WATER POLLUTION CONTROL RESEARCH SERIES  12060 EOE 01/72
       Water Pollution Reduction
  Through  Recovery of Desizing Wastes

U.S. ENVIRONMENTAL PROTECTION AGENCY

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                   WATER POLLUTION OONTBDL EESEARCH SERIES

The Water Pollution Control Research Series describes the results and progress
in the control and abatement of pollution in our Nation's waters. They provide
a central source of information on the research, development, and demonstration
activities In the Environmental Protection Agency, through inhouse research and
grants and contracts with Federal, State, and local agencies, research institutions
and industrial organizations.

Inquiries pertaining to Water Pollution Control Research Reports should be
directed to the Head, Publications Branch (Water), Research Information
Division, MM, Environmental Protection Agency, Washington, B.C. 20460.

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        WATER  POLLUTION  REDUCTION
                    THROUGH
       RECOVERY OF  DESIZ1NG WASTES
                        by
       DEPARTMENT OF TEXTILE CHEMISTRY
               SCHOOL OF TEXTILES
        NORTH CAROLINA STATE UNIVERSITY
          RALEIGH, NORTH CAROLINA  27607
                      for tke
        ENVIRONMENTAL PROTECTION AGENCY

        OFFICE OF RESEARCH AND MONITORING
                 Project 12090 EOE

                   January 1972
For sale by tho Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price 60 cants

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                   EPA Re view-. Notice
This report has been r&viev/ed by the Environmental Protec-
tion Agency and approved for publication.  Approval does
not signify that the contents necessarily reflect the
views and policies of the Environmental Protection Agency,
nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
                           11

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                               ABSTRACT
Processes for precipitating from desizing wastes the synthetic warp sizes,
carboxymethyl cellulose ( CMC) and polyvinyl alcohol ( PVA) , were
investigated.   Carboxymethyl cellulose is precipitated quantitatively by
certain multivalent metal salts, such  as  aluminum  sulfate and ferric
chloride.  Aluminum sulfate is  the more suitable for size recovery.

Cycles  of sizing,  desizing and size recovery were performed on cotton-
polyester ( 65:35)  yarns, starting with commercial CMC, and continuing
with only the recovered material.  After four cycles, the performance
of the recovered CMC  on a Callaway slasher was satisfactory and results
with the sized yarns on a warp-shed tester were equivalent to results with
yarns sized with new CMC.

Two copolymers of PVA were prepared,  one of which was precipitated
from dilute solution by aluminum sulfate and ferric chloride, the other
by acidification.  Preliminary sizing trials with small samples of mater-
ials  indicate that these,  or similar, copolymers may be effective,  recovera-
ble warp sizes.

Evidence was obtained that acclimatization of sewage bacteria to CMC and
PVA occurs upon prolonged contact in a laboratory activated-sludge unit.

This report was submitted in fulfillment  of Project 1Z090 EOE under the
sponsorship of the Water Quality Office,  Environmental Protection  Agency.

Key words: acclimatization, alum,  carboxymethyl cellulose, industrial
wastes,  pollution abatement, polyvinyl alcohol, precipitation,  reuse,
textiles, warp sizes.
                                    111

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                                CONTENTS

Section                                                          Page
 I.   Conclusions		        1

II.   Recommendations	        3

III.  Introduction		        5
       Background Information	        5
       Recovery Methods	        6
       Scope and Purpose  of Project	        6

IV.  Studies and Discussion	        7
       Recovery and Reuse of Carboxymethyl
          Cellulose ( CMC)	        7
       Recovery of Polyvinyl Alcohol ( PVA)
          from  Desizing Wastes	       16
       Removal of Desizing Products of Starch from
          Desizing Wastes   	       17
       Biodegradation of Carboxymethyl Cellulose (  CMC) ...       20
       Biodegradation of Polyvinyl Alcohol ( PVA)	       ZZ

 V.  Acknowledgement	       33

VI.  References	,	       35

VII.  Publications and Patents	       37

VIII.  Appendices	        39
        Appendix A - Laboratory Procedures	        41
        Appendix B - Related Literature	        47
                                  v

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                                 FIGURES

No.                                                              Page

1.  Chemical Equations for ( a) Precipitation of CMC
        with Filter Alum and ( b)  Solution of the Preci-
        pitate with Sodium Hydroxide	       8

2.  Chemical Transformations in the Preparation of
        PVA Copolymers	      18

3.  Treatment of CMC with Activated Sludge Developed
        in Laboratory	      24

4.  Removal of CMC with  Activated Sludge Developed
        in Laboratory	,	      25

5.  Treatment of CMC with Activated Sludge from Dan
        River Treatment Plant	      27

6.  Removal of CMC with  Activated Sludge from Dan
        River Treatment Plant  	      28

7.  Treatment of PVA with Activated Sludge Developed
        in Laboratory	      30

8.  Removal of PVA with Activated Sludge Developed
        in Laboratory	     31

9.  Laboratory Activated-Sludge Unit,  Consisting of
        Aeration Chamber  (A)  and Separation
        Basin  ( B)	     45
                                   VI

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                                  TABLES

 No.                                                           Page

 1.  Recovery of CMC by Precipitation with Filter
        Alum	      9-

 Z.  Sizing with CMC - New and Recovered	       10

 3.  Results from Warp-Shed Tester on Yarns Sized
        with  New and Recovered CMC	      12

 4.  Data on CMC Size Recovered by Precipitation	       13

 5.  Data on Supernatant from Precipitation of CMC Size. ...       14

 6.  Results from Warp-Shed Tester on Yarns Sized
        with  PVA and PVA Copolymers	      19

 7.  Synthetic Sewage Feed	      Zl

 8.  Removal of CMC with Activated Sludge Developed
        in  Laboratory	       23

 9.  Removal of CMC with Activated Sludge from Dan
        River Treatment Plant	       26

10.  Removal of PVA with Activated Sludge Developed
        in  Laboratory	       Z9
                                  VII

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                            SECTION I

                           CONCLUSIONS
1.  A process for recovering carboxymethyl cellulose  ( CMC) from
desizing wastes by precipitation with aluminum sulfate ( filter alum) has
been developed on a laboratory scale.  Considerable testing indicates
that the process may have practical applications.  The recovered CMC
may be suitable for reuse as a warp size; if not,  it may be disposed of
as a solid without further treatment.

2. A similar process for recovering  a modified polyvinyl alcohol
( PVA) from desizing wastes has been developed also, although it has
not been tested as thoroughly  as the CMC process.

3, An attractive procedure  was not found for recovering the conven-
tional warp-size-grade PVA from desizing wastes.  Recovery of thib
material by precipitation, without a prior concentrating step, does not
seem feasible.

4. Evidence was obtained that acclimatization of sewage bacteria
to CMC and PVA occurs upon prolonged contact in a laboratory activated
sludge unit.  The synthetic sizes then exhibit biodegradable characteristics,

5. A precipitation method for recovering the desizing products of
starch from desizing wastes was not found.

6. Examination of enzymatic desizing wastes, from starch-sized
fabrics,  obtained from a nearby textile plant, showed  that none of the
low-molecular-weight sugars was present.  The starch was degraded
to a more water-soluble material but  the degradation was only partial,
leaving products of molecular weights higher than those of the simple
sugars.

