Development Document for Effluent Limitations Guideljngp
and New Source Performance Standards for the

PLYWOOD,  HARDBOARD,

AND  WOOD  PRESERVING

Segment of the Timber

Products Processing

Point Source Category
               APRIL 1974
          U'S ENVIRONMENTAL PROTECTION AGENCY
     *          Washington, D.C. 20460

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'

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                   DEVELOPMENT DOCUMENT

                             for

              EFFLUENT LIMITATIONS GUIDELINES

                             and

             NEW SOURCE PERFORMANCE STANDARDS

                           for the

      PLYWOOD, HARDBOARD AND WOOD PRESERVING SEGMENT
      OF THE TIMBER  PRODUCTS PROCESSING POINT  SOURCE
                          CATEGORY
                      Russell E. Train
                        Administrator

                        Roger Strelow
  Acting Assistant  Administrator for Air  & Water Programs
                         Allen Cywin
          Director,  Effluent Guidelines  Division

                     Richard E. Williams
                       Project Officer

                         April, 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.C. 20402 - Price $3.30

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I
                                     ABSTRACT
                  A study was made of the plywood, hardboard and wood pre-
         serving segment of the timber products  processing  point  source
         category.  The purpose of the study was to develop information to
         assist  the Agency in establishing effluent limitation guidelines
         for existing sources, new source performance standards  and  pre-
         treatment  standards as required by Sections 304, 306, and 307 of
         the Federal Water Pollution Control Act Amendments of 1972.

                  The plywood, hardboard and wood  preserving  segment  of
         the  industry was divided into 8 subcategories based primarily on
         distinctions generated from differences in the  type  of  product
         manufactured   and   the   specific   processes  involved.   Best
         practicable control technology currently available for six of the
         subcategories was determined to be no .discharge of process  waste
         water pollutants into navigable waters.  These subcategories are:
         Barking,   Veneer,   Plywood,   Hardboard  •*•  Dry  Process,  Wood
         Preserving, and Wood Preserving - Boultonizing.   Discharges  are
         allowed   for  hydraulic  barking  operations  and  direct  steam
         conditioning   in   the    veneer    manufacturing    operations.
         Quantitative  limitations  are  determined  for the Hardboard-Wet
         Process and the Wood Preserving-Steam subcategories.

                  Best available technology economically  achievable  will
         result  in  the  elimination of discharge the barking subcategory
         and the veneer subcategory.

                  The   new   source   performance   standards   for   six
         subcategories  is  no discharge of process waste water pollutants
         into  navigable  waters.   For   the   remaining   subcategories,
         limitations   are   equivalent   to   the  levels  achievable  by
         application  of  the  best  available   technology   economically
         achievable.   A discharge is allowed for effluents from hydraulic
         barking operations.

             The new source performance standards for six subcategories is
         no discharge of process waste  water  pollutants  into  navigable
         waters.    For   the  remaining  subcategories,  limitations  are
         equivalent to the levels achievable by application  of  the  best
         available  technology   economically  achievable.   A discharge is
         allowed for effluents from hydraulic barking operations.

             Pretreatment standards allow the discharge of  process  waste
         water   from  these  eight  subcategories  into  publicaly  owned
         treatment works per 40  CFR Part 128, except for Section 128.133.

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                             CONTENTS


Section                                                         Page

I              Conclusions                                        1

II             Recommendations                                    3

III            Intro duction                                       9
                 Purpose and Authority                            9
                 Basis for Guidelines Development                10
                 General Description of the Industry             12
                 Barking                                         12
                 Veneer and Plywood                              14
                 Hardboard                                       28
                 Wood Preserving                                 51

IV             Industry Subcategorization                        61
                 Introduction                                    61
                 Factors in Industry Sufccategorization           61
                 Summary of Subcategorization                    66

V              Water Use and Waste Characterization              69
                 Log Barking                                     69
                 Veneer and Plywood                              69
                 Hardboard - Dry Process                         86
                 Hardboard - Wet Process                         93
                 Wood Preserving                                113

VI             Selection of Pollutant Parameters                135

VII            Control and Treatment Technology                 149
                 Barking                                        149
                 Veneer                                         150
                 Plywood                                        152
                 Hardboard - Dry Process                        156
                 Hardboard - Wet Process                        158
                 Wood Preserving

VIII           Cost, Energy and Non-Water Quality Aspects       233
                 Barking                                        233
                 Veneer and Plywood Manufacturing               234
                 Hardboard - Dry Process                        241
                 Hardboard - Wet Process                        243
                 Wood Preserving - Steam                        253
                 Wood Preserving                                258
                 Wood Preserving - Boultonizing                 258

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IX             The Best Practicable Control Technology          261
               Currently Available
                 Barking                                        261
                 Veneer                                         264
                 Plywood                                        268
                 Hardboard - Dry Process                        270
                 Hardboard - Wet Process                        272
                 Wood Preserving                                274
                 Wood Pregervj-ng - Boultonizing                 275
                 Wood Preserving - Steam                        276

X              The Best Available Technology Economically       281
               Achievable
                 Barking                                        282
                 Veneer                                         283
                 Plywood                                        283
                 Hardboard - Dry Process                        284
                 Hardboard - Wet Process                        284
                 Wood Preserving                                286
                 wood Preserving - Boultonizing                 287
                 Wood Preserving - Steam                        287

XI             Standards of Performance for New Sources         291
                 Barking                                        291
                 Veneer                                         293
                 Plywood                                        293
                 Hardboard - Dry Process                        293
                 Hardboard - Wet Process                        294
                 Wood Preserving                                294
                 Wood Preserving - Boultonizing                 295
                 Wood Preserving - Steam                        295

XII            Acknowledgements                                 299

xiil           References                                       301

XIV            Glossary                                         313
                              VI

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                             FIGURES


Number                             Title                              Pacrg

  1         Wet Barking Process Diagram                     -           13

  2         Simplified Process Flow Diagram for Veneer                 16
              and plywood Production

  3         Detailed Process Flow Diagram for Veneer and Plywood       17

  4         Distribution of Softwood Veneer and Plywood Mills          23
              Throughout the United States

  5         Distribution of Hardwood Veneer and Plywood Mills          24
              Throughout the United States

  6         Distribution of veneer and Plywood Mills in the            32
              State of Oregon

  7         Distribution of Veneer and Plywood Mills in the            33
              State of North Carolina

  8         United states Forest Areas                                 34

  9         Growth of the Plywood Industry in the                      36
              United States

 10         Raw Material Handling in the Hardboard Industry            37

 11         Typical Dry Process Hardboard Mill                         38

 12         Typical Wet Process Hardboard Mill                         47

 13         Geographical Distribution of Hardboard Manufacturing       50
              Facilities in the United States

 14         Process Flow Diagram for a Typical Wood                    53
              Preserving Plant

 15         Water Balance for a Plywood Mill Producing 9.3             73
              Million Square Meters per Year on a
              9.53 Millimeter Basis
                              vi i

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                       FIGURES (Continued)


Number                             Title                              Page

 16         Water Balance for a Typical Dry Process                    92
              Hardboard Mill

 17         Water Usage in Raw Materials Handling                      94
              in the Hardboard Industry

 78         Water Use in the Explosion Process                         96

 19         Effect of Preheating Time and Temperature                  99
              on Yield

 20         The Chemical Components of Wood                           101

 21         Relation Between Dissolved Lignin and wood                103

 22         Process water Recycle in a Typical Wet                    105
              Process Hardboard Mill

 23         Process Water Recycle in a Hardboard Mill Using           107
              the Explosion Process

 24         Water Balance for a Typical wet Process                   112
              Hardboard Mill

 25         variation in Oil Content of Effluent with Time            115
              Before and After Initiating Closed steaming

 26         Variation in COD of Effluent with Time Before             117
              and After Closed Steaming

 27         Variation in COD content and Waste Water                  118
              Flow Rate with Time

 28         Relationship Between BOD and COD for Waste                120
              Waste from a Creosote Treating Operation

 29         source and Volume of Daily Waste Use and Recycling        133
              and Waste Water Source at a Typical Wood-Preserving
              Plant

 30         Plywood Plant Wash Reuse System                           15U
                              vm

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                       FIGURES (Continued)


Number                             Title                              Page

 31         Inplant Treatment and Control Techniques at               160
              No, 7

 32         Typical Wet Process Hardboard Mill with                   162
              Pre-Press

 33         Inplant Treatment and Control Techniques                  163
              at Mill No. 3

 34         Typical Wet Process Hardboard Mill with Savo System       166

 35         Variation of. Effluent BOD and Suspended Solids as         171
              a Function of Time for Mill No. 2

 36         Variation of Effluent BOD and Suspended Solids as a       172
              Function of Time for Mill No. 3

 37         Variation of Effluent BOD and Suspended solids as         173
              a Function of Time for Mill No. 4

 38         Effect of Detention Time on Oil Removal by Gravity        185
              Separation

 39         Determination of Reaction Rate Constant for a Creosote    202
              Waste Water

 40         COD Removal from a Creosote Waste water by Aerated        203
              Lagoon without Sludge

 41         Phenol Content in Weyerhaeuser's Oxidation Pond           212
              Effluent Before and After Installation in
              June, 1966 of Aerator

 42         Relationship Between Weight of Activated Carbon           224
              Added, and Removal of COD and Phenols from a
              Creosote Waste Water

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                       FIGURES (Continued)


Number                             Title                              Page

 43         Waste Water Flow Diagram for Wood Preserving              228
              Plant Employing an Extended Aeration Waste
              Treatment System in Conjunction with Holding
              Lagoons and Soil Irrigation

 44         Waste Water Flow Diagram for wood Preserving              229
              Plant Employing Chemical Flocculation, Sand
              Filtration, and Soil Irrigation

 45         Waste Water Flow Diagram for a wood Preserving            230
              Plant Employing an Oxidation Pond in Conjunction
              with an Aerated Raceway

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                             TABLES


Number                             Title                              Page

  1         Current and Projected Adhesive Consumption in the          21
              Plywood Industry

  2         Summary of Veneer and Plywood Plants in the                25
              United States

  3         Forest Industries 1968 Plywood Statistics                  29

  4         Softwood Plywood Production for 1972                       30

  5         Hardwood Plywood Production in the United States           31

  6         Softwood Plywood Production in the United States           31

  7         Inventory of Hardboard Manufacturing Facilities            48

  8         Consumption of Principal Preservatives and Fire            54
              Retardants of Reporting Plants in the United
              States, 1967-1971

  9         Wood Preserving Plants in the United States by State       56
              and Type

 10         Materials Treated in the United States by product          58
              and Preservatives, 1967-1971

 11         Characteristics of Debarking Effluents                     70

 12         characteristics of Steam Vat Discharges                    72

 13         Characteristics of Hot Water Steam Vat Discharges          74

 14         Analysis of Drier Washwater                                76

 15         Waste Loads from Veneer Driers                             77

 16         Ingredients of Typical Protein, Phenolic and Urea          79
              Glue Mixes

 17         Average chemical Analysis of Plywood Glue                  80

 18         Average Chemical Analysis of Plywood Glue Washwater        81

 19         Characteristics of Glue Washwater                          82

 20         Amount of Adhesive Washwater Generated in southern         83
              Pine Plywood Plants
                              XI

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                       TABLES  (Continued)


Number                             Title                              Page

 21         Glue Waste Discharge Measurements                          84

 22         Dry Process Hardboard - Wastewater Flow and Source         87

 23         Average Chemical Analysis of Plywood Resin                 89

 24         Some Properties of certain United states woods            102

 25         Analyses of Some Common Species of Wood                   104

 26         Waste Water Discharges from wet Process Hardboard         109

 27         Raw Waste Water Characteristics from Wet Process          110
              Hardboard

 28         Progressive Changes in selected Characteristics           117
              of Water Recycled in Closed Steaming Operations

 29         Phenol and COD Values for Effluents from Thirteen         121
              Wood Preserving Plants

 30         Ratio Between COD and BOD for Vapor Drying and            122
              Cresote Effluent Wastewaters

 31         Range of Pollutant Concentrations in Waste Water          122
              from a Plant Treating with CCA- and FCAP-Type
              Preservatives and A Fire Retardant

 32         Raw Waste Loadings for Plant No. 1                        124

 33         Raw Waste Loadings for Plant No. 2                        125

 34         Raw Waste Loadings for Plant No. 3                        126

 35         Raw Waste Loadings for Plant No. 4                        127

 36         Raw Waste Loadings for Plant No. 5                        128

 37         Average Raw waste Loadings for Five Wood-Preserving       129
              Plants

 38         Source and Volume of Water Discharged and Recycled        131
              per Day by a Typical Wood-Preserving Plant

 39         The Adhesive Mixes U^ed  (Cascophen 3566C)                 155

 40         Representative Process Water Filter Efficiencies          165

 41         Primary Settling Tank Efficiency                          167

 42         Treatment Efficiep-y of Biological Systems                        169
                              XII

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                       TABLES (Continued)
Number                             Title                              Page

 43         Example of an ASB System Performance Related              175
              To Temperature

 44         Method of Disposal of Waste Water by Wood                 177
              Preserving Plants in the United States

 U5         Method of Disposal pf Wood Preserving Waste Water         177
              by Region

 46         Compliance with State and Federal Water Standards         178
              Among wood Preserving Plants in the United States

 47         Plans of Wood Preserving Plants not in compliance         178
              with Water Standards in the United States

 48         Type of Secondary Waste Water Treating Facilities         180
              Installed or Planned by Wood Preserving Plants
              in the United States

 49         Type of Secondary Waste Water Treating Facilities         180
              Installed or Planned by Wood Preserving Plants
              by Region

 50         Efficiencies of Oil Separation Process                    184

 51         Effect of Lime Flocculation on COD and Phenol             184
              Content of Treating Plant Effluent

 52         Toxic Constituents in the Principal Salt-Type             189
              Preservatives and Fire Retardant Chemicals
              Used in the United States

 53         Concentrations of Pollutants Before and After             192
              Laboratory Treatment of waste Water from Two Sources

 54         Concentrations of Pollutants in Plant Waste Water         193
              Containing Salt-Type Preservatives and Fire
              Retardants Before and after Field Treatment

 55         BOD, COD and Phenol Loading and Removal Rates             197
              for Pilot Trickling Filter Processing a
              Creosote Waste Water

 56         Relationship Between BOD Loading and Treatability         198
              for Pilot Trickling Filter Processing a Creosote
              Waste Water

 57         sizing of Trickling Filter for a Wood Preserving Plant    199
                              xm

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                       TABLES (Continued)


Number                             Title                              Page

 58         Substrate Removal at Steady-State Conditions in           199
              Activated Sludge Units Containing Creosote
              Waste Water

 59         Reduction in Pentachlorophenol and COD in Haste Water     204
              Treated in Activated Sludge Units

 60         Results of Laboratory Tests of Soil Irrigation Method     205
              of Waste Water Treatment

 61         Reduction of COD and Phenol Content in waste Water        208
              Treated by Soil Irrigation

 62         Average Monthly Phenol and BOD Concentrations in          211
              Effluent from Oxidation Pond at Weyerhaeuser1s
              DeQueen, Arkansas Operation:  1968 and 1970

 63         Effect of Chlorination on the BOD and Phenolic Content    214
              of Pentachlorophenol and Creosote Wastewaters

 64         Effect of Chlorination with Calcium Hypochlorite on the   215
              Pentachlorophenol Content of Waste Water

 65         Effect of Chlorination with Chlorine Gas on the           215
              Pentachlorophenol Content of Waste Water

 66         Effect of Chlorination of Pentachlolophenol Waste         216
              on COD

 67         Chlorine Required to Eliminate Taste in Aqueous           218
              Solutions of Various Phenolic Compounds

 68         Chlorine Demand of M-Cresol After Various Contact         220
              Times

 69         Chlorophenol Concentration in Creosote Waste Water        222
              Treated with Chlorine

 70         Summary of Waste Water Characteristics for 17             231
              Exemplary wood Preserving Plants

 71         Metric Units Conversion Table                             325
                             xiv

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                            SECTION I

                           CONCLUSIONS

For the purpose of establishing effluent  limitations  guidelines
and  standards  of  performance,  the plywood, hardboard and wood
preserving segment of the timber products processing category has
been divided into eight subcategories as follows:    (1)   Barking,
(2)   Veneer,   (3)    Plywood,  (4)   Hardboard-Dry  Process,   (5)
Hardboard-Wet Process, (6) Wood Preserving, (7)  Wood  Preserving-
Steam, and (8) Wood Preserving-Boultonizing.

Readily   apparent  disparities  between  the  type  of  products
manufactured and between the different processes employed in  the
production  of a given product form the primary justification for
the  above  subcategorization.   Distinctions  related   to   raw
material,  plant size and age, and air pollution problems are not
contributary to the subcategorization, as  the  factors  involved
are   minor  non-existent:  quantitative  differences  in  wastes
generated serve to reinforce the subcategorization.

Presently,  20  to  30  percent  of  the   veneer   and   plywood
manufacturing plants are achieving the no discharge limitation as
described   herein.    Many   additional   plants  are  utilizing
manufacturing  practices  and  procedures  that  result   in  ' no
discharge  of  waste water from unit operations within the veneer
and plywood manufacturing  process.   A  small  number  of  mills
utilizing  direct steam conditioning may be unable to meet the no
discharge limitation for  1977, and unwilling or  unable  to  make
the  change to a different method at this time.  The Agency feels
that retention of direct steam conditioning is reasonable for the
present and has thus  promulgated  quantitative  limitations  for
these  particular  operations,  for  the   1977  standards.   1983
standards, however, recognize that technology is  available,  the
application  of  which  would  result  in no discharge of process
waste water.  Twenty-five percent of the  dry  process  hardboard
manufacturers  and  22  percent  of  the  9 wet process hardboard
manufacturers are achieving  the  no  discharge  limitations  set
forth.   Of  the 390 wood preserving manufacturing operations, at
least 5 are currently meeting the no discharge recommendation  in
the  Wood  Preserving-Boultonizing subcategory, and approximately
10 percent of the Wood Preserving-Steam subcategory manufacturers
are achieving the recommended limitations.  It is  believed  that
all  wood  preserving  operations  excluding  those  in  the Wood
Preserving-Steam subcategory can reach the no discharge level  by
July  1, 1977.

It  is  estimated  that  the  capital  costs  of  achieving  such
limitations and standards by all plants within  this  segment  of
the  timber  products  processing industry would be less than $38
million.

These costs would result in an increase in capital investment  by
approximately  $38  million.  As a result, the increased costs of

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the products covered in this segment would range from 1-2 percent
under  present  conditions.   The  above   cost   data   reflects
conditions  where  it  is  assumed  no pollution control measures
exist  within  the  industry.   Because  much  of  the  suggested
technology has already been purchased or is in place, the figures
are higher than the real costs involved.

The  increased  capital  costs  would result in an estimated cost
increase of from 0 to 1 percent  as  compensation  for  pollution
control measures in all but the hardboard subcategory.  Hardboard
prices  could rise as much as 8 percent for industrial board, and
4 to 5 percent for other hardboard products, but the rise  cannot
be  attributed solely or even primarily to the cost of additional
pollution control.

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                           SECTION II
                         RECOMMENDATIONS

The recommended effluent limitations guidelines based upon (1)
best practicable control technology currently available, (2) best
available technology economically achievable, and (3) performance
standards for new sources are summarized below.  The effluent
limitations as set forth herein are developed in depth in the
following sections of this document.

RECOMMENDED EFFLUENT LIMITATIONS BASED ON BEST PRACTICABLE CONTROL
TECHNOLOGY CURRENTLY AVAILABLE
SUBCATEGORY

BARKING
EFFLUENT LIMITATION

A.   No discharge of waste water pollutants
     to navigable waters for barking operations
     excluding those using hydraulic barkers.

B.   For barking operations using hydraulic
     barkers:
VENEER
                        BOD5
                        TSS
               30-Day
               Average
               kg/cu m
               (Ib/cu ft)

               0.5
              (0.03)

               2.3
              (0.144)
 Daily
 Maximum
 kg/cu m
 (Ib/cu ft)

 1.5
(0.09)

 6.9
(0.431)
A.   No discharge of waste water pollutants to
     navigable waters, except for those veneer
     operations using direct steam conditioning

B    For veneer manufacturing operations using
     direct steam conditioning:
                                           BOD
                                  30-Day
                                  Average
                                  kg/cu m
                                  (Ib/cu ft)
                        Softwood  0.24
                        Veneer   (0.015)

                        Hardwood  0.54
                        Veneer   (0.034)
                                    Daily
                                    Maximum
                                    kg/cu m
                                    (Ib/cu ft)

                                    0.72
                                   (0.045)

                                    1.62
                                   (0.10)

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PLYWOOD


HARDBOARD -DRY


HARDBOARD -WET
WOOD PRESERVING
WOOD PRESERVING-
BOULTONIZING
WOOD PRESERVING-
STEAM
No discharge of waste water pollutants to
navigable waters.

No discharge of waste water pollutants to
navigable waters.

BOD5_
TSS
PH
Range
30- Day
Average
kg/kkg
(Ib/ton)
2.6
(5.2)
5.5
(ii.o)
6.0-9.0
Daily
Maximum
kg/kkg
(Ib/ton)
7.8
(15.6)
16.5
(33.0)
6.0-9.0
No discharge of waste water pollutants
to navigable waters
No discharge of waste waters pollutants to
navigable waters.
                        COD
                        Phenols
                        Oil &
                        Grease
               30-Day
               Average
            kg/1000 cu m
            (lb/1000 cu ft)

               550
               (34.5)

                 0.65
                (0.04)
                12.0
                (0.75)

                 6.0-9.0
   Daily
   Maximum
kg/1000 cu m
(lb/1000 cu ft)

   1100
    (68.5)

      2.18
     (0.14)
     24.0
     (1.5)

      6.0-9.0
RECOMMENDED EFFLUENT LIMITATIONS BASED ON BEST AVAILABLE TECHNOLOGY
ECONOMICALLY ACHIEVABLE
SUBCATEGORY

BARKING
EFFLUENT LIMITATION

No discharge of waste water pollutants
to navigable waters.
VENEER
No discharge of waste water pollutants

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                   to navigable waters.
PLYWOOD
HARDBOARD - DRY
HARDBOARD - WET
WOOD PRESERVING
WOOD PRESERVING-
BOULTONIZING
WOOD PRESERVING-
NO discharge of waste water pollutants
to navigable waters.

No discharge of waste water pollutants
to navigable waters.

BOD5_
TSS
pH
Range
30- Day
Average
kg/kkg
(Ib/ton)
0.9
(1.8)
1.1
(2.2)
6.0-9.0
Daily
Maximum
kg/kkg
(Ib/ton)
2.7
(5.4)
3.3
(6.6)
6.0-9.0
No discharge of waste water pollutants
to navigable waters.

No discharge of waste water pollutants
to navigable waters.
                        COD


                        Phenols
                        Oil&
                        Grease

                        pH
                       Range
               30-Day
               Average
              kg/1000 cu m
               (lb/1000 cu ft)

               110
                (6.9)

                 0.064
                (0.004)

                 3.4
                (0.21)

                 6.0-9.0
 Daily
 Maximum
kg/1000 cu m
 (lb/1000 cu ft)

 220
 (13.7)

   0.21
  (0.014)

   €.9
  (0;42)

   6.0-9.0
RECOMMENDED EFFLUENT LIMITATIONS AND NEW SOURCE PERFORMANCE STANDARDS

SUBCATEGORY        EFFLUENT LIMITATION
BARKING
A.   No discharge of waste water pollutants to
     navigable waters for barking operations,
     excluding those which use hydraulic barkers.
                   B.   For new sources using hydraulic barkers:

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VENEER


PLYWOOD


HARDBOARD


HARDBOARD
DRY


WET
WOOD PRESERVING
WOOD PRESERVING-
BOULTONIZING
                        BODS
                        TSS
                      30-Day
                      Daily
                      kg/cu m
                      (Ib/cu ft)

                      0.5
                     (0.03)

                      2.3
                     (0.144)
                                    Daily
                                    Maximum
                                    kg/cu m
                                    (Ib/cu ft)

                                    1.5
                                   (0.09)

                                    6.9
                                   (0.431)
       No discharge of waste water pollutants to
       navigable waters.
No discharge of waste water
navigable waters.

No discharge of waste water
navigable waters.

               30-day
               Average
               kg/kkg
               (Ib/ton)
pollutants to


pollutants to
                        BODS
                        TSS
                        PH
                        Range
                        0.9
                       (1.8)

                        1.1
                       (2.2)

                        6.0-9.0
        Daily
        Maximum
        kg/kkg
        (Ib/ton)

          2.7
         (5.4)

          3.3
         (6.6)

          6.0-9.0
       No discharge of waste water
       navigable waters.

       No discharge of waste water
       navigable waters.
                            pollutants to


                            pollutants to
WOOD PRESERVING-
STEAM
                      30-Day
                      Average
                    kg/1000 cu m
                      (lb/1000 cu ft)

            COD         110
                         (6.9)

            Phenols       0.064
                         (0.004)
                                    Maximum
                                    Daily Average
                                    kg/1000 cu m
                                    (lb/1000 cu ft)

                                      220
                                      (13.7)

                                        0.21
                                       (0.014)

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Oil &         3.4     6.9
Grease        (0.21)     (0.42)

pH       6.0-9.0      6.0-9.0
Range

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                           SECTION III

                          INTRODUCTION

PURPOSE AND AUTHORITY

Section  301(b)   of  the  Federal  Water  Pollution  Control  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
applicat ion  of  the  be st  ava ilable   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 per-
mitting 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,
operati on   method s  and  other  alternatives.   Th e  regulati ons
proposed  herein  set  forth  effluent   limitations   guidelines
pursuant  to  Section  304(b) of the Act for selected segments of
the timber products processing category.

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  regu-
lations  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 -Administrators intent to establish, under
Section 306, standards of performance applicable to  new  sources
within the timber products processing category.

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Similar  studies  will  be undertaken and published by the EPA in
future  months.   Segments  of  the  timber  products  processing
industry  to  be  covered  at  that  time  will include machining
operations, storage  of  fractionalized  wood,  insulation  board
manufacture,   particle  board  manufacture,  storage  operations
(including  log  ponding  and  wet-decking) ,  logging  camps  and
contractors,   saw   and   planing   mills,   prefabricated  wood
structures, special purpose sawmills, millwork,  and  other  wood
products not elsewhere classified.

BASIS FOR GUIDELINES DEVELOPMENT
The  effluent limitations guidelines and standards of performance
recommended in  this  report  were  developed  in  the  following
manner.

Both  detailed  and  general  information  was  obtained  on  the
manufacturing plants identified as currently in  operation.   The
sources and type of information consisted of:

         Applications of the Corps of Engineers  for  Permits  to
         Discharge  under  the  Refuse Act Permit Program  (RAPP),
         obtained for exemplary plants.   The  RAPP  applications
         provided  data  on  the  characteristics  of  intake and
         effluent waters, water usage, waste water treatment  and
         control  practices  employed,  daily production, and raw
         materials used.

         Internal reports furnished by the industry  and  various
         manufacturers.    The   information  included:   (a)  raw
         materials utilized and relative amounts,   (b)  schematic
         diagrams  of  inplant  processes  (with  a definition of
         process type) showing waste water discharge and  recycle
         systems, (c) production rates,  (d) definition of sources
         of  waste  water  from inplant processes, including flow
         and waste water chemical composition,  (e) definition  of
         total  waste  water  flows and chemical composition,  (f)
         present methods of waste water  handling  or  treatment,
         including schematic diagrams of treatment systems with a
         definition  of  chemical  composition  after  each  unit
         process of the treatment  systems,   (g)  description  of
         solid  wastes  resulting  from treatment systems and the
         methods of handling and  disposal  of  the  wastes,   (h)
         energy  requirements  per unit of production  (i) inplant
         methods of waste  water  reduction  or  control   (reuse,
         conservation,  etc.)  and,   (j)  effects  of waste water
         handling on air pollution and solid waste disposal.
         On-site  visits  and  interviews  at
         processing plants throughout the U.S.
timber   products
                              10

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    -    Other sources of information,  including  EPA  technical
         reports   and   personnel,  trade  literature,  industry
         personnel, and special consultants.  References used  in
         this study are tabulated in Section XIII*

This  information  was compiled by data processing techniques and
analyzed for the following:

         Identification of  distinguishing  features  that  could
         potentially  provide  a  basis  for subcategorization of
         these  selected  portions   of   the   timber   products
         processing category.

    -    Determination of the waste water usage and  waste  water
         characteristics  for  each  subcategory, as developed in
         Section IV and discussed in Section V, including (1) the
         source and  volume  of  water  used  in  the  particular
         process  employed  and  the  source  of wastes and waste
         waters in the plant, and  (2) the constituents (including
         thermal) of all waste waters, including pollutants,  and
         other  constituents  which  result  in  taste, odor, and
         color in water or aquatic organisms.

         Identification  of  those  constituents   discussed   in
         Section V and Section VI which are characteristic of the
         industry  and  present  in  measurable  quantities, thus
         being  pollutants  subject   to   effluent   limitations
         guidelines and standards.

         The full range of  control  and  treatment  technologies
         existing  within  each  subcategory,  including an iden-
         tification  of  each  distinct  control  and   treatment
         technology  existent  or  capable  of being designed for
         each subcategory, 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  re-
         quired implementation time.

         The non-water quality environmental impact, such as  the
         effects  of  the  application  of such technologies upon
         other pollution problems, including  air,  solid  waste,
         noise and radiation

         The energy requirements  of  each  of  the  control  and
         treatment  technologies,  as  well  as  the  cost of the
         application of such technologies.


The information outlined above was then  evaluated  in  order  to
determine   what  levels  of  technology  constituted  the   "best
                              11

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practicable  control  technology  currently   available,"   "best
available  technology  economically  achievable,"  and  the "best
available demonstrated control technology,  processes,  operation
methods    or   other   alternatives."    In   identifying   such
technologies, various  factors  were  considered,  including  the
total  cost  of  application  of  technology  in  relation to the
effluent reduction benefits to be achieved from such application,
the  age  of  equipment  and  facilities  involved,  the  process
employed,  the  engineering aspects of the application of various
types of  control  techniques   (including  energy  requirements),
process changes, non-water quality environmental impact and other
factors.   Consideration  of  the technologies was not limited to
those presently employed in the industry, but included also those
processes in pilot plant or laboratory research stage  and  those
used   by   other   industries.    The  alternative  of  combined
industrial-municipal treatment, including the  compatibility  and
economic ramifications, was also examined.
GENERAL DESCRIPTION OF THE INDUSTRY SEGMENT

The timber products processing category includes a broad spectrum
of  operations  ranging from cutting and removing the timber from
the forest to the processing of the timber into a wide variety of
finished products, encompassing such diverse  items  as  finished
lumber,   and   cooked,   molded,   or   compressed  wood  fibers
reconstituted into a number of  sheet  form  flexible  and  rigid
products.   The  wide variety of processing steps and products in
the timber products processing industry are, in  many  instances,
similar only in the fact that the basic raw material is wood.

This  development  document  addresses  the segment of the timber
products processing industry  which  has  been  estimated  to  be
responsible for the greatest water pollution problems.  The first
segment  of  the study of the timber products processing industry
includes barking, veneer  manufacturing,  plywood  manufacturing,
hardboard manufacturing, and wood preserving operations.

BARKING

Barking  may  be  the  common starting point throughout the  (post
harvest,  transport  and  delivery)  timber  products  processing
industry.   If  barking  is  required, logs are taken to a barker
where the bark is removed through  one  of  several  wet  or  dry
barking  procedures.   The  logs  may  be cut to required lengths
before or after barking  (figure 1).

Types of barking machines include   (1)  drum  barkers,   (2)  ring
barkers,    (3)  bag  barkers,   (4)  hydraulic  barkers  and,   (5)
cutterhead barkers.

Drum barkers range in size from 2.4 to 4.9 m   (8  to  16  ft)  in
diameter  and  up  to  22.8  m   (75 ft) in length.  A drum barker
consists  primarily  of  a  cylindrical  shell  rotating  on  its
                              12

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    r
•-

LOG
STORAGE

^
PROCESS
WATER

r *
PROCESS
BACK WATER
1
t
LOG
WASHER

T
i *
-.
WET DRUM
POCKET OR
HYDRAULIC BARKER
                                          DEBARKED
                                          LOGS
                                          OFF GASES
                                          CYCLONE
COARSE
SCREENING
*-^-
FtNE
SCREENING
4--*
^ *<***
4_
-f-
i
BARK PRESS
                     r*"1!. •
                        •*4-4»*4H
                   ASH TO LAND
                   DISPOSAL
                                         k-*-'
DIVERSION
BOX
    I

    i
EFFLUENT
                   PRODUCT AND
                   RAW MATERIAL

                   PROCESS WATER

                   BACK WATER
                   GASES

                   BARK ASH
                   RESIDUE

                   EFFLUENT
                                           4-^44--
+

t

*
                                      i

                                      f

                                     .J-
   FIGURE .1
       - WET BARKING PROCESS DIAGRAM

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longitudinal  axis.   Logs are fed into one  end and tumbling and
rolling action removes the bark.  Water sprays  may  be  used  to
reduce  dust,  promote  the  thawing of wood in cold climates, or
reduce the bond between the bark and wood.

Ring barkers or rotary barkers consist  of  a  rotating  ring  on
which several radial arms are pivoted.  On the end of each arm is
a  tool  which  abrades  or  scrapes off the bark.  A ring barker
handles only one log at a time, but can handle logs up  to  213.4
cm (84 in) in diameter.

Bag barkers or pocket barkers are simple stationary containers in
which the logs are rotated to remove bark by abrasion.  Water may
also  be used in this process for the same purposes described for
the drum barkers.

Cutterhead barkers  remove  bark  by  the  milling  action  of  a
cylindrical  cutterhead as it rotates parallel to the axis of the
logs which are fed through the unit.  No  water  is  employed  in
this operation.

The hydraulic barker uses a high pressure water jet to blast bark
from  a  log.  Pressures from 55.4 to 109.9 atm (800 to 1615 psi)
are used with flow in the range of 25.2 to 101 I/sec  (400 to 1600
gal/min).  Because of the large volumes  of  low  solids  content
water required for this operation, there is an apparent inability
to  recycle  water  from  this  operation,  which  results  in  a
relatively large volume waste water discharge.  Hydraulic barkers
are slowly being phased out because  of  water  requirements  and
because  the  large  diameter  logs  they  process  are  becoming
unavailable.
VENEER AND PLYWOOD

Plywood is an assembly of layers of wood  (veneer) joined together
by  means  of  an  adhesive.   It   is   a   multi-use   material
characterized  by  its  ability to be designed and engineered for
construction and decorative purposes, flat  shapes,  curves,  and
bent  shapes.   Hardwood  plywood  is distinguished from softwood
plywood in that the former is generally used for decorative  pur-
poses  and  has  a  face ply of wood from deciduous or broad leaf
trees.  Softwood plywood is generally used for  construction  and
structural  purposes, and the veneers are of wood from coniferous
or needle bearing trees.

Raw Materials

A great assortment of woods are utilized in  the  manufacture  of
veneers.    A   high   percentage   of  veneer  produced  in  the
northwestern U.S. is manufactured from Douglas fir,  with  lesser
quantities  of  veneer  made from ponderosa pine and hemlock*  In
the  southeast  U.S.,  southern  pine  is  the  predominant   raw
                              14

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material.    Veneer   is  classified  as  softwood  or  hardwood.
Softwood veneer is manufactured on the west coast, in  the  Rocky
Mountain  region, and in the southeastern U.S..  The species that
are used in the western U.S. include Douglas fir,  sitfca  spruce,
western hemlock, balsam fir, western larch, ponderosa pine, sugar
pine,  western  white  pine,  and  redwood.   In the southeastern
states bald cypress and  southern  pine  are  most  common.   The
hardwood  species  commonly  used  in  the U.S. are beech, birch,
maple, basswood, red  gum,  yellow  poplar,  cottonwood,  tupelo,
sycamore,  oak,  walnut,  lavan,  elm,  cherry,  hickory,  pecan,
cativo, teak, rosewood, and mahogany.

Softwood veneer is almost exclusively used in  the  manufacturing
of  softwood  plywood.  Small quantities are used as center stock
and cross-banding for panels made with hardwood faces.   Hardwood
veneer uses can be categorized as  (1) face veneer,  (2) commercial
veneers, and  (3) veneers for containers.  Face veneers are of the
highest  quality  and are used to make plywood panels employed in
the manufacture of  furniture  and  interior  decorative  panels.
There  are more than 50 such manufacturers throughout the eastern
U.S..  Commercial veneers are those used for cross bands,  cores,
and  backs  of  plywood  panels and concealed parts of furniture.
Container veneers consist  of  a  large  variety  of  inexpensive
veneers  used  in the manufacturing of crates, hampers, fruit and
vegetable baskets and kits, boxes and similar container items.


Plywood is manufactured in 36 states.  The majority  of  softwood
plywood  is   produced  on the Pacific Coast while the majority of
the hardwood  plywood is manufactured in the southeastern  states.
The  hardwood  plywood  industry  is made up of a large number of
small factories distributed widely over the eastern U.S..

Manufacturing Process
The various operations for converting roundwood into  veneer  and
finally  into  plywood  are  chiefly  mechanical.   A  simplified
process flow diagram for the production  of  veneer  and  plywood
from  roundwood  is shown in Figure 2.  A detailed flow diagram o
the veneer and plywood manufacturing process is shown  in  Figure
3.

The  most  important  operation in this process is the cutting of
the veneer; the appearance of a  plywood  panel  is  greatly  de-
pendent upon the manner in which the veneer is cut.  Prior to the
cutting  of  veneer,  logs  may be heated, or "conditioned"; this
serves to improve the cutting properties  of  wood,  particularly
hardwood.   Historically,  both  hardwood and softwood mills have
practiced log conditioning.  There was in recent  years  a  trend
away  from  log  conditioning  in  the softwood industry, but the
current trend is again toward this practice.
                              15

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LOG
STORAGE


DEBARKER
-


LOG
CONDITIONER


                             i
VENEER
CUTTER


VENEER
DRIER
          VENEER  OPERATION
VENEER
PREPARATK>


GLUE
LINE


PRE$S



FINISHING
         PLYWOOD  OPE RAT ION
FIGURE 2 -  SIMPLIFIED PROCESS FLOW DIAGRAM FOR
           VENEER AND PLYWOOD PRODUCTION
             16

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LIQUID  WASTE
                 GREEN END
     OVERFLOW FROM
     LOG POND
LOG STORAGE
{LOG POND,
COLD DECK
OR BOTH)
GASES
LIQUIDS
                                                  DRIER WASH
                                       CONDENSATE  AND DELUGE
                                                  WATER
EXHAUST
GASES
                       BARK
SOLID WASTE IS BURNED IN BOILER
CHIPPED  FOR  REUSE OR SOLD
                                                               GLUE
                                                               PREPARATION
                                                                                 GLUE WASH
                                                                                 WATER
                                                      VENEER
                                                    PREPARATION
UE
|

GLUE
LINE


RECYCLf
1 RESSIN(

                                                                                     FINISHING
                                                           | UNUSABLE
                                                           I VENEER AND
                                                           ! TRIMMINGS
                                                           I
                                                           I

                                                          i.
                                                                                         TRIM AND
                                                                                         SANDER
                                                                                         DUST
           FIGURE  3 - DETAILED PROCESS FLOW DIAGRAM  FOR VENEER AND PLYWOOD

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When conditioning of logs occurs not only prior to veneering, but
prior to debarking, it facilitates the barking operation.    This
has  been a common practice in the past.  With the increasing use
of ring and cutterhead barkers whose operations are not aided  by
prior  heating,  heating  commonly occurs between the barking and
veneering operations.

There are basically two methods of heating logs:   (1)  by  direct-
ing  steam  onto the logs in a "steam vat" (steam tunnel), and by
(2) heating the logs in a "hot water vat" full of water which  is
heated  either  directly with live steam or indirectly with steam
coils.

Heating in steam vats is generally more violent than in hot water
vats, and steam vats are therefore more applicable to species  of
wood  that  do  not  rupture  under  rapid and sudden thermal in-
creases.   The  times  and  temperatures  of  these  conditioning
processes  vary  with species, age, size, and character of veneer
to be cut.  The experience has been that the harder (more  dense)
the  species  and  the  more  difficult  to  cut,  the longer the
conditioning period and the lower the temperature required.  Some
of the softer woods, such as poplar, bass wood,  cottonwood,  and
certain   conifers,   can  be  cut  satisfactorily  without  such
conditioning.

Veneer Cutting

The principal unit process in the manufacturing of veneers is the
cutting of the veneer.   There  are  four  methods  used  to  cut
veneer:   (1)  rotary cutting, (2) slicing, (3) stay log cutting,
and  (4) sawn veneering.

Currently more than 90 percent of all veneer is rotary  cut.   In
this  method  of  cutting,  a  log  or "bolt" of wood is centered
between two chucks on a lathe.  The  bolt  is  turned  against  a
knife  extending across the length of the lathe, and a thin sheet
of veneer is peeled from the log as it turns.  Lathes capable  of
peeling  logs from 3.66 to 4.88 m  (12 to 16 ft) in length are not
uncommon, but more often veneer is cut in  lengths  ranging  from
0.61 to 2.4 m  (2 to 8 ft).  The bolts that are to be veneered are
usually cut from 10 to 15 cm  (4 to 6 in) longer than the width of
veneer to be cut from them.

Most slicers consist of a stationary knife.  The section of a log
or "flitch" to be cut is attached to a log bed which moves up and
down, and on each downward stroke a slice of veneer is cut by the
knife.   Slicers  are  used primarily for cutting decorative face
veneers from woods such as walnut, mahogany, cherry, and oak.

Stay log cutting produces veneers which are intermediate  between
rotary  cut  and  sliced veneers.  A flitch is attached to a stay
log or metal beam, mounted off center to  a  rotary  lathe.   The
stay  log  method  produces  half-round veneer which is generally
used for faces.
                              18

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A small quantity of veneer is cut by sawn veneering.  A  circular
type  saw  with  a  thin,  segmented blade, called a segment saw,
turns on an arbor.  The thin blade reduces  the  wastage  or  saw
kerf.   This  method  generally  is used only for certain species
such as oak, red cedar and Spanish  cedar  in  order  to  achieve
special effects.

Veneers  are  cut  to  thicknesses  ranging from 0.254 to 9.54 mm
(1/10 to 3/8 in).  Most of the rotary cut veneers are either 3.6,
3.2, 2.5, 1.7, or 1.3 mm  (1/7, 1/8, 1/10,  1/  15,  or  1/20  in)
thick.   Sliced veneer usually ranges from 1.27 to 0.635 mm (1/20
to 1/40 in).  Sawn veneers vary from 6.35 to  0.795  mm   (1/4  to
1/32 in) in thickness.

After  rotary  veneers are cut, they may go directly to a clipper
or they may be stored temporarily on  horizontal storage decks or
on reels.  Usually the veneer coming from the  lathe  is  cut  to
rough  green  size, and defects are removed at the green clipper.
From here the veneers are conveyed to the dryers.

Veneer Drying

Freshly cut veneers are ordinarily unsuited for gluing because of
their wetness.  In the undried  (green) state,  veneers  are  also
susceptible  to  attack by molds, blue-stain, and wood-destroying
fungi.  It is therefore necessary to remove the  excess  moisture
rapidly,  and  veneers are usually dried to a moisture content of
less than 10 percent.  This is a level  compatible  with  gluing,
and  consistent  with  the  moisture  content  to  which  plywood
products will be exposed while in service.

Several methods for drying veneers are in use.  The  most  common
type  of  dryer  is a long chamber equipped with rollers on belts
which advance the  veneer  longitudinally  through  the  chamber.
Fans and heating coils are located on the sides of the chamber to
control temperature and humidity.

The  majority  of  high-temperature  (above 100°C or 212°F) veneer
dryers depend upon steam as a heat source.  The  heat  is  trans-
ferred  to the air by heat exchangers.  However, direct-fired oil
and gas dryers are becoming increasingly common in the industry.

The conventional progressive type  and  compartment  type  lumber
kilns  are  also used in drying veneers.  Air drying is practiced
but is quite rare except in the production of  low  grade  veneer
such  as  that  used  in  crate  manufacturing.   Air  drying  is
accomplished by simply placing the veneer in stacks open  to  the
atmosphere,  but  in  such  a way as to allow good circulation of
air.

Veneer Preparation

Between the drying and gluing operations are a  series  of  minor
operations that prepare or repair the veneer stock.  These opera-
                              19

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tions  may  include grading and matching, redrying, dry-clipping,
jointing, taping and splicing, and inspecting.  These  operations
are  self-descriptive  and completely mechanical or manual except
for jointing and splicing which may use some  sort  of  adhesive.
The  bonding  does not have to be as strong as that in the gluing
of plywood, and the amount of adhesive used is kept to a minimum.
Most of these gluing operations do not require washing.

Gluing Operations

A number of adhesives can be used in the manufacture of  plywood.
For  the  purpose of this discussion, distinction is made between
(1)  protein, (2)  phenol-formaldehyde, and  (3)  urea-formaldehyde
glues, since these are the classes of glue most often used in the
industry.   Protein glue is extracted from plants and animals and
is  thermoplastic,   while   the   other   two   are   synthetic,
thermosetting  glues.   Typical  ingredients of protein glues are
water, dried blood, soya flour, lime,  sodium  silicate,  caustic
soda   and   a   formaldehyde   doner  for  thickening.   Typical
ingredients  of  urea-formaldehyde  glues  are  water,  defoamer,
extender   (wheat  flour)  and  urea  formaldehyde resin.  Typical
ingredients of  phenol-formaldehyde  glues  are  water,  furafil,
wheat  flour,  phenolic formaldehyde resin, caustic soda and soda
ash.

Both protein and urea-formaldehyde  glues  are  chiefly  interior
glues,  while  phenol-formaldehyde  is  an  exterior glue.  Urea-
formaldehyde is used almost exclusively in the  hardwood  plywood
industry  when  the  panels  are  used  for  furniture and indoor
panelling.  Phenol-formaldehyde is  a  thermosetting  resin  like
urea-formaldehyde,  but  it  is waterproof and is practically the
only glue used to make exterior plywood.  Phenol-formaldehyde, is
being increasingly used to produce  both  interior  and  exterior
plywood  so  that  the  use  of  phenolformaldehyde is increasing
rapidly.  Table 1 shows the breakdown of glue usage in  1965  and
the  projected  usage  for  1975.   At  present,  phenolic  glues
comprise about 50 percent of all glue consumed while by  1975  it
is  projected  that  about  80  percent  of  all the glue used in
plywood manufacturing will be phenolic based.

Historically, protein glues had been the only  adhesive  used  in
the  plywood  industry.  However, as a result of synthetic resins
becoming less  expensive  and  their  versatility  becoming  more
recognized,  the  use  of  protein glues is disappearing.  At the
present time, the main advantage of some protein  glues  is  that
they  can  be  cold  pressed.   However, while cold pressing is  a
simpler and  cheaper  operation,  it  is  only  satisfactory  for
interior plywood.

Most plywood manufacturers mix their own glue in large dough-type
mixers.   The  glue  is  then applied to the veneer by means of  a
spreader, the most common of which consists of two  power  driven
rollers  supplied  with  the adhesive.  Protein glues are usually
applied with steel rollers, while other glues are usually applied
                              20

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                            TABLE 1

       CURRENT AND  PROJECTED ADHESIVE CONSUMPTION  IN

                    THE PLYWOOD INDUSTRY


                  		 (Millions of Kilograms)
              	1965	1975	
Plywood Type  Phenolic  Urea  Protein   Phenolic   Urea  Protein

Western
Exterior          37       —      —         88

Western
Interior         6.4       —      47         62

Southern
Exterior          —       •*-      —         41       —

Southern
Interior         4.5       —      —         39

Hardwood          —       25      —         —       54
TOTALS            48      25      47        230       54
                               21

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with rubber-covered  rollers.   More  recently  the  practice  of
applying glue by means of sprays and curtain coaters has emerged.
Since all glues harden with time, the glue system must be cleaned
regularly  to  avoid  build-up  of  dried glue.  Some of the more
recent spray curtain-coater glue applicators require less washing
than the conventional rollers.

Pressing

After gluing, the layers of veneer are subjected to  pressure  to
insure  proper alignment and an intimate contact between the wood
layers and the glue.  The adhesive is allowed to  partially  cure
under pressure.  Pressing may be accomplished at room temperature
(cold-pressing)  or  at  high  temperature (hot-pressing).  Cold-
pressing  is  used  with  some  protein   and   urea-formaldehyde
adhesives.   Hot-pressing equipment is used to cure some protein,
some urea-formaldehyde, and all of  the  phenol-formaldehyde  ad-
hesives.

Most presses are hydraulic and apply pressures from 6.1 to 17 atm
(75 to 250 psi) .  Cold presses are operated at room temperatures,
while  hot  presses are operated at temperatures ranging to 177°C
(350°F) with heat being transferred by means of steam, hot  water
or  hot oil.  Plywood pressing time ranges from two minutes to 24
hours depending upon the temperature of the press and the type of
glue used.  Usually,  the  hotter  the  press,  the  shorter  the
pressing time.

In  recent  years,  radio-frequency  heat  has  been used to cure
synthetic resin adhesives.  This works on the principle that when
an  alternating  electric  current  oscillating  in   the   radio
frequency range is applied to a dielectric material, the material
will  be  heated.   It  is  questionable  whether  this method of
heating is economically worthwhile, however.  It  is  technically
applicable  for  curing  the  resin  in  plywood  as well as edge
gluing.

Finishing

After the pressing operation, any number of a series of finishing
steps, depending upon the operation and the product desired,  may
be  taken.   These operations include  (1) redrying,  (2) trimming,
(3) sanding,  (4) sorting,  (5) molding and  (6) storing.

Inventory of Veneer and Plywood Manufacturers
There are approximately  500 veneer  and plywood mills  in the  U.S.,
248  of which  use   softwood,   253  use  hardwood,  and 27  use   a
combination   of   softwood  and hardwood.  As  shown in  Table 2, the
largest concentrations of  mills are in  Oregon,  Washington,  and
North  Carolina.   Figures 2 through 5 show the distribution  of
mills throughout  the  U.S..   Hardwood  and  softwood mills are
located  according to   availability of raw materials, and  their
                               22

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ro
CO
                                                    SOFTWOOD - PLYWOOD
                                                        8  VENEER
                                              O   SOFTWOOD a  HARDWOOD-
                                                   PLYWOOD  3  VENEER
                      NOTE:
                          OREGON AND WORTH CAROL! NA ABE KI9H
                          DENSITY AREAS AND ARE SHOWN ON SEPARATE
                          MAPS
                                        FIGURE 4  - DISTRIBUTION OF SOFTWOOD VENEER AND PLYWOOD  MILLS  THROUGHOUT THE UNITED STATES

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                                    HARDWOOD - PLYWOOD

                                         »  VENEER
                                    SOFTWOOD a HARDWOOD

                                    PLYWOOD a  VCNEER
NOTE :
    OREGON AND NORTH CAROLINA ARE HIQH DENSITY
    AREAS AND ARE SHOWN ON SEPARATE MAPS.
                                                                                                                            Miami
                       FIGURE 5 - DISTRIBUTION OF  HARDWOOD VENEER AND PLYWOOD HILLS THROUGHOUT THE UNITED STATES

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                         TABLE  2




SUMMARY OF VENEER AND  PLYWOOD  PLANTS IN THE UNITED STATES
     SOFTWOOD PLYWOOD




   Alabama            6




   Arizona            1




   Arkansas           8




   California        15




   Colorado           1




   Florida            2




   Georgia            5




   Idaho              5




   Louisiana         12




   Maryland           1




   Michigan           2




   Mississippi        6




   Montana            4




   New Hampshire      1




   North Carolina     6




   Oklahoma           1




   Oregon            81




   South Carolina     3




   Texas              9




   Virginia           1




   Washington        29




   TOTAL            199
  SOFTWOOD VENEER




Arkansas         1




California       8




Florida          1




Georgia          1




Maryland         1




Minnesota        1




New Jersey       1




North Carolina   6




Oregon           31




South Carolina   1




Texas            1




Virginia         1




Washington       9




Wisconsin     	2




TOTAL            65
                                     25

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                 TABLE 2  CONTINUED
 HARDWOOD PLYWOOD
HARDWOOD VENEER
Alabama
Arkansas
California
Florida
Georgia
I llinois
Indiana
Louisiana
Maine
Michigan
Minnesota
Miss issippi
9
4
6
3
6
1
6
2
3
4
2
6
Alabama
Florida
Georgia
Illinois
Indiana
Iowa
Kentucky
Maine
Maryland
Michigan
Minnes ota
Miss issippi
4
4
5
1
13
2
4
1
1
3
2
3
New Hampshire       2




New York            2




North Carolina     26




Oregon              9




Pennsylvania        4




South Carolina     16




Tennessee           4




Texas               3




Vermont             5




Virginia           11




Washington          5




West Virginia       1




Wisconsin          16





TOTAL            157
Missouri          2




New Jersey        1




New York          5




North  Carolina   19




Ohio              2




Oregon            5




Pennsylvania      5




South  Carolina    6




Tennessee         2




Vermont           1




Virginia          7




West Virginia     2




Wisconsin         4
                                   TOTAL
                107
                                 26

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                                             TABLE  2  CONTINUED
                      SOFTWOOD & HARDWOOD  PLYWOOD
                         Alabama              2
                         Florida              1
                         Michigan             1
                         New  Hampshire       1
                         North Carolina      1
                         Oregon               3
                         South Carolina      1
                         Texas                1
                         Washington       	4
                         TOTAL               16
SOFTWOOD &  HARDWOOD VENEER
     Florida            1
     Georgia            1
     Minnesota          1
     North  Carolina    3
     Oregon              3
     Virginia           1
     TOTAL              11
Region
New
England

Middle
Atlantic

East North
Central

West North
Central

South
Atlantic

East South
Central

West South
Central

Mountain

Paci fi c
                                          TOTAL PLYWOOD  PLANTS  - 340
                                          TOTAL VENEER PLANTS   - 161
Total
                                                              27

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di stributi on, t
in Figure 7.  A
presented in Ta

In  1968,  a Fo
statistics avai
there were 175
hardwood   plyw
installations w
plywood  in  th
basis (15 billi
hardwood  plywo
0.635 cm basis
Table  3  are  :
collected  as  ;
association  sh*
1.71 billion sq
3/8  in  basis) ,
million sq m on
basis).

During  the  de<
rose by 150 per<
the world's plyv
the  U.S.  alone
timber.  As the
increase  so  d<
ago practically
produced  in th<
ten years the ir
and  the  use oj
Nation's softwoc
Hardwood plywooc
past 20 years  (1

HARDBOARD

Hardboard is a g
from  interfelte
and pressure in
ft) or greater.
properties,  sue
resistance to ab
strength, durabi
There  are two m
the manner in wh
water  is  used
distributing the
function  in the
developed from a
o
e?
LU
(=»
O
o
3

Q_
(=>
O

C3
                                                     32

-------
EGEND







 SOFTWOOD




 HARDWOOD



 SOFT AND HARDWOOD
                          FIGURE 6 - DISTRIBUTION OF VENEER AND PLYWOOD HILLS IN THE STATE OF OREGON

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                    TABLE 5



HARDWOOD PLYWOOD PRODUCTION IN THE UNITED STATES





Year                  Square Meters Surface Area



1947                         68,700,000



1955                         87,000,000



1960                         82,500,000



1965                        170,500,000



1970                        146,600,000



1972                        204,765,000
                    TABLE 6



SOFTWOOD PLYWOOD PRODUCTION IN THE UNITED STATES
Year
1925
1940
1950
1960
1970
1972
Sq. Meters Surface Areas
14,240,000
111,690,000
237,700,000
727,500,000
1,334,700,000
1,707,400,000
No. of Plants
12
25
68
152
179
—
                       31

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               TABLE 4
SOFTWOOD PLYWOOD PRODUCTION FOR 1972

  State     Sq. Meters-9.53 mm Basis
California         140,543,000
Oregon
Washington
Idaho
Others
(Mostly South)
803,700,000
210,443,000
156,366,000
495,066,000
   Note:  Data obtained from APA
                   30

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              TABLE 3
FOREST INDUSTRIES 1968 PLYWOOD STATISTICS
Region
New
Engl and
Middle
Atlantic
East North
Central
West North
Central
South
Atlantic
East South
Central
West South
Central
Mountain
Pacific
Total
Number of
Softwood
Plywood
Plants
-
-
-
-
10
7
.17
11
130
175
Softwood Ply-
'. wood Production
In Square meters
(9.53 rtm Basis)
-
-
-
-
54,730,000
49,500,000
142,500,000
101,720,000
1,063,000,000
1,411,500,000
Number of
Hardwood
Plywood
Plants
- 15
7
41
4
72
24
11

31
205
Hardwood Ply-
wood Production
In Square meters
(6.35 mm - Basis)
7,175,000
1,675,000
29,950,000
4,200,000
42,660,000
30,625,000
4,100,000
-
77,375,000
197,750,000
                  29

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CO
CO
                                 •   SOFTWOOD

                                 A -  HARDWOOD

                                 •   SOFT AND HARDWOOD
                                                                                                               WILMINGTON
                                         FIGURE 7-  DISTRIBUTION OF VENEER AND PLYWOOD hILLS IN THE STATE OF NORTH CAROLINA

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                                                   UNITED STATES FOREST AREAS
CO
                      Softwood timber is indicated by grey
                      hardwood by black areas.
                                         FIGURE 8
- UNITED  STATES  FOREST AREAS

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Mason  during  the  1920's.   It was the prototype of wet process
hardboard.   Other  methods  of  fiber  preparation  were   later
developed.   The  resulting  fibers  may be washed, screened, and
refined before being carried in  a  liquid  slurry  to  a  board-
forming   machine  similar  to  that  used  in  making  paper,  a
cylindrical former, or a batch unit.  After forming, the wet  mat
may  be  pressed  either wet or dry.  If the mat is to be pressed
dry, then all of the moisture  must  be  removed  by  evaporation
after wet-forming.

Fiber  preparation  in  the dry process is similar to that in the
wet process.  After fiber preparation,  water  is  removed  in  a
dryer.   The  fibers  are  then transported by an air stream to a
dry-felting machine for mat formation.  After  formation  of  the
dry  mat, the mat is pressed in a dry state by all but two of the
dry press hardboard mills to" be discussed later.  Two  mills  add
water  to  the  mat after dry formation and in one mill any water
added is evaporated in the pressing operation.

Process Description

The raw material for  hardboard  production  is  essentially  all
wood.   This  wood  may  be in the form of round wood, wood chips
from waste products from saw mills and plywood  mills,  or  other
sources  of  wood  fiber.  Raw material handling for both wet and
dry process hardboard mills is shown in Figure 9.

Figure 10 shows a  typical  process  diagram  of  a  dry  process
hardboard  mill  and  Figure  11  shows a typical inplant process
diagram  of  a  wet  process  hardboard  mill.    The   principal
difference  between  the two processes is the manner in which the
fibers are carried and formed into a mat.
Chipping
Logs or wood scraps must be either  processed  to  chips  at  the
hardboard  manufacturing plant or converted to chips off-site and
hauled to the mill.  There are several types of chippers utilized
in the industry with disc chippers being the most common.   After
chipping,  chips are screened to control size.  Screens may be of
the rotating, vibrating, or gyrating  types  with  vibrating  and
gyrating screens being the most common.

Chips  are  stockpiled  in the open, under a roof, or enclosed in
chip silos.  As least one mill presently washes chips  to  remove
dirt  and  other  trash which would cause maintenance problems in
the fiber preparation stages.  The  quantity  of  dirt  in  chips
depends  upon  many  factors.   In  the  future/  hardboard mills
project utilizing the complete tree, including bark,  limbs,  and
leaves,  which  will  cause additional dirt to be brought in with
the chips.  There is a general industrial  trend  toward  use  of
lower  quality  fiber  because of the increased demand for timber
                              35

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     1.500 -
o
LiJ
t_J
ra

CD
CtL
Q.

to

UJ

-------
               LOGS

               o
               LOG



             STORAGE
            LOG WASH
             DEBARKER
             CHIPPER
                             "*T*
                             O
                         TO PROCESS
CHIPS
                                           CHIP

                                           WASH
FIGURE 10  -  RAW MATERIAL HANDLING IN THE HARDBOARD INDUSTRY
                       37

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        CHI PS
00
--4
•^1
(30)
— LJ 1 	 IpiAEfe l^- i-tLi
PREHEATERjZ| REFINER 	 1DRYER /^l
(60)JZI3 nzj " (7.5)
CHIPS
	 ».
FIBER
^ 	 ; 	 »*
rERS| V. J | p „ F e «
i r \ i ,
U (0)
PREPRESS
MAT
** 	 te.
, L_^-x TO
* |—^V FINISHING
BOARD
^
          (XX) APPROXIMATE PERCENT MOISTURE
                            FIGURE 11 - TYPICAL DRY PROCESS HARDBOARD MILL

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products, high cost of logs, and their  general  scarcity.   With
the  use  of  lower quality fiber such as tree limbs and bark, it
will become more and  more  desirable  to  wash  chips.   Weather
conditions  during  logging  operations have a significant effect
upon quantity of dirt picked up.  Chip washing is also useful  in
thawing frozen chips in more northern climates.

Fiber Preparation

Prior  to  passing  wood  chips  or  other  fibrous raw materials
through disc pulpers or refiners, it is often expedient  to  give
the  material  some  form  of  pre-treatment  in  order to reduce
subsequent  power  consumption  and   improve   pulp   qualities.
However,  the  extent of the treatment will again depend upon the
nature of the raw material and the end product desired.  Steaming
softens the wood to produce a pulp with fewer broken  fibers  and
coarse  fiber  bundles.   The  fibers  of  pulp  so made are more
flexible and felt together more readily to form a stronger  board
than  pulp  from  wood  that has not been steamed.  However, with
some species, steaming may increase the toughness  of  the  chips
and  thereby  increase  the energy required for defibering.  This
pre-treatment operation is  carried  out  in  digesters  under  a
variety of conditions of time and temperature.

There  are  two  basic  methods  of fiber preparation, but a wide
range of variations exist within each basic  method.   These  two
basic methods are the  (1) explosion process, and  (2) thermal plus
mechanical refining.

In  the  explosion  process,  wood  chips  are  subjected to high
temperature steam in  a  "gun,"  or  high  pressure  vessel,  and
ejected  through  a  quick  opening  valve.   Upon  ejection, the
softened chips burst into a mass of fiber or fiber bundles.   The
process  is  essentially  a  high temperature acid hydrolysis and
lignin softening procedure, and is adaptable to almost any ligno-
cellulosic material,  chips approximately 1.9 cm  (3/4 in) square,
prepared in conventional chippers and screened, are fed into 50.8
cm  (20 in) caliber guns or high pressure vessels.  Each vessel is
filled and closed, and the chips are steamed  to  41.8  atm   (600
psi)  for  about one minute.  The pressure is then quickly raised
to about 69.0 atm  (1000 psi), at 285°C  (550°F) and held for about
5 seconds.  The time  of  treatment  at  this  high  pressure  is
critical,  and  is  dependent  upon  the  species and the desired
quality of the product.  The pressure is suddenly  released,  and
the  wood  chips  burst  into a brown, fluffy mass of fiber.  The
steam is condensed as it enters  the  cyclone  and  the  exploded
fiber  falls  into a stock chest where it is mixed with water and
pumped through washers, refiners, and  screens.   The  yields  of
fiber  from  pulping by the explosion method are lower than those
for other pulping procedures, largely as a result the  hydrolysis
of  hemicellulosic  material under conditions of steaming at high
pressure.  The explosion process is used in  only  two  hardboard
mills in the U.S..
                              39

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By  far the most widely used fiber preparation method consists of
a combination of thermal and mechanical  pulping.   Thermal  plus
mechanical  refining, as its name implies, involves a preliminary
treatment of the raw material with heat in addition to mechanical
action in  order  to  reduce  the  raw  material  to  pulp.   The
mechanical reduction is carried out in disc refiners or attrition
mills  after  the wood chips or shredded raw materials have first
been softened by steaming.

