NC0032719_Technical Correction_20100208

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NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H.Sullins Dee Freeman
Governor Director Secretary
February 8, 2010
Mr. Luther C. Copeland, County Manager
Chowan County Water Department
P.O. Box 1030
Edenton, North Carolina 27932
Subject: Technical Correction to NPDES Permit
Permit No. NCO032719
Valhalla WTP
Chowan County
Dear Mr. Copeland:
After review by the Division it was determined that the Valhalla WTP effluent qualifies for the Acute Toxicity
monitoring test. As a technical correction to your existing permit, we are issuing only the pages in your permit that
are affected from the change of your toxicity monitoring to an acute toxicity pass/fail test using 90% effluent with
fathead minnows. The instream sampling requirements have been corrected to require only sampling of the pond
overflow.
Please insert the new pages into your existing permit and discard the replaced pages. This does not change any
other term, limits or conditions in your existing permit, or the relaxed Total Chloride limit covered by your SOC. The
acute toxicity test and pond overflow sampling becomes effective upon receipt of these pages.
Any planned physical changes to your facility operation or wastewater discharge configuration must be
reviewed by the Washington Regional Office/Surface Water Protection. If you have any questions about this correction
contact Ron Berry at [phone] or email [e-mail].
Sincerely,
Ron Berry
NPDES Group
Attachments
cc: Washington Regional Office/Surface Water Protection (email)
Environmental Sciences Section/Aquatic Toxicology Unit/Susan Meadows (email)
Central Files
NPDES Unit
1617 Mail Service Center,Raleigh,North Carolina 27699-1617
Location:512 N.Salisbury St.Ralegh,North Carolina 27604 One
Phone:[phone] t FAX:[phone] Customer Service:1-877-623-6748 NorthCar©hna
Internet: ttp:ppo t 1 h2o.e Affirmative us
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NCO032719
A (1). EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge from outfall(s) serial number 001. Such discharges shall be limited and monitored by
the Permittee as specified below:
EFFLUENT LIMITS __. MONITORING REQUIREMENTS
_.
CHARACTERISTICS Monthly Weekly Daily Measurement Sample Sample
Average Average Maximum Frequency Type Location}
Flow 0.060 MGD Monthly Instantaneous 2 E
Total Suspended Solids 30.0 mg/L 45.0 mg/L 2/Month Grab E
(TSS)
Total Residual Chlorine
(TRC) s 17 Ng/L 2/Month Grab E
Total Chloride 230 mg/L 2/Month Grab E
pH Not more than 9.0 S.U. nor less than Monthly Grab E
6.0 S.U.
pH, S.U. Monthly Grab D
Temperature, °C Monthly Grab E
Temperature, °C Monthly Grab D
Dissolved Oxygen, mg/L Monthly Grab E
(DO)
Dissolved Oxygen, mg/L
(DO) Monthly Grab D
Salinity, ppt Monthly Grab E
Salinity, ppt Monthly Grab D
Conductivity, pohms/cm Monthly Grab E
Conductivity, pohms/cm Monthly Grab D
Total Copper, mg/L Monthly Grab E
Total Iron, mg/L Monthly Grab E
Total Manganese, Ng/L Monthly Grab E
Ammonia as Nitrogen, mg/L Monthly Grab E
Total Nitrogen, mg/L(TN) Monthly Grab E
Total Phosphorus, mg/L Monthly Grab E
(TP)
Whole Effluent Toxicity a Quarterly Grab E
Notes:
1. Sampling locations: E= Effluent, D=overflow from pond.
2. For instantaneous flow monitoring, the duration of the discharge must be reported in addition to the total flow.
3. Limit takes effect November 1, 2008. Limit and monitoring requirement only apply if chlorine is used for
disinfection. The facility shall report all effluent TRC values reported by a NC certified laboratory including field
certified. However, effluent values below 50 pg/L will be treated as zero for compliance purposes.
4. Acute Toxicity (Pimephales promelas) 24 hour Static P/F monitoring test at 90.0% effluent concentration during
the months of February,May,August, and November. See Special Condition A(2).
All samples collected should be of a representative discharge.
There shall be no discharge of floating solids or foam visible in other than trace amounts.
A (2). ACUTE TOXICITY MONITORING (QUARTERLY)

NC0032719
The permittee shall conduct acute toxicity tests on a quarterly basis using protocols defined in the North
Carolina Procedure Document entitled "Pass/Fail Methodology For Determining Acute Toxicity In A Single
Effluent Concentration" (Revised-July, 1992 or subsequent versions). The monitoring shall be performed as a
Fathead Minnow (Pimephales promelas) 24 hour static test. The effluent concentration at which there may be
at no time significant acute mortality is 907o (defined as treatment two in the procedure document). Effluent
samples for self-monitoring purposes must be obtained during representative effluent discharge below all waste
treatment. The tests will be performed during the months of February, May, August, and November.
The parameter code for Pimephales promelas is TGE6C. All toxicity testing results required as part of this
permit condition will be entered on the Effluent Discharge Form (MR-1) for the month in which it was
performed, using the appropriate parameter code. Additionally, DWQ Form AT-2 (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 any month, 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 any test data from either these monitoring requirements 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 It reporting of the data submitted on the DMR ft all AT Form
submitted.
NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism
survival and appropriate environmental controls, shall constitute an invalid test and will require immediate
fallow-up testing to be completed no later than the last day of the month following the month of the initial
monitoring.