NC0003719_Report_20091230

NPDES DOCIMENT SCANNIN`: COVER SHEET
NC0003719
Cedar Creek site 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
Report
Instream Assessment (67b)
Speculative Limits
Environmental Assessment (EA)
Document Date:
December 30, 2009
This document is printed on reuse paper - ignore any
content on the reYerse aide

DAK Americas
FIBERS, MONOMERS & RESINS
December 30, 2009
Mr. Joe Corporon
Division of Water Quality
NC Department of Environment and Natural Resources
1617 Mail Service Center
Raleigh NC 27699-1617
Subject: DAK Americas LLC — Cedar Creek Site
NPDES Permit No.: NC0003719
Dear Mr. Corporon:
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September 4, 2009 the DAK Americas LLC Cedar Creek site's NPDES permit was issued with
Section A.(5.) Plastics Recycling Facility (PRF) — Waste Characterization requesting a written
report, anticipating the character of PFR wastes generated under SIC 5162, and specifically
identifying:
1. waste chemical character and methods used to identify, quantify, and characterize wastes,
2. waste treatability by existing onsite WWTP processes
3. examples of character of wastestreams from similar active/operating SIC 5162 PRFs
4. any anticipated interference by PRF wastes with existing wastestream treatability
5. any new treatment units identified or processes requiring ATC.
Enclosed please find the Biological System Assessment Report which describes the character of
wastewater from Clear Path Recycling LLC, the plastics recycling facility under construction
adjacent to the DAK Americas facility in Fayetteville, North Carolina. Items 1,2, 4, and 5 are
included in this report. No new treatment units or processes requiring ATC are required at
DAK's WWTP to treat the process wastes from the Clear Path Recyc mg cilityl e
an icipa e start up date is April 1, 2010. -
As for Item No. 3 above, no examples of similar active/operating PRFs discharging directly to
surface waters have been identified.
If you have any questions, please call me at [phone] in my office or at [phone] on
my cell phone.
Sincerely,
Elizabeth Wike
Environmental Engineer
www.dakamericas.com
RECEIVED
JAN
2010
DENR - WATER QUALITY
POINT SOURCE BRANCH
DAK Americas LLC
3500 Daniels Road, N.E. • Leland, NC 24,451
I -877-432-2766

Permit NC0003719
A. (3.) BIOCIDE APPROVAL
The Permittee shall obtain approval from the Division's Aquatic Toxicology Unit prior to discharging any
biocide (not previously approved by the Division) under this permit. Approval for use of any biocide not
previously The Permittee shall request approval of any new unauthorized biocide at least 90 days in advance of
planned usage.
Contact the Aquatic Toxicology Unit for detailed instructions on requesting biocide approval:
NC DENR / DWQ / Aquatic Toxicology Unit
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Concentrations of chromium, copper, or zinc added to biocides shall not exceed applicable water quality
standards or action levels in the receiving stream.
A. (4.) LABORATORY TEST -METHOD QUANTITATI .pl-.IJEVELS AND:COMPLIANCE
For any given parameter, the Permittee must apply a state certified:ana1ytica1 tesimethod with.:a practical
quantitation level (PQL) at or below the NPDES permit limit. If such,,leyel ckf analytical sensitivity is not
technologically feasible, the Permittee shall employ. a state-cektifed)analytical4nethod yvith the lowest available
test -method PQL, and values reported as nQt detected by this"lowest availa ile -PQL shall be deemed
"compliant" with this permit.
! .
(------
A. (5.) PLASTICS REC,YCLING,FACILITY (PRF) - WASTE CHARACTERIZATION
Although PRF..constiruction.does not require -a -IDES Authorization to Construct (ATC) Pe it, an
ATC permit is`recLuired-tor`any additional reatment units or processes necessary to treat PRF astes.
* ,N. )
d
Therefore, during construct o f the proposed PRF (flow estimated at 0.111 MGD), DAK sh 1 locate
and designate internal PRF Outfat6,01, a sampling location influent to the onsite WWTP, w ereby the
Permittee may sample and: -analyze PRF wastes prior to mixing with other wastes. No later th 90 days
prior to receiving PRF wastes at'the onsite WWTP, DAK shall provide a written report antici ating the
character of PRF wastes generated under SIC 5162 to include:
1. waste chemical character and methods used to identify, quantify and characterize
2. waste treatability by existing onsite WWTP processes
3. examples and character of wastestreams from similar active/operating SIC 5162 P
4. any anticipated interferenceRF wastes with existing wastestream treatability
5. any new treatment units identified or processes requiring ATC
The Division reserves the right to reopen this permit to include additional treatment and/or m
based on a satisfactory waste characterization.
astes
nitoring

BIOLOGICAL SYSTEM ASSESSMENT REPORT
DAK AMERICAS, LLC
3216 CEDAR CREEK ROAD
FAYETTEVILLE, NORTH CAROLINA 28312
EnSafe Project Number
0888806412
Prepared for:
DAK Americas, LLC
3216 Cedar Creek Road
Fayetteville, North Carolina 28312
Prepared by:
EnSafe Services, P.C.
