NC0021407_Speculative Limits_20020814

NPDES DOCUMENT SCANNING COVER SHEET
NC0021407
Highlands WWTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
August 14, 2002
'Mulls document is printed on reuse paper - iggnore any
content on the reizeriae side

State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Alan W. Klimek, P.E., Director
Mr. Richard Betz
Town Administrator
P.O. Box 563
Highlands, North Carolina 28741
arA
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
August 14, 2002
Subject: Speculative Limits for the Town of Highlands
NPDES Permit NC0021407
Highlands WWTP
Macon County
Dear Mr. Betz:
The Town of Highlands requested speculative limits for an expanded discharge of 1.5 MGD to the Cullasaja
River. The Division of Water Quality has reviewed the request and provides the following response.
The speculative limits presented here are based on our understanding of the proposal and of present
environmental conditions. The Division of Water Quality (DW(2) cannot guarantee that it will issue the Town an
NPDES permit at the expanded flow rate. Nor can we guarantee that the effluent limitations and other
requirements included in any permit will be exactly as presented here. Final decisions on these matters will be
made only after the Division receives and evaluates a formal permit application for the Town's proposed
discharge.
Environmental Assessments of New Projects
Please be aware that the Town of Highlands will have to evaluate this project for environmental impacts before
receiving a modified permit. Anyone proposing to construct new or expanded waste treatment facilities using
public funds or public (state) lands must first prepare an Environmental Assessment (EA) when wastewater flows
(1) equal or exceed 0.5 MGD or (2) exceed one-third of the 7Q10 flow of the receiving stream. DWQ will not
accept a permit application for a project requiring an environmental assessment until the Division has approved
the EA and sent a Finding of No Significant Impact (FONSI) to the state Clearinghouse for review and comment.
If an Environmental Assessment is required, it should contain a clear justification for the proposed facility. It
should provide an analysis of potential alternatives, including a thorough evaluation of non -discharge
alternatives. Nondischarge alternatives or alternatives to expansion, such as spray irrigation, water conservation,
inflow and infiltration reduction or connection to a regional treatment and disposal system, are considered to be
environmentally preferable to a surface water discharge. In accordance with the North Carolina General Statutes,
the preferred alternative must be the practicable waste treatment and disposal alternative with the least adverse
impact on the environment is required to be implemented. If the EA demonstrates that the project may result in a
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Speculative NPDES Limits
Town of Highlands
NPDES NC0021407
significant adverse effect on the quality of the environment, you must then prepare an Environmental Impact
Statement. Todd Kennedy of the Water Quality Planning Branch can provide additional information regarding
the requirements of the N.C. Environmental Policy Act. You can contact Mr. Kennedy directly at [phone],
ext. 555.
Speculative Effluent Limits
The winter 7Q10 flow has been updated. The winter 7Q10 flow used during the previous permitting cycle was
based on and an analysis of flow records from 1971 through 1983 and included the influence of the hydroelectric
facility. Since the hydroelectric facility has been shutdown for sometime, the winter 7Q10 flow calculated during
the previous permitting cycle is no longer accurate. Therefore, the United States Geological Survey (USGS)
recalculated the winter 7Q10 flow and based on preliminary results, the winter 7Q10 flow has been revised to 7.45
cfs. Even though the winter 7Q10 has been updated, the flow having the greatest influence on permit limitations
continues to be the summer 7Q10. The summer 7Q10 flow remains unchanged since the previous permitting
cycle (confirmed by USGS).
Based on the available information, tentative limits for a proposed expansion of the discharge to 1.5 MGD to the
Cullasaja River are presented below.
Effluent Limits for 1.5 MGD
Flow (MGD) 1.5
BOD5 — Monthly Average (mg/L) 30.0
BOD5 — Weekly Average (mg/L) 45.0
NH3-N (Summer) — Monthly Average (mg/L) 3.4
NH3-N (Summer) — Weekly Average (mg/L) See Text
NH3-N (Winter) — Monthly Average (mg/L) 6.7
NH3-N (Winter) — Weekly Average (mg/L) See Text
Total Suspended Residue — Monthly Average (mg/L) 30.0
Total Suspended Residue — Weekly Average (mg/L) 45.0
Dissolved Oxygen (mg/L) 5.0
Fecal Coliform — Monthly Average (#/100 mL) 200
Fecal Coliform — Weekly Average (#/100 mL) 400
pH (S.U.) 6.0 — 9.0
Total Residual Chlorine (ug/L) 22
Chronic Toxicity Pass/Fail @ 24.4% with Ceriodaphnia Dubia
Flow Limits. The flow will be limited to 1.5 MGD as requested by the consultant. This limit will be applied as a
monthly average.
BODs;. The limits for these parameters were based on the waste assimilating capacity of the receiving stream at
low flow conditions. The limitations presented here are based on the results of a one dimensional dissolved
oxygen model. Based on the results of this modeling effort, secondary treatment limits will protect North
Carolina's instream dissolved oxygen standard in the Cullasaja River.

