NC0028037_Draft Permit_20090225

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NCDENR
North Carolina Department of Environment and Natural Resou
Division of Water Quality
Beverly Eaves Perdue
Governor
Roger Spach
Water Superintendent
City of Lexington
28 West Center Street
Lexington, NC 27292
Dear Mr. Spach:
Coleen H. Sullins
Director
February 25, 2009
Subject: Draft NPDES Permit
Permit NCO028037
Lexington WTP #1 & #2
Davidson County
-Y r
RECEIVED
N.C, Deot. of ENR
FEB 2 6 2009
Winston-Salem
Regional Office
Dee Freeman
Secretary
Enclosed with this letter is a copy of the draft permit for your facility. Please review the draft very carefully to
ensure thorough understanding of the conditions and requirements it contains. The draft permit contains the
following changes from your current permit as required by the attached "DWQ- NPDES Permitting
Strategies for Potable Water Treatment Plants:
➢ Monitoring deletions
o Settleable Solids
➢ Limits added
o pH
o TRC footnote added
➢ Monitoring Additions/Chanaes
o ph, Calcium, Magnesium, Manganese, Fluoride, Total Zinc, Total Copper, Total Phosphorus
and Total Nitrogen
o Total Iron sampling changed from weekly to monthly
o Aluminum sampling changed from weekly to quarterly
o Turbidity and Total Residual Chlorine sampling changed from weekly to 2/month
o Flow sampling changed from instantaneous to continuous and recorded
➢ Whole Effluent Toxicity
o Quarterly Monitoring Purposes Only
Concurrent with this transmittal, the Division will solicit public comment on this draft as required by the EPA
by -publishing a notice in newspapers having circulation in the general Davidson County area. Please review
this draft carefully to ensure thorough understanding of the information, conditions, and requirements
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604 One
Phone: [phone] FAX: [phone] Customer Service:1-877-623-6748 NorthCarolina
Internet: www.ncwaterquality.org
�atura!!�
An Equal Opportunity 1 Affirmative Action Employer

contained therein. Should you wish to correct errors or provide comments regarding this draft please contact
the DENR / DWQ / NPDES Program no later than 30 days after receiving this document.
Following the 30-day public comment period, the Division will review all pertinent comments and take
appropriate action prior to issuing a final NPDES permit. If you have questions concerning the draft permit
for your facility, please contact me by e-mail [e-mail]) or call me at [phone].
Respectfully;
� /ice
ulie Gr b
NPDES Unit, Western Program
Enclosure: NPDES Permit NCO028037 (DRAFT)
Water Treatment Strategies Policy Document
cc: ffice / Surface Water Protection
Winston-Salem Regional Office / DEH
Aquatic Toxicology Unit
NPDES Unit
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location: 512 N. Salisbury St. Raleigh, North Carolina 27604
Phone: [phone] \ FAX: [phone] Customer Service: 1-877-623-6748
Internet: www.ncwaterquality.org
NorthCarohna
Naturally
An Equal Opportunity t Affirmative Action Employer

Permit NCO028037
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215.1, other lawful
standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, as amended,
City of Lexington
is hereby authorized to discharge wastewater from a facility located at the
Lexington Water Treatment Plant (WTP) # 1 & #2
2979 Greensboro Street Extension
Lexington
Davidson County
to receiving waters designated as Abbotts Creek in the Yadkin -Pee Dee River Basin
in accordance with effluent limitations, monitoring requirements, and other
conditions set forth in Parts I, II, III and IV hereof.
This permit shall become effective xxxx, 2009.
This permit and authorization to discharge shall expire at midnight on April 30, 2014.
Signed this day xxxx, 2009.
DRAFT
Coleen H. Sullins, Director
Division of Water Quality
By Authority of the Environmental Management Commission

Permit NC0028037
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or
discharge are hereby revoked. As of this permit issuance, any previously issued
permit bearing this number is no longer effective. Therefore, the exclusive authority
to operate and discharge from this facility arises under the permit conditions,
requirements, terms, and provisions included herein.
The City of Lexington is hereby authorized to:
Continue to operate an existing Conventional
discharge of filter backwash at 0.467
components / processes:
A Two 24-hour settling ponds
➢ Four sludge drying beds
➢ 40 X 60 foot concrete sludge st
➢ Chemical usage consisting `of-
o Aluminum sulfate(Pl,
o Ferric Chloride (Plant
o Potassium permangai
o Sodium hydroxide
o Polymers
o Sodium hypochlorite
o Sodium fluoride
o Sodium bisulfite
treatment system
MGD utilizing
with a design
the following
pad with drain line
cated at 2979 Greensboro
location specified on the
WS-III; CA waters in the

