NCG550751_Resp to Permit Req w/photos_20230327

SwSGStormwater Services Group, LLC
March 22, 2023
Jane Bernard
Raleigh RO — Surface Water Protection
NC Division of Environmental Quality
1628 MSC
Raleigh NC 27699-1628
RE: Gillespie Property, 3815 Brightwood Lu., Durham NC
NPDES General Permit NCG550751
Ms. Bernard:
N'f 72
0
26
Raleigh, North Carolina
Phone: [phone]
Fax: [phone]
In response to Permit requirements, we have collected a discharge sample from the sand filter and have analyzed it for the parameters
indicated in the General Permit. The results are as follows:
Table I — Effluent Analysis Results
Outfall
Date
Flow,
Gals/ Day
(est)
BOD5,
mg1L
TSS,
mg(L
pH,
Std. Units
Ammonia,
mg1L
Total
Nitrogen,
mg(L
Total
Phosphorus,
mg/L
Total
Residual
Chlorine,
mg!
Fecal
coliform,
CFU/ 100
mL
Limits
1000
45.0
45.0
6.0-9.0
Monitor & Report
0.017'
400
Sand Filter
05/11/20
15
< 2.0
153
6.84
Not applicable
> 50.01
1990
Sand Filter
08/10/21
< I
Insignificant Flow Today — not able to collect a sample
Filter
08/22/22
200
29.4
172
5.84
16.5
22.5
3.8
> 5 .03
2.0
—Sand
Sand Filter
03/07/23
1 OV
94.1
46.0
6.94
< 0. 10
16.8
1.2
> 10V
< 1.0
' Receiving stream chlorine levels are not to exceed 17 ligL. Sample is taken at end of effluent pipe. Nearest stream is +/- 1400 ft downgradient.
2 Two adults live in the residence as of March 2023. Flow is based on 50 gpd/ person.
' Residence is on City of Durham water system which is chlorinated. Chlorine tablets are inserted into chlorinator device downstream of sand filter in accordance
with permit.

NC Dept of Envirorunental Quality
NCDEQ
March 22, 2023
Page 2
Theoretical Flow Rate estimate is based on two adults living at
the residence using an industry average of 50 gpd/ adult. Actual
flow rate at this property is much less as typical daily water usage
creates a flow consisting of about two or three milliliters per
minute. There was no flow when this consultant arrived on site.
To collect a sample, the system was surcharged by twining cold
water through the septic system for 30 minutes.
The sand filter effluent pipe discharges into a wooded buffer (see
Figure 1). There is no defined channel from a point about 30 ft
from the end of the pipe into the wooded buffer. The nearest
stream, Unnamed Tributary to Chunky Pipe Creek, is more than
1400 ft from the end of pipe. In the opinion of this consultant,
there is no point source discharge from this septic/ sand filter
system into waters ofthe State.
The original laboratory report and chain -of -custody form is
maintained at the residence.
The next effluent sample will be collected and analyzed in 2 nd or
3rd Quarter 2024. In the meantime, if you have any questions, do
not hesitate to call me.
Sincerely,
STO)"TER SERMcEs Gnoup, LLC
.Lv6es D. Frei
Senior Project Manager
cc: S.Gillespie, Owner
File
MAR 2 7 2023
Raleigh Regional Office
QUALIQ
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Figure I — View looking downgradient from Pipe outlet
Dry channel was dug recently to allow for flow out of pipe.
There is no channel beyond the dug portion; effluent infiltrates into ground
within 15 ft from end of pipe.