United States
hnVIPoTlrnental Protection
Agency
Effluent Guidelines Division
EPA 440-1-80-091-A
June 1980
Water and Waste Management
Development
Document for
Effluent Limitations
Guidelines and
Standards for the
Metal Finishing
                Draft
Point Source Category

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      DRAFT DEVELOPMENT DOCUMENT

               for the

           METAL FINISHING
        POINT SOURCE CATEGORY
          Douglas M. Costle
            Administrator

           Eckardt C. Beck
       Assistant Administrator
    for Water  and Waste  Management

           Steven Schatzow
    Deputy Assistant  Administrator
   for Water  Planning and Standards
                      \
             S

             %
          Robert B.  Schaffer
Director, Effluent Guidelines Division

          G. Edward Stigall
   Chief,  Inorganic Chemicals Branch

           Richard J.  Kinch
        Senior  Project Officer

           Dwight Hlustick
           Project Officer
              MAY,  1980
     Effluent Guidelines Division
 Office of Water and Waste Management
U. S.  Environmental Protection Agency
       Washington,  D. C.  20460
                    Prepared under EPA Contract: 68-01-5827
                    by Hamilton Standard, Division of  United
                    Technologies

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                     TABLE OF CONTENTS

                Title                               Page

  I    CONCLUSIONS AND SUMMARY                      1-1

 II    RECOMMENDATIONS                              II-l

III    INTRODUCTION                                 III-l

            LEGAL AUTHORITY                         III-l

            GUIDELINE DEVELOPMENT SUMMARY           III-3

                 Sources of Industry Data           III-4

                 Utilization of Industry Data       111-15

            INDUSTRY DESCRIPTION                    111-15

                 Unit Operations Descriptions       111-20

 IV    INDUSTRY CATEGORIZATION                      IV-1

            INTRODUCTION                            IV-1

            CATEGORIZATION BASIS                    IV-1  i/

            EFFLUENT LIMITATION BASE                IV-4

                 Selection of Limitation Parameter  IV-5

  V    WASTE CHARACTERIZATION                       V-l

            INTRODUCTION                            V-l

            WATER USAGE IN THE METAL FINISHING
             CATEGORY

                 Water Use Summary                  V-3

            WASTE CHARACTERISTICS FROM METAL
             FINISHING UNIT OPERATIONS

            CHARACTERISTICS OF SUBCATEGORY WASTE
             STREAMS                                  Jy

                 Common Metals Subcategory          V-43

                 Precious Metals Subcategory        V-43

                 Complexed Metals Subcategory       V-43

                 Cyanide Category                   V-43  --

                 Hexavalent Chromium Subcategory    V-43

                 Oil Subcategory                    V-43
                 Solvent Subcategory                V-49

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                 TABLE OF CONTENTS (CON'T)

                Title                               Page

 VI    SELECTION OF POLLUTANT PARAMETERS            VI-1

            INTRODUCTION                            VI-1

            SELECTION RATIONALE                     VI-1

                 Toxic Organic Pollutants           VI-1

                 Toxic Non-Organic Pollutants       VI-8

                 Non-Toxic Metals                   VI-8

                 Other Pollutants                   VI-15

            POLLUTANT PARAMETERS SELECTED           VI-15

                 Common Metals Subcategory -        vi-16
                  Selected Pollutant Parameters

                 Precious Metals Subcategory -      VT-T6
                  Selected Pollutant Parameters

                 Complexed Metals Subcategory -     vi-17
                  Selected Pollutant Parameters

                 Hexavalent Chromium Subcategory -  VT_-i 7
                  Selected Pollutant Parameters

                 Cyanide Subcategory - Selected     v  ,_
                  Pollutant Parameters

                 Oils Subcategory - Selected        vr-ift
                  Pollutant Parameters

VII    CONTROL AND TREATMENT TECHNOLOGY             VII-1

            INTRODUCTION                            VII-1

            APPLICABILITY OF TREATMENT TECHNOLOGIES VII-4

            TREATMENT OF COMMON METALS WASTES       VI1-8

                 Treatment of Common Metals Wastes- TITT 0
                  Option 1                          VII~8

                      Hydroxide Precipitation       VII-10

                      Sedimentation                 VII-14

                      Common Metals Waste Treat-
                       ment System Performance -    VII-19
                       Option 1


                          ii

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                 TABLE OF CONTENTS  (CON'T)

                Title                               Page

VII    (CON'T)

                 Treatment of Common Metals Wastes- yr-r_54
                  Option 2

                      Diatomaceous  Earth Filtration VII-54

                      Granular Bed  Filtration       VII-57

                      Common Metals Waste Treatment VTj_g2
                       System Performance - Option 2

                 Treatment of Common Metals Wastes- T7TT 0->
                  Option 3                          VII-83

                      Evaporation                   VII-83

                      Ion Exchange                  VII-88

                 Alternative Treatment Methods for  viI-95
                  Common Metals Removal

                      Electrolytic Recovery         VII-95

                      Electrodialysis               VII-101

                      Reverse Osmosis               VII-105

                      Peat Adsorption               VII-112

                      Insoluble Starch Xanthate     VI1-114

                      Sulfide Precipitation         VII-115

                      Flotation                     VII-119

                      Membrane Filtration           VII-124

            TREATMENT OF PRECIOUS METALS WASTES     VI1-126

                 Evaporation                        VII-126

                 Ion Exchange                       VII-126

                 Electrolytic Recovery              VII-128

            TREATMENT OF COMPLEXED METALS WASTES    VII-132

                 High pH Precipitation/Sedimenta-
                  tion                              VI1 -1-32


                 Alternative Treatment for Com-
                  plexed Metals Wastes              VII-133

                      Membrane Filtration           VII-133

                         ill

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                 TABLE OF CONTENTS (CON'T)

                Title                               Page

VII    (CON'T)

            TREATMENT OF HEXAVALENT CHROMIUM WASTES VII-134

                 Chemical Chromium Reduction        VII-134

                 Electrochemical Chromium Reduction VII-141

                 Alternative Hexavalent Chromium    viI-142
                  Treatment Techniques

                      Electrochemical Chromium      VII-143
                       Regeneration

                      Advanced Electrodialysis      VII-144

                      Evaporation                   VII-146

                      Ion Exchange                  VII-147

            TREATMENT OF CYANIDE WASTE              VII-148

                 Oxidation by Chrlorination         VII-148

                 Alternative Cyanide Treatment      VII-152
                  Techniques

                      Oxidation by Ozonation        VII-156

                      Oxidation by Ozone With UV
                       Radiation

                      Oxidation by Hydrogen
                       Peroxide

                      Electrochemical Cyanide
                       Oxidation

                      Chemical Precipitation        VII-165

                      Reverse Osmosis               VII-166

                      Evaporation                   VII-166

            TREATMENT OF OILY WASTES AND ORGANICS   VI1-167

                 Treatment of Oily Wastes for
                  Combined Wastewater
                         IV

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                 TABLE OF CONTENTS (CON 'JT )

                Title                               Page

VII    (CON'T)

            TREATMENT OF SEGREGATED OILY WASTES     VI1-178

                 Segregated Oily Wastes Treatment   viI-178
                  System-Option 1

                      Emulsion Breaking             VII-180

                      Skimming                      VII-184

                      Segregated Oily Wastes Treat-
                       ment System Performance -    VII-186
                       Option 1

                 Segregated Oily Wastes Treatment   viI-191
                  System-Option 2

                      Ultrafiltration               VII-193

                      Segregated Oily Waste Treat-
                       ment System Performance -    VII-197
                       Option 2

                 Segregated Oily Wastes Treatment
                  System-Option 3                   ^ii

                      Reverse Osmosis               VII-200

                      Carbon Adsorption             VII-200

                      Segregated Oily Waste Treat-
                       ment System Performance -    VII-208
                       Option 3

            ALTERNATIVE OILY WASTE TREATMENT TECH-
             MOLOGIES                               VI1 2ii

                 Coalescing                         VII-211

                 Flotation                          VII-213

                 Centrifugation                     VII-216

                 Integrated Adsorption              VII-217

                 Resin Adsorption                   VII-217

                 Ozonation                          VII-218

                 Chemical Oxidation                 VII-220

                 Aerobic Decomposition              VII-220

                 Thermal Emulsion Breaking          VII-226

            TREATMENT OF SOLVENT WASTES             VI1-229

                 Waste Solvent Control Options      VII-229
                         v

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                  TABLE OF CONTENTS  (CON'T)


                 Title                                Page

             TREATMENT OF SLUDGES                     VI1-237

                  Gravity Sludge Thickening           VII-238

                  Pressure Filtration                 VII-240

                  Vacuum Filtration                   VII-243

                  Centrifugation                      VII-247

                  Sludge Bed Drying                   VII-251

                  Sludge Disposal                     VII-254

             IN-PROCESS CONTROL TECHNOLOGY            VII-254  \/


                  Flow Reduction Through Efficient    vil-256  ^
                   Rinsing

                  Process Bath Conservation           VII-262

                  Integrated Waste Treatment          VII-267  /

                  Good Housekeeping                   VII-268

VIII    COST OF WASTEWATER CONTROL AND TREATMENT      VIII-1

             INTRODUCTION                             VIII-1

             COST ESTIMATION METHODOLOGY              VIII-1

             SYSTEM COST COMPUTATION                  VII1-4

             COST FACTORS AND ADJUSTMENTS             VII1-8

             SUBSIDIARY COSTS                         VIII-11

             COST ESTIMATES FOR INDIVIDUAL TREATMENT
              TECHNOLOGIES                            VIII-14


             SYSTEM COST ESTIMATES (OPTION 1)         VIII-57

             SYSTEM COST ESTIMATES (OPTION 2)         VIII-61

             SYSTEM COST ESTIMATES (OPTION 3)         VIII-61

             ENERGY AND NON-WATER QUALITY ASPECTS     VII1-81

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                  TABLE OF CONTENTS  (CON'T)

                 Title                                Page

        BEST PRACTICABLE CONTROL TECHNOLOGY
         CURRENTLY AVAILABLE,  GUIDELINES AND         IX-1
         LIMITATIONS

        BEST AVAILABLE TECHNOLOGY ECONOMICALLY         ,
        ACHIEVABLE, GUIDELINES AND LIMITATIONS

  XI    NEW SOURCE PERFORMANCE STANDARDS             XI-1

 XII    PRETREATMENT                                  XII-1

XIII    ACKNOWLEDGEMENTS                              XIII-1

 XIV    REFERENCES                                    XIV-1

  XV    GLOSSARY                                      XV-1

 XVI    APPENDIXES                                    XVI

             APPENDIX A                               A-l

             APPENDIX B                               B-l

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                           LIST OF FIGURES

NUMBER                        TITLE                         PAGE

3-1            Metal Finishing Process Application          Ill-IB
4-1            Waste Effluent Schematic                     IV-9
5-1            Flow Ranges Within The Metal Finishing
               Category                                     V-7
5-2            Waste Effluent Schematic                     V-40
7-1            Waste Treatment Schematic                    VII-2
7-2            Treatment of Common Metals Wastes-Option 1   VII-9
7-3            Precipitation and Sedimentation              VII-11
7-4            Solubilities of Metal Hydroxides as a
               Function of pH                               VII-13
7-5            Representative Types of Sedimentation        VII-15
7-6            Treatment of Common Metals-Option 1          VII-21
7-7            Clarifier TSS Distribution                   VII-22
7-8            Effluent TSS Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-25
7-9            Effluent Cadmium Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-26
7-10           Effluent Chromium Concentrations vs Raw
               Waste Concentrations-Option 1                VII-27
7-11           Effluent Copper Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-28
7-12           Effluent Iron Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-29
7-13           Effluent Lead Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-30
7-14           Effluent Nickel Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-31
7-15           Effluent Zinc Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-32
7-16           Effluent Fluorides Concentrations vs Raw
               Waste Concentrations-Option 1                VII-33
7-17           DCP Data for Effluent TSS Concentration
               Distribution-Option 1                        VII-36
7-18           DCP Data for Effluent Cadmium Concentration
               Distribution-Option 1                        VII-37
7-19           DCP Data for Effluent Chromium Concentration
               Distribution-Option 1                        VII-38
7-20           DCP Data for Effluent Copper Concentration
               Distribution-Option 1                        VII-39
7-21           DCP Data for Effluent Iron Concentration
               Distribution-Option 1                        VII-40
7-22           DCP Data for Effluent Lead Concentration
               Distribution-Option 1                        VII-41
7-23           DCP Data for Effluent Nickel Concentration
               Distribution-Option 1                        VII-42
7-24           DCP Data for Effluent Zinc Concentration
               Distribution-Option 1                        VII-43
                            Mil

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                     LIST OF FIGURES (CONTINUED)


NUMBER                        TITLE                         PAGE

7-25           DCP Data for Effluent Fluorides Concentra-
               tion Distribution-Option 1                   VII-44
7-26           Effluent TSS Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-45
7-27           Effluent Cadmium Concentrations vs Raw
               Waste Concentrations-Option 1                VII-46
7-28           Effluent Chromium Concentrations vs Raw
               Waste Concentrations-Option 1                VII-47
7-29           Effluent Copper Concentrations vs Raw
               Waste Concentrations-Option 1                VII-48
7-30           Effluent Iron Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-49
7-31           Effluent Lead Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-50
7-32           Effluent Nickel Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-51
7-33           Effluent Zinc Concentrations vs Raw Waste
               Concentrations-Option 1                      VII-52
7-34           Effluent Fluorides Concentrations vs Raw
               Waste Concentrations-Option 1                VII-53
7-35           Treatment of Common Metals-Option 2          VII-55
7-36           Granular Bed Filtration Example              VII-59
7-37           Effluent TSS Concentrations vs Raw Waste
               Concentrations-Option 2                      VII-64
7-38           Effluent Cadmium Concentrations vs Raw
               Waste Concentrations-Option 2                VII-65
7-39           Effluent Chromium Concentrations vs Raw
               Waste Concentrations-Option 2                VII-66
7-40           Effluent Copper Concentrations vs Raw Waste
               Concentrations-Option 2                      VII-67
7-41           Effluent Iron Concentrations vs Raw Waste
               Concentrations-Option 2                      VII-68
7-42           Effluent Lead Concentrations vs Raw Waste
               Concentrations-Option 2                      VII-69
7-43           Effluent Nickel Concentrations vs Raw Waste
               Concentrations-Option 2                      VII-70
7-44           Effluent sine concentrations vs Raw Waste
               Concentrations-Option 2                      VII-71
7-45           Effluent Fluorides Concentrations vs Raw
               Waste Concentrations-Option 2                VII-72
7-46           DCP Data For Effluent TSS Concentration
               Distribution-Option 2                        VII-73
7-47           DCP Data For Effluent Cadmium Concentration
               Distribution-Option 2                        VII-74
7-48           DCP Data For Effluent Chromium Concentration
               Distribution-Option 2                        VII-75
                              IX

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                     LIST OF FIGURES (CONTINUED)


NUMBER                        TITLE                         PAGE

7-49           DCP Data For Effluent Copper Concentration
               Distribution-Option 2                        VII-76
7-50           DCP Data For Effluent Iron Concentration
               Distribution-Option 2                        VII-77
7-51           DCP Data For Effluent Lead Concentration
               Distribution-Option 2                        VII-78
7-52           DCP Data For Effluent Nickel Concentration
               Distribution-Option 2                        VII-79
7-53           DCP Data For Effluent Zinc Concentration
               Distribution-Option 2                        VII-80
7-54           DCP Data For Effluent Fluorides Concentration
               Distribution-Option 2                        VII-81
7-55           Types of Evaporation Equipment               VII-84
7-56           Ion Exchange With Regeneration               VII-89
7-57           Extended Surface Electrolysis Cells          VII-98
7-58           Application of Extended Surface Electrolysis VII-99
7-59           Effect of Concentration on Electrical
               Efficiency In Metals Reduction               VII-100
7-60           Simple Electrodialysis Cell                  VII-102
7-61           Mechanism of the Electrodialytic Process     VII-104
7-62           Electrodialysis Recovery System              VII-106
7-63           Simplified Reverse Osmosis Schematic         VII-107
7-64           Reverse Osmosis Membrane Configurations      VII-108
7-65           Comparative Soluabilities of Metal and
               Sulfides As A Function Of pH                 VII-116
7-66           Dissolved Air Flotation                      VII-120
7-67           Observed Evaporation System At Plant ID
               06090                                        VII-127
7-68           Effluent Silver Concentrations vs Raw Waste
               Concentrations-Option 1 Treatment System     VII-129
7-69           Effluent Silver Concentrations vs Raw Waste
               Concentrations-Option L Common Metals        VII-130
7-70           DCP Data For Effluent Silver Concentration
               Distribution                                 VII-131
7-71           Hexavalent Chromium Reduction With Sulfur
               Dioxide                                      VII-136
7-72           Effluent Hexavalent Chromium Concentrations
               vs Raw Waste Concentrations                  VII-139
7-73           DCP Data For Effluent Hexavalent Chromium
               Concentration Distribution                   VII-140
7-74           Electrolytic Recovery                        VII-145
7-75           Treatment Of Cyanide Waste By Alkaline
               Chlorination                                 VII-149
7-76           Percentile Distribution Of Total Cyanide
               Effluent Concentration                       VII-153
7-77           DCP Data For Effluent Total Cyanide Con-
               centration Distribution                      VII-154
7-78           DCP Data For Effluent Amenable Cyanide
               Concentration Distribution                   VII-155

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                     LIST OF FIGURES (CONTINUED)


NUMBER                        TITLE                         PAGE

7-79           Typical Ozone Plant For Waste Treatment      VII-157
7-80           UV/Ozonation                                 VII-162
7-81           Effluent Oil And Grease Concentrations vs
               Raw Waste Concentrations-Option 1 Common
               Metals                                       VII-170
7-82           Effluent Oil and Grease Concentrations vs
               Raw Waste Concentrations-Option 1 (Entire
               Metal Finishing Category Data Base)           VII-171
7-83           DCP Data For Effluent Oil And Grease
               Concentration Distribution                   VII-172
7-84           Effluent Oil And Grease Concentrations vs
               Raw Waste Concentrations For Option 2 Data
               Base  (Combined Wastewater)                   VII-173
7-85           DCP Data For Oil And Grease Effluent
               Distribution-Option 2                        VII-175
7-86           Percentile Distribution Of Total Toxic
               Organics In Common Metals Wastewaters        VII-176
7-87           Treatment Of Segregated Oily Wastes-Option 1 VII-179
7-88           Typical Emulsion Breaking/Skimming System    VII-181
7-89           Segregated Oil And Grease Effluent Per-
               formance-Option 1                            VII-187
7-90           Segregated Oil And Grease Effluent Concen-
               tration vs Raw Waste-Option 1                VII-189
7-91           Percentile Distribution Of Total Priority
               Organics In Segregated Oily Wastewaters      VII-190
7-92           Treatment Of Segregated Oily Wastes-Option 2 VII-192
7-93           Simplified Ultrafiltration Flow Schematic    VII-194
7-94           Treatment Of Segregated Oily Wastes-Option 3 VII-199
7-95           Activated Carbon Adsorption Column           VII-203
7-96           Coalescing Gravity Separator                 VII-212
7-97           Typical Dissolved Air Flotation System       VII-215
7=98           Schematic Diagram Of A Conventional Activated
               Sludge System                                VII-222
7-99           Schematic Cross Section Of A Trickling
               Filter                                       VII-223
7-100          Schematic Diagram of A Single-stage Trickling
               Filter                                       VII-224
7-101          Thermal Emulsion Breaker                     VII-227
7-102          Alkaline Wash Oil Separator                  VII-235
7-103          Mechanical Gravity Thickening                VII-239
7-104          Pressure Filtration                          VII-242
7-105          Vacuum Filtration                            VII-245
7-106          Centrifugation                               VII-249

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                     LIST OF FIGURES (CONTINUED)
NUMBER

8-1

8-2
8-3
8-4

8-5
8-6

8-7
8-8
8-9

8-10
8-11
8-12
8-13
8-14
8-15
8-16

8-17
8-18
8-19

8-20

8-21

8-22
8-23

8-24

8-25
8-26

8-27
8-28

8-29

8-30

8-31
               TITLE                         PAGE

Simplified Logic Diagram-System Cost
Estimation Program                           VIII-5
Simple Waste Treatment System                VIII-7
Cyanide Oxidation Investment Cost            VIII-17
Chemical Oxidation Of Cyanide Annual Labor
Required                                     VIII-19
Cyanide Oxidation Chemical And Energy Cost   VIII-21
Chemical Reduction Of Chromium Investment
Cost                                         VIII-23
Chromium Reduction Annual Labor              VIII-24
Clarifier Investment Cost                    VIII-26
Lime Precipitation/Clarification Continuous
Treatment Labor Required                     VIII-28
Holding Tanks Investment Cost                VIII-32
Holding Tanks Energy Cost                    VIII-33
Holding Tank Labor Requirements              VIII-34
Chemical Emulsion Breaking Investment Cost   VIII-36
Chemical Emulsion Breaking Labor Required    VIII-37
Multimedia Filter Investment Costs           VIII-39
Multimedia Filter Operation and Maintenance
Cost                                         VIII-
Ultrafiltration Investment Cost              VIII-41
Ultrafiltration Labor Required               VIII-42
Carbon Adsorption Investment Cost (Throwaway
type)                                        VIII-43
Carbon Adsorption Labor Required (Throwaway
type)                                        VIII-44
Carbon Adsorption Electricity Usage (Throw-
away type)                                   VI11-45
Sludge Drying Bed Investment Cost            VIII-48
Sludge Drying Bed Labor Required For
Operation                                    VIII-49
Sludge Drying Bed Labor Required For
Maintenance                                  VIII-50
Sludge Drying Bed Annual Material Cost       VIII-51
Submerged Tube (Double Effect) Evaporator
Investment Cost                              VIII-55
Option 1 System                              VIII-58
Total Annual Cost vs Flow Rate For Option 1
Treatment System, Case 1                     VIII-62
Total Annual Cost vs Flow Rate For Option 1
Treatment System, Case 2                     VIII-63
Total Annual Cost vs Flow Rate For Option 1
Treatment System, Case 3                     VIII-64
Total Annual Cost vs Flow Rate For Option 1
Treatment System, Case 4                     VIII-65

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                     LIST OF FIGURES (CONTINUED)
NUMBER

8-32

8-33
8-34

8-35

8-36

8-37

8-38

8-39
8-40

8-41

8-42

8-43

8-44
               TITLE

Total Annual Cost vs Flow
Treatment System, Case 5
Option 2 System
Total Annual Cost vs Flow
Treatment System, Case 1
Total Annual Cost vs Flow
Treatment System, Case 2
Total Annual Cost vs Flow
Treatment System, Case 3
Total Annual Cost vs Flow
Treatment System, Case 4
Total Annual Cost vs Flow
Treatment System, Case 5
Option 3 System
Total Annual Cost vs Flow
Treatment System, Case 1
Total Annual Cost vs Flow
Treatment System, Case 2
Total Annual Cost vs Flow
Treatment System, Case 3
Total Annual Cost vs Flow
Treatment System, Case 4
Total Annual Cost vs Flow
Treatment System, Case 5
Rate For Option 1


Rate For Option 2

Rate For Option 2

Rate For Option 2

Rate For Option 2

Rate For Option 2


Rate For Option 3

Rate For Option 3

Rate For Option 3

Rate For Option 3

Rate For Option 3
PAGE


VIII-66
VIII-67

VIII-68

VIII-69

VIII-70

VIII-71

VIII-72
VIII-74

VIII-75

VIII-76

VIII-77

VIII-78

VIII-79

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                         LIST OF TABLES

NUMBER                        TITLE                         PAGE

3-1            Metal Finishing Category Unit Operations     III-6
3-2            Sampling Parameters                          III-ll
3-3            Industries Within The Metal Finishing
               Category                                     111-16
4-1            Waste Characteristic Distribution            IV-7
5-1            Water Usage By Metal Finishing Operations    V-4
5-2            Determination of Zero Discharge Operations   V-5
5-3            Determination of Zero Discharge Operations
               (DCP Data Base)                              V-6
5-4            Common Metals Stream Contribution            V-9
5-5            Precious Metals Stream Contribution          V-10
5-6            Complexed Metals Stream Contribution         V-ll
5-7            Hexavalent Chromium Stream Contribution      V-12
5-8            Cyanide Bearing Stream Contribution          V-13
5-9            Segregated Oily Wastewater Contribution      V-14
5-10           Waste Characteristic Distribution            V-16
5-11           Constituents Of Plating Baths                V-18
5-12           Constituents Of Electroless Plating Baths    V-22
5-13           Constituents Of Immersion Plating Baths      V-24
5-14           Constituents Of Process Baths Used In
               Etching                                      V-29
5-15           Minimum Detectable Limits                    V-41
5-16           Pollutant Concentrations Found In The Common
               Metals Raw Waste Stream                      V-44
5-17           Pollutant Concentrations Found in the
               Precious Metals Raw Waste Stream             V-45
5-18           Pollutant Concentrations Found In The Complex
               Metals Raw Waste Stream                      V-45
5-19           Pollutant Concentrations Found In The
               Hexavalent Chromium Raw Waste Stream         V-45
5-20           Pollutant Concentrations Found In The
               Cyanide Raw Waste Stream                     V-45
5-21           Pollutant Concentrations Found In The Oily
               Raw Waste Stream                             V-46
5-22           Oil Waste Characterization                   V-48
5-23           Solubility Of Toxic Organic Parameters       V-50
5-24           1974 Degreasing Solvent Consumption          V-51
5-25           Summary Of DCP Solvent Degreasing Data       V-53
5-26           Priority Organics Used In Metal Finishing    V-55
6-1            Pollutant Parameter Questionnaire—DCP
               Responses                                    VI-2
6-2            Pesticide-type Priority Pollutants Not
               Selected For Regulation                      VI-9
6-3            Common Metals Subcategory—Toxic Organics
               Which Occur At A Concentration Greater
               Than 0.1 mg/1                                VI-10
                            sin

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                     LIST OF TABLES (CON'T)

NUMBER                        TITLE                         PAGE

6-4            Oily Waste Subcategory—Toxic Organics Which
               Occur At A Concentration Greater Than
               0.1 mg/1                                     VI-11
6-5            Raw Waste Concentrations Of Toxic Metals     Vl-13
6-6            Raw Waste Concentrations Of Non-Toxic Metals Vl-14
6-7            Common Metals Subcategory—Selected
               Pollutant Parameters                         VI-16
6-8            Precious Metals Subcategory—Selected
               Pollutant Parameters                         VI-16
6-9            Complexed Metals Subcategory—Selected
               Pollutant Parameters                         VI-17
6-10           Hexavalent Chromium Subcategory—Selected
               Pollutant Parameters                         VI-17
6-11           Cyanide Subcategory—Selected Pollutant
               Parameters                                   VI-17
6-12           Oils Subcategory—Selected Pollutant
               Parameters                                   VI-18
7-1            Index And Specific Application of Treatment
               Technologies                                 VII-5
7-2            Applicability of Treatment Technologies To
               Raw Waste Subcategories                      VII-7
7-3            Metal Finishing Plants With Option 1 Treat-
               ment Systems For Common Metals (Hydroxide
               Precipitation With Sedimentation)            VII-20
7-4            Treatment of Common Metals—Option 1 Mean
               Effluent Concentrations                      VII-34
7-5            Summary Of Daily And 30-Day Average Maximum
               Variability Factors                          VII-34
7-6            Option 1 Common Metals Subcategory Concen-
               trations                                     VII-35
7-7            Percentage of MFC Data Base Below The Daily
               Maximum Concentration Limitation For
               Option 1 (%)                                 VI1-54
7-8            Option 2 Mean Effluent Concentrations        VII-62
7-9            Option 2 Common Metals Subcategory
               Concentrations                               VII-62
7-10           Metal Finishing Plants With Option 2
               Treatment Systems For Common Metals          VII-63
7-11           Percentage of MFC Data Base Below The Daily
               Maximum Concentration Limitation For
               Option 2 (%)                                 Vll-82
7-12           Option 1 And Option 2 Mean Concentration
               Comparison                                   VI1-82
7-13           Option 1 And Option 2 Limitation Comparison  VII-82
7-14           Metal Finishing Plants Employing Evaporation VII-91
7-15           Typical Ion Exchange Performance Data        VIT-92
                               xv

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                     LIST OF TABLES (CON'T)

NUMBER                        T
7-16           Sampling Results From Plant ID 11065         VII-92
7-17           Metal Finishing Plants Employing Ion
               Exchange                                     VII-94
7-18           Metal Finishing Plants Employing Elec-
               trolytic Recovery                            VII-101
7-19           Metal Finishing Plants Employing Reverse
               Osmosis                                      VII-112
7-20           Sampling Data From Sulfide Precipitation/
               Sedimentation Systems                        VII-117
7-21           Metal Finishing Plants Employing Flotation   VII-123
7-22           Metal Finishing Plants Employing Chemical
               Chromium Reduction                           VII-138
7-23           Metal Finishing Plants Employing Cyanide
               Oxidation                                    VII-151
7-24           Oily Waste Removal System Options            VII-168
7-25           Total Toxic Organics Performance- — Common
               Metals Subcategory                           VII-177
7-26           Oils And TTO Limitations — Combined
               Wastewater (Common Metals Subcategory)       VII-177
7-27           Emulsion Breaking Performance Data           VII-183
7-28           Metal Finishing Plants Employing Emulsion
               Breaking                                     VII-184
7-29           Metal Finishing Plants Employing Skimming    VII-186
7-30           Total Toxic Organic Performance — Segregated
               Oily Waste Option 1                          VI 1-188
7-31           Option 1 Limitations — Oily Waste Subcategory VII-191
7-32           Metal Finishing Plants Employing Ultra-
               filtration                                   VII-196
7-33           Ultraf iltration Performance Data For Oil And
               Grease Removal                               VII-197
7-34           Ultraf iltration Performance Data For Total
               Toxic Organics                               VII-197
7-35           Option 1 And Option 2 Performance Limitations
               For Segregated Oil Waste Treatment Systems   VII-198
7-36           Treatability Rating of Priority Pollutants
               Utilizing Carbon Adsorption                  VII-206
7-37           Classes of Organic Compounds Adsorbed On
               Carbon                                       VII-207
7-38           Metal Finishing Plants Employing Carbon
               Adsorption                                   VII-208
7-39           Option 3 Oily Waste Removal Efficiencies     VII-209
7-40           Option 3 Mean Effluent Concentrations        VII-209
7-41           Combined Wastewater — Common Metals
               Subcategory                                  VII-210
7-42           Summary of Effluent Limitation Concentrations
               (mg/1) — Common Metals Subcategory            VII-210

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NUMBER

7-43
7-44

7-45
7-46
7-47

7-48

7-49

7-50

7-51

7-52

7-53

7-54


7-55

8-1
8-2
8-3
8-4
8-5
8-6

8-7

8-8
8-9
8-10
8-11
8-12

8-13
      LIST OF TABLES (CON'T)

               TITLE                         PAGE

Ozone Requirements For Phenol Oxidation      VII-219
Metal Finishing Plants Employing Aerobic De-
composition                                  VII-226
Waste Solvent Contract Haulers               VII-230
Cleaning Approaches                          VII-232
Cleaning Process Relative Ranking (Lowest
Number Is Best)                              VII-234
Comparison of Wastewater At Plant ID 23061
Before And After Dumping of Settling Tank    VII-237
Metal Finishing Plants Employing Gravity/
Sludge Thickening                            VIT-240
Metal Finishing Plants Employing Pressure
Filtration                                   VII-244
Metal Finishing Plants Employing Vacuum
Filtration                                   VII-248
Metal Finishing Plants Employing
Centrifugation                               VII-252
Metal Finishing Plants Employing Sludge
Drying Beds                                  VII-255
Theoretical Rinse Water Flows Required
To Maintain A 1,000 to 1 Concentration
Reduction                                    VII-259
Comparison of Rinse Type Flow Rates For
Sampled Plants                               VII-260
Cost Program Pollutant Parameters            VIII-3
Treatment Technology Subroutines             VIII-9
Wastewater Sampling Frequency                VIII-13
Index To Technology Costs                    VIII-15
Lime Additions For Lime Precipitation        VIII-29
Countercurrent Rinse (For Other Than
Recovery of Evaporative Plating Loss         VIII-54
Countercurrent Rinse Used For Recovery Of
Evaporative Plating Loss                     VIII-54
Flow Split Cases For Options 1, 2, And 3     VIII-59
Option 1 Costs                               VIII-60
Option 2 Costs                               VIII-73
Option 3 Costs                               VIII-80
Non-Water Quality Aspects of Wastewater
Treatment                                    VIII-82
Non-Water Quality Aspects Of Sludge And
Solids Handling                              VIII-83

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      SECTION I
TO BE DELIVERED BY EPA
      1-1

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      SECTION  II
TO BE DELIVERED BY  EPA

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                        SECTION III

                        INTRODUCTION
LEGAL AUTHORITY

This document  is written under authority of Sections 301,
304, 306, 307, 308, and 501 of the Clean Water Act  (the Federal
Water Pollution Control Act Amendments of 1972, 33  USC 1251 et
seq., as amended by the Clean Water Act of 1977, P.L. 92-517)
(the "Act").   The document is also in response to the Settlement
Agreement in Natural Resources Defense Council, Inc. et al
v. Train, 8 ERC 2120 (D.D.C 1976) , modified March 9, 1979.

BACKGROUND

The  Federal Water Pollution Control Act Amendments  of 1972
established a  comprehensive program to "restore and maintain the
chemical, physical, and biological integrity of the Nation's
waters."  Section 101(a).  By July 1, 1977, existing industrial
dischargers were required to achieve "effluent limitations
requiring the  application of the  best practicable control technology
currently available" ("BPT"), Section 301(b)(1)(A); and by July 1,
1983, these dischargers were required to achieve "effluent limita-
tions requiring the application of the best available technology
economically achievable ... which will result  in reasonable
further progress toward the national goal of eliminating the
discharge of all pollutants" ("BAT"), Section  301 (b)(2)(A).  New
industrial direct dischargers were required to comply with Section
306  new source performance standards ("NSPS"), based on best
available demonstrated technology, and new and existing dischargers
to publicly owned treatment works ("POTWs") were subject to
pretreatment standards under Sections 307(b) and (c) of the Act.
While the requirements for direct dischargers  were  to be incor-
porated into National Pollutant Discharge Elimination System
(NPDES) permits issued under Section 402 of the Act, pretreatment
standards were made enforceable directly against dischargers to
POTWs (indirect dischargers).

Although Section 402 (a)(l) of the 1972 Act authorized the setting
of requirements for direct dischargers on a case-by-case basis,
Congress intended that, for the most part, control  requirements
would be based on regulations promulgated by the Administrator of
EPA.  Section  304(b) of the Act required the Administrator to
promulgate regulations providing guidelines for effluent limita-
tions setting  forth the degree of effluent reduction attainable
through the application of BPT and BAT.  Moreover,  Sections 304(c)
and  306 of the Act required promulgation of regulations for NSPS,
and  Sections 304(f), 307(b), and  307(c) required promulgation
of regulations for pretreatment standards.
                              III-l

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In addition to these regulations for designated industry categories,
Section 307(a) of the Act required the Administrator to promulgate
effluent standards applicable to all dischargers of toxic pollu-
tants.  Finally, Section 501(a) of the Act authorized the
Administrator to prescribe any additional regulations "necessary
to carry out his functions" under the Act.

The EPA was unable to promulgate many of these regulations by
the dates contained in the Act.  In 1976, EPA was sued by several
environmental groups, and in settlement of this lawsuit EPA and the
plaintiffs executed a "Settlement Agreement" which was approved by
the Court.  This Agreement required EPA to develop a program and
adhere to a schedule for promulgating for 21 major industries BAT
effluent limitations guidelines, pretreatment standards, and new
source performance standards for 65 "priority" pollutants and classes
of pollutants.  See Natural Resources Defense Council, Inc. et al
v. Train, 8 ERG 2120 (D.D.C. 1976), modified March 9, 1979.

On December 27, 1977, the President signed into law the Clean Water
Act of 1977.  Although this law makes several important changes in
the Federal water pollution control program, its most significant
feature is its incorporation into the Act of several of the basic
elements of the Settlement Agreement program for toxic pollution
control.  Sections 301(b)(2)(A) and 301(b)(2)(C) of the Act now
require the achievement by July 1, 1984 of effluent limitations
requiring application of BAT for "toxic" pollutants, including the
65 "priority" pollutants and classes of pollutants which Congress
declared "toxic" under Section 307(a) of the Act.   Likewise, EPA's
programs for new source performance standards and pretreatment
standards are now aimed principally at toxic pollutant controls.
Moreover, to strengthen the toxics control program, Section 304(e)
of the Act authorizes the Administrator to prescribe "best
management practices" ("BMPs") to prevent the release of toxic
and hazardous pollutants from plant site runoff, spillage or
leaks, sludge or waste disposal, and drainage from raw material
storage associated with, or ancillary to, the manufacturing or
treatment process.

In keeping with its emphasis on toxic pollutants,  the Clean Water
Act of 1977 also revises the control program for non-toxic pollutants,
Instead of BAT for "conventional" pollutants identified under
Section 304(a)(4) (including biochemical oxygen demand, suspended
solids, fecal coliform and pH), the new Section 301(b)(2)(F)
requires achievement by July 1, 1984, of "effluent limitations
requiring the application of the best conventional pollutant
control technology" ("BCT").  The factors considered in assessing
BCT for an industry include the costs of attaining a reduction
in effluents and the effluent reduction benefits derived compared
to the costs and effluent reduction benefits from the discharge
of publicly owned treatment works (Section 304(b)(4)(B)).  For
                              III-2

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non-toxic, nonconventional pollutants, Sections 301(b)(2)(A) and
(b)(2)(F) require achievement of BAT effluent limitations within
three years after their establishment or July 1, 1984, whichever
is later, but not later than July 1, 1987.

