NC0044423_Corrective Action Plan_20190329

March 29, 2019
Joe R. Corporon, L.G Appalachiwan
Water Quality Permitting Section - NPDES STATE E UNIVERSITY
Division of Water Resources, NCDEQ Physical Plant
512 Raleigh, NC 27604 N Salisbury Street ASU Box 32105
RECEIVEDIDEENPU®WR Boone, NC 28608-2105
Raleigh,
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Re: Corrective Action Plan
NPDES Permit No. NCO044423 Water Resources
Appalachian State University WTP Permitting Section
Dear Mr. Corporon,
Per Condition A(3) of NPDES Permit No. NC0044423, Appalachian State University (ASU) Water Treatment Plant (WTP) is
required to submit a Corrective Action Plan (CAP) annually "summarizing actions to be taken to achieve compliance with
Total Copper, Total Zinc, and Turbidity at Outfall 001." Enclosed herein is the Corrective Action Plan and the proposed
schedule for implementation.
Total Copper and Total Zinc
NCO044423 includes the following numerical effluent limits for total copper and total zinc, which become effective
January 1, 2021:
Monthly Average, ug/I Daily Maximum, ug/I
Total Copper, 4 5.2
Total Zinc 63 63
Monthly effluent monitoring conducted in accordance with the requirements of this permit indicate the effluent
concentrations exceed the numerical limits regularly. Total copper monthly monitoring results vary widely and have
exceeded the daily maximum and/or monthly average limits every month but December 2018. Total zinc monthly
monitoring results also fluctuate wildly and have exceeded the daily maximum and monthly average limit often.
Monitoring of the raw water also shows fluctuations that exceed the daily maximum for Copper. At least one of these
test results was a week after a significant rain event. We have experienced numerous anomalous rain events for the
past 2 years.
Another area of investigation and upgrade is the operation of the backwash process for our filter modules. It is evident
that the backwash cycles have not been as effective as needed resulting in more frequent backwash cycles and possible
release of residue build up intermittently. If residue is released in larger quantities intermittently, it could explain the
variation in test results.
ASU recently replaced all the actuated valves on one filter module. The improved operation released higher than
average residue in the initial backwash cycles. ASU plans to replace the actuated valves on the remaining three filter
modules in late May or early June.
In addition to the valve replacements, we are pursuing different maintenance wash cycles and cleaning solutions with
the filter manufacturer. We hope to implement these improvements by this summer as we continue to evaluate
whether treatment process changes are required to meet the metals requirements.
A MEMBER INSTITUTION OF THE UNIVERSITY OF NORTH CAROLINA AN EQUAL OPPORTUNITY EMPLOYER

Turbidity
NC0044423 includes a numerical effluent limit for turbidity not to exceed 10 Nephelometric Turbidity Units (NTU).
Effluent monitoring data collected in accordance with the permit indicates the effluent turbidity at times exceeds the
numerical limit. We understand the effluent numerical limit was established to be protective of water quality. The
effluent numerical limit was established to be equivalent to the instream water quality standard of 10 NTU for Trout
waters. We also understand the NC DEQ Changes to Water Treatment Plant Strategy (October 2009) states that
"turbidity will not be limited except for facilities that discharge to a receiving stream which is impaired for turbidity".
Norris Branch Reservoir is not included in the 303d Impaired Water Bodies List and historical and recent data collected
within Norris Branch Reservoir indicate the water quality within the reservoir is below the 10 NTU stream standard for
Trout waters. Based on this recent data, it appears the ASU WTP discharge is not increasing the instream turbidity
above natural background conditions or the instream water quality standard.
Dissolved Oxygen
Dissolved oxygen (DO) is not a parameter required to be addressed by the CAP; however, recent effluent dissolved
oxygen noncompliance events warrant evaluation of this parameter. We understand the effluent numerical limit was
established to protect water quality. The effluent numerical limit was established to be equivalent to the instream
minimum of 6 mg/I for Trout waters. In February 2018, ASU collected dissolved oxygen data at multiple locations within
Norris Branch Reservoir, upstream and downstream of the ASU discharge. The data indicates the dissolved oxygen
concentrations within the reservoir are above the 6 mg/I minimum stream standard and the ASU WTP discharge is not
decreasing the instream DO below the instream minimum of 6 mg/I.
The noncompliance events occurred with DO sampling within the wastewater containment facility and did not reflect
the DO at the discharge point. Entrained air within the discharge pipe is significantly aerating the effluent and all
samples taken at the discharge point have well exceeded the minimum required level of dissolved oxygen.
Actions
ASU will continue with monitoring of source water to compile the data to allow an informed and reasonable judgment
for the permit renewal. The goal will be to protect and maintain the source water as a high quality water while
maintaining an affordable water source for ASU.
ASU will implement the upgrades to the filter modules, weekly maintenance wash programs and monthly Clean In Place
(CIP) procedures and monitor the changes. The goal will be to increase the efficiency of the backwash and cleaning
procedures without increasing waste water discharge amounts.
ASU will begin the permit renewal process in the spring of 2020. This should allow enough time for the Water Quality
Permitting Section and the Regional Office to evaluate the relevant data and implement any required process changes.
Should you have any comments or questions or require additional information, please feel free to contact me at
828.262.8787.
Sincerely,
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WIF
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Patrick S. Brittain, PE
License No. 022085
Asst. Director Facilities Operation and Maintenance
Cc. Sherri Knight, PE, Environmental Regional Supervisor, NCDEQ
Mike Mickey, Environmental Program Consultant, NCDEQ