City Of Lexington Facility
Lexington WTP #1 & #2 Location
Latitude: 35° 51' 13" N State Grid: Lexington East not to scale
Longitude: 80' 11' 50" W Permitted Flow: 0.467 MGD
Receiving Stream: Abbotts Creek Stream Class: WS-III; CA Nor
NPDES Permit No. NCO028037
Drainage Basin: Yadkin -Pee Dee River Basin Sub -Basin: 03-07-07 1� Davidson County

Permit NCO028037
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge filter backwash from outfall 001. Such discharges shall be
limited and monitored by the Permittee as specified below:
EFFLUENT,
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly,;
Average
Weekly,
Averts`°e
Daily
Maximum
Measurement
Frequency
Sample Type
Sample
Location
Flow
0.467 MGD
Continuous
Recorded
Effluent
TSS
30 m L
45 m L
2./Month
Grab
Effluent
H
> 6.0 and < 9.0 standard units
2/Month
Grab
Effluent
Total Residual
Chlorines
28 µg/L
2/Month
Grab
Effluent
Turbidit3' 2
2./Month
Grab
Upstream,
Downstream
Aluminum
Quarters 3
Grab
Effluent
Calcium
Quarters 3
Grab
Effluent
Magnesium
Quarters 3
Grab
Effluent
Manganese
Quarters 3
Grab
Effluent
Fluoride
MonthlyGrab
Effluent
Total Zinc
Monthly
Grab
Effluent
Total Copper
Monthly
Grab
Effluent
Total Iron
Monthly
Grab
Effluent
Total Phosphorus
UP)
_
Quarterly3
Grab
Effluent
Total Nitrogen TN
Quarters 3
Grab
Effluent
Whole Effluent
ToxicityMonitorin 4:L
Quarterly
Grab
Effluent
Notes:
1. The Division shall consider all effluent TRC values reported below 50 ug/1 to be in compliance with
the permit. However, the Permittee shall continue to record and submit all values reported by a
North Carolina certified laboratory (including field certified), even if these values fall below 50 ug/l.
2. The discharge shall not cause the turbidity of the receiving water to exceed 50 NTU. If the turbidity
exceeds these levels due to natural background conditions, the discharge level cannot cause any increase in
the turbidity in the receiving water.
3. Parameters should be monitored in conjunction with toxicity test.
4. Chronic Toxicity (Ceriodaphnia dubia) Monitoring at 20%; January, April, July, and October
See condition A (2) of the Supplement to Effluent Limitations and Monitoring Section of this Permit.
All samples collected should be from a representative discharge event.
There shall be no discharge of floating solids or visible foam in other than trace
amounts.

Permit NCO028037
A. (2.) CHRONIC TOXICITY MONITORING (QRTRLY)
The permittee shall conduct quarterly chronic toxicity tests using test procedures outlined in the "North
Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised February 1998, or subsequent
versions.
The effluent concentration defined as treatment two in the procedure document is 20%. The testing shall be
performed as a Ceriodaphnia dubia 7day pass/fail test. The tests will be performed during the months of
January, April, July and October. Effluent sampling for this testing shall be performed at the NPDES
Permitted final effluent discharge below all treatment processes.
All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge
Monitoring Form (MR-1) for the month in which it was performed, using the parameter code TGP3B.
Additionally, DWQ Form AT-1 (original) is to be sent to the following address:
Attention: North Carolina Division of Water Quality
Environmental Sciences Section
1621 Mail Service Center
Raleigh, N.C. 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Section no
later than 30 days after the end of the reporting period for which 'the report is made.
Test data shall be complete and accurate and include all supporting chemical/physical measurements performed
in association with the toxicity tests, as well as all dose/response data. Total residual chlorine of the, effluent
toxicity sample must be measured and reported if chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the
permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the
facility name, permit number, pipe number, county, and the month/year of the report with the notation of "No
Flow" in the comment area of the form. The report shall be submitted to the Environmental Sciences Section at
the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required, then monthly
monitoring will begin immediately. Upon submission of a valid test, this monthly test requirement will revert to
quarterly in the months specified above.
Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water
Quality indicate potential impacts to the receiving stream, this permit may be re -opened and modified to include
alternate monitoring requirements or limits.
If the Permittee monitors any pollutant more frequently then required by this permit, the results of such
monitoring shall be included in the calculation & reporting of the data submitted on the DMR & all AT Forms
submitted.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control
organism survival, minimum control organism reproduction, and appropriate environmental controls,
shall constitute an invalid test and will require immediate follow-up testing to be completed no later than
the last day of the month following the month of the initial monitoring.