GUIDELINE DEVELOPMENT SUMMARY

The Metal Finishing Category (MFC) encompasses 44 unit operations
involved in the machining, fabrication and finishing of products
in SIC groups 34 through 39.  The effluent guidelines for the
Metal Finishing Category were developed from data obtained from
previous EPA studies, literature searches, and plant surveys and
evaluations.  Initially, all existing information from EPA records
and data from literature searches were collected.  This information
was then compiled in a format that summarized the individual plant
descriptions for the following  information:  manufacturing unit
operations performed, water usage, process water discharges, waste-
water treatment practices, and  wastewater constituents.

In addition to providing a quantitative description of the
Metal Finishing Category, this  existing information was used to
determine if the wastewater characteristics of the industry as
a whole were uniform and thus amenable to one set of discharge
standards.  Because the discharge characteristics of all plants
in the existing data base were  not uniform, it was necessary
to establish subcategories for  which the wastewater character-
istics of each were uniform.  Subcategorization of this industry
segment was based upon the seven classifications of waste char-
acteristics that are present:

          Common Metals
          Precious Metals
          Complexed Metals
          Hexavalent Chromium
          Cyanide
          Oils
          Solvents

To supplement existing data, data collection portfolios (DCP's)
under the authority of Section  308 of the Federal Water Pollution
Control Act as amended were transmitted by the EPA to a large
number of manufacturing facilities in the Metal Finishing Category-
To supplement the existing data base and the plant supplied in-
formation (via the completed DCP's), a sampling program was
conducted at selected plant locations.  The sampling program
was used to establish the sources and quantities of pollutant
parameters in the raw process wastewater and the treated effluent.
The sites visited were chosen on the basis of either the specific
manufacturing operations performed or the particular waste
treatment technology employed.  All of the data collected were
                               III-3

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analyzed to determine the pollutants generated by the manufacturing
processes for each subcategory.

In addition to evaluating pollutant constituents and discharge
rates, the full range of control and treatment technologies
within the Metal Finishing Category was identified and examined.
This was done considering the pollutants to be treated and their
chemical, physical, and biological characteristics.  Special
attention was paid to in-process technology such as the recovery
and reuse of process solutions, the recycle of process water, and
the reduction of water use.

This information was then evaluated in order to determine the
levels of technology appropriate as bases for effluent limitations
for existing sources after July 1, 1977, ("Best Practicable
Control Technology Currently Available") and after July 1, 1983
("Best Available Technology Economically Achievable").  Levels
of technology appropriate for pretreatment of wastewater dis-
charges to POTW1s from both new and existing sources were also
identified as were the "best demonstrated control technology,
processes, operating methods, or other alternatives" (BDT) for
the control of direct discharges from new sources.  Various
factors were considered in the evaluation of these technologies.
These factors included demonstrated effluent performance of treat-
ment technologies, any pretreatment requirements, the total cost
of application of the technology in relation to the pollution
reduction benefits to be achieved, the production processes
employed, the engineering aspects of the application of various
types of control techniques and process changes, and non-water
quality environmental impact (including energy requirements).

SOURCES OF INDUSTRY DATA

Data for the Metal Finishing Category were gathered from literature
surveys, previous studies of the industry by the EPA, inquiries to
professional contacts, seminar and meeting attendance, and the.
survey and evaluation of manufacturing facilities.

Literature Study

Published literature in the form of books, periodicals, reports,
papers, and promotional materials was examined.  These sources
are listed in Section XIV.  The material researched included
manufacturing processes, recycling/reclamation techniques,
pollutant characteristics, waste treatment technologies and
cost data.
                               III-4

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Previous EPA Studies

Previous EPA studies that contributed technical information
to the Metal Finishing Category data base were:

          Machinery & Mechanical Products Manufacturing
          Category

          Electroplating Category

          Electroless Plating & Printed Circuit Board
          Manufacturing Segments of the Electroplating
          Category

          Printing & Publishing Category

          Mechanical & Electrical Products Category

          Copper & Copper Alloy Manufacturing Category

          Aluminum & Aluminum Alloy Manufacturing Category

          Iron & Steel Manufacturing Category

These EPA studies provided information on the process raw wastes
generated by each of the metal finishing operations listed in
Table 3-1 and the treatment utilized by industry to control the
pollutants in these wastes.  Information from the Machinery &
Mechanical Products Manufacturing Category study was used
specifically to identify plants that had segregated wastes for
particular manufacturing unit operations and employed treatment
to control these wastes.  Applicable plants were selected for
sampling to establish the subcategory waste characteristics and
the performance of existing wastewater treatment components and
systems.  In addition, waste treatment technology transfer was
used from all of the previous EPA studies listed to obtain addi-
tional performance data on existing treatment facilities that
are applicable to the metal finishing industry.
                              III-5

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                         TABLE 3-1
          METAL FINISHING CATEGORY UNIT OPERATIONS
UNIT OPERATIONS
1.   Electroplating
2.   Electroless Plating
3.   Anodizing
4.   Conversion Coating
5.   Etching (Chemical Milling)
6.   Cleaning
7.   Machining
8.   Grinding
9.   Polishing
10.  Tumbling
11.  Burnishing
12.  Impact Deformation
13.  Pressure Deformation
14.  Shearing
15.  Heat Treating
16.  Thermal Cutting
17.  Welding
18.  Brazing
19.  Soldering
20.  Flame Spraying
21.  Sand Blasting
22.  Other Abrasive Jet Machining
23.  Electric Discharge Machining
24.  Electrochemical Machining
25.  Electron Beam Machining
26.  Laser Beam Machining
27.  Plasma Arc Machining
28.  Ultrasonic Machining
29.  Sintering
30.  Laminating
31.  Hot Dip Coating
32.  Sputtering
33.  Vapor Plating
34.  Thermal Infusion
35.  Salt Bath Descaling
36.  Solvent Degreasing
37.  Paint Stripping
38.  Painting
39.  Electrostatic Painting
40.  Electropainting
41.  Vacuum Metalizing
42.  Assembly
43.  Calibration
44.  Testing
                               III-6

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Professional Contacts

All Federal EPA regions and several state environmental agencies
were contacted to obtain permit and monitoring data on plants
that performed metal finishing processes.

Numerous suppliers and manufacturers for the metal finishing
industry were contacted to collect information regarding the
use and properties of materials, constituents of process
chemicals, waste treatment equipment, waste contract haulers,
and possible applications of process modifications to minimize
the generation of pollutants.

Seminars and Meetings

An Advanced Wastewater Treatment Seminar provided methods for
accurately estimating waste treatment costs.  The American Electro-
platers Society Intensive Training Course in Electroplating and
Surface Finishing was taken.  The Eastern Plant Engineering Con-
ference on lubricant management, conservation, recycling, and
disposal was also attended.

In addition, jointly sponsored EPA/American Electroplaters'
Society conferences on Advanced Pollution Control for the
Metal Finishing Industry were attended.  At these conferences
various papers on metal finishing technology and waste treatment
w'ere presented by the industry and the EPA.  A meeting of the
Continuous Coil Anodizing Association was also attended.  The
EPA sponsored an informational meeting with the Association of
Home Appliance Manufacturers, the Electrical Industries of
America, the Motor Vehicles Manufacturers Association of the
United States, the National Association of Manufacturers, and
the National Electrical Manufacturers Association.

Plant Survey and Evaluation

The collection of data pertaining to facilities in the metal
finishing industry was accomplished via two primary mechanisms.
The EPA conducted a survey wherein data collection portfolios
(DCPs) in questionnaire form were mailed to production facili-
ties.  Also, a plant visit and sampling program was implemented
to accumulate the specific data necessary for each waste charac-
teristic subcategory-

Data Collection Portfolios - Data collection portfolios of three
types were sent to various industries within the Metal Finishing
Category-  All three DCP forms are presented in Appendix A.  The
first DCP was  utilized during the Machinery and Mechanical
Products Industries Study.  Data were obtained from 339 production
facilities that were selected from a group of 1,422 plants originally
                               III-7

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contacted by telephone.  Requested information included general
plant data, principal raw materials consumed, specific produc-
tion processes employed, composition of effluent streams and
wastewater treatment in use.

The second DCP, used during the M&EP study was sent to 900 facilities
that were randomly selected from approximately 160,000 manufacturers
listed in recent Dun & Bradstreet data.  This DCP requested informa-
tion pertinent to general plant characteristics, unit operations
performed (including quantity, frequency, and method of liquid dis-
posal), data related specifically to plating type operations,
wastewater treatment facilities, and the contract hauling of wastes.
A total of 365 useful responses resulted from the mailing of this
questionnaire.

The third DCP, was used during the Electroplating study.  It was
mailed to 1883 companies believed to operate plating facilities.
This mailing list was randomly selected from among the approxi-
mately 13,000 facilities that perform plating in the United
States.  There were approximately 970 complete responses (from
419 companies) to this questionnaire mailing.  This survey re-
quested information regarding general plant characteristics, pro-
duction history, manufacturing processes, process and waste treat-
ment, wastewater characteristics, treatment costs, and economic
analysis data.

Plant Sampling Visits - During the study of the metal finishing
industry, a total of 198 manufacturing facilities were visited.
The criteria used to select plants for sampling visits were:

1.   A large percentage of the plant's effluent discharge should
     result from the manufacturing processes listed in Table 3-1.

2.   The physical layout of plant plumbing should facilitate
     segregation of the wastewater subcategory under study.

3.   The plant must have adequate waste treatment control
     technology in place.

4.   The mix of plants visited should contain dischargers to
     both surface waters and publicly owned treatment works
     (POTW).
                              III-8

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5.   The selected plants should provide a representative
     geographical distribution to avoid a data base that
     concentrates on a unique geographical condition.

The plant visits consisted of two major activities:  collection
of all pertinent technical information related to both the
manufacturing processes and the treatment techniques and collec-
tion of wastewater samples.  The technical data gathering effort
entailed completion of the applicable data collection portfolio
and obtaining information in the following specific areas:

1.   Rinsing operations and their effect on water use and waste
     characteristics.

2.   Water conservation techniques, both practiced and planned.

3.   Overall performance of the waste treatment system and
     future plans or changes anticipated.

4.   Current effluent limitations under which the plant is
     operating and any difficulties in meeting them.

5.   Process modifications which significantly alter the
     characteristics of the wastewater generated.

6.   Particular pollution parameters which plant personnel
     believe will be found in the waste stream.

7.   Any problem or situation peculiar to the plant being
     visited.

The object of plant sampling was to determine by analysis which
pollutants were present in the plant wastewater for each sub-
category-  The wastewater collection at the visited plants con-
sisted of a composite sampling program performed over a two or
three day period.  Prior to the sampling visit, all available
data pertaining to manufacturing processes and waste treatment
were reviewed.  Representative sample points were selected for
the raw wastewater entering the treatment systems and for the
final treated effluents.  Finally a detailed sampling plan
showing the selected sample points and the overall sampling
procedure was prepared, reviewed, and approved by the EPA.
The format of this sampling plan is shown in Appendix B.
                               III-9

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Composite samples (24 hour composites) were taken at each sample
point for two or three consecutive days.  The plants which were
sampled were divided into two sample analysis groups.  Within
each analysis group the samples were subjected to various levels
of analysis depending on the stability of the parameters to be
analyzed.  These analysis groups and the various levels of
analysis within were:

1.   On-site analysis, local laboratory analysis, Chicago EPA
     laboratory analysis, GC/MS laboratory analysis, and
     central laboratory analysis.

2.   On-site analysis, local laboratory analysis, EPA contracted
     laboratory metals analysis and EPA contracted laboratory
     organics analysis.

In the first analysis group, on-site analysis performed by the
sampler at the facility determined flow rate, pH, and temperature.
Several liters of water from each sample point were delivered to
a laboratory in the locality of the subject plant and analyzed
for total cyanide, cyanide amenable to chlorination, TSS, oil
and grease, and phenols.  This analysis was performed by local
laboratories within a 24 hour period after the composite sample
was prepared. Two liters of water from each sample point were
sent to an EPA laboratory where .screening analysis was run to
establish metals present in the samples.  Water samples
from each point were also sent to a laboratory with GC/MS capa-
bilities to determine organics that were present.  The remainder
of the wastewater was shipped to a central laboratory where
analysis was performed to verify the levels of metals, organics,
and total dissolved solids as appropriate.  For some sampling
visits the Chicago EPA laboratory and the GC/MS laboratory were
eliminated.  Analysis for certain special parameters such as
palladium and rhodium was performed only if the facility being
sampled utilized such materials in their process lines.  Samples
from electroless plating plants were also analyzed for the
complexing agents which were being used by the plants.  In
addition to this sampling and analysis, special grab samples
were collected from certain plants to obtain data related to
specific unit operations, process variations, or rinsing opera-
tions.   In the second analysis group, the on-site analysis
remained the same as in the first group.  The local laboratory
analyzed for total cyanide, oil and grease, ammonia nitrogen,
TOC, TSS, BOD, and phenols.  These were analyzed within 24 hours
after the composite sample was prepared.  Two liters of water
were sent to an EPA contracted laboratory to perform analysis to
determine metals present in the water samples.  Additional water
was sent to a second EPA contracted laboratory for analysis to
determine organics present in the wastewater.

The acquisition, preservation, and analysis of the water samples
were performed in accordance with methods set forth in 40 CFR Part
136.  An example of a wastewater analysis report used for each
facility visited, showing a data checklist and on-site local and
central laborataroy analysis results, is presented in Appendix B.
Sampling parameters are presented in Table 3-2.
                              111-10

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                Table 3-2

          SAMPLING PARAMETERS
 1  acenaphthene
 2  acrolein
 3  acrylonitrile
 4  benzene
 5  benzidine
 6  carbon tetrachloride (tetrachloromethane)
 7  chlorobenzene
 8  1,2,4-trichlorobenzene
 9  hexachlorobenzene
10  1,2-dichloroethane
11  1,1,1-trichloroethane
12  hexachloroethane
13  1,1-dichloroethane
14  1/1,2-trichloroethane
15  1,1,2,2-tetrachloroethane
16  chloroethane
17  bis(chloromethyl) ether
18  bis(2-chloroethyl) ether
19  2-chloroethyl vinyl ether (mixed)
20  2-chloronaphthalene
21  2,4,6-trichlorophenol
22  parachlorometa cresol
23  chloroform (trichloromethane)
24  2-chlorophenol
25  1,2-dichlorobenzene
26  1,3-dichlorobenzene
27  1,4-dichlorobenzene
28  3,3'-dichlorobenzidine
29  1,1-dichloroethylene
30  1,2-trans-dichloroethylene
31  2,4-dichlorophenol
32  1,2-dichloropropane
33  1,2-dichloropropylene (1,3-dichloropropene)
34  2r4-dimethylphenol
35  2,4-dinitrotoluene
36  2,6-dinitrotoluene
37  1,2-diphenylhydrazine
38  ethylbenzene
39  fluoranthene
40  4-chlorophenyl phenyl ether
41  4-bromophenyl phenyl ether
42  bis(2-chloroisopropyl)  ether
43  bis(2-chloroethoxy) methane
44  methylene chloride (dichloromethane)
45  methyl chloride (chloromethane)
                    III-ll

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           Table 3-2  (CONT.)
          SAMPLING PARAMETERS
46  methyl bromide (bromomethane)
47  bromoform (tribromomethane)
48  dichlorobromomethane
49  trichlorofluoromethane
50  dichlorodifluoromethane
51  chlorodibromomethane
52  hexachlorobutadiene
53  hexachlorocyclopentadiene
54  isophorone
55  naphthalene
56  nitrobenzene
57  2-nitrophenol
58  4-nitrophenol
59  2,4-dinitrophenol
60  4,6-dinitro-o-cresol
61  N-nitrosodimethylamine
62  N-nitrosodiphenylamine
63  N-nitrosodi-n-propylamine
64  pentachlorophenol
65  phenol
66  bis(2-ethylhexyl) phthalate
67  butyl benzyl phthalate
68  di-n-butyl phthalate
69  di-n-octyl phthalate
70  diethyl phthalate
71  dimethyl phthalate
72  1,2-benzanthracene (benzo(a)anthracene)
73  benzo (a) pyrene (3,4-benzo-pyrene)
74  3,4-benzofluoranthene (benzo(b)fluoranthene )
75  11,12-benzofluoranthene (benzo(k)fluoranthene)
76  chrysene
77  acenaphthylene
78  anthracene
79  1,12-benzoperylene (benzo(ghi)-perylene)
80  fluorene
81  phenanthrene
82  1,2,5f6-dibenzanthracene (dibenzo (a,h)  anthracene)
83  indeno (1,2,3-cd) pyrene (2,3-o-phenylene pyrene)
84  pyrene
85  tetrachloroethylene
86  toluene
87  trichloroethylene
88  vinyl chloride (chloroethylene)
89  aldrin
90  dieldrin
91  chlordane (technical mixture and metabolites)
                    111-12

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          TABLE 3-2
     SAMPLING PARAMETERS
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
119
120
121
122
123
124
125
126
127
128
129
4, 4 '-DDE (p,p'-DDX)
4, 4 '-ODD (p,p'-TDE)
alpha-endosulfan
beta-endosulf an
endosulfan sulfate
endrin
endrin aldehyde
heptachlor








heptachlor epoxide (BHC=hexachlorocyclohexane)
alpha-BHC
beta-BHC
gamma-BHC (lindane)



delta-BHC (PCB-polychlorinated biphenyls)
PCB-1242 (Arochlor 1242)
PCB-1254 (Arochlor 1254)
PCB-1221 (Arochlor 1221)
PCB-1232 (Arochlor 1232)
PCB-1248 (Arochlor 1248)
PCB-1260 (Arochlor 1260)
PCB-1016 (Arochlor 1016)
toxaphene
antimony
arsenic
asbestos
beryllium
cadmium
chromium, total
chromium, hexavalent
copper
















cyanide, total & amenable to chlorination
lead
mercury
nickel
selenium
silver
thallium
zinc
2,3,7, 8-tetrachlorodibenzo-p-dioxin







(TCDD)
xylenes
alkyl epoxides
gold
fluoride
phosphorus
oil & grease
TSS
pH
               111-13

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      Table 3-2   (CONT.)
     SAMPLING PARAMETERS
aluminum
barium
iridium
magnesium
molybdenum
osmium
palladium
platinum
rhodium
ruthenium
sodium
tin
titanium
vanadium
yttrium
total phenols
flow
total suspended solids
               111-14

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UTILIZATION OF INDUSTRY DATA

Data collected from the previously described sources are used
throughout this report in the development of a basis for limit-
ation options.  Subcategorization based upon the seven distinct
types of process raw waste characteristics that occur in the
Metal Finishing Category is presented in Section IV.  These
seven process raw waste subcategories are: common metals, precious
metals, complexed metals, hexavalent chromium, cyanide, oils, and
solvents.  The water usage and raw waste characteristics for each
subcategory, presented in Section V, were obtained from the analy-
sis of raw wastewater samples taken from the process wastes dis-
charged by the manufacturing unit operations.  Selection of the
pollutant parameters for control  (Section VI) was made from these
plant sampling results.  This selection required that two criteria
be met:  first, the pollutant nature of the parameter must be
significant; and second, it must be discharged at a significant
concentration level.  Based on the amount and types of pollutants
requiring control, applicable treatment technologies were studied
and are discussed in Section VII of this document.  Wastewater
treatment technologies utilized by the Metal Finishing Category
plants and observed during plant visits were used to identify
applicable treatment technologies.  All performance data presented
are for existing treatment installations.  Both in-process control
and end-of-pipe wastewater treatment were studied and are included
in the discussion.  Actual sampling data performance is used in
Section VII to define treatment system performance and for the
presentation of actual achievable effluent concentration levels
for various treatment options for each metal finishing subcategory.
The cost of treatment (for both individual technologies and systems)
based on literature surveys, on-site surveys, and data from equip-
ment manufacturers is contained in Section VIII of this document.

INDUSTRY DESCRIPTION

The industries covered by the Metal Finishing Category are
included in Standard Industrial Classification (SIC) Major Groups
34 through 39 and are those that perform some combination of the
44 manufacturing unit operations listed in Table 3-1.

The specific industries covered by these Major Groups are listed  in
Table 3-3.  Industries not covered by this document include porcelain
enameling, coil coating, batteries manufacturing, electrical and
electronic components, photographic equipment and supplies, iron  and
steel, aluminum and aluminum alloys, copper and copper alloys, and
shipbuilding.  These industries have been specifically excluded
from this document and have been studied separately.  The industries
listed in Table 3-3 are not exclusively into the Metal Finishing
Category.  For example, all of the industries listed under Major
Group 36 are covered under both the Electrical and Electronics
Component Category and the Metal Finishing Category.  The Electrical
and Electronic Components Category covers all processes specific  to
                             111-15

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                                    TABLE 3-3
                 INDUSTRIES WITHIN THE METAL FINISHING CATEGORY

Major Group 34 Fabricated Metal Products, Except Machinery and Transportation Equipment

     341  Metal Cans and Shipping Containers.
     342  Cutlery, Hand Tools, and General Hardware.
     343  Heating Equipment (except Electric and Warm Air, Plumbing Fixtures).
     344  Fabricated Structural Metal Products.
     345  Screw Machine Products, and Bolts, Nuts, Screws, Rivets and Washers.
     346  Metal Forgings and Stampings.
     347  Coating, Engraving and Allied Services.
     348  Ordnance and Accessories, except Vehicles and Guided Missiles.
     349  Miscellaneous Fabricated Metal Products.

Major Group 35 Machinery, Except Electrical

     351  Engines and Turbines.
     352  Farm and Garden Machinery and Equipment.
     353  Construction, Mining and Materials Handling Machinery and Equipment.
     354  Metalworking Machinery and Equipment.
     355  Special Industry Machinery, except Metalworking Machinery.
     356  General Industrial Machinery and Equipment.
     357  Office, Computing, and Accounting Machines.
     358  Refrigeration and Service Industry Machinery.
     359  Miscellaneous Machinery, except Electrical.

Major Group 36 Electrical and Electronic Machinery, Equipment and Supplies

     361  Electric Transmission and Distribution Equipment.
     362  Electrical Industrial Apparatus.
     363  Household Appliances.
     364  Electric Lighting and Wiring Equipment.
     365  Radio and Television Receiving Equipment, except Communication Types.
     366  Communication Equipment.
     367  Electronic Components and Accessories.
     369  Miscellaneous Electrical Machinery, Equipment, and Supplies.

Major Group 37 Transportration Equipment

     371  Motor Vehicles and Motor Vehicle Equipment.
     372  Aircraft and Parts.

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                                     TABLE 3-3  (Cont.)

Major Group 37 Transportation Equipment  (Cont.)

     373  Ship and Boat Building and Repairing.
     374  Railroad Equipment.
     375  Motorcycles, Bicycles, and Parts.
     376  Guided Missiles and Space Vehicles and Parts.
     379  Miscellaneous Transportation Equipment.

Major Group 38 Measuring, Analyzing and  Controlling  Instruments; Photographic, Medical  and
                                     Optical Goods;  Watches and Clocks

     381  Engineering, Laboratory, Scientific,  and Research Instruments and Associated  Equipment,
     382  Measuring and Controlling Instruments.
     383  Optical  Instruments and Lenses.
     384  Surgical, Medical, and Dental  Instruments  and Supplies.
     385  Opthalmic Goods.
     386  Photographic Equipment and Supplies.
     387  Watches, Clocks,  Clockwork Operated Devices, and Parts.

Major Group 39 Miscellaneous Manufacturing Industries

     391  Jewelry, Silverware,  and Plated Ware.
     393  Musical  Instruments.
     394  Dolls.
     395  Pens, Pencils, and Other Office and Artists' Materials.
     396  Costume  Jewelry,  Costume Novelties, Buttons and Miscellaneous Notions, Except
                                     Precious Metal.
     399  Miscellaneous Manufacturing  Industries.

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             COMPLEX PRODUCT
l
i—'
oo
                                              Pressure

                                            Deformation
                                                                                                                                Ship
             SIMPLE PRODUCT
Raw
Stock


Machining
                                                                Ship
                                                                      FIGURE  3-1
                                                        METAL FINISHING PROCESS  APPLICATION

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electronics, and the Metal Finishing Category covers all of the
remaining processes used to manufacture the products in Major
Group 36.

Based upon reviews of recent Dun and Bradstreet data, there
are approximately 160,000 manufacturing facilities in the
United States which are covered by the Metal Finishing Category.
These plants are engaged in the manufacturing of a variety of
products that are constructed primarily by using metals.  The
operations performed (Table 3-1) usually begin with materials  in
the form of raw stock (rods, bars, sheet, castings, forgings,  etc.)
and can progress to the most sophisticated surface finishing opera-
tions.  These facilities vary greatly in size, age, number of
employees and number and type of operations performed.  They range
from very small job shops with less than 10 employees to large
facilities employing thousand of production workers.  Because  of
the differences in size and processes, production facilities are
custom-tailored to the specific needs of each individual plant.
Figure 3-1 illustrates the variation in number of unit operations
that can be performed depending upon the complexity of the product.
The possible variations of unit operation within the Metal Finishing
Category are extensive.  The unit operations (and their sequence)
presented in Figure 3-1 are not actual plants but are representa-
tive of possible manufacturers within the Metal Finishing Category.
Some complex products could require the use of nearly all 44 unit
operations, while a simple product might require only a single
operation.

Many different raw materials are used by the plants in the
Metal Finishing Category-  Basis materials are almost exclusive-
ly metals which range from common copper and steel to extreme-
ly expensive high grade alloys and precious metals.  The
solutions utilized in the various unit operations can contain
acids, bases, cyanide, metals, complexing agents, organic
additives, oils and detergents.  All of these raw materials can
potentially enter wastewater streams during the production sequence.

Water usage within the Metal Finishing Category, the processes that
utilize water and the quantities of process wastewater generated by
metal finishing are presented in Section V.  Plating and cleaning
operations are typically the biggest water users.  While the
majority of metal finishing operations use water, some of them are
completely dry.  The type of rinsing utilized can have a marked
effect on water usage as can the flow rates within the particular
rinse types.  Product quality requirements often dictate the
amount of rinsing needed for specific parts.  Parts requiring  exten-
sive surface preparation will generally necessitate the use of larger
amounts of water.
                              111-19

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The pollutants present in the process raw wastewater and their
concentration ranges are presented in Tables 5-16 through 5-21
by waste characteristic subcategory.  Complete information con-
cerning both water usage and raw wastes are presented in detail
in Section V. There are many treatment components and systems
which are specifically designed to treat the types of wastes
found in metal finishing.  Typical treatment systems and their^
performance are presented in Section VII of this report.  Section
VIII presents the estimated costs of these systems and their
individual components.

UNIT OPERATIONS DESCRIPTIONS

This subsection describes each of the 44 individual unit opera-
tions that are included in the Metal Finishing Category.

     1.   Electroplating is the production of a thin surface
          coating of one metal upon another by electrodeposition.
          This surface coating is applied to provide corrosion
          protection, wear or erosion resistance, anti-frictional
          characteristics, or for decorative purposes.  The electro-
          plating of common metals includes the processes in which
          ferrous or nonferrous basis material is electroplated with
          copper, nickel, chromium, brass, bronze, zinc, tin, lead,
          cadmium, iron, aluminum or combinations thereof.  Precious
          metals electroplating includes the processes in which a
          ferrous or nonferrous basis material is plated with gold,
          silver, palladium, platinum, rhodium, indium, ruthenium,
          iridium, osmium, or combinations thereof.

          In electroplating, metal ions in either acid, alkaline or
          neutral solutions are reduced on cathodic surfaces.  The
          cathodic surfaces are the workpieces being plated.  The
          metal ions in solution are usually replenished by the
          dissolution of metal from anodes or small pieces con-
          tained in inert wire or metal baskets.  Replenishment
          with metal salts is also practiced, especially for
          chromium plating.  In this case, an inert material must
          be selected for the anodes.  Hundreds of different
          electroplating solutions have been adopted commercially
          but only two or three types are utilized widely for a
          particular metal or alloy.  For example, cyanide
          solutions are popular for copper, zinc, brass, cadmium,
          silver, and gold.  However, non-cyanide alkaline solu-
          tions containing pyrophosphate have come into use
          recently for zinc and copper.  Zinc, copper, tin and
          nickel are plated with acid sulfate solutions, expecially
          for plating relatively simple shapes.  Cadmium and zinc
                              111-20

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     are sometimes electroplated from neutral or slightly aci-
     dic chloride solutions.  The most common methods of plating
     are in barrels, on racks, and continuously from a spool or
     coil.

2«   Electroless Plating is a chemical reduction process which
     depends upon the catalytic reduction of a metallic ion
     in an aqueous solution containing a reducing agent and
     the subsequent deposition of metal without the use of
     external electrical energy.  It has found widespread use
     in industry due to several unique advantages over con-
     ventional electroplating.  Electroless plating provides a
     uniform plating thickness on all areas of the part
     regardless of the configuration or geometry of the part.
     An electroless plate on a properly prepared surface is
     dense and virtually non-porous.  Copper and nickel
     electroless plating are the most common.  The basic
     ingredients in an electroless plating solution are:

          1.   A source of metal, usually a salt.
          2.   A reducer to reduce the metal to its base state.
          3.   A complexing agent to hold the metal in solution
               (so the metal will not plate out indiscriminately)
          4.   Various buffers and other chemicals designed to
               maintain bath stability and increase bath life.

     The chemistry of electroless plating is best demonstrated
     by examining electroless nickel plating.  The source of
     nickel is a salt such as nickel chloride or nickel sulfate,
     and the reducer is sodium hypophosphite.  There are
     several complexing agents which can be used, the most
     common ones being citric and glycolic acid.  The basic
     plating reactions proceed as follows:

          The nickel salt is ionized in water

               NiS04 = Ni+2 + S04~2

          There is then a reduction-oxidation reaction
          with nickel and sodium hypophosphite.

                .+2      -i
               Ni ^

               Ni +
                        £  3    £    £  t

          The sodium hypophosphite also reacts in the
          following manner:

                    P0~ + H~ = 2P + 2NaOH + 2H^O
                         111-21

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As can be seen in the equations above, both nickel and
phosphorus are produced, and the actual metal deposited
is a nickel-phosphorus alloy.  The phosphorus content can
be varied to produce different characteristics in the
nickel plate.

When electroless plating  is done on a plastic basis material,
catalyst application and acceleration steps are necessary  as
surface preparation operations.  These steps are considered
part of the electroless plating unit operation.

Immersion plating is a chemical plating process in which a
thin metal deposit is obtained by chemical displacement of
the basis metal.  Unlike electroless plating, it is not an
autocatalytic process.  In immersion plating, a metal will
displace from solution any other metal that is below it in
the electromotive series of elements.

The lower (more noble) metal will  be deposited from solution
while the more active metal (higher in the series)
will be dissolved.  A common example of immersion plating
is the deposition of copper on steel from an acid copper
solution.  Because of the similarity of the wastes pro-
duced and the materials involved, immersion plating is
considered part of the electroless plating unit operation.

Anodizing is an electrolytic oxidation process which con-
verts the surface of the metal to an insoluble oxide.
These oxide coatings provide corrosion protection, decora-
tive surfaces, a base for painting and other coating pro-
cesses, and special electrical and mechanical properties.
Aluminum is the most frequently anodized material, while
some magnesium and limited amounts of zinc and titanium
are also treated.

Although the majority of anodizing is carried out by
immersion of racked parts in tanks, continuous anodizing
is done on large coils of aluminum in a manner similar to
continuous electroplating.  For aluminum parts, the for-
mation of the oxide occurs when the parts are made anodic
in dilute sulfuric acid or dilute chromic acid solutions.
The oxide layer begins formation at the extreme outer sur-
face, and as the reaction proceeds, the oxide grows into the
metal.  The last formed oxide, known as the boundary layer,
is located at the interface between the base metal and the
oxide.  The boundary is extremely thin and nonporous.  The
sulfuric acid process is typically used for all parts fab-
ricated from aluminum alloys except for parts subject to
stress or containing recesses in which the sulfuric acid
solution may be retained and attack the aluminum.  Chromic
                      111-22

-------
     acid anodic coatings are more protective than sulfuric acid
     coatings and have a relatively thick boundary layer.  For
     these reasons, a chromic acid bath is used if a complete
     rinsing of the part cannot be achieved.

4.   Chemical Conversion Coating - This manufacturing operation
     includes chromating,phosphating, metal coloring and passi-
     vating.  These coatings are applied to previously deposited
     metal or basis material for increased corrosion protection,
     lubricity, preparation of the surface for additional
     coatings or formulation of a special surface appearance.
     In chromating, a portion of the base metal is converted to
     one of the components of the protective film formed by the
     coating solution.  This occurs by reaction with aqueous
     solutions containing hexavalent chromium and active organic
     or inorganic compounds.  Chromate coatings are most frequent-
     ly applied to zinc, cadmium, aluminum, magnesium, copper,
     brass, bronze and silver.  Most of the coatings are applied
     by chemical immersion although a spray or brush treatment
     can be used.  Changes in the solutions can impart a wide
     range of colors to the coatings from colorless to irides-
     cent yellow, brass, brown, and olive drab.  Additional
     coloring of the coatings can be achieved by dipping the
     parts in organic dye baths to produce red, green, blue,
     and other colors.

     Phosphate coatings are used to provide a good base for
     paints and other organic coatings, to condition the sur-
     faces for cold forming operations by providing a base for
     drawing compounds and lubricants, and to impart corrosion
     resistance to the metal surface by the coating itself or
     by providing a suitable base for rust-preventative oils or
     waxes.  Phosphate conversion coatings are formed by the
     immersion of iron, steel, or zinc plated steel in a dilute
     solution of phosphoric acid plus other reagents.  The
     method of applying the phosphate coating is dependent upon
     the size and shape of the part to be coated.  Small parts
     are coated in barrels immersed in the phosphating solution.
     Large parts, such as steel sheet and strip, are spray coated
     or continuously passed through the phosphating solution.
     Supplemental oil or wax coatings are usually applied after
     phosphating unless the part is to be painted.

     Metal coloring by chemical conversion methods produces a
     large group of decorative finishes.  This operation covers
     only chemical methods of coloring in which the metal surface
     is converted into an oxide or similar metallic compound.
     The most common colored finishes are used on copper, steel,
     zinc, and cadmium.
                        111-23

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Application of the color to the cleaned basis metal involves
only a brief immersion in a dilute aqueous solution.  The
colored films produced on the metal surface are extremely
thin and delicate.  Consequently, they lack resistance to
handling and the atmosphere.  A clear lacquer is often used
to protect the colored metal surface.  A large quantity of
copper and brass is colored to yield a wide variety of
shades and colors.  Shades of black, brown, gray, green and
patina can be obtained on copper and brass by use of appro-
priate coloring solutions.  The most widely-used colors for
ferrous metals are based on oxides which yield black, brown,
or blue colors.  A number of colors can be developed on zinc
depending on the length of immersion in the coloring solu-
tion.  Yellow, bronze, dark green, black and brown colors
can be produced on cadmium.  Silver, tin, and aluminum are
also colored commercially.  Silver is given a gray color by
immersion in a polysulfide solution such as ammonium
polysulfide.  Tin can be darkened to produce an antique
finish of pewter by immersion in a solution of nitric acid
and copper sulfate.

Passivation refers to forming a protective film on metals,
particularly stainless steel and copper, by immersion in
an acid solution.  Stainless steel is passivated in order
to dissolve any imbedded iron particles and to form a thin
oxide film on the surface of the metal.  Typical solutions
for passivating stainless steel include nitric acid and
nitric acid with sodium dichromate.  Copper is passivated
with a solution of ammonium sulfate and copper sulfate
forming a blue-green patina on the surface of the metal.

Etching and Chemical Milling - These processes are used to
produce specific design configurations and tolerances on
parts (or metal-clad plastic in the case of printed circuit
boards) by controlled dissolution with chemical reagents or
etchants.  Included in this classification are the processes
of chemical milling, chemical etching and bright dipping.
Chemical etching is the same process as chemical milling
except the rates and depths of metal removal are usually
much greater in chemical milling.  Typical solutions for
chemical milling and etching include ferric chloride,
nitric acid, ammonium persulfate, chromic acid, cupric
chloride, hydrochloric acid and combinations of these
reagents.  Bright dipping is a specialized form of etching
and is used to remove oxide and tarnish from ferrous and
nonferrous materials and is frequently performed just prior
to anodizing.  Bright dipping can produce a range of surface
appearances from bright clean to brilliant depending on the
surface smoothness desired for the finished part.  Bright
                    111-24

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dipping solutions usually involve mixtures of two or more
of sulfuric, chromic, phosphoric, nitric and hydrochloric
acids.  Also included in this unit operation is the
stripping of metallic coatings.

Cleaning involves the removal of oil, grease and dirt from
the surface of the basis material using water with or
without a detergent or other dispersing agent.  Alkaline
cleaning (both electrolytic and non-electrolytic) and acid
cleaning are both included.

