NC0020800_Fact Sheet_20190725

Fact Sheet
NPDES Permit No. NCO02O8O0
Permit Writer/Email Contact Nick Coco, [e-mail]:
Date: July 7, 2018
Division/Branch: NC Division of Water Resources/NPDES Complex Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
® Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 21) requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant/Facility Name:
Town of Andrews/Andrews Wastewater Treatment Plant (WWTP)
Applicant Address:
PO BOX 1210, Andrews, NC 28901
Facility Address:
464 Reagan Avenue, Andrews, North Carolina 28901
Permitted Flow:
1.5 MGD
Facility Type/Waste:
MAJOR Municipal; 94% domestic and 6% industrial
Facility Class:
Grade III Biological WPCS
Treatment Units:
Influent communicator, bar screen, grit chamber, dual trickling filter,
dual secondary clarifier, aerated sludge digester, chlorine contact
chamber, sulfur dioxide dechlorination, emergency stand-by power
Pretreatment Program (Y/N)
Y
County:'
Cherokee
Region
Asheville
Briefly describe the proposed permitting action and facility background: The town of Andrews has
applied for an NPDES permit renewal for the Andrews WWTP at 1.5 MGD. This facility serves a
population of 1,500 residents. Industrial wastewater is accepted from 1 categorical SILT under an approved
pre-treatment program. Treated wastewater is discharged into an effluent channel which flows into the
Valley River, a class C-trout water in the Hiwassee River Basin. The facility has a primary Outfall 001. In
their renewal application, the Permittee noted that approximately 100,000 gallons of flow per day are
gained due to inflow and infiltration. The Andrews Sewer Collection Department is conducting ongoing
identification and repair of problem areas.
Basin Planning — According to the 2012 Hiwassee River Basin Plan, the Town of Andrews is located in
the Upper Valley River and the Andrews WWTP "needs to improve its operation and maintenance regime
to avoid future violations." The Basin Plan does not mention impairments in this segment of the Valley
River.
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The Town of Andrews received Authorization to Construct permit 02080OA01 in September 2016 for the
installation of a new 3.75 MGD mechanical bar screen and replacement of their existing manual bar
screen, the rehabilitation of the existing North trickling filter by replacing media and rehabilitation of
distributor rotating mechanism, the rehabilitation of the South trickling filter rotating mechanism, the
repair of the South secondary clarifier, the installation of a chlorination/dechlorination integrated
automatic feed controller system, the installation of a new chlorine residual analyzer and the replacement
of the aerobic digester aeration system. The Town reached a settlement agreement with the State in 2017,
which reduced the money owed to the State due to the Town's numerous violations but required the
complete construction and return to consistent compliance with their NPDES permit. In February 2018
the Town of Andrews submitted a quarterly report documenting that the installation of the new
mechanical bar screen and replacement of the existing manual bar screen and the replacement of the
aerobic digester aeration system were completed. The Town also reported that the installation of the
chlorination/dechlorination integrated automatic feed controller system and the new chlorine residual
analyzer was 90% complete. By March 2018, all work was completed. The Engineer's certification was
received on April 24, 2019.
2. Receiving Waterbody Information:
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfall 001 — Valley River
Stream Segment:
1-52
Stream Classification:
C-Trout
Drainage Area (mi2):
52.4
Summer 7Q10 (cfs)
15
Winter 7Q10 (cfs):
19
30Q2 (cfs):
30
Average Flow (cfs):
130
IWC (% effluent):
13%
303(d) listed/parameter:
Not Listed
Subject to TMDL/parameter:
Yes- State wide Mercury TMDL implementation.
Subbasin/HUC:
Hiwassee Sub Basin 04-05-02/HUC# 06020002
USGS Topo Quad:
G3NE
3. Effluent Data Summary
Effluent data for Outfall 00 is summarized below for the period of December 2014 through December
2018.
Table 1. Effluent Data Summary Outfall 001
Permit
Parameter
Units
Average
Max
Min
Limit
Flow
MGD
0.65
3.165
0.094
MA 1.5
WA 30.0
BOD, 5-day (20C)
mg/1
24.7
82.2
4.1
MA 45.0
WA 18.0
NH3N summer
mg/1
6.5
31.4
0.5
MA 6.0
NH3N winter
mg/1
4.7
18.6
0.3
WA 35.0
MA 14.7
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WA 45.0
TSS
mg/l
25.5
127.1
3.6
MA 30.0
6.0 < pH <
pH
SU
6.4
8.1
5.4
9.0
(geometric)
Fecal coliform
#/100 ml
36.6
20700
2
WA 400
MA 200
DM 28.0
TRC
µg/1
15.4
> 500
< 10
(< 50
compliance)
Temperature
° C
17.1
26.2
6.3
TN
mg/l
10.6
15.6
5.71
TP
mg/l
2.3
5.2
0.95
Total Copper
ug/1
13.5
249
0.7
Total Zinc
ug/1
40.9
75
19
MA-Monthlv Average. WA-Weeklv Average. DM -Daily Maximum. DA=Daily Average
4. Instream Data Summary
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/l of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other
instream concerns. Instream monitoring may be conducted by the Permittee, and there are also
Monitoring Coalitions established in several basins that conduct instream sampling for the Permittee (in
which case instream monitoring is waived in the permit as long as coalition membership is maintained).
