Development Document for Effluent Limitations Guidelines
 and New Source Performance Standards for the
FLAT GLASS
Segment  of the  Glass
Manufacturing

Point Source  Category
                  JANUARY 1974
       £    U.S. ENVIRONMENTAL PROTECTION AGENCY
\ ^ST/jL T          Washington, D.C. 20460

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                  DEVELOPMENT DOCUMENT

                           for

             EFFLUENT LIMITATIONS GUIDELINES

                           and

            NEW SOURCE PERFORMANCE STANDARDS

                         for the

                   FLAT GLASS SEGMENT

                         of the

       GLASS MANUFACTURING POINT SOURCE  CATEGORY
                    Russell E. Train
                      Administrator

                      Roger Strelow
Acting Assistant  Administrator for Air 6 Water Programs
                         / •» ri
                         (SB/
                       Allen Cywin
        Director,  Effluent Guidelines Division

                    Robert J. Carton
                     Project Officer
                       January 1974

             Effluent  Guidelines Division
           Office of Air and Water Programs
         U.S. Environmental Protection Agency
                Washington, D.C. 20460
 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.O. 20402 - Price $1.66

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                            ABSTRACT
This document presents the findings of an extensive study of  the
flat  glas s  manufacturing  industry  by  Sverdrup  &  P ar eel and'
Associates, Inc. for the Environmental Protection Agency for  the
purpose  of  developing  effluent limitations guidelines. Federal
standards of performance,  and  pretreatment  standards  for  the
industry, to implement Sections 304, 306, and 307 of the "Act."

Effluent  limitations  guidelines  contained herein set forth the
degree of effluent reduction attainable through  the  application
of  the  best  practicable control technology currently available
and the degree  of  effluent  reduction  attainable  through  the
application   of   the  best  available  technology  economically
achievable which must be achieved by existing  point  sources  by
July  1,  1977  and July 1, 1983, respectively.  The Standards of
Performance for new sources contained herein set forth the degree
of effluent reduction which is achievable through the application
of the best available demonstrated control technology, processes,
operating methods, or other alternatives.

The development of  data  and  recommendations  in  the  document
relate  to  the  flat  glass  manufacturing  and automotive glass
fabricating segments of the glass manufacturing industry.   These
two segments are further subdivided into six subcategories on the
basis  of  production  processes and waste water characteristics.
Separate effluent limitations were developed for each subcategory
on the basis of the level of raw waste load as  well  as  on  the
degree of treatment achievable by suggested model systems.  These
systems   include,  coagulation,  sedimentation,  filtration  and
certain in-plant modifications.  Supportive  data  and  rationale
for  development  of the proposed effluent limitations guidelines
and standards of performance are contained in this document.
                                111

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SECTION

   I

  II

 III
  IV

   V
  VI

 VII
VIII
  IX
             CONTENTS                   PAGE

Conclusions                                1

Recommendations                            3

Introduct ion                               5

     Purpose and Authority                 5
     Summary of Methods                    6
     General Description of Industry      15
     Production and Plant Location        18
     General Process Description          22

Industry Categorization                   29

Water Use and Waste Characterization      33

     Auxiliary Wastes                     33
     Sheet Glass Manufacturing            34
     Rolled Glass Manufacturing           36
     Plate Glass Manufacturing            36
     Float Glass Manufacturing            42
     Solid Tempered Automotive Glass      45
       Fabrication
     Windshield Fabrication               51

Selection of Pollutant Parameters         59

Control and Treatment Technology          69

     Sheet and Rolled Glass Manufacturing 69
     Plate Glass Manufacturing            70
     Float Glass Manufacturing            74
     Solid Tempered Automotive Glass      78
       Fabrication
     Windshield Fabrication               83

Cost, Energy, and Non-Water Quality Aspects  91

     Cost and Reduction Benefits          9]
     Energy Requirements                102
     Non-Water Quality Aspects          103

Best Practicable Control Technology     105
 Currently Available

     Introduction                       105
     Effluent Reduction Attainable      1Q5
     Identification of Technology       107
     Rationale for Selection            109

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SECTION

   X
            (CONTENTS CONT'D)
PAGE
  XI

 XII

XIII

 XIV
Best Available Technology Economically   113
 Achievable

     Introduction                        113
     Effluent Reduction Attainable       114
     Identification of Control Technology   115
     Rationale for Selection             117
New Source Performance Standards

Acknowle dgement s

References

Glossary
 119

 131

 123

 125
                                V1

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NUMBER

   1

   2

   3

   4


   5

   6

   7

   8

   9


  10

  11

  12

  13




  14
             FIGURES


Data Retrieval Form

Sample Computer Format

Flat Glass Industry

Location of Manufacturing Plants in
  U.S., 1973

Sheet Glass Manufacturing

Rolled Glass Manufacturing

Plate Glass Manufacturing

Float Glass Manufacturing

Solid Tempered Automotive Glass
  Fabrication

Windshield Fabrication

Wastewater Treatment - Plate Process

Wastewater Treatment - Float Process

Wastewater Treatment -
  Solid Tempered Automotive Glass
  Fabrication

Wastewater Treatment - Windshield
  Fabrication
PAGE

  9

 n

 17

 19


 35

 37

 39

 43

 47


 52

 72

 77

 81



 86

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NUMBER

   1

   2

   3
   5


   6


   7


   8


   9

  10


  11


  12



  13


  14




  15
              TABLES                      PAGE

Flat Glass Plants                           12

Plants visited                              14

Primary Flat Glass Manufacturing            20
  Production Data

Automotive Glass Fabricating                21
  Production Data

Raw Wastewater, Plate Glass                 41
  Manufacturing Process

Raw Wastewater, Float Glass                 45
  Manufacturing Process

Raw Wastewater, Solid Tempered              50
  Automotive Glass Fabrication

Raw Wastewater, windshield                  55
  Fabrication Using Oil Autoclaves

Concentration of Wastewater Parameters      60

Water Effluent Treatment Cost -             93
  Plate Glass

Water Effluent Treatment Cost -             95
  Float Glass

Water Effluent Treatment Cost -             98
  Solid Tempered Automotive Glass
  Fabrication

water Effluent Treatment Cost -            100
  windshield Fabrication

Recommended Monthly Average Effluent       108
  Limitations Using Best Practicable
  Control Technology Currently Available

Recommended Monthly Average Effluent       116
  Limitations Using Best Available
  Control Technology Economically
  Achievable

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                            SECTION I

                           CONCLUSIONS
That part of the glass manufacturing  industry  covered  in  this
document  is  classified  into six subcategories.  The first four
subcateijories refer to primary glass manufacturing.  The last two
subcategories deal with automobile window glass fabrication.  The
subcategorization is based on differences in  production  process
and  waste water characteristics.  Factors such as raw materials,
age and size of production facilities, and  applicable  treatment
technology  do not provide significant bases for differentiation.
The subcategories indicated, are as follows:

                1.  Sheet Glass Manufacturing
                2.  Rolled Glass Manufacturing
                3.  Plate Glass Manufacturing
                4.  Float Glass Manufacturing
                5.  Automotive Glass Tempering
                6.  Automotive Glass Laminating
Recommended effluent limitations and waste  control  technologies
to  te  achieved by July 1, 1977 and July 1, 1983, are summarized
in Section II.  It is estimated  that  the  investment  costs  of
achieving the 1977 limitations and standards by all plants in the
industry is less than $900 thousand excluding costs of additional
land acquisition.   The costs of achieving the 1983 level is esti-
mated to be an additional $2.3 million over the 1977 level.

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                           SECTION II

                         RECOMMENDATIONS
The  recommended  effluent  limitations for the pollutant  consti-
tuents of major significance are summarized  below   for  the   six
subcategories  of  the  glass manufacturing point source category
included in this document.

Using the Best Practicable Control Technology Currently Available
the daily maximum limitations are as follows:
     Sheet Glass

     Rolled Glass

     Plate Glass
       kg/metric ton
         (Ib/ton)

     Float Glass
       g/metric ton
       (Ib/ton)

     Automotive Glass
     Tempering
       g/sq m
       (Ib/ton)

     Automotive Glass
     Laminating
       g/sq m
       (Ib/ton)
                         Suspended
                          solids
             Oil

No waste water discharge

No waste water discharge
  2.76
 (5.52)
              Total
            Phosphorus
  2.00
 (0.0040)
  1.95
 (0.40)
  4.40
 (0.90)
 1.40
(0.0028)
 0.64
(0.13)
 1.76
(0.36)
 0.05
(0.0001)
   1.07
  (0.22)
       PH
   Between 6.0 and 9,0  (all subcategories

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Using the Best Available control Technology Economically Achieva-
ble, no discharge of process waste water pollutants to  navigable
water   is   recommended   for   the   sheet   and  rolled   glass
subcategories.    The   daily   maximum   effluent    limitations
recommended for the other subcategories are as follows:
     Plate Glass
       kg/metric ton
         (Ib/ton)

     Float Glass
       g/metric ton
       (Ib/ton)

     Automotive Glass
     Tempering
       g/sq m
       (Ib/ton)

     Automotive Glass
     Laminating
       g/sq m
       (Ib/ton)

       PH
                         Suspended
                          Solids     Oil
 0.045
(0.090)


 0.70      1.40
(0.0014)  (0.0028)
 0.24
(0.05)
 0.88
(0.18)
 0.49
(0.10)
 1.76
(0.36)
                     Total
                     Phosphorus
              0.05
             (0.0001)
 0.30
(0.06)
  Between 6.0  and 9.0 (all subcategories)
Recommended effluent limitations and standards of performance  for
new  sources  are  no  discharge for the sheet, rolled, and plate
glass manufacturing subcategories and the Best Available  control
Technology  Economically Achievable for flat glass manufacturing!
and automotive glass tempering and automotive glass laminating.

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                           SECTION III
                          INTRODUCTION
PURPOSE ANC AUTHORITY
Section 301 (b) of the Act requires the achievement by  not  later
than  July  1,  1977,  of effluent limitations for point sources,
other than publicly owned treatment works, which are based on the
application of the best practicable control technology  currently
available  as  defined  by  the Administrator pursuant to Section
304(b) of the Act.  Section 301(b) also requires the  achievement
by not later than July 1, 1983, of effluent limitations for point
sources,  other  than  publicly  owned treatment works, which are
based  on  the  application  of  the  best  available  technology
economically  achievable  which will result in reasonable further
progress toward the national goal of eliminating the discharge of
all pollutants, as  determined  in  accordance  with  regulations
issued  by  the  Administrator  pursuant to section 304(b)  of the
Act.  Section 306 of the Act  requires  the  achievement  by  new
sources  of  a  Federal standard of performance providing for the
control  of  the  discharge  of  pollutants  which  reflects  the
greatest  degree  of  effluent  reduction which the Administrator
determines to be achievable through the application of  the  best
available  demonstrated  control technology, processes, operating
methods, or other alternatives, including, where  practicable,  a
standard permitting no discharge of pollutants.

Section  304(b)  of the Act requires the Administrator to publish
within one year of enactment of the  Act,  regulations  providing
guidelines  for  effluent limitations setting forth the degree of
effluent reduction attainable through the application of the best
practicable control technology currently available and the degree
of effluent reduction attainable through the application  of  the
best   control   measures   and  practices  achievable  including
treatment techniques, process and procedure  innovations,  opera-
ting  methods  and  other alternatives.  The regulations proposed
herein set forth  effluent  limitations  guidelines  pursuant  to
Section  304(b) of the Act for certain subcategories of the glass
manufacturing point source category.   They include  sheet  glass,
rolled  glass,  plate  glass,  and float glass manufacturing, and
automotive glass tempering and laminating.

Section 306 of the Act requires  the  Administrator,  within  one
year  after a category of sources is included in a list published
pursuant to Section  306 (b)   (1)   (A)   of  the  Act,  to  propose
regulations establishing Federal standards of performance for new
sources  within  such categories.  The Administrator published in
the Federal Register of January 16,  1973 (38 F.R.  1624),   a  list
of  27  source  categories.    Publication of the list constituted
announcement of the Administrator's  intention  of  establishing,
under  section  306,  standards  of performance applicable to new
sources within the flat glass industry subcategory as  delineated

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above,  which  was included within the list published January 16f
1973.

SUMMARY  OF  METHODS  USED  FOR  DEVELOPMENT  OF   THE   EFFLUENT
LIMITATIONS GUIDELINES AND STANDARDS OF PERFORMANCE
Purpose and Authority

The  effluent limitations guidelines and standards of performance
proposed herein were developed  in  the  following  manner.   The
point  source  category  was first categorized for the purpose of
determining  whether  separate  limitations  and  standards   are
appropriate   for   different  segments  within  a  point  source
category.  Such subcategorization was  based  upon  raw  material
used, product produced, manufacturing process employed, and other
factors.  The raw waste characteristics for each subcategory were
then identified.  This included an analyses of (1)  the source and
volume  of water used in the process employed, and the sources of
waste and waste waters in the plant;  and  (2)  the  constituents
(including   thermal)    of  all  waste  waters;  including  toxic
constituents and other constituents which result in taste,  odor,
and  color  in  water, or aquatic organisms.   The constituents of
waste waters which should  be  subject  to  effluent  limitations
guidelines and standards of performance were identified.

The  full  range  of  control and treatment technologies existing
within  each  subcategory  was  identified.   This  included   an
identification of each distinct control and treatment technology,
including both inplant and end-of-process technologies, which are
existent  or  capable of being designed for each subcategory.  It
also included  an  identification  in  terms  of  the  amount  of
constituents  (including thermal) and the chemical, physical, and
biological characteristics of pollutants, of the  effluent  level
resulting  from  the  application  of  each  of the treatment and
control technologies.   The problems, limitations and  reliability
of  each  treatment  and  control  technology  and  the  required
implementation time was also identified.  In addition,  the  non-
water  quality  environmental impacts, such as the effects of the
application of such technologies upon other  pollution  problems,
including  air,  solid  waste,  noise  and  radiation  were  also
identified.  The energy requirements of each of the  control  and
treatment  technologies was identified as well as the cost of the
application of such technologies.

The information, as outlined above, was then evaluated  in  order
to  determine  what  levels  of  technology constituted the "best
practicable  control  technology  currently   available",   "best
available  technology  economically  achievable",  and  the "best
available demonstrated control technology,  processes,  operating
methods,   or   other   alternatives".    In   identifying   such
technologies, various factors were  considered.   These  included
the  total  cost  of application of technology in relation to the
effluent reduction benefits to be achieved from such application.

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the  age   cf  equipment  and  facilities  involved,  the  process
employed,  the  engineering aspects of the application of various
types of control techniques, process changes,  non-*water  quality
environmental  impacts   (including energy requirements) and other
factors.

Basis for  Guideline Development

The data for identification and  analyses  were  derived  from  a
number  of  sources.   These  sources  included EPA and industry-
supplied information, published literature, and  on-site  visits,
interviews,   and   sampling   at  typical  or  exemplary  plants
throughout the United States.  References used in the  guidelines
for  effluent  limitations  and  standards  of performance on new
sources reported herein are included  in  Section  XIII  of  this
document.
Three  types  of  waste water data were analyzed.  These are RAPP
data, industry supplied data, and data derived from the  sampling
of   typical  or  exemplary  plants.   The  data  retrieval  form
illustrated in Figure 1 was developed to aid in the collection of
data during interviews and plant visits and was supplied  to  the
industry to indicate the types of data required for the study.

The  data  was  analyzed with the aid of a computer program which
provided the capability for summing the data for each plant where
multiple discharges existed, averaging the data  for  each  plant
where  multiple  data  sets  were  available,  and  comparing and
averaging the data for all  plants  within  each  subcategory  to
determine values characteristic of a typical plant.  Input to the
computer   for  each  plant  consisted  primarily  of  the  plant
production rate, the waste water flow rate, the concentration  of
each  constituent  plant  intake  water,  the average and maximum
concentrations of each constituent in the waste water,  and  some
descriptive   information   regarding  existing  waste  treatment
methods, subcategory type, and sampling methods.

An example of the computer printout is the  hypothetical  summary
of  effluent  suspended  solids data for plate glass plants using
lagoon treatment illustrated in Figure  2.   The  pound  per  day
increase,  mg/1  increase and pounds added per day per production
unit are calculated.  Data from  all  of  the  plants  listed  is
summarized  in  terms  of the average, standard deviation (SIGMA)
and minimum and maximum values for the data listed.

The name, location, and applicable  manufacturing  processes  for
the  plants  contacted  in  this  study  are  listed  in Table 1.
Twenty-three plants supplied some type of usable  information  or
data for computer analysis.  RAPP data was available and used for
10 plants.

Ten  plants  covering  various  manufacturing  combinations  were
visited.  The subcategories covered are listed in Table  2  along

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with the type of data collected,  six of the plants were sampled,
some  with  more  than  one subcategory.  One plate, one float, 2
solid  tempered  automotive,  and  3  laminating  processes  were
sampled.

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             SPA TUT GLASS SlOtS (Coffltd.)

     9.   Temperature
    10.   pH
    11.   Other (All available information should be collected)
0.   Treatment  Ifethods
     1.   Wastewater Source and Tblune
     2,   Season for Treatment
     3.   Describe Treatment System and Operation
     4.   Type  end Itoantity of Cbemlcale Used
     5.   Available Information on Treated Wastewater (taality
          a.   BOD
          b.   COD
          a.   Total Solids
          d.   Suspended Solids
          e.   Qteaolied Solids
          f.   Oil and &eaae
          g.   Phosphorus
          b.   MBAE
          1.   Temperature
          J-   PH
          k.   Other (111 available Inforaatton should IK collected)
     6.   IB .Any Known Tozic Ifcterial In the Wastewater?
B.   Waetewater Becjcle
     1.   Is Jtay WastevKter Beoycled Presently?
     2.   Can Wastemter be EteoycleilT
                          -3-
                  BPA FIAT (HJiSS STimt (Contd.).
      I.    Di Plant Ifetbods of Water Conservation Bad/or Wast*
           Reduction
      J.    Identify Any Air Fbllution, tolse  or Solid Wastes Resulting
           from Treataent or Other Control IfetLods.  Hov Is the Solid
           Waste IBsposed oft
      K.    Coat Information (Belated to later pollution control)
           1.   Treatnent plant and/or Eqaipaent Cost
           2.   Operating Coats (personnel, malntenatice, etc.)
           3.   ft-er Coats
           4.   BstlBBted EqolpKnt Life
      L.    Water fttUotlon Control Ifethods Being Considered for Future
HI   COOUNQWATIB
      A.    Process Steps Beqairing Cooling Water
      B.    Beat Bsjeetlon. acquirements (BTUAoor)
      C.    Type of Syfftea (Once through or recycle)
      D.    Water Temperatures and Flow Bate
           2.   Output
           3.   Flow Bate
           Cooling Tower
           1.   Direct or IwUreet
               Slowdown Bate
               Slowdown Control Method
               Type ttod £iantlty of Water Treatment Cheaicals Used
               Available Information on Slowdown Water
                                                                                                  F.
                                                                                                       Type and ftiantlty of Chemicals Used for Once Through
                                                                                                       Cooling Water Treataelrt
                                                                                                  BOIIZR
                                                                                                  A.   Capacity
                                                                                                  B.   Slowdown
                                                           FIGURE    I    (CONTD.)
                                                       DATA   RETRIEVAL   FORM

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PART A AND a PARAMETERS OF INTAKE WATER AND DISCHARGE.  BREAKDOWN ay PLANT
       PLANT    INF.
                CONC.
  MGD     GPM   MG/L
             EFF,   CONC,
             AVE.   MAX
             MG/L   MG/L
                                         LBS ADDED PER
LB/DAY INCREASE   MG/L INCREASE UNIT/DAY   PRODUCT UNIT
AVE        MAX    AVE   MAX            AVE      MAX      SAMPLE TYPE
ITEM NO,
530. TOTAL SUSPENDED SOLIDS
  WE» XYZ GLASS COMPANY
 2,1     1458.33 11.     30,

NAME" A8C GLASS INDUSTRIES
 5«96    4138.89 60.     75,
                         PRODUCTION* 100.   TONS/DAY»LAGOON»PLATE
                     375.    332.766 6375.09 19.     364.    100,

                         PRODUCTION* 300.   TONS/DAY»LAGOON»PLATE
                     425.    745.596 18142.8 15*     365.    300,
                                         3,32766 63.7509COMP*MP227


                                         2*48532 6Q.V761COMP.MP275

 8BC6    5597.22 71.     105%    800,    1078.36 24517.9 34.     729*    400.    5.81298 124.227
 4.03    2798.61 35.5    52.5    400,    539.181 12259.  17.     364.5   200,    2.90649 62.1135
 2.72943 1895.44 34.6482 31.8198 35.3553 291,915 8321.04 2.82843 0.7071  141.421 Q.59562 2*315-56
 5,96    4133,39 60.     75.     425,    745.596 18142.8 19.     365.    300.    3.32766 63.7509
 2.1     1458.33 11,     30,     375.    332.766 6375.09 15.     364,    100.    2.48532 6Q0476i
                                                                                                      TOTAL
                                                                                                      AVER,
                                                                                                      SIGMA
                                                                                                       MAX.
                                                      FIGURE  2
                                           SAMPLE COMPUTER  FORMAT

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Company Name



  ASG
  Chrysler



  CE
                                     TABLE 1



                                FLAT GLASS PLANTS





                        Plant Location



                            Greenland, Tenn.



                            Kingsport, Tenn.



                            Qkmulgee, Qkla.



                            Jeanette, Pa.



                            Detroit, Mich.



                            Fullertpn, Calif,



                            Erwin, Tenn.



                            Floreffe, Pa.



                            St. Louis, Mo.



                            Dearborn, Mich,



                            Nashville, Tenn.



                            Fort Smith, Ark.



                            Millbury, Ohio



                            Carleton, Mich.



                            Detroit, Mich.



                            E, Toledo, Ohio



                            Rossford, Ohio



                            ottowa. 111.



                            Lathrop, calif.



                            Creighton, Pa.



                            Carlisle, Pa,



                            Cumberland, Md.





*  This operation has reportedly been closed
  Ford







 Fourco



 Guardian
 LOF
 PPG
Applicable Process



      P




      R




      S




      s




      L, T




      R




      R




      R




      R




      F, L, T




      F, L, T




      S




      T




      F




      L




      F, L, T




      F, P,* T




      F, L, T




      F, L, T




      L




      F




      F, P
                                12

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Company irWame

PPG
Safelite



Safetee

Shatterproof
     TABLE I  (Contd.)

     FLAT GLASS PLANTS

Plant Location

      Meadville, Pa.

      Crystal City, Mo.

      Henryetta, Okla.

      Mt. Vernon, Ohio

      Clarksburg, W. Va<

      Mt. Zion, 111.

      Fresno, Calif.

      Greensburg, Pa.

      Crestline, Ohio

      Tipton, Pa.

      Wichita, Kans.

      Enfield, N. C.

      Philadelphia, Pa.

      Detroit, Mich.
Applicable Process

      F

      F

      s

      s

      s

      s

      s

      L

      T

      T

      L

      L

      L

      L
Note (1) F = Float Glass
         P = Plate Glass  (Including grinding  and  polishing)
         R = Rolled Glass
         S = Sheet Glass
         L = Windshield Fabrication (laminating)
         T = Solid Tempered Automotive Fabrication
                               13

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                                    TABLE 2
                                 PLANTS VISITED
Plate
Float
Rolled
Sheet
Automotive Tempering
Automotive Laminating
Combined Float, Auto. Laminating
  and Auto. Tempering
Combined Float, Plate and Auto.
  Tempering
(1)  - Individual process or subcategory
(2)  - End-of-Pipe including all  process  and
      auxiliary wastes
  Type of
Data Obtained
         (2)
     (D  (2)
    No Process
     Waste
    No Process
     Waste
     (1)  (2)
     (1)  (2)

     d)  (2)

     (1)  (2)
                                14

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GENERAL DESCRIPTION OF THE INDUSTRY
The  U.S.  Bureau  of Census, Census of Manufacturers, classifies
the flat glass  manufacturing  industry  as  Standard  Industrial
Classification   (SIC)  group  code  number  3211  under  the more
general category of Stone, Clay,  Glass,  and  Concrete  Products
(Major  Group  32) .   The  four-digit  classification code  (3211)
comprises  industrial   establishments   primarily   engaged   in
manufacturing  flat  glass and flat glass products from materials
taken from the earth in  the  form  of  sand.   This  study  also
includes  some  plants  which  are  engaged in the fabrication of
glass products (automobile window  glass)  from  purchased  glass
which  is  covered  under  SIC  group  code  number  3231,  Glass
Products, Made of Purchased Glass.

Origin and_HigtQr.y

Glass is thought to have been made in Persia 7000 years  ago  and
is  known  to have been produced 2000 years ago in Egypt.  It was
first used for gems and was later made into hollow  vessels  such
as  jars  and vases.  A circular piece was used for a window in a
bath house in Pompeii sometime between 600 B.C.,  when  the  city
was  founded,  and 79 A.D. , when it was destroyed by the eruption
of Mt. Vesuvius.  The glass was made by casting  and  then  drawn
with  pincers.   The glass blowpipe was invented at the beginning
of the Christian  era  and  led  to  two  important  methods  for
manufacturing  flat  glass;  the  crown  process and the cylinder
process.  In the crown process (which was thought  to  have  been
invented  by  the  Syrians) ,  a sphere was blown, an iron rod was
attached to the sphere opposite the blowpipe,  and  the  blowpipe
was cracked off.   The iron rod was then used to spin the reheated
sphere  until  it  opened to a flat circular sheet.  Glass-making
was introduced in America by the English,  and  the  first  glass
factory   in   America  was  erected  by  the  beginning  of  the
seventeenth century at Jamestown, Virginia.

During the nineteenth century, the crown process of  making  flat
glass  was  replaced  by the cylinder process in which a cylinder
was blown, the ends were cracked  off,  the  cylinder  was  split
along the side, and then reheated so that it could be opened into
a  flat  sheet.   The  cylinder  process  did away with the thick
center and thick edge  that  were  characteristic  of  the  crown
process*   In  addition,  larger sheets could be formed.   Various
improvements were made  in  mechanizing  the  process,  including
using compressed air for blowing.

In 1904, a patent was granted to Emile Fourcault in Belgium for a
process  in  which  a flat sheet of glass could be drawn directly
from a bath of molten glass.  Two other  methods  were  developed
for  making sheet glass at about the same time in America.   These
were the Colburn (or Libbey-Owens)   process  and  the  Pittsburgh
process.    All  three  processes  are  still  in  use  and  many

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improvements have  been  made  since  the  original  development.
Although  sheet glass has a high surface finish, the surfaces are
inherently wavy and are unsuitable for mirrors or  large  windows
in  which  undistorted  vision  is  desired.   This  fault can be
overcome by grinding and  polishing  the  sheet  glass,  although
ground  and polished glass is produced today by the plate process
and, to a lesser extent, by the rolled process.

The earliest plate  glass  was  produced  by  a  casting  process
invented in France in the middle of the seventeenth century.  The
glass  was  melted  in pots, poured onto a casting table and then
leveled to the required thickness with a roller.  The  glass  was
allowed  to  cool  and  was then ground with sand and water using
finer grades of sand as the grinding progressed.  The  glass  was
then  polished  with  feltcovered wheels fed with a fine abrasive
slurry of iron oxide.  These basic grinding and  polishing  steps
are  in use today, although continuous processes are now employed
in manufacturing ground and polished  plate  glass.   The  latest
method  for  producing  high  optical-quality  glass is the float
process, introduced by Pilkington Brothers Limited in 1959.   The
method  gets  its name from that part of the process in which the
glass is drawn across a bath of molten tin.  Heat is applied and,
together with the effect of gravity, a distortion-free  sheet  of
glass  is  produced  which  has the high surface-quality of sheet
glass.  Float glass is  rapidly  replacing  ground  and  polished
plate glass.

Description of Manufacturing Methods

Manufacture  of the basic sheet of flat glass from sand and other
raw materials is defined as  primary  flat  glass  manufacturing.
Sheet,  rolled,  plate,  and  float  glass are primary flat glass
products.  The primary glass sheets may be used directly  or  may
be  fabricated  into  glass  products  as  indicated in Figure 3.
Among the many fabricated products are mirrors and  other  coated
glass,  automotive and architectural tempered glass, windshields,
and numerous  speciality  products  such  as  bulletproof  glass,
basketball backboards, and glass hot plates.  Tempered automobile
glass and windshields are the only fabricated products covered by
this study.