Alkaline cleaning is used to remove oily dirt or solid
soils from workpieces.  The detergent nature of the
cleaning solution provides most of the cleaning action with
agitation of the solution and movement of the workpiece
being of secondary importance.  Alkaline cleaners are
classified into three types:  soak, spray, and electro-
lytic.  Soak cleaners are used on easily removed soil.
This type of cleaner is less efficient than spray or
electrolytic cleaners.  Spray cleaners combine the
detergent properties of the solution with the impact
force of the spray which mechanically loosens the soil.
Electrolytic cleaning produces the cleanest surface
available from conventional methods of alkaline cleaning.
The effectiveness of this method results from the strong
agitation of the solution by gas evolution and oxidation-
reduction reactions that occur during electrolysis.  Also,
certain dirt particles become electrically charged and are
repelled from the surface.  Direct current (cathodic) clean-
ing (anodic) cleaning the workpiece is the anode.  In
periodic  reverse current cleaning, the current is periodi-
cally reversed from direct current to reverse current.
Periodic reverse cleaning gives improved smut removal,
accelerated cleaning and a more active surface for any
subsequent surface finishing operation.

Acid cleaning is a process in which a solution of an in-
organic (mineral) acid, organic acid, or an acid salt, in
combination with a wetting agent or detergent, is employed
to remove oil, dirt, or oxide from metal surfaces.  Acid
cleaning done with various acid concentrations can be
referred to as pickling, acid dipping, descaling, or
desmutting.  The solution may or may not be heated and can
be an immersion or spray operation.  Agitation is normally
required with soaking, and spray is usually used with
complex shapes.  An acid dip operation may also follow
alkaline cleaning prior to plating.  Phosphoric acid mix-
tures are also in common use to remove oils and light rust
while leaving a phosphate coating that provides a paint base
or temporary resistance to rusting.  Strong acid solutions
are used to remove rust and scale prior to surface finishing,
                    111-25

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 7-   Machining is the general process of removing stock from a
      workpiece by forcing a cutting tool through the workpiece,
      removing a chip of basis material.  Machining operations
      such as turning, milling, drilling, boring, tapping, plan-
      ing, broaching, sawing and cutoff, shaving, threading,
      reaming, shaping, slotting, hobbing, filing, and chamfering
      are included in this definition.

 8.   Grinding is the process of removing stock from a workpiece
      by the use of a tool consisting of abrasive grains held by
      a rigid or semirigid binder.  The tool is usually in the
      form of a disk (the basic shape of grinding wheels), but
      may also be in the form of a cylinder, ring, cup, stick,
      strip, or belt.  The most commonly used abrasives are
      aluminum oxide, silicon carbide, and diamond.  The processes
      included in this unit operation are sanding (or cleaning to
      remove rough edges or excess material), surface finishing,
      and separating (as in cut-off or slicing operations).

 9.   Polishing is an abrading operation used to remove or smooth
      out surface defects (scratches, pits, tool marks, etc.)
      that adversely affect the appearance or function of a part.
      Polishing is usually performed with either a belt or wheel
      to which an abrasive such as aluminum oxide or silicone
      carbide is bonded.  Both wheels and belts are flexible and
      will conform to irregular or rounded areas where necessary.
      The operation usually referred to as buffing is included in
      the polishing operation.

10.   Barrel Finishing or tumbling is a controlled method of
      processing parts to remove burrs, scale, flash, and oxides
      as well as to improve surface finish.  Widely used as a
      finishing operation for many parts, it obtains a uniformity
      of surface finish not possible by hand finishing.  For
      large quantities of small parts it is generally the most
      economical method of cleaning and surface conditioning.

      Parts to be finished are placed in a rotating barrel or
      vibrating unit with an abrasive media, water or oil, and
      usually some chemical compound to assist in the operation.
      As the barrel rotates slowly, the upper layer of the work
      is given a sliding movement toward the lower side of the
      barrel, causing the abrading or polishing action to occur.
      The same results may also be accomplished in a vibrating
      unit, in which the entire contents of the container are
      in constant motion.

 11.   Burnishing is the process of finish sizing or smooth
      finishing a workpiece (previously machined or ground) by
      displacement, rather than removal, of minute surface
      irregularities.  It is accomplished with a smooth point
      or line-contact and fixed or rotating tools.
                         111-26

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12.  Impact Deformation is the process of applying an impact
     force to a workpiece such that the workpiece is permanently
     deformed or shaped.  Impact deformation operations include
     shot peening, peening, forging, high energy forming,
     heading, and stamping.

13.  Pressure Deformation is the process of applying force  (at
     a slower rate than an impact force) to permanently deform
     or shape a workpiece.  Pressure deformation includes
     operations such as rolling, drawing, bending, embossing,
     coining, swaging, sizing, extruding, squeezing, spinning,
     seaming, staking, piercing, necking, reducing, forming,
     crimping, coiling, twisting, winding, flaring or weaving.

14.  Shearing is the process of severing or cutting a
     workpiece by forcing a sharp edge or opposed sharp edges
     into the workpiece stressing the material to the point of
     shear failure and separation.

15.  Heat Treating is the modification of the physical properties
     of a workpiece through the application of controlled heating
     and cooling cycles.  Such operations as tempering, carburi-
     zing, cyaniding, nitriding, annealing, normalizing, austen-
     izing, quenching, austempering, siliconizing, martempering,
     and malleabilizing are included in this definition.

16.  Thermal Cutting is the process of cutting, slotting or
     piercing a workpiece using an oxyacetylene oxygen lance
     or electric arc cutting tool.

17.  Welding is the process of joining two or more pieces of
     material by applying heat, pressure or both, with or with-
     out filler material, to produce a localized union through
     fusion or recrystallization across the interface.  Included
     in this process are gas welding, resistance welding, arc
     welding, cold welding, electron beam welding, and laser
     beam welding.

18.  Brazing is the process of joining metals by flowing a  thin,
     capillary thickness layer of nonferrous filler metal into
     the space between them.  Bonding results from the intimate
     contact produced by the dissolution of a small amount  of
     base metal in the molten filler metal, without fusion  of  the
     base metal.  The term brazing  is used where the temperature
     exceeds 425°C (800°F).

19.  Soldering is the process of joining metals by flowing  a
     t:hin (capillary thickness) layer of nonferrous filler  metal
     into the space between them.  Bonding results from the in-
     timate contact produced by the dissolution of a small  amount
                         111-27

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     of base metal in the molten filler metal, without fusion
     of the base metal.  The term soldering is used where the
     temperature range falls below 425°C (800°).

20.  Flame Spraying is the process of applying a metallic coating
     to a workpiece using finely powdered fragments of wire,
     together with suitable fluxes, are projected through a cone
     of flame onto the workpiece.

21.  Sand Blasting is the process of removing stock, including
     surface films, from a workpiece by the use of abrasive
     grains pneumatically impinged against the workpiece.  The
     abrasive grains used include sand, metal shot, slag, silica,
     pumice, or natural materials such as walnut shells.

22.  Abrasive Jet Machining is a mechanical process for
     cutting hard brittle materials.  It is similar to sand
     blasting but uses much finer abrasives carried at high
     velocities (500-3000 fps) by a liquid or gas stream.  Uses
     include frosting glass, removing metal oxides, de-
     burring, and drilling and cutting thin sections of metal.

23.  Electrical Discharge Machining is a process which
     can remove metal with good dimensional control from any
     metal.  It cannot be used for machining glass, ceramics,
     or other nonconducting materials.  The machining action
     is caused by the formation of an electrical spark between
     an electrode, shaped to the required contour, and the
     workpiece.  Since the cutting tool has no contact with
     the workpiece, it can be made from a soft, easily worked
     material such as brass.  The tool works in conjunction with
     a fluid such as mineral oil or kerosene, which is fed to
     the work under pressure.  The function of this coolant is
     to serve as a dielectric, to wash away particles of eroded
     metal from the workpiece or tool, and to maintain a uniform
     resistance to flow of current.

     Electrical discharge machining is also known as spark
     machining or electronic erosion.  The operation was de-
     veloped primarily for machining carbides, hard nonferrous
     alloys, and other hard-to-machine materials.

24.  Electrochemical Machining is a process based on the
     same principles usedin electroplating except the workpiece
     is the anode and the tool is the cathode.  Electrolyte is
     pumped between the electrodes and a potential applied with
     the result that metal is rapidly removed.

     In this process, electrode accuracy is important since
     the surface finish of the electrode tool will be reproduced
     in the surface of the workpiece.  While copper is frequently
                          111-28

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     used as the electrode, brass, graphite, and copper-tungsten
     are also used.  The tool must be an electrical conductor,
     easy to machine, corrosion resistant, and able to conduct
     the quantity of current needed.  Although there is no
     standard electrolyte, sodium chloride is more generally
     used than others.

25.   Electron Beam Machining is a thermoelectric process.
     In electron beam machining, heat is generated by high
     velocity electrons impinging the workpiece, with the beam
     being converted into thermal energy.  At the point where
     the energy of the electrons is focused, it is transformed
     into sufficient thermal energy to vaporize the material
     locally.  The process is generally carried out in a vacuum.
     While the metal-removal rate of electron beam machining is
     approximately 0.01 milligrams per second, the tool is accur-
     ate and is especially adapted for micro-machining.  There
     is no heat affected zone or pressure on the workpiece and
     extremely close tolerances can be maintained.  The process
     results in X-ray emission which requires that the work area
     be shielded to absorb radiation.  At present the process is
     used for drilling holes as small as 0.0508 mm (0.002 in.)
     in any known material, cutting slots, shaping small parts,
     and machining sapphire jewel bearings.

26.   Laser Beam Machining is the process whereby a highly
     focused monochromatic collimated beam of light is used to
     remove material at the point of impingement on a workpiece.
     Laser beam machining is a thermoelectric process, and material
     removal is largely accomplished by evaporation although some
     material is removed in the liquid state at high velocity.
     Since the metal removal rate is very small, they are used
     for such jobs as drilling microscopic holes in carbides
     or diamond wire drawing dies and for removing metal in
     the balancing of high-speed rotating machinery.

     Lasers can vaporize any known material.  They have small
     heat affected zones and work easily with nonmetallic hard
     materials.

27.   Plasma Arc Machining is the process of material removal or
     shaping of a workpiece by a high velocity jet of high
     temperature ionized gas.  A gas (nitrogen, argon, or
     hydrogen) is passed through an electric arc causing it to
     become ionzied and raised to temperatures in excess of
     16,649°C (30,000°F).  The relatively narrow plasma jet melts
     and displaces the workpiece material in its path.  Because
     plasma machining does not depend on a chemical reaction
                         111-29

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     between the gas and the work material and because plasma
     temperatures are extremely high, the process can be used
     on almost any metal, including those that are resistant to
     oxygen-fuel gas cutting.  The method is of commercial  im-
     portance mainly for profile cutting of stainless steel and
     aluminum alloys.

28.  Ultrasonic Machining is a mechanical process designed  to
     effectively machine hard, brittle materials.  It removes
     material by the use of abrasive grains which are carried in
     a liquid between the tool and the work and which bombard
     the work surface at high velocity.  This action gradually
     chips away minute particles of material in a pattern
     controlled by the tool shape and contour.  A transducer
     causes an attached tool to oscillate linearly at a
     frequency of 20,000 to 30,000 times per second at an
     amplitude of 0.0254 to 0.127 mm (0.001 to 0.005 in).   The
     tool motion is produced by being part of a sound wave  energy
     transmission line which causes the tool material to change
     its normal length by contraction and expansion.  The tool
     holder is threaded to the transducer and oscillates linearly
     at ultrasonic frequencies, thus driving the grit particles
     into the workpiece.  The cutting particles, boron carbide
     and similar materials, are of a 280-mesh size or finer,
     depending upon the accuracy and the finish desired.  Opera-
     tions that can be performed include drilling, tapping, coin-
     ing, and the making of openings in all types of dies.
     Ultrasonic machining is used principally for machining
     materials such as carbides, tool steels, ceramics, glass,
     gem stones, and synthetic crystals.

29.  Sintering is the process of forming a mechanical part  from
     a powdered metal by fusing the particles together under
     pressure and heat.  The temperature is maintained below
     the melting point of the basis metal.

30.  Laminating is the process of adhesive bonding layers of
     metal, plastic, or wood to form a part.

31.  Hot Dip Coating is the process of coating a metallic
     workpiece with another metal by immersion in a molten  bath
     to provide a protective film.  Galvanizing (hot dip zinc)
     is the most common hot dip coating.

32.  Sputtering is the process of covering a metallic or non-
     metallic workpiece with thin films of metal.  The surface
     to be coated is bombarded with positive ions in a gas
     discharge tube, which is evacuated to a low pressure.
                         111-30

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33.  Vapor Plating is the process of decomposition of a metal or
     compound upon a heated surface by reduction or decomposition
     of a volatile compound at a temperature below the melting
     point of either the deposit or the basis material.

34.  Thermal Infusion is the process of applying a fused zinc,
     cadmium, or other metal coating to a ferrous workpiece by
     imbuing the surface of the workpiece with metal powder or
     dust in the presence of heat.

35.  Salt Bath Descaling is the process of removing surface
     oxides or scalefrom a workpiece by immersion of the
     workpiece in a molten salt bath or a hot salt solution.
     Molten salt baths are used in a salt bath - water quench -
     acid dip sequence to clean hard-to-remove oxides from
     stainless steels and other corrosion-resistant alloys.
     The work is immersed in the molten salt (temperatures range
     from 400 - 540 degrees C), quenched with water, and then
     dipped in acid.  Oxidizing, reducing, and electrolytic
     baths are available, and  the particular type needed is
     dependent on the oxide to be removed.

36.  Solvent Degreasing is a process for removing oils and grease
     from the surfaces of a workpiece by the use of organic
     solvents, such as aliphatic petroleums  (eg-kerosene, naptha),
     aromatics (eg-benzene, toluene), oxygenated hydrocarbons
     (eg-ketones, alcohol, ether), halogenated hydrocarbons
     (eg-l,l,l-trichloroethane, trichloroethylene, methylene
     chloride), and combinations of these classes of solvents.
     Solvent cleaning can be accomplished by either the liquid or
     vapor phase.  Solvent vapor degreasing  is normally quicker
     than solvent liquid degreasing.  However, ultrasonic
     vibration is sometimes used with liquid solvent so as to
     decrease the required immersion time with complex shapes.
     Solvent cleaning is often used as a precleaning operation
     such as prior to the alkaline cleaning  that precedes plating,
     as a final cleaning of precision parts, or as a surface pre-
     paration for some painting operations.

     Emulsion cleaning is a type of solvent  degreasing that  uses
     common organic solvents (eg-kerosene, mineral oil, gylcols,
     and benzene) dispersed in an aqueous medium with the aid of
     an emulsifying agent.  Depending on the solvent used, clean-
     ing is done at temperatures from room temperature to 82°C
     (180°F).  This operation  uses less chemical than solvent
     degreasing because of the lower solvent concentration
     employed.  The process is used for rapid superficial clean-
     ing and is usually performed as emulsion spray cleaning.
                         111-31

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37.   Paint Stripping is the process of removing an organic coating
     from a workpiece.   The stripping of such coatings is usually
     performed with caustic, acid, solvent, or molten salt.

38.   Painting is the process of applying an organic coating
     to a workpiece.  The application of coatings such as paint,
     varnish, lacquer,  shellac, and plastics by processes such
     as spraying, dipping, brushing, roll coating, lithographing,
     and wiping are included.  Spray painting is by far the most
     common and can be  used with nearly all varieties of paint.
     The paint can be sprayed manually or automatically, hot
     or cold, and it may be atomized with or without compressed
     air to force the paint through an orifice.  Other processes
     included under this unit operation are printing, silk
     screening and stenciling.

39.   Electrostatic Painting is the application of electrosta-
     tically charged paint particles to an oppositely charged
     workpiece followed by thermal fusing of the paint particles
     to form a cohesive paint film.  Usually the paint is applied
     in spray form and  may be applied manually or automatically,
     hot or cold, and with or without compressed air atomization.
     Both waterborne and solvent-borne coatings can be sprayed
     electrostatically.

40.   Electropainting is the process of coating a workpiece by
     either makingit anodic or cathodic in a bath that is
     generally an aqueous emulsion of the coating material.  The
     electrodeposition  bath contains stabilized resin, dispersed
     pigment, surfactants, and sometimes organic solvents in water.
     Electropainting is used primarily for primer coats because
     it gives a fairly  thick, highly uniform, corrosion resistant
     coating in relatively little time.

41.   Vacuum Metalizing  is the process of coating a workpiece
     with metal by flash heating metal vapor in a high-vacuum
     chamber containing the workpiece.  The vapor condenses on
     all exposed surfaces.

42.   Assembly is the fitting together of previously manufactured
     parts or components into a complete machine, unit of a
     machine, or structure.

43.   Calibration is the application of thermal, electrical, or
     mechanical energy  to set or establish reference points
     for a component or complete assembly.

44.   Testing is the application of thermal, electrical, or
     mechanical energy  to determine the suitability or function-
     ality of a component or complete assembly.
                         111-32

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                         SECTION IV

                   INDUSTRY CATEGORIZATION
INTRODUCTION

The primary purpose of industry categorization is to establish
groupings within the Metal Finishing Category (MFC) such that
each group (subcategory) has a uniform set of effluent limita-
tions.  This requires that the elements of each group be cap-
able of using similar treatment technologies to achieve the
effluent limitations.  Thus, the same wastewater treatment and
control technology is applicable within a subcategory and a uni-
form treated effluent results from the application of a specific
treatment and control technology.  This section presents the sub-
categories established for the Metal Finishing Category and ex-
plains the rationale for their selection.

There are two main components of categorization:  first, the
identification of subcategories that are suitable for the same
effluent limitations; and second, the selection of a discharge
limiting criterion that allows quantification of the effluent
limitations.  The subsections which follow deal with each of
these major considerations.

CATEGORIZATION BASIS

After reviewing the fundamental aspects of the Metal Finishing
Category, the following categorization bases were selected for
consideration in establishing subcategories:

     1.   Raw waste characteristics
     2.   Manufacturing processes
     3.   Raw materials (basis and process)
     4.   Product type or production volume
     5.   Size and age of facility
     6.   Number of employees
     7.   Water usage
     8.   Individual plant characteristics

After examination of these categorization bases, the raw waste
characteristics were selected as the basis for subcategorization.
Since treatability is directly related to the characteristics of
the raw wastes, these are a  natural choice for subcategorization.
This categorization approach provides initial subdivision  into
two constituents, namely:  inorganic and organic wastes.   These
can then be further subdivided into the specific types of  waste
that occur in each of these  two major areas.  Applying this,  the
raw wastes from all plants within the Metal  Finishing Category are
grouped into the following seven  (7) subcategories:
                              IV-1

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MAJOR SUBDIVISION


INORGANIC WASTES
ORGANIC WASTES
SUBCATEGORY
1.
2.
3.
4.
5.
6.
7.
Common metals
Precious metals
Completed metals
Chromium (hexavalent)
Cyanide
Oils
Solvents
All of the process raw wastes resulting from each of the 44  indi-
vidual unit operations, previously defined and described in  Sec-
tion III, are encompassed by one or more of these waste charac-
teristic subcategories.  Table 4-1 presents a tabulation of  the
manufacturing unit operations and the characteristics of the raw
waste that they have the potential to generate (the subcategories).
Thus a direct relationship is provided for the treatment system re-
quirements as a function of the unit operations performed at a manu-
facturing facility.  Subsequent sections of this document further
describe the specifics of the relationship between the unit  opera-
tions performed; the wastes they produce; and the various levels of
treatment technology and systems applicable to guideline limita-
t ions.

Each selected raw waste subcategory has:

     1.   Distinct waste characteristics since this is the
          basis for subcategorization

     2.   A uniform treated effluent resulting from the
          application of the same waste treatment technology

The following paragraphs discuss other approaches that were  con-
sidered as bases for further subdividing the raw waste characteris-
tics subcategory and the rationale for further subdivision being
unnecessary.

Manufacturing Processes

The manufacturing processes employed by the Metal Finishing  Cate-
gory are fully represented by the 44 unit operations that were
defined in Section III.  Subdivision by manufacturing process could
adequately define waste characteristics.  However, unit operation
subdivision would be overly complex in determining the waste loads
and effluent limitations due to the number of combinations of pro-
cesses that exist in this category.  In addition, subdivision on
the basis of each of the unit operations is not uniquely suited to
define waste characteristics since many operations generate  the
same waste constituents.  Unit operations with similar waste char-
acteristics could be combined to form individual subcategories and
thus effectively provide a categorization based upon waste
                              IV-2

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characteristics.  Furthermore, as explained previously, a direct
correlation exists between the unit operations performed and  treat-
ment technology needed via the selected waste characteristics sub-
categorization.  Therefore, manufacturing process variations  are
inherently accounted for by their waste characteristics and no
further subdivision on the basis of manufacturing process is  required.

Raw Materials

There is a wide variation in basis materials, process materials,
and process chemicals used within this industry and all wastes are
a direct result of this material usage.  Therefore, they are  in-
trinsically accounted for since the selected waste characteristic
subcategories are directly related to the physical and chemical
properties of the raw materials (e.g.-metals, oils, solvents).

Product Type or Production Volume

The products manufactured by the Metal Finishing Category cover
virtually the entire spectrum of metallic goods.  There are
specific differences in manufacturing operations and many vari-
eties of raw and process materials are used throughout the cate-
gory.  However, wastewaters resulting from the manufacture of many
different products have the same waste treatment requirements and
this is accounted for by subcategorization in terms of waste  char-
acteristics .

The production volume influences the mass of pollutants discharged
but does not alter the waste constituents.  Therefore, the quantity
of work processed is not appropriate as a basis for subcategoriza-
tion.

Size and Age of Facility

The nature of the manufacturing processes for the Metal Finishing
Category is the same in all facilities regardless of their size.
Size is an insufficient criterion for further subdivision since the
waste characteristics of a plant depend on the raw materials  and
the unit operations employed.

The relative age of plants is important but is not a suitable basis
for subdividing the raw waste subcategory because it does not con-
sider those items which affect the effluent discharged.  The  age of
a plant has no bearing on the resulting waste characteristics or the
required waste treatment.

Number of Employees

The number of employees is not an appropriate basis for subdivision
since identical manufacturing operations can be performed manu-
                              IV-3

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ally or by automatic machinery.  For example, a specific operation
might be accomplished manually by six (6) machine operators for a
particular production level, which if automated, might reguire only
one operator to produce an equivalent production output.  In both
cases, the resulting waste characteristics are identical if all
other factors are the same.

Water Usage

Water usage is an insufficiently comprehensive factor upon which
to subdivide raw waste characteristics.  While water use is a key
element in the limitations established,  it does not necessarily
relate directly to the source of the waste.  Water usage must be
related to some other factor(s) to be an effective subdivision
base.  One significant factor is the manufacturing unit operation
utilizing the water since it dictates the water usage.

In addition, water usage for each unit operation may vary from
plant to plant depending upon such factors as the rinsing method
employed.  Total rinse water usage varies significantly with the
type of rinse (e.g.-single stage rinsing, series rinsing, counter-
current rinsing, etc).  For these reasons, water usage is not an
appropriate basis for further subdivision.

Individual Plant Characteristics

Individual plant characteristics do not  provide a proper basis for
subcategorization because they do not affect the process wastewater
characteristics of the plant.  Plants in different geographical
areas may have similar wastewater characteristics.

Summary of Categorization Bases

For this study, waste characteristics were selected as the basis
for subcategorization.  The primary division of waste characteristics
was the grouping of wastes into inorganic and organic compounds.
These two groups were then subdivided into five inorganic and two
organic waste characteristic subcategories.  All of the raw waste-
waters produced in the Metal Finishing Category are clearly defined
by and included in these seven subcategories:  common metals, pre-
cious metals, complexed metals, hexavalent chromium, cyanide, oils,
and solvents.  These seven subcategories encompass the pollutants
contained in the wastewaters generated by all combinations of unit
operations, raw materials, and process materials and chemicals em-
ployed in the Metal Finishing Category.

EFFLUENT LIMITATION BASE

The following paragraphs deal with the selection of the effluent
limitation parameter which is used to quantify the allowable
pollutant discharge.
                              IV-4

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Selection of the Limitation Parameter

The raw waste characteristics were selected as the basis for cate-
gorization and seven distinct subcategories have been defined.  A
quantitative criterion upon which to base effluent limitations  is
also required.  Since pollutants are measured in terms of their
concentration (mg/l)f concentration itself is the obvious primary
consideration for quantification of the limitations.  Utilization
of concentration has the following advantages:

     1.   Concentration is a directly monitorable parameter
          using fundamental sampling and analysis techniques.

     2.   Industry, via its self-monitoring data, has the
          opportunity to rapidly recognize and respond to
          deviations from the limitations.

     3.   Application of pertinent treatment and control
          systems to either new or existing manufacturing
          facilities is straightforward because these systems
          are selected to provide specific effluent concentra-
          tion levels for specific raw wastewater characteris-
          tics (which are similar for all sources within a
          subcategory).

     4.   Enforcement of limitation guidelines and regulations
          is drastically simplified.  Historically, a produc-
          tion related parameter for this industry such as a
          combination of the product surface area and the number
          of particular wastewater producing operations performed,
          has been used in conjunction with the concentration and
          process flow rate to quantify limitations  (e.g. limita-
          tion in terms of mg/operation-sq.m. for electroplating
          operations).  The application of this type of para-
          meter to quantify the electroplating limitations has
          proven to be difficult to understand, implement, and
          enforce.  Several specific problems associated with
          the use of a production related parameter for the
          Metal Finishing Category are:

          a.   Differences in part configuration are not
               accounted for by merely using a surface
               area basis such as was used in the past for
               electroplating.

          b.   It is often difficult to determine the pro-
               duction level.  For example, the overall
               area of barrel plated items such as miscel-
               laneous jewelry varies constantly throughout
               a normal production day.  To determine pro-
               duction (surface area plated) requires measure-
               ment of each individual part.
                              IV-5

-------
     c.   Mass based limitations are difficult to implement
          if either the production sequence or processed
          parts are constantly changing, as is especially
          the case for job shops.

     d.   It is often difficult to establish that which
          constitutes a single wastewater producing opera-
          tion since operations can alternately be dry
          or wet, and since the sequence of performing
          operations is subject to variation.

The use of concentration alone as the limitation criterion allows
direct measurement and analysis of the treated effluent to verify
compliance with the regulations.
                              IV-6

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           TABLE 4-1




WASTE CHARACTERISTIC DISTRIBUTION
^"""-•^^^ WASTE
^^^--^CHARACTERISTICS
UNIT ^^^
OPERATION ^""^\^^
1. Electroplating
2. Electroless Plating
3. Anodizing
4. Conversion Coating
5. Etching (Chem. Milling)
6. Cleaning
7. Machining
8. Grinding
9. Polishing
10. Tumbling
11. Burnishing
12. Impact Deformation
13. Pressure Deformation
14. Shearing
15. Heat Treating
16. Thermal Cutting
17. Welding
18. Brazing
19. Soldering
20. Flame Spraying
21. Sand Blasting
22. Other Abr. Jet Machining
23. Elec. Discharge Machining
24. Electrochemical Machining
25. Electron Beam Machining
26. Laser Beam Machining
27. Plasma Arc Machining
28. Ultrasonic Machining
INORGANICS
Common Precious Complexed Chromium
Metals Metals Metals (Hexavalent) Cyanide
XX XX
XXX X
X X
XX XX
XXX X
XXX X X
X
X
X X
X XX
XX X
X
X
X
X X
X
X
X
X
X
X
X
X
X X
X
X
X
X
ORGANICS
Oils Solvents





X X
X
X
X
X
X
X
X
X
X X






X
X
X X





-------
00
                                                     TABLE 4-1




                                          WASTE CHARACTERISTIC DISTRIBUTION
^^\^^ WASTE
^-^CHARACTERISTICS
UNIT ^"^\^
OPERATION ^^\^^
29. Sintering
30. Laminating
31. Hot Dip Coating
32. Sputtering
33. Vapor Plating
34. Thermal Infusion
35. Salt Bath Descaling
36. Solvent Degreasing
37. Paint Stripping
38. Painting
39. Electrostatic Painting
40. Electropainting
41. Vacuum Metalizing
42. Assembly
43. Calibration
44. Testing
INORGANICS

Common Precious Complexed Chromium
Metals Metals Metals (Hexavalent) Cyanide
X
X
X
X
X
X
X
X
X
X
X X
X
X
X
X
X
ORGANICS


Oils Solvents






X
X X
X X
X X
X X
X

X X
X
X

-------
Manufacturing Facility
Raw Waste Sources
• • • • i
Raw Waste Discharge ^ ^k ,
(Treatment System '' '' '
Influent) ,, , (
Waste Treatment ! Oily Waste , j Chromium j
1 I '
(If Applicable) ! Removal | | Reduction j
1 	 	 J L 	 	 i
Treated
Effluent *^v
<
j Met
t Remc
<
\
Final
Eff.
Common -* 	 1
Metals
I 	 	 1 1 	
I Cyanide i j C^P1
i ! Met
I Destruction | 1 Rem=
1 	 . 	 i 1 	
•B 3
s g
Without Cyanide
}G Raw Waste
(Common Metals)
ZT~!
?val I
	 1
kz Treated
7 Effluent
i
rreated
Luent
Solvents
.-c T
.
i
}E OF i
1
f ' ' '
exed ' Precious , |
als ! Metals I
val 1 Recovery I |
. 	 i 1 	 , 	 1 	 1 |
1 Hauled Or
jf Reclaimed
"1
1
1
1
Hauled Or
Reclaimed
^ Stream Locations
	 Optional Route
                Note: Discharge from precious metals recovery may be
                      hauled in alternative ways, depending on the
                      recovery method in use.
       FIGURE 4-1

WASTE EFFLUENT SCHEMATIC

-------
                         SECTION V

                   WASTE CHARACTERIZATION
INTRODUCTION

This section presents the water uses, identifies the waste
constituents, and quantifies the waste constituents that originate
in the Metal Finishing Category.  Published literature, data
collection portfolio responses, and actual sampling data were
reviewed in order to obtain data for this section.  In general,
quantitative raw waste information was not included in the data
collection portfolios.  When such information was included, it
was fragmented, incomplete and nearly impossible to correlate.
Therefore, the raw waste data presented are derived from an
analysis of samples taken at visited plants, downstream of the
manufacturing sources and prior to any waste treatment.  All
parameters analyzed were measured as total rather than dissolved
and are expressed in terms of milligrams per liter  (mg/1).

This section is organized in the following manner.  First, sources
of industry data are outlined.  This is followed by a discussion
of water usage within the Metal Finishing Category.  The next
section discusses waste characteristics for each of the forty-
four unit operations.  Finally, there is a description of the
parameters found in each of the seven subcategories that were
outlined in Section IV:

          Common metals
          Precious metals
          Complexed metals
          Hexavalent chromium
          Cyanide
          Oils
          Solvents
WATER USAGE IN THE METAL FINISHING CATEGORY

Water is used for rinsing workpieces, washing away spills, air
scrubbing, process fluid replenishment, cooling and lubrication,
washing of equipment and workpieces, quenching, spray booths,
and assembly and testing.  Descriptions of these uses follow.

Rinsing

A large proportion of the water usage in the Metal Finishing
category is for rinsing.  This water is used to remove the film
(fluids and solids) that is deposited on the surfaces of  the
workpieces during the preceding process.  As a result of  this
                               V-l

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rinsing, the water becomes contaminated with the constituents of
the film.  Rinsing can be used in some capacity after virtually
all of the unit operations covered by the Metal Finishing Cate-
gory and is considered to be an integral part of the unit operation
that it follows.

Spills and Air Scrubbing

Water is used for washing away floor spills and for scrubbing of
ventilation exhaust air.  In both cases these wastewaters are
contaminated with constituents of process materials and dirt.

Process Fluid Replenishment

As process fluids (e.g. - cleaning solutions, plating solutions,
paint formulations, etc) become exhausted or spent, new solu-
tions have to be made up, with water a major constituent of these
solutions.  When a fluid is used at high temperature, water must
be added periodically to make up for evaporative losses.  Exhaus-
ted or spent process solutions to be dumped are either collected
in sumps for batch processing or are slowly metered into dis-
charged rinse water prior to treatment.

Cooling and Lubrication

Coolants and lubricants in the form of free oils, emulsified oils,
and grease are required by many metal removal operations.  The
films and residues from these fluids are removed during cleaning,
washing, or rinsing operations and these constituents contaminate
other fluids.  In addition, spent fluids in the sumps represent a
further waste contribution that is processed either batch wise
(segregated)  or is discharged to other waste streams.

Water from Auxiliary Operations

Auxiliary operations such as plating or painting rack stripping
are essential to plant operations; waters used in these operations
do become contaminated and require treatment.

Washing

Water used for washing workpieces or for washing equipment such as
filters, pumps and tanks picks up residues of concentrated process
solutions, salts, or oils and is routed to an appropriate wastewater
stream for treatment.

Quenching

Workpieces which have undergone an operation involving intense heat
such as heat treating, welding, or hot dip coating are frequently
quenched or cooled in aqueous solutions to achieve the desired pro-
                               V-2

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parties or to facilitate subsequent handling of the part.  These
solutions become contaminated and require treatment.

Spray Booths

Plants which employ spray painting processes use spray booths  in
order to capture oversprayed paint in a particular medium.  Many
of these booths use water curtains to capture the paint overspray.
The paint is directed against a flowing stream of water, which
scrubs the air so that paint and solvents are not exhausted to
the outside atmosphere.  The paint collected in the water  is re-
moved by skimming or by use of an ultrafilter and the water is
reused in the curtain.  This water may occassionally be dumped.

Testing and Calibration

Many types of testing such as leak, pressure, and performance
testing, make use of large quantities of water that become con-
taminated.

Water Use Summary

Table 5-1 is a listing of the unit operations covered in the Metal
Finishing Category and shows the operations that can utilize water.
The table is broken down according to degree of water use:  signifi-
cant water usage, minimal water usage and zero discharge.  The
operations found to have zero discharge were determined by an
analysis of visited plants in the Metal Finishing Category data
base; the data are shown in Table 5-2.  The data shown include
total number of occurences of each unit operation, number of zero
discharges and the percentage of the total occurence with zero
discharge.  The unit operations considered to have zero discharge
are electron beam machining, laser beam machining, plasma arc
machining, ultrasonic machining, sintering, sputtering, vapor
plating, thermal infusion, vacuum metalizing and calibration.
Table 5-3 shows the zero discharge data from the DCP data bases
for comparison.