One of the advantages of this attrition mill  method  of  pulping
over  conventional  grinding  lies  in  the  fact  that a greater
variety of species and forms of raw material  may  be  processed,
including  materials  from  roundwood,  slabs, edgings and veneer
residues, as well as materials such as pulp screenings,  shavings
and   sawdust.   furthermore,  with  the  many  possibilities  of
variation in pre-steaming, of plate pattern, of plate clearances,
and  in  a  number  of  refining  steps,  there  is  considerable
flexibility in the production of pulps which possess a wide range
of  properties.  In general, attrition mills such as disc pulpers
produce a good quality of pulp.  A  fast  draining  pulp  can  be
readily produced, coarse fiber bundles and few abraded fibers.

In one process the chips are brought to a temperature of 170°c to
190°C   (340°C  to 375°F) in a period of 20 to 60 seconds by means
of steam pressure between 7.8 and 12.2 atm *(10Q to 165  psi)  and
at  this  temperature  are  passed through a disc refiner.  It is
claimed  that  because  to  the  short  steaming  period,  little
hydrolysis  takes  place  and  that  there is little loss of wood
substance, the yield ranging from 90 to 93 percent.

In the dry process, similar equipment can be used.  However,  the
wood  may be subjected to lower steam pressures of 3.1 to 9.2 atm
(31 to 220 psi) for somewhat longer periods (1 to 2 min) and then
passed through a disc refiner.  In some cases the resin is  added
to  the chips while they are being refined, by pumping it through
a hole drilled through the refiner shaft.

Refiners  (attrition mills) of the disc type have two  discs,  one
stationary and one rotating, or both rotating, for defibering and
refining.  Various disc patterns are available and choice depends
on species, pre-treatment, and the type of pulp desired.  In most
cases,  the  discs  are  made  of  special alloys.  The discs are
usually 60 to 100 cm (23 to 40 in) in diameter and operate at 400
to 1,200 revolutions/min.

Double disc attrition mills, with the discs rotating in  opposite
directions,  do  more  work  on  the fiber and result in a higher
stock temperature,  such equipment, when operating on wood chips,
produces well fiberized material.  Where development of  strength
is desired, further refining may be useful.

The  single  rotating disc mill has certain advantages.  The feed
opening is  more  accessible  and  can  be  made  very  large  to
                              40

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accomodate  bulky materials.  It has fewer moving parts and fewer
bearings than the double disc mill.

Factors which determine the pulp quality  produced  by  attrition
mills  are  properties  of the raw material, pre—treatment, plate
design, plate clearance, rate of feed, consistency,  temperature,
and speed of rotation.  The effect of these variables can only be
determined  by  experiment.   Plate  clearances usually vary from
1.30 mm (0.050 in)  for an initial breakdown of chips  to  a  very
low  clearance  for the final refining.  As the clearance between
the plates is reduced the strength  of  the  pulp  is  increased.
Also  because  of the production of more fines, however, the rate
of drainage is reduced.  An improved  quality  of  stock  may  be
obtained  by  using a plate clearance of about 0.25 mm  (0.01 in),
screening out the  acceptable  stock  and  recycling  the  coarse
material.   This  procedure reduces the power consumption and the
pulp will have a higher percentage of intermediate length  fibers
and  fewer fines.  A certain amount of fines is desirable as they
improve board properties such as rigidity, and provide a smoother
surface.

The power requirements for refiner stock from woods commonly used
vary from about 200 to 800 kw/kkg  (100 to 400  hp/ton)  depending
on species and pre-treatment.

The  consistency  of  pulp  leaving  the  attrition mill in a wet
process hardboard mill may vary over a wide range, but in general
it is between 30 and 40 percent.  Lower  consistencies  are  used
with certain material to prevent feed chokes.  High consistencies
tend to produce better pulps by raising the temperature.

After  conversion  of  the  raw material to a fibrous pulp in the
attrition mills, the pulp may be screened to remove coarse  fiber
bundles,  knots, and slivers.  Some of the coarse material can be
returned to the system for further breakdown.

There  are  various  attrition  mills  on  the  market  for   the
preparation   of   pulp.    The  Asplund  system  has  been  used
extensively for preparation of stock for hardboard  mills.   This
involves the use of a single rotating disc and has the feature of
combining the steaming and defibering in one unit in a continuous
operation.   The  entire  operation is carried out under pressure
and has the advantage that no cooling of the steamed chips  takes
place   prior   to   defibering,  and  foaming  difficulties  are
substantially reduced.  A unit may be expected to process 9 to 45
kkg/day  (10 to 50 ton/day) of dry wood, depending on the type  of
wood and the degree of defibering required.  For hardboard stock,
slight  refining  may be desirable, especially for the removal of
slivers.   When  using  modern  refining  equipment,   subsequent
screening   may  be  unnecessary.   However,  when  screening  is
necessary a vibrating or rotary-type screen may be used.
                              41

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Forming Hardboard

The manuf act lire of hardboard consists basically of reducing  wood
materials  to the fibrous state and putting them back together in
the  form   of   sheets   or   boards   having   properties   and
characteristics  not  formerly  attainable  in  the natural wood.
Before board formation is  started,  it  is  often  desirable  to
introduce  certain  chemical additives to the pulp which increase
the strength, water resistance, and other desirable properties of
hardboard.  The additives to be used and the  amounts  depend  on
the species of wood, degree of refining, and the final properties
desired.   After  the inclusion of additives to the refined pulp,
which may be in the form of either a wet slurry or a  dry  fluff,
the  pulp is ready for delivery to the board former, to begin the
process of reassembling fibers into hardboard.  The formation  or
felting  of  fibers  to form a mat may be done by either the wet-
felting (wet matting)  process or the  air-felting   (dry  matting)
process.

Wet-Felting:   In  the wet process the mat is usually formed on a
fourdrinier type machine similar as those used in  making  paper.
Refined pulp is pumped to the head box of the machine and diluted
with large quantities of water until the mixture, called "stock,"
contains only about one and one-half percent pulp by weight.  The
stock  flows  rapidly  and  smoothly  from  the  head box onto an
endless traveling wire  screen.   Devices  control  the  flow  of
stock,  allowing  it  to  spread  evenly  on  the  screen  as  an
interlaced fibrous blanket which may  be  several  inches  thick,
depending  upon  the desired thickness of the finished hardboard.
The screen, kept level by tension, and table  rolls  carry  stock
onward for about 9 m  (27 ft) while water is withdrawn through the
wire  screen.   The  water  is  first removed by gravity.  As the
screen advances, additional water is removed when it passes  over
one  or  more suction boxes.  At this point, the stock has felted
together into a continuous fibrous  sheet  called  "wetlap."  The
forming screen extends between a number of pairs of press rollers
which  also  have an endless screen travelling around a series of
the paired rollers.  More water is removed as the  press  rollers
gradually  apply  pressure  to  the wetlap, in a process which is
similar to the wringing action of a washing machine.

When the wetlap emerges from press rollers it still  has  a  high
moisture  content   (50 to 75 percent), yet it is strong enough to
support its own weight over a small  span.   At  this  point,  it
leaves  the  forming screen and continues on a conveyor.  The wet
mat is then trimmed to width and cut off to length by a traveling
saw which moves across the traveling mat  on  a  bias,  making  a
square  cut  without  the  necessity  of  stopping the continuous
wetlap sheet.  The thickness of wet mat is normally three or four
times the finished thickness of the hardboard to be produced.  It
still contains a great deal of water.  The wet  mat  may  be  de-
livered  directly  to  a platen press where water is removed by a
combination of pressing and heating or it may be  conveyed  to  a
heated  roll  dryer  where  water is evaporated by heating alone.
                              42

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The direct pressing method is used  to  produce  smooth  one-side
hardboard  (SIS).   The  evaporative drying method is used in the
production of smooth two-side hardboard  (S2SJ.  These  operations
will be described later.

Dry-Felting;    The  main difference between the air-feltingor dry
matting process, and the wet-felting process is that in  the  dry
process  fibers  are  suspended in air rather than in water.  The
unit developed for laying down a continuous mat of dry fibers  is
called  a  felter.   The  prepared  fibers  are fed by volumetric
feeders to the felting unit at a controlled rate.   A  nozzle  in
the unit then distributes fibers to the top of the felter chamber
and  the  fibers  fall  to the floor of the felter.  This snowing
action produces an interwoven mat of fibers,

The floor of the felter is a moving screen which is  synchronized
with the volumetric feeders, and air is sucked through the screen
to  aid  in  the  felting.   As  the mat emerges from the felting
chamber, it has attained the height necessary for  the  thickness
of the board desired.

When  a finished board of 0.32 cm  (1/8 in) is desired, the height
of the mat as it emerges from the felting chamber may be as  much
as  10  to  15  cm   (4  to  6  in).   Once the mat is formed, the
procedure of compressing, trimming, and  sawing  of  the  mat  is
similar  to  that  for the wet process.  However, air-formed mats
prior to pressing are always thicker and softer  than  wet-formed
mats  and  usually  require  more  care  in loading the hardboard
press*

Hardboard press

When the reassembly of wood particles is  completed,  fibers  are
welded  together  into  a  tough, durable grainless board, on the
hardboard press.  Hardboard presses are  massive,  consisting  of
heavy  steel  heads and bases, each of which may weigh 45 JtJcg  (50
ton) or more, held together by steel columns 25 to 30 cm   (10  to
12  in)  in  diameter  and  as  long  as 9 to 12 m (30 to 40 ft),
Between the head and the base of the press are suspended a number
of  steel  platens  which  are  drilled  internally  to   provide
circulating  passages  for  high pressure steam or water which is
used to provide heat necessary to help bond the fibers  together.
Several  hydraulic  rams with a movable head are placed below the
platens and on top of the base to apply pressure  upwards  toward
the  head  of  the  press.   When open, the hydraulic rams are at
their lowest position.  Each platen, except the  top  and  bottom
platens  which  are  fastened firmly to the press head and moving
base, respectively, is individually suspended,  allowing  an  air
space  of 8 to  25 cm  (3 to 10 in) between platens.  The unpressed
mats are placed one on top of each platen so  that  there  is  an
equivalent of a multi-deck sandwich, with the mat located between
the  steel platens.  When the press is loaded, hydraulic pressure
is applied to the rams.  This operation  forces  the  platens  up
against  the  head  of  the  press,  squeezing the mats down to  a
                              43

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fraction of their former thickness.  Pressures exerted  may  vary
from 35 to 103 atm (500 to 1500 psi) depending on the process and
density  desired  in  the finished board.  Most hardboard presses
have 20 openings and 21 platens, so that 20 boards may be pressed
at the same time.  Some presses have as few as ten  openings  and
some as many as 30.  Press sizes vary, but include 1.2 m by 4.9 m
(4 ft by 16 ft), 1.2 m by 2.4 m (4 ft by 8 ft) , 1.2 m by 5.5 m (4
ft  by  18  ft),  and  1.5 m by 4.9 m  (5 ft by 16 ft).  The first
press size is the most common production size.

The combination of heat and pressure applied to mats in the press
welds the fibers together.  The actual amount  of  time  required
for  pressing  and  the  details of temperature and pressure vary
widely, depending on the process and physical properties  in  the
particular hardboard being produced.

To  facilitate loading and unloading the board in the press, most
presses are equipped with  loading  and  unloading  racks,  which
usually  take the form of multi-deck elevators, with one deck for
each opening in the hardboard press.   Mats  are  loaded  on  all
decks  of  a  loading  rack.   When  the hardboard press is open,
impressed mats are fed into the press at the  same  time  pressed
mats are removed at the other end of the press and placed into an
unloading  rack.   Then, while the new boards are under pressure,
unpressed mats are placed into the loading rack and pressed  mats
are  discharged  one at a time from the loading rack and conveyed
to subsequent operations*

Pressing Operations:  There are two  basic  types  of  hardboard,
"smooth  one-side" (S1S) and "smooth two-sides"  (S2S).  In making
S1S hardboard, the cut-to-size mat is delivered  from  the  board
former  onto  a  piece  of screen wire slightly larger in overall
dimensions than the piece of wet mat.   The  wires  carrying  wet
mats are loaded into the decks of the press loading racks and are
loaded  into  the  press  openings.  When the press is closed and
pressure applied, a large  portion  of  water  is  removed.   The
remaining  water  must  be  evaporated  by  the heat of the press
platens.  Temperatures used in the production of  S1S  board  are
around  190°C   (380°F).  The entire process of pressing the board
is carefully controlled by automatic electrical equipment.

When a wet-formed mat is to be used to produce S2S hardboard,  it
is  delivered from the forming machine into a hot air dryer where
surplus moisture is evaporated.  This may  require  from  one  to
four hours depending upon the weight of board being produced.  At
this  stage  the  mat is in large pieces, usually 2 or 3 times as
wide as the hardboard which will ultimately be pressed.  The  mat
is  trimmed  to  the  desired  length and width  (usually slightly
larger than 1.2 by 4.9 m) and  delivered  to  the  S2S  hardboard
press.   At  this point, the board may have less than one percent
moisture content, and it is strong and rigid  enough  to  support
its  own  weight.  Thus, board can be delivered directly into the
press openings and pressed with smooth platens, or  caul  plates,
directly  against both sides.  Since moisture does not have to be
                              44

-------
squeezed and evaporated, the press cycle, which is  from  one  to
four  minutes  for  common  thickness,  is  much shorter than for
comparable thicknesses of S1S board, which requires  a  4  to  12
minute pressing time.  The dried board is much harder to compress
than  the  soft, wet S1S; consequently, hydraulic pressures three
times greater must be applied.  Press temperatures in  excess  of
288°C (550°F) must also be attained.

Dry-formed  mat  may also be used to produce S2S hardboard.  When
this is done, the  fibers  must  be  reduced  to  a  desired  low
moisture  content  prior  to  the board formation.  Most dry air-
formed mats are deposited directly on traveling caul  plates  and
delivered  into  the  press.   These  traveling  caul  plates are
necessary because the air-formed mat is too  fragile  to  support
its  own  weight before pressing*  Once in the press however, the
combination  of heat, pressure, and time  consolidates  the  soft,
fluffy material into a rigid, durable product.

Oil Tempering

After  being  discharged  from the press, hardboard may receive a
special  treatment  called  tempering.   Tempering  consists   of
impregnating the sheets of hardboard by dipping or roller-coating
them  in a bath composed of drying oils and various drying resins
derived from petroleum.

As sheets are removed from the oil bath, they are passed  through
a  series  of  pressure  rollers which increase absorption of the
oils and removes any excess.   The  oil  is  then  stabilized  by
baking the sheet from one to 4 hours at temperatures ranging from
143° to 171°C  (290° to 340°F).  Tempering hardboard increases the
hardness,  strength,  and water resistance, thus making the board
more resistant to abrasion and weathering.

Humidification

Sheets of hardbqard removed from the press or the tempering  oven
are  very  hot  and  dry,  and  the boards must be subjected to a
seasoning operation called "humidification."  otherwise they  may
tend  to  warp  and change dimensions.  Humidification is carried
out by conveying boards through  a  long  tunnel  humidifier,  or
charging  them  in  racks  which  enter  a  chamber  where a high
relative humidity is maintained.  The boards are retained in  the
humidifier until they reach the proper moisture content.
Further Processing

The  final  operation includes trimming the board to the required
size.  Hardboard  may  also  be  finished  by  an  assortment  of
techniques,  including  simulating  wood grain finishes, applying
paint for a variety of uses, embossing, and scoring.
                              45

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Inventory of Hardboard Industry

In 1973, there were 27 manufacturing  facilities  which  produced
hardboard by some variation of the two basic processes.  As shown
in Table 1, 17 of these were variations of the dry process and 10
were  variations of the wet process.  In addition, some hardboard
is produced at 6 insulation board plants,  but  the  waste  water
aspects  of  these  will be considered along with that segment of
the timber products processing category.  It has  been  estimated
that in 1972, the total production of hardboard in the U.S., on a
3.2 mm  (1/8 in) basis, was 0.54 billion sq m (518 billion sq ft).
The  geographical distribution of the hardboard industry is shown
graphically in Figure 12.

From the viewpoint of total utilization of the  forest  resource,
those  segments  of the timber products processing category which
are relatively indiscriminant in terms of the properties  of  the
wood  raw  material  used  are  of  increasing  importance.  High
quality lumber and plywood  are  prized  for  certain  structural
characteristics  which  are  inherent  in  the  structure  of the
harvested tree.  As the timber  products  industry  becomes  more
dependent on smaller, second-growth timber and as the demands for
timber  products  increase,  it becomes more important to develop
those categories of the industry which  can  use  wood  and  wood
residues in a variety of forms and in large quantities.

In  general,  the categories of this type include those which can
use  wood  reduced  to  small  particles  or  fibers   and   then
reconstitute them into useful form.  In its entirety, this is one
of the most rapidly expanding industrial operations in the United
States.  Hardboard production contributes to that growth.  It has
been reported that 16 times as much hardboard was used in 1953 as
compared   with  1929,   The  Forest  Products  Research  Society
reported that hardboard production on a 0.32 cm   (1/8  in)  basis
increase^  from 0.09 billion sq m  (0.96 billion sq ft) in 1948 to
0.14 billion sq m (1.5 billion sq  ft)  in  1955.   In  1968,  27
hardboard  plants in the U.S. produced approximately 0.39 billion
sq m (4.2 billion sq ft) of product.  During the  first  part  of
1973,  plans  for  3  new  dry  process plants were completed and
construction was begun.

A  U.S.  Forest  service  survey  published  in  1964,  based  on
information  collected  in  1962,  established that the amount of
timber consumed in the U.S. has increased to 0.37  billion  cu  m
(13  billion  cu  ft)  annually.   It  projected a demand of 0.79
billion cu m (28 billion cu ft) by the  year  2000  -  more  than
twice the 1962 level - based on a population of 325 million.  The
increased  population must also be sheltered, and experts predict
100 million homes must  be  built  in  the  next  30  years.   If
hardboard  manufacture increases at the same rate during the next
decade as in the last two decades, annual production is projected
to be 0.93 billion sq m  (10 billion sq ft) by 1980.   Ten  plants
with  an  annual  capacity of 39 million sq m (420 million sq ft)
each would have to be completed to meet this demand.
                              46

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CH  I PS
FIBER
                                       DILUTION
                                       WATER
CHIPS
      SCREW
      -FEED
M AT
                                                                           BOARD
                                                     TO ATMOSPHERE
                                                   WET FORMING
                                                   MACHINE
                                                          WET  I—T-\
                                                          PRESS I—L-,/

                                                               '  TO
                                                           I    FINISHING
             WATER IN

             WATER OUT
       (XX)  APPROXIMATE PERCENT  FIBER
             (CONSISTENCY IN PROCESS)
                    FIGURE 12  -  TYPICAL WET PROCESS HARDBOARD MILL

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                          TABLE 7

       INVENTORY  OF  HARDBOARD MANUFACTURING FACILITIES
DRY PROCESS

Anacortes Veneer
Anacortes, Washington

Celotex Corporation
Deposit, New York

Celotex Corporation
Marion, South  Carolina

Celotex Corporation
Paris, Tennessee

Evans Products
Doswell, Virginia

Evans Products
Moncure, North  Carolina

Evans Products
Phillips, Wisconsin

Georgia-Pacific Corporation
Coos Bay, Oregon
DRY-WET PROCESS

Weyerhaeuser Company
Klamath Falls , Oregon
Georgia Pacific  Corporation
Conway, North  Carolina

Masonite Corporation
Spring Hope, North  Carolina

Masonite Corporation
Towanda, Pennsylvania

Pope and Talbot
Oakridge, Oregon

Superwood (Nu-Ply)
Bemidj i, Minnesota

U.S. Plywood
Champion International
Catawba, South  Carolina

U.S. Plywood
Champion International
Lebanon, Oregon

Weyerhaeuser Company
Broken Bow, Oklahoma
WET PROCESS

Abitibi Corporation
Roaring River, North  Carolina
Evans Products
Corvallis,  Oregon

Forest Fibre
Stimpson  Lumber  Company
Forest Grove, Oregon
                               48

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                    TABLE  7  CONTINUED

        (INVENTORY  OF HARDBOARD MANUFACTURING FACILITIES)
Masoriite  Corporation
Laurel, Mississippi

Masonite  Corporation
Ukiah,  California

Superior  Fibre
Superior, Wisconsin
Superwood
Duluth, Minnesota

Superwood
North Little  Rock,  Arkansas

U.S. Plywood
Champion International
Dee (Hood River),  Oregon
WET-DRY  PROCESS

Abitibi  Corporation
Alpena,  Michigan
WET-DRY HARDBOARD PLANTS
OPERATED  IN  CONJUNCTION
WITH INSULATION BOARD PLANTS
Boise  Cascade
International  Falls,  Minnesota

Temple  Industries
Diboll,  Texas

U.S. Gypsum
Danville,  Virginia
U.S. Gyps urn
Greenville,  Miss issippi

U.S. Gypsum
Pilot Rock,  Oregon

Weyerhaeuser Company
Broken Bow. Oklahoma
                                49

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CJl
o
                             LEGEND
                                 WET PROCESS
                                 DRY PROCESS
                                 DRY-WET PROCESS
                                 WET- DRY  PROCESS
                                 WET-DRY/ INSULATION
                        FIGURE 13 - GEOGRAPHICAL  DISTRIBUTION OF HARDBOARD MANUFACTURING
                                    FACILITIES  IN THE UNITED STATES

-------
Somewhat akin to  the  saw  mill  part  of  the  timber  products
processing  industry,  hardboard operations are spread nationally
with some production of each kind in each forest  region  of  the
U.S..   The  hardboard  and particle board industries can use the
residues from other wood working plants and  accordingly  provide
opportunities to reduce the cost of other products and expand the
development of completely integrated wood industries.

It is anticipated that there will be two major factors which will
influence the location trend of future hardboard plant additions.
The  trend  toward  integrated  forest  product  complexes, which
involve pulp and paper, plywood, hardboard operations, and  other
operations all contained at one location is expected to increase.
Installations  such as these will be predicated upon the benefits
derived from logistics and economics.  Currently, about one-third
of the hardboard plants are owned by  one  of  the  major  forest
industry  companies,  and this percentage is expected to increase
moderately in the near future, which  will  no  doubt  have  some
impact on the location trend.

The   other   major  factor  influencing  growth  trend  is  that
associated with supply and demand, with new plants being  located
where  there  is  demand  predicted  on  the  dynamic  growth and
expansion areas.  Raw material availability and  price  may  have
some impact on the development of this particular growth trend.

By  far  the  most  dynamic  growth areas are the South Atlantic,
South Central, and Pacific Coast regions.  It is anticipated that
the growth trend will intensify in these three areas  during  the
next decade and probably on into the 1990's.

Due to the anticipated demand for hardboard production, it is not
expected  that  any  operations will be phased out prior to 1980.
After this time, however, wet  process  plants  in  the  capacity
range  of  4.6  to 9.3 million sq m  (50 to 100 million sq ft)  may
become economically marginal.

WOOD PRESERVING

The wood preserving process is one in which round and  sawn  wood
products  are  treated  by  the  injection of chemicals that have
fungistatic  and   insecticidal   properties   or   impart   fire
resistance.

The  most  common  preservatives  used  in  wood  preserving  are
creosote, pentachlorophenol, and various formulations  of  water-
soluble,  inorganic chemicals, the most common of which are salts
of  copper,  chromium,  and   arsenic.    Fire   retardants   are
formulations  of  salts, the principal ones of which are borates,
phosphates, and ammonium compounds.  Eighty percent of the plants
in the U.S. use at least 2 of the 3 types of preservatives.  Many
treat with one or 2 preservatives plus a fire retardant .
                              51

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Treatment is accomplished  by  either  pressure  or  non-pressure
processes.    Pressure   processes   for   treating   wood   with
preservatives  employ  a  combination  of  air  and   hydrostatic
pressure  and  vacuum.   Differences  among  the various pressure
treating processes used are  based  mainly  on  the  sequence  of
application   of  vacuum  and  pressure.   Nonpressure  processes
utilize open tanks and either hot or cold preservatives in  which
the  stock to be treated is immersed.  Employment of this process
on a commercial scale to  treat  timbers  and  poles  is  largely
confined  to the Rocky Mountain and Pacific regions, particularly
the latter.  In the East, the process is used to treat lumber and
posts.  The conditioning method that must be employed to  prepare
stock  for  preservative  treatment is partially dependent on the
species of wood.  Some species, such as the southern  pines,  are
conditioned  by  a  process  in  which  the  stock  is steamed at
approximately 118°C (245°F) for periods of from  1  to  16  hours
preparatory  to  preservative  treatment.   The  purpose  of this
process, which is normally carried out  in  the  same  retort  in
which  the  actual  injection  of  preservative  is  subsequently
performed, is to reduce the moisture content of green wood and to
render the wood more penetrable, thus improving  the  quality  of
the  preservative  treatment.   Other species, i.e., Douglas fir,
are conditioned  for  the  same  purposes  by  a  process  called
Boultonizing,  in  which  the  wood is heated under vacuum in the
retort at 82° to 104°c  (180°  to  220°F)  prior  to  preservative
injection.  Boultonizing is not used where the preservative is of
the water-borne type.

Waste  water  generated in steam conditioning is composed of both
steam condensate and water removed from the  wood.   Waste  water
from  the  Boultonizing process is composed only of water removed
from the wood.  Both waste streams are contaminated by  the  pre-
servative  used,  and,  where  the same preservative is used, the
difference between them is primarily a quantitative one.

A process flow diagram for a typical plant using steam condition-
ing is shown in Figure  14.

Consumption data for the principle preservatives for  the  5-year
period  between  1967 and  1971 are given in Table 8.  In terms of
amount used, creosote in its various forms is the most important,
followed   in   order   by   pentachlorophenol   and    salt-type
preservatives.   Among  the  latter,  the  CCA   (copper-chromium-
arsenic) formulations account for most of that used.

The general trend in preservative use is a decrease  in  creosote
consumption  and  an increase in the use of pentachlorophenol and
salt-type preservatives.  This trend  is  expected  to  continue.
Consumption of fire retardants has been relatively stable for the
past  five, years,  but  it  is anticipated that it will increase
significantly as existing building codes are modified  to  permit
the  use  of  fire  retardant  treated  wood  in  lieu  of  other
flameproof construction materials.
                              52

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FIGURE 14 - PROCESS FLOW DIAGRAM FOR A TYPICAL WOOD-PRESERVING PLANT
            (COURTESY OF ALBERT H.  HALFF ASSOCIATES,  INC.,  DALLAS,  TEXAS)

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                                TABLE  8

      CONSUMPTION  OF PRINCIPAL   PRESERVATIVES AND  FIRE  RETARPANTS

        OF REPORTING PLANTS  IN THE_UNITED STATES,  1967-1971
                                            Year
Material
 (Units)    1967_   1168    1969   19.70.   1971_
Creosote

Creosote-
Coal Tar

Creosote-
Petroleum

Total
Creos ote

Total
Petroleum

Penta-
chlorophenol

Chromated
Zinc Chloride
CCA
ACC
Pyresote
Non-Com
FCAP

Osmose  Flame
Proof

Other
Solids
Million
Liters

Million
Liters

Million
Liters
329    293    274     256     242
216    219
206
229    218
Million
Liters      559
135    121    115     125     118


       518    485     475     441
Million
Liters      279
       279     258     286    307
Million
Kilograms    11.2    12.0   11.6   12.9   14.5
Million
Kilograms
  0.8    0.7     0.6     0.7
Million
Kilograms     1.0     1.4    2.1    2.7
                 0.6
                               3.9
Million
Kilograms
  0.6    0.5     0.4     0.4    0.5
Million
Kilograms     1.3    1.7    1.1    1.2     1.2

Million
Kilograms     2.4    2.7    3.4    3.1     2.8

Million
Kilograms     2.4    1.8    2.0    1.2     1.0

Million
Kilograms     2.0    1.8    1.8    2.0     2.4

Million
Kilograms     2.7  _  2.8    2.3    1.7     1.7
Note:   Data are based on information  supplied by approximately
        357 plants for each year.
                                      54

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Inventory of the Wood Preserving Segments

The  wood  preserving  industry  in  the  U.S.  is  composed   of
approximately  390  treating  plants,  315  of which use pressure
retorts.  Most of the plants are  concentrated  in  two  distinct
regions.   The  larger region extends from East Texas to Maryland
and corresponds roughly to the natural range of the southern pine
which is the major species utilized.  The second concentration of
plants is located along the Pacific Coast, where Douglas fir  and
western  red  cedar  are  the  species of primary interest to the
industry.  Only 23 percent of the plants in the U.S. are  located
outside  these  two  regions.  The distribution of plants by type
and location is given in Table 9.

The production of treated wood is very responsive to the  general
state  of  the  national  economy, particularly the health of the
construction industry.  Production overall decreased from 1967 to
1971  (Table 10), but is expected to show  a  sharp  increase  for
1972.

The  volume  of  wood  treated  with  creosote showed the largest
decrease during the 1967 to 1971 period, and accounted  for  most
of   the   decrease  in  total  production.   Wood  treated  with
pentachlorophenol registered a slight increase during the period,
while that treated with CCA-type preservatives  increased  almost
four-fold.   Production  of  fire-retardant treated wood remained
essentially constant-  These trends  are  expected  to  continue,
except  that  an  increase  in  the  production of fire-retardant
treated wood is anticipated.
                              55

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                             TABLE
WOOD PRESERVING PLANTS  IN THE UNITED  STATES BY STATE  AND TYPE
                              (1971)




                         C o mme r c i a1
Railroad  and Other

NORTHEAST
Connecticut
Delaware
Dist. of Columb
Maine
Maryland
Massachuset ts
New Hampshire
New Jersey
New York
Pennsylvania
Rhode Island
Vermont
West Virginia
TOTAL
NORTH CENTRAL
Illinois
Indiana
Iowa
Kans as
Kentucky
Michigan
Minnesota
Missouri
Nebraska
North Dakota
Ohio
Wis cons in
TOTAL
SOUTHEAST
Florida
Georgia
North Carolina
South Carolina
Virginia
TOTAL
Pressure

0
1
ia 0
0
6
1
1
4
5
6
1
0
3
28

6
6
0
0
6
4
3
7
0
0
7
3
42

23
24
18
11
15
91
Non-
Pressure

0
0
0
0
0
0
0
2
0
0
0
0
0
2

0
0
0
0
0
2
5
5
0
0
0
0
12

1
1
0
0
1
3
Pressure
and Non-
Pressure

0
0
0
0
0
0
0
0
0
0
0
0
1
1

0
0
0
0
0
0
2
0
1
0
0
1
4

1
2
0
0
1
4
Pressure

0
0
0
0
0
0
0
0
0
1
0
0
0
1

0
0
0
0
0
0
1
0
0
0
0
1
2

0
0
0
0
0
0
Non-
Pressure

0
0
0
0
0
0
0
0
1
0
0
0
1
2

1
0
1
0
0
0
0
0
0
0
0
1
3

0
0
1
0
0
1
Total
Plants

0
1
0
0
6
1
1
6
6
7
1
0
5
34

7
6
1
0
6
6
11
12
1
0
7
6
63

25
27
19
11
17
99
                              56

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TABLE
CONTINUED
 Commercial
          Railroad and Other



SOUTH CENTRAL
Al ab a ma
Arkansas
Louisiana
Mississippi
Oklahoma
Tennessee
Texas
TOTAL
ROCKY MOUNTAIN
Arizona
Colorado
Idaho
Montana
Nevada
New Mexico
South Dakota
Utah
Wyoming
TOTAL
PACIFIC
Alaska
California
Hawaii
Oregon
Washington
TOTAL
UNITED STATES
TOTAL


Pressure

22
11
21
18
6
6
27
111

1
2
3
2
0
1
0
0
1
10

0
8
3
6
7
24
306


Non-
Pressure

1
0
0
1
0
1
3
6

0
0
3
3
0
0
0
1
0
7

0
0
0
0
5
5
35

Pressure
and Non-
Pressure

0
1
1
3
0
0
2
7

0
.0
0
1
0
0
1
1
1
4

0
2
0
4
4
10
30



Pressure

0
0
0
0
0
1
2
3

0
0
0
2
0
1
0
0
0
3

0
0
0
0
0
0
9


Non-
Pressure

0
0
0
0
0
0
0
0

0
0
1
0
0
0
0
0
0
1

0
2
0
0
1
3
10


Total
Plants

23
12
22
22
6
8
34
127

1
2
7
8
0
2
1
2
2
25

0
12
3
10
17
42
390

          57

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01
CD
                                                       TABLE 10



                MATERIALS TREATED IN  THE_UNITED STATES,  BY PRODUCT AND PRESERVATIVE,  1967-1971
(Note:


Pres ervative

Creosote and
Creosote-Coal
Tar


Creosote-
Petroleum



Petroleum-
Pentachloro-
phenol


Chromated
Copper
Ars enate
Components may not add to totals due to rounding.)
Thousand Cubic Meters


Year
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
1967
1968
1969
1970
Poles
and
Piling
1,636
1,456
1,330
1,315
1,172
30
27
18
18
15
950
927
919
1,074
1,157
5
11
35
42

Railroad
Ties
1,683
1,712
1,497
1,650
1,856
808
125
694
806
775
7
6
5
10
4
1
0.2
1
1
Lumb er
and
Timbers
504
528
451
357
342
82
97
81
62
45
446
54
450
436
430
146
197
254
366

Fence
Posts
184
184
175
181
193
68
45
42
32
27
290
224
212
194
233
3
4
7
9


Other
100
100
93
78
70
12
11
7
9
9
186
168
142
146
143
0.5
4
8
10


Total
4,146
3,980
3,545
3,587
3,6326
1,000
905
849
926
871
1,879
1,846
1,729
1,864
1,967
217
306
306
4287

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01
10
                                                     T ABL E  10  CONTINUED


                                                          Thousand  Cubic Meters
Preservative

Fluor Chrome
Arsenate
Phenol


Creosote-
Pentachloro-
phenol


Chromated
Zinc
Chloride


Acid
Copper
Chromate

Year
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
Poles
and
Piling
2
2
19
0.1
0.3
222
211
187
140
97
0.1
	
0.6
— —
	
_ — —
	
	
	
— _
Railroad
Ties
6
2
2
2
2
0.1
—
— —
	
—
»» —
„ —
— _
	
	
— — —
_ —
	
	
	
Lumb er
and
Timbers
346
231
193
128
173
0.9
9
13
11
17
29
29
26
22
20
61
48
37
31
56
Fence
Posts
5
5
3
1
1
0.5
1
0.5
1
0.1
_.__
___
	
	
	
0.1
— _—
0.1
	
0.1
Other
37
28
28
17
31
1
0.8
0.2
	
— —
6
0.6
0.2
	
0.1
__—
	
	
	
___.
Total
397
268
245
142
208
225
222
200
152
114
35
29
27
22
21
61
48
37
31
56

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TABLE  10 CONTINUED
Thousand Cubic Meters
Preservative

Fire
Retardants



All
Others




All
Preservatives

Year
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
1967
1968
1969
1970
1971
Poles
and
Piling
„_
___
	

	
12
15
13
12
4
2,857
2,649
2,522
2,600
2,492
Railroad
Ties
3
2
0.3
2
_— -
._—
0.1
	
0.1
	
2,508
2,447
2,199
2,469
2,639
Lumber
and
Timbers
99
94
104

10-0
47
18
72
3
19
1,716
1,772
1,687
1,576
1,694
Fence
Posts
1|ti_t
— «.
— -

	
6
4
3
62
3
595
466
443
428
472
Other
32
42
30

37
7
6
13
6
2
382
360
323
292
305
Total
134
138
134

138
71
43
102
83
28
7,538
7,695
7,175
7,366
7,602

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                           SECTION IV

                   INDUSTRY SUBCATEGORIZATION
INTRODUCTION

In developing effluent limitations guidelines  and  standards  of
performance for new sources for a.given industry, a judgment must
be  made  by EPA as to whether effluent limitations and standards
are appropriate for different subcategories within the  industry.
The  factors considered in determining whether such subcategories
are needed for the segments of  the  timber  products  processing
category of point sources are:

1.  Products Produced

2.  Manufacturing Process Employed

3.  Raw Materials               .

4.  Plant Age

5.  Plant Size

.6.  Wastes Generated

7.  Treatability of Waste Waters

8,  Air Pollution Control Equipment


Based upon an intensive literature search, plant inspections, and
communications  with  the  industry,  it  is  the judgment of the
Agency that the timber products   processing  category  should  be
subcategorized  by  product   and   by  the  type of manufacturing
process employed.   A  discussion of  these  and  other  factors
considered in this  judgment follows.

FACTORS IN INDUSTRY SUBCATEQQRIZATION

Type of Products Produced

As  discussed  in   section III, there are wide differences in the
products manufactured by  the segment  of  the  timber   products
processing category being considered.  Logs are barked to produce
an  intermediate  product  common to most of the timber  products
processing  category.   This  intermediate  product  is   further
processed  into  veneer  and  plywood,  hardboard, and treated or
preserved wood.  Because of the readily apparent disparity  among
these products it is initially concluded that the timber  products
processing  category  can  be subcategorized on the basis of the
                               61

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type  of  product   produced.    Thus,   the   initial   industry
subcategorizations  established  are: (1) barking, (2) veneer and
plywood manufacture,  (3)  hardboard  manufacture,  and  (4)   wood
preserving.  While barking does not produce a commercial product,
it  is a necessary initial operation throughout the industry, and
for the purposes of this  report  is  considered  to  produce  an
unfinished or intermediate product.

Manufacturing Process Employed

The  manufacturing  process  used  in  the  production of a given
product have been found to be so  different  as  to  support  the
previous   subcategorization   and   form  a  basis  for  further
subcategorization in certain instances.

The process of barking or removing the bark layer from  logs  may
be carried out either by mechanical abrasion or hydraulic removal
as   previously   discussed.   These  processing  operations  are
different from those used in any other segment of  the  category.
Hence, this tends to reinforce the initial segregation of barking
as a subcategory.

The  principal  processes  employed  in  manufacturing veneer and
plywood are unlike  those  employed  in  other  segments  of  the
category.   The  operations  of log conditioning, veneer cutting,
veneer drying, veneer preparation, gluing, pressing and finishing
have been previously described and are unique to this segment  of
the   category.    This   reinforces   the  previous  preliminary
conclusion  that  its  veneer  and  plywood  segment  should   be
considered  separately  from  the  other  segments  of the timber
products category.  Also, since the veneer manufacturing  process
is  a  separate  operation  with waste water quality and quantity
generation differences, and plywood manufacture is a process  not
always  occurring  in  the  same  plant, they logically fall into
distinct subcategories.

One method of log conditioning employs live  steam  to  heat  the
logs  directly  and  another  uses steam to heat the conditioning
vats resulting in significant discharges of process waste waters.
Other log conditioning methods do not produce large discharges of
process waste waters.  Available data indicates that an allowance
may be necessary in the veneer subcategory for  those  operations
which  use direct steam contact to condition wood prior to veneer
cutting, and  which  are  currently  unable,  or  chose  not  to,
implement other conditioning methods prior to 1983.

The  manufacturing  processes  used  to manufacture hardboard are
unique within the timber  products  category.   These  processes,
which  include  chipping, fiber preparation, forming  (either wet-
or air-felting), pressing, tempering  and  finishing,  have  been
described   in   detail  in  Section  III.   This  uniqueness  of
manufacturing  operations  tends  to   confirm   that   hardboard
manufacturing  should  be considered separately within the timber
products processing category.
                              62

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There are two significantly different manufacturing processes  in
the\  hardboard   industry  which  afford  a  basis  for  further
subcategorization.  These are the dry felting process and the wet
felting process.  In  the  dry-felting  process  the  fibers  are
suspended  in  air as the mat is formed, while in the wet-felting
process the fibers are  suspended  in  water.   There  is  little
process  waste  water  generation  from  the dry-felting process,
while  there  is  a  continuous  and  substantial   waste   water
generation from the wet-felting process.

Wet-felting   (wet process) hardboard mills may press board either
dry or wet.   If the board is to be pressed dry it  is  oven-dried
before pressing,  since there is only one existing hardboard mill
which  produces  hardboard alone by wet-felting and dry pressing,
it does not warrant consideration as a separate category.

There are several insulation board mills which produce  hardboard
by  the wet process followed by dry pressing.  Because insulation
board mills will be considered in a future regulation and because
the interrelationship between the manufacture of insulation board
and hardboard, if any, is unknown at this time, these mills  will
be addressed  by a future regulation.

In  wet  process  hardboard  mills,  fiber preparation is a major
factor affecting waste water characteristics.  Two mills  utilize
the  explosion  process  for fiber preparation, thus causing sub-
stantially more BOD to be released.  However, both of these mills
have installed evaporators to handle this high BOD process  waste
water  and  their overall waste discharge is as low or lower than
other wet process mills.   All  other  mills  use  a  combination
thermal-mechanical  process for fiber preparation.  The degree of
fiber preparation will depend upon many  factors  including  wood
species,  inplant  processes,  and final product.  There are even
separate fiber preparation lines for boards that are made  up  in
layers  with  the  degree  of  fiber  preparation  for each layer
dependent upon the product to be produced.  The effect  of  fiber
preparation on waste water flow and composition is not sufficient
in  itself to  be used as grounds for subcategorizing the industry.

Wood  preserving consists of treating round  (barked) or sawn wood
products by infusing them with chemicals to protect the wood from
insects, microorganisms, fungi and fire.  The chemicals used  may
be  either  oil  type  or  salt   (water soluble) type, and may be
infused into  the wood by soaking or pressure treatments, indirect
steaming,  prior  to  chemical  infusions,  the   wood   may   be
conditioned by direct heating, by a vacuum heating process called
Boultonizing,  or  the  wood  may not be conditioned at all.  The
considerable  differences between the processes employed  in  wood
preserving and the other segments of the timber products category
clearly  confirm  the preliminary conclusion that wood preserving
should  be  considered  separately  from  the  remainder  of  the
segment.
                              63

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Water  use  and  waste  characterization,  related to the process
employed, and discussed in Section V,  indicates  that  the  wood
preserving  portion  should be further divided for the purpose of
establishing effluent guidelines and standards.  The waste  water
volume  generated  during the conditioning step prior to infusing
chemicals into the wood appears to offer a logical separation  of
the  portion.  The volume of process waste water generated in the
direct steam conditioning process is  relatively  large  so  that
treatment   with   discharge  of  the  treated  effluent  appears
necessary.  The process waste  water  volumes  generated  by  the
Boulton conditioning process are relatively small and can be more
readily  managed,  opportunities for reuse of the small volume of
waste water, generated in the treating of wood with water soluble
preservatives, are available, unless  the  salts  are  used  with
steam  conditioning.   The  nonpressure treatment methods produce
almost no process waste water and can also  be  classified  along
with Boultonizing in this regard.  Therefore, the wood preserving
segment  of  the  timber  products category can be subcategorized
into (1)  processes using direct steam conditioning of stock to be
treated,   (2) processes using Boultonizing,  and  (3)   other  wood
preserving processes, inclusively.

Raw Materials

Numerous species of wood are used in the industry and waste water
characteristics  may  vary somewhat with raw material.  Softwoods
in contact with water (particularly hot water), release more wood
sugars  than  do  hardwoods.   Within  the  broad  categories  of
softwood  and  hardwood  there are also many species with varying
leaching characteristics.  In addition, it is  known  that  minor
process  variations  are  often  dictated  by  the  type  of  raw
material.  For example, hardwood logs  may  require  a  different
type of conditioning than species of softwood do.

While  it  would  be  expected that different waste water charac-
teristics result from different raw  materials,  it  is  observed
that  volumes  of waste waters vary only with process variations.
The  control  and  treatment  technology  applied  within   these
segments of the industry consist to a large degree of recycle and
containment  and is more a function of waste water volume than of
pollutant concentration,   Therefore,  dif ferences  according  to
species  do  not  significantly  affect the degree to which waste
waters can be treated or controlled.

Thus, while there are a number of  distinctions  related  to  raw
material  used  within  the  industry, the data generated in this
study indicates that these differences are insufficient to become
a basis for further subcategorization.

Age of Facility

The age of the manufacturing facility has been  considered  as  a
factor   for  subcategorization  of  the  industry.   Barking  is
accomplished by a variety of processes  and  ages  of  equipment.
                              64

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within  the  group  of processes which use mechanical abrasion to
remove the bark, th^re appears to  be  no  change  in  the  water
pollution  vectors attributable to age of equipment.  Similarily,
the age of hydraulic barkers has no determinable impact on  waste
water pollutants.

The  veneer  and  plywood subcategories include a number of older
manufacturing facilities.   The  softwood  plywood  manufacturing
subcategory,  however,  has  been experiencing substantial growth
for the past 20 years, and  numerous  new  facilities  have  been
constructed.   The  southeastern  U.S.,  the  main  area  for new
development, contains many of the  newer  plywood  plants.   Even
though  the  ages  of plants vary, the ages of various components
within a plant are not necessarily reflected in installation  age
as equipment is constantly being modernized and replaced.

A. review of information available and data from the plants in the
hardboard subcategory indicates that plant age has no significant
relationship to waste water generation, quality or quantity.

Within  the hardboard subcategory, the major effects of plant age
are higher equipment maintenance costs and possible  difficulties
involving  the  installation of recycle systems, but not in waste
water flows or concentration.

In the wood preserving manufacturing sutcategory, while plants of
varying ages exist, there is no consistently  defensible  measure
of the effect, of plant age on waste water generation or control.

Plant Size

Plant  size  has been considered as a basis for subcategorization
of the timber products  processing  category  and  this  analysis
indicates that no,subcategorization should be made on this basis.

The  relative  quantity  of  process  waste water pollutants from
barking  operations  generally  are  not  size-sensitive  as  the
installation  of additional duplicate units is required to handle
larger  capacities.   The  size  of  mills  within  the   plywood
subcategory  can   vary  drastically  from  "backyard" operations
producing 200,000 sq m/yr  (2 million sq ft/yr) of  plywood  to   a
large  plywood  mill  producing  56  million sq m  (600 million sq
ft/yr).  Since the volume of waste water produced by  a  mill  is
largely  proportional  to  the  size  of  the  mill,  control and
treatment are  similarly  proportional.   Hence,  plant  size  is
rejected as a possible element for subcategorization.

within  the  hardboard  subcategory,  it has been determined from
existing data and from on-site inspections that,  other  than  in
volumes of process waste water, plant size has no effect upon the
waste  water  characteristics  and, therefore, does not present  a
rational base for subcategorization.  Plant size will only affect
costs of treatment as economies of scale for  larger  plants  may
show a generally a lower unit cost than for small plants.
                              65

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Wastes Generated

While   there   are  distinct  differences  in  the  quality  and
characteristics of the various  waste  waters  generated  in  the
timber products processing category, a careful examination of the
information   in  Section  V  shows  that  the  most  significant
differences are quantitative, and are directly related to product
manufactured and manufacturing process employed.  As an  example,
variation  in  waste  generated  in  the hardboard portion of the
industry is directly related to the two  different  manufacturing
processes  utilized  in  making hardboard.  The waste water flow,
excluding cooling water, from a  typical  dry  process  hardboard
mill  will  consist  of a discharge of less than 1,890 I/day  (500
gal/day).  This compares with a waste  water  flow  of  1,500,000
I/day  (378,000  gal/day)  from  a  typical wet process hardboard
mill.  Since wastes generated are similarly related  to  products
and   proce ss es   in   the   remainder   of   the   industry,   a
subcategorization on this basis is not indicated, because  it  is
effectively accomplished by manufacturing process employed.

Treatabilitv of Waste Waters

The  waste  waters  generated  by  the  barking, veneer, plywood r
hardboard-dry process, and hardboard-wet process portions of this
segment contain as major pollutants, BOD  and  suspended  solids.
These  parameters  are  usually  treated  by  biological methods.
waste waters generated by the  wood  preserving  portion  of  the
segment  may include, in addition to the above listed parameters,
pollutants  such  as  COD,  heavy  metals,  phenols,   and   high
concentrations  of oil and grease.  This difference is considered
in subcategorization*

Air Pollution Control Equipment

Air pollution is  not  a  major  problem  in  this  manufacturing
segment.  Air pollution and its control is not a major problem in
this  segment  of  the  timber  products processing industry.  In
situations where  air  pollution  problems  exist,  the  type  of
control  equipment required may be a venturi type scrubber.  This
system  can  be  operated  as  a  closed  system   with   limited
requirements   for   blowdown,   and,   therefore,  the  industry
subcategorization should not be  be  affected  by  air  pollution
equipment.
                              66

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SUMMARY OF SUBCATEGORIZATION                              /

The  segments  of the timber industry considered in this dpcument
have been separated into  the  following  subcategories  for  the
purpose of establishing effluent guidelines and standards.  These
subcategories are defined as;

    1.  Barking.  The barking subcategory includes the operations
which  result  in  the removal of bark from logs.  Barking may be
accomplished by  several  types  of  mechanical  abrasion  or  by
hydraulic force.

2.   Veneer*  The veneer subcategory includes the operations used
to convert barked logs or heavy timber into thinner  sections  of
wood known as veneer.

3.   Plywood.  The plywood subcategcry includes the operations of
laminating layers of veneer to form finished plywood.

<*.   Hardboard  -  Dry  Process.   The  dry   process   hardboard
subcategory   includes   all   of  the  manufacturing  operations
attendant to the production of  finished  hardboard  from  chips,
sawdust,  logs,  or  other  raw  materials, using the dry matting
process for forming the board mat.

5.   Hardboard  -  wet  Process.   The  wet   process   hardboard
subcategory   includes   all   of  the  manufacturing  operations
attendant to the production of  finished  hardboard  from  chips,
sawdust,  logs,  or  other  raw  materials, using the wet matting
process for forming the board mat.

6.  Wood Preserving.  The wood  preserving  subcategory  includes
all  wood  preserving processes in which steaming or boultonizing
is not. the predominant method of conditioning,  all  non-pressure
preserving  processes, and all pressure or non-pressure processes
employing water borne salts, in which steaming or vapor drying is
not the predominant method of conditioning.


7.   Wood  Preserving  -  Steam.    The   wood   preserving-steam
subcategory   includes   all  processes  that  use  direct  steam
impingement on the wood  being  conditioned  as  the  predominant
method of conditioning, discharges resulting from wood preserving
processes  that  use  vapor drying as a means of conditioning any
portion of their stock, discharges that result from direct  steam
conditioning  wood  preserving processes that use fluor-chromium-
arsenic-phenol treating solutions  (FCAP) ,  discharges  resulting
from direct steam conditioning processes and procedures where the
same  retort  is  used  to treat with both salt-type and oil type
preservatives, and discharges  from  plants  which  direct  steam
condition and apply both salt type and oil type treatments to the
same stock.
                              67

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8*    Wood  Preserving  -  Boultonizing.   The  wood  preserving-
boultonizing subcategory covers those wood  preserving  processes
which  use  the  Boulton  process  as  the method of conditioning
stock.
                                68

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                            SECTION V

              WATER USE AND WASTE CHARACTERIZATION
LOG BARKING
The water employed in hydraulic barking must be free of suspended
solids to avoid clogging nozzles.  Results  of  analyses  of  the
effluent from a hydraulic barking installation are shown in Table
11.   The  total  suspended  solids content in the discharge from
hydraulic barking ranges from 521 to 2,362 mg/1, while BOD values
range between 56 and 250 mg/1.

Results of an analysis of the effluent from a drum barker is also
given in Table 11.  Total  suspended  solids  concentrations  are
only slightly higher in a drum barker than in a hydraulic barker,
but BOD values are significantly higher.  Drum barking waters are
often  recycled,  which  accounts  for part of the increase.  The
higher BOD values are also due to a longer  contact  between  the
bark  and the water and to the grinding action which is absent in
hydraulic barking.

BOD values may also be affected by the species of wood barked and
by the time of the year in which the log is cut.

VENEER AND PLYWOOD MANUFACTURING

Water usage varies widely in the veneer and  plywood  portion  of
the  industry, depending on types of unit operations employed and
the degree of recycle and reuse of water practiced.  In  general,
total water usage is less than 3.15 I/sec  (50 gal/min) for a mill
producing  9.3 million sq m/yr (100 million sq ft/yr).  There are
plants presently being  designed  to  recycle  all  waste  water,
however,  none are now in operation.  Considerable effort can, in
any case, be made to reduce the  amount  of  waste  water  to  be
discharged  or contained.  The amount of information available on
volumes and characteristics of waste waters from the industry  is
minimal.   Data  cited  in  waste water characterization is based
mostly on data  from  the  literature,  information  supplied  by
individual  mills,  and  sampling  and analyses conducted for the
purposes of this study.  Because the volumes  that  are  involved
are  small,  attention  has  been directed to finding methods for
reducing the volumes and ways of handling process water in such a
way as to eliminate discharges.
In veneer and plywood mills,
operations:
water  is  used  in  the  following
                              69

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                          TABLE  11

               ANALYSIS OF DEBARKING EFFLUENTS
                   Total
                 Suspended
       Type of    Solids
Mill  Debarking   (mg/1)
Non-Set
Solids   BOD5
(mg/1)  (mg/1)
Color Units
1
2
3
4
5
6
7
/
8
9
10
11
Hydraulic
Hydraulic
Hydraulic
Hydraulic
Hydraulic
Hydraulic
, i j
Hydraulic
Hydraulic
Drum
Drum
Drum
2,362
889
1,391
550
521
2,017
9 nnn
z , uuu
600
2,017
3,171
2,875
141
101
180
66
53
69
F200

41
69
57
80
85
101
64
99
121
56
Q7
y i
250
480
605
987
Less than 50
Less than 50
Less than 50
Less than 50
Less than 50
Less than 50


35
20
Less than 50
Less than 50
                                  70

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             (1)  Log conditioning
             (2)  Cleaning of veneer dryers
             (3)  Washing of the glue lines
                 and glue tanks
             (4)  Cooling

Figure  15  presents  a detailed process flow diagram.
use and waste characteristics for each  operation  are
below.
The water
discussed
Log Conditioning

Veneer  and  plywood  manufacturing  operations  use two distinct
types of log conditioning systems.  These systems  are  discussed
in  Section  III, and are referred to as steam vats and hot water
vats.  In the South about 50 percent of the plants use steam vats
and 50 percent use hot water vats.  In the  West,  however,  only
about  30  percent of the plants use any kind of conditioning and
these plants use steam vats almost exclusively.

The only waste water from a steam vat is  from  condensed  steam.
This  water  carries  leachates  from  the  logs  as well as wood
particles.  Table 12 presents the results of  analyses  of  waste
waters  from  steam  vats.   The  magnitudes  of these flows vary
according to the size and number of vats.  A plant producing 9.31
million sq m/yr  (100 million sq ft/yr) of plywood on  a  9.53  mm
(3/8 in) basis has an effluent of about 1.58 to 3.15 I/sec  (25 to
50  gal/min).   A  southern  plywood  mill   (Plant  A,  Table 20)
produces a BOD load of 2,500 kg/million sq m  (515  Ib/million  sq
ft) of production on a 9.53 mm  (3/8 in) basis, and a total solids
load  of 29,200 kg/million sq m of production on a 9.53 mm  (6,000
Ib/million sq ft) (3/8 in) basis.

A hot water vat conditions the log with hot water  heated  either
directly with steam or by means of heating coils with steam, oil,
or  other heat sources.  When the vat is heated indirectly, there
is no reason for  a  constant  discharge.   Hot  water  vats  are
usually  emptied  periodically, regardless of heating method, and
the water and the solids that build up in the  closed  system  is
discharged and replaced with clean water,  some plants settle the
spent  waste  water  and  pump  it  back into the vats.  Chemical
characteristics for hot water vats for a  number  of  veneer  and
plywood plants are given in Table 13.

Dryer Washwater

Veneer  dryers  accumulate wood particles.  Volatile hydrocarbons
will also condense on the surface of dryers to  form  an  organic
deposit  called  "pitch."  In order to avoid excessive buildup of
these substances, dryers  must  be  cleaned  periodically.   Wood
particles  can  be  removed  either  by flushing with water or by
blowing with air.  While some of the pitch can  be  scraped  off,
generally a high pH detergent must be applied to dissolve most of
the pitch and then it must be rinsed off with water.
                              71

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ro
                                                 TA-BLE 12




                                CHARACTERISTICS  OF STEAM VAT DISCHARGES







                                                  Concentrations
Plant
A
B
C
D
E
F
BOD
470
3,117
2,940
1,499
1,298
476
COD
6,310
4,005
8,670
3,435
3,312
1,668
BS
2^430
. *—
5,080
2,202
2,429
917
SS
2,940
86
370
389
107
.74
TS
5,370
__
5,450
2,591
2,536
991
Turb .
450
__
245
249
30
28
Phenols
0

0

0
0
.69

.57
—
.30
.20
Kjld
-Wv
16.
•-3?>
—
1.
4.
-8
8
5
3

87
?3
T-PO^-P pH
5.70 4.12
14 4.1-6.1
5.38
5,3
.173
1,93
            Note:   All units are in mg/1  except Turbidity, which  is  in  JTU^s  and pH.

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47,034(1)
163,440(s)
163,440(1)
44, 220 (s)
1,634(1)
1 ZtA C]\
WATER
IN
LOGS
i
(50)
•
LOG
CONDITIONING
•
(50)
f
VAPORS
OFF
DRYERS
'
(3)
i
DRYER
WASHING

WAT
I-N
PLYW
<


(3)
ER
DOD
k
(7)
VAPORS
OFF
PRESS
<
i
(7.5)
GLUE
WASHUP
' i
i
(7.5)
GLUE

6,583(1)
454(s)
4,222(1)
4,222(1)

4,222(1)
(1)  -  liquid water
(2)  -  steam
(XX)  - % of moisture  by weight
      based on dry wood
Water in = 485,800
Water out= 485,800
           All  units  in  Kg of water per  Day
                        (Ib.  of water per Day)
FIGURE 15 - WATER BALANCE FOR A PLYWOOD MILL PRODUCING
            9.3 MILLION SQUARE METERS PER YEAR
            ON A 9.53mm BASIS
                       73

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                                  TABLE 13

               CHARACTERISTICS OF HOT WATER STEAM VAT DISCHARGES
                                      Concentrations
Plant
A
B
C
D*
E*
BOD
4,
3,

1.
1,
740
100
326
000
900
COD
14,600
9,080
1,492

4,000
DS
3,950
1,570
1,948

319
SS
2,520
460
72
160
1,462
TS Turb. Phenols Kjld-N T-PO.-P pH
6
2
2
1
1
.470 -- 0.40 26.4
,030 -- -- 23.4
,020 800 <1.0 16.? < !.0
,000
,781
5.
3.
6.
4.
4.
4
8
9
5
4
Note:  All units are in mg/1 except Turbidity, which is in JTU, and pH

*Analyses for plants 'D' and 'E' were provided by the respective plants  and
 figures for plant 'E' represent an average for several mills owned by one company

-------
The nature of the dryer wash water varies according to the amount
of  water  used,  the  amount of scraping prior to application of
water, condition of the dryer, operation of the  dryer,  and,  to
some extent, the species of wood that is being dried.

The  amount  of  water  used  varies from plant to plant and from
operator to operator.  One drying operation was observed  to  use
about 23,000 1  (6,000 gal) of water per dryer over a period of 80
hours.   At  this  plant  there were six dryers which were washed
every three weeks.  The washing operation consisted  of  removing
the  bulk  of  the  wood  residue  by blowing it out with air and
hauling it away, and then washing the dryer with water for  about
three-quarters  of  an hour to remove more wood particles.  After
this water cleaning, caustic detergent was applied.  Finally, the
detergent was rinsed off  with  water  for  another  45  minutes.
Samples  of  spent  watfjr  w$re, tajcen during both applications of
water, and the analyses of these samples are shown in  Table  14.
The  effluent  from this washing operation was averaged over a 7-
day period and expressed on a unit of production basis  as  shown
in Table 15.

Various  industry  contacts emphasized that pitch build-up can be
minimized by proper maintenance of the dryers.  Jn addition,  the
volume  of  water  necessary  to  wasji  the dryers can be greatly
reduced.  One Oregon plant of about one-half the size of the  one
described  previously  was observed to use 1/12 as much water per
week to clean its dryers.  Waste water characteristics from  this
plant  are  also  given  in  Tables 14 and 15.  It must be noted,
however, that this plant provides settling and screening for  the
spent  wash water before discharge, and samples were taken at the
point of discharge.

Most dryers are equipped with deluge systems to extinguish  fires
that  might  be  started  inside  the dryer.  Fires in dryers are
quite common, especially in those  that  are  poorly  maintained.
This water is usually handled in a manner similar to the handling
of  dryer  wash water, and many plants actually take advantage of
fires  to  clean  the  dryers.   Fire  deluge   water   can   add
significantly to the waste water problems in some cases.

In  addition  to  the  two waste water sources from veneer dryers
that have been mentioned, water is occasionally used for flooding
the bottom of the dryers.   Many  operators  question  the  logic
behind this practice, while some claim that it prevents fires and
reduces  air  pollution  problems.  In any event, this water does
not have to add to the waste water problems of a  mill.   Several
plants  recycle  all flood, wash, and fire water, and because the
flooding results  in  substantial  evaporation  of  water,  these
plants  have  found  that  fresh  water  can be used to clean the
dryers and still keep the system closed.
                              75

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en
                                                 TABLE 14

                                       ANALYSIS  OF DRYER WASHWATER
Plant
A
Part I
Part B
B
BOD COD DS SS TS Turb .

210 1,131 643 113 756 19
840 6,703 1,095 5,372 6,467 50
60 1,586 1,346 80 1,426 6
Phenols Color Kjld-N T-P04-P

1.31 32 17.7 1.93
0.20 43 211 11.0
4.68 51 2.91 0.495
                      Note:  All units are  concentrations in mg/1 except  for  Turbidity in
                             JTU's and Color  in  Pt-Cob'alt Units.

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Plant
BOB
              TABLE 15




   WASTE LOADS  FROM VENEER DRYERS




COD     DS.      SS      TS    Phenols
Kjld-N
    Note;  All  units are in kilograms  per million square  meters.
T-P04-P
A
B
60.94
2.33
412
60.6
99.7
52.3
319
3.09
418
55.2
0.018
0.014
13.2
0.112
0.18
0.019

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Glue System

Presently there are three types of glues in use in the veneer and
plywood industry;   (1)  phenolic  formaldehyde  resin,   (2)  urea
formaldehyde,  and   (3)  protein  glue.  Protein glues are slowly
being phased out  of  the  industry,  while  phenolic  glues  are
becoming more widely used.  The main source of waste water from a
glue  system  results  from the washing of the glue spreaders and
mixing tanks.  TabjLe 16 shows a list of the  typical  ingredients
of  the  3 categories of glues already established.  The specific
quantities of these ingredients  may  vary  slightly.   Table  17
lists the results of chemical analyses of typical mixtures of the
different  glues.   The  waste waters from the washing operations
are diluted at a ratio of about 20:1  with  water  to  yield  the
concentrations  shown in Table 18-B.  Samples of two phenolic and
one urea formaldehyde waste water were collected and are shown in
Table 17.  These are in the same range as those in Table   18,  so
it  is  reasonable  to  assume  a 20:1 dilution with water.  This
ratio varies considerably, however,  according  to  frequency  of
cleaning and amount of water used.

Waste waters from glue systems are presently being handle^ by  (1)
direct  discharge,   (2) lagooning and discharge,  (3) evaporators,
(4) partial incineration, and  (5) reusing the wash water.

Several studies have been made of waste water flow and  reuse  in
gluing  operations to determine the possibility of complete waste
water recycling.  Most plywood mills add about 20  percent  water
by  weight,  and  the  use of some wash water in the glue mix is,
therefore, possible.  Table 20 shows a list of  southern  plywood
mills  along  with the waste water generated and the water needed
in glue makeup.  Table  21  shows  measurement  of  waste  waters
generated by four Oregon plywood plants.  It is obvious from this
data that in order to use all of the wash water as glue makeup, a
significant  reduction  must be made in the wash water generated.
These reductions, however, are feasible and many plants currently
operate with complete recycle.

