NC0021890_speculative limits_19970224

NPDES DOCUMENT SCANNING COVER SHEET
NPDES Permit: NC0021890
Granite Falls WWTP
Document Type: Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Staff Report
Instream Assessment (67b)
Speculative Limits}
Environmental Assessment (EA)
Document Date: February 24, 1997
Thia document is printed on reuae paper-ignore any
content on the res% Brae aide

State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Water Quality
James B. Hunt, Jr., Governorgyp`
Jonathan B. Howes, Secretary H N F1
A. Preston Howard, Jr., P.E., Director
February 24, 1997
The Honorable A.W. Huffman Jr.
Town of Granite Falls
P.O. Box 10
Granite Falls, N.C. 28630-0010
Subject: Speculative Limits for Caldwell Co. Dischargers
Dear Mayor Huffman:
An analysis for speculative effluent limits for the expansion of several facilities in
Caldwell County has been completed by the staff of the Insneam Assessment Unit. These
limits were rcduested in lieu of an area-wide 201 Facilities Plan Amendment For the US 321
Corridor fi om Lake Hickory to Lenoir. Speculative limit., were prepared for wastewater
trcaunent plants for the Lenoir- Lower Creek and Gunpowder Creek facilities, Granit.,
Falls W WTP and a proposed regional W W'rP downstream of the existing Granite Falls
plant.
Pleasc be advised that response to this request does not guarantee that the Division
will issue NPDES permits to discharge treated wastewator into these receiving waters. It
should he noted that the. preparation of an environmental assessment (EA) by the applicant
will he required in the following cases: 1) a �w facility involving an ,expenditure of puhlic
funds or use of public (state) lands and having a design capacity of0.5 MGD or greater and
2) a facility proposing an expansion of 0.5 MGD or greater, or exceeding one-third of the.
7Q10 of the receiving sueam.
DWQ will not accept a permit application for a project requiring an EA until the
document has been approved by the Department of Environment, Health and Natural
1kCS0W'ceS and a Finding of No Significant Impact (FONSI) has been sent to the State.
C'Icmin�,house for review and comment_ The EA showJ contain a clearjustification for the
propos: d facility and an analysis of potential alm naw Mitch should include, a thorou'01
evaluation of non-discharge ,ItCrnatiVCS.
In addition. an EA <hould show Low water 1'euW, conscn anon, and
inflow/infiltration reductions have been considered. Nondischail_�e Atornativos, such as
Spray lrllgation, water Conservation, inflow and infiltration redni;1,1011 Or C0nooCtli)n to ❑
n11010nal treanncnt and disposal system, an, considered to he c:nvirunmenlall}- preferahlc to a
surl'tce water discharge. ]n ac,o 1,mcc with the North Carolina Gent :ai Statute::, tho
praclicable waste ucatment and a',s!) lsal ahcrnativc with the least adverse impact on the.
cn,viri nincm is ru;uircd to he implemented. If the EA demonstrates that the project may
rrsult in a significant adverse affect on the ,Iuality of the ormi-onmenm, an Environmental
il.,pact Statement (EIS) would he required. Michelle S:rvcrlo'uhhc' of the Water Quality
Planning Branch can provide furthol inforination regarding the rcgnircments of the 1,1.C.
Environmental Policy Act.
P.O Rox 29535, Raleigh, Ncrth Carolina 27626-0535 Telephone [phone] FAX [phone]
,',o Equal Opportunity Affirmative Action Employs,r paper

t
Letter to Mayor Huffman
- page 2 -
In order to receive final permit limits, a formal application will have to be submitted
to the Division's Permits and Engineering Unit. Per North Carolina's anti-degradation
policy (15A NCAC 2B.0201 (c)(1)), each application for an NPDES permit or.NPDES
permit expansion to discharge treated waste will require documentation of an effort to
consider non-discharge alternatives pursuant to North Carolina Regulation 15A NCAC
2H.0105 (c)(2).
'Based on available information, the tentative limits for conventional constituents for
the Lenoir- Lower Creek WWTP at the expansion flow of 6 MGD are:
Summer Winter
BOD5 (mg/1) 22 30
NH3-N(mg/1) 2 4.6
TSS (mg/1) 30 30
Dissolved Oxygen (mg/1) 5 nr
Fecal Coliform (#/100ml) 200 200
pH (SU) 6-9 6-9
Chlorine (µg/l) 28 28
*nr- no requirement
The instream waste concentration at 6.0 MGD is 44%. A chronic toxicity testing
requirement with quarterly monitoring will remain a condition of the NPDES permit. A
complete evaluation of limits and monitoring requirements for metals and other toxicants
will be addressed for all the expansion flows at the time of formal permit application.
The tentative limits for conventional constituents for the Lenoir- Gunpowder Creek
WWTP at the expansion flow of 3.2 MGD are:
L� Summer Winter
BOD5 (mg/1) 22 30
NH3-N (mg/1) 2 4
TSS (mg/1) 30 30
Dissolved Oxygen (mg/1) r 5 nr
Fecal Coliform (#/100ml) 200 200
pH (SU) 6-9 6-9
Chlorine (µg/l) 26 26
The instream waste concentration at 3.2 MGD is 63%. A chronic toxicity testing
requirement with quarterly monitoring will remain a condition of the NPDES permit.
Instream.monitoring for the parameters, temperature, dissolved oxygen, and conductivity,
will still be,required. In addition, it is recommended that instream nutrient monitoring for
total nitrogen, total phosphorus, and chlorophyll a, be continued during the months of May
through September.