Figure 5-1 displays the ranges of flows which may be found within
the Metal Finishing Category.  This figure is based on flow infor-
mation obtained from visited plants.  As might be expected, the
majority of the plants falll within a medium flow range (1,000-
10,000 GPH) rather than at the extremes of the scale.
                               V-3

-------
                          Table 5-1
         WATER USAGE BY METAL FINISHING OPERATIONS
               (BASED ON C/J DATA & DCP DATA)
Unit
Operation

 1.  Electroplating
 2.  Electroless Plating
 3.  Anodizing
 4.  Conversion Coating
 5.  Etching (Chemical Milling)
 6.  Cleaning
 7.  Machining
 8.  Grinding
 9.  Polishing
10.  Tumbling
11.  Burnishing
12.  Impact Deformation
13.  Pressure Deformation
14.  Shearing
15.  Heat Treating
16.  Thermal Cutting
17.  Welding
18.  Brazing
19.  Soldering
20.  Flame Spraying
21.  Sand Blasting
22.  Other Abr. Jet Machining
23.  Elec. Discharge Machining
24.  Electrochemical Machining
25.  Electron Beam Machining
26.  Laser Beam Machining
27.  Plasma Arc Machining
28.  Ultrasonic Machining
29.  Sintering
30.  Laminating
31.  Hot Dip Coating
32.  Sputtering
33.  Vapor Plating
34.  Thermal Infusion
35.  Salt Bath Descaling
36.  Solvent Degreasing
37.  Paint Stripping
38.  Painting
39.  Electrostatic Painting
40.  Electropainting
41.  Vacuum Me talizing
42.  Assembly
43.  Calibration
44.  Testing
Major
Water
Usage
  x
  X
  X
  X
  X
  X
  X
  X
  X


  X
  X
  X
  X
  X
Minimal
Water
Usage
Zero
Discharge
            x
            x
            X
            X
            X
            X

            X


            X
            X
            X
            X
            X
                       X
                       X
                       X
                       X
                       X
                       X
                       X
                       X
                       X


                       X
                                  V-4

-------
                                       Table  5-2
                      DETERMINATION OF  ZERO DISCHARGE  OPERATIONS
                                        Number  of
       Unit Operation                   Occurences

   1.   Electroplating
   2.   Electroless Plating
   3.   Anodizing
   4.   Conversion Coating
   5.   Etching & Chemical Milling
   6.   Cleaning
   7.   Machining
   8.   Grinding
   9.   Polishing
  10.   Tumbling (Barrel Finishing)
  11.   Burnishing
  12.   Impact Deformation
  13.   Pressure Deformation
  14.   Shearing
  15.   Heat Treating
  16.   Thermal Cutting
  17.   Welding
  18.   Brazing
  19.   Soldering
  20.   Flame Spraying
  21.   Sand Blasting
  22.   Other Abrasive Jet Machining
  23.   Electrical Discharqe Machining
  24.   Electrochemical Machining
  25.   Electron Beam Machining
  26.   Laser Beam Machining
  27.   Plasma Arc Machining
  28.   Ultrasonic Machining
  29.   Sintering
  30.   Laminating
  31.   Hot Dip Coating
  32.   Sputtering
  33.   Vapor Plating
  34.   Thermal Infusion
  35.   Salt Bath Descaling
**36.   solvent Degreasing
  37.   Paint Stripping
  38.   Painting
  39.   Electrostatic Painting
  40.   Electropainting
  41.   Vacuum Metalizing
  42.   Assembly
  43.   Calibration
  44.   Testing

 *These data are from a 41 plant sampled data base.
  from a separate 99 plant sampled  data base.
Number of
  Zero
Dischargers
Percentage of
   Zero
 Dischargers
32
9
12
11
8
41
60
62
42
53
16
20
39
37
37
18
52
28
38
5
20
20
12
9
6
5
4
2
4
11
4
2
3
3
13
-
50
18
15
15
7
61
24
70
0
0
0
0
0
0
8
31
30
20
10
18
34
33
17
17
46
25
33
3
18
18
9
3
6
5
4
2
4
10
3
2
3
3
2
-
3
0
0
0
7
57
24
40
0.0
0.0
0.0
0.0
0.0
0.0
13.3
50.0
71.4
37.8
62.5
90.0
87.2
89.2
45.9
94.4
88.5
89.3
86.8
60.0
90.0
90.0
75.0
33.3
100.0
100.0
100.0
100.0
100.0
91.0
75.0
100.0
100.0
100.0
15.4
0.0
6.0
0.0
0.0
0.0
100.0
93.4
100.0
57.0
 All other data are
**Not included in the 99 plant data base.   Other data indicate that this
  operation consistently generates wastewater.
                                V-5

-------
                                Table 5-3
               DETERMINATION OF ZERO DISCHARGE OPERATIONS
                             (DCP DATA BASE)
     Unit Operation

 1.  Electroplating
 2.  Electroless Plating
 3.  Anodizing
 4.  Conversion Coating
 5.  Etching & Chemical Milling
 6.  Cleaning
 7.  Machining
 8.  Grinding
 9.  Polishing
10.  Tumbling (Barrel Finishing)
11.  Burnishing
12.  Impact Deformation
13.  Pressure Deformation
14.  Shearing
15.  Heat Treating
16.  Thermal Cutting
17.  Welding
18.  Brazing
19.  Soldering
20.  Flame Spraying
21.  Sand Blasting
22.  Other Abrasive Jet Machining
23.  Electrical Discharge Machining
24.  Electrochemical Machining
25.  Electron Beam Machining
26.  Laser Beam Machining
27.  Plasma Arc Machining
28.  Ultrasonic Machining
29.  Sintering
30.  Laminating
31.  Hot Dip Coating
32.  Sputtering
33.  Vapor Plating
34-  Thermal Infusion
35.  Salt Bath Descaling
36.  Solvent Degreasing
37.  Paint Stripping
38.  Painting
39.  Electrostatic Painting
40.  Electropainting
41.  Vacuum Metalizing
42.  Assembly
43.  Calibration
44.  Testing
                                       Number of
                                       Occurences

                                        1100
                                         207
                                         233
                                         490
                                         177
                                        1221
                                         241
                                         204
                                          80
                                          41
                                          11
                                          36
                                          48
                                          96
                                          38
                                          32
                                         162
                                          75
                                          87
                                           7
                                          44
                                           8
                                          12
                                           3
                                           0
                                           1
                                           4
                                           2
                                           3
                                          17
                                           7
                                           1
                                           0
                                           0
                                           2
                                          77
                                          16
                                          97
                                           9
                                           2
                                           2
                                         167
                                          46
                                          93
 Number of
   Zero
 Dischargers

     0
     0
     0
     0
     0
     0
   200
   166
    79
    15
     8
    35
    46
    95
    29
    30
   158
    75
    82
     7
    44
     7
     9
     1
     0
     1
     4
     0
     3
    16
     3
     1
     0
     0
     1
    28
     8
    84
     9
     2
     2
   165
    45
    82
Percentage 01
   Zero
 Dischargers

     0.0
     0.0
     0.0
     0.0
     0.0
     0.0
    83.0
    81.5
    98.8
    36.6
    72.7
    97.2
    95.8
    98.9
    76.3
    93.7
    97.5
   100.0
    94.2
   100.0
   100.0
    87.5
    75.0
    34.0

   100.0
   100.0
   100.0
   100.0
    94.1
    42.8
   100.0
    50.0
    36.4
    50.0
    86.6
   100.0
   100.0
   100.0
    98.8
    97.8
    88.0
*These data are from a 1221 plant DCP data base
 separate 365 plant DCP data base.
All other data are from a
                                   V-6

-------
                  Flow  (gph)
                 FIGURE 5-1
FLOW RANGES WITHIN THE METAL FINISHING CATEGORY
                     V-7

-------
Tables 5-4 through 5-9 present data on the contribution of the
various subcategory waste streams toward the total flow of a
plant.  For each visited plant where flows of discrete subcategory
waste streams could be measured, the tables present total waste-
water flow, subcategory waste stream flow and percentage contri-
bution of the subcategory waste stream flow.

Table 5-4 shows flow data for those visited plants which had
common metals waste streams measured prior to mixing with other
pretreated wastewaters.  The average contribution of these streams
to the total wastewater flow is 62.4% (range of .007-100%).  All of
the plants visited and sampled had a waste stream requiring common
metals treatment.

Table 5-5 contains flow data for those plants with precious metals
subcategory wastewater.  Of the plants visited, 4.8% of them had
production processes which generated precious metals wastewater.
The typical precious metals wastewater flow contribution is 21.5%.

Table 5-6 presents flow data for those plants with segregated
complexed metals waste streams.  Although additional plants have
processes which generate complex metal wastes, their wastes are
not segregated.  The average contribution of the complexed metal
streams at those plants listed in the table is 22.2%.

Table 5-7 presents the flow contribution of hexavalent chromium
wastewater streams.  Of the plants visited and sampled, 42.5%
have segregated hexavalent chromium waste streams.  The average
flow contribution of these waste streams to the total wastewater
stream is 28.7%.

Table 5-8 presents flow data on cyanide bearing waste streams.
As shown on the table, at those plants with cyanide wastes, the
average contribution of the cyanide bearing stream toward the
total wastewater generated is 28.8% (range: 0.1-100%).  Of the
plants visited and sampled, 31.2% have segregated cyanide bearing
wastes.

Table 5-9 presents data for the flow of segregated oily wastewater.
Segregated oily wastewater is defined as oil waste collected from
machine sumps and process tanks that is kept segregated from
other wastewaters until it has been treated by an oily waste
removal system.  The plants identified in Table 5-9 , which make
up 12.4% of the plants visited, are known to segregate their
oily wastes.  The average contribution of their oily wastes to
this total wastewater flow is 6.6%, with a range of nearly zero
to 55.4%.
                              V-8

-------
                                   TABLE 5-4
                        COMMON METALS STREAM CONTRIBUTION
PLANT ID
01003
02032
02033
02062
03043
04069
04071
06091
06110
06960
07001
08007
11068
11103
11108
12002
12061
12065
15608
17050
18538
19068
20022
20083
21003
21066
25010
30054
30165
30166
33028
33050
36048
36178
38052
40060
40063
44062
46025
COMMON METALS
STREAM FLOW (gpd)
12,280
57,062
37,739
11,039
980
156,710
93,723
53,350
237,914
27,636
3,204
7,209
164,713
147,282
82,669
259,927
250,405
49,983
74,120
5,287
81,482
6,429
592,550
61,112
1,592
58,127
801
904
3,845
73
2,595
11
6,069
134
4,792
76,421
9,019
54,846
96
TOTAL PLANT
DISCHARGE (gpd)
12,280
78,097
66,005
11,039
980
197,012
194,576
244,402
237,914
43,076
3,204
9.772
188,376
169.199
82,669
466,696
630,745
724,388
89,302
5,287
895,410
8,128
592,550
86,073
13,377
82,684
801
18,083
769,015
6,108
2,595
144,190
6,729
110,305
14,178
76,421
98,029
74,418
96
% OF
TOTAL FLOW
100.
73.0
57.2
100.
100.
79.5
48.2
21.8
100.
64.1
100.
73.8
87.4
87.0
100.
55.7
39.7
6.9
83.0
100.
9.1
79.1
100.
71.0
11.9
70.3
100.
5.0
0.5
1.2
100.
0.007
90.2
0.1
33.8
100.
9.2
73.7
100.
Average Contribution = 62.4%
                                  V-9

-------
                         TABLE 5-5
            PRECIOUS METALS STREAM CONTRIBUTION

                  PRECIOUS METALS       TOTAL PLANT        % OF
PLANT ID         STREAM FLOW (gpd)     DISCHARGE (gpd)    TOTAL FLOW
02033
06090
19069
21003
30054
34051
36623
14,749
2,403
900
4,085
5,413
70
77,141
66,005
169,423
3,600
13,377
21,840
1,800
365,042
22.3
1.4
25
30.5
24.7
3.9
21.1
   Average Contribution = 21.5%
                              V-10

-------
                                    TABLE 5-6
                       COMPLEXED METALS STREAM CONTRIBUTION
PLANT ID
02032
02033
04069
04071
06097
12065
15608
20083
34051
36048
COMPLEXED METALS
STREAM FLOW (gpd)
6,088
7,677
22,277
100,853
5,243
17,302
10,782
11,788
14,178
126
TOTAL PLANT
DISCHARGE (gpd)
78,097
66,005
197,012
194,576
61,505
724,389
80,962
86,073
14,178
6,729
% OF
TOTAL FLOW
7.8
11.6
11.3
51.8
8.5
2.4
13.3
13.7
100.
1.8
Average Contribution = 22.2%
                                V-ll

-------
                         TABLE 5-7
           HEXAVALENT CHROMIUM STREAM CONTRIBUTION
               HEXAVALENT CHROMIUM
PLANT ID        STREAM FLOW (gpd)

05050              66,880
06052             692,800
06072               9,492
06090              17,280
06091              71,040
06960              27,636
09025              41,376
12075              85,680
18538             138,038
19068               1,698
20081              17,952
20082              80,506
20083               5,193
20087                 352
21051               8,640
21066              14,547
30050               7,330
30054               1,682
30074              25,954
31050                 603
33024               2,956
33074               5,503
34050                 960
35061              46,400
38051               2,240
38052               9,372
40061              40,553
43003               2,560
44050              11,054
44062              15,772

  Average Contribution = 28.7%
TOTAL PLANT
DISCHARGE (gpd)
135,200
1,107,200
51,788
135,360
162,720
43,076
147,776
721,616
923,011
8,128
23,040
80,506
86,073
86,240
17,280
82,685
565,226
21,840
54,984
4,606
26,723
377,239
36,000
368,000
67,664
14,178
47,925
292,000
113,910
74,418
% OF
TOTAL FLOW
49.5
62.6
18.3
12.8
43.7
64.1
28.0
11.9
14.9
20.8
77.9
100.
6.0
0.4
50.
17.6
1.3
7.7
47.2
13.1
11.0
1.4
2.7
12.6
3.3
66.1
84.6
0.9
9,7
21.2
                                 V-12

-------
                         TABLE 5-8
            CYANIDE BEARING STREAM CONTRIBUTION
PLANT ID
CYANIDE BEARING
STREAM FLOW (gph)
 TOTAL PLANT
EFFLUENT (gph)
  % OF
TOTAL FLOW
02033
04045
05021
06037
06052
06072
06073
06075
06081
06084
06085
06089
06090
06091
06381
09026
11103
12065
15070
19050
20077
20078
20079
20080
20081
20082
20086
20087
21051
21066
30022
31021
33024
33065
33070
33073
35061
36041
36623
38051
1735
6000
833
1000
15900
280
320
1200
4488
733
750
633
8460
4440
900
2257
2000
49
800
435
3000
300
100
553
183
2700
400
3
1080
519
480
2160
657
549
500
433
6200
173
3210
65
44500
6000
4546
6350
69200
5415
2050
5938
6972
2613
3803
1983
8460
10170
6378
7086
5367
26646
2333
2702
23370
1967
591
2542
3008
5414
1800
3348
1080
3440
2040
6668
3336
549
4200
2346
23000
1821
15190
858
3.8
100.
18.3
15.7
23.0
5.2
15.6
20.2
64.4
28.0
19.7
31.9
100.
43.6
14.1
31.8
37.3
0.2
34.2
16.1
12.8
15.2
16.9
21.7
6.1
49.7
22.2
0.1
100.
15.
23.5
32.3
19.7
100.
11.9
18.4
27.0
9.5
21.1
7.5
  Average Contribution =  28.8%
                              V-13

-------
                                    TABLE 5-9
                      SEGREGATED OILY WASTEWATER CONTRIBUTION
PLANT ID
03043
04282
04892
06019
12078
13042
13324
14062
15010
15055
19462
20005
20103
20170
23041
28699
30012
30166
30516
31031
33050
33692
38040
SEGREGATED
OILY WASTE
DISCHARGE (gpd)
2,081
93,967
860
30,800
15,300
6,000
215
14,362
13,000
30,000
2,200
174,990
83,130
82
3,090
190,280
4,845
249
240
286
2,558
68,000
693
TOTAL PLANT
DISCHARGE (gpd)
118,650
567,000
285,200
1,810,000
1,064,900
144,870
223,420
609,700
1,100,000
600,000
250,000
1,500,000
150,000
668,050
900,000
600,000
312,440
11,250
20,000,000
2,160,000
320,000
500,000
117,000
% OF
TOTAL FLOW
1.75
16.6
0.30
1.70
1.44
4.14
0.10
2.36
1.18
5.00
0.88
11.7
55.4
0.01
0.34
31.7
1.55
2.21
0.00
0.01
0.80
13.6
0.59
Average Segregated Oily Waste  Contribution = 6.6%.
                                 V-14

-------
WASTE CHARACTERISTICS FROM METAL FINISHING UNIT OPERATIONS

The waste constituents most commonly found in wastewaters
generated by the forty-four metal finishing unit operations are
described in the following subsections and are summarized in
Table 5-10.  Operations which have been designated zero dischargers
are omitted from this discussion.  Included in each of the unit
operation presentations is a listing of each subcategory to which
the particular operation's wastewater could contribute.

Electroplating - Electroplating baths contain metal salts, acids,
alkalies, and various bath control compounds.  All of these
materials contribute to the wastewater stream either through
part dragout, batch dump, or floor spill.  Electroplating baths
can contain copper, nickel, silver, gold, zinc, cadmium, palla-
dium, platinum, chromium, lead, iron and tin.  In addition to
these metals, common cationic components of plating baths are
ammonia, sodium and potassium.  Anions likely to be present are
borate, cyanide, carbonate, fluoride, fluoborate, phosphates,
chloride, nitrate, sulfate, sulfide, sulfamate and tartrate.

Many plating solutions contain metallic, metallo-organic and
organic additives to induce grain refining, leveling of the
plating surface and deposit brightening.  Arsenic, cobalt,
molybdenum and selenium are used in this way, as are saccharin
and various aldehydes.  These additives are generally present
in a bath at concentrations of less than one percent by volume
or weight.  Table 5-11 presents a selection of plating baths
and their major constituents.  The processes covered under the
electroplating unit operation and the subcategories to which
they contribute wastewater are listed below:

         Common metals - aluminum electroplating, brass electr-
                         plating, bronze electroplating, cadmium
                         electroplating, acid copper, fluoborate
                         copper and copper pyrophosphate electro-
                         plating, iron electroplating, lead
                         electroplating, nickel electroplating,
                         solder electroplating, tin electroplating,
                         zinc electroplating.

         Precious metals - gold electroplating, silver electroplating
                           rhodium electroplating, palladium electro-
                           plating, platinum electroplating, indium
                           electroplating, rutherium electroplating,
                           iridium electroplating, osmium electro-
                           plating.

         Cyanide wastes - cyanide copper plating, cadmium plating,
                          zinc plating, brass plating, precious
                          metals plating.

         Hexavalent chromium wastes - chromium plating.
                              V-15

-------
WASTE
CHARACTERISTICS
           TABLE 5-10
WASTE CHARACTERISTIC DISTRIBUTION

           INORGANICS
ORGANICS
UNIT
OPERATION
1.
2.
3.
4.
5.
6.
7.
8.
9.
f 10.
£ n-
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
Electroplating
Electroless Plating
Anodizing
Conversion Coating
Etching (Chem. Milling)
Cleaning
Machining
Grinding
Polishing
Tumbling
Burnishing
Impact Deformation
Pressure Deformation
Shearing
Heat Treating
Thermal Cutting
Welding
Brazing
Soldering
Flame Spraying
Sand Blasting
Other Abr. Jet Machining
Elec. Discharge Mach.
Electrochemical Mach.
Electron Beam Mach.
Laser Beam Mach.
Plasma Arc Mach.
Ultrasonic Machining
Common Precious Complexed Chromium Zero
Metals Metals Metals (Hexavalent) Cyanide Oils Solvents Discharge
XX XX
XX X X
X X
XX XX
XX X X X
XX X X XXX
X X
X X
XX X
X XXX
XX XX
X X
X X
X X
X XX
X
X
X
X
X
X
X X
X X
X XX
X
X
X
X

-------
                                                                             TABLE 5-10 (Con't)


                                                                     WASTE CHARACTERISTIC DISTRIBUTION
                                            WASTE

                                            CHARACTERISTICS
                                                                                 INORGANICS
                                                                                                                        ORGANICS
<

(-•
-j
UNIT
OPERATION
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
Sintering
Laminating
Hot Dip Coating
Sputtering
Vapor Plating
Thermal Infusion
Salt Bath Descaling
Solvent Degreasing
Paint Stripping
Painting
Electrostatic Painting
Electropainting
Vacuum Metalizing
Assembly
Calibration
Testing
Common Precious
Metals Metals

X
X



X
X
X
X
X
X

X


Complexed Chromium Zero
Metals (Hexavalent) Cyanide Oils Solvents Discharge
X


X
X
X
X
X X
X X
X
X X
X
X
X X
X
X

-------
                        TABLE 5-11
              CONSTITUENTS OF PLATING BATHS
Electroplating Bath

Brass & Bronze:
Cadmium-Cyanide:
Cadmium-Fluoborate:
Copper-Cyanide:
Copper-Fluoborate:
Acid Copper-Sulfate:
Copper Pyrophosphate;
Fluoride Modified
Copper Cyanide:


Chromium:


Chromium with
Fluoride Catalyst:


Gold-Cyanide:
Composition

Copper cyanide
Zinc cyanide
Sodium cyanide
Sodium carbonate
Ammonia
Rochelle salt

Cadmium cyanide
Cadmium oxide
Sodium cyanide
Sodium hydroxide

Cadmium fluoborate
Fluoboric acid
Boric acid
Ammonium fluoborate
Licorice

Copper cyanide
Sodium cyanide
Sodium carbonate
Sodium hydroxide
Rochelle salt

Copper fluoborate
Fluoboric acid

Copper sulfate
Sulfuric acid

Copper pyrophosphate
Potassium hydroxide
Ammonia

Copper cyanide
Potassium cyanide
Potassium fluoride

Chromic acid
Sulfuric acid

Chromic acid
Sulfate
Fluoride

Metallic gold
Potassium cyanide
Sodium phosphate
                             "-18

-------
                        TABLE 5-11 (Con't)
                  CONSTITUENTS OF PLATING BATHS
Electroplating Bath

Iron:
Lead-Fluoborate;
Lead-Tin:
Nickel (Watts):
Nickel-Acid Fluoride;
Black Nickel:
Composition

Ferrous sulfate
Ferrous chloride
Ferrous fluoborate
Calcium chloride
Ammonium chloride
Sodium chloride
Boric acid

Lead fluoborate
Fluoboric acid
Boric acid
Gelatin or glue
Hydroquinone

Lead fluoborate
Tin fluoborate
Boric acid
Fluoboric acid
Glue
Hydroquinone

Nickel sulfate
Nickel chloride
Nickel fluoborate
Boric acid
Nickel sulfate
Nickel chloride
Nickel sulfamate
Boric acid
Phosphoric acid
Phosphorous acid
"Stress-reducing agents'

Hydrofluoric acid
Nickel carbonate
Citric acid
Sodium lauryl sulfate
  (wetting agent)

Nickel ammonium sulfate
Nickel sulfate
Zinc sulfate
Ammonium sulfate
Sodium thiocyanate
                              V-19

-------
                        TABLE 5-11 (Con't)
                  CONSTITUENTS OF PLATING BATHS
Electroplating Bath

Silver:
Acid-Tin:
Stannate-Tin:
Tin-Copper Alloy;
Tin-Nickel Alloy:
Tin-Zinc Alloy:
Acid-Zinc:
Zinc-Cyanide:
Composition

Silver cyanide
Potassium cyanide or
  Sodium cyanide
Potassium carbonate or
  Sodium carbonate
Potassium hydroxide
Potassium nitrate
Carbon disulfide

Tin fluoborate
Fluoboric acid
Boric acid
Stannous sulfate
Sulfuric acid
Cresol sulfonic acid
Beta naphthol
Gelatin

Sodium stannate
Sodium hydroxide
Sodium acetate
Hydrogen peroxide

Copper cyanide
Potassium stannate
Potassium cyanide
Potassium hydroxide
Rochelle salt

Stannous chloride
Nickel chloride
Ammonium fluoride
Ammonium bifluoride
Sodium fluoride
Hydrochloric acid

Potassium stannate
Zinc cyanide
Potassium cyanide
Potassium hydroxide

Zinc sulfate
Ammonium chloride
Aluminum sulfate or
  Sodium acetate
Glucose or
  Licorice

Zinc oxide
Sodium cyanide
Sodium hydroxide
Zinc cyanide
                              V-20

-------
Electroless Plating - Electroless plating  (autocatalytic)  is
most often used on printed circuit boards, as a base plate for
plating on plastics, and as a protective coating on metal  parts.
Copper and nickel are the metals most often plated autocataly-
tically, although iron, cobalt, gold, palladium, and arsenic
can also be plated in this manner.  The components of several
electroless plating baths are listed in Table 5-12.  The
principle components are the metal being deposited, a reducing
agent such as sodium hypophosphite or formaldehyde, and various
complexing (or chelating) agents such as rochelle salt, EDTA,
or sodium citrate.  Bath constituents enter the waste stream by
way of dragout or batch dumping of the process bath.

Immersion plating, which is categorized with electroless plating,
generates waste by basis material dissolution and process  solution
dragout.  Table 5-13 lists the different immersion plating solu-
tions as well as the base material upon which each can be  deposited.
Immersion plating baths are usually simple formulations of metal
salts, alkalies and complexing agents.  The complexing agents are
typically cyanide or ammonia and are used  to raise the deposition
potential of the metal.  Because of the displacement action in-
volved in the immersion plating operation, more basis material ends
up in the waste stream than the metal being deposited.  Electroless
plating wastewaters are contributed to the various subcategories
by the following operations:

       Precious metals - Electroless gold, electroless silver,
                         electroless palladium, immersion  gold,
                         immersion palladium, immersion platinum,
                         immersion rhodium, immersion silver.

       Complexed metals - All electroless  plating operations, all
                          immersion plating operations.

       Cyanide - Electroless gold, electroless arsenic, electroless
                 silver, immersion brass,  immersion silver, immersion
                 tin.

Anodizing - The wastewaters generated by anodizing include the
basis material being anodized (aluminum or magnesium) as well
as the constituents of the processing baths.  Anodizing is done
using solutions of either chromic or sulfuric acid.  In addition,
it is common to dye or color anodized coatings.  A number  of these
dyes contain chromium  (which will be found in wastewaters  when
the dyes are used) and other metals.  Nickel acetate is widely
used to seal anodic coatings and is therefore another potential
pollutant associated with anodizing.  Other complexes and  metals
originating from dyes, coloring solutions  and sealers could
possibly be found in anodizing wastewaters.
                                V-21

-------
                         TABLE 5-12
          CONSTITUENTS OF ELECTROLESS  PLATING  BATHS
Process
Electroless Nickel
Electroless Copper;
Electroless Cobalt-Nickel:
Electroless Gold:
Electroless Gold over Cu,  Ni,  Kovar:
Composition

Nickel chloride
Sodium glycollate
Sodium hypophosphite

    or

Nickel carbonate
Hydrofluoric acid
Citric acid
Ammonium acid fluoride
Sodium hypophosphate
Ammonium hydroxide

Copper nitrate
Sodium bicarbonate
Rochelle salt
Sodium hydroxide
Formaldehyde

    or

Copper sulfate
Sodium carbonate
Rochelle salt
Versene-T
Sodium hydroxide
Formaldehyde

Cobalt chloride
Nickel chloride
Rochelle salt
Ammonium chloride
Sodium hypophosphite

Potassium gold cyanide
Ammonium chloride
Sodium citrate
Sodium hypophosphite

Poatassium gold cyanide
Citric acid
Monopotassium acid phthalate
Tungstic acid
Sodium hydroxide
N,N diethylglycine (Na salt)
                             V-22

-------
                    TABLE  5-12  (CONTINUED)
Process
Electroless Iron:
Electroless Palladium;
Electroless Arsenic:
Electroless Chromium  (acidic):
Electroless Chromium  (alkaline)
Electroless Cobalt:
Electroless Silver:
Composition

Ferrous sulfate
Rochelle salt
Sodium hypophosphite

Tetramine palladium chloride
Disodium EDTA
Ammomium hydroxide
Hydrazine

Zinc sulfate
Arsenic trioxide
Sodium citrate
Sodium cyanide
Sodium hydroxide
Ammonium hydroxide
Sodium hypophosphite

Chromic bromide
Chromic chloride
Potassium oxalate
Sodium acetate
Sodium hypophosphite

Chromic bromide
Chromic iodide
Sodium oxalate
Sodium citrate
Sodium hypophosphite

Cobalt chloride
Sodium citrate
Ammonium chloride
Sodium hypophosphite

Silver cyanide
Sodium cyanide
Sodium hydroxide
Dimethylamine borane
Thiourea
                            V-23

-------
                         TABLE  5-13
            CONSTITUENTS OF IMMERSION PLATING BATHS
Process

Immersion Plating -

               Copper on Steel:


               Copper on Zinc:



               Gold on Copper Alloys:



               Gold on Iron & Steel:
               Lead on Copper Alloys
               and on Zinc:
               Lead on Steel:
               Nickel on Aluminum;
               Nickel on Copper
               Alloys:
               Nickel on Steel:
               Nickel on Zinc:
               Palladium on Copper
               Alloys:
               Platinum on Copper
               Alloys:

               Rhodium on Copper
               Alloys:
Composition
Copper sulfate
Sulfuric acid

Copper sulfate
Tartaric acid
Ammonia

Potassium gold cyanide
Sodium cyanide
Sodium carbonate

Denatured alcohol
Gold chloride

Lead monoxide
Sodium cyanide
Sodium hydroxide

Lead nitrate
Sodium cyanide
Sodium hydroxide

Nickel sulfate
Ammonium chloride

Nickel sulfate
Nickel ammonium sulfate
Sodium thiosulfate

Nickel chloride
Boric acid

Nickel sulfate
Sodium chloride
Sodium carbonate

Palladium chloride
Hydrochloric acid
Ammonia  (sealant)

Platinum chloride
Hydrochloric acid

Rhodium  chloride
Hydrochloric acid
                            V-24

-------
                          TABLE 5-13(Con1t)
Process

Immersion Plating -

               Arsenic on Aluminum;
               Arsenic on Copper
               Alloys:
               Arsenic on Steel:
               .Brass on Aluminum:
               Brass on Steel:
               Cadmium on Aluminum;
               Cadmium on Copper
               Alloys:

               Cadmium on Steel:
               Copper on Aluminum;
               Ruthenium on Copper
               Alloys:

               Silver on Copper
               Alloys:
Composition
White arsenic
Sodium carbonate

White arsenic
Ferric chloride
Muriatic acid

White arsenic
Muriatic acid

Zinc oxide
Sodium hydroxide
Copper cyanide
Sodium cyanide
Lead carbonate

Stannous sulfate
Copper sulfate
Sulfuric acid

Cadmium sulfate
Hydrofluoric acid

Cadmium oxide
Sodium cyanide

Cadmium oxide
Sodium hydroxide

Copper sulfate
Ammonia
Potassium cyanide

Copper sulfate
Hydrofluoric acid

Copper sulfate
Ethylene diamine

Ruthenium chloride
Hydrochloric acid

Silver cyanide
Sodium cyanide
Silver nitrate
Ammonia
Sodium thiosulfate
                               V-25

-------
                        TABLE 5-13  (CONTINUED)
Process

Immersion Plating -

               Silver on Zinc:


               Tin on Aluminum:

               Tin on Copper
               Alloys:


               Tin on Steel:
               Tin on  Zinc:
Composition
Silver cyanide
Potassium

Sodium stannate

Tin chloride
Sodium cyanide
Sodium hydroxide

Stannous sulfate
Sulfuric acid
Cream of tartar
Tin chloride

Tin chloride
                           V-26

-------
Wastewaters are generated by the following anodizing operations:

      Common metals - Sulfuric acid anodizing/ phosphoric acid
                      anodizing, oxalic acid anodizing, dyeing,
                      nickel acetate sealing.

      Cyanide - Ferrocyanide pigment impregnation

      Hexavalent chromium - Chromic acid anodizing, dichromate
                            sealing.

Conversion Coating - Several types of conversion coating operations
such as phosphating, chromating, coloring, and passivating con-
tribute pollutants to raw waste streams.  These pollutants enter
the waste stream through rinsing after coating operations and
batch dumping of process baths.  Coating process baths usually
contain metal salts, acids, bases, and dissolved basis materials
and various additives.

The phosphates of zinc, iron, manganese and calcium are most often
used for phosphate coatings.  Strontium and cadmium phosphates
are used in some baths, and the elements aluminum, chromium,
fluorine, boron and silicon are also common bath constituents.
Phosphoric acid is used as the solvent in phosphating solutions.

Coloring can be done with a large variety of solutions.  Several
metals may be contributed to the waste stream by coloring opera-
tions, among them copper, nickel, lead, iron, zinc and arsenic.
Passivation can be done in a nitric acid solution (for stainless
steel) or a caustic solution (for copper).  In both cases,
dissolved basis materials enter the wastewater.

There are a number of conversion coating processes which utilize
chromium-containing solutions.  These include chromating, black
oxidizing and sealing rinses.  Chromating baths are usually
proprietary solutions which contain concentrated chromic acid
and active organic or inorganic compounds (even cyanide in some
instances).  Both hexavalent and trivalent chromium will be
found in chromate conversion coating baths and in the rinses
associated with them.  Black oxidizing is done in solutions
containing dichromate while sealing rinses used extensively
following phosphating are usually made up of very dilute chromic
acid.  Any of these conversion coating operations will also
contribute small amounts of basis material to their respective
wastewater streams.

The wastewater contribution of conversion coating operation is
as follows:

        Common metals - Phosphating, nitric acid or caustic
                        passivation, coloring.
                              V-27

-------
        Precious metals - Chromating of silver

        Cyanide - Some chromating processes

        Hexavalent chromium - Chromating, dichromate passivation,
                              chromic acid sealing of phosphate
                              coatings.


Etching - Wastewater is produced in this unit operation by
etching, chemical milling, bright dipping and related operations.
As demonstrated by the list of etching solutions in Table 5-14,
the majority of etching solutions are acidic while sodium
hydroxide is used quite frequently as a caustic etch on aluminum.
The constituents in the waste stream produced by etching opera-
tions are predominatly dissolved basis materials.  Among the
basis materials commonly etched are stainless steel, aluminum
and copper.  In addition to these materials, metals such as zinc
and cadmium may appear in the waste stream due to bright dipping
of these metals.

Certain etching baths contain concentrated chromic acid and are
usually employed prior to plating steps.  Chromic acid etches
are used extensively on plastics prior to electroless plating of
copper or nickel.  These etching solutions and their associated
rinses can contain hexavalent and trivalent chromium, small
amounts of organic compounds (when used for etching plastics)
and metals which originate in the basis material being etched.
Chromic acid (in conjunction with other acids) is also used for
the bright dipping of copper and copper alloys as well as zinc
and cadmium plated parts.

An increasing number of etching solutions incorporate ammonia
compounds.  Ammonium hydroxide and ammonium chloride are the
most common constituents of these baths.  The ammonia contributed
by these compounds acts as a metal-complexing agent in solution.
Dumps of these baths or discharge of rinses following ammoniacal
etches will therefore contain complexed wastes.  These etchants
are most widely used in the manufacture of printed circuit
boards and their associated discharges can include complexed
copper as well as various organic compounds (from the epoxy
board and from etch resist formulations).

Cyanides are not generally used as constituents in etching
baths.  However, at least one bright dipping solution (for silver)
does contain a mixture of sodium cyanide and hydrogen peroxide.
The use of this particular bath will yield wastewater containing
the above-mentioned constituents as well as silver.
                               V-28

-------
                          TABLE 5-14
          CONSTITUENTS OF PROCESS BATHS USED IN ETCHING
Process
Chemical Etching -
               Ferric chloride
               solns:
               Ammonium persulfate
               solns:
               Cupric chloride
               solns:
               Chromic-sulfuric
               acid solns:
Chemical Milling:
Electrochemical Milling -
               on stee-l, cobalt,
               copper, chromium:
               for tungsten &
               molybdenum alloys:
Composition
Ferric chloride
Hydrochloric acid
Base material

Ammonium persulfate
Mercuric chloride
Sulfuric acid
Ammonium chloride
Sodium chloride
Copper
Base material

Cupric chloride
Hydrochloric acid
Sodium chloride
Ammonium chloride
Base material

Chromic acid
Sodium sulfate
Sulfuric acid         ^
Copper
Base material

Nitric acid
Chromic acid
Hydrochloric acid
Base metal
 (Sodium hydroxide used
  on aluminum)
Sodium chloride
Sodium nitrate
Base metal


Sodium hydroxide
Sodium chloride
Base metal
                                 V-29

-------
                      TABLE 5-14 (CONTINUED)
Process
Bright Dip -
               for Copper:
               for Aluminum:
               also for Nickel:
               for Zinc and
               Cadmium:

               for Silver:
Composition
Nitric acid
Acetic acid
Phosphoric acid
Hydrochloric acid

Phosphoric acid
Nitric acid
Glacial acetic acid

Phosphoric acid
Sulfuric acid
Nitric acid
Phosphoric acid
Nitric acid
Titanium chloride

Chromium acid
Sulfuric acid

Sodium cyanide
Hydrogen peroxide
                             V-30

-------
Etching operations contribute wastewater to the various sub-
categories in the following manner:

      Common metals - Etching, bright dipping and chemical milling
                      of common metals basis materials with
                      solutions such as ferric chloride, cupric
                      chloride, nitric acid, hydrochloric acid,
                      phosphic acid, sulfuric acid, hydrofluoric
                      acid; stripping of common metal platings.

      Precious metals - Any etching or bright dipping of precious
                        metals stripping of precious metal platings,

      Complexed metals - Etching with ammoniated solutions such as
                         ammonium hydroxide and ammonium chloride.

      Cyanide - Certain bright dipping operations; cyanide
                stripping operations.

      Hexavalent chromium - Etching, bright dipping, or chemical
                            milling with solutions containing
                            chromic acid; stripping with chromic
                            acid or stripping of chromium platings.

Cleaning - Cleaning operations are used throughout the Metal
Finishing Category and provide the bulk of the wastewater generated
by the industry-  The purpose of cleaning is to remove the bulk
of all of the soils (oils and dirt) prior to phosphating, electro-
plating, painting, pre and post penetrant inspection, burnishing
and polishing, or after any other operation that produces an oil
bearing part.  Cleaning is often a necessary precedent for several
of the metal finishing operations.  This cleaning does not include
solvent cleaning which in itself is a separate unit operation.

Alkaline cleaning solutions usually contain one or more of the
following chemicals:  sodium hydroxide, sodium carbonate, sodium
metasilicate, sodium phosphate (di- or trisodium), sodium silicate,
sodium tetraphosphate, and a wetting agent.  The specific content
of cleaners varies with the type of soil being removed.  For
example, compositions for cleaning steel are more alkaline and
active than those for cleaning brass, zinc die castings, and
aluminum.  Wastewaters from cleaning operations contain not only
the chemicals found in the alkaline cleaners but also soaps from
the saponification of greases left on the surface by polishing
and buffing operations.  Some oils and greases are not saponified
but are, nevertheless, emulsified.  The raw wastes from cleaning
show up in rinse waters, spills and dumps of concentrated solutions,
                              V-31

-------
The concentrations of dissolved basis metals in rinses  following
alkaline cleaning are usually small relative to acid dip  rinses.

Organic chelating agents are utilized in some alkaline  cleaning
solutions in order to help soften the water.  Hardness  constituents
such as calcium and magnesium salts are chelated as inert soluble
complexes.  This facilitates their removal from the surface of
a part and prevents the formation of insoluble scums (from
calcium and magnesium soaps).  Therefore, some alkaline cleaning
baths and their subsequent rinses contain complexed metals,
phosphates in various forms and organic compounds including oils
and greases.

Solutions for pickling or acid cleaning usually contain one or
more of the following:  hydrochloric acid (most common),  sulfuric
acid, nitric acid, chromic acid, fluoboric acid, and phosphoric
acid.  The solution compositions vary according to the  nature of
the basis metals and the type of tarnish or scale to be removed.
These acid solutions accumulate appreciable amounts of  metal as
a result of dissolution of metal from workpieces or uncoated areas
of plating racks that are recycled repeatedly through cleaning,
acid treating, and electroplating baths.

As a result, the baths usually have a relatively short  life, and
when they are dumped and replaced, large amounts of chemicals must
be treated or reclaimed.  These chemicals also enter the  waste
stream by way of dragout from the acid solutions into rinse waters.

The amount of waste contributed by acid cleaners and alkaline
cleaners varies appreciably from one facility to another  depending
on the substrate material, the formulation of the solution used
for cleaning or activating the material, the solution temperature,
the cycle time, and other factors.  The initial condition  of the
substrate material affects the amount of waste generated  during
treatment prior to finishing.  A dense, scale-free copper  alloy
part can be easily prepared for finishing by using a mild  hydro-
chloric acid solution that dissolves little or no copper,  whereas
products with a heavy scale require stronger and hotter solutions
and longer treating periods for ensuring the complete removal of
any oxide prior to finishing.