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                           SECTION II

                        RECOMMENDATIONS
1.  The process for precipitating CMC from desizing wastes should
be given further evaluation and development on a larger scale.  A
cooperative project, supported by  a Demonstration Grant, using
pilot-plant facilities located at an industrial plant,  with supporting
laboratory work at the University,  is recommended.

Z. In  recovering  CMC from desizing wastes, emphasis should be
placed on obtaining material suitable for reuse as a warp size.  Tests
on the  recovered material should be  made to determine the extent to
which  reuse is possible.

3.  The development of a process for the recovery from desizing wastes
of a warp size based on a modified PVA should be continued.   The  contem-
plated  method of recovery is similar to the coagulation and precipitation
scheme that was sucessful with CMC.  A satisfactory recovery procedure
should be followed by tests  on  the recovered  material to determine its
suitability for reuse as a warp size.

4. Other processes for recovering warp sizes from desizing wastes
should be investigated.  It is important that eagerness  to promote the
processes for recovering CMC and PVA does not lead to overlooking
other processes,  possibly employing new warp-size modifications,
which might turn out to be better.  An example would be to employ
as a warp size a polymer, such as methyl cellulose, which is  soluble
in water at room temperature  but insoluble in hot water; the size would
be applied and removed at room temperature and then precipitated and
recovered from the desizing waste upon heating.

5, Because of the exceedingly large amount  of starch used in  sizing
textile yarns,  further exploratory work should be carried  out on chemi-
cal and physical methods for removing the desizing products of starch
from desizing wastes.  Such methods should  be compared  with the usual
biological processes for removing  these products.

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                            SECTION III
                          INTRODUCTION
Background Information

Removal of the size with which the warp ( length-wise) yarns are coated
to make the weaving of the fabric possible is a common operation in the
preparation of cloth for dyeing  and finishing.  The basis of most warp
sizes for yarns of cellulose  ( cotton,  rayon)  and cellulose blends is
starch and modified starches.  These materials are biodegradable and,
because they are used in relatively large quantities -- 5 to 15$  of yarn
weight, amounting to over 300,000,000 pounds annually in this country,
contribute  heavily ( 45-70$ of total) to the biochemical oxygen  demand
( BOD-5)  of textile finishing wastes.

In recent years certain water-soluble,  synthetic polymers, with a much
lower BOD-5 than starch,  have been introducd for use as warp  sizes.  Of
these materials,  carboxymethyl cellulose ( CMC) and polyvinyl alcohol
( PVA) have gained the widest  use.  Although cost of these materials is
higher than that of starch, ( approximately 6(/lb for starch, 8-18^/lb
for modified starches,  31^/lb for PVA, and 35^/lb for CMC,  all in  the
unformulated state) ,  they have certain advantages in performance,
particularly with the  synthetics and cotton-synthetic blends, which tend
to offset this cost differential.  The use of these compounds,  therefore,
can be expected to increase  in the coming years as the'use of synthetic
fibers  increases.

Besides  giving increased operating efficiencies, the synthetic  warp sizes,
having a low BOD-5,  have been promoted also as a means of reducing the
pollution potential of  desizing wastes.    The  chemical oxygen demand
( COD)  of  CMC is about as high as  that of starch, however, and the COD
of PVA is higher. Furthermore, results already obtained in this labora-
tory as well as in others,  indicate that  adaptation of bacteria to carboxy-
methyl cellulose  ( 9)  and probably to polyvinyl alcohol ( 11) as  well, does
occur over a prolonged period of time.

Research to decrease the waste load from the desizing of fabrics, there-
fore, may  be concerned with developing more effective and less expensive
treatment methods or with developing processes for recovering and reusing
the desizing products.  The latter alternative appears  to be the  more
desirable whenever it is possible and, indeed,  to represent almost  the
ultimate in pollution control.

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Recovery Methods

The contemplated methods of recovering desizing products were precipitation,
evaporation, and combinations of the two.  Emphasis was placed on precipita-
tion methods which do not require evaporation or other concentrating proce-
dures because,  for economic reasons, the process should be as simple as
possible.

Two general methods may be considered for precipitating warp sizes from
desizing wastes. In one method,  the warp size is chosen, or modified
chemically before application, so that it can be readily precipitated from
dilute solution by a suitable precipitating agent.  In the other method, the
desizing wastes are treated in a manner to modify the warp size so that it
may be  readily precipitated.

The scheme for recovering carboxymethyl cellulose ( CMC)  is an example
of the first method,  which appears also to offer a good way for recovering
polyvinyl alcohol ( PVA) .

The second method has provided the approach taken in attempts to develop
a method for removal of conventional warp-size-grade PVA  from desizing
wastes because,  without chemical modification, this  PVA does not possess
reactive sites which will  permit it to be  precipitated  from dilute solution
by a simple precipitating reaction.  For the same reason, this approach
was taken in attempts to develop a method for removal of the desizing
products from starch-desizing wastes.

Scope and Purpose of Project

The scope and purpose of the project are defined by the objectives which
were

( a)  to develop processes for the recovery of desizing wastes	from
fabrics  sized with carboxymethyl cellulose ( CMC) ,  polyvinyl alcohol
( PVA) , and starch	in forms  suitable for final disposal;

( b)  to develop processes for the recovery of desizing wastes in a reuse-
able form	with the recognition that reuse,  as a size, of the desizing
products from starch is not possible, since starch is  degraded during
desizing;

( c)  to obtain more complete data on the biodegradation of the synthetic
warp sizes,  CMC and PVA,  thus  gaining information on the fate  of these
materials in biological treatment systems and in streams.

The experiments carried out to attain these objectives were  limited to
the laboratories  and pilot plant of the Department of Textile  Chemistry,
North Carolina State  University.

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                           SECTION IV

                      STUDIES AND DISCUSSION


Recovery and Reuse of Carboxymethyl Cellulose ( CMC)


The literature states that sodium carboxymethyl cellulose ( CMC) may be
precipitated as an insoluble salt of aluminum,  copper,  lead, uranium or
zirconium ( 6) .  Early work on this project established that an almost quan-
titative recovery of warp-size-grade CMC can be obtained by precipitation
from  a 0.1$ solution with aluminum sulfate ( filter alum)  .  The recovered
material, which retained a small amount of aluminum, appeared  to be suita-
ble for solid disposal  after dewatering.  On the other hand, the CMC,
precipitated with alum,  dissolved in dilute sodium hydroxide and  was found
suitable  for further use as a sizing agent for cotton yarn.  Performance of
the recovered CMC on the Callaway slasher, a laboratory sizing  machine,
was satisfactory and the results obtained with the sized yarns  on  a warp
shed tester,  which simulates loom performance, were comparable  to
those obtained with yarns sized with new  CMC.

