NC0047384_Report_20210514

City of Greensboro
L J North Carolina
Water Resources Department
April 29, 2021 Certified Mail 7003 1680 0001 0765 8930 Return Receipt Requested
North Carolina Department of Environmental Quality, Division of Water Resources
Attn: Jordan Lake Watershed Coordinator, Mr. Mike Templeton (via email and USPS)
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
RECEIVEDiNCDEQIDWR
MAY 0 5 2021
Water Quality
Permitting Section
RE: T. Z. Osborne (TZO) NPDES Total Nitrogen Reduction Schedule Report for CY2020
Submitted in Response to NPDES Permit NC0047384 Part 1-A.(4)
To Whom It May Concern:
This correspondence will serve as the City of Greensboro Total Nitrogen Reduction Schedule Report for
CY2020 in order to comply with Part 1-A.(4) of the TZO NPDES permit NC0047384. The permit includes
the following requirements for the 2020 report:
• Complete construction of Packages 2, 3 and 4 (complete BNR facility) and conduct BNR
Optimization of the T. Z. Osborne BNR Project.
• By April30, 2021, submit report to DWR on completion and optimization of Packages, 2, 3 and 4
of the T. Z. Osborne BNR Project. [In response to a request by the City of Greensboro, on
9/17/2020 NCDEQ granted a 120-day extension until April 30, 2021, to complete construction of
Package 4 of the T. Z. Osborne WWTP project and submit a report on completion and
optimization of Packages 2, 3 and 4.]
■ Note: In September 2014, the City of Greensboro decided to continue the Haw River Arm Study
for at least an additional 12 months (through September 2015). As indicated in previous TN
Reduction Schedule Reports the City then decided to continue the study until further notice.
Jordan Lake Haw River Arm Study Update
• The Haw River Arm Study began in October 2013 and includes 2 sampling events per month.
■ Samples are collected from two NCDEQ Sampling Sites: Site 055C— Below Pittsboro at the upper
end of the Haw River Arm and Site 055E— Near the Jordan Lake Dam on the Haw River arm
• All lake sampling and laboratory analyses are conducted by Meritech, a State -certified
commercial laboratory at a cost of $1885/month.
■ The following parameters are included in the study:
Field Parameters
Dissolved Oxygen (in mg/I)
pH (in standard units)
Specific Conductance (in umho/cm)
Temperature (in °Celsius)
Other Parameters
Total Suspended Solids — Standard Methods 2540 D (in mg/I)
Turbidity — EPA Method 180.1 (in NTU)
Ammonia -Nitrogen — EPA Method 350.1 (in mg/I)
Total Kjeldahl Nitrogen — EPA Method 351.1 (in mg/I)
Nitrate/Nitrite Nitrogen — EPA Method 353.2 (in mg/I)
Total Phosphorus — EPA Method 200.7 (in mg/I)
Chlorophyll a — EPA Method 445.0 (in pg/l)