Electrocleaners are basically heavy duty alkaline types that are
employed with an electrical current.  They are designed both for
soil removal and metal activation.  A dilute mineral acid  dip
usually follows the final cleaners to neutralize the alkaline film
on the metal surface.

Emulsion cleaning removes soils from the surface of metals by
the use of common organic solvents (e.g. kerosene, mineral oil,
glycols, and benzene) dispersed in an aqueous medium with  the
                              V-32

-------
aid of an emulsifying agent.  Parts which have been emulsion
cleaned are not normally rinsed following the cleaning operation.
Wastes come from leaks and floor spills and can contain removed
soils plus any of the cleaner constituents listed above.

Phosphates are used in some cleaners and function as water
softeners, rinsing aids, soil suspending agents, and detergency
boosters.  Common cleaners include trisodium phosphate, sodium
tripolyphosphate, tetrasodium and tetrapotassium pyrophosphates,
and "glassy" phosphates such as sodium hexametaphosphate.

Biphase cleaning involves two immiscible liquid phases.  One phase
consists of water plus water soluble wetting agents, and may also
include inorganic salts and emulsified oil.  The other phase
usually is a layer of some suitable organic solvent or solvents.

In general, cleaning baths and their associated rinses can
contain oils, greases, grit, base metals, complexing agents,
cyanides, acids, alkalies and miscellaneous additives.  Cleaning
operations contribute to the raw waste subcategories in the
following way:

      Common metals - Most acid and alkaline cleaning operations.

      Precious metals - Cleaning operations done on a precious
                        metal basis material.

      Complexed metals - Cleaning operations done with heavily
                         chelated alkaline cleaners.

      Hexavalent chromium - Cleaning done with chromated cleaners.

      Cyanide - Cleaning done with cyanide cleaners.

      Oily Waste - Cleaning of very oily parts.

      Solvent - Solvent wiping, emulsion cleaning, vapor degreasing,

Machining - Machining operations performed in the Metal Finishing
Category incorporate the use of natural and synthetic oils for
cooling and lubrication.  Spills and leakage onto floor areas may
be washed away with water and contribute oil/water emulsions to
wastewater streams.  Chip removal techniques produce large amounts
of metal solids and clinging oils.  Chip storage areas may include
oil recovery facilities if the production level warrants them.   If
properly contained, these oily wastes will not normally enter
wastewater streams.  Any wastewaters which are generated belong
to the common metals and oily waste subcategories.

Grinding - Natural and synthetic oils are used in many grinding
operations.  Soluble oil emulsions and other fluids are used for
cooling and lubrication, in a similar manner to that for machin-
                               V-33

-------
ing.  Some of these fluids are highly chlorinated and sulfochlor-
inated water soluble oils that contain wetting agents and rust
inhibitors.  Grinding system sumps contain ground metallic dust
(or swarf) which is an oily sludge requiring periodic removal.
This sludge does not mix with wastewater; however, grinding area
spills and leaks may be washed into wastewater streams.  They
can contain any of the oily and additive constituents mentioned
above.  These wastes could contribute to the common metals, oily
waste and solvent subcategories.

Polishing - The wastes generated include polishing and buffing
compounds, greases, metallic soaps, wafers, mineral oils, and
dispersing agents.  Greases with stearic acid addition, hydro-
generated glycerides, and petroleum waxes are also used in
these operations.  Abrasives and fine metal particles accumulate
and must be periodically removed.  Area cleaning and washdown can
produce wastes that enter wastewater streams.  They would belong
to the common metals and oily waste subcategories.

Barrel Finishing - Abrasives, cleaners, soaps, anti-rust agents,
emulsified oils, and water are used in barrel finishing (tumbling)
operations.  Caustic and alkaline cleaners are also used.  Chemical
solutions used in barrel finishing include maleic acid, tartaric
acid, citric acid, sodium cyanide and sodium dichromate.  Wastes
from tumbling consist of dilute oils, process chemicals, fine
clays, scale, and abrasive grit.  Wastewater is generated by
rinsing of parts following the finishing operation and by
periodic dumping of process solutions.  Contributions to the
common metals, hexavalent chromium, cyanide and oily waste sub-
categories could be made by this operation, depending upon the
chemical solutions employed.

Burnishing - Lubricants and soap solutions are used to cool tools
used in burnishing operations.  Because burnishing provides a
smoother surface, light spindle oil or rich soluble oil is usually
used.  Wastes may come from spills, leaks, process solution dumps
and post-finish rinsing.  The wastes could contribute to the
common metals, precious metals and oily waste subcategories, depending
upon the basis material finished.

Impact Deformation, Pressure Deformation, and Shearing - Natural
and synthetic oils, light greases, and pigmented lubricants are
used in deformation and shearing operations.  Pigmented lubricants
include:  whiting, lithapone, mica, zinc oxide, molybdenum
disulfide, bentonite, flour, graphite, white lead, and soap-like
materials.  The presses commonly used for these operations incorporate
hydraulic lines and incur fluid leakage that contribute oily waste.
Spills and leaks in work areas may be cleaned with water and
combined with other wastewater streams.

Wastes from these operations would belong to the common metals
and oily waste subcategories.
                             V-34

-------
Heat Treating - Quenching oils are of three general types: con-
ventional, fast, and water/oil emulsions (10-90% oil).  A conventional
oil contains no additives that will alter cooling characteristics.
Fast quenching oils are blends which may contain specially developed
proprietary additives such as nickel-zinc dithiophosphate.  The
wastes generated will contain the solution constituents as well as
various scales, oxides and oils.  Wastewater is generated through
rinses, bath discharges (including batch dumps), spills and leaks.
Included among the solutions used are:

     Brine solutions (used in quenching) which can contribute
     sodium chloride, calcium chloride, sodium hydroxide,
     sodium carbonate, hydrochloric acid and sulfuric acid to
     waste streams.

     Water and water-based solutions (for quenching and rinsing)
     which may contain dissolved salts, soaps, alcohols, oils,
     emulsifiers, slimes and algae.

     Cyaniding (liquid carburizing and carbonitriding) solutions
     for heat treating containing sodium cyanide, inert salts
     (sodium carbonate and sodium chloride), detergents, rust
     preventatives, carbon, alkali carbonate, nitrogen, carbon
     monoxide, carbon dioxide, cyanide, cyanate and oils  (from
     subsequent quenching).

     High temperature baths containing sodium cyanide, potassium
     chloride, sodium chloride, sodium carbonate, calcium and
     strontium chlorides, manganese dioxide, boron oxide, sodium
     fluoride and silicon carbide.

     Unalloyed molten lead used for heat treating steel.

Most heat treating operations contribute wastewater to the common
metals or oily wastes subcategory.  Cyaniding type operations
contribute wastewaters to the cyanide waste subcategory and the
oily waste subcategory.

Thermal Cutting - Water may be used for rinsing or cooling of
parts and equipment following this operation.  Wastewaters
produced would contribute to the common metals and oily waste
subcategories.

Welding, Brazing, Soldering, Flame Spraying - These operations
are normally not wastewater producers.  However, each of them can
can be followed by quenching, cooling or annealing in a solution
of water or emulsified oils.  When this is done, wastes produced
can belong to the common metals subcategory.
                              V-35

-------
Other Abrasive Jet Machining - Abrasive slurries in alkaline or
emulsified oil solutions and abrasives in air, nitrogen, or CO2
are used.  Aluminum oxide, silicon carbide, dolomite, calcium
magnesium carbonate, sodium bicarbonate and glass beads are common
abrasives used in this operation.  Wastewater can be produced
through solution dumps, spills, leaks or washdowns of work areas
and contributes to the common metals and oily waste subcategories.

Electrical Discharge Machining - Dielectric fluids are used in
this operation.  Common fluids include:  hydrocarbon-petroleum
oils, kerosene, silicone oils, deionized water, polar liquids, and
aqueous ethylene glycol solutions.  Rinsing of machined parts and
work area cleanups can generate wastewaters which also contain base
materials.  These wastewaters contribute to the common metals and
oily waste subcategories.

Electrochemical Machining - In addition to standard chemical
formulations, inorganic and organic solvents are sometimes used
as electrolytes for electrochemical machining.  Solvents used
include water, ammonia, hydrocyanic acid, sulfur dioxide, acetone,
benzene, ethanol, diethyl ether, methanol and pyridine.  Any of
the constituents listed as well as the basis material being
machined can enter waste streams via rinse discharges, bath
dumps and floor spills.  Generated wastes can belong to the common
metals, cyanide and solvent subcategories, depending upon the
solvent used.

Laminating - Water is not often used by this unit operation.
However, occasional rinsing or cooling may occur in conjunction
with laminating.  The waste generated could contribute to the
common metals and oily waste subcategories.

Hot Dip Coating - Hot dipping involves the immersion of metal
parts in molten metal.  The molten metal coats the part and an
alloy is formed at the interface of the two metals.  Water is used
for rinses following precleaning and sometimes for quenching after
coating.  Aluminum, zinc, lead and tin are the metals most commonly
used.  Hot zinc coating (galvanizing) is probably used more
extensively than any others.  Galvanizing (as well as the other
coatings) is done mainly for corrosion protection; in a few
instances, hot dip coatings are also used for decorative purposes.
Most hot dip coatings require fluxing.  In galvanizing, a zinc
ammonium chloride flux is normally used prior to the actual
coating step.  These wastewaters can contribute to the common
metals subcategory.

Salt Bath Descaling - These baths contain molten salts, caustic
soda, sodium hydride and chemical additives.  They are designed
to remove rust,  scale and resolidified glass.  These contaminants
(and a small amount of base material and oils) enter wastewater
                              V-36

-------
streams through rinsing, spills, leaks, batch dumps of process
solutions and improper handling of sludge produced by the process.
Wastewaters produced by salt bath descaling contribute to the
common metals and oily waste subcategories.

Solvent Degreasing - Solvent degreasing uses organic solvents
such as aliphatic petroleums (eg-kerosene, naptha), aromatics
(eg-benzene, toluene), oxygenated hydrocarbons  (eg-ketones, alcohol,
ether), halogenated hydrocarbons (1,1,1-trichloroethane, trichloro-
ethylene, methylene chloride), and combinations of these classes of
solvents.  The degreasing equipment,  sumps, and stills contain
spent solvents and sludges along with removed oils, greases, and
metallic particles.  These pollutants can enter wastewater streams
and contribute to the solvent subcategory.

Paint Stripping - The stripping of paint films  from rejected parts,
hooks, hangers, masks, and other conveyor equipment is included
in this operation.  All the stripping wastes can contain any of
the constituents of the paint being removed, as well as a small
amount of the basis material beneath  the paint  and the constituents
of the stripping solution.  Stripping solutions may contain caustic
soda, wetting agents, detergents, emulsifiers,  foam soaps, alcohol,
amines, ammonia or solvents.  Solvents used include chlorinated
solvents (such as methylene chloride) and highly polar solvents
(such as acetone, methyl ethyl, ketone, benzene and toluene).
Other solvents employed in paint stripping operations include
carbon tetrachloride, trichloroethylene, and orthodichlorobenzene.
Wastes are primarily generated by rinsing and can also contain
small amounts of emulsified oils.  Spills, leaks, and solution
dumps can also contribute to wastewater streams.  Wastes produced
belong to the common metals and oily  waste subcategories.

Painting, Electropainting, Electrostatic Painting - The sources of
wastewater associated with industrial painting  processes include
scrubbing water dumps, discharge of ultrafilter permeate and dis-
charge of rinse waters.  Scrubbing (water curtain) discharges vary
widely in frequency of occurrence, from once a  week up to once
every six to twelve months.  A dump schedule of once a month is
not unusual for painters using water  curtains.  These wastewater
dumps may contain any of the common paint ingredients (which
often involve common metals) such as  solvents,  pigments, resins
and other additives.  Dumps are usually necessitated by buildups
Discharges of ultrafilter permeate can occur in connection with
electrodeposition paint systems (ultrafiltration is used to remove
impurities from the paint bath).  Such discharges would contain
impurities from the spent bath.  However, the ultrafilter permeate
is most commonly used as a water source for rinses immediately
following the electrodeposition process, while  the UF concentrate
is returned to the painting bath.  The rinse water in this type of
system would eventually be discharged to a waste stream and would
                                V-37

-------
contain paint and impurities.

In the dip coating process, wastewaters containing paint pigments
and solvents are generated by selective spray rinsing following
the paint bath. "Electrodeposition rinses generate wastewaters
and are described above.  Rinses following autodeposition are
normally discharged to waste streams and commonly contain chromium
in addition to paint constituents.  Wastewaters from these unit
operations can contribute to the common metals, hexavalent chromium
and solvent subcategories.

Testing - Fuels, lubricating oils, and hydraulic fluids are commonly
used in non-destructive performance testing for many products such
as engines, valves, controls, and pressure vessels.  Oily pene-
trants are used in dye-penetrant inspection and testing operations.
Common penetrants include water, kerosene, ethylene glycol, neutral
oil, SAE 10W or SAE 40W oils, water-washable penetrants, color-
contrast penetrants, and emulsifiers.  Leak testing, final washing
(automobiles, etc) and test area washdowns enter waste streams
and may contain oils and fluids used at testing stations.  These
wastewaters contribute to the oily waste subcategory.
                              V-38

-------
CHARACTERISTICS OF SUBCATEGORY WASTE STREAMS

The waste effluent schematic in Figure 5-2 is applicable to raw
waste streams generated by operations within the Metal Finishing
Category.  In some cases a waste stream will contain pollutants
belonging to more than one subcategory.  When this occurs, it  is
expected that the waste stream will receive the appropriate
specialized treatment prior to joining other streams and receiving
treatment for metals removal.  For example, a waste stream from a
copper cyanide electroplating operation must receive treatment for
cyanide destruction before passing on to metals removal.  An
oil-bearing stream often contains common metals; such streams must
pass through oil removal before going to metals removal.  Selection
of pollutant parameters for regulation is covered in Section VI.
Specific details of appropriate waste treatment techniques are
discussed in Section VII.

In order to characterize the waste streams in each subcategory,
raw waste data were gathered from the sampling visits.  Discrete
samples of raw wastes were taken for each subcategory and analysis
was done as explained previously in this section.  The limits of
detection for the parameters analyzed are listed in Table 5-15.
The results of these analyses were compiled and are presented  in
Tables 5-16 through 5-21.

For each raw waste subcategory there is a table which quantifies
the parameters found within that subcategory.  The tables displaying
the raw waste statistics for each subcategory have seven columns
of numbers which are described as follows:

          Column 1 - Minimum detected concentrations found in the
          analysis of each appropriate waste stream.
          Column 2 - Maximum concentrations found in the
          analysis of each appropriate waste stream.
          Column 3 - Mean concentrations calculated from
          the results of the analysis of each appropriate
          waste stream.
          Column 4 - Median concentrations selected by
          ranking appropriate waste stream concentration
          values.
          Column 5 - # of pts represents the number of
          streams having a measurable value for the para-
          meter.
          Column 6 - # of zeros is the number of times that
          a parameter is not detected.  Zeros are not used
          in the generation of statistics to avoid lowering
          the mean, median, and flow proportioned average
          concentrations to unrepresentative low values.
          However, certain zero values were used.  For example,
          if a total cyanide or total chromium reading is a
          positive number, a corresponding zero value for
          amenable cyanide or hexavalent chromium would be
          counted in the statistics generation.
                                V-39

-------
                        Waste Treatment
                        (If Applicable)


                            Treated
                            Affluent
£>
O


cha
ste
Elu«

nt
e)










rge ,
ra
:nt)


».

Oily Waste
Removal
	 	

<



>v






Manufacturing Facility
Raw Waste Sources
j
(


>B (

j Chromium {
11
Reduction j
	 	 !










^


>c <
Common
Metals \_

>D (
1
\ Cyanide j
! Destruction 1
L 	 	 1

<



» 1


Without Cyanide

JE (

Solvents
i

)F

1 Complexed 1 Precious ,
Metals ! Metals
Removal 1 j Recovery
1 	 . 	 1 1 	 . 	 . 	 1
K
"O
1 <
P^


^^^ —

)G Raw Waste
(Common Metals)
I
9
)x <£y
i
i
j
1
i
I
I






I 	 I








Hauled Or
Reclaimed



|   Metals
I   Removal
                                                                                                                   Hauled Or
                                                                                                                   Reclaimed
                                                                                 Treated
                                                                                 Effluent
                                                                      Final Treated
                                                                         Effluent
                                                                                                                 Stream l/Dcations

                                                                                                                 Normal  Route
                                                                                                        	 Optional  Route


                                                                                         Note: Discharge from precious metals recovery may be
                                                                                               hauled in alternative ways, depending on the
                                                                                               recovery method  in use.
                                                                               FIGURE  5-2

                                                                        WASTE EFFLUENT SCHEMATIC

-------
      TABLE 5-15
MINIMUM DETECTABLE LIMITS
Parameter
1. Aciiuplntiin*
2. Acrolim
1 Acrrtommlt
4. Binitnt
5. Btnzidin*
8. Carbon Titracftlorida (TtfracMoromtTTiantt
7. Oilorobtmtnt
. L 1.2.4-TrichlBrobertztna
1 Mtzicfilorobiiuini
10. 1.2-Oichlnroetnint
11. 1.1.1-Tricftloroctftini
12. Htiaciilorottfian*
11 1,1-Oicfilorottnant
14, 1,1.2-Tncnlarattnana
IS. 1,1.2,2'Tatracftloroatfitm
16. Chloroimini
17. BijiChloram«tn»il Ether
18. Bu/2-ChiorQitmrn ciltir
19. 2-Chlor3etfti( Vm»l El.ttr iMiiid)
20. 2-Caioranaonuiai«nt
21. 2.4,6-TncmofOoninoi
22. Paractiioromtta Creiol
21 Chloroform (Tricnlorornetninci
24. 2-Chlareontrtai
25. 1.2-Dicr.!3rcotnzini
2B. 1.3-Dicfitcroeinzane
27. 1,4-Oic.iloraeenzen*
28. 13'-OicMoro;«nzidine
29- 1.1-0ichlarettn»lent
1 30. 1.2-Triin-OicnlaroftHTttM
31. 2.A-Oichloroornnol
32. 1.2-Dicmaropracana
33. 1.2-Oic.-.iercoreooi>, etncf
41 8m2-CJila/0(ihorri Mttnan*
V.IWTNOT
Otiirrablt ;
Umt mf/t

0.1
0.1
0.001 „
0,01 to 0.001
aooi
0.001
0.01 to 0.001
0.01 to 0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.01 to 0.001
0.01 to u.uwl
0.01 to 0.001
0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to O.OS1
0.001
0.001
0.01 to 0.001
0.001
0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.001
0.01 to 0.001
0.01 to 0.001
0.01 to O.C01
0.01 to 0.001
0.01 to 0.001
1

Parameter
4<4. HtttrrttKt CMondt (OitWorem«rtuntt
49. M«th>, Chlonda iC.V-rqrmuuntt
4C. Mttrtri Bromot iSromoffltmanti
47. Brameiorm iTnoromomiihanti
48, Oichiaroaromamatttant
49. Tricftlorgrluaramainana
50- Dicnlarediliuoramiinant
51. Chtarad:bramcmttltan«
52. HaiacRlarobuiaaicna
SI HtijcrlonjcTciaatntiount
54. Iteonoront
55. NaD^ntna
56. Nrtreoenztnt
57. 2-N.un=nenoi
SB. 4-Nitropatnol
S3. 2,4-OiRitroontnoi
80. 4.5-Oinnro-O-C/nol
81. N-Mitr:saaimtTrmarmna
82. N-'irtTasoCiafierrrummt
61 M-hiiraioai-t-Proavommt
64. Ptntacftlorasrtemil
SS. Ptisrsl
86. 8a(2-E-jnhem) Phtniitu
67. 3urfi Senrri Phthaiait
68. Oi-N-3urrl PMhalate
S3. Di-N-Ocrrl Phinaiata
70. Oittlni Phtnalata
1 71. Oimtthrl Phniiait
: 72. 1.2-Bcnzamnractnt 'Btnzoiai Anttiraeinti
71 Sinzo !a| Pyrrnt i3.4-8citzo-Prrt'"l
74. 14-Bcntotluorintntnt 3*nio ibl Fiuotir.tn«n«i
75. 11.12-8tnzoriuoramnin« (Bcnzo iki Fiuoranintnti






71. Chmtnt
77. Aeanaorttirritna
78. Antfiraeant
79. 1.12-Banzeotrmnt iBtnio ighn-Perrianai
80. Fluorini
81. Phananrnrtne
£5,
0.001
' 0.001
0.001
0.001
aooi :
0.001 ,
0,001
0.001 ;
0.01 to o.aoi i
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001 i
0.01 to 0.001
0,01 to 0.001
0.01 to 0.001
101 to 0.001
0.01 to 0.001
0,01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 '.g 0.001
0.01 to 0.001
0,01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001
0.01 to 0.001 i
0.01 to 0.001 '
0.01 to 0.001 i
0.01 to 0.001 •
0.01 to 0.001 .
82. 1.15.6-Oiaentatftractni lOibtnzo ia.nl Anrtir*cfnti| 0.01 to 0301 i
81 Indeno |1.Z3-cdl Pyrano 11.3-0-PhtnTltflt P^rtn.i
84. Prrtni
15. Tttrac.iloroitn«imt
18. Tota.n.
0.31 to 0.001
0.01 to 0.001
0.001
0.001
           V-41

-------
TABLE  5-15  (continued)
Parameter
17. Tri«WflroetM«rt»
IS. VirrH CMande iChloratrrnhcntl
83. Aldnn
SO. Onldrin
91. Chlareini (T tunnies!
.Mimri tnd Wtfatolitii)
32. 4.4--OOT
91 4.4-.QDE .'oo'-OOX)
94. 44'-0:0 •e.s'-TuEi
95. Alohi-Endoiuiun
36. Scti-Eneai^itin
97. Encoiuifin Suiint
98. Enonn
99. Enann Aidfftvdt
100. Ht:ticnior
101. Hiptic.llar Epoiiat
(BHC-HtiicnlorocTdohturnl
102. Alem-SHC
101 Ben-5HC
104. C^mmt-ehC iLnaintl
105. Dtiu-SHC
lPCB-?anrcmonnjtra aiohtimti
105. PCa-UiZ iiaeiist 1242)
107. BC3-12!4 Aroc-ioi !2£4)
108. PCS-U21 liroenlor 121)
103. PC3-1332 ,AroK:ar 1232)
110. PCS-1243 i.Arjc^of !2*Si
111. PC8-I250 ,Arocnlar 12501
j 112. PC3-1316 lAfoeWor 1016)
113. Toiioninc
114. AntimonT
IIS. Arsenic
IIS. Ajbtttn
117. Btnllium
118. Ciamium
119. Chromium
120. Cacpir
121. Ctinidt
122. Lud
121 Miftun
124 Niotl
125. Stitnium
125. S.i.tr
127. Thi.iium
12S ZM-.C
129. 2.3.7. S-TitrieniofoOiSinji-
P-Oioim fTCOOl
Htrnmuffl
0«t*ettfti«
\jput m^/l
0.001 i
0.001
O.C01
0.001
0.001
1
0.001
O.C01
0.001
a. QOI
0.001
0.001
0.001
0.01 to 0001
Q.OQ1
0.001
0.001
0.001
0.001
aooi
0.001
0.001
3.001
0.001
0.001
0.301
0.001
0.001
0.10/0.0001
0.01/0.0001
—
0.001
0.002 i
o.oos
0.005
0.01 to O.C35
0.02
0.0001
0.305
0.20-0.0:01
o.coi'0.cc:i
0.04 0 0001
0.001
0.01 ta a. ooi
                               Parameter
  (mg/1)
                         Iron
                         IcIUtum
                         Otanlmn
                         Plat I mm
                         Tin
                                   Chicinturn
                         ltH>;>|j|ioriiu (total)
                         Hn.jrt.te
                         Cyanide ftjoonable to Oh lor I nation
                         Tula I Hlionuls
                         Ol I  ami Hi ease
O.OOS



0.01
                                                        "Or
                                                         0.08
                                                         0.006
                                                         0705
                                                         0.004
                                                         0.05
                                                         0.00
                                                         0.005
                                                         0.01
0.1



0.005
                                                         0.005
b.O to  1.0




5.0 to  1.0
          V-42

-------
Common Metals Subcategory - Pollutant parameters found  in  the
common metals subcategory raw waste stream from sampled plants are
shown in Table 5-16.  The major constituents shown are  parameters
which originate in process solutions (such as from plating or
galvanizing) and enter wastewaters by dragout to rinses.  These
metals appear in waste streams in widely varying concentrations.

Precious Metals Subcategory - Table 5-17 shows the concentrations
of pollutant parameters found in the precious metals subcategory
raw waste streams.  All of the precious metals shown are used in
Metal Finishing Category operations.  The major constituents are
silver and gold, which are much more commonly used than palladium
and rhodium.  Because of their high cost, precious metals are of
special interest to metal finishers.

Complexed Metals Subcategory - The concentrations of metals found
in complexed metals subcategory raw waste streams are presented in
Table 5-18.  Complexed metals may occur in a number of  unit
operations but come primarily from electroless and immersion
plating.  The most commonly used metals in these operations are
copper, nickel and tin.  Wastewaters containing complexing agents
must be segregated and treated independently of other wastes in
order to prevent further complexing of free metals in the other
streams.

Cyanide Subcategory - The cyanide concentrations found  in cyanide
subcategory raw waste streams are shown in Table 5-19.  The levels
of cyanide range from 0.045 to almost 500 mg/1.  Streams with
high cyanide concentrations normally originate in electroplating
and heat treating processes.  Many other unit operations can also
contribute to the cyanide subcategory.  As mentioned earlier,
cyanide-bearing waste streams should be segregated and  treated
before being combined with other raw waste streams.

Hexavalent Chromium Subcategory - Concentrations of hexavalent
chromium from metal finishing raw wastes are shown in Table 5-20.
Hexavalent chromium enters wastewaters as a result of many unit
operations and can be very concentrated.  Because of its high
toxicity, it requires separate treatment so that it can be
efficiently removed from wastewater.

Oils Subcategory - Pollutant parameters and their concentrations
found in the oily waste subcategory streams are shown in Table
5-21.  The oily waste subcategory for the Metal Finishing Category
is characterized by both concentrated and dilute oily waste
streams that consist of a mixture of free oils, emulsified oils,
greases, and other assorted organics.  The relationship between
the point of origin (unit operations) and the type (concentrated
or dilute) of waste is illustrated in Table 5-22.  Applicable
treatment of oily waste streams can vary dependent upon the
concentration levels of the wastes, but oily wastes will normally
receive specific treatment for oil removal prior to solids
removal waste treatment.
                               V-43

-------
                                                     TABLE 5-16
                                        POLLUTANT CONCENTRATIONS POUND IN THE
                                           COMMON METALS RAW WASTE STREAM
  4.  BENZENE
  6.  CARBON TETRACHLORIDE
 10.  12-DICHLOROETHANE
 11.  111-TRICHLOROETHANE
 14.  112-TRICHLOROETHANE
 22.  PARACHLOROMETACRESOL
 23.  CHLOROFORM
 28.  33-DICHLOROBENZIDINE
 29.  11-DICHLOROETHYLENE
 30.  12T-DICHLOROETHYLENE
 33.  12-DICHLOROPROPYLENE
 38.  ETHYLBENZENE
 39.  FLUORANTHENE
 44.  METHYLENE CHLORIDE
 45.  METHYL CHLORIDE
 46.  METHYL BROMIDE
 48.  DICHLOROBROMOMETHANE
 51.  CHLORODIBROMOMETHANE
 54.  ISOPHORONE
 55. NAPHTHALENE
 57.  2-NITROPHENOL
 63. NNITROSODINPROPLAMIN
 65. PHENOL
 66. B2-ETHYHEXLPHTHALATE
 67. BUTYLBENZYLPHTHALATE
 68. DI-N-BUTYL PHTHALATE
 69. DI-N-OCTYL PHTHALATE
 70. DIETHYL PHTHALATE
 71. DIMETHYL PHTHALATE
78. ANTHRACENE
80. FLUORENE
81. PHENANTHRENE
84. PYRENE
85. TETRACHLOROETHYLENE
86. TOLUENE
87. TRICHLOROETHYLENE
90. DIELDRIN
    ALPHA-ENDOSULFAN
    ENDRIN ALDEHYDE
    ALPHA-BHC
    BETA-BHC
    DELTA-BHC
    ANTIMONY
     ARSENIC
     BERYLLIUM
     CADMIUM
 95
 99
102
103
105
114
115
117
118
119
120
122
123
124
125
127
128
    CHROMIUM    ,TOTAL
    COPPER
    LEAD
    MERCURY
    NICKEL
    SELENIUM
    THALLIUM
    ZINC
  ALUMINUM
  BARIUM
  BORON
  CALCIUM
  COBALT
  FLUORIDES
  IRON
  MAGNESIUM
  MANGANESE
  MOLYBDENUM
  PHOSPHORUS
  SODIUM
  TIN
  TITANIUM
  TOTL SUSPENDD SOLIDS
  VANADIUM
  YTTRIUM
  TOTAL PRIORITY ORGANICS
AV
ERAGE DAIL
Y VALUES (MG/LITER)
MINIMUM MAXIMUM MEAN
<0.001
<0.001
0.003
<0.001
<0.001
0.150
<0.001
<0.001
<0.001
0.001
0.002
<0.001
0.074
<0.001
<0.001
0.002
0.003
0.008
0.013
<0.001
0.024
0.570
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
•C0.001
<0.001
<0.001
<0.001
0.190
<0.001
0.002
<0.001
<0.001
0.009
<0.001
<0.001
0.004
<0.001
0.001
0.002
0.001
<0.001
0.003
0.003
0.003
<0.001
0.004
0.001
0.001
0.009
0.032
0.027
1.67
25.0
0.009
0.021
0.035
5.60
0.059
0.031
0.007
16.7
0.002
0.006
0.556
0.010
0.002
0.001
0.016
0.001
0.003
0.550
0.003
0.150
0.141
•C0.001
0.110
0.005
0.002
1.20
0.074
0.570
0.06
0.002
0.008
0.008
0.310
2.00
0.024
0.570
1.01
1.90
0.010
1.23
0.010
0.235
0.010
0.030
0.160
0.030
0.190
0.066
0.690
0.480
<0.001
0.009
<0.001
<0.001
0.004
<0.001
0.430
0.064
0.044
19.0
35.4
500.
42.3
0.400
415.
0.060
0.062
328.
200.
0.071
4.00
76.2
0.023
36.0
492.
31.1
0.50
0.300
76.7
310.
14.7
0.080
11300.
0.216
0.020
802.
0.008
<0.001
00.003
0.018
<0.001
0.150
0.005
<0.001
0.02
0.003
0.002
0.342
0.074
0.053
0.021
0.002
0.006
0.008
0.173
0.083
0.024
0.570
0.237
0.057
0.001
0.024
<0.001
0.031
0.002
0.002
0.080
0.002
0.190
0.006
0.138
0.022
<0.001
0.009
<0.001
<0.001
0.004
<0.001
0.034
0.016
0.009
1.01
2.20
15.8
1.41
0.018
24.4
0.009
0.010
19.4
61.5
0.043
3.14
51.4
0.01734
5.34
27.8
16.1
0.223
0.200
7.93
151.
3.72
0.039
518.
0.087
0.013
11.3
MEDIAN
0.007
<0.001
0.003
<0.001
<0.001
0.150
<0.001
<0.001
<0.001
0.002
0.002
0.253
0.074
<0.001
0.003
0.002
0.006
0.008
0.185
0.001
0.024
0.570
0.045
0.006
<0.001
0.001
<0.001
0.005
<0.001
0.001
0.080
0.001
0.190
<0.001
0.077
<0.001
<0.001
0.009
<0.001
<0.001
0.004
<0.001
0.006
0.010
0.005
0.008
0.185
0.175
0.12
0.001
0.201
0.005
0.003
0.290
0.290
0.030
3.75
52.2
0.02000
1.12
1.94
13.8
0.085
0.270
3.00
138.
0.856
0.030
62.7
0.036
0.018
0.070
#
PTS
4
37
1
43
21
1
48
1
4
3
1
9
1
27
3
1
2
1
4
61
1
1
15
91
38
79
25
66
7
56
2
55
1
23
17
49
1
1
1
1
1
1
22
31
23
60
89
105
73
32
88
21
21
107
6
3
3
4
3
76
87
4
7
3
83
4
25
3
104
3
3
108
#
ZEROS
2
20
3
14
36
3
17
3
54
2
3
28
3
53
71
3
3
3
4
28
3
3
8
2
27
10
40
17
58
26
2
26
3
36
22
28
3
3
3
3
3
3
84
74
4
48
16
3
35
67
20
5
5
1
2
1
0
0
4
9
1
0
0
1
1
0
60
4
3
1
1
3
                                                                                      FLOW PROPORTIONED
                                                                                    AVERAGE CONCENTRATION
    0.001
   <0.001
    0.003
    0.007
   <0.001
    0.150
   <0.001
   <0.001
    0.069
    0.002
    0.002
    0.225
    0.074
    0.003
    0.013
   0.002
   0.005
   0.008
   0.091
   0.007
   0.024
   0.570
   0.016
   0.008
  •C0.001
   0.006
  <0,001
   0.003
  <0.001
   0.003
  <0.001
   0.004
   0.190
   0.003
   0.007
   0.00058
  <0.001
   0.009
  <0.001
  <0.001
   0.004
  <0.001
   0.002
   0.023
   0.029
   0.104
   1.56
   1.35

   0.207
   0.015
   4.75
   0.017
   0.013
   5.53
 89.0
   0.040
   3.13
 58.5
   0.013
   6.74
 78.4
 17.4
   0.337
  0.198
   7.84
211.
  4.64
   0.058
674.
  0.090
  0.013
  1.64
                                                          44

-------
*»
Ln
           126 SILVER
               GOLD
               PALLADIUM
               RHODIUM
118 CADMIUM
120 COPPER
122 LEAD
124 NICKEL
128 ZINC
    ALUMINUM
    CALCIUM
    IRON
    MAGNESIUM
    MANGANESE
    PHOSPHORUS
    SODIUM
    TIN
                                                             TABLE 5-17
                                                POLLUTANT CONCENTRATIONS FOUND IN THE
                                                  PRECIOUS METALS RAW WASTE STREAM
                                          AVERAGE DAILY VALUES (MG/LITER)
                                      MINIMUM   MAXIMUM   MEAN     MEDIAN
                           0.033
                           0.560
                           0.090
                           0.220
600.
 42.7
  0.120
  0.220
86.2      .385
15.4     0.860
 0.100   0.090
 0.220   0.220
#
TS
12
9
3
1
#
ZEROS
3
6
10
11
FLO
AVERAl
8.53
6.51
0.100
0.220
                                                                                  FLOW PROPORTIONED
                                                             TABLE 5-18
                                                 POLLUTANT CONCENTRATIONS FOUND IN
                                               THE COMPLEXED METALS RAW WASTE STREAM
                                          AVERAGE DAILY VALUES (MG/LITER)
                                      MINIMUM   MAXIMUM   MEAN     MEDIAN
                                                                  PTS   ZEROS
                                                                                  FLOW PROPORTIONED
                                                                                AVERAGE CONCENTRATION
           121 CYANIDE, TOTAL
               CYANIDE, AMN. TO CHLOR 0.005
0.001
0.01
.002
0.026
0.023
.105
17.1
0.038
1.95
.105
0.230
108.
0.013



3.65 0.850 0.067
62.6 11.4 6.72
3.61 1.15 0.420
294. 27.9 3.21
17.6 3.05 0.210
.105 .105 .105
17.1 17.1 17.1
99.0 9.87 0.740
1.95 1.95 1.95
.105 .105 .105
101. 23.0 8.15
108. 108. 108.
6.60 1.57 0.674
TABLE 5-19
POLLUTANT CONCENTRATIONS
THE CYANIDE RAW WASTE
AVERAGE DAILY VALUES (MG/LITER)
MINIMUM
0.045
0.005
MAXIMUM MEAN MEDIAN
500. 111. 44.9
457. 86.5 4.50
9
28
10
25
31
1
1
31
1
1
31
1
10

FOUND IN
STREAM
tt
PTS
20
18
22
3
21
6
0
0
0
0
0
0
0
0
21



#
ZEROS
0
1
1.01
9.69
0.736
20.0
2.52
.105
17.1
5.44
1.95
.105
18.1
108.
1.22



FLOW PROPORTIONED
AVERAGE CONCENTRATION
71.8
61.7
                                                             TABLE 5-20
                                               POLLUTANT CONCENTRATIONS FOUND IN THE
                                                HEXAVALENT CHROMIUM RAW WASTE STREAM
                                          AVERAGE CAILY VALUES (MG/LITER)
                                      MINIMUM   MAXIMUM   MEAN     MEDIAN
                                                                             PTS   ZEROS
                                                                                  FLOW PROPORTIONED
                                                                                AVERAGE CONCENTRATION
               CHROMIUM, HEXAVALENT   0.005
                                     12900.
          420.
         20.
41
             55.6