Chemical equations for  the conversion of CMC ( warp-size-grade)  to the
water-insoluble aluminum carboxymethyl cellulose and for the reaction of
the latter with sodium hydroxide to give  a solution of CMC again  are shown
in Figure 1.

Data on precipitation  of CMC from 0.1$ solution with filter alum  are shown
in Table 1.  A ratio of alum to CMC of 0. 71 is  enough  to form  the aluminum
salt of CMC but a larger ratio is necessary to give rapid coagulation and
precipitation and toforma clear supernatant.  The leveling of recovery at
96$ of the original weight occurs because commercial, warp-size-grade
CMC  contains about 4$  sodium chloride,  a by-product in its manufacture,
which is not precipitated by alum.  The increase in total solids in the super-
natant with increasing alum-CMC ratios reflects the increasing amounts of
excess alum which remain  in solution.

A series of cycles of  sizing, desizing, and size recovery was  carried out,
starting  with fresh,  commercial, warp-size-grade CMC and,  in  subsequent
operations, continuing with only the material recovered from  the previous
step.   The sizing trials were carried out on a  blended yarn of cotton and
polyester ( 65:35) with an add-on of size of approximately ten percent of
yarn weight.  Wax, ten percent based  on size, was added to the initial size
bath only; apparently  it is recovered along with the CMC upon precipitation
with alum.  The  scale of these  operations is shown in Table 2. This table
shows also the disproportionately high attrition, arising  from mechanical
losseSj which occurs  in working with relatively small amounts of materials.
The preceding table shows  that these losses  did not occur because the pre-
cipitation and recovery of CMC was incomplete. Such losses of course,

                                   7

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     C6H702(OH) 2.3  (OCH2COONa)0o7 j-n   +  ~^  A12 ( SO4) 3
-f-  C6H?02 ( OH) 2. 3  ( O CH2COO   ) o. 7 ^n   +   Y^~  Na2SO
     C6H702(OH)2-3(OCH2COO^)0.7  ^
r
     C6H702 ( OH) 2. 3 ( O CH2C001Na) 0. 7   "   +  -L  Al ( OH) 3
 Figure 1.  Chemical Equations for ( a) Precipitation of CMC with
 Filter Alum and ( b)  Solution of the Precipitate with Sodium Hydroxide
                              8

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Table 1:  Recovery of CMC by Precipitation with Filter Alurn
               ( from 0.1$ solution of CMC)
Ratio by weight Precipitate
Alum/CMC Recovered (%)
0.50 81
0.75 95
1.00 96
1.25 95
1.50 96
Z.OO 96
Supernatant
Total Solids Appearance
0.051 cloudy
0-065 slightly cloudy
0-085 clear
0.099 clear
Q.127 clear
!
Q. 166 clear j

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  Table 2:  Sizing with  CMC -  New and Recovered
    ( Yarn: Cotton-polyester  ( 65:35)  blend)
Run No.
Reuse No.
Sizing soln prepared ( gal. )

Concn.  of sizing soln ( wt %)

pH of sizing soln

Warp sized ( yd)

Solids in desizing
     liquor ( wt < )
        10
 7. 3
                 0.4
  5-9    8-9   8-9  8-9   13
i.o   7.5  7.3   3.0
6000   3600 1800  600   60
 1.10   1..05  1.05 0 .97

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would not be nearly as  large proportionately in a. large,  plant operation.

After four cycles,  the performance of the recovered CMC on the Callaway
slasher was still satisfactory and the results obtained with the sized yarns
on a warp-shed tester were equivalent to those obtained with yarns sized
with new CMC (See Table 3) .  On the fifth  cycle, however,  the results on
the warp-shed tester were  slightly poorer in that the percent of shed was
higher, the clinging was greater, and there were more stops.  The poorer
results might be due to an accumulation of impurities in the recovered CMC
or they might be due to the method of application which was less  easily
controlled because of the small amount of recovered CMC remaining at
this point.

The properties  of the size at the several stages of recovery are shown in
Table 4.  In Runs 2 and 3,  the CMC recovered from the previous run as a
swollen floe was dried  in an oven at 105C and ground to a powder before
dissolving for reuse; in Runs  4 and 59 the swollen floe was dissolved directly,
eliminating the  time  and expense of two unnecessary steps.  The continuous
diminution in amount of recovered size  because of mechanical losses was
remarked on above.  The decrease in CMC  content of the recovered  mater-
ial  and the increase in  residues  remaining at 600C  are undoubtedly due to a
build-up of impurities.   The high value for residues obtained for the  new
CMC is probably due largely to the presence of sodium chloride which is
formed as a by-product in the  manufacture of CMC.   The aluminum con-
tent of the recovered material is apparently leveling off at about 4$,  a
value which does not appear excessive since the theoretical aluminum
content of aluminum  carboxyrnethyl cellulose is 3.0$.

The steady decrease in the total solids and the CMC content of the  super-
natant from the recovery of size ( see Table 5)  occurred undoubtedly
because a larger amount  of alum was added in the latter precipitations.
The increase was made when it was realized that the rapid precipitation
and settling, obtained with  larger amounts of alum,  would be required
for a practical plant  operation; the slight increase in the amount of mater-
ial  recovered is of secondary importance.  The  increase in the aluminum
content of the supernatant from the latter recoveries also reflects  this
change.

The brown color of the  recovered CMC showed that some of the natural
impurities of the cotton component of the yarn, and probably the  spinning
oil used on the polyester component as well,  are retained by the  CMC
during recovery, while the  yellow or tan color of the liquor remaining indi-
cates that some of these materials remain in solution.  The performance
tests  mentioned above,  however,  indicate that these  materials have no
deleterious effects  during four cycles o operations--and perhaps,  longer--
and the appearance of the yarns after desizing indicates  that none is retained
by the yarns.

                                  11

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Table 3:  Results from Warp Shed Tester on Yarns Sized
         with New and Recovered CMC
 Run No.
Reuse No.
Size add-on ( wt$)
Shed ( wt$)
Fiber in shed ( wt$ )
Stops
Clinging ratio ( $)
Warp tested ( yd)
1 2
1
8.7 10.6
3.1 2.7
40 55
0 0
50 25
20 20
3 4
2 3
9.0 10.7
2.7 2.7
50 30
1 1
50 25
20 20
5
4
13. 5
3. 3
50
2
50+
20

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Table 4:     Date on CMC Size Recovered by Precipitation
Run No.
Reuse No.
Form when dissolved
Dry weight ( Ib)
CMC content (%)
Aluminum content ( % }
Residue at 600C (%)
1 2
1
dry dry
powder powder
5.4
92
0 3.3
33 10.8
3
2
dry
powder
3.5
84
4.3
15.0
4
3
swollen
floe
1.5
82
4.0
16.0
5
4
swollen
floe
0.25
72
4.3
22.9

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Table 5:  Data on Supernatant from Precipitation
                 of CMC Size
Run No.
Reuse No.
Solids ( wt #)
CMC ( wt %)
Aluminum
content ( pprrv)
PH
1 2 3
1 2
0.6 0.6 0.5
0.04 0.03 0.006
225 375 400
4.0 3.9 3.7
4
3
0.4
0.003
400
3.8

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The accumulation of impurities can be expected to reach harmful proportions
eventually,  however, and some of the recovered size will have to be discarded
as a solid waste and replaced with fresh CMC.  This exchange most probably
should be made gradually, beginning with the first recovery,  to an extent
which permits  attainment of steady-state conditions.