5724 Summer Trees Drive
Memphis, Tennessee 38134
[phone]
[phone]
www.ensafe.com
N.C. Firm License No. C-1440
November 2009

Site Name:
Site Location:
Biological System Assessment Report
DAK Americas, LLC
3216 Cedar Creek Road
Fayetteville, North Carolina 28312
Site Contact Information:
Ms. Elizabeth Wike
DAK Americas, LLC
3216 Cedar Creek Road
Fayetteville, North Carolina 28312
Engineer Contact Information:
Mr. David Hutson, P.E
EnSafe Inc.
220 Athens Way, Suite 410
Nashville, Tennessee 37228
[phone]
[e-mail]
Seal and Signature of Certifying PE
'/ ,
0
• a •

EJVSAFE
Biological System Assessment Report
DAK Americas, LLC
Fayetteville, North Carolina
November 2009
1.0 INTRODUCTION
1.1 General
EnSafe Inc. has prepared this biological treatment assessment report based on information
provided by DAK Americas, LLC, (DAK) and Clear Path Recycling, LLC (CPR).
CPR is proposing to construct a polyethylene terephthalate (PET) recycling plant at the existing
Cedar Creek site. Currently, DAK and DuPont Teijin Films (DuPont) operate production facilities at
this site. Monsanto formerly operated a Roundup production facility that ceased operations
in 2002/2003.
The existing industrial wastewater treatment plant (IWTP) currently receives and treats DAK and
DuPont process wastewater, sanitary wastewater, and some storm water. Non -contact
cooling water and other existing facility storm water bypass this treatment system and combine
with the IWTP-treated effluent prior to discharge. The effluent is discharged to the Cape Fear River
(National Pollutant Discharge Elimination System [NPDES] Permit NC0003719) and/or to the
City of Fayetteville Public Works Commission (PWC) publicly owned treatment works (POTW),
covered under Significant Industrial User Discharge Permit #2116RF.
The DAK and DuPont process wastewater is regulated under Title 40 Code of Federal Regulations,
Part 414 (40 CFR 414) — Organic Chemicals, Plastics and Synthetics Fibers Category (OCPSF). The
PET bottle recycle wastewater is not subject to federal categorical standards.
The IWTP is a conventional activated sludge biological treatment system. The plant was designed
for a flow rate of 1.25 million gallons per day (MGD); although other specific process design
information is not available. The system contains two separate aeration basis, with volumes of
1.2 MG and a 4.4 MG, or a total of 5.6 MG of aeration capacity. EnSafe understands after the
closure of the Monsanto facility, the 4.4 MG aeration basin was taken offline and idled due to the
decrease in flow rate.
The characteristics of the PET bottle recycle wastewater are significantly different than the
organic chemical wastewater currently generated. Based on a literature review of the
general characteristics of this wastewater; the main differences relative to the existing
organic chemical wastewater are:
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E!iisAFE
Biological System Assessment Report
DAK Americas, LLC
Fayetteville, North Carolina
November 2009
• High pH;
• High Total Suspended Solids (TSS);
• High Total Dissolved Solids (TDS);
• Presence of non-ionic surfactants; -
• Presence of particulate chemical oxygen demand (COD); and
• Higher temperature
Considering the different characteristics, the PET bottle recycle wastewater will be pretreated
prior to discharge to the existing IWTP. A detailed discussion of the pretreatment system is
provided in the Pretreatment System Engineering Report (September 2009). The main
treatment objectives of the pretreatment system are equalization, pH neutralization and
TSS removal, in particular fixed (or inert) suspended solids' which are not readily biodegradable.
The TSS contains a high percentage of volatile suspended solids (VSS) which are expected to be
relatively biodegradable based on a literature review.
