NC0089702_NOV-2019-LM-0056 Response_20190731

Mid Atlantic
ie4rr.ring R Environmental Solutlont
July 31, 2019
North Carolina Department of Environmental Quality
Division of Water Resources
Raleigh Regional Office
Attention: Rick Bolich, LG, Assistant Supervisor
3800 Barrett Drive
Raleigh, North Carolina 27609
409 Rogers View Court
Raleigh, NC 27610
*Hitt: 919 I50.9918
latslmlle 919 250.99S0
MAAONLINE COM
NC Dept of Environmental Quality
- 5 2019
Ralcigh Regional Office
Subject: RESPONSE TO NOTICE OF VIOLATION
SOLIS BRIGHTLEAF APARTMENTS - BROWNFIELD
1001 WEST MAIN STREET
DURHAM, DURHAM COUNTY, NORTH CAROLINA
NPDES PERMIT NO. NCO089702
TRACKING NUMBER NOV-2019-LM-0056
Dear Mr. Bolich:
On behalf of Solis Brightleaf Apartments LLC, Mid -Atlantic Associates, Inc. submits this
letter in response to a Notice of Violation (NOV-2019-LM-0040) dated July 24, 2019. In
the NOV two conditions were identified by DEQ during review of the April 2019 Discharge
Monitoring Report (DMR). The conditions and our response to address these conditions
are as follows:
Condition: The daily maximum and monthly average limit discharge of 1,500 gallons per
day as prescribed by the NPDES permit were exceeded.
Response: The water being discharged under this permit originates from groundwater
located beneath a partially subterranean parking deck which underlies an apartment
building. Groundwater in this part of Durham is shallow and dewatering beneath the
parking deck is required to maintain dry conditions in the parking structure. Due to the
presence of chlorinated solvents in the groundwater at the site, treatment of the
groundwater is required prior to discharge. At the time of the NPDES permit application,
flow from the dewatering drain network could only be estimated based on soil types and
water table elevation data. These estimates predicted average flows of less than 800
gallons per day. The permit application requested, and was granted, 1,500 gallons per
day to provide a cushion in the event the estimations were low.
In February 2019 the dewatering/treatment system went into operation with discharge
under the NPDES permit (it had been discharging temporarily to the City of Durham
POTW prior to this time). From February thru May 2019 flow measurements were
recorded on an approximate weekly using the average daily flow rate between readings.
NCDEQ advised that the permit requires daily readings and these were initiated in late
EXPERIENCED CUSTOMER FOCUSED INNOVATIVE —

Response to NOV July 31, 2019
Solis Brightleaf Apartments- Brownfield Page 2
Durham, North Carolina
May as indicated below. The data collected over this time indicated that average daily
flows were frequently exceeding the limit established in the permit. The period leading up
to February 2019 and up through approximately April 2019 have been exceptionally wet.
We had anticipated that the flow rates would subside and they have to a certain degree,
but the daily maximum flow rate is frequently exceeded. Unfortunately we have no control
over the rate at which the system operates since it is driven by weather. However, the
system has the hydraulic capacity and the effluent analytical data show it has the
treatment capacity to handle the increased flow rates. To address the increased
discharge rate, we have submitted a NPDES Permit Modification Request dated
June 28, 2019 to Joe Corporon in the DEQ Water Quality Permitting Section to
increase the maximum allowable discharge from 1,500 to 6,500 gallons per day. To
date we have not received a determination from the Permitting Section on our request.
Condition: The flow meter readings for the effluent discharge in April 2019 were
recorded on a weekly basis concurrently with effluent sample collection. The flow meter
continuously records the effluent but the flow meter reading was only recorded during site
visits. We were informed in May 2019 by Cheng Zhang of DEQ that continuous recording
equates to daily recording of the flow meter reading.
Response: Per our written response to the May 22, 2019 NOV, dated May 31, 2019,
the maintenance staff at the apartment building has been trained to record daily flow
meter readings. Daily readings have been occurring since the end of May 2019, but
please be advised that this change will not appear on the DMRs until the June 2019 report
is submitted.
If you have any comments or questions on our response to these conditions, please
contact me at 919-250-9918. We recognize the importance of permit compliance and we
have taken actions to address the deficiencies.
Sincerely,
MID -ATLANTIC ASSOCIATES, INC.
i,f
Daniel H. Nielsen, P.E.
Principal Engineer
Cc: Brandon Yancey, Solis Brightleaf Apartments, LLC
Mid Atlantic