DENR/DWQ
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NC0028037
Lexington WTP No.1 and No. 2
Permittd'Flow dei "`
0.467 MGD
County <,`. ,
Davidson t°
Factll "Class� ,,. „ �: _
I
Re onal'Office��;�-. a
Winston-Salem
Faexlity/Perrnit Status.,,.
Modification;
Existin
Renewal
USGS Topo
n u {
v
D18SW
Stream Characteristics
Reeeivix' ,Stxearn., "
Abbotts Creek
Streazxt Class fieatiofi
WS-III; CA
Winter.7QW (cfs):
14 BIMS 2009
Subbasiri �. _ ..
03-07-07
30.>. (ds):a;# �...�, : �. � .�-
N/A
.;. 2 :-
Drainage Area; ('rm
N/A
Average Flow (cfs): r
N/A
Summer7.Qf0cfs)''"` '
2.9 BIMS 2009IWC
(�/o): ' =' , _
20
Changes Incorporated into Permit Renewal
Pro osed Chan es
P,akameters Affected
Basis'for` chan
Remove Monitoring for
Settleable solids
2007 WTP Strategy
Settleable Solids
Add Monitoring for the
pH
2O07 WTP Strategy for all parameters.
following parameters
Calcium
Fluoride - facility uses fluoridated
Magnesium
finished water to backwash.
Manganese
Zinc - facility uses zinc
Fluoride
orthophosphate as a corrosion
Total Zinc
inhibitor.
Total Copper
Chloramine in not used so ammonia
TP and TN
monitoring was not added.
WET — Chronic at 20%
Change sampling frequency
Aluminum
Reduce to quarterly per WTP Strategy
Iron:
Reduce to monthly per WTP Strategy
TRC
Reduce to 2/month per WTP Strategy
Flow
Change from instantaneous to continuous per
WTP strategy
TRC footnote — Compliance
TRC
Changed per Matt Matthew's memo
level changed to < 50 u 1
dated 5/l/08.
Summary
Facility has submitted an application for renewal with no identified changes to facility operations.
The facility discharges into Abbotts Creek. This creek has documented water quality problems
but in this particular section the aquatic life use support is not rated because of inconclusive data.
Parameter of interest is chlorophyll a. Abbotts Creeks flows into High Rock Lake which is
impaired for High ph and chlorophyll a'.t was stated that no new dischargers of oxygen
consuming wastes be permitted in the Abbotts Creek watershed. In addition, nutrient
loading from the major facilities in this subbasin have heavily impacted the Abbotts
Creek arm of High Rock Lake. A TMDL is to be established for TP and TN for facilities
discharging into this watershed.

DENR/DWQ
FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No. NCO028037
(Continued)
Stream Class:
Abbotts Creek
WS-III; CA
12-119-(4.5)
2008 Basin Plan
• 303(d) List Review: This section of Abbotts Creek is not listed on North Carolina's
2008 303(d) List.
• Review of Basin Plan: This facility was previously listed under 12-119(1) Abbotts
Creek. The facility is actually in 12-119-(4.5) or at the top section of 12-119-(6)a.
12-119-(4.5) does not have a use support rating for aquatic life because the data was
inconclusive. 12-119-(6)a is aquatic life impaired for turbidity and
ecologicalibiological integrity and benthos.
• Staff Report (most recent was 1993): Facility is classified as Class I. The
discharge consists of supernatant drawn off from either of the two 0.35 MGD settling
basins. The basins receive filter backwash and basin wash water. Solids collected in
the settling basins and are periodically pumped onto the drying beds for disposal in
the county landfill.
• Compliance and DMR Review:
Facility appears to be operating within the constraints of their existing discharge
permit. No violations are noted except for TRC which is below 50 ug/l. The last
inspection was performed on 2-6-08 by Jenifer Carter (WSRO) rating it as a good
inspection overall.
• Permit Limits:
The summer 7Q10 was taken from BIMS which was listed as 2.9 cfs. This number
appeared reasonable compared to the closest USGS gage (02121500) 2 miles
downstream. An IWC (%) of 20 % was established and the TRC limit was capped at
28 ug/l. Turbidity is not regulated as part of the 2007 WTP strategy but was left in
the permit due to the impaired nature of Abbotts Creek below the WTP (12-119-(6)a)
for turbidity.
Proposed Schedule for Permit Issuance
Draft Permit to Public Notice: 2/25/09
Permit Scheduled to Issue: 5/l/09
State Contact
If you have any questions on any of the above information or on the attached permit,
please contact Julie Grzyb at (919) 807 -6389.