NC0069841_NOV-2020-PC-0400_20200922

Department of Public Works
Water/Wastewater Division
4600 Goldmine Road
Monroe, NC 28110
T. 704-289-1434
F. 704-289-7395
www.unioncountync.gov
September 15, 2020
W. Corey Basinger,
Regional Supervisor
NCDEQ
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Dear Mr. J3, singer,
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rW t�iC.0 e('-10NA1 0Ff:jCC
This letter is in response to NOV-2020-PC-0400, regarding the requirement for an Ammonia
Corrective Action Plan for the Crooked Creek Water Reclamation Facility.
On September 1 st 2020 Mr. Scheller conducted an annual compliance inspection of our Crooked
Creek WRF and discovered this plan was not completed as required by the permit (p.11, A.
(5.),1&2). The Ammonia Corrective Action Plan was to be submitted by January 31, 2019 and a
summary of actions taken by January 31, 2020. We have since developed the plan which has
been submitted to both your office and the NPDES permitting office in Raleigh on September 3rd
2020. A copy is attached to this letter. Our ammonia results have varied between 0.96 and
<0.1 mg/I for the period August 1st, 2018 and July 71h, 2020—well within permit limits.
If you have any further questions, please let me know at 704-296-4215.
Sincerely,
LL14
Andrew Neff, PE
Water & Wastewater Division Director
Attch. Ammonia Corrective Action Plan
Cc: Hyong Yi, Public Works Administrator
Josh Brooks, Asst. Div. Director, Water & Wastewater
Bart Farmer, WRF Superintendent

Union County Public Works
Water/Wastewater Division
4600 Goldmine Road
Monroe, NC 28110
T. 704 289-1434
F. 704 289-7395
www.unioncountync.gov
To:
NCDEQ
From:
Union County Public Works,
WaterlWastewater Division
Subject:
Crooked Creek WRF NCO069841
Corrective Action Plan
Date:
09/03/20
This Corrective Action Plan is being submitted per requirement as stated in NPDES permit #NC0069841,
page 11, A.(5.), satisfying paragraphs 1 & 2.
The Crooked Creek WRF has historically produced excellent results in the area of compliance with the
Ammonia -Nitrogen limits. We achieve this by keeping a MLSS concentration in the neighborhood of 3200
mg/l, as well as maintaining a dissolved oxygen concentration between 1.0-3.0. This methodology is proven
out by the results of our sampling which show that we are already meeting, or exceeding, the more stringent
final limits required in 2022 (page 5, Table A.(2.) of the listed permit).
The attached spreadsheet shows the sample results for the past 24 months. The results are summarized
here:
O 307 Samples
® 253 Results of <0.1 mg/l (95% non -detect rate)
• High result of 0.96mg/l
An interesting note: We experienced a catastrophic failure of the shaft on aerator #204, and had to get the
part custom machined. That aerator was down from 7/1/20 until 7/29120. The entire period had results of
<0.1 mg/i.
Union County Q,Overr-rrrietit: iilitILIkes
page 'I

Union County Public Works
Water/Wastewater Division
4600 Goldmine Road
Monroe, NC 28110
T. 704-289-1434
F. 704-289-7395
www.unioncountyne.gov
NOV/NOD:
During this 24 month time period, we only had one violation. This violation (NOV-2018-MV-0171)
was a monitoring frequency violation. During the week this occurred, the WRF experienced a
hurricane and staff were unable to sample the required three times that week.
Future actions:
We are in the pre -bid phase of upgrades to the aeration process. We will be retiring the paddle brush
aerators and installing disc aerators, The disc aerators will provide greater mixing, improved
aeration, better nitrification, and increased energy efficiency.
The Union County Master Plan projects the building of a larger regional WRF lower on the Crooked
Creek basin in the next few years. This facility will replace both the current Crooked Creek WRF and
the Grassy Branch WRF.
The next update to this plan will be submitted prior to January 31, 2021 to satisfy requirement in
paragraph 3 on page 11 of the listed permit.
Sincerely,
Bart T. Farffjer
�r
WRF Superintendent
Union County Public Works, Water/Wastewater Division
Union Coa.asaky Grioverrrirlenc Meeting t�rlinr.acc.s
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