Material costs in the recovery of CMC from desizing wastes by precipitation
with filter alum are favorable.  The current prices  of CMC is approximately
35
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Recovery of Polyvinyl Alcohol ( PVA ) from Desizing Wastes

The work with polyvinyl alcohol ( PVA) has not progressed as far as that
with CMC.  An attractive procedure was not found for precipitating and
recovering the conventional warp-size-grade  PVA from desizing wastes,
although a number of materials that will insolubilize PVA are reported
in the literature ( I, E, 10)  .  These materials are classified below accord-
ing to the effect produced on PVA; there is some overlapping in  the classi-
fication, however.

Precipitants.  Polyvinyl alcohol is insoluble in solutions of many salts and
can be precipitated from solution by addition of a salt such as sodium  sul-
fate or  sodium carbonate.  Desizing wastes are so dilute, however, that
the amount of salt required would be impractical and would create a
pollution problem itself.

Insolubilizers.  The water resistance of films and coatings of PVA can be
increased by incorporating any of a number of insolubilizing agents.  These
agents include the amine- or amide-formaldehyde condensates,  such as
dimethylol urea, trimethyol melamine and the various compositions used
to impart durable-press properties to cellulosic fabrics; aldehydes, such
as formaldehyde,  glyoxal,  and hydroxyadipaldehydei polyvalent  metal
salts and complexes, from such metals as aluminum, chromium, copper,
iron,  nickel,  and  titanium; and organic titanates. Insolubilization of PVA
by these materials, however,  is limited to dried films,  usually  with baking,
and cannot be applied to aqueous solutions.

Gelling agents. A number of compounds can cause gellation of solutions of
PVA in water.  These compounds include certain dyes,  such as  Congo Red;
phenolic compounds, such as resorcinol,  catechol,  phloroglucinol, gallic
acid,  salicylamide, and 2,  4 - dihydroxybenzoic acid; and inorganic complex-
ing agents,  such as borax--a particularly effective  gelling agent,  certain
vanadates, and compounds  of trivalent chromium and of tetravalent tita-
nium.   These compounds cause gellation only in PVA solutions in which
the concentration  of PVA is higher than that likely to be encountered in
desizing wastes and, of course,  gellation of the entire solution provides
no means of separating the PVA.

Consideration of the literature cited above,  together with qualitative experi-
ments with borax, phenolic compounds, and aldehydes,  led to the conclu-
sion that precipitating and recovering conventional warp-size-grade PVA
from desizing wastes, without a prior concentrating step, would be difficult
if not impossible.

                                    16

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A modified PVA has been prepared which is precipitated from dilute solution
by filter alum.  This material was  prepared by emulsion copolymerization of
vinyl acetate with a relatively small amount of acrylic acid and hydrolysis
of the resulting copolymer.  The chemical transformations are shown in
Figure  2.  Although this material has not been prepared in sufficient quan-
tity for conclusive evaluation as a warp size,  some preliminary results have
been  obtained on  the Callaway slasher and the warp-shed tester.  Slashing
was  routine but the results  on the warp-shed tester were poor in comparison
with those obtained with commercial warp-size-grade PVA.  That this mater-
ial performed at  all,  however,  is an indication that, with proper adjustment
of composition and molecular weight, it should be a satisfactory warp size.

Similar considerations apply to another modification of PVA which was pre-
pared recently and found to be precipitated from dilute solution by lowering
the pH to about 3.  Material costs in a recovery process based on  acidifica-
tion should be low ( sulfuric acid: about 1.5/lb) .  This modified PVA was
prepared by the copolymerization in emulsion of vinyl acetate,  acrylic acid
and dibutyl maleate,  followed by  partial hydrolysis of the resulting copolymer.
These transformations are  shown in Figure 2.

Results from the warp-shed tester  on cotton-polyester ( 65:35)  yarns sized
with these copolymers are  shown in Table 6.

Removal of Desizing  Products of Starch from Desizing Wastes

Starch and the  desizing products  from starch-sized fabrics are biodegrada-
ble and are largely removed from textile-plant wastes by biological treat-
ment systems.  Biodegradation,  of course, results in the formation of a
sludge which must be  disposed of by other means.  Exploratory attempts
were made in the present work to find a procedure for removing starch-
desizing products by chemical precipitation.

Examination by thin-layer chromatography ( TLC) of enzymatic desizing
wastes, from starch-sized  fabrics,  obtained from a nearby textile  plant,
showed that none of the low-molecular-weight sugars--dext rose, maltose,
maltotriose,  etc.--were present.  The  starch was degraded, of course,
but the  products were still  polymers of  relatively high molecular weight.
Further enzymatic treatment of the desizing wastes in the laboratory
produced the sugars.  Similar results were obtained with a desizing
waste from another plant which employed a caustic desizing of  starch-
sized fabrics.  If these textile plants are  typical,  an error has been made
by writers who have assumed that starch  desizing wastes consist mostly
of dextrose and other  sugars of relatively low molecular weight.

The  above observation suggested that a  means might be found for precipi-
tating and recovering  starch-desizing wastes as polymers rather than as
                                   17

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                -CH,- CH  -*-.-
                      COOH.
                         r
        --CH2 - CH		-ICH, - CH.	
              OH
                     COONa
                                      "b
                                           .CH  - CH-
                                                   i
                                            CO    CO
                                            p     o
Figure  2.  Chemical Transformations in the Preparation of Polyvinyl
                            Alcohol Copolymers
                                18

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Table 6:  Results from Warp-Shed Tester on Yarn Sized with PVA and
         PVA Copolymers
a.  Vinol 540  polyvinyl alcohol ( PVA)

b.  Vinol 125 polyvinyl alcohol ( PVA)

c.  Vinyl alcohol/acrylic acid copolymer

d.  Vinyl alcohol/acrylic acid/dibutyl maleate copolymer
Sample
Size add-on ( wt $)
Shed ( wt %)
Fiber in shed ( wt $)
Stops
Clinging ratio ( $)
Warp tested ( yd)
Concn. of size ( wt $)
la
1Z. 5
0.7
4.6
0
25
20
9.8
2*
11.7
0.8
50
0
25
20
9.8
3b
8. 3
0.6
75
0
25
20
8.0
4b
8.1
0.8
75
0
25
20
8.0
5
11.5
4.1
67
5
75
12
10.0
S
8.8
5.6
66
2
75
20
7.7
                                   19

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sugar derivatives.  The  oxidation of starch to give a material containing
aldehyde, ketone and carboxylic-acid functions is recorded in numerous
publications in the literature and,  indeed, "oxidized starch" is  a commer-
cial product widely used in the paper industry (12 ).   Oxidation experiments
were carried out on starch solutions ( 1 $) to determine if carboxyl groups
might be introduced into the starch molecule and permit precipitation with
polyvalent metal salts in the  same manner as CMC.  The oxidizing agents
were sodium hypochlorites a common textile bleach as well as the oxidant
used to prepare commercial  "oxidized starch"; sodium chlorite, another
common textile bleach;  and sodium bromite, a starch-desizing  agent. None
of the oxidations performed so far, however,  gave  a product which was
precipitated with filter alum  or ferric chloride.  Solutions ( 1 $) of three
"oxidized starches" ( Stayco  G, Stayco M and Stayco S--different viscosity
grade   of oxidized corn  starch from A.  E. Staley Manufacturing Co. ) were
treated with alum but none gave a  significant amount of precipitate.