The assessment consisted of a biological treatability study to assess the treatability of the
pretreated PET bottle recycle wastewater blended with the existing wastewater at a ratio based on
the projected flow rates provided by CPR and the 2006 to 2008 daily average flow rate. For this
assessment, six bench -scale biological reactors were operated for a period of approximately
7 weeks. Analytical data sheets are included on a CD provided with this report.
1.2 NPDES Permit
In accordance with the terms and conditions of the existing NPDES permit, DAK applied for a
NPDES permit renewal that included the estimated flow contribution from the proposed
PET bottle recycling facility. EnSafe received a copy of this permit from DAK in August 2009. A
copy of the permit and rationale is provided as Appendix A.
Based on a preliminary review of this permit, EnSafe understands the following:
• The permitted flow rate remains 0.500 MGD as a monthly average.
• A 2-year permit was issued that expires on October 31, 2011.
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Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
• The North Carolina Department of Environment and Natural Resources — Division of Water
(NCDENR) denied the request to include the PET bottle recycle wastewater in recalculating
permit limits, effectively allocating "zero" biochemical oxygen demand (BOD) and TSS to
this new wastestream.
• It appears the NCDENR calculated mass -based BOD and TSS permit limits using "only" the
OCPSF long-term average flow of 0.228 MGD, and using the daily maximum and
monthly average concentration limits for BOD (64 milligrams per liter [mg/L] and 24 mg/L,
respectively) and TSS (130 mg/L and 40 mg/L, respectively) in 40 CFR 414, Subpart D. For
BOD, these values were used to calculate seasonal mass -based limits from April 1 to
October 31 (i.e., warm season); then these warm season BOD limits were doubled to
calculate the seasonal mass -based limits for the cool season (November 1 to March 31).
TSS Limits
TSS Daily Maximum: 130 mg/L x 0.228 MGD x 8.34 = 247 pounds per day (lbs/day)
TSS Monthly Average: 40 mg/L x 0.228 MGD x 8.34 = 76 pounds per day
BOD Warm Season Limits (April 1 to October 31)
BOD Daily Maximum: 64 mg/L x 0.228 MGD x 8.34 = 122 pounds per day
BOD Monthly Average: 24 mg/L x 0.228 MGD x 8.34 = 46 pounds per day
BOD Cool Season Limits (November 1 to March31)
BOD Daily Maximum: 122 pounds per day x 2 = 244 pounds per day
BOD Monthly Average: 46 pounds per day x 2 = 92 pounds per day
• With this NCDENR permitting approach (i.e., "zero" BOD and TSS allowance for the
PET bottle recycle wastewater), as the discharge flow rate increases the required BOD and
TSS effluent concentration to meet the mass -based limits decreases proportionally.
As an example, the estimated effluent BOD and TSS concentrations that would be required
to meet the mass -based limits as a function of effluent flow are provided in Table 1.
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ENSAFE
Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
7.0 CONCLUSIONS AND RECOMMENDATIONS
EnSafe prepared this biological treatment assessment report to assess the potential impact of the
discharge of the pretreated bottle recycle wastewater to the existing conventional activated
sludge treatment system, and to assess if the existing activated sludge system has the capacity to
treat the increased. COD loading.
The existing system contains two separate aeration basis, with volumes of 1.2 MG and 4.4 MG, or a
total of 5.6 MG of aeration capacity. At the current COD loading, only the 1.2 MG aeration basin is
utilized for treatment. The 4.4 MG aeration basin was idled several years ago due to the decrease
in COD loading after the Monsanto plant closure. A central objective was to determine if the
1.2 MG aeration basin can handle the increased COD from the bottle recycle wastewater for the
three flow scenarios considered (Phase I Start -Up, Phase I, Phase II).
The pretreated bottle recycle wastewater has significantly different characteristics, compared to the
existing organic chemical wastewater; in particular higher TDS, higher TSS, more non-ionic
surfactants, higher projected temperature, and higher pH. The TSS concentration from the
pretreatment plant is expected to vary between 100 to 600 mg/L on average; Based on the
unit process utilized for solids removal at the pretreatment system, it is envisioned the effluent TSS
will be primarily the finer fraction of the TSS (i.e., assumed large plastic -type solids removed),
which for the purpose of this assessment was assumed to be all biodegradable VSS that exerts a
COD demand.
The assessment included a study to assess the biological treatability of the pretreated bottle
recycle wastewater (40% by volume) blended with the existing wastewater (60% by volume).
Two different conditions of PET bottle recycle wastewater were simulated: fully treated —
representing an effluent condition of low TSS, and partially treated — representing an estimated
effluent TSS condition on the order of about 900 mg/L. This TSS concentration was assumed as
a maximum.
