WQ0032515_Compliance Evaluation Inspection_20240628

North Carolina Department of Environmental Quality | Division of Water Resources | Raleigh Regional Office
3800 Barrett Drive | 1628 Mail Service Center | Raleigh, North Carolina 27699-1628
919.791.4200

June 28, 2024
Donald Greeley – Director Water Management
City of Durham
101 City Hall Plaza
Durham, NC 27701

Subject: Compliance Evaluation Inspection
Reclaimed Water Generation and Bulk Distribution
Permit Number: WQ0032515
Durham County

Donald Greeley,
On June 25, 2024, Chris Smith of the Raleigh Regional Office conducted a compliance evaluation
inspection of the reclaimed water generation and bulk distribution system located at the Durham Water
Reclamation Facility.

This facility is permitted for operation of a reclaimed water generation and bulk distribution facility
consisting of:
the installation of an on-line turbidimeter and all associated piping, valves, controls, and appurtenances
and the continued operation of reclaimed water generation from NPDES Permit No. NC0023841, two
variable frequency drive (VFD) pumps to maintain pressure to the distribution system, a 4-inch overhead
loading arm, a 3-inch quick connect fitting at ground level for distribution to customers, a sodium
hypochlorite feed system with bulk tank and meter pump to supply chlorine to the pump feed system, a
manual valve at the loading station with a hand held turbidimeter (for use prior to installation of on-line
turbidimeter), flow meter, and residual chlorine monitor, a catch basin that drains to the headworks,
and all associated piping, valves, controls, and appurtenances.

The purpose of this inspection was to ensure compliance with the subject permit. During the inspection,
the cooperation and assistance provided by Brian Merritt and Jason Cash was helpful and appreciated.

This compliance evaluation inspection consisted of the following:
•Review of the permit
•Review of the owner/facility information
•Review of ORC logbooks, calibration documentation, Non-Discharge Monitoring Reports
(NDMR) and
•On-site inspection of treatment components

DocuSign Envelope ID: 2C9AAA51-B577-4D63-9550-92E7CF750A3A
WQ0032515
Durham
June 25, 2024
Page 2 of 3

North Carolina Department of Environmental Quality | Division of Water Resources | Raleigh Regional Office
3800 Barrett Drive | 1628 Mail Service Center | Raleigh, North Carolina 27699-1628
919.791.4200

The current permit was effective December 1, 2021 and expires on January 31, 2028.

The inspector reviewed the facilities Operation and Maintenance Plan, which was found to be adequate.
The flowmeter used by the facility is a factory calibrated Seimens magmeter and cannot be field
calibrated. The handheld turbidimeter calibration records were not available during the inspection.
Brian Merritt stated during the inspection that he will provide calibration documentation as soon as
possible. The facility is certified to monitor and collect two field parameters’ values (chlorine and
turbidity) in house. A calibration log is maintained for the chlorimeter, but residual chlorine values are
not a parameter that is required to be reported by the permit. Chlorine content is monitored by a
SCADA connected monitor and maintained around 1ppm. Sodium Hypochlorite is added to the
reclaimed water pump by quill at delivery as the UV disinfection system for the NPDES discharge is after
the reclaimed water pumps.

Residuals are managed under NPDES permit NC0023841.

Reclaimed water is distributed to the reclaimed system by two (2) pumps and is used on site for
equipment washing, seal water, odor control, firefighting (if necessary). The facility has not distributed
any reclaimed water from the bulk distribution station in over a year. A Seimens magmeter is installed
near the bulk loading station to track distribution. Turbidity and chlorine are recorded as water is
pumped to customer tanks.

Operation and Maintenance documents are maintained on the facility computer system and a printed
copy was available during the inspection. All reclaimed water users and customers receive training from
facility staff prior to receiving reclaimed water. Reclaimed water system components are properly color
coded.

Overall, the facility appears to be well-maintained and operated and in compliance with permit
conditions.

Note: The facility permit requires continuous turbidity monitoring once reclaimed water begins to be
sent to the Mist Lake facility listed as PPI-003 in Attachment A in the permit. Until that time, the facility
should continue to monitor turbidity when it is bulk distributed to customers using the above-
mentioned hand-held turbidimeter. Additionally, until such time that any reclaimed water is distributed
from the bulk filling station or to the Mist Lake facility, and as long as all generated reclaimed water
continues to be used solely within the facility and returned to the treatment system, the facility may
submit monthly Non-Discharge Monitoring Reports (NDMRs) indicating “No Flow” on the forms.

DocuSign Envelope ID: 2C9AAA51-B577-4D63-9550-92E7CF750A3A
WQ0032515
Durham
June 25, 2024
Page 3 of 3

North Carolina Department of Environmental Quality | Division of Water Resources | Raleigh Regional Office
3800 Barrett Drive | 1628 Mail Service Center | Raleigh, North Carolina 27699-1628
919.791.4200

If you have any questions about this inspection or this letter, please contact Chris Smith at
[e-mail] or 919-791-4257.

Sincerely,

Michael Hall, Regional Supervisor
Water Quality Regional Operations Section
Raleigh Regional Office
Division of Water Resources, NCDEQ
Attachments: EPA Compliance Inspection Report
cc: Laserfiche

DocuSign Envelope ID: 2C9AAA51-B577-4D63-9550-92E7CF750A3A