Primary Flat Glass Manufacturing-

Flat  glass  is  manufactured by melting sand together with other
inorganic materials and then forming the  molten  material  to  a
flat  sheet.   Within  the  primary  flat glass industry, several
distinct methods are used to make  flat  glass.   These  are  the
float,  plate,  sheet,  and  rolled  processes.  Although the raw
materials and the melting operations are  essentially  the  same,
each process uses a different method for forming the molten glass
into  a  flat  sheet.   In  the float process, the glass is drawn
across a molten tin  bath  while  in  the  plate  process,  rolls
control the initial thickness with the final thickness determined
by  grinding  and  polishing.   The glass is formed by a vertical
                               16

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                                     RAW MATERIAL  STORAGE
                                      RAW MATERIAL  MIXING
                                            MELTING
SHEET
PLATE (G&P)
FLOAT
      ARCHITECTURAL
       FABRICATION
                   AUTOMOTIVE
                   WINDSHIELD
                   FABRICATION
             ROLLED
      SOLID TEMPERED
     AUTOMOTIVE GLASS
        FABRICATION

MISCELLANEOUS &
 ARCHITECTURAL
  FABRICATION
                                           CONSUMER
                                            FIGURE 3

                                     FLAT GLASS INDUSTRY

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drawing process in the sheet process.  Finally, texturizing rolls
are used  to  impart  various  surface  textures  in  the  rolled
process.

All  primary  glass  may  be  used as architectural glass.  Plate
glass is used in preference  to  sheet  where  a  distortion-free
glass  is  desired.   Rolled  glass is used where a decorative or
translucent surface is desired.  Float glass is used for the same
purposes as plate glass, both of  which  can  serve  as  the  raw
material  for  automobile  window  glass.   Fabricated  glass  is
produced using all of the primary glass types.

Automobile Window Glass Fabrication-

Automobile  window  glass  fabrication  is   divided   into   two
processes.   Windshield laminating consists of bonding two layers
of glass to an inner layer of vinyl plastic.  The major  unit  of
equipment  in  the  process  is  the  autoclave  which is used to
complete  the  bonding  operation  under   conditions   of   high
temperature  and  pressure.  The purpose of laminating is to make
the glass shatter resistant.  Unlike windshields, side  and  back
lights  (windows)  are fabricated from solid pieces of glass.  The
process includes  edge  grinding,  bending  and  tempering.   The
purpose  of  tempering  (heating, followed by rapid cooling) is to
increase the strength of the glass over that of ordinary annealed
glass and to cause it  to  shatter  into  small  rounded  pieces,
should it be broken.

PRODUCTION AND PLANT LOCATION

There  are  a  total  of  36  plants  owned by 11 companies which
manufacture flat glass and fabricate automobile window  glass  in
the  United  states  (See  Figure  4  and Tables 3 and 4), with a
combined daily processing capacity of 10,700 metric tons   (11,800
short  tons)  of  primary  flat glass products and 173,000 square
meters (1.86 million square feet) of automotive  glass  products.
The  daily  capacity  of an average plant engaged in primary flat
glass manufacturing is 413 metric tons (455 short  tons).   These
plants  range in size from 54 metric tons (60 short tons) per day
to 1090 metric tons (1200 short tons) per  day.   (Note:    During
the  course  of this study one plate process was reported to have
closed.  The following data, however, include this operation.)

The daily capacity of an  average  plant  engaged  in  automotive
glass fabrication is 10,800 square meters.  These plants range in
size  from  2,000  square  meters (22,000 square feet)  per day to
24,700 square meters (266,000 square feet) per day.

Total employment in the industry is 24,000 with an average of 670
employees per plant.  Plant employment ranges from about  100  to
2900.   It  should  be noted that employment figures are based on
plant totals.  Many of the plants carry on  production  processes
(such  as  architectural glass fabricating)  which are not covered
by the study.
                                 18

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                                FIGURE 4
LOCATION OF FLAT GLASS MANUFACTURING PLANTS WITHIN  THE UNITED STATES, 1973

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PRIMARY FLAT GLASS MANUFACTURING

         PRODUCTION DATA
Number of Plants

Total Capacity
 (metric tons/day)

Average Plant Size
 (metric tons/day)

Range (metric
ton/day)

Total Capacity
 (short tons/day)

Average Plant size
 (short tons/day)

Range (short
tons/day)

Plants Discharging to
Municipal Treatment
Systems
  11

6430


 580
  3

970


330
   8

2720


 340
7080
 640
                1070
                 360
         3000
          370
         20%
                                        5

                                      670


                                      140
      330-1090  250-390   150-600   55-230
           740
           150
      360-1200  270-425   170-660   60-250
                     NO        NO
                   Process   Process
                    Waste     Waste
                20

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                             TABLE 4
                  AUTOMOTIVE GLASS FABRICATING
                         PRODUCTION DATA  -
Number of Plants
Total Capacity  (sq m/day)
Average Plant Size (sq m/day)
Range (sq m/day)
Laminating
    11
75,200
 6,900
65-15,800
Total Capacity (sq ft/day)           810,000
Average Plant Size (sq ft/day)       7U,000
Range (sq ft/day)              7,000-170,000
Plants Discharging to
  Municipal Treatment
  Systems
  3096
          9
       97,500
       10,900
     1,390-24,700

     1,050,000
       117,000
15,000-266,000

        20%

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GENERAL PROCESS DESCRIPTION
Primary Flat Glass Manufacturing

Primary flat glass manufacturing consists of  batching,  melting,
forming,   annealing,  and  cutting.   Grinding,  polishing,  and
washing are  included  in  the  plate  process,  and  washing  is
included  in  the  float process.  All of the processes use water
for cooling.  The basic unit of production for primary flat glass
manufacturing is the metric ton  (or short ton in  English  units)
and is based on the amount of glass drawn from the melting tank.

These  units  were chosen because this is the most common measure
of production for primary glass manufacturing and the  data  will
be  readily  available for enforcement personnel.  In some cases,
production is measured in terms of tons of raw  material  fed  to
the  furnace,  but  this  is  easily converted by subtracting the
weight volatilized during the melting process.  A weight loss  of
18% was assumed for this study.

Raw Materials-

The most common type of flat glass produced is the soda-lime type
which  is  also  used  for bottles, light bulbs, and eye glasses.
The basic composition remains the same,  although  there  may  be
minor  differences  in  raw material composition depending on the
manufacturer and the process (float,  plate,  sheet  or  rolled).
The  principal  ingredient  is  sand (silica), which accounts for
about half of the batch.  Other major ingredients  are  soda  ash
(sodium   carbonate),  limestone  (calcium  carbonate),  dolomite
(magnesium carbonate), and cullet.  soda ash is added  to  reduce
the  viscosity  of  the melt and thus lower melting temperatures.
Limestone  and  dolomite  are  added  to  improve  the   chemical
durability  of  glass.   Carbon  dioxide is evolved from the soda
ash, limestone, and dolomite -during the melting process,  leaving
sodium oxide, calcium oxide, and magnesium oxide in solution with
the  silica  (silicon dioxide).   The amount of evolution of carbon
dioxide is about 1856 by-weight of the total charge less cullet.

Cullet is waste glass that is inevitably produced  in  the  glass
manufacturing  process, both inadvertently and intentionally, and
may be 25X of the total amount of glass removed from the  melting
tank.   The  cullet  is  reprocessed  with  the raw materials and
actually improves the melting qualities of the batch  because  of
its  tendency  to  melt  faster  than the other ingredients, thus
providing starting points from which  the  melting  can  proceed.
Other   ingredients   are  often  added  to  accomplish  specific
purposes.  For example, iron oxide is added in small  amounts  to
produce the blue-green color in tinted automotive glass.
                              22

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Batching-

In the batching operation, the raw materials are brought together
and  mixed to a homogeneous consistency.  Good mixing is very im-
portant  in  maintaining  uniform  physical  properties  in   the
finished product.  Likewise, impurities in the raw materials must
be  kept  to  a  minimum  to  avoid imperfections which result in
rejection of the finished product.

Melting-'

In the melting operation, the raw materials are continuously  fed
into  the  refractory-lined  melting  tank  where they are heated
using fuel oil or natural gas.  Because of the high  temperatures
involved, all melting tanks use large amounts of cooling water to
maintain structural integrity.

Forming-

Up to this point, the operations are essentially the same regard-
less  of  process.   As  the  molten glass progresses through the
melting tank, it  is  allowed  to  cool  somewhat  to  facilitate
removal  from  the tank in a continuous ribbon.  It is the manner
in which the ribbon is removed from the tank and  the  subsequent
means used to effect dimensional control and surface texture that
distinguishes  between  the sheet, plate, rolled, and float glass
processes.

The glass is vertically drawn from the melting tank in the  sheet
glass  process.  The drawing process is started by lowering a bar
into the molten glass and then pulling it out.  The glass adheres
to the bar and forms a continuous ribbon as the  bar  is  raised.
The  glass cools and hardens as it is raised, after which powered
rollers are applied  to  the  ribbon  to  maintain  a  continuous
drawing  operation.   The thickness of the glass is approximately
inversely proportional to the drawing speed.

In the plate process, the molten glass flows by gravity to a pair
of water-cooled forming rolls which determine  the  thickness  of
the glass.  The rolled-glass operation is similar except that the
rolls  may  be  texturized  to  impart a decorative and diffusing
surface.  Wired glass is another  product  of  the  rolled  glass
operation.   Two  pairs  of forming rolls are used to produce two
ribbens of glass.   A  wire  mesh  is  inserted  between  the  two
ribbons  which are then brought together while the glass is still
hot and soft so that bonding occurs.

In the float process, the glass is passed out of the melting tank
onto a molten-tin surface.  Heat and the force of gravity combine
to provide a product with optical qualities similar  to  that  of
ground and polished plate glass.   The advantage of the float pro-
cess  over  the  plate process is that grinding and polishing are
not required.
                            23

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Annealing-^

Each of  the  primary  manufacturing  processes  incorporates  an
annealing  lehr in which internal stresses are removed by heating
the  glass  to  a  uniform  temperature  followed  by  controlled
cooling.  Following annealing, the glass is cut.

Grinding and Polishincf-

Plate  glass  must be ground and polished to achieve the flat and
parallel surfaces that are required  for  good  optical  quality.
Large  rotary grinding machines are used.  The cast iron grinding
tools are called laps, and use  a  grinding  medium  which  is  a
slurry  of  sand  and  water.  Coarse sand is used in the initial
stages of grinding, but progressively finer sand is used  as  the
glass  passes  through  successive grinding stages.  The grinding
slurry  is   recycled   through   classifying   equipment   which
continuously  grades  the  sand  and  feeds  each  section of the
grinding machine with a slurry of water and  appropriately  sized
sand.   Sand  and  glass  grindings  that are too fine to use for
grinding are discharged in a continuous blowdown.  It  should  be
pointed  out  that  the  classifying  operation  is  sensitive to
contamination.  Contaminants may cause an upset  resulting  in  a
shutdown  of  grinding  operations.   A  matter  of  days  may be
required to restore proper operation.

Polishing is accomplished with rotary equipment using animal felt
as the polishing surface and a slurry of water and iron oxide  or
cerium  oxide  as  the  polishing medium.  Grinding equipment and
some  polishing  equipment  in  use  today  is  of   the   "twin"
configuration  in  which  both  sides of the glass are ground and
polished concurrently.  With "single" polishing equipment,  glass
is  conveyed  through the polishing operation on tables that have
been coated with  gypsum  or  some  other  supporting  medium  to
prevent  movement  of  the glass.  During grinding and polishing,
the glass thickness is reduced by approximately 15 percent.

Washing-

Washing is always  performed  in  the  plate  process  to  remove
residual  grinding  slurry  and  polishing rouge,  in some cases,
float glass is washed to remove sodium sulfate which forms on the
glass as a result of a chemical  reaction  with  sulfur  dioxide.
The  sulfur  dioxide  is  sprayed  to prevent roller marks as the
glass passes through the annealing lehr.  No washing is done as a
part  of  the  sheet  and  rolled  glass  primary   manufacturing
processes,  sheet and rolled glass manufacturers may also do some
fabricating  (usually architectural)  in addition to their primary
manufacturing  operations.   In  most  cases,  glass  washing  is
required.  The washing is a fabricating step and, as such, is not
a part of primary manufacturing operations.
                              24

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 Cooling-

 Large  amounts  of  heat  energy are used in the manufacturing of
 flat glass and lead to large usages of cooling water  to  protect
 the  equipment  from  excessive  temperatures.   Cooling water is
 required for all melting tanks, for the float bath in  the  float
 glass  process,  the  forming rolls in the plate glass and rolled
 glass processes, and for the drawing  kiln  in  the  sheet  glass
 process.   In  addition,  cooling water is required for the plant
 compressors and may also be used for the annealing lehr.

 Heat energy that is dissipated by cooling water  is  called  heat
 rejection  in this report.  Heat rejection is defined as the heat
 energy leaving the process in the discharge water minus the  heat
 energy entering the process in the intake water.

 For  primary manufacturing plants, most of the process waste heat
 is dissipated directly to the atmosphere.  Based  on  information
 from  one  source, the total heat energy required for manufacture
 of flat glass is about 3,000,000 kilogram-calories per metric ton
 (11,000,000 Btu/short ton)  of  glass  removed  from  the  melting
 tank.   Average  heat rejection by means of cooling water systems
 is about 600,000 kg-cal/ metric ton   (2,200,000  Btu/short  ton).
 Based on the large amounts of cooling water required, some plants
 have found it advantageous to be located near rivers while others
 use cooling towers or spray ponds to dissipate waste heat.

 It should te pointed out that the heat rejection values presented
 later  in  this  report  are  only  estimates.  Heat rejection is
 difficult to define because of varying  flow  rates  and  varying
 temperatures which can be caused by changes in intake temperature
 and  in process operating conditions.  For example, cooling water
 requirements for melting tank operations can vary over  the  life
 of  the  melting  tank  from one rebricking to the next.  Melting
 tanks require rebricking approximately every  four  years.   Over
 the  course  of  the four years, the melting tank brick work will
 degrade and molten glass leaks can occur in the walls.   A leak is
 repaired by locating an auxiliary cooler at the  hole  to  freeze
 the  molten  glass and, thus, plug the hole.   The addition of the
 cooler  results  in  increased  use   of   cooling   water   and,
 consequently, a higher heat rejection rate.

 Heat  rejection  was computed in two different ways.   For a once-
 through cooling system, it was necessary to determine the average
 intake and average discharge water temperatures and  the  average
 flow rate.   Unless continuous monitoring was  employed,  the values
had  to  be  estimated.   Heat  rejection for a recycling cooling
 system could be determined if the cooling  tower  or  spray  pond
make-up  water  flow rate was known.   Make-up requirements are an
 indication of the evaporation rate which is proportional  to  the
heat rejection rate.
                              25

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Automobile window Glass

Automobile   window   glass   fabrication   includes   windshield
laminating and side and back light  (side and back  window)  solid
tempering.    The   basic   unit  of  production  for  automotive
fabrication is expressed in square  meters  (or  1000  sg  ft  in
English units) of the surface area  (one side)  of finished glass.

These  units  were  chosen  because  they  are used at all of the
plants studied to measure  automobile  glass  production.   Waste
water  volume  and  characteristics  are  related   to the square
meters (square feet) of glass fabricated.


Binflgfrield Laminating-

Windshield laminating consists of bonding two  layers  of  glass,
which have been cut and bent to the proper size and curvature, to
an  inner  layer  of vinyl plastic.  Bending is accomplished in a
bending lehr.  Heat is  applied  to  the  glass  and  a  form  is
provided  to  assure the proper curvature.  Mating panes are bent
together to assure that  both  are  of  the  same  curvature.   A
parting  material  is  applied  to  the  panes  before bending to
prevent sticking.

Bonding of the two layers of glass to the vinyl plastic  is  done
in  two steps, sometimes referred to as prepressing and pressing.
Prepressing  is  generally  done   with   rollers.    The   large
manufacturers  do  their  final  pressing  in an oil autoclave in
which oil is the medium for transmitting pressure and temperature
changes to the windshield to induce bonding.  Oil autoclaves  are
typical for the industry.

Vinyl plastic sheet is purchased in rolls.  Before assembling the
plastic  into rolls, the manufacturer applies a coating of sodium
bicarbonate  to  prevent  sticking  of  adjacent  layers   during
shipment and storage.

Cutting  the glass .leaves a sharp edge so that most manufacturers
find it desirable to seam (sand or rough  grind)   the  edges  for
safety  in  handling.   Some manufacturers seam immediately after
cutting while others wait until after pressing.

Several washing operations are required.   The  glass  is  washed
before  bending to remove contaminants that could be baked on the
glass due to the high temperatures in the  bending  lehr;  before
prelamination   assembly  to  assure  cleanliness  of  the  inner
surfaces; and after pressing to remove the oil which  adheres  to
the  glass.   The  prelamination wash has been eliminated at some
plants.  Washing is also required to remove bicarbonate  of  soda
from  the  vinyl  plastic  prior  to  prelamination assembly.  If
seaming occurs after  autoclaving,  the  glass  is  again  washed
before shipment to the customer.
                              26

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Large  amounts of heat are required in the autoclave operation to
produce  the  temperatures  necessary  for  bonding.    Following
lamination, non-contact cooling water is used to cool the glass.

A   few   small  manufacturers,  producing  windshields  for  the
replacement windshield and recreational and farm vehicle markets,
are using air autoclaves.  In  the  air  autoclave,  air  is  the
medium  for  transmitting  the  required pressure and temperature
changes to the windshield.  The advantage of the air autoclave is
that it is not necessary to wash  the  glass  after  autoclaving;
however,  increased  handling may be required with an air system.
The trend in the industry is towards air  autoclaving.   Some  of
the  large  manufacturers  have indicated that any new laminating
facilities will be equipped with air autoclaves.           /

Automotiveisolid Tempering-

Production  of  automotive  side  and  back  lights  consists  of
cutting,   edge   grinding,   seaming,   drilling,  bending,  and
tempering.  The edges of side lights that will be  exposed  after
being  assembled  into the automobile (the edges that are exposed
when the window is rolled down)  are ground to a smooth radius for
appearance  and  safety.   The  other  edges  may  be  seamed  to
facilitate  safe  handling  during  subsequent fabricating steps.
Hole drilling is performed on some lights to provide for  special
fabricating requirements of the automobile manufacturer.  Bending
is accomplished in a bending lehr by heating the glass to achieve
the  proper curvature, and the glass is tempered by rapid cooling
after heating.  Either  air  or  water  quenching  may  be  used.
Tempered  glass  is  stronger than ordinary annealed glass and it
breaks into tiny rounded pieces that  will  not  cut  a  person's
skin.  Cooling water is required in the tempering hearth.

Edge  grinding  requires  the  use of a cooling solution which is
recirculated through settling tanks to remove the  glass  solids.
These  solids  are  disposed of as landfill.   Washing is required
before bending to remove  residue  from  the   edge  grinding  and
drilling operations.
                              27

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                            SECTION IV

                      INDUSTRY CATEGORIZATION
 The  segments of  the flat  glass  industry covered by this study are
 primary   flat   glass   manufacturing   and   automotive   glass
 fabrication.   A  general distinction can be  made  between  primary
 manufacturing and automotive fabrication based on differences in
 raw  materials used,  products  produced,  and  production  methods
 employed.     These  factors were   discussed  in  detail  in  the
 preceding  paragraphs.  The  expression  of primary  production  in
 terms   of  weight and fabricated production  in  terms of  area is an
 indication of the basic difference.

 The  following factors  were  considered   with respect to  further
 subcategorization within  the above  two general categories:

               Raw materials

               Age and  size  of production facilities

               Products and  production  processes

               Waste  water characteristics

               Treatment methods

 It   is  concluded that primary  flat  glass manufacturing  should be
 subcategorized   as   sheet,  rolled,  plate,    and    float   glass
 manufacturing and that automobile window glass  fabricating  should
 be   subcategorized   as automotive glass tempering and automotive
 glass   laminating.   Products  and   production   methods   are  the
 primary bases for subcategorization.

 Raw  Materials

 The  raw   materials  for  primary flat  glass manufacturing  do  not
 provide a  basis  for  subcategorization since they are  essentially
 the  same  regardless  of   the  process  and in  themselves have no
 direct  effect on  waste water quality.   The same reasoning applies
 to automotive fabricating in  which  the  raw  material   is  flat
 glass,  generally  from  the float process.

 Age  and size  of  Production Facilities

 Age  is  not  a   factor for the float process because it  has only
 been used  since 1959.  There are only three plate  lines  in   the
 country.   These  are the most modern as the older, less-efficient
 facilities have already been phased out.  Sheet and rolled  glass
 plants are of varying  age but since no process water is used,  age
 is   not  a  significant  factor  except  that  the  cooling water
 requirements  are  probably  greater  for  older   melting  tanks.
Laminating    and  tempering  facilities  are  continuously  being
                              29

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modernized so that plant  age  is  not  a  factor  in  automotive
fabrication.

Waste  water  volumes  and  flow  rates  expressed  in  terms  of
production do not vary significantly with respect to plant  size.
Basic   process   equipment   is  generally  the  same  for  each
sutcategory throughout the industry.  The larger the  plant,  the
more  parallel  equipment employed.  For these reasons, plant age
and size are not a basis for subcategorization.

Products_andL.Production_Processes

Readily  identifiable   production   methods   characterize   the
manufacturing   processes   by  which  the  various  primary  and
fabricated products are made.  The float process is characterized
by the molten  tin  bath;  the  plate  process  by  grinding  and
polishing; the rolled process by the texturizing rolls; the sheet
process  by  vertical  drawing; the laminating process by the oil
autoclave; and the  tempering  process  by  edge  grinding,  hole
drilling,  and  tempering.  Each of these processes has different
requirements  for  water,  resulting  in  different  waste  water
characteristics   and  treatment  requirements.   Heat  rejection
requirements  also  differ  for   the   different   manufacturing
processes.    The   variation   in  production  methods  forms  a
significant basis for subcategorization.   Many flat glass plants
have more than one  manufacturing  process  contributing  to  the
total  waste  stream.   A  typical multi-product plant may have a
float  line  as  well  as  automotive  laminating  and  tempering
facilities.   This  phenomenon  is  additional  justification for
subcategorization by  process.   Performance  standards  will  be
recommended  en a subcategory by subcategory basis.  In this way,
the total effluent limitation for a multi-product  plant  can  be
determined by summation.

w<*££e Water Characteristics

Waste  water  volume  and  characteristics  vary  widely  for the
different manufacturing processes.  No  process  waste  water  is
produced by rolled and sheet glass manufacturing.  A small volume
of  clean  water  results  from  washing  in  the  float process.
Grinding and  polishing  in  the  plate  process  produces  large
volumes   of  high  suspended  solids  waste  water.   Windshield
fabrication produces a lower volume of oily waste water and solid
tempered automotive glass production results  in  a  still  lower
volume  of  somewhat cleaner waste water.  The variation in waste
volume and characteristics is a basis for subcategorization.

Treatment Methods

Although   waste   water   volume   and   characteristics    vary
significantly,  applicable  treatment  methods are all related to
the removal of oil, and suspended and dissolved solids.  Some  of
the  same  treatment  methods  apply to more than one subcategory
                               30

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and, therefore, variation in treatment methods
basis for subcategorization.
is  only  partial
                                 31

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                            SECTION V

              WATER USE AND WASTE CHARACTERIZATION
Water  is used to some extent in all of the subcategories covered
by this study.  Cooling and boiler  water  are  required  at  all
plants.   Washwater  is  used in the plate, float, and automotive
fabrication subcategories for washing, and water is the  transfer
medium for grinding sand and rouge in the plate process.

Plant  water  is obtained from various sources including the city
water supply, surface, or ground water.  City water  is  used  in
almost  all  cases  where it is available, except for plate glass
manufacturing where large quantities of river water are used  for
grinding and polishing.

AUXILIARY WASTES

For  the purposes of this study, non-contact cooling, boiler, and
water treatment waste waters are considered auxiliary  wastes  as
distinguished  from process waste waters.  Process waste water is
defined as water which has come  into  direct  contact  with  the
glass,  and  include  such  sources  as  washing,  quenching, and
grinding and polishing.

Pretreatment requirements depend on the raw water quality and the
intended water use.  Cooling  water  pretreatment  practices  may
range from no treatment to coagulation-sedimentation, filtration,
softening,  or  deioriization.  Generally, treatment is sufficient
to prevent fouling of the cooling system by clogging,  corrosion,
or   scaling.   Boiler  water  treatment  is  related  to  boiler
requirements, but removing the suspended solids and  at  least  a
portion   of   the   dissolved  solids  are  generally  required*
Filtration, softening, aeration, and  deionization  are  done  as
necessary.   Washwater  must  be  low  in suspended and dissolved
solids to avoid spotting the glass,  city water  is  used,  where
available, or water from other sources is treated to obtain water
of  similar  quality.   In some cases deionized water is required
for final rinsing.

Waste waters from pretreatment systems are  highly  variable  and
depend  upon  the characteristics of the water being treated.  At
two plants in the same subcategory,  therefore,  no  pretreatment
may  be  required at one while coagulation-sedimentation, filtra-
tion, and deionization may be required at the other.   For  plants
with   the   same  system,  the  pretreatment  waste  volume  and
characteristics are also proportional  to  the  concentration  of
pollutants removed.

Cooling  and  boiler systems, associated water treatment require-
ments and waste water characteristics vary considerably among the
plants in the flat glass industry.   Existing cooling systems  in-
clude once-through and direct-contact and indirect-contact recir-
                             33

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culating  systems.   Highly variable cooling water treatments are
used in these systems.  Boiler systems may also vary considerably
in terms of chemical treatment  and  blowdown.   The  volume  and
characteristics  of  cooling and boiler waste waters are directly
related to the make-up water  characteristics  and  the  type  of
systerr employed.

Auxiliary waste waters are not unique to the flat glass industry.
Many  manufacturing  operations  throughout industry use the same
cooling, boiler, and water pretreatment systems.  Owing to  their
highly  variably  volume  and  characteristics,  auxiliary  waste
waters are not included in the effluent limitations and standards
of performance developed for  process  waste  waters.   Auxiliary
waste  waters  will be studied at a later date, and characterized
separately for industry in general.   The  values  thus  obtained
will  be added to the limits for process waste water to determine
the effluent limitations and standards  of  performance  for  the
total plant.

In  this  report, cooling requirements will be discussed in terms
of heat-rejection requirements.  Where appropriate, some  of  the
types  of systems used may be discussed; however, no attempt will
be made to define or categorize the equipment and  systems  used,
the    cooling-water   treatment   methods,   or   the   effluent
characteristics.  Water pretreatment methods  will  be  discussed
where  applicable  to process water treatment and washes that may
require deionized water will be noted.

SHEET GLASS MANUFACTURING

Sheet glass  manufacturing  operations  may  be  defined  as  the
processing of raw materials to form thin glass sheets of saleable
size.   Figure  5  is  a flow diagram indicating water usage with
respect to the manufacturing steps.   The  manufacturing  process
has  been  defined  in detail in section IV.  Non-contact cooling
water is used, but no process waste water  is  produced  by  this
subcategory.

Process Water and_Waste Water

The  only  water  used  in  the  process  is  42 I/metric ton (10
gal/short ton) added to the raw materials for  dust  suppression.
This is evaporated in the melting tank.

No  process  water is used and, therefore, no process waste water
is produced by the sheet-glass subcategory.  However,  it  should
be  noted  that  architectural  tempering  or  other waste water-
producing fabrication steps may be operated in the same  facility
in  which  sheet  glass  is produced.  The effects of fabrication
steps must be considered when analyzing the total effluent from a
sheet glass facility.