If applicable, summarize any instream data and what instream monitoring will be proposed for this
permit action: Instream Monitoring is not required for this facility. In discussing the prospect of
including instream monitoring requirements with the basin planner for the Hiwassee River Basin, it was
determined that the addition of instream monitoring at this facility is not necessary and DWR ambient
sampling is being performed in this stream. The last Integrated Report conducted in 2016 indicates no
impairments in the stream segment. No changes are proposed.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): N
Name of Monitoring Coalition: NA
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): In 2015, the facility reported
2 BOD limit violations, 8 total residual chlorine limit violations, 5 fecal coliform limit violations, 2
ammonia limit violations, 6 pH limit violations and 4 total suspended solids limit violations. The facility
reported 7 BOD limit violations, 4 fecal coliform limit violations and 6 ammonia limit violations in 2016.
The facility reported 6 BOD limit violations, 1 fecal coliform limit violation, 6 ammonia limit violations
and 10 total suspended solids limit violations in 2017. Lastly, the facility reported 1 total suspended solids
limit violation in 2018.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): The facility passed 17 of 17 quarterly chronic toxicity tests and 4 of 4 second species tests
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performed from March 2015 to December 2018. After having neglected to perform second species testing
prior to renewal of their permit, the Permittee conducted their second species testing during the months of
August, September, October and November of 2018 under the guidance of the DWR Aquatic Toxicity
Group.
Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in 2018 reported that the facility was not in compliance. According to the summary report, deficiencies
were found with the secondary clarifier and the influent pump station. One of the secondary clarifiers was
broken but flow was still being sent through it. Black sludge was bubbling to the surface of the clarifier
and some sludge was going over the weir. At the time of inspection, the influent pump station apparently
had no functional alarms. Since the inspection was conducted, the secondary clarifier has been fixed. The
Town is currently addressing the faulty influent pump station alarms.
6. Water Quality -Based Effluent Limitations (WQBELs)
Dilution and Mixing Zones
In accordance with 15A NCAC 2B.0206, the following streamflows are used for dilution considerations
for development of WQBELs: 1 Q 10 streamflow (acute Aquatic Life); 7Q 10 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g., based on CORMLV model results): NA
If applicable, describe any mixing zones established in accordance with 15,4 NCAC 2B. 0204(b): NA
Oxygen -Consuming Waste Limitations
Limitations for oxygen -consuming waste (e.g., BOD) are generally based on water quality modeling to
ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits
(e.g., BOD-- 30 mg/l for Municipals) may be appropriate if deemed more stringent based on dilution and
model results.
Ifpermit limits are more stringent than TBELs, describe how limits were developed: NA; BOD was
deemed effluent limited per the results of a 1976 Level B model. The results of the 1976 model were
confirmed in Level B models conducted in 1984, 1990 and 1992. The limits are consistent with secondary
TBEL limits. No changes are proposed for BOD.
Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/1(summer) and 1.8 mg/1(winter). Acute ammonia limits are derived from chronic criteria,
utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 ug/1) and capped at 28 ug/1(acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/1 are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: The current
permit sets a daily maximum limit for total residual chlorine (TRC) at 28 ug I Based on the attached
wasteload allocation (WLA) review, no changes are proposed for TRC.
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While a WLA conducted in 1998 stated that ammonia limits were probably needed in the permit, monthly
average and weekly average limits for summer and winter ammonia were introduced into the permit in
2003, based on the 1998 WLA calculations and the 2003 statewide policy prompted by EPA requirements
that called for a 3:1 ratio between weekly and monthly average ammonia limits. The permit set weekly
average limits for summer and winter ammonia of 18 mg/L and 35 mg/L, respectively. It also set monthly
average limits for summer and winter ammonia of 6 mg/L and 14.7 mg/L, respectively. The ammonia
limits were reviewed in the attached WLA and are protective of ammonia toxicity. There are no proposed
changes to limits for ammonia.
Reasonable Potential Analysis [RPA] for Toxicants
If applicable, conduct RPA analysis and complete information below.
The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water quality
standards, a statistical evaluation that is conducted during every permit renewal utilizing the most recent
effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d) (i). The NC
RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2) assumption of zero
background; 3) use of/z detection limit for "less than" values; and 4) streamflows used for dilution
consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began implementation of
dissolved metals criteria in the RPA process in accordance with guidance titled NPDES Implementation of
Instream Dissolved Metals Standards, dated June 10, 2016.
A reasonable potential analysis was conducted on effluent toxicant data collected between December
2014 and December 2018. Pollutants of concern included toxicants with positive detections and
associated water quality standards/criteria. Based on this analysis, the following permitting actions are
proposed for this permit:
• Effluent Limit with Monitoring. The following parameters will receive a water quality -based
effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable
water quality standards/criteria: NA
• Monitoring Only. The following parameters will receive a monitor -only requirement since they
did not demonstrate reasonable potential to exceed applicable water quality standards/criteria,
but the maximum predicted concentration was >50% of the allowable concentration: Silver
o The Permittee shall monitor to the lowest PQL
■ Silver PQL < 1 ug/L
• No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since
they did not demonstrate reasonable potential to exceed applicable water quality
standards/criteria and the maximum predicted concentration was <50% of the allowable
concentration: Arsenic, Chromium, Cyanide, Lead, Molybdenum, Nickel, Selenium, Zinc,
Cadmium, Copper
• POTW Effluent Pollutant Scan Review: Three effluent pollutant scans were evaluated for
additional pollutants of concern.
o The following parameter(s) will receive a water quality -based effluent limit (WQBEL)
with monitoring, since as part of a limited data set, two samples exceeded the allowable
discharge concentration: NA.
o The following parameter(s) will receive a monitor -only requirement, since as part of a
limited data set, one sample exceeded the allowable discharge concentration: Bis (2-
ethylhexyl) Phthalate
o The following parameters will not receive a limit or monitoring, since they did not
demonstrate reasonable potential to exceed applicable water quality standards/criteria and
the maximum predicted concentration was <50% of the allowable concentration:
Beryllium, Total Phenolic Compounds, Fluoride
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