NC0087963_More Information (Received)_20220502

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April 29, 2022 ^Ec
Ms. Min Xiao, PE ('C �' " ��
Environmental Engineer MAY 0 2 2022
NPDES Industrial Permitting NG�NC DEQ / Division of Water Resources /Water Quality Permitting EQ/D
1617 Mail Service Center WR/NPDES
Raleigh, North Carolina 27699-1617
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RE: Additional Information Request for Buckeye Creek WWTP, NC0089763
The Bluffs at Blowing Rock Property Owner's Association, Inc.
Boone, NC 28607
Dear Ms. Xiao:
We are in receipt of your review comments for the subject project that were emailed on
April 1, 2022. On behalf of the Owner, we hereby offer this letter and its enclosures as
our responses to your comments. Below you'll find a comment-response format list for
each comment offered in your review.
1. After Equalization, the hourly peaking factor is 2. Please explain how this hourly
peaking factor is determined.
Response: The sewer collection system conveying the wastewater to the
WWTP is a new gravity sewer system. The on-line flow equalization basin is
designed to equalize the dry-weather flow.
The EQ pumps are rated at 70 gpm limiting the maximum day flow of
100,000 gpd to downstream process units to two times of the influent
design flow of 50,000 gpd.
The package treatment plant is designed in such a way that all peak hourly
flow rates will be handled by the flow equalization system. In the flow
proportioning box of the flow equalization system, there are two v-notch
weirs. Each weir allows the average design flow of 50,000 gpd to flow into
the respective secondary treatment system trains. Any excess flow(peak
hourly flow rates) shall gravity flow from the flow proportioning box back
into the flow equalization chamber for processing. Therefore, the
secondary treatment systems will never see a flow larger than design flow
rate of 50,000 gpd per train.
MCGILL ASSOCIATES 55 BROAD STREET, ASHEVILLE, NC 28801/828.252.0575/MCGILLASSOCIATES.COM

Ms. Min Xiao, PE
April 29, 2022
Page 2 of 3
2. There is only one manual bar screen for the facility. Please justify if the manual
bar screen is down for maintenance or repair, can debris still be sufficiently
screened prior to entering EQ basin?
Response: A standby manual bar screen is provided. if the on-duty bar
screen is down for maintenance or repair, the standby unit can be easily
put into operation.
3. It was indicated in the ATC application form that the facility is within the 100-year
flood plain. How many feet is the site raised above the BFE? The 100-year flood
elevation shall be specified in the site plan and profile views (including the
hydraulic profile).
Response: This is an error. The facility is not within the 100-year flood plan.
The page of the ATC form is corrected and attached.
4. The Hydraulic Profile shall include the water surface elevations within each
treatment unit for two flow conditions: (1) the NPDES permitted flow with all trains
in service and (2) the peak hourly flow with one treatment train removed from
service. I have included two examples below from other projects as reference
hydraulic profiles:
Response: As explained in the Response to Comment 1, the system is
designed so that only 50,000 gpd will ever be allowed into each train of the
system. The EQ pumps are controlled via float switch operation, so they
will continue to pump at their design capacity. The flow proportion box will
only allow 50,000 gpd to go into either train, so any peak hourly flow will be
returned to the EQ chamber.
Also the water level will remain unchanged even if there is only 25,000 GPD
in each train. Basically, if this happens the detention time in each aeration
chamber would be 48 hours instead of the 24 hours as designed. The EQ
pumps would remain at their rated capacity pump rate but would pump less
often due to the lower flow rate.
Therefore, the hydraulic profile provided is for both flow conditions: (1)
both trains in service at the design flow of 50,000 gpd; (2) one train in
service with the peak flow of 100,000 gpd.
Please see the revised G-003 for clarification.

Ms. Min Xiao, PE
April 29, 2022
Page 3 of 3
One (1) hard copy of all revised documents has been enclosed. We trust that this revised
submittal will address all remaining items for approval of the plans and specifications. If
you have any further questions, please contact me at [phone].
Sincerely,
MCGILL ASSOCIATES, P.A.
C 'c2""
MJ CHEN, PE, PhD
Senior Project Manager
Enclosures:
Revised page 8 of ATC-12-14
Revised G-003
cc: Jay Harrill —The Owner (via email)
J. Meliski, PE — McGill Associates, PA. (via email)
Matthew Oetting, — McGill Associates, PA. (via email)

State of North Carolina
,.; Department of Environmental Quality
Division of Water Resources
Water Resources
ENVIRONMENTAL QUALITY APPLICATION FOR AUTHORIZATION TO CONSTRUCT PERMIT(FORM ATC-12-14)
4. Per 15A NCAC 02T.0505(i), by-pass and overflow lines are prohibited. Is this condition met by the design?®Yes or❑No
If no,describe the treatment units bypassed,why this is necessary,and where the bypass discharges:
5. Per 15A NCAC 027.0505(k), multiple pumps shall be provided wherever pumps are used. Is this condition met by the
design?®Yes or❑ No. If no,provide an explanation:
6. Per 15A NCAC 02T.0505(1), power reliability shall be provided consisting of automatically activated standby power supply
onsite capable of powering all essential treatment units under design conditions,or dual power supply shall be provided
per 15A NCAC 02H.0124(2)(a). Is this condition met by the design? ®Yes or❑ No. If no, provide(as an attachment
to this Application)written approval from the Director that the facility:
➢ Has a private water supply that automatically shuts off during power failures and does not contain elevated water
storage tanks,and
➢ Has sufficient storage capacity that no potential for overflow exists,and
➢ Can tolerate septic wastewater due to prolonged detention.
7. Per 15A NCAC 02T.0505(o),a minimum of 30 days of residual storage shall be provided. Is this condition met by the
design? ®Yes or❑ No. If no,explain the alternative design criteria proposed for this project in accordance 15A NCAC
02T.105(n):
8. Per 15A NCAC 02T.0505(q),the public shall be prohibited from access to the wastewater treatment facilities. Explain how
the design complies with this requirement:6'chain-link fence topped with 3 strands of barbed wire.
9. Is the treatment facility located within the 100-year flood plain? ❑Yes or® No. If yes,describe how the facility is
protected from the 100-year flood:
C. WASTEWATER TREATMENT UNIT AND MECHANICAL EQUIPMENT INFORMATION—COMPLETE FOR NEW OR
EXPANDING FACILITIES AND FOR MODIFIED TREATMENT UNITS
1. PRELIMINARY AND PRIMARY TREATMENT(i.e., physical removal operations and flow equalization):
No.of Plan Sheet Specification Calculations
Treatment Unit Type Size per Unit Provided?
Units Reference Reference (Yes or No)
Manual Bar Screen 1 MGD at peak hourly flow M-101 460753
Mechanical Bar MGD at peak hourly flow
Screen
Grit Removal MGD at peak hourly flow
Flow Equalization 1 -- 12,500 gallons M-101 460753
Primary Clarifier Circular ft diameter; ft side
water depth
Primary Clarifier Rectangular square feet; ft side
water depth
Other
Application for Authorization to Construct Permit(FORM ATC-12-14) Page 8