Biodegradation of Carboxymethyl Cellulose  ( CMC)

In the first exploratory  experiment on the biodegradation of CMC,  a labor-
atory aeration  chamber  ( small-scale activated-sludge unit) was  arranged
for the  continuous feed of  a dilute  ( 0.03^) solution of CMC containing the
necessary mineral nutrients.  Bacterial seed was obtained from a munici-
pal sewer.  The CMC solution ( 5  liters)  was passed through the  aeration
chamber ( 2-liter capacity)  and recirculated for four  weeks.   At the end
of this time, a 20$ reduction of the CMC content, measured spectrophoto-
metrically ( see Appendix A) , of the circulating  solution was noted.   Recir-
culation was discontinued  at this point and the entire mass was  transferred
to a five-liter flask for  aeration in a static condition,  a simpler procedure
which seemed likely to accomplish the same result as aeration  with recir-
culation.  Reduction of CMC  content advanced to  about 35$ and  then leveled
off.  No further reduction occurred even over a prolonged period.

In another experiment,  after a suitable  sludge ( MLSS = 1500 rng/l)  had
been developed from sewage  bacteria and a  synthetic sewage feed ( see  Table
 7 ) , the organic materials ( dextrose,  starch, yeast extract)  in the feed
were replaced  gradually in increments of 10$ over a period of 12 weeks  with
an equivalent amount of  CMC ( based on COD) .   The detention time in the
aeration chamber was approximately 14 hours.  A trend toward reduction
of the CMC concentration,  measured spectrophotometrically ( see Appendix
A) , between the influent and effluent streams was noted after several weeks
and this reduction increased  with increasing substitution of the  organic
matter  by  CMC. At 100$  substitution it was 15$  in the beginning and it
increased to about 65$ after  eight weeks.  Reductions at this level continued
for 10 weeks and then began to decline.  The mixed-liquor suspended solids
( MLSS) began to decline  at the same time, indicating that the system was
experiencing a nutritional deficiency.   This result was not unexpected since

                                   20

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Table 7.  Synthetic Sewage Feed
Ingredients
Yeast extract
Dextrose
Starch
NH4C1
CaCl2 ' 2H2O
FeSO4  7H2O
MnSO4  H2O
MgSO4  7H2O
K2HPO4
Tap-water
COD
Amount ( mg. )
158
80
80
63
10
10
10
300
40. 3
to 1 liter
300 mg/1
                   21

-------
the feed for some time had contained no proteins or vitamins--CMC was
the only organic material in the feed.   The results of this experiment
are shown in Table 8 and in Figures 3 and 4 .

For another experiment, a sample of  sludge was obtained from a small,
experimental aerated lagoon used by Dan River, Inc. , Danville, Virginia,
in treating a portion  of its plant effluents.  This plant uses  CMC almost
exclusively as a warp size and its wastes  had been discharged to the lagoon
for over two years.   The sludge  sample (  MLSS = 2000  mg/l)  was used in
a laboratory activated-sludge unit which was fed continuously with a CMC
solution ( 0.03$)  containing essential mineral  nutrients ( see  Table 7 )
A reduction in CMC concentration, measured spectrophotometrically
( see Appendix A) , between influent and effluent streams was  noted
almost immediately.   This  reduction increased and reached the 70-805?
level after five weeks and remained in this range for about  10 weeks.
At the end of this time  it declined precipitously,  along with the MLSS,
indicating that the system was reacting to a nutritional deficiency.  These
results are shown in  Table  9 and in Figures 5 and  6 .

Biodegradation of Polyvinyl Alcohol ( PVA)

After a suitable sludge ( MLSS = 1800  mg/l)  had been developed in a
laboratory activated-sludge unit from sewage bacteria and  a synthetic
sewage feed ( see Table 7  )  the organic  materials ( dextrose, starch,
yeast extract)  in the feed were replaced gradually in increments of 10$
over a period of 18 weeks with an equivalent amount of PVA.   The deten-
tion time  in the aeration chamber was  approximately two days.  A trend
toward a reduction of the PVA content,  measured spectrophotometrically
( see Appendix A) , between the  influent and effluent streams was noted
alter four weeks  ( 40$ substitution of PVA) and this reduction continued
to increase with increasing time and substitution of PVA.   It reached
approximately 60$ after 16 weeks  ( 90$  substitution of PVA)>  remained
in the 60-65$ range  for an additional 17 weeks, and then began to decline--
apparently as a result  of nutritional deficiency.  The results of this experi-
ment are  shown in Table 10 and in Figures 7 and 8 .
                                   21

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Table 8:  Removal of CMC with Activated Sludge Developed in Laboratory
Date
8/14/70
9/11/70
9/18/70
9/23/70
9/30/70
10/7/70
10/14/70
11/11/70
11/18/70
11/25/70
12/2/70
12/9/70
12/16/70
12/30/70
1/7/71
1/15/71
1/20/71
2/5/71
3/11/71
5/14/71
5/17/71
Time
( weeks )
8
12
13
13
15
16
17
21
22
23
24
25
26
28
29
30
31
33
38
47
47
Substitu-
tion of
CMC (#)
70
80
90
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
CMC Concentration
Influent
(*)
0.0180
0.0210
0.0230
0.0250
0.0295
0.0255
0.0290
0.0280
0.0300
0.0340
0.0330
0.0320
0.0305
0.0280
0.0315
0.0330
0.0310
0.0315
0.0330
0.0295
0.0290
Effluent
(*)
0.0160
0.0190
0.0210
0.0215
0.0220
0.0210
0.0240
0.0205
0.0110
0.0130
0.0170
0.0120
0.0150
0.0050
0.0085
0.0130
0.0110
0.0200
0.0240
0.0255
0.0240
Reduction
(*)
11
10
9
14
25
18
17
29
63
62
48
63
52
82
73
61
65
34
27
14
17
                                   23

-------
IV
o

o

UL
O

Z
O
I-

o:

z
LU
O
Z
o
o
         O.O5
         O.O4
         O.O3
         0.02
         O.OI
         O.OO
                       Figure 3   Treatment of CMC with Activated Sludge

                                  Developed in Laboratory
                                                         INFLUENT
                                                         EFFLUENT
                     10
                              2O
3O
4O
50
                                        TIME  (WEEKS)

-------
             IOO
                          Figure 4 :  Removal of CMC with Activated Sludge

