the
protection of the aquatic life.
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• The daily maximum limit for As has been reduced to 184.2 pg/L based on the
protection of the human health.
• Monitoring for As has been reduced to monthly based on the statistical analysis of the
effluent data.
• Limits and monitoring for Cd have been eliminated based on the statistical analysis of
the effluent data.
• Monitoring for chlorides has been reduced to quarterly based on the statistical analysis
of the effluent data.
• Monitoring for CN has been reduced to monthly based on the statistical analysis of the
effluent data.
• Monitoring for Cu and Zn has been reduced to monthly based on the statistical analysis
of the effluent data.
• The daily maximum limit for CN has been increased to 59.1 based on the protection of
the aquatic life.
• Daily maximum and monthly average limits for Tl have been added to the permit based
on the statistical analysis of the effluent data.
• Limits for Cu and Zn were reduced based on the statistical analysis of the effluent data.
• Proposed federal regulations require electronic submittal of all discharge monitoring
reports (DMRs) and specify that, if a state does not establish a system to receive such
submittals, then permittees must submit DMRs electronically to the Environmental
Protection Agency (EPA). The Division anticipates that these regulations will be adopted
and is beginning implementation.
The requirement to begin reporting discharge monitoring data electronically using the
NC DWR's Electronic Discharge Monitoring Report (eDMR) internet application has been
added to the permit. [See Special Condition A. (5.)]
PROPOSED SCHEDULE FOR PERMIT ISSUANCE
Draft Permit to Public Notice: July 16, 2014
Permit Scheduled to Issue (tentative): September 8, 2014
NPDES DIVISION CONTACT
If you have questions regarding any of the above information or on the attached permit, please
contact Sergei Chernikov at [phone] or [e-mail].
REGIONAL OFFICE COMMENTS
In the Staff Report, the Regional Office recommends that the permit is renewed
NAME: DATE:
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