Cool inof
                               34

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      WATER
 42 L/METRIC TON
(10GAL/SHORTTON)
 COOLING WATER
RAW MATERIAL STORAGE
       MIXING
      MELTING
      DRAWING
                              ANNEALING
  COOLING WATER

          KG—CAL
 .772 X106 METRIC TON

       c   BTU
(2.78 X106 SHORT TON)
                               CUTOFF
                                       HEAVY GLASS
                                         *
                    RE-ANNEALING LEHR
                               CUTTING
                              PACKAGING
                               STORAGE
                               CONSUMER
                              FIGURE 5

                 SHEET  GLASS  MANUFACTURING
                          35

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In the sheet glass manufacturing process, cooling  water  is  re-
quired  for  the  melting tank, drawing kiln, compressors and the
reannealing lehr.  Average heat rejection for  plants  using  the
Pennvernon  process  is  772,000 kilogram-calories per metric ton
<2,780,000 Btu/short ton) with a range of  741,000  kg-cal/metric
ton   (2,670,000  Btu/short  ton)  to  877,000  kg-cal/metric  ton
(3,160,000 Btu/short ton).  Another sheet glass plant, using  the
Fourcault   process,   reports  heat  rejection  at  350,000  kg-
cal/metric ton (1,260,000 Btu/short ton).   The  reason  for  the
difference  in  heat rejection between the Pennvernon process and
the Fourcault process is the relative proximities of the  drawing
kiln  to  the  melting tank.  In the Fourcault process the molten
glass flows in a canal to the drawing kiln which is not as  close
to  the  melting tank as in the Pennvernon process.  By traveling
the longer  distance  (by  way  of  canals),  the  glass  has  an
opportunity to cool so that not as much cooling water is required
in  the  drawing kiln.  The Libbey-Owens process is also used for
making sheet glass.  No heat-rejection data  was  available  from
these plants.

ROLLED GLASS MANUFACTURING

Rolled  glass manufacturing consists of melting raw materials and
drawing the molten glass through rollers to form a  glass  sheet.
The  major  process steps and points of water usage are listed in
Figure 6.  Non-contact cooling water  is  used,  but  no  process
waste water is produced by this subcategory.

Process Water and Waste watey

Approximately  42  I/metric  ton  (10 gal/short ton) of water are
added to the raw materials for dust suppression.  This  water  is
evaporated in the melting tank.

No  process  water is used and, therefore, no process waste water
is  produced  by  the  rolled  glass  subcategory.    Fabricating
operations  generally  occur  in  con junction  with  rolled glass
manufacturing and  should  be  noted  that  numerous  and  highly
variable  waste  water  streams  may  result.   Although  primary
rolled-glass production is a dry process,  waste  waters  may  be
generated by a rolled glass facility because of fabrication waste
water.

Cooling

In  the  rolled-glass manufacturing process, cooling water is re-
quired for the melting tank, forming rolls,  annealing  lehr  and
compressors.   Although  no  heat-rejection data is available for
rolled glass plants, it is expected that heat rejection  require-
ments are similar to the plate glass process because of similari-
ties in process configuration.

PLATE GLASS MANUFACTURING
                               36

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      WATER
 42 L/METRIC TON
(10GAL/SHORTTON)
  COOLING WATER
(DATA NOT AVAILABLE)
RAW MATERIAL STORAGE
       MIXING
                                MELTING TANK
                                FORMING ROLLS
                                  ANNEALING
                                                              COOLING WATER
                                 INSPECTION
                                  CUTTING
              CUTTING
             PACKAGING
                                                       FABRICATION
             CONSUMER
                                FIGURE  6

                    ROLLED GLASS MANUFACTURING
                               37

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Plate glass manufacturing is the production from raw materials of
a   high-quality   thick   glass  sheet.   This  subcategory  has
historically been the greatest source of waste  in  the  industry
since large volumes of high suapended^solids waste water are pro-
duced.    Owing  to  high  production  costs  and  related  water
pollution problems, plate glass is being replaced by float glass.
Only three plate glass plants remain in the United  states.   The
major process steps and points of water usage are shown in Figure
7.

The typical plate glass manufacturing plant may be located in any
part of the country and is at least 12 years old.  Advanced plate
glass  manufacturing  technology  is  used, but this has not been
improved since the early I96013 when the advantages of the  float
process  became  apparent,  production is continuous seven days a
week.

process Water and Waste Water

Process water is used in  the  batch,  grinding,  polishing,  and
washing operations.  Approximately 42 I/metric ton (10/short ton)
of  water  are  added  to the raw materials for dust suppression.
This water is  evaporated  in  the  melting  tank.   waste  water
results  from  grinding, polishing, and washing the glass.  River
water is generally used for grinding and polishing, but  city  or
treated water is required for final washing and rinsing.

Grinding-*

Grinding  is the first step in the process to transform the rough
glass sheet into the finished plate-glass product.  A sand slurry
is used  in  conjunction  with  large  iron  grinding  wheels  to
actually grind down the glass surface.  Relatively coarse sand is
used  initially,  with progressively finer sand used as the glass
proceeds down the grinding line.  Sand slurry is recycled from  a
gravity  classifier.   All of the return from the grinders enters
one end of the classifier, the sand particles settle according to
size, and the waste water overflows at the other end.  The grind-
ing slurry is drawn from progressive segments of  the  bottom  of
the  tank.   Sand  classification is regulated by the velocity of
water passing through the tank and  is  controlled  by  both  the
slurry  drawoff  rate and the tank overflow.  Particles too small
to settle are removed in the overflow.  This waste  water  stream
is  very high in suspended solids consisting of fine sand, glass,
and iron particles.  About 87% of the flat glass waste  water  is
contributed by the grinding process.

Pollshinq-

Polishing  is  similar  to grinding except that smaller particles
are used.  Rouge (ferric oxide)  has generally been  used  as  the
polishing  medium,  but  at  least one company uses cerium oxide.
Neither grinding medium has an apparent advantage in terms of raw
waste water characteristics.  Felt pads are  used  to  apply  the
                             38

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      WATER
42 L/METRIC TON
(10GAL/SHORTTON)
RAW MATERIAL STORAGE
       MIXING
  COOLING WATER
  RIVER WATER
  RIVER WATER
    WATER
                                 MELTING
                               FORMING ROLLS
                                 ANNEALING
                                 CUTTING
      GRINDING
                                POLISHING
      WASHING
                                INSPECTION
                                 CUTTING
                                PACKAGING
                                 STORAGE
                                 COOLING WATER
                                      ..  KG-CAL_.
                               .539 X106 METRIC TON

                                      ft    BTU	
                               d.94X10b SHORT TON)
   WASTEWATER
 39,900 L/METRIC TON
(9,570 GAL/SHORT TON)
       87%

     WASTEWATER
  4,590 L/METRIC TON
 (1,100 GAL/SHORT TON)
       10%


     WASTEWATER
  1,380 L/METRIC TON
  (330 GAL/SHORT TON)
         3%
                                CONSUMER
                                FIGURE 7

                    PLATE  GLASS  MANUFACTURING
                              39

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polishing  medium to the" glass surface and, therefore, contribute
some organic matter to the waste  water  stream.   The  glass  is
ground first on one side and then on the other.  A bedding medium
is  required  to  evenly  support the glass.  Plaster of paris is
traditionally used  for  bedding;  however,  proprietary  methods
using  a  reusable  medium  have  been  developed  for  the newer
polishing lines.  Polishing contributes about 10%  of  the  plate
glass  waste water volume.  The major constituents include, rouge
or cerium oxide, glass particles, felt, and  calcium  sulfate  if
plaster of paris bedding is used.

Washing-

The residue resulting from grinding and polishing is removed by a
series  of  washing steps.  River water is generally used for the
first rinse, followed by an acid wash and a  final  rinsing  with
city  water.  The city water rinse may be followed by a deionized
water rinse,  washing contributes about 3%  of  the  plate  glass
waste  water  volume.   The  water  is clean as compared with the
grinding and polishing waste water.  The  initial  wash  contains
significant  suspended  solids, but the final wash is very clean.
Acid carry-over is quickly neutralized by the other waste streams
which tend to be basic.

Waste Water Volume and Characteristics

Some typical characteristics for the combined waste water  stream
are  listed  in  Table 5.  In all cases except for pH, the values
listed are the quantities added to the water as a result  of  the
plate  glass  process,  and  concentrations in the influent water
have been subtracted.

Flow—A variable volume of process water is used for plate  glass
manufacturing.   Flows  range  from 14,600 to 45,900 I/metric ton
(3,500 to 11,000 gal/short ton) or 4,920 to 18,200 cu m/day  (1.3
to  4.8  mgd]I.   The  typical flow is 45,900 I/metric ton (11,000
gal/short ton).  Water usage is related to the type  and  age  of
the  equipment  used,  with the highest water usage at the oldest
plants.  At plants built before water conservation and  pollution
control  were  widely  practiced, open channels were provided for
flushing away any wastes or spillage.  Large quantities of  water
are   necessary   to  maintain  sufficient  velocity  to  prevent
settling.  Extensive in-piant modifications will be  required  in
these plants to significantly reduce water usage.

Suspended solids—suspended solids are the major waste water con*
stituents  resulting from plate glass manufacture.  The available
data  shows  a  wide  variation  in   concentration,   but   good
correlation  in  terms  of  pounds  per  ton.   Approximately 690
kg/metric ton  (1,375  Ib/short  ton)  of  suspended  solids  are
discharged.   The  major  waste  water  source  is  the  grinding
operation, with lesser quantities contributed  by  polishing  and
washing.
                             40

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                                            TABLE 5
                                      RAW WASTEWATER (a)
                               PLATE GLASS MABUFACTURIEG PROCESS
Flow

pH

Temperature (b)

Suspended Solids

COD (b)

Dissolved Solids (b)
1*5,900  I/metric ton
2.8 C

690

It.6

8.0
kg/metric ton

kg/metric ton

kg/metric ton
11,000 gal/short ton



6 F

 1,375 Ib/short ton

9.2    Ib/short ton

16.1   Ib/short ton
15,000  mg/1

100     mg/1

175     mg/1
 (a)  Represents typical plate glass process vastewater prior to treatment.
     Absolute value given for pH, increase over plant influent level given
     for other parameters.
 (b)  Indication of approximate level only; insufficient data are available
     to define actual level.

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Other  parameters—Limited  information is available on other raw
water parameters.  Although sufficient information is not  avail-
able  to definitely establish the dissolved solids, BOD, COD, and
temperature levels, the data indicate these are insignificant  as
compared  with  suspended  solids.   Detergents are not used and,
therefore, no increase in phosphorus should  occur.   While  some
lubricating  oil dripping can be expected from the process equip--
ment, it cannot be detected in the large volume of waste water.

Discussion—Plate glass manufacturing is generally  a  continuous
operation  (24  hr/day  7  day/week),  and the waste water flows,
therefore, are relatively constant.  Polishing is done only  part
of the time in some plants, and the suspended solids loadings are
lower  when  polishing is not on line but the waste water flow is
not substantially reduced.  Waste water flows and characteristics
are also not significantly different during start-up or shutdown.
The plate furnace is drained every three to five  years  for  re-
building.   At this time, the glass is drained into a quench tank
and cooled with water.  Generally the quench water evaporates and
no  discharge  occurs.   No  toxic  materials  are  known  to  be
contained  in  waste  water  from  the  plate glass manufacturing
process.
In the plate glass manufacturing process, cooling  water  is  re-
quired  for  the  melting  tank forming rolls, annealing lehr and
compressors.  Two of the three plate glass plants in  the  United
States  reported  heat-rejection  data.  They are 311,000 kg-cal/
metric ton  (1,120,000 Btu/short ton)   and  766,000  kg-cal/metric
ton  (2,760,000  Btu/short  ton).    The wide variation in the two
values cannot be explained.  The larger value  is  probably  more
representative of actual plate glass heat rejection requirements.

FLOAT GLASS MANUFACTURING

The  float  process  may  be considered the replacement for plate
glass manufacturing.  Float  glass  production  is  substantially
less  expensive  and  process waste water has all but been elimi-
nated.  The major process steps and points  of  water  usage  are
illustrated in Figure 8.  The manufacturing process is more fully
explained in Section IV.

The  typical  float glass plant may be located in any part of the
country and has been built since 1960.   Both  float  and  mirror
washing  are practiced so that flows are approximately 30% higher
than if float washing alone is practiced.   Float  production  is
continuous  seven  days a week, but the mirror washer is operated
only as required.
                               42

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       WATER
  42 L/ METRIC TON
  (10 GAL/ SHORT TON)
                *
RAW MATERIAL STORAGE
       MIXING
COOLING WATER
                                MELTING
                               FLOAT BATH
                                                     „ COOLING WATER
                                                            ,  KG-CAL
                                                      .475 X106 METRIC TON
                                                             fi   BTU
                                                      (1.71 X 10b SHORT TON)
                               ANNEALING
                               INSPECTION
                                CUTTING
WATER
                                WASHING
                                 R.NSING
                             WASTE WATER
                               L/METRIC TON
                            (33 GAL/SHORT TON)
                               PACKAGING
                                STORAGE
                  CONSUMER
                                       FABRICATION
                             FIGURE 8
                 FLOAT GLASS  MANUFACTURING
                               43

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Process Wate^r and Waste Water

Process water is used in the batch and in some cases for washing.
Approximately 42 I/metric ton (10 gal/short  ton)  of  water  are
added  to  the raw materials for dust suppression.  This water is
evaporated in the melting tank.  Some plants wash the glass prior
to packing, and this constitutes the only waste water stream  for
this subcategory.

Hashing-

Sulfur  dioxide  is  sprayed  on the underside of the glass sheet
soon after forming to develop a protective coating.  Sodium  sul-
fate  is formed which, in high enough quantity, will show up as a
visible film on the glass which may be removed by washing.

Some plants wash as part of the float process and others do  not.
Generally,  where  they  do not, the glass is to be fabricated in
the same facility, and washing is the first step in the  fabrica-
tion  process.  Glass to be used for mirror manufacture is always
washed in a special washer not directly connected  to  the  float
line.   The  available  data  do  not distinguish between regular
washing and mirror washing, so both types are  considered  to  be
part  of  the  float  process  in this report.  The mirror washer
effluent is probably of higher quality than the float  washwater,
but the differences are not significant for this study.

Two  basic  types of washing systems are used.  Most plants pres-
ently use a one- or two-stage wash of city water quality followed
by a deionized water rinse.  The water is heated to 52-65°C (125-
160° F) to prevent glass breakage and to enhance  dissolution  of
the  soluble  film.   Maximum recycle is practiced, with blowdcwn
governed by dissolved solids buildup.  This system is typical  of
the industry.

An  older  three-stage  system  using detergents is still used at
some plants.  The first stage is a recycled detergent  wash  fol-
lowed  by  a  recycled city-water rinse and a recycled deionized-
water rinse.  Blowdown is governed by dissolved  solids  and  de-
tergent buildup.

Waste Water volume and characteristics

Some  typical  characteristics  of float-glass washwater blowdown
are listed in Table 6.  In all cases except for  pH,  the  values
listed  are  the quantities added to the water as a result of the
float glass process, and concentrations  in  the  influent  water
have been subtracted.

Flow—The  volume of washwater discharge is influenced by make-up
water characteristics and  mirror  washing  requirements.   Flows
range  from 88 to 138 I/metric ton (21 to 33 gal/short ton) or 34
to 136 cu m/day  (0.009 to 0.036 mgd), with  the  highest  volumes
recorded  for  plants that are washing mirror glass.  The typical
                              44

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Flow

pH

Temperature ("b)

Suspended Solids

Oil

COD

BOD

Phosphorus

Dissolved Solids
                                            TABLE 6
                                      RAW WASTEWATER  (a)
                               FLOAT GLASS MANUFACTURING PROCESS
138

8

37 C

2

• T

2

.25

(c)
1/metric ton
g/metric ton

g/metric ton

g/metric ton

g/metric ton



g/metric ton
33     gal/ton



98 F

.OOUl  Ib/short ton

.OOlfc  It/short ton

.00*0.  l"b/short ton

.0005  It/short ton



.028   Xb/short ton
15
5
15
2
mg/1
mg/1
mg/1
mg/1
                                                       100
 (a)  Representative of typical float glass process waste-water.  Absolute  value  given for
     pH and temperature, increase over plant influent level  given for  other parameters.

 ("b)  Indication of approximate level only; insufficient  data is available to  define
     actual level.
mg/1
 (c)  Wo information is available on wastewater containing phosphorus.

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flow is 138 I/metric ton  (33 gal/ton) .  The volume of waste water
discharged depends upon the dissolved-solids content of the make-
up water.  Slowdown rates are manually adjusted and are generally
held constant even though the square meters of glass  washed  may
vary  considerably.  The flow is set so that acceptable dissolved
solids concentrations are maintained at the highest washing rate.
Dissolved solids in the wash prior to  the  deionized  rinse  are
generally limited to 300 to 400 mg/1.

Waste  water  parameters—Slowdown  from  the  float washer is of
fairly high quality, as can be  seen  from  Table  6.   The  most
significant  increase  of 14 g/metric ton (0.028 Ib/short ton) or
100 mg/1 is noted for dissolved solids.  COD and suspended solids
show increases of only 2  g/metric  ton  (0.0041  Ib/short  ton).
Trace  quantities of BOD and oil are also present.  The available
data indicate a pH range of 7.4-8.2 with a typical pH of 8.  Only
one temperature reading was available, this gives  an  indication
of the water temperature, but should not be taken as typical.  No
information  was  available  on  the  phosphorus content of float
washer effluent where detergents are used, but the use of  deter-
gent  is  not  typical.  Deionizer regeneration is not considered
process waste water and,  therefore,  was  not  included  in  the
character!zation.

Discussion—Process  waste water from the float subcategory is of
fairly high quality and is disposed of only because of  the  dis-
solved  solids  concentration.  There is no significant change in
waste water characteristics during  start-up  or  shutdown.   The
float furnace is drained every 3 to 5 years for cleaning.  Molten
glass  is  drained  into  a  quench  tank and cooled with a water
spray.  The cooling water evaporates and no discharge occurs.

Cooling

In the float glass manufacturing process, cooling  water  is  re-
quired  for  the melting tank, float bath, annealing lehr and the
compressors.  Average heat rejection is 475,000 kg-cal/metric ton
(1,710,000 Btu/short ton) removed from the melting  tank  with  a
range  of  400,000 kg-cal/metric ton (1,440,000 Btu/short ton) to
561,000 kg-cal/metric ton (2,020,000 Btu/short ton).

SOLID TEMPERED AUTOMOTIVE GLASS FABRICATION

Solid tempered automotive fabrication  is  the  fabrication  from
glass   blanks   of  automobile  backlights  (back  windows)   and
sidelights (side windows).  The major process steps and points of
water usage are illustrated in Figure 9.  A detailed  description
of the manufacturing process is given in Section IV.

The typical solid tempered automotive glass fabrication plant may
be  located in any part of the country and uses process equipment
that  has  been  modified  within  the  last  10  to  15   years.
Production schedules are variable, but in many cases the plant is
operated five or six days a week for 24 hours a day.
                               46

-------
                                                              MAKE UP
                         TEMPLATE CUTTING
   WATER
                                         RECIRCULATION
                                          SETTING TANKS
NEGLIGIBLE
 AMOUNT
 FOR DUST
 CONTROL
SEAMING
      WASTEWATER
                                                  COOLING
EDGE GRINDING
                                                  SOLUTION
                                    COOLING
                                             tt
                                    SOLUTION
                                             DRILLING
                                                WATER
                             WASHING
  COOLING WATER
  SOLIDS
  TO LAND
  DISPOSAL


WATER
                                               WASTEWATER
                                                20L/SQ M
                                             (490 GAL/1000 SOFT)
                                                   41%
                             BENDING
                             TEMPERING
                                                 WASTEWATER
                                                 28.9  L/SQ M
                                              (710 GAL/ 1000 SQ FT)
                                                     59%
                                                    COOLING WATER
                                                  (DATA NOT AVAILABLE)
             AIR COOLING
                             QUENCHING
                                                            WATER
                                                           ^ WASTEWATER
                                                              3.1 L / SO M
                                                           ( 77 GAL /1000 SO FT)
                                                             NOT TYPICAL
                           INSPECTION
                            PACKAGING
                            STORAGE
                             CONSUMER
                              FIGURE  9
    SOLID  TEMPERED  AUTOMOTIVE  GLASS  FABRICATION
                           47

-------
Process Water and Waste Water

Water  is  used  in  solid  tempered  automotive  fabrication for
seaming, grinding, drilling,  quenching,  cooling,  and  washing.
The washwater is the major source of contaminated waste water.

Seaming-

Seaming  is  a  light  grinding  to  remove  the  sharp  edges on
backlights.  In some cases, a fine spray of water is used to hold
down the dust.

ffdge Grinding-

Edge grinding is used to form the  smooth  rounded  edge  on  the
exposed  surfaces  of sidelights.  An oil-water emulsion coolant-
solution is used which  also  serves  to  flush  away  the  glass
particles.   All  plants  recycle  the  coolant through a gravity
sedimentation chamber where the glass particles  settle  and  are
removed  along  with  free floating oil and scum.  The coolant is
continuously recycled and the only blowdown from  the  system  is
the  carry-over that remains on the glass.  In the typical plant,
the settled sludge and skimmings are collected  for  disposal  as
landfill;  a  few  plants,  however,  discharge this waste to the
waste water system.  About 11.2 g/sq m (2.3 lb/1000 sq ft)  of dry
sludge is produced.

Drilling-

Holes are drilled in sidelights for window handles and  brackets.
Water is used in this process to cool the drill and to flush away
the glass particles.  The typical flow is 20 1/sq m (U90 gal/1000
sq ft) .

Washincf-

Washing   is  required  to  remove  residual  coolant  and  glass
particles.  One or two washing  steps  may  be  used  before  the
bending  furnace, depending on the plant set up.  Where the plant
is set up on a production-line basis,  the  glass  goes  directly
from edge grinding through drilling and washing to tempering, and
only  one  washer  is  used.   The edging or drilling and seaming
lines may also operate independently of the  tempering  line,  in
which  case  washing  occurs  following  drilling and seaming and
again before tempering.  More water  is  used  in  the  two-stage
process,   but  the  pollutant  loadings  are  not  significantly
different.

Both once-through and recycling washers are  used,  two  or  more
stages  may  be  used with each recycling from its own reservoir.
Make-up water is added to the last stage and waste water is  dis-
charged  from  the  first  stage.  The recycle systems reduce the
water usage, but the quantity of waste products is  not  reduced.
The  washwater  is heated to accelerate removal of oily residues.
                             48

-------
Recycling is limited by the build-up of oil and suspended  solids.
A typical plant uses one or two wash steps, with some  recycling.
The typical flow is 28.9 1/sq m (710 gal/1000 sq ft).

Quenching^-

Rapid  cooling is required by the tempering process.  Air  cooling
is typical, but quenching  is  also  done  with  a   water  spray.
Quench  water  is  considered  a  process waste because the water
comes in direct contact with the glass.   Very  little,  if  any,
contaminants  are  picked up.  The only apparent benefit of water
quenching is that less space is required than  for   air  cooling.
About  3,1  1/sq m  (77 gal/1000 sq ft)  is used where quenching is
employed.

Waste_Hater Volume apd Charac.te.risties

Some  typical  characteristics  of  the  combined    waste   water
resulting  from  solid tempered automotive fabrication are listed
in Table 7.  In all cases except for pH, the  values  listed  are
the  quantities  added to the water as a result of solid tempered
automotive fabrication.  The background  level  in   the  influent
water  has  been subtracted.  The significant parameters are BOD,
suspended solids, and oil.

Flow—Process waste water flows vary significantly,  ranging  from
40.7-105  1/sq  m   (1000  to 2,600 gal/1000 sq ft)  or 492-1551 cu
m/day (0.13 to 0.41 mgd).  The typical flow is considered  to  be
49  1/sq  m  (1200  gal/1000  sq ft).  As stated above, the waste
water flow rates are influenced both by  the  number  of   washing
step s   employed   and  by  recycling.   The  high   f1ow-rate  i s
indicative of a plant which does not recycle water.

Suspended solids—Suspended solids are added to the  waste  stream
in  the form of glass particles resulting from seaming, grinding,
and drilling.  A typical plant generates 4,9 g/sq m  (1 lb/1000 sq
ft).  Some decrease in suspended solids loading may  be  expected
if  dry  seaming is practiced, but a quantitative estimate of the
reduction is not available.

Oil—Almost all the oil is contributed by the  grinding  solution
carry-over,  with trace quantities added by miscellaneous machine
lubricants.  Typical plant waste water contains 0.64 g/sq m (0.13
lb/1000 sq ft).

Biochemical Oxygen Demand—A small quantity of BOD is contributed
to the waste water by the oil in the coolant solution  carry-over
and  to a much lesser extent by traces of oil entering the waste-
water stream as a result of machinery lubrication.    The  typical
raw waste water loading is 0.73 g/sq m (0.15 lb/1000 sq ft).

Other  parameters—Some information is also available on pH, tem-
perature, COD,  and dissolved solids.   Limited data are  available
for temperature and COD, but 8°C (17°F)  and 1.22 g/sq m (0.25 lb/
                              49

-------
                                                      TABLE 7
                                                RAW WASTEWATER (a)
                                    SOLID TEMPERED AUTOMOTIVE GLASS FABRICATION
01
o
Flow
pE
Temperature (t )
Suspended Solids
Oil
COD (t)
BOD
Dissolved Solids
1*9 1/sq m 1200
7
8 C 17 F
^•9 S/sq m 1
.61* g/sq m .13
1.22 g/sq m .25
.73 g/sq m .15
4.9 g/sq m 1
gal/1000 sq ft


It/1000 sq ft
It/1000 sq ft
It/1000 sq ft
It/1000 sq ft
It/1000 sq ft



100 mg/1
13 mg/1
25 mg/1
15 mg/1
100 mg/1
          (a)  Representative of typical solid tempered automotive process "waste-water.  Atsolute
               value given for pH3 increase over plant influent level given for other parameters,

          (t)  Indication of approximate level only; insufficient data is avallatle to define
               actual level.

-------
1000  sq ft) are indicative of the increases to be expected.  A pH
of  nearly 7 was recorded in all cases, indicating that pH is not
a problem in solid tempered automotive  glass  fabrication-   The
dissolved  solids  increase  of  4.9  g/sq m  (1 lb/1000 sq ft) is
higher than was expected.  Water treatment regenerants and boiler
blowdcwn  (which are combined with the process waste water  stream
for   much  of the sample data) are assumed to have contributed at
least in part to the dissolved solids increase.

Discussion—-No significant variations in waste  water  volume  or
characteristics  are  experienced  during plant start-up or  shut-
down, and there are no known toxic materials in waste water  from
the solid tempered automotive glass manufacturing process.

Cooling

Cooling water is required at some solid tempered automotive  glass
plants  for the tempering hearth and quenching.  Although no data
is available, heat rejection for these operations can be expected
to be low with respect to the other subcategories.

WINDSHIELD FABRICATION

Windshield fabrication is the manufacturing  of  laminated   wind-
shields  from glass blanks and vinyl plastic.  Oil resulting from
oil autoclaving is the major constituent  in  this  waste  water.
The major process steps and points of water usage are illustrated
in  Figure  10.   A  detailed  description  of  the manufacturing
process is given in Section IV.

The typical windshield fabrication plant may be  located  in any
part of the country and uses oil autoclaves.  Air autoclaves have
been  installed  at some new plants, but oil autoclaves are  still
used  for  90%  of  the  windshields  produced.   The  production
schedule  is variable and ranges from an eight hour five-day week
to a  24 hour six-day week.


Process Water and Waste Water

Water is used in windshield fabrication for cooling, seaming, and
washing.  Three or four washes are required when  oil  autoclaves
are   used.    Initial,  vinyl,  and  post-lamination  washes  are
required  in  all  cases.   The  prelamination  wash   has   been
eliminated by some plants.

Seaming-

Wet  or  dry  seaming  may  be used in the windshield fabrication
process.  With wet seaming,  a small volume of water is  used  for
dust  control  and  to  flush  away the glass particles produced.
About 8.2 1/sq m (200 gal/1000 sq ft)  of finished windshields  is
used.