Speculative NPDES Limits
Town of Highlands
NPDES NC0021407
NH3-N. Ammonia was evaluated for both dissolved oxygen depletion and toxicity. The limits for ammonia are
based on protection of the instream toxicity and North Carolina's instream ammonia criteria. These speculative
limits currently contain only monthly average limits for ammonia. The Division is currently evaluating an
appropriate weekly average limit for all discharges in North Carolina. The current schedule is to complete this
evaluation by September 30, 2002. At that time, the Division will begin requiring both monthly and weekly
average limits for ammonia.
Total Suspended Solids. The limits for total suspended solids are standard for secondary treatment of municipal
wastewater.
Fecal Coliform, pH. The limits for fecal coliform bacteria and pH are derived to protect water quality in the
receiving stream and remain the same as the existing permit. The fecal coliform limit is based on a geometric
mean.
Total Residual Chlorine (TRC). In North Carolina, waters designated as trout waters have a TRC standard. Since
the Cullasaja River is designated as trout water, a limit for total residual chlorine is included for protection of the
TRC standard.
Chronic Toxicity Testing. Chronic pass/fail toxicity testing at 24.4% with Ceriodaphnia Dubnia will be required
in the NPDES permit for a wasteflow of 1.5 MGD. Quarterly monitoring will be required. The Division of Water
Quality requires toxicity testing for major discharges. Since major is defined as greater than or equal to 1 MGD of
wasteflow, at the expanded flow the facility will be considered a major discharger and a toxicity limit is required.
Dissolved Oxygen. Limits for dissolved oxygen are based on protection of North Carolina's standard.
Nutrients: Total Phosphorus, Total Nitrogen. No limits for nutrients are recommended at this time. However, if
future instream assessments indicate that the accumulation of nutrients are creating eutrophication problems,
nutrient limits may be added to the permit.
The Division of Water Quality will perform a complete evaluation of limits and monitoring requirements for
metals and other toxicants when we review the Town's formal permit application.
I trust this response offers sufficient guidance for the County's proposed treatment plant. If you have any
additional questions about these limits, feel free to contact Michael Myers at [phone], extension 508.
Sincerely, /
David A. Goodrich
Supervisor, NPDES Unit
cc: Asheville Regional Office - Division of Water Quality
CalIie Dobson - Division of Water Quality, Planning Branch
Todd Kennedy - Division of Water Quality, Planning Branch
Central Files
`ISTP M511iiiffiks,

' 08/ 03/ 2001 09:30
2
4
PAGE 01
oc- vim
co
0
es,
WiIlium G. Ross Jr.. Secretary
North Carolina Department of EnVironment and Natural Resources
Gregory J. i norpe, rn.u.
Acting Director
Division) of Water quality
rowh
Memorandum
lDate: August 3, 2001
To: Dave Goodrich, NPDES Permitting
1'rcym: Kevin Barnett, AR4
Subject: Waste Load Allocation Request for the Town of Highlands
Attached, please find the request for a waste load allocation for the Town of Highlands. Please let me know if
you need anything from me.
Kevin
N. C. Division of Water Quality 1617 Moll Service Center Raleigh, NC 27699-1617
[phone]
Customer Service
1 800 623-7148