April 29, 2021 - T. Z. Osborne NPDES Total Nitrogen Reduction Schedule Report for CY 2020 Page 2
Jordan Lake Haw River Arm Study Interim Data Summary Report (October 2013-December 2020)
• 326 samples have been collected since October 2013
• Results from Site 055C: Below Pittsboro at the upper end of the Haw River Arm
o 12 WQS exceedances for pH (12/161 = 7.5% exceedances)
o 24 WQS exceedances for turbidity (24/163 = 14.7% exceedances)
o 18 WQS exceedances for chlorophyll a (18/163 = 11.0% exceedances)
• Results from Site 055E: Near the Jordan Lake Dam on Haw River Arm
o 4 WQS exceedances for pH (4/163 = 2.5% exceedances)
o 11 WQS exceedances for turbidity (11/163 = 6.7% exceedances)
o 8 WQS exceedances for chlorophyll a (8/163 = 4.9% exceedances)
TZO BNR Project Packages Activities Update
• Construction on Package 1 was completed on October 22, 2018.
• Construction on Package 2 was completed on April 10, 2018.
• Construction on Package 3 was completed on March 29, 2018.
• Package 4 of the T. Z. Osborne Biological Nutrient Removal (BNR) Project was bid on September 28,
2017, the Notice to Proceed was issued on January 16, 2018 and construction began in February
2018. The 4th phase of the $120 million project included complete retrofitting of the existing twelve
aeration tanks for 5-Stage BNR operation and construction of six new 5-stage BNR aeration tanks.
• From January 2020 through August 2020 the Total Nitrogen (TN) End -of -Pipe (EOP) loading from the
TZO POTW averaged 121,238 pounds/month.
• In May 2020, the first retrofitted aeration tank (Basin 3), was put into 5-stage BNR operation mode
for equipment and process testing and overall optimization purposes. Basins 1, 2 and 4 were
transitioned to 5-stage BNR in June 2020. Aeration tanks 5-12 were transitioned to 5-stage BNR
operation in November 2020. Since then, the original 12 tanks have been in BNR optimization mode
to meet the Total Nitrogen effluent limits effective 1-1-2021. Three (3) new 5-stage BNR tanks
(Basins 13, 14, and 15) were completed in April 2021 and provide process redundancy.
• From September 2020 through January 2021 the TN EOP loading from the TZO POTW averaged
60,639 pounds/month.
• The TZO NPDES TN EOP Annual Mass Limit of 891,272 pounds per year was effective January, 1,
2021 (for CY 2021). The new limit corresponds to an average loading of 74,372 pounds/month.
• Although the TN Annual Mass Limit was not in effect until January 1, 2021, the TZO POTW met the
average monthly EOP TN loading (based on the EOP annual Mass Loading) for the 5-month period
beginning in September 2020 through January 2021 and in March 2021.
NPDES Permit EOP Annual Mass Limit = 891,272 lbs/yr [74,372 Ibs/mo]
Month
TN EOP Loading (in Ibs/month)
September 2020
74,220
October 2020
64,166
November 2020
68,455
December 2020
60,022
January 2021 [TN Annual Mass Limit Effective 1-1-211
36,333
February 2021
106,812
March 2021
51,331
PO Box 3136 Greensboro, NC 27402-3136 www.greensboro-nc.gov 336-373-CITY (2489) TTY # 333-6930

April 29, 2021 - T. Z. Osborne NPDES Total Nitrogen Reduction Schedule Report for CY2020 Page 3
■ A combined sequence of events in February 2021 (high flows due to rainfall, WWTP process
shutdowns needed by contractor, a structural failure of the fluidized bed incinerator, and increased
mixed liquor solids inventory) impacted the nitrification/denitrification BNR process and resulted in
a significant increase in the TZO total nitrogen effluent load for the month.
• In March 2021 the 5-stage BNR process returned to optimal operation.
• The Package 4 BNR process construction was substantially complete on April 29, 2021 with the
exception of new aeration basins 16, 17 and 18. Effluent total nitrogen data/loading calculations
confirm the ability of the TZO POTW to meet the annual mass loading values from the Jordan Lake
Rules.
• The contractor (Adams Robinson) and project engineers (Hazen & Sawyer) anticipate that the
Engineer's Certification of the entire Package 4 Authorization to Construct will be issued in 3'd
quarter 2021. At that time, the TZO POTW will have a design capacity of 56 MGD, which will trigger
the NPDES Permit NC0047384 "Beginning upon expansion to 56 MGD" Tier [Part I. A.(2.) page 5 of
18]. It will also trigger the 6-month period of daily analyses required for carbonaceous biochemical
oxygen demand (CBOD), total suspended solids (TSS) and fecal coliform (from Footnote 13 on page
6) in order to reconfirm the exceptional performing facility status. It is expected that the effective
date of the 56 MGD Tier would begin on the first day of a calendar month.
Sincerely,
(\kuJutw C.o
Martie Groome, Laboratory and Industrial Waste Section Supervisor
Phone: [phone] Email: [e-mail]
cc: Mike Borchers, Water Resources Director (via email)
Kristine Williams, Water Resources Assistant Director (via email)
Elijah Williams, Water Reclamation Manager (via email)
Bradley Flynt, T. Z. Osborne ORC (via email)
Alicia Goots, Laboratory Coordinator (via email)
Michael Montebello, NCDEQ, NPDES Permitting Supervisor (via email)
Lon Snider, NCDEQ, Winston-Salem Regional Office Supervisor (via email)
Jenny Graznak, NCDEQ Winston-Salem Assistant Regional Office Supervisor (via email)
PO Box 3136 Greensboro, NC 27402-3136 www.a'reensboro-nc.gov 336-373-CITY (2489) TTY # 333-6930