NC0005762_Facility POA_20030926

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WESTPOINT STEVENS
September 26, 2003
Ms. Belinda Henson
North Carolina Department of Environment & Natural Resources
Division of Water Quality
225 Green Street, Suite 714
Fayetteville, NC 28301
Re: WestPoint Stevens — Bob Stevens Plant
Wagram, Scotland County
NPDES Permit No. NC0005762
Dear Ms. Henson:
EP 3 0 2003
As you know, we have been battling a persistent filamentous bacteria problem at our Bob
Stevens Plant for some time. Although we have been able to stay in compliance
throughout most of this period, we have experienced poor settling and some solids
carryover. We have tried various ways to deal with this situation, including polymer
addition to improve settling, chlorination of the biomass to treat the bacteria, dredging the
equalization basin (twice) to remove possible sources of organic acids that promote
filamentous growth, and reducing the biomass concentration in the aeration basin. While
these measures have been successful in the short term, the filamentous bacteria always
return. Although the effluent suspended solids have remained within permitted limits
until the most recent episode last week, we have noticed an increasing incidence of fecal
Coliform violations that also seem to be related to this chronic poor settling situation.
Earlier this week, we retained an expert on textile wastewater treatment to review our
operation and to hopefully discover why we have been unsuccessful in eliminating the
filamentous bacteria problem. Edwin Barnhart has studied textile wastewater treatment
for many years and is recognized worldwide as an expert in the field. Attached is a letter
that he wrote following his visit to our facility last Tuesday. His conclusion was that the
most likely cause of the chronic filamentous problem is the current Food -to -
Microorganisms (F:M) Ratio.
In our operation, the greatest contributor to the load on our treatment plant is the
"desizing" step. Prior to weaving, the yarn that makes up all of our woven material is
coated with a sizing material to give it extra strength and smoothness to help resist
breaking during the weaving process. The first step in finishing is to wash all of this
sizing material off the fabric. This process produces probably 60% of the total load on the
treatment plant.
POST OFFICE BOX 71, 507 W. 10TH STREET, WEST POINT, GEORGIA 31833 • AREA 706 645-4000

For many years, this sizing material was composed mostly of starch, which is readily
biodegradeable. Recently, some of the starch has been replaced by polyvinyl alcohol
(PVA), which is a more effective sizing material but one that is harder to biodegrade. Mr.
Barnhart is very familiar with the properties of PVA, having performed the treatability
studies for DuPont before they put it on the market several years ago. After reviewing our
operating information, he concluded that our F:M ratio was too high. While plants can
operate at this F:M level, it promotes the growth of organisms that are susceptible to
upset given the nature of our current influent. The plant could handle mostly -starch sizing
at this higher F:M but could show erratic results with PVA.
He recommends that we undertake to raise our MLSS level so as to drop the F:M ratio to
around 0.20. This could be done by eliminating solids wasting until the desired F:M was
reached but the process could take several months. As a quicker alternative, he
recommended that we transfer sludge from our aerobic digester back to the aeration
basin. Although this sludge is marginally active, it will provide additional structure to
promote improved settling and enhance the growth process.
During his visit, we also studied our current method of chlorination used to treat the
filamentous bacteria. We have identified a different location to add the chlorine - one that
we believe will allow us to do a more effective job with a lower dose rate. This should
improve our filamentous kill with less damage to the beneficial bacteria.
Both of these measures will be gradually implemented within the next few days. During
this process, we will closely monitor the system for any problems that might develop.
The plant will use polymer as necessary to improve settling until the desired operating
conditions are achieved. We believe that this approach will reduce the filamentous
bacteria problem, improve the treatment efficiency, and result in a more stable system
that is less susceptible to upset. If you have any comments or wish to discuss this
approach before we begin, please give me a call at 706-645-4515.
Sincerely,
k_
OZAJ
Eddie Lanier, P.E.
Director — Environmental Department

Edwin L. Barnhart, LLC
922 Stone Crab Cove
Fripp Island, SC 29920
ph. 843 838 5378
Fax [phone]
September 24, 2003
Mr. Yancy D. Helton
Director of Engineering
Westpoint Stevens
P.O. Box 388
Wagram, NC 28396
Dear Mr. Helton,
I enjoyed the opportunity to visit with you and review the operation of your waste trcatment
plant. Wagram has a very good treatment facility that is well run by your staf. In our discussions
you indicated that the plant has had some recurring problems with solids settling and I have
reviewed the plant data in an attempt to identify the possible causes of these problems. Although
many factors may contribute to the settling problems I believe that the main problem is the loading
conditions at which the plant is presently operating.
In the past the main size used in the manufacturing process was starch. At present the plant is
using much more PVA. An approximate analysis of the data you provided indicates that the COD
loading to the plant is now about 42 % from PVA and I8 % from starch. This shift in waste
composition requires an adjustment in the mode in which the plant is operated. The main plant
criteria that must be adjusted is the Food /Microorganism ratio [F/Mj_
While a plant treating starch waste can operate at a high F/M, experience has shown that to
successfully treat a stream high in PVA an F/M of less than 0.24 is necessary. It is desirable
to maintain the F/M in the range of 0.18 to 0.20. The plant is presently operating with an F/M of
greater than 0.35. The settling problems are, in large part, a result of this operating condition. In
order to provide sufficient biomass to operate at the desired F/M level the MLSS in the aeration
basin should be in the order of 40Q0 mg/l. The basin is presently operating below 2000 mg/I.
The increase in MLSS can be accomplished two ways: through eliminating solids wasting or
through direct addition of additional solids. Allowing the solids level to increase through
elimination of solids wasting is a slow process and could take several months to reach the desired
level. During that time the system will be somewhat unstable and continued attention to settling
will be required.. This will be time consuming and costly.
As an alternative, solids from the aerobic digester can be added back to the system. Returning 0.3
MG of concentrated solids should raise the MLSS by about 1600 mg/l. This addition could be
accomplished by returning 0.75 MG/day for four days. The additional solids needed to reach the

Edwin L. Barnhart, LLC
desired operating level can be accumulated by eliminating wasting until the desired level is
rcached.
It is not anticipated that the solids returned from digestion will be highly active but the sludge
matrix will provide a structure that will aid settling and enhance the growth process. This should
shorten the time needed to bring the plant to optimum operation and make the transition easier.
This is the course of action I recommend.
Adjusting the F/M in the plant should improve settling and lower the effluent COD , resulting in
more stable operation. After this adjustment is place it will be possible to determine if any other
factors are also impacting the stability of the system.
I trust that upon review you will concur with my conclusions. If you have any questions or
comments please let me know.
Sincerely,
Edwin L. Barnhart