-------
                            TEMPLATE CUTTING
        WATER
                               SEAMING
        WATER
                                WASHING
                                 RINSING
    WATER
  VINYL WASH
                               BENDING
                            PRELAMINATION
                             WASH & RINSE
           VINYL INSERTS
   WASTEWATER
    2B.SL/SQ M
(700 GAL/1000 SO FT)
      16%
                        VINYL ASSEMBLY TACKING
COOLING
            RECYCLED OIL
          WATER
AUTOCLAVING
  DRAINING
                   .RECYCLED
                      OIL
             WATER
SOLIDS TO
   LAND
 DISPOSAL
       WASTE WATER
    NEGLIGIBLE AMOUNT
                            FINAL WASH & RINSE
                                PACKAGING
                                STORAGE
                              CONSUMER
                               FIGURE 10
                     WINDSHIELD   FABRICATION
                                                           WASTEWATER
                                                            8.2L/SQM
                                                         (200 GAL/1000 SQ FT)
                                                                5%
                             WASTEWATER
                             81.5 L/SQ M
                          (2000GAL/1000SQ FT)
                                47%

                          PARTING MATERIAL
                            APPLICATION
                                                           WASTEWATER
                                                            16.3 L/SQ M
                                                        (400 GAL/1000 SO FT)
                                                               9%
                                                           COOLING WATER
                                                       49.3 X103 KG-CAL/SQM
                                                        (18.2X103BTU/SQ FT)
                                                           WASTEWATER
                                                           40.7 L/SO M
                                                        (1000 GAL/1000 SOFT)
                                                               23%
                             52

-------
Initial Wash-

The  first wash occurs early in the manufacturing process, follow-
ing  cutting  and seaming.  Traces of cutting oil, residual glass
particles, and any dust which may have accumulated on  the  glass
while  in  storage  is  removed.   Only water, which is generally
heated, is used.  No detergents or other cleaning  compounds  are
required.

Various  types  of washers are used,  in some cases, once-through
washwater is discharged directly  to  the  sewer.   Newer  plants
generally use recycling washers to reduce water usage.  The waste
water flows vary from 28.5 to 138 1/sq m (700 to 3UOO gal/1000 sq
ft)  of  finished  windshields.   The typical flow is 81.5 1/sq m
(2000 gal/1000 sq ft) .

Prelamination Wash-

The  two pieces of glass used to form a windshield are bent as one
unit, and a parting material is used to prevent  the  two  pieces
from  fusing during the bending process.  The parting material is
usually washed before the vinyl sheet is inserted,  but  in  some
cases  a  material  is  used  that does not require washing.  The
exact nature of the parting materials used  and  the  details  of
their  application  and removal are considered proprietary by the
industry.

The prelamination washer also serves to clean the  glass  surface
of   any  dirt  or  spots  since  they cannot be removed following
lamination.  A three-stage washer is  usually  used.   The  first
stage  is  a  detergent wash followed by a city-water rinse and a
final demineralized-water rinse.  Deionized rinse  water  is  the
only makeup to the system.  It is recycled through the stages and
discharged  as  blowdown from the detergent wash.  All stages are
heated.  Water usage is about 16.3 1/sq m (400 gal/1000 sq ft)  of
windshields produced.  The limited data available indicate a  hot
waste  water with relatively high phosphorus, moderate dissolved-
solids, and low organic and suspended solids increases.

Vinyl Wash-

The plastic used for laminating is shipped from the  manufacturer
in  rolls.   Sodium  bicarbonate is used as a parting material to
keep the plastic from sticking and is removed in a two- or three-
stage washer.  The three-stage system uses two city-water  washes
in  series  followed  by  a deionized-water rinse.  The two-stage
system is used where relatively  low  dissolved-solids  water  is
available  and  consists  of  two  city-water  rinses  in series.
Highly variable quantities of water are used for washing plastic,
ranging from 12.2 to 285 1/sq m (300 to  7000  gal/1000  sq  ft).
The  typical  flow rate is 28.5 1/sq m (700 gal/1000 sq ft).  The
waste water is high in dissolved solids  because  of  the  sodium
bicarbonate.   The  data  also  indicate a COD of 100 mg/1 or 2.8
                               53

-------
g/sq m  (0.58 lb/1000 sq ft) based on the typical flow.
COD is unexpected and has not been explained.

Post-Lamination Wash-*
The  high
Residual  oil  from  the  laminating  autoclaves  is removed in a
series washing operation.  Two basic systems are employed in  the
industry.   In  one  case  only  washing is accomplished.  In the
second case, the washing is done in two stages with  dry  seaming
in  tetween  washing  steps.  The waste water characteristics are
similar for both systems.  For the purposes of this report,  both
systems will be grouped and discussed as one process.

Washwater for each stage is recycled out of a reservoir.  In some
cases,  flows are countercurrent with blowdown from the following
stage serving as makeup for the preceding stage.

The old method of post-lamination washing,  still  used  at  some
plants, is to use a detergent wash as the first stage followed by
two city-water rinses and possibly a final deionized-water rinse.
Large  quantities of detergent are required with this system, and
very oily emulsified waste water is produced.

Using a hot-water rinse before the detergent wash has been  found
to  cut detergent usage by up to 95S&.  Most of the oil is removed
by the hot water, and proportionately less detergent is  required
to  emulsify the residual oil.  Although the same quantity of oil
remains in the waste water stream, the majority is free  oil  and
is more readily removed than emulsified oil.

The waste water flows are the same for both methods.  The typical
post-lamination  washer flow is 40.7 1/sq m  (1000 gal/1000 sq ft)
of windshields produced.  Waste water  characteristics  are  also
similar for both methods, except higher phosphorus concentrations
resulting  from higher detergent usage are expected where an ini-
tial detergent wash is used.

Oil Separation System-

Small amounts of water are picked up by the  autoclave  oil  from
condensation,  cooling  water  leaks, and other sources.  The oil
and water separate in the oil storage tanks and the water is  re-
moved  to  a  second  tank where further gravity separation takes
place.  The oil is recycled to the autoclaves and  the  water  is
either  discharged  to  the  sewer  or to the autoclave washwater
treatment system.  The stream accounts for only one to  two  per-
cent of the total waste water flow.
                          i
Waste Water Volume and Characteristics

Some  typical  characteristics of the combined waste water stream
resulting from windshield fabrication are listed in Table 8.   In
all  cases  except  for  pH, the values listed are the quantities
added to the water as a result of  windshield  fabrication.   The
                               54

-------
                                                          TABLE  8
                                                    RAW WASTEWATER  (a)  .
                                        WINDSHIELD FABRICATION USING  OIL AUTOCLAVES
4J1
Flow

PH

Temperature

Suspended Solids,

Oil

COD

BOD

Total Phosphorus
175
7-8
18.9 c
U.U.
298
298
5.9
• 98
1/sq m


g/sq m
g/sq m
g/sq m
g/sq m
g/sq m
4300

UO F
.9
61
61
1.2
.2
                                                                        gal/1000  sq ft
Ib/1000 sq. ft

113/1000 sq ft

lb/1000 sq ft

lb/1000 sq ft

lb/1000 sq ft
25

1TOO

1700

33

5.6
mg/1

mg/1

mg/1

mg/1

mg/1
               (a)  Representative  of typical process wastewater from the fabrication of windshields
                   using oil  autoclaves.   Absolute  values  are  listed for pH;  the increase  over plant
                   influent level  is given for  other parameters.

-------
influent  water  background  levels  have been subtracted.  These
data apply to a plant where an initial hot-water  rinse  is  used
for  the  post-lamination  wash.  NO information is available for
plants using an initial detergent wash.

Flow—-Waste water flow rates from plants  considered  typical  of
the  windshield  fabrication process vary from 52.9 to 492 1/sq m
(1300 to 12,100 gal/1000 sq ft) of  windshields  produced.   This
corresponds  to  454  to  2195  cu m/day (0.12 to 0.58 mgd) .  The
variability is due to the type of washers used  (once-through  as
opposed  to recycling) and to the dissolved-solids content of the
plant water.  Less recycling  can  be  practiced  where  influent
dissolved  solids are high.  The typical flow is 175 1/sq m  (4300
gal/1000 sq ft).

Suspended solids—Suspended solids are contributed to  windshield
fabrication  waste  water as a result of seaming.  Carry-over re-
sults, even when dry  seaming  is  used.   The  data  indicate  a
typical  reported  value  of 137 g/sq m  (28 lb/1000 sq ft) or 780
mg/1.  This figure is much  higher  than  the  actual  suspended-
solids  level because of oil interference since free oil tends to
collect on the filter used in the suspended solids determination,
causing high readings.  The actual typical suspended  solids  are
estimated at 4.4 g/sq m (0.9 lb/1000 sq ft)  or 25 mg/1.

pil~-Almost all the oil is contributed by the laminating process,
with  trace  amounts  resulting  from machinery lubrication.  The
typical loading is 298 g/sq m  (61 lb/1000 sq ft).

Chemical Oxygen Demand—A significant COD is noted as a result of
the high oil content from the post-lamination wash.   Almost  the
entire loading of 298 g/sq m (61 lb/1000 sq ft)  may be attributed
to  oil.  As indicated above, some COD is also contributed by the
vinyl washwater.

pH—The pH for all of the plants  for  which  data  was  received
ranged  between  7  and  8.  Sodium bicarbonate, removed from the
vinyl, is the only constituent added which would be  expected  to
significantly  affect pH.  Sufficient dilution is provided by the
other waste waters so that little effect is noted.

Phosphorus—Phosphorus results from detergents used in  the  pre-
assemfcly  and  post-lamination washes.  The available information
on phosphorus loading  shows  substantial  variation,  indicating
variable  detergent  usage.   No  basis is available for defining
phos phorus  or  detergent  1imitation s;  therefore,  the  typi cal
phosphorus  value  is  based  on  the plants with high phosphorus
loadings.  The typical value is 0,98 g/sq m (0.2 lb/1000 sq ft).

Other parameters—Limited information is  available  on  BOD  and
temperature  characteristics  for raw windshield-lamination waste
water.  The data indicate a  BOD  loading  of  5,9  g/sq  m  (1.2
lb/1000  sq  ft)  or 33 mg/1.  As with COD, the BOD can be attri-
buted to the  oily  waste  water  temperatures.   These  show  an
                              56

-------
average  discharge  temperature immediately following the process
of 38.9°C  (102°F) or 18.9°C. (40°F) over the influent temperature.
Sufficient data is not available to give  an  indication  of  the
dissolved-solids levels.

Discussion—No  significant  variations  in waste water volume or
characteristics are experienced during plant  start-up  or  shut-
down,  and there are no known toxic materials in waste water from
the windshield fabrication process.

Cooling

Cooling water is required for autoclave operations and  the  com-
pressors.   Data is available from two plants.  Values are 40,100
kg-cal/pq m (14,800 Btu/sq ft)  and  58,600  kg-cal/sq  m  (21,600
Btu/sq  ft)  of  fabricated  automotive  glass.   The average heat
rejection is 49,300 kg-cal/sq m (18,200 Btu/sq ft).
                              57

-------

-------
                            SECTION  VI

                 SELECTION  OF  POLLUTANT PARAMETERS

 Subcategories  causing  significant pollution  in   this   portion   of
 the   flat  glass  industry are  plate glass manufacturing,  solid
 tempered automotive, and windshield fabrication.  The  major  waste
 water constituents are the result of various types  of  grinding
 and   oil   autoclaving .   Less signif icant   dissolved- solids  are
 contributed by parting materials used at  several points in   these
 processes  for  glass or plastic separation.
The major parameters of pollutional significance for the combined
group of subcategories are:

         Total Suspended Solids  (TSS)

         Oil and Grease

         pH

         Total Phosphorus

Other  parameters contained in process waste waters from the flat
glass segment of the glass industry  are  BOD,  COD,  detergents,
temperature and dissolved solids.

The   above  parameters  do  not  occur  in  all  cases  for  all
subcategories, or may fce less significant in one subcategory than
in  another.   Table  9  lists  the  typical  concentrations   by
subcategory.   These are the only constituents known to be added.
On the basis  of  the  data  collected,  no  toxic  or  hazardous
substances are contained in these process waste waters.

TOTAL SUSPENDED, SOLIDS (TSS)

Suspended  solids  include  both organic and inorganic materials.
The inorganic components  include  sand,  silt,  and  clay.   The
organic  fraction  includes  such  materials as grease, oil, tar,
animal and vegetable fats, various  fibers,  sawdust,  hair,  and
various  materials  from  sewers.   These  solids  may settle out
rapidly and bottom deposits are often a mixture of  both  organic
and   inorganic  solids.    They  adversely  affect  fisheries  by
covering the bottom of the stream  or  lake  with  a  blanket  of
material that destroys the fish-food bottom fauna or the spawning
ground  of  fish.   Deposits  containing  organic  materials  may
deplete bottom oxygen  supplies  and  produce  hydrogen  sulfide,
carbon dioxide, methane,  and other noxious gases.

In  raw  water  sources  for  domestic  use,  state  and regional
agencies generally specify that suspended solids in streams shall
not te present in sufficient concentration to be objectionable or
                              59

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Ol
o
                                                        TABLE 9
                                        COHCENTRATIOU OF WASTEWATER PARAMETERS
                           PRIMARY FLAT GLASS MAHUFACTURIHG AUD. AUTOMOTIVE GLASS FABRICATION

                                                         TYPICAL RAW WASTEWATER COCTCEHTRATIOH  (a)
Suspended Solids, mg/1

Oil, mg/1

COD, mg/1

BOD, mg/1

pH

Total Phosphorus, mg/1

Temperature F

Dissolved Solids, mg/l(d)

Rolled
Glass

0)
-p
$
0)
-p
ra

m
w
0)
o
o
ft
o



Sheet
Glass

o
-p
I
0)
-p
CQ

to
in
0)
CJ
o
ft
o
fl


Plate
Glass
15,000
trace

100 (b)


Cc)

9


no increase

6(b)
175 (b)

Float
Glass
15
5

15


2

8


no increase

moderate (c)
100
Solid
Tempered Windshield
Automotive Fabrication
100 25
13 1,700

25 1,700


15 33

7 7-8


no increase 5

17 (b) 1*0 (b
100 lov(c
             (a)  Increase over "background concentration for all parameters except for pH.

             (t>)  Based on limited data, indication of typical value only.

             (c)  Insufficient data to define.

             (d)  In some cases, dissolved solids influenced by auxiliary wastes.

-------
 to  interfere  with normal  treatment processes.    Suspended   solids
 in   water  may interfere with many industrial processes,  and cause
 foaming  in boilers, or  encrustations  on  equipment  exposed  to
 water, especially as the  temperature rises.  Suspended solids  are
 undesirable  in  water  for  textile  industries; paper  and pulp;
 beverages;  dairy  products;  laundries;   dyeing;   photography;
 cooling  systems,  and  power  plants.   Suspended particles also
 serve  as   a   transport   mechanism  for  pesticides   and    other
 substances which are readily sorbed into or onto clay particles.

 Solids   may  be suspended in water for a time, and then  settle to
 the  ted  of   the  stream or  lake.   These  settleable   solids
 discharged with  man's wastes may be inert, slowly biodegradable
 materials,  or rapidly   decomposable   substances.    While  in
 suspension,   they  increase  the  turbidity  of the water,  reduce
 light penetration  and  impair  the  photosynthetic  activity  of
 aquatic  plants.

 Solids   in  suspension  are aesthetically displeasing.   When they
 settle to  form sludge deposits on the stream or  lake  bed,  they
 are  often  much  more  damaging  to  the life in water, and they
 retain the  capacity  to  displease  the  senses.   Solids,  when
 transformed  to  sludge   deposits,  may  do a variety of damaging
 things,  including blanketing the stream or lake bed  and  thereby
 destroying  the  living   spaces  for those benthic organisms that
 would otherwise occupy the  habitat.   When  of  an  organic and
 therefore  decomposable nature, solids use a portion or all  of the
 dissolved   oxygen  available in the area.  Organic materials also
 serve as a  seemingly inexhaustible food  source  for  sludgeworms
 and  associated organisms.

 Turbidity   is  principally  a  measure  of  the  light  absorbing
 properties  of  suspended solids.   It  is  frequently  used   as  a
 substitute  method  of  quickly  estimating  the  total suspended
 solids when the concentration is relatively low.

 Suspended solids  are  contained  at  various  concentrations  in
 plate,  float,  and automotive fabrication waste waters.   Typical
 raw  waste concentrations range from 15 mg/1 for float  to   15,000
 mg/1 for plate glass manufacturing.
Oil  and  grease  exhibit  an  oxygen  demand.  Oil emulsions may
adhere to the gills of fish or coat and destroy  algae  or  other
plankton.  Deposition of oil in the bottom sediments can serve to
inhibit  normal  benthic  growths,  thus interrupting the aquatic
food chain.  Soluble and emulsified material ingested by fish may
taint the flavor of the fish flesh.  Water soluble components may
exert toxic action on fish.  Floating  oil  may  reduce  the  re-
aeration  of the water surface and in conjunction with emulsified
oil  may  interfere   with   photosynthesis.    Water   insoluble
components  damage  the  plumage  and  costs of water animals and
fowls.  Oil and grease in a water can result in the formation  of

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objectionable   surface  slicks  preventing  the  full  aesthetic
enjoyment of the water.
Oil spills can damage the surface of boats and  can
aesthetic characteristics of beaches and shorelines.
destroy  the
Oil  is  contributed  to  flat  glass waste waters as a result of
laminating,   edge   grinding,   and   miscellaneous    machinery
lubrication.   At least traces of oil appear in all process waste
water, but significant quantities are contained in solid tempered
automotive and  windshield  fabrication  wastes.   The  state  of
Illinois  limits oil discharge to 15 mg/1.  Public Health Service
Drinking Water Standards, by limiting carbon  chloroform  extract
(CCE)  to  0.2  mg/1,  allow  virtually  no  oil concentration in
drinking water.  Raw waste water  concentrations  in  this  study
range from traces resulting from machinery lubrication to 13 mg/1
for  solid  tempered  automotive  and  1700  mg/1  for windshield
fabrication.

pH,_ ACIDITY AND ALKALINITY

Acidity and alkalinity are reciprocal terms.  Acidity is produced
by substances  that  yield  hydrogen  ions  upon  hydrolysis  and
alkalinity  is  produced  by substarices that yield hydroxyl ions,
The terms "total acidity" and "total alkalinity" are  often  used
to  express  the  buffering  capacity  of a solution.  Acidity in
natural waters is caused by carbon dioxide, mineral acids, weakly
dissociated acids, and the salts of strong acids and weak  bases.
Alkalinity  is  caused  by  strong  bases and the salts of strong
alkalies and weak acids.

The term pH is a logarithmic expression of the  concentration  of
hydrogen  ions.   At  a  pH  of  7, the hydrogen and hydroxyl ion
concentrations are essentially equal and the  water  is  neutral.
Lower  pH  values  indicate  acidity while higher values indicate
alkalinity.   The  relationship  between  pH   and   acidity   or
alkalinity is not necessarily linear or direct.

Waters  with  a  pH  below  6.0  are  corrosive  to  water  works
structures, distribution lines, and household  plumbing  fixtures
and  can  thus  add  such constituents to drinking water as iron,
copper, zinc, cadmium and lead.  The hydrogen  ion  concentration
can  affect  the  "taste" of the water.  At a low pH water tastes
"sour".  The bactericidal effect of chlorine is weakened  as  the
pH  increases,  and  it  is advantages to keep the pH close to 7.
This is very significant for providing safe drinking water.

Extremes of pH or rapid pH changes can exert stream conditions or
kill aquatic life outright (ammonia is more lethal with a  higher
pH).   Dead  fish, associated algal blooms, and four stenches are
aesthetic liabilities of any  waterway.   Even  moderate  changes
from  "acceptable"  criteria limits of pH are deleterious to some
species.  The relative toxicity to aquatic life of many materials
is increased by changes in the water pH.  Metalocyanide complexes
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 can  increase  a thousand-fold  in  toxicity with  a  drop   of   1.5   pH
 units.    The  availability of  many  nutrient  substances  varies with
 the  alkalinity and  acidity.

 The  lacrimal  fluid  of  the human  eye has a pH of  approximately  7.0
 and  a deviation of  0.1 pH unit from the norm may  result   in  eye
 irritation  for  the   swimmer.   Appreciable irritation will  cause
 severe pain.

 Except for plate glass manufacturing, pH  is   not  a   significant
 pollutant in  the  flat  glass  industry.   pH  levels of  6-9  are
 generally considered acceptable, and these  are  readily  achieved
 in   all   the  other subcategories.  Plate glass  wastes tend  to be
 alkaline, and in some  plants  acid  treatment is used to reduce  the
 pH to 9.

 PHOSPHORUS

 Phosphorus is contributed to  the windshield waste  water  stream
 and,  in  some  cases,  to  float  waste water through the use of
 detergents.  During the past  30  years,  a  formidable case  has
 developed for  the  belief   that  increasing  standing  crops of
 aquatic plant growths, which  often interfere with water uses  and
 are  nuisances  to  man,  frequently  are   caused  by  increasing
 supplies  of phosphorus.  Such phenomena  are   associated  with a
 condition  of  accelerated eutrophication or aging of  waters.   It
 is generally recognized that  phosphorus is  not the sole cause   of
 eutrophication,  but there is evidence to substantiate that  it is
 frequently the key element in all  of  the   elements  required   by
 fresh  water  plants and is generally present  in the least amount
 relative to need.  Therefore, an increase   in  phosphorus  allows
 use  of   other,  already  present,  nutrients  for plant growths.
 Phosphorus is usually  described, for this reason, as a "limiting
 factor".

 When a plant population is stimulated in production and attains a
 nuisance  status,  a   large  number of associated liabilities  are
 immediately apparent.   Dense  populations  of  pond   weeds  make
 swimming  dangerous.   Boating  and  water  skiing  and sometimes
 fishing may be eliminated because  of the mass  of vegetation  that
 serves  as  a  physical  impediment  to  such  activities.   Plant
 populations have been associated with  stunted  fish   populations
 and  with  poor  fishing.   Plant  nuisances   emit vile stenches,
 impart tastes and odors to water supplies, reduce the  efficiency
 of  industrial  and  municipal  water treatment, impair aesthetic
 beauty,  reduce  or  restrict  resort  trade,  lower   waterfront
 property  values,  cause skin rashes to man during water contact,
 and serve as a desired substrate and breeding ground   for  flies.
 Total phosphorus is also a measure of detergent usage.

 OTHE PT.PARAMETERS

As   mentioned  above,   there  are  other  parameters  which   are
 contained in process waste waters in  the  flat  glass  industry:
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BOD,  COD,  detergents,  temperature, and dissolved solids.  Both
BOD and COD are intended to be measures of the organic content of
a water or waste water, and are described below..   In  the  flat
glass  industry,  BOD  and  COD are contributed mainly by oil and
grease, and suspended solids.  However, soluble BOD and  COD  are
already  present  in  many  cases  in  water  used  in flat glass
processes.   The  concentrations  are  often   significant   when
compared  to  the COD and BOD added by the processes.  Therefore,
these measurements are not appropriate for pollution  control  in
the  flat  glass  industry.   The  organic  matter  added  by the
processes is adequately described by  the  oil  and  grease,  and
suspended solids parameters.

As  described  below,  dissolved  solids  are  added  by  various
processes but the technology  to  control  these  substances  are
extremely  expensive  and  complex.   Moreover,  the solid wastes
generated are difficult to dispose of and often pose more  of  an
environmental  problem  than  if  they  remained in process waste
waters.  The control technology is  fully  described  in  section
VII.

                       (COD)
COD  is a measure of the oxygen consuming capabilities of organic
matter.  It measures the amount of  organic  and  some  inorganic
pollutants under a carefully controlled direct chemical oxidation
by  a dichromate-sulfuric acid reagent.  COD is a much more rapid
measure of oxygen demand  than  BOD£,  and  is  potentially  very
useful.   However, it does not have the same significance, and at
the present time cannot be substituted for BOD5 because  COD:BOD5
ratios vary with the types of wastes.         "

COD  provides  a  rapid determination of the waste strength.  Its
measurement  will  indicate  a   serious   plant   or   treatment
malfunction  long  before  the BODS can be run.  A given plant or
waste treatment system  usually has a relatively narrow range  of
COD: BOD 5   ratios,   if  the  waste  characteristics  are  fairly
constant, so experience permits a judgment to be made  concerning
plant operation from COD values.

Some  COD  is contributed by all of the process waste waters, and
the values range from 15 mg/1 for float glass to  1700  mg/1  for
the  typical windshield fabrication plant.  In most cases, COD is
a  direct  result  of  the  oil   concentration.    Because   BOD
concentrations are low, COD is a more accurate measure of organic
content for flat glass waste water.

BIQggEMlCAL OXYGEN DEMAND^ JBO
Biochemical  oxygen  demand  (BOD)   is  another measure of oxygen
demand.  The BOD does not in itself cause direct harm to a  water
system,  but  it  does exert an indirect effect by depressing the
oxygen content of the water.  Sewage and other organic  effluents
during  their  processes  of decomposition exert a BOD, which can
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 have a catastrophic effect on  the  ecosystem  by   depleting   the
 oxygen  supply.   Conditions  are reached frequently where  all of
 the oxygen is used and the continuing decay  process  causes   the
 production of noxious gases such as hydrogen sulfide and methane.
 Water  with  a  high  BOD  indicates  the presence  of decomposing
 organic matter and subsequent high bacterial counts that  degrade
 its quality and potential uses.

 If  a  high  BOD  is present, the quality of the water is usually
 visually degraded by the presence of  decomposing   materials   and
 algae  blooms  due  to the uptake of degraded materials that form
 the foodstuffs of the algal populations.  Dissolved oxygen  (DO)
 is   a   water   quality   constituent   that,   in   appropriate
 concentrations* is essential not only to  keep  organisms   living
 but   also  to  sustain  species  reproduction,  vigor,  and   the
 development of populations.  Organisms undergo stress at  reduced
 D.O.  concentrations  that make them less competitive and able to
 sustain  their  species  within  the  aquatic  environment.    For
 example,  reduced  DO concentrations have been shown to interfere
 with fish population through delayed hatching  of   eggs,  reduced
 size  and  vigor  of embryos, production of deformities in  young,
 interference with food digestion, acceleration of blood clotting,
 decreased tolerance to certain toxicants, reduced food efficiency
 and growth rate, and reduced maximum  sustained  swimming   speed.
 Fish food organisms are likewise affected adversely in conditions
 with  suppressed  DO.  Since all aerobic aquatic organisms  need a
 certain amount of oxygen,  the  consequences  of  total  lack  of
 dissolved  oxygen  due  to a high BOD can kill all  inhabitants of
 the affected area.

 At least trace concentrations of BOD are present in  all  of   the
 process  waste  streams.   Insignificant loadings occur for plate
 and float  glass  and  at  least  measurable  concentrations   are
 recorded   for   solid   tempered   automotive   and   windshield
 fabrication.  BOD is inferior to COD  as  a  measure  of  organic
 pollution, because of the low concentrations recorded in the flat
 glass  industry  and  the  absence of organic loading, except  for
 oil.

 TEMPERATURE


Temperature is one of the most important  and  influential  water
 quality  characteristics.   Temperature  determines those species
that  may  be  present;   it  activates  the  hatching  of  young,
regulates  their  activity,  and  stimulates  or suppresses their
growth and development;  it attracts, and may kill when the  water
becomes  too  hot  or becomes chilled too suddenly.  Colder water
 generally  suppresses  development.     warmer   water   generally
accelerates  activity and may be a primary cause of aquatic plant
nuisances when other environmental factors are suitable.

Temperature is a prime regulator of  natural processes within  the
water   environment.     It  governs   physiological  functions  in
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organisms and, acting directly or indirectly in combination  with
other  water  quality  constituents, it affects aquatic life with
each change.  These  effects  include  chemical  reaction  rates,
enzymatic functions, molecular movements, and molecular exchanges
between  membranes  within  and between the physiological systems
and the organs of an animal.

Chemical reaction  rates  vary  with  temperature  and  generally
increase  as  the  temperature  is  increased.  The solubility of
gases in water varies  with  temperature.   Dissolved  oxygen  is
decreased  by  the  decay  or  decomposition of dissolved organic
substances and the decay rate increases as the temperature of the
water increases reaching a maximum at  about  30°C  (86°F).   The
temperature  of  stream  water,  even during summer, is below the
optimum for pollution-associated bacteria.  Increasing the  water
temperature  increases the bacterial multiplication rate when the
environment is favorable and the food supply is abundant.

Reproduction cycles may be  changed  significantly  by  increased
temperature  because  this  function takes place under restricted
temperature ranges.   Spawning  may  not  occur  at  all  because
temperatures  are too high.  Thus, a fish population may exist in
a heated area only by continued  immigration.   Disregarding  the
decreased  reproductive  potential,  water  temperatures need not
reach lethal levels to decimate  a  species.   Temperatures  that
favor  competitors, predators, parasites, and disease can destroy
a species at levels far below those that are lethal.