Cooling Requirements

A typical combined veneer and plywood  mill  requires  a   certain
amount of cooling water to dissipate heat from the air compressor
as well as from from machines such as the press and the lathe.  A
mill  producing  9.3  million  sq  m/yr  (100 million sq ft/yr) of
plywood on a 9.53 mm  (3/8 in)  basis  needs  to  dissipate  about
55,000  kcal/hr   (217,000  BTU)  from  the compressor and  101,000
kcal/hr (400,000 BTU) from the rest of the plant, for a total  of
156,000 kcal/hr  (617,000 BTU).
                              78

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                        TABLE  16

INGREDIENTS, OF TYPICAL  PROTEIN,  PHENOLIC AND UREA GLUE MIXES


         Protein Glue  for  Interior Grade Plywood:

                       Water
                     Dried  Blood
                     Soya  FLour
                        Lime
                   Sodium Silicate
                     Caustic  Soda
            Formaldehyde Doner for Thickening


        Phenolic Glue  for  Exterior Grade Plywood

                       Water
                     Furafil
                    Wheat Flour
              Phenolic Formaldehyde Resin
                    Caustic Soda
                     Soda Ash


              Urea  Glue for Hardwood Plywood

                        Water
                       Defearner
                Extender (Wheat  Flour)
                Urea Formaldehyde Resin
                                79

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00
o
                                                       TABLE  17



                                      AVERAGE  CHEMICAL ANALYSIS  OF PLYWOOD GLUE
Analysis
and Units
GOD,
mg/kg
BOD,
mg/kg
TOG,
tag /kg
Total Phosphate,
mg/kg as P
Total Kjeldahl Nitrogen,
mg/kg as N
Suspended Solids ,
mg/kg
Dissolved Solids ,
mg/kg
Total Solids ,
mg/kg
Total Volatile
Suspended Solids, mg/kg
Total Volatile
Phenolic
Glue
653,000

/ __

176,000

120

1,200

92,000

305,000

397,000

84,000

172,000
Protein
Glue
177,000

88,000

52,000

2*0

12,00*0

59 ,OQO

118,000

177,030 ,

34,000

137,000
Urea
Glue
421,000

195,000

90,000

756

21,300

346,000

304,000

550,000

346,000

550,000
                             Solids,  mg/kg

-------
                         TABLE 18

    AVERAGE CHEMICAL  ANALYSIS OF PLYWOOD  GLUE  WASHWATER
            (ASSUMING  A 20:1 DILUTION WITH WATER)
Analysis
And Units
COD,
mg/kg
BOD,
mg/kg
TOC,
mg/kg
Total Phosphate,
mg/kg, as P
Total Kjeldahl Nitrogen,
mg/kg as N
Phenols ,
mg/kg
Suspended Solids,
mg/kg
Dissolved Solids,
Total Solids,
mg/kg
Total Volatile
Suspended Solids, mg/kg
Total Volatile
Phenolic
Glue
32,650
—
8,800
6.00
60
25.7
15,250
15,250
19,850
4,200
8,600
Protein
Glue
8,850
440
2,600
13
600
90.5
5,900
5,900
8,850
1,700
6,850
Urea
Glue
21,050
9,750
4,500
37.8
1,065

10,200
10,200
27,500
17,300
27,500
Solids, mg/kg

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GO
ro
                                  TABLE  19



                      CHARACTERISTICS OF  GLUE  WASHWATER



                                    (mg/D

Plant     BOD      COD     TS     DS      SS      Kjld-N     T-PO^-P     Phenols    pH





  A     15,900   16,700  7,910  6,850             21.8        2.46         4.16    9.77





  B                      8,880  6,310          1,640         20.2          0.14    5.25





  C         710    5,670  5,890  3,360  2,530                       •              10.8








Note:  Plants A  and C utilize phenolic  glue  and Plant C uses urea glue

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CO
CO
                                                TABLE  20


             AMOUNT OF  ADHESIVE WASHWATER GENERATED  IN SOUTHERN  PINE PLYWOOD  PLANTS


        Plywood Plant
        Production
(million ,sq .
meters/Year)
9 . 53mm basis
2. 7
3.6
4.5
5.4
6.3
7.2
8.1
9.0
Weekly
Adhesive
__. Use (kg)
38,590
51,454
64,316
77,180
90,044
102,906
115,770
128,634
Amount
Glue
Mixers
9,286
9,286
9,286
11,939
23,877
23,877
23,877
23,877
of Washwater
Glue
Hold Tanks
948
1,895
1,895
1,895
1,895
2,843
2,843
2,843
Produced (Liters)
Glue
Spreaders
6,633
13,265
13,265
13,265
19,898
19,898
26,530
26,530
Total
16,866
24,446
24,446
27,099
45,670
45,670
53,250
53,250
Amount of
Adhesive
per week <
7,364
9,820
2,276
14,732
17,188
19,640
22,096
24,552

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                                                TABLE  21




                                   GLUE WASTE DISCHARGE MEASUREMENTS
oo
                                  Average Discharge
Plant
1
2
3
4
Days
Measured
212
49
42
42
for Days
Measured (I/sec)
0
1
1
3
.814
.54
.13
.36
1966 Production
(aq.m- 9. 53mm basis)
9
12
9
6
,000
,150
,000
,300
,000
,000
,000
,000
Number of
Spreaders
4
3
4
2

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Mass water Balance in a Veneer and. Plywood Mill

An account of water gains and losses that occur in a typical mill
is given in this section*

A  combination  veneer and plywood mill with an annual production
of 9.3 million sq m {100 million sq ft) of plywood on a  9.53  mm
(3/8  in)  basis  is  used  as a basis for the development of the
water balance.  Such a mill would be producing plywood equivalent
to 93,980 kg/day  (207,000 Ib/day) or 95 kkg/day  (104 ton/day)  on
a dry wood basis.

Water Inflows

Water  inflows  from  a typical mill include water from the logs,
glue,  and  from  various  freshwater  intakes  that   are   used
throughout  the  process  without the water becoming incorporated
into the wood.

The  moisture  content  of  incoming  logs  varies  according  to
species.   For  the  purpose  of  these  calculations, 50 percent
moisture is assumed.  Water from incoming  logs  is  thus  47,000
kg/day or 500 kg/kkg  (1,000 Ib/ton).  The amount of water that is
applied  to  plywood  glue  is estimated to be 4,200 kg/day or 43
kg/kkg  (86 Ib/ton) of dry plywood.

The freshwater sources of water vary with  operation.   Based  on
data previously given, the following quantities can be estimated;
about  163,000  kg/day   (360,000  Ib/day)  or 1,750 kg/kkg  (3,500
Ib/ton)  of steam  is used in log conditioning; about 1,620  kg/day
(3,570   Ib/day)  or   17*5  kg/kkg  (35  Ib/ton) of water is used to
wash veneer dryers; and about 4,200 kg/day  (9,300 Ib/day)  or  45
kg/kkg  (90 Ib/ton) of water is used to wash the glue system.

Water Outflows

Water  outflows  from  a  typical  mill  include the water in the
finished plywood, vapor losses from  pressing,  and  spent  water
from log conditioning and washing Operations.

The  amount  of   water  that  is  in   the finished plywood can be
calculated to be  6,600 kg/day  (14,500  lb/  day  or  140  Ib/ton)
based on a 7 percent moisture content.

Vapor  losses  occur  in the dryers and in the press.  Based on  3
percent  moisture  content in dried  veneer,  approximately  44,000
kg/day   (97,400 Ib/day or 940 lb/ ton) of steam must be released.
Similar  calculations indicate a steam  discharge  of  450  kg/day
(1,000   Ib/day  or  10  Ib/ton)  from  the  press.   Waste  water
discharged from log  conditioning  equals  the  amount  of  steam
applied,  if  coils  are not used.  This would be equivalent to  a
discharge of  163,000  kg/day  (360,000 Ib/day or 3,500 Ib/ton).
                              85

-------
Waste water discharges from the washing operations are  equal  to
the  respective  water  usage.  Dryer wash water is approximately
1,635 kg/day  (3,600 Ib/day or 35 lb/ ton), and glue wash water is
approximately 4,200 kg/day (9,300 Ib/day or 90 Ib/ton).
HARDBOARD - DRY PROCESS

Specific Water Uses In A Typical Mill

There are several processes in the dry process hardboard industry
where water might be used.  However, due to a wide variety of raw
material  handling   techniques   and   inplant   processes   and
housekeeping practices, no single dry process hardboard mill uses
water in all of the following processes:

          (1) Log Washing
          (2) Chip Washing
          (3) Resin System
          (U) Caul Washing
          (5) Housekeeping
          (6) Humidif ication
          (7) Fire Fighting

The  quantity of water utilized in any dry process hardboard mill
depends upon water uses in raw  materials  handling  and  inplant
processes,  the  recycle system utilized, housekeeping practices,
and many other factors.  Table 22 shows waste water flows from 11
dry process hardboard  mills.   The  quantity  of  process  water
utilized  in  a  typical mill would be approximately 18,900 I/day
(5,000 gal/day).  This water is either evaporated in the press or
becomes a part of the final product.  A typical waste water  flow
from  a  dry  process  mill  should be less than 1,900 I/day  (500
gal/day).  Cooling water usage varies widely from  mill  to  mill
but  rarely  exceeds  280,000 I/day  (975,000 gal/day).  The water
usage in a dry process hardboard mill  is  low  and  waste  water
discharges are minimal.

Log Washing

Log  washing  is  practiced by a minority of mills and not neces-
sarily on a continuous basis.  Log washing is used to remove dirt
and sand from the log surface, the total amount of  dirt  varying
according   to   harvesting   and  storage  techniques.   Weather
conditions are a factor in the need for log washing as  wet  con-
ditions  may  cause  excessive quantities of mud to adhere to the
logs when harvested.  Mills may store both whole logs  and  chips
on-site  and  the  ratio of logs purchased as compared with chips
vary; the quantity of water utilized will vary accordingly.  Both
fresh water and cooling water from the inplant processes  may  be
used  for  log washing.  Quantities of water used for log washing
can be expected to range from 400 1/kkg  (105  gal/ton)  to  1,250
                              86

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CO
•-J
                                                             TABLE 22
                                                        DRY PROCESS HARDBOARD
                                                    WASTEWATER FLOW AND  SOURCE
Mill
A
B
C
D**
E
F
G
H
I
J*A
K
Log
Wash
0
0
0
YES
81,650
0
0
0
0
0
0
Chip
Wash
0
0
0
0
0
0
0
0
0
0
0
Resin*
Wash
0
0
38
0
0
0
5,670
3
0
570
0
Caul*
Wash
0
570
110
300
0
380
0
750
0
0
0
House-
. keeping*
20,000
380
0
YES
-
0
0
0
0
0
-
Cooling
Water
320,000
81,650
227,000
YES
YES
-
189,000
125,000
160,650
283,500
0+
Humidifi-
cation
0
11,340
0
0
0
0
0
0
0
0
0
                                           Note:  All  flows  given in  liters  per day
                                                * Actual  Intermittant  Flow Averaged Daily
                                               ** Total Waste Contained  on Site
                                                + Cooling Water Used  For  Boiler Makeup

-------
1/kkg  (330  gal/ton).  Typical chemical analyses would include a
BOD of 200 mg/1 and suspended solids of 500 mg/1.

Chip Washing

The purpose of chip washing is similar to that of  washing  logs.
Chips  that  are brought in from outside sources can contain dirt
and sand which can result  in  excessive  equipment  wear.   Chip
washing  serves not only to remove this unwanted matter, but also
gives the chips a more uniform moisture content and, in  northern
climates,  helps  thaw  frozen  chips.   No dry process hardboard
mills reported the use of chip washing, but the trend  is  toward
mills  having  to  wash  chips.  As prime sources of fiber become
increasingly  scarce,  the  trend  will  be  toward  whole   tree
utilization.   This  means  that  whole  trees, or just limbs and
branches, might be chipped in the forest and shipped to the mill.
Because to the increased extraneous material, chip  washing  will
become a necessity.

Fresh  water  may  be used for chip washing or cooling water from
inplant equipment might also be used.  Because there are, at  the
most,  only  one  known chip washing systems in use, there are no
reliable water usage figures or waste  characteristics  available
in the dry process hardboard industry.

Resin System

Water  is  used  to make up the resins which are added as binders
for hardboard.  The water used for making resin becomes  part  of
the  hardboard  and  it  is  evaporated in the press.  Some mills
claim it is necessary to clean the resin  system,  and  available
data,  as  shown in Table 22, indicates that there is no standard
procedure for cleanup as water usage varies widely.

There are two types of resins used  in  the  hardboard  industry,
phenol  formaldehyde  and  urea  formaldehyde.   These resins are
essentially the same as those utilized in  the  plywood  industry
where  many  mills have already gone to a completely closed resin
system.  Table 23 shows  typical  chemical  analysis  of  plywood
glue,

The   chemical   analysis   of  resin  washwater  will  be  those
concentrations shown in Table 23 diluted by  a  factor  depending
upon  the  quantity of water used for wash-up.  Several hardboard
mills presently recycle this wash water as resin make-up water or
simply do not wash at all, therefore having no discharge.

Caul and Press Plate Wash Water

Another minor water usage and waste water source in some mills is
caul and press plate wash water.  After a period  of  use,  cauls
and press plates acquire a buildup of resin and organics on their
surfaces.   This results in sticking in the presses and blemishes
on the hardboard surface.  The cauls or press plates must then be
                              88

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                TABLE 23




AVERAGE  CHEMICAL ANALYSIS OF PLYWOOD RESIN
Analysis and Units
COD, rag/kg
BOD, mg/kg
TOC, mg/kg
Total Phosphate, mg/kg as P
Total Kjeldahl Nitrogen, mg/kg as N
Phenols, mg/kg
Suspended Solids, mg/kg
Dissolved Solids, mg/kg
Total Solids , mg/kg
Total Volatile Suspended Solids, mg/kg
Total Volatile Solids, mg/kg
Phenolic Resin
653,000
—
176,000
120
1,200
514,000
92,000
305,000
397,000
84,000
172,000
Urea Resin
421,000
195,000
90,000
756
21,300

246,000
204,000
550,000
346,000
550,000

-------
cleaned to remove this buildup.  The cleaning operation  consists
of  submerging  the  cauls  in  a caustic cleaning solution for a
period of time to loosen the organic matter*   Press  plates  may
also  be cleaned with a caustic solution inpiace.  After soaking,
cauls are removed, rinsed with fresh water, and then put back  in
use.  The tanks used for soaking the cauls are emptied as needed,
normally only a few times each year.  The soaking water and rinse
water  used  in  a typical dry process hardboard mill ranges from
380 to 950 I/day  (100 to 250 gal/day) or  approximately  4  1/Jtkg
(1.0 gal/ton) of hardboard production.

Miscellaneous Housekeeping Hater

Water  may  be used in small quantities for various cleaning pro-
cedures.  The frequency and quantity of water used  for  cleaning
purposes  is  highly variable as there are generally no scheduled
cleanup procedures.  Information gathered from several  dry  pro-
cess  hardboard  mills indicates that this water usage can be ex-
pected to range from zero to less than 1,500 I/day  (400  gal/day)
in  a typical mill.  This source of waste water results in such a
minor volume that it can easily be disposed of on-site.   Several
mills  utilize no water at all for cleaning as all of their house
cleaning is done by sweeping and vacuum cleaning.

Humidification

All dry process hardboard mills humidify  board  after  pressing.
This  procedure  consists   of  passing the boards through a room
with a high  humidity  and  temperature  to  bring  the  moisture
content  to  an  air dry level.  Most mills report no waste water
discharge from this operation.

Fire Water

A. major problem with the dry process for manufacturing  hardboard
is  the  fire hazard.  The inside of a dry process hardboard mill
may become coated with dry fibers  and  an  electrical  spark  or
excessively  hot  press  or  other  piece of equipment can easily
start a fire.  More frequently a fire starts  in  a  refiner  and
quickly  spreads  through the fiber conveying system.  Mills have
elaborate fire fighting systems which  use  large  quantities  of
water  to  put  fires  out  quickly.   Fires  are  obviously  not
scheduled and their frequency varies  from  mill  to  mill.   The
water  used to control a fire will vary according to the duration
and extent of the fire.

cooling- Water

The largest water usage in a dry process hardboard  mill  is  for
cooling  water.   This  water is used for cooling various inplant
equipment such as refiners and air compressors, and  is  normally
not  changed  in  quality  except  for the addition of heat.  The
volume of cooling water varies widely from mill to mill depending
upon temperature of freshwater source and the equipment within  a
                              90

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mill.   Cooling  water  can  be  expected to range from 18,900 to
280,000 I/day (5,000 to  75,000  gal/day)  with  a  typical  mill
utilizing  190,000  I/day  (50,000  gal/day).   Cooling water may
become contaminated with lubricating oil and in  this  event  the
oil must be removed before the cooling water is discharged.

Scrubber Water

Air  pollution  from  dry process hardboard mills is a major con-
cern.  One method of air pollution control  is  the  use  of  wet
scrubbers.   Although only two hardboard mills report using a wet
scrubber, the future trend appears to be toward the  use  of  wet
scrubbers  in  dry  process hardboard mills.  The water usage for
wet scrubbing in a dry process hardboard mill will vary depending
on the individual scrubber design.  Since there are only two  wet
scrubbers  in  operation, representative data for the industry is
unavailable.  One of the mills using a  wet  scrubber  reportedly
achieves  zero  discharge  by settling and filtering the scrubber
water before recycle.  In fact, there is need for water makeup.


Mass Water Balance In A Dry Process Hardboard Mill

For the purpose of illustrating the water requirements in  a  dry
process hardboard manufacturing plant, presented below is a water
balance.   This  presentation is not intended to suggest that the
average  (or typical) plant in the industry produces 225  kkg/day.
The  water intakes and outflows are presented also on a volume of
water per unit of production basis, also, to illustrate the water
requirements and outflows related to the operations  involved  in
the manufacture of hardboard.
A  schematic  diagram  of  the  water  balance   (net  inflows and
outflows) for a typical dry process hardboard mill  is  shown  in
Figure   16.   Water  gains  or outflows are shown as 1/kkg of dry
product  produced in a typical 225 kkg/day mill.

Water Inflows;  Water inflows in a typical dry process  hardboard
mill  result  from incoming raw materials and fresh water intake.
Incoming wood normally  has  approximately  50  percent  moisture
which represents 100 percent of the final product weight.
Water  from  incoming
 (240 gal/ton)
wood  =  1,000 1/kJtg (50 percent moisture)
The water usage within a dry process  hardboard  mill  is  highly
variable  depending upon water usage within an individual process
and plant practices and procedures.  A typical dry  process  mill
uses  water only for glue preparation, caul wash, humidification,
and cooling.
Water in glue
product  (8.4 gal/ton)
  - 35 1/kkg of (3.5 percent  of  product)
                              91

-------
ro
             6AIN = IOOO
             RAW
             MATERIALS
             HANDLING
COOLING WATER
  GAIN = 1250
                                                  LOSS=460
                                           SYSTEM
                                           GAIN»35
FIBER
PREPARATION
                                    I

                              COOLING WATER
                                 LOSS = I250
FIBER
DRYER
                                    FELTER
                             CAUL WASH
                               GAIN=4.2-»
                                            LOSS = 4.2
                                                                  PRESS
                                                     FRESH WATER
                                                       GAIN*50—*-
                                                   LOSS-75
                                    HUMIDIFICATION
                                                 FINISHING
                                                                  PRODUCT
                                                                    TOTAL  GAIN =23392
                                                                    TOTAL  LOSS =2339,2
                    * GAINS  AND LOSSES SHOWN IN LITERS/TON DRY PRODUCT
                    FIGURE  16  - WATER BALANCE FOR TYPICAL DRY PROCESS HARDBOARD MILL*

-------
Caul   wash   950   1/day
product  (1 gal/ton)

Humidification
product  (12 gal/ton)

Cooling  water-284,0 00
product  (300 gal/ton)

Total Water Inflows
       =  
-------
           LOGS

           O
           LOG
         STORAGE
1
' \/
LOG WASH


•
'
DEBARKER



CHIPPER
/CH
/STO
ER IN
\
RAGE\




*
i
V
/ CH
/ WA
-

i
IP \
SH \
\
    WATER OUT
    o
TO PROCESS
FIGURE 17  - WATER USAGE IN RAW MATERIALS HANDLING
           IN THE HARDBOARD INDUSTRY
                    94

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hardboard discusses raw materials handling, and the  figures  and
discussion  there also apply to the wet process hardboard segment
of the timber products processing industry.


Fiber Preparation

As  previously  discussed,  there   are   two   principal   fiber
preparation  processes:   (1)  thermal  plus  mechanical refining
process and,  (2) the  explosion  process.   Figure  11  showed  a
schematic  diagram  of a typical wet process hardboard mill where
thermal plus mechanical refining is used for  fiber  preparation.
All  but  two  wet  process  mills utilize some variation of this
process.  Two mills utilize the explosion  process  as  shown  in
Figure  18.

The  amount of water used in fiber preparation in the wet process
is relatively small as compared to overall water  use  in  a  wet
process  mill.  In general, the only water used in fiber prepara-
tion is the addition of steam into the cooker.  This quantity  of
steam   is approximately equal to one-half the weight of dry chips
processed or approximately 0.5 cu m/kkg  (120 gal/ton).

The principal  reason  for  significant  waste  water  flows  and
concentrations  from  the  wet  process  as compared with the dry
process is the fact that the fiber is diluted from  approximately
40  percent  consistency  to  1.5  percent  consistency  prior to
forming on a wet felting machine.  There are limitations  on  the
concentrations of organics in the process water.  This means that
most  of the soluble organics released into solution during fiber
preparation must be disposed of in some manner as only a  portion
of the  solubles may be retained in the hardboard.

The interrelation between fiber preparation processes, variations
of  cooking  time,  and  temperature  and wood chemistry on waste
water discharge is extremely important.   Wood  is  difficult  to
define  chemically  because it is a complex heterogeneous product
of nature made up of interrelated  components,  largely  of  high
molecular   weight.    The  principal  components  generally  are
classified as  cellulose,  lignin,  hemicellulose,  and  solvent-
soluble substances  (extractives).  The amounts present are in the
range   of  40  to 50 percent, 15 to 35 percent, 20 to 35 percent,
and 3 to  10  percent,  respectively.   The  yield,  composition,
purity,  and  extent  of degradation of these isolated components
depend  on  the  exact  conditions  of  the  empirical  procedures
employed   for  their  isolation.   Variations  in  the  chemical
composition of  wood  influences  the  quantities  and  kinds  of
chemicals released during fiber preparation.

At  normal temperatures wood resists degradation by chemicals and
solvents.  This may be attributed to the interpenetrating network
structure of wood comprised of  polymers  with  widely  differing
properties.   Also,  the  high  crystallinity of the carbohydrate
                              95

-------
                                                                          TO ATMOSPHERE
CHIP:
       WATER  IN


       WATER  OUT
                                                         MAKE-UP
                                                         WATER
                                                                                      TO
                                                                                    FINISHING
                    FIGURE 18  -  WATER USE  IN THE EXPLOSION PROCESS

-------
system reduces  the  accessibility  of  the  wood  components  to
reagents.

Water at room temperature has little chemical effect on wood, but
as  temperature  rises  and pH decreases because of the splitting
off  of  acetyl  groups,  wood  becomes  subject  to  rapid  acid
hydrolysis with the dissolution of carbohydrate material and some
lignin.   At  temperatures  above  140°C,  considerable and rapid
removal of hemicelluloses,occurs.  Cellulose  resists  hydrolysis
better than the hemicellulose fractions.

The  thermal  and  explosion  pulping  processes  make use of the
effect of water on wood at high temperatures to prepare fiber for
mechanical refining prior to being formed  into  hardboard.   The
high  temperatures  soften  the  lignin-hemicellulose  matrix  to
permit the separation of fibers with reduced power cost and fiber
damage.  Also, carbohydrate and lignin degradation products,  and
the  lignin  softened by high temperature^, facilitate bonding of
the fibrous structure upon drying of the board.

Cooking wood with steam at temperatures of about 180°C  causes  a
rapid  loss  in  weight.   Part  of  the  'loss  is due to thermal
decomposition and simple solution, but the acids released by  the
wood  hydrolyze appreciable amounts of carbohydrates as well.  In
commercial operations, yields of pulp fall to between 75  and  90
percent,  and  therefore  potential waste water problems increase
significantly.

In the explosion process wood chips are exposed to  high-pressure
steam  in  a  "gun" or small digester fitted with a quick~opening
valve that allows the chips to disintegrate when the pressure  is
abruptly  released.  In the gun the chips are steamed at 41.8 atm
 (600 psi) for 1 minute, and the pressure is then increased to  69
atm   (1,000  psi) for an additional 5 seconds before the valve is
opened.  Differences in wood  species,^ condition,  and  size  of
chips  modify  the  cycle.   The  high temperature, high pressure
treatment does not remove the lignin but  makes  it  sufficiently
plastic  for  the chips to burst apart on release.  Hemicellulose
is hydrplyzed,  becoming  pentose  sugars.   Some  of  these  are
dehydrated and polymerized to form furfural resins as a result of
the  steaming  and  the  subsequent high temperature pressing and
tempering involved in manufacturing boards.  This process  causes
the  release  of significant quantities of organics which must be
disposed of as a waste stream.

Another representative and more common process  makes  use  of  a
screw  press  to  force  compressed  chips  into  one  end  of  a
horizontal stainless-steel tube, typically 3m  (10 ft)  long  and
one  m   (3  ft) in diameter, which the chips traverse in about 30
seconds while exposed to steam at 182°C and 12.9 atm   (175  psi).
At  the far end they are fiberized in a single-rotating disk mill
while still hot and under pressure.  From the disc mill the  pulp
is  discharged  to  a  cyclone, from which it goes to a surge bin
followed by a second refiner for further processing.  Other types
                               97

-------
of continuous or quick-cycle digesters  may  be  substituted  and
give  similar  results.   Because  of  the lower temperatures and
pressures, the quantity of released organics is considerably less
than in the explosion  process,  resulting  in  potentially  less
waste.

The  yield,  chemical composition, and physical properties of the
pulps prepared by any method  are  dependent  upon  two  sets  of
variables:

Variables associated with the wood:

                  1.  Species
                  2.  Density
                  3.  Growth factors
                  4.  Moisture content
                  5.  Length of storage
                  6.  Particle size

Variables associated with the fiber preparation system:

                  1.  pH of liquor  (water solution)
                  2,  Temperature and pressure of digestion
                  3.  Time of digestion
                  4,  Method of defibration

The  dissolution of the wood substances takes place mainly during
pre-heating and defibration process and is closely related to the
kind of raw material used.

It is difficult to make determinations of the yield of pulp  from
wood  as a function of the pre-heating conditions,  some attempts
have been made, however, and in Figure 19 a graph  for  beechwood
is shown, where the preheating period was extended to 16 minutes,
These  determinations  were  made with water as "cooking liquor,"
and it is clearly shown that the dissolution proceeds much faster
as the pre-heating temperature is increased.

During the pre-heating two primary reactions take place.  One  is
the   hydrolysis   of   hemicellulose   molecules,  whereby  oli-
gosaccharides are formed.  These short-chain molecules are  small
enough  to dissolve in water.  The other reaction is the hydroly-
sis of acetyl groups, whereby acetic acid is formed,  causing  an
increase  in  the hydrogen ion concentration in the raw material.
The higher acidity causes the  hydrolytic  reactions  to  proceed
still   faster.    Thus   the   reactions   can  be  said  to  be
autocatalytic.  For that reason it is very difficult to calculate
rates of reaction for the dissolution cf wood  substances  during
the  pre-heating  stage.   The  rate of reaction seems to roughly
double with an increase in temperature of about 8°c (14°F), which
is normal for most chemical  reactions.   So  far  no  exhaustive
investigations  seem  to have been made on the composition of the
substances  dissolved  during  the  pre-heating  and  defibration
steps.   An  examination  of  the  composition  of the substances
                              98

-------
      YIELD  %
100
 90
 80
                                    I58°C
                                   I72°C
                                    I83°C
 70
              5         10
              PREHEATING   TIME
             15        20
             MINUTES
      FIGURE  19
-  EFFECT OF PREHEATING TIME AND
  TEMPERATURE ON YIELD
                        99

-------
dissolved in the thermal-mechanical process was made  by  Edhborg
in  1958.   The  temperature in the Asplund-Defibrator process is
normally about 180°C and the pre-heating time is usually from one
up to a few minutes.  The temperature in the  explosion  process,
on the other hand, is increased to between 250 and 30Q°C, even if
it  is  only  for a few seconds.  This leads to larger amounts of
substances being dissolved in the latter process and also to more
acidic conditions—a pH value of  about  3  was  obtained  in  an
extract  from an explosion pulp whereas the pH values in extracts
from defibrator pulps'" are  usually  close  to  4.   The  acidity
depends  partly on volatile acids like acetic and formic acid and
partly on non-volatile ones, among which uronic acid is the  most
frequent.  ;

The  investigation  on  dissolved  substances  in  the  explosion
process was based  on  coniferous  wood  as  raw  material.   The
dissolved  substances  in this case consisted of about 70 percent
carbohydrates, 10 percent lignin (partly modified) and 20 percent
"organic resins."  The  carbohydrates  consisted  of  35  percent
pentosans (mostly xylans)  and 65 percent hexosans.

Corresponding  investigations  on  dissolved  substances  in  the
Asplund-Defibrator process were made with beech as raw  material.
In  this  case  75  percent  of  the  dissolved  substances  were
carbohydrates and a few percent were lignin type substances.   In
addition,  about  10  percent acetic acid, partly free and partly
bound as acetyl groups,  were  found.   In  this  case  about  80
percent  of  the carbohydrates were pentosans (mainly xylans) and
20 percent hexosans.

Tables 24 and 25 relate properties and composition of many common
woods used in this country, and Figure 20 indicates  the  effects
various treatments have on these components.  Figure 21 depicts a
general relationship of lignin dissolution versus percent of wood
dissolved.

Mat Formation and Pressing

Figure 11 shows that from the refiner, fiber is discharged into a
cyclone where the fiber is diluted with process water.  Figure 22
shows  a  typical  schematic diagram of the process water flow in
the  wet  process.   From  the  refiner,  fiber  is  diluted   to
approximately  5.0 percent through the cyclone then diluted still
further to approximately 1.5 percent fiber in the stock chest.

A mat is then formed on the wet forming machine where  the  fiber
concentration  is,  increased to approximately 35 percent prior to
wet pressing.  Water removed from the mat formation  flows  to  a
process water chest where it is recycled as process water.  Water
released  upon  pressing  either  evaporates to the atmosphere or
flows back to the process water chest or is  discharged  directly
as  a  waste  water.   Process  water  may  be recycled until the
temperature,  or  the  concentration  of  soluble   organics   or
suspended  solids becomes too high.  Normally, fresh makeup water
                              100

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1
TOTAL
WOOD
SUBSTANCE

Neutral
Solvents
and/or
Steam
Soluble
or
Volatile

3
EXTRACTIVES
5%

2
EXTRACTIVE
FREE WOOD
95%

f
INORGANIC
<.05%
Mild
Oxidation
and
Extraction
i
Degraded
Soluble
4
SOLOCELLULOSE
(TOTAL
POLYSACCHARIDE
FRACTION) .
70%

5
LIGNIN
25%


6
Dilute WOOD
Aqueous "" CELLULOSE
Alkali 60o/o
.
Ac
Soluble Hydrc

'
GLUCOS
TRACES
OTHER
CARBOH1
AND IMP
id
)lysis
E +
OF
fDRATES
URITIES
MANNOSE
XYLOSE
GALACTOSE
ARABINOSE
URONIC  ACIDS
    Acid
  Hydrolysis
HEM1CELLULOSE
     20%
          FIGURE 20
- THE CHEMICAL COMPONENTS OF WOOD

-------
o
-to
                                                    TABLE 25

                                     ANALYSES OF SOME COMMON SPECIES OF WOOJ)
                                   (Extractive-free basis,  percent of dry wood)
Constituent
Ash
Acetyl
Lignin

a-Cellulose
Heoiicsllulaee
Total (a " ". '

a-Cellulose (b
Mannac (c
Xylan
Uronic anhydride
CH (d
Total (a
Douglas
fir
0.3
0.6
2fi.4

57,2
14,1
100,6

48.3
5.4
6.2
2.8
0.0
92.0
Loblolly
pine
0.3
1.1
29.5
Summation A
55.0
15.3
101.2
Summation B
46.6
4.7
10.1
3.8
0.2
96.3
Black . Southern
spruce red oak
0.4
1.1
28. -Q

51.5
17.4,, ,
98.4

45. ft ...
8.0'
10.5
4,1
0.2
97.9
0.2
3.3
25.2

45.7
23.3
97.7

43.7
_~
20.0
4.5
0.6
97.5
                a)  Including ash,  acetyl,  and lignin.
                b)  Corrected for  mannan,  xylan,  and uronic anhydride.
                c)  By the phenylhydrazine method;  the  figures are probably low.
                d)  Calculated from methoxyl not  in lignin.

-------
o
(Jl
           CHIPS
                     STEAM
         1
                           (40)
                 SCREW

                 FEED
(XX)



, 	 \ I 	 j CY L— ' STOCK L-1 WET FORMING
.REFINER , 	 : CL nCHES'IS
j 1 1 0 1 I 	 . 	
r—3 l — i k N. ;(5) A (u
\ /

DILUTION
WATER

MAKE-UP
WATER
MACHINE
J) 1
PROCESS
WATER

CHEST
t !
A





(35)
<*"
*S4-~
S / / s / / /

TO
A ATMOSPHERE
WET I— rA
PRESS I""1"/
1 TO
1
/
/
/
/
>
*
/
/
s
/
/
/
/
>
<
FINISHING
r ^
/SS//////J>
V"
TO
TREATMENT
                    WATER  IN






                    WATER OUT






                    ALTERNATE ROUTE
                    APPROXIMATE  PERCENT FI8*R

                    (CONSISTENCY IN  PROCESS)
                  FIGURE  22  -  PROCESS WATER RECYCLE IN A TYPICAL WET PROCESS HARDBOARD MILL

-------
is added at a constant rate to control these parameters  and  the
overflow is discharged to waste.

In  the  explosion process considerably more soluble organics are
released.  Two plants use process water for fiber washing.  Fiber
wash water from the  explosion  process  is  a  major  source  of
pollutants.   A  waste  load from this process alone of 40 kg/kkg
(80 Ib/ton) into a flow of 2.5 cu  m/kkg  (600  gal/ton)   is  re-
ported.   Typical  waste  water concentrations of this fiber wash
are:

                  BOD * 22,620 mg/1
                  COD = 51,100 mg/1
                  TSS = 32,000 mg/1
               Volume =* 2.5 cu m/kkg  (600 gal/ton)

Because of these high waste concentrations it has been found that
it is practical to evaporate this waste stream.  The concentrated
liquor is sold as cattle feed or incinerated  (Figure  23).   This
is  the  normal  procedure  in  the  plants that use an explosion
process.

Two other wet process  mills  which  use  the  thermal-mechanical
cooking  process  wash fiber prior to mat formation.  These mills
do not evaporate this washwater separately  as  is  done  by  the
explosion process mills, but discharge it directly to waste.


The   moisture   in   the  chips  entering  the  wet  process  is
approximately 50 percent.  Assuming that the mat is formed from a
1.5 percent fiber concentration, that the board coming  from  the
press  has a zero percent moisture, and that there is no recycle,
approximately 66.8 cu m/kkg  (16,000  gal/ton)  of  process  water
must  be disposed of in some form.  While a portion of this water
will be disposed of as steam, the majority will be discharged  as
a  waste  stream.   The actual volume discharged is a function of
the amount of  recycle  practiced.   There  are  three  principal
factors  which  limit  recycling  of  process water: temperature,
suspended solids, and soluble solids.

Usually a process water  temperature  of  a  certain  minimum  is
required  to avoid excessive use of resin.  At lower temperatures
the naturally occurring resins in the  fiber  will  set,  thereby
becoming ineffective for bonding.  Furthermore, when the board is
formed  at  low  temperature,  longer pressing times are required
which can significantly reduce production rates.  Most  hardboard
mills  operate  with  a  process  water  temperature between 30°c
(86°F) and 63°C  (145°F).  The more the process system is  closed,
the  higher  its  temperature becomes.  It has been found that as
temperatures   increase,   certain   corrosion    problems    are
experienced.    Machines   become   very  humid,  making  working
conditions unpleasant.  A critical  temperature  seems  to  exist
after  which spots will appear on the board, thereby lowering the
                              106

-------
                                                                                       TO ATMOSPHERE
O
--J
              CHIPS
                    u  n
                    GUN
                    Vv
)±3 C=T
f 1





WASHEf
\





?













J CHEST | [MACH
Ljf


. 	 	
1 " pRncpss
WATER
CHEST
                      WATER IN
WATER OUT


CONCENTRATED

BY-PRODUCT
                                              CONCENTRATE TO

                                              CATTLE FEED
                                                                COMPENSATE
                                                                            TO
                                                                            FINISHING
                                                                                TO TREATMENT
                                FIGURE  23  -  PROCESS  WATER RECYCLE IN A HARDBOARD MILL

                                             USING THE  EXPLOSION  PROCESS

-------
aesthetic quality of the board.  This critical temperature varies
with raw material, process and product produced.

Increased recycling of process water increases the  concentration
of  soluble  organics.   This  increased concentration raises the
risk of spot formation on the board and the chance of sticking in
the press.   This  is  partly  due  to  build-up  of  volatilized
organics  on press plates.  The critical concentration of soluble
organics, above which process problems are encountered,  is  rel-
ated  to  concentration  and  type  of  soluble  materials in the
process water.

The effect of suspended  solids  concentrations  relates  to  the
dewatering  characteristics  of  the  board.  As suspended solids
concentrations increase with recycling, a  certain  concentration
is  reached  after  which the board will not exhibit proper water
drainage during mat formation.   This  can  be  attributed  to  a
buildup  of  fines which cause the mat to dewater slowly.  As the
suspended solids level becomes too high in the process water they
must be removed either by blowing down  this  concentrated  water
and  diluting it with fresh water, or by removing the solids from
the process water by some other means.


Miscellaneous Waste Water Sources

By far the major  waste  water  discharges  from  a  wet  process
hardboard  mill  are  process water from mat formation, pressing,
and fiber washing.   Other  waste  water  sources  which  may  be
classified  as  miscellaneous  streams  include resin system wash
water, caul wash water, housekeeping water, and cooling water.  A
discussion of these sources can be found in the earlier  part  of
this section relating to dry process hardboard.


Total Waste water Flow

Table  26  is  a summary of the total waste water flow from seven
wet process hardboard mills.  Table 27 gives  a  summary  of  the
average waste water concentrations from these same mills.

Waste  water flows vary from about 4.6 to 45.9 cu m/kkg  (1,000 to
11,000 gal/ton), BOD concentrations vary from 700 mg/1  to  4,000
mg/1  and  suspended solids from 220 to 1,650 mg/1.  A comparison
of data reported as raw waste water concentrations from  mill  to
mill should be made with caution-  Several mills report raw waste
water  concentrations after primary sedimentation while others do
not.  These mills utilize primary clarifiers  as  part  of  their
recycle  systems while other mills consider primary clarifiers as
part of their waste treatment system.  The average  discharge  of
BOD5  in  the  raw waste water ranges from 28 to 50 fcg/kfcg  (56 to
100 Ib/ton), while average discharge of suspended  solids  ranges
from 3.2 to 19 kg/kkg  (6,4 to 38 Ib/ton).
                              108

-------
                    TABLE 26

WASTEWATER DISCHARGES FROM WET PROCESS HARDBOARD
Plant
1
2
3
4+
5
6
7
8*
Production
(metric tons)
91
77
1,356
136
82
127
356
327
Wastewater
(cubic meters /day)
4,164
2,952
16,578
1,590
757
908
1,628
833
Wastewater
(cubic meters/kke
45.9
38.2
12.2
11.7
9.3
7.1
4.6
2.6
      + Chip Wash Included
      * Projected Figures
                109

-------
                               TABLE 27

     RAW WASTEWATER CHARACTERISTICS FROM WET PROCESS HARDBOARD
Discharge Flow
Plant
1
2
3+*
4
5
6*
7*
8
cu m/D eu
4,164
2,945
16,578
1,589
757
897
1,635
840
m/metric t
45.9
38.2
12.2
11.7
9.3
7.1
4.6
2.6
BOD
on mg/1 kg/kkg
720
1,130
.1,800
3,000
3,500
3,900
—
3,350
33
50
23
28
32
28
—
8.5

S.S.
mg/1 kg/kkg pH
220
—
540
1,650
430
450
—
48
10
—
6.5 5.0
19 4.5
4 4.4
3.21 4.0
—
0.125
* After Primary Treatment
+ Masonite Explosion Process

-------
other  representative analyses of raw waste water discharged from
a typical wet process hardboard mill are shown below:

        Parameter             Concentration  (mq/1)

        BOD                     1,300 -  4,000
        COD                     2,600 - 12,000
        Suspended Solids          400 -  1,100
        Total Dissolved Solids    500 -  4,000
        Kjeldahl Nitrogen         017    4.0
        Phosphates, asp           0.3-3.0
        Turbidity                  80 -  700
        Phenols                   0.7 *  1.0

        pH Range                  4.0 -  5.0

Water Balance for a Typical Wet Process Hardboard  Mill  For  the
purpose  of illustrating the water reguirments in a wet hardboard
manufacturing plant, presented below is a  water  balance.   This
presentation  is  not  intended  to  suggest that the average  (or
typical,) plant in the industry produces 127 kkg/day.  The  water
intakes  and outflows are presented also on a volume of water per
unit  of  production  basis,  also,  to  illustrate   the   water
requirement  and  outflows  related to the operations involved  in
the manufacture of hardboard.

A schematic  diagram  of  the  water  balance   (net  inflows  and
outflows)  for a typical mill is shown in Figure  24.  Water gains
or losses are shown as liters of water/kkg of product produced  in
a 127 kkg/day  (140 ton/day) mill.

Water Inflows.  Water inflows in a typical wet process  hardboard
mill  result  from  incoming raw materials and freshwater makeup.
Incoming wood has approximately 50 percent moisture content which
represents 100 percent of the final product weight.

The volume of miscellaneous housekeeping  water,  used  for  such
things  as  floor and caul washing, is highly variable.  There  is
little  data  as  this  stream  is  normally discharged  to  the
treatment system with the process water without monitoring.


Water from incoming chips   = 1,000 1/kkg
 (50 percent moisture)          (240 gal/ton)

Steam to preheater          - 500 1/kkg
                               (120 gal/ton)

Cooling and seal water      = 29,840 1/kkg
                               (7,150 gal/ton)

Additive dilution water     ~ 83.5 1/kkg
                               (20 gal/ton)
                               111

-------
ro
LOSS = 83.5
STEAM GAIN = 83.5 LOSS* 186 GAIN* 50
SJk.iSS'V A WATER FROM TO STEAM OR
COOLING 8 ' f ADDITIONS ATMOSPHERE WATER
GAIN =50O SEAL WATER A 1 1
STEAM II II If JL
II Jl II JL, v
CHIPS i i " I 	 *"^ 	 1 lc I~J STOCK '-'wFT FORMING 	 w*T 	 uiiuininirp '"A
r^l^gPREHEATE^ REFINER , 	 I'ci (] CHESTS p| MACHINE PRESS pV
(50) \ (40)1 	 ' J 	 1 L 0 /(5) A (1.5
NSCREW FEED ^ V.V
GAINS = I,000 Jl "/^ 17,590 46,6
LOSS =29,6 17
COOI ING AND 1

StAL WATER DILUTION
WATER
MAKE-UP 	
WATER
55 V 63,911
PROCESS
WATER c^rr™
CHEST r \
1 !_J
I-TON
1.669 PRODUCT
F LOSS= 11,267
A _ 	
                                                                                  TO TREATMENT
> ALTERNATE ROUTE

  WATER  IN

  WATER  OUT
                                                                 MISCELLANEOUS
                                                                 HOUSEKEEPING
                                                                 GAIN=42
                (XX)   PERCENT FIBER  (CONSISTENCY IN PROCESS)

                ALL NUMBERS* LITERS /METRIC TON
TOTAL GAIN
TOTAL LOSS
41,405
41,405
                       FIGURE  24 - WATER BALANCE FOR A TYPICAL WET-PROCESS HARDBOARD MILL

-------
Process water makeup
Humidifier
Miscellaneous housekeeping  =
Total Water Inflows
9,890 1/kkg
(2,370 gal/ton)

50 1/kkg
(12 gal/ton)

42 1/kkg
(10 gal/ton)	

=41,405 1/kkg of product
(9,922 gal/ton)
Water Outflows:  Water outflows in a wet process mill result
from:
Press Evaporation
Cooling and Seal Water
discharge)

Steam from cyclone
Discharge of excess pro-
cess water  (includes mis-
cellaneous housekeeping
water discharge
Water in product

Total Water Outflows
188 1/kkg
(45 gal/ton)

29,817 1/kkg
 (7,145 gal/ton)

83.5 1/kkg
(20 gal/ton)
11,267 1/kkg
(2,700 gal/ton)

50 1/kkg
(12 gal/ton)
= 41,405 1/kkg of product
(9,922 gal/ton)
WOOD PRESERVING SUBCATEGORIES
Waste water characteristics vary with the particular preservative
used, the volume of stock that is conditioned prior to treatment,
the  conditioning  method used, and the extent to which effluents
from  retorts  are  diluted  with  water  from   other   sources.
Typically,  waste  waters  from  creosote  and  pentachlorophenol
treatments have high phenolic, COD, and oil contents and may have
a turbid appearance that results from emulsified oils.  They  are
always acid in reaction, the pH values usually falling within the
range  of 4,1 to 6.0.  The COD for such wastes frequently exceeds
30,000 mg/1, most of which is attributable to entrained oils  and
to  wood extractives, principally simple sugars, that are removed
from wood during conditioning.
                              113

-------
Closed steam Conditioning

The characteristics of wood preserving waste water are  different
for  plants that practice modified-closed or closed steaming.  In
the former process, steam condensate is allowed to accumulate  in
the  retort  during  the  steaming  operation until it covers the
heating coils.  At that point, direct steaming is stopped and the
remaining steam required for the cycle is  generated  within  the
retort  by  utilizing  the heating coils.  Upon completion of the
steaming cycle, the water in  the  cylinder  is  discarded  after
recovery of oils.  In closed steaming, the water in the retort at
the  end of a steaming cycle is returned to a reservoir after re-
covery of free oils, and is reused instead of being discarded.

The principal advantage of modified-closed steaming/ in  addition
to  reducing  the  volume  of  waste released by a plant, is that
effluents from the retorts are less likely to contain  emulsified
oils  than  when  open  steaming  is used.  Free oils are readily
separated from the waste water; and as a result of the  reduction
of  the oily content, the oxygen demand and the solids content of
the waste  Water  are  reduced  significantly,  relative  to  the
effluent  from  plants  using open steaming.  Typical oil and COD
values from a single plant before and after the  plant  commenced
modified-closed   steaming  are  shown  in  Figures  25  and  26,
respectively.  The COD of the waste water was  reduced  by  about
two-thirds  when this steaming method was initiated.  Oil content
was reduced by a factor of ten.

Water used in closed  steaming  operations  increases  in  oxygen
demand, solids content, and phenol concentration with each reuse.
The high oxygen demand of this waste is attributable primarily to
wood  extracts,  principally  simple sugars, the concentration of
which increases with the reuse of the water.  Because practically
all of the solids content of this  waste  are  dissolved  solids,
only insignificant reductions in oxygen demand and improvement in
color result from primary treatments involving flocculation.  The
progressive  changes in the parameters for water used in a closed
steaming operation are shown in Table 28.  Although  such  wastes
are  perhaps  more  difficult  to  treat,  this  disadvantage  is
counterbalanced in part by the fact that  substantial  reductions
in  the  volume  of  waste  water  and total weight of pollutants
released can be achieved by using closed steaming.

affect of Time

Because  many  plants  use  the  same  preservatives  and  follow
essentially  the  same  treating practices, the waste waters they
release are qualitatively similar with respect  to  a  number  of
chemical  and  biochemical  properties.  Quantitatively, however,
they differ widely from plant to plant, and  even  from  hour  to
hour at the same plant, depending upon the time during a treating
cycle that samples for analysis are collected.
                               114

-------
                Avg. oil content
                 before closed
                 steaming-1360mg/1
                              Avg.oil  content
                                after closed
                                steaming—136 nig/
                    8
       12
TIME ( weeks)
16
20
FIGURE 25 - VARIATION IN OIL CONTENT OF EFFLUENT WITH TIME
            BEFORE AND AFTER INITIATING CLOSED STEAMING

-------
     10
20
30
  40    50
TIME (days)
60
130
FIGURE 26 -  VARIATION  IN  COD  OF EFFLUENT WITH TIME BEFORE AND
            AFTER CLOSED  STEAMING:  DAYS 0-35 OPEN STEAMING;
            DAYS 35-130 CLOSED STEAMING

-------
                      TABLE  28




PROGRESSIVE CHANGES IN SELECTED CHARACTERISTICS OF




  WATER RECYCLED IN CLOSED STEAMING OPERATIONS
Charge
Number
1
2
3
4
5
7
8
12
13
14
20

Phenol
46
169
200
215
231
254
315
208
230
223
323
NOTE:
COD
15,516
22,208
22,412
49,552
54,824
75,856
99,992
129,914
121,367 1
110,541
Total
Solids
10,156
17,956
22,204
37,668
66,284
66,968
67,604
99,276
04,960
92,092
123,429 114,924
Values expressed
as mg/1
Dissolved
Solids
8,176
15,176
20,676
31,832
37,048
40,424
41,608
91,848
101,676
91,028
88,796

                        117

-------
CO
                                          8         12        16
                                               TIME  ( hours)
24
                 FIGURE 27 -  VARIATION IN COD CONTENT AND WASTEWATER FLOW RATE WITH TIME

-------
Data on the effect of time of sampling during a treating cycle on
the  flow rate ancl COD content of effluent from a plant operating
a single retort are shown in Figure 27.  Flow rate  was  measured
and samples for analysis collected at 30 minute intervals, begin-
ning  during a steaming cycle and continuing through the treating
cycle and part of the succeeding steaming cycle.  The COD of  the
effluent varied inversely with flow rate and ranged from 400 mg/1
to  43,000  mg/1  during  the 24 hour sampling period, a 100-fold
variation.  Plow rate varied from 7570  1/day  to  151,400  I/day
 (2,000  gal/day to 40,000 gal/day).  The pattern of variation for
phenol and solids content was similar to that for COD.

Variation in effluent characteristics among plants is illustrated
by the data in Table 29, which show the phenol and COD values  of
raw  waste  for  13 plants.  Also shown in the same table are the
COD values following a treatment consisting of  flocculation  and
sedimentation.   The phenol and COD values for the raw waste vary
over a wide range, as does the efficiency  of  the  treatment  as
judged by the percent reduction in COD after flocculation.

Biological Characteristics

Waste   water  from  the  wood  preserving  industry  is  usually
relatively treatable.  Limited experience  with  bench-scale  and
pilot   plant   activated  sludge,  trickling  filter,  and  soil
irrigation systems indicate that biological treating methods  are
generally  effective  in  reducing the oxygen demand and phenolic
compounds to acceptable levels.  Because these waste waters  have
a  very  low  nutrient  content,  the  addition  of  nitrogen and
phosphorus prior to biological treatment is necessary to maintain
a viable bacterial population.

Because of its prolonged exposure to temperatures in the range of
 110° to 121°C  (230° to 250°F) and its relatively high content  of
phenolic  compounds,  process water is sterile upon its discharge
from retorts.  Its successful biological treatment  requires  the
employment  of  strains  of bacteria that have been acclimated to
concentrations of phenolic compounds of 300 mg/1 or higher.  On a
laboratory scale, this  requirement  renders  BOD  determinations
difficult  to make and almost impossible to interpret, especially
as regards comparisons of results obtained by different analysts.
It is not possible to ascertain whether the differences  obtained
are  the  result  of  the characteristics of the waste samples or
differences in the bacterial cultures employed and  their  degree
of   acclimation  to  the  waste.   Dust  and  Thompson  obtained
differences in BOD values for creosote waste water of 200 percent
among several acclimated cultures of bacteria.

The correlation between BOD and COD  for  wood  preserving  waste
water is high.  Using creosote waste water with BOD values larger
than  150  mg/1,  the  above  authors  found  that  the  equation
BOD=0.497 COD * 60, for which r=0.985, accounted for  practically
all of the variation between the two parameters  (Figure 28).  The
general  applicability  of  this  equation  was indicated by spot
                               119

-------
ro
o
                  10
                   8
en

o
- 6
x
O
o
CD
                                                                                I   I
                                                           Y=0.497X+60
                                                j	i
                                                                i   i
                                    4       6       8       10      12
                                          Influent COD x 103 mg/l
                                                           14
16
                          FIGURE  28  -  RELATIONSHIP BETWEEN BOD AND COD FOP WASTEWATER
                                      FROM A CREOSOTE TREATING OPERATION

-------
                TABLE  29




PHENOL AND COD VALUES  FOR  EFFLUENTS  FROM
THIRTEEN WOOD PRESERVING PLANTS
COD (mg/1)
Plant
Location
Mississippi
Mississippi
Mississippi
Mississippi
Mississippi
Mississippi
Virginia
Virginia
Georgia
Georgia
Georgia
Tennessee
Louisiana
Phenol
(mg/1)
162
109
-
168
83
50
192
508
119
331
123
953
104
After
Raw Flocculation
6,290
11,490
48,000
42,000
12,300
1,000
9,330
32,300
7,440
3,370
17,100
1,990
10,500
3,700
5,025
2,040
31,500
4,500
-
3,180
8,575
2,360
1,880
3,830
1,990
6,070
Percent
Reduction
41
56
96
25
63
-
66
73
68
44
78
0
42
                 121

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  TABLE 30  RATIO BETWEEN COD AND BOD FOR VAPOR DRYING
           AND CREOSOTE EFFLUENT WASTEWATERS*

(NOTE:   Data provided by the Research Department,  Koppers
                        Company, Inc.)

                         (ing/liter)

Range of BOD
40 - 75





20 - 35



10 - 15



Average

COD
150
160
300
300
320
450
160
210
180
120
100
210
180
70
—

BOD
45
40
45
75
45
60
25
35
30
20
10
15
10
10
—
Ratio
COD/BOD
3.3
4.0
6.7
4.0
7.1
7.5
6.4
6.0
6.0
6.0
10.0
14,0*
18.0*
7.0
•6.2
*Analysis revealed these values to be statistical aberrants.
 They were not included in average.	

  TABLE 31  RANGE OF POLLUTANT CONCENTRATIONS IN WASTEWATER
            FROM A PLANT TREATING WITH CCA- AND FCAP-TYPE
                  PRESERVATIVES AND A FIRE RETARDANT
                         (mg/liter)	   _^_____
          Parameter
   Range of
Concentrations
COD
As
Phenols
Cu
Cr+6
Cr+3
F
P04
NH3-N
PH
10
13
0.05
0.05
0.23
0
4
15
80
5.0
- 50
- 50
- 0.16
- 1.1
- 1.5
- 0.8
- 20
- 150
- 200
- 6.8
                                122

-------
checks of the COD:BOD
plants.
ratio  for  similar  wastes  from  several
The  COD;BOD  ratio increases rapidly for BOD values smaller than
150 mg/1 (Table 30), and averages 6.2 for values in the range  of
20  to  40  mg/1.   This  ratio  is in line with the value of 6.1
reported for the petroleum  industry  for  effluents  similar  in
composition to those of the wood preserving industry.

Salt Type Preservatives and Fire Retardants

Waste waters resulting from treatments with inorganic salt formu-
lations  are  low in organic content, but contain traces of heavy
metals used in the preservatives and  fire  retardants  employed.
Average  analytical  data  based on weekly sampling for a year of
the effluent from a plant treating with both preservatives and  a
fire  retardant  are given in Table 31.  The presence and concen-
tration of a specific ion in waste water for such treatments  de-
pend  upon  the particular formulation employed and the extent to
which the waste is diluted by washwater and storm water.

Raw Waste Loading Data

Average analytical data for  5  typical  wood  preserving  plants
treating  with pentachlorophenol-petroleum solutions and/or creo-
sote are given in Tables  32  through  36.   Data  for  plants  1
through  4  (Tables 32-35) were obtained from 24 samples collected
at hourly intervals at the outfall from each plant  and  analyzed
separately  to  obtain  information  on  short-term  variation in
effluent quality.  These data were later supplemented by analysis
of several grab  samples  collected  over  a  period  of  several
months.   Data  for  plant  5  (Table 36) are based on a series of
grab samples collected during  1972.   Information  on  volume  of
discharge  of  process  water  was  obtained  either from 24-hour
measurements   (plants  1-4)  or  estimated  based  on  number  of
retorts,  processing  operations  used,  and other considerations
 (plant 5).  Waste volume flow data do not include cooling  water,
which  was  recycled  at  all  plants, coil condensate, or boiler
blowdown water.  Production figures for  1971 were estimated  from
the void volume of the retorts operated by the plants.

Raw  waste  loadings for each pollutant are expressed in terms of
concentrations  (mg/1) and kg/1000 cu m  of  product  treated  for
each  of  the  5 plants.  Maximum, minimum, and average raw waste
loadings per day based on analytical data and volume of discharge
are also given.  A composite  of  these  data,  representing  the
average  raw  waste  loadings  given  in Tables 32-36 is shown in
Table 37.  The effluent characteristics represented by these data
are assumed to be representative of  the  raw  waste  streams  of
plants  treating  with  creosote  and pentachlorophenol-petroleum
solutions.  Since each of the five plants involved is typical  of
the  industry,  data for the hypothetical plant given in Table 38
will be the basis for an  analysis  of  effluent  treatment  cost
presented later in this report.
                               123

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                           TABLE  32

                RAW WASTE LOADINGS FOR PLANT NO. 1

Raw Waste Loadings
Raw Waste
Loadings /Day (Kg)
Parenthetical values = Parenthetical values
Pounds/1000 Cubic Feet are in pounds
Parameter
COD

Phenols

Oils and
Grease
Total
Solids
Dissolved
Solids
Suspended
Solids
pH
Kg/1000 Cu-
(mE/1) bic Meters Prod. Max.
28,600 13,723.0
(854.8)
134 48.2
(3.0)
530 188.3
(11.7)
11,963 4,251.6
(264.9)
11,963 3,596.8
(224.1)
1,844 654.8
(40.8)

2,705.5
(5,952.0)
6.7
(14.8)
84.5
(186.0)
836.6
(1,840.5)
673.0
(1,480.6)
163.6
(359.9)
4.6
Min.
317.0
(697.5)
0.1
(.2)
4.2
(9.3)
5.0
(11.1)
2.3
(5.1)
3.3
(7.2)

Avg.
1,631.8
(3,590.0)
5.6
(12.4)
22.4
(49.3)
505.7
(1,112.6)
427.8
(941.1)
78.0
(171.5)


Avg. flow = 42,494 Ipd (11,227 gpd)
Void vol. of cylinders = 293 cubic meters  (10,337 cubic feet)
1971 production (est.) = 26,760 cubic meters  (945,000 cubic feet)
Avg. work days/yr. = 225
Avg. daily production = 119 cubic meters (4,200 cubic feet)
Preservatives = Creosote
                          124

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                            TABLE  33

                 RAW WASTE LOADINGS FOR  PLANT  NO.  2

Raw
Waste Loadings
Parenthetical values =
Pounds/1000 Cubic Feet
Parameter
COD
Phenols
Oils and
Grease
Total
Solids
Dissolved
Solids
Suspended
Solids
PH
(mg/1).
22,685
258
55
3,504
3,044
460

Kg/1000 Cu- ^
bic Meters Prod
7,712.
(480.
88.
(5.
19.
(1.
1,190.
(74.
1,035.
(64.
155.
(9.

0
5)
3
5)
3
2)
0
2)
2
5)
7
7)
4.9
Raw Waste
Loadings
/Day(Kg)

Parenthetical values
are in pounds
Max.
5,988.
(13,175.
54.
(120.
4.
(10.
728.
(1,603.
645.
(1,419.
95.
(210.


9
6)
7
3)
6
2)
8
4)
3
6)
7
6)

Min.
794
(1,746
9
(19
2
(4
118
(206
106
(234
16
(35


.0
.8)
.0
.9)
.0
.4)
.2
.0)
.5
.4)
.1
.4)

Avg.
1,546.7
(3,402.
17.
(38.
3.
(8.
238.
(525.
207.
(456.
31.
(69.


8)
6
7)
7
2)
9
6)
5
6)
4
0)


Avg. flow = 68,471 Ipd  (18,090  gpd)
Void Vol. of cylinders  = 427  cubic meters  (15,068 cubic feet)
Est. 1971 production =  60,163 cubic  meters  (2,124,588 cubic feet)
Avg. work days/yr. = 300
Avg. daily production - 201 cubic meters  (7,082  cubic feet)
Preservatives - Creosote, Pentachlorophenol
                         125

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                             TABLE 34

                  RAW WASTE LOADINGS FOR PLANT NO.  3
                  Raw Waste Loadings
                Parenthetical values =
                Pounds/1000 Cubic Feet
                          Kg/1000 Cu-
                                         Raw^Waste Loadings/Day(Kg)
                                           Parenthetical values
                                         	are in pounds	
Parameter
COD
Phenols
Oil
Total
Solids
Dissolved
Solids
Suspended
Solids
/mg/1)
12,467
82
150
1,724
1,528
196
bic Meters Prod.
3,295.1
(205.3)
25.7
(1.6)
40.1
(2.5)
455.8
(28.4)
404.5
(25.2)
51.4
(3.2)
Max.
943.2
(2,075.0)
5.9
(12.9)
25.0
(55.0)
130.3
(286.6)
115.5
(254.0)
14.8
(32.6)
Min.
500.0
(1,100.0)
3.5
(7.8)

69.5
(153.0)
61.6
(135.6)
7.9
(17.4)
Avg.
708.4
(1,558.4)
5.6
(12.3)
8.5
(18.8)
98.0
(215.5)
86.8
(191.0)
11.1
(24.5)
pH
                                    4.5
Avg. flow (est.) = 56,775 Ipd  (15,000  gpd)
Void vol. of cylinders = 457 cubic meters  (16,152  cubic  feet)
Est. 1971 production * 64,491  cubic meters  (2,277,432  cubic  feet)
Avg. work days/yr. = 300
Avg. daily production * 215 cubic meters  (7,591  cubic  feet)
Preservatives - Creosote, Pentachlorophenol
                        126

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                             TABLE 35

                  RAW WASTE LOADINGS FOR PLANT NO. 4

Raw
Waste Loadings
Parenthetical values =
Pounds/1000 Cubic Feet
Parameter
COD
Phenols
Oil
Total
Solids
Dissolved
Suspended
Solids
pH
(mg/1)
9,318
312
580
3,432
2,748
684

Kg/1000 Cu-
bic Meters Prod.
2,291.
(142.
77.
(4.
142.
(8.
844.
(52.
675.
(42.
168.
(42.

9
8)
0
8)
8
9
2
6)
7
1)
5
1)
5.8
Raw Waste
LoadinBs/Day (kg)
Parenthetical values
are in pounds
Max.
1,131.
(2,489.
21.
(46.
45.
(100.
530.
(1,166
383.
(842.
147.
(324.


7
8)
2
6)
8
8)
3
.7)
1
4)
4
2)

Min.
373
(822
14
(32
24
(53
99
(219
93
(206
6
(13


.1
.6)
.6
.2)
.5
.9)
.9
.7)
.8
.4)
.0
.3)

Avg.
563.
(1,239.
18.
(41.
35.
(77.
207.
(456.
166.
(365.
41.
(90.