-------
                                                    TA8LE 5-21
                                       POLLUTANT CONCENTRATIONS FOUND  IN THE
                                                THE OILbf RAW WASTE
                                AVERAGE DAILY VALUES (MG/LITER)
                            MINIMUM    MAXIMUM   MEAN     MEDIAN
                                                                    PTS
                                                                           ZEROS
 1.  ACENAPHTHENE
 4.  BENZENE
 6.  CARBON TETRACHLORIDE
 7.  CHLOROBENZENE
 10 . 12-DICHLOROE'.['HANE
 11.111-TRICHLOROETHAHE
 13 .11-DICHLOROEVHANE
 14.112-TRICHLOROETHANE
 15.1122  TETRACHI.OROETHAN
 17.  BISCHLOROMEVHYLETHER
 18.  BIS2CHLOROEVHYLETHER
 20.2-CHLORONAPHTHALENE
 21.246-TRICHLOROPHENOL
 22.  PARACHLOROMI TACRESOL
 23.  CHLOROFORM
 24.2-CHLOROPHENOL
 29.11-DICHLOROET HYLENE
 30.12T-DICHLOROETHYLENE
 31.24-DICHLOROPFENOL
 34.24-DIMETHYLPhENOL
 37 .12-DIPHENYLH'iDRAZINE
 38.  ETHYLBENZENE
 39.  FLUORANTHENE
 42.  B2CHLOROISOFROPLETHR
 43.  B2CHLOROETHCXYMETHAN
 44.  METHYLENE CHLORIDE
 45.  METHYL CHLORIDE
 47.  BROMOFORM
 48.  DICHLOROBROMOMETHAHE
 49.  TRICLOROFLOROMETHANE
 51.  CHLORODIEROMOMETHANE
 55.  NAPHTHALENE
 56.  NITROBENZENE
 57.  2-NITROPHENOL
 58.  4-NITROPHENOL
 59.  24-DINITROPHENOL
 60.  46-DINITRO-O-CRESOL
 62.  N-NITROSODIPHENLAMIN
 64.  PENTACHLOROPHENOL
 65.  PHENOL
 66.  B 2-ETHYHEXLPHTHALATE
 67.  BUTYLBENZYLPHTHALATE
 68.  DI-N-BUTYL PHTHALATE
 69.  DI-N-OCTYL PHTHALATE
 70.  DIETHYL  PHTHALATE
 71.  DIMETHYL PHTHALATE
 72.  12-BENZANTHRACENE
 73.  BENZO(A)PYRENE
76.  CHRYSENE
77. ACENAPHTHYLENE
78. ANTHRACENE
80.  FLUORENE
81.  PHENANTHRENE
0.057
0.001
0.001
0.011
0.009
0.001
0.002
0.006
0.006
0.009
0.004
0.130
0.010
0.004
0.002
0.076
0.002
0.008
0.010
0.001
0.005
0.001
0.001
0.004
0.003
0.005
0.001
0.010
0.001
260.
0.001
0.001
0.001
0.010
0.010
C.010
0.010
0.004
0.010
0.003
0.002
0.001
0.001
0.004
0.001
0.001
0.002
0.010
0.001
0.077
0.003
0.001
0.002
5.70
0.110
10.0
0.610
2.10
1300.
1.10
1.30
0.570
0.009
0.010
0.130
1.80
800.
0.691
0.620
10.
1.70
0.068
31.0
0.012
5.50
55.0
0.004
0.003
7.60
4.70
0.010
0.010
290.
0.010
260.
0.010
0.320
0.010
10.0
5.70
0.900
50.0
6.61
9.30
10.3
3.10
0.120
1.90
1.20
0.170
0.010
0.073
1.00
2.00
0.760
2.00
2.88
0.012
2.60
0.310
1.12
74.8
.456
0.331
0.288
0.009
0.007
0.130
0.613
104.
0.058
0.348
1.51
0.507
0.039
5.21
0.008
0.380
8.26
0.004
0.003
0.604
1.18
0.010
0.005
275.
0.004
36.3
0.005
0.122
0.010
3.34
2.85
0.488
18.4
1.72
0.818
1.63
0.269
0.062
0.415
0.401
0.047
0.010
0.025
0.406
0.360
0.176
0.393
2.88
0.008
0.097
0.310
1.35
0.265
0.603
0.010
0.288
0.009
0.007
0.130
0.030
2.33
0.010
0.348
0.195
0.088
0.039
0.010
0.008
0.012
0.108
0.004
0.003
0.092
0.009
0.010
0.005
275.
0.002
0.104
0.005
0.035
0.010
0.013
2.85
0.750
5.20
0.440
0.073
0.130
0.016
0.062
0.048
0.001
0.007
0.010
0.002
0.140
0.034
0.075
0.028
2
18
5
2
6
18
11
4
2
1
2
1
3
8
19
2
12
9
2
6
2
16
8
1
1
29
4
1
2
2
3
10
2
3
1
3
2
5
3
3
20
9
15
2
9
3
4
1
3
3
7
7
8
35
19
32
35
31
19
26
33
35
36
35
36
34
29
18
35
25
34
35
31
35
21
29
36
36
8
33
36
35
35
34
27
35
34
36
34
35
32
34
24
17
28
22
35
28
34
23
36
34
34
36
30
29
  FLOW PROPORTIONED
AVERAGE CONCENTRATION

        5.61
        0.013
        0.710
        0.020
        0.907
        5.16
        0.062
        0.123
        0.015
        0.009
        0.007
        0.130
        1.36
       13.4
        0.017
        0.585
        0.316
        0.105
        0.021
       12.8
        0.008
        0.045
        0.614
        0.004
        0.003
        0.827
        4.63
        0.010
        0.010
      275.
        0.004
        1.43
        0.004
        0.010
        0.010
        9.72
        2.85
        0.554
       41.4
        0.277
        0.693
        0.072
        0.498
        0.006
        0.287
        0.676
        0.009
        0.010
        0.003
        0.984
        0.433
        0.140
        0.503

-------
                                              TABLE 5-21 (CONTINUED)
                                       POLLUTANT CONCENTRATIONS FOUND IN
                                            THE OILY RAW WASTE STREAM
                                 AVERAGE DAILY VALUES (MG/LITER)      #
                             MINIMUM    MAXIMUM   MEAN     MEDIAN    PTS
                                              ZEROS
                                     FLOW  PROPORTIONED
                                   AVERAGE CONCENTRATION

 84. PYRENE
 85. TETRACHLOROETHYLENE
 86. TOLUENE
 87. TRICHLOROETHYLENE
 89 ALDRIN
 90. DIELDRIN
 91. CHLORDANE
 92.4 4-DDT
 93.4 4-DDE(P,P-DDX)
 94.4 4-DDD(P,P-TDE)
 95. ALPHA-ENDOSULFAN
 96. BETA-ENDOSULFAN
 97. ENDOSULFAN SULFATE
 98. ENDRIN
 99. ENDRIN ALDEHYDE
100. HEPTACHLOR
101. HEPTACHLOR EPOXIDE
102. ALPHA-BHC
104. GAMMA-BHC  (LINDANE)
105. GAMMA-BHC
107. PCB-1254
110. PCB-1248
    AMMONIA
    B. O. D.
    CHEMICAL OXYGN  DMAND
    OIL & GREAS1
    PHENOLS    ,TOTAL
    TOTL DISSOLVD SOLIDS
    TOT ORGANIC CARBON
    TOTL SUSPEN1 D SOLIDS
0
0
0
0
0
0
0
0
<0
0
0
<0
0
0
0
<0
<0
0
0
0
0
0
0
10
312
65
0
246
3
34
.031
.001
.001
.001
.004
.003
.001
.002
.001
.001
.008
.001
.001
.007
.010
.001
.001
.004
.001
.004
.076
.160
.460
,
m
.0
.002
m
.00
.8
0.
110.
37.
130.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.

-------
                          TABLE 5-22
                  OIL WASTE CHARACTERIZATION


Unit Operation                    Character of Oily Waste Generated
                                      Concentrated     Dilute

   Cleaning                                              X
   Machining                               X             X
   Grinding                                X             X
   Polishing                                             X
   Tumbling (Barrel Finishing)                            X
   Burnishing                              X
   Impact Deformation                      X
   Pressure Deformation                    X
   Shearing                                X
   Heat Treating                           X             X
   Welding                                 X
   Brazing                                 X
   Soldering                               X
   Flame Spraying                          X
   Other Abrasive Jet Machining            X
   Electrical Discharge Machining          X
   Salt Bath Descaling                                   X
   Solvent Degreasing                      X
   Paint Stripping                                       X
   Assembly                                              X
   Taating                                 X             X
                             V-48

-------
The majority of the pollutants listed in Table 5-21 are priority
organics that are used either as solvents or as oil additives  to
extend the useful life of the oils.  Organic priority pollutants,
such as solvents, should be segregated and disposed of or reclaimed
separately-  However, when they are present in wastewater streams
they are most often and at the highest concentration in the oily
waste stream.  This occurs because the organics generally have a
higher solubility in hydrocarbons than in water as is shown in
Table 5-23.  As mentioned previously, oily wastes will normally
receive treatment for oil removal before being directed to waste
treatment for solids removal.

The total priority organics (TPO) concentration figure presented
on Table 5-21 (as well as the TPO figure on Table 5-16 for common
metals) represents the sum of the individual concentrations of
priority pollutants 1-88 and 106-112.  In order to derive TPO
concentrations for common metals and oily wastes, priority
organics numbered 1-88 and 106-112 were summed for each plant.
High organic concentrations were attributed to some source
outside of typical common metal wastes or oily wastes.  These
atypical sources would include batch dumping of solvent cleaners
or the use of solvent contaminated reclaimed oils.

Solvent Subcategory - The solvent subcategory raw wastes are
generated in the Metal Finishing Category by the dumping of
spent solvents from degreasing equipment (including its sumps,
water traps, and stills).  These solvents are predominately com-
prised of compounds that are classified by the EPA as toxic
pollutants.  Table 5-24, extracted from the literature, illustrates
specific solvents employed and shows their annual consumption  for
1974.  Spent solvents should be segregated, hauled for disposal
or reclamation, or reclaimed on site.  Solvents that are mixed
with other wastewaters tend to appear in the common metals or
the oily waste stream.  This is borne out by Tables 5-16 and
5-21.

Table 5-24 shows that in 1974 degreasing solvent consumption
amounted to 1600 million pounds/yr (6.4 million Ib/day) and is expec-
ted to be in the order of 2300 million pounds/yr (9.3 million  Ib/day)
by 1985.  Literature indicates that nearly 100% of all solvents con-
sumed reach the atmosphere, either by direct evaporation from  degreas-
ing equipment or by evaporation subsequent to improper disposal.   In
addition, the same reference estimates that approximately 75%  of
the incidence of solvent degreasing occurs in the metal finishing
industry.  Since degreasing solvents are predominantly concentrated
toxic pollutants that are discharged to the environment from a sin-
gle unit operation, solvent degreasing, the reduction or elimination
of this source will significantly improve the environment.
                                V-49

-------
                           TABLE 5-23
           SOLUBILITY OF TOXIC ORGANIC PARAMETERS
     Parameter

001  Acenaphthene
006  Carbon Tetrachloride
010  1,2-dichloroethane
Oil  1,1,1-trichloroethane
013  1,1-dichloroethane
021  2,4,6-trichlorophenol
022  Parachlorometa Cresol
029  1,1-dichloroethylene
030  1,2-trans-dichloroethylene
034  2,4 Dimethyl Phenol
038  Ethylbenzene
039  Fluoranthene
044  Methylene Chloride
045  Methyl Chloride
049  Trichlorofluoromethane
054  Isophorone
055  Naphthalene
059  2,4-dinitrophenol
060  4,6-dinitro-o-cresol
062  N-nitrosodiphenylamine
064  Pentachlorophenol
065  Phenol
066  Bis(2-ethylhexyl)Phthalate
067  Butyl Benzyl Phthalate
068  Di-n-butyl Phthalate
070  Diethyl Phthalate
077  Acenaphthylene
078  Anthracene
081  Phenanthrene
085  Tetrachloroethylene
086  Toluene
087  Trichloroethylene
  Water
Solubility in
        Hydrocarbons
Insoluble
Very Slightly
Very Slightly
Insoluble
Very Slightly
Slightly
Soluble
Slightly
Slightly
Soluble
Soluble
Insoluble
Slightly
Slightly
Slightly
Slightly
Insoluble
Slightly
Slightly
Insoluble
Slightly
Soluble
Insoluble
Insoluble
Insoluble
Insoluble
Insoluble
Insoluble
Insoluble
Insoluble
Slightly
Insoluble
          Soluble
          Infinitely
          Very to Infinitely
          Soluble
          Soluble
          Soluble
          Very to Infinitely
          Soluble
          Soluble
          Soluble
          Soluble to Infinitely
          Soluble
          Soluble
          Soluble
          Infinitely
          Soluble
          Soluble
          Very Soluble
          Infinitely
          Soluble
          Soluble
          Infinitely
          Soluble
          Soluble
          Soluble
          Soluble
          Very Soluble
          Soluble
          Soluble
          Soluble
          Infinitely
          Infinitely
                               V-50

-------
                         TABLE 5-24
            1974 DECREASING SOLVENT CONSUMPTION

                         Solvent Consumption (Millions of Pounds/Yr).

     Solvent Type               Cold           Vapor           All
                              Cleaning       Degreasing     Degreasing

Halogenated;
  Trichloroethylene              55             282            337
  1,1,1-trichloroethane         180             176            356
  Perchloroethylene              29              90            119
  Methylene Chloride             51              16             67
  Trichlorotrifluoroethane       22              44             66
                                337             608            945

Aliphatics;
  (Kerosenes, Napthas)          489               0            489

Aromatics;
  Benzene                        15               0             15
  Toluene                        31               0             31
  Xylene                         27               0             27
  Cyclohexane                     2               02
  Heavy Aromatics                27             	0             27
                                102               0            102

Oxygenated;
  Ketones
    Acetone                      22               0             22
    Methyl Ethyl Ketone          18               0             18
  Alcohols
    Butyl                        11               0             11
  Ethers                         13             	0             13
                                 64               0             64
Total Solvents:                 992             608           1600
Range of Accuracy:            (+275)           (+55)         (+320)
                             V-51

-------
The primary source of data for this report was 365 Data Collection
Portfolios (DCP's) produced from a random survey of 900 manufacturers
having Standard Industrial Classification (SIC) Codes between 3400
and 3999.  These cover the manufacturing of:  Fabricated Metal Products,
Machinery, Electrical and Electronics Machinery, Transportation Equip-
ment, Measuring Instruments, and Miscellaneous Products.  There are a
total of 159,802 manufacturers in this population  (as listed on the
1977 Dun & Bradstreet tape).  The requested information concerning
manufacturing unit operations and waste treatment methods provided
solvent degreasing unit operation data including waste solvent con-
sumption quantities and frequencies and the disposition of waste sol-
vent.  Additional or missing data were obtained by telephone survey.
Since the manufacturers were selected at random, the survey data were
considered representative of the entire population of manufacturers
within those SIC Codes.

A summary of the DCP data is presented in Table 5-25.  These data
show that 24% of the respondents perform the solvent degreasing op-
eration, that 73% of these have their waste solvents contract hauled,
while 277 discharge directly to the environment.  Based upon a mean
discharge rate of 49.4 Ib/day (as shown in Table 5-25) and a pop-
ulation of 159,802 metal finishing plants, approximately 500,000 Ib/day
of solvent are discharged directly to the environment.

   159,802 (metal finishing plants)
     x 24%  (percent of plants which do solvent degreasing)
    38,352 (number of plants performing solvent degreasing)
     x 27%  (percent of degreasing operations discharging to environment)
    10,355  (number of degreasing operations discharging to environment)
    x 49.4  (mean spent solvent discharge rate (Ib/day)
   511,537 spent solvent discharged to environment (Ib/day)

In addition, approximately 3,300,000 Ib/day are contract hauled.

    38,352 (number of plants doing solvent degreasing)
     x 73%  (percent of plants whose solvent wastes are contract hauled)
    27,997  number of plants whose solvents are contract hauled)
   x 118.7 mean amount of solvents hauled (Ib/day)
 3,323,244 Total spent solvents hauled (Ib/day)

The total solvent comsumption based upon this random survey is
nearly 4 million Ib/day, as compared to estimates in the literature
of 4.8 million Ib/day.

In addition to the DCP information, plant visits provided data that
identified the particular solvents used by relatively large manufac-
turing facilities.  These data show that 43 of the 84 manufacturers
visited (51%)  performed solvent degreasing.   Although the quantity,
                               V-52

-------
                         TABLE 5-25
           SUMMARY OF DCP SOLVENT DECREASING DATA
DCP's Issued

DCP Respondents

DCP Respondents Not Applicable

DCP Respondents Performing Solvent Degreasing

DCP Respondents with Supportive Plant Visit
   Data

DCP Respondents Contacted via Telecon

Degreasers - Waste Solvent Disposal Specified

Degreasers - Waste Solvent Disposal Unspecified


Degreasers That Have Waste Solvent Contract Hauled

     Maximum hauled
     Minimum hauled
     Mean


Degreasers Discharging to Sewer or Surface

     Maximum discharged
     Minimum discharged
     Mean
900

365

277 (76%)

 88 (24%)

 14


 28

 74

 14


 54 (73%)

960 Ibs/day
0.4 Ibs/day
118.7 Ibs/day


 20 (27%)

399 Ibs/day
0.5 Ibs/day
49.4 Ibs/day
                               V-53

-------
frequency, and disposal data are incomplete, 93% of the manufacturers
whose disposition method was reported either used contract hauling or
reclaimed their waste solvents.  Comparing this with the random sur-
vey data (73% reporting contract haulers) indicates that larger man-
ufacturers are more likely to haul or reclaim their spent solvents.

Based upon the DCP responses, a significant quantity of toxic organics
in the form of waste solvents, is being discharged at present.  Cal-
culations using these data show that approximately 500,000 Ib/day
are being discharged at present and this quantity is projected to be
nearly 800,000 Ib/day by 1985.

Table 5-26 presents a listing of all the priority organic pollutants
which are known to be used in various phases of Metal Finishing
Category operations.
                               V-54

-------
          TABLE 5-26

PRIORITY ORGANICS USED IN METAL FINISHING
 4  Benzene
 6  Carbon Tetrachloride
10  1,2-Dichloroethane
11  1,1,1-Trichloroethane
15  1,1,2,2-Tetrachloroethane
21  2,4,6-Trichlorophenol
22  Parachlorometa Cresol
23  Chloroform
29  1,1-Dichloroethylene
30  1,2-Trans-dichloroethylene
34  2,4-Dimethylphenol
38  Ethylbenzene
39  Fluoranthene
44  Methylene Chloride
45  Methyl Chloride
47  Bromoform
49  Trichlorofluoromethane
54  Isophorone
55  Naphthalene
59  2,4-Dinitrophenol
64  Pentachlorophenol
65  Phenol
66  Bis(2-Ethylhexyl)Phthalate
67  Butyl Benzyl Phthalate
68  Di-n-Butyl Phthalate
70  Diethyl Phthalate
71  Dimethyl Phthalate
78  Anthracene
80  Fluorene
81  Phenanthrene
85  Tetrachloroethylene
86  Toluene
87  Trichloroethylene
             V-55

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                         SECTION VI
             SELECTION OF POLLUTANT PARAMETERS
INTRODUCTION

This section presents the pollutant parameters selection for regu-
lation for the Metal Finishing Category.  These parameters were
chosen from the pollutant parameters identified in Section V
based on the following criteria:

          Laboratory analysis results of samples taken during
          screening and verification visits.

          Responses received from the data collection portfolios
          containing pollutant parameter questionnaires.

          Technical information and data received from chemical
          suppliers, equipment manufacturers and previous studies.

Following are an explanation of the rationale for selection and
exclusion of individual pollutant parameters and a presentation of
the parameters selected for each subcategory.

SELECTION RATIONALE

The selection of pollutant parameters for regulation was based
both on sampling analysis data and information received in the
data collection portfolios.

The sampling analysis data is presented for each subcategory in
Section V.  The data collection portfolios contained a questionnaire
on the presence of priority pollutants.  Of the 1,222 returned DCP's
which contained priority pollutant questionaires, 1,048 plants re-
sponded as to which parameters might be present in their wastewater.
Table 6-1 shows the number and type of responses given for each of
the 129 pollutant parameters (plus xylenes and alkyl epoxides).

The parameters available for selection were grouped into four
categories:  toxic organic pollutants, toxic non-organic pollutants,
non-toxic metals and other pollutants.  The selection of parameters
from each of these groups is discussed below.

Toxic Organic Pollutants

The toxic organic pollutants are those parameters numbered 1-113
and 129 on the list of 129 "priority pollutants" presented in
Table 6-1.  The first step in the selection of pollutant parameters
from this grouping was the exclusion of pesticide and herbicide
type parameters.  These parameters, numbered 89-105, 113 and 129,
                              VI-1

-------
                           Table  6-1
             POLLUTANT PARAMETER QUESTIONNAIRE
                       DCP RESPONSES
Pollutant Parameter

001 Acenaphthene

002 Acrolein

003 Acrylonitrile

004 Benzene

005 Benzidine

006 Carbon tetrachloride
    (tetrachloromethane)

007 Chlorobenzene

008 1,2,4-trichlorobenzene

009 Hexachlorobenzene

010 1,2-dichloroethane

Oil 1,1,1-trichloroethane

012 Hexachloroethane

013 1,1-dichloroethane

014 1,1,2-trichloroethane

015 1,1,2,2-tetrachloroethane

016 Chloroethane

017 Bis  (chloromethyl) ether

018 Bis  (2-chloroethyl) ether

019 2-chloroethyl vinyl ether  (mixed)

020 2-chloronaphthalene

021 2,4,6-trichlorophenol

022 Parachlorometa cresol

023 Chloroform  (trichloromethane)
Number of
Responses
1011
1011
1013
1014
1011
1012
1010
1010
1010
1011
1020
1010
1010
1010
1010
1010
1010
1009
1009
1009
1008
1009
1009
KTBP
1
1
3
9
2
4
2
1
1
3
56
3
3
5
2
9
1
1
2
1
2
2
8
BTBP
2
1
12
17
5
10
8
9
4
11
79
7
8
17
12
14
1
1
1
3
4
4
13
BTBA
784
782
111
754
768
756
773
771
778
772
682
774
111
763
765
765
778
111
778
780
111
111
762
KTBJ
224
227
221
234
236
242
227
229
227
225
203
226
222
225
231
222
230
230
228
225
225
226
226
                                  VI-2

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                     Table 6-1
(CONT.)
Pollutant Parameter

024 2-chlorophenol

025 1,2-dichlorobenzene

026 1,3-dichlorobenzene

027 1,4-dichlorobenzene

028 3,3-dichlorobenzidine

029 lfl-dichloroethylene

030 1,2-trans-dichloroethylene

031 2,4-dichlorophenol

032 1,2-dichloropropane

033 1,2-dichloropropylene
    (1,3-dichloropropene)

034 2,4-dimethylphenol

035 2,4-dinitrotoluene

036 2,6-dinitrotoluene

037 1,2-diphenylhydrazine

038 Ethylbenzene

039 Fluoranthene

040 4-chlorophenyl phenyl ether

041 4-bromophenyl phenyl ether

042 Bis(2-chloroisopropyl) ether

043 Bis(2-chloroethoxy) methane

044 Methylene chloride
    (dichloromethane)

045 Methyl chloride  (chloromethane)

046 Methyl bromide (bromomethane)
Number of
Responses
1008
1009
1009
1009
1009
1010
1010
1009
1010
1010
1008
1008
1008
1008
1010
1006
1007
1010
1009
1010
1015
1011
1012
KTBP
2
2
1
2
1
3
2
1
2
1
1
1
1
2
4
1
1
1
1
2
38
10
3
BTBP
3
2
2
3
1
2
2
4
1
1
3
1
1
1
7
2
2
2
2
4
49
11
1
BTBA
782
111
780
778
111
784
780
779
776
780
779
781
781
780
778
779
776
779
778
776
718
762
781
KTB
221
228
226
226
230
221
226
225
231
228
225
225
225
225
221
224
228
228
228
228
210
228
227
                                 VI-3

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                      Table 6-1   (CONT.)
Pollutant Parameter



 047 Bromoform  (tribromomethane)



 048 Dichlorobromomethane



 049 Trichlorofluoromethane



 050 Dichlorodifluoromethane



 051 Chlorodibroraomethane



 052 Hexachlorobutadiene



 053 Hexachlorocyclopentadiene



 054 Isophorone



 055 Naphthalene



 056 Nitrobenzene



 057 2-nitrophenol



 058 4-nitrophenol



 059 2,4-dinitrophenol



 060 4,6-dinitro-o-cresol



 061 N-nitrosodimethylamine



 062 N-nitrosodiphenylamine



 063 N-nitrosodi-n-propylamine



 064 Pentachlorophenol



 065 Phenol



 066 Bis(2-ethylhexyl) phthalate



 067 Butyl benzyl phthalate



 068 Di-n-butyl phthalate



 069 Di-n-octyl phthalate



 070 Diethyl phthalate
Number of
Responses
1014
1014
1015
1014
1014
1014
1012
1012
1015
1015
1013
1013
1013
1012
1014
1013
1014
1012
1020
1014
1014
1013
1013
1012
KTBP
1
2
5
6
2
1
1
2
3
1
1
1
1
1
2
1
2
2
78
6
5
6
7
6
BTBP
2
2
11
14
1
2
1
10
14
9
2
2
2
1
1
1
2
8
40
4
4
4
4
2
BTBA
781
778
774
767
779
783
782
111
769
776
780
780
779
781
784
784
780
775
693
779
779
111
775
778
KTBA
230
232
225
227
232
228
228
223
229
229
230
230
231
229
227
227
230
227
209
225
226
226
227
226
                                 VI-4

-------
                      Table  6-1   (CONT.)
Pollutant Parameter

 071 Dimethyl phthalate

 072 1,2-benzanthracene
    (benzo(a)anthracene)

 073 Benzo(a)pyrene  (3,4-benzopyrene)

 074 3,4-Benzofluoranthene
    (benzo(b)fluoranthene)

 075 11,12-benzofluoranthene
    (benzo(k)fluoranthene)

 076 Chrysene

 077 Acenaphthylene

 078 Anthracene

 079 1,12-benzoperylene
    (benzo(ghi)perylene)

 080 Fluorene

 081 Phenanthrene

 082 1,2,5,6-dibenzanthracene
    (dibenzo(a,h)anthracene)

 083 Indeno(l,2,3-cd)  pyrene
    (2,3-o-phenylene  pyrene)

 084 Pyrene

 085 Tetrachloroethylene

 086 Toluene

 087 Trichloroethylene

 088 Vinyl  chloride  (chloroethylene)

 089 Aldrin
Number of
Responses
1014
1014
1014
1014
1014
1014
1014
1012
1012
1011
1010
1009
1009
1009
1008
1016
1011
1009
1010
KTBP
6
4
3
3
3
3
3
3
3
7
1
3
1
4
11
39
31
6
2
BTBP
2
2
2
1
1
1
1
3
1
1
1
1
1
3
19
69
72
9
3
BTBA
779
779
111
779
779
780
779
776
779
778
781
111
111
775
758
713
699
111
773
KTBJ
227
229
232
231
231
230
231
230
229
225
227
228
230
227
220
195
209
217
232
                                VI-5

-------
                      Table 6-1   (CONT.)
Pollutant Parameter

 090 Dieldrin

 091 Chlordane (technical mixture
     and metabolites)

 092 4,4-DDT

 093 4,4-DDE (p,p-DDX)

 094 4,4-DDD (p,p-TDE)

 095 Alpha-endosulfan

 096 Beta-endosulfan

 097 Endosulfan sulfate

 098 Endrin

 099 Endrin aldehyde

 100 Heptachlor

 101 Heptachlor epoxide
     (BHC-hexachlorocyclohexane)

 102 Alpha-BHC

 103 Beta-BHC

 104 Gamma-BHC

 105 Delta-BHC
     (PCB-polychlorinated biphenyls)

 106 PCB-1242 (Arochlor 1242)

 107 PCB-1254 (Arochlor 1254)

 108 PCB-1221 {Arochlor 1221)

 109 PCB-1232 (Arochlor 1232)

 110 PCB-1248 (Arochlor 1248)

 111 PCB-1260 (Arochlor 1260)
Number of
Responses   KTBP  BTBP  BTBA  KTBA
1008
1008
1008
1008
1008
1008
1008
1008
1008
1008
1008
1008
1008
1008
1008
1009
1010
1009
1009
1009
1008
1006
1
1
1
1
1
1
1
2
1
2
1
1
1
1
1
5
7
4
2
4
3
4
2
2
2
3
3
2
2
2
2
2
3
2
2
2
2
4
10
6
4
4
5
6
775
I'll
769
773
777
778
778
779
773
111
775
776
773
773
770
767
751
755
764
764
760
752
230
228
236
231
227
227
227
225
232
227
229
229
232
232
235
233
242
244
239
237
240
244
                                VI-6

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                      Table 6-1  (CONT.)
Pollutant Parameter

 112 PCB-1016 (Arochlor 1016)

 113 Toxaphene

 114 Antimony

 115 Arsenic

 116 Asbestos

 117 Beryllium

 118 Cadmium

 119 Chromium

 120 Copper

 121 Cyanide

 122 Lead

 123 Mercury

 124 Nickel

 125 Selenium

 126 Silver

 127 Thallium

 128 Zinc

 129 2,3,7,8-tetrachlorodibenzo-
     p-dioxin (TCDD)
Number of
Responses
990
990
990
996
987
986
1012
1048
1038
1032
1017
1002
1039
990
1007
990
1032
KTBP
2
1
36
42
15
36
286
653
599
477
292
93
546
40
192
26
524
BTBP
5
3
38
18
23
38
57
98
106
87
88
26
112
29
56
14
75
BTBA
747
757
712
702
730
702
486
220
250
333
484
644
282
704
574
721
321
KTBA
236
229
204
234
219
210
183
77
83
135
153
239
99
217
185
229
112
990
14
743   227
 KTBP  -  Known  to  be  Present
 BTBP  -  Believed  to  be  Present
 KTBA  -  Known  to  be  Absent
 BTBA  -  Believed  to  be  Absent
                                 Vl-7

-------
either were not detected through sampling or were found  upon
rare occasion in low concentrations.  These pesticide type para-
meters and their mean concentrations are displayed in Table 6-2.
There is no reason why pesticide type parameters should  be pre-
sent within the wastewater streams generated by the Metal
Finishing Category.

The remaining toxic organics (1-88, 106-112) are those which
might be expected to be present in metal finishing waste streams
due to cleaning wastes and oily wastes.  During the analysis of
the wastewater samples, it was found that a variety of toxic
organics could be present in both common metals and oily waste
streams.  The toxic organics found above a concentration of 0.1
mg/1 in the common metals and oily wastes raw waste streams are
listed in Tables 6-3 and 6-4, respectively.  It was also found
that the types of organic toxics detected varied from plant to
plant.  Because this large variety of toxic organics is present
in the Metal Finishing Category and because of the difficulty
involved with regulating such a large number of pollutants, a
total toxic organics (TTO) heading has been established which
covers pollutant parameters 1-88 and 106-112.  The TTO parameter
is regulated in both the common metal and oily waste subcate-
gories, as shown later in this section.

Toxic Non-organic Pollutants

The toxic non-organic pollutants are the "priority pollutants"
which are numbered 114-128 on Table 6-1 and consist of toxic
metals and cyanide.  Cyanide, which is commonly used within the
Metal Finishing Category (as evidenced by the 111 mg/1 mean
concentration of total cyanide in the cyanide raw waste  stream),
was an obvious selection as a pollutant parameter.

Of the toxic metals, cadmium, chromium, copper, lead, nickel, silver
and zinc were found at significant concentration levels  in the
raw waste.  Table 6-5 shows the concentration of toxic metals
that were found in the common metals raw waste stream.   Con-
sequently, cyanide, cadmium, chromium, copper, lead, nickel,
silver and zinc have been selected as pollutant parameters to
be regulated.

Non-toxic Metals

The non-toxic metals group contains those metals which were
analyzed but were not listed among the 129 priority pollutants.
Table 6-6 presents the non-toxic metals, their mean concentra-
tions (when found) and the number of points at which they were
found in the common metals raw waste stream.  Since these metals
are classified as non-toxic, a parameter would have to be found
at high concentrations with high frequency to be selected for
regulation.  Iron is the only non-toxic metal to meet these
criteria and is selected as a pollutant parameter to be  regulated.
                               VI-8

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Number
                         Table 6-2
             PESTICIDE TYPE PRIORITY POLLUTANTS
                NOT SELECTED FOR REGULATION
Parameter
    Mean
Concentration
089
090
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
113
129
Aldrin
Dieldrin
Chlordane
(Technical Mixtures and Metabolites)
4,4-DDT
4,4-DDE (P,P-DDX)
4,4-DDD (P,P-TDE)
Alpha-endosulf an
Beta-endosulfan
Endosulfan Sulfate
Endrin
Endrin aldehyde
Heptachlor
Heptachlor Epoxide
Alpha-BHC
Beta-BHC
Gamma-BHC
Delta-BHC
Toxaphene
2,3,7, 8-Te trachlorodibenzo-p-dioxin
<0.0073
<0.0026
<0.0069
<0.01
<0.014
<0.005
<0.018
<0.003
<0.0097
<0.008
<0.012
<0. 00001
<0. 00001
<0.012
<0.004
<0.0077
<0.0073
Not Detected

          (TCDD)
                                         Not  Detected
                               VI-9

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                         Table 6-3
         COMMON METALS SUBCATEGORY - TOXIC ORGANICS
          WHICH OCCUR AT A CONCENTRATION >0.1 mg/1


Number         Parameter                               # Points

 Oil           1,1,1-Trichloroethane                       2

 022           Parachlorometa Cresol                       1

 023           Chloroform                                  1

 029           1,1-Dichloroethylene                        1

 038           Ethylbenzene                                6

 044           Methylene Chloride                          6

 054           Isophorone                                  2

 055           Naphthalene                                 4

 063           N-Nitrosodi-n-Propylamine                   1

 065           Phenol                                      5

 066           Bis (2-Ethylhexyl) Phthalate               11

 068           Di-n-Butyl Phthalate                        3

 070           Diethyl Phthalate                           7

 080           Fluorene                                    1

 084           Pyrene                                      1

 086           Toluene                                     6

 087           Trichloroethylene                           1
                              VI-10

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                         Table 6-4
          OILY WASTE SUBCATEGORY - TOXIC ORGANICS
          WHICH OCCUR AT A CONCENTRATION >0.1 mg/1
Number         Parameter                               # Points

 001           Acenaphthene                                1

 004           Benzene                                     1

 006           Carbon Tetrachloride                        2

 007           Chlorobenzene                               1

 010           1,2-Dichloroethane                          5

 Oil           1,1,1-Trichloroethane                      10

 013           1,1-Dichloroethane                          6

 014           1,1,2-Trichloroethane                       1

 015           1,1,2,2-Trichloroethane                     1

 020           2-Chloronaphthalene                         1

 021           2,4,6-Trichlorophenol                       1

 022           Parachlorometa Cresol                       5

 023           Chloroform                                  1

 024           2-Chlorophenol                              1

 029           1,1-Dichloroethylene                        6

 030           1,2-Trans-Dichloroethylene                  4

 034           2,4-Dimethylephenol                         2

 038           Ethylbenzene                                2

 039           Fluoranthene                                4

 044           Methylene Chloride                         15

 045           Methyl Chloride                             1

 049           Trichlorofluoromethane                      2

 055           Naphthalene                                 5
                               VI-11

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                   Table 6-4 (Continued)

Number         Parameter                               # Points

 057           2-Nitrophenol                               1

 059           2,4-Dinitrophenol                           1

 060           4,6-Dinitro-o-Cresol                        1

 062           N-Nitrosodiphenylamine                      3

 064           Pentachlorophenol                           2

 065           Phenol                                      8

 066           Bis (2-Ethylhexyl) Phthalate                8

 067           Butyl Benzyl Phthalate                      5

 068           Di-n-Butyl Phthalate                        4

 069           Di-n-Octyl Phthalate                        1

 070           Diethyl Phthalate                           2

 071           Dimethyl Phthalate                          1

 072           1,2-Benzanthracene
               (Benzo (a) Anthrocene)                      1

 077           Acenaphthylene                              2

 078           Anthracene                                  2

 080           Fluorene                                    3

 081           Phenanthrene                                2

 084           Pyrene                                      1

 085           Tetrachloroethylene                         5

 086           Toluene                                     7

 087           Trichloroethylene                           6

 107           PCB-1254 (Arochlor 1254)                    1

 110           PCB-1248 (Arochlor 1248)                    2
                                VI-12

-------
                         Table 6-5
          RAW WASTE CONCENTRATIONS OF TOXIC METALS

                                                      Mean
Number    Parameter                               Concentration

 114      Antimony                                    0.034

 115      Arsenic                                     0.016

 116      Asbestos                                Not Analyzed

 117      Beryllium                                   0.009

 118      Cadmium                                     0.934

 119      Chromium                                  420.0*

 120      Copper                                     14.5

 122      Lead                                        1.63

 123      Mercury                                     0.014

 124      Nickel                                     23.6

 125      Selenium                                    0.009

 126      Silver                                     86.2**

 127      Thallium                                    0.010

 128      Zinc                                      309.0
* Mean hexavalent chromium value in hexavalent chromium raw
  waste stream.