Pish  food  organisms  are  altered  severely  when  temperatures
approach  or  exceed  90°F.   Predominant  algal  species change,
primary production is decreased, and bottom associated  organisms
may   be   depleted   or   altered  drastically  in  numbers  and
distribution.  Increased water  temperatures  may  cause  aquatic
plant nuisances when other environmental factors are favorable.

Synergistic actions of pollutants are more severe at higher water
temperatures.  Given amounts of domestic sewage, refinery wastes,
oils,   tars,  insecticides,  detergents,  and  fertilizers  more
rapidly deplete oxygen in water at higher temperatures,  and  the
respective toxicities are likewise increased.

When  water  temperatures increase, the predominant algal species
may change from diatoms to  green  algae,  and  finally  at  high
temperatures  to blue-green algae, because of species temperature
preferentials.  Blue-green algae can cause serious odor problems.
The number and distribution of  benthic  organisms  decreases  as
water  temperatures  increase  above  90°F, which is close to the
tolerance limit for the population.  This could seriously  affect
certain fish that depend on benthinc organisms as a food source.

The cost of fish being attracted to heated water in winter months
may be considerable, due to fish mortalities that may result when
the fish return to the cooler water.
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 Rising   temperatures   stimulate  the  decomposition   of   sludge,
 formation  of  sludge gas, multiplication of  saprophytic  bacteria
 and   fungi   (particularly  in the presence of  organic wastes),  and
 the   consumption  of  oxygen  by  putrefactive  processes,   thus
 affecting  the esthetic  value of a water course.

 In general, marine water temperatures do not  change as rapidly or
 range as  widely  as those of freshwaters.   Marine and estuaririe
 fishes, therefore, are  less tolerant  of  temperature  variation.
 Although  this  limited tolerance is greater  in estuarine than in
 open  water marine species, temperature changes are more important
 to those fishes in estuaries and  bays  than  to  those  in  open
 marine  areas, because  of  the nursery and replenishment functions
 of  the  estuary  that  can  be  adversely  affected   by  extreme
 temperature changes.

 Most  of  the  washing  operations in flat glass manufacturing  and
 fabrication require warm-to-hot water and at  least one  stage  of
 the   washwater  is generally heated.  Some data on water tempera-
 tures immediately following the washers  has  been  presented  in
 this  report.   Temperature  increases  at  this  point  are much
 greater than at the end of the pipe immediately  before  the   re-
 ceiving  stream.   Dilution  with  once-through cooling water  and
 natural cooling in the  sewer pipe tend to reduce  discharge  tem-
 peratures  to  less than 4.7°C (10° F)  over ambient.  Substantial
 temperature increases may  adversely  affect  aquatic  organisms;
 insufficent  data is available at the present time, however, upon
 which to base limitations.  These will be set at a later date.

 DISSOLVED SOLIDS
In  natural  waters  the  dissolved  solids  consist  mainly   of
carbonates,   chlorides,   sulfates,   phosphates,  and  possibly
nitrates of  calcium,  magnesium,  sodium,  and  potassium,  with
traces of iron, manganese and other substances.

Many  communities in the United States and in other countries use
water supplies containing 2000 to 4000 mg/1 of  dissolved  salts,
when   no  better  water  is  available.   Such  waters  are  not
palatable, may not quench thirst, and may have a laxative  action
on  new  users.   Waters  containing more than 4000 mg/1 of total
salts are generally considered unfit for human use,  although  in
hot  climates  such  higher  salt concentrations can be tolerated
whereas  they  could  not  be  in  temperate  climates.    Waters
containing 5000 mg/1 or more are reported to be bitter and act as
bladder  and  intestinal  irritants.  It is generally agreed that
the salt concentration of good, palatable water should not exceed
500 mg/1.

Limiting concentrations of dissolved solids for fresh-water  fish
may  range  from  5,000  to 10,000 mg/1, according to species and
prior acclimatization.  Some fish are adapted to living  in  more
saline  waters,  and a few species of fresh-water forms have been
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found in natural waters with a salt concentration  of  15,000  to
20,000  mg/1.   Fish  can  slowly  become  acclimatized to higher
salinities, but fish in waters of  low  salinity  cannot  survive
sudden  exposure to high salinities, such as those resulting from
discharges of oil-well brines.  Dissolved  solids  may  influence
the  toxicity  of  heavy metals and organic compounds to fish and
other aquatic life, primarily because of the antagonistic  effect
of hardness on metals.

Maters  with total dissolved solids over 500 mg/1 have decreasing
utility as irrigation water.  At 5,000 mg/1 water has  little  or
no value for irrigation.

Dissolved  solids  in  industrial  waters  can  cause  foaming in
boilers and cause interference with cleaness, color, or taste  of
many  finished  products.  High contents of dissolved solids also
tend to accelerate corrosion.

Specific conductance is a measure of the  capacity  of  water  to
convey  an  electric  current.   This  property is related to the
total concentration of ionized  substances  in  water  and  water
temperature.   This  property  is frequently used as a substitute
method of quickly estimating the dissolved solids concentration.

Dissolved solids are critical for all washing operations, and the
concentrations must be kept low enough so that  spotting  of  the
glass  does not occur.  Deionized water is used in some cases for
a final  rinse.   Because  low  dissolved  solids  is  a  process
consideration,   relatively  small  concentrations  of  dissolved
solids are discharged in the process waste water.  Glass is inert
and/ therefore, dissolved-solids sources are limited  to  calcium
sulfate  in  the  plate  process,  sodium  sulfate  in  the float
process, various parting materials used in  fabrication,  and  to
concentration   increases  due  to  evaporation.   Owing  to  the
relatively low concentration, limited dissolved-solids data  have
been  collected  by  the industry.  Much of the industry includes
the auxiliary wastes  in  the  process-waste  stream,  making  it
difficult  to  determine  the dissolved solids contributed by the
process.  The contribution by auxiliary  wastes,  which  are  not
covered  by this study, is generally more significant.  The major
concern for dissolved solids is in a recycle system where removal
is  necessary  because  of  the  low  washwater  dissolved-solids
requirements.
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                           SECTION VII

                CONTROL AND TREATMENT TECHNOLOGY
As   indicated  in  Chapter  V,  the  major constituents requiring
treatment for primary  flat  glass  manufacturing  and  automotive
fabrication  are suspended solids and oil.  The treatment methods
presently  employed  have  been  developed  for   this   purpose.
Effluent values are given as monthly averages except as noted.

No   process  waste water and, therefore, no treatment is required
for  the  rolled  and  sheet  subcategories.    In   all   cases,
polyelectrolyte  addition  with lagoon sedimentation is practiced
for  plate glass manufacturing.  Upgrading the lagoon  system  and
partial  recycle  are  methods  of  reducing waste loads from the
plate process.  Float waste water contains pollutants  in  fairly
low  concentrations and presently is not treated.  Solid tempered
automotive glass waste water is also  not  treated  but  oil  and
suspended  solids  must be reduced.  Flotation and centrifugation
are  used to reduce the oil discharged by  the  windshield  fabri-
cation  process.   Additional  treatment  will further reduce and
assure low discharge levels in the flat glass industry.  In  some
cases, treatment technologies developed for other industries will
have to be used.

SHEET AND ROLLED GLASS MANUFACTURING

No   process waste water is produced by the sheet and rolled glass
subcategories.  The manufacturing processes are dry with  process
water used only in the batch for dust control.

Both  subcategories have significant cooling requirements and use
substantial  quantities  of  cooling  water.   Although   cooling
systems  are  not specifically covered in this report, one system
related to water pollution control will be discussed briefly.

Several sheet glass plants are eliminating a pollution problem by
disposing of chromium  treated  cooling  tower  blowdown  in  the
batch.   Approximately  42 I/metric ton (10 gal/short ton)  can be
disposed of by this method.   This is  especially  interesting  in
view  of  the  adverse affect of chromium on glass quality.  At a
low concentration, which has not been  defined,  chromium  causes
"stones"   or  imperfections  in  the  glass.    Apparently,  this
concentration is not exceeded in sheet glass or, more likely, the
imperfections are not significant because the  glass  is  thinner
and of lower quality than other types of primary glass.

Discussions  with  glass  industry personnel have indicated great
reluctance  to  consider  disposal  of  cooling  tower  blowdown,
especially  chromium  treated,  in the batch for plate, float, or
rolled glass.  These glasses are thicker and  of  higher  quality
and it is thought that noticeable imperfections in the glass will
result.   An unsuccessful attempt at batch disposal could be quite
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costly.   Glass  melting  is  a  continuous  process with a large
volume  of  melted  glass  contained  in  the  furnace.   If   an
undesirable  concentration of some contaminant is introduced into
the glass furnace, it might result in a week or two of production
of unusable glass to dilute the furnace contents to an acceptable
level.

Disposal of other glass plant auxiliary wastes in the batch  such
as boiler blowdown and softener and deionizer regenerants is also
within  the  realm  of possibility, however, none of these has as
yet teen demonstrated.  Washwater, especially from the float pro-
cess, should also be amenable to batch disposal.  Although  batch
disposal is not a cure-all for primary glass waste water disposal
(the  volume  of  process and auxiliary waste water discharge far
exceeds the 42 I/metric ton (10 gal/short ton)  maximum  that  can
be  accepted  by  the batch),  experimentation within the industry
should be encouraged.  Batch disposal of cooling  tower  blowdcwn
for sheet glass manufacturing has been demonstrated and should be
applicable  at many plants.  It is too early, however, to predict
universal applicability and each process should be considered  on
an individual basis.

PLATE GLASS MANUFACTURING

Plate glass manufacturing produces a large volume of waste water,
high  in suspended solids with lesser concentrations of dissolved
solids, BOD, and COD.  Waste water  sources  and  characteristics
are described in Section V.  Plate glass manufacturing is rapidly
being  replaced  by the float process.  Float glass is of similar
quality, but is less  expensive  to  produce  and  process  waste
waters  are  insignificant  compared  to the plate process.  Only
three plate glass plants remain in this country and at least  two
of these may be closed by 1977.

Owing  to  the  high  operating  costs and pollution load, no new
plate glass facilities are anticipated.  The  industry  trend  of
replacing plate glass with float glass has shown that plate glass
manufacturing  can  be  successfully  eliminated, therefore, only
treatment  technologies  for  reducing  pollutant  loadings  from
existing plate glass plants will be discussed.

In-Plant Modifications

No  apparent  in-plant  modifications of pollutional significance
have been developed for the plate  glass  manufacturing  process.
The  three  remaining  plants  are  relatively  modern  by  plate
standards.  Plate glass technology  development  ended  with  the
advent of the float process.   Sand and rouge recovery systems are
based on the latest technology.

In  one  case, cerium oxide rather than iron oxide is used as the
polishing medium.  This plant also has the most  efficient  waste
water  treatment  of all of the plate glass plants indicating the
possible beneficial effects of cerium oxide.  Cerium oxide has  a
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 higher  specific  gravity than  rouge  which may account  for  better
 settlability.  The switch from  rouge  to cerium oxide was made  for
 reasons other than pollution  control  and  comparative effluent
 data  before  and  after  the   change  do  not  exist.   Although
 insufficient information is available  to  conclude  that   cerium
 oxide  is more easily removed from plate waste water, this  method
 might be considered where  problems   are  experienced   with iron
 oxide removal.

 Existing Treatment Systems (Alternative A)

 Each  of  the  three  remaining plate  glass  plants   use  lagoon
 treatment with polyelectrolyte  added  to the influent waste  water.
 The typical flow rate is 45,900 I/metric  ton   (11,000  gal/short
 ton)  or  18,168  cu  m/day   (4.8  mgd)  and the suspended  solids
 loading is 690 kg/metric ton  (1,375 Ib/short ton) or 15,000 mg/1.
 A cationic polyelectrolyte is added to the  influent  sewer with
 mixing  accomplished through the natural turbulance of  the  water.
 The typical lagoon is square, has an  area of  approximately 5.26
 ha  (13 acres) and a working depth of  2.44 m (8 feet).

 Available   data   indicate   the  highest  efficiency  presently
 available using this system is  99.6%  suspended  solids  reduction
 to  produce  an  effluent  concentration  of 2.5 kg/metric  ton  (5
 Ib/short ton) or 54 mg/1.  The  COD is reduced  approximately  90%
 to  0.45 kg/metric ton  (0.9 Ib/short ton) or 10 mg/1.   Additional
 treatment methods can be  employed  to  further  reduce effluent
 suspended solids levels.

 Additional Treatment Methods

 Several methods for upgrading existing plate glass lagoon systems
 to  increase  suspended  solids  removal efficiency are apparent,
 Improved polyelectrolyte addition and a two-stage  lagoon   system
 should  reduce suspended solids to 30 mg/1.  An additional  reduc-
 tion to less than 5 mg/1 can be accomplished by  sand   filtration
 of the lagoon effluent.  The filter volume can in turn  be reduced
 by recycling the lagoon effluent back to the grinding and polish-
 ing  process.   These  methods  of  treatment  are illustrated in
 Figure 11.

 Lagoon Improvements (Alternative B)-

 It should be possible to reduce lagoon effluent suspended   solids
to 30 mg/1 or 1.38 kg/metric ton (2.75 Ib/short ton)  by improving
 coagulant  mixing  and  using  a  two-stage  lagoon  system.  The
 maximum daily discharge from this system will be 60 mg/1 or  2.76
kg/metric  ton (5.5 Ib/short ton).   A mixing tank is added  at the
 lagoon influent to assure proper polyelectrolyte dispersion.  The
mixing is for one minute or less and is  of  sufficient  velocity
that  essentially  instantaneous mixing of the polyelectrolyte is
assured.

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                      WATER
GRINDING
POLISHING
 WASHING
                                       I
                                       1
                                  POLYEtECTROLYTE
                                    FLASH  MIXER
                                      PRIMARY
                                      LAGOON
                                  POLYELECTROLYTE
                                    FLASH MIXER
 BACKWASH TO
PRIMARY MIXER
                                     SECONDARY
                                      LAGOON
             SAND
             FILTER
            SURFACE
           DISCHARGE
                RETURN TO
                GRINDING
                                       PUMP
                                      STATION
                           FIGURE 11
                    WASTEWATER  TREATMENT
                        PLATE  PROCESS
                            72

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The  lagoon  is  divided  into  two  stages  by  constructing  an
additional  levee.   This  will produce two lagoons of 2.U3 ha  (6
acres) each in the typical  plant.   The  two-stage  system  will
reduce  the  effects of wind action which is a major cause of low
effluent quality.  A second mixing tank with provision for adding
additional  polyelectrolyte  between  the  lagoon   segments   is
provided.   It  is  not  certain  that the second polyelectrolyte
addition step will be necessary, but the  equipment  is  included
for cost estimating purposes.

The  minimum  allowable lagoon surface area and detention time is
not known.  The data from existing one-cell lagoon systems  indi-
cate  no  correlation  between surface area or detention time and
suspended solids removal.  This may be due to poor  design,  lack
of  solids  removal,  or  other  factors.   The  lowest  effluent
concentration was  produced  in  the  lagoon  with  the  shortest
detention  time.   This  lagoon  was  used  as  the basis for the
recommended improvements.  The other  lagoon  systems,  having  a
longer  detention  time,  if  properly  operated,  should have no
trouble achieving the same effluent levels.

Many polyelectrolytes are on the market, but  laboratory  testing
is  required  to  determine  the  most  efficient  one  for  each
application.  Based on current practice in glass plants, a liquid
cationic  polyelectrolyte  is  most  effective,   although   some
inorganic coagulants may also be effective.  The latter should be
avoided,  if possible, where recycle is considered because of the
dissolved solids increase.

Coagulation and sedimentation are widely employed for both  water
and  waste  water treatment.  An effluent concentration much less
than 30 mg/1  suspended  solids  is  achieved  in  many  systems.
Although  most  conventional  systems  are  operated in specially
designed tanks, there is no evidence to indicate  that  a  lagoon
system  with  sufficient  protection against short circuiting and
wind cannot achieve an average  effluent  of  30  mg/1  suspended
solids.

Filtration (Alternative C)-

Lagoon  effluent  suspended solids can be further reduced to less
than 0.23 kg/metric ton {0.46 Ib/short ton)  or 5  mg/1  by  rapid
sand  filtration.   The entire lagoon effluent is filtered through
a standard gravity sand filter at an assumed 163  1/min/sq  m  (4
gpm/sq  ft).    The filter backwash is recycled to the head of the
lagocn for suspended solids removal.

Rapid sand filtration is a  widely  used  and  thoroughly  proven
technology.   Such filters are used extensively in water treatment
plants following coagulation and sedimentation.   Suspended solids
levels  substantially  below  5  mg/1  are almost the rule in the
water treatment  industry  and  similar  values  have  also  been
achieved  for the filtration of secondary sewage effluent.   Other
filters such as mixed media, pressure,   and  upflow  filters  are
                             73

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also available and may be more desirable in some cases, but rapid
sand  filters  are  chosen for illustrative purposes because more
background  information  on  cost  and  treatment  efficiency  is
available.

Filtrationmand Recycle (Alternative D)-

The volume of water requiring filtration can be substantially re-
duced  by  recycling  the  lagoon  effluent  back to the grinding
process.  Recycle is not presently employed in the industry,  but
there   is  adequate  reason  to  believe  that  it  is  feasible
especially if lagoon effluent suspended solids are reduced to  30
mg/1.   In most cases, this is a lower concentration than the raw
river water presently being used.

A liberal 20% blowdown from the  recycle  system  is  assumed  to
allow for any unforeseen dissolved solids problems.  It is likely
that  a  iower  blowdown  rate can and will be achieved to reduce
filtration requirements.   The filtered effluent suspended  solids
concentration  will still be 5 mg/1 or less but, owing to the 80%
volume reduction, the effluent loading will be reduced  to  O.OU5
kg/metric  ton (0.09 lb/ short ton).  COD will be reduced to 0.09
kg/metric ton (0.18 Ib/short ton) .

FLOAT GLASS MANUFACTURING

Float glass manufacturing is rapidly replacing  the  plate  glass
process  as  the  method  for  producing high quality thick glass
sheets.  Conversion to the float process has drastically  reduced
pollution  loadings  related  to  the manufacture of this type of
glass.  Washing is required for some types of glass and  this  is
the   only   process  waste  water  resulting  from  float  glass
production.  Raw waste suspended solids loadings are reduced from
690 kg/metric ton (1,375 lb/short  ton)   for  plate  glass  to  2
g/metric  ton  (0.0041  Ib/short ton)  for float glass.  The waste
water loading for other parameters is equal to or less than  that
for  suspended  solids.  More detailed information on waste water
characteristics is presented in Section V.  The typical  flow  is
only  138  I/metric ton (33 gal/short ton)  or 136 cu m/day (0.036
mgd).  Owing to the high quality, float  washwater  is  presently
not treated,

In-Plant Modifications

Until  several  years  ago,  detergents  were  used  in the float
washer.  In an effort to reduce phosphorus discharge and  prevent
foaming  in  the  receiving  body  of water, most plants have now
found  that  sufficient  washing  can  be  accomplished   without
detergents.   Non-detergent  washing is now typical.  There is no
evidence to indicate that elimination of detergents in the  float
wash  is  detrimental to the product or the process.  Elimination
of detergents in the float'  wash  is  believed  possible  in  all
ca se s.
                             74

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Recycling   washer   systems   are   typical  for  the  industry.
Recycling,  although  having  no  effect  on  the   quantity   of
pollutants   discharged,   does  conserve  water  and  should  be
encouraged.  A typical system involves one or two stages of  city
water  washing  and  a  final,  totally  recycled deionized water
rinse.  Dissolved solids are removed in the first  ,washer  stages
and  any  residual  that  might  cause spotting is removed by the
deionized water rinse.  Deionizer regeneration  requirements  are
governed  by  the  buildup  of  dissolved solids in the preceding
wash.  The more dissolved solids  carried  over  into  the  final
rinse, the more picked up and thus removed by the deionizer.

Recycle and Treatment_Methgds

Waste   water   phosphorus   loadings   can   be   eliminated  by
discontinuing the  detergent  wash.   Oil  and  suspended  solids
loadings   can  be  reduced  by  diatomaceous  earth  filtration.
Further reduction of these  pollutants  may  be  accomplished  by
recycling   the   wash   water   to  other  processes.   Complete
elimination of the discharge of process waste water pollutants is
highly theoretical.  Evaporation to dryness of waste waters poses
both severe economical and environmental problems.  A  discussion
of   the   treatment  technologies  to  achieve  the se  pol1utant
reductions is included below and illustrated in Figure 12.

Detergent Elimination (Alternative A)-

The use of detergents for float glass washing can  be  eliminated
without  any adverse effects on the manufacturing process as dis-
cussed above.   Although this  is  an  in-plant  modification,  by
reducing  phosphorus,  it has the same effect as treatment and is
considered as such for the sake of  continuity  in  this  report.
Elimination  of  detergent essentially eliminates phosphorus from
float process waste water as no other source is known.   No  data
is  available on the quantity of phosphorus presently discharged,
but elimination  of  detergents  will  achieve  essentially  100%
removal.    With  credit  given for evaporation,  trace phosphorus,
and analytical error, a typical plant  can  achieve  an  effluent
phosphorus  concentration  of  0.05 g/metric ton (0.0001 lb/short
ton)  or 0.5 mg/1.

Filtration (Alternative B)  -

A further decrease in suspended solids and oil can be achieved by
filtering the  wash water through a diatomaceous earth filter with
a media especially treated for oil removal.   This type of  filter
is  commonly  used  to remove oil from boiler condensate.   In the
glass container industry,  a diatomaceous earth  filter  is  being
used  at  one  plant to remove machine oil, and emulsified cutting
oils similar to those used in the flat glass industry.

The diatomaceous earth filtration  system  will  consist  of  the
filter,  precoat tank,  and a slurry tank for continuously feeding
diatomaceous earth.   The filter will be of the dry discharge type
                             75

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so that the sludge will not require dewatering.  Sufficient units
will be provided to function with one unit down for  cleaning  or
maintenance.   Experimentation  on  flat glass wash water will be
required to develop exact design parameters, but the  approximate
filter  rate will be 20.4 to 40.7 1/min/sq m (0.5 to 1 gpm/sq ft)
and approximately 0.9 kg(2 Ib)  of diatomaceous earth is  required
per 0.45 kg (1 Ib) of oil removed.

Effluent oil and suspended solids should be reduced to well below
5   mg/1   by  diatomaceous  earth  filtration.   These  loadings
expressed in terms of typical plant production are as follows:
         Suspended Solids
         Oil
0.70 g/kkg  (0.0014 Ib/short ton)
0.70 g.kkg  (0.0014 Ib/short ton)
Recycle to Batch nand Cooling Tower (Alternative B)-

Float glass washwater, where no detergents  are  used  and  after
filtration,  is  of  high  quality.  There exists the possibility
that- this water can then be recycled as batch  water  or  cooling
tower  make-up  in  some  plants.   The  data  indicate  very low
increases of all contaminants result from washing.  The dissolved
solids will average 300 to 400  mg/1  and  the  concentration  of
other   constituents  will  be  less  than  5  mg/1.   The  exact
temperature is not known, but in one case was  measured  at  37°C
(98°F).  With the exception of temperature, these characteristics
are  not  significantly  different  from  those of the city water
presently being used in the batch or as cooling tower makeup.

Washwater can be collected and pumped through overhead piping  to
the  batch  house  or cooling tower.   The maximum flow acceptable
for the batch  is  42  I/metric  ton  (10  gal/short  ton).   The
remaining 96 I/metric ton (23 gal/short ton)  may be pumped to the
cooling  tower.   These  methods would reduce, but not eliminate,
the discharge of pollutants from the float process.  Waste  water
recycled  to  the cooling tower would eventually be discharged to
the environment via the blow-down.   The  real  benefit  of  this
disposal method is in water conservation.

Disposal  to  the  batch would result in a 33% reduction in waste
water pollutants.  This method  has  not  been  demonstrated  but
owing  to  the  high  quality  of  this waste water, there are no
apparent  reasons  why  this  disposal  method  should   not   be
investigated.   In  some cases batch disposal may be precluded if
liquid caustic is used.  When soda ash is in short supply,  liquid
caustic is substituted.  It then supplies all the water that  can
possibly be added to the batch.

Total Recycle  (Alternative D)-

It is theoretically possible to recycle the washwater back to the
washer  following  dissolved  solids  removal.   Three  dissolved
solids removal systems are sufficiently developed at  present  to
                             76

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     WATER
  RETURN  TO
FLOAT WASHER
                DIATOMACEOUS
                   EARTH
                   FILTER
                  REVERSE
                  OSMOSIS
                   BRINE
                EVAPORATION
                                           RECYCLE TO
                                         BATCH OR COOLING
                                             TOWER
                 SOLIDS  TO
                 PERMANENT
                  STORAGE
                 FIGURE  12
         WASTEWATER  TREATMENT
              FLOAT PROCESS
               77

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be  considered  currently  available.   These  are  ion exchange,
electrodialysis, and reverse osmosis.  Ion  exchange  is  already
used  extensively  for final rinse water treatment; however, this
process  significantly  increases  the  total  dissolved   solids
loadings   when  regeneration  wastes  are  considered.   Current
research and  development  effort  in  dissolved  solids  removal
technology  center  on  reverse osmosis.  Significant improvement
and future development of  this  process  are  anticipated.   For
these  reasons,  reverse osmosis is selected for dissolved solids
removal in this report.

It is assumed that reverse osmosis will concentrate the dissolved
solids approximately five times and produce a  waste  water  flow
rate  of  2056  of  the  initial volume treated.  This waste water
stream must be disposed of if any net pollution reduction  is  to
te achieved.  It may be possible to discharge this waste water to
the batch, but this has not been demonstrated.  The proven method
of evaporation to dryness will be assumed in this report.

A  complete  recycle system using reverse osmosis might be set up
as follows.  The washwater discharge will first  pass  through  a
diatomaceous  earth filter with an oil absorptive media to reduce
both oil and suspended solids to less than 5 mg/1.  Both of these
constituents have an adverse effect on the reverse  osmosis  mem-
branes.    The   filter  is  a  dry  discharge  type,  and  spent
diatcmaceous earth is discharged at approximately 1556 dry  solids
content,  suitable  for  land  disposal.   Following  filtration,
dissolved solids are removed by reverse osmosis.   The  water  is
forced  at  high  pressure  through a semipermeable membrane that
retains most of the dissolved ions.  Product water is returned to
the washer and the waste  brine  is  evaporated.   The  steam  is
condensed  and  also  returned to the washer and the salt residue
must be stored permanently in  lined  basins  to  prevent  ground
water contamination.

No  total  recycle systems have been demonstrated or contemplated
in the flat,glass industry.  At the present time, reverse osmosis
is  used  mainly  for  boiler  water  treatment,   generally   in
competition  with  ion  exchange.   With the present state of the
art, it is impossible to accurately predict  the  feasibility  of
the  system  without  pilot  plant  data.   Even  if  technically
feasible, the cost/ benefit ratio  will  be  high.   Capital  and
operating  costs are high, relatively large amounts of energy are
required, and two types of solid waste must  be  disposed  of  on
land.    The  untreated  washwater  contains  only  300-400  mg/1
dissolved solids and less than 15 mg/1 of other constituents.  In
most cases these concentrations will not significantly affect the
receiving stream.

SOLIC TEMPERED AUTOMOTIVE GLASS FABRICATION

Solid tempered automotive  glass  fabrication  produces  a  waste
water with, significant quantities of suspended solids, and lesser
                               78

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quantities  of  oil  and  BOD.   The  BOD  is  the  result of  oil
contamination.  Typical raw waste water characteristics are:
         Suspended Solids
         Oil
         BOD
100 mg/1
 13 mg/1
 15 mg/1
These and  other  waste  water  characteristics  are  more   fully
described in Section V.  The typical flow rate is 49 1/sq m  (1200
gal/1000  sq  ft).   None  of  the plants studied presently  treat
solid tempered automotive waste water.

In-Plant Modifications

In-plant modifications may reduce waste water volume and loading.
Most plants presently collect the sludge removed from the coolant
recycle system for disposal as landfill; however, in a few   cases
this  is  discharged to the sewer system imparting an unnecessary
load on the treatment system.  The method of collection  and de-
watering  used  by  most  plants is a chain-driven scraper system
which scrapes the sediment to discharge at one end  of  the  tank
and  skims  the floating material for discharge at the other end.
The combined sludge is collected  in  a  portable  container for
hauling  to  landfill.   The  sludge  has an approximate moisture
content of 90# and is well suited for land disposal.