3
3)
9
5)
0
1)
5
5)
1
5)
3
9)


Avg. flow (est.) = 60,560 Ipd (16,000 gpd)
Void vol. of cylinders = 523 cubic meters  (18,470 cubic feet)
Est 1971 production = 73,746 cubic meters  (2,604,270 cubic feet)
Avg. work days/yr. - 300
Avg. daily production = 246 cubic meters  (8,681 cubic feet)
Preservatives - Creosote, Pentachlorophenol
                              127

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                            TABLE 36

                  RAW WASTE LOADINGS FOR PLANT NO. 5
Raw Waste Loadings
Parenthetical values =
Pounds/1000 Cubic Feet
Parameter
COD
Phenols
Oils and
Grease
Total
Solids
Dissolved
Solids
Suspended
Solids
PH
Kg/1000 Cu-
(mg/1) bic Meters Prod.
13,273 3,072.
(191.
126 28.
(1.
172 40.
(2.
5,780 1,338.
(83.
5,416 1,253.
f ~f Q
{. I 0 .
364 83.
(5.

0
4)
9
8)
1
5)
6
*)
5
1)
5
2)
4.5
Raw Waste
Loadings /Bay (kg)
Parenthetical values
are in pounds
Max
593
(1,305
5
(11
9
(21
259
(570
241
(532
—


.2
.0)
.1
.2)
.9
.8)
,5
.9)
.8
.0)
—

Min.
317
(699
3
(7
1
(2
168
(370
137
(303
—


.8
.1)
.4
.4)
.0
.3)
.3
.2)
.9
.4)
—

Avg.
452
(995
4
(9
5
(12
197
(433
184
(406
12
(27


.5
.5)
.3
.4)
.9
.9)
.0
.5)
.6
.2)
.4
.3)


Void vol. of cylinders = 356 cubic meters  (12,557  cubic  feet)
Est. 1971 production =44,175 cubic meters  (1,560,000  cubic  feet)
Avg. work days/yr. = 300
Avg. daily production = 147 cubic meters  (5,200  cubic  feet)
Preservatives - Creosote, Pentachlorophenol
                        128

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                             TABLE 37

     AVERAGE RAW WASTE LOADINGS FOR FIVE WOOD-PRESERVING PLANTS
Parameter
COD
Phenols
Oils and
Grease
Total
Solids
Dissolved
Solids
Suspended
Solids
pH
Raw Waste Loadings
Parenthetical values =
Pounds/1000 Cubic Feet
Kg/1000 Cu-
(mg/1) bic Meters Prod.
19,269 5,378.4
(335.1)
182 51.4
(3.2)
297 83.5
(5.2)
5,280 1,463.8
(91.2)
4,571 1,276.0
(79.5)
710 199.0
(12.4)
4.9
Raw Waste Loadings/Day (kg)
Parenthetical values
are in pounds
Max.
1,651.9
(3,634.2)
12.8
(28.2)
37.5
(82.5)
470.7
(1,035.5)
387.4
(852.2)
87.2
(191.9)

Min.
502.9
(1,106.3)
6.3
(13.8)
7.5
(16.4)
109.5
(240.9)
93.5
(205.8)
12.2
(26.8)

Avg.
1,016.0
(2,235.2)
9.6
(21.1)
15.6
(34.4)
278.4
(612.5)
241.0
(530.2)
37.5
(82.4)


Avg. flow = 52,990 Ipd  (14,000 gpd)
Void vol. of cylinders = 411 cubic meters  (14,517  cubic  feet)
Est. 1971 Production = 53,867 cubic meters  (1,902,258  cubic  feet)
Avg. work days/yr. = 285
Avg. daily production = 189 cubic meters  (6,674  cubic  feet)
Preservatives - Creosote, Pentachlorophenol
                               129

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Sources of Waste Water

Waste waters from wood preserving operations are of the following
types and contain the contaminants indicated:

a.   Condensate  from  conditioning by steaming: This is the most
heavily contaminated waste water,  since  it  comes  into  direct
contact  with  the  preservative  being  used.   condensates from
pentachlorophenol and creosote treatments contain entrained oils,
phenolic compounds, and  carbohydrates  leached  from  the  wood.
Those  from  salt-type treatments contain traces of the chemicals
present in the preservative formulation used.  The oxygen  demand
of  this waste is high because of dissolved wood extractives and,
in  the  case  of  creosote  and  pentachlorophenol   treatments,
entrained oils.

b.  Cooling water:  Cooling water is used to cool condensers, air
compressors, and vacuum pumps and, in the case of plants that use
it on a once-through basis, accounts for approximately 80 percent
of.  the total discharge.  Water used with surface condensers, air
compressors, and dry-type vacuum pumps is unchanged  in  quality.
That used with barometric condensers and wet-type vacuum pumps is
contaminated with the preservative, unless the preservative is of
the  water-borne  type.  In the latter case, the cooling water is
unchanged in quality.

c.  Steam condensate from heating coils:  Water from this  source
is  uncontaminated,  unless  a coil develops a leak through which
preservative can enter.

d.  Boiler blowdown  water:   This  water  is  contaminated  with
chemicals,  principally  chromates and phosphates, used as boiler
compounds.


e.  Vacuum water:  Water  extracted  from  the  wood  during  the
vacuum  cycle  following  steam conditioning is contaminated with
the preservative employed.  In the  Boulton  process,  the  waste
water is largely composed of water from this source.

f.   Wash  water:   Water used to clean equipment is contaminated
with the preservative used, with oil and  grease,  and  may  also
contain detergents.

g.   Water  softener  brine:   Water  used  for  this  purpose is
contaminated with various dissolved inorganic materials including
salts of calcium and magnesium.

The source and volume of water used,  including  recycled  water,
and  the  amount of waste water discharged by a hypothetical wood
preserving plant  (Table 37) that employs steam  conditioning  are
shown  in  Figure 29.  A more complete breakdown of these data is
given in Table 38.  A  representative  plant  has  an  intake  of
approximately  121,120  1/day  (32,000 gal/day), gross water usage
                              130

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                          TABLE 38

   SOURCE AND VOLUME OF WATER DISCHARGED AND RECYCLED PER
DAY BY A TYPICAL WOOD PRESERVING PLANT

Source
Cylinder condensate
Coil condensate
Boiler blowdown
Vacuum Water
Cooling water
Other
TOTAL
Volume
Used
51,096
(13,500)
55,640
(14,700)
6,813
(1,800)
-
454,200
(120,000)
1,892
(500)
567,500
(150,500)
Volume Volume
Discharged Recycled
51,098
(13,500)
44,474 (b
(11,750)
6,813
(1,800)
6,434 (a
(1,700)
13,248 (c 440,952
(3,500)(b (116,500)
1,892
(500)
104,277 447,387
(27,550) (118,200)
Open values are in liters.
Parenthetical values are in gallons
a) Water extracted from wood and recycled as cooling water.
b) Approximately 15 percent loss due to flash evaporation.
c) Loss of cooling water by drift and evaporation.

Note:  Based on hypothetical plant, data for which are  given
       in TABLE 3 .
                              131

-------
of 567,750 1/day (150,000 gal/day), and a  discharge  of  104,100
1/day   (27,500  gal/day).   An  estimated  13,250  I/day  (3,500
gal/day) of cooling  water  are  lost  by  evaporation.   Roughly
446,650  I/day  (118,000  gal/day)  are recycled as cooling water,
including 6,400 I/day (1,700 gal/day) of water  extracted  during
the  conditioning  process  (vacuum water)•  The amount of vacuum
water recovered averages about 1.9 kg/cu  m  (4.3  Ib/cu  ft)   of
green  wood  that  is steam conditioned.  Approximately two times
this amount of vacuum water is removed from Boultonized stock.
The actual volume of water used at a plant of this size and  type
is  not  static,  but  varies depending upon the condition of the
stock (either green or seasoned) being treated and  the  size  of
the  individual  items.  For illustrative purposes only, the data
in Table 38 were computed based on the assumption that the  plant
treated  stock  one-half of which was green and one-half of which
was seasoned.  If all green material were treated, the volume  of
boiler water and cooling water used would approximately double.

Both  the  gross  water used in a plant and the volume discharged
depends primarily upon whether a plant uses cooling  water  on  a
once  through  basis  or  recycles  it.   To a lesser extent, the
disposition of coil condensate either reused for  boiler  make-up
water  or  discharged is also important in determining the volume
of waste water.  Nationwide,  approximately  75  percent  of  the
plants  recycle  their cooling water; only 33 percent reuse their
coil condensate.

Gross water usage is also influenced by  cooling  water  require-
ments.   Among plants of the same size and type of operation, the
volume used varies by as much as  fourfold.   Such  variation  is
attributable   to   the  operating  procedures  used.   Important
variables in this regard are the length  of  the  vacuum  period,
during which cooling water is required for both the condenser and
the  vacuum  pump,  and  whether  or  not the rate of flow to the
condenser is reduced after the initial period of operation when a
high flow rate is needed.

Volume of cooling water used also varies  with  the  conditioning
process  used  -  either steaming or Boultonizing.  In the former
process, the condenser is operated only about  three  hours  fol-
lowing  a  conditioning  cycle.  In the Boultonizing process, the
condenser is operated for the entire period, which often  exceeds
30  hours.  Gross cooling water usage at a larger plant employing
the Boulton process may amount to 3.8 million  I/day   (1  million
gal/day).

Assuming recycling of cooling and coil condensate water, the most
important  source  of waste water in terms of volume and level of
contamination is cylinder condensate.  The amount of waste  water
from  this  source  varies with the volume of stock that is green
and must be conditioned prior  to  preservative  treatment.   For
plants  operating  on  similar steaming or Boultonizing schedules
                               132

-------
Intake
                                                    9al-
       11,166
       (2,950)-.--

(Evaporation) 102]

113
(3Q



6,
550 0,
000> 440,952
' (116,500)


J2
"o
s£
^^ ^r
<«
*-
u. 5
^> **
H 0
Wi-
O

• •
102
&.









384
050)
454
(120








813
BOO)
6,434 V
(1,700) (5
200
000)

O
z

-1
O
O
O




4>
**
CO
6
3
3
O
Ml
>











892
00)



CO
(O
UJ
u
O
C£
Q.
^•B

14J248 1,
(3^500) (Evaporation) (s
X
«a»









892
00)
104,277
Waste (27,550)
     FIGURE 29 - SOURCE AND  VOLUME OF DAILY WATER USE  AND RECYCLING AND
                 WASTEWATER  SOURCE AT A TYPICAL WOOD-PRESERVING PLANT
                                133

-------
the volume of waste does not vary widely  among   plants   of   com-
parable  size  and  generally  is   less than  75,500  I/day (20,000
gal/day) .
                               134

-------
                           SECTION VI

                      POLLUTANT PARAMETERS
Presented below is  a  discussion  of  pollutants  and  pollutant
parameters  that  may be present in process waters in the portion
of the timber products processing industry that is the subject of
this effluent guidelines and standards development document.

Certain of these parameters are common to all  the  subcategories
covered  by  this  document,  although  the concentrations in the
process water and the absolute  amounts  generated  per  unit  of
production vary considerably among the subcategories.

Review  of published information. Refuse Act Permit applications,
industry data, and information generated during  the  survey  and
analysis  phase  of  this effluent guidelines development program
determined that the following pollutants or pollutant  parameters
are common to all of the subcategories:

         Biochemical Oxygen Demand  (BOD5)
         Chemical Oxygen Demand
         Phenols
         Oil and Grease
         pH
         Temperature
         Dissolved Solids
         Total Suspended Solids
         Phosphorus
         Ammonia

The   wood   preserving  subcategories  may  have  the  following
pollutants or  pollutant  parameters  present  in  process  water
flows:

         Copper
         Chromium
         Arsenic
         Zinc
         Flourides

The  above  listed  pollutants  or  pollutant  parameters are, of
course, not present in process water from all  the  subcategories
for which effluent guidelines and standards are presented in this
document.  Their presence depends on a number of factors, such as
processing method, raw materials used, and chemicals added to the
process.

Following  is  a  discussion  of  the  significant pollutants and
pollutant parameters.
                              135

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Biochemical Oxygen Demand (BODS)

Biochemical oxygen demand  (BOD)   is  a  measure  of  the  oxygen
consuming capabilities of organic matter.  The Biochemical Oxygen
Demand  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  Biochemical  Oxygen
Demand,  which can 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  Biochemical  Oxygen  Demand
indicates  the  presence  of  decomposing  organic   matter   and
subsequent  high  bacterial  counts  that degrade its quality and
potential uses.

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  DO  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 as a result  or  a
high BOD can kill all inhabitants of the affected area.

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.

ChemicaliOxygen Demand  (COD)

Chemical oxygen demand  (COD) provides a measure of the equivalent
oxygen required to oxidize the  organic  material  present  in  a
waste  water  sample,  under  acid  conditions  with the aid of a
strong chemical oxidant, such  as  potassium  dichromate,  and  a
catalyst   (silver  sulfate).  One major advantage of the COD test
is that the results are available normally  in  less  than  three
hours.  However, one major disadvantage is that the COD test does
not  differentiate  between  biodegradable  and  nonbiodegradable
organic  material.   In  addition,  the  presence  of   inorganic
reducing  chemicals   (sulfides, etc.) and chlorides may interfere
with the COD test.  In  certain  cases  where  a  definite  ratio
                              136

-------
between  BOD5 and COD can often serve as an indicator of organics
that are not readily biodegradable.

Phenols

Phenols and phenolic wastes are derived from petroleum, coke, and
chemical industries; wood distillation; and domestic  and  animal
wastes.  Many phenolic.compounds are more toxic than pure phenol;
their toxicity varies with the combinations and general nature of
total  wastes.   The effect of combinations of different phenolic
compounds is cumulative.

Phenols and phenolic compounds are both acutely  and  chronically
toxic  to  fish  and  other aquatic animals.  Also, chlorophenols
produce an unpleasant taste in fish  flesh  that  destroys  their
commercial value.

It is necessary to limit phenolic compounds in raw water used for
drinking  water  supplies, as conventional treatment methods used
by water supply facilities do not remove phenols.  The  ingestion
of  concentrated solutions of phenols will result in severe pain,
renal irritation, shock and possibly death.

Phenols also reduce the utility of water for  certain  industrial
uses,  notably  food  and  beverage  processing, where it creates
unpleasant tastes and odors in the product.


Oil and Grease

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
exhibit 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  coats  of  water  animals  and
fowls.   Oil and grease in a water can result in the formation of
objectionable  surface  slicks  preventing  the  full   aesthetic
enjoyment of the water.

Oil  spills  can  damage the surface of boats and can destroy the
aesthetic characteristics of beaches and shorelines.

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
                               137

-------
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
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
consumed  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.

Fish  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
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tolerance limit for the population.  This could seriously  affect
fish that depend on benthic 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.

Rising   temperatures  stimulate  the  decomposition  of  sludge,
formation of sludge gasr 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 estuarine
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.

EM/ 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 substances 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 advantageous 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 stress conditions or
kill   aquatic life outright.  Dead fish, associated algal blooms,
and, foul stenches are  aesthetic  liabilities  to  any  waterway.
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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 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.  Ammonia is
more lethal with a higher pH.

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.

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  U.S. 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
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.

Waters  with total dissolved solids over 500 mg/1 have decreasing
utility as irrigation  water.   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
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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.

Total Suspended Solids

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 fish 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 be present in sufficient concentration to be objectionable or
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  bed  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
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  sludge   worms   and
associated organisms.
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Turbidity  is  principally  a  measure  of  the  light  absorbing
properties of suspended solids.  It may be used as  a  substitute
method  of quickly estimating the total suspended solids when the
concentration is relatively  low  and  a  correlation  factor  is
available.
Phosphorus

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 reasons, 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  an  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 substrate and breeding ground for flies.

Phosphorus in the  elemental  form  is  particularly  toxic,  and
subject  to  bioaccumulation  in  much  the  same way as mercury.
Colloidal elemental phosphorus will poison marine  fish   (causing
skin  tissue  breakdown  and discoloration).  Also, phosphorus is
capable of being concentrated and will accumulate in  organs  and
soft  tissues.   Experiments  have  shown  that  marine fish will
concentrate phosphorus from  water  containing  as  little  as  1
microgram/1(ug/1).

Ammonia

Ammonia  is  a  common  product  of  the decomposition of  organic
matter.  Dead and decaying animals and plants  along  with human
and  animal  body wastes account for much of the ammonia entering
the aquatic ecosystem.  Ammonia exists in  its  non-ionized  form
only  at  higher  pH  levels and is the most toxic in this state.
The lower the pH, the more ionized  ammonia  is  formed  and  its
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toxicity  decreases.   Ammonia,  in  the  presence  of  dissolved
oxygen, is converted to nitrate  (NO^)   by  nitrifying  bacteria.
Nitrite   (NO£),  which is an intermediate product between ammonia
and nitrate, sometimes occurs in quantity when  depressed  oxygen
conditions  permit.   Ammonia can exist in several other chemical
combinations including ammonium chloride and other salts.

Nitrates are considered to be among the poisonous ingredients  of
mineralized  waters,  with potassium nitrate being more poisonous
than sodium nitrate.  Excess nitrates  cause  irritation  of  the
mucous linings of the gastrointestinal tract and the bladder; the
symptoms  are  diarrhea  and  diuresis, and drinking one liter of
water containing 500 mg/1 of nitrate can cause such symptoms.

Infant methemoglobinemia,  a  disease  characterized  by  certain
specific  blood  changes  and  cyanosis,  may  be  caused by high
nitrate concentrations in the water used  for  preparing  feeding
formulae.    While  it  is  still  impossible  to  state  precise
concentration limits, it has been widely recommended  that  water
containing  more  than 10 mg/1 of nitrate nitrogen (NC)3-N) should
not  be  used  for  infants.   Nitrates  are  also   harmful   in
fermentation processes and can cause disagreeable tastes in beer.
In  most  natural  water  the pH range is such that ammonium ions
 (NH^+)  predominate.    In   alkaline   waters,   however,   high
concentrations  of  un-ionized  ammonia in undissociated ammonium
hydroxide increase the toxicity of ammonia solutions.  In streams
polluted with sewage, up to one  half  of  the  nitrogen  in  the
sewage  may  be in the form of free ammonia, and sewage may carry
up to 35 mg/1 of total nitrogen.  It has been  shown  that  at   a
level  of  1.0 mg/1 un-ionized ammonia, the ability of hemoglobin
to combine with  oxygen  is  impaired  and  fish  may  suffocate.
Evidence  indicates  that  ammonia  exerts  a  considerable toxic
effect on all aquatic life within a range of less than  1.0  mg/1
to  25  mg/1,  depending  on  the  pH  and dissolved oxygen level
present.

Ammonia can add to the problem  of  eutrophication  by  supplying
nitrogen  through  its  breakdown products.  Some lakes in warmer
climates, and others that are aging quickly are sometimes limited
by the nitrogen available.  Any increase will speed up the  plant
growth and decay process.
Copper   salts   occur  in   natural   surface  waters  only in trace
amounts, up to  about  0.05  mg/1,  so  that their presence  generally
is  the  result of   pollution.   This  is  attributable  to  the
corrosive action of the water on copper  and  brass  tubing,  to
industrial  effluents,  and  frequently   to  the  use  of  copper
compounds for the control  of undesirable  plankton organisms.

Copper is not considered to be a cumulative systemic  poison  for
humans,  but it  can cause symptoms of  gastroenteritis, with nausea
and   intestinal irritations,,  at   relatively  low  dosages.  The
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limiting factor in domestic water supplies is  taste.   Threshold
concentrations  for  taste  have  been  generally reported in the
range of 1.0-2.0 mg/1 of copper, while as 5mg/l makes  the  water
completely unpalatable.

The toxicity of copper to aquatic organisms varies significantly,
not  only  with  the  species,  but  also  with  the physical and
chemical characteristics of  the  water,  including  temperature,
hardness,  turbidity, and carbon dioxide content.  In hard water,
the toxicity of copper salts is reduced by the  precipitation  of
copper  carbonate  or other insoluble compounds.  The sulfates of
copper and zinc, and of copper and  cadmium  are  synergistic  in
their toxic effect on fish.

Copper  concentrations  less than 1 mg/1 have been reported to be
toxic, particularly  in  soft  water,  to  many  kinds  of  fish,
crustaceans,  mollusks,  insects,  phytoplankton and zooplankton.
Concentrations of copper, for example, are  detrimental  to  some
oysters above 0.1 mg/1.  Oysters cultured in sea water containing
0.13-0.5  mg/1  of copper deposited the metal in their bodies and
became unfit as a food substance.

Chromium

Chromium, in its various valence states, is hazardous to man.  It
can  produce  lung  tumors  when   inhaled   and   induces   skin
sensitizations.   Large doses of chromates have corrosive effects
on the  intestinal  tract  and  can  cause  inflammation  of  the
kidneys.   Levels  of  chromate  ions  that have no effect on man
appear to be so low that they are below detectable limits.

The toxicity of chromium salts toward aquatic life varies  widely
with  the  species, temperature, pH, valence of the chromium, and
synergistic or antagonistic effects, especially that of hardness.
Fish are relatively tolerant of chromium  salts,  but  fish 'food
organisms  and  other  lower  forms of aquatic life are extremely
sensitive.  Chromium also inhibits the growth of algae.

In some agricultural crops, chromium can cause reduced growth  or
death  of  the  crop.   Adverse  effects of low concentrations of
chromium on corn, tobacco and sugar beets have been documented.

Arsenic

Arsenic is found to a small extent in  nature  in  the  elemental
form.   It occurs mostly in the form of arsenites of metals or as
pyrites.

Arsenic is normally present in sea water at concentrations  of  2
to  3  ug/1  and  tends  to  be  accumulated by oysters and other
shellfish.  Concentrations of 100 mg/kg  have  been  reported  in
certain shellfish.  Arsenic is a cumulative poison with long-term
chronic  effects  on  both  aquatic  organisms  and  on mammalian
species and a succession of small doses may add  up  to  a  final
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lethal  dose.   It is moderately toxic to plants and highly toxic
to animals especially as AsH3.

Arsenic trioxide, whicji also is exceedingly toxic, was studied in
concentrations of 1.96 to 40 mg/1 and found to be harmful in that
range to fish and other aquatic life.   Work  by  the  Washington
Department  of Fisheries on pink salmon has shown that at a level
of 5.3 mg/1 of As.20.3 for 8 days was  extremely  harmful  to  this
species;  on  mussels,  a  level of 16 mg/1 was lethal in 3 to 16
days.             |

severe human poisoning can result from 100 mg concentrations, and
130 mg has proved fatal.  Arsenic  can  accumulate  in  the  body
faster  than  it  is excreted and can build to toxic levels, from
small amounts taken  periodically  through  lung  and  intestinal
walls from the airr water and food.

Arsenic   is   a   normal   constituent   of   most  soils,  with
concentrations ranging  up  to  500  mg/kg.   Although  very  low
concentrations  of arsenates may actually stimulate plant growth,
the presence of excessive soluble arsenic  in  irrigation  waters
will  reduce  the yield of crops, the main effect appearing to be
the destruction of chlorophyll in the foliage.  Plants  grown  in
water  containing 1 mg/1 of arsenic trioxides showed a blackening
of the vascular bundles in the leaves.  Beans and  cucumbers  are
very   sensitive,   while   turnips,  cereals,  and  grasses  are
relatively resistant.   Old  orchard  soils  in  Washington  that
contained  4 to 12 mg/kg of arsenic trioxide in the top soil were
found to have become unproductive,

Zinc
                    &
Occurring abundantly in rocks and ores, zinc is  readily  refined
into a stable pure metal and is used extensively for galvanizing,
in  alloys, for electrical purposes, in printing plates, for dye-
manufacture  and  for  dyeing  processes,  and  for  many   other
industrial  purposes.   Zinc  salts  are  used in paint pigments,
cosmetics,  Pharmaceuticals,  dyes,   insecticides,   and   other
products too numerous to list herein.  Many of these salts  (e.g.,
zinc  chloride  and  zinc  sulfate)  are highly soluble in water;
hence it is  to  be  expected  that  zinc  might  occur  in  many
industrial  wastes.   On  the  other  hand, some zinc salts  (zinc
carbonate, zinc oxide, zinc sulfide) are insoluble in  water  and
consequently it is to be expected that some zinc will precipitate
and be removed readily in most natural waters.
                                     »
In   zinc-mining   areas,  zinc  has  been  found  in  waters  in
concentrations as high as 50 mg/1 and in  effluents  from  metal-
plating  works  and  small-arms ammunition plants it may occur in
significant concentrations.  In most surface and  ground  waters,
it is present only in trace amounts.  There is some evidence that
zinc   ions  are  adsorbed  strongly  and  permanently  on  silt,
resulting in inactivation of the zinc.
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Concentrations of zinc in excess of 5 mg/1 in raw water used  for
drinking water supplies cause an undesirable taste which persists
through  conventional treatment.  Zinc can have an adverse effect
on man and animals at high concentrations.

In soft water, concentrations of• zinc ranging  from  0.1  to  1.0
mg/1 have been reported to be lethal to fish.  Zinc is thought to
exert  its  toxic  action by forming insoluble compounds with the
mucous that covers the gills, by damage to the  gill  epithelium,
or  possibly by acting as an internal poison.  The sensitivity of
fish to zinc varies with species, age and condition, as  well  as
with  the  physical  and  chemical  characteristics of the water.
Some acclimatization to the presence of zinc is possible.  It has
also been observed that the effects of  zinc  poisoning  may  not
become  apparent  immediately,  so  that  fj.sji removed from zinc-
contaminated to zinc-free water (after 4-6 hours of  exposure  to
zinc)   may  die  48 hours later.  The presence of copper in water
may increase the toxicity of zinc to aquatic organisms,  but  the
presence  of  calcium  or  hardness  may  decrease  the  relative
toxicity.

Observed values for the distribution of zinc in ocean waters vary
widely.  The major concern with zinc compounds in  marine  waters
is  not  one  of acute toxicity, but rather of the long-term sub-
lethal effects of the metallic compounds and complexes.  From  an
acute toxicity point of view, invertebrate marine animals seem to
be  the  most  sensitive organisms tested.  The growth of the sea
urchin, for example, has been retarded by as little as 30 ug/1 of
zinc.

Zinc sulfate has also been found to be lethal to many plants, and
it could impair agricultural uses.


Fluorides

As the most reactive non-metal, fluorine is never found  free  in
nature  but  as  a  constituent of fluorite or fluorspar, calcium
fluoride, in sedimentary  rocks  and  also  of  cryolite,  sodium
aluminum  fluoride, in igneous rocks.  Owing to their origin only
in certain types of rocks and only in a few regions, fluorides in
high concentrations are  not  a  common  constituent  of  natural
surface  waters, but they may occur in detrimental concentrations
in ground waters.

Fluorides are used  as  insecticides,  for  disinfecting  brewery
apparatus,  as a flux in the* manufacture of steel, for preserving
wood and mucilages, for the manufacture of glass and enamels,  in
chemical industries, for water treatment, and for other uses.

Fluorides  in sufficient quantity are toxic to humans, with doses
of 250 to 450 mg giving severe symptoms or causing death.

There are numerous articles describing the effects  of  fluoride-
bearing  waters  on dental enamel of children; these studies lead
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to the generalization that water containing less than 0.9 to  1.0
mg/1  of  fluoride  will seldom cause mottled enamel in children,
and for adults, concentrations less than 3  or  4  mg/1  are  not
likely   to  cause  endemic  cumulative  fluorosis  and  skeletal
effects.  Abundant literature is also  available  describing  the
advantages  of  maintaining  0.8  to  1.5 mg/1 of fluoride ion in
drinking  water  to  aid  in  the  reduction  of  dental   decay,
especially among children.

Chronic  fluoride  poisoning  of  livestock  has been observed in
areas  where  water   contained   10   to   15   mg/1   fluoride.
Concentrations of 30 - 50 mg/1 of fluoride in the total ration of
dairy  cows  is  considered  the upper safe limit.  Fluoride from
waters apparently  does  not  accumulate  in  soft  tissue  to  a
significant  degree  and it is transferred to a very small extent
into the milk and to a somewhat greater degree into  eggs.   Data
for  fresh  water  indicate  that  fluorides are toxic to fish at
concentrations higher than 1.5 mg/1.
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                           SECTION VII

                CONTROL AND TREATMENT TECHNOLOGY

BARKING

Logs are barked by a variety of abrasion and  pressure  processes
as  described  in  detail  in  Section  III.  Ring and cutterhead
barkers produce a solid waste composed of chipped dry bark, which
may be sent to the hog to be shredded and then to the bark boiler
("hog boiler") for use as fuel.  Wet drum barkers,  bag  (pocket)
barkers,  and  hydraulic  barkers,  require steps to separate the
abraded bark from the water*  The  bark  is  usually  pressed  to
remove water, and sent to the boiler, again for use as fuel.  The
water  can  be recycled.  The volume requirements, in addition to
the quality requirments of supply water to the hydraulic  barking
operation,  result  in a significant difference in procedures and
practices for handling the process  contact  water  generated  by
this operation.

Hydraulic Barking

The  volume of water used in this method of barking range between
50,000 and 120,000 1/cu m (370 to 890 gal/cu ft)  of  wood.   Raw
effluent  from  hydraulic  barkers ranges between 56 and 250 mg/1
BOD and 500 to 2400 mg/1 suspended solids.  Primary settling  can
reduce suspended solids to less than 250 mg/1.

Opportunity  for  disposal  of  these  volumes of waste water are
limited in  many  segments  of  the  timber  products  processing
category.   With the exception of the pulp and paper, the volumes
generated by hydraulic barking are in excess of the  amount  that
could  be  utilized in other unit operations of the manufacturing
process.

Because  little  information  was  available  on   the   separate
treatment  of  hydraulic  barker  effluent, treatment and control
technology will be applied from another industry,  the  pulp  and
paper  industry.   It  is  noted,  however,  that  water  from  a
hydraulic barker is being sucessfully recycled by  at  least  one
timber products processing plant.

In  the  pulp  industry,  modern practice is the use of circular,
heavy-duty type clarifiers or thickeners.  These are designed for
a rise rate of 40,700 to 48,900 1/sq m/day  (1000 to  1200  gal/sq
ft/day)  of  surface  area  and  to provide a retention period of
about two hours.  They are equipped and  piped  to  handle  dense
sludge  as  well  as  having  a  skimmer  to collect the floating
materials.  The under flow is  removed  by  means  of  diaphragm,
plunger,  or  screw  pumps and transferred to drying beds or to a
vacuum filter for dewatering.  Filter media  frequently  consists
of  120-mesh  stainless  steel  wire cloth.  Filter cake produced
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contains about 30 percent solids and loadings range from  235  to
284  kg/sq m of dry solids.  Such cakes are either disposed of on
the land or sold as mulch.

Effluents  from  clarifiers  are  usually  not  treated   further
separately  but  combined  with  pulp  mill  and other wastes for
biological treatment, which can be 85% to 95% effective.
VENEER

Treatment and control  technology  in  the  veneer  manufacturing
industry is not extensive.  The major effort made by this segment
of  the  industry  to  reduce  waste  water discharge has been to
reduce the amount of waste water by  reuse  and  conservation  of
water  and  to  contain waste waters that cannot be reused.  Each
source of potential waste  water  and  methods  of  treatment  is
discussed below.
Log Conditioning

Waste  water  from  log  conditioning may be the largest and most
difficult source to handle in a veneer mill.

Although seldom used, biological treatment of the  effluent  from
hot  water  vats  and  steam  vats  used  in  log conditioning is
practicable and effective.  It has been reported that  85  to  90
percent  reduction  of  BOD  is  attainable  by  using lagoons or
aerated lagoons.  Other types of biological  treatment  have  not
been  reported,  but  it  is obvious that conventional biological
processes such as the activated sludge  process  are  also  tech-
nically feasible.

Hot water vats when heated indirectly through coils will not have
a continuous discharge caused by steam condensate.  Any discharge
results  from  spillage when logs are either placed into or taken
out of the vat or from periodic cleaning.   Plants  operating  in
this  manner  need  only to settle the water in settling tanks or
ponds and reuse the water for any makeup that might be  required.
There  are  several  plants  designed  to operate in this manner;
however, the tendency has generally been to operate  this  system
by  injecting  live  steam into the vats to heat the water to the
desired  level  and  then  to  use  the  steam  to  maintain  the
temperature.   The  reason  for the use of steam injection rather
than heating coils is to raise  the  temperature  as  quickly  as
possible.   Quicker  indirect heating may also be accomplished by
adding more heating surface to the vats.  Plants that  use  steam
coils in their hot water vats and then settle and reuse the water
have  experienced a decreased pH in the vats with time.  Addition
of lime or sodium hydroxide may be necessary to control corrosive
activity.  The resulting sludge may be trucked to landfill.
                              150

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Waste water discharge  from  steam  vats  is  more  difficult  to
eliminate.   Condensate  from the vats must be discharged because
of  the  difficulty  of  reusing  the  contaminated   condensate.
Various  modifications  have  been made to steam vats which allow
them to be converted to totally closed systems.   Several  plants
have  converted steam vats to hot water spray tunnels which would
have conditioning effects similar to hot water vats.   Hot  water
does  not  heat  the  logs  as  rapidly or as violently as direct
steam; however, it is a practical alternative  for  most  plants.
While  many  mills  cannot use hot water vats because of the fact
that some species of logs do not sink, hot water  sprays  can  be
used  as  an alternative and can be placed in existing steam vats
with  only  minor  modifications.   These  systems  work  on  the
principle  of  heating water through heat exchange coils and then
spraying the hot water over the logs.  The hot water can then  be
collected and reused after settling and screening.

The  other  possible  modification  is a technology from the wood
preserving  industry  called   "modified   steaming."    Modified
steaming works on principles similar to hot water sprays with the
exception  that  no  sprays are used.  Coils in the bottom of the
vat are  used  to  produce  steam  from  the  water.   The  steam
conditions  the  log  in  much the same manner as in conventional
steam vats,  As the steam condenses, it falls to  the  bottom  of
the vat where it is revaporized.

Either  the use of hot water sprays or the employment of modified
steaming would allow mills that now use  steam  vats  to  operate
similarly  to  mills  that  now use hot water vats without direct
steam impingement.  All of these methods are closed systems  and,
therefore, require some type of solids removal and "flush-outs"  a
few  times  each year.  They may also require pH adjustment.  The
small volumes of waste water  produced  during  the  "flush-outs"
could then be contained or used for irrigation.

Veneer Dryers

The  practice  of  cleaning  veneer dryers with water is one that
will necessarily continue.  However, the  frequency  of  cleaning
and the volume of wash water can be significantly reduced.

Veneer and plywood mills producing 9.3 million sq m per year  (100
million  sq  ft)  on  a 9.53 mm  (3/8 in) basis may use as much as
57,000 I/week  (15,000 gal) of water to clean dryers.   There  are
many  modifications  to cleaning procedures which can reduce this
volume.  A plywood mill in Oregon has already reduced its  veneer
dryer  washwater  to  8,000  1/weeJc   (2,000 gal/week) by manually
scraping the dryer and blowing it  out  with  air  prior  to  the
application  of  water.   Close  supervision of operators and the
installation of water meters on water hoses also encourages water
conservation.  Most mills can reduce the volume of water to about
12,000 I/week  (3,000 gal), and this small volume can  be  handled
without discharge by containment, or land irrigation.
                              151

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For a plant producing 0.465 million sq m/year of hardwood plywood
the  veneer  dryer  wash water will be considerably less than the
flows discussed under veneer dryers  serving  a  9.3  million  sq
m/year  softwood  plant.   Control  technology  is the same i.e.,
containment, land irrigation, or evaporation.

PLYWOOD

Similar to the veneer manufacturing  subcategory,  treatment  and
control  technology  is not extensive in the plywood subcategory.
This  is  true  partly  because  water   requirements   for   the
manufacture  of  plywood are minimal.  In fact water is generated
only in the glue makeup and glue wash-up operations, and  in  the
veneer   drying  operations  where  they  occur  '-at  the  plywgod
manufacturing site.

Glue Lines

Current technology in the handling of glue wash  water  indicates
zero  discharge  to  navigable waters to be achievable throughout
the industry.  Recycle systems which eliminate discharge from the
glue lines are now in operation in about 60 percent of all  mills
visited during the course of the guidelines development study and
are  practicable  with  all  three major types of glue.  In 1968>
only one plywood mill had  a  glue  wash  water  recycle  system.
Currently  the  system  is  accepted  technology in the industry.
Nevertheless, there are still a  number  of  plywood  mills  that
discharge waste water from their glue operations.

A  plywood  mill  using  phenolic glue can reduce the waste water
flow from its glue operation to about 7,570  I/day   (about  2,000
gal/day),  without  altering  the  process,  by conserving water.
Urea formaldehyde glues do not require any more frequent  washing
than   do   phenolic  glues  and,  therefore,  can  be  similarly
controlled.  Protein glues, however,  normally  necessitate  more
frequent  cleaning  because  of shorter pot life of the glue.  In
order to reduce the flows from a mill that uses protein glue, in-
plant  modifications  in  addition  to  water  conservation   are
necessary.

Phenolic  glues  usually  require about 227 kg  (500 Ibs) of water
per batch, or 4.5 cu m/day (1200 gal/day).  Further reduction  of
waste  water  is  then necessary for all of the waste water to be
used in the  makeup  of  glue.   Table  26  indicates  that  most
southern  plywood  mills generate about twice as much waste water
from glue washing than can be used for glue mixing.

Various inplant operational and equipment  modifications  can  be
used to reduce glue washwater.  For example:

        (1)  Some plants wash glue spreaders several
             times a day, and some wash only once a
             week.  The less frequent washings can
             reduce the amount of water to between
                              152

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             10  and 30 percent of the original volume.

        (2)   The use of steam to clean the spreaders also
             reduces the water usage considerably., While
             steam cannot be used for some types of rub-
             ber coated roller spreaders commonly used with
             phenolic and urea glues, steam would be a
             practical modification for protein glue opera-
             tions which use steel rollers.  This is quite
             significant since the frequency of washing for
             protein glue lines cannot te reduced to the
             same extent as when synthetic resins are used.

        (3)   The use of high pressure water lines and noz-
             zles can reduce the amount of water used to
             30  percent of the original volume.

        (4)   The use of glue applicators which spray the glue
             rather than roll it onto the wood can reduce
             the volume of washwater, since these do not
             require washing as frequently as do the glue
             spreaders.

        (5)   The use of washwater for glue preparation and
             the reuse of remaining washwater for washing
             the glue system is a simple method of reducing
             waste water flows,  since a fraction of the
             washwater is used to prepare glue, a volume
             of fresh water can be added as final rinse in
             the washing of the glue spreaders.

These  modifications  can  be  used  in combination to completely
recycle the washwater  and  eliminate  discharge  from  the  glue
system.  A typical recycle system is shown in Figure 30.

There  has  been  no  difference in the quality of glue made with
fresh water and that made with washwater.   An  economic  benefit
has  been  established  by using glue waste water, because of the
fact that it contains glue and other  chemicals  such  as  sodium
hydroxide, as shown in Table 39.

Complete recycle systems are now in operation for phenolic, urea,
and  protein  glues.   Mills that use several types of glues must
have separate recycle systems to segregate  the  different  wash-
waters.   Attempts  at  mixing  washwater from different types of
glues have been unsuccessful.

In addition to washwater recycle, there are plants  that  contain
and/or evaporate glue washwater, spray the glue water on the bark
that  goes  into  the  boiler,  or  use  a  combination  of these
techniques.
                              153

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                                                          PLYWOOD PLANT BUILDING
        7-1/2 H.R MOTOR
        PROVIDING  CONTINUOUS

        AGITATION
TRASH
REMOVAL
CONVEYOR
BELT
CONCRETE
SETTLING
  TANK
                                                    2000 GALJ
                                                   COLLECTION
                                                     TANK
                                                 WATER
                                                 METERING
                                                 TANK
                                   GLUE
                                   MIXER
 MIX
HOLD
TANK 1


 Uo=!
                                                PUMP
                                                           PUMP
                                                                               GLUING  AREA
                                                                                GLUE
                                                                              SPREADERS
                                                                 CONCRETE DRAINAGE TROUGH IN  FLOOR
                   FIGURE 30
                       -  PLYWOOD PLANT WASH WATER  REUSE  SYSTEM

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en
en
                                                     TABLE 39

                                     THE ADHESIVE  MIXES  USED (CASCOPHEN 3566C)
                       Ingredients
  Mix 5 minutes

W-156V Resin

  Mix 2 minutes

50% Caustic Soda

  Mix 15 minutes

W-156V Resin

  Mix 5 minutes

         TOTAL

Resin Solids in Mix
                           Mix 1  (a
                                                     220
                                                     131
                                                   2,178
                                                   3,719

                                                      25.7%
Mix 2 (b
  220
   75
2,156.5
3,642.5

   25.7%
Mix 3 (c
Water

Phenofil
Wheat
Flour
700
350
140
701
350
140
700
350
140
  220
  100
2,163.5
3,673.5
   25.7%
                       a) Control mix  -  clean water  used for mix.
                       b) 20:1  dilution  of  Mix  1  used  for mix water - pH 11.5
                       c) 30:1  dilution  of  Mix  1  used  for mix water - pH 11.4

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HARDBOARD - DRY PROCESS

The small volumes of cprocess waste  water  discharged  from  dry
process  hardboard  mills and the variation of waste sources from
mill  to  mill  have  resulted  in  little  new  waste  treatment
technology  being  developed.   In  general,  because  the  small
volumes of waste water generated, the major  treatment  processes
have been limited to oil-water separation, waste retention ponds,
or perhaps spray irrigation.

The  major  waste water source in one particular mill may be non-
existent in  another  mill.   Inplant  modifications  to  reduce,
eliminate,  or  reuse  waste water can greatly affect total waste
water discharge from any  mill.   By  inplant  modifications  and
containment on site, the elimination of discharge can be achieved
throughout the dry process hardboard industry.


Log  Wash:   At  the  time of this study, only two mills reported
washing logs.  One mill which washes logs has zero  discharge  of
all  its  waste  through  impoundment  and  land irrigation.  The
second mill uses approximately 82 cu m/day  (21,600  gal/day)  for
log  washing  with  the wash water being discharged directly to a
stream without treatment.   Log  washwater  can  be  successfully
recycled  by settling with only a small percentage of blowdown to
remove accumulated solids.  The  blowdown  from  log  wash  water
recycle  systems  can  be  disposed  of  by  impounding  or  land
spreading.

Chip Wash;  At the time of this study, there were no dry  process
hardboard  mills  which  reported  washing chips, however several
have indicated plans to  install  chip  washing  in  the  future.
Until  such  time  as  chip  washers are installed and experience
gained, no  demonstrated  technology  is  available  in  the  dry
process  hardfcoard  industry  for treatment of this waste stream.
Predicted waste water discharges from a chip wash system are 18.9
to 37.8 cu m/day  (5,000 to 10,000  gal/day)  for  a  227  kkg/day
Dlant.
Resin System

Six  mills  out  of  the  total of 16 dry process hardboard mills
report no discharge from  their  resin  systems.   Several  other
mills  report  a  waste  discharge  of  less  than 750 I/day  (200
gal/day).  All hardboard mills use essentially the same types  of
resin (phenolic or urea formaldehyde).  Taking into consideration
that  several  mills  already  have  no  discharge of waste water
pollutants and that many plywood mills using the same resin  have
no  discharge  of  waste  water  pollutants from the resin  (glue)
system, dry process hardboard mills can employ similar  practices
and  procedures to to achieve no discharge of process waste water
pollutnts from their resin systems.
                              156

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Caul Wash:  Five (5)  mills report no caul wash  water  discharge.
Those  mills  reporting  discharges of caul washwater average 750
I/day (200 gal/day).   This low quality of  water  can  either  be
eliminated  or  neutralized,  as  necessary,  then disposed of by
impounding,  land  spreading,  or  disposal  of  by   alternative
methods*

Housekeeping;   Housekeeping  wash water is a miscellaneous waste
water flow which varies from mill to mill.  Several mills  report
no  housekeeping  washwater  as  all  cleaning inplant is done by
sweeping and vacuum cleaning.  At least two mills have waste flow
from their press pit which  usually  contains  oil.   This  waste
water  can  be  eliminated  by  preventing  condensate water from
entering the press pit and by  reducing  hydraulic  fluid  leaks.
Housekeeping  waste water can be either totally eliminated or, if
water is used, held on site by impounding and  spray  irrigation,
evaporation,  discharge  to a municipal system, or discharge to a
treatment system serving a timber processing complex.

Cooling Water:  cooling water is by far  the  major  waste  water
flow  from dry process hardboard mills.  Cooling wat,er is used in
such unit processes as refiner seal water  cooling  systems,  and
air  compressor cooling systems,  erator cooling systems.  Use of
cooling water varies widely but is usually less than 380 cu m/day
 (100,000 gal/day) Cooling water can be recycled  through  cooling
towers or cooling ponds.
                                                           \
Humidifier:   Hardboard  must  be  brought to a standarjd moisture
content after dry pressing.  This is done in a humidifier unit in
which a high moisture and temperature is maintained.  Nine  mills
report  no  water  discharge from humidification units, while one
mill reports a volume of less than 11 cu m/day   (3,000  gal/day).
It  has  been determined that humidifiers can be operated with ,no
discharge of waste water pollutants.

                                         s
Finishing;  All dry process hardboard mills report  no  discharge
from  finishing  operations.   Concern  was indicated by industry
with the potential of new technology  causing  waste  water  flow
from the finishing operation.  For example, air pollution control
regulations may make it necessary to switch from oil based paints
to  water  based  paints  in  which  case a potential waste water
source could exist.  At the present time there  is  no  discharge
from finishing operations.

Summary

The   water   pollution  resulting  from  dry  process  hardboard
manufacture  is  directly  related  to  waste  water   flow   and
concentration,  which,  in  turn,  is influenced by operation and
maintenance practices and situations in each mill.  The  decision
to wash logs or chips by a mill is a result of the effect of dirt
and  grit on inplant machinery.  High maintenance costs resulting
frem abrasion of refiner plates, and other equipment, may make it
                               157

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desirable to wash  logs  and  chips.   Quantities  of  extraneous
material  on  logs  depend  upon  harvesting  transportation  and
storage operations, and therefore, directly  affect  waste  water
flow and composition.

The  operation  and maintenance of the resin system affects waste
water flow.  Most hardboard  mills  and  numerous  plywood  mills
using  similar  resins are able to operate with no discharge from
their  resin  systems.   Modification  of  inplant  equipment  or
maintenance  procedures  should  eliminate  the resin system as a
source of waste water flow.

Caul washing, a min'or waste water source, is an  inplant  process
that  is  affected  by operation.  Cauls are soaked in tanks con-
taining  sodium  hydroxide  and  other  cleaning  agents.   After
soaking  they  are  rinsed  and put back into use.  The method of
operation of this cleaning system can greatly  reduce  the  water
usage  and  therefore  the quantities of water to be disposed of.
The resulting low volumes of water  (less than 750  I/day  or  200
gal/day) can be easily disposed of on-site.

Housekeeping  practices  vary  widely  from  mill  to  mill  with
resulting effects on waste water discharge.   Several  mills  are
able  to  perform  clean up operations without having waste water
being discharged.  Other mills use water for clean up  operations
because   of   the   ease   and  efficiency  of  water  cleaning.
Modification of  inplant  housekeeping  procedures  can  minimize
water  usage  with  resulting  elimination of discharge from this
source.

The press pit  (a sump under the press) can  collect  oil,  fiber,
and  condensate  water.   The method of clean up of the press pit
can significantly reduce waste from this process.   Modifications
can  be  made  to reduce or eliminate condensate water so that an
oil/water emulsion will not be formed.

HARDBOARD - WET PROCESS

As discussed in Section V, the volumes of waste  water  generated
in wet process hardboard manufacture is sufficient in volume that
the  waste water cannot be contained on site.  There is no single
scheme currently being used to treat waste water discharges  from
wet  process  hardboard  mills.   The major treatment and control
methods presently being used include water  recycle,  filtration,
sedimentation,  coagulation, evaporation and biological oxidation
processes such as lagoons, aerated lagoons, and activated  sludge
processes.

The  treatment  and control methods presently utilized in any one
mill have been influenced by pressure from  regulatory  agencies,
land  availability,  access  to  city  sewer,  individual company
approach to waste water control, and other factors.

Inplant Control Measures and Technology
                              158

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Raw Materials Handling;  There were no  mills  reporting  washing
logs, however, if logs were washed, a simple recirculation system
could be installed to eliminate discharge from this source.  This
recirculation  system  would  consist of a sedimentation basin or
pond to catch the washwater and allow the removal  of  settleable
solids.   Pumps  preceded  by screens would recirculate the water
for log washing.  Accumulated deposits in the sedimentation basin
or pond would be removed as needed and disposed of  as  landfill.
Chip  washing, if practiced, could be eliminated as a waste water
source in a similar manner.

Process Water:  The major source of waste water flow and  concen-
tration  comes from discharging the process water.  This includes
water  from  fiber  preparation,  mat  formation,  and   pressing
operations.   As  has  been  previously  discussed, the source of
organic material in the process water is  from  the  solution  of
wood  chemicals.   The  quantity of organics released is directly
dependent upon wood species, cooking time, pressure, temperature,
and degree and nature of refining.

It has been suggested that a decrease in BOD load can be made  by
reducing  the cooking or preheating temperature at the expense of
higher energy consumption in the refiners.  Little  research  has
been done in this area, however, only a portion of the BOD can be
eliminated in this manner.

Assuming  that chips contain 50 percent fiber and must be diluted
to 1.5 percent fiber prior to mat formation, for every kkg of dry
fiber processed, 60.5 cu m  (16,000 gal) of water  is  needed  for
dilution.  The obvious procedure to obtain this quantity of water
and  reduce  or eliminate the discharge of organic material is to
recycle a portion or all of the process water.

There are several limiting factors preventing  total  recycle  of
process water, including temperature, soluble organics, and build
up of suspended solids  (fines)*  Temperature of process water can
be  controlled by the installation of a heat exchanger.  At least
two mills report the use of shell and  tube  heat  exchangers  to
control process water temperature.

Soluble  organics  are  the  most difficult to control in the wet
process.  The explosion process utilized by  two  mills  produces
greater  quantities  of  soluble organics  (pollutants) than other
processes  because  of  the  higher  temperature  and   pressure.
Because of the large quantities of organic material released from
the  wood,  these  plants installed evaporation systems to reduce
the quantities of  organics  discharged  in  their  waste  water.
Figure  31 shows a schematic diagram of one of these systems.  In
this system countercurrent washers are used  to  remove  a  major
portion  of the organics from the fiber prior to dilution and mat
formation.  This waste stream passes through a darifier is  then
evaporated.   The concentrated organic stream from the evaporator
is sold as  cattle  feed  or  it  can  be  incinerated,  and  the
condensate is either reused as process makeup water or discharged
                              159

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                                                                                          TO ATMOSPHERE
                CHI
O)
O
WATER  IN


WATER OUT


CONCENTRATED
BY-PRODUCTS
                                                                        STOCK
                                            CLARIFIED
| CHEST) (MACHINE |

-------
as  a  waste water stream.  Process water from the felter and the
press pass through a clarifier to remove settleable solids.   All
solids  are  reused to make board, while the overflow is used for
fiber wash or dilution water.  The total BODS discharge from this
mill without  biological  treatment  is  only  3.25  kg/kkg  (6.5
Ib/ton) .

The thermal-mechanical pulping process releases less organics and
it   is   questionable  whether  or  not  process  water  soluble
concentrations can be increased to a high enough  level  to  make
evaporation  economical  without inplant modifications.  However,
at least one mill  in  Sweden  is  presently  evaporating  excess
process  water.   One possibility to decrease the volume of waste
water without increasing the concentration of soluble  substances
in  the  process water system at the same time is to arrange some
kind of prepressing  of  the  pulp  to  remove  the  concentrated
organics  before  they  enter  the refining and formation process
water stream.  An arrangement of this type is shown in Figure 32,
where a pre-press has been inserted after the  cyclone.   If  the
process water system is completely closed, all soluble substances
with  the  exception of those deposited in the hardboard would be
contained  in  the  waste  water  leaving  the  pre-press.    The
concentration  of  soluble substances in this waste water depends
on the amount of substances dissolved during the pre-heating,  on
the  volume  of waste water leaving the pre-press, and finally on
the efficiency of the pre-press, i.e.,  the  consistency  of  the
pulp  leaving  the press.  The efficiency of such a system can be
increased by installing two or three presses in series.  A system
of this  type  can  significantly  reduce  the  concentration  of
soluble   organics  in  the  process  water,  allowing  increased
recirculation rates.

Suspended Solids:  Suspended solids  within  the  process  stream
must  be  controlled  to limit the build up of fines which reduce
water drainage during mat formation and to  limit  the  suspended
solids  discharged  in the raw waste water.  If treatment methods
such as evaporation are used, the suspended solids concentrations
entering these processes must be  controlled.   Suspended  solids
removal  systems  are  usually  of  gravity  settling, screening,
filtration, or flotation.

Only 2 mills utilize sedimentation tanks for removal of suspended
solids in process water  prior  to  recycle,  and  both  use  the
explosion process.  These systems are shown in Figures 31 and 33.
Process  water  from  both  mat  formation  and final pressing is
passed through a clarifier and  reused  in  the  process.   Other
mills  utilize  gravity  separators  in  their  final waste water
treatment scheme, but do not recycle back to process.  In one  of
the  mills utilizing gravity separators to remove solids from the
process water, the settled solids are returned to the process and
become part of the board.  The other mill has not been able to do
this because of differences related to raw material.
                              161

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                        STEAM
01
no
                 (XX)
WATER IN



WAT ER  OUT



APPROXIMATE PERCENT FIBER

(CONSISTENCY IN PROCESS)
                                                                 STOC K
                                                                           WET FORMING
                                                                     WET
* J«5)
f
•
1

1
v

"' 1 -••-•»•- I I MAiniN-t I
(30) >
r\
k (1-5)

r
1
PROCESS
WATER
CHEST

(35)
KKtS3
^

'
y//s////y////y///////?//////y////y///tf^^^^
TO TREATMENT
                         FIGURE 32 - TYPICAL WET-PROCESS HARDBOARD MILL WITH PRE-PRESS

-------
                                                                        TO ATMOSPHERE
CHIPS^'GUN
       WATER IN
       WATER OUT

       CONCENTRATED
       BY-PRODUCTS
          FIGURE 33  -  INPLANT TREATMENT AND CONTROL TECHNIQUES AT  MILL NO. 3

-------
Filters can  accomplish  the  same  liquid  solid  separation  as
gravity separation.  The efficiency of such filters varies widely
depending  upon  flow rates, suspended solids concentrations, and
types and  sizes  of  solids.   Representative  data  for  filter
efficiency may be found in Table 40.

One  system  utilized  for  controlling  suspended  solids  is  a
patented process developed in Finland at the Savo Oy Mill.   This
system  is  a chemical treatment system followed by sedimentation
and/or flotation.  The chemical treatment includes adjustment  of
the  pH,  addition  of  chemicals  for  coagulation,  followed by
removal of suspended solids  and  some  dissolved  and  colloidal
solids^

There are 2 mills in the U.S. presently using this system to some
degree.   Typical  data  from  the  Savo system from one of these
mills is shown below:

COD
Total suspended solids
Total dissolved solids
Soluble organics
Volatile suspended solids
Influent
(mq/1)
7775
750
5525
4285
740
Effluent
(ma/1)
4745
48
4788
3362
46
Percent
Reduction
39
94
13
22
94
An advantage reported from the use of the Savo'system is that all
sludge from the system can be reused in the board.  One mill  has
been  able  to  reduce  its waste water flow to 2.3 cu m/ton (611
gal) and BOD discharge to 8.5 kg/kkg (17 Ib/ton).  This rate  and
concentration is the result of inplant modifications and does not
include  end  of  line  treatment.   Figure  34 shows a schematic
diagram of this process.

End of Line Waste water Treatment

The existing end  of  line  waste  treatment  facilities  consist
primarily   of  screening  followed  by  primary  and  biological
treatments.  All of  the  wet  process  hardboard  mills  utilize
primary  settling  basins either within the process or as part of
their final waste treatment facilities.  In order to protect  the
primary  settling units from sludge loading and to remove as much
fiber as possible, screens are  generally  placed  ahead  of  the
primary  units.   Fiber  removed  by  screening is disposed of by
landfill or returned to process.

Three of nine wet process mills were either sampled or  the  mill
reported  treatment efficiencies across their primary clarifiers.
This data is shown in  Table  41.   Although  this  data  may  be
typical  of the treatment efficiency that existing facilities are
achieving, it is not representative of the efficiency that can be
obtained through proper design and operation.   The  three  mills
                              164

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                      TABLE  40

REPRESENTATIVE PROCESS WATER FILTER EFFICIENCIES

                 	Suspended Solids  (mg/1)	
Mill	.	Before Filter	After Filter

 0                1000 - 3500         80 - 250
 P                 170 - 1000         30 - 150
 Q                1000 T 1300        280 - 330
 R                 230 - 620          90 - 145
                         165

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          STEAM
CHIPS
       WATER IN
       WATER OUT
                                   TO
                                   .ATMOSPHERE
        DREH EATER— REFINER
                                                     WET FORMING
                                                       MACHINE
FIBER
TO
PROCESS
                                                      PROCESS
                                                      WATER
                                                      CHEST
                                WET
                                PRESS
                                                                            TO
                                                                            FINISHING
i
^
S AVO



	 1

                                    DISCHARGE
         FIGURE 34 - TYPICAL  WET-PROCESS HARDBOARD MILL WITH  SAVO SYSTEM

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                                          TABLE 41

                             PRIMARY  SETTLING TANK  EFFICIENCY
           BOD IN
Mill
                  BOD Out
mg/1   k/kkg    mg/1   k/kkg
Percent
Removal
   SS In
mg_/l   k/kkg
   SS Out
mg/1   k/kkg
Percent
Removal
        2400   28.5

        3500   32

        6000   42.2
                2400   28.5

                3300   30.5

                3900   28
   0

   5

  35
1650    19

 430     4

1440    10
 178    2

 154    1.4

 450    3.25
  89

  69

  68

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listed1 in Table 41 utilized settling ppnds as primary clarifiers.
These  ponds are allowed to fill with, solids before being dredged
for  solids  'removal.   Accumulated  solids   undergo   anaerobic
decomposition  causing  an  increase in BOD5 and suspended solids
(SS) in the effluent.

A properly designed clarifier with a mechanical sludge  collector
and   continuous   sludge  removal  can  be  expected  to  obtain
approximately 75 to 90 percent SS reinoval and 10  to  30  percent
BODIJ removal.
The pH of wet process waste water varies from 4.0 to 5.0.  ^?he pH
must  be  adjusted  to near 7.0 to obtain satisfactory biological
degradation.  The pH may be adjusted by the addition of  lime  or.
sodium hydroxide.

wet  process  hardboard mill waste water is deficient in nitrogen
and phosphorus.  These nutrients must be added in  some  form  to
obtain  rapid  biological  degradation  of  the  waste.  The most
commonly used source of nitrogen is anhydrous  ammonia,  and  the
most commonly use£ source of phosphorus is phosphoric acid-

Existing biological treatment systems consist of lagoons, aerated
lagoons,  activated  sludge, or a combination of these.  The type
of system presently used at each mill is shown below:

Mill No.                End^ Of Line Treatment System


  1          Primary settling pond - aerated lagoon -
             secondary settling pond.
  2          Primary settling pond - aerated lagoon -
             secondary settling pond.
  3          Primary clarifier - activated sludge -
             aerated lagoon
  4          Primary settling pond - activated sludge -
             aerated lagoon
  5          Primary settling pond - activated sludge -
             lagoon or spray irrigation.
  6          Primary settling pond.
  7          NO treatment.
  8          (No^ treatment.
  9          Aerated lagoon.
Table 42 shows the treatment efficiency of the five   mills  whicli
presently  have  bioligical  treatment systems in operation.   The
values shown are average values and do not define the  variations
in  effluent  that  can  be expected  from biological  systems.   It
should be noted that the values shown for mills  No.   1,2,   and  5
include  the  efficiency  of the  primary settling units while  for
mills No. 3 and 4 the efficiency  is across  the  biological unit
alone.
                               168

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                TABLE  42
TREATMENT EFFICIENCY OF BIOLOGICAL SYSTEMS

Mill No.
*+i
*+2
*3
*4
*+5
**+!
**+2
*3
*4
*5


Influent
33
50
23
28.5
32
720
1310
1800
2400
3500

BOD, kg/kkg
Effluent
7
15
0.6
6.45
1.55
151
393
54
552
175


Percent
Removal
79
70
97
77
95
79
70
97
77
95


Influent
10
_-
1.4
0.7
1.4
220
—
114
60
151
\
SS, kg/kkg
Effluent
9
--
3.6
4.2
3.6
bb, mg/x 	
198
— —
295
360
388


Percent
Removal
10
--
0
0
L,^
10
_»
0
0
0






— *. f




   + Includes efficiency of primary settling
  ** Aerated lagoons
   * Activated sludge

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Mills  No.  1   and  2  utilize! Werated lagoons.  Their treatment
efficiencies for BOD removal hnvj averaged  70  and  79  percent,
respectively.    Mills  3,  4, atra 5 utilize some variation of the
activated sludge process and their average efficiencies  for  BOD
removal  are  ^7,77,  and  95 percent, respectively.  Mill No. 4,
whose activated sludge system averages only 77 percent efficiency
for BOD removal is actually not operated as an  activated  sludge
system  as theare is no sludge wastes from the system.  Therefore,
the system is more representative of an aerated lagoon system.

The efficiency  of solids removal across the biological system for
all mills is essentially zero.  There  are  several  reasons  for
this.   Biological  solids  produced  in  waste treatment systems
treating hardfcoard  waste  water  are  difficult  to  settle  and
dewater.   There  is  presently  no  economical  method  that  is
satisfactory for  handling  waste  activated  sludge  from  these
biological  systems.   one  mill attempts to utilize a centrifuge
for sludge thickening prior to incineration, however, the  system
is highly variable in its efficiency and 'frequently excess sludge
has to  be hauled by tank trucks to a land spreading area.

Several  mills  in the U.S. and Europe have put excess sludge back
into  the  process water to become part of the board.  The quantity
of sludge which can be reclaimed in this manner is variable  from
mill  to  mill   depending upon a variety of factors.  It is known
that  the  addition of sludge to  the  board  increases  the  water
absorption,  reduces the drainage rates, and make it necessary to
add  additional  chemicals to compensate for the sludge addition.

At least  one mill (mill No. 5)  is disposing of its  waste  sludge
by   spray  irrigation.   Waste sludge is pumped to an aerobic di-
gester, then the digested sludge is  pumped  to  a  nearby  spray
irrigation   field.   Land  irrigation or sludge lagooning has the
advantage of making it unnecessary to dewater the sludge prior to
 disposal.

The  difficulty in handling waste sludge from the activated sludge
 treatment of wet process hardboard waste water leads to  a  build
 up  of  solids  within  the  system with a resulting discharge of
 solids in the effluent.   Weather  conditions  (temperature)   are
 also  reported  to  have  an  effect  on  the  settling  rate  of
 biological solids in both aerated lagoon systems  and  the  acti-
 vated sludge system.

 Figures  35,  36,  and 37 show the variations in effluent BOD and
 suspended solids for mills No. 2, 3, and 4, respectively.  Values
 shown are monthly averages and do not necessarily indicate a  di-
 rect   relationship   between   suspended   solids  and  seasonal
 temperature variations.  The main information presented by  these
 graphs  is that for either the aerated lagoon or activated sludge
 average, suspended solids in the effluent can be expected  to  be
 250 mg/1.
                               170

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1/72   2/72   3/72   4/72   5/72   6/72   7/72   8/72    9/72   tO/72   11/72   12/72   1/73
          FIGURE 35 - VARIATION OF EFFLUENT BOD AND SUSPENDED SOLIDS
                      AS  A FUNCTION OF  TIME FOR MILL NO.  2

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                                                                                           BOD
ro
1/72   2/72  3/72  4/72   5/72   6/72   7/72   8/72   9/72  10/72   11/72
                                                                                          12/72
                             FIGURE 36 - VARIATION OF EFFLUENT BOD  AND SUSPENDED  SOLIDS
                                         AS A  FUNCTION OF TIME FOR  MILL NO. 3

-------
OJ
                 1/72
2/72
3/72
4/72
5/72
6/72
7/72
8/72
9/72
10/72
11/72
                            FIGURE 37 - VARIATION OF EFFLUENT  BOD AND SUSPENDED  SOLIDS
                                        AS A  FUNCTION OF TIME  FOR MILL NO. 4

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Table 43 shows an example of an aerated stabilization basin  (ASB)
or aerated lagoon performance related to tempe rat tire.  This table
is  for  a  biological system treating paperboard waste.  Similar
effects are experienced in the wet  process  hardboard  industry.
The  main difference, however, is that the quantity of solids can
be expected to be several times greater.