** Mean silver concentration as measured in precious metal
   raw waste stream.
                               VI-13

-------
                         Table 6-6
        RAW WASTE CONCENTRATIONS OF NON-TOXIC METALS
Parameter

Aluminum

Barium

Boron

Cobalt

Gold

Iron

Magnesium

Manganese

Molydenum

Palladium

Rhodium

Tin

Titanium

Vanadium

Yttrium
Mean Concentration

     31.3

      0.043

      3.14

      0.017

     15.4*

    505.0

     16.1

      0.223

      0.122

      0.100*

      0.220*

      2.68

      0.888

      0.087

      0.014
# Of Points
Where Found

     14

      3

      3

      3

      9

    101

      4

      7

      5

      3

      1

     38

      5

      3

      3
* Mean concentration as measured in the precious metals  raw
  waste stream.
                               VI-14

-------
Other Pollutants

There are other pollutant parameters which are normally controlled
to maintain water quality.  Total suspended solids  (TSS) is a
traditional pollutant parameter which is not necessarily harmful
in itself, but can serve to control the discharge of harmful
pollutants.  Oil and grease is a traditional pollutant parameter
which can cause odor and taste problems with water  and kill
aquatic organisms.  As evidenced by its mean concentration in the
oily wastes raw waste stream (40,700 mg/1), oil is  a significant
pollutant in the Metal Finishing Category.

POLLUTANT PARAMETERS SELECTED

Tables 6-7 through 6-12 present the pollutant parameters selected
for regulation for each subcategory.  These tables  also show the
mean raw waste concentration of each pollutant and  the number of
data points available for each parameter.

For the solvent subcategory, all spent solvents that contain
priority pollutants require disposal regulation.  These spent
solvents are a source of concentrated priority pollutants and
should not be allowed to enter the waste treatment  system.
Appropriate disposal is discussed in Section VII.
                               VI-15

-------
                         Table 6-7
  COMMON METALS SUBCATEGORY - SELECTED POLLUTANT PARAMETERS
     Pollutant
     Parameter

118  Cadmium

119  Chromium

120  Copper

     Iron

122  Lead

124  Nickel

128  Zinc

     Total Suspended Solids

     Total Toxic Organics*
    Mean
Concentration
    mg/1

    0.934

    2.48

   14.5

  505.0

    1.63

   23.6

  309.0

  487.0

   11.3
 Number Of
Data Points

    (71)

    (50)

   (116)

   (101)

    (87)

    (91)

   (121)

   (117)

   (107)
* Pollutant Parameters 1-88 and 106-112 on Table 6-1.
                         Table 6-8
  PRECIOUS METALS SUBCATEGORY - SELECTED POLLUTANT PARAMETERS
     Pollutant
     Parameter

124  Silver
    Mean
Concentration
    mg/1	

    86.2
 Number Of
Data Points

    (12)
                             VI-16

-------
                         Table 6-9
COMPLEXED METALS SUBCATEGORY - SELECTED POLLUTANT PARAMETERS
     Pollutant
     Parameter

120  Copper

122  Lead

124  Nickel

128  Zinc

     Iron

     Total Suspended Solids
    Mean
Concentration
    11.4

     1.15

    17.9

     3.05

     9.88

    19.5
 Number Of
Data Points

    (28)

    (10)

    (25)

    (31)

    (31)

    (26)
                         Table 6-10
HEXAVALENT CHROMIUM SUBCATEGORY - SELECTED POLLUTANT PARAMETERS
     Pollutant
     Parameter

     Chromium, Hexavalent
    Mean
Concentration
    mg/1

   420.0
 Number Of
Data Points

   (41)
                         Table 6-11
     CYANIDE SUBCATEGORY - SELECTED POLLUTANT PARAMETERS
     Pollutant
     Parameter

121  Cyanide

     Cyanide, Amn. To Chlor.
    Mean
Concentration
    mg/1

    111.0

     86.5
 Number Of
Data Points

    (20)

    (18)
                               VI-17

-------
                         Table 6-12
      OILS SUBCATEGORY - SELECTED POLLUTANT PARAMETERS

                                  Mean
     Pollutant                Concentration             Number  Of
     Parameter                    mg/1	            Data  Points

     Oil and Grease             40,700                     (37)

     Total Toxic Organics*         112.0                   (37)


* Pollutant Parameters 1-88 and 106-112 on Table 6-1.
                               VI-18

-------
                         SECTION VII
               CONTROL AND TREATMENT TECHNOLOGY
 INTRODUCTION

 This section describes the treatment techniques currently used
 or available to remove or recover wastewater pollutants normally
 generated by the Metal Finishing Category.  Included is a discus-
 sion of individual wastewater treatment technologies and in-plant
 control and treatment technologies.  Pertinent treatment and con-
 trol technology is discussed specifically for each of the seven
 raw waste subcategories that are present.  The technologies pre-
 sented are applicable to the metal finishing industry for both
 direct and indirect dischargers and reflect the entire metal
 finishing data base.

 The raw wastes for the Metal Finishing Category were initially sub-
 divided into two constituent types, inorganic and organic wastes.
 These were then further subdivided into the specific types of waste
 that occur in each of these two major areas and grouped into the
 following seven subcategories:
MAJOR SUBDIVISION

INORGANIC
WASTES

ORGANIC
WASTES
SUBCATEGORY
1.
2.
3.
4.
5.
6.
7.
Common Metals
Precious Metals
Complexed Metals
Hexavalent Chromium
Cyanide
Oils
Solvents
 Treatment  for  the wastes from each of these seven subcategories is
 shown  schematically in Figure 7-1.  This schematic illustrates the
 types  of treatment that are needed for wastes that exist in each
 subcategory.   The specific treatment required for these wastes is
 as  follows:
                             PRIMARY
                            TREATMENT
SUBCATEGORY
     FINAL
   TREATMENT
 Common  Metals
 Precious  Metals

 Complexed  Metals
 Hexavalent  Chromium
 Cyanide
 Oils
.Solvents
                Precious Metals Recovery
                Chromium Reduction
                Cyanide Destruction
                Oily Waste Removal
Metals Removal
Optional (depending on
other wastes present)
Complexed Metals Removal
Metals Removal
Metals Removal
Metals Removal
Haul or Reclaim
                             VII-1

-------
Manufacturing Facility
Raw Waste Sources

Raw Waste Discharge si. £kR f
(Treatment System * ' * *
Influent) . ,
1 1 . 1
Waste Treatment ! Oily Waste , | Chromium j
!
(If Applicable) ! Removal ! 1 Reduction j
1 	 	 J L 	 	 ;
Treated
Effluent ''v
i i


(
i

t,c Q
7^- ^
Common
Metals
1 	
! Cyar

SD (.
s *-* \
•* -1
Solvents
.- T
I

i
)E OF

ide : 1 j Complexed j j Precious .
! Metals i Metals
! Destruction | 1 Removal | Recovery 1
1 	 	 i ! 1 	 i 1 	 i
*
t
Without
^^

jc ItD
^ ||S ^
1
Cyanide j
*

JG Raw Waste
(Common Metals)
• Comnton !


-------
The wastewater stream segregation shown in Figure  7-1  is  current
common practice in the Metal Finishing Category, as discussed
in Section IV.  This stream segregation allows the recovery  of
precious metals, the reduction of hexavalent chromium  to  triva-
lent chromium, the destruction of cyanide, and the removal/
recovery of oils prior to the removal of the common metals that
are also present in these streams.  Segregation of these  streams
reduces the flow rate of wastewater to be treated  in each compon-
ent and accordingly reduces the cost of this primary treatment.
The complexed metals wastewaters require segregated treatment to
preclude the complexing of other metal wastes in the treatment sys-
tem.

This section is divided into subsections with the  following
headings: Applicability of Treatment Technologies, Treatment of
Common Metals Wastes, Treatment of Precious Metals Wastes,
Treatment of Complexed Metals Wastes, Treatment of Hexavalent
Chromium Wastes, Treatment of Cyanide Wastes, Treatment of Oily
Wastes, Treatment of Solvent Wastes, Treatment of  Sludges, and
In-Process Control Technology.  The Applicability of Treatment Tech-
nologies Subsection defines specific applications of individual
treatment technologies and references the location of  their  respective
descriptions within this section.

The subsections that discuss treatment present three specific
levels of treatment options for the common metals and  oily waste
subcategories.  The organization of each of these  subsections
is such that the Option 1 system is described, the particular
treatment components that are applicable to the first  level  option
(Option 1) for that subcategory are described, and their perfor-
mance is presented.  Then, the Option 1 performance level is
presented.  The information relative to Options 2 and  3 is de-
veloped and discussed in a similar ma/iner for both subcategories.
The subsections that discuss treatment for other subcategories
present only a single option because only one level of treatment
is applicable.

The In-Process Control Technology Subsection discusses techniques
for process water usage reduction, alternative processes, inte-
grated waste treatment, and good housekeeping.
                              VI1-3

-------
APPLICABILITY OF TREATMENT TECHNOLOGIES

This subsection identifies the component technologies that are
applicable for the treatment of raw wastes that are generated
by industries that perform the metal finishing operations des-
cribed in Section III.  Table 7-1 lists the component technologies,
shows their specific application to the Metal Finishing Category,
and indicates the page on which each is described.  Table 7-2
illustrates the applicability of each technology to each of the
waste characteristic subcategories.

Each treatment component is functionally described and discussions
are presented of the following:  application and performance;
advantages and limitations; operational factors of reliability,
maintainability, and solid waste aspects; and the demonstration
status.  In some instances the technique described has been demon-
strated in another industry to successfully remove a particular
waste.  Wherever the waste characteristics are similar to that
for a Metal Finishing Category wastewater subcategory, performance
data have been shown to better illustrate the capabilities of the
treatment techniques being described.
                             VI1-4

-------
                          TABLE  7-1
              INDEX AND  SPECIFIC APPLICATION OF
                    TREATMENT  TECHNOLOGIES
Technology

Aerobic Decom-
  position

Carbon Adsorption

Centrifugation

Chemical Reduction

Coalescing

Diatomaceous Earth
  Filtration

Electrochemical
  Oxidation

Electrochemical
  Reduction

Electrochemical
  Regeneration

Electrodialys is

Electrolytic
  Recovery

Emulsion Breaking

Evaporation


Flotation

Granular Bed Fil-
  tration

Gravity Sludge
  Thickening

High pH Precipi-
  tation
Application or Potential Application
	to Metal Finishing	      Page

Oil breakdown and organics removal
Removal of trace metals and organics

Sludge dewatering, oil removal

Treatment of chromic acid and chromates

Oil removal

Metal hydroxides and suspended solids
  removal

Destruction of free cyanide and cyanates


Reduction of chromium from metal finishing
  and cooling tower blowdowns

Conversion of trivalent chromium to hexa-
  valent valence

Recovery of process baths

Recovery of precious and common metals


Breakdown of emulsified oil mixtures

Concentration and recovery of process
  chemicals

Suspended solids and oil removal

Solids polishing of settling tank
  effluent

Dewatering of clarifier underflow


Removal of complexed metals
                            VI1-5

-------
Technology
                       TABLE  7-1  (Con't)
             INDEX AND SPECIFIC APPLICATION OF
                   TREATMENT  TECHNOLOGIES
                    Application or  Potential  Application
                    	to Metal Finishing	
Paqe
Hydroxide Precipi-
  tation

Insoluble Starch
  Xanthate

Ion Exchange

Membrane Filtra-
  tion

Oxidation by
  Chlorine

Oxidation by Hy-
  drogen Peroxide
                    Dissolved metals  removal
                    Dissolved metals removal
                    Recovery or removal of  dissolved  metals

                    Dissolved metals and  suspended  solids
                      removal

                    Destruction of cyanides  and  cyanates
                    Cyanide destruction  and metals  removal
Oxidation by Ozone  Destruction of  cyanides  and  cyanates

                    Destruction of  cyanides  and  cyanates
Oxidation by Ozone
  w/UV Radiation

Peat Adsorption

Pressure Filtra-
  tion

Resin Adsorption

Reverse Osmosis


Sedimentation

Skimming

Sludge Bed Drying

Sulfide Precipita-
  tion

Ultrafiltration
                    Dissolved metals removal

                    Sludge dewatering or  suspended  solids
                      removal

                    Removal of organics

                    Removal of dissolved  salts  for  water
                      reuse

                    Suspended solids and  metals removal

                    Free oil removal

                    Sludge dewatering

                    Dissolved metals removal
                    Oil and suspended  solids  removal  and
                      paint purification
Vacuum Filtration   Sludge dewatering
                             VI1-6

-------
                                                          TABLE 7-2
                                        APPLICABILITY OF  TREATMENT TECHNOLOGIES  TO
                                                 RAW WASTE  SUBCATEGORIES
        Technology

Aerobic Decomposition
Carbon Adsorption
Centrifugation
Chemical Reduction
Coalescing
Diatomaceous Earth
  Filtration
Electrochemical Oxidation
Electrochemical Reduction
Electrochemical Regeneration
Electrod ialys is
Electrolytic Recovery
Emulsion Breaking
Evaporation
Flotation
Granular Bed Filtration
Gravity Sludge Thickening
High pH Precipitation
Hydroxide Precipitation
Insoluble Starch Xanthate
Ion Exchange
Membrane Filtration
Oxidation by Chlorine
Oxidation by Hydrogen Peroxide
Oxidation by Ozone
Oxidation by Ozone with
  UV Radiation
Peat Adsorption
Pressure Filtration
Resin Adsorption
Reverse Osmosis
Sedimentation
Skimming
Sludge Bed Drying
Sulfide Precipitation
Ultrafiltration
Vacuum Filtration
Common
Metals
  x
  x

  X
  X
  X
  X
Precious
Metals
  x
  X


  X
  X
  X
  X
Complexed
Metals
X
X
X
X

X
X
X
X
X
X

X

X
X
X
X

X
X
X
X
X
X
X
X
  X
  X


  X
  X
  X
  X
Chromium   Cyanide
Bearing    Bearing
Oily
Wastes
                                  x
                                  X
                                  X
                                             X
                                             X
                                             X
                                             X
                                                       X
                                                       X
                                                       X


                                                       X
                                                       X
Solvent
Wastes   Sludge

   x
   X
In-Process
                                                                          x
                                                                          X
                                                                          X
                                                       X


                                                       X
                       X
                       X
            X

            X

-------
TREATMENT OF COMMON METALS WASTES

Introduction

Common metals wastes can be generated in the Metal Finishing
Category by the unit operations that have previously been
described.  The treatment methods used to treat these wastes
are discussed in this section and fall into two groupings -
recovery techniques and solids removal techniques.  Recovery
techniques are treatment methods used for the purpose of recover-
ing or regenerating process constituents which would otherwise
be lost in the wastewater or discarded.  Included in this group
are evaporation, ion exchange, electrolytic recovery, electro-
dialysis and reverse osmosis.  Solids removal techniques are
employed to remove metals and other pollutants from process
wastewaters to make these waters suitable for reuse or discharge.
These methods include hydroxide and sulfide precipitation,
sedimentation, diatomaceous earth filtration, membrane filtra-
tion, granular bed filtration, sedimentation, peat adsorption,
insoluble starch xanthate treatment and flotation.

This subsection presents the treatment systems that are applic-
able to common metals removal for treatment Options 1, 2, and 3;
describes the treatment techniques applicable to each option;
and defines the effluent performance levels for each of those
options.  Option 1 common metals removal incorporates hydroxide
precipitation and sedimentation.  Option 2 for common metals
removal consists of the addition of filtration devices to the
Option 1 system.  The Option 3 treatment system for common metals
wastes consists of the Option 2 end-of-pipe treatment system
with the addition of in-plant controls for lead and cadmium.
Alternative treatment techniques that can be applied to provide
Option 1, 2, or 3 system performance are described following the
Option 3 discussion.

TREATMENT OF COMMON METAL WASTES - OPTION 1

The Option 1 system for the treatment of common metals wastes
consists of hydroxide precipitation followed by sedimentation,
as is shown in Figure 7-2.  This system accomplishes the end-
of-pipe metals removal from all common metals bearing waste-
water streams that are present at a facility.  The recovery of
precious metals, the reduction of hexavalent chromium, the removal
of oily wastes, and the destruction of cyanide must be accomplished
prior to common metals removal, as is shown in Figure 7-1.  Hexa-
valent chromium bearing wastes must undergo chemical reduction  in
order to reduce hexavalent chromium to trivalent chromium.
                              VI1-8

-------
    Chemical
    Addition
                      Common Metals
                        Wastewater
                            I
  Hydroxide

Precipitation
                      Sedimentation
                           T
                      Effluent Water
                      Sludge
                    FIGURE 7-2
TREATMENT OF  COMMON  METALS  WASTES  - OPTION 1
                          VI1-9

-------
Cyanide bearing wastes must undergo oxidation to destroy  the  cy-
anide in the wastewater.  Cyanide, as well as being a  highly
toxic pollutant, will complex metals such as copper, cadmium,
and zinc and prevent efficient removal of these metals in the
solids removal device.  Similarly, complexed metal wastes must
be kept segregated and treated separately to avoid complexing
metals in the primary solids removal device.  Complexed metal
wastes should be treated in a separate solids removal  device
such as a membrane filter or a high pH clarifier.  The specific
techniques for the treatment of wastes from all other  subcate-
gories, a description of the three levels of treatment options
for each subcategory, and the performance for all levels  of these
options are presented in subsequent subsections.

The treatment techniques incorporated in the Option 1  common
metals waste treatment system include pH adjustment, hydroxide
precipitation, flocculation, and sedimentation.  Sedimentation
may be carried out with equipment such as clarifiers,  tube set-
tlers, settling tanks, sedimentation lagoons and various  filtra-
tion devices using hydroxide precipitation.  The following para-
graphs describe the hydroxide precipitation and sedimentation
techniques that are employed for the Option 1 common metals
treatment system.

HYDROXIDE PRECIPITATION

Dissolved heavy metal ions are often chemically precipitated as
hydroxides so that they may be removed by physical means  such
as sedimentation, filtration, or centrifugation.  Reagents com-
monly used to effect this precipitation include alkaline  compounds
such as lime and sodium hydroxide.  Calcium hydroxide  precipitates
trivalent chromium and other metals as metal hydroxides and pre-
cipitates phosphates as insoluble calcium phosphate.   These treat-
ment chemicals may be added to a flash mixer or rapid  mix tank, or
directly to the sedimentation device.  Because metal hydroxides
tend to be colloidal in nature, coagulating agents may also be
added to facilitate settling.  Figure 7-3 illustrates  typical che-
mical precipitation equipment as well as the associated sedimen-
tation device.

After the solids have been removed, final pH adjustment may be
required to reduce the high pH created by the alkaline  treatment
chemicals.
                             VII-10

-------
               Rapid Sedimentation
                       and
           Continuous Gravity Drainage
                          Tube  Settling    Flocculator
                                             Drive
               Effluent
                    Chemicals
   Inlet
Wastewater
Collection
  Trough
    L
                                    Flocculator Tube
                                        Settler
          Rapid
         Mix Tank
                                                             Sludge Siphon
                                                Sludge Collector
                                 FIGURE  7-3
                     PRECIPITATION AND SEDIMENTATION
                                      VII-11

-------
Application and Performance

Hydroxide precipitation is used in metal finishing for precipita-
tion of dissolved metals and phosphates.  It can be utilized in
conjunction with a solids removal device such as a clarifier or
filter for removal of metal ions such as iron, lead, tin, copper,
zinc, cadmium, aluminum, mercury, manganese, cobalt, antimony,
arsenic, beryllium, molybdenum, and trivalent chromium.  The pro-
cess is also applicable to any substance that can be transformed
into an insoluble form like soaps, phosphates, fluorides, and
a variety of others.

The performance of hydroxide precipitation depends on several
variables.  The most important factors affecting precipitation
effectiveness are:

     1.   Addition of sufficient excess anions to drive the
          precipitation reaction to completion.

     2.   Maintenance of an alkaline pH throughout the precip-
          itation reaction and subsequent settling  (Figure
          7-4 details the solubilities of various metalhydroxides
          as a function of pH).

     3.   Effective removal of precipitated solids (see
          appropriate solids removal technologies).

If the treatment chemicals are not present in slight excess concen-
trations, some metals will remain dissolved in the waste stream.

Advantages and Limitations

Hydroxide precipitation has proven to be an effective technique
for removing many pollutants from industrial wastewater.  It
operates at ambient conditions and is well suited to automatic
control.  Lime is usually added as a slurry when used in hy-
droxide precipitation.  The slurry must be kept well mixed and
the addition lines periodically checked to prevent blocking,
which may result from a buildup of solids.  The use of hydroxide
precipitation does produce large quantities of sludge requiring
disposal following precipitation and settling.  The use of treat-
ment chemicals requires caution because of the potentially
hazardous situation involved with the storage and handling of
those chemicals.  Recovery of  the precipitated species is some-
times difficult because of the homogeneous nature of most
hydroxide sludges (where no single metal hydroxide is present
in high concentrations) and because of the difficulty in smelt-
ing which results from the interference of calcium compounds.
                             VTI-12

-------
        100
xi
3
      0.001
     0.0001
       0.01
                                              10       11
12
                                   pH






                            FIGURE 7-4




     SOLUBILITIES OF METAL HYDROXIDES AS A FUNCTION  OF  pH




                              VII-13

-------
Operational Factors

Reliability;  The reliability of hydroxide precipitation  is high,
although proper monitoring, control, and pretreatment to  remove
interfering substances is required.

Maintainability;  The major maintenance needs involve periodic
upkeep of monitoring equipment, automatic feeding equipment,
mixing equipment, and other hardware.  Removal of accumulated
sludge is necessary for efficient operation of precipitation/
sedimentation systems.

Solid Waste Aspects;  Solids which precipitate out are removed
in a subsequent treatment step.  Ultimately, the solids must be
properly disposed of.  Proper disposal practices are discussed
later in this section under Treatment of Sludges.

Demonstration Status

Hydroxide precipitation of metals is a classic waste treatment
technology used by most industrial waste treatment systems.
As noted earlier, sedimentation to remove precipitates is dis-
cussed separately; however, both techniques have been illustrated
in Figure 7-3.

SEDIMENTATION

Sedimentation is a process which removes solid particles  from a
liquid waste stream by gravitational force.  The operation is
effected by reducing the velocity of the feed stream in a large
volume tank or lagoon so that gravitational settling can  occur.
Figure 7-5 shows two typical sedimentation devices.

For the Option 1 system, sedimentation is preceded by hydroxide
precipitation which converts dissolved metallic pollutants to
solid forms and coagulates suspended precipitates into larger,
faster settling particles.  Wastewater is fed into a high volume
tank or lagoon where it loses velocity and the suspended  solids
are allowed to settle out.  High retention times are generally
required (the plants in the data base used retention times ran-
ging from 1 to 48 hours).  Accumulated sludge can be collected
and removed either periodically or continuously and either man-
ually or mechanically.
                                VI1-14

-------
Sedimentation Basin

          Inlet Zone



Inlet Liquid
  Baffles To Maintain
'Quiescent Conditions
Settled Particles Collected
 And Periodically Removed
 Circular Clarifier
        linS Partfcle-Trajfct<5ry••.
Outlet Zone
                                                                                         Outlet Liquid
                          Belt-Type Solids Collection Mechanism
                               Inlet Liquid
                    Circular Baffle

                             Annular Overflow Weir

                       T-i|t	
                                     Outlet Liquid
           Settling Zone"
             Revolving Collection
                Mechanism
                               Settled Particles
             (Collected And Periodically Removed ) J sludge Drawoff
                                                                             Settling Particles
                                              FIGURE   7-5

                              REPRESENTATIVE  TYPES  OF SEDIMENTATION
                                               VII-15

-------
Inorganic coagulants or polyelectrolytic flocculants are added
to enhance coagulation.  Common inorganic coagulants include
sodium sulfate, sodium aluminate, ferrous or ferric sulfate, and
ferric chloride.  Organic polyelectrolytes vary in structure,
but all usually form larger floccules than coagulants used alone.

The use of a clarifier for sedimentation reduces space requirements,
reduces retention time, and increases solids removal efficiency.
Conventional clarifiers generally consist of a circular or rec-
tangular tank with a mechanical sludge collecting device or with
a sloping funnel-shaped bottom designed for sludge collection.
In advanced clarifiers, inclined plates, slanted tubes, or a
lamellar network may be included within the clarifier tank in
order to increase the effective settling area.  A more recently
developed "clarifier" utilizes centrifugal force rather than
gravity to effect the separation of solids from a liquid.  The
precipitates are forced outward and accumulate against an outer
wall, where they can later be collected.  A fraction of the sludge
stream is often recirculated to the clarifier inlet, promoting
formation of a denser sludge.

Application

Sedimentation is used in metal finishing to remove precipitated
metals, phosphates, and suspended solids.  Because most metal
ion pollutants are easily converted to solid metal hydroxide
precipitates, sedimentation is of particular use in industries
associated with metal finishing and in other industries with high
concentrations of metal ions in their wastes.  In addition to
heavy metals, suitably precipitated materials effectively removed
by sedimentation/clarification include aluminum, manganese, cobalt,
arsenic, antimony, beryllium, molybdenum, fluoride, and phos-
phate .

A properly operating sedimentation system is capable of efficient
removal of suspended solids, precipitated metal hydroxides, and
other impurities from wastewater.  The performance of the process
depends on a variety of factors, including the effective charge on
the suspended particles (adjustments can be made in the type and
dosage of flocculant or coagulant) and the types of chemicals
used in prior treatment.  It has been found that the site of floc-
culant or coagulant addition may significantly influence the
effectiveness of sedimentation.  If the flocculant is subjected
to too much mixing before entering the settling device, the
agglomerated complexes may be broken up and the settling effec-
tiveness diminished.  At the same time, the flocculant must
have sufficient mixing in order for effective set-up and settling
to occur.  Most plant personnel select the line or trough leading
into the clarifier as the most efficient site for flocculant
addition.  The performance of sedimentation is a function of the
                                VI1-16

-------
retention time, particle size and density/ and the surface area of
the sedimentation catchment.

Sampling visit data from plant 40063, a metal finishing and por-
celain enameling facility, exemplify efficient operation of a
chemical precipitation/settling system.  The following table pre-
sents sampling data from this system, which consists of the addition
of lime and caustic soda for pH adjustment and hydroxide precipita-
tion, polyelectrolyte flocculant addition, and clarification.  Sam-
ples were taken of the raw waste influent to the system and of the
clarifier effluent.  Flow through the system is approximately
18,900 LPH (5000 GPH).  Concentrations are given in mg/1.  The ef-
fluent pH shown in the table reflects readjustment with sulfuric
acid after solids removal.  Parameters which were not detected are
listed as ND.


pH Range
TSS
Al
Co
Cu
Fe
Mn
Ni
Se
Ti
Zn
Day
Inf.
9.2-9.6
4390
37.3
3.92
0.65
137
175
6.86
28.6
143
18.5
1
Eff .
8.3-9.8
9.0
0.35
ND
0.003
0.49
0.12
ND
ND
ND
0.027

Inf.
9.2
3595
38.1
4.65
0.63
110
205
5.84
30.2
125
16.2
Day 2
Eff.
7.6-8.1
13
0.35
ND
0.003
0.57
0.012
ND
ND
ND
0.044

Inf.
9.6
2805
29.9
4.37
0.72
208
245
5.63
27.4
115
17.0
Day 3
Eff.
7.8-8.2
13
0.35
ND
0.003
0.58
0.12
ND
ND
ND
0.01
TSS levels were below 15 mg/1 on each day, despite average raw
waste TSS concentrations of over 2800 mg/1.  Effluent pH was main-
tained at approximately 8 or above, lime addition was sufficient
to precipitate most of the dissolved metal ions, and the floccu-
lant addition and clarifier retention served to effectively remove
the precipitated solids.
                              VII-17

-------
Advantages and Limitations

The major advantage of simple sedimentation is the simplicity of
the process itself - the gravitational settling of solid parti-
culate waste in a holding tank or lagoon.  The major disadvantage
of sedimentation involves the long retention times necessary to
achieve complete settling, especially if the specific gravity
of the suspended matter is close to that of water.

A clarifier is more effective in removing slow settling suspended
matter in a shorter time and in less space than a simple sedimen-
tation system.  Also, effluent quality is often better from a
clarifier.  The cost of installing and maintaining a clarifier is,
however, substantially greater than the costs associated with
sedimentation lagoons.

Inclined plate, slant tube, and lamellar clarifiers have even
higher removal efficiencies than conventional clarifiers, and
greater capacities per unit area are possible.  Installed costs
for these advanced clarification systems are claimed to be one
half the cost of conventional systems of similar capacity.

Operational Factors

Reliability;  Sedimentation is a highly reliable technology for
removing suspended solids and precipitates.  Proper treatment
of the wastewater prior to sedimentation (precipitation and coagu-
lant addition) is essential for continued efficient operation.
Those advanced clarifiers using slanted tubes, inclined plates,
or a lamellar network may require pre-screening of the waste in
order to eliminate any fibrous materials which could potentially
clog the system.

Maintainability;  When clarifiers are used, the associated system
utilized for chemical pretreatment and sludge dragout must be
maintained on a regular basis.  Routine maintenance of mechanical
parts is also necessary-  If lagoons are used, little maintenance
is required other than periodic sludge removal.

Solid Waste Aspects;  Rather large quantities of sludge are generated
and can be dewatered to facilitate handling.  Further appropriate
disposal is required (see Treatment of Sludges).

Demonstration Status

Sedimentation in conjunction with hydroxide precipitation (the
Option 1 system) represents the typical method of solids removal
and is employed extensively in industrial waste treatment.  The
advanced clarifiers are just beginning to appear in significant
numbers in commercial applications, while the centrifugal force
                               VI1-18

-------
"clarifier" has yet to be used commercially.  Sedimentation pre-
ceded by hydroxide precipitation is used in 103 plants in the
Metal Finishing data base and these are shown in Table 7-3.

Common Metals Waste Treatment System Performance - Option 1^

Performance of a properly operating Option 1 treatment system
(shown in Figure 7-6 with its sources of wastes) is demonstrated
by effective solids settling, which is indicated by low effluent
levels of total suspended solids (TSS).  Effective solids set-
tling depends upon maintaining the system pH at the level needed
to form metal hydroxides.  Generally a pH range of 8.5 to 9.5
is considered optimum for hydroxide precipitation with mixed
metal wastes.

To establish the Option 1 treatment system performance character-
istics, plants employing Option 1 treatment that were visited
were selected from the metal finishing data base.  The files
for these plants were then examined to ensure that only properly
operating facilities were included in the performance data base
by establishing criteria to eliminate the data for improperly
operating systems.  The criteria for eliminating improperly
operating treatment systems were as follows:

1.   Data with an effluent TSS level greater than 50 mg/1 were
     deleted.  This represents a level of TSS above which no
     well-operated treatment plant should be discharging.
     Figure 7-7 shows effluent TSS concentrations vs. per-
     centile distribution.  As is shown in the graph there is
     an abrupt increase in slope (approximately 5.8:1) at the
     50 mg/1 level.  Deleting data above this concentration
     still includes nearly seventy percent of the data base.
     The following presentation of TSS and metals concentrations
     for plants 20073 and 20083 shows that a low level of TSS
     is indicative of low effluent metal concentrations.

                         Plant ID 20073 (mg/1)

               Day 1               Day 2

          Inf.      Eff.      Inf.      Eff.

TSS       702.      11.       712.      14        124.      33.
Cu        64.6      .812      97.1      .875      91.2      1.37
Ni        53.8      .448      52.5      .478      89.7      1.12
Cr        162.      1.47      175.      1.89      220.      2.85
                              VII-19

-------
                     TABLE 7-3
METAL FINISHING PLANTS WITH OPTION 1 TREATMENT  SYSTEMS
                 FOR COMMON METALS
    (Hydroxide Precipitation with Sedimentation)
 01003
 02032
 02037
 04065
 04069
 04071
 04132
 04148
 04174
 04205
 04211
 04273
 05020
 05021
 06002
 06006
 06035
 06037
 06051
 06065
 06073
 06074
 06075
 06077
 06079
 06083
 06084
 06086
 06087
 06090
06110
06124
06731
09026
10020
11008
11113
11477
12014
12061
12071
12074
12076
12087
12102
15010
15070
16544
17061
19050
19063
19067
19068
19098
20005
20022
20070
20073
20077
20078
20079
20083
20086
20120
20159
20162
20255
21078
23041
23061
27044
27045
28125
30022
31020
31037
33024
33050
33065
33074
33113
33120
33172
33184
33186
33199
33692
34036
36040
36041
36062
36112
36176
36623
38031
38050
40062
40079
43052
44036
44037
44050
44062
                          VI1-20

-------
Sludge-
Complexed
Metals
Wastes
1
Solids
Removal
t
Discharge
O
Chromium Com
Bearing Cyanide Mefc
Wastes Wastes Was
t t
Hexavalent Cyanide
Chromium Oxidation
Reduction
i i
1
mon Precious
als Metals
tes Wastes
*
Precious
Metals
Recovery


i
i Precipitation
Recovered
-^- Metals
"1
1
1
                                                 Sed imentat ion
                                       _ __ J	i	1	|
Sludge
                                                   Discharge
                                  FIGURE  7-6
                     TREATMENT OF COMMON METALS WASTES
                                   OPTION 1

-------
 180
160
140
120
100
 80
 60
 40
 20
               10
                            20
                                         30
     40           50
 Percentile Distribution
       FIGURE 7-7

CLARIFIER TSS DISTRIBUTION
                                                                               60
                                                                                           70
                                                                                                        80
                                                                                                                     90

-------
                         Plant ID  20083  (mg/1)

        Day 1           Day 2            Day  3            Day 4

     Inf.    Eff.    Inf.    Eff.     Inf.    Eff.     Inf.    Eff.
TSS
Cu
Ni
24.0
56.2
103
145
2.75
6.13
18.0
57.7
153
23.0
0.38
0.91
15.0
39.3
82.8
27.0
0.21
0.77
10.0
50.0
87.1
97.0
2.44
4.75
2.   Plants with alkaline precipitation systems  that operated  at
     an average effluent pH of less than 7.0 were deleted.   An
     alkaline precipitation system will not work properly  in
     this pH range, as is illustrated by the following data  from
     plant 21066.

                         Plant ID 21066 (mg/1)

                         Day 1                    Day 2

                    Inf.      Eff.           Inf.      Eff.

Avg. effluent pH    NA        5.4            NA        5.1
TSS                 48.0      448            61.0      371
Cr                  5.36      3.74           8.99      1.28
Zn                  114       150            111       140

Proper control of pH is absolutely essential for favorable perfor-
mance of precipitation/sedimentation technologies.  This is  illus-
trated by results obtained from a sampling visit to manufacturing
plant 47432 (not a metal finishing plant) as shown in the  follow-
ing table (concentrations are in mg/1):


          In

pH Range  2.4-3.4

TSS       39

Copper    312

Zinc      250

Lead      0.16

Nickel    42.8
Day

.4





1
Out
8.5-8.7
8
0.22
0.31
0.03
0.78
Day
In
1.0-3.0
16
120
32.5
0.16
33.8
2
Out
5.0-6.0
19
5.12
25
0.04
0.53
Day
In
2.0-5.0
16
107
43.8
0.15
36.6
3
Out
6.5-8.1
7
0.66
0.66
0.04
0.46
                               VII-23

-------
This plant utilizes lime precipitation and pH adjustment  followed
by flocculant addition and sedimentation.  Samples were taken  be-
fore and after the system.  On day two effluent pH was allowed to
range below 7 for the entire day and the effluent metals  control
was less effective than on days one and three.  In general, better
results will be obtained in chemical precipitation systems when pH
is maintained consistently at a level between 8.5 and 9.5.  It can
be clearly seen that the best results were produced on day one when
the effluent pH was kept within the recommended range for the  entire
day-

3.   Plants which had effluent flows significantly greater than
     the corresponding raw waste flows were deleted.  The in-
     crease in flows was assumed to be dilution by other  waste-
     waters.

4.   Plants that experienced difficulties in system operation
     during the sampling period were excluded.  These difficulties
     included a few hours operation at very low pH (<4.0)f
     observed operator error,an inoperative chemical feed system,
     improper chemical usage, improperly maintained equipment,
     high flow slugs during the sampling period, and excessive
     surface water intrusion (heavy rains).

The following procedure was followed for each metal pollutant  para-
meter in order to eliminate spurious background metal readings.
The mean effluent concentration of each parameter was calculated
and when a raw waste concentration was less than the mean effluent
concentration for that parameter, the corresponding effluent reading
was deleted from the data set.  The mean was recalculated using
points not removed initially and the process was repeated in an in-
terative loop.  The deletion of these points prevents the calcula-
tion of unrealistically low effluent concentrations from  the waste
treatment systems due to low raw waste pollutant loadings.

Plots of raw waste concentration vs. effluent concentration were
generated for total suspended solids, caduium, total chromium,
copper, iron, lead, nickel, zinc, and fluorides.  These plots
are shown in Figures 7-8 through 7-16.  The mean effluent
concentrations for these parameters were then computed and are
presented in Table 7-4.
                             VII-24

-------
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-------
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                                                        FIGURE 7-10
                               EFFLUENT CHROMIUM CONCENTRATIONS  vs  RAW WASTE CONCENTRATIONS

                                                         OPTION  1

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                                                             FIGURE  7-11


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                                                              OPTION 1

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                                              FIGURE  7-13

                       EFFLUENT  LEAD CONCENTRATIONS  vs RAW WASTE CONCENTRATIONS
                                               OPTION 1

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                                                        OPTION  1

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                                                       FIGURE  7-15


                                 EFFLUENT ZINC CONCENTRATIONS  VS  RAW WASTE CONCENTRATIONS
                                                        OPTION 1

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                             EFFLUENT FLUORIDES CONCENTRATIONS vs RAW WASTE CONCENTRATIONS

                                                       OPTION 1

-------
                         TABLE 7-4
                 TREATMENT OF COMMON METALS
           OPTION !_ MEAN EFFLUENT CONCENTRATIONS

               Parameter                     mg/1

          Total Suspended Solids             17.8
          Cadmium                            .012
          Chromium, Total                    .572
          Copper                             .814
          Iron                               .797
          Lead                               .050
          Nickel                             .942
          Zinc                               .551
          Fluorides                          15.3

Table 7-5 presents the values for daily and 30-day average maximum
variability factors that were established for the Electroplating
Category.  The derivation and development of these are reported
in detail in the Development Document for Existing Source Pretreat-
ment Standards for the Electroplating Point Source Category
(EPA 440/ 1-79/003, August 1979).  These values were used in
conjunction with the mean effluent concentrations tabulated in
Table 7-4, to establish the daily maximum and 30 day average
concentrations presented in Table 7-6 for the Option 1 treatment
of common metals.

