NC0039578_NOV2021LV0781 & NOV2021LV0795 Response_20211029

TUCKASEIGEE WATER & SEWER AUTHORITY
SERVING 1ACKSON COUNTY ggq7�
1246 West Main Street
Sylva, NC 28779
Phone: [phone] • Fax: [phone] OCT 2 9 2�2�
Oct 26th, 2021
NCDEQ/ARO
Div. of Water Resources
2090 US 70 Hwy
Swannanoa, NC 28778
Subject: Timeline of non-compliance events @
TWSA Plant #1
Permit # NCO039578
Attn: Stephanie Williams
Water Quality Regional Operations Section
Asheville Regional Office
Division of Water Resources, NCDEQ
Dear Ms Williams
Water Quality Regional Operations
Asheville Regional Office
The Tuckaseigee Water and Sewer Authority has had several violations of the NPDES permit
in recent months. The violations have all been weekly violations of the Fecal Coliform limits
of the permit with the exception of a weekly violation of the BOD permitted value in Aug.
As noted in NOV-2021-LV-0781 the violations first occurred the week ending Aug. 28. 2021.
The following is a summary of the violations
that have occurred:
Free C12
Chlorine (12-15%)
Permit Violation-
Fecal Coliform
Residual Check
Feed Rate
(cfu/100m1s)
mg/1
gal/hr
8/23
995
0.32
2.6
8/24
6400
0.13
6.3-9.6
8/25
50
0.61
15.0
8/26
345
0.29
15.0-10.2
8/27
286
0.33
10.2
Weekly Geometric Mean 500.5
This institution is an equal opportunity provider and employer.

Permit Violation- Fecal Coliform
(cfu/100m1s)
8/30
15800
8/31
2300
9/1
6000
9/2
7333
913
610
Weekly Geometric Mean 2050
Free C12 Chlorine (12-15%)
Residual Check Feed Rate
mg/I gal/hr
0.01
20.0
0.31
20.0
0.02
20.0
0.49
3.0
1.25
3.0
0,47
3.0
Note that the C12 residual check is documented each day at the end of the C12 contact chamber
at the time of obtaining the effluent fecal coliform grab sample. This helps with chemical
dosage and process control decisions.
The chlorine feed rate is documented to show that operators were responding to deteriorating
disinfection with higher feed rates. On 9/2 a new shipment of liquid chlorine was delivered
which resulted in better disinfection and lower feed rates.
Permit Violation-
BOD
(mg/1)
8/30
174
8/31
11.9
9/1
13.7
9/2
14.7
9/3
14.5
Weekly Avg.
45.8
There is not a valid reason for the high bod value on the 30th and it is considered to be an
anomaly, possibly caused by elevated ammonia nitrogen levels resulting in an unusually high
oxygen demand. It is noted that TSS in this sample were only 4.7 mg/l.
These violations resulted from two different factors. A breakdown of the dryer used to process
sludge occurred June 16`h, 2021. The parts to repair the dryer were to arrive within 10 days but
were not received until the 23`d of August. These 68 days of an inability to move sludge from
the process at the facility resulted in high levels of sludge retained in the system. These high
levels caused inefficient settling in the SBR s resulting in solids carryover into the effluent.
This condition makes it much more difficult to disinfect.

It should be noted that the TWSA Plant #1 treats sludge from the other three Authority owned
facilities as well as the septage that is generated by residences in Jackson Co. and that is
hauled to the TWSA #1 facility by private septage haulers.
The residuals generated by these other sources were accommodated at the TWSA Plant #I
during the dryer down time, resulting in no non-compliance conditions at the other facilities
owned by the Authority and no work stoppage of private haulers.
The second factor leading to non-compliance was a steady weakening of the strength of the
liquid chlorine stored onsite and a delay in getting a new shipment of chemical. These delays
were attributed by the chemical supplier to a lack of product and a lack of drivers to deliver
product.
The facility was relatively stable and compliant after the first week of Sept. 2021 until the first
week of Oct when evidence that the strength of the chlorine shipment received on 9/2 was
beginning to wane. Operators once again began to raise feed rates in an effort to maintain
compliance.
Free C12 Chlorine (12-15%)
Permit Violation- Fecal Coliform Residual Check Feed Rate
(cfu/100mis) mg/1 gal/hr
10/4
10300
0.26
5.0>10.4>15.0
10/5
613
0.69
15.0>25.0>30.0
10/6
6000
0.25
30.0
10/7
10600
0.27
30.0
10/8*
116
1.48
3.0
10/9
_ 270
1,17
3.0
Weekly Geometric Mean 1525
A chlorine shipment was once again delayed due to the chlorine production facility being shut
down for scheduled maintenance. The TWSA was forced to obtain 375 gal totes of liquid
chlorine from another supplier. The chlorine from these totes was fed to the influent to the
chlorine contact chambers starting on 10/8. This resulted in a downward trend to coliform
numbers but a high residual had to be maintained to obtain relatively low numbers.
During this same time period 10/4-10/9, SBR #1 had to be taken off line on two separate
occasions to allow it to regain an appropriate population of bacteria. Mixed liquor in the SBR
was dark and black without a good healthy brown color. After 24 hours of aeration the basin
was again brought online only to have to again be sidelined and aerated for an additional 24
hrs. No cause was able to be determined as to why the bacteria population died. With the one
SBR sidelined the second SBR had to operate in a filled settle and decant mode which did not

have the water clarity that two SBR's would have had. This decreased clarity did not
appreciably effect BOD or TSS numbers but did make it more difficult to obtain adequate
disinfection..
As of the 22"d of Oct., both SBRs are operating normally, water quality and clarity are good
and all parameters are well within permitted values.
Free C12 Chlorine (12-15%)
Fecal Coliform Residual Check Feed Rate
(cfu/100mis) mg/1 gal/hr
10/11
4200*
1.21
3.2
10/12
29
1.65
3.2>5.1
10/13
39
0.62
5.1
10/14
52
> 2.0
5.1>7.5
10/15 _ _
67
1.37
7.5>5.0
Weekly Geometric Mean: III
* There was no reasonable explanation determined for having a 4200 cfu count on a sample
that had a free C12 check before de -chlorination of 1.21 mg/l.
Fecal Coliform
(cfu/100mis)
Free C12
Residual Check
mg/I
Chlorine (12-15%)
Feed Rate
gal/hr
10/18
65
1.25
5.0
10/19
13
1.22
5.0
10/20
12
1.03
5.0
10/21
4
1.19
5.0
10/22
22
1.18
5.0>4.0
Weekly Geometric Mean:
15
Summary- Non-compliance at the facility has been largely related to Fecal Coliform. The
sludge dryer being down for repair for an extended period of time contributed greatly to the
problem. Supply chain logistics and shelf life problems with liquid chlorine caused conditions
that led to non-compliance.
A soured/malfunctioning SBR happened at a time when normal disinfection was already in
jeopardy and resulted in a lower level of disinfection than normal.
The TWSA staff worked longer and additional hours in an effort to maintain compliance but
we were unfortunately unsuccessful. The facility did not become non -compliant "overnight"

and even after repairs were made to the dryer it took some time to achieve the correct
population and makeup of bacteria to return both SBRs to compliant levels.
I hope the above documentation of events leading to violations of the permit is understandable
and sufficient. I regret the violations of the permit and be assured that my staff and myself
have done all we can to achieve and maintain compliance.
Please contact me with any questions or comments.
Sincerely,
Stan Bryson
Wastewater Plant Operations Superintendent
Tuckaseigee Water and Sewer Authority
xc: Mr Daniel Manring, F.,xecutive Director, TWSA