In some plants, cooling water is sprayed directly onto the glass.
Although little contamination is picked up in this quenching pro-
cess, the water is in contact with the glass and is, therefore, a
process waste water.  Quenching may be replaced  by  air  cooling
thereby reducing the volume of waste water requiring treatment.

Waste   water   volumes,  but  not  the  quantity  of  pollutants
discharged, can be reduced by using recycling washers.  Generally
older washers tend to be of  the  once-through  type,  while new
equipment  is  generally  recycling  with a two-stage system most
common.  Water  is  pumped  over  the  glass  from  two  separate
reservoirs,  and  make-up water is added to the second wash  tank.
Overflow from second  tank  goes  to  the  first  wash  tank and
overflow from this tank is discharged to the sewer.

Sufficient  water  pressure and volume is required for the washer
sprays to dislodge and flush away glass particles, oil,  or  dirt
that might be on the glass.  Recycling does not significantly af-
fect  these  requirements until the concentration of contaminants
increases to the point where residue is left on the glass^   Some
recycling  can  be  employed  in all plants, even where dissolved
solids are high.  Only one recycle will cut the waste water  flow
to half that required for a once-through system.

The  extent  of  recycle  is  limited by oil and suspended solids
buildup.   It  is  theoretically   possible   to   remove    these
contaminants   using   a   diatomaceous  earth  filter  with  oil
absorption media.  This type equipment is discussed below in more
                            79

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Coagulation-sedimentation for suspended solids removal is a well-
established  process  that  can  be successfully applied to solid
tempered automotive glass waste water.  An effluent  of  25  mg/1
suspended  solids  or  1.22 g/sq m (0.25 lb/1000 sq ft) should be
readily achieved and the maximum daily concentration  should  not
exceed  40 mg/1 or 1.95 g/sq m (0,4 lb/1000 sq ft) .  It is likely
that oil and, therefore, BOD will also be removed,  especially  if
inorganic   coagulants   are  used,  but  lacking  substantiating
evidence, no credit is given for oil and BOD removal.   Dissolved
solids  will  be  increased  somewhat if inorganic coagulants are
used.

Filtration (Alternative C) -

A further decrease in suspended solids and oil can be achieved by
filtering the  settled  effluent  through  a  diatomaceous  earth
filter  with  a  media  especially treated for oil removal.  This
type of filter  is  commonly  used  to  remove  oil  from  boiler
condensate.

The diatomaceous earth filtration system will consist of the fil-
ter,  precoat  tank,  and  a slurry tank for continuously feeding
diatomaceous earth.  The filter will be of the dry discharge type
so that the sludge will not require dewatering.  Sufficient units
will be provided so that the system  will  continue  to  function
with  one unit down for cleaning or maintenance.  Experimentation
on solid tempered automotive waste  water  will  be  required  to
develop  exact design parameters, but the approximate filter rate
will te 20.4 to  40.7  1/min/sq  m  (0.5  to  1  gpm/sq  ft)  and
approximately 0.9 kg (2 Ib) of diatomaceous earth is required per
0.45  kg   (1  Ib)  of  oil  removed.   oil, rather than suspended
solids, is expected to be limiting; therefore, approximately 1.28
g/sq m  (0.26  lb/1000  sq  ft)  of  diatomaceous  earth  will  be
required.

Effluent oil and suspended solids should be reduced to well below
5  mg/1  by  diatomaceous  earth  filtration.   The BOD reduction
resulting from oil removal can only be  estimated.    An  effluent
BOD of 10 mg/1 is assumed although actual values will probably be
lower.   These  loadings  expressed  in  terms  of  typical plant
production are as follows:
         Suspended Solids
         Oil
         BOD
0.24 g/sq m
0.24 g/sq m
0.49 g/sq m
(0.05  lb/1000  sq ft)
(0.05  lb/1000  sq ft)
(0.10  lb/1000  sq ft)
COD will probably be reduced in equal or greater proportion
BOD.
                                  than
Equivalent  effluent  levels  can  also  be  achieved  using sand
filtration, as described for plate glass (waste water treatment),
if sufficient oil is  removed  in  the  coagulation-sedimentation
process.   Inorganic  coagulants  such  as  alum will absorb oil.
Trace quantities of oil  are  commonly  removed  by  coagulation-
                                82

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 quantities   of   oil   and   BOD.   The   BOD   is  the   result  of  oil
 contamination.   Typical raw  waste water  characteristics  are:
          Suspended Solids
          Oil
          BOD
100 mg/1
 13 mg/1
 15 mg/1
 These and   other  waste  water  characteristics  are  more   fully
 described  in  Section V.  The typical flow rate is U9 1/sq m  (1200
 gal/1000   sq  ft).   None  of  the plants studied presently  treat
 solid tempered automotive waste water.

 In-Plant Modifications

 In-plant modifications may reduce waste water volume and loading.
 Most plants presently collect the sludge removed from the coolant
 recycle system for disposal as landfill; however, in a few   cases
 this  is   discharged to the sewer system imparting an unnecessary
 load on the treatment system.  The method of collection  and de-
 watering   used  by  most  plants is a chain-driven scraper system
 which scrapes the sediment to discharge at one end  of  the  tank
 and  skims  the floating material for discharge at the other end.
 The combined  sludge is collected  in  a  portable  container for
 hauling  to  landfill.   The  sludge  has an approximate moisture
 content of  9036 and is well suited for land disposal.

 In some plants, cooling water is sprayed directly onto the glass.
 Although little contamination is picked up in this quenching pro-
 cess, the  water is in contact with the glass and is, therefore, a
 process waste water.  Quenching may be replaced  by  air  cooling
 thereby reducing the volume of waste water requiring treatment.

 Waste   water   volumes,  but  not  the  quantity  of  pollutants
 discharged, can be reduced by using recycling washers.  Generally
 older washers tend to be of  the  once-through  type,  while new
 equipment   is  generally  recycling  with a two-stage system most
 common.  Water  is  pumped  over  the  glass  from  two  separate
 reservoirs,  and  make-up water is added to the second wash  tank.
 Overflow from second^ tank  goes  to  the  first  wash  tank and
 overflow from this tank is discharged to the sewer.

 Sufficient  water  pressure and volume is required for the washer
 sprays to dislodge and flush away glass particles, oil,  or  dirt
 that might  be on the glass.  Recycling does not significantly af-
 fect  these  requirements until the concentration of contaminants
 increases to the point where residue is left on the glass.    Some
 recycling  can  be  employed  in all plants, even where dissolved
 solids are  high.  Only one recycle will cut the waste water  flow
 to half that required for a once-through system.

 The  extent  of  recycle  is  limited by oil and suspended solids
 buildup.   It  is  theoretically   possible   to   remove   these
contaminants   using   a   diatomaceous  earth  filter  with  oil
 absorption media.   This type equipment is discussed below in more
                            79

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detail,  complete recycle is limited by dissolved solids buildup,
with at least one company believing  that  300-400  mg/1  is  the
allowable maximum concentration.

Treatment Methods

The   major  contaminants  to  be  removed  from  solid  tempered
automotive glass are suspended solids and oil.  Treatment may  be
accomplished  at the individual washer or at end of pipe.  It may
be beneficial to consider individual treatment for  new  sources,
but  owing  to limited floor space, end of pipe treatment is most
practical for existing plants.  Location of the treatment  system
does not influence the degree of pollutant reduction.

Coagulation-sedimentation  and  filtration are common methods for
reducing suspended solids and oil that are  applicable  to  solid
tempered  waste  water.   These  treatment  methods and a recycle
system  using  reverse  osmosis  will  be   discussed   and   are
illustrated in Figure 13.  For cost estimating pruposes, no waste
water treatment is considered to be treatment Alternative A.

            Sedimentation (Alternative B) -

coagulation  and  sedimentation  is  commonly  used  in the water
industry for suspended solids removal.  Solid tempered automotive
glass waste water is not unlike some of the river water  commonly
treated  except  for  the  higher  oil  content.   It  should  be
possible, using  a  properly  designed  system  and  the  correct
coagulant  to  achieve an effluent suspended solids concentration
of 25 mg/1.

A solids contact  coagulation-sedimentation  system  with  sludge
dewatering  by centrifugation is assumed.  Solids contact differs
from conventional coagulation-sedimentation in that a portion  of
the  sludge is returned to provide more surface area for trapping
the newly coagulated particles.  Numerous organic  and  inorganic
flocculants  and  flocculant  aids  are  available and individual
testing will be required in each case to  determine  the  optimum
chemicals  and addition rate.  Polyelectrolytes are preferable to
inorganic flocculants because they do  not  contribute  dissolved
solids.   Owing  to the nature of the waste water, however, it is
likely that an inorganic flocculant such as alum or  a  coagulant
aid  such  as bentonite clay will be required.  Design parameters
cannot be accurately predicted without at least laboratory  scale
studies.  Conventional design rates can be assumed.

Sludge  will  be dewatered by centrifugation.  It is difficult to
accurately predict the sludge volume or moisture content  without
experimental   data.   A  conservative  estimate  of  the  volume
expressed in terms of production  is  21  cu  cm/sq  m  (0.07  cu
ft/1000 sq ft)  with an SOX moisture content.  Sufficient capacity
for  all  equipment  will be required so that effluent quality is
maintained  when  portions  of  the  equipment   are   down   for
maintenance.
                              80

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MAKE-UP
 WATER
  EDGE
GRINDING
            RECIflCULATION
            SETTLING TANKS
               SOLIDS TO
             LAND DISPOSAL
DRILLING
WASHING
QUENCHING


              CENTRIFUGE
                           CHEMICAL
                         COAQULATION
                                             4-
                                             i
                                                          WATER
                                        DIATOMACEOUS
                                           EARTH
                                         FILTRATION
                     RETURN TO
                      PROCESS
                                          REVERSE
                                          OSMOSIS
                                           BRINE
                                         EVAPORATION

                                          SOLIDS TO
                                      PERMANENT  STORAGE
           SOLID
                 FIGURE  13
         WASTEWATER  TREATMENT
    TEMPERED  AUTOMOTIVE GLASS FABRICATION
                                 81

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Coagulation-sedimentation for suspended solids removal is a well-
estafclished  process  that  can  be successfully applied to solid
tempered automotive glass waste water.  An effluent  of  25  mg/1
suspended  solids  or  1.22 g/sq m (0.25 lb/1000 sq ft)  should be
readily achieved and the maximum daily concentration  should  not
exceed  40 mg/1 or 1.95 g/sq m (0.4 lb/1000 sq ft) .  It is likely
that oil and, therefore, BOD will also be removed,  especially  if
inorganic   coagulants   are  used,  but  lacking  substantiating
evidence, no credit is given for oil and BOD removal.   Dissolved
solids  will  be  increased  somewhat if inorganic coagulants are
used.

Filtration (Alternative C) -

A further decrease in suspended solids and oil can be achieved by
filtering the  settled  effluent  through  a  diatomaceous  earth
filter  with  a  media  especially treated for oil removal.  This
type of filter  is  commonly  used  to  remove  oil  from  boiler
condensate.

The diatomaceous earth filtration system will consist of the fil-
ter,  precoat  tank,  and  a slurry tank for continuously feeding
diatomaceous earth.  The filter will be of the dry discharge type
so that the sludge will not require dewatering.  Sufficient units
will be provided so that the system  will  continue  to  function
with  one unit down for cleaning or maintenance.  Experimentation
on solid tempered automotive waste  water  will  be  required  to
develop  exact design parameters, but the approximate filter rate
will te 20.U to  40.7  1/min/sq  m  (0,5  to  1  gpm/sq  ft)  and
approximately 0.9 kg (2 Ib) of diatomaceous earth is required per
0.45  kg   (1  Ib)  of  oil  removed.   Oil, rather than suspended
solids, is expected to be limiting; therefore, approximately 1.28
g/sq m  (0.26  lb/1000  sq  ft)  of  diatomaceous  earth  will  be
required.

Effluent oil and suspended solids should be reduced to well below
5  mg/1  by  diatomaceous  earth  filtration.   The BOD reduction
resulting from oil removal can only be  estimated.    An  effluent
BOD of 10 mg/1 is assumed although actual values will probably be
lower.   These  loadings  expressed  in  terms  of  typical plant
production are as follows:
         Suspended Solids
         Oil
         BOD
0.24 g/sq m
0.24 g/sq m
0.49 g/sq m
(0.05  lb/1000  sq ft)
(0.05  lb/1000  sq ft)
(0.10  lb/1000  sq ft)
COD will probably be reduced in equal or greater proportion
BOD.
                                  than
Equivalent  effluent  levels  can  also  be  achieved  using sand
filtration, as described for plate glass (waste water treatment),
if sufficient oil is  removed  in  the  coagulation-sedimentation
process.   Inorganic  coagulants  such  as  alum will absorb oil.
Trace quantities of oil  are  commonly  removed  by  coagulation-
                                82

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sedimentation  in  water  treatment  plants.  The quantity of oil
removed and the  conditions  for  removal  cannot  be  accurately
stated  without  experimental data.  Another consideration is oil
fouling of the sand media.   Oil  will  tend  to  coat  the  sand
particles, and if sufficient quantities reach the filter, special
cleaning  procedures may be required.  Due to the unknown factors
related to  sand  filtration,  a  diatomaceous  earth  filtration
system is used for cost estimating.

Total Recycle (Alternative D)-

As  in all cases for the flat glass industry, it is theoretically
possitle to completely recycle  the  treated  effluent  following
dissolved  solids  removal.  No such system is presently employed
in the industry and only very general assumptions on the type  of
equipment required and the treatment efficiency can be made.

Filtered  effluent  can  be passed through a reverse osmosis unit
with 8036 of the flow returned to the plant.  The other 20%,  con-
sisting  of  waste  brine, is evaporated with the steam condensed
and returned to the plant and the salt permanently  stored  in  a
lined lagoon. , The reverse osmosis system is similar for all flat
glass applications and is discussed more fully in the float glass
treatment, section.

Dissolved   solids  data  from  the  automotive  glass  tempering
subcategory is limited and difficult to  interpret  because  high
dissolved  solids from auxiliary waste streams are included.  The
maximum allowable dissolved solids concentration is also unknown.
It is certain, however, that maximum  possible  recycle  will  be
practiced   prior   to  reverse  osmosis.   For  cost  estimating
purposes,a conservative estimate of half of the typical  flow  or
2U.4 1/sq m (600 gal/1000 sq ft)  will be assumed to be treated by
reverse osmosis.

Only  limited  benefit,  in terms of pollution reduction, will be
achieved by going to a complete recycle system.  Parameters other
than dissolved solids have essentially been eliminated  by  prior
treatment.   Available  data indicate a 100 mg/1 or 4.9 g/sq m (1
lb/1000 sq ft) dissolved solids increase at present water  usage,
which may be considered insignificant.  Relatively large capital,
operating,  and  power costs are required for reverse osmosis and
and an expensive landfill is needed for salt storage.

WINDSHIELD FABRICATION

Oil is the major contaminant to be removed from windshield  lami-
nation  waste  water.   The  oil  contributes  to  a high organic
loading as measured  by  COD.   Lesser  quantities  of  suspended
solids  and phosphorus are contributed as a result of seaming and
detergent washing.  Typical concentrations  of  these  parameters
are as follows:
         Oil
1700 mg/1
                              83

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         COD               1700 mg/1

         Suspended Solids    25 mg/1
         Phosphorus
5.6 mg/1
The  typical flow rate is 175 1/sq m (4300 gal/1000 sq ft).   More
detailed information on raw waste water  characteristics  may  be
found in section V.

A  combination of in-plant modification and end-of-pipe treatment
will most efficiently reduce pollutant concentrations.   Oil  and
phosphorus concentrations can be significantly reduced by modify-
ing washing techniques.  Residual oil and suspended solids can be
reduced  by  filtration.  An alternate to much of the oil removal
equipment  is  the  use  of  air  autoclaves.   In  theory,   zero
discharge  can  be  accomplished  by  using  reverse  osmosis for
dissolved solids removal.

In-Plant Modification

In-plant  modifications  can  significantly   contribute   to   a
reduction  of  waste  water volume and to the quantity of oil and
phosphorus discharged.

Reduction of waste water  volume  through  recycling  and  reuse,
though  not  reducing the quantity of pollutants discharged, will
reduce  the  size  of  required  treatment   units.    windshield
fabrication  waste water is almost entirely the result of washing
operations.  Three or four washes are required, depending on  the
production   process,   but   the   number  of  washes  does  not
significantly  affect  waste  water  volume.   Of  much   greater
significance  is  the  extent  of  washwater  recycle.   The same
general considerations govern  windshield  washwater  recycle  as
govern  solid  tempered washwater recycle.  Older washers tend to
be of the  once-through  type  and  some  type  of  recycling  is
generally  provided  on new equipment.   The typical plant employs
some recycling, but water usage has not been minimized.   Recycle
is  limited  by  factors,  such  as the manufacturing process and
background dissolved solicls concentration, that vary  from  plant
to  plant and cannot be generalized.  It is probable that maximum
recycle will be practiced wherever possible to minimize treatment
costs.

As described in Section V, it is now typical in the  industry  to
use an initial hot water rinse in the post lamination wash to re-
duce detergent usage and to eliminate the large volume of emulsi-
fied cil that is produced when an initial detergent wash is used.
This  practice  should  become standard and is assumed as part of
all treatment methods.

The limited available data on effluent phosphorus  concentrations
show  increases from near zero to 0.98 g/sq m (0.2 lb/1000 sq ft)
                            84

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indicating   significant   variation    in    detergent    usage.
Insufficient  information was available to define the reasons for
variable detergent usage, but it is apparent that some plants are
producing  acceptable  windshields  with  much  lower  phosphorus
discharges  than  others.   Two  exemplary plants are discharging
less than 0.2 g/sq m  (0.04 lb/1000 sq ft) and, therefore, it  can
be assumed that other plants can develop the technology to reduce
phosphorus to this level.

Another  method for reducing oil contamination to trace levels is
to use air rather than oil autoclaves.  Air  autoclaves  are  now
used  for  windshield  lamination by several small manufacturers,
but are not typical of the industry.  Greater  handling  problems
and apparently more manpower are required for air autoclaves.  It
was  impossible to obtain the background data necessary to deter-
mine the relative cost of the two systems.  However, one  company
has  indicated  that  its  analysis has shown a trade off for new
plants between the cost of extra handling  using  air  autoclaves
and  treatment requirements using oil autoclaves,  it is possible
to reduce  oil  to  trace  levels  by  using  diatomaceous  earth
filtration as indicated below.

Replacement  of  existing  oil  autoclaves  would be expensive in
terms of the investment  required  and  the  loss  of  production
during the change over.  It is likely, however, that owing to the
reduction in water usage and elimination of a potential pollution
problem, air autoclaves will be installed in new plants.

Treatment Methods

Primary methods of windshield fabrication washwater treatment in-
volve removal of the oil from post-lamination washwater.  Most of
the  oil  can te removed by centrifugation, plain flotation in an
American Petroleum Institute (API)  separator,  or  dissolved  air
flotation.    Suspended  solids and residual oil can be removed by
oil absorptive media filtration.  In theory, it is possible to go
to  complete  recycle  by   removing   dissolved   solids.     The
progression  of  treatment  methods  is illustrated in Figure 14.
Phosphorus concentrations will be lowered by  reducing  detergent
usage  as indicated above.  An initial hot water rinse is assumed
for all treatment methods.   For  cost  estimating  purposes,  no
waste  water  treatment is considered to be treatment Alternative
A.

lamination Washwater Treatment - (Alternative B)-

When an initial hot water rinse is used, the oil removed collects
in the initial wash reservoir.  The oil is not  emulsified  since
no  detergents  are  used  and  can readily be removed by gravity
separation.   A cream separator type centrifuge is  used  for  oil
removal  at  one  exemplary  plant  and  this  method is the most
efficient and economical of those observed.
                             85

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MAKE-UP
 WATER
OIL TO
 REUSE
HOT WATER
 PRERINSE
                  CENTRIFUGE
 'INTERMITTENT i
±    USE     |
                   DETERGENT
                     WASH
                    INITIAL  AND
                    FINAL RINSE
                                          WATER
                                           API
                                        SEPARATOR
                                         SLUDGE TO
                                         LAND DISPOSAL
                                      DIATOMACEOUS
                                          EARTH
                                          FILTER
                         RETURN TO
                          PROCESS
                                         REVERSE
                                         OSMOSIS
                                          BRINE
                                       EVAPORATION
                                        SOLIDS TO
                                    PERMANENT STORAGE
                                  FIGURE 14
                           WASTEWATER TREATMENT
                           WINDSHIELD  FABRICATION
                                   86

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Oil  and water are drawn from the surface of the hot  water   rinse
reservoir  and  passed  through a centrifuge commonly used in the
dairy industry for cream separation.  Concentrations of up to 50%
oil  are reduced to less than 50 mg/1.  The  oil  is  sufficiently
free of  water to be returned to the autoclaves and the water is
returned to the hot water rinse reservoir.  A cartridge, filter is
used prior to the centrifuge to minimize cleanouts due to  solids
build-up,  but  this  feature is optional as the suspended solids
content is low.

Sufficient oil is removed so that the only blowdown from the ini-
tial hot water rinse is the residual carried over on  the  glass.
So little oil reaches the second stage detergent wash that carry-
over on  the  glass  is  also the only blowdown or loss from the
detergent wash.  As a result, the  only  waste  water  from  this
exemplary post-lamination washer is blowdown from the third-stage
recycle rinse tank and once-through final rinse water.  The rinse
water  passes  through an API separator, but little removal takes
place in this unit.  An API separator is a good  safety  feature,
however, for trapping any oil that might accidently be discharged
and  will be included in cost estimates for this system.  Oil and
COD  levels, for the typical total plant effluent, can be  reduced
to   1.76 g/sq m (0.36 lb/1000 sg ft) and 4.9 g/sq m (1 lb/1000 sq
ft), respectively, or a reduction of over 98% in both cases.   No
credit  is taken for phosphorus and suspended solids removal with
this  system.   Similar  effluent  quality  can  be  obtained  by
treating  with  dissolved  air  flotation although at higher cost
because more sophisticated equipment and chemicals are  required.
With  this  system,  presently  in operation at another exemplary
plant, oil is not removed at the initial hot  water  rinse  tank,
but  hlowdown  from  this  and  all  the  wash and rinse tanks is
collected and treated by dissolved air flotation.   Free  oil  is
removed by belt skimmers prior to the flotation unit.

The  raw waste water is treated with polyelectrolyte to break any
emulsion and combined with a portion of the treated effluent that
has been pressurized and saturated with  air.   This  mixture  is
discharged  into  the  flotation  cell.   When  the  pressure  is
released, small bubbles are formed which cause the oil to  float.
A disadvantage of this system is that both skimmings and sediment
are  produced.  These are not suitable for reuse and are .disposed
of   as  landfill.     No   information   is   available   on   the
characteristics of this sludge.

A continuously recycling initial hot water rinse with oil removal
has  teen successfully demonstrated.  This system or the alternate
dissolved  air flotation system can be implemented throughout the
industry.   The  equipment  is  readily  available  and  can   be
installed  on  existing  equipment  without  any  interruption of
normal operations.  Cost estimates in Section VIII are  based  on
the centrifuge system.

Filtration (Alternative C) -
                              87

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Residual oil and suspended solids can be reduced to trace quanti-
ties  by  filtration in either of two systems that are available.
The entire windshield  fabrication  waste  water  stream  may  be
filtered  through  oil  absorptive diatomaceous earth or only the
laminating washwater  may  be  filtered  through  oil  absorptive
diatomaceous  earth  and  the  total  waste water stream filtered
through sand or an  equivalent  media.   The  diatomaceous  earth
filters are the same type discussed for solid tempered automotive
glass  treatment  and  flat glass.  Sand filters are discussed in
the section on plate glass treatment.

More process steps are required for sand filters because the fil-
ter backwash must be dewatered.  it is assumed that the  backwash
would  be treated by batch coagulation-sedimentation and that the
resulting sludge would be dewatered by centrifuge.  Approximately
a 20% solids  sludge  would  be  obtained  by  this  method.   No
additional  equipment  is  required  with  the diatomaceous earth
filters as these discharge a dry cake that is suitable  for  land
disposal.   The  diatomaceous earth filtration system is somewhat
less expensive and is used for cost estimating purposes.

Waste water effluent quality is assumed to be the same  for  both
systems.   Oil  is  reduced  at  least  SOX compared to the above
discharge and 99+X compared to the raw waste water for a residual
loading of 0.88 g/sq m (0.18 gal/1000 sq ft)  or 5 mg/1  based  on
the  typical flow rate,  suspended solids is reduced at least 80%
compared  to  the  raw  wa ste  water  for  a   typi cal   e f fluent
concentration  of  5  mg/1  and, therefore, has the same residual
loading as for oil.  The  effluent  loadings  are  conservatively
estimated  because  neither  system  has been demonstrated in the
flat glass industry.  No credit is taken  for  COD  reduction  as
most  of  the residual at this point is assumed to be contributed
by the vinyl washwater and not by oil.  This technology has  been
well  demonstrated in other industries and also in a few cases in
the glass industry.  In one  plant  making  glass  containers,  a
diatomaceous  earth  filter  is being used to remove machine oil,
and emulsified cutting oils similar to those  used  in  the  flat
glass   industry.    Another   plant  producing  windshields  has
installed a diatomaceous earth filter on its lamination washwater
system on a pilot basis.

Total Recycle (Alternative D)-

As with the other subcategories, it is theoretically possible  to
totally  recycle  windshield  fabrication  waste  water following
reverse osmosis.  No system of this type has been demonstrated or
anticipated by the  industry  for  windshield  fabrication  waste
water.   Many factors are related to the feasibility of a reverse
osmosis system and it can only be assumed that such .a  system  is
technically feasible for windshield lamination effluent.

The  anticipated  system  is similar to those indicated for float
glass and solid tempered automotive glass  fabrication.   Maximum
recycle  would  be achieved prior to reverse osmosis, but this is
                              88

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assumed to account for only a 33% reduction  because  significant
recycle  is  already  practiced  in  the  windshield  fabrication
process.  The reverse osmosis product water will be  recycled  to
the  manufacturing  process.  Waste brine will be evaporated with
the  steam  returned  to  the  process  and  the  residual   salt
permanently stored in a lined lagoon.

Capital and operating costs for a dissolved solids removal system
will  be  high  and  land  will  be  permanently  wasted for salt
storage.  Little benefit in terms of pollution reduction will  be
achieved  because waste water dissolved solids concentrations are
low.
                             89

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                          SECTION VIII

           COST, ENERGY, AND NON-WATER QUALITY ASPECTS

COST AND REDUCTION BENEFITS OF ALTERNATIVE TREATMENT AND  CONTROL
TECHNOLOGIES

Investment  and  operating  costs for the alternative waste water
treatment and control technologies described in Section  VII  are
presented here.

The  cost data include the traditional expenditures for equipment
purchase,  installation,  and  pperation  and  where   necessary,
include  solid  waste disposal.  No significant production losses
due to the installation of water pollution control equipment  are
anticipated.   The  costs  are  based  on  a  typical  plant  for
subcategories where no treatment is practiced and on an exemplary
plant where treatment is  employed.   In  some  cases  production
rates   and   waste   water   volume  are  adjusted  to  be  more
representative of the industry subcategory.

Investment  costs  include  all   the   equipment,   excavations,
foundations,  buildings etc., necessary for the pollution control
system.  Land costs are not included because the small additional
area required is readily available at existing  plants.   In  all
cases,  the  lagoon  systems  used  for  plate  glass waste water
treatment are already in operation and no additional
are required. •
land  costs
Costs  have  been  expressed as August 1971 dollars and have been
adjusted using the national average Water Quality Office - Sewage
Treatment Plant Cost Index.  The cost of capital was  assumed  to
be  8% and is based on information collected from several sources
including the Federal Reserve Bank.  Depreciation is  assumed  to
be 20 year straight line or 5% of the investment cost^  Operating
costs  include  labor,  material, maintenance, etc. , exclusive of
power costs.  Energy  and  power  costs  are  listed  separately.
August  1971  energy costs were assumed to be $.018 per kilowatt-
hour for electricity and $l/million BTU for  the  steam  required
for brine evaporation.