08/03/2001 09:30 4 PAGE 02
W �{ JAI d.. C
DICKSCJN ;
JUL'-u
I
July 20, 2001
Mr. Forest Westall, PE
North Carolina Department of Environment
and Natural Resources
59 Woodfin Place
Asheville, North Carolina 28801
RE: Waste -Load Allocation Request
for the Town of Highlands
Wastewater Treatment Plant Expansion
WKD #00774.40
Macon, North Carolina
Dear Mr, Westall:
QUALITY
•_I-- FEGIQi'!
We are working with the Town of Highlands to expand their existing wastewater
trootment plant capacity to 1.5 MGD. The existing plant has a capacity of 0.5
MGO. The effluent is discharged into the Culiasaja River immediately below the
Lake Sequoyah Dam, as shown in the attached figure. The facility operates
under the NPDES permit number NC0021407.
We are requesting a preliminary waste -load allocation, effluent limitations and
monitoring requirements for the expansion so that we may complete the
alternatives analysis for this project. The wastewater is primarily domestic in
nature and will remain so.
If you have any questions, or require additional information, do not hesitate to
call.
Sincerely,
W. K. Dickson & Company, Inc.
Victor Lofquis ,
Enclosures
cc: File, Richard Betz, Town Administrator
.4JH.JS I.1(111
I N( 828.251.1611
www wkdukson.com
Allan la. UA
Charlollc. NC
Hickory, Nc
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State of North Carolina
Department of Environment
and Natural Resources
Division of Water Quality
Michael F. Easley, Governor
William G. Ross, Jr., Secretary
Alan W. Klimek, P.E., Director
June 12, 2000
MEMORANDUM
To:
From:
File
Michael J. Myers lir--
NPDES Unit
Subject: Speculative Effluent Limits
Highlands WWTP
Macon County
A7A
NCDENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
July 31, 2002 — Contacted USGS.
Verified s7Q10 flow is 7.2 cfs
USGS indicated that the w7Q10 in 1995 was based on an examination of records from 1971 —1983
and included the influence of the hydro facility. Since the hydro facility has been shut down for quite sometime
the w7Q10 is no longer valid.
The USGS recalculated the w7Q10 using the appropriate regression equations (as reported in the
Low Flow Characteristics) and reported that the w7Q10 is equal to 20 cfs. The USGS also compared yields from
similar drainage areas and found yields ranged from 0.5 —1.0 cfs/mile2. Assuming the low end yields (0.5
cfs/mi2) the w7Q10 was again recalculated and compared to the regression equations w7Q10 — 7.45 cfs (yield
method)
Model Inputs — Flow = 1.5 MGD
CBOD = 45.0 mg/L (assumes CBOD/BOD = 1.5)
NBOD = 15.4 (based on ammonia toxicity limitation of 3.42 mg/L)
S7Q10 = 7.2 cfs
W7Q10 = 7.45 cfs
Existing Limitations —
Flow = 0.5 MGD
TSS = 30/45 mg/L
NH3-N summer = 8.3 mg/L
NH3-N winter = 20 mg/L
Fecal Coliform = 200/400 per 100 ml
TRC = 22 ug/L
DO = 5.0 mg/L
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Sep 21 01 10:14a WKD Registered User
828 251-1611
p.4
ri'
DiCK
July 20, 2001
Mr. Forest Westall, PE
North Carolina Department of Environment
and Natural Resources
59 Woodfin Place
Asheville, North Carolina 28801
RE: Waste -Load Allocation Request
for the Town of Highlands
Wastewater Treatment Plant Expansion
WKD #00774.40
Macon, North Carolina
Dear Mr. Westall:
We are working with the Town of Highlands to expand their existing wastewater
treatment plant capacity to 1.5 MGD. The existing plant has a capacity of 0.5
MGD. The effluent is discharged into the Cullasaja River immediately below the
Lake Sequoyah Dam, as shown In the attached figure. The facility operates
under the NPDES permit number NC0021407.
We are requesting a preliminary waste -load allocation, effluent limitations and
monitoring requirements for the expansion so that we may complete the
alternatives analysis for this project. The wastewater is primarily domestic in
nature and will remain so.
If you have any questions, or require additional information, do not hesitate to
call.
Sincerely,
W. K. Dickson & Company, Inc.
Victor Lofquist', 1'E
Enclosures
cc: File, Richard Betz, Town Administrator