The projected range of bottle recycle wastewater effluent COD concentrations used in this
assessment are summarized as follows:
• Best Case: Total COD of 1,890 mg/L (assumed TSS of 100 mg/L)
• Worst Case: Total COD of 5,000 mg/L (assumed TSS of 900 mg/L)
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ENSAFE
Biological System Assessment Report
DAK Americas, LLC
Fayetteville, North Carolina
November 2009
For the existing facility wastewater, the 2006 to 2008 average existing facility wastewater average
flow rate of 170,000 GPD and average COD of 2,560 mg/L (or 3,639 Ibs/day) were assumed for
this assessment.
A review of the historical data indicated that the COD concentration from 2006 to 2008 was
relatively consistent, with a 3-year maximum monthly average concentration of 3,553 mg/L
(or 5,037 Ibs/day at 0:170 MGD).
During the course of the treatability study, EnSafe observed that the existing facility wastewater
COD concentrations were much higher than historical data; however, at that time the difference
was not understood. During preparation of this report and a review of the actual wastewater
operational logs for June and July 2009, the plant records also indicated much higher influent
COD concentrations, generally in the same range as EnSafe testing data. Thereafter, EnSafe
learned that a unit process upset condition occurred during this period, which resulted in
significantly higher COD loadings. The average COD measured by EnSafe during the study was
5,800 mg/L. EnSafe understands a repair of the unit process upset requires a plant shutdown;
therefore, higher COD loading will continue for some time. Based on discussions with DAK;
EnSafe understands that this higher COD loading condition is likely to persist after start-up of the
bottle recycle plant.
Therefore, as a result, EnSafe evaluated two conditions based on COD concentration for the
existing facility_ wastewater, assumed to represent the average case and peak case.
• Average Existing Facility Loading: Total COD 2,560 mg/L (3,629 Ibs/day)
• Peak Existing Facility Loading: Total COD 5,800 mg/L (8,223 Ibs/day)
For this assessment, three discharge scenarios were evaluated based on the projected bottle
recycle wastewater flow rate. These discharge scenarios were developed based on information
provided by CPR and are summarized as follows:
• Phase I Start -Up: 2,000 kg/hour production capacity: 58,500 GPD
• Phase I: 7,000 kg/hour production capacity: 201,000 GPD --
• Phase II: 12,000 kg/hour production capacity: 347,600 GPD
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ENSAFE
Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
Summary of Cases Evaluated
Using this information, the following case scenarios were developed and evaluated, based on the
bottle recycle flow rate and the range of possible COD concentrations assumed for each
wastestream to determine a COD loading. The cases and associated COD loading are summarized
in Table 33. In all cases, the 2006 to 2008 average daily existing facility wastewater flow rate
was utilized.
Table 33
Summary of Cases Evaluated
PET Flow Case Al Case A2 Case Bi Case B2
Rate COD COD COD COD
Case Scenario (GPD) (Ibs/day) (Ibs/day) (Ibs/day) (Ibs/day)
Existing Wastewater COD (mg//L) 5,800 5,800 2,560 2,560
PET Wastewater COD (mg/L) 5,000 1,890 5,000 1,890
Phase I Start -Up 58,500 10,337 9,020 5,740 4,430
Phase I 201,000 - 15,625 11,020 11,030 . 6,430
Phase II 347,600 20 900 13,020 16,040 8,420
i
Biokinetic and Oxygen Use Coefficients
From the treatability study, biokinetic and oxygen use coefficients were estimated for the
40%/60% blend of the fully pretreated bottle recycle wastewater and existing facility wastewater
based on soluble COD. The estimated coefficients are summarized as follows:
Specific substrate utilization rate constant (K) = 0.00012 L/mg hour
Yield Coefficient (Y) = 0.46 mg VSS/mg VSS
Aerobic Decay Coefficient (Kd) = 0.077 per day
Oxygen Use Coefficient for Synthesis (A) = 0.66 Ib 02/Ib COD
Oxygen Energy of Maintenance Coefficient (B) = 0.0072 Ib 02/Ib VSS day
For the case scenarios developed, these coefficients were then used to predict the steady state
VSS concentration in the aeration basin and the oxygen requirement.
Although these coefficients were developed for the 40%/60% blend of fully pretreated bottle
recycle wastewater and existing facility wastewater and are based on soluble COD, they were
utilized in all case scenarios. This approach was assumed valid based on a comparison of data
obtained from the reactors. This direct comparison of data suggests that the slowly degrading
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Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
soluble COD in the existing facility wastewater is controlling and the rate of hydrolysis of particulate
COD is less than the rate of substrate utilization of the slowly degrading COD.