Summary

Water  Reuse;   The  9  wet  process  hardboard  mills  presently
practice  considerable  recycle  of  waste  water.  These systems
include:

(1)   process water recycle with  blowdown  to  control  suspended
solids and dissolved organics.  This blowdown may occur in a pre-
press,  from  the  wet  or  hot  press, or from the process water
chest.  (2)   Process water recycle through  a  primary  clarifier
with  blowdown  of some clarifier effluent and recycle of some or
all sludge to  the  stock  chest.    (3)   Process  water  recycle
through  a  primary  clarifier with falowdown being evaporated and
some evaporator condensate being utilized  for  makeup.   In  the
explosion  process  all  fiber  washwater is discharged through  a
primary clarifier  prior  to  evaporation.    (4)   Process  water
recycle   with  blowdown  passing  through  chemical  coagulation
system.  Part of coagulated waste recycled back  to  process  and
all sludge returned to stock chest.


Waste water Treatment:  End of pipe treatment technol-
ogy presently consists of one or more of the following practices:

                (1)  Screening
                (2)  Primary clarification
                    a.  settling ponds
                    b.  mechanical clarifiers
                (3)  pH control
                (4)  Nutrient addition
                (5)  Aerated lagoons
                (6)  Activated sludge process
                (7)  Oxidation lagoons

Sludge Handling:  Systems utilized for disposal of waste
sludge include:

                (1)  Reuse in manufacture of hardboard
                (2)  Landfill
                (3)  Spray irrigation
                (4)  Incineration
                              174

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                          TABLE  43

EXAMPLE OF AN ASB SYSTEM PERFORMANCE  RELATED TO TEMPERATURE



                      PAPERBOARD*
Average
Monthly
Temperature
(°C)
21
21
19
17
17
11
7
5
5
3
Effluent
BODS
(mg/1)
11
17
22
17
11
20
40
29
38
42
Cone .
SS
(mR/1)
22
21
23
17
16
29
56
61
31
42
                 *  Includes  long-term
                    settling
                                175

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WOOD PRESERVING

The  technological  base for waste control in the wood preserving
industry is generally quite weak by comparison  with  most  other
industrial   subcategories.    Relatively   few   companies  have
employees with the engineering and other technical skills  needed
to utilize effectively current or potential developments in waste
treatment  and  management,  or  to adopt processing methods that
would minimize waste loads.   Engineering  services  required  by
individual  plants  are  most  commonly  performed  by consulting
firms.  This situation is ameliorated somewhat  by  the  American
Wood-Preservers'   Association  through  the  activities  of  its
technical committees and publication of its Proceedings, both  of
which  serve to keep its members advised of current developments.
Membership in the association represents plants that account  for
an estimated 90 percent of the total production of the industry.


The  comments  and  data  which  follow  summarize  the status of
pollution control activities in the wood preserving industry,  as
revealed  by  a  recent  <1973) survey by Thompson of 377 plants.
The data are based on the results on a questionaire  survey  from
207 plants.

Disposition of Waste water

The  approach  to  the  pollution  problem taken by many treating
plants is to store their waste water on company  property   (Table
44).   This  is  by far the most popular method of handling waste
water,  accounting  for  42  percent  of  the  plants  reporting.
Seventeen  percent  are still releasing their waste water with no
treatment, while 14 percent of  the  plants  are  discharging  to
sanitary  sewer  systems.   Of  the  latter group, 63 percent are
discharging raw waste to sewers, while 37 percent are giving  the
waste a partial treatment before releasing it.  Only 9 percent of
the  207  plants  responding  to  the survey presently are giving
their  waste  the  equivalent  of  secondary   treatment   before
releasing it.  Eighteen percent either have no waste water or are
disposing  of  it  by  special  methods  such  as  evaporation or
incineration.

There are no unusual trends when the data on methods of  disposal
of  waste  water were broken down by region  (Table 45).  However,
it is of interest to note that a high proportion of the plants in
the West dispose of their waste by special methods,  or  have  no
waste stream.

Compliance With Standards

Sixty  percent of the plants surveyed in 1973 indicated that they
currently meet state and federal water pollution standards  (Table
46).  Twenty-five percent  stated that  they  do  not  meet  these
standards  and  15 percent do  not know whether they do or not.   A
higher portion of plants in the West and Southwest currently meet
                              176

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TABLE 44  METHOD  OF  DISPOSAL OF WASTEWATER  BY  WOOD
          PRESERVING PLANTS IN THE UNITED STATES
Disposal Method
Release - No Treatment
Store in Ponds
To Sewer - Untreated
To Sewer - Partial Treatment
Secondary Treatment
Other*
*No wastewater, incineration
Number
of
Plants
35
86
19
11
18
38.
, etc.
Percent
of
Plants
17
42
9
5
9
18

  TABLE 45   METHOD OF DISPOSAL OF WOOD  PRESERVING
                     WASTEWATER BY REGION
Region
Southeast
Southwest
Atlantic Coast
Lake and Northeast
Release
Untreated
13
5
9
2
Store
29
20
10
17
Sewer
12
6
4
6
Treat
5
4
4
5
Other
17
5
4
2
                              177

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    TABLE 46. COMPLIANCE WITH STATE AND FEDERAL WATER STANDARDS
         AMONG WOOD PRESERVING PLANTS IN THE UNITED STATES
Compliance
Yes
Don't Know
No
Number
of
Plants
126
29*
52
Percent
of
Plants
60
15
25
*Includes Non-Responses
     TABLE 47. PLANS OF WOOD PRESERVING PLANTS  NOT  IN  COMPLIANCE
                WITH WATER STANDARDS  ~ UNITED  STATES
                  Plan
Number
  of
Plants
None
Discharge To Sewer - Raw
Discharge to Sewer - ui I  Removal
Discharge To Sewer - Oil  + Phenol  Removal
Construct On-Site Treating System
Other
     TOTAL
  29
   5
   6
   4
  25
  IL
  81
                         178

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standards than in other regions of  the  country.   However,  the
differences  among regions are not great, ranging from 57 percent
of the plants in the Atlantic Coast region to 73 percent  in  the
West.

Table  47  gives a breakdown of what the plants that did not meet
the 1973 standards  plan  to  do  with  the  their  waste  water.
Nationally,  roughly  onethird  of the plants have made no plans.
Most of the remainder plan either to construct on-site  treatment
facilities  for their waste water  (31 percent) or discharge it to
sewer systems  (19 percent).  Twelve of  the  81  plants  involved
indicated  that they would dispose of their waste by other means.
Incineration and evaporation were  two  of  the  "other"  methods
mentioned.

Over  a  third of the plants not meeting standards are located in
the southeast.  Most of these plants are planning to treat  their
waste  on  site  or  discharge it to a sewer system.  Half of the
plants in the West and Lake and Northeast states  indicated  that
they have made no plans to meet applicable standards.

Of  the  plants  that have installed or plan to install secondary
treating facilities, 70 percent will use either  oxidation  ponds
or  soil  percolation   (Table  48).   Only  14  plants   (about 15
percent) have elected  to  use  trickling  filters  or  activated
sludge.   The  choices  of  the various methods of treatment were
generally uniform among regions, with no single region showing  a
strong preference of one method over another  (Table 4.9) .

Plant Sanitation

Plant sanitation covers those aspects of plant housekeeping which
reduce   or   eliminate  the  incidence  of  water  contamination
resulting  from  equipment  and  plumbing  leaks,   spillage   of
preservative,  and  other  similar sources.  Lack of attention to
these sources of pollution is a serious problem  at  many  plants
that  will  require remedial action.  Its origin lies in the lack
of  appreciation  of  the  fact  that  even   small   losses   of
preservative   can  largely  negate  waste  management  practices
directed toward collecting and treating process water.
                              179

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       TABLE 48  TYPE  OF  SECONDARY WASTEWATER  TREATING FACILITIES
               INSTALLED  OR PLANNED BY WOOD  PRESERVING PLANTS  IN U.S.
                                                                   Number
                                                                     of
                                                                   Plants
      Oxidation Pond

      Trickling Filter

      Activated Sludge

      Soil Percolation

      Chemical Oxidation

      Other (incineration)
                                               TOTAL
31

 8

 6

31

 3

10
89
      TABLE  49   TYPE OF SECONDARY  WASTEWATER TREATING FACILITIES INSTALLED
                      OR PLANNED  BY WOOD PRESERVING  PLANTS BY REGION
Treatment
Oxidation Pond
Trickling Filter
Activated Sludge
Soil Percolation
Chemical Oxidation
Other
SE
12
3
1
12
1
0
sw
9
3
2
2
0
4
AC
3
0
1
9
1
0
w
2
1
1
2
1
6
L&NE
5
1
1
6
0
0
SE -  Southeast
SW -  Southwest
AC -  Atlantic Coast
W - Western
L - Lake and Northeast
                                  180

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Preservative Loss From Retorts
Areas under and in the immediate vicinity of retorts are the most
important from the standpoint of plant sanitation.  The camber in
some retorts prevents the complete drainage of preservative  from
the  retort  upon completion of a charge.  Consequently, when the
retort door is  opened  to  remove  the  charge,  a  quantity  of
preservative  drains into pipe trenches or sumps under the retort
where it becomes contaminated with dirt, storm water,  and  other
types  of  preservatives.   Most  plants process the preservative
through oil separators and  thereby  recover  most  of  it.   The
better  managed  and  equipped plants collect it in troughs as it
drains from the retorts and transfer it  to  underground  storage
tanks.

Losses  of  preservative  in  the  vicinity  of the retort are of
particular  importance  in  salt-type  treatments  because   they
represent  the  major  source of pollution.  Many such plants are
equipped to collect preservative  spillage  and  wash  water  and
reuse it as make-up water for fresh treating solutions.


Storm Water

Storm water becomes contaminated as it flows over areas saturated
with  preservative  from  spills  and leaks.  Areas of particular
concern  are  those  around  and  in  the  vicinity  of  treating
cylinders,  storage  tanks,  and separators.  Because these areas
are usually not large, it is practical to reduce  the  volume  of
storm  water  that  must  be  treated  by  constructing dikes and
drainage ditches around the areas to prevent uncontaminated water
from flowing across them.

Preservative accumulation in the  soil  where  treated  stock  is
stored,  although  unavoidable,  is  another  potential source of
contaminated storm water.   Storage  yards  frequently  encompass
large areas.

Equipment Leaks
Preservative  losses  from  pipes  and  pumps  contribute  to the
pollution problem at many plants.  The early detection  of  leaks
from  these  sources  can  best  be ; accomplished by periodic and
systematic checks of all  pumps  and  plumbing  employed  in  the
transfer of preservatives.

Treatment and Control Technology

Waste  water  treating  facilities have been installed and are in
operation at only about 9 percent of the estimated 390 plants  in
the  U.S.    (Table  44).   Most  of these facilities have been in
                              181

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operation for only a relatively short period of time.  It follows
that both experience in the treatment of  waste  water  from  the
wood  preserving  industry  and  the  backlog  of  data  on  such
operations is limited.  This  problem  is  lessened  somewhat  by
studies  and  field  experience  in  the  treatment  of petroleum
wastes.   Data  from  this  industry  are   frequently   directly
applicable  to  the  wood  preserving  industry  because  of  the
similarity of the effluents  involved,  particularly  as  regards
phenol  content,  oil  content  and  other parameters.  Likewise,
within the past three years laboratory  and  pilot-plant  studies
have  supplied  useful  information on the treatment of effluents
from wood preserving operations.  Review  of  these  sources,  as
well  as  information  obtained  from  visits  to and analyses of
effluent samples from wood preserving plants that have  effective
waste  treatment  and  management  programs, provided the data on
which this section is based.

Primary Treatments

Primary treatments for creosote  and  pentachlorophenol-petroleum
waste  waters  usually  include  flocculation  and sedimentation.
This process, as currently practiced at a number  of  plants,  is
normally  carried  out  for  one  of two purposes:   (1) to remove
emulsified oils and other oxygendemanding substances  preparatory
to  secondary treatment, and  (2) to render waste water acceptable
to municipal authorities prior  to  releasing  it  into  sanitary
sewers.   A  few  plants discharging their waste into city sewers
apply primary  treatments  to  reduce  sewer  charges  levied  by
municipal  authorities,  rather  than  to  meet specific influent
limitations.

One of the principal benefits of primary treatments of oily waste
water is the reduction of the oil content of the waste water to a
level compatible with the  secondary  treating  process  that  is
employed.  This is particularly important with those waste waters
containing  emulsified  oils, which normally cannot be removed by
mechanical means.  Flocculation treatments employing  a  suitable
polyelectrplyte  are  quite  effective  in breaking emulsions and
precipitating the oil.  Reductions in oil content on the order of
95 percent are not unusual.  Where the oil content of waste water
is  not  a  serious  problem,  however,  flocculation  treatments
preparatory  to  secondary  treatment  may not be necessary.  The
decision in this regard must be based on  the  relative  cost  of
such  treatments  and  that  of  providing  sufficient  secondary
treating capacity to accommodate the additional COD loading  that
would  normally  be removed during primary treatment of the waste
water.

Primary  treatments  of   waste   waters   containing   salt-type
preservatives  and  fire  retardants  serve  to precipitate heavy
metals and thus make the waste amenable to biological treatment.

Waste Waters Containing Entrained Oils - It is the  intermingling
of  the oils and water from the treating cycle and the condensate
                              182

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I
           from  conditioning  operations that  is responsible  for most of  the
           waste water  pollution  in the  industry.  Oils account  for most of
           the oxygen  demand  of  the  waste  water,  serve  as  carriers  for
           concentrations  of pentachlorophenol   far   in  excess of  those
           attainable  in oil-free  water,  and  create emulsion problems.

           Recovery Of Free Oils - Most wood   preserving   plants   have   oil-
           recovery systems for  reclaiming  a  high percentage of the oil  that
           may   become entrained in water during  treating  operations.  Apart
           from  environmental considerations, this practice  is   and  always
           has   been  done for  economic  reasons:  it is less expensive to
           recover  and reuse  this  oil  than  to buy new  oil.   With  the passage
           of the Federal Water  Pollution Control Act  of  1965  and subsequent
           amendments, the contribution of  non-recovered  oils  to  the cost of
           treating waste  water  has  become  an important  consideration.
           Within  the  past  5 years many plants  have  added  new oil-recovery
           systems  or  revamped existing ones.

           Free   oils  are recovered  from  waste water by   gravity-type
           separators.   Various designs  are  used. The most common ones are
           patterned after the separator  developed by  the American Petroleum
           Institute.  These  are equipped to  recover oils both lighter  and
           heavier   than water.  Basically  they consist of a horizontal  tank
           divided  into  three or more  compartments by   strategically   placed
           baffles  which decrease  turbulence.  Heavy oils sink to the bottom
           where they  are  removed   by  a pump to a  dehydrator, and thence
           transferred to storage. Floating  oils are  removed  by  a  skimmer.
           For   pentachlorophenol-petroleum  solutions,  a  simple tank or
           series of tanks with  provisions  for  drawing  off  the oil   that
           collects at  the top  and the water from the bottom  is  all that is
           required.  Good practice dictates  the  installation of  separate
           oil   removal  systems  for each  preservative. However,  many  plants
           are  not  so  equipped.

           A few plants  have  installed  air-flotation   equipment   to   effect
           oil-water  separation.  In  these units, all oil is  brought  to the
           surface  of  the water  by bubbles  created by  saturating   a  portion
           of  the   waste  water with  air under pressure  and releasing  it at
           the  bottom  of the  flotation chamber.   The oil  is  removed  at the
           surface  by  a  skimming device.  Mechanical oil  scavengers  are  also
           sometimes used to  remove  surface oils.

           The   percentage of entrained  oils  removed by oil-water separation
           equipment varies widely,  depending in part  upon  whether  or not
           the   oil  is   in  a free  or emulsified form.  Data  on  the percent
           efficiencies  of several oil-separation processes,  including the
           API   separator, are given  in Table 50. These  data  are based upon
           the   treatment  of  petroleum  refinery waste water,  but  are
           applicable  to  other  oily wastes.   Separator  efficiency is of
           course a function  of  detention time.   The  effect  of this  variable
           on oil removal is  shown in  Figure 38.

           Only free oils are removed  in  conventional  oil-water  separators.
           However,  emulsions  are   broken  by rotary vacuum filters  and by
                                         183

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TABLE 50  EFFICIENCIES OF OIL SEPARATION PROCESSES

API Separator
Air Flotation without
Chemicals
Air Flotation with
Chemicals
Chemical Coagulation and
Sedimentation
TABLE 51 EFFECT OF
CONTENT OF
Lime
(Sin /I) pH
0.0 5.3
0.25 6.8
0.50 7.9
0.75 9.7
1.00 10.5
1.25 11.4
1.50 11.8
Source Of Percent Removal
Influent Free Oils Emulsified Oils
Raw Waste 60-99 ^ Not applicable
API 70 - 95 10 - 40
Effluent
API 75 - 95 50 - 90
Effluent
API 60 - 95 50 - 90
Effluent
LIME FLOCCULATION ON COD AND PHENOL
TREATING-PLANT EFFLUENT
COD
Cone. Percent Phenol
(mg/1) Removal (mg/1)
11,800 -- 83
9,700 23 81
7,060 39 72
5,230 56 78
5,270 55 80
5,210 56 84
5,210 56 83
                        184

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            AVERAGE TEMPERATURE-38°C
        INITIAL OIL CONCENTRATION-45P.P.M.14P.P.M.
   0     40     80     120   160
    SEPARATION  TIME  IN  MINUTES
                    200
FIGURE 38
EFFECT OF DETENTION TIME  ON OIL
REMOVAL BY GRAVITY SEPARATION
               185

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centrifuges, both of which have been tested  on  wood  preserving
waste  water  at  a  few  plants  in  the  South-   Waste  waters
containing emulsified oils frequently have oil contents in excess
of 100Q mg/1 after passing through gravity-type separators.  Oils
in this form normally  must  be  removed  by  primary  treatments
invoIving flocculation.

The  formation  of  oil-water  emulsions  is a particular problem
where conventional steam  conditioning  is  used  and  apparently
results  from  agitation  of  retort condensate as it is expelled
from  the  retort  through  a  steam  trap.   Thompson   analyzed
condensate samples collected alternately from a hole drilled near
the  bottom of a retort and from a pipe leading from the trap and
found that only those samples that had passed  through  the  trap
contained   emulsified   oils.    Some   plants   treating   with
pentachlorophenol-petroleum solutions have  greatly  reduced  the
problems  of  emulsion  by replacing high-speed pumps involved in
preservative transfer with low-speed, high-volume models.

Breaking  Of  Oil-Water  Emulsions  -  Emulsions  may  be  broken
chemically,   physically,   or  electrically.   Chemical  methods
involving flocculation and.  sedimentation  are  the  most  widely
used,  generally  are the least expensive, and are effective with
effluents from wood preserving plants.  For  these  reasons,  the
discussion   below  is  directed  towards,  chemical  methods  of
breaking emulsions.

Chemicals that have been used to break oil-water emulsions either
in  the  laboratory  or  field,  include   metallic   hydroxides,
principally  lime, ferric chloride and other salts of iron, alum,
bentonite clay, and various types of polyelectrolytes.  The  same
material  or  combination of materials does not work equally well
with waste waters from all plants (Table 29, Section V).  COD and
BOD reductions of up to 83 percent have been achieved in creosote
waste water by using a single cationic polymer at a  rate  of  40
mg/1.   Similar  results  were  observed at a plant treating with
both creosote and pentachlorophenol that  flocculated  its  waste
prior to routing it to a sanitary sewer.

Oil  reductions  in  refinery waste water of more than 95 percent
were obtained by using both anionic and cationic polyelectrolytes
in combination with bentonite clay. . There was no difference  be~
tween  the  two  types  of  polymers  in  the  results  obtained.
However, only cationic polyelectrolytes broke oil^water emulsions
from wood preserving plants in work reported in  1971.   Aluminum
chloride,   alum,  activated-silica,  clay  and  lime  have  been
employed with refinery wastes, and reductions in  BOD,  COD,  and
oil  content  on  the order of 50 percent were reported from this
treatment.

Ferric chloride has been found to be  an  effective  flocculating
agent  for  both  creosote  and  pentachlorophenol  waste waters.
However, floe formation  occurred  only  within  very  narrow  pH
                              186

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lirrtits.   This  feature  would  pose  serious  problems  in field
applications of this chemical.

Much of the research work on flocculating wood  preserving  waste
waters  has  involved  the  use  of  lime  either  singly  or  in
combination with a polyelectrolyte.  Thompson and  Dust  reported
that  the  optimum dosage of lime, as judged from COD reductions,
varied  from  0.75  to  2.0  g/1,  depending  upon  waste   water
characteristics.   Percent  reduction in this parameter increased
with increasing dosage up to a maximum, and then  was  unaffected
by  further lime additions  (Table 51).  Phenol content, exclusive
of pentachlorophenol, was not decreased by  flocculation  of  the
waste water.  However, pentachlorophenol was regularly reduced to
a  concentration of about 15 mg/1 in waste waters containing this
chemical.    It   was   surmised   from    this    result    that
pentachlorophenol,  unlike other phenolic compounds, is primarily
associated with the oil  phase  in  oil-water  emulsions  and  is
precipitated  with  the  oils  when  the emulsion is broken.  The
residual concentration  of  pentachlorophenol  remaining  in  the
filtrate   was  reported  by  Thompson  and  Dust  to  correspond
approximately to  the  solubility  of  this  chemical  in  water.
Typical data showing the reduction of pentachlorophenol resulting
from lime additions to a waste water are shown below:

                                         Residual PCP
             Lime Dosage                 Concentration
              (mq/11                          (mq/1)

                0                            150

                1.0                           45

                1.5                           25

                2.0                           17

Lime,  in dosages of 2.0 g/1, has been shown to obtain reductions
in COD of up to 70 percent in a creosote  waste  water.   Similar
results  have  been  achieved  with alum, and both chemicals have
been used successfully to treat creosote and  vapor-drying  waste
water  previously  de-emulsified  with  sulfuric  acid.  Lime and
caustic soda have been reported to be effective  in  flocculating
oily  waste water after treatment with polyelectrolytes failed to
produce a floe.

Among numerous polyelectrolytes tested by Thompson and Dust rela-
tively few were found that in the absence of lima were  effective
with wood preserving waste water.  The primary contributions that
many  of the test materials made to the flocculation process were
the agglomeration of minute floe particles, which promoted  rapid
settling,  and  reduction  in  sludge volume.  Only a few of them
were effective in initiating floe formation in samples  of  waste
water  from 20 plants, and none increased COD removal beyond that
obtained with  lime  alone.   The  few  that  were  effective  in
                               187

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listing  of  the  principal  water-soluble preservatives and fire
retardants currently  marketed  in  the  U.S.,  and  the  harmful
constituents in each, is given in Table 52.

The   procedure  used  to  precipitate  heavy  metals  from  wood
preserving  effluents  was  adopted   from   the   electroplating
industry.   Dodge  and  Reams compiled a bibliography of over 700
references dealing with the processing and disposal of waste from
this industry, and  it  is  been  estimated  that  50  additional
articles  on  the subject have been published annually since this
bibliography first appeared.  A detailed treatment of the subject
has been prepared by Bliss.  The basic procedure followed,  while
modified  to reflect the specific preservative salts involved, is
described below.

With the exception of boron, hexavalent chromium is the only  ion
shown  in  Table 52 which will not precipitate from solution when
the pH of the waste water is raised to 7 or 8 with  lime.   Since
trivalent  chromium  will  precipitate  from  neutral or slightly
alkaline solutions, the  first  step  in  treating  waste  waters
containing  this metal is to reduce it from the hexavalent to the
trivalent form.  The use of sulfur dioxide for this  purpose  has
been  reported  on  in  detail  by  Chamberlin and Day.  Chromium
reduction proceeds most rapidly in acid solution.  Therefore, the
waste water is acidified with sulfuric acid to a pH of 4 or  less
before  introducing the sulfur dioxide.  The latter chemical will
itself lower the  pH  to  the  desired  level,  but  it  is  less
expensive to use the acid.

When  the chromium has been reduced, the pH of the waste water is
increased to 8.5 or 9.0 to precipitate  not  only  the  trivalent
chromium,  but also the copper and zinc.  If lime is used for the
pH adjustment, fluorides and most of the  arsenic  will  also  be
precipitated.  Care must be taken not to raise the pH beyond 9.5,
since  trivalent  chromium  is slightly soluble at higher values.
Additional arsenic and most of any residual copper  and  chromium
in solution can be precipitated by treating the waste with hydro-
gen  sulfide  gas,  or  by  adding  sodium sulfide.  Ammonium and
phosphate compounds are also reduced by this process.

This procedure is based on the fact that most  heavy  metals  are
precipitated as relatively insoluble metal hydroxides at alkaline
pH.   The  theoretical solubilities of some of the hydroxides are
quite low,  ranging  down  to  less  than  0.01  mg/1.   However,
theoretical  levels  are  seldom  achieved because of unfavorable
settling properties of the  precipitates,  slow  reaction  rates,
interference of other ions in solution, and other factors.  Among
the  ions  shown  in  Table 52, copper, zincr and chromium can be
reduced to levels substantially lower than 1.0 mg/1 by the  above
procedure.   Fluorides  have  a theoretical solubility at a pH of
8.5 to 9.0 of 8.5 mg/1, but residual concentrations on the  order
of  10  to  20  mg/1  are  more usual because of slow settling of
calcium fluoride.  The use of additional lime,  alum  coagulation
                              190

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and  filtration through bone char are reported to reduce fluoride
concentrations to 1.0 mg/1 or less.

The most difficult ion  to  reduce  to  acceptable  concentration
levels  is  arsenic.   Treatment of  water containing arsenic with
lime generally removes  only  about  85  percent  of  the  metal.
Removal rates in the range of 94 to 98 percent have been reported
for  filtration  through  ferric  sulfide  beds, coagulation with
ferric  chloride,  and  precipitation  with   ferric   hydroxide.
However,   none   of  these  methods  is  entirely  satisfactory,
particularly for arsenic concentrations above 20 mg/1.

Information on treatment processes for removing boron from  waste
waters is not available.

The  sludge resulting from the precipitation process contains the
heavy metals formerly in solution, along with  the  excess  lime.
It may also contain various organic materials of wood origin that
are  flocculated  and precipitated with the lime.  The sludge can
be filtered to reduce its volume and disposed of  in  a  suitable
manner.   The supernatant may be routed to a holding basin, as is
currently  being  done  by  several  plants,  given  a  secondary
treatment,  or  released,  depending  upon  its oxygen demand and
content of residual metals.  Work is in progress to determine  if
the sludge can be acidified and reused in the treating solution.

Representative  data  on  the laboratory treatment of waste water
containing CCA-type salt preservatives and  a  proprietary  fire-
retardant  formulation  composed mainly of ammonium and phosphate
compounds are given in Table  53.   Data  for  both  concentrated
solutions  and diluted waste water from a holding pond are given.
Average results of treatments conducted daily over a period of  a
year  on effluent from a plant are given in Table 54.  The latter
data were obtained by analyzing effluent from equipment  designed
by Russell to process waste water automatically.

Waste  waters  from  salt-type  treatments frequently are heavily
diluted  and,  consequently,   may   contain   very   low   metal
concentrations.   The  importance  of  subjecting  the waste to a
primary treatment to remove the metals, even when present in only
trace quantities, was referred to earlier.  Numerous studies have
shown that copper, chromium,  zinc,  and  arsenic  have  a  toxic
effect on biological waste treatment systems.

Ion   exchange   resins   of   the   sulfonated-polystyrene   and
quaternaryamine types have been employed on  a  commercial  scale
for   purification   and   recovery   of   metals   used  in  the
electroplating industry.  The technology involved in ion exchange
has  application  to  the  wood  preserving  industry,  but   the
economics  of  the  process  in  the purification of preservative
waste waters containing metal contaminants are unknown.   It  has
been suggested that inert sulfate and sodium ions and organic ma-
terials  in  these  waste  waters  would lower the metal-removing
                              191

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capacity of the  exchangers  sufficiently  to  make  the  process
impractical under mos.t circumstances.

Plant   experience   in   treating  waste  water  from  salt-type
treatments is limited.  This situation arises from the fact  that
steam  conditioning  of  stock prior to preservative injection is
not widely practiced among plants that use preservative and fire-
retardant salts.  Consequently, only  a  small  volume  of  waste
water  is  generated.   The  better  managed plants use the waste
water that is available  as  make-up  water  in  preparing  fresh
batches of treating solution.

Secondary Treatments

Biological   treatments,   chemical  oxidation,  activated-carbon
adsorption and various combinations of  these  basic  methods  of
waste  water  treatment have been used commercially, proposed for
such use, or tested in laboratory and pilot-plant  investigations
of wood preserving effluents.  Each of these methods is discussed
below  in  terms of:   (a)  characteristics relating to sensitivity
to shock loadings, availability  of  equipment,  and  maintenance
requirements;    (b)  efficiency  with  phenolic-type  wastes,  as
revealed by the literature; and (c) effluent  characteristics  of
wood  preserving  waste resulting from treatment.  Because of the
limited number of  wood  preserving  plants  that  are  currently
providing  secondary treatment for their waste, data for item (c)
is, in  some  instances,  based  on  grab  samples  collected  in
connection   with  this  study,  or  on  results  of  pilot-plant
investigations.

Biological. Treatments - Where a substantial volume of waste  with
a  high  organic  load  is  involved, cost considerations usually
dictate that biological oxidation be used as the major  component
in  the  waste treatment program.  Polishing treatments involving
chlorination, and possibly activated-carbon  filtration,  may  or
may  not be required, depending upon the design of the biological
system and  the  waste  loads  involved.   Each  of  the  several
biological  waste treating systems that have present or potential
application in the wood preserving industry is  covered  in  this
section.

Characteristics - According to Besselieure, trickling filters are
not  unduly  susceptible to disruption fay shock loads and recover
quickly if disruption occurs.  Their operation does  not  require
constant  attention,  and, when equipped with plastic media, they
are capable of handling high loading rates.  The  latter  feature
minimizes  the  land  area required.  For package units sized for
the relatively small volume of  discharge  at  the  average  wood
preserving  plant,  an  area  of 186 sq m  (2,000 sq ft) should be
adequate for the tower  (approximately 6 m  (20  ft)  in  diameter)
and associated equipment, including settling tank.

Processing  Efficiency  for  Phenolic  Wastes  -  The  literature
contains many references concerning waste water  treatment  using
                              194

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trickling   filters   in   the   petroleum  and  by-product  coal
industries.

Most of  the  references  report  on  efforts  to  reduce  phenol
concentrations  to  acceptable  levels.  Sweets, Hamdy and Weiser
studied  the  bacteria  responsible  for  phenol  reductions   in
industrial   waste   and   reported   good  phenol  removal  from
synthesized  waste  containing  doncentrations   of   400   mg/1.
Reductions  of 23 to 28 percent were achieved in a single pass of
the waste water through a pilot trickling filter having a  filter
bed only 30 cm (12 in) deep.

Waters  containing  phenol concentrations of up to 7500 mg/1 have
been successfully treated in laboratory tests conducted  by  Reid
and Libby.  Phenol removals of 90 to 90 percent were obtained for
concentrations  on  the  order of 400 mg/1.  Their work confirmed
that of others who found that strains of bacteria isolated from a
trickling filter could survive phenol concentrations of 1600 mg/1
and were able to oxidize phenols in concentrations of 450 mg/1 at
better than 99 percent efficiency.   Reid,  Wortman,  and  Walker
found  that  many  pure cultures of bacteria were able to live in
phenol concentrations  of  up  to  200  mg/1,  but  few  survived
concentrations  above  900  mg/1,  although  some  were  grown in
concentrations as high as 3700 mg/1.

Harlow,  Shannon,  and  Sercu  described  the  operation   of   a
commercial-  size  trickling  filter  containing  "Dowpac" filter
medium that was used to process waste water  containing  25  mg/1
phenol  and  450 to 1,900 mg/1 BOD.  Reductions of 96 percent for
phenols and 97 percent for BOD were obtained in this unit.  Their
results  compare  favorably  with   those   reported   by   other
researchers.   BOD reductions of 90 percent in a trickling filter
using a 1:2 recycle ratio.  Dickerson and Laffey obtained  phenol
and  BOD  reductions of 99.9 and 96.5 percent, respectively, in a
trickling filter used to process refinery waste water.

Davies, Biehl, and Smith reported  on  a  combination  biological
waste-treatment  system  employing  a  trickling  filter  and  an
oxidation pond.  The filter, which  was  packed  with  a  plastic
medium,  was  used for a roughing treatment of tO.6 million I/day
 (2.8 million  gal/day)  of  waste  water,  with  £inal  treatment
occurring in the oxidation pond.  Removal rates of 95 percent for
phenols  and  60  percent  for  BOD  were obtained in the filter,
notwithstanding the fact that the pH  of  the  influent  averaged
9.5.

Biological  treatment of refinery waste waters, using a series of
4 trickling filters has been studied.  Each filter  was  operated
at a different recycle ratio.  The waste contained 22 to 125 mg/1
of  oil.   BOD  removal  was  adversely  affected by the oil, the
lowest removal rates corresponding to the periods  when  the  oil
content  of  the  influent was highest.  Phenol removal was unaf-
fected by oil concentrations within the range studied.
                              195

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Prather and Gaudy found that significant reductions in COD,  BOD,
and  phenol  content  of  refinery  waste  water were achieved by
simple aeration treatments.  They concluded that this  phenomenon
accounted  for  the  high  allowable loading rates for biological
treatments such as trickling filtration.

Treatment of Wood Preserving  Effluents  -  The  practicality  of
using  the  trickling  filters  for  secondary treatment of waste
waters from the wood preserving industry was explored by Dust and
Thompson.  A pilot unit containing a 6.4 m  (21 ft) filter bed  of
plastic  media was used in their study.  Creosote waste water was
applied at BOD loading rates of from 400 to 3050 kg/1000 cu m/day
(25 to  190  lb/  1000  cu  ft/day).   The  corresponding  phenol
loadings were 1.6 to 54.6 kg/1000 cu m/day  (0.1 to 3.4 lb/1000 cu
ft/day).   Raw  feed-to-recycle  ratios  varied from 1:7 to 1:28.
The pilot unit was  operated  and  daily  samples  collected  and
analyzed  over a period of 7 months that included both winter and
summer operating conditions.

Because of waste water characteristics at  the  particular  plant
cooperating  in  the study, the following pretreatment steps were
necessary: (a) equalization of wastes;  (b) primary  treatment  by
coagulation for partial solids removal; (c)  dilution of the waste
water  to obtain BOD loading rates commensurate with the range of
raw flow levels provided by the equipment; and  (d)  addition  to
the  raw feed of supplementary nitrogen and phosphorus.  Dilution
ratios of 0 to 14 were used.

The efficiency of the  system  was  essentially  stable  for  BOD
loadings  of  less  than  1200  kg/1000  cu  m/day (75 lb/1000 cu
ft/day). . The best removal rate was achieved when  the  hydraulic
application  rate  was 2.851/min/sq m  (0.07 gal/min/sq ft) of raw
waste and 40.7 1/min/sg m  (1.0 gal/min/sq ft)  of recycled  waste.
The COD, BOD, and phenol removals obtained under these conditions
are  given  in Table 55.  Table 56 shows the relationship between
BOD loading rate and removal efficiency.  BOD removal  efficiency
at  loading rates of 1060 kg/1000 cu m/day  (66 lb/1000 cu ft/day)
was on the order of 92 percent, and was not improved  at  reduced
loadings.  Comparable values for phenols at loading rates of 19.3
kg/1000 cu m/ day (1.2 lb/1000 cu ft/day)  were about 97 percent.

Phenol content was more readily reduced to levels compatible with
existing  standards  than  was  BOD  content.   Consequently, the
sizing of commercial units from data  collected  from  the  pilot
unit  was  based  on  BOD removal rates.  Various combinations of
filter-bed depths, tower diameters, and volumes of  filter  media
that  were calculated to provide a BOD removal rate of 90 percent
for influent having a BOD of 1500 mg/1 are shown in Table 57  for
a plant with a flow rate of 75,700 I/day  (20,000 gal/day).

Activated Sludge and Aerated Lagoon - Characteristics - Activated
sludge  treatments  which  employ the complete-mix alternative to
the conventional process are very resistant to disruptions caused
by shock loads, offer low operation and  maintenance  costs,  low
                              196

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    TABLE 55  BOD, COD, AND PHENOL LOADING AND REMOVAL RATES FOR
    PILOT TRICKLING FILTER PROCESSING A CREOSOTE WASTEWATER
         Measurement                         Characteristic
                                     BOD          COD        Phenol
Raw Flow Rate (gpm/ sq  ft)             0.07         0.07        0.07

Recycle Flow Rate (gpm/sq  ft)         1.0          1.0         1.0

Influent Concentration  (mg/1)      1698         3105          31

Loading Rate (IbAOOO cu ft)          66.3        121.3         1.2

Effluent Concentration  (mg/1)       137          709           1.0

Removal (%)                          91.9         77.0        99+
                                   197

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TABLE 56  RELATIONSHIP BETWEEN BOD LOADING AND TREATABILITY
FOR PILOT TRICKLING FILTER PROCESSING A CREOSOTE WASTEWATER
     BOD
   Loading                 Removal           Treatability*
 (Ib/cu  ft/day)               <%)                Factor
23 91
26 95
37 92
53 93
66 92
76 82
85 80
115 75
156 62
0.0301
0.0383
0.0458
0.0347
0.0312
0.0339
0.0286
0.0182
0.0130
 *Based on the equation:

                  Le =  e^/QO.S  (Germain, 1966)
                  Lo

  in which Le = BOD concentration of settled effluent, Lo =
  BOD of feed, Q = hydraulic application rate of raw waste
  in gpm/ft , D = depth of media in feet, and K = treatability
  factor (rate coefficient).
                                198

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TABLE 57  SIZING OF TRICKLING FILTER FOR A WOOD PRESERVING PLANT

    (NOTE:  Data are based on a flow rate of 20,000 gallons per
            day, with filter influent BOD of 1500 and effluent
            BOD of 150.)
Depth of Raw flow Recycle flow Filter Volume
filter (gpm/ sq ft) (gpm/ sq ft) Surface Tower of
bed filter filter area dia. media
(ft) surface) surface) (sq ft) (ft) (cu ft)
10.7 0.019
12.5 0.026
14.3 0.034
16.1 0.044
17.9 0.054
19.6 0.065
21.4 0.078
TABLE 58 SUBSTRATE
SLUDGE
Aeration Time, Days
COD Raw, mg/1
COD Effluent, mg/1
% COD Removal
COD Raw/COD Effluent
0.73 708 30.0 7617
0.72 520 25.7 6529
0.71 398 22.5 5724
0.70 315 20.0 5079
0.69 255 18.0 4572
0.68 210 16.3 4156
0.67 177 15.0 3810
REMOVAL AT STEADY-STATE CONDITIONS IN ACTIVATED
UNITS CONTAINING CREOSOTE WASTEWATER
5.0 10.0 14.7 20.1
447 447 442 444
178 103 79 67
60.1 76.9 82.2 84.8
2.5 4.3 5.6 6.6
                                  199

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initial  cost,  and  have small land requirements.  Package units
designed to £*eat the waste water from an average wood preserving
plant could be located on an area pf approximately 93 sq m  (1000
sq  ft).   Additional  space would be required for a pretreatment
equalization reservoir and, where required,  flocculation  tanks.
A  system  will occupy an area of approximately 140 sq m (1500 sq
ft),   including   equipment   for   pre-   and    post-treatment
chlorination.             •

An  aerated  lagoon  is a special type of complete-mix, activated
sludge system, without sludge recycle.  It normally  is  operated
in  conjunction  with  a polishing pond into which waste from the
lagoon is discharged.  Both the lagoon  and  polishing  pond  are
usually  constructed  with  earthen  embankments, a feature which
reduced the cost of the system compared with the activated sludge
process.  This method  of  treatment  has  essentially  the  same
advantages  as  the  conventional  complete-mix, activated sludge
system, but does require more land area.

Processing  Efficiency  for  Phenolic  Wastes  -   Treatment   of
municipal  and  mixes  of  municipal and industrial wastes by the
activated sludge process is common practice.  In recent years the
process has also been adapted to  industrial  wastes  similar  in
composition  to  that  of  effluents from wood preserving plants.
Ninety nine  percent  oxidation  efficiency  for  BOD5  has  been
obtained  in  petrochemical  wastes.   Coe reported reductions of
both BODji and phenols of 95  percent  from  petroleum  wastes  in
bench-scale  tests of the activated sludge process.  Optimum BOD5
loads of 2247 kg/1000 cu m/day (140  lb/1000  cu  ft/  day)  were
obtained  in  his  work*   Coke plant effluents were successfully
treated by Ludberg and Nicks (87) , although they experienced some
difficulty: in start-up of the activated sludge system because  of
the high phenol content of the water.

The  complete  mixed,  activated  sludge  process was employed to
process a high-phenolic waste water from  a  coal-tar  distilling
plant  in  Ontario.  Initial phenol and COD concentrations of 500
and 6,000 mg/1,  respectively,  were  reduced  in  excess  of  99
percent for phenols and 90 percent for COD.


Cooke  and  Graham  employed the complete-mixed, activated sludge
system  to  treat  waste  containing  phenols,   organic   acids,
thiocyanates, and ammonia using detention times of 8 to 50 hours.
At  feed  rates of 144 to 1605 kg/1000 cu m/day  (9 to TOO lb/1000
cu ft/day), phenol content was reduced from 281 mg/1 to 62  mg/1,
for a removal rate of 78 percent.

The  employment  of  aerated  reaction units on a continuous flow
basis has been used  to  treat  coke  gasification  plant  waste.
Badger and Jackson have found that a two-day detention period was
sufficient to remove 90 percent of the phenol from a waste stream
containing up to 5,000 mg/1 of the chemical.
                              200

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Nakashio  successfully treated coal gas washing liquor containing
1,200 mg/1 of phenols in a study that lasted more  than  a  year.
Phenol  concentration  was  reduced  by  more  than  99  percent.
Similar phenol removal rates  have  been  obtained  by  Reid  and
Janson   in  treating  waste  water  containing  cresols  by  the
activated sludge process.

In  a  report  of  pilot  and  full-scale  studies  performed  by
Bethlehem  steel Corporation, phenol removal efficiencies greater
than  99.8  percent  were  obtained  using  the   complete-mixed,
activated  sludge  process.  Loading  rates  of 0.86 kg phenol/kg
MLSS/day were used successfully.  Phenol influent  concentrations
of 3,500 mg/1 were reduced to 0.2 mg/1 in the effluent.

Treatment  of  Wood  Preserving.   Effluents  -  Dust and Thompson
conducted bench-scale tests of complete-mixed,  activated  sludge
treatments  of  creosote and pentachlorophenol waste waters using
5-liter units and detention times of 5, 10, 15, and 20 days.  The
operational  data  collected  at  steady  state   conditions   of
substrate  removal  for the creosote waste are shown in Table 58.
A plot of these data showed that the  treatability  factor,  K  =
0.30  days-1  (Figure 39).  The resulting design equation, with t
expressed in days, is:

                      Le =        Lo
                              1 + 0.30t

           where:     Lo =  COD in raw waste
                      Le =  COD in effluent

A plot of percent  COD  removal  versus  detention  time  in  the
aerator, based on the above equation, is shown in Figure 40.  The
figure shows that an oxidation efficiency of about 85 percent can
be  expected  with  a  detention time of 20 days in units of this
type.

Work done with pentachlorophenol waste was conducted to determine
the degree of biodegradability of  this  chemical.   Cultures  of
bacteria,  prepared  from  soil  removed  from  a  drainage ditch
containing pentachlorophenol waste, were used  to  inoculate  the
treatment  units.   Feed  to  the  units  contained  10  mg/1  of
pentachlorophenol and 2,400 mg/1 COD.  For the two  5-liter  units
(A  and  B)  the feed was 500 and 1000 ml/day and detention times
were, in order, 10 and 5 days.

Removal rates for pentachlorophenol and COD are  given  in  Table
59.   For the first 20 days Unit A removed only 35 percent of the
pentachlorophenol added to the unit.  However, removal  increased
dramatically after this period and averaged 94 percent during the
remaining  ten  days  of  the study.  Unit B consistently removed
over 90 percent of the pentachlorophenol added.  Beginning on the
46th day and continuing through the 51st  day,  pentachlorophenol
loading  was increased at two-day intervals to a maximum of about
                              201

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no
o
rsj
                                                   Slope= K =0*30 day
                                                                    -1
                                                         Le =
                                                                Lo
                                                              1+0.301
                                      5               10


                                         Aeration  Time (Days)
                          15
                         FIGURE 39
DETERMINATION OF REACTION RATE CONSTANT

FOR A CREOSOTE WASTEWATER

-------
               o
               o
               x 90
              tt»
ro
o
CO
               (0
                 80
                 70
O



8 50
d)   |
a

  40
                                                                  Lo
                                                                1+0.301
                                                  10


                                        Aeration Time (Days)
                                                  15
20
                          FIGURE 40
                          - COD REMOVAL FROM A CREOSOTE WASTEWATER BY

                            AERATED LAGOON WITHOUT SLUDGE RETURN

-------
TABLE 59  REDUCTION IN PENTACHLOROPHENOL AND COD IN
    WASTEWATER TREATED IN ACTIVATED SLUDGE UNITS


DAYS

1-5
6-10
11-15
16-20
21-25
26-30
31-35

1-5
6-10
11-15
16-20
21-25
26-30
31-35
36-40
41-45
46-47
48-49
50-51
RAW
WASTE
(mg/1)
COD
2350
2181
2735
2361
2288
2490
2407
PENTACHLOROPHENOL
7.9
10.2
7.4
6.6
7.0
12.5
5.8
10.3
10.0
20.0
30.0
40.0
EFFLUENT FROM UNIT
a
"A"

78
79
76
82
90
—
83

20
55
33
30
—
94
94





Removal)
"B"

78
79
75
68
86
84
80

77
95
94
79
87
94
91
91
96
95
97
99
                             204

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     TABLE 60  RESULTS OF LABORATORY TESTS OF SOIL IRRIGATION
                     METHOD OF WASXEWATER TREATMENT*

Loading Rate
(Liters/ha/day)
32,800
(3,500)
49,260
(5,250)
82,000
(8,750)
Loading

Length
Test
(Week)
31
13
14
rates in
COD REMOVAL
of Avg. % COD Last Week
Removal to of Test
Breakthrough %
99.1 (22 wks) 85.8
99.6 99.2
99.0 (4 wks) 84.3
parentheses in gallons/acre/day
Phenol
Avg. %
Removal
(All Weeks)
98.5
99.7
99.7

*Creosote wastewater containing 11,500 mg/liter of COD and 150 mg/liter
of phenol was used.
                                    205

-------
40  mg/1.   Removal  rates  for  the  three  two-day  periods  of
increased loadings were 94, 97, and 99 percent.

COD  removal for the two units averaged about 90 percent over the
duration of the study.

Also working with the activated sludge process, Kirsh  and  Etzel
obtained  removal  rates  for  pentachlorophenol  in excess of 97
percent using an 8-hour detention time and a  feed  concentration
of 150 mg/1.  The pentachlorophenol was supplied to the system in
a  mixture  that  included 100 mg/1 phenol.  Essentially complete
decomposition of the phenol was obtained, along with a 92 percent
reduction in COD.

Soil Irrigation - Characteristics - The principal feature of  the
soil   irrigation   method   of  waste  water  treatment  is  its
simplicity.  Water that has  been  freed  of  surface  oils  and,
depending  upon  the  presence  of  emulsified oils, treated with
flocculated chemicals and filtered through a sand bed  is  simply
sprayed onto a prepared field.  Soil microorganisms decompose the
organic matter in the water in much the same fashion as occurs in
more conventional waste treatment systems.

In  addition to its simplicity, soil irrigation has the advantage
of low capital investment, exclusive of land costs, low operating
and  maintenance  costs,  requires  a   minimum   of   mechanical
equipment,  and  produces  a  high  quality  effluent in terms of
color, as well as oxygen demand and other  pertinent  parameters.
Its chief disadvantage is that its use requires a minimum area of
approximately  one  ha/33,000 1 of discharge/day  (one ac/3500 gal
of discharge/day).  This requirement makes the method impractical
in locations where space is at a premium.  However, it is  not  a
major  problem  for  the many plants in rural areas where land is
relatively inexpensive.

Processing Efficiency For Phenolic Wastes   -  Effluents  from  a
number  of  different  types of industries have been successfully
disposed of by soil irrigation.  At least 20 types of  industrial
wastes  that  have  been treated by this method.  Among these are
several wastes high in phenol content.  Removal  efficiencies  as
high as 99.5 percent for both BOD and phenols were reported.

Fisher  reported  on  the  use  of soil irrigation to treat waste
waters  from  a   chemical   plant   that   had   the   following
characteristics:

     pH           9.0 to 10.0
     Color        5,000 to 42,000 units
     COD          1,600 to 5,000 mg/1
     BOD          800 to 2,000 mg/1

Operating  data  from a 0.81 ha  (2 ac) field, when irrigated at a
rate of 18,690 1/ha/day  (2000  gal/ac/day)  for  a  year,  showed
                                    206

-------
color  removal  of  88  to 99 percent and COD removal of 85 to 99
percent.

The same author reported on the  use  of  this  method  to  treat
effluent  from two tar plants that contained 7,000 to 15,000 mg/1
phenol and 20,000 to 54,000 mg/1 COD.  The waste was  applied  to
the  field  at a rate of about 23,400 1/ha/day (2500 gal/ac/day).
Water leaving the area had COD and phenol  concentrations  of  60
and   1   mg/1,   respectively.   Based  on  the  lower  influent
concentration  for  each  parameter,   these   values   represent
oxidation  efficiencies  of  well over 99 percent for both phenol
and COD.

Bench-scale treatment of coke plant effluent by  soil  irrigation
has  also  been  studied.   Wastes  containing  BOD5  and  phenol
concentrations  of  5,000  and  1,550  mg/1,  respectively,  were
reduced  by  95  and 99 percent when percolated through 0.9 m  (36
in) of soil.  Fisher pointed out that less efficient removal  was
achieved  with  coke-plant  effluents  using the activated sludge
process, even when the waste was diluted with high-quality  water
prior  to  treatment.   The  effluent  from the units had a color
rating of 1,000 to 3,000 units, compared to 150 units  for  .water
that had been treated by soil irrigation.
                                                        v
Treatment  of  Wood  Preserving  Effluents  - Both laboratory and
pilot scale field tests of  soil-irrigation  treatments  of  wood
preserving  waste  water were conducted by Dust and Thompson.  In
the laboratory tests, 210 liter  (55 gal) drums containing a heavy
clay soil 60 cm  (24 in) deep were  loaded  at  rates  of  32,800,
49,260, and 82,000 1/ha/day  (3,500, 5,250, and 8,750 gal/ac/day).
Influent  COD and phenol concentrations were 11,500 and 150 mg/1,
respectively.  Sufficient nitrogen and phosphorus were  added  to
the waste to provide a COD:N:P ratio of 100:5:1.  weekly effluent
samples  collected  at  the bottom of the drums were analyzed for
COD and phenol.

Reductions of 99+ percent in COD content of the waste water  were
attained  from  the  first  week  in  the case of the two highest
loadings and from the fourth week  for  the  lowest  loading.   A
breakthrough occurred during the 22nd week for the lowest loading
rate  and  during  the  fourth week for the highest loading rate.
The COD removal steadily decreased thereafter for the duration of
the test.  Phenol removal showed no such reduction,  but  instead
remained  high throughout the test.  The average test results for
the three loading rates are given in Table  61.   Average  phenol
removal  was  99+  percent.   Removal  of COD exceeded 99 percent
prior to breakthrough and averaged over  85  percent  during  the
last week of the test.

The field portion of Dust and Thompson's study was carried out on
an  0.28 ha  (0.7 ac) plot prepared by grading to an approximately
uniform slope and seeded with  grasses.   Wood  preserving  waste
water  from  an equalization pond was applied to the field at the
rate of 32,800 1/ha/day  (3,500 gal/ac/day) for a period  of  nine
                              207

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TABLE £1  REDUCTION OF COD AND PHENOL CONTENT IN WASTEWATER
              TREATED BY SOIL IRRIGATION
Soil Depth (centimeters)
Month Raw Waste 0

July
August
September
October
November
December
January
February
March
April

2235
2030
2355
1780
2060
3810
2230
2420
2460
2980
COD (mg/1)
1400
1150
1410
960
1150
670
940
580
810
2410
30

— —
—
—
150
170
72
121
144
101
126
60

__
—
—
—
170
91
127
92
102
—
120

66
64
90
61
46
58
64
64
68
76
Average % Removal
(weighted)

July
August
September
October
November
December
January
February
March
April


235
512
923
310
234
327
236
246
277
236
55.0
Phenol (ms/l)
186
268
433
150
86
6
70
111
77
172
94.9

ta—
—

4.6
7.7
1.8
1.9
4.9
2.3
1.9
95.3

w— _
—
—
—
3.8
9.0
3.8
2.3
1.9
0.0
97.4

1.8
0.0
0.0
2.8
0.0
3.8
0.0
1.8
1.3
0.8
Average % Removal
   (weighted)               55.4     98.9     99.2      99.6
                              208

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months.   Average  monthly influent COD and phenol concentrations
ranged  from  2,000  to  3,800  mg/1  and  235   to   900   mg/1,
respectively.   Supplementary  nitrogen  and  phosphorus were not
added.  samples for analyses were collected weekly at soil depths
of G  (surface), 30, 60, and 120 cm  (1, 2, and 4 ft).

The major biological reduction in COD and phenol content occurred
at the surface and in the upper 30 cm  (1  ft)  of  soil.   A  COD
reduction  of  55.0 percent was attributed to overland flow.  The
comparable reduction for phenol content was 55.4  percent   (Table
61).   Average  COD reductions at the three soil depths, based on
raw waste to the  field,  were  94.9,  95.3,  and  97.4  percent,
respectively,  for  the  30-,  60-, and 120 cm (1-, 2-, and 4-ft)
depths.  For phenols, the reductions were, in order, 98.9,  99.2,
and 99.6 percent.

Color  of  the  waste  water  before  and after treatment was not
measured.  However, the influent to the field was dark brown  and
the  effluent was clear.  Samples taken from the 6C and 120 cm  (2
and 4  foot) depths showed no discoloration.

The application of the waste water to  the  study  area  did  not
interfere  with  the  growth of vegetation.  On the contrary, the
area was mowed several times during the summer months to  control
the height of native grasses that became established.

The soil percolation method for treating the creosote waste water
from   the  wood  preserving  plant  consistently showed a greater
percentage removal of COD and phenol than  either  the  activated
sludge or the trickling filter methods.

Oxidation   Ponds   -   Characteristics  -  Oxidation  ponds  are
relatively simple to operate and, because of their large  volume,
difficult  to  disrupt.   Operation  and  maintenance  costs  are
usually lower than  for  other  waste  treating  methods.   Their
disadvantages  are  numerous.  Included among these are;   (a) low
permissible loading rate, which necessitates  large  land   areas;
 (b)   abrupt  changes in efficiency related to weather conditions;
 (c) difficulty of restoring a pond to operating  condition  after
it  has  been  disrupted;   (d) tendency to become anaerobic, thus
creating odor problems, and  (e) effluents containing algal  cells,
themselves a pollutant.

Processing Efficiency for Phenolic Wastes - Only a few  cases  of
the   use of oxidation ponds to treat phenolic wastes are recorded
in recent literature.  The American Petroleum Institute's "Manual
on Disposal of Refinery Wastes" refers to several industries that
have  successfully used this method.

Montes reported  on  results  of   field  studies  involving  the
treatment  of  petrochemical  wastes   using  oxidation ponds.  He
obtained BOD reductions of 90 to 95 percent in  ponds  loaded  at
the rate of 84 kg/ha/day of .BOD  (75 Ib/ac/day) .
                               209

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Phenol  concentrations  of  990  mg/1 in coke oven effluents were
reduced to about 7 mg/1  in  field  studies  of  oxidation  ponds
conducted  by  Biczysko  and  Suschka.  Similar results have been
reported by Skogen for a refinery waste.

Treatment of Wood Preserving Effluents  -  Oxidation  ponds  rank
high  among  the  various  methods that wood preserving companies
plan to use to treat their waste water  (Table 48).  However,  the
literature contains operating data on only one pond used for this
purpose.


As  originally  designed  and  operated in the early 1960's, this
waste treatment system consisted  of  holding  tanks  into  which
water  from  the  oil-recovery  system  flowed.  From the holding
tanks the water was sprayed into a terraced hillside  from  which
it  flowed  into  a mixing chamber adjacent to the pond.  Here it
was diluted 1:1 with creek  water,  fortified  with  ammonia  and
phosphorus,  and discharged into the pond proper.  Retention time
in the pond was 45 days.  The quality of the effluent  was  quite
variable, with phenol content ranging up to 40 mg/ 1.

In   1966  the  system  was  modified  by  installing  a  raceway
containing a surface aerator and a settling basin in a portion of
the pond.  The discharge from the mixing  chamber  now  enters  a
raceway  where it is treated with a flocculating agent.  The floe
formed collects in the settling  basin.   Detention  time  is  48
hours  in  the  raceway and 18 hours in the settling basin.  From
the settling basin, the waste water enters the pond proper.

These modifications in effect changed the treating system from an
oxidation pond to a  combination  aerated  lagoon  and  polishing
pond.   The  effect  on the quality of the effluent was dramatic.
Figure 41 shows the phenol content at the  outfall  of  the  pond
before  and after installation of the aerator.  As shown by these
data, phenol content decreased abruptly from an average of  about
40 mg/1 to 5 mg/1.

Even  with  the  modifications  described,  the efficiency of the
system remains seasonally dependent.  Table 62 gives  phenol  and
BOD5  values  for  the  pond effluent by month for 1968 and 1970.
The smaller fluctuations in these parameters in  1970 as  compared
with 1968 indicate a gradual improvement in the system.

chemic al   Oxidation   -   Phenolic  compounds,  in  addition  to
contributing to  the  oxygen  demand  of  wood  preserving  waste
waters,  largely  account  for  the toxic properties of effluents
from creosote and pentachlorophenol treatments.  These  compounds
can  be  destroyed  by chemical oxidation.  Oxidizing agents that
have been successfully used for this  purpose  are  chlorine  and
ozone.

chlorine  - Many references to the chlorination of phenol-bearing
waters exist in the literature.  Chlorine  gas  and  calcium  and
                              210

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TABLE 62  AVERAGE MONTHLY PHENOL AND BOD CONCENTRATIONS  IN  EFFLUENT
          FROM OXIDATION PQND
(mg/ liter)
1968
Month
January
February
March
April
May
June
July
August
September
October
November
December
Phenol
26
27
25
11
6
5
7
7
7
16
7
11
BOD
290
235
190
150
100
70
90
70
110
150
155
205
1970
Phenol
7
9
6
3
1
1
1
1
1
—
—
__
BOD
95
140
155
95
80
60
35
45
25
—
—
__
                            211

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                                                  ZIZ
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                                  Phenol Content (mg/l)

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                                  O       W        O    --?*-
                                                                             n
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-------
sodium  hypochlorite  have  been  used  most extensively for this
purpose.   Direct  treatment  with  gaseous  chlorine   using   a
continuous-flow   system  is  simpler  and  less  expensive  than
hypochlorite where large volumes of waste water must be  treated.
However,  for  batch-type  treatments involving small waste water
volumes, hypochlorite is probably the more practical.

Chlorine dioxide may also be used to oxidize phenols.  It has the
advantage over other sources of chlorine of short reaction  time,
does  not  require  close control of pH and temperature, does not
produce chlorophenols, and is effective at ratios of chlorine  to
phenol  of 1:1 or 2:1.  Its primary disadvantages are its lack of
stability, which requires that it be produced as  used,  and  its
relatively high cost.

The theoretical ratio of chlorine to phenol required for complete
oxidation  is  about  6:1.   For  m-cresol  the  ratio is 3.84:1.
However,  because  of  the  presence  in  waste  water  of  other
chlorine-consuming  compounds,  much  higher ratios are required.
Thompson and Dust found that the minimum concentration of calcium
hypochlorite needed to destroy  all  phenols  in  creosote  waste
water  was  equivalent to a chlorine:phenol ratio of from 14:1 to
65:1.  The exact ratio varied  with  the  pH,  COD  content,  and
source    of    the   waste   water.    Comparable   ratios   for
pentachlorophenol  ranged  as  high   as   300:1   when   calcium
hypochlorite  was  used  to  700:1  for chlorine gas.  Generally,
approximately two times as much gaseous chlorine was required  to
oxidize  a  given  weight  of  pentachlorophenol as chlorine from
calcium hypochlorite.

In other work. Dust and Thompson analyzed waste water samples for
COD, phenol, and pentachlorophenol content following chlorination
with quantities of calcium hypochlorite equivalent to  0  to  3.0
g/1  of  chlorine.   Typical  results  are  shown  in  Table  63.
Treatment of creosote waste water achieved a reduction in  phenol
content  of  95  to  100  percent,  as  determined  by procedures
recommended by APHA   (NOTE:   This  qualification  is  necessary,
since the 4-amino antipyrine test for phenols does not detect all
chlorinated  phenols  and  cresols).   However, as illustrated in
Table 63, a residual phenol content of 5  to  10  mg/1  that  was
resistant  to  oxidation  remained  in some samples.  Substantial
reductions in COD were also obtained by the treatments.  However,
practically all of the reduction  in  COD  occurred  at  chlorine
doses of 2 g/1 or less.