SUMMER
MODEL RESULTS
Discharger : TOWN OF HIGHLANDS
Receiving Stream : CULLASAJA RIVER
The End D.O. is 8.37 mg/1.
The End CBOD is 13.70 mg/l.
The End NBOD is 4.21 mg/l.
WLA WLA WLA
DO Min CBOD NBOD DO Waste Flow
(mg/1) Milepoint Reach # (mg/1) (mg/1) (mg/1) (mgd)
Segment 1 7.06 0.00 1
Reach 1 45.00 15.40 5.00 1.50000
Reach 2 0.00 0.00 0.00 0.00000

*** MODEL SUMMARY DATA ***
Discharger
Receiving Stream .
Summer 7Q10
Design Temperature:
LENGTH
mile
TOWN OF HIGHLANDS
CULLASAJA RIVER
7.2
23.0
SLOPE
ft/mi
VELOCITY
fps
DEPTH
ft
Subbasin : 040401
Stream Class: B-TR
Winter 7Q10 : 7.45
Kd
design
Kd Idesign
Ka @20°
Ka
@20°
KN
design
Segment 1
Reach 1
0.30
352.00
0.882
0.85
0.94
0.82
53.37
50.00
0.63
Segment 1
Reach 2
0.60
62.00
0.537
1.09
0.57
0.49
53.37
50.00
0.63
Flow
cfs
Segment 1 Reach 1
Waste 2.325
Headwaters 7.200
Tributary 0.000
* Runoff 0.200
Segment 1 Reach 2
Waste
Tributary
* Runoff
0.000
0.000
0.200
CBOD
mg/1
45.000
5.000
2.000
2.000
0.000
2.000
2.000
* Runoff flow is in cfs/mile
mB„-Ih
NBOD D.O.
mg/1 mg/1
15.400
1.000
1.000
1.000
0.000
1.000
1.000
5.000
7.720
7.720
7.720
0.000
7.720
7.720
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SUMMER
Seg # I Reach # I Seg Mi I D.O. 1 CBOD 1 NBOD 1 Flow
1 1 0.00 7.06 14.76 4.51 9.53
1 1 0.05 7.26 14.70 4.50 9.54
1 1 0.10 7.43 14.64 4.49 9.54
1 1 0.15 7.57 14.58 4.47 9.55
1 1 0.20 7.69 14.52 4.46 9.56
1 1 0.25 7.79 14.46 4.45 9.57
1 1 0.30 7.87 14.40 4.43 9.58
1 2 0.30 7.87 14.40 4.43 9.58
1 2 0.35 8.00 14.34 4.42 9.59
1 2 0.40 8.10 14.28 4.40 9.60
1 2 0.45 8.17 14.22 4.38 9.61
1 2 0.50 8.23 14.16 4.36 9.62
1 2 0.55 8.27 14.10 4.34 9.63
1 2 0.60 8.30 14.05 4.32 9.64
1 2 0.65 8.32 13.99 4.30 9.65
1 2 0.70 8.33 13.93 4.28 9.66
1 2 0.75 8.35 13.87 4.26 9.67
1 2 0.80 8.35 13.82 4.24 9.68
1 2 0.85 8.36 13.76 4.23 9.69
1 2 0.90 8.37 13.70 4.21 9.70
Seg # I Reach # I Seg Mi I D.O. I CBOD I NBOD I Flow
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