Reactor Operational Results
The reactor operation results indicated essentially complete removal of the soluble readily
biodegradable COD and CBOD at a sludge age of about 70 days. This is consistent with the
operational sludge age in the plant. This result, in conjunction with the estimated substrate
utilization rate, suggests that at a 40%/60% blend, the fully treated bottle recycle wastewater was
amenable to treatment and did not negatively impact the removal of the slowly degrading organics
in the existing facility wastewater at a sludge age of 70 days.
By direct comparison of the results from the fully treated reactor to the partially treated reactor
operated at about the same sludge age, the particulate COD was predominately solubilized
and biodegraded.
The settling characteristics of the mixed liquor produced in the reactors fed with fully pretreated
bottle recycle wastewater/existing facility wastewater blend were worse, when compared to the
control reactor operating at approximately the same sludge age, as indicated by SVI. SVI values
for the fully pretreated bottle recycle wastewater/existing facility wastewater blend averaged
231 ml/g; however, values between 300 to 350 ml/g were observed during the study.
Alternatively, the mixed liquor in the reactor fed with partially pretreated bottle recycle wastewater
receiving TSS/VSS in the pretreated effluent settled very well, in fact, better than the control
reactor. It is speculated the fine solids present in the bottle recycle wastewater acted as a
settling aid and improved settling performance. This data suggests the presence of solids in the
pretreated effluent is advantageous and appears to enhance settling.
Total Dissolved Solids
At the 40%/60% blend, based on the rounded average of the TDS concentrations of each
individual wastestream (500 mg/L existing facility . wastewater, 5,000 mg/L bottle recycle
wastewater) the estimated blended TDS concentration was about 2,300 mg/L. Therefore, the
overall substrate utilization rate constant is specific to this TDS concentration. Higher
TDS concentrations may reduce the overall substrate utilization rate. Some literature references
indicate a significant reduction in the overall substrate utilization rate as the TDS concentration
increases above 0.5% (or 5,000 mg/L).
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Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
For the Phase II condition, the projected percentage is 67% bottle recycle wastewater and 33%
existing facility wastewater, which at the aforementioned conditions indicates a blended
TDS concentration of about 3,500 mg/L (or about 0.35%). This TDS condition was not evaluated
in the treatability study, but it is reasonable to assume the overall substrate utilization rate could
decrease as the TDS concentration increases impacting performance. Additionally, as the TDS
increases, the oxygen transfer rate and biomass settl 9 may be negatively affected.
Case Assessment Summary
For the case scenarios presented, the aeration basin temperature, projected aeration basin
MLVSS concentration, and oxygen requirement were estimated, assuming operation in either the
1.2 MG or the 4.4 MG basin at a sludge age of 70 days.
Operational risks were identified based on the following conditions:
• Aeration basin temperature of greater than 35 °C
• MLVSS concentration outside of 1,000 to 4,000 mg/L
• Oxygen requirement greater than oxygen available
For the Phase II bottle recycle flow rate, regarding aeration basin temperature, assuming the
2006 to 2008 peak monthly average temperature in the existing facility wastewater, along' with a
bottle recycle wastewater temperature at the discharge of the equalization tanks of 45 °C, it is
apparent that the maximum allowable activated sludge temperature of 35 °C would be exceeded in
the 1.2 MG aeration basin during the peak month. Therefore, in the current configuration, the
r 1
1.2 MG aeration basin would not be viable for Phase II based on projected temperature.
Case A: Upset COD Loading, Existing Facility Wastewater at Total COD = 5,800 mg/L
It is clear from this analysis that if the existing wastewater COD remains at 5,800 mg/L, the 1.2 MG
basin is not adequate to handle the increased COD Toad from the bottle recycles wastewater,
even during the Phase I Start -Up condition, regardless of the COD concentration in the bottle
recycle effluent.
Under this scenario, operation in the 4.4 MG basin would be required. The aerators installed in this
basin (900 HP) appear to have sufficient aeration capacity for practically the full Phase I condition
over the range of effluent COD concentrations evaluated, although conditions approach marginal
(an estimated 910 HP required) if both the existing facility wastewater influent (COD at
5,800 mg/L) and the PET wastewater influent (COD at 5,000 mg/L) were to remain at their
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Biological System Assessment Report
DAK Americas, LLC
Fayetteville, North Carolina
November 2009
worst case condition for several days. Using the discounted oxygen transfer efficiency and the
conservative oxygen transfer coefficient, the aeration assessment may tend to overestimate the
aeration required; however, it is reasonable to assume additional aeration would be necessary. It
is recommended that data be collected during start-up to confirm estimated aeration requirements.
