NC0024945_Monitoring (Information)_20201119

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
Ms. Jacqueline A. Jarrell, P.E.
Operations Chief
Environmental Management Division
Charlotte Water
5100 Brookshire Blvd.
Charlotte, North Carolina 28216
Dear Ms. Jarrell:
NORTH CAROLINA
Environmental Quality
November 19, 2020
Subject: Chronic Toxicity Test Results
Irwin Creek WWTP
NPDES Permit No. NCO024945
Mecklenburg County
Enclosed is a copy of the toxicity test results relative to the samples collected (split) at the subject facility on October 27
and 29, 2020, by Charlotte Water staff and Mr. Wes Bell of this Office. Effluent samples were collected for use in a chronic
Ceriodaphnia dubia pass -fail toxicity test. The test Passed utilizing these samples. Please inform the facility's Operator -in -
Responsible Charge (ORC) of our findings by forwarding a copy of the enclosed report.
The report should be self-explanatory; however, should you have any questions concerning this report, please do
not hesitate to contact Mr. Bell at [phone] or at [e-mail].
Sincerely,
DocuSigned by:
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W. Corey Basinger, Regional Supervisor
Water Quality Regional Operations Section
Division of Water Resources, DEQ
Enclosure:
Toxicity Test Results
�� Office
Carolina Department of Environmental Quality I Division of Water Resources
Mooresville Regional 1 610 East Center Avenue, Suite 301 1 Mooresville, North Carolina 28115
NOR7H ORROLINA i
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Division of Water Resources
November 16, 2020
MEMORANDUM
To: Corey Basinger
Water Quality Regional Opera ' ns, MRO
Through: Cindy A. Moore
Supervisor, Aquatic Toxicology Branch (ATB)
From: Lorimar S. Henning Ap
Environmental Specialist II, Aquatic Toxicology Branch (ATB)
Subject: Whole effluent toxicity test results
CMUD-Irwin Creek WWTP
NPDES Permit # NC0024945/001
Mecklenburg County
The aquatic toxicity test using flow -proportional composite samples of effluent discharged from
the CMUD-Irwin Creek WWTP has been completed. CMUD-Irwin Creek WWTP has a permitted
effluent discharge of 15.0 million gallons per day (MGD) entering Irwin Creek (70,10 of 4.9 CFS).
Whole effluent samples were collected on October 27 and October 29 by Wes Bell and facility
representative Jacob Bolick for use in a chronic Ceriodaphnia dubia pass -fail toxicity test. The
test passed. Toxicity test information follows.
Test Type 3-Brood Ceriodaphnia dubia chronic pass -fail
Test Result Pass
Test Concentrations 83%
Control Survival 100%
Control Mean Reproduction 26.2 neonates
Test Treatment Survival 100%
Treatment Mean Reproduction 27.5 neonates
First Sample pH 7.08 SU
First Sample Conductivity 559 micromhos/cm
First Sample Total Residual Chlorine 0.05 mg/L
Second Sample pH 7.31 SU
Second Sample Conductivity 602 micromhos/cm
Second Sample Total Residual Chlorine 0.03 mg/L
Test results for the above samples indicate that the effluent would not be predicted to have
water quality impacts. These samples were split and tested by ETT Environmental, Inc. The
chronic Ceriodaphnia dubia pass/fail test run by ETT resulted in a pass. Please contact us if you
have any questions or if further effluent toxicity monitoring is desired. We may be reached at
[phone].
Basin: Catawba
cc: Wes Bell (MRO)