NC0024325_Staff Report_20160203

NPDES DOCUMENT SCANNING COVER SHEET
NC0024325
North Buffalo Creek WWTP
NPDES Permit:
Document Type:
Permit Issuance
Wasteload Allocation
Authorization to Construct (AtC)
Permit Modification
Complete File - Historical
Engineering Alternatives (EAA)
Correspondence
Owner Name Change
Let.)
Staff
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
February 3, 2016
This document is printed on reuse paper - ignore any
content on the reverse side

State of North Carolina
Division of Water Resources
Water Quality Regional Operations Section
Environmental Staff Report
Quality
February 3, 2016
To: Julie Grzyb
NPDES Unit
From: Mike Mickey
Winston-Salem Regional Office
Subject: Staff Report
Greensboro's North Buffalo POTW
NPDES Permit No. NC0024325
Guilford County
I. GENERAL AND SITE VISIT INFORMATION
1. Was a site visit conducted? No.
RECEIVED/NCDEQ/DWR
FEB 1 1 2016
Water Quality
Permitting Section
a. Inspection report attached? No. The last inspection was conducted 4/23/15.
b. Facility contact: Ed Osborne, ORC Phone: [phone].
e. Driving directions: Take Hwy 29/70 North off I-40Bus85 and then exit onto Wendover Avenue East.
Proceed on Wendover to the Huffine Mill Road intersection and turn left. Proceed on Huffine Mill
Road to Nealtown Road and turn left. At the end of Nealtown Road turn left onto White Street. The
entrance to the North Buffalo POTW if 0.5 mile on the right.
2. Discharge Point(s): Latitude: 36° 06' 34" Longitude: 79° 44' 53"
(note: these coordiantes for the outfall are from Google Earth).
3. Receiving stream or affected surface waters:
Classification: North Buffalo Creek
River Basin and Subbasin No. Cape Fear, 03-06-02
Describe receiving stream features and pertinent downstream uses: The nearest water supply intake
is the Town of Pittsboro's, approximately 65 river miles downstream. The flow path to the intake is
from North Buffalo Creek to Buffalo Creek to Reedy Fork to Haw River to Jordan Lake. At the
discharge point, the in -stream waste concentration is 96.5% at 7Q10 conditions.
II. PROPOSED FACILITIES: NEW APPLICATIONS NA.
III.EXISTING FACILITIES: MODIFICATION AND RENEWAL APPLICATIONS
1. Are there appropriately certified Operators in Charge (ORCs) for the facility? Yes.
ORC: Ed Osborne Certificate #: 9898 Backup ORC's: Multiple
FORM: WQROSSR 04-14 Page 1 of 3

2. Are the design, maintenance and operation of the treatment facilities adequate for the type of waste and
disposal system? Yes.
Description of existing facilities:
The 16.0 MGD permitted facility consists of the following:
* three mechanical bar screens
* aerated grit removal
* influent pump station (two 12.5 MGD pumps to convey to N. Buffalo)
* four primary settling tanks
* four aeration basins
* five secondary clarifiers
* four traveling bridge tertiary sand filters
* liquid disinfection with sodium hypochlorite
* two contact chambers with reaeration
* flow measurement
* liquid dechlorination with sodium bisulfite
* standby power (Duke Power owned generator).
Solids generated at the North Bufallo POTW are stored in a single gravity thickener/holding tank
prior to pumping to the T.Z. Osborne POTW influent via a 54-inch line. Ultimate disposal is by
incineration.
Current permitted flow: 16.0 MGD. The average daily flow for 2014 — 2015 was approx 6.8 MGD.
3. Is the description of the facilities as written in the existing permit correct? Yes.
Are there any compliance/enforcement issues that should be resolved before issuing this permit? No.
The North Buffalo facility was compliant with all permit effluent limits in 2014 and 2015.
4. Possible toxic impacts to surface waters: None known. Facility passed all toxicity tests in 2014 & 2015.
The permit requires quarterly toxicity testing at an effluent concentration of 90%.
5. Pretreatment Program (POTWs only): The City of Greensboro operates a pretreatment program for the
North Buffalo and the TZ Osborne POTW's.
IV. ADDITIONAL REGIONAL STAFF REVIEW ITEMS
Just FYI -
• Due to the age of the North Buffalo facility, the City of Greensboro has chosen to expand the TZ
Osborne POTW for biological nutrient removal and close down the North Buffalo POTW.
• The decommissioning of the North Buffalo POTW could possibly occur in 2017. In preparation,
the Division issued wastewater collection permit No. WQ0036639 on 8/7/13 for the construction of
the necessary components to transfer all of the North Buffalo flow to the TZ Osborne POTW for
final treatment.
FORM: WQROSSR 04-14 Page 2 of 3

• The NPDES permit was modified June 1, 2013 to reduce the monitoring frequency for BOD, TSS,
NH3-N and fecal coliform from daily to 2/week per DWR's guidance for "Reduction of Monitoring
Frequencies for Exceptionally Performing Facilities". The facility enjoys the distinction but has
continues to monitor daily anyway.
• The North Buffalo facility typically treats and discharges 6.0 to 8.0 MGD. The remainder of the
influent is sent through the transfer pumping station to the TZ Osborne facility for treatment.
V. REGIONAL OFFICE RECOMMENDATIONS
1. Do you foresee any problems with issuance/renewal of this permit? No.
2. Recommendation: Issue.
Signature of report preparer & Date:
Signature of Regional Supervisor & Date:
(1141, TT,A4
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FORM: WQROSSR 04-14 Page 3 of 3

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