If these are confirmed and it is found that existing DAK wastewater and the PET effluent
wastewater are likely to have CODs near their worst case conditions, additional aeration in the
4.4 MG basin for Phase I would be warranted to allow for equipment downtime and transient
peak loads.
Case B: Historical COD, Existing Facility Wastewater at Total COD = 2,560 mg/L
For Case B, the three flow scenarios for the bottle recycle wastewater were evaluated at the range
of possible bottle recycle COD concentrations from 1,890 mg/L to 5,000 mg/L.
Phase I Start -Up Condition
For the Phase I start up condition (58,500 GPD bottle recycle wastewater), the estimated
COD loading is presumed to vary from 4,430 to 5,740 Ibs/day over a bottle recycle
COD concentration of 1,890 to 5,000 mg/L.
1.2 MG Aeration Basin
Based on the temperature assessment, assuming a bottle recycle wastewater discharge
temperature of 45 °C, the projected aeration basin temperature during the peak month was
estimated at 32.5 °C to 34.9 °C, which is within the acceptable range; however, this indicates
a practical maximum temperature limit for the bottle recycle wastewater of 45 °C during the
start-up phase.
Based on the VSS concentration assessment, the estimated MLVSS concentration is the 1.2 MG
aeration basin is 2,920 to 3,582 mg/L (allowing for the 700 mg/L adjustment), over a bottle recycle
COD concentration of 1,890 to 5,000 mg/L. This is a reasonable MLVSS concentration range and
within the limits of the clarifier.
Based on the aeration assessment, the 405 HP of aeration capacity would be adequate for the
range of expected conditions.
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Biological System Assessment Report
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Fayetteville, North Carolina
November 2009
44 MG Aeration Basin
The estimated MLVSS concentration in the 4.4 MG aeration basin was projected at 1,306 to
1,486 mg/L (allowing for the 700 mg/L adjustment), over a bottle recycle COD concentration of
1,890 to 5,000 mg/L. This is a fairly low MLVSS concentration and settling performance could be
negatively impacted.
For the Phase I start-up condition, operation in the 1.2 MG basin is recommended.
Full Phase I Condition
For the full Phase I condition (201,001 GPD bottle recycle wastewater), the estimated COD loading
is presumed to vary from 6,427 to 11,031 Ibs/day, over a bottle recycle COD concentration of
1,890 to 5,000 mg/L.
1.2 MG Aeration Basin
Based • on the temperature assessment, assuming a bottle recycle wastewater discharge
temperature of 45 °C, the projected aeration basin temperature during the peak month was
estimated at 37.2 °C to 38.7 °C, which is above the practical maximum allowable for the activated
sludge process of 35 °C.
Again, temperature estimation was based on a simplistic approximation and actual temperature in
the 1.2 MG basin may be less; however, this assessment indicates that for the full Phase I
condition, the bottle recycle wastewater temperature maximum would most likely need to be Tess
than 45 °C at the discharge to the existing equalization tanks, probably on the order of 40 to 41 °C;
otherwise, additional surface aerators may be needed to provide cooling to control the aeration
basin temperature to less than 35 °C for the peak month.
Based on the VSS concentration assessment, the estimated MLVSS concentration is 3,921 to
6,289 mg/L (allowing for the 700 mg/L incremental adjustment), over a bottle recycle
COD concentration of 1,890 to 5,000 mg/L. This indicates that at the higher end of the expected
range of the bottle recycle COD concentrations evaluated, the MLVSS would exceed the desired
range, which appears could result in settling issues.
Based on the aeration assessment, using the discounted transfer efficiency and the conservative
oxygen transfer coefficient, the existing 405 HP of existing aeration capacity would be adequate for
the best case 1,890 mg/L COD concentration in the bottle recycle wastewater; however up to an
additional 250 HP of additional aeration capacity could be required at the worst case of 5,000 mg/L
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Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
in the bottle recycle wastewater. As discussed, this aeration assessment may overestimate the
amount aeration required; however, it is clear that additional aeration is required for operation in
the 1.2 MG aeration basin for the Phase I condition.
