NC0021156_COMPLIANCE_20191122

STORMWATER DIVISION CODING SHEET
NCS PERMITS
PERMIT NO.
DOC TYPE
❑ FINAL PERMIT
❑ MONITORING REPORTS
❑ APPLICATION
e�COMPLIANCE
❑ OTHER
DOC DATE
r
❑ C 1�
YYYYMMDD

Performance Report f 2018/2019
MOUNT
HoLLY
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2018 - 2019
Annual Sewer and Collections System
Performance Report
The North Carolina Clean Water Act of 1999 requires the City of Mount Holly to provide an annual
report to its customers. Also to the North Carolina Department of Environment and Natural Resources
(NCDENR), to summarize the sewage treatment works and collection system's performance over the last
year.
You may Review Act at:
https://www.ncleg.net/Sessions/1999/Bills/House/PDF/Hll6Ov4.pdf RECEiVED
Mount Holly Permits
NPDES Permit: NC0021156 NOV 2 2 26i9
Land Application Permit: WQ0001863
Collections System Permit: NCCS00059
Storm Water for WWTP: NCG110000 (General)
Overview
Wastewater from the City of Mount Holly Residents, Businesses, and Industries flow by gravity
through Approximately 100 miles of sewer lines, through approximately 2568 manholes, to one of 13 lift
stations. The Wastewater then flows to the City of Mount Holly's Wastewater Treatment Facility where
it is then treated. When the wastewater enters the facility it is screened to remove any large debris.
After screening the wastewater flows by gravity through 2 (two million gallon) aeration basins which is
where the biological portion of the treatment occurs. In the biological process tiny microscopic bacteria
and organisms treat the wastewater and oxygen is added. After aeration the wastewater flows to two
clarifiers where the wastewater is slowed down and the biological organisms are separated from the
water by gravity. After clarification the biological organisms are sent back to the beginning of the
process and met with incoming flow, Once the Organisms have been through the process enough they
get pumped into two 750,000 gallon digesters where it is aerobically digested prior to Land Application
on farm land for the re -use of the nutrients. The treated water leaves the clarifiers and flows into two
chlorine contact basins where the water is met with chlorine for disinfection purposes. Once any
remaining bacteria has been killed by the chlorine the treated water flows through sulfur dioxide to
remove the residual chlorine prior to discharge into the Catawba River. Below is a diagram of the
treatment process at the City of Mount Holly Wastewater Treatment Facility.
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Diagram Of Wastewater Treatment Flow
Land Application jor re -use _ _.

Performance Report 12018/2019
Sampling
Each year the City of Mount Holly performs over 37,000 measurements and chemical analysis
annually to comply with permit requirements, treat the wastewater and safely return it to the
environment. The City's staff of trained and certified operators are committed to the goal of providing
the wastewater customers with the most efficient, cost effective wastewater treatment. Below is a table
of the current discharge limitations and the average daily discharge from the Mount Holly Wastewater
Treatment Facility.
Monthly
Weekly
Daily
Daily
Annual
Average
Maximum
Minimum
Average
Average
Maximum
Minimum
Limit
Discharge
Daily
Daily
limit
limit
limit
limit
7/1/17-
Discharge
Discharge
6/30/18
Flow in
4.0 (MGD)
2.223
Million
MGD
Gallons per
Day (MGD)
Biochemical
30.0 mg/I
45.0 mg/I
3.75mg/I
Oxygen
Demand
(BOD)
Total
30.0 mg/I
45.0 mg/I
9.46 mg/I
Suspended
Solids (TSS)
Fecal
200/100ml
400/100ml
8.89/100ml
(Geometric
Mean)
Total
50 ug/I
27.54 ug/I
Residual
Chlorine
(TRC)
Dissolved
5.0 mg/I
5.39 mg/I
Oxygen
(DO)
PH
9.0 su
6.0 su
7.5 su
6.1 su
Annual
18,250
17135 lbs
2018 Total
Ibs
Phosphorus
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Performance Report 1 Z018/2019
Performance
The City of Mount Holly is committed to constantly improve our Wastewater Treatment Facility and
Collections System to protect the customers and the environment from the potential harm of
inadequately treated wastewater.
Wastewater Treatment Plant
The City of Mount Holly Wastewater Treatment Plant had 3 permit violations for the 2018/2019
fiscal year. The I" violation was for exceeding the TRC limit of 50 ug/I of the Total Residual
Chlorine in the final effluent. The violation occurred on July 3rd 2018, and the result was 50 ug/I.
The 2nd violation was for not maintaining a minimum dissolved oxygen level of 5.0 mg/I in the
final effluent. The event occurred on September 17th 2018, and the dissolved oxygen result was
recorded as 3.72 mg/I. The 3rd violation was for not maintaining a minimum dissolved oxygen
level of 5.0 mg/I in the final effluent. The event occurred on June 101h 2019, and the dissolved
oxygen result was recorded as 0.3 mg/l. At the time of this report there is NO Notice of violation
issued for this event. In both dissolved oxygen occurrences, the low result was due to the
excessive amount of rain the fell in the prior days. At this time there are NO known adverse
environmental impacts and we strive to help improve the environment as much as possible.
Wastewater Collections System
The City of Mount Holly Wastewater Collection System had 3 permit violations for the
2018/2019 fiscal year. The I" violation occurred on 4-2-18 and lasted for 1 hour and resulted in
250-500 gallons reaching a body of water. The 2"d violation occurred on 5-1-18 and lasted for 1
hour and resulted in 100 gallons reaching a body of water. The V violation occurred on 10-12-
18 and lasted for 1 hour. At the time of this report there have been NO notice of violations
issued. At the time of this report there have been NO known adverse environmental impacts.
Public Notification How You Can Help Protect the Environment
In the event of an overflow the City has the responsibility to repair the problem causing the overflow
and mitigate any damage. The City also has to report the spill to the State. If the spill exceeds 15,000
gallons, a public notice is issued at the time of the spill. The State can fine the City for large overflows.
Most overflows are caused by grease or obstructions in the system. You can help stop overflows by
keeping fats, oils and grease out of your drain. You can also call City Hall or the 24hr Utility Customer
Service at [phone] if you see a manhole overflowing, missing manhole cover or broken pipes.
If you have any questions concerning our Wastewater system or this report please contact the
Wastewater Treatment Facility at [phone].
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Performance Report 12018/2019
Name of Regulated Entity and Responsible Contact
Mount Holly Wastewater Treatment Plant
City Manager: Danny Jackson
P.O. Box 406
Mount Holly, NC 28120
704-827-3931
(Wastewater Treatment)
Operator in Responsible Charge: Doug Shoutd
P.O. Box 406
Mount Holly, NC 28120
704-827-4261
(Collections System)
Operator in Responsible Charge: Robert Stewart
P.O. Box 406
Mount Holly, NC 28120
704-201-9565
Certification
I certify, to the best of my knowledge, this report is accurate and complete meeting the requirements of
the North Carolina House bill 1160, 1999 Clean Water Act, and the guidance provided by (DWQ) Division
of Water Quality Compliance and Enforcement Unit's letter of October 10, 1999.
Date
This report is posted on www.mtholly.us and at City Hall
Submit 3 copies to:
System Performance Annual Report
North Carolina Division of Environmental Quality
1617 Mail Service Center
Raleigh, NC 27699-1617
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