NC0004944_Correspondence_20190401

Dewberry Engineers Inc. 919.881.9939
Dewberry2610 Wycliff Road, Suite 410 91
9.881.9923 fax
Raleigh, NC 27607 www.dewberry.com
February 12, 2019
NC Department of Environmental Quality — NPDES Complex Permitting Unit
Attn: Sergei Chernikov, Engineer
Archdale Building
512 N. Salisbury Street
Raleigh, NC 27699
RE: Edge Water Treating, LLC — NPDES Permit NCo004944 - Total Nitrogen Limit
Dear Mr. Chernikov:
On behalf of our client, Edge Water Treating, Dewberry respectfully submits this letter to propose a total
nitrogen limit for the Edge Water Treating wastewater treatment plant located in Salisbury, NC (Salisbury
Facility). The Salisbury Facility discharges wastewater into the High Rock Lake watershed under NPDES
Permit NCo004944 and has recently submitted a NPDES permit modification request to modify the
permit from an Organic Chemical, Plastics and Synthetic Fiber (OCPSF) category 414 to Centralized
Waste Treatment category 437. Based on subsequent conversations with NC DEQ, it is our understanding
that NC DEQ intends to implement an effluent numerical total nitrogen (TN) limit within the modified
permit. NC DEQ indicated that a TN limit is required to freeze TN discharges at 2004 discharge levels
during the interim period prior to finalization of a formal nutrient strategy for High Rock Lake. We
understand High Rock Lake was added to the NC 303d list in 2004 for chlorophyll a and turbidity.
NC DEQ preliminarily suggested an effluent TN limit of 33.5 lb/d. NC DEQ indicated this limit is not
based on historical data from the Salisbury Facility but on the total nitrogen discharge of a similar OCPSF
facility. The similar facility has not been identified. As previously indicated, Edge Water Treating is very
concerned with the proposed limit as its basis is not well defined, and as the limit will have significant
implications on redevelopment of the site and its financial viability. Total nitrogen discharges from
OCPSF facilities can vary significantly depending on specific operations within the facility, the wastewater
treatment infrastructure utilized, and the operational strategy of the wastewater treatment plant. As the
proposed limit is not based on historical data from the Salisbury Facility, it is not representative of the
2004 discharges from the Salisbury facility and could be overly restrictive and inconsistent with the intent
to freeze discharges at 2004 levels.
At the time of our January 23, 2019 meeting with NC DEQ, historical total nitrogen data from the
Salisbury Facility had not been identified. NC DEQ indicated that in the absence of site specific historical
data, NC DEQ would consider an alternate proposed limit to be based on effluent data from multiple other
OCPSF facilities, estimation/modeling of 2004 total nitrogen discharges from the Salisbury Facility, or a
combination of both.
To develop a proposed total nitrogen limit, Dewberry reviewed the following:
• Historical NCo004944 files retrieved from NC DEQ Central File archives
• Discharge data from four other OCPSF polyester fiber dischargers.
The files retrieved from archive contained limited historical total nitrogen data for the Salisbury Facility
which included the following:
• August 1992 — July 1992: Once per month sample analyzed for total nitrogen
• January 2009 — December 2009: Once per month sample analyzed for total nitrogen
Page 1 of 3

Copies of the files referenced above are provided in Attachment A. The 2009 samples were collected
immediately after the Salisbury Facility was sold from Invista to Performance Fibers; it is our
understanding that by 2009 Performance Fibers had significantly reduced staff and production
operations at the Salisbury Facility. As such, the 2009 data is not representative of 2004 discharge
conditions and is not used for this evaluation. The 1992/1993 data represents a time when the Salisbury
Facility was operating at full production capacity and is deemed the most representative to use in the
evaluation to estimate 2004 discharges.
An anaerobic treatment system (Celrobic®) for contaminated groundwater was operated at the Salisbury
Facility from approximately 1994 — 2004. The effluent from the Celrobic® system was discharged to the
Salisbury Facility's wastewater treatment plant (WWTP). The Operation Manual for this system was
obtained from the Salisbury Facility control room and excerpts are provided in Attachment B. The
Operation Manual indicated the system included an ammonia addition system to provide nutrients for the
anaerobic organisms. The Operation Manual instructed that ammonia be dosed to achieve an excess of
30 mg/l in the anaerobic system effluent which was designed to operate at l00,80o gallons per day. The
Operation Manual also indicated that biomass was wasted from the Celrobic® system to the WWTP.
Therefore the Celrobic® effluent would be expected to contain two primary forms of total nitrogen:
excess ammonia at 30 mg/l and insoluble organic nitrogen from the wasted biomass.