In  the  same  study,  both chlorine gas and calcium hypochlorite
were used to treat pentachlorophenol waste water adjusted  to  pH
levels  of  4.5, 7.0, and 9.5.  The results, which are summarized
in  Tables  64  and  65,  showed  that  the  efficiency  of   the
treatments,  in  terms of the ratio of weight of chlorine used to
weight of pentachlorophenol removed, varied with the  pH  of  the
waste water, the source of chlorine, and whether or not the waste
was flocculated prior to chlorination.
                              213

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TABLE 63  EFFECT OF CHLORINATION ON THE COD AND  PHENOLIC  CONTENT
             OF PENTACHLOROPHENOL AND CREOSOTE WASTEWATERS
Ca(OCl)2 as
Chlorine
(g/liter)
0
0.5
1.0
1.5
2.0
3.0
PCP Wastewater
(mg/liter)
COD
—
8150
7970
8150
7730
7430
PCP
40.7
17.3
13.1
12.0
10.4
0.0
Creosote Wastewater
(mg/liter)
COD
5200
4800
4420
4380
4240
3760
Phenol
223.1
134.6
65.3
15.4
10.0
5.4
                             214

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TABLE 64  EFFECT OF CHLORINATION WITH CALCIUM HYPOCHLORITE
          ON THE PENTACHLOROPHENOL CONTENT OF WASTEWATER
               Pentachlorophenol (mg/liter)
Ca(PCl)2 as
Chlorine
(g/liter)
0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
TABLE 65

Unflocculated
PH
4.5 7.0 9.5
21.5 19.0 20.5
10.0 14.0 10.0
8.0 10.0 8.0
6.0 8.0 8.0
6.0 7.5 8.0
3.5 6.0 5.0
2.0 6.0 4.0
2.0 5.8 4.0

4.5
12.0
6.0
4.0
2.0
0.0
0.0
0.0
0.0
EFFECT OF CHLORINATION WITH CHLORINE
THE PENTACHLOROPHENOL CONTENT
Flocculated
PH
7.0
12.0
9.0
8.0
5.0
3.6
0.0
0.0
0.0
GAS ON

9.5
14.0
11.0
9.0
6.0
7.0
4.0
0.0
0.0

OF WASTEWATER
Pentachlorophenol (mg/liter)
Chlorine
(g/liter)
0.0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
10.0
Unflocculated
PH
4.5 7.0 9.5
22.0 20.0 18.0
13.0 14.0 16.0
10.0 12.5 15.0
9.0 9.0 11.5
8.0 8.0 11.5
8.0 8.0 8.0
10.0 8.0 11.0
14.0 11.5 12.0
14.0 11.5 14.0

4.5
18.0
16.0
14.0
10.0
8.0
7.5
2.0
0.0
0.0
Flocculated
PH
7.0
17.0
14.0
13.0
14.0
10.0
8.0
6.0
2.0
2.0

9.5
19.5
16.5
11.0
11.0
8.0
8.0
6.0
4.0
2.0
                             215

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TABLE 66  EFFECT OF CHLORINATION OF PENTACHLOROPHENOL.WASTE ON COD
Test Conditions
Calcium Hypochlorite
pH - 4.5






Calcium Hypochlorite







Chlorine Gas
pH - 4.5







Chlorine- 6s
pH = 7.0







Available Chlorine
(g/liter)
0.0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
0.0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
0.0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
10.0
0.0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
10.0
COD
(mg/liter)
24,200

10,650

10,600

10,300

23,800

10,300

10,200


10,050
20,400



10,250

10,500

10,200
23,600



9,760

10,700

11,250
                            216

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A  large  proportion  of the chlorine added to the waste water in
the above studies was consumed  in  oxidizing  organic  materials
other  than  phenolic  compounds.  This is indicated by the major
reductions in COD that occurred coincident  to  the  chlorination
treatments.   For  unflocculated  waste,  the COD averaged 24,000
mg/1  before  and  10,300  mg/1  after  treatment  with   calcium
hypochlorite,  a  reduction  of  58 percent (Table 66) .  The com-
parable reduction for samples treated with chlorine  gas  was  55
percent.   These  reductions were obtained at the maximum dose of
chlorine employed; that is, 5 g/1 for calcium hypochlorite and 10
g/1 for chlorine gas.  However, practically all of the  reduction
in  COD  occurred at chlorine doses of 1 g/1 or less, in the case
of samples treated with the hypochlorite, and 2 g/1 or  less  for
those  treated  with chlorine gas.  For example, a typical sample
of raw waste treated with chlorine gas  had  an  initial  COD  of
20,400 mg/1.  This value was reduced to 10,250 mg/1 by a chlorine
dose  of  2  g/1.   The  addition  of  10 g/1 of chlorine further
reduced the COD to only 10,200 mg/1.  These data indicate that  a
portion  of  the organic content of the waste water was resistant
to chemical oxidation.

The reduction in COD caused by chlorination of  raw  waste  water
was  practically  the  same as that achieved by flocculation with
lime and a polyelectrolyte.

Chlorination of phenol-bearing waters has  long  been  associated
with odor and taste problems in municipal water supplies.  Phenol
itself   apparently   does   not   impart   taste   to  water  in
concentrations below about 60 mg/1.  its significance as a  taste
and  odor  problem  arises  from  its  reaction  with chlorine to
produce chlorophenols.  Some of the latter group of chemicals are
reported to impart taste in  concentrations  as  low  as  0.00001
mg/1.

Ingols  and Ridenour postulated that a quinone-like substance was
responsible for the taste and odor problem of chlorinated  water,
and  that  this  substance  was  an  intermediate  product  in  a
succession  of  chlorinated   products   produced   by   chlorine
treatments  of  phenol.   A  ratio  of  5 to 6 g of chlorine/g of
phenol  was  found  to  eliminate  the   taste   problem.    They
hypothesized  from  this  result that high levels of chlorination
rupture the benzene ring to form maleic acid.  Later  studies  by
Sttinger  and  Ruchoft  largely  substantiated earlier work which
showed that taste intensity increases with  chlorine  dosage  and
then decreases with further chlorination, until no taste remains.
Results  of  work by these authors on the chlorination of various
phenolic compounds and the quantities  of  chlorine  required  to
eliminate  taste are given in Table 67.  These data indicate that
a chlorine-to-phenol ratio of  5:1  would  be  adequate  to  form
chlorination end products.  Work reported by others show that for
m-cresol this ratio is 3.84:1.  A ratio of 5:1 resulted in a free
chlorine residual after a reaction time of 2 hours.
                              217

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     TABLE 67  CHLORINE REQUIRED TO ELIMINATE TASTE IN AQUEOUS
               SOLUTIONS OF VARIOUS PHENOLIC COMPOUNDS
Chlorine Required To
Eliminate Taste
(mg/1)
Phenol
0-Cresol
M-Cresol
P-Cresol
2-Chlorphenol
4-Chlorophenol
2-, 4-Dichlorophenol
2-, 4-, 6-Trichlorophenol
2-, 4-, 5-Trichlorophenol
2-, 3-, 4-, 6-Tetrachlorophenol
Pentachlorophenol
4
5
5
3
3
3
2
*
*
*
*
Chlorine Added
To Produce Free
Residual (mg/1)
7
5
5
4
5
6
6
3
2
1.5
1.0
*Could not be tasted
                                 218

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More  recent work by the Manufacturing Chemists Association shows
that  the  reaction  between  chlorine  and  phenolic   compounds
proceeds  at  a  rapid  rate  for  the  first  15  minutes and is
essentially  complete  after   2   hours   contact   time.    For
concentrations  of m-cresol of 10 and 20 mg/1, the application of
50 and 100 mg/1 of chlorine produced  a  free  chlorine  residual
after 2 hours.  A residual chlorine content after 2 hours contact
time  was  obtained  for phenol only when chlorine was applied at
ten times the level of phenol.  The relationship  among  m-cresol
concentration,   chlorine  dosage,  contact  time,  and  chlorine
residual is shown in Table 68.

In related studies, phenol  in  concentrations  of  25  mg/1  was
treated  with  levels of chlorine calculated to provide an excess
of phenol.  Gas chromatographic  analyses  of  samples  withdrawn
after  a  contact  time  of  0.5 hour revealed the presence of 0-
chlorophenol,   p-chlorophenol,    2,6,    dichlorophenol,    2,4
dichlorophenol, and 2,4,6 trichlorophenol.  Similar tests with m-
cresol  showed  the  formation  of a number of reaction products,
which were assumed to be a mixture of chloro-m-cresols.  Positive
identification was not made because chlorine-substituted  cresols
for use as standards are not available commercially.

The   authors   proposed  that  the  reaction  proceeds  in  part
sequentially by the stepwise substitution of the 2,4, and 6  ring
positions, and in part simultaneously, resulting in the formation
of  a  complex  mixture  of  chlorphenols  and  their  oxidations
products.  Ring oxidation was assumed to follow the formation  of
2,4^6  trichlorophenol.   Other  authors have postulated that the
reaction proceeds only by a stepwise substitution.

Burttschell has indicated that  the  progression  of  chlorinated
products occurs as follows:

     Phenol
     2-Chlorophenol
     4-Chlorophenol
     2,4-Dichlorophenol
     2,6-Dichlorophenol
     2,4,6-Trichlorophenol
     4,4-Dichloroquinone
     Organic Acids

Destruction of the benzene ring was found to occur at a chlorine-
to-phenol  ratio  of  10:1.   Burttschell  attributed  the  taste
problem associated  with  chlorophenols  to  2,6-dischlorophenol.
The  development  of taste was reported not to occur at pH values
of less than 7.0.

Results of a study by Eisenhauer supported earlier work of  other
investigators  that non-aromatic products are formed when phenols
are treated with high levels of chlorine.
                              219

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TABLE  68  CHLORINE DEMAND OF M-CRESOL AFTER VARIOUS
                    CONTACT TIMES

m-Cresol Contact
Concentration Chlorine Time
(mg/1) (mg/1) (hr)
0.25
10 20 0.5
1.0
2.0
0.25
10 50 0.5
1.0
2.0
0.25
10 100 0.5
1.0
2.0
0.25
20 50 0.5
1.0
2.0
0.25
20 100 0.5
1.0
2.0

Chlorine
Residual
(mg/1)
3.3
1.5
0.5
0.2
30.8
30.8
28.3
17.0
81.4
77.0
61.6
61.6
16.3
11.1
8.0
8.0
61.6
58.2
56.6
46.0
Net

mg/1

16.7
18.5
19.5
19.8
19.2
19.2
21.7
33.0
18.6
23.0
38.4
38.4
33.7
38.9
42.0
42.0
38.4
41.8
43.4
54.0
Chlorine
Demand
m mol cl?
m mol m-Cresol
2.5
2.8
3.0
3.0
2.9
2.9
3.3
5.0
2.8
3.5
5.9
5.9
2.6
3.0
3.2
3.2
2.9
3.2
3.3
4.1
                             220

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Oxidation   products   resulting   from   the   chlorination   of
pentachlorophenol  have  not  been studied intensively.  However,
Thompson and Dust reported the presence of chloranil  in  samples
of chlorinated waste water analyzed using a gas chromatograph.

with  the  exception  of  the  last  reference cited, the studies
described in the foregoing paragraphs have  dealt  with  phenolic
compounds  in  solutions  not contaminated with other substances.
Because of other chlorine-consuming materials in wood  preserving
waste  water, a question arises concerning the levels of chlorine
required to fully oxidize phenols in  such  wastes.   Unpublished
results  of  a  recent  study   (1970)  at  the Mississippi Forest
Products Laboratory provide a partial answer.

Creosote waste water with phenol and  COD  contents  of  508  and
13,500  mg/  1, respectively, were flocculated and samples of the
filtrate adjusted to pH values of U.5, 7.0, and 9.5.  The samples
were treated with quantities of calcium  hypochlorite  calculated
to  yield  a  gradient series of chlorine concentrations.  The pH
readings of the samples were  adjusted  to  the  original  values
after a contact period of 30 minutes.  After 8 hours, the samples
were  filtered,  analyzed  for  phenols  by  the 4-aminantipyrine
method, and then analyzed for di- and tri-chlorophenols using  an
electron    capture    detector.     Chloro-cresols   and   other
chlorophenols were not included because  reagent-grade  materials
for  use  as standards could not be found.  The results are given
in Table 69.

Trichlorophenol was present in all samples, but the concentration
decreased rapidly with increasing levels of  chlorine.   However,
traces  remained  in  samples  treated with the highest levels of
chlorine.  The rate of  oxidation  was  highest  at  pH  4.5  and
decreased  with  increasing  alkalinity,  although the difference
between pH 7.0 and 9.5 was not great.  The  relationship  between
results  of the APHA test for phenols and levels of chlorophenols
determined using an electron capture detector was generally  poor
at  low  chlorine  levels.  However, low values for the APHA test
always corresponded with low concentrations of chlorophenols.

Ozone Treatments - Ozone is a powerful oxidizing agent,  but  its
employment in waste treatment is a relatively recent development.
Its  principal  disadvantages  are  its  lack of stability, which
requires that it be produced as used, and its high cost  both  in
terms  of  capital  investment  in equipment and operating costs.
The major cost of producing ozone is  electricity.   It  requires
19.8 kwh of electricity to produce one kilogram of ozone with air
feed  to  the  generating equipment and 9.9 kwh with oxygen feed.
The high initial cost of ozonation is offset in part by the  fact
that the equipment has a useful life expectancy of 25 years.

Treatment  of  waste  water  with ozone may be either by batch or
continuous flow methods.  Ozone reacts rapidly  with  phenols  at
all pH levels, but the optimum pH observed by Niegowski was 12.0.
Ozone  demand  at  pH  12  was  less than one-half that at pH 7 in
                              221

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TABLE  69 CHLOROPHENOL CONCENTRATION IN CREOSOTE WASTEWATER
                     TREATED WITH CHLORINE


As
PH

4.5





7.0





9.5






Ca(PCl)2
Chlorine
(8/D
0
0.5
1.0
1.5
2.0
3.0
5.0
0.5
1.0
1.5
2.0
3.0
5.0
0.5
1.0
1.5
2.0
3.0
5.0
Residual
Phenols (mg/1)
by
APHA Method
438.5
256.1
30.8
0.0
0.0
0.0
0.0
300.0
101.5
7.7
0.0
0.0
0.0
315.4
101.5
11.5
0.0
0.0
0.0

ECD Analysis
2-, 4-dichloro-
phenol
—
161.0
9.9
0.0
0.0
0.0
0.0
122.0
0.0
0.0
0.0
0.0
0.0
198.0
0.0
0.0
0.0
0.0
0.0

(mg/1)
2-, 4-, 6-tri-
chlorophenol
—
910.0
6.7
1.5
1.0
0.3
0.3
316.0
35.0
6.4
2.8
1.5
1.3
264.0
27.0
25.0
3.7
3.8
1.9
                            222

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treating petroleum waste  waters.   However,  the  difference  in
demand  was  manifested  only in oxidizing the last 30 percent of
the phenol in the waste.  During two-thirds of the oxidation, the
reaction was so rapid that pH had very little effect.

A ratio of ozone:phenol of about  2:1  normally  is  required  to
destroy the phenols in a solution.  However, ratios as low as 1:1
and  as  high as 10:1 were reported by Niegowski for waste waters
from different sources.  According to  Gloyna  and  Malina,  only
about  I/TO  as much ozone is required as chlorine to oxidize the
same amount of phenol.

Because of its high energy requirements and  the  resulting  high
operating  costs, ozonation does not lend itself to the treatment
of wood preserving waste waters, and hence will not be considered
further in this report,

Activated  Carbon  Filtration  -   Activated   carbon   is   used
commercially  to  treat  petroleum  and other types of industrial
waste waters.  It can also be used effectively to remove phenolic
compounds from wood preserving waste  streams.   Although  carbon
has  a  strong  affinity  for nonpolar compounds such as phenols,
adsorption is not limited  to  these  materials.   Other  organic
materials  in  waste  water  are  also  adsorbed,  resulting in a
decrease in the total oxygen demand of the  waste.   Because  the
concentration of the latter substances exceeds that of phenols in
effluents  from  wood  preserving  plants,  the  useful  life  of
activated carbon is determined  by  the  concentration  of  these
materials and the rate at which they are adsorbed.

Results  of  carbon-adsorption  studies  conducted  by  Dust  and
Thompson on a creosote  waste  water  are  shown  in  Figure  42.
Granular  carbon was used and the contact time was 24 hours.  The
waste water was flocculated  with  ferric  chloride  and  its  pH
adjusted to 4.0 prior to exposure to the carbon.  As shown in the
figure,  96 percent of the phenols and 80 percent of the COD were
removed from the waste water at a carbon dosage of  8  g/1.   The
loading  rate  dropped  off sharply at that point, and no further
increases in phenol removal  and  only  small  increases  in  COD
removal  occurred by increasing carbon dosage to 50 g/1.  Similar
results were obtained  in  tests  using  pentachlorophenol  waste
water.

Results    of    adsorption    isotherms   that   were   run   -on
pentachlorophenol waste water,  and  other  samples  of  creosote
waste  water  followed  a pattern similar to that shown in Figure
42.  In some instances a residual content of  phenolic  compounds
remained  in  waste water after a contact period of 24 hours with
the highest dosage of activated carbon employed, while  in  other
instances all of the phenols were removed.  Loading rates of 0.16
kg  of  phenol and 1.2 kg COD/carbon were typical, but much lower
rates were obtained with some waste waters.

Other Process Waste Water Handling Methods
                              223

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   100
(0
s
Q>
CC
Q.
•o
C
(Q
O
o
o
                   Activated  Carbon (gm / liter)
  FIGURE 42
RELATIONSHIP BETWEEN WEIGHT  OF ACTIVATED
CARBON ADDED AND REMOVAL  OF  COD AND PHENOLS
FROM A CREOSOTE WASTEWATER
                          224

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Containment arid Spray Evaporation  -  Forty-two  percent  of  the
plants  responding  to  the  survey  referred  to  in  Section  V
indicated that they currently are storing their  waste  water  on
company  property,  and  therefore  have no discharge (Table 44).
The popularity of this method of waste  handling  undoubtedly  is
attributable  to  its  low cost, in the case of plants with ample
land area, and its simplicity.  The practicality of the method is
questionable in areas of high rainfall and low evaporation  rate,
unless the rate of evaporation is increased by the application of
heat or by spraying.  The latter alternative is being employed by
a number of plants in the Gulf coast region of the South.

The  use  of spray ponds to dispose of waste water by evaporation
requires that a diked pond  of  sufficient  .capacity  to  balance
annual  rainfall  and  evaporation  be  constructed.  The pond is
normally equipped with a pump and the  number  of  spray  nozzles
necessary to deliver to the air the volume of water calculated to
provide  the  desired  amount  of  evaporation,  assuming a given
evaporation efficiency.

The  feasibility  of   spray   evaporation   depends   upon   the
availability of a land area of such size that a pond large enough
to  permit  a  balance  between  inflow  and  evaporation  can be
constructed,  pond size and number of spray heads are  determined
by waste volume and the ratio of rainfall to surface evaporation.
Where  rainfall  and  evaporation  in  a region are approximately
equal, the effect of both can be neglected, if sufficient storage
capacity is provided.  For areas with higher annual  rainfall  or
lower  evaporation rate, the design of a spray evaporation system
must account for a net annual increase in  water  volume  in  the
pond due to rainfall.

Pan  Evaporation - A few plants with small volumes of waste water
are evaporating it directly by application of  heat.   Basically,
the  procedure  involved is to channel the effluent from the oil-
separation system into an open vat  equipped  with  steam  coils.
The  water  is then vaporized by boiling, or, as in one instance,
heated to approximately 71°C  (160°F) and the rate of  evaporation
increased  by circulation of air across the surface of the water.
The method is expensive, and is based on  using  natural  gas  as
fuel,  assuming  an  overall  efficiency  of  65  percent for the
process.


Evaporation in Cooling Towers - In this  process,  effluent  from
the  :oilseparation system is discharged to the basin of a cooling
tower and reused as cooling water.  Normal evaporation associated
with the operation of the tower accounts for an average  loss  of
approximately  7,570  I/day   (2000  gal/day) for a typical tower.
Evaporation of excess water  is  expedited  by  the  intermittent
operation  of  a  heat  exchanger  or  other  heating  system  in
conjunction with a fan.  The efficiency of the  condensers,  both
tube  type and barometric, are reported to be unaffected by water
temperatures of up  to  38°C   (100°F)  and  by  light  oils  that
                              225

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accumulate  in the water.  The owner of one plant stated that oil
concentrations as high as 10 percent could be  tolerated  in  the
cooling  water.  However, problems with condenser efficiency were
reported at another plant in which the oil content of the process
water used for cooling was less than 100 mg/1.

Incineration - Two plants  in  the  U.S.  are  known  to  operate
incinerators  for  waste water disposal.  The one plant for which
data are available currently operates a unit capable of "burning"
5,676 1/hr {1500 gal/hr)  of waste water.   Fuel  cost  alone  for
this  unit,  which  is fired with Bunker C oil, is $15.00/3,785 1
(1000 gal) of waste.

Data  reported  by  the  American  Wood  Preservers'  Association
indicates  that  incineration  of  waste water is economical only
when the oil content of the waste is 10 percent or higher.   Such
high  oil  contents  are not common for waste water from the wood
preserving industry.

Required Implementation Time

Because of the relatively small volume of  waste  water  at  most
wood   preserving   plants,   "off-the-shelf"   equipment  should
ordinarily meet the requirements of the  individual  plants  with
regard  to the application of treatment technology required to be
achieved by July 1, 1977 and July 1, 1983, respectively.   It  is
not  anticipated,  therefore, that either equipment availability,
or  (because of the simplicity of the equipment)  availability  of
construction  manpower will seriously affect implementation time.
For the same reason, it is not anticipated that the time required
to construct new treatment facilities  or  modify  existing  ones
will  affect  implementation  time  for  any of the treatment and
control technologies that  are  likely  to  be  employed  in  the
industry.

Land  availability  will  influence  the  choice of treatment and
control technology at many  wood  preserving  plants  located  in
urban  areas.   For  example,  the employment of oxidation ponds,
soil  irrigation,  and  possible  aerated  lagoons  will  not  be
feasible in areas where all company land is in use and additional
acreage  cannot  be purchased at a reasonable price.  Plants thus
located will have to select  other  treating  methods,  the  land
requirements of which conform to the space that is available.


Effect of Treatment Technology on Other Pollution Problems - None
of  the  treatment  and  control  technologies that are currently
feasible for use in the wood preserving segment of  the  industry
will have an effect on other pollution problems.

Solid  Waste  - Solid wastes resulting from treatment and control
technologies that have  potential  use  in  the  wood  preserving
industry  are  of  two  types:   sludge from coagulation of waste
water  and  bacterial   sludges   originating   from   biological
                              226

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treatments.   The  former  material  contains  oil  and dissolved
phenolic compounds originally in the preservative, along with the
flocculating  compound  used.   In  the  case  of   water-soluble
preservatives,  the sludge will contain traces of the metals used
in the particular  preservative  or  fire  retardant  formulation
involved.   Bacterial sludges contain the biomass from biological
treatments, but are of importance from the standpoint of disposal
only in the case of treatments that employ activated  sludge  and
trickling filter units.

The  volume  of sludge involved with both types is small.  Plants
currently are disposing of these materials in sanitary landfills.
Incineration of organic waste and burial of inorganic  salts  are
possible disposal methods that could be used.

Plant Visits

A  number  of  wood  preserving  plants judged to be exemplary in
terms of their  waste  management  programs  and  practices  were
visited  in conjunction with this study.  Selection of plants for
visits was based on the type of  waste  water  treating  disposal
system  employed  or  both,  and, insofar as possible, geographic
location.  Plants that dispose of their raw waste by  discharging
it  to  a  sewer  were  not represented among the plants visited.
Exclusion of these plants limited the  number  considered  for  a
visit to the approximately 30 plants in the U.S. that either give
their  waste  the  equivalent  of  a  secondary  treatment before
discharging it, or which have no discharge,  only  four  of  this
number were found both to treat their waste on site and discharge
it  directly  to  a  stream.   The remainder either channel their
treated water to an irrigation field or to a sewer,  or  have  no
discharge because of reuse of waste water, evaporation, or both.

Plant  visits  were used to obtain samples, the analyses of which
permitted an evaluation of the  efficiency  of  the  waste  water
treating  system  employed.   Performance  data  provided  by the
plants themselves were used in this  evaluation  when  available.
Information  was  also  obtained on flow rate, annual production,
and other parameters  needed  for  the  development  of  effluent
guidelines.   Cost  data  on  waste  water  treating systems were
requested of all plants and provided by some.


A summary of the data obtained for each plant visted is presented
in Table 70.  Flow diagrams illustrating waste treatment  systems
employing  extended  aeration,  soil percolation, and combination
aerated lagoon and oxidation pond are shown in  Figures  43,  44,
and 45 respectively.
                              227

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PCP
                                            Secondary PCP
                                            ft Creo. Separation
                      Catch   Pond
                  Overflow and Run-off Water
                                 Holding Ponds

                                Final Separation
                          WASTEWATER FLOW DIAGRAM FOR
                          A  WOOD-PRESERVING  PLANT EM-
                          PLOYING AN OXIDATION POND  IN
                          CONJUNCTION WITH AN AERATED
                          RACEWAY

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                 TABLE  70  SUMMARY  OF WASTEWATER CHARACTERISTICS FOR 17 EXEMPLARY WOOD PRESERVING PLANTS
ro
OJ
Plant
No,
1
2*
3
4*
5
6
7
8
9
10
11
12
13
14
15
16
17J 	 j
Average
Phenol
(mg/1)
6.00
0.00
0.50
35.96
—
—
3.30
0.40
—
—
—
—
—
—
—
—
2.50
2.50
COD
(mg/1)
845
10
10
1695
—
—
523
435
—
—
—
—
—
—
—
—
240
240
Oil and
Grease
(mg/D
7
7
0
83
—
—
55
158
—
—
—
—
—
—
—
—
12
46
Suspended
Solids
(mg/1)
100
253
60
724
—
—
103
270
—
—
—
—
—
—
—
—
82
123
Volume
of
Effluent
,' Ipd)
73,800
49,200
49,200
34,100
3,800
34 , 100
567,800
98,400
15,100
22,700
49,200
18,900
4,700
9,500
7,600
19,700
63,200
34,600
Volume
of
Discharge
(Ipd)
0
0
0
0
0
0
492,100
87,100
0
0
49,200
0
0
0
0
0
63,200
—
Daily
Produc-
tion
(cu m)
283
283
266
436
210
403
708
425
178
204
93
210
62
125
34
190
223
255
Cost
($)
42,000
90,000
30,000
17,000
40,000
25,000
85,000
46,000
38,000
85,000
—
120,000
5,500
6,000
50,000
39,000
—
47,900
Final
Disposition
of
Waste
Sewer
Field
Field
Field
Field
Field
Stream
Stream
Pond
Evaporated
Ditch
Evaporated
Evaporated
Evaporated
Evaporated
Sewer
Stream

            *Data not  included  in average.

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                          SECTION VIII

           COST, ENERGY, AND NON-WATER QUALITY ASPECTS

BARKING

Cost  and Reduction Benefits of Alternative Treatment and Control
Technologies

Only wet barking techniques result in any  discharge  of  process
waste  waters.  An elimination of the discharge of pollutants can
be accomplished by all but hydraulic barkers through the  recycle
of process water.


A  hydraulic  barking  operation  servicing a 9.3 million sq m/yr
will typically have a waste load  of  about  13,100  kg/day   (100
million  sq  ft/yr) plant (28,800 Ib/day) of suspended solids and
660 kg/day (1,450 Ib/day) of BOD5, and a  flow  of  approximately
6500  cu  m/day  (1.73 million gal/day).  Recycle of this effluent
has not been shown to be practicable technology.  In the pulp and
paper industry, however, hydraulic barker  effluent  is  commonly
treated biologically along with other waste waters.

One  hydraulic  barker  such as the one presented here can handle
the barking operation of mill producing 9.3  million  sq  m   (100
million sq ft/yr) of plywood on a 9.5 mm  (3/8 in) basis.

Alternative A;  No Waste Treatment or Control

Effluent waste load is estimated at 660 kg/day of BOD5_ and 13,100
kg/day of suspended solids for the selected plant.

          Costs:  None
          Reduction Benefits:  None

Alternative B_:  Clarification and Biological Treatment

This  alternative includes clarification of waste waters and then
combination with  other  wastes  for  biological  treatment.   An
activated  sludge system can achieve 95 percent BOD5 removal with
a resulting effluent load of 35.0 kg/day  (77 Ib/day)  for  a  100
million sq ft/yr plywood on 3/8 in basis plant.

             INVESTMENT AND OPERATING COST ESTIMATE
                          ALTERNATIVE B

             Clarification and Biological Treatment

.Item                                                 Cost

1.  Installed Equipment                         $1,070,500
2.  Yearly Operating Costs                          138,200
                              233

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             TOTAL COST/YR                      $  196,300

VENEER AND PLYWOOD MANUFACTURING SUBCAT.EGQR1ES
          Reduction Benefits of Alternative Treatment And Control
Technologies For A Selected Plant

The typical combination  veneer  and  plywood  mill  selected  to
represent   the  veneer  and  plywood  subcategories  is  a  mill
producing 9.3 million sq m/yr on a 9.53 mm basis  (100 million  sq
ft/yr on a 3/8 in basis) .  It is assumed to have the following:

          (1)  Log conditioning by means of hot water
              vats with direct steam
              impingement and a resulting discharge;
          (2)  No containment of dryer washwater;
          (3)  A phenolic glue system without recycle
              of washwater.

This  is a hypothetical mill and is not typical in the sense that
it represents the average mill.  It  is  typical  of  a  softwood
plywood  mill  built  in  the  past twenty years, but without any
degree of waste water treatment and control.   This  hypothetical
plant might be located in a number of places throughout the U.S.,
however,  it  is  more  likely  that  it  will  be located in the
southeast because of the fact that hot water vats are used.
A single mill has been chosen to represent both  the  veneer  and
plywood  subcategories, as the two manufacturing operations often
take place in the  same  plant,  and  the  costs  would  thus  be
applicable to a combination operation.  In a plant producing only
plywood, however, only the costs of alternative treatment B  (glue
wash water recycle) would apply.

Basis of. Assumptions Employed In Cost Estimation

Investment  costs  are based on actual engineering cost estimates
as described in the following paragraph.

Yearly operating costs  are  based  on  actual  engineering  cost
estimates   using   $7.00/hr  for  salaries  and  $0.01  kwh  for
electricity.  The annual  interest  rate  for  capital  cost  was
estimated at 8%.  Salvage value was set at zero over  20 years for
physical facilities and equipment.  The total yearly  cost equals:
(investment  cost/2)  X   (0.08)  +  (investment  cost) X  (0.05) *
yearly operating cost.
                              234

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Alternative A:  No Waste Treatment Or Control

Effluent waste load is estimated  at  485  Kg/day  of  BOD   (1080
Ib/day) for the selected plant.

          Costs:  None
          Reduction Benefits:  None

Alternative B:  Complete Retention of Glue Washwater

This   alternative  includes  complete retention of glue wastes by
recycle and reuse in glue preparation.   This  practice  has  now
become  standard in the industry although four years ago only one
mill   practiced  complete  recycle.   Collection,  holding,   and
screening  is  now practiced in 60 percent of the mills surveyed.
In 1972, 50 mills practiced recycling and  it  is  believed  that
more than 50 percent of the softwood plywood mills now recycle or
plan  to recycle glue wash water.  BOD waste load is estimated at
410 kg/day  (900 Ib/day) for the selected typical  plant  at  this
control level,

Recycling  of  glue  wash water is the most significant pollution
control step in the reduction  of phenolic compounds; free phenols
are reduced by 73 percent.  Associated costs for a 9.3 million sq
m/yr plant on a 9.53 mm basis  (100 million sq ft/yr on a  3/8  in
basis) are described below.

                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE B

Item                                                 Cost

1.  3785 1  (1000 gal)  concrete sump                $ 1,300
2.  18925 1  (5,000 gal) holding tank                 1,000
3.  1080 1  (285 gal) pressure  tank                     350
4.  Rotating screen                                  1,800
5.  Pumps                                            3,700
6.  Valves, fittings,  controls and
                        engineering costs       	9. 350
                                 TOTAL COST        $17,500
                      OPERATING  COST  ESTIMATE

 Item                                             Cost

 1.  Operation  and Maintenance                 $  2,200
 2.  Electricity                             	800 rii
                             TOTAL  COST/YR    $  3,000

 Summary:
          Costs:  Incremental costs  are approximately
                  $17,500  over  Alternative  A, thus
                  total  costs are  $17,500.
                              235

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          Reduction Benefits:  An incremental reduction
                  in plant BOD is approximately 77 kg/day
                  (170 Ib/day).  Total plant reduction in BOD
                  would be 15.8 percent.


Alternative  C:   Complete  Retention  of  Waste  Water  From Log
Conditioning

Alternative C would result in complete recycle of water from  hot
water vats with containment of excess waste waters.  Modification
of  hot  water vats to provide heat by means of coils rather than
direct steam impingement is assumed.

                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE C

Item                                              Cost

1.  320 cu m (85,000 gal)  settling tank         $ 1,900
2.  Pump and motor                                1,300
3.  Containment pond, 30.5 m x 30.5 m
    (100 ft x 100 ft)                             4,300
4.  Piping, contingencies and labor               4,500
                             TOTAL COST         $12,000

                     OPERATING COST ESTIMATE
                          ALTERNATIVE C

Item                                              Cost

1.  Operation and Maintenance                   $ 6,300
2.  Electricity                                   2.200
                              TOTAL COST/YR     $ 8,500

Summary
          Costs:  Incremental costs of approximately
                  $12,000 over Alternative B would be
                  incurred, thus producing total costs
                  of $29,500.
          Reduction Benefits:  An incremental reduction
                  in plant BOD of 406 kg/day  (894 Ib/day)
                  is evidenced when compared to
                  Alternative B.  Total plant reduction
                  in BOD is 99.3 percent.

Alternative D:  Complete Retention of Dryer Wasnwater

Alternative D would result in the  complete  retention  of  dryer
washwater.   Modification  of  washing  operations  to reduce the
volume of water used assumes  reduction  of  water  by  scraping,
pneumatic  cleaning  and general water conservation with complete
retention of waste water by irrigation or  containment  on  site.
Effluent  waste  load  is  estimated  at  0 kg/day of BOD for the
                               236

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selected typical plant at this control level.   Complete  control
of wastes without discharge to receiving waters is effected.

                    INVESTMENT COST ESTIMATES
                          ALTERNATIVE D

Alternative p-1; Spray Irrigation.
Associated Costs:

Item                                          Cost

1.  37850 1 (10,000 gal) storage tank       $ 2,700
2.  Pump and motors                           1,200
3.  Piping                                    2,600
4.  Labor and contingencies                   3,200
                           TOTAL COST      ~$ 9,700

Alternative P-2 - Containment by Lagooning

A conservative estimate of 76.2 cm/yr  (30 in/yr) of evaporation
is assumed.

Item                                    -   Total Cost

30.5 m x 30.5 m pond                        $ 4,300


                    OPERATING COST ESTIMATES
                          ALTERNATIVE D

Item                                      Cost

1.  Operation and Maintenance            $ 7,900
2.   Electricity                           2,300
                         TOTAL CQST/YR   $10,200

Summary:


          Costs:  Investment'costs of $5,000 to $10,000
                  over Alternative c would be incurred,
                  thus producing total costs of about
                  $37,000  ($35,000 to $40,000).
          Reduction Benefits:  An incremental reduction
                  in plant BOD of 3 Jcg/day  (6 Ib/day) is
                  evidence when compared to Alternative C,
                  producing a total plant reduction in BOD  discharge
                  of 100 percent.

                  SUMMARY OF ALTERNATIVE COSTS

                BOD      Investment     Yearly         Total  Yearly
Alternative   Removal 	  cost  	   Operating   	     Cost 	
                              237

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     A
     B
     C
     D
   OX
 15.8%
 99.3%
100.0%
0
17,500
29,500
37,000
   0
   3,000
   5,000
   7,700
             0
             4,575
             7,655
             9,030
                          TABLE 72

       SUMMARY OF HASTE LOADS FROM TREATMENT ALTERNATIVES  (kg/day)
BOD

TSS
RWL
485
352
A
485
352
B
412
330
C
3
11
D
C
0
Phenols
        0.25
  0.25
0.09
0.07  0
    HARDWOOD VENEER AND PLYWOOD MANUFACTURING CONSIDERATIONS

Hardwood  veneer  and  plywood  manufacture  normally occurs at a
plant considerably smaller in size than a softwood  manufacturing
facility.    As   discussed  above,  the  softwood  plant  has  a
production rate of about 9,290,000  sq  m/year   (1000,000,000  sq
ft/yr) whereas a hardwood veneer and plywood mill of average size
will  produce  about  464,500 sq m/year  (5,000,000 sq ft/yera) of
veneer and plywood.

Because of the  significantly  lower  production   (or  throughput
rate)  less  water is used and as a result, treatment and control
schemes necessary to reduce or eliminate the discharge  of  waste
water  pollutants are on a smaller scale than those applicable to
waste waters generated by a softwood manufacturing facility.

Presented below in tabular  format  is  information  showing  the
pollutants  generated,  the  pollutant  reduction  achievable  by
application of technology and the  costs  associated  with  these
technologie s.
RAW WASTE
Conditioning
 Vats

Dryer
 Washwater
Flow Waste Load
LI m/day
(mgd)


0.043
(0.0115)
0.429
(0.000 14)
Concentration
mg/1
BOD

700

750

SS

600

3000

Loading,
kg/ day
(Ib/day)
BOD SS
30 26
(67) (58)
0.4 1.6
(0.9) (3.5)
                              238

-------
TREATMENT                 Investment    Yearly    TOTAL       BOD
                           Cost       Operating   Annual     Removal
                           <$)           <$>           <$)
Conditioning Vats
  Lagoon                3,000          600         870         30
  Activated Sludge     32,500        8,500      11,025         90

Glue Wash Water
  Recycle System        2,000          300         480        100

Dryer Wash Water
  Lagoon                   50           50          50         32


As  can be seen from the information presented in the table above
it is, from an economic viewpoint, more feasible  to  modify  the
manufacturing  procedures  to  accomplish  the elimination of the
discharge  of  pollutants  than  it  is  to   install   treatment
technologies to reduce the level of discharge.
Mills With Existing Steam Vats

In  Sections  I,  II,  and  IX  of  this  report,  a  variance is
recommended for mills with existing steam vats.  In Section  VII,
it is noted that existing technology for treatment and control of
waste  waters  from  steam  vats consists of biological treatment
which is capable of  85  to  90  percent  removal  of  BOD.   Two
modifications  of  steam  vats   (modified  steaming and hot water
sprays)  which make zero discharge feasible are also discussed  in
Section  VII.   These modifications will not be required for best
practicable control technology as defined by the Act.
As discussed in Section VII, biological treatment  is  applicable
to waste waters from steam vats.  A summary of costs and effluent
levels  for  biological treatment of waste waters from mills with
existing steam vats is presented below;

     1.  A system consisting of a vacuum separator
     followed by an aerated lagoon would cost
     approximately $81,000 for the selected
     mill utilizing a steam vat and
     would reduce the load to around 41 kg/day
     (90 Ib/day) of BOD.

     2.  An activated sludge plant may result in
     slightly higher BOD removals for a cost of
     about $138,000 and a resulting BOD discharge of
     about 20 kg/day (45 Ib/day) for the
                              239

-------
     selected mill.

Related Energy Requirements of Alternative Treatment and  Control
Technologies

It  is  estimated  that  180  kwh  of  electricity is required to
produce 93 sg m  (1000 sq ft) of plywood.  This electrical  energy
demand  is  affected by the following factors:  (1) type of wood,
(2) whether or not logs are conditioned,  (3) type of  dryer,  and
(4) amount of pollution control devices.

For  a typical mill producing 9,3 million sq m/yr  (100 million sq
ft/yr)  of plywood on a 9.53 mm  (3/8 in) basis,  total  energy  is
estimated  at 4500 kw.  At a cost of one cent/kwh the plant would
have a yearly energy  cost  of  $180,000.   Associated  with  the
control   alternatives   are  annual  energy  costs.   These  are
estimated to be:

     For Alternative A:  $0
     For Alternative B:  $800
     For Alternative C:  $900
     For Alternative D:  $1000

Nonwater Quality Aspects of  Alternative  Treatment  and  Control
Technologies

Air  Pollution;   While  there  are  no appreciable air pollution
problems associated with any of the -treatment and control  alter-
natives, in veneer and plywood manufacturing operations there are
air  pollution  problems  presently  in  existence that may cause
water pollution problems.  The main source of  air  pollution  is
from the veneer dryers as the stack gases from the dryers contain
volatile organics.

Veneer  Dryers:   Since  there  are currently no emission control
systems installed on any veneer dryers, it  is  not  possible  to
cite  typical  applications or technology.  There are, of course,
methods operating on similar processes which  would  be  suitable
and applicable for controlling emissions from veneer dryers.

If particulate emissions were excessive, they could be adequately
controlled  by  utilizing  inertial  collectors of the cyclone or
mechanical type.  Volatile and condensable hydrocarbon  emissions
could  be  effectively controlled by one of the several following
methods:

          (1)  Condensation, utilizing tube con-
               densers with air or water for cooling.
          (2)  Absorption  (scrubbing) , utilizing
               water or a selective solvent.
          (3)  Incineration or thermal oxidation.
          (4)  Adsorption
          (5)  A combination of the above.
                              240

-------
The water pollution potential of these control  methods  are  not
great.  Only condensation and scrubbing use water.  Water used in
condensation  is  only  cooling  water and thus not contaminated.
The most efficient scrubber appears to be that using a  selective
solvent  rather  than  water for absorption.  Scrubbing water can
usually be recycled.


Odors:  Odors presently associated with veneer  and  plywood  are
not  considered to be a pollution problem.  Since the control and
treatment technology of this industry  is  greatly  dependent  on
containment  ponds,  there is always the danger of ponds becoming
anaerobic.  Frequently anaerobic ponds  will  promote  growth  of
organisms which biochemically reduce compounds to sulfur dioxide,
hydrogen sulfide and other odor causing gases.

Solid waste;  The bulk of the solid waste from veneer and plywood
mills  is  comprised of wood residues and bark.  These wastes are
commonly used as fuel in the boiler.

In addition  to  wood  wastes  are  the  settleable  solids  that
accumulate  in  ponds  and  those that are separated in screening
devices.  Disposal of this material may be at the plant  site  or
the  waste  material  may  be collected by the local municipality
with disposal by landfill.  While the amount of solids  generated
is  not  expected  to  be great/ consideration must be given to  a
suitable site  for  landfill  and,  in  turn,  to  protection  of
groundwater supplies from contamination Isy leachates.
HARDBOARD - DRY PROCESS
Cost  and Reduction Benefits of Alternative Treatment and Control
Technologies


The following cost estimates are based  upon  actual  preliminary
cost  estimates  for a waste treatment system for the dry process
industry.  The waste water volume from this industry is  low  and
the   major approach for further reducing waste flow is by inplant
modifications  and  changes  in  inplant  procedures.   The  mill
selected  to  represent  the dry process hardboard industry has a
production of 227 kkg/day  (250 ton/day), and a waste  water  flow
of  945  I/day   (250 gal/day).  The waste water discharges result
only  from caul washing.  The basic results are summarized in  the
paragraphs below.
                              241

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Basis o£ Assumptions Employed in Cost Estimates

Investment  costs are based on actual engineering cost estimates.
Yearly operating costs are based on  engineering  cost  estimates
using  $10.00/hr for salaries, $0.01 kwh for electricity and 1973
market cost for chemicals.  Annual interest rate for capital cost
is estimated at 856,  a salvage value of zero over  20  years  for
physical   facilities   and   equipment,   and  a  straight  line
depreciation cost are assumed.  The  total  yearly  cost  equals:
(investment  cost/2)  X   (0.08)   +   (investment  cost)  X (0.05) +
yearly operating cost.

Alternative A;  No Waste Treatment or Control

Effluent consists of 945 I/day (250 gal/day) of. caul wash  water.
There  is  no  log  or chip wash, no resin wash water, humidifier
water or housekeeping water discharge.

          Costs:  None
          Reduction Benefits:  None

Alternative B:  Retention of Caul Washwater

This alternative includes the collecting of caul washwater  in  a
holding   tank   and   trucking   to   land   disposal  after  pH
neutralization.  There are no provisions in  the  following  cost
estimates  for  handling water from fire fighting.  As the number
of fires and  the  amount  of  water  used  vary  so  widely,  no
estimation  was made for handling this potential source of water.
There are new techniques being  developed  to  limit  the  oxygen
concentrations  in  the  air stream which will greatly reduce, if
not eliminate, future fire problems in the dry process  hardboard
industry.

                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE B

Item                                                    Cost
                                                     .(May, 1973)

1.  18,925 1  (5,000 gal) storage tank
    (includes installation and fittings)             $  4,000
2.  1892 1  (500 gal) storage tank  (acid resistant)
    (includes installation and fittings)                 1,500
3.  Chemical feed pump                                    500
4.  Pumps and piping                                    6,000
5.  Instrumentation (pH) and controls                   1,000
6.  Chemical mixer                                        500
7.  Tank Truck 7570 1 (2,000 gal)                       8,500
8.  Land                                                3,000
                                  TOTAL               $25,000
                              242

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                    OPERATING COST ESTIMATE
                          ALTERNATIVE B
Item
1.  Labor (4 man hr/wk)
2.  Electricity
3.  Chemicals
4.  Maintenance
          Costs:
                                                        Cost

                                                     $ 2,080
                                                          65
                                                         500
                                                         355
                                TOTAL COST/YR
                                                     $ 3,000
                  Incremental costs are approximately
                  $21,500 over Alternative A, thus total
                  costs are $21,500.
          Reduction Benefits:  Elimination of caul wash-
                  water as a discharge stream.

Factors Involved In The Installation Of Treatment

The  only  treatment  system  involved  in the representative dry
process mill is the disposal of caul wash  water  by  hauling  to
land  disposal.  There are no problems concerning the reliability
of the system as caul wash water will be put into a storage tank,
neutralized, then hauled by  truck  to  a  disposal  area.   This
system  is not sensitive to shock loads, and startup and shutdown
procedures do not cause a problem.  This system can  be  designed
and  installed  within one year and requires little or no time to
upgrade operational and maintenance practices.  There are no  air
pollution,  noise,  or radiation effects from the installation of
this treatment system.  The quantities of solid  waste  generated
from  this  system are insignificant as are the additional energy
requirements.

HARDBOARD-WET PROCESS

Basis Of Assumptions Employed In Cost Estimation

Investment costs are based on actual engineering cost estimates.

Yearly operating costs  are  based  on  actual  engineering  cost
estimates   using   $10,00/hr   for  salaries,  $0.01  Jcw/hr  for
electricity and present market cost for  chemicals.   The  annual
interest  rate  for  capital  cost  is  estimated to be Q%r and a
salvage value of zero over 20 years for physical  facilities  and
equipment,  and straight line depreciation cost are assumed.  The
total  yearly  cost  equals   (investment  cost/2)    (0.08)   plus
(investment cost)  (0.05) plus yearly operating cost.
  .    and Reduction Benefits of Alternative Treatment and Control
Technologies

The mill selected to represent the wet  process  industry  has  a
production  of  127 kkg/day  (140 tons/day) , a waste water flow of
1,432 cu m/day(0.378 million gal/day),  a  BOD  of  33.75  kg/kkg
                              243

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production  (67.5 Ib/ton) f and a suspended solids concentration  of
9  Jcg/kkg   production   (18  Ib/ton) .   The  results  of  the cost
estimates are shown below.

Alternative A:  Screening and Primary Clarification

Raw waste water characteristics for the typical mill having a BOD
of 33.75 kg/kkg production  (67.5 Ib/ton) represents a  mill  with
recirculation but no inplant treatment facilities.

                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE A
                        Primary Treatment
Item
1.  Drum Screen, installed
2.  Clarifier - 7.6 m diam  x 3.05 m deep
     (25 ft diameter - 10 ft deep)
3.  Sludge Pond - 0.405 ha - 2.44 m deep
     (1 ac - 8 ft deep)
    with liner - including land  cost
4.  Alum System
5.  Miscellaneous
                             Subtotal
                      Cost
                   (May 19731

                    $ 8,000

                    36,000
                    43,000
                    10,000
                    10,000
                  $107,000
20% Engineering and
Contingencies       22,000
TOTAL COST        $129,000
                     OPERATING  COST  ESTIMATE
                           ALTERNATE A

                        Primary Treatment
Item

1.  Manpower
2.  Electricity
3.  Steam
4.  Water
5.  Chemicals
6.  Maintenance
Summary:
                       TOTAL COST/YR
                     Cost

                   $ 8,000
                     2,000


                    18,000
                     3,000
                   $31,000
          Costs:   $129,000
          Reduction  Benefits:   A BOD reduction of 3.4 kg/ ton (ten
                   percent)  and a suspended solids re-
                   duction of  6.8 kg/kkg (75 percent)  would result.
                               244

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Alternative B-l;  Addition of Activated Sludge Process

This  alternative  includes  the  addition of an activated sludge
process including pH adjustment  and  nutrient  addition  to  Al-
ternative  A.   The  effluent  from this system would average 3.4
kg/kkg (6.8 Ib/ton) BOD and 2.25 kg/kkg  (4.5  Ib/ton)  suspended
solids.
The  excess  water  is taken from the process water chest and put
through  a  rotating  drum  type  screen  to  remove  the  larger
particles  of  fiber and suspended solids.  The filtered effluent
is discharged to the feed  well  of  a  primary  clarifier.   The
underflow  is  pumped  to  a  sludge digester.  A portion of this
sludge may be returned to the process water  chest.   The  sludge
from the sludge disgester is pumped to a holding lagoon.

The  overflow  from  the  primary clarifier is discharged into an
activated sludge system consisting of an aerated lagoon  followed
by  a  secondary  clarifier.   The  underflow  from the secondary
clarifier is transferred to the sludge digester and the  overflow
is discharged to waste.
                                                                 \

                    INVESTMENT COST ESTIMATE
                         ALTERNATIVE B-1

             Primary Treatment with Activated sludge

Item                                                  Cost
                                                    (May 1973)

1.  Primary Treatment                              $130,000
2.  Activated Sludge                                503.000
                TOTAL COST                         $633,000 *

*Includes 20% for engineering and contingencies

                     OPERATING COST ESTIMATE
                         ALTERNATIVE B-1

             Primary Treatment with Activated sludge

Item                                                  Cost

1.  Manpower                                      $233,000
2.  Electricity                                     28,000
3.  Steam
4.  Water
5.  Chemicals                                       29,000
6.  Maintenance                              	24.000
             Yearly Costs                         $314,000

Alternative B-2:  Addition of Aerated Lagoon to Alternative A
                              245

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Here,  -the excess water is taken from the process water chest and
put through a rotating drum type  screen  to  remove  the  larger
particles  of  suspended fiber and solids.  The filtered effluent
is discharged into the feed well of a clarifier.

The under flow from the clarifier is pumped to a  0.405  ha  (one
acre)  pond  for  sludge dewatering.  A portion of this sludge is
returned to process.  The clarifier overflow is  discharged  into
an  aerated lagoon for 20 days retention and the aerated effluent
is transferred into a lagoon of 5 days retention time.   Effluent
from the 5 day lagoon is discharged to the environment.
                              246

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                    INVESTMENT COST ESTIMATE
                         ALTERNATIVE B-2

             Screen, Clarifier, and Aeration Lagoon
Item

1.
2.

3.

4.
5.
6.
    Rotating Drum Screen installed
    Glarifier 7.6 m diam x 3.05 m depth
    25 ft diam - 10 ft depth
    Sludge Pond - 0.045 ha - 3.05 m depth
    (1ac - 10 ft depth   )
    Aerated Lagoon - 20 day retention
    Lagoon - 5 day retention
    Miscellaneous  ,
                       Subtotal
                       20% Engineering and
                       Contingencies
                           TOTAL

                     .OPERATING COST ESTIMATE
                         ALTERNATIVE B-2
  Cost
 (May 1973)

 $ 8,000

  36,000

  41,000
 225,000
  50,000
	40,000
 $400,000

  80yOOQ
 $480,000
Item

1.  Manpower
2.  Electricity
3.  Steam
4.  Water
5.  Chemicals
6.  Maintenance
                                                      Cost

                                                 $ 87,000
                                                   21,000
                                                   29,000
                                                   24.000
                TOTAL COST/YR
                                                 $161,000
Summary:
          Costs:  Incremental costs  are  approximately
                  $435,000 over Alternative A, thus  the
                  total  costs are  $544,000.

          Reduction Benefits:  A BOD reduction of  27 kg/kkg
                   (90 percent) and a suspended
                  solids increase  from 200 mg/1  to 250 mg/1
Alternative
                Addition of An Aerated  Lagoon  Treatment  System to
the Activated Sludge Treatment  (B-11 .
— -w^» *— ^«-^v^B«*^W-W^ ^W-^^B-^B^^^— ^••^••i • I • ^—^m***-^l£ ^»— * A_X_^^

This  alternative   includes  the addition of  a  five day detention
time  aerated  lagoon   to the  preceding   treatment  system   in
Alternative  B.   The effluent from  this system would average 1.6
kg/kkg  (3.2 Ib/ton) BOD and  2.8 kg/kkg  (5.6 Ib/ton)  of  suspended
solids.   The  excess water  is taken from the process water chest
                               247

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and put through a rotating drum type screen to remove the  larger
particles  of  fiber and suspended solids.  The filtered effluent
is discharged into the feed well of a clarifier.  Underflow  from
the  clarifier  is  pumped to a sludge digester with a portion of
this flow returned to the process water  chest.   Supernate  from
the  sludge  digester  is  transferred  to a lagoon.  The primary
clarifier overflow is treated toy  the  activated  sludge  process
consisting of an aerated lagoon and a secondary clarifier.  After
activated sludge treatment, the processes effluent is transferred
to  a  secondary  aeration  lagoon  where  after  treatment it is
discharged to waste.

                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE C

      Primary Treatment, Activated Sludge, Aeration Lagoon


Item                                      .               Cost
                                                       fMay, 1973)

1. Primary Treatment                                   $130,000
2. Activated Sludge Treatment      ,                     500,COO
3. Aerated Lagoon                                       350,000
                                       TOTAL*          $980, 000"
includes 20% for engineering and
contingencies               '   .   •

                     OPERATING COST ESTIMATE
                          ALTERNATIVE C
      Primary Treatment, Activated Sludge, Aeration Lagoon

Item                  '              .                     Cost

1. Manpower                                            $233,000
2. Electricity                                           48,000
3. Steam
4. water
5. Chemicals              ,                               29,000
6. Maintenance                                           49,000
                             TOTAL COST/YR             $359,000
Summary:

          Costs:  Incremental costs of $299,000 over
                  Alternative B would be incurred, thus
                  producing a total cost of $843,000.
          Reduction Benefits:  A BOD reduction of 1.8 kg/kkg
                  (150 mg/1)  (overall reduction of 95£), and
                  a suspended solids reduction of 0 percent.
                  (overall reduction of 69 percent.)


Alternative  p-J:   Installation  of  Pre-Press  Evaporation   of
Process Water Discharge to Lagoon
                               248

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Summary:
This  alternative  is a new process separate from those discussed
previously.  Alternative D consists of the  addition  of  a  pre-
press  inplant  which  results in waste water discharges totaling
7.4 I/sec  (117 gal/min) being discharged from the  pre-press  and
the  hot  press.   The total waste flow would be passed through a
screen,  primary  clarifier,  and  evaporator.   The   evaporator
condensate is then discharged.
                    INVESTMENT COST ESTIMATE
                         ALTERNATIVE D-1
                  PRE-PRESS EVAPORATION, LAGOON

                                                      Cost
Item                                                (May  19? 3)
1.  Davenport Press with Auxiliaries                 $172,000
2.  Rotating Drum Screens installed                    8,000
3.  Clarif ier                                         26,0*00
4.  Liquor Holding Tank  (8 hours)                     30,000
5.  Quadruple Effect Evaporators with
    surface Condensers  (304 SS wetbed parts)          250,000
6.  Cooling Tower with Transfer Pumps  (2)             30,000
7.  Sludge Lagoon  (100 days)                          22,500
8.  Alum Storage and Metering System                  10,000
                      Subtotal                       $546,000
                      20% Engineering and
                      Contingencies                   109TOOQ
                          TOTAL                      $655,000

                     OPERATING COST ESTIMATE
                         ALTERNATIVE D-1
                  PRE-PRESS EVAPORATION, LAGOON

Item                                                   Cost

1.  Manpower                                        $175,000
2.  Electricity                                       8,000
3.  Steam                                             92,000
4.  Water                                             1,000
5.  Chemicals                                         18,000
6.  Product Worth  (deduct)                            89,000
7.  Maintenance                             	36,000
                         TOTAL COST/YR               241,000
          Costs;  Total cost of this  system would
                  be  $655,000.
          Reduction Benefits:  The  BODfi  of  this  system would
                  average  2.0 kg/kkg  production  (4.0  Ib/ton)
                  and the  suspended solids  would average 0.46 kg/kkg
                  production  (1.0 Ib/ton) for  an overall reduction
                  of  99.4  percent and 86 percent, respectively.
                               249

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   ACTIVATED SLUDGE TREATMENT OF CONDENSATE PRIOR TO DISCHARGE
                         ALTERNATIVE D-2
Approximately 90 percent of the contaminated condensate flow from
the  evaporators  is  treated biologically in an activated sludge
process.  The pH is first adjusted with  lime  and  polymers  are
added  to  assist  settling  in  the clarifier.  The treated flow
enters an aeration lagoon  of  approximately  one  day  retention
time.   The  flow  is transferred to the feed well of a clarifier
designed for 16,300 1/sq m/day (400 gal/sq ft/day)  The  overflow
from the clarifier is discharged to the environment.

The  underflow is pumped back to the inlet of the aeration lagoon
with part of this flow sent to a sludge  digester  and  on  to  a
holding lagoon.

                    INVESTMENT COST ESTIMATE
                         ALTERNATIVE D-2

       Activated Sludge Treatment Of Evaporator Condensate

Item                                                     Cost
                                                       (May, 1973)

1.  Neutralization System - Lime with Bucfcet
    Elevator, Lime Storage Tank Feeder, Shutoff
    Gate, Slurry Holding Tank with Agitator.  Slurry
    Pumps                                               $23,000

2.  Aeration Basin-621 cu m  (164,000 gal) with
    Aerator, Pumping Station                             39,400

3.  Clarifier - 1.7.6 m diam  (25 ft diam) - Steel with
    Feed Well Rake Mechanism and Drive, 3 sludge pumps
     (100 gal/min 3 50 ft TDH)                            36,000

4.  Waste Sludge Handling
    a.  Aerobic Digester Basin - 140 cu m
         (37,000 gal)
        3.6 m(12-ft) deep with liner - Aerator           37,400

    b.  Two ha  (five acre) lagoon with liner             15,000
        1.8 m  (6-ft) deep
                               Subtotal                 $150,800

                                20% Engineering and
                                Contingencies            30,200
                                TOTAL                   $181,bo5
OPERATING COST ESTIMATE
ALTERNATIVE D-2
ACTIVATED SLUDGE TREATMENT OF EVAPORATOR CONDENSATE

Item                                                Cost
                               250

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1.  Manpower                                        $233,000
2.  Electricity                                        5,000
3.  Steam                                              - -
4.  Water
5.  Chemicals                                         11,000
6.  Maintenance                                        8,000
                         TOTAL COST/YR             $257,000
Summary:
        Costs:  The add on cost for this
                system is $181,000.
        Reduction Benefits:  The BODS of this system would
                average 0.2 kg/kfcg production  (0.4  Ib/ton)
                and the suspended solids would average
                0.46 kg/kkg (0.9 Ib/ton) .
        SUMMARY OF TREATMENT EFFICIENCIES OF ALTERNATIVES

Flow  (cu m/day)    1,432    1,432     1,432    1,432     627       627
                      	Alternatives    	
Parameters            A     B-1      B-2     C       D-1       D-2

Raw BOD  mg/1      3,000    3,000     3,000    3,000   6,825     6,825
Eff. BOD  mg/1     2,700     300       600      150     450        45
Raw SS mg/1           800     800       800      800     200       200
Eff. SS mg/1          200     250       250      250     100       250
Raw BOD kg/kkg        33.8     33.8      33.8     33.8   33.8     33.8
Eff BOD kg/kkg        26.7      2.8       6.8      1.7    2.0      0.2
Raw SS kg/kkg          9.0      9.0       9.0      9.0    0.9      0.9
Eff. SS kg/kkg         2.1      2.5       2.5      2.5    0.5      1.3


            SUMMARY OF ALTERNATIVE  COSTS, AUGUST 1971

                  % BOD Investment   Yearly Operating  Total Yearly
Alternative   Removal  Cost	Cost	   Cost	$&
A
B-1
B-2
C
D-1
D-2
10
90
80
95
93.5
99.4
$109,000
544,000
413,000
843.000
566.000
722.000
$ 26,700
270,000
138T500
308,800
207,000
428,000
$36,500
319,000
175,000
385.000
258,000
493,000
                               251

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Factors Involved in the Installation of Alternative A

All existing wet process hardboard mills presently have screening
and  settling  or  the  equivalent of primary settling as part of
their treatment systems.  Several mills utilize a  single  lagoon
or  pond  for  both  settling  and  sludge storage.  The use of a
settling and storage pond in one unit is not desirable because of
anaerobic decomposition  which  resuspends  solids  and  releases
dissolved  organics  into  the  effluent.   The primary clarifier
recommended in Alternative A consists of a  mechanical  clarifier
with continuous sludge wasting to a sludge lagoon.

Mechanical clarifiers are one of the simplest and most dependable
waste  treatment  systems  available.   They are not sensitive to
shock loads and shutdown and start-up of manufacturing  processes
have  little  or  no  effect.   Primary  clarifiers and screening
devices are readily available on the market and an estimated time
of one year would be required for the design and construction  of
such  a  facility.  It is estimated that an area less than 0.6 ha
(1.5 ac)  would be  required  for  this  system.   The  additional
energy required to operate this system is estimated to be 22 kwh.
There  are no noise or radiation effects related to this process;
however, the disposal of 285  kg/day  of  solids  into  a  sludge
lagoon may be a source of odor problems.


Factors involved in the Installation of Alternative B

Alternative  B  consists  of an activated sludge system following
the facilities previously discussed in Alternative A.   Activated
sludge treatment of wet process hardboard mill waste can be quite
effective.    However,   the  system  has  all  of  the  problems
associated with  activated  sludge  treatment  of  domestic  plus
several  more.   These  include  the necessity for pH control and
nutrient addition.  Another major problem is that the sludge pro-
duced does not readily settle.  This can  frequently  cause  high
suspended  solids in the effluent.  Temperature apparently has an
effect not only in reducing the biological reaction rates  during
cold  weather,  but  also  in affecting the settling rates of the
mixed liquor suspended solids.


Activated  sludge  systems  require  constant   supervision   and
maintenance.   They  are  quite  sensitive  to shock loads and to
shut-down and start-up operations of the  manufacturing  process.
The equipment needed for activated sludge systems is available on
the  market;  however,  up  to  two  years  may  be required from
initiation of design until beginning  of  plant  operation.   The
energy  requirements  as  high as approximately 320 kilowatts are
needed to operate the process.  There is essentially no noise  or
radiation  effects  associated  with  the  process;  however, the
disposal of waste solids each day can cause odor problems.
                              252

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factors Involved in The Installation Of Alternative c

Alternative C consists of an aerated lagoon following the process
described in Alternative B.  Similar problems associated with the
operation of an activated sludge  process  hold  true  with  this
system.   Sludge  loadings  are  not a problem.  Temperature does
affect the system as it does any  biological  system..   The  only
additional  equipment  necessary  for  this  system  is  aeration
equipment of which an additional 225 Kw of  energy  is  required.
The  estimated  time of construction of this facility is one year
from initiation of design.  No noise or  radiation  problems  are
associated with this process, nor are there any odor problems.


Factors involved in the Installation of Alternative b

Alternative  D  is  a  completely  different  system  from  those
described in Alternatives A through C  and  may  involve  process
modifications.   This  system  consists  of the installation of a
pre-press inside the  wet  process  mill  to  dewater  the  stock
betwe'en the cyclone and the .stock chest.  This allows a projected
decrease  in  waste water flow from 1,432 cu m/day  (0.378 million
gal) to 629 cu m/day  (0.166 million gal).  Waste water  from  the
pre-press  and  the  wet  press  will  first be treated through a
screening and clarification system as described in Alternative A.
Next, instead of using a biological system to remove organics, an
evaporation system is used.  This system produces a saleable  by-
product   (being  produced  at  two  mills) .   A  portion  of  the
condensate is recycled back inplant  and  the  remaining  process
water  is  treated  in  an activated sludge" system similar to the
system described in Alternative B.


Evaporation systems must be fed at a relatively constant rate  as
they  are sensitive to shock loads.  Maintenance requirements are
high because of the nature of the material being evaporated.  The
evaporator must be cleaned out weekly, if  not  more  frequently.
Evaporation  equipment  can be obtained on the market; however, a
two year period from  initiation of design until start-up  is  not
unreasonable.   Noise and radiation effects are minor, but energy
requirements for steam  and  electricity  are  significant.   For
example,  approximately 150 kw are required to operate the system
in addition to steam requirements.   Air  pollution  factors  are
related  to  the  energy  requirement  as  fuel must be burned to
produce both steam and electricity.
WOOD PRESERVING-STEAM

Alternative Treatment and Control Technologies
                               253

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Cost figures which have been obtained for wood preserving  plants
vary  widely  for  a  number  of reasons.  In order to attempt to
provide a reasonable common basis for comparison, a  hypothetical
waste  treatment  facility  was  devised  to  meet  the suggested
standards and costs estimated  based  on  May  1973  construction
data.