                                     Developed in Laboratory
ro
U

5
o

U.
O
        O
        
        LU
        o:
              8O
              60
              4O
      20
                O
                        IO
                                20
30
40
50
                                             TIME   (WEEKS)

-------
Table9:  Removal of CMC with Activated Sludge from Dan River
         Treatment Plant
j

-------
    O.O5

O

2
O  O.O4 -
LL
O
o:
h
    O.O3
    O.O2
UJ  O.OI
o
z

8  o.oo
                  Figure 5 ;  Treatment of CMC with Activated Sludge

                            from Dan River Treatment Plant
INFLUENT
      EFFLUENT
                              IO
                 2O
                                 TIME  (WEEKS)

-------
                        Figure  6:  Removal of CMC with Activated Sludge

                                  from Dan River Treatment Plant
oo
      o
      s
      o

      LL
      O
      O
      LU
      o:
         IOO
          so
BO
          4O
          2.O
            O
                                    10                    20


                                       TIME   (WEEKS)

-------
TablelO:  Removal of PVA with Activated Sludge Developed in Laboratory
Date
9/25/70
10/23/70
Time
( weeks )
0
4
12/10/70 I 11
12/17/70
1/6/71
1/21/71
12
15
17
2/19/71 21
5/14/71 33
_ , . R PVA Concentration j
tion of PVA j; Influent
1
40 * 0.0125
70 J 0.020
80  0.026
80 I 0.026
t'
Effluent i Reduction
b
/ ^j \ . / (jj \
i
6.0115 | 8
0.010 ( 50
\
0.006 | 77
,1
0.014 \ 46
s
90 1 0.026 j 0.009 i 65
100 \ 0.024 ! 0.010 ! 58
j  A
100 ! 0.026
r
5/17/71 33 H 100 I 0.026
0.010 1 62
)
0.012 i 54
j
1 1 i 1 : i
                                  29

-------
    O.O5 -
    O.O4 -
                     Figure  7:  Treatment of PVA with Activated Sludge

                               Developed in Laboratory
u.
o
O
o:
o
z

o
    O.O3
    0.01
O.OO
                                                        INFLUENT
                                                      EFFLUENT
                          10
                                           20
30
                                  TIME   (WEEKS)

-------
     IOO
                     Figure  8:  Removal of PVA with Activated Sludge
                                Developed in Laboratory
U_
O
O
S
UJ
o:
      SO
6O
      40
2O
        O
                          IO
                                           2O
3O
                                    TIME   (WEEKS)

-------
                                SECTION V

                           ACKNOWLEDGEMENT
This report was prepared by Carl  E.  Bryan, Project Director, with the
assistance of the other people engaged in the work on the project.

The major part of the bench-scale laboratory studies, including the
analytical work, was carried out by Peggy S.  Harrison.  The warp-sizing
experiments, together with the  trials on the warp-shed tester, were  per-
formed by  Charles D. Livengood and Gene G. Floyd,  The copolymers of
vinyl acetate and vinyl alcohol were prepared by Samia G.  Saad.

Plant waste samples were obtained through the courtesy of Burlington
Industries, Inc., Cone Mills Corporation,  and Dan River,  Inc.

The interest and advice of Charles Smallwood, Jr. , Department of
Civil Engineering,  throughout the course o this investigation is acknow-
ledged with pleasure.  Helpful discussions regarding the biodegradation
experiments  were held with  him and with William S, Galler and Frank J,
Humenik, also of the Department of Civil  Engineering.

Early phases of the work, including the preparation of the research
proposal, were supported by the Water Resources Research Institute
of the University of North Carolina, David H. Howells, Director.  This
support was  essential and is hereby acknowledged.

The support  of the  major  part of the program by the Federal Water
Pollution Control Administration, later the Environmental Protection
Agency,  and the help provided by Harold J. Snyder, Jr. , the Grant
Project Officer, is gratefully acknowledged.
                                  33

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                                 SECTION VI

                                 REFERENCES
 1.  Air Reduction Co. , Inc. , Technical Bulletin, "Airco Vinol Polyvinyl
       Alcohol", 1965.

 2.  E. I. DuPont de Nemours and Co., Inc., Technical Bulletins, "Elvanol
       Polyvinyl Alcohol", 1968,  and "Increasing Water Resistance of
       Elvanol Polyvinyl Alcohol", 1969.

 3.  Eyler,  R.  W. ,  and R,  T. Hall,  "Determination of CMC in Paper",
       Paper Trade Journal, 125  ( 15) , 59-62 ( 1947) .

 4.  FWPCA Methods for Chemical Analysis  of Water and Wastes, U. S.
       Department of the Interior, November, 1969.

 5.  Finley, Joseph  H. ,  "Spectrophotometric Determination of Polyvinyl
       Alcohol in Paper Coatings", Analytical Chemistry,  33. ( 13) ,  1925-7
       (1961) .

 6.  Hercules, Inc.,  Technical Bulletin, "Analytical Procedures for the
       Assay of CMC and Its Determination in Formulations", 1966.

 7.  Humenik, Frank J. ,  North Carolina State University, private communi-
       cation.

 8.  McKinney, Ross E. , Microbiology for Sanitary Engineers, McGraw-
       Hill Book Co., Inc., New York, 1962.

 9.  Moore, Glenn E. , Virginia State Water Control Board,  private communi-
       cation.

10.  Pritchard, J. G. , Polyvinyl Alcohol -Basic Properties and Uses,
       Gordon and Breach Science Publishers, New York,  1970.

11.  Pullekines,  John J. ,  Air Reduction Co0 , Inc., private  communication.

12.  Roberts, Hugh J. , "Nondegradative Reactions of Starch',1 in  Chemistry
       and Technology of Starch, edited by Roy L. Whistler and Eugene F.
       Paschal, Academic Press, Inc., New York, 1965, Vol.  1, pp.439-93.

13.  Sorenson,  Wayne  R. , and Tod W.  Campbell,  Preparative Methods of Poly-
       mer Chemistry, Interscience Publishers,  Inc. , New York, Second
       Edition,  196~87~~

                                   35

-------
14.  Stahlj  Egon, and U. Kaltenbach. "Sugars and Derivatives", in Thin-
      Layer Chromatography -- A Laboratory Handbook, edited by Egon
      Stahl, Academic Press, Inc.,  New York,  1965,  pp. 461-9.

15,  Standard Methods for the Examination of Water and Wastewater,
      American Public Health Association,  Inc., New York, Twelfth
      Edition,  1965.
                                  36

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                             SECTION VII
                      PUBLICATIONS AND PATENTS
A paper based on a portion of this work was presented before the 20th
Southern Water Resources and Pollution Control  Conference in Chapel
Hill, North Carolina on April 2, 1971 and before a meeting of the
Northern Piedmont Section of the American Association of Textile
Chemists  and Colorists in Durham,, North  Carolina on April 17, 1971.
It is expected that this paper and others  resulting from this work will
be submitted for publication.
                                   37

-------
SECTION VIII




APPENDICES
    39

-------
                   APPENDIX A -  LABORATORY PROCEDURES

Materials

Yarn:  A 40/1 cotton-polyester ( 65:35) yarn was used in the sizing and
desizing experiments.