For the Phase I condition, operation in the 1.2 MG aeration basin is marginal. For this to be
possible, the effluent COD from the bottle recycle plant would need to be near the optimum of
1,890 mg/L, with the existing facility wastewater at 2,560 mg/L.
Considering these three factors, combined with the inability to handle peak loading or
upset conditions with high COD in the existing facility wastewater for the full scale Phase I
condition, operation in the 4.4 MG basin is recommended and operation in this basin was assessed.
4.4 MG Aeration Basin
As discussed, estimating the amount of cooling for the Phase I flow rate in the 4.4 MG basin was
beyond the scope of this project. However, given the higher surface area compared to the 1.2 MG
aeration basin and number and size of surface aerators, the amount of heat loss is envisioned to be
higher than the 1.2 MG basin. It is recommended the actual bottle recycle wastewater temperature
be determined during the start-up condition and a detailed heat balance assessment be conducted.
Based on the aeration assessment, using the discounted transfer efficiency and the conservative
oxygen transfer coefficient, the existing 900 HP of existing aeration capacity would be adequate to
meet even the estimated demand of 650 HP for the worst case COD of 5,000 mg/L in the bottle
recycle wastewater.
Phase II Condition
For the Phase II condition (347,600 GPD bottle recycle wastewater), the estimated COD loading is
presumed to vary from 8,420 to 16,040 Ibs/day, over a bottle recycle COD concentration of
1,890 to 5,000 mg/L.
As discussed, for the Phase II flow rate, operation in the 1.2 MG aeration basin is not possible from
a temperature, MLVSS and available aeration standpoint.
4,4 MG Aeration Basin
As discussed, estimating the amount of cooling for the Phase II flow rate in the 4.4 MG basin was
beyond the scope of this project. It is recommended temperature data be collected during Phase I
Start-Up/Phase I operation and a detailed heat balance assessment be conducted prior to Phase II.
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Biological System Assessment Report
DAK Americas, LLC
Fayetteville, North Carolina
November 2009
Based on the VSS concentration assessment, the estimated MLVSS concentration is 1,851 to
2,933 mg/L (allowing for the 700 mg/L incremental adjustment), over a bottle recycle
COD concentration of 1,890 to 5,000 mg/L. This is a reasonable MLVSS concentration range.
Based on the aeration assessment, using the discounted transfer efficiency and the conservative
oxygen transfer coefficient, the existing 900 HP of existing aeration capacity would become
marginal i e o e recyc e e uent COD concentration approached its -worst case. Furthermore,
there would be no reserve aeration capaci o meet transient peaks or allow for
equipment downtime. It is recommended that wastewater oadin s and aeration performance be
monitored during Phase I. If the conclusions and assumptions of this study are confirmed,
additional aerators would be warranted in the 4.4 MG basin prior to Phase II. It appears that this
projected aeration requirement could be met by relocating the two floating Aire-02 aerators from
the 1.2 MG basin.
Other Conclusions
In addition, the following conclusions are provided based on knowledge of plant operations, a
review of the permit, and the characteristics of the bottle recycle wastewater. Some of these
conclusions were previously presented in the Pretreatment System Engineering Report.
• For the projected Phase I condition, there appears to be a risk of exceeding the 0.500 MGD
monthly average flow limit during a peak monthly condition with the stormwater
contribution. For the projected Phase II flow conditions, the projected daily average flow
rate will exceed the 0.500 MGD monthly average flow limit.
• The permitting approach selected by the NCDENR results in decreasing concentration limits
(BOD, TSS, and ammonia) with flow, as no specific allocation was made for the
CPR discharge. Using the combined projected Phase I flow rate and the 2006 to 2008
average facility flow rate (0.371 MGD), the estimated monthly average warm season BOD,
TSS, and warm season ammonia concentration limits are 14.8 mg/L, 24 mg/L, and
4.2 mg/L, respectively.
• Considering the reduced ammonia limit, EnSafe recommends an upgrade to the existing
nutrient feeding system and nutrient control program to achieve a more balanced
nutrient addition, relative to COD loading.
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£NSAFE
Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
As a nitrogen supplement, EnSafe understands urea is dosed directly to the pH pit. The pit
is relatively quiescent, with no mechanical mixing. The amount of urea added is based on
the influent COD (measured once per day). Urea appears to be added at a ratio of about
5 Ibs of nitrogen per 100 Ibs of influent COD. Also, EnSafe understands the nutrient
metering rate may be adjusted (or trimmed) based on the effluent ammonia residual.