The  treatments  to  be  provided  are;  A  - Oil separation; B -
Coagulation  and  filtration;  Biological  treatment  in  aerated
lagoons;   -  Biological  treatment  by  or activated sludge; D -
Chlorination  as  a  polishing  treatment.   The  two  biological
treatments  are  alternates,  and  either  one  or  the  other is
intended to be used.  For estimating purposes, a waste water flow
of 53,000 I/day (14,000 gal/day) was used.  The waste loading and
quality  of  effluent  which  is  expected  from  each  stage  of
treatment suggested is as follows;

 QUALITY OF EFFLUENT FROM EACH STAGE OF A WASTE TREATMENT SYSTEM
Parameter
  Raw

 Waste
           Treatments
             (mg/1)
            B        C
                     D
COD
40,000
7,260
3,630
410
300
Phenols            190

Oil 6 Grease     1,500
              190

              225
           190

            80
           2.5

            45
         0.5

          25
ENGINEERING ESTIMATES FOR A WOOD PRESERVING - STEAM PLANT

Alternative A:  Oil Separation

Standard  oil separation equipment, equipped for both surface and
bottom removal, can be used for this purpose.  Depending  on  the
treating  preservatives  used,  provisions  must be made for both
surface  and  bottom  removal  creosote  tends  to  settle  while
pentachlorophenol in oil will rise to the surface.
                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE A
                         Oil Separation
Item
1. Land including clearing
2, Oil separator, installed
                                          Cost

                                          $ 2,000
                                          18,000
                              254

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3.  Pumps, motors, starters, lighting                       1,200
4.  Pipe, valves, fittings                                  2,500
5.  Piping labor                                              600
6.  Electrical labor                                          500
          Subtotal                                       $24,800

Engineering contingencies                                  4,960
          TOTAL                                          $29,760

Summary:
     Capital cost                                        $29,760
     Annualized cost including operation and
          and maintenance                                $0.31/1000 1

Alternative B^  Coagulation and Filtration

The  coagulation  and  filtration  system  would  also  serve  to
equalize variations  in  rate  of  flow.   Several  possibilities
present themselves, but to economize on space a multi-compartment
tank  or  several  tanks,  rather  than  lagoons  were  selected.
Basically, the waste water  would  enter  a  tank  from  which  a
constant  flow  could  be  admitted  to  a rapid mix tank where a
proportioning   pump   would   add   the   coagulant    chemical.
Approximately  one half hour of rapid mixing would be followed by
one hour of slow mixing of the waste water/coagulant.  This would
be followed by about 6 hours of  sedimentation.   The  filtration
system  would  be slow sand filters with a total area of about 93
sq m  (1000 sq ft).


                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE B
                   Coagulation and Filtration

Item                                                      Cost

1.  Land including clearing                                $10,000
2.  Equalization tank                                        2,000
3.  Coagulation tank                                .        15,000
4.  Pumps, motors, starters, lighting                        1,500
5.  Sand filters                                             4,000
6.  Pipe, valves, fittings                                   2,000
7.  Piping labor                                             1,000
8.  Electrical labor                                           600
          Subtotal                                        $36,100

Engineering and contingencies                               7,220
          Total for B                                     $42,320

Summary:
     Capital cost                                         $42,320
     Annualized cost including operation

          and maintenance                                 $0.70/1000 1
                               255

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Alternative C-l^_  Biological Treatment, Aerated Lagoon

This treatment should result in a waste water  having  a  BOD  of
about  3000 mg/1 or about 375 Ib/day.  Assuming a normal aeration
efficiency, an aerated lagoon would require an input of about  15
hp  to  provide the necessary treatment.  The necessary detention
time would require a volume of 1.06 million 1  (280,000 gal).  For
about a 3 m depth (10 ft), 353 sq m  (less than 0.1 ac)  of surface
area will be required.  Two aerators of 7.5 hp each were selected
and are sufficient to provide the necessary aeration.
Item

1. Land including clearing
2. Liner, installed 3 $0.50 per sq ft
3. Two 7.5 hp aerators, installed
4. Pumps, motors, starters, lighting
5. Pipes, valves, fittings
6, Piping labor
7. Electrical labor
          Subtotal

Engineering and contingencies
          Total for C-l

Summary:
     Capital cost
     Annualized cost including operation
                  and maintenance

Alternative C-^i  Biological Treatment, Activated Sludge
 Cost

 $3,000
  3,000
  7,600
  1,500
.  1,200
    800
    500
$17,600

  3f520
$21,120
$21,120

$0.70/1000 1
The proposed activated sludge plant design is based on  the  same
influent  BOD  loading  of  about  3000 mg/1 or about 375 Ib/day.
Assuming 0.2 Ib BOD will produce one Ib of mixed liquor suspended
solids  (MLSS) and assuming a desirable concentration of 2500 mg/1
of MLSS, an aeration tank volume of 341,000  1  '{90,000  gal)  is
required.   Therefore a 378,000 I/day  (100,000 gal/day) activated
sludge package plant was selected.
                              256

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                    INVESTMENT COST ESTIMATE
                         ALTERNATIVE C-2
             Biological Treatment, Activated Sludge

Item                                               Cost
1.   Land, package plant and installation          $100,000
2.   Engineering and contingencies                   20,000
                              TOTAL COST          $120,000

Summary:

     Capital cost                                 $120,000
     Annualized cost including
       operation and maintenance                  $1.75/1000 1

Alternative D:  Polishing Treatment, Chlorination

The chlorination facility is intended to provide for  a  chlorine
dosage  of  up  to  500  mg/1.  For a design flow of 53,000 I/day
(14,000 gal/day) this will  require  up  to  27  kg   (60  Ib)  of
chlorine  per  day.   A  detention  time  of 3 to 6 hours will be
provided.  For ease of handling, 200 Ib cylinders were selected.

                    INVESTMENT COST ESTIMATE
                          ALTERNATIVE D
                     Polishing, Chlorination
Item                                                    Cost
1.  Chlorinator, installed                              $4,000

2.  Detention tank, installed                            1,000

3.  Automatic sampler, installed                         1,200

4.  Truck hand stand                                       800	
                             Subtotal                  $7,000

                     Engineering and contingen-
                             cies                       1,400

                        TOTAL COST                     $8,400

Summary:

     Capital cost                                      $8,400

     Annualized cost including
       operation and maintenance                    $0.64/1000 1

 Alternative E:.  Effluent Measurement

A recording flow measurement device was selected.

                    INVESTIMATE COS! ESTIMATE
                          ALTERNATIVE E
                               257

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                      Flow Recording Device

Item                                                 Cost
1.  Measuring element with recorder                  $2500
2.  Installation                                       500
                             Subtotal               $3,000

                     Engineering and contingen-
                             cies                      600

                             TOTAL COST             $3,600


Summary:

      Capital cost                                    $3,600

      Annualized cost including                      $0.16/1000 1
      operation and maintenance

Total capital costs for complete treatment
   with lagoons:                                       $106,200

Annualized cost for same system:                       $3.45/1000 1


WOOD PRESERVING

As discussed in Section III through VII, discharge of waste water
pollutants can be controlled by wood preserving  plants  in  this
sufacategory by implementation of in-process control technologies.
Therefore  there  are  no  costs  directly  related  to pollution
control.

Non-Water Quality Aspects

None of  the  waste  water  treatment  and  control  technologies
discussed   above   has   a   significant   effect  on  non-water
environmental quality.  The limited volume of sludge generated by
coagulation and biological treatments of waste water is currently
being disposed of in approved landfills by most plants.   Because
the  organic  components of these sludges are biodegradable, this
practice should present no threat to the environment.

WOOD PRESERVING - BOULTONIZING

The most common method of waste disposal in this  subcategory  is
evaporation.   Following oil separation the waste water is pumped
to a cooling tower for reuse as cooling water.   For  an  average
waste  flow  of  15,100 I/day  {4,000 gal/day), approximately one-
half of the water is evaporated during the  normal  operation  of
the  tower.  The excess water, about 7,600 I/day (2,000 gal/day),
is evaporated by raising the temperature  of  the  water  in  the
                               258

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tower  reservoir  using  a small heat exchanger.  Pan evaporation
may also be used.  However, since the volume  of  water  involved
and  the  heat  energy required for evaporation is about the same
for the two methods, the calculations which follow are  based  on
using a cooling tower.

The  cost of a cooling tower of a size needed at an average plant
is $24,000, including heat-exchanger and overhead fan to expedite
evaporation.  Because a tower would  be  required  regardless  of
pollution   control   activities,  the  total  investment  cannot
legitimately be charged to those activities.  Thus, in  computing
capital  investment  only  50 percent of the tower cost was used.
This percentage was selected because  the  tower  is  used  as  a
pollution-control  device to evaporate only one-half of the waste
water from a typical plant.  Tiie balance is  ^ost  regardless  of
pollution-control objectives.

Capital  investment  in  other  equipment directly concerned with
pollution-control is estimated to be $20,000.  All of this sum is
for oil separation, storage and transport of recovered  oil,  and
holding tanks and pumps for handling oil separator effluent.  The
total investment amounts to $32,000.

Operating  costs,  exclusive of energy requirroents, are estimated
to be $2,595/yr, or about $T,14/1000 1   ($4.32/1000  gal).   This
item is broken down as follows:

Item                    Cost

1.  Labor               $1800
2.  Repair Parts          795
                 TOTAL  $2595

Labor  cost  is based on 300 man-hr/yr and an hourly wage rate of
$6.00.

Energy is the most expensive item in disposing of  wastewater  by
evaporation.   Fuel cost to evaporate 7,600 I/day  (2,000 gal/day)
is estimated to be $14.54, for an annual cost  of  $4,361.   This
estimate  is  based  on  using  natural  gas  for fuel, a heat of
vaporization at 38°C(100°F) of 1739 kg cal/fcg  (1035' BTU/lb),  an
overall  heating  efficiency  of  65  percent,  and  gas  costing
$19.42/1000 cu m  ($.55 1000 cu m) .  Electric power to operate  an
overhead fan is estimated to cost $150 annually.

The  total  annual  cost  of  this  scheme  for waste disposal is
approximately $12,228 or about $5,38/1000 1  ($20.38/1000 gal)  of
excess  water  evaporated.   If  water  evaporated because Of the
normal operation of the cooling tower is included, the  per  unit
cost would be only one-half as great.
                               259

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                           SECTION IX

     BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE

The  effluent limitations which must be achieved by 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 timber products processing category, but rather
based upon performance levels achieved  by  exemplary  plants  or
best operating unit operations.

Consideration must also be given to;

          (a)  The total cost of application of technology
              in relation to the effluent reduction bene-
              fits to be achieved from such application;
          (b)  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)  Nonwater quality environmental impact,
              including energy requirements.

Best   Practicable   Control   Technology   Currently   Available
emphasizes treatment facilities at the  end  of  a  manufacturing
process  but 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
installation of the control facilities.
BARKING

Identification of Best Practicable
Control Technology Currently Available

Barking is an almost industry-wide pre-processing operation which
has been treated as a separate subcategory for the reasons  given
in  Sections  III and IV of this document.  The barking operation
consists  solely  of  removing  bark  by  pressure  or   abrasion
                               261

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Summary

Based upon the ipformation contained in Sections III through VIII
of this document and summarized above, a determination  has  been
made  that  the  degree  of effluent reduction attainable and the
maximum allowable discharge in the  Barking  subcategory  thorugh
the  application  of  the  best  practicable technology currently
available is no discharge of waste water pollutants to  navigable
waters.

A   variance  shall  be  allowed  for  those  barking  operations
utilizing  a  hydraulic  barker.   Based  upon  the   information
contained  in  Section  III  through  VIII  of  this document and
summarized above, a determination has been made that  the  degree
of  effluent  reduction  attainable  and  the  maximum  allowable
discharge in the Barking subcategory  for  hydraulic  barkers  in
preparation  for  veneer  or  plywood manufacture, is through the
application of the best practicable control technology  currently
available, as follows:

               30-day Average     Daily Maximum
               (Ib/cu ft)          (Ib/cu ft^
               kg/cu m            Jcg/cu m

BOD5                0.5              1.5
                    (0.03)             (0.09)
Total
Suspended           2.3              6.9
Solids              (0.14)             (0.43)
pH                 Within the range 6.0 to 9.0

VENEER

Identification  of  Best Practicable Control Technology' Currently
Available

The manufacture of veneer may or may not result in the generation
of process waste water, depending on the types  of  manufacturing
procedures   used.    The  unit  operations  required  in  veneer
manufacture have been discussed in detail  in  Section  III,  the
wastes  derived  from  each  of  the  operations characterized in
Section V, and treatment and control technology, when applicable,
detailed in Section VII.

An extensive technology exists which, when applied to each of the
unit operations in this subcategory, will result in no  discharge
of  waste  water  pollutants.  While the technology exists, it is
not, however, uniformly applied.

To meet this standard of" no discharge requires the implementation
of the following control technologies:

    1.  Substituting, for direct steam conditioning  of  logs,   (a)
    hot  water spray tunnels,  (b) indirect steaming or  (c) modified
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    steaming with the use of steam coils.   Hot water spray  tunnels
    where  water  is  heated  and  then  sprayed on the logs can be
    placed in existing steam vats with  only  minor  modifications,
    and  the  hot  water  collected  and  reused after settling and
    screening.   Modified  steaming  produces,  after   the   steam
    contacts  the  wood,  a condensate which may be revaporized and
    reused.  The small volume wood based sludge that  is  generated
    can be disposed or the procedures discussed in Section VII.

    2.   Discharge of contaminated waste water from hot water vats,
    where the water is heated indirectly, to a settling basin, with
    possible pH adjustment, and later reuse.

    3.   Manual removal of a portion of solid waste in  the  veneer
    dryer,  the  use  of  air  to blow out dust before using water,
    installation of water meters on water hoses  used  for  washing
    and  the  disposal  of  excess  veneer  dryer  washing water by
    irrigation, or containment and evaporation.  At least  one  9.3
    million  sq  m plant has reduced its water use for this purpose
    to 2,000 1/wk  (530 gal/wk).  By limiting  water  use  to  3,000
    1/wk, this water can be handled by containment or irrigation.

Rationale  for the Selection of Best Practicable Control Technolocry
Currently Available


             Age and Size of Equipment and Facilities

As  discussed  in  Section  IV,  the  age  and  size  of  a  veneer
manufacturing plant do not bear directly on the quantity or quality
of  the  waste water pollutants generated.  The age of a plant may,
however, be a factor in the  type  of  log  conditioning  procedure
used,  and  thus  in the selection of a variance and its associated
waste water control technology.


            Processes Employed and Engineering Aspects

All plants in this subcategory use essentially the same or  similar
production methods and equipment.  Sections III and VII treat these
process aspects in great detail.

Each  of  the  technologies  outlined above have been identified as
being in use in some portion  of  the  veneer  subcategory  of  the
timber  products  processing industry.  No plant, however, has been
found to utilize all of these control procedures.  About 100 of the
500 veneer and plywood plants have  retention  of  water  from  log
conditioning,  and  90  plants have control systems which eliminate
the discharge of dryer wash water.

                          Process Changes

Certain  peripheral  process  modifications  will   inevitably   be
necessary in the veneer manufacturing subcategory, in order to meet
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the no discharge regulation.  As indicated in the economic analysis
in  Section  VIII, a modification of log conditioning procedures is
more economically feasible than  the  addition  of  the  biological
-treatment units necessary to reduce BOD and solids loading from the
open steaming conditioning process.

Employing  the processes above, a softwood veneer plant supplying a
9.31 million sq m/yr plywood on a 0.53 mm basis production facility
that uses steam vats with direct steaming would have  a  continuous
effluent  of  about  1.9  I/ sec  (30 gal/min)  with a BOD loading of
about 410 kg/ day at 2500 mg/1 concentration and a suspended  solids
loading  of  325  kg/day  at  2000 mg/1 concentration.  Applying 85
percent BOD removal efficiency can reduce BOD to 61 kg/day, or  2.3
kg/1000 sq m of production, on a 9.53 mm
A  hardwood  veneer  plant  supplying  a  0.465  million sq m/yr (5
million sq ft/yr)  plywood production plant using  steam  vats  with
direct steaming would have a continuous effluent of about 0.5 I/sec
( 8   gal/mi n)   with  a  BOD  loading  of  30  kg/day  at  200  mg/1
concentration and a suspended solids loading  of  26  kg/day  at  a
concentration  of  700  mg/1.   Applying  85  percent  BOD  removal
efficiency can reduce BOD to 4.5 kg/day, or 3.4 kg/1000 cu m.

As discussed earlier, alternative procedures  for  conditioning  of
logs  exist  and indications are that the more practical procedures
would  be  the  selection  of  those  methods  that  eliminate  the
discharge of pollutants.

The  volumes  of  water required for cleaning of veneer dryers have
been determined to be  relatively  small.   Softwood  veneer  dryer
waste  water  is  in the range of 2600 I/day and hardwood about 530
I/day.  BOD5 waste loads are,  for  softwood  2.0  kg/day  and  for
hardwood 0.5 kg/day.  Softwood plant production base is 9.5 million
sq m/yr.  Hardwood plant production base is 0.46 million sq m/yr.

Because of the small volumes of water the relative ease of disposal
on  land,  and  the  impracticality  of  application  of biological
treatment to this waste water a  discharge  will  not  be  allowed,
except to an existing biological treatment system.  The small waste
loads  attributed  to  dryer  wash water will have no effect on the
operation and efficiency of the treatment  system.   The  pollutant
discharge  from  the  biological  treatment system serving a timber
products processing complex will not be increased to  allow  credit
for the veneer dryer cleaning input.


Nonwater Quality Impact and Energy Requirements

There  are  potentially  three  nonwater  related  pollutants:   (1)
emission of particulates from the veneer dryer,  (2) odors  released
from anaerobic containment ponds, and  (3) solid wastes.

There are currently no emission control systems installed on veneer
dryers.   There  is,  however, transferrable technology applicable.
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Particulates can be controlled utilizing inertial collectors of the
cyclone or mechanical type.  Volatile and condensable  hydrocarbons
can   be  controlled  by  condensation,  adsorption  or  scrubbing,
incineration, or  combinations  of  the  three.   As  air  emission
standards  become more stringent, control of particulate matter may
require the use of wet scrubbers, thus resulting in a  waste  water
relatively high in solids content.

The  bulk of the solid waste from veneer mills is comprised of wood
residues and bark.  These wastes are commonly used as fuel  in  the
boiler.   In addition to wood wastes are the settleable solids that
accumulate in ponds and  those  that  are  separated  in  screening
devices.   Disposal  of  the  small  amounts of this material which
result may be at the plant  site  or  the  waste  material  may  be
collected  by  the  local  municipality  with  eventual disposal by
landfill.  The proper disposal of these  wastes  will  ensure  that
they   present   no  significant  non-water  quality  environmental
problem.

In terms of energy requirements, a 9.3 million sq m/year veneer and
plywood plant will have a total energy demand  of  4500  kw  and  a
manufacturing  energy  cost  of  $180,000.   Additional  costs  for
implementation of the pollution control technology  discussed  here
and  in  section  VII range from $0 to $2300/yr.  These figures are
more closely examined in Section VIII.

Summary

Based upon the information contained in Sections III  through  VIII
of  this  document  and  summarized above, a determination has been
made that the degree  of  effluent  reduction  attainable  for  all
sources  in  the  veneer  manufacturing subcategory excluding those
which use direct steam conditioning as described below, through the
application of the Best Practicable  Control   Technology  Currently
Available  is  no  discharge  of  process waste water pollutants to
navigable waters.
A variance will be allowed for those  plants that both  (1)  as  part
of  their  existing  equipment  use   a log conditioning method rhat
injects steam directly into the conditioning vat, and  (2)  find  it
infeasible to implement the technology discussed above.

Based  upon  the information contained in Sections III through VIII
of this document and summarized above,  a  determination  has  been
made  that  the  degree  of  effluent reduction attainable for all
sources in the  Veneer  manufacturing subcategory  which  use  the
direct   steam   conditioning   as  described  above,  through  the
application of the Best Practicable   Control  Technology  Currently
Available is as follows:
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                            BOD
     Softwood
     Veneer:

     Hardwood
     Veneer:
      30-Day
      Average
      kg/cu m
      (Ib/cu ft)

       0.24
      (0.015)

       0.54
      (0.034)
 Daily
Maximum
kg/cu m
(Ib/cu ft)

 0.72
(0.045)

 1.62
(0.10)
6.0-9.0
6.0-9.0
PLYWOOD
Identification of the Best Practicable Control Technology Currently
Available

Plywood  may include several distinct process steps.  Alternatively
some of these may  take  place  in  the  veneer  manufacturing  and
processing  location.   These  steps are:  (1) drying, (2) clipping,
(3)  gluing, (4)  pressing, and (5)  trimming and packaging.

The unit operations required in  plywood  manufacturing  have  been
discussed  in detail in Section III, the waste derived from each of
the operations  characterized  in  Section  V,  and  treatment  and
control technology, as applicable, detailed in Section VII.

    Technologies  exist  which, when applied to the unit operations
in this subcategory, will result in  no  discharge  of  pollutants.
While  the technology exists, it is not uniformly applied.  To meet
this standard of no discharge  requires  the  implementation  of  a
portion or all of the following control technologies:

         1.   The use of steam to clean spreaders where  applicable
              and the use of high pressure water for cleaning;
         2.


         3.

         4.
The use of glue applicators that spray
rather than rollers;
                      the  glue  on
The use of glue washwater for glue makeup; and

Evaporation and spray application of  glue  water  on
bark going to the incinerator.
Rationale  for the Selection of Best Practicable Control Technology
Currently Available

                  Age and Size of Equipment and Facilities

As discussed  in  section  IV,  the  age  and  size  of  a  plywood
manufacturing  plant  do not bear directly on a quantity or quality
of the waste water pollutants generated.
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                Processes Employed and Engineering Aspects


All plants in this subcategory use essentially the same or  similar
production methods and equipment.  Sections III and VII treat these
process aspects in great detail.

    Each of the technologies outlined above have been identified as
being  in  use  in  some  portion of the plywood subcategory of the
timber products processing industry.  Yet no plant has  been  found
which  utilizes  all of these control procedures.  About 100 of the
500 veneer and plywood plants have  retention  of  water  from  log
conditioning,  and  aboul:  90  plants  have  control  systems which
eliminate the discharge of dryer wash water.

                          Process Changes


Certain  peripheral  process  modifications  will   inevitably   be
necessary  in  the  plywood  manufacturing subcategory, in order to
meet the no discharge regulation.  These are discussed in detail in
section VII and summarized, above.

          Nonwater Quality Impact and Energy Requirements

The bulk of the solid waste from plywood mills is comprised of wood
residues.  These wastes are commonly used as fuel  in  the  boiler.
In   addition  to  wood  wastes  are  ,the  settleable  solids  that
accumulate in ponds and  those  that  are  separated  in  screening
devices.  Disposal of this material may be at the plant site or the
waste  material  may  be  collected  by the local municipality with
eventual disposal by landfill.  The amount of solids generated from
these procedures is not expected to be great  and  proper  disposal
will  ensure  that  they  present  no  significant nonwater quality
environmental problem,

In terms of energy requirements, a 9.3 million sq m/yr  veneer  and
plywood  manufacturing  planti will  have  a total energy demand of
45,COO lew and a yearly energy^cost of $180,000.   Additional  costs
for  implementation  of  the pollution control technology discussed
here and in section VII range from $0 to $2300/yr.   These  figures
are more closely examined in Section VIII.

Summary

Based  upon , the information contained in Sections III through VIII
of this document and summarized above,  a  determination  has  been
made  that  the  degree  of  .effluent  reduction  attainable in the
Plywood manufacturing subcategory through the  application  of  the
Best  Practicable  Control  Technology  Currently  Available  is no
discharge of process waste water pollutants to navigable waters.
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HARDBOARD-DRY PROCESS
Identification of. Best Practicable
Control Technology Currently Available

The manufacture of hardboard using the dry process, as discussed in
Sections III and IV is accomplished through a series of  operations
that  for  the  purposes  of  developing  effluent  guidelines  and
standards  were  considered  on  a  unit  operation  basis.   Water
requirements, waste water generation and quality, and opportunities
for  reuse  and  disposal,  either  within the unit operation or in
other  operations  in  the  dry  process  hardboard   manufacturing
process,  were  determined  from  this  information.   Dry  process
hardboard manufacturing focuses on seven primary  unit  operations:
(1)  log  washing,   (2)  chipping,  <3) fiber preparation,  (4) dry-
felting, (5) pressing and tempering, (6)  humidification,  and  (7)
trimming and packaging.

It  has  been  demonstrated  that  technologies exist (discussed in
Section VII) which, when applied to each of  the  unit  operations,
will result in no discharge of pollutants.  To meet the standard of
no  discharge  requires the iimplementation of the following control
technologies:

    1.   Recycle of log wash and chip wash water  and  disposal  of
         the solids by landfill or use as boiler fuel.

    2.   Operation of the resin system as  a  closed  system,  with
         wash   water  being  recycled  as  make-up  in  the  resin
         solution.

    3.   Neutralization of caul water, and disposal by  impoundment
         or spray irrigation.

    4.   Elimination  of  discharge  from  humidification  by   the
         implementation  of  in-plant control, including reasonable
         operating and process management processes.

Rationale for the Selection of Best Practicable Control  Technology
Currently Available

            Processes Employed and Engineering Aspects

Log  washing in the dry process hardboard manufacturing subcategory
is practiced by about 15 percent of the mills.  The volume and  the
characteristics  of  the waste waters vary depending on harvesting,
transportation and storage practices and  conditions.   Wash  water
may  be  fresh, process, or cooling water and can be recycled after
settling.  Slowdown is required only infrequently and  one  of  the
two  plants currently washing logs is disposing of the small volume
of water by land irrigation.  Settled sludge may be disposed of  by
landfill.
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Water  used  in  the  formulation  of  binders for hardboard can be
incorporated in the hardboard and disposed of by evaporation in the
pressing operation.  Waste water is generated only during  cleaning
of  the  resin system, and the opportunity for use of the washwater
in makeup of resin solutions exists.  For these reasons  the  resin
system  can  be  operated  on  a closed system, and 6 out of 16 dry
process hardboard mills are currently achieving no  discharge  from
their resin systems.

Caul  washwater is a relatively small volume of water, amounting to
approximately 4 1/kkg of  production.   This  water  is  a  caustic
solution  used  to loosen the organic buildup on the cauls or press
plates.  It is replaced  periodically  when  the  concentration  of
dissolved  organics  builds up to a level that inhibits cleaning of
the plates.  Before disposal the washwater is  usually  neutralized
and the relatively small volume disposed of by impoundment or spray
irrigation.


There  are  no  waste  water losses in fiber preparation other than
evaporative losses, no waste water is generated in the forming  and
pressing  operations,  and  more  than  half of the mills report no
discharge of process water from the humidification operation.

                          Process Changes

There are no process changes necessary in order  to  eliminate  the
discharge  of waste water pollutants, but rather the implementation
of recycle and careful water management procedures.  Settling ponds
may be necessary in some instances as indicated.


The  primary  costs  and  changes  associated  with  achieving   no
discharge  of  waste water pollutants are related to the removal of
caul washwater as a pollutant.  Waste water  generation  from  this
operation  in normal operating practice is about 41/kkg  (1 gal/ton)
of production.  A system including volume retention of  one  week's
caul  washwater   (6,700  1)  and  transportation  costs  to  a land
disposal  site  would  cost  about   $25,000/yr.    Operation   and
maintenance costs for this system would be about $3,000/yr.

Nonwater Quality Impact and Energy Requirements

The single nonwater quality environmental impact from the treatment
and  control  technologies  presented is the problem of disposal of
minor volumes of sludges.  Proper disposal will ensure  that  solid
waste presents no significant non-water quality impact.

Energy  costs  are  limited to pumping and instrument operation and
are estimated to be less than $100/yr.  About  50  percent  of  the
plants  in  this  subcategory will be required to add treatment and
control systems to comply with this alternative.
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Summary

Based upon the information contained in Sections III  through  VIII
of  this  document  and  summarized above, a determination has been
made that the  degree  of  effluent  reduction  attainable  in  the
Hardboard-Dry   Process   manufacturing   subcategory  through  the
application of the Best Practicable  Control  Technology  Currently
Available  is  no  discharge  of  process waste water pollutants to
navigable waters.


No limit is established for fire control water.  This effluent will
be collected and should receive at least primary  screening  before
discharge.

HARDBOARP-WET PROCESS

Identification of Best Practicable Control Technology Currently Available

Wet  process hardboard is manufactured using seven distinct process
steps or unit operations:   (1) log washing,  (2) chipping,  (3) fiber
preparation,  (4)  wet-felting  (mat  formation),  (5)  drying  and
pressing,  (6) numidification, and (7) trimming and packaging.  Each
of  these  unit  operations has been discussed in detail in section
III, the  wastes  derived  and  characterized  in  Section  V,  and
treatment and control technologies detailed in"Section VII.

Technology is currently available and demonstrated which can reduce
the level of pollutants to zero in all of the unit operations, with
the  exception  of  those singular to the fiber preparation and mat
forming process.  Treatment and  control  schemes  are  in  use  in
individual  plants  within this subcategory, which reduce pollutant
discharge to the best practicable control technology limits as  set
forth herein.

To  meet  the  limitation  in  wet  process hardboard manufacturing
requires the implementation of the  recycle  and  water  management
policies  described  in Section VII and summarized in the following
paragraphs on the wet process hazdboard sutcategory.

The best practicable control technology currently  available  which
will   result   in   reduced   pollutant   loading   requires   the
implementation of all or part of the following:

    1.   Recycle of process water as dilution water, utilization of
         heat  exchangers  to  reduce  temperature,   and   gravity
         settling,  screening,  filtration,  or flotation to reduce
         suspended solids.

    2.   Treatment of total waste water flow  by  primary  settling
         combined  with  screening, and followed by aerated lagoons
         or activated sludge or both, with probable  pH  adjustment
         prior to biological treatment.
                               272

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    3.   Disposal of sludge by aerobic digestion in sludge lagoons,
         recycle inplant, or as land fill.

Rationale for the Seletion of Best Practicable  Control  Technology
Currently Available

            Processes Employed and Engineering Aspects

The   level  of  technology  summarized  above,  and  the  effluent
reductions suggested are  being  attained  by  22  percent  of  the
manufacturing  plants  in  this  subcategory.   Four  (U) mills are
reaching 60 to 90 percent efficiencies for suspended solids removal
through the use of filters and gravity separators.   One  mill  has
reduced its discharge, by inplant modifications without end of line
treatment,  to  2.3  cu  m/kkg  of production  (630 gal/ton) and BOD
discharge to 8.5 kg/kkg  (17 Ib/ton).  Two (2) plants are  known  to
use chemical treatment combined with sedimentation and flotation to
reduce  solids,  COD,  and  soluble  organics.   All of the ten wet
process plants have screening and primary  clarification/  3  mills
have  activated  sludge systems, 2 use activated sludge followed by
an aerated lagoon, and 2 plants evaporate process water and dispose
of the solids by land disposal or selling the  concentrated  solids
as cattle feed.

Information  obtained  from  5 wet process plants showed an average
waste water discharge of 9.0 cu m/kkg of production (2376 gal/ton).
Raw waste water characteristics were 27.8 kg/kkg  (61.1 Ib/ton) BOD,
and 8.4 kg/kkg  (18.5 Ibs/ton) suspended solids.

The treatment and control technologies summarized above are each in
use in at least one manufacturing plant in  this  subcategory,  and
each has a demonstrated high degree of engineering reliability.

                          Process Changes

There  are  no  significant  process  changes  required; rather the
addition of certain treatment capabilities  and  implementation  of
water  recycle  and  conservation  practices will be needed to meet
these limitations.
Non-Water Quality Impact and Energy Requirements

Sludge generated in the treatment systems must be disposed of,  and
as  land fill is one suggested means of disposal, there may be some
minor environmental impact.  Proper disposal techniques will ensure
that the non-water quality impact is minimal.

Energy costs  for  alternative  technologies  are:   screening  and
primary  settling,  $2,000/yr; activated sludge after screening and
clarification,  $28,000/yr;  aerated  lagoon  after  screening  and
clarification,  $21,000/yr;  and  aerated  lagoon  after screening,
clarification  and  activated  sludge,  $48,000/yr   (based  on   an
electricity cost of $0.01/kwh).
                              273

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Summary
Based upon the information contained in sections III through VIII
of this document, a determination has been made that the degree of
effluent reduction attainable and the maximum allowable discharge
in the wet process hardboard subcategory through the application of
the best practicable control technology currently available is as
set forth in the following table:
                                 30-Day          Daily
                                 Average         Maximum
                                 kg/kkg          kg/kkg
                                (Ib/ton)        (Ib/ton)
      BODS
      Total
      Suspended Solids
      pH
  2.6
 (5.2)
  5.5
(11.0)

  6.0-9.0
  7.8
(15.6)
 16.5
(33.0)

  6.0-9.0
WOOD PRESERVING

Identification of Best Practicable Control Technology Currently
Available

The manufacturing, process in this subcategory consists primarily of
indirect heat conditioning and preservative injection operations.
There are numerous differences in specific processes and types of
preservatives, but waste water characteristics, as detailed in
Section V, are similar and thus subject to the same treatment
methods.  Many of the pollutants superficially characteristic of
this subcategory are traceable to nonprocess wastes which shall be
discussed in future studies.  Sections VII and VIII detail specific
technology and the costs associated with the technologies.

The discharge of waste water pollutants may be eliminated through
the implementation of the following control technologies:

    1.   Elimination of equipment and piping leaks, and
         minimization of spills by the use of good housekeeping
         techniques:
    2.   Recovery and reuse of contaminated water, generated in
         processes employing salt-type preservatives and fire-
         retardant formulations, as make-up water for treating
         solutions;
    3.   Modification of existing nonpressure processing equipment
         in order to eliminate the introduction of water from
         precipitation in the treating tanks, and;
    4.   Segregation of contaminated and uncontaminated water
         streams.  The latter includes condensate from heating
         coils and heat exchangers, and noncontact cooling water.
                               274

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Rationale  for  Best  Practicable  Control   Technology   Currently
Available

                          Process Changes

No   significant  process  changes  are  necessary  to  meet  these
standards but control techniques  would  have  to  be  implemented.
This technology is based on the fact that there exist opportunities
to reuse the limited amount of waste water generated; the recycling
of  process  water  from  salt type treatment is practicable and is
being practiced in at least one  plant  in  the  subcategory;  and,
there is no process waste water generated in nonpressure processes.

Non-Water Quality Impact and Energy Requirements

The  suggested  technologies are based primarily on modification of
iriplant practices and controls, and as a result have little  impact
on  other  environmental considerations.  Limited amounts of sludge
would be generated from the suggested biological systems.   Sludge,
however,  is  readily  biodegradable  and  thus  presents  no great
environmental problem if disposed of properly.

The cost associated with achieving  the  effluent  limitations  are
minimal for this subcategory.

Oil  separation,  already in place at 95% of wood preserving plants
has a cost of $0.31/1000 1 for annualized cost including  operating
and  maintenance.   Evaporation  for 7,600 I/day for a hypothetical
plant may be expensive and is related to the cost of  natural  gas.
The total annual cost would be about $6.00/1000 1.

Summary

Based  upon  the information contained in Sections III through VIII
of this document, a determination has been made that the degree  of
effluent  reduction  attainable  in the Wood Preserving subcategory
through the application of the best practicable control  technology
currently   available  is  no  discharge  of  process  waste  water
pollutants to navigable waters.


WOOD PRESERVING - BOULTONIZING

Identif ication of Best  Practicable  Control  Technology  Currently
Available

Wood  conditioning  by  the  Boulton process involves five distinct
process steps: 1) placing  wood  to  be  treated  into  a  treating
cylinder,  2)   sealing  the  cylinder, 3) putting treating chemical
into the cylinder, 4) applying heat and pressure (by steam coils or
heat exchanger) and 5) drawing a vacuum to  remove  moisture.   The
extracted  water passes through a condenser and goes to a hot well.
The waste water volume is only that amount removed  from  the  wood
itself.
                               275

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The  best  practicable control technology currently available which
will result in no discharge of waste water pollutants includes:

    1.   The  elimination  of  equipment  and  piping  leaks,   and
         minimization  of  spills  by  the use of good housekeeping
         techniques, and;

    2.   Disposal of the small volumes of water  removed  from  the
         wood, by evaporation or percolation.

This  technology  is  currently utilized in at least 4 plants which
are now achieving no discharge of waste water pollutants.  Sections
VII and VIII detail specific technology and cost analyses.

Rational  For  Best  Practicable   Control   Technology   Currently
Available

The waste water generated by this manufacturing procedure is in the
range  of  100  1/cu m of wood treated.  This volume of waste water
can be disposed of by evaporation, possibly assisted  by  the  heat
available  from  auxiliary  operations.   The  volume or ability to
dispose of the waste water is not influenced by the age or size  of
the facility.

The  capital cost of achieving no discharge of pollutants from this
subcategory ranged between $5,500 and  $112,000  depending  on  the
practices  and  methods used at four different plants.  These costs
were obtained from plants that have installed the  technology  that
achieves no discharge,  technology.

Summary

Based  upon  the information contained in sections III through VIII
of this document and summarized above,  a  determination  has  been
made  that  the degree of effluent reduction attainable in the Wood
Preserving - Boultonizing subcategory through  the  application  of
the  best  practicable control technology currently available is no
discharge of process waste water pollutants to navigable waters.
WOOD PRESERVING - STEAM

Identification of Best
Available
Practicable  Control  Technology
Conditioning  and preservative injection are the primary sources of
waste water pollutant generation in this  subcategory.   Condensate
from  steaming  is  the most heavily contaminated since it comes in
contact with the preservative in the treating vessel; vacuum  cycle
water  following  steam  conditioning,  and  water  used  to  clean
equipment are also heavily  contaminated.   These  operations  have
been  discussed  in  detail  in  Section  III,  wastes  derived and
characterized in Section V, and treatment and control technologies,
when applicable, discussed in Section VII.
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To meet the standards set forth herein will require the use of  the
following inplant control and treatment technologies:

    1.   Installation of oil recovery equipment (oil separators) to
         reduce influent to biological systems  to  less  than  100
         mg/1;

    2.   Minimization of waste water volume by  the  implementation
         of rigorous inplant water conservation practices;

    3.   Elimination of equipment and plumbing leaks;

    4.   Segregation  of  contaminated  and  uncontaminated   waste
         streams, and;

    5.   Use of one or a combination of the following:   biological
         treatment    (tricking   filter,  activated  sludge),   soil
         irrigation,   oxidation   ponds,    chemical    oxidation,
         containment   and   spray  evaporation,  pan  evaporation,
         evaporation in cooling towers, and  incineration  of   high
         concentration oily waste waters.

Rational   for  the  Selection  of  the  Best  Practicable  Control
Technology Currently Available

             Age and Size of equipment and facilities

As discussed in Section VI, the age and size of the wood preserving
plants in this subcategory bear little relation to the quantity or
quality  of  the  process  waste  water  generated  and because the
treatment and control methods indicated as best practicable control
technology currently available are "end-of-the-line" processes.

            Processes Employed and Engineering Aspects

Inplant procedures which are currently in use in the industry,  and
which will minimize the volume of waste water that must be treated,
include  the  recirculation  of  direct-contact  cooling  water and
segregation of contaminated and uncontaminated waste streams.   All
of  the  methods  proposed  are standard in that they are used  by a
number of plants.  None present unique problems from an engineering
point of view.

Most wood preserving operations using oily based preservatives  have
oil-recovery systems.  Apart from environmental considerations,  it
is  economically  feasible  to  recover  and  reuse oil rather  than
discharge  it.   Chemical  methods   involving   flocculation   and
sedimentation  on  the oil separator effluent are most widely used,
generally  are  least  expensive,  and  are  effective  with    wood
preserving waste water.

Trickling  filter  treatment  efficiency  on a creosote plant waste
water has been shown to achieve 91 percent BOD removal, 77  percent
COD  removal  and  at  least  99 percent phenol removal.  Activated
                              277

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sludge has been demonstrated  to  reduce  COD  by  90  percent  and
phenols  by  99 percent.  Aerated lagoon systems can accomplish the
same efficiency, the main disadvantage being the necessity for more
extensive land area.

Land disposal  has  relatively  simple  operating  procedures,  low
capital  investment,  minimum  equipment  needs,  low operating and
maintenance costs, and good quality effluent in terms of color  and
oxygen  demand.  Its chief disadvantage is the land requirement (in
the range of 1 ha/3000 I/day).  BOD and phenol removal efficiencies
as high as 99.5 percent are reported.

Chlorine and ozone have been used successfully  to  remove  phenols
from  wood  preserving  waste  water.  Chlorine dioxide can also be
used.   Chlorination  will  reduce  COD  to  the  same  degree   as
flocculation  with  lime  and a polyelectrolyte.  carbon adsorption
will remove 96 percent of the phenols and 80  percent  of  the  COD
from a creosote waste water at an 8:1 dosage.

Effluent  from  the  oil  separation  system can be discharged to a
cooling tower.   Normal  evaporation  rates  for  a  cooling  tower
accounts  for  a loss of 7,500 I/day  (2000 gal/day).  Problems with
condenser efficiency are associated with the presence of oil in the
cooling water.

Non-Water Quality Aspects and Energy Requirements

None  of  the  waste  water  treatment  and  control   technologies
discussed above have a significant effect on nonwater environmental
quality.  The limited volume of sludge generated by coagulation and
biological treatments of waste water is currently being disposed of
in   approved  landfills  by  most  plants.   Because  the  organic
components of these sludges are biodegradable, proper disposal will
ensure  that  these  wastes  should  present  no  threat   to   the
environment,

Summary

Based  upon  the information contained in Sections III through VIII
of this document and summarized above,  a  determination  has  been
made  that  the degree of effluent reduction attainable in the Wood
Preserving-Steam subcategory through the application  of  the  best
practicable  control technology currently available is as set forth
in the following table;
                              278

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                             30-Day               Daily
                            Average              Maximum
                          kg/1000 cu m         kg/1000 cu m
                         (lb/1000 cu ft)      {1b/1000 cu ft)

COD                           550                  1100
                            (34.5)                (68.5)

Phenols                      0.65                  2.18
                            (0.04)                (0.13)

Oil and Grease              12.0                  24.0
                            (0.75)                (1.5)
pH                       6.0-9.0               6.0-9.0
                           279

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                             SECTION X

       THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE

INTRODUCTION

The effluen-t limitations which must be achieved by  July  1,  1983,
are  to specify the degree of effluent reduction attainable through
the application  of  the  best  available  technology  economically
achievable.   The best available technology economically achievable
is not based upon an average of  the  best  performance  within  an
industrial  category,  but  is  to be determined by identifying the
very best control and treatment technology employed by  a  specific
point  source  within  the  industrial  category or subcategory, or
transfer of technology from one industry  process  to  another.   A
specific  finding  must  be  made as to the availability of control
measures to eliminate the  discharge  of  pollutants,  taking  into
account the cost for such elimination.

Consideration must also be given to:

     (a)  the age of equipment and facilities involved;
     (b)  the process employed;
     (c)  the engineering aspects of the application
         of various types of control techniques;
     (d)  process changes;
     (e)  cost of achieving the effluent reduction
         resulting from application of the best
         available technology economically achievable, and
     (f)  nonwater quality environmental impact
          (including energy requirements).


In  contrast  to  the best practicable control technology currently
available, the best available  technology  economically  achievable
assesses  the availability in all cases of in-process modifications
and controls as well as control or additional treatment  techniques
employed at the end of a production process.

Those  plant  processes and control technologies which at the pilot
plant,  semi-works,  or  other  levelt   have   demonstrated   both
-technological  performances  and  economic  viability  at  a  level
sufficient to reasonably justify investing in such  facilities  may
be   considered   in   assessing   the  best  available  technology
economically   achievable.    The   best    available    technology
economically achievable is the highest degree of control technology
that   has  been  achieved or has been demonstrated to be capable of
being  designed for plant scale operation up  to  and  including  no
discharge  of  process  waste  water 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,  -the best available technology
economically achievable may be characterized by some technical risk
                              281

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with respect to performance and with respect to certainty of costs.
Therefore, the best available  technology  economically  achievable
may  necessitate some industrially sponsored development work prior
to its application.

BARKING

Identification  of  the  Best  Available  Technology   Economically
Achievable

As   summarized   in  Section  IX,  the  best  practicable  control
technology currently available  is  no  discharge  of  waste  water
pollutants  into  navigable  waters.  Therefore, the best available
technology economically achievable in the Barking subcategory is no
discharge of waste water pollutants to navigable waters.

This limitation can be achieved by:

    1.  Selection of a barking method that does not  have  a  waste
         water effluent;
    2.   Selection of a barking method that has  a  relatively  low
         volume  of  water use, and treating and reusing that water
         either within the  unit  operation  or  within  the  total
         manufacturing operation, or;
    3.   Application of treatment of hydraulic barker effluent  and
         recycle  of  that  water to the degree that eliminates the
         discharge of pollutants to navigable waters.

As noted in sections VII and IX  of  this  document,  treatment  of
hydraulic  barker  effluent is already in place in one plant and is
currently resulting  in  the  achievement  of  almost  100  percent
recycle of process water in that plant.

This recycle is being achieved by a treatment process that includes
screening,   coagulation,  clarification,  pH  control,  and  algae
control.

Effluent Reduction Attainable Through the Application of.  the  Best
Available Technology Economically Achievable

Based  upon the information contained in. Sections III through IX of
this document, and consistent with the discussion presented  above,
a   determination  has  been  made  that  the  effluent  limitation
representing the degree of effluent  reduction  attainable  in  the
Barking  subcategory  through the application of the best available
technology economically achievable is no discharge of process waste
water pollutants to navigable waters*  Application of  the  factors
listed in Section IX does not allow variation from the no discharge
limitation  set  forth in this section for any point source subject
to such effluent limitation.
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VENEER

Identification  of  the  Best  Available  Technology
Achievable
Economically
The  best  practicable  control  technology currently available, as
defined in Section IX, is no discharge of waste water pollutants.

The best available technology economically achievable in the Veneer
subcategory is:

    1.   The substitution, for direct steam  conditioning  of  logs
         (a)  hot water spray tunnels, (b) indirect steaming, or  (c)
         modified steaming with the use of steam coils;
    2.   Discharge of contaminated waste water from hot water  vats
         to settling ponds for reuse, and;
    3.   The use of dry veneer dryer  cleaning  methods  or  proper
         land  disposal  of the quantities of waste water generated
         from wet cleaning procedures.
Effluent Reduction Attainable Through the Application of
Available Technology Economically Achievable
   the  Best
Based  upon  the information contained in Sections III through VIII
of this document, and consistent with the discussion in Section  IX
a   determination   has  been  made  the  the  effluent  limitation
representing the degree of effluent  reduction  attainable  in  the
Veneer  manufacturing  subcategory  through  the application of the
best available technology economically achievable is  no  discharge
of process waste water pollutants to navigable waters.  Application
of the factors listed in Section IX does not require variation from
the  effluent  limitation  set  forth in this section for any point
source subject to such effluent limitation.

PLYWOOD

Identification of Best Available Technology Economically Achievable

As summarized in Section IX, best  practicable  control  technology
currently   available  is  no  discharge  of  process  waste  water
pollutants to navigable waters,  waters.  Therefore, best available
technology economically achievable is no discharge of  waste  water
pollutants  into navigable waters.  This limitation can be achieved
by:

    1.   Elimination of discharge from the gluing operation in  the
         plywood  subcategory  including reduction of the amount of
         fresh water used by  the  use  of  waste  water  for  glue
         formulation,  monitoring  of  glue  and  glue  waste water
         concentrations, the use of steam to clean spreaders  where
         applicable,  the  use  of high pressure water for cleaning
         operations, and the use of spray applicators for glue.
    2.   Dry housekeeping  procedures  and  judicious  use  of  wet
         cleaning water.
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Effluent  Reduction  Attainable Through the Application of the Best
Available Technology Economically Achievable

Based upon the information contained in Sections III  through  VIII
of  this document, and consistent with the discussion in Section IX
a  determination  has  been  made  that  the  effluent   limitation
representing  the  degree  of  effluent reduction attainable in the
Plywood manufacturing subcategory through the  application  of  the
best  available  technology economically achievable is no discharge
of process waste water pollutants to navigable waters.
HARDBOARD - DRY PROCESS

Identification  of  the  Best  Available  Technology
Achievable
Economically
As  summarized  in  Section  IX,  the  best  practicable technology
currently available in the  Hardboard  -  Dry  Process  subcategory
consists of:

    1.   Recycle of log wash and chip wash or disposal by landfill;
    2.   The operation of resin system as  a  closed  system,  with
         recycle  and  reuse  of resin wash water as make-up in the
         resin solution;
    3.   Neutralization  of  caul  wash  water  and   disposal   by
         impoundment or spray irrigation, and;
    U.   Elimination  of  discharge  from  humidification  by   the
         implementation of inplant control, including operating and
         process management procedures.

Effluent  Reduction  Attainable Through the Application of the Best
Available Technology Economically Achievable

Based upon the information contained in Sections III through IX  of
this  document, and consistent with the discussion in Section IX, a
determination  has  been  made   that   the   effluent   limitation
representing  the  degree  of  effluent reduction attainable in the
Hardboard - Dry Process subcategory through the application of  the
best  available  technology economically achievable is no discharge
of process waste water pollutants to navigable waters.
HARDBOARD - WET PROCESS

Identif ication  of  the  Best  Available  Technology
Achievable
Economically
The  best  available  technology  economically  achievable  in  the
Hardboard-Wet process subcategory includes:

    1.   Recycle of  process  water  as  dilution  water  utilizing
    temperature  control and suspended solids control to reduce the
    total plant discharge to 4.5 cu m/kkg  {1186 gal/ton), the  BOD5
    to  33.8  kg/kkg   (67.5  Ib/ton)  and the suspended solids to 9
    fcg/kkg  (18 Ib/ton);
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    2.    Installation of a pre-press and evaporation system;

    3.    Discharge of process water only from the pre-press and the
         wet press;

    4.    Treatment of the total  waste  water  flow  by  screening,
         primary settling, and evaporation;

    5*    Recycle of  a  portion  of  the  condensate  back  to  the
         process;

    6.    Activated sludge treatment of the excess condensate, and;

    7.    Sludge disposal by appropriate means*

            Processes Employed and Engineering Aspects


The press system has been used  on  semi-chemical  pulp  and  on  a
calcium bisulphite system.  Presses have been designed and operated
to  take  pulp from 10-15 percent up to 55 percent consistently (by
weight).  The filtrate removes a higher percentage of the dissolved
solids to treatment and results in a cleaner pulp going through the
stock system thus reducing the .rate of dissolved solids buildup  in
the  system.  Full scale trials run on a semi-chemical pulp mill in
Scandinavia showed a waste liquor  recovery  of  85  percent  on  a
weight basis.

The  discharge  water  from  the  press  is passed over a screen to
remove fiber clumps, which are returned to the process.  The screen
effluent is diverted to a clarifier feedwell where liquid  alum  is
added  to aid flocculation.  The clarifier is expected to remove 75
to 90 percent of  the  suspended  solids.   Waste  liquor  is  then
evaporated  to 65 percent solids and disposed of by incineration or
as a byproduct,  contaminated condensate from the  evaporators  may
be treated in an activated sludge system.

Screening  and  primary clarification  (for 10 percent BOD5 removal)
would cost $109,000 initial investment and $26,700 for added yearly
operating expenses.  All existing plants currently  have  screening
and  primary  clarification  in  place.  A prepress and evaporation
system would initially cost $566,000 with a yearly  operating  cost
of  $207,000  for  a  93.5  percent  BOD5  removal.  And a prepress
combined with evaporation and activated  sludge  treatment  of  the
condensate  would  accomplish  99.4  percent  BOD5  removal  for an
initial cost of $722,000 and yearly operating cost of $428,000.

Effluent Reduction Attainable Through the Application of  the  Best
Available Technology Economically Achievable

Based  upon  the information contained in sections III through VIII
of this document a determination has been made  that  the  effluent
limitation representing the degree of effluent reduction attainable
in the Hardboard-wet Process subcategory through the application of
                              285

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the  best available technology economically achievable is a maximum
discharge as follows:
    BODS,
    Total
    Suspended Solids
    PH

WOOD PRESERVING
          30-Day
         Average
         kg/kkg
        tlb/ton)

          0.9
       (1.8)
          1.1
       (2.2)

        6.0-9.0
  Daily
 Maximum^
 kg/kkg
(Ib/ton)

    2.7
 (5-4)
    3.3
 (6.6)

  6.0-9.0
Identification of the Best Available Technology Economically Achievable

As summarized in section IX and developed earlier in the  document,
the  best  available technology economically achievable in the Wood
Preserving subcategory includes:

    1.   Minimization of waste water volume by  the  implementation
         of rigorous inplant water conservation practices;
         segregation
         streams;
of  cont aminat ed  and  uncontaminated   water
    2.   Installation of oil recovery equipment to reduce  influent
         to treatment system;

    4.   Elimination of equipment and plumbing leaks, and;

    5.   Use of one or a combination of  the  following  biological
         treatment    (trickling  filter,  activated  sludge),  soil
         irrigation,   oxidation   ponds,    chemical    oxidation,
         containment   and   spray  evaporation,  pan  evaporation,
         evaporation in ccoling towers, and  incineration  of  high
         concentration oily waste waters.

Effluent  Reduction  Attainable Through the Application of the Best
Available Technology Economically Achievable

Based upon the information contained in Sections III through IX  of
this   document,  and  consistent  with  the  discussion  above,  a
determination  has  been  made   that   the   effluent   limitation
representing  the  degree  of  effluent reduction attainable in the
Wood Preserving sufccategory through the  application  of  the  best
available  technology  economically  achievable  is no discharge of
process waste water pollutants into navigable waters.
                               286

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WOOD PRESERVIKG-BOULTQNIZING

I denti f icati on  of  the  Bes-t  Available  Technology   Economically
Achievable


As summarized in section IX and developed earlier in this document,
the  best  available technology economically achievable in the Wood
Preserving-Boultonizing subcategory includes:

    1.  Minimization of waste water volume by the implementation of
         rigorous inplant water conservation practices;

    2.   segregation  of  contaminated  and  uncontaminated   water
         streams.

    3.   Installation of oil  recovery  equipment  to  improve  the
         quality of the influent to treatment system;

    4.   Elimination of equipment and plumbing leaks;

    5.   Use of one or a combination of the  following  treatments:
         soil  irrigation,  oxidation  ponds, containment and spray
         evaporation,  pan  evaporation,  evaporation  in   cooling
         towers.

Effluent  Reduction  Attainable Through the Application of the Best
Available Technology Economically Achievable

Based upon the information contained in Sections III through IX  of
this   document,  and  consistent  with  the  discussion  above,   a
determination  has  been  made   that   the   effluent   limitation
representing  the  degree  of  effluent reduction attainable in the
Wood Preserving-Boultonizing subcategory through the application of
the  best  available  technology  economically  achievable  is   no
discharge of process waste water pollutants to navigable waters.

WOOD PRESERVING-STEAM

Identification   of  the  Best  Available  Technology  Economically
Achievable


The low waste water flow rate that must be achieved to conform with
1983 requirements will necessitate a high  level  of  water  reuse,
changes  in  steaming  technique  among plants using open steaming,
efficient oil recovery systems, and the initiation of an  effective
preventive  maintenance  and  housekeeping  program.  The following
technologies related to  these  factors  have  been  considered  in
determining the best available technology economically achievable:

    1.   Minimization of the volume of discharge by   (a)  recycling
         all  direct  contact cooling water,  (b) reuse of a portion
         of the process water for cooling purposes,  (c)  insulation
                               287

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         of  retorts  and  steam  pipes  to  reduce  the  volume of
         cylinder  condensate,   (d)  use  of  closed  steaming   or
         modified-closed  steaming to reduce the volume of cylinder
         condensate  and  to  lessen  the  incidence  of  oil-water
         emulsion  formation,   (e)  reuse of all water contaminated
         with heayy  metals  in  preparing  treating  solutions  of
         salt-type  preservatives  and  fire  retardants,  and   (f)
         segregation  of  contaminated  and  uncontaminated   water
         streams;

    2.   Modification of oil-recovery systems  or  replacement,  as
         required, to insure efficient removal of oils; and

    3.   implementation  of   preventive   maintenance   and   good
         housekeeping  programs  to  reduce  spills  and  leaks and
         provide a standard procedure for cleaning  up  those  that
         occur.

Rationale  for  the  Selection  of  the  Best  Available Technology
Economically Achievable

            Processes Employed and Engineering Aspects

Some of the methods of reducing waste flow  are  standard  industry
practice,  and  would normally be adopted earlier than 1983.  These
include waste stream  segregation  and  recycling  of  contaminated
cooling water.

Closed  steaming  is applicable to virtually all plants using steam
conditioning.  It is the  single  most  important  inplant  process
change  that  a plant can make from the standpoint of both reducing
the volume of waste  water  that  must  be  disposed  of  and  also
reducing   emulsion  formation.   Modified-closed  steaming,  while
reducing the volume of waste water to a lesser extent  than  closed
steaming,  also  lessens  emulsion  formation.   In  addition, this
method substantially reduces steam requirements  by  retaining  the
hot steam condensate in the retort rather than discharging it as it
forms.

Like  closed  steaming,  insulation of treating cylinders and pipes
used in steam transfer potentially can reduce both  the  volume  of
condensate formed and the energy  requirements for steam generation.
The heat loss from an uninsulated metal vessel amounts to 7.3 kcal/
hr/sq  in  of  surface  area   (2.7  BTU/hr/sq ft) for each degree of
temperature difference  between  the  inside  and  outside  of  the
vessel.   For  an  uninsulated retort 2.13 m  (7 ft) in diameter and
36.57 m  (120 ft) long, the daily heat loss would  be  7.56  million
kcal   (30  million BTU) if the inside and ambient temperatures were
121°C and 27°c  (250°F and 80°F), respectively.  This  loss  can  be
cut  by  70  percent  by  proper  insulation.  As a result, , steam
requirements and,  the  volume  of  condensate  produced  would  be
reduced significantly.
                               288

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A  well executed preventive maintenance and housekeeping program is
an integral part of the treatment and control  technology  required
to   achieve  best  available  technology  economically  achievable
limitations.  Spills and leakages can largely  negate  the  efforts
directed   toward  other,  more  obvious  aspects  of  waste  water
management if they are  ignored.   The  areas  around  and  in  the
immediate  vicinity  of retorts and storage tanks are of particular
importance because of the opportunity for storm water contamination
from preservative drips and spills associated with  freshly  pulled
charges  and  loss  of  preservative  from plumbing and pump leaks-
Consideration should be given  to  paving  the  area  in  front  of
retorts  to  permit  channeling  of drips and spills to a sump from
which the oil can be recovered.

In addition to the  inplant  controls  described  above,  polishing
treatments may be required to achieve the best available technology
economically  achievable  limitations.  Treatments such as chemical
oxidation and carbon filtration have been used in treatment of wood
preserving waste waters or petroleum waste waters.  Chlorination of
pentachlorophenol waste water has reduced phenol content 95 to 10QS
at dosages up to 3.0 g/1 of CaOC12 as chlorine.  At a dosage  of  8
g/1  and  24  hour  contact time, 96% of phenols and 80% of COD was
removed from creosote waste water.   Dosages  over   8  g/1  showed
little  additional  improvement.   Similar results were obtained in
tests using pentachlorophenol waste water.

Effluent Reduction Attainable Through the Application of  the  Best
Available Technology Economically Achievable

Based  upon the information contained in Sections III through IX of
this  document,  and  consistent  with  the  discussion  above,   a
determination   has   been   made   that  the  effluent  limitation
representing the degree of effluent  reduction  attainable  in  the
Wood  Preserving-Steam  subcategory  through the application of the
best available technology  economically  achievable  is  a  maximum
discharge as follows;
                              289

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          COD


          Phenols


          Oil and Grease
  30-Day
  Average
 kg/1000 cu m
(lb/100 cu ft)

 110
  (6.9)

   0.064
  (0.003)

   3-4
  (0.2)
  Daily
 Maximum
 kg/1000 cu m
(lb/1000 cu ft)

220
 (13.7)

  0.21
  (0.014)

 6.8
 (0.4)
          PH
   6.0-9.0
 6.0-9.0
_
                                     290

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                            SECTION XI

             STANDARDS OF PERFORMANCE FOR NEW SOURCES
INTRODUCTION

This  level of effluent reduction is to be achieved by new sources.
The -term. "new source" is defined in the Act to  mean  "any  source,
the  construction  of  which  is commenced after the publication of
proposed regulations prescribing a standard  of  performance."  New
source technology shall be evaluated by adding to the consideration
underlying   the   identification   of  best  available  technology
economically achievable a determination of what  higher  levels  of
pollution  control  are  available thj:pugh the use of improved pro-
duction processes and/or treatment techniques.

In addition to considering the  best  in-plant  and  end-of-process
control   technology,   identified  in  best  available  technology
economically achievable, new source technology is to be based  upon
an analysis of how the level of effluent may be reduced by changing
the  production  process  itself.  Alternative processes, operating
methods or other alternatives must be considered.  However, the end
result of the analysis will be to identify effluent standards which
reflect levels of control achievable through the  use  of  improved
production  processes   (as well as control technology), rather than
prescribing a particular type of process or technology  which  must
be  employed.   A  further determination which must be made for new
source technology is whether a standard permitting no discharge  of
pollutants is practicable.

Specific Factors to be Taken Into Consideration

At least the following factors should be considered with respect to
production  processes  which  are  to  be analyzed in assessing new
source technology:

       a.  The type of process employed and process changes;

       b.  Operating methods;

       c.  Batch as opposed to continuous operations;

       d.  Use of alternative raw materials and mixes of raw materials;

       e.  Use of dry rather than wet processes  (including substitution
           of recoverable solvents for water) ; and

       f.  Recovery of pollutants as by-products.

BARKING

Effluent Reduction, Identification and Rationale for  Selection  of
New Source Performance Standards
                               291

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Based  on  the  information contained and developed in sections III
through IX of this document, a determination has been made that the
standard  of  performance  representing  the  degree  of   effluent
reduction  attainable  for  new sources in the Barking subcategory,
excluding hydraulic barking operations, through the application  of
the  best  practicable  demonstrated control technology, processes,
operating methods, or other alternatives is no discharge of process
waste water pollutants to navigable waters.

The standard of  performance  for  new  sources  is  based  on  the
following  production  raw  waste and waste water flow assumptions.
These assumptions are based on information presented in Section V:
    Production  (veneer or plywood)
    Effluent from the Barker
    BOD5 concentration
    Total Suspended solids  (TSS)
      concentration
          252 cu m/day
        6,540 cu m/day
          100 mg/1
         2000 mg/1
     The limitations are based on the following treatment
     efficiencies:

    Primary screening and settling   75% Removal SS

    Biological treatment
              BOD5 Removal

Available information indicated that variation in the effluent from
a biological treatment system processing  wastes  from  the  timber
products processing industry is 300 percent.

Based  upon  the information contained in sections III through VIII
of this document and summarized above,  a  determination   has  been
made  that  the  standard of performance representing the  degree of
effluent reduction attainable and the maximum  allowable   discharge
for  new  sources in the Barking subcategory that use the  hydraulic
barking process shall be as follows:
         BODS
         Total Suspended
           Solids
30-Day
Average
 kg/cu m
(Ib/cu ft)

  0.5
  (0.03)
   2.3
  (0.14)
 Daily
 Maximum
 kg/ cu m
(Ib/cu ft)

   1.5
  (0.09)
   6.9
  (0.43)
                               292

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VENEER
Effluent Reduction,, Identification, and Rationale for Selection
New Source Performance Standards
of
Limitations prescribed for new sources are applicable to all plants
in  the  veneer segment of the timber products processing industry.
No variation will be allowed for log conditioning by open steaming.
As discussed in section IX, alternative procedures to  conditioning
by open steaming exist and are in use in the industry currently.