Six  subcategories have been defined in the development document.
Costs for each  subcategory  will  be  covered  separately.   The
various  alternative  treatment  systems  will  be  discussed and
factors that might affect the cost will be indicated.  No process
waste water results from sheet  and  rolled  glass  manufacturing
and,   therefore,   no   treatment   costs   result   for   these
subcategories.  Cost for the other subcategories  are  summarized
below.
        a^S Manufacturing

The typical plate galss manufacturing plant may be located in any
part of the country and is at least 12 years old.   Advanced plate
                             91

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glass  manufacturing  technology  is  used  but this has not been
improved since the early 1960's when the advantages cf the  float
process  became  apparent.   Annual  production  at  the plant is
approximately 150,000 metric tons.  Costs  and  effluent  quality
for the four treatment alternatives are summarized in Table 10.

Alternative A - Lagoon with polyelectrolyte Addition

Alternative  A  is  the  treatment universally practiced at plate
glass plants and includes polyelectrolyte  addition  to  the  raw
waste water followed by sedimentation in a one cell lagoon.

         Costs.  No additional cost.

         Reduction  Benefits.  Suspended solids.are reduced 99.6%
         and COD is reduced 90%.

Alternative B - Lagoon Improvements

Alternative B consists of partition  of  the  existing  one  cell
lagoons into two cells in series with polyelectrolyte addition at
the entrance to each.

         Costs.   Incremental  investment  costs  are $57,000 and
         total annual costs are $32,800 over Alternative A.

         Reduction  Benefits.   The  incremental   reduction   of
         suspended  solids  compared  to  Alternative  A  is 70%.
         Total reduction of suspended solids is 99.895.

            £ ~ Filtration

Alternative C is sand filtration of the lagoon effluent resulting
from Alternative B.
         Costs.  Incremental investment costs  are  $472,000
         total annual costs are $142,500 over Alternative B.
and
         Reduction Benefits.  The incremental reduction of suspended
         solid compared to Alternative B is 8336.  Total reduction
         of suspended solids is almost 100%.

            l2 ~" Filtration and Recycle

Alternative  D  is  recycle of the lagoon effluent resulting from
Alternative B to the plate glass grinders and sand filtration  of
a  2056  blow-down  prior  to  dishcarge  to the receiving stream.
Owing to the lower operating cost for Alternative D,  the  annual
cost for this system is less than for Alternative C.


         Costs.  Incremental investment costs are $127,000 over
         Alternative C but total annual costs re $36,800 less
         than Alternative C.
                              92

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                                     TABLE  10

                          WATER EFFLUENT TREATMENT COSTS
                             FLAT GLASS MANUFACTURING
                                    PLATE GLASS
Alternative Treatment or Control TechnolO'
  gies:


Investment

Annual Costs:

  Capital Costs

  Depreciation

  Operating and Maintenance Costs
    (excluding energy and power costs)

  Energy and Power Costs

           Total Annual Cost
Effluent Quality:


  Effluent Constituents

  Flow            ( I/metric  ton)

  Suspended Solids ( !kg/metric ton)

  COD             ( kg/metric ton)



  Flow            ( I/sec )

  Suspended Solids (.mg/1 )

  COD             ( mg/1.)



its)


Raw
Waste
Load
45,900
690.
4.6
210
15,000
100
A
0
0
0
0
0
0
($1,
B
57.
4.6
2.9
22.7
2.6
32.8
000)
C
529.
42.3
26.5
99.7
6.8
175.3
D
656.
52.5
32.8
49.7
3.5
138.5
Resulting Effluent
Levels
45,900
2.5
.45
210
54
10
45,900
1.38
.45
210
30
10
45,900
.23
.45
210
5
10
9,200
.045
.09
40
5
10
                                      93

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         Reduction Benefits.   Incremental reductions are 80% for
         suspended solids and COD compared to Alternative C.
         Total reductions are essentially 10096 for suspended
         solids and 98% for COD.

Three  plate  glass  plants  remain  in  operation  in the United
States.  All of these plants practice Alternative A treatment but
none of the other alternatives are practiced at  present.   There
is  nc  apparent benefit for phasing costs within an alternative.
However, where one alternative includes a  previous  alternative,
the earlier alternatives may be built first.

The  cost  of Alternative B is not expected to vary significantly
between plants.  The cost  of  Alternative  C  and  D  will  vary
somewhat  depending on the volume of water filtered.  A reduction
in plant water usage, although  theoretically  possible,  is  not
practical   because  extensive  in-plant  modifications  will  be
required.  For this reason, costs are based on the  plant  having
the highest flow rate and will be somewhat less for other plants.
Another unknown factor is the amount of blowdown required for the
recycle  system.   A liberal 20% blowdown is assumed.  Filtration
costs will be reduced if the allowable blowdown can be reduced.

The age of equipment and process employed  do  not  significantly
affect  costs.   No  process changes are required and significant
engineering or non-water quality  environmental  impact  problems
are not anticipated.


Float Glass Manufacturing

The typical float glass manufacturing plant may be located in any
part  of  the  country  and  has  been  built since 1960.  Annual
production  is   approximately   360,00   metric   tons.    Three
alternative  methods  of  treatment  are  discussed.   Costs  and
effluent quality are summarized in Table 11,


Alternative A - No Waste Water Treatment or control

Alternative A is the elimination of detergent usage in the  float
washer.   As  can  be seen, the waste water is of relatively high
quality and all plants presently discharge this water untreated.
         Costs.  None.

         Reduction Benefits.  Close to 100X phosphorus reduction.

Alternative B - Filtration

Alternative B uses diatomaceous earth  filtration  for  suspended
solids and oil removal.  These pollutants will be reduced to less
                              94

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                                      TABLE  11

                           WATER EFFLUENT TREATMENT COSTS
                              FIAT GLASS MANUFACTURING
                                     FLOAT GLASS
Alternative Treatment or Control Technolo-
gies:


Investment

Annual Costs:

     Capital Costs

     Depreciation

     Operating and Maintenance Cost
          {excluding energy and power costs)

     Energy and Power Costs

              Total Annual Cost


Effluent Quality:
                                          ($1,000)
Effluent Constituents
Flow

Suspended Solids

Oil

COD



Flow

Suspended Solids

Oil

COD
{I/metric ton)

(g/metric ton)

(g/fretric ton)

{g/metric ton)



(I/sec)

(mg/1)

Cmg/D

teA)




»sts)


Raw
Waste
Load
138
2
0.7
2
1.6
15
5
15
ABC
0 50 57
0 4.0 4.6
0 2.5 2.9
0 3.5 5.5
0 0.8 0.9
0 10.8 13.9

Resulting Effluent
Levels
138 138 92
2 .7 .4
0.7 .7 .7
2 .2 .2
1.6 1.6 1.1
15 5 5
555
15 15 15
D
134
11
6.7
28.4
12.5
58.6




Discharge
s


                              95

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than  5  mg/1.  This high quality effluent could be discharged or
reused in the float process as discussed in Alternative C  or  in
glass fabrication operations if they are available.

         Costs.   Incremental  investment  costs  are $50,000 and
         total annual costs are $10,800 over alternative A.

         Reduction Benefits.  Suspended solids  are  reduced  61%
         over  Alternative  A.   Additional reductions in oil are
         accomplished.


Alternative^ - Recycle to Batch and Cooling Tower

Alternative C includes recycle of filtered float washwater to the
batch and cooling tower.   Process  waste  water  pollutants  are
reduced an additional 338 below that achievable by Alternative B.
The  waste  load  recycled  to  the batch will become part of the
glass and the waste load  recycled  to  the  cooling  tower  will
constitute a portion of the cooling tower blowdown.

         Costs.   incremental  investment  costs  are  $7,000 and
         total annual costs are $3,100 over Alternative B.
                                                   process  waste
         Reduction Benefits.  Reduction of 3336 of
         water discharge over Alternative B.

Alternative^D - Total Recycle

Alternative  D  is  the  total recycle of waste water back to the
process following treatment using diatomaceous  earth  filtration
for  suspended  solids  removal and reverse osmosis for dissolved
solids  removal.   Waste  brine  is  evaporated  to  dryness  and
residual  salt  permanently  stored.   Sufficient  suspended  and
dissolved solids are removed so that the water can be reused  for
float washing.  No liquid wastes are discharged.

         Costs.   Incremental  investment  costs are $127,000 and
         total annual costs are $55,500 over Alternative A.

         Reduction Benefits.  Waste water  discharge  is  totally
         eliminated.    Reduction   of   suspended  solids,  COD,
         phosphorus and all other pollutant constituents of 100%.

About half of the float glass plants produce process waste  water
in  the  form of washwater.  Washing is not required at the other
plants and no  process  waste  water  is  produced.   Washing  is
necessary  where  practiced and cannot be eliminated on the bases
of the information gathered for this study.

No cost is associated with Alternative A.  The evidence  gathered
indicates  that  detergent  can  simply  be  eliminated  from the
process.  The cost of Alternatives C and D will depend  upon  the
quantity  of  glass  produced  and the allowable dissolved solids
                               96

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 build-up.  The typical plant is one of the largest  float  plants
 so  that the costs  should be somewhat conservative with respect to
 the entire  subcategory.   The high cost of Alternative D is the
 result of dissolved solids  removal  and  waste  brine  disposal.
 These  costs  could  be only roughly estimated since no system of
 this type is presently in operation.  Each of the alternatives is
 a separate system  and there is no benefit   to  be  derived  from
 cost phasing.

 As  discussed  in  the Development Documents the age of equipment
 and the process employed do not significantly affect  costs.   No
 process  changes   are  required and no significant engineering or
 non-water quality  environmental impact problems are anticipated.

 $olid Tempered Automotive Glass Fabrication

 The typical solid  tempered automotive glass fabrication plant may
 be  located in any  part of the country and uses process  equipment
 that  has  been  modified within the last 10 to 15 years.  Annual
 production is 3.5  million  square  meters.   Cost  and  effluent
 quality   for  the  four  treatment  alternatives  discussed  are
 summarized in Table 12.

            A -  No Waste Water Treatment or Control

 Alternative A is no waste water treatment or control.  The  waste
 water  is of relatively high quality except for suspended solids.
 At the present time, no plants treat  solid  tempered  automotive
 waste water.  Land disposal of coolant sludge is assumed, as this
 is almost universally practiced in the industry.

         costs.   None.

         Reduction Benefits.  None.

          e^B -   Coagulation-Sedimentation
Alternative  B is solids contact coagulation-sedimentation of all
process waste water, centrif ugation  of  waste  sludge  and  land
disposal of dewatered waste solids.

         Costs.   Incremental  investment  costs  are $81,000 and
         total annual costs are $24,100 over Alternative A.
         Reduction  Benefits *
         reduced 759E.
Effluent  suspended  solids   are
Alternative.C -  Filtration

Alterantive  C is oil absorptive diatomaceous earth filtration of
the effluent from Alternative B.  The spent diatomaceous earth is
also disposed of as landfill.
                                 97

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                                 TABLE 12

                     WATER EFFLUENT TREATMENT COSTS
                        FIAT GLASS MANUFACTURING
               SOLID TEMPERED AUTOMOTIVE GLASS FABRICATION
Alternative Treatment or Control Teohnolo-
gies:
Investment
Annual Costs:
Capital Costs
Depreciation
Operating and Maintenance Coats
(excluding energy and power costs)
Energy and Power Costs
Total Annual Cost
Effluent Quality:
Raw
Waste
Effluent Constituents Load
Flow (1/kq m) 49

BOD (g/&q m) ,73
Suspended Solids (g^sq m) 4.9
Oil (g/sq m) .64
Flow (I/sec) 7.9
BOD (mg/1) 15
Suspended Solids (mg/1) 100
Oil (mg/1) 13
A
0

0
0
0
0
0


($1,000)
B C
81.

6.5
4.1
11.7
1.8
24.1


149.

11.9
7.5
17.9
4.8
42.1


D
364.

29.1
18.2
53.4
25.7
126.4


Resulting Effluent
Levels
49

.73
4.9
.64
7.9
15
100
13
'49

.73
1.22
.64
7.9
15
25
13
49

.49
,24
.24
7.9
10
5
5

bO
1
CO
•H
R
&
tin
DischaTj
0
                                    98

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         Costs.  Incremental investment  costs  are  $68,000  and
         total annual costs are $18,000 over Alternative B.

         Reduction  Benefits.  Incremental reduction of suspended
         solids is 8056.  Total reductions  of  suspended  solids,
         oil and BOD are 95, 62, and 33% respectively.

Alternative. D - Total Recycle

Alternative  D  is  the  further  treatment  of the effluent from
Alternative  C  using  reverse  osmosis.   The  waste  brine   is
evaporated  and the residual salt permanently stored-  Sufficient
suspended and dissolved solids are removed so that the water  can
be  reused  in  the  manufacturing process.  No liquid wastes are
discharged.

         Cost.  Incremental investment  costs  are  $215,000  and
         total annual costs are $84,300 over Alternative C.

         Reduction Benefits.  Reduction of suspended solids, oil,
         BOD and all other pollutant constituents of 100%.

The  volume  of  water  to  be  treated  depends on the amount of
recycling practiced.  More extensive  recycling  at  the  typical
plant is representative of the better plants in this subcategory.
A  further  reduction  in  water usage may be possible but is not
assumed in the cost estimate.  For those plants  presently  using
more  water  than  the typical plant, higher cost may be required
for increase treatment cost  or  for  in-plant  modifications  to
reduce  water  usage.   The costs recorded here are representative
of an above average size plant with moderate water recycling  and
reuse  practices.    A  flow reduction of 5096 prior to the reverse
osmosis system in Alternative D is assumed.

None of the treatment methods is presently practiced in the  flat
glass   industry.    The  technology  is  transferred  from  other
industries and for this reason the cost estimates may be somewhat
rough.  This is especially true for the reverse osmosis system in
Alternative D, where many unknowns had to be assumed.   There  is
no  apparent  benefit  for  phasing  costs within an alternative;
however, where one alternative includes other  alternatives,  the
earlier alternatives may be built first.

The   age   of   equipment   and  the  process  employed  do  not
significantly affect costs.  No process changes are required  and
no  significant  engineering  or  non-water quality environmental
impact problems are anticipated.

Windshield, Fabrication

The typical windshield fabrication plant may be  located  in  any
part  of  the country and uses oil autoclaves.   Annual production
is 750,000 square meters.   Cost and effluent quality for the four
treatment alternatives discussed are summarized in Table 13.
                               99

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                                 TABLE, 13

                      WATER EFFLUENT TREATMENT COSTS
                         FIAT GLASS MANUFACTURING
                          WINDSHIELD FABRICATION
Alternative Treatment or Control Technolo-
gies

Investment
Annual Costs:
Capital Costs
Depreciation
Operating and Maintenance Costs
(excluding energy and power costs.)
Energy and Power Costs
Total Annual Cost
Effluent Quality:
Raw
Waste
Effluent Constituents Load
Flow (l/6qm) 175

Oil (gy4qm) 298
COD (g/&q m) 298

Suspended Solids (g/feq m) 4.4
Phosphorus (g^q m) .98
Flow (I/sec) 6
Oil (mg/1) 1700
COD (rag/1) 1700

Suspended Solids (rag/1) 25
Pho sphorus ( rng/1 ) 5.6
($1,000)
A
0

0
0

0
0
0



B
32.

2.6
1.6

8.
2.4
14.6


Resulting
C
115.

9.2
5.8

13.6
4.2
32.8


Effluent
D
317.

25.4
15.8

48.5
33.1
122,8



Levels
175

298
298

4.4
.98
6
1700
1700

25
5.6
175

1.76
4.9

4.4
.98
6
10
28

25
5.6
175

.88
4.9

.88
.2
6
5
28

5
1

Q)
tiO
O
03
•H
Q
§


0)
bo
•s
m
•H
o
o

                                    100

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Alternative A  - No Waste Water Treatment or Control

Alternative A is no waste water treatment or control.

         Costs.  None.

         Reduction Benefits.  None.

Alternative B •* Lamination Washwater Treatment

Alternative B is  modification  of  the  post  lamination  washer
sequence  to  provide  a continuously recycling initial hot water
rinse, oil removal by centrifugation  of  the  recirculating  hot
rinse water, recycle of oil back to the process, and treatment of
other  post  lamination  rinse  waters by gravity oil separation.
Other process waters are not treated.  Neligible waste solids are
produced .

         Costs.  Incremental investment  costs  are  $32,000  and
         total annual costs are $1U,600 over Alternative A.

         Reduction  Benefits.  Oil is reduced by 99.UJ6 and COD is
         reduced by 98.4#.

Alternative C - Filtration

Alternative C includes oil absorptive diatomaceous earth  filtra-
tion  of  all  process  waste  water in addition to the treatment
system described for Alternative B.  The spent diatomaceous earth
is disposed of  as  landfill.   Phosphorus  is  reduced  by  more
vigorous   inplant   detergent   control   and  improved  washing
techniques.

         Costs.  Incremental investment  costs  are  $83,000  and
         total annual costs are $18,200 over Alternative B.

         Reduction  Benefits.  Incremental reductions are 50$ for
         oil and 80% for suspended solids.  Total reductions  are
         99 . 7%   for  oil ,  and  80%  for  suspended  solids  and
         phosphorus.
Mt^^Stiy.6^ - Total Recycle

Alternative D is total recycle and reuse of the  water  following
reverse  osmosis  treatment  for  dissolved  solids removal.  The
waste brine is evaporated and the residual  salt  is  permanently
stored.

         Costs.   Incremental  investment  costs are $202,000 and
         the- total annual costs are $90,000 over Alternative C.

         Reduction Benefits.  Reduction of  oil,  COD,  suspended
         solids,  phosphorus and all other pollution constituents
         of 100%.
                              101

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As with the other subcategories, the volume of water treated and,
therefore, the cost of treatment is  related  to  the  amount  of
recycling that can be practiced.  Approximately the same absolute
1/sq  m  are  required at all plants, but the quantity discharged
can te reduced  by  using  recycling  washers.   Relatively  more
recycle  is  presently  practiced for windshield fabrication than
for other subcategories but it may still  be  possible  by  using
recycling  washers in all cases and by carefully controlling flow
to further reduce usage.  The  typical  plant  is  of  less  than
average  size  and  practices moderate water recycling and reuse.
Costs may be as much as U times  higher  for  the  larger  plants
because  fo  the  higher  water  volume.  A flow reduction of 33%
prior to the reverse osmosis system in Alternative D is assumed.

New plants will probably use  air  rather  than  oil  autoclaves.
This  will  reduce the waste water flow rate by approximately 23%
and eliminate the need for Alternative B treatment.

The technology for Alternatives C  and  D  was  transferred  from
other industries and is presently not practiced in the flat glass
industry.   The  cost  estimates  for  these  alternatives may be
somewhat  rough  because  of  the  unknowns  involved.   This  is
especially  true for the reverse osmosis system in Alternative D.
There  is  no  apparent  benefit  for  phasing  costs  within  an
alternative;   however,  where  one  alternative  includes  other
alternatives, the earlier alternatives may be built first.

It is possible, but not likely  that  some  modification  of  the
washers  may  be  required  to  effect  the  detergent  reduction
indicated for  Alternative  C.   No  equipment  modification  was
required at the exemplary plant where this technology is used but
it is possible that modification will be required if another type
of  washer  is  used.   Other  considerations  such as the age of
equipment or the process employed  do  not  significantly  affect
cost   and   no  significant  engineering  of  non-water  quality
environmental impact problems are anticipated.


ENERGY REQUIREMENTS OF TREATMENT AND CONTROL TECHNOLOGIES

The energy required to implement in-plant control measures  at  a
typical   flat   glass  plant  is  5  kw  or  less.   The  energy
requirements are almost entirely for pumping  to  recycle  washer
water.

The  energy  requirements of the end-of-pipe treatment technology
are  relatively  low  for   conventional   operations   such   as
coagulation-sedimentation and filtration, but are much higher for
total   recycle   systems   incorporating   reverse   osmosis  or
evaporation.   Typical  energy  requirements   for   conventional
treatment  are 45 kw or less.  The energy requirements may run as
high as 1000 kw for a total recycle system because of the  energy
required for evaporation.
                              102

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No   information  was  provided  by  the  industry relative to the
energy requirements of individual  manufacturing  plants.   Large
quantities  of  energy  are  used  in primary glass production to
produce the high temperatures  required  for  glass  melting  and
annealing  and  numerous  large  horsepower motors are needecj for
grinding and polishing in the  plate  process.   Less  energy  is
required for automotive glass fabrication.  The additional energy
required   to   implement   conventional  control  and  treatment
technologies is less than 1% of process requirements for  primary
manufacturing  and  is  estimated  to be less than 103S of process
requirements for automotive glass fabrication.

NON-KATER QUALITY ASPECTS OF TREATMENT AND CONTROL TECHNOLOGIES

Air  Pollution

There are no significant air or noise pollution problems directly
associated with the  treatment  and  control  technologies.   The
waste  waters and sludges are odorless and no nuisance conditions
result from their treatment or  handling.   Incineration  is  not
used  in the treatment technologies so no air pollution is caused
by this source.  Water vapor resulting from  the  evaporation  of
reverse osmosis brines is expected to be relatively pure.

A  non-water  quality aspect of perhaps greater significance than
air  pollution is the  high  energy  required  for  total  recycle
systems.   In  view  of  the limited availability of clean energy
sources and the air  pollution  problems  associated  with  other
energy  sources, the benefits derived from a total recycle system
should also be weighed against the  energy  required  to  operate
such a system.

Solid, Waste_ Disposal

Landfilling of properly dewatered sludges from the flat glass in-
dustry  is  an  appropriate  means  of  disposal.  The wastes are
largely inorganic  and  incineration,  composting,  or  pyrolysis
would  not  be effective in reducing their volume.  The dewatered
solids are relatively dense and they are stable when used as fill
material.   If  disposed  of  using  proper   sanitary   landfill
techniques,  solids from flat glass manufacturing should cause no
environmental problems.

With the exception of plate glass manufacturing,  the  volume  of
sludge   associated   with  the  various  control  and  treatment
technologies is relatively small.  The  lagoons  used  for  plate
glass  suspended  solids  removal  also  serve as sludge disposal
sites.  The levees are generally raised to  keep  pace  with  the
rising sediment level.  At older plate plants large areas of low-
lying  land have been filled in.  In some cases this is reclaimed
as park land by spreading topsoil over the dry sludge solids.

Three types of waste solids are produced by the treatment systems
indicated  for  the  float,  solid   tempered   automotive,   and
                           103

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windshield  manufacturing  processes.  These are  (l) coagulation-
sedimentation sludges associated with tempering waste waters, and
(2) spent diatomaceous earth, and (3)  brine  residue  associated
with   at  least  one  treatment  alternative  for  each  of  the
subcategories.  The coagulation-sedimentation sludge  is  assumed
to  te  dewatered  by  centrifuge to about 20% dry solids and the
typical volume produced ia estimated to be 0.38 cu m/day (13.5 cu
ft/day).

Spent diatomaceous earth has an  estimated  moisture  content  of
8556, but is dry to the touch.  This material is stable and should
be  suitable  for landfill.  Estimated production of diatomaceous
earth waste is less than 0.23 cu m/day (8 cu ft/day) for each  of
the subcategories.

The  salt residue that will be produced by a total recycle system
will present the biggest disposal  problem.   To  prevent  ground
water  contamination*  it  must  be  permanently  stored in lined
basins.  Only as much water as will evaporate can be allowed into
the basin*  The land used for salt storage  will  be  permanently
spoiled.    The  salt  residue  produced  by  the  tempering  and
laminating processes is conservatively estimated to  be  0,56  cu
m/day  (20 cu ft/day).  Salt storage costs are directly related to
the cost of land and the type of lining used.

The  cost  for  hauling  the  coagulation sludge and diatomacecus
earth to landfill, assuming a commercial disposal firm  is  used,
is $60 to $100 a month.  Disposal costs are variable depending on
the equipment used and distance to the disposal site.
                              104

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                           SECTION  IX

     EFFLUENT  REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
    THE BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
                 EFFLUENT LIMITATIONS GUIDELINES

 INTRODUCTION

 The effluent  limitations that must be achieved July 1, 1977 are
 to  specify the degree of effluent   reduction  attainable  through
 the application  of  the  Best  practicable  control  Technology
 Currently  Available.   Best   Practicable   Control   Technology
 Currently  Available  is  generally based upon the average of the
 best existing performance by plants of various sizes,  ages,  and
 unit  processes  within  the  industrial category or subcategory.
 This average is not based upon a broad range of plants within the
 flat glass industry, but based upon performance  levels  achieved
 by  exemplary plants.

 Consideration must also be given to;

    a.   The total cost of application of technology in relation
         to the effluent reduction  benefits to be achieved from
         such application;

    t.   the size and age of equipment and facilities involved;

    c.   the processes employed;

    d.   the engineering aspects of the application of various
         types of control techniques;

    e.   process changes; and

    f.   non-water quality environmental impact (including energy
         requirements).

Also, Best Practicable Control Technology Currently Available em-
phasizes  treatment  facilities  at  the  end  of a manufacturing
process, but also includes the control  technologies  within  the
process  itself  when  the  latter  are  considered  to be normal
practice within an industry.

A further consideration is the degree of economic and engineering
reliability which must be established for the  technology  to  be
"currently  available".   As   a result of demonstration projects,
pilot plants,  and general use, there must exist a high degree  of
confidence  in the engineering and economic practicability of the
technology at the time of commencement of construction or instal-
lation of the control facilities.
EFFLUENT REDUCTION ATTAINABLE THROUGH  THE  APPLICATION
PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
OF  BEST
                             105

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Based  on  the information contained in Sections III through 'VIII
of this document, a determination has been made of the degree  of
effluent reduction attainable through the application of the Best
Practicable  Control  Technology Currently Available for the flat
glass segment of the glass manufacturing category.  The  effluent
reductions are summarized here.

Suspended golids

A  principal  pollutant  constituent  in  waste  waters  from the
manufacture of plate glass and the fabrication of solid  tempered
automotive  glass  is  suspended  solids.   Application  of  this
technology will reduce suspended solids levels by 99.8% for plate
glass manufacturing and 75% for solid tempered  automotive  glass
fabrication.   The  low percentage for automotive tempering is an
indication of the high quality of the raw waste water.

Suspended  solids  will  not  be  significantly  reduced  by  the
application   of   this   control   technology   to  float  glass
manufacturing and to windshield fabrication waste waters.
At least trace amounts of oil are present in all flat glass waste
waters with the highest concentration resulting  from  windshield
fabrication.   This  control technology will reduce oil levels in
windshield fabrication waste waters by 99,4%, but will not effect
significant oil removal for the other subcategories,

Oxygen Demanding Materials

Oxygen demand in the flat glass industry is related  to  the  oil
content  of  the  waste water.  COD levels will be reduced 90% in
plate glass and 98% in windshield waste waters using this control
technology.  The BOD or COD for the other subcategories will  not
be  reduced,  but  the  levels  are  already  low by conventional
standards .

ES

With the exception of plate glass manufacturing, the  pH  of  the
flat  glass  waste waters falls within the accepted range of 6 to
9.  In some cases, raw plate glass waste  water  may  have  a  pH
level   above   9,  but  neutralization  is  already  universally
practiced where necessary.

Total Phosphorus

Some phosphorus may be present  in  float  glass  and  windshield
fabrication  waste  waters  as a result of detergent usage.  This
control  technology  eliminates  detergent  usage  in  the  float
process,  but  no  treatment  or control is applied to windshield
fabrication wastewaters.
                             106

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 Temperature

 Process   waste   waters   from  the   float   and  automotive   glass
 fabrication  subcategories   may show  some  temperature increase
 because  of  heated  washwater requirements.    Application   of  this
 control   technology  will   not  result in  significant temperature
 reduction.

