NC0039578_NOV2022LV0072 Response_20220201

TUCKASEIGEE WATER & SEWER AUTHORITY
SEAVINQ JACKSON COUNTY
1246 West Main Street
Sylva, NC 28779 \ J
Phom:(828) 586,5189 a Fax:(828) 631,9089
Feb 1, 2022
Water Oudity Regional Opor.'tione.
NCDEQ/ARO Asheville l onglond Office
Div. of Water Resources
2090 US 70 Hwy
Swannanoa, NC 28778
Subject: Oct 4-9" weekly coliform violations
TWSA Plant #1
Permit # N00039579
Attn: Stephanie Williams
Water Quality Regional Operations Section
Asheville Regional Office
Division of Water Resources, NCDEQ
Dear Ms Williams
As noted, the Tuckaseigee Water and Sewer Authority had a violation of the permitted weekly
limit for Fecal Coliform the week of Oct 4f6 - 9"
The violation resulted from two different factors. A breakdown of the dryer used to process
sludge occurred Jane 161h, 2021. The parts to repair the dryer were to arrive within 10 days but
were not received until the 23r° 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 SBRs resulting in solids carryover into the effluent.
This condition makes it much more difficult to disinfect.
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 until the first week of Oct when evidence that
the strength of the chlorine shipment received on 9/2/21 was beginning to wane. Operators
began to raise chlorine feed rates in an effort to maintain compliance. The following summary
shows feed rates and chlorine residuals obtained during the week.
This institution is an equal opportunity provider and employer.

Free C12
Chlorine (12-15%)
Permit Violation-
Fecal Colifonn
Residual Check
Feed Rate
(cfu/100m1s)
mg/l
gal/hr
10/4
10300
0.26
5.0>10.4>15.0
1015
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
An expected chlorine shipment scheduled for the week of OCT 4" was 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 coli€ome 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
bra. 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 week of Oct 10-15" both SBRs were operating normally, water quality and clarity
had returned and all parameters were 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: ill
* There was no reasonable explanation determined for having a 4200 cfu count on a sample
that had a frce C12 check before de -chlorination of 1.21 mg/l.

Summary- 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 hard 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
Tuckaseigm Water and Sewer Authority
[e-mail]
828-508-1072
xc: Mr Daniel Manning, Executive Director, TWSA