Sodium, carboxymethyl  cellulose ( CMC) :  A warp-size-grade CMC, labelled
cellulose Gum 7L, was obtained from Hercules,  Inc.

Polyvinyl alcohol ( PVA) :  Warp-size-grade PVA was obtained from E.  I.
duPont de Numours and Co., Inc. ( Elvanol 51-05) and Air Reduction Co.,
Inc.  (  Vinol 125 and Vinol 540) .

Starch:  Douglas pearl corn starch from Penick and Ford,  Ltd.

Aluminum sulfate ( filter alum) :  Fisher Scientific Co. ,  Technical, No. A-611.

Ferric chloride:  Baker and Adams on, Reagent A. C. S. ,  No. 1736.
Other  chemicals:  The  reagents used in the analytical work were of the
highest quality available commercially.

Methods
Sizing,  Desizing,  and Size^ Recovery

Sizing:  The  sizing trials were carried out on a Callaway slasher, a labora-
tory sizing machine, and 252 ends were  sized in a single pass.
Desizing: The sized yarns were desized in batches in an autoclave using
hot ( 200-210F) water.  Each batch (  about 1700 g) of yarn was treated
for 30 minutes with three consecutive  portions ( each, about 15 liters)  of
water and, to keep the volume of desizing liquor small,  the third portion
of water used with each batch of yarn was the first portion used with the
next batch.   The total solids of the desizing liquors obtained in this way
were  approximately 1% ( 10, 000 mg/1)  .
Precipitation of size: A 10$ ( by weight) solution of filter alum was used
in precipitating CMC from desizing wastes, although the concentration  of
precipitant is not  a critical factor.  Enough alum was added to effect com-
plete  precipitation of the CMC and the amount added was from 75$ to 100$
of the weight of CMC recovered  (See Table 1) .  The larger ratios of alum
to CMC  resulted in more rapid coagulation and precipitation with clearer
supernatants.
Recovery of  precipitated size:  The CMC-alum  complex settled as a highly
swollen, fluffy sludge.  Dewatering was  accomplished by decanting the
supernatant, collecting the swollen sludge  on a  cloth filter, and then further
removing excess water  by centrifuging.  The amount of  water  in the sludge
was reduced to 90$ or less to permit the preparation of a new sizing solu-
tion of the proper concentration.

                                   41

-------
 Solution of recovered size:  The recovered CMC-alum complex was dissolved
 in sodium hydroxide for reuse as a warp size.  Good agitation was found to
 be essential for this operation and a laboratory homogenizer ( Eppenbach) was
 used in the  present work.  The sodium hydroxide  ( 10 <)  was added dropwise
 to the stirred sludge and, within a few minutes, a smooth,  somewhat cloudy
 solution with a pH  of about 8, was  obtained.  Adjustment of the concentration
 was made by the addition  of the proper amount of water.

 Preparation jgfjolyvinyl  alcohol copolymers

 Polymerization:  Copolymers of vinyl acetate with other monomers were
 prepared by emulsion polymerization.  The reaction was carried out in a
 multinecked, Pyrex reaction kettle, which was fitted with a mechanical
 stirrer, a thermometer, a dropping funnel, a reflux condenser and a tube
 for introducing nitrogen above the  reaction mixture.  The procedure  used
 in the present work is described in Preparative Methods of Polymer
 Chemistry  (13) .
 Hydrolysis:   The  vinyl acetate copolymers, prepared as described above,
 were hydrolyzed to the corresponding vinyl alcohol copolymers in methanol
 solution using  sodium methoxide as the catalyst.  The reaction was conducted
 in a multinecked reaction flask which was equipped with a mechanical stirrer,
 a reflux condenser and a dropping  funnel.  The procedure is described in
 Preparative Methods of Polymer Chemistry (13) .

 Oxidation of starch

 Oxidation experiments on Douglas pearl corn starch were carried out in
 Pyrex reaction vessels equipped with a stirrer,  thermometer, and a  drop-
 ping funnel for addition of reagents  as needed.  Oxidations with sodium
 hypochlorite were  performed at room temperature using up to 20$( by
 wt, solids basis)   sodium hypochlorites based on starch; oxidations with
 sodium bromite were performed also at room temperature, with up to 5$
 ( by wt)  "Preptone" sodium bromite desizing  solution, based on starch;
 oxidations with sodium chlorite were at 80C,  with up to 10$( by wt)
'Textone" sodium chlorite bleach,  based on starch.  Reactions  were
 allowed to proceed over a period of 4-5 hours or longer, and thinning
 of the starch occurred in every case, but a significant amount of precipi-
 tate was not formed in any case upon addition  of alum.
                                    42

-------
Analyses

Carboxymethyl  cellulose ( CMC) , in desizing liquors and in the effluents
from laboratory activated-sludge  units, was determined by the 2, 7-dihyr
droxynaphthalene colorimetric method ( 3, 6) .  According to this method,
the carboxymethyl groups in CMC are converted to glycolic acid by boiling
the sample in 50% sulfuric acid.  The mixture is then treated with the
2, 7-dihydroxynaphthalene reagent, which reacts with the glycolic  acid
to give a purple color.  The intensity of this color is measured at its
absorption maximum of 540 m^.  The principal compounds that interfere are
formaldehyde and substances which yield  formaldehyde under the condi-
tions of the analysis.

Polyvinyl alcohol ( PVA) analysis,  in the effluents from laboratory
activated-sludge units, was based on the green color produced by the
reaction of PVA with iodine in the presence of boric acid ( 5 ) .   The
intensity of the  color is measured at the absorption maximum of 690rry.
The principal interfering sustance likely to be encountered in work of
the present nature is starch and its effect can be eliminated by a pre-
treatment involving  acid hydrolysis.

Aluminum, in CMC-alum, complexes and in supernatants, was determined
by atomic absorption spectroscopy in accordance with the procedure recom-
mended in the FWPCA  manual for chemical analysis  ( 4 ) .

Total solids  were determined gravimetrically by the procedure  outlined
in the FWPCA manual for chemical analysis  ( 4 ) .

Residues at 600C were determined gravimetrically by the procedure given
in Standard Methods (15) .