Based  on  the  information contained and developed in Sections III
through VIII of this document, a determination has been  made  that
the  standard  of  performance  representing the degree of effluent
reduction attainable for new  sources  in  the  Veneer  subcategory
through  the application of the best available demonstrated control
technology, processes, operating methods, or other alternatives  is
no discharge of process waste water pollutants to navigable waters.

PLYWOOD

Effluent  Reduction. Identification. and Rationale for Selection of
New Source Performance Standards

As summarized in section IX, there currently exists  treatment  and
control technologies applicable and in practice in this subcategory
that are capable of eliminating the discharge of pollutants.


Based  on  the  information  contained and developed in Section III
through VIII of this document, a determination has been  made  that
the  standard  of  performance  representing the degree of effluent
reduction attainable for new sources in the  Plywood  manufacturing
subcategory   through   tiie   application  of  the  best  available
demonstrated control technology, processes, operating  methods,  or
other   alternatives   is  no  discharge  of  process  waste  water
pollutants to navigable waters.

HARDBOARD - DRY PROCESS

Effluent Reduction, Identification, and Rationale for Selection
of New Source performance Standards

As summarized in section IX, there currently  exist  treatment  and
control technologies applicable and in practice in this subcategory
that are capable of eliminating the discharge of pollutants.

Based  on  the  information contained and developed in Sections III
through IX of this document, a determination has been made that the
standard  of  performance  representing  the  degree  of   effluent
reduction   attainable   for   new  sources  in  the  Hardboard-Dry
subcategory  through  the  application  of   the   best   available
demonstrated  control  technology, processes, operating methods, or
                               293

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other  alternatives  is  no  discharge  of  process   waste   water
pollutants to navigable waters.

HARDBOARD ~^WET PROCESS

Effluent Reduction,. Identification, and Rationale for the Selection
of New Source Performance Standards

The waste loadings generated by the manufacture of hardboard by the
wet process come mainly from dissolved organics released during the
fiber  preparation  process.  Section VII discusses and sections IX
and X summarize technologies which will  result  in  a  significant
reduction of process waste water pollutants.


Based  on  the  information contained and developed in sections III
through VIII of this document, a determination has been  made  that
the  standard  of  performance  representing the degree of effluent
reduction  attainable  for  new  sources   in   the   Hardboard-wet
subcategory   through   the   application  of  the  best  available
demonstrated control technology, processes, operating  methods,  or
other alternatives is as defined below:
     BOD 5
     Total
     Suspended Solids
     pH Range

WOOD PRESERVING
 30-Day
 Average
 kg/kkg
 (]b/ton)

  0.9
 (1.8)
  1.1
 (2.2)

6.0 - 9.0
Daily
Maximum
kg/kkg
Ob/ton)

  2.7
  (5.4)
  3.3
  (6.6)

6.0 - 9.0
Effluent Reduction, Identification, and Rationale for the
Selection of New Source Performance Standards

As described in section IX, there currently exist treatment  and
control technologies applicable and in practice  in this  subcategory
that are capable of eliminating the discharge  of pollutants.

Based  on  the  information contained and developed  in Sections  III
through VIII of this document, a determination has been  made  that
the  standard  of  performance  representing the degree  of effluent
reduction attainable by the Wood Preserving subcategory  through  the
application of the best available demonstrated control   technology,
processes, operating methods, or other alternatives  is no discharge
of process waste water pollutants to navigable waters.
                               294

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WOOD PRESERVING-BOULTONIZING

Effluent Reduction, identification, and Rationale for the Selection
9.L New Source Performance Standards

As  described  in  section  IX, there currently exist treatment and
control technologies applicable and in practice in this subcategory
that are capable of eliminating the discharge of pollutants.

Based on the information contained and  developed  in  Section  III
through IX of this document, a determination has been made that the
standard   of  performance  representing  the  degree  of  effluent
reduction   attainable   by   the   Wood    Preserving-Boultonizing
subcategory   through   the   application  of  the  best  available
demonstrated control technology, processes, operating  methods,  or
other   alternatives   is  no  discharge  of  process  waste  water
pollutants to navigable waters.

WOOD PRESERVING-STEAM

Effluent Reduction, Identification, and Rationale for the
Selection of New Source Performance_Standards

The process by which wood is treated by plants in this  subcategory
is  direct and simple.  Basically, it consists of placing the stock
in a pressure retort, conditioning it using steam or vapors  of  an
organic  solvent,  and  impregnating it with a preservative or fire
retardant.  The opportunity for change in the production process of
an operation of this type is limited.   Alternative  raw  materials
are  not  available,  and the replacement of existing preservatives
with  new  or  different  chemicals  is  not  anticipated  in   the
foreseeable future.                                             ,

A   consideration   of  the  overall  operation  reveals  only  two
processing steps in which the opportunity exists for  changes  that
can  lead to reduced discharge.  Both are related to preparation of
stock: for preservative treatment,  and both are expensive  in  terms
of the capital investment required.  One of the methods is to treat
dry  stock,  and  thereby  abrogate the need to steam condition it.
The other method is to steam condition or  vapor  dry  stock  in  a
separate retort from the one in which the preservative treatment is
applied.   Both  methods, which are used to some extent by existing
plants, serve to separate  conditioning  operations  from  treating
operations   and   thereby  prevent  contamination  of  water  with
preservatives.
Approximately 30 percent of the plants in the U.S.
dry  a  portion  of  their stock prior to treatment.
percent  use  kiln  drying  for  all  their  stock.
investment  is  high  for this technology, amounting
kiln.  A minimum of 5 kilns would be required if all
treated  by  a  typical  three-retort  plant  were
preservative  treatment.   Total  investment  would
Including   $47,000   for  each  kiln  and  $13,000
currently  kiln
  Only about 10
  The   capital
 to $60,000 per
  the  material
dried  prior to
 be   $300,000,
 for  accessory
                              295

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equipment, gas and electric  service  and  the  laying  of  tracks.
Total operating costs for the system would be approximately $98,000
per  year.   Kiln  drying also darkens the surface of poles so that
some  poles  do'  not  meet  the  color  standards  under  which  an
increasing  percentage  of  the ones treated with pentachlorophenol
are sold.

A reduction in the volume of discharge can also be obtained by  air
seasoning stock before treating it.  Some air seasoning takes place
on  the yeard, in the normal processing of material and most plants
ordinarily maintain an inventory of untreated stock in open  stacks
to  expedite the filling of orders.  Any seasoning that occurs here
lessens  the  conditioning  time  required  when  the  material  is
treated. ,  To  air  season thoroughly, certain items, such as poles
and piling, take up to six months.  The  large  inventory  required
for  this  imposes  a  financial  burden  on  the owners and is not
practical during a prolonged period of high  demand.   Furthermore,
deterioration  is  a  problem in the South when stock is stored for
the time required for it to air season.

Steam conditioning or vapor  drying  in  a  separate  retort  would
require  three  additional  retorts  for  the  typical three retort
plant.  Capitol investment would be $150,000,  with  an  additional
cost  of  $110,000 for accessory equipment and installation.  Total
operating costs would be about $64,000/yr.

It is apparent from the  foregoing  discussion  that  there  is  no
simple,   economically  viable  method  to  reduce  the  volume  of
discharge from plants in this subcategory other than that based  on
the best available technology economically achievable.

Energy Requirements

Kiln  drying all stock would have a fuel cost of $72,000/yr for the
typical plant, based on a gas consumption of 99  cu  m/hr  for  312
days/yr operation.

Fuel  and  electricity  costs  for  a  separate  retort  system for
conditioning.would be $30,000 and $500, respectively.

Summary
Based on the information contained and developed  in  Sections  III
through VIII of this document and summarized above, a determination
has  been  made  that  the standard of performance representing the
degree of effluent reduction attainable for new sources in the wood
Preserving -Steam subcategory through the application of  the  best
available  demonstrated  control  technology,  processes, operating
methods, or other alternatives is as defined below:
                              296

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COD
Phenols
Oil and Grease
    30-Day
   Average
 kg/1000 cu m
(lb/1000 cu ft)

     110
      (6.9)

       0.064
      (0.003)

       3.4
      (0.21)
    Daily
   Maximum
 kg/1000 cu m.
(lb/1000 cu ft)

    220
      (13.7)

       0.21
      (0.014)

       6.8
      (0.4)
pH Range
      6.0-9.0
       6.0-9.0
                          297

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                            SECTION XII

                         ACKNOWLEDGEMENTS
The information presented in this document was developed
input and assistance of many persons and organizations.
with  the
The  data  base  and  current  state  of  pollution control in this
segment of the timber products processing  industry  was  developed
and  presented  by  Environmental  Science  and  Engineering, Inc.,
Gainesville, Florida, Richard H. Jones, vice president; and John D.
Crane, project manager, organized and directed the activity; Robert
A. Morrell and Leonard P. Levine served as project leaders for  the
veneer  and  plywood,  and  Jjarflboard  portions  of  the  industry,
Recognition is given to  the ••secretarial  staff  of  Environmental
Science  and  Engineering for their efforts in providing the Agency
with a draft report within  a  limited  time  schedule.   Dr.  John
Meiler  also  served  as  a consultant to Environmental Science and
Engineering for the hardboard industry.

The wood preserving portion of this document was developed  by  Dr.
Warren   s.    Thompson,   Director,  Forest  Products  Utilization
Laboratory, Mississippi State University.  Appreciation is extended
to him and his staff.

Industry associations and organizations that were involved  in  the
development  of  information and commenting included:  The National
Forest Products Association, The American Plywood Association,  The
Hardwood  Plywood  Assocation,  The American Hardboard Association.
The  American  Wood  Preservers  Association,  The  American   Wood
Preservers  Institute, The Society of American wood Preservers, The
southern  Pressure  Treaters  Association,  and  the  Quality  Wood
Preservers Society.

It is not possible to list the industry individuals who have worked
with  the  Agency  and  its  contractors  in the development of the
guidelines and standards  presented  in  this  document.   However,
their assistance and cooperation is appreciated.

The  Timber  Products  Processing  Working Group/steering committee
provided insight and constructive criticism of the support document
in its various stages of development.  The committee  was  composed
of  the following EPA personnel;  Ernst P. Hall, chairman. Effluent
Guidelines Division, Al Swing.,. Corvallis NERC,  G.  William  Frick,
Office of Enforcement and General Counsel, Arthur Mallon, Office of
Research and Development, Robert MCManus, Office of Enforcement and
General  Counsel,  D. Robert Quartel, Effluent Guidelines Division,
Willard Smith and Irving Susel,  Office  of  Economic  Development,
Reinhold  Thieme,  Office  of  Enforcement and General Counsel, and
Kirk Willard, Corvallis NERC.

Special thanks are expressed to  Ernst  Hall,  Effluent  Guidelines
Division  for   his  guidance and support.  Rob Quartel formerly of
                               299

-------
the Effluent Guidelines Division, served as project officer  during
the formative stages of this document.

Special  appreciation  is  extended  to  the  women of the Effluent
Guidelines Division who maintained their composure and charm during
the long and arduous task of typing,  retyping  and  revising  this
document during its development.  Thank you, in particular to Linda
Rose, Chris Miller, Darlene Miller and Fran Hansborough.
                              300

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                           SECTION XIII

                            REFERENCES

1.   Thompson, W. S., "status of Pollution Control in the Wood Preserving
    (in press).

2.   American Wood Preservers1 Association* Proceedings, vol. 68, pg. 275,
    286, 287, 1972.

3»   Forest Products Industry Directory, Miller Freeman Publications,
    San Francisco, 1972.

4.   Market profile - Softwood and Hardwood Plywood, U.S.A. and Canada,
    Forest industries, Portland, Oregon, 1969.

5.   Panshin, Alexis John et al* Forest Products;	Their Sources, Produc-
    tion, and Utilization, McGraw-Hill, New York, First Edition, 1950.

6-   Market Profile - Hardboard, Forest Industries, Portland, Oregon.

7.   MacDonald, Ronald G., Editor, and Franklin, John N., Technical
    Editor, The pulping of wood, second Edition, Volume I, McGraw-Hill,
    New York, 1969.

8.   Gehmr Harry, Industrial Waste Study of the Paper and Allied Products
    Industries, Environmental Protection Agency, July,  1971.

9.   "Plywood and Other wood-Based Panels," Food and Agricultural
    Organization of the United Nations, Rome, 1966.

10.  Bodien, Danforth G-, Plywood.Plant Glue Wastes Disposal, Federal
    Water Pollution Control Administration, Northwest Region, Pacific
    Northwest Water Laboratory, U. S. Department of,the Interior,
    1969,

11.  "FIberboard and Particle Board," Food and Agricultural Organization
    of the united Nations, Rome, 1958.

12.  Asplund, A., The Origin and Development of the Defibrator Process,
    FAO/ECE/Eoard Cons., Paper 5.2.

13.  Watts, E. W., Industrial Experience in the Manufacture of Smoc-th-
    2-sides Cardboard, FAQ/ECE/Board Cons., Paper 5.11.

14.  Gettle, Karl, A Guide for the study of the Manufacturing of
     Hardboard, American Hardboard Association and American Indus-
     trial Arts Association.

15.  Basic Hardboard - Proposed voluntary Product Standard TS 168a,
     American Hardboard Association, Revision of CS 251-63 Hardboard,
     February 13, 1973.
                              301

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16.  Statistical Policy Division of the Office of Management and
     Budget, U.S. Government Printing Office, Washington, D. C.,
     1972.

17.  Stephenson, J. Newell, Editor, Preparation and Treatment of
     Wood Pulp, Vol. 1, McGraw-Hill, New York, 1950.

18.  Schaumburg, Frank D., The Influence of Log Handling on Water
     Quality, Office of Research and Monitoring, U. S. Environmental
     Protection Agency, Washington, D.C., 1973.

19.  Haskell, Henry H., "Handling Phenolic Resin Adhesive Wash Water
     in Southern Pine Plywood Plants," Forest Products Journal, Vol.
     21, No. 9, September, 1971.

20.  Mortenson, A. W., Private Communications (Inferno Steam Systemss
     Portland, Oregon) April - June, 1973.

21.  Gran, Gunnar, Wastewater from Fiberboard Mills, Stockholm, Sweden,

22.  Leker, James E., Masonite Corporation, Private Communications,
     January - June, 1973.

23.  Thompson, W. S. and Dust, J. V., "Pollution Control in the Wood
     Preserving Industry.  Part 1. Nature and Scope of the Problem,"
     Forest Products Journal, 21(9), pp 70-75, 1971.

24.  Mississippi Forest Products Laboratory, Unpublished Data,
     Mississippi State University, State College, Mississippi,
     1970.

25.  Dust, J. V., and Thompson, W. S., "Pollution Control in the
     Wood Preserving Industry, Part 4.  Biological Methods of Treat-
     ing Wastewater." Forest Products Journal, in press, 1973.

26.  Sohlman, L., "Measures Taken by the Wallboard Mill of Skinn-
     skatteberg to Control Water Pollution," International Congress
     on Industrial Wastewater, Stockholm, Sweden.

     Effect of Inlet Conditions on Oil-Water Separators at SOHIO's
     Conference, pp. 618-625, 1965.

27.  Nepper, M., "Biological Treatment of Strong Industrial Waste
     from a Fiberboard Factory," Purdue Waste Water Conference,
     1967.

28.  Buckley, D. B. and McKeown, J. J., An Analysis of the Per-
     formance of Activated Sludge and Aerated Stabilization Basin
     Systems in Controlling the Release of Suspended Solids jn.
     Treated Mill Effluents to Receiving Waters, National Council
     of the Paper Industry for Air and Stream Improvement, Inc.,
     1973.

29.  Thompson, W. S., "Contribution of the Wood Preserving Industry
                               302

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     to Water Pollution," Proceedings, Conference on Pollution
     Abatement and Control In the Wood Preserving Industry, Missis-
     sippi Forest Products Laboratory, Mississippi State University
     State College, Mississippi 1971, pp. 50-75.

30.  American Petroleum Institute, Manual on Disposal of Refinery
     Wastes, Vol. I. Waste Water Containing Oil (6th Edition),
     92 pp, 1959.

31.  Thompson, W. S., Pollution Control, Chapter 11, D. D. Nicholas
     and W. E. Loos, Editors, Syracuse University Press, In Press,
     1973.

32.  Anonymous, Th_e Cost of Clean Waste:  Vol. Ill,  Industrial
     Waste Profiles, No. 5 - Petroleum Refining, U. S. Department
     of the Interior, Washington, D, C. 1967.

33.  Wallace, A. T., Rohlich, G. A., and Villemonte, J. R., "The
     Effect of Inlet Conditions on Oil-Water Separators at SOHIO's
     Toledo Refinery," Proceedings, 20th Purdue Industrial Waste
     Conference, pp. 618-625, 1965.

34.  Thompson, W. S.s "Pollution Abatement by Inplant Process Changes
     and Sanitation," Proceedings, Conference on Pollution Abatement
     and Control in the Wood Preserving Industry, Mississippi Forest
     Products Laboratory, Mississippi State University, State College,
     Mississippi, pp. 116-129, 1971.

35.  Jones, R. H., and Frank, W. R., "Wastewater Treatment Methods
     in the Wood Preserving Industry," Proceedings, Conference on
     Pollution Abatement and Control jn_ the Wood Preserving Industry.
     W. S. Thompson, Editor, Mississippi Forest Products Laboratory,
     Mississippi State University, State College, Mississippi, 1971,
     pp. 206-216.

36.  Simonsen, R. N., "Oil Removal by Air Flotation at SOHIO Refineries
     Proceedings, American Petroleum Institute 42CIII).
     pp. 399-406, 1962.

37.  Weston, R. F. and Merman, R. G., "The Chemical Flocculation
     of a Refinery Waste," Proceedings, American Petroleum Insti-
     tute, 34(111), pp 207-224, 1954.

38.  Middlebrook, £. J., "Wastes from the Preservation of Wood,"
     Journal, Sanitary Engineering Division, ASCE, 94, pp 41-56,
     1968.

39.  Gaskin, P. C., "A Wastewater Treating Plant for the Wood
     Preserving Industry," Proceedings, Conference on Pollution
     Abatement and Control in the Wood Preserving Industry, (W.. S,
     Thompson, Editor) Mississippi Forest Products Laboratory,
     Mississippi State University, State College, Mississippi, pp
     271-281, 1971.
                               303

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40.  Van Frank, A. J. and Eck, J. C.» "Water Pollution Control in
     the Wood Preservation Industry," Proceedings, American Wood
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41.  American Wood Preservers' Association, Report on Information
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     1956.

42.  Halff, A. H., "Slow Sand Filtration of Wood Treating Plant
     55, pp 184-188, 1959.

43.,  Halladay, W. B. and Crosby, R. H.s "Current Techniques of Treat-
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44.  Dust, J. V., "Sludge Production and Dewatering," Proceedings
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45.  Schwoyer, W., "The Permutit DCG Unit," Proceedings, Conference
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     dustry (W. S. Thompson, Editor), Mississippi Forest Products
     Laboratory, Mississippi State University, pp 96-115, 1971.

46.  Jones, R. H., "Toxicity in Biological Waste Treatment Processes,"
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47.  Dodge, B. F., and Reams, D. C., Jr., "Disposing of Plating
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48.  American Wood Preservers' Association, Report on Information
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49.  Bliss, H., "Developing a Waste Disposal Process," Chem. Eng.
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50.  Chamberlin, N. S., and Day, R. V., "Technology of Chrome Re-
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51.  Nyquist, 0. W. and Carroll, H. R., "Design and Treatment of
     Metal Processing Wastewaters," Sew. Indus. Wastes, 31, pp 941-
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52.  Stone, E.H.F., "Treatment of Non-Ferrous Metal Process
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                              304

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     Industrial Waste Conference, Purdue University, pp 848-855,
     1967.

53.  Hansen, N.H., and Zabban, W., "Des.ign and Operation Problems
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     249, 1959.

54.  Anderson, J. S. and lobst, E. H.s Jr., "Case History of Waste
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55.  Zabban, W. and Jewett, H. W., "The Treatment of Fluoride Waste"
     Proceedings, 22nd Purdue Industrial Waste Conference, p. 706-
     716, 1967.

56.  Gulp, R. L. and Stoltenburg, H. A., "Fluoride Reduction at La
     Crosse, Kansas," Jour. AWWA, 50, pp 423-437, 1958.

57.  Wamsley, R. and Jones, W. F., "Fluoride Removal," Water and
     Sewage Works, 94, pp 372-376, 1947.

58.  Magnusen, L. M., Waugh, T. C., Galle, 0. K., and Bredfeldt, J.,
     "Arsenic in Detergents, Possible Danger and Pollution Hazard,"
     Science, 168, pp 398-390, 1970.

59.  Shen, Y. S. and Chen, C. S., "Relation Between Black-Foot
     Disease and the Pollution of Drinking Water by Arsenic in
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     pp 173-190, 1964.

60.  Irukayama, K., Discussion of Paper "Relation Between Black-
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61.  Cherkinski, S. N. and Genzburg, F. I., "Purification of Arsen-
     ious Wastewaters," Water Pollution Abstracts, 14, pp 315-316,
     1941.

62.  Russell, L. V., "Heavy Metals Removal from Wood Preserving
     Wastewater," Proceedings, 27th Purdue Industrial Waste Con-
     ference, 1972, in press.

63.  Russell, L. V, "Treatment of CCA-, FCAP-, and FR-type Wastewaters,"
     Proceedings, Conference on Pollution Abatement and Control in the
     Wood Preserving Industry, (W. S. Thompson, Ed.) Mississippi Forest
     Products Laboratory, Mississippi State University, State College,
     Mississippi, pp 249-260, 1971.

64.  Barth, E. F., Salotto, B.V.S English, J. N., and Ettinger, M. B.,
     "Effects of a Mixture of Heavy Metals on Sewage Treatment Pro-
     cesses," Proceedings, 18th Industrial Waste Conference, Purdue
     University, pp 616-635, 1964.
                               305

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65.  Kugelman, I. 0., and McCarty, P. L., "Cation Toxicity and
     Stimulation in Anaerobic Waste Treatment," Journal t WPCF, 37(1):
     97-116, 1965.

66.  McDermott, 6. N., Barth, E. F.» Salotto, B. V., and Ettinger,
     M. B., "Zinc in Relation to Activated Sludge and Anaerobic
     Digestion Process," Proceedings . 17th Industrial Waste Conference,
     Purdue University, pp 461-4757 1964.

67.  Young, "Anionic and Cationic Exchange for Recovery and Puri-
     fication of Chrome from Plating Process Wastewaters," Pro-
     ceedings, 18th Industrial Waste Conference. Purdue University,
     pp 454-4$4, 1964.

68.  Gilbert, L., Morrison, W. S., and Kahler, F. H., "Use of Ion
     Exchange Resins in Purification of Chromic Acid Solutions,"
     Proceedings, Amer. Electroplating Soc., 39, pp 31-54, 1952.

69.  Costa, R. L.» "Regeneration of Chromic Add Solutions by Ion
     Exchange," Ind. Eng. Chem., 42, pp 308-311, 1950.

70.  American Wood Preservers' Association, Report on Information
     and Technical Development Committees, Proceedings, American
     Wood Preservers' Association, Washington, D. C., 53, pp 215-
     220, 1957.

71.  Sweets, W. H., Hamdy, M. K. , and Weiser, H. H., "Microbiological
     Studies on the Treatment of Petroleum Refinery Phenolic Wastes,,"
     Sewage Ind. Wastes, 26, pp 862-868, 1954.

72.  Reid, G. W. and Libby, R. W. , "Phenolic Waste Treatment Studies,"
     Proceedings, 12th Industrial Waste Conference, Purdue University,
     pp 250-258, 1957;:

73.  Ross, W. K. , and Sheppard, A. A., "Biological Oxidation of
     Petroleum Phenolic Wastewater," Proceedings, 10th Industrial Waste
     Conference, Purdue University, pp 106-119,
74.  Reid, G.  W. , Wortman, R. and Walker, R., "Removal of Phenol with
     Biological Slimes," Proceedings, llth Industrial Waste Conference,
     Purdue University, pp 354-357, 1956.

75.  Harlow, H. W., Shannon, E. S., and Sercu, C. L., "A Petro-Chemical
     Waste Treatment System," Proceedings, 16th Industrial Waste Con-
     ference,  Purdue University, pp 156-166, 1961.

76.  Montes, G. E., Allen, D. L., and Showell, E. B., "Petrochemical
     Waste Treatment Problems," Sewage Ind. Wastes, 28, pp 507-512,
     1956.

77.  Dickerson, B. W. and Laffey, W. T., "Pilot Plant Studies of
     Phenolic  Wastes from Petrochemical Operations," Proceedings,
     13th Industrial Waste Conference^ Purdue University, pp 780-799,
     1958.
                              306

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78.  Davies, R. W., Biehl, J. A., and Smith, R. M.t "Pollution Control
     and Waste Treatment at an Inland Refinery," Proceedings, 21st
     Industrial Waste Conference, Purdue University, pp 126-138, 1967.

79.  Austin, R. H., Meehan, W. G., and Stockham, J. D., "Biological
     Oxidation of Oil-Containing Wastewaters," Ind. Eng. Chem.,
     46, pp 316-318, 1954.

80.  Prather, B. V., and Gaudy, A. F., Jr., "Combined Chemical, Physical,
     and Biological Processes in Refinery Wastewater Purification,11
     Proceedings, American Petroleum Institute, 44(111), pp 105-112, 1964,

81.  Davies, J. J., "Economic Considerations of Oxidation Towers,"
     Proceedings, Conference on Pollution Abatement and Control
     in the Wood Preserving  Industry, (W. S. Thompson, Editor)
     Mississippi Forest Products Laboratory, Mississippi State
     University, State College, Mississippi, pp 195-205, 1971.

82.  Ullrich, A. H., and Smith M. W., "The Biosorpiton Process of
     Sewage and Waste Treatment," Sewage and Ind. Wastes, 23,
     pp 1248-1253,  1951.

83.  Ullrich, A. H., and Smith, M. W., "Operation Experience with
     Activated Sludge Biosorption at Austin, Texas," Sewage and
     Industrial Wastes, 29 pp 400-413, 1957.

84.  Besselieure, E. B., The Treatment of Industrial Wastes, McGraw-
     Hill, New York, 1969.

85.  Preussner, R. D., and Mancini, J., "Extended Aeration Activated
     Sludge Treatment of Petrochemical Waste at the Houston Plant
     of Petro-Tex Chemical Corporation," Proceedings, 21st Industrial
     Waste Conference, Purdue University, pp, 591-599, 1967.

86.  Coe, R. H., "Bench-Scale Method for Treating Waste by Activated
     Sludge," Petroleum Processing, 7, pp 1128-1132, 1952.

87.  Ludberg, J. E., and Nicks, G. D., "Phenols and Thiocyanate
     Removed from Coke Plant Effluent,11 Ind. Wastes (November) pp 10-
     13, 1969.

88.  American Wood Preservers' Association, Report of Wastewater
     Disposal Committee, Proceedings, American Wood Preservers'
     Association, Washington, D. C., 56, pp 201-204, 1960.

89.  Cooke, R., and Graham, P. W., "The Biological Purification
     of the Effluent from a Lurgi Plant Gasifying Bituminous Coal,"
     Int. Jour. Air Water Pollution, 9(3), pg. 97, 1965.

90.  Badger, E.H.M. and Jackman, M. I., "Loading Efficiencies in the
     Biological Oxidation of Spent Gas Liquor,11 Journal and Proceedings,
     Inst. Sewage Purification, 2:159, 1961.
                                 307

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91.  Nakashio, M., "Phenolic Waste Treatment by an Activated-Sludge
     Process," Hakko Kogaku Zasshi 47:389, Chem. Abs_. 71(8):236, 1969.

92.  Reid, 6. W., and Janson, R. J., "Pilot Plant Studies on Phenolic
     Wastes at Tinker Air Force Base," Proceedings, 10th Purdue
     Industrial Waste Conference, p 28, 1955.

93.  Kostenbader, P. 0. and Flacksteiner, J. W. (Bethlehem Steel
     Corporation), "Biological Oxidation of Coke Plant Weak Ammonia
     Liquor," J. WPCF, 41(2):199, 1969.

94.  Kirsh, E. J. and Etzel, J. E., "Microbial Decomposition of
     Pentachlorophenol," (Submitted for Publication, J. WPCF)
     Personal Correspondence from E. J. Kirsh to Warren S. Thompson,
     1972.

95.  Fisher, C. W., "Hoppers' Experience Regarding Irrigation of
     Industrial Effluent Waters and Especially Wood Treating Plant
     Control in the Wood Preserving Industry (W. S. Thompson, Editor),
     Mississippi Forest Products Laboratory, Mississippi State
     University, State College, Mississippi, pp 232-248, 1971.

96.  American Petroleum Institute, Manual on Disposal of Refinery
     Wastes. Vol. I_. Wastewater Containing Oil (6th Edition), 92 pp,
     1960.

97.  Montes, G. E., Allen, D. L., and Showell, E, B., "Petrochemical
     Waste Treatment Problems," Sewage Ind. Wastes, 28:507-512, 1956.

98.  Biczysko, J. and Suschka, J., "Investigations on Phenolic
     Wastes Treatment in an Oxidation Ditch," in Advances in Water
     Pollution Research, Munich Conference, Vol. 2, pp 285-289, Pergamon
     Press, New York, N.Y, 1967,

99.  Skogen, D. B., "Treat HPI Wastes with Bugs," Hydrocarbon Pro-
     cessing, 46(7):105, 1967.

100.  Crane, L. E., "An Operational Pollution Control System for
      Abatement and Control in the Wood Preserving Industry, (W. S.
      Thompson, Editor) Mississippi Forest Products Laboratory,
      Mississippi State University, State College, Mississippi, pp 261-
      270, 1971.

101.  Gaudy, A. F., Jr., Scudder, R., Neeley, M. M., and Perot, J. J.,
      "Studies on the Treatment of Wood Preserving Wastes," Paper
      presented at 55th National Meeting, Amer. Inst. Chem. Eng.,
      Houston, Texas, 1965.

102,  Gaudy, A. F., Jr., "The Role of Oxidation Ponds in A Wood
      Treating Plant Waste Abatement Program," Proceedings, Conference
      On Pollution Abatement and Control i_n_ the Wood Preserving Industry
      TW". S. Thompson, Editor) Mississippi Forest Products Laboratory,
      Mississippi State University, State College, Mississippi, pp 150-
      164, 1971.
                                 308

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103.  Vaughan,  J.  C.,  "Problems in Water Treatment," Jour.,  American
      Water Works  Association,  56(5):521, 1964.

104.  Woodward, E. R.,  "Chlorine Dioxide for Water Purification!11
      Jour. Pennsylvania Water  Works Operators'  Assoc.,  28:33,  1956.

105.  Glabisz,  0., "Chlorine Dioxide Action on Phenol Wastes,"  Chem.
      Abs., 65:10310,  1966.

106.  Manufacturing Chemists Association, "The Effect of Chlorination
      on Selected  Organic Chemicals," Environmental Protection  Agency,
      Water Pollution  Control Research Series. Project 12020 EXE,  104
      pages, 1972.

107.  Thompson, W. S.  and Dust, 0. V., "Pollution Control in the Wood
      Preserving Industry. Part 2. Inplant Process Changes and  Sanita-
      tion," Forest Prod. J.. 22(7):42-47, 1972.

108,  American Public  Health Association, Standard Methods for  the
      Examination of Water and Vlastewater, 12th Ed., New York,  1965.

109.  Corbitt,  R.  A.,  "The Wood Preserving Industry's Water Pollution
      Control Responsibility in Georgia and Neighboring  States," Pro-
      Wood Preserving  Industry, (W. S. Thompson, Editor) Mississippi
      Forest Products  Laboratory, Mississippi State University, State
      College,  Mississippi,  pp  19-35, 1971.

110.  Inhols, R. S. and Ridenour, G. M., "The Elimination of Phenolic
      Tastes by Chloro-Oxidation," Mater and Sewage Works, 95:187, 1949,

111.  Ettinger, M. B.,  and Ruchoft, C. C.» "Effect of Stepwise
      Chlorination on  Taste-and-Color-Producing Intensity of Some
      Phenolic Compounds," Jour. American Water Works Association.
      43:651, 1951.

112.  Burttschell, R.  H., "Chlorine Derivatives of Phenol Causing Taste
      and Odor," Jour.  American Water Works Assoc., 51:205-214, 1959.

113.  Eisenhaeur,  H. R., "Oxidation of Phenolic Wastes," Jour.  Water
      Pollution Control Federation. 36(9):1H6-1128, 1964.

114.  Niegowski, S. J., "Destruction of Phenols by Oxidation with
      Ozone," Ind. Eng. Chem.,  45(3):632-634, 1953.

115.  Niegowski, S. J., "Ozone  Method for Destruction of Phenols
      in Petroleum Wastewater," Sewage and Ind.  Wastes,  28(10):
      1266-1272, 1956.

116.  Gloyna, E. F. and Malina, J. F., Jr., "Petrochemical Wastes
      Effects on Water, Part 3.  Pollution Control," Ind. Water and
      Wastes (January  - February, pp 29-35, 1962.

117.  Gloyna, E. F., and Malina, J. F., Jr., "Petrochemical  Waste
                                309

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      Effects on Water, Part 2.  Physiological Characteristics/1
      Ind. Water and Wastes, (November-December) pp 157-161, 1962.

118.  Gould, M. and Taylor, J., "Temporary Water Clarification System,"
      Chem. Eng. Progress, 65(12):47-49, 1969.

119.  Thomas E. Gates & Sons, Inc., Personal Correspondence to
      Environmental Engineering, Inc., Gainesville, Florida, June,
      1973.

120.  Effenberger, Herman K., Gradle, Don D. and Tomany, James P.,
      Division Conference of TAPPI, Houston, Texas, May, 1972.
121.  Powell, S. T., Water Conditioning.ForJndustry, McGraw-Hill
      York, 1954.
New
122.  Patterson, J. W., and Minear, R, A., "Wastewater Treatment
      Technology," Illinois Institute for Environmental Quality, Report
      No. PB-204521, 280 pages, 1971.

                          ADDITIONAL REFERENCES

Back, Ernst, L. and Larsson, Stig A,, "Increased Pulp Yield as Means
     Means of Reducing the BOD of Hardboard Mill Effluent," Swedish
     Paper Journal, October 15, 1972.

Boydston, James R., "Plywood and Sawmill Liquid Waste Disposal," Forest
     Products Journal, Vol. 21, No. 9, September 1971.

Fisher, C. W., "Soil Percolation and/or Irrigation of Industrial Effluent
     Waters—Especially Wood Treating Plant Effluents," Forest Products
     Journal, Vol. 21, No. 9, September 1971.

Freeman, H.  G. and Grendon, W. C., "Formaldehyde Detection and Con-
     trol in the Wood Industry," Forest Products Journal, Vol. 21, No.
     9, September, 1971.

Gehm, Harry, State-of-the-Art Review of Pulp and Paper Waste Treatment
     Office of Research and Monitoring, U. S. Environmental
     Protection Agency, Washington, D. C., April, 1973.

Gehm, Harry W. and Lardieri, Nicholas J., "Waste Treatment in
     the Pulp, Paper, and Paperboard Industries," Sewage and
     Industrial Wastes, Vol. 28, No. 3, March, 1956.

Glossary - Water and Waste Water Control Engineering, Prepared by
     Editorial Board representing American Public Health Association,
     American Society of Civil Engineers, American Water Works
     Association, Water Pollution Control Federation, 1969.

Gould, M. and Taylor» J., "Temporary fcater Clarification System,"
     Chemical Engineering Progress, Vol. 65, No. 12, December, 1969.

Groth, Bertil, Wastewater from Fiberboard Mills, Annual Finnish Paper
                                310

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     Engineers'  Association Meeting, Helsinki, April  12, 1962.

Hansen, George,  (Task Force Chairman) Log Storage and Rafting in
     Public Waters. Pacific Northwest Pollution Control Council,
     August, 1971.

Hoffbuhr, Jack,  Blanton, Guy, and Schaumburg, Frank,  "The Character
     and Treatability of Log Pond Waters," Industrial Waste, July-
     August, 1971.

Kleppe, Peder J., and Rogers, Charles N., Survey of Water Utilization
     and Waste Control Practices in the Southern Pulp and Paper
     Industry, Water Resources Research Institute, University of
     North Carolina, June, 1970.

Leker, James E., and Parsons, Ward C.s "Recycling Water - A Simple
     Solution?," Southern Pulp and Paper Manufacturer, January,
     1973.

Luxford, R. F.,  and Trayer, George W., (Forest Products Laboratory,
     University of Wisconsin) Wood Handbook, U. S. Department of
     Agriculture, Washington, D.C. 1935.

Malo, Bernard A., "Semichemical Hardwood Pulping and Effluent
     Vol. 39, No. 11, November 1967.

McHugh, Robert A., Miller, LaVerne SI, and Olsen, Thomas E., The
     In the Pacific Northwest, Division of Sanitation and Engineer-
     ing, Oregon State Board of Health, Portland, 1964.

Parsons, Ward C., "Spray Irrigation of Wastes from the Manufacture
     of Hardboard," Purdue Wastewater Conference, 1967.

Parsons, Ward C., and Woodruff, Paul H., "Pollution Control: Water
     Conservation, Recovery, and Treatment," TAPPI, 53:3, March,
     1970.

Quirk, T. P., Olson, R. C., and Richardson, G., "Bio-Oxidation of
     Concentrated Board Machine Effluents," Journal,  Water Pollu-
     tion Control Federation, Vol. 38, No. 1, 1966.

Reinhall, Rolf,  and Vardheim, Steinar, Experience with the DKP Press,
     Appit'a Conference, Australia, March, 1965.

Robinson, J. G., "Dry Process Hardboard," Forest Products Journal,
     July, 1959.

Sawyer, Clair N., Chemistry for Sanitary Engineers, Second Edition,
     McGraw-Hill, New York, 1967.

Shreve, Norris,  Chemical Process Industries, McGraw-Hill, New York,
     1967.

Timpe, W. G., Lang, E., and Miller, R. L., Kraft Pulping Effluent
                                311

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     Treatment and Refuse -State-of-the-Art," Office of Research and
     Monitoring, U. S. Environmental Protection Agency, Washington,
     D. C., 1973.

Tretter, Vincent J., Or., "Pollution Control Activities at Georgia-
     Pacific," Forest Products Journal. Vol. 21, No. 9, September,
     1971.

Wood Products Sub-Council, "Principal Pollution Problems Facing
     the Solid Wood Products Industry," Forest Products Journal.
     Vol. 21, No. 9, September, 1971.
                                  312

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                            SECTION XIV

                             GLOSSARY


"Act" - The Federal Water Pollution Control Act Amendments of 1972.

Activated  Sludge  -  Sludge  floe produced in raw or settled waste
water by the growth of zoogleal bacteria and other organisms in the
presence  of  dissolved  oxygen  and  accumulated   in   sufficient
concentration by returning floe previously formed.

Activated  Sludge  Process  -  A  biological  waste water treatment
process in which a mixture of waste water and activated  sludge  is
agitated   and  aerated.   The  activated  sludge  is  subsequently
separated  from  the  treated  waste  water    (mixed   liquor)   by
sedimentation and wasted or returned to the process as needed.

Aerated Lagoon - A natural or artificial waste water treatment pond
in  which mechanical or diffused-air aeration is used to supplement
the oxygen supply.

Aerobic - condition in which free, elemental-, oxygen is present,

Additive - Any material introduced prior to the final consolidation
of a board to improve some  property  of  the  final  board  or  to
achieve  a  desired  effect  in  combination with another additive.
Additives  include  binders  and  other  materials.   Sometimes   a
specific  additive may perform more than one function.  Fillers and
preservatives are included under this term.

Air Drying - Drying veneer by placing the veneer in stacks open  to
the  atmosphere, in such a way as to allow good circulation of air.
It is  used only in the production of low quality veneer.

Air-felting - Term applied to the forming of a fiberboard  from  an
air suspension of wood or other cellulose fiber and to the arrange-
ment of such fibers into a mat for board.

Anaerobic - Condition in which free elemental oxygen is absent.

Asplund  Method - An attrition mill which combines the steaming and
defibering in one unit in a continuous operation.

Attrition Mill - Machine which produces particles by forcing  coarse
material, shavings, or pieces of wood between a  stationary   and  a
rotating disk, fitted with slotted or grooved segments.

Back  - The side reverse to the face of a panel, or the poorer side
of a panel in any grade of plywood that has a face and back.

Bag Barker - See debarker.
                               313

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Blue Stain - A biological reaction  caused  by  a  stain  producing
fungi  which  causes  a blue discoloration of sapwood, if not dried
within a short time after cutting.

Biological Waste water Treatment - Forms of waste  water  treatment
in   which  bacterial  or  biochemical  action  is  intensified  to
stabilize,  oxidize,  and  nitrify  the  unstable  organic   matter
present.    Intermittent  sand  filters,  contact  beds,  trickling
filters,  aerated  lagoons  and  activated  sludge  processes   are
examples.

Slowdown  -  The  removal  of  a  portion  of  any process water to
maintain the constituents of the solution at desired levels.

BODS -  Biochemical  Oxygen  Demand  is  a  measure  of  biological
decomposition   of  organic  matter  in  a  water  sample.   It  is
determined by measuring the oxygen required  by  microorganisms  to
oxidize  the  organic contaminants of a water sample under standard
laboratory conditions.  The standard conditions include  incubation
for five days at 20°C.

Bolt - A short log cut to length suitable for peeling in a lathe.

Boultonizing  -  A conditioning process in which unseasoned wood is
heated under a partial vacuum to reduce its moisture content  prior
to injection of the preservative.

Casein - A derivative of skimmed milk used in making glue.

Caul - A steel plate or screen on which the formed hardboard wetlap
mat is placed for transfer to the press, and on which the mat rests
during the pressing process.

CCA-Type  Preservative - Any one of several inorganic salt formula-
tions based on salts of copper, chromium, and arsenic.

Chipper - A machine which reduces to chips.

Clarifier - A unit of which the primary purpose is  to  reduce  the
amount of suspended matter in a liquid.

Clipper  -  A machine which cuts veneer sheets to various sizes and
also may remove defects.

Closed Steaming - A method of steaming in which the steam  required
is  generated  in the retort by passing steam through heating coils
that are covered with water.  The water used for  this  purpose  is
recycled.

COD - Chemical Oxygen Demand.  Its determination provides a measure
of  the  oxygen  demand  equivalent  to that portion of matter in a
sample which is susceptible  to  oxidation  by  a  strong  chemical
oxidant.

                               314

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Coil  Condensate - The condensate formed in steam lines and heating
coils.

Cold .Pressing - See pressing.

Commercial Veneer - See veneer; hardwood.

Composite Board - Any combination  of  different  types  of  board,
either with another type board or with another sheet material.  The
composite  board may be laminated in a separate operation or at the
same time as the board is pressed.  Examples  of  composite  boards
include  veneer-faced  particle  board,  hardboard-faced insulation
board and particle board, and metal-faced hardboard.

Conditioning - The practice of heating logs  prior  to  cutting  in
order  to  improve  the  cutting properties of the wood and in some
cases to facilitate debarking.

Container Veneer - See veneer.

Cooling Pond - A  water  reservoir  equipped  with  spray  aeration
equipment  from  which  cooling  water  is drawn and to which it is
returned.
£ore - Also referred to as the center
plywood panel.
The innermost segment of  a
Creosote - A complex mixture of organic materials obtained as a by-
product  from coking and petroleum refining operations that is used
as  a wood preservative.
Crossband, v - To  place the grain of the layers of veneer at
angles  in order to minimize swelling and shrinking.
                      right
Crossband,  n  -  The   layers of veneer  whose grain direction  is at
right  angles to that of the  face   piles,   applied  particularly  to
five-ply  plywood and  lumber core  panels,  and more generally to all
layers between the core and  the faces.

Curing - The physical-chemical change that takes  place  either  to
thermosetting  synthetic  resins  (polymerization) in the hot presses
or  to  drying oils  (oxidation) used  for   oil-treating  board.   The
treatment to produce that change.

Cutterhead  Barker - See debarker.

Cylinder -  See retort.

Cylinder  Condensate   - Condensation that forms on the walls of the
retort during steaming operations.   Also,  of  process   in   which
unseasoned  wood is subjected to exposure to aft atmosphere of  steam
to  reduce its moisture content and improve its pereability.
                               315

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Debarker - Machines which remove bark from logs.  Debarkers may  be
wet or dry, depending on whether or not water is used in the opera-
tion.  There are several types of debarkers including drum barkers,
ring  barkers,  bag  barkers,  hydraulic  barkers,  and  cutterhead
barkers.  With the exception  of  the  hydraulic  barker,  all  use
abrasion  or  scraping  actions  to remove bark.  Hydraulic barkers
utilize high pressure streams of  water.   All  types  may  utilize
water,  and  all  wet debarking operations may use large amounts of
water and produce effluents with high solids concentrations.

Decay - The decomposition of wood caused by fungi.

Defiberization - The reduction of wood materials to fibers.

Delamination - Separation of the plies of a piece of plywood.

Digester - 1)  Device for conditioning  chips  using  high  pressure
steam,  2)  A tank in which biological decomposition (digestion) of
the organic matter in sludge takes place.

Disc Pulpers - Machines which produce pulp  or  fiber  through  the
shredding action of rotating and stationary discs.

DO  - Dissolved Oxygen is a measure of the amount of free oxygen in
a water sample.

Drum Barker - See debarker.

Dry-clipping - Clipping of veneer which takes place after drying.

Dryers - Most commonly long chambers equipped with rollers on belts
which advance the veneer longitudinally through the chamber.   Fans
and  heating  coils are located on the sides to control temperature
and humidity.  Lumber kilns are  also  sometimes  used.   See  also
veneer drying.

Dry*felting - see air-felting.

Durability  -  As  applied to wood, its lasting qualities or perma-
nence in service  with  particular  reference  to  decay.   May  be
related directly to an exposure condition.

Snd-checking - Cracks which form in logs due to rapid drying out of
the ends.

Exterior - A term frequently applied to plywood, bonded with highly
resistant glues, that is capable of withstanding prolonged exposure
to severe service conditions without failure in the glue bonds.

Face  -  The better side of a panel in any grade of plywood calling
for a face and back; also either side of a panel where the  grading
rules draw no distinction between faces.

Face Veneer - see veneer; hardwood.
                              316

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Fiber  -  The  slender  thread-like  elements  of. wood  or similar
cellulosic material,  which,  when  separated  by  chemical  and/or
mechanical means* as in pulping, can be formed into fiberboard.


Fiberboard  -  A sheet material manufactured from fibers of wood or
other ligno-cellulosie materials with  the  primary  bond  deriving
from  the  arrangement  of  the  fibers and their inherent adhesive
properties.  Bonding agents or other materials may be added  during
manufacture  to  increase  strength,  resistance to moisture, fire,
insects, or decay,  or  to  improve  some  other  property  of  the
product.  Alternative spelling:  fibreboard.

Fiber .Preparation  -  The reduction of wood to a fibrous condition
for . hardboard.. manufacture,  utilising  mechanical,  thermal,   or
explosive methods.

Figure  --  Decorative natural designs in wood which are valuable in
the furniture and cabinet making industries.

Finishing *• The final preparation of the  product.   Finishing  may
include redrying, trimming, sanding,.sorting, molding, and storing,
depending On the operation and product desired.

Fire Retardant - A  formulation of inorganic salts that imparts firo
resistance  when injected into wood in high concentrations.  Flitch
- A part of a log which has been so sectioned as to best display  a
particular grain configuration or figure ,in the resulting veneer.

Flotation  *  The raising of suspended matter to the surface of the
liquid, in a tank  as  scum1—by  aeration,  the  evolution  of  gas,
chemicals, electrolysis, heat, or bacterial decomposition.

Formation  fForming) - The felting of Wood or other cellulose fibers
into  a  mat  for hardboard.  Methods employed:  airfelting and wet
felting.
Glue - Adhesive which is used to  join
plywood..  There are three types  most
,o£ plywood, depending on raw material
They   are   1)  protein,  2)  phenol
formaldehyde.  The  first is extracted
thermoplastic while the other two are
veneer sheets  together  into
often used in the manufacture
and intended  product  usage.
 formaldehyde,  and  3)   urea
from plants and  animals  and
synthetic and thermosetting.
Glue Spreaders - Means of applying  glue  to veneer,  either by  use  of
power driven rollers or  spray curtain-coater applicators.
J3lue_ Line  -  The part of the plywood  production process where  the
glue  is applied to the veneer and the plywood layers  assembled.

GPP - Gallons per day.

GPM - Gallons per minute.
                              317

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Grading — The selection and categorization of different  woods  and
wood products as to its suitability for various uses.  Criteria for
selection  include such features of the wood as color, defects, and
grain direction.

Grain - The direction, size, arrangement,  and  appearance  of  the
fibers in wood or veneer.

Green  Clipper - A clipper which clips veneer prior to being dried.
Green Stock - Unseasoned wood.

Hardboard - A compressed fiberboard of 0.80 to 1.20 g/cm3 (50 to 75
pounds per cubic foot) density.  Alternative  term:   fibrousfelted
hardboard.

Hardboard  Press  -  Machine which completes the reassembly of wood
particles and welds them into a tough, durable, grainless board.
Hardwood - wood from  deciduous  or  broad-leaf  trees.
Hardwoods
include  oak,  walnut,  lavan,  elm, cherry, hickory, pecan, maple,
birch, gum, cativo, teak, rosewood, and mahogany.

Heartwood - The inner core of a wood  stem  composed  of  nonliving
cells  and  usually  differentiated from the outer enveloping layer
(sapwood) .

Heat-treated Hardboard -  Hardboard  that  has  been  subjected  to
special  heat treatment after hot-pressing to increase strength and
water resistance.

Holding Ponds — See impoundment.

Hot Pressing - See pressing.

Humidif ication - The seasoning operation  to  which  newly  pressed
hardboard  are  subjected  to  prevent  warpage  due  to  excessive
dryness.

Hydraulic Barker - See debarker.

Impoundment - A pond, lake, tank, basin,  or  other  space,  either
natural  or  created  in  whole  or  in  part  by  the  building of
engineering structures, which is used for storage, regulation,  and
control of water, including waste water.

Kiln Drying - A method of preparing wood for treatment in which the
green  stock  is  dried  in  a  kiln under controlled conditions of
temperature and humidity.

KIld-N - Kjeldahl Nitrogen - Total organic nitrogen plus ammonia of
a sample.

Lagoon - A pond containing raw or partially treated waste water  in
which aerobic or anaerobic stabilization occurs.
                                  318

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Leaching  -  Mass transfer of chemicals to water from wood which is
in contact with it.

Log.Bed - Device which holds a log and moves it up and down past  a
stationary blade which slices sheets of veneer,

MGD - Million gallons per day.

mg/1  -  Milligrams  per liter (equals parts per million, ppm, when
the specific gravity is 1.0) .

Modified Steaming - A technique for conditioning logs  which  is  a
variety  of  the  steam  vat  process  in that steam is produced by
heating water with coils set in the bottom of the vat.

Moisture - water content of wood or a timber product expressed as a
percentage of total weight or as percentage of the  weight  of  dry
wood.

Non-Pressure  Process	p-  A  method of treating wood at atmospheric
pressure in which the wood is simply soaked in  hot  or  cold  pre-
servative.

Nutrients  -  The  nutrients  in  contaminated  water are routinely
analyzed to characterize the food available for  microorganisms  to
promote organic decomposition.  They are:

            Nitrogen. Ammonia  (NH^) , mg/1, as N

            Nitrogen, Total Kleldahl  (NH3^ and Organic N) ,
                 mg/1, as N

            Nitrogen Nitrate  (NO3j , mg/1, as N

            Total Phosphate, mg/1 as P

            Ortho Phosphate, mg/1 as P

Oil-Recovery  System  -  Equipment  used  to reclaim oil from waste
water.
Oily	Preservative  —  Pentachlorophenol-petroleum   solutions
creosote in the various forms in which it is used.
and
Open  steaming  - A method of steam conditioning in which the  steam
required is injected directly into the cylinder.

Pearl Benson Index '- A measure of color producing substances.

Pentachlorophenol - A chlorinated phenol with the  formula  c6ci5_OH
and  formula  weight of  266.35 that is used  as  a wood preservative.
Commercial grades of this chemical  are  usually  adulterated  with
-tetrachlorophenol to improve its solubility.
                               319

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2H  -  pH  is  a  measure  of  the acidity or alkalinity of a water
sample.  It is equal to  the  negative  log  of  the  hydrogen  ion
concentration.

Phenol - The simplest aromatic alcohol.

Pitch - An organic deposit composed of condensed hydrocarbons which
forms on the surface of dryers.

Plant Sanitation - Those aspects of plant housekeeping which reduce
the  incidence  of  water  contamination   resulting from equipment
leaks, spillage of preservative, etc.

Plywood - An assembly of a number of layers of  wood,  or  veneers,
joined  together  by means of an adhesive.  Plywood consists of two
main types:

1)  hardwood plywood - has a face ply of hardwood and is  generally
used for decorative purposes.

2)   softwood  plywood  — the veneers typically are of softwood and
the usage is generally for construction and structural purposes.

Plywood Pressing Time - The amount of time that  plywood  is  in  a
press.   The time ranges from two minutes to 24 hours, depending on
the temperature of the press and the type of glue used.

Point Source - A discrete source of pollution.

Pressing - The step in the production operation in which sheets are
subjected to pressure for the purpose of  consolidation.   Pressing
may  be accomplished at room temperature  (cold pressing) or at high
temperature (hot pressing).

Press Pit — A sump under the hardboard press.

Pressure Process - A process in which wood preservatives  and  fire
retardants are forced into wood using air or hydrostatic pressure.

Radio  Frequency Heat - Heat generated by the application of an al-
ternating electric current,  oscillating  in  the  radio  frequency
range,  to  a dielectric material.  In recent years this method has
been used to cure synthetic resin glues.

Resin - Secretions of saps of certain plants or trees.   It  is  an
oxidation  or polymerization product of the terpenes, and generally
contains "resin" acids and ethers.

Retort - A steel vessel in which wood products are pressure impreg-
nated  with  chemicals  that  protect  the  wood  from   biological
deterioration or that impart fire resistance.  Also called -treating
cylinder.

Ring barker - See detarfcer.
                               320

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Rotary lathing - See veneer cutting.

Roundwood - Wood that is still in the form of a log, i.e. round.

Saw  Kerf - Wastage of wood immediately adjacent to a saw blade due
to the cut-cleaning design of the blade,  which  enlarges  the  cut
slightly on either side.

Sawn Veneer - See veneer cutting,

Sedimentation  Tank - A basin or tank in which water or waste water
containing settleable solids is retained to  remove  by  gravity  a
part of the suspended matter.

Segment  Saw  - A modern veneer saw which consists of a heavy metal
tapering flange  to  which  are  bolted  several  thin,  steel  saw
segments   along   its   periphery.    The   segment  saw  produces
considerably less kerf than conventional circular saws.

Semi-Closed Steaming - A method of steam conditioning in which  the
condensate  formed  during  open steaming is retained in the retort
until sufficient condensate accumulates to cover  the  coils.   The
remaining steam required is generated as in closed steaming.

Settling  Ponds  -  A  basin  or tank in which water or waste water
containing settable solids is retained to remove by gravity a  part
of   the   suspended  matter.   Also  called  sedimentation  basin,
sedimentation tank, settling tank.
Slicing - See veneer cutting.

Sludge - The accumulated solids separated  from  liquids,
water or waste water, during processing.
such  as
jimooth-two-sides   (S-2-Si  -  Hardboard,  or  other  fiberboard  or
particle board produced when a board is pressed from a dry  mat  to
give a  smooth surface oh both sides.

Softwood - Wood from evergreen or needle bearing trees.

Soil, Irrigation - A method of land  disposal in which waste water is
sprayed on a prepared field.  Also  referred to as soil percolation.

Solids  -  Various types of solids  are commonly determined on water
samples. .These types of solids are:

            Total Solids  (TS) - The material left after eva-
            poration and drying a sample at 103-105°C.

            Total suspended solids  (TSS) - The material removed from
            a sample filtered through a standard glass fiber
            filter.  Then it is dried at  1G3-105°C.

            Dissolved Solids  (PS) - The difference between
                              321

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            the total and suspended solids.

            Volatile Solids (VS1  - The material which is lost
            when the sample is heated to 550°C.

            Settleable solids - The material which
            settles in an Immhoff cone over a period of time.

Spray Evaporation - A method of waste water disposal in which water
is sprayed into the air to expedite evaporation.

Spray Irrigation - A method of  disposing  of  some  organic  waste
waters  by  spraying them on land, usually from pipes equipped with
spray nozzles.

Steam Conditioning - A conditioning method in which unseasoned wood
is subjected to an atmosphere of steam at about  120°C   (249°F)  to
reduce  its  moisture  content  and  improve  its permeability pre-
paratory to preservative treatment.

Steaming  - Treating wood material with steam to soften it.

Sump -  (1) A tank or pit  that  receives  drainage  and  stores  it
temporarily,  and from which the drainage is pumped or ejected,  (2)
A tank or pit that receives liquids.

Synthetic Resin  (Thermosetting) - Artificial resin  (as  opposed  to
natural)  used  in board manufacture as a binder.  A combination of
chemicals which can be polymerized,  e.g.  by  the  application  .of
heat,  into a compound which is used to produce the bond or improve
the bond in a fiberboard or particle board.  Types usually used  in
board  manufacture  are  phenol formaldehyde, urea formaldehyde, or
melamine formaldehyde.

Tapeless  Splicer  -  A  machine  which  permits  the  joining   of
individual  sheets  of  veneer without the use of tape.  Individual
sheets are glued edge to edge, and cured, thus saving on tape costs
and sanding time during finishing.

Taping Machine - A machine which joins indivdual sheets  of  veneer
by  taping  them together.  The tape is later sanded off during the
finishing operations.

Tempered Hardboard  -  Hardboard that has been specially treated in
manufacture  to  improve  its  physical  properties   considerably.
Includes,    for   example,   oil-tempered   hardboard.    Synonym:
superhardboard.

Thermal Conductivity - The quantity of heat which   flows  per  unit
time  across unit area of the subsurface of unit thickness when the
temperature of the faces differs by one degree.

Thermosetting - See synthetic resin.
                               322

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TOC - Total Organic  carbon  is  a  measure  of  the  organic  con-
tamination  of  a  water  sample.  It has an empirical relationship
with the biochemical and chemical oxygen demands,

T-PO4-P _ Total phosphate as phosphorus.

Turbidity - (1) A condition in water or waste water caused  by  the
presence  of  suspended  matter,  resulting  in  the scattering and
absorption of light rays.  (2)  A measure  of  the  fine  suspended
matter in liquids.   (3)  An analytical quantity usually reported in
arbitrary  turbidity  units  determined  by  measurements  of light
diffraction.
                                                     vacuum  period
Vacuum water - Water extracted from wood during
following steam conditioning.

Vapor_ Drying - A process in which unseasoned wood is heated in the
hot vapors of an organic solvent,  usually  xylene,  to  season  it
prior to preservative treatment.

Vat  -  Large  metal  container in which logs are "conditioned," or
heated prior to cutting.  The two basic methods for heating are  by
direct  steam  contact in "steam vats," or by steam heated water in
"hot water vats."

Veneer - A thin sheet of wood  of  uniform  thickness  produced  by
peeling,  slicing, or sawing logs, bolts, or flitches.  Veneers may
be categorized as either hardwood or softwood depending on the type
of woods used and the intended purpose.

            softwood veneer is used in the manufacture
            of softwood plywood and in some cases the
            inner plies of hardwood faced plywood.

            Hardwood Veneer can be categorized according
            to use, the three most important being:

             (1)  face veneer - the highest quality used
                 to make panels employed in furniture
                 and interior decoration.

             (2)  commercial veneer - used for crossbands,
                 cores, backs of plywood panels and con-
                 cealed parts of furniture.

             (3)  container veneer - inexpensive veneers
                 used in the making of crates, hampers,
                 baskets, kits, etc.

Veneer Cutting - There are four basic methods:

             (1)  rotary lathing - cutting continuous strips
                by the use of a stationary knife and a lathe.
             (2) slicing - consists of a stationary knife and
                               323

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                an upward and downward moving log bed.  On
                each down stroke a slice of veneer is cut.
             (3) stay log - a flitch is attached to a "stay
                log," or a long, flanged, steel casting
                mounted in eccentric chucks on a conventional
                lathe.
             (4) sawn veneer - veneer cut by a circular type
                saw called a segment saw.  This method
                produces only a very small quantity of veneer
                (see also "segment saw").

Veneer Drying - Freshly cut veneers  are  ordinarily  unsuited  for
gluing  because of their wetness and are also susceptible to molds,
fungi, and blue stain.  Veneer is usually dried, therefore, as soon
as possible, to a moisture content of about 10 percent.

Vene'er Preparation - A series of minor operations including grading
and  matching,  redrying,  dry-slipping,   joining,   taping,   and
splicing,  inspecting,  and repairing.  These operations take place
between drying and gluing.

Water-Borne Preservative -  Any  one  of  several  formulations  of
inorganic  salts,  the  most  common  which  are  based  on copper,
chromium, and arsenic.
Water Balance - The water gain  (inflows) of
loss  (outflows) .

Wet Barkers - See debarker.
a  mill  versus  water
Wet-Felting  -  Term  applied to the forming of a  fiberboard from a
suspension of pulp in water usually on a  cylinder or  Fourdrinier
machine;  the  interfelting  of wood fibers from a water suspension
into a mat for board.

Wet Process - see Wet Felting.

Wet Scrubber - An air pollution control device which  involves  the
wetting of particles in an air stream and the impingement  of wet or
dry particles on collecting surfaces, followed by  flushing.

Wood  Extractives  -  A  mixture  of  chemical compounds,  primarily
organics, removed from wood.

Wood Preservatives -  A  chemical  or  mixture  of chemicals   with
fungistatic  and insecticida'l properties that is injected  into  wood
to protect it from biological deterioration.
                              324

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                                                  TABLE 71

                                              CONVERSION TABLE
CO
ro
tn
                 MULTIPLY
acre
acre - feet
board foot
British Thermal
  Unit
British Thermal
  Unit/pound
cubic feet/minute
cubic feet/second
cubic feet
cubic feet
cubic inches
degree Fahrenheit
feet
gallon
gallon/minute
horsepower
inches
inches of mercury
pounds
pounds/cubic ft
million gallons/day
mile
pound/square inch
  (guage)
square feet
square inches
1000 board ft
tons (short)

yard
                                ABBREVIATION

                                  ac
                                  ac ft
                                  bd ft
                                  BTU

                                  BTU/lb
      by

 CONVERSION

   0.405
1233.5
  12.0
   0.252

   0.555
                                                                      TO OBTAIN
ABBREVIATION

   ha
   cu m
   cu ft
   kg cal
   kg
cfm
cfs
cu ft
cu ft
cu in
OF
ft
gal
gpn
hp
in
in Hg
Oto
Ib/cu ft
mgd
mi
psig
sq ft
sq in
1000 bd ft
ton
0.028
1.7
0.028
28.32
16.39
0.555 <°F-32}*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
16.05
3,785
1.609
(0.06805 psig +1)*
0.0929
6.452
2.36
0.907
cu nyfriin
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
on
atm
kg
kg/cu m
cu m/day
km
atm
sq m
sq cm
cu m
kkg
                                  yd
   0.9144
                      m
hectares
cubic meters
cubic feet
kilogram-calories

kilogram calories/
 kilogram
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
kilowatts
centimeters
atmospheres
kilograms
kilograms/cubic meters
cubic meters/day
kilometer
atmospheres
 (absolute)
square centimeters
square centimeters
cubic meters
metric tons
 (1000 kilograms)
meters
           *Actual conversion, not a multiplier

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