i .
Letter to Mayor Huffman
- page 3 -
The tentative limits for conventional constituents at the Granite Falls WWTP at the
two proposed flows are as follows:
Summer Winter
Wasteflow-(MGD) 1.9 1.9
BOD5 (mg/1) 11.8 18.8
NH3-N (mg/1) 2.9. 7.4
TSS (mg/1) 30 30
Dissolved Oxygen (mg/1) 5 nr
Fecal Coliform (#/100m1) 200 200
pH (SU) 6-9 6-9
Chlorine (µg/1) 28 28
Summer Winter
Wasteflow (MGD) 2.7 2.7
BODS (mg/1) 8.3 12.9
NH3-N (mg/1) 2.4 5.7 6
TSS (mg/1) 30 30
Dissolved Oxygen (mg/1) 5 nr
Fecal Coliform (#/100rn1) 200 200
pH (SU) 6-9 6-9
Chlorine (µg/1) 28 28
The instream waste concentrations at 1.9 and 2.7 MGD are 29% and 36%,
respectively. A chronic toxicity testing requirement with quarterly monitoring will remain a
condition of the NPDES permit.
The final speculative scenario was�, roposed regional facility with design flows of
3 or 6 MGD, that would discharge near thclhfouth of Gunpowder Creek just before its
confluence with Lake Hickory. Information provided to DWQ indicated that this regional
facility would allow both the Gunpowder Creek and Granite Falls WWTPs to go.off-line
and connect to this plant. Because there is ve 1fy little slope and the receiving stream is a
cove like area, this discharge at the mouth of'Ounpowder Creek would be considered a
direct discharge to Lake Hickory. It is recommended that this proposed facility be
designed to meet advanced secondary limits for conventional constituents. For planning
purposed, it recommended that the plant be designed to meet limits of between 15 to 20
mg/1 BODS�vnd 2 to 6 mg/l NH3-N. In addition, tentative limits for non oxygen
consuming wastes are:
DO (mg/l) 5
TSS (mg/1) 30
'Fecal Coliform (#/100ml) 200
pH (SU) 6-9
Chlorine (µg/l) 28
Currently, the US Geological Survey, the Western Piedmont Council of
Government(WPCOG) and DWQ are conducting a water quality study to estimate the
assimilative capacity of Lake Hickory for oxygen consuming wastes. Since the study is
still ongoing, no definitive recommendations have been presented. Until that study is
completed and water quality modeling results are finalized, the Technical Support Branch

a
Letter to Mayor Huffman
- page 4-
recommends that the proposed facility be designed to meet advanced secondary limits with
sufficient flexibility so as to be able to meet BOD5 limits and NH3-N limits in the ranges
described above.
The BOD5 and NH3 limits were recommended using DWQ's Best Professional
Judgment(BPJ) in an effort to help reduce the impact of point sources discharging directly
into the major lakes in the Catawba River Basin. With existing stages of eutrophication and
documented water quality problems in Lakes Wylie, Rhodhiss, Hickory and other tributary
arms above lakes, DEM does not recommend continuing with the minimum level of
wastewater treatment for direct discharges to lakes. Therefore, BPJ limits will be applied
to all new and expanding discharges to the Catawba chain lakes.
Nutrient loading can cause water quality problems in lakes. For the expanding
WWTPs at Lenoir-Gunpowder Creek, Granite Falls and the proposed Gunpowder Creek
discharger near the mouth, it is recommended that the treatment plants be designed so that
they can be easily upgraded for nutrient removal. This would be a proactive measure, in the
event that water quality studies show that nutrient limits, particularly for total phosphorus,
are necessary in the future.
It should be noted that the summer and winter NH3-N limits recommended for all
these plants are based on protecting the receiving streams against instrearn toxicity. North
Carolina is evaluating all NPDES dischargers for arnmonia toxicity following the
Environmental Protection Agency (EPA) guidance to protect the waters for an instream
criteria of 1 mg/1 in the summer and 1.8 mg/1 in the winter, under 7Q10 flow conditions.
The Division of Water Quality (D)k ) is requiring chlorine limits and
dechlorination for all new or expanding disc argers proposing the use of chlorine for
disinfection. The process of chlorination/dechlorination or an alternate form of
disinfection, such as ultraviolet radiation, should allow the facility to comply with the total
residual chlorine limits recommended in the'aove scenarios.
The request did not indicate whether any of the expansion wastewater would have
any industrial constituency, therefore this aspect could not be evaluated. If there is any
industrial flow, there is the possibility that effluent limitations or monitoring for toxicants
or metals could be added to the permits upon further evaluation.
DWQ is currently on its second round of implementation of a basinwide water
quality management initiative for the Catawba River Basin. 'Our next installment of the
Catawba River Basin plan is scheduled for publication in the year 2000 . We will attempt
to further address all sources of point and nonpoint pollutants where deemed necessary to
protect or restore water quality standards. In addressing interaction of sources, wasteload
allocations may be affected. Those facilities that already have committed to high levels of
treatment technology are least likely to be affected.

Letter to Mayor Huffman
-page 5-
Final NPDES effluent limitations will be determined after a formal permit
application has been submitted to the Division. If there are any additional questions
concerning this matter, please feel free to contact Ruth Swanek (ext. 503) or Jackie Nowell
(ext. 512), of my staff at [phone].
i1 eerely,
onald L. S . it P E.
Assistant Chief fo Technic S pport
Water Quality Section
DLS/JMN
cc: Rex Gleason
Tim Baldwin, McKim and Creed
Mike Waresak, McGill and Associates
Central Files
WLA File