Desizing products from starch-sized fabrics were examined by thin-layer
chromatography ( TLC) .  The adsorbent  was Kieselguhr G  ( Merck)
impregnated with 0.1 M monosodium phosphate and spread onto glass
plates;  the solvent was a mixture of n-butanol, n-propanol,  acetone,
ethyl acetate, ammonium hydroxide  (28$ NH3 by wt)  and water
( 7:6:7:4:2:4} .  The chromatograms were developed by spraying the
plates with a solution of potassium dichromate in sulfur ic acid and then
drying them in an oven.  The technique of TLC has been described in
a number of monographs; one, edited by Stahl (14) ,  contains a chapter
on Sugars and Derivatives which describes analyses of the type carried
out in this  project.
                                   43

-------
Biodegradation Experiments

The biodegradation trials on CMC and PVA were carried out in labora-
tory activated-sludge units,  of which  two types were used.  A picture of
one such unit, used in the present work in  building up  and acclimatizing
sludges to CMC and PVA, is shown in Microbiology for Sanitary Engineers
by McKinney ( 8 ) .  It is a rectanguloid chamber,  7"  ( width)  x 11" ( height)
x 13"  ( length) ,  constructed of polymethyl  methacrylate,  and divided verti-
cally into four equal compartments, each 7" x 11" x  3", so that four experi-
ments can be  conducted simultaneously  under the same conditions.  The
capacity of each compartment is two liters.  Provision is made for contin-
uous addition  of influent and overflow of effluent, sludge withdrawal, aera-
tion and stirring.  A diagramatic sketch of the other unit which was
constructed of Pyrex glass  is shown in Figure  9.  It was used in the trial
of CMC biodegradation with a sludge obtained from the waste-treatment
plant of a textile mill which had been  using CMC as the predominant
warp size  for several years.  The capacity of the aeration chamber is
four liters.  This unit is designed also for continuous  operation.
                                   44

-------
                                       AIR  LIFT
                                       SLUDGE RETURN
                    MECHANICAL
                    STIRRER
INFLUENT
                                              EFFLUENT
                       \
                        SLUDGE
                        REMOVAL
Figure  9:  Laboratory Activated-Sludge Unit, Consisting
            of Aeration Chamber  ( A) and Separation
            Basin ( B)  ( approximate scale: two inches=
            one foot)
                       45

-------
                  APPENDIX B - RELATED LITERATURE
In the Department of Textile Chemistry of the School of Textiles of
North Carolina State University,  an exploratory study was made of the
possibility of recovering and reusing synthetic, or partially synthetic,
warp sizes  ( 2) ,  A large part of this study was a survey of the litera-
ture dealing with textile wastes.  This survey,  which was recently
expanded and updated ( 5) , showed that little work had been done on
the recovery and reuse of textile processing chemicals.   The caustic
soda used in mercerjzation appears to be the outstanding  exception
( 1, 4,  6) .  In the other part of the study at North Carolina State
University, it was found  that a CMC sizing solution could be  reconsti-
tuted, by addition of the required amount of CMC to the dilute desizing
wastes,  to give a formulation which performed satisfactorily as a
warp size during weaving.

More closely related to the work described in this  report are processes
described in three recent patents.  According to one patent ( 3) ,  an
alkali starch phosphate may be used as a warp size for textile yarns;
the size  is easily removed without degradation after weaving and the
de sizing liquor, although quite dilute in the examples given, may be
used to make up a new starch  phosphate,  sizing solution.   On the
other hand, the size may be precipitated from  the desizing liquor
with a divalent cation, such as  calcium,  to leave a waste liquor with
low BOD.  According to the other two patents (7, 8) ,  alkali metal
salts of ethylene-acrylic  acid  copolymers  are suitable  for sizing
textile yarns  and the size is recoverable from  the desizing liquors
by precipitation with acid.  The processes described in these
patents,  however, do not appear to have received industrial appli-
cation.
                                  47

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References Cited

1.  Becknell, D. F.  "Uses of Caustic Soda Recovered from the Merceriza-
   tion Process," M. S. Thesis, Georgia Institute of Technology, 1965,

2.  Berrier,  R. N., and H, Y. Jennings, "Recoverable  Warp Sizes",  Pro-
   ceedings  of the 15th Southern Water Resources  and Pollution Control
   Conference, 81-83 ( 1966) .

3.  Bode, H, E., "Process for  Sizing Textiles and the  Disposition of
   Sizing Wastes Therefrom".,  U. S.  Pat. 3,093,504 ( June 11,  1963).

4.  Jones,  L. D, , "Recovery of Caustic Soda from the  Mercerization
   Process," M. S.  Thesis, Georgia Institute of Technology, 1965,

5.  Livengood, C. D. , "Textile Wastes - A Bibliography," Water Resources
   Research Institute of the University of North Carolina, Report No.  18,
   1969.

6.  Nemerow, N. L., and W. R. Steel,  "Dialysis of  Caustic Textile Wastes",
   Proceedings of the 10th Industrial Waste Conference,  Purdue University
   Engineering Extension Service, No.  89, 74-81  ( 1955) .

7.  Walter,  A. T.,  G. M. Bryant and C. L. Purcell, "Process for Sizing
   and Desizing Textile Fibers," U. S. 3,321,819  ( May  30, 1967) , assign-
   ed to Union Carbide Corporation.

8.  Walter,  A. T.,  G. M, Bryant and C, L. Purcell, "Alkali Metal Salts
   of Ethylene - Acrylic Acid Interpolymers, "  U,  S. 3,472,825 ( October 14,
   1969) >  assigned  to Union Carbide Corporation.
                                 48

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1

5
/loceNs'io/i Number
2

Subject Field &. Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
                Raleigh, North Carolina 27607
     Title
                Water Pollution Reduction through Recovery of Desizing Wastes
JQ Authors)
Carl E.
Bryan
16

21
Project Designation
EPA 12090
EOE 01/72
/Vote
 22
     Citation
 23
Descriptors (Starred First)
       Industrial wastes*,  Pollution abatement*, Textiles*,  Acclimatization*,
       Chemical precipitation
 25
     Identifiers (Starred First)
           Reuse *,  Warp sizes  *,  Carboxymethyl cellulose,  Polyvinyl alcohol,
            Alum
 27
    Abstract
    Processes for precipitating from desizing wastes the synthetic warp sizes,  carboxy-
methyl cellulose  ( CMC)  and polyvinyl alcohol ( PVA) ,  were investigated.  Carboxymethyl
cellulose is precipitated quantitatively by certain multivalent metal salts, such as alumi-
num sulfate and ferric chloride.  Aluminum sulfate is the more suitable for size recovery.
    Cycles of sizing,  desizing and size recovery were performed on cotton-polyester
( 65:35) yarns, starting with commercial CMC, and continuing with only the recovered
material.  After four cycles, the performance of the  recovered CMC on a Callaway
slasher was  satisfactory and results with the sized yarns on a warp-shed tester were
equivalent to results with yarns sized with new  CMC.
    Two copolymers of PVA were prepared, one of which was precipitated from dilute
solution by aluminum sulfate and ferric chloride, the other by acidification.  Preliminary
sizing trials with small samples of materials indicate that these,  or similar,  copolymers
may be effective,  recoverable warp  sizes.
    Evidence was  obtained that acclimatization of sewage bacteria to CMC and PVA occurs
upon prolonged contact in a laboratory activated-sludge unit.
/tbsfracfor
        Carl E.  Bryan
                             Inxtitution
                                   North Carolina State University-
 WR:I02 (REV. JULY 1969)
 WRSIC
                                        SEND TO: YlATER RESOURCES SCIENTIFIC INFORMATION CENTER
                                               U.S. DEPARTMENT OF THE INTERIOR
                                               WASHINGTON. D. C. 20240
                                                                            . GPo: 1969-399-339

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