NC0081621_More Information (Received)_20190719

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Governor • /y
MICHAEL S.REGAN
Secretary
LINDA CULPEPPER NORTH CAROLINA
Director Environmental Quality
July 19, 2019
Mr. Charles A. Willis, P.E.
Willis Engineers
10700 Sikes Place
Charlotte,NC 28277
Subject: Request for additional information
NPDES Application NC0081621
Muddy Creek WWTP
Dear Mr. Willis:
The Division has reviewed your submitted additional information to justify the requested 1.0 MGD
expansion dated March 15,2019.Your 20-year projected population for Town of Midland is based
on the assumption that the population growth is equal within the Cabarrus County. However, this
is not the case in the Town of Midland. Based on your submitted projected population for Town
of Midland dated July 2018, which is based on NC census, the population growth in the Town is
seeing a much lower growth rate. Per the NPDES's Engineering Alternative Analysis (EAA)
Guidance document, the projected flow must be calculated based on the projected population to
be served within the service area. Since Muddy Creek WWTP is serving only Town of Midland;
therefore,the Division only concurs with the projected flow of 0.53 MGD based on the population
growth of Town of Midland and not the County.
In regards to your request to reconsider the effluent limitations for BOD5 and NH3 for the 0.53
MGD and 1 MGD expansion as stated in the 2007 speculative limit, the Division received an
updated QUAL2K model from Charlotte Water's Mallard Creek WWTP prepared by Brown and
Caldwell. The model simulates the Rocky River within the Yadkin River Basin and includes the
subject facility. The Division will run the model to determine if new limits can be given to your
facility. However, the Division believes that the limits will stay the same as in 2007 speculative
limit.
To enable us to complete our review in accordance with N.C.G.S. 143-215.1 and 15A NCAC
2H.0105,please provide additional or revised information to address the following comments:
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North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street I I617Mail Service Center I Raleigh,North Carolina 2 76 9 9-1617
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1. The additional information you submitted indicated that Muddy Creek WWTP has received
requests from developers for over 343,000 gallon per day (gpd) of additional flow which
are currently under review. Please provide documentation showing such requests.
2. The information you submitted mentioned that the facility has an existing commitment of
70,000 gpd in addition to existing WWTP flow rate. Please provide more
details/explanation about the 70,000 gpd existing commitment.
If no response is received by September 20, 2019 [per 15A NCAC 2H.0107(b)], the Division will
go ahead and issue a permit modification for 0.53 MGD. If you have any questions,please contact
me at 919-707-3607 or email at [e-mail].
Sincerely,
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Qais Banihani, Environmental Engineer
NPDES Complex Unit
Division of Water Resources/NCDENR
cc: Mr. John W. Ritchie,Wastewater Operations Manager, WSACC
Mr. Timothy R. Kiser, P.E., Engineering Director, WSACC
Mr. T. Mark Fowler, Facilities Director, WSACC
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