 P-issQlved_r Solids

 Dissolved solids increase somewhat  as a result  of   all  of   the
 glass  manufacturing  processes.  The average typical increase is
 about  100 mg/1.  High dissolved  solids   in the process water
 cannot  be  tolerated because  almost  all of the water is used for
 washing  and high dissolved  solids leave a  residue on   the  glass.
 For  this reason, flat glass process waste  water will  always be of
 high  quality  with   respect   to  dissolved solids.   This control
 technology  does  not reduce  dissolved  solids.
IDENTIFICATION  OF  THE  BEST  PRACTICABLE
CURRENTLY AVAILABLE
CONTROL   TECHNOLOGY
In-plant  control measures as well as end-of-pipe treatment tech-
niques  contribute  to  the  best  pollution  control  technology
currently   available,   although   emphasis  is  on  end-of-pipe
treatment.  Water recycle and reuse, although not  a  significant
factor  in  this technology, will tend to reduce the cost of end-
of-pipe treatment facilities.

The Best Pollution Control Technology Currently Available for the
subcategories of the flat glass  industry  is  summarized  below.
Recommended effluent limitations are summarized in Table 14.  The
limitations  are expressed in grams or kilograms of pollutant per
metric ton or 1000 square meters of product.   These  limitations
are fcoth daily maximums and monthly averages except where noted.

Sheet Glass.Manufacturing

No process waste water results from the sheet glass manufacturing
process,  therefore,  no waste water or waste load should be dis-
charged.

Rolled Glass Manufacturing

No  process  waste  water   results   from   the   rolled   glass
manufacturing  process,  therefore,  no waste water or waste load
should be discharged.

Plate Glass -Manufacturing

The control technology is partition of existing one-cell  lagoons
into two cells in series with provision for polyelectrolyte addi-
tion at the entrance to each cell.   This is to provide more effi-
cient  coagulation  and to reduce the effects of short circuiting
                            107

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                                      TABLE  14
                RECOMMENDED DAILY AVERAGE EFFLUENT LIMITATIONS USING
               BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Sheet Glass

Rolled Glass

Plate Glass
  kg/metric ton
  Ib/short ton

Float Glass
   g/metric ton
  Ih/short ton

Solid Tempered
Automotive Glass
   g/sq m
  lb/1000 sq ft

Windshields
   g/sq m
  lb/1000 sq ft
                   Suspended
                     Solids
                   Oil
                Total
              Phosphorus
        No waste water discharge

        No waste water discharge
2.76(1.38)*
5.52(2.76)*
2.00
0.004
1.95(1.22)*
0.40(0.25)*
4.40
0.90
1.40
0.0028
0.64
0.13
1.76
0.36
0.05
0.0001
1.07
0.22
                                  6-9
6-9
                 6-9
6-9
*  Figures in parenthesis are monthly average effluent limitations
                          108

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and, wind action on sedimentation.  The monthly  average  effluent
limitations  for  suspended .  solids  are  1.38 kg/metric  ton  (2.76
Ib/short ton); and a pH of between 6.0 and  9.0.

Float .Glass Manufacturing

The control technology is elimination of  detergent usage from the
float washing process.  Effluent limitations for suspended solids
are 2 g/metric ton (0.0040 Ib/short ton) ; for oil, l.UO  g/metric
ton   (0.0028  Ib/short  ton); for total phosphorus, 0.05 g/metric
ton (0.0001 Ib/short ton, and; pH of between 6.0 and 9.0.

Solid Tempered Automotive Glass Fabrication

The  control  technology  is  coagulation-sedimentation  of   all
process  waste  waters  with  land  disposal  of  dewatered waste
solids.  Effluent limitations for suspended solids are 1.22  g/sq
m  (0.25  lb/1000  sq  ft); for oil,  0.64 g/sq m (0.13 lb/1000 sq
ft); and a pH of between 6.0 and 9.0.

Windshield Fabrication

The control technology is  modification   of  the  post-lamination
washer  sequence  to provide a continuously recycling initial hot
water rinse, oil removal by centrifugation of  the  recirculating
hot  rinse  water,  recycle  of  oil  back  to  the  process, and
treatment of other postlamination rinse  waters  by  gravity  oil
separation.   Negligible  waste  solids  are  produced.  Effluent
limitations for suspended solids are 4.4  g/sq m (0.9  lb/1000  sq
ft);  for  oil,  1.76  g/sq  m  (0.36  lb/1000  sq ft); for total
phosphorus, 1.07 g/sq m (0.22 lb/1000 sq ft) ; and a pH of between
6.0 and 9.0.
                                            PRACTICABLE
CONTROL
RATIONALE  FOR  THE  SELECTION  OF   BEST
TECHNOLOGY CURRENTLY AVAILABLE

Engineering Aspects of Application

In  all  cases,  this  control technology has been applied in the
glass industry or in another industry where  the  characteristics
of  the  water treated are sufficiently similar to provide a high
degree of confidence that the technology can  be  transferred  to
the glass industry.
The  derivation  and  rationale  for  selection  of  the  control
technology are described in detail in Sections V and VII.   These
may te briefly summarized as follows:

Plate, Glass

Existing  treatment  of  plate  glass  waste  waters is uniformly
inadequate  and  must  be  upgraded.   The   recommended   lagoon
modifications and the resulting effluent limitations are based on
company  experience  and  engineering judgement.  The recommended
effluent concentrations are being achieved part of  the  time  in
                             109

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existing  plate  glass lagoon systems and there is no evidence to
indicate that these levels can not be achieved using the proposed
technology.

Float Glass Manufacturing -

Elimination of detergents from the float washer will result in  a
high  quality  waste water suitable for discharge without further
treatment.  The detergent wash has  already  been  eliminated  at
most  plants  and there is no evidence to indicate elimination of
detergents is detrimental to the  product  or  the  manufacturing
process,  of the six plants that presently wash float glass* four
have already eliminated detergents.

Solid Tempered Automotive Gj.ass Fabrication  -

None  of  the  plants  studied  presently  treat  solid  tempered
automotive waste water.  Treatment for suspended  solids  removal
is  required  prior  to  discharge.  The recommended coagulation-
sedimentation technology is commonly used for removing  suspended
solids  from  both water and waste water.  Company experience and
engineering judgement indicate that this treatment technology and
the resulting effluent limitations can  be  successfully  applied
for solid tempered automotive waste water treatment.

Windshield Fabrication -

One   plant  is  presently  achieving  t he  recommended  e f fluent
limitations using the  technology  indicated  for  treating  post
lamination  wash  water.  It is also possible to achieve the same
effluent quality using dissolved air  floatation  but  at  higher
cost.   The  equipment for either system is readily available and
can he installed on existing washers without any interruption  of
normal operations.


Total Cost of Applicatj.QQ

Eased  on  the  information  presented  in  Section  VIII of this
document,  the  industry  as  a  whole  would  have   to   invest
approximately   $900,000  to  achieve  the  effluent  limitations
prescribed herein.  The increased annual costs of  applying  this
control technology are approximately $345,000 for the industry.

Sj.ze and, Age, of Equipment

The   size   of   plants  within  the  same  subcategory  is  not
sufficiently different to  substantiate  differences  in  control
technology  based  on  size.   All  glass plants are continuously
modernized so that age  of  equipment  and  facilities  does  not
provide  a  basis  for differentiation in the application of this
control technology.

Processes Employed
                            no

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All plants in a given subcategory use very similar  manufacturing
processes  and  produce  similar  waste  water  discharges.   The
control technology for a given subcategory is compatible with all
of  the  manufacturing   processes   presently   used   in   that
subcategory.

Process changes

A  minor  process  change  is required in one subcategory for the
implementation of this technology,  it will be necessary for  the
plants  in  the windshield fabrication subcategory that are still
using an initial detergent wash as part  of  the  post-lamination
washing  sequence  to eliminate this wash in favor of a recycling
hot water rinse.  As far as is known, this  can  be  accomplished
without any additional equipment by simply eliminating phosphorus
from  the  first  stage washer.  This technology is presently em-
ployed by a number of windshield fabrication plants.

Major changes in the production process are not anticipated.   It
should  be  noted,  however, that minor process changes to adjust
for automobile model changes are required yearly  for  automotive
glass  fabricating  plants.  These generally do not significantly
affect waste water volumes or characteristics.   This  technology
can  te  applied so that upsets and other fluctuations in process
operations can be accommodated  without  exceeding  the  effluent
limitations.

Non-Kater Quality Environmental Impact

There  is no evidence that application of this control technology
will result in any unusual air pollution or solid waste  disposal
problems,  either  in  kind  or magnitude.   The costs of avoiding
problems in these areas are not excessive.   The  energy  required
to   apply  this  control  technology  represents  only  a  small
increment  of  the  present  total  energy  requirements  of  the
industry.
                              m

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                            SECTION X

     EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
      THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
                 EFFLUENT LIMITATIONS GUIDELINES
INTRODUCTION

The  effluent limitations that must be achieved July 1, 1983, are
to specify the degree of effluent  reduction  attainable  through
the  application  of  the  Best Available Technology Economically
Achievable.  This control technology is not based upon an average
of the best performance within an  industrial  category,  but  is
determined  by  identifying  the  very best control and treatment
technology employed by a specific  plant  within  the  industrial
category or subcategory, or where it is readily transferable from
one industry process to another.

Consideration must also be given to:
    a.



    b.

    c,

    d.


    e.

    f.
The total cost of application of this control technology
in relation to the effluent reduction benefits to be
achieved from such application;

the size and age of equipment and facilities involved;

the processes employed;

the engineering aspects of the application of this
control technology;

process changes; and

non-water quality environmental impact (including energy
requirements).
Best  Available Technology Economically Achievable also considers
the availability of in-process controls as  well  as  control  or
additional   end-of-pipe   treatment  techniques.   This  control
technology is the highest degree that has been  achieved  or  has
been demonstrated to be capable of being designed for plant scale
operation up to and including "no discharge11 of pollutants.

Although economic factors are considered in this development, the
costs  for  this  level of control are intended to be the top-of-
the-line of current technology subject to limitations imposed  by
economic  and  engineering  feasibility.   However,  this control
technology may be  characterized  by  some  technical  risk  with
respect  to  performance  and with respect to certainty of costs.
Therefore,  this  control   technology   may   necessitate   some
industrially sponsored development work prior to its application.
                            113

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EFFLUENT  REDUCTION  ATTAINABLE  THROUGH  THE APPLICATION OF BEST
AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE

Based on the information contained in Sections III  through  VIII
of  this document, a determination has been made of the degree of
effluent reduction attainable through the application of the Best
Available Technology Economically Achievable.   No  discharge  is
attainable  for  the  sheet  and rolled glass subcategories as is
indicated in section IX.  The effluent reductions attainable  for
the ether subcategories are summarized here.

Suspended Solids

Suspended  solids are reduced by more than 95% for the plate, and
solid tempered automotive glass subcategories by this technology.
The incremental increase over the levels achieved using the  Best
Practicable  control  Technology  Currently  Available  is 67% or
greater.   This  technology  effects  a  67%   suspended   solids
reduction  in  the  float waste water and an 80% suspended solids
reduction in windshield lamination waste water.  The low  percent
reduction  in  these  cases  is  a  result of the relatively high
quality of the raw waste water,

SU

This  technology  reduces  oil  discharged  from  the  windshield
fabrication  process  by  98%,  and from the solid tempered glass
process by 62%, and also from the float process.  The incremental
increase for windshield fabrication over the application  of  the
Best Practicable Pollution Control Technology Currently Available
is  50%.   The  lower  reduction  achieved for the solid tempered
process is due to the low oil  concentration  in  the  raw  waste
water.   The  best  available  technology economically achievable
will further reduce oil discharged from the float  process  below
detectable limits.

Qyygeti, Demanding Materials

The COD discharged by the plate process is reduced by 98% or more
with this technology, but no reduction is achieved for windshield
fabrication  waste  waters.   The  incremental  increase  in  COD
removal over  the  level  achieved  using  the  Best  Practicable
Control Technology Currently Available is 80% for the plate glass
process.

This  technology  reduces  the  BOD  in solid tempered automotive
glass waste water by only 33% because the raw waste water  is  of
high quality.

Tot a 3. Phosphorus

With   this   technology,  total  phosphorus  discharged  by  the
windshield fabrication process is reduced 80%.  Phosphorus is not
                              114

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 a significant  constituent   in  plate   glass  and  solid  tempered
 automotive  glass  waste waters.

 Other Pollutant Constituents

 Temperature and  dissolved  solids,  which  are  discussed in section
 IX,  are not significantly reduced by  this technology.

 IDENTIFICATION OF BEST AVAILABLE CONTROL  TECHNOLOGY  ECONOMICALLY
 ACHIEVABLE

 Both  in-plant controls  and  end-of-pipe treatment   technology
 constitutes the   Best  Available   Pollution  control   Technology
 Economically Achievable.  This  technology is  summarized below  and
 recommended daily average   effluent  limitations   are listed in
 Table 15.   The limitations are  expressed  in grants or kilograms of
 pollutant per  metric ton or 1000 square meters of product.

 P3.ate Glass Manufacturing

 The  control technology is improvement  of  existing lagoon   systems
 as   described  in  Section IX,  return of 8036 of the lagoon  effluent
 to the grinding operation, sand filtration of the remaining  2036,
 and   return of   the  filter  backwash to the head  of  the lagoon
 system.  Effluent limitations   for  suspended  solids   are  0.045
 kg/metric   ton (0.09 Ib/short ton)   and for COD are 0.09 kg/metric
 ton  (0.18 Ib/short ton).

 Float Glass Manufacturing

 The  control technology is elimination  of  detergent usage  from  the
 float washing  process as described  in  Section IX followed by   oil
 absorptive  diatomaceous  earth filtration.   waste   solids   are
 disposed of to landfill.   Effluent   limitations  for  suspended
 solids are 0.70 g/kkg  (0.0014 Ib/ton);  for oil are  1*40 g/kkg
 (0.0028 Ib/ton),  for phosphorous are 0.05  g/kkg  (0.0001  Ib/ton),
 and  a pH between  6.0 and 9.0,

 Soj.id Tempered Automotive Glass Fabrication

 The    control  technology  is   coagulation-sedimentation   of   all
 process waste  waters as described in Section IX followed   by   oil
 absorptive  diatomaceous  earth  filtration.   Waste  solids   are
 disposed of to landfill.   Effluent   limitations  for  suspended
 solids  and oil  are 0.24 g/sq m (0.05 lb/1000 sg ft) and for  EOD
 are  0.49 g/sq  m (0.1 lb/ 1000 sq ft).

Windshield  Fabrication

 The control technology is recycle of the   post-lamination  washer
 initial  hot  water rinse and gravity  separation of the remaining
post-lamination rinse waters as described  in Section IX, oil  ab-
 sorptive diatomaceous earth filtration of  the total process waste
water  discharge,   and  reduction  of   detergent usage.  Effluent
                             115

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                                      TABLE  15
                RECOMMENDED DAILY AVERAGE EFFLUENT LIMITATIONS USING
              BEST AVAILABLE CONTROL TECHNOLOGY ECONOMICALLY ACHIEVABLE
Sheet Glass

Rolled Glass

Plate Glass
  kg/^netric ton
  Ib/short

Float Glass
   g/ftetric ton
  Ib/short ton

Solid Tempered
Automotive Glass
   g/sq m
  lb/1000 sq ft

Windshields
   g/sq m
  lb/1000 sq ft
                   Suspended
                     Solids
                 Oil
                Total
              Phosphorus
      No waste water discharge

      No waste water discharge
0.045
0.090
0.70
0.0014
0.24
0.05
0.88
0.18
1.40
0.0028
0.49
0.10
1.76
'0.36
0.05
0.0001
0.30
0.06
                                  6-9
6-9
                 6-9
6-9
                              116

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 limitations for suspended  solids and oil are  0.88  g/sq  m   (0.18
 lb/   1000  sq  ft), for COD  tt.9 g/sq m  (1.0 lb/1000  sq ft), and  for
 phosphorus are 0,2 g/sq m  (0.04 lb/1000 sq ft).
RATIONALE FOR THE SELECTION OF BEST AVAILABLE TECHNOLOGY ECONOMI-
CALLY ACHIEVABLE

Total Cost_of Application

Based upon the information contained  in  Section  VIII  of  this
document,  the  industry as a whole would have to invest up to an
estimated  maximum  of  $3,200,000  to   achieve   the   effluent
limitations prescribed herein.  The increased annual costs to the
industry would be approximately $1,000,000.

Size_and_Age of Equipment and Facilities

As discussed in Section IX, differences in size and age of equip-
ment  and  facilities  in  the industry do not play a significant
role in the application of this control technology.

Processes^Employed

The manufacturing processes employed within each  subcategory  of
the  industry  are basically similar and the differences will not
influence the applicability of this control technology.

Engineering Aspects of Application

This level of technology is not achieved by any plants in the in-
dustry at the present time.  However, as indicated in Section VII
of this document, there is a high degree of confidence that  this
technology  can  be  implemented  in  the  industry by 1983.  The
treatment and systems are now used in other industries  and  this
technology can be readily transferred to the flat glass industry.
The   derivation  and  rational  for  selection  of  the  control
technology are described in detail in Section VII.  These may  be
briefly summarized as follows:

Plate Glas s Manufacturing

Rapid  sand  filtration is a thoroughly proven technology that is
used extensively  in  the  water  treatment  industry.    Effluent
concentrations  below  the  proposed effluent limits are commonly
achieved.  The lagoon effluent should  be  suitable  for  recycle
because  the  suspended  solids level is in most cases lower than
the concentration of the raw river water presently being used.

Float Glass Manufacturing

Process waste water pollutants in float glass  washwater  can  be
further   reduced   by   diatomaceous   earth   filtration.    The
limitations allow a discharge after filtration  but  some  plants
                             177

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may be able to recycle this water as batch or cooling water make-
up,    with   the  exception  of  temperature,  the  waste  water
characteristics are not significantly  different  from  the  city
water presently being used for this purpose,

solid Tempered Autmgt;j.ve Glass and Windshield Fabrication


Oil  absorbtive  diatomaceous  earth filtration is the additional
treatment technology recommended  for  both  the  solid  tempered
automotive   and   windshield  fabrication  subcategories.   This
technology is commonly used to remove oil  and  suspended  solids
from  boiler water condensate and effluent concentrations of less
than 5 mg/1 are readily achievable for both parameters.  There is
no evidence to indicate that this technology can not  be  applied
to waste water treatment in the glass industry.

process Changes

Only  one  process change is effected by this control technology.
Reduction  of  detergent  usage  in  the  windshield  fabrication
process  is  required.   Although  the exemplary plant upon which
this technology is based required no  equipment  modification  to
achieve the technology, it is possible, but not anticipated, that
equipment   modification   may   be  required  in  other  plants.
Recycling of water is not required by the technology, but  it  is
likely  plants  will  reduce  water  usage to a minimum to reduce
treatment costs.

Non-Vsater_0.ualitY Environmental. Aspects

The application of this control technology will  not  create  any
new   air   or   land   pollution   problems,  but  will  require
approximately 2.5 times more energy  than  is  required  for  the
application  of the Best Practicable Control Technology Currently
Available.  This is still estimated to be less than  10%  of  the
energy required for the manufacturing process.
                              118

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                           SECTION XI

                NEW SOURCE PERFORMANCE STANDARDS
The  term  "new  source"  is  defined  to  mean  "any source, the
construction of which is commenced after the publication  of  the
proposed  regulations prescribing a standard of performance." New
sources from the sheet, rolled, float, and solid  tempered  auto-
motive  glass  and  windshield  subcategories  should achieve the
effluent  limitations  prescribed  as  attainable   through   the
application   of   the  Best  Available  Technology  Economically
Achievable.   This  technology  reduces  the   concentration   of
pollutant  constituents  to low levels and no other technology is
indicated that will further reduce these levels by virtue of  new
construction.

New sources in the plate glass subcategory should achieve no dis-
charge  of  process  waste  waters  to  navigable  waters.   This
regulation will most probably prevent the construction of any new
plate glass plants.  This type of  glass  Can  be  produced  more
economically  and  with  almost  no  water pollution by the float
process with  the  technologies  recommended  in  this  document.
Owing  to  the  high  operating costs associated with plate glass
production, new source construction would be very  unlikely  even
without effluent limitations.
                              119

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                           SECTION XII

                         ACKNOWLEDGMENTS

The  Environmental  Protection  Agency  wishes to acknowledge the
contributions  to  this  project  by  Sverdrup   S   Parcel   and
Associates,  Inc.,  St.  Louis, Missouri.  The work at Sverdrup &
Parcel was performed under the direction of  Dr.  H.G.  Schwartz,
Jr.,  Project  Executive; Richard C. Vedder, Project Manager; and
assisted by Troy Kniffin.

Appreciation is extended to the many people in the flat glass in-
dustry who cooperated in providing information and data.

Special mention is made of the following company  representatives
who  gave  of  their  time in developing the information for this
document: Mr. Raymond Smith of ASG Industries, Mr.  Paul  Schmitt
of  CE Glass, Mr. Victor Sussman and Mr. Kenneth Bradford of Ford
Motor Company, Mr. Henry Walker  of  Fourco  Glass  Company,  Mr.
Richard  Alonzo  of  Guardian Industries, Mr. Werner Ganz and Mr.
William Hupp of Libbey-Owens-Ford Company,  Mr.  James  Destefano
and Mr. James Elliott of PPG Industries, Mr. Charles Stevenson of
Safelite  Industries,  and  Mr. Dan Baraszu of Shatterproof Glass
Corporation.

Appreciation  is  expressed  to  those   in   the   Environmental
Protection Agency who assisted in the performance of the project:
Robert Dellinger, Frances Hansborough, Jane Mitchell, John Riley,
George  Webster,  Ernst Hall, Arthur Mallon, Martin Knittel, John
Insigna, and Edward Kimball.
                               121

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                          SECTION  XIII

                           REFERENCES
 1 - Eetz Handbook of Industrial Water Conditioning ,  Bet z
         Laboratories, Philadelphia, Pa. ,  1962.

 2. Dietz, A. G. H., Engineering Laminates, John Wiley 6 -Sons,
         New York, 1949.

 3- Handbook of Chemistry and Physics -  38th Edition, Chemical
        ~Rubber~Publishing Co., P. 503 S~*5337 1956?            *.

 4. Hardenbergh, W. A. and Rodie, E. B. , Water .Supply and  Waste
         Disposal, international Textbook, Scranton, Pa. ,  19637

 5 • Industrial Waste Study Report! ^Flat Glass, Cement. Lime,
                     Asbestos Industries ,  report to  Environmental
         Protection Agency by Sverdrup & Parcel and Associates,
         Inc., 1971.

 6 . Jphns-Manyille _Techaical_Data_. Sheet No_- FF-214 , New Yor k

 7. Lynam, B. , Ettelt, G., and McAloon, T. , "Tertiary Treatment
         at Metro Chicago by Means of Rapid Sand Filtration and
         Microstrainers" , Journal Water Pollution control
                     £ir No7 2, p"7 247, 1969.
 8 • Methods for Chemical_AnaXvsis of Water and Wastes, Environ-
         mental Protection Agency, National Environmental
         Research Center, Analytical Quality Control Laboratory,
         Cincinnati, Ohio, 1971.

 9* Patterson, W. L. and Banker, R. F., Estimating Costs and
         Manpower Requirement s for Conventional Waste wa teg-
         Treatment Facilities, Black and Veatch, Consulting
         Engineers for the Office of Research and Monitoring,
         Environmental Protection Agency, 1971.

10. Fersson, R, , Flat Glass Technology, Butterworths , London, 1969

11. Porter, J. W., Hopkins, A. N. , Fisher, W. L. , "An Economic
         and Engineering Analysis of Municipal Waste water
         Renovation", Water^^gO, No. 64, P. 246, 1968.
12. Probstein, R. F., "Desalinization", American Scientist ,
         Society of Sigma Xi, New Haven, Conn., May - June, 1973.

13 . Sewage Treatment Plant and Sewer Construction Cost Indexes ,
       ~ Environmental Protection Agency, Office of Water
         Programs Operations, Municipal Waste water Systems
         Division, Evaluation and Resource Control Branch.
                             123

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14. Shand, E. B.f Glass Engineerincr Handbook, McGraw-Hill,
         New York, 1958,

15. Smith, Robert, Cost of Conventional and Advanced .Treatment
         2l Waste water. Federal Water Pollution Control
         Administration, U.S. Department of the Interior, 1968.

16. Smith, Robert and McMichael, Walter F., Cost and Performance
         Estimates for Tertiary Waste.waterJEreating .Processes,
         Federal Water pollution Control Administration, U.S.
         Department of the Interior, 1969,

17• Standard industrial Classification Manual, Office of
         Management and Budget, U.S. Government Printing Office,
         Washington, D.C., P. 136 - 138, 1972.

18. Standard tflethods^for'the Examination of Water a_nd .£aste_water,
         13th Edition, American Public Health Association,
         Washington, D.C., 1971.

19. ttater Treatment Plant Design, American Water works Association,
         New York, 1969.
                              124

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                           SECTION XIV

                            GLOSSARY
Act

The Federal Water Pollution Control Act Amendments of 1972.

Annealing

Prevention or removal of  objectionable  stresses  by  controlled
cooling from a suitable temperature.

Batch

The  raw materials, properly proportioned and mixed, for delivery
to the furnace.

Slowdown

A discharge from a system, designed to prevent a buildup of  some
material, as in a boiler to control dissolved solids.

Category and Subcategory

Divisions  of  a  particular industry which pose different traits
which affect water quality and treatability.

Cooling Water

Water used primarily for dissipation of  process  heat.   Can  be
both contact or non-contact, and is usually the latter.

Gullet

Broken  glass  generated  in  the  manufacturing  or  fabricating
processes.

Diatomaceous Earth

The skeletal remains of tiny aquatic plants, commonly used  as  a
filter  medium to remove suspended solids from fluids.   Specially
treated diatomaceous earth can be obtained  for  the  removal  of
emulsified oil from water.

Fabrication

Used  in this report in conjunction with processes which use flat
glass as the raw material,  such as windshield laminating.
                             125

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Material, animal in origin, used in polishing pads  for  applying
the  polishing  medium  (iron  oxide  or  cerium oxide slurry) in
polishing plate glass.

Laminating

A process of constructing in layers to  produce  a  product  with
composite  properties  which  are  different  from  those  of the
components, as in automotive windshields which are made  shatter-
resistant by laminating.

Lap

A  large  iron  grinding  wheel used in conjunction with a graded
sand slurry for grinding plate glass.
A long tunnel-shaped  oven  for  annealing  glass  by  continuous
passage.
Used in this report in conjunction with the primary float, plate,
sheet and rolled processes*

New Source

Any  building,  structure,  facility,  or installation from which
there  is  or  may  be  a  discharge  of  pollutants  and   whose
construction  is  commenced after the publication of the proposed
regulations.

Process Water

Any water which comes into direct contact with  the  intermediate
or  final  product.   Includes contact cooling, washing, grinding
and polishing, etc.
A light grinding or sanding process  for  removal  of  the  sharp
edges  produced  by cutting of the glass, primarily for safety in
handling.

Supernatant

The layer floating above the surface of a layer of solids, as the
liquid phase in a solids-separating centrifuge.
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 surface Waters
Navigable waters.  The waters of the United States including  the
territorial seas.
Tempered Glass
Glass that has been rapidly cooled from near the softening point,
under  rigorous  control,  to increase its mechanical and thermal
endurance.
Washer
A process device used for water cleaning of the product.
waste_Water
Process water or contact cooling water which has become  contami-
nated with process waste and may no longer be usable.
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                        CONVERSION TABLE

MULTIPLY  (ENGLISH UNITS)         by       TO OBTAIN  (METRIC UNITS)

    ENGLISH UNIT             CONVERSION         METRIC UNIT
acre                         0.405
acre - feet               1233.5
British Thermal Unit         0.252
BTU/short ton   -             0.278

BTU/square foot              2.71

feet                         0.3048
gallons                      3.785
gallons/minute               0.0631
gallons/1000 square feet     0.0407
gallons/short ton            4.17
horsepower                   0.74557
inches                       2.54
pounds                       0.454
pounds/1000 square feet      0.00489
pounds/short ton             0.5
million gallons/day     33785.0
square feet                  0.0929
tons  (short)                 0.907
hectares
cubic meters
kilogram - calories
kilogram - calories/
 metric ton
kilogram - calories/
 square meter
meters
liters
liters/second
liters/square meter
liters/metric ton
kilowatts
centimeters
kilograms
kilograms/square meter
kilograms/metric ton
cubic meters/day
square meters
metric tons
(1000 kilograms or kkg)
                                128
                                          *U.S. GOVERNMENT PRINTING OFFICE:1974 S46-318/334  1-3

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