As the Celrobic® system was not operational until 1994, the 1992/1993 data presented above would not
capture the total nitrogen discharges from the Celrobic® system. The Celrobic® system was operated
until 2004 and thus it is assumed to have been operated during the period the impairment was identified
in High Rock Lake. As such, it is valid to include nitrogen contributed from this system in this evaluation
if the intent is to freeze nitrogen dischargers at the time the impairment was identified. In addition, the
Consent Order (date October 4, 2000) is still active and the Celrobic® system may be operated again in
the future if groundwater monitoring indicates additional remediation is required. Excerpts from the 2017
Annual Groundwater Report by CAN Holdings LLC are provided in Attachment D.
To estimate the total nitrogen effluent discharges attributable from the Celrobic® system, Dewberry
assumed the residual effluent ammonia would pass through the WWTP and the nitrogen present in the
waste sludge would be hydrolyzed in the WWTP and both would be discharged in the WWTP effluent. The
additional chemical oxygen demand load from the anaerobic effluent would result in additional sludge
generation at the WWTP and a portion of the nitrogen would be used by the WWTP to support that cell
growth. The calculations presented in Attachment B include an estimate of the sludge generated as a
result of the anaerobic system and subtracts the nitrogen that would report to that biomass. The model
calculations and supporting documentation are presented in Attachment B. The net total nitrogen impact
from operation of the Celrobic® system is calculated to be 117 lb/d total nitrogen.
To estimate non-Celrobic® effluent total nitrogen discharges, the 1992/1993 data was utilized. The
average and maximum effluent total nitrogen from the 1992/1993 data was calculated to be 3.3 mg/l and
4.7 mg/l, respectively. As the peaking factor of 1.4 is relatively low and 50% of the data is above the
average, we propose to use the maximum value of 4.7 mg/l as representative of historical total nitrogen
discharges prior to operation of the Celrobic® anaerobic system. A concentration of 4.7 mg/l at the
permitted flow rate of 2.305 MGD is an equivalent mass discharge of 90.4 lb/d.
The sum of the 90.4 lb/d of historical total nitrogen and the 117 lb/d total nitrogen contributed by the
Celrobic® system result in an estimated 2004 effluent total nitrogen load of 207.4 lb/d. Therefore, we
propose a numerical total nitrogen permit limit of 207.4 lb/d. We propose once weekly
monitoring with an annual average limit, which is consistent with your email on December 14, 2018. The
proposed 207.4 lb/d total nitrogen limit for the Salisbury Facility is the equivalent of 10.7 mg/1 total
nitrogen at the maximum permitted flow rate of 2.305 MGD.
Dewberry
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To support this evaluation, Dewberry researched the effluent total nitrogen discharge from similar OCPSF
facilities in order to evaluate if the proposed limit of 207.4 lb/d is reasonable for discharges from a
polyester fiber manufacturer. Our search focused on polyester fiber manufacturers with current or
historical direct discharge permits. Table 1 below summarizes the data obtained for four manufacturers in
NC. Excerpts from the supporting documentation is provided in Attachment C. This information was
obtained from NC DEQ's Laserfiche Document Management System but full copies can be provided upon
request.
DuraFibers
NC0001899 Manufacturer of polyester
2016 NPDES Permit
>6.9 mg/I*
(Moncure, INC)
resin and fibers
Renewal Application
(*only ammonia data
was available)
DAK Americas
NC0003719 Manufacturer of polyester
2016 NPDES Permit
8.9 — 27.4 mg/I
(Fayetteville, INC)
chip
Renewal Application
Celanese
NC0004952 Manufacturer of polyester
2018 NPDES Permit
0.62 mg/I
(Shelby, INC)
resins
Renewal Application
Invista
NC0001112 Manufacturer of polyester
2014 NPDES Permit
39.5 mg/I
(Wilmington, INC)
polyols
Renewal Application
The effluent total nitrogen data from other polyester manufacturers ranges from o.62 — 39.5 mg/l. The
wide range is likely due to difference in production operations and/or wastewater treatment operations at
the facilities. For example, the finishing chemistries for polyester varies by manufacturer. Finish
chemistries, including those used at the Salisbury Facility, use urea as a carrier during the finishing
process. The average effluent flow rate from September 1992 - August 1993 at the Salisbury Facility was
1.029 MGD (Attachment A). At this flow rate, the 207.4 lb/d translates to 24.1 mg/L. This concentration is
within the range of effluent TN concentrations observed at similar OCPSF facilities. Flow data from 1992-
1993 is used for this comparison as this time period is the closest to 2004 for which data was obtained
from NCDEQ electronic and archived files and was during a period when the facility was operating at a
production capacity similar to 2004. Diane Rodman with Central Files indicated that some historical
discharge monitoring reports including records from 2004 have been destroyed.
We appreciate your consideration. Please feel free to contact me at 919-424-3764 with any questions
regarding this matter.
Sincerely,
41e Dud -
Leigh -Ann Dudley, PE
Project Manager
Cc: Julie Grzyb, NC DEQ
MariJon Owens, Edge Water Treating
Greg Coleman, Edge Water Treating
Ryan Ford, PE, Edge Water Treating
Tom McKittrick, Edge Water Treating
Katie Jones, PE, Dewberry
Dewberry,
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