This method is effectively a daily average feedback type nutrient control strategy, where
nutrients are added based on the previous day average COD loading. EnSafe suggests that
a more reliable nutrient strategy be developed which will more closely match nutrient
requirements with actual organic loading.
• The measured TDS in the DAK wastewater (about 500 mg/L) compared to pretreated bottle
recycle wastewater (4,840 mg/L to 5,500 mg/L) is significantly different. The system should
be operated to minimize short-term changes in TDS concentration, as this could negatively
impact performance.
• The measured CTAS surfactant concentration in the fully pretreated and partially pretreated
wastewater ranged from 120 to 110 mg/L. The results for the biological treatability study
indicated a projected effluent concentration of 10 to 20 mg/L, indicating some residual CTAS
surfactant was present in the discharge and not fully biodegraded. During the
treatability study, some foaming was observed in the effluent upon agitation, suggesting
some residual surfactant may be present. Obviously, the treatability study was performed
using the wastewater samples provided by CPR, in which those specific surfactant(s) used in
the process chemistry were not known. EnSafe recommends that CPR select surfactant(s)
that are readily biodegradable. Additionally, CPR should evaluate the aquatic toxicity data
of the proposed surfactant(s) and select a surfactant with low aquatic toxicity.
• Foaming may be an issue in the final effluent and foam control may be necessary.
• The pretreatment system effluent is proposed for discharge to the existing equalization
tanks (or to a single tank). The effluent from the pretreatment system will contain residual,
relatively fine solids. Although residual TSS/VSS is of a small particle size, it will settle over
time and could cause maintenance issues in this tank if not agitated. EnSafe recommends
mixing be considered in this tank.
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ET�JSAFE
Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
• The total phosphorus in the bottle recycle wastewater sample was measured at 12.8 mg/L;
however, the indicated process chemical contained 5 to 7% phosphorus. If a
process chemistry with a high phosphorus concentration is used, this could be a concern for
discharge to PWC, with a total phosphorus permit limit of 3.0 mg/L. Although there is not a
proposed phosphorus limit in the current NPDES permit, phosphorus is a "report only"
parameter. Therefore, this provides for the possibility of a future phosphorus limit, should
effluent data indicate concentrations of concern.
Recommendations
EnSafe understands that the Phase I Start-up condition (2,000 kg/hr production at 58,500 GOD) is
planned for spring 2010, with the full Phase I condition (7,000 kg/hr production at 210,000 GPD)
planned for late 2010.
Based on this information, it appears there is about 6 to 8 months between Phase I Start -Up and
full Phase I.
Assuming that the unit process upset condition is repaired and the existing facility wastewater COD
is at historical conditions, the existing 1.2 MG basin is adequate both volumetrically and in terms of
aeration capacity to treat the Phase I Start -Up bottle recycle wastewater over the range of
wastewater conditions evaluated (COD of 1,890 mg/L to 5,000 mg/L).
Therefore, EnSafe recommends initial operation in the 1.2 MG aeration basin during this period.
The 6 to 8 month timeframe could be utilized to obtain actual data on the characteristics of the
bottle recycle effluent and actual discharge rates, along with a better understanding of the
possible reduction in oxygen transfer efficiency in the aeration basin.
This would allow a more accurate assessment of the capacity of the 1.2 MG basin capacity for the
full scale Phase I condition. As discussed, based on the current information provided by CPR on
projected flow rates and estimated loading, operation in the 1.2 MG basin is at best marginal, and
additional aeration capacity is necessary; therefore is not recommended. However, if actual
COD loading from CPR is Tess; either due to lower wastewater discharge rates than assumed
(for this assessment bottle recycle wastewater flow based on 4 L/kg, however originally 2.5 to
3.0 L/kg was proposed) or lower COD concentrations than projected, operation in the 1.2 MG might
be possible for the Phase I condition. A reassessment could be conducted based on actual
operating data.
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Biological System Assessment Report
DAKAmericas, LLC
Fayetteville, North Carolina
November 2009
If the unit process upset condition is not repaired prior to initiation of CPR discharge or the Phase I
operational period is not available for actual full scale data collection, EnSafe recommends
operating in the 4.4 MG basin and making provisions to provide up to 150 HP of additional aeration
prior to Phase II. At this time, based on current information, it appears that this projected aeration
requirement could be met by relocating the two floating Aire-02 aerators from the 1.2 MG basin.
Prior to receipt of bottle recycle wastewater in the existing system, a start-up plan needs to
be developed for acclimation of the biomass to the different characteristics of the bottle
recycle wastewater.
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