                           TABLE 7-5
               SUMMARY OF DAILY AND 30-DAY AVERAGE
                   MAXIMUM VARIABILITY FACTORS

                                       Variability Factor

    Pollutant                      Daily Max.      30-Day-Avg. Max.

Total Suspended Solids*                 2.9            1.3
Cyanide, Total                          5.0            1.5
Cyanide, Amenable                       5.0            1.5
Cadmium                                 2.9            1.3
Chromium, Total                         3.9            1.4
Chromium, Hexavalent                    5.2            1.5
Copper                                  3.2            1.3
Iron*                                   2.9            1.3
Lead                                    2.9            1.3
Nickel                                  2.9            1.3
Zinc                                    3.0            1.3
Silver                                  2.9            1.3
Fluorides*                              2.9            1.3
Oil and Grease*                         2.9            1.3
Total Priority Organics                 2.9            1.3

*Minimum variability factor selected; further effort needed to
 establish final value.
                             VU-34

-------
                           TABLE 7-6
         OPTION 1 COMMON METAL SUBCATEGORY CONCENTRATIONS
                                       Concentration  (mg/1)
    Pollutant

      Total Suspended Solids
(118) Cadmium
(119) Chromium
(120) Copper
      Iron
(122) Lead
(124) Nickel
(128) Zinc
      Fluorides
Daily Max.

     51.6
     0.04
     2.23
     2.61
     2.31
     0.15
     2.73
     1.65
     44.4
30-Day-Ave.

    23.1
    0.02
    0.80
    1.06
    1.04
    0.07
    1.23
    0.72
    19.9
The data collection portfolios (DCP's) received from non-visited
facilites were also sorted for plants which have an Option 1
common metals treatment system.  Of these plants, fifty reported
effluent concentration data.  The raw waste data were very
fragmented and could not be correlated with the effluent data.
Consequently, only effluent concentration statistics were generated
and the percentile distribution for these effluent concentrations
are presented in Figures 7-17 through 7-25.  Because these plants
were not visited, it is not possible to know which plants were
not operating properly and should be deleted.  The Option 1 daily
maximum concentrations that were presented in Table 7-10 are over-
layed onto these distribution plots for direct comparison of the
visited plant sampling data with these DCP data.

Figures 7-26 through 7-34 present effluent concentrations for the
entire metal finishing data base.  The graphs include all data points
that were removed during the determination of the pollutant mean
effluent concentrations for a properly operating treatment system.
Data are presented for the eight pollutants that were selected
for limitation in the Common Metals Subcategory and the daily maxi-
mum concentration for each pollutant is overlayed for comparison.
Table 7-7 summarizes the percentage of the metal finishing data
base that is in compliance with the daily maximum concentration
limitation for the sampled plants after the deletions were made
as discussed above, the entire sampled data base, and the DCP
data base.  Table 7-3 already presented a listing of plants from
the metal finishing data base which have an Option 1 common me-
tals treatment system.  This includes both sampled and DCP plants.
                              VI1-35

-------
  280CH
  2400-
  2000-
c
0
a
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O
CO
  1600-
  1200-
CO
D
CO
(0
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O
   800-
    400-
              Daily Maximum
03 01
                                 tgtg
20         40          60

     Percentile  Distribution
                                                 80
          100
                           FIGURE  7-17


             DCP  DATA FOR TSS EFFLUENT DISTRIBUTION
                             OPTION 1
                               VI1-36

-------
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                                        Daily Maximum
                                                                                 a
                                   10
                           20
                                      30
40         50         60

Percentile  Distribution
70
80
                                                                                                                       90
                                                                       FIGURE 7-18


                                                       DCP  DATA  FOR CADMIUM EFFLUENT DISTRIBUTION

                                                                         OPTION  1

-------
  12-
  10-


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                   Percentile Distribution
                      FIGURE 7-19



     DCP  DATA  FOR CHROMIUM EFFLUENT DISTRIBUTION

                        OPTION 1
                           VII-38

-------
  14 i
  12-
  10-
   8-
c


-------
   6-
  5 -
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                                                     a
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           Daily Maximum
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              20         40        60         80

                   Percentile Distribution
                      100
                         FIGURE 7- 21


          DCP DATA FOR  IRON EFFLUENT DISTRIBUTION

                           OPTION 1
                              VI1-40

-------
   1.75-,
  1.50-
  1.25-
5 1.00-


4J
c
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  0.75-
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   0.50-
  0.25-
                  Daily Maximum
                    a      m
                                                                  n      a
                                                     n
                 10
                            20
                                      30
 40         50        60         70
Percentile Distribution
                                                                                           80
90
                                                   FIGURE 7-22

                                    DCP DATA FOR  LEAD EFFLUENT DISTRIBUTION
                                                     OPTION 1

-------
  12-
  10-
~  8

c

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   6-
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                                                    E
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             Daily Maximum                           QJ
                                             _
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    0         20         40        60         80         100

                   Percentile Distribution
                         FIGURE 7-23


         DCP DATA  FOR NICKEL EFFLUENT  DISTRIBUTION
                           OPTION 1
                              VI1-42

-------
   28-1
   24^
   20n
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en
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             Daily Maximum
                                     CD
                                                      m
20        40         60         80

     Percentile Distribution
                                                         100
                          FIGURE 7-24


           DCP DATA  FOR ZINC EFFLUENT DISTRIBUTION
                            OPTION  1
                              VII-43

-------
                         70n
                         60-
                                                                                              CQ
S
M
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                         50-
                      cn
                         40-
30-
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                        20-
                         10-
                                               Daily Maximum
                                                             GJ
                           24
                                     32
                       40
48        56         64

    Percentile Distribution
                                                                                          72
                                                                                                     80
                                                                                       88
                                                                                                 96
                                                                  FIGURE 7-25



                                                 DCP DATA  FOR FLUORIDES EFFLUENT DISTRIBUTION

                                                                    OPTION  1

-------
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      10
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                                                                                                  10
                                  Total Suspended Solids  Raw  Waste (mg/1)


                                                           (Entire Metal  Finishing Category Data Base)



                                                FIGURE  7-26

                          EFFLUENT  TSS CONCENTRATIONS vs RAW WASTE  CONCENTRATIONS
                                                  OPTION  1

-------
s
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                                       Chromium Raw  Waste (mg/1)
                                                          (Entire Metal  Finishing Category Data Base)
                                             FIGURE 7-28
                    EFFLUENT CHROMIUM CONCENTRATIONS  vs  RAW WASTE CONCENTRATIONS

                                              OPTION  1

-------
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                                                   10
                 100
1000
                                          Copper  Raw  Waste (rag/1)



                                                           (Entire Metal  Finishing Category Data  Base)
                                             FIGURE 7-29



                      EFFLUENT COPPER CONCENTRATIONS  vs RAW WASTE CONCENTRATIONS

                                               OPTION  1

-------
   28
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c 12
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                       1.0
                                                                              10-
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10                100


Iron Raw Waste (mg/1)


                  (Entire  Metal  Finishing Category Data Base)
                                              FIGURE  7-30


                         EFFLUENT IRON CONCENTRATIONS vs RAW WASTE CONCENTRATIONS

                                                OPTION 1

-------
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                                  0.1                            1.0                             10

                                        Lead  Raw Waste (mg/1)

                                                           (Entire  Metal Finishing Category  Data Base)
                                                        FIGURE  7-31


                                  EFFLUENT  LEAD CONCENTRATIONS vs RAW WASTE CONCENTRATIONS
                                                          OPTION 1

-------
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                                   10                            100

                                       Nickel Raw Waste  (mg/1)
1000
                                                          (Entire Metal Finishing Category Data  Base)
                                           FIGURE  7-32
                    EFFLUENT NICKEL CONCENTRATIONS  vs  RAW WASTE CONCENTRATIONS

                                            OPTION  1

-------
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                                                                                    100
                                                                                                 1000
                                                   Zinc Raw Waste (mg/1)


                                                                    (Entire Metal Finishing Category Data Base)




                                                        FIGURE 7-33

                                  EFFLUENT  ZINC  CONCENTRATIONS VS RAW WASTE CONCENTRATIONS
                                                          OPTION 1

-------
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                                       Fluorides Raw Waste  (mg/1)
                                                                                                 1000
                                                          (Entire  Metal Finishing Category Data Base)
                                              FIGURE 7-34
                     EFFLUENT FLUORIDES CONCENTRATIONS vs  RAW WASTE CONCENTRATIONS

                                               OPTION 1

-------
                         TABLE 7-7
          PERCENTAGE OF MFC DATA BASE BELOW THE DAILY
          MAXIMUM CONCENTRATION LIMITATION FOR OPTION  1  (%)
Pollutant

Cadmium
Chromium, Total
Copper
Iron
Lead
Nickel
Zinc
Fluorides
Sampled Plants
After Deletions

     96.8
     97.3
     93.8
     92.0
     93.3
     95.5
     93.7
    100.0
All Sampled
  Plants

   88.0
   86.5
   79.4
   82.2
   79.3
   83.0
   74.7
   98.1
DCP Data Base

     50.0
     94.8
     91.9
     70.3
     53.3
     90.3
     89.4
     66.6
TREATMENT OF COMMON METALS WASTES - OPTION _2
The Option 2 treatment system for common metals wastes  is pictured
schematically in Figure 7-35.  As shown in the figure,  the  system
is identical to the Option 1 treatment system with'the  addition of
filtration devices after the primary solids removal devices.  The
purpose of these filtration units is to "polish" the effluent, that
is, remove suspended solids such as metal hydroxides which  did not
settle out in the clarifiers.  The filters also act as  a safeguard
against pollutant discharge if an upset should occur in the sedi-
mentation device.  Filtration techniques that are applicable  for
Option 2 systems include diatomaceous earth filtration  and  granular
bed filtration.

DIATOMACEOUS EARTH FILTRATION

Diatomaceous earth filtration, combined with precipitation  and
sedimentation, is a solids separation device which can  further
enhance suspended solids removal.  The diatomaceous earth filter
is used to remove metal hydroxides and other solids from the
wastewater and provides an effluent of high quality.  A diatoma-
ceous earth filter is comprised of a filter element, a  filter
housing and associated pumping equipment.  The filter element con-
sists of multiple peat screens which are coated with diatomaceous
earth.  The size of the filter is a function of flow rate and de-
sired operating time between filter cleanings.

Normal operation of the system involves pumping a mixture of  dia-
tomaceous earth and water through the screen leaves.  This  depo-
sits the diatomaceous earth filter media on the screens and pre-
pares them for treatment of the wastewater.  Once the screens are
completely coated, the pH adjusted wastewater can be pumped through
the filter.  The metal hydroxides and other suspended solids  are
                              VI1-54

-------
       Sludge-
       Sludge-
U1
en
Complexed
Metals
Wastes
t
Solids
Removal
t
Filtration
1
Discharge
Chromium Com
Bearing Cyanide Met
Wastes Wastes Was
1 t
Hexavalent Cyanide
Chromium Oxidation
Keduction ' '
i

iron Precious
als Metals
tes Wastes
t
Precious
Metals
Recovery

1
Precipitation 1
1
Recovered
-^- Metals
Sludge
                                             Sludge
                                                      Sedimentation
                                                                       Option  2  System
            Filtration
                                            i	_,__
                                                        Discharge
                                     FIGURE  7-35
                         TREATMENT OF  COMMON METALS WASTES

                                       OPTION 2

-------
removed from the effluent in the diatomaceous earth  filter.   The
buildup of solids in the filter increases the pressure  drop  across
the filter.  At a certain pressure, the wastewater  is stopped,
the filter is cleaned and the cycle is restarted.

Advantages and Limitations

The principal advantage to using a diatomaceous  earth filter its
increased removal of suspended solids and precipitates.   One
additional advantage is the sludge removed from  the  filter is
much drier than that removed from a clarifier (approximately 50%
solids).  This high solids content can significantly reduce  the
cost of hauling and landfill.

The major disadvantage to the use of a filter system is  an increase
in operation and maintenance costs.  In some cases this  increase
in O & M costs is offset by the lower investment costs  required
when not investing in land and outside construction.

Specific Performance

Three of the plants that were visited and sampled were  operating
diatomaceous earth filters.  The analytical results  of  samples
taken before and after the filters are displayed below.


                   Plant ID 09026 (mg/1)

                  Day 1              Day 2                Day 3

           Input To  Filter    Input To  Filter    Input To   Filter
Parameter   Filter   Effluent   Filter   Effluent    Filter    Effluent

TSS         548.      11.       544.      15         450       67
Cu          52.4      2.25      63.8      4.17       63.8     2.2
Ni          .299      .116      .341      .102       .377      .107
Crf Total   .078      .008      .086      .01        .086      .012
Zn          22.4      3.06      27.6      .706       30.6      .882
Cd          .011      .012      .01       .009       .011      .011
Sn          .086      .086      .086      .086       .086      .086
Pb          .062      .036      .062      .04        .065      .051
                             VI1-56

-------
                   Plant ID 36041 (mg/1)
               Day 1
                    Day 2
                         Day 3
          Input To  Filter    Input To  Filter    Input To  Filter
Parameter  Filter   Effluent   Filter   Effluent   Filter   Effluent
TSS
Cu
Ni
Cu, Total
Zn
Cd
Sn
Pb
1036
26.5
5.0
28.6
18.7
.053
1.77
1.00
                      32.
                      1.89
                      .32
                      .667
                      .765
                      .009
                      .171
                      .064
                 524.
                 7.53
                 2.57
                 12.2
                 13.4
                 .042
                 2.0
                 .136
            10.
            .444
            .044
            .611
            .139
            .006
            .143
            .032
       652.
       9.56
       4.49
       25.0
       14.3
       .042
       1.58
       .212
  5.
  1.06
  .571
  .333
  .430
  .006
  .114
  .036
                   Plant ID 38217 (mg/1)
Parameter

TSS
Cu
Ni
Cr, Total
Zn
Cd
Sn
Pb
Input To
 Filter

  575.
  .158
  .253
  .022
  1.92
  .006
  .028
  .058
Filter
Effluent

  30.
  .261
  .195
  .037
  3.79
  .011
  .034
  .154
Demonstration Status
Input To
 Filter

  620.
  .325
  .255
  .060
  5.20
  .019
  .054
  .150
Filter
Effluent

  90.
  .085
  .159
  .020
  2.31
  .010
  .003
  .032
Filters with similar operational characteristics to that described
above are in common use throughout the metal finishing  industry.

GRANULAR BED FILTRATION

Filtration is basic to water treatment technology, and  experience
with the process dates back to the 1800's.  Filtration  occurs  in
nature as the surface ground waters are purified by sand.  Silica
sand, anthracite coal, and garnet are common filter media used  in
water treatment plants.  These are usually supported by gravel.
The media may be used singly or in combination.  The multi-media
filters may be arranged to maintain relatively distinct layers
by virtue of balancing the forces of gravity, flow and  buoyancy
on the individual particles.  This is accomplished by selecting
appropriate filter flow rates (gpm/sq ft), media grain  size, and
density.
                             VII-57

-------
Granular bed filters may be classified  in  terms  of filtration rate,
Filter media, flow pattern, or method of pressurization.   Tradition-
al rate classifications are slow sand,  rapid  sand, and high rate
mixed media.  In the slow sand filter,  flux or hydraulic  loading
is relatively low,and removal of collected solids  to clean the
filter is therefore relatively infrequent. The  filter is often
cleaned by scraping off the inlet  face  (top)  of  the sand  bed.  In
the higher rate filters, cleaning  is frequent and  is accomplished
by a periodic backwash, opposite to the direction  of normal flow.

A filter may use a single medium such as sand or diatomaceous
earth, but dual and mixed (multiple) media filters allow  higher
flow rates and efficiencies.  The  dual media  filter usually
consists of a fine bed of sand under a coarser bed of anthracite
coal.  The coarse coal removes most of the influent solids,
while the fine sand performs a polishing function.  At the end
of the backwash, the fine sand settles to  the bottom because it
is denser than the coal, and the filter is ready for normal
operation.  The mixed media filter operates on the same principle,
with the finer, denser media at the bottom and the coarser, less
dense media at the top.  The usual arrangement is  garnet  at the
bottom (outlet end) of the bed, sand in the middle,  and anthracite
coal at the top.  Some mixing of these layers occurs and  is, in
fact, desirable.

The flow pattern is usually top-to-bottom, but other patterns
are sometimes used.  Upflow filters are sometimes  used, and in a
horizontal filter the flow is horizontal.  In a  biflow filter, the
influent enters both the top and the bottom and  exits laterally.
The advantage of an upflow filter  is that  with an  upflow  backwash
the particles of a single filter medium are distributed and main-
tained in the desired coarse-to-fine (bottom-to-top)  arrangement.
The disadvantage is that the bed tends to  become fluidized, which
ruins filtration efficiency.  The biflow design  is an attempt to
overcome this problem.

The usual granular bed filter operates by  gravity  flow.  However,
pressure filters are also used.  Pressure  filters  permit  higher
solids loadings before cleaning and are advantageous when the
filter effluent must be pressurized for further  downstream treat-
ment.  In addition, pressure filter systems are  often less costly
for low to moderate flow rates.

Figure 7-36 depicts a granular bed filter.  It is  a  high  rate,
dual media, gravity downflow filter, with  self-stored backwash.
Both filtrate and backwash are piped around the  bed  in an arrangement
that permits upflow of the backwash, with  the stored filtrate serving
as backwash.  Addition of the indicated coagulant  and polyelectrolyte
usually results in a substantial improvement  in  filter performance.
                             VI1-58

-------
                                            INFLUENT
COMPARTMENT \ MEDIA
0 COLLECTION CHAMBER
                               DRAIN
             FIGURE 7-36




  GRANULAR BED FILTRATION EXAMPLE
                VII-59

-------
Auxiliary filter cleaning is sometimes employed  in the  upper  few
inches of filter beds.  This is conventionally referred  to  as
surface wash and is accomplished by water jets just below the
surface of the expanded bed during the backwash  cycle.   These
jets enhance the scouring action in the bed by increasing the
agitation.

An important feature for successful filtration and backwashing
is the underdrain.  This is the support structure for the
bed.  The underdrain provides an area for collection of  the filtered
water without clogging from either the filtered  solids  or the media
grains.  In addition, the underdrain prevents loss of the media
with the water, and during the backwash cycle it provides even
flow distribution over the bed.  Failure to dissipate the velocity
head during the filter or backwash cycle will result in  bed upset
and the need for major repairs.

Several standard approaches are employed for filter underdrains.
The simplest one consists of a parallel porous pipe imbedded
under a layer of coarse gravel and manifolded to a header pipe
for effluent removal.  Other approaches to the underdrain
system are known as the Leopold and Wheeler filter bottoms.
Both of these incorporate false concrete bottoms with specific
porosity configurations to provide drainage and  velocity head
dissipation.

Filter system operation may be manual or automatic.  The filter
backwash cycle may be on a timed basis, a pressure drop  basis with
a terminal value which triggers backwash, or a solids carry-
over basis from turbidity monitoring of the outlet stream.  All
of these schemes have been successfully used.

Application and Performance

Granular bed filters are used in metal finishing to remove  residual
solids from clarifier effluent.  Filters in wastewater  treatment
plants are often employed for polishing following sedimentation
or other similar operations.  Granular bed filtration thus  has
potential application to nearly all industrial plants.   Chemical
additives which enhance the upstream treatment equipment may
or may not be compatible with or enhance the filtration  process.
It should be borne in mind that in the overall treatment system,
effectiveness and efficiency are the objectives, not the performance
of any single unit.  The volumetric fluxes for various  types  of
filters are as follows:
     Slow Sand
     Rapid Sand
     High Rate Mixed Media
 2.04 - 5.30 1/min/sq m
40.74 - 51.48 1/min/sq m
81.48 - 122.22 1/min/sq m
                              VI1-60

-------
Suspended solids are commonly removed from wastewater streams by
filtering through a deep 0.3-0.9 m (1-3 feet) granular filter bed.
The porous bed formed by the granular media can be designed  to
remove practically all suspended particles.  Even colloidal
suspensions (roughly 1 to 100 microns) are adsorbed on the surface
of the media grains as they pass in close proximity in the narrow
bed passages.

Properly operating filters following some pretreatment to reduce
suspended solids well below 200 mg/1 should produce water with
less than 10 mg/1 TSS.  Pretreatment with inorganic or polymeric
coagulants can improve poor performance.

Advantages and Limitations

The principal advantages of granular bed filtration are its
low initial and operating costs and reduced land requirements
over other methods to achieve the same level of solids removal.
However, the filter may require pretreatment if the solids level
is high (from 100 to 150 mg/1).  Operator training is fairly high
due to controls and periodic backwashing, and backwash must  be
stored and dewatered to be disposed of economically.

Operational Factors

Reliability;  The recent improvements in filter technology have
significantly improved filtration reliability.  Control systems,
improved designs, and good operating procedures have made filtration
a highly reliable method of water treatment.

Maintainability;  Deep bed filters may be operated with either
manual or automatic backwash.  In either case, they must be
periodically inspected for media attrition, partial plugging,
and leakage.  Where backwashing is not used, collected solids
must be removed by shoveling, and filter media must be at least
partially replaced.

Solid Waste Aspects:  Filter backwash is generally recycled  with-
in the wastewater treatment system, so that the solids ultimately
appear in the clarifier sludge stream for subsequent dewatering.
Alternatively, the backwash stream may be dewatered directly or,
if there is no backwash, the collected solids may be suitably
disposed.  In either of these situations there is a solids dis-
posal problem similar to that of clarifiers.

Demonstration Status

Deep bed filters are in common use in municipal treatment plants.
Their use in polishing industrial clarifier effluent is increas-
ing, and the technology is proven and conventional.
                             VI1-61

-------
COMMON METALS WASTE TREATMENT SYSTEM PERFORMANCE  -  OPTION 2
Performance - Plants were selected that were visited  and  sampled
and were operating an Option 2 type treatment  system.   Plants  with
poorly operating treatment systems were then deleted  from the  data
set using the same exclusion criteria detailed  for  Option 1  plants.

Plots of raw waste vs. effluent were generated  for  the  following
parameters:  total suspended solids, cadmium,  total chromium,
copper, iron, lead, nickel, zinc, and fluorides.  These plots
are presented as Figures 7-37 through 7-45.  The mean effluent
concentrations for these parameters were calculated and are
presented in Table 7-8.

                         TABLE 7-8

           OPTION 2 MEAN EFFLUENT CONCENTRATIONS
           Parameter

      Total Suspended Solids
(118) Cadmium
(119) Chromium, Total
(120) Copper
      Iron
(122) Lead
(124) Nickel
(128) Zinc
      Fluorides
        12.7
        .011
        .319
        .368
        .257
        .034
        .550
        .247
        4.76
The variability factors presented in Table 7-5 were used in
conjunction with the mean effluent concentrations shown in
Table 7-8 to establish the daily maximum and 30-day average
concentrations listed in Table 7-9 for the Option 2 treatment
of common metals.  Table 7-10 provides a listing of Metal
Finishing Category plants in the data base which have an
Option 2 treatment system.

                            TABLE 7-9

          OPTION 2 COMMON METAL SUBCATEGORY CONCENTRATIONS
     Pollutant

      Total Suspended Solids
(118)  Cadmium
(119)  Chromium
(120)  Copper
   Concentration (mg/1)

Daily Max.      30-Day-Avg,
     36.8
     0.03
     1.24
     1 .18
16.5
.015
0.45
0.48
                              VII-62

-------
                     TABLE 7-9  (Con't)
      OPTION 2 COMMON METAL SUBCATEGORY CONCENTRATIONS

                                   Concentration  (mg/1)

     Pollutant                     Daily Max.        30-Day-Avg.

      Iron                            0.75             0.33
 (122) Lead                            0.10             0.04
 (124) Nickel                          1.60             0.72
 (128) Zinc                            0.74             0.32
      Fluorides                       13.8             6.19

 The data collection portfolios  (DCP's) received from non-visited
 facilities were also screened for plants which have  an Option 2
 common metals treatment system.  Of these plants, twenty  reported
 effluent concentration data.  Effluent concentration statistics
 were generated and the percentile distribution for these  effluent
 concentrations are presented in Figures 7-46 through 7-54.  Be-
 cause these plants were not visited,  it is not possible to know
 which plants were not operating properly and should  be deleted.

                         TABLE  7-10

   METAL FINISHING PLANTS WITH  OPTION 2 TREATMENT SYSTEMS
                     FOR COMMON METALS
     04140               19069               33070
     04151               27042               33073
     06062               28121               33110
     06131               30159               36048
     11096               30519               36082
     11182               30927               36102
     12075               31021               38223
     12077               31022               40047
     13031               31033               44150
     13033               31044               45041

The Option 2 daily maximum concentrations that were presented  in
Table 7-9 are overlayed onto these distribution plots for direct
comparison of the visited plant sampling data with these DCP data.

Figures 7-37 through 7-45 present effluent concentration as a
function of raw waste concentration for the entire metal finishing
Option 2 data base.  Data are presented for the eight pollutants
that were selected for limitation in the Common Metals Subcategory
and the daily maximum concentration for each pollutant is overlayed
for comparison.  Table 7-11 summarized the percentage of the metal
finishing data base that is in compliance with the daily maximum
concentration limitation for the sampled plants, the entire sampled
data base, and the DCP data base.
                           VII-63

-------
I
CTl
            o
            tH
               56-
               40-
            DI
            4J
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a
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               24
               16-
                                                                                                         O
                                                                         Daily Maximum Total Suspended Solids
                                                                                           0
                                                                                         O
                                                                                          o


                                                                                          0
                                                                                                  O
                                                                                                 e
                                                                                        o
                                                  10                               100

                                               Total  Suspended Solids Raw Waste (mg/1)
                                                                                                         1000
                                                               FIGURE 7-37


                                       EFFLUENT TSS CONCENTRATIONS  vs RAW WASTE CONCENTRATIONS
                                                                OPTION 2

-------
s
M

cn



rH
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01 . UZU
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                                                Cadmium Raw Waste (mg/1)
                                                      FIGURE  7-38



                              EFFLUENT CADMIUM CONCENTRATIONS vs RAW WASTE CONCENTRATIONS

                                                       OPTION 2

-------
CTl
01
             1.4
             1.2-
            1.0-
            0.8-
          C
          (U
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          i—i
          M-l
          M-l
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          3
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            0.4-
            0.2'
                         J
                                      O
                                                O
                                                                              Daily Maximum Chromium
                                                                                    O
                                                10                              100

                                                   Chromium  Raw Waste  (mg/1)
                                                                                                    1000
                                                           FIGURE 7-39


                                 EFFLUENT  CHROMIUM CONCENTRATIONS vs  RAW WASTE  CONCENTRATIONS
                                                             OPTION 2

-------
1.50-
1.25-
rH
I1 i.oo-
4J
c
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0.1
1.0                            10
    Copper  Raw Waste  (mg/1)
100
                                        FIGURE 7-40

                 EFFLUENT COPPER CONCENTRATIONS vs  RAW WASTE  CONCENTRATIONS
                                         OPTION 2

-------
           1.4

-------
Ol
<£>
              ,14
             ,12
             .10
           6 .08
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             .04
             .02
               0.
               0.1
                                                                        o
                                                                                 Daily Maximum Lead
                                  0.2             0.3         0.4      0.5     0.6   0.7   0.8  0.9  1.0

                                          Lead Raw Waste  (mg/1)
                                                          FIGURE 7-42


                                   EFFLUENT  LEAD CONCENTRATIONS VS  RAW WASTE CONCENTRATIONS
                                                           OPTION  2

-------
1 . / 3
1.50-
1.25-
rH
\
CT>
r i.oo-
c
Ol
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0.1
1.0
            10

Nickel Raw Waste (mg/1)
                                                                    100
1000
                                    FIGURE 7-43

             EFFLUENT NICKEL CONCENTRATIONS vs RAW WASTE CONCENTRATIONS
                                     OPTION 2

-------
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10 10
                Zinc  Raw  Waste .(mg/1)
                      FIGURE 7-44

EFFLUENT ZINC CONCENTRATIONS  vs  RAW WASTE CONCENTRATIONS
                        OPTION 2

-------
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to
94 -
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                                                              10

                                                Fluorides Raw Waste  (mg/1)
100
                                                       FIGURE 7-45


                              EFFLUENT FLUORIDES CONCENTRATIONS vs RAW WASTE  CONCENTRATIONS

                                                        OPTION 2

-------
   280-1
  240-
  200-
  160-
4J
c
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3
10
•o
w 120'
T3

-------
   0.7
   0.6
  0.5 -
en
E
  0.4-
4J

C
I °-3'
10

U
  0.2-
  0.1-
                   Daily Maximum
                                           o
                10
                           20
30        40         50         60

          Percentile Distribution
                                                                               70
                                                                                         80
                                                                                                    90
                                            FIGURE 7- 47



                            DCP DATA  FOR CADMIUM EFFLUENT DISTRIBUTION



                                             OPTION 2

-------
    5.6
    4.8-
 en
4J
c
HI
3
   3.2-
O
43
O
   2.4-
-U
O
EH
   1.6-
                                       Daily Maximum
   0.8-
                                                                                          G)
           i i Bi
                                       -ffl-
                 10
20
           30
 40         50        60
Percentile  Distribution
                                                                                70
                                                               80
90
                                                  FIGURE 7- 48

                                 DCP DATA FOR  CHROMIUM EFFLUENT  DISTRIBUTION
                                                    OPTION 2

-------
  2.8-\
   2.4-
   2.0-
  1.6-
C
QJ
w 1.2


(D
o
u
  0.8-
                 Daily Maximum
   0.4-
                       a  a
                            a
             00°
                                   a a
                                             a
                20
      40        60

Percentile Distribution
                                               80
100
                         FIGURE 7-49



          DCP DATA FOR COPPER EFFLUENT  DISTRIBUTION

                           OPTION  2
                               VI1-76

-------
s
M
                  2.8 -I
                  2.4-
                  2.0-
               cn
               —  1.6
               c
               3
                 1.2-
                 0.8-
                 0.4-
 Daily Maximum
                                             Q
                                                                     ID
                               10
20
30
 40        50         60
Percentile Distribution
                                                                                             D
                                                                                             70
                                                              80
                                                                                                                  90
                                                                 FIGURE 7-50

                                                  DCP  DATA  FOR IRON EFFLUENT DISTRIBUTION
                                                                   OPTION 2

-------
                  .175-
                  .150-
                 .125-
                                                                                                         CJ
en
e
               4J
               c
               (1)
               D
                  100-
                                         Daily Maximum
i
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CX)
                 .075-
               1C
               0)
                 .050-
                 .025-
                                10
                                           20
                                                     30
                                                 40         50         60

                                                 Percentile  Distribution
                                                                                                70
80
90
                                                              FIGURE  7-51



                                               DCP  DATA FOR LEAD EFFLUENT  DISTRIBUTION

                                                                OPTION  2

-------
                  1.4
                  1.2-
                  1.0-
                                                                                                               GJ
                en
                  0.8-
                c
                0)
                3
s
l-l
                w
                  0.6-
                  0.4-
                  0.2-
                                                                                   a
                                I p.. ,.fl
                               10
   Q    o     n

20        30
 40        50        60

Percentile Distribution
70
                                                                                                      80
                                                                       90
                                                                                                  Daily  Maximum =  1.6
                                                                FIGURE 7- 52


                                                 DCP DATA FOR NICKEL EFFLUENT DISTRIBUTION

                                                                  OPTION 2

-------
   6-                                                    a
   5
cr

5  4

4J
c

-------
   28
   24-
   20-
4J
c  16'
01
3
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to
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•D  12
o
6-,
    8-
    4-
      D
                    Daily Maximum
                                       m
     24
32
                          40
48        56         64

   Percentile Distribution
                                                                   72
                                                               80
                                                                         88
                                                                                   96
                                            FIGURE  7-54


                            DCP DATA FOR FLUORIDES  EFFLUENT DISTRIBUTION
                                              OPTION 2

-------
                           TABLE 7-11
          PERCENTAGE OF MFC DATA BASE BELOW THE  DAILY
          MAXIMUM CONCENTRATION LIMITATION  FOR OPTION 2 (%)
Pollutant
Cadmium
Chromium, Total
Copper
Iron
Lead
Nickel
Zinc
Fluorides
Sampled Plants
After Deletions

     100.0
     100.0
     85.7
     93.3
     100.0
     91.7
     88.2
     88.9
  All Sampled
    Plants

  100.0
  100.0
  88.2
  87.5
  100.0
  92.8
  88.2
  88.9
         DCP  Data Base

          46.1
          88.8
          90.0
          75.0
          62.5
          100.0
          63.6
          66.7
Summary tables are provided to show a direct comparison  of  the
mean, daily maximum, and 30-day average concentrations for  Options 1
and 2.  Table 7-12 presents a comparison on the mean  concentrations
and Table 7-13 lists the daily maximum and 30-day average concen-
trations for each.

                           TABLE 7-12
       OPTION 1 AND OPTION 2 MEAN CONCENTRATION COMPARISON
                                       Concentration  (mg/1)
    Pollutant

      Total Suspended
(118) Cadmium
(119) Chromium
(120) Copper
      Iron
(122) Lead
(124) Nickel
(128) Zinc
      Fluorides
  Solids
Option 1

  17.8
  .012
  .572
  .814
  .797
  .050
  .942
  .551
  15.3
 Option 2

   12.7
   .011
   .319
   .368
   .257
   .034
   .550
   .247
   4.76
                           TABLE 7-13
          OPTION 1 AND OPTION 2 LIMITATION COMPARISON
Parameter

      Total Suspended
        Solids
(118)  Cadmium
(119)  Chromium
                     Concentration (mg/1)

             Option 1                Option 2

     Daily Max.  30-Day-Ave.  Daily Max. 30-Day-Ave.
        51.6
        0.04
        2.23
  23.1
  0.02
  0.80
36.8
0.03
1.24
16.5
.015
0.45
                            VI1-82

-------
                      TABLE 7-13 (Con't)
          OPTION 1 AND OPTION 2 LIMITATION COMPARISON

                                         Concentration  (mg/1)

                                 Option 1                 Option  2

Parameter                Daily Max. 30-Day-Ave.  Daily  Max.  30-Day-Ave

(120) Copper                2.61        1.06        1.18         0.48
      Iron                  2.31        1.04        0.75         0.33
(122) Lead                  0.15        0.07        0.10         0.04
(124) Nickel                2.73        1.23        1.60         0.72
(128) Zinc                  1.65        0.72        0.74         0.32
      Fluorides             44.4        19.9        13.8         6.19

TREATMENT OF COMMON METALS WASTES - OPTION 3^

The Option 3 treatment system for metal wastes consists of the
Option 2 end-of-pipe treatment system plus the addition of in-
plant controls for lead and cadmium.  In-plant controls could
include evaporative recovery, ion exchange, and recovery  rinses.
The purpose of these in-plant controls is to eliminate  cadmium
and lead from the raw waste stream entirely.  These additional
controls will minimize the chance of discharging either of these
highly toxic metals due to treatment system failure.

Performance - The performance of the Option 3 treatment system
will be identical to the Option 2 treatment system with the  excep-
tion that only background concentration levels of lead  and cadmium
(<0.01 mg/1) are allowable for discharge.

Common Metals Treatment Techniques

The following paragraphs describe common metals treatment tech-
niques that are applicable to Option 3:  evaporation and  ion
exchange -

EVAPORATION

Evaporation is a concentration process.  Water is evaporated from
a solution, increasing the concentration of solute in the remaining
solution.  If the resulting water vapor is condensed back to a
liquid, the evaporation-condensation process is called  distillation.
However, to be consistent with industry terminology, evaporation is
used in this report to describe both processes.  Both atmospheric
and vacuum evaporation are commonly used in industry today.  Spe-
cific evaporation techniques are shown in Figure 7-55 and discussed
below.
                              VI1-83

-------
   PACKED TOHtlH
    EVAPORATOR
                           WATER VAPOR
                                              .EXHAUST
                                                             HEAT
                                                          EXCHANGER
                                                    CONDENSATE
                                                    rnnrpNTRATE
                     ATMOSPHERIC EVAPORATOR
                                                                                 EVAPORATOR-
                                                                                      STEAM
                                                                                    STEAM
                                                                                  CONDENSATE"
                                                                                 WASTEWATER-
                                                                                                                                    CONDENSER
                                                                                                         ""SKSSS"   ^PARATOR
                                                                                                    \     MIXTURE     -K«-™
                                                                                                                           WATER VAPOR
                                                                                                           LIQUID  RETURN
1
                                                                                                                                                    COOLING
                                                                                                                              I—«-lt
                                                                                                                                           .CONDENSATE
                                                                                                                              VACUUM PUMP
                                                                                                                                           -.CONCENTRATE
                                                                                                         CLIMBING FILM EVAPORATOR
M

<&>
CONDENSATE-*
WASTEWATER
  CONCENTRATE—
                                                COOLING

                                                 WATER
                                                      VACOUM
                                                 STEAM
                                                    STEAM
                                                  CONUEHSATE
                                                                  STEAM
                                                                  WASTE
                                                                  WATER
                                                                   FEKD
                                                                                      HOT VAPOR
                                                                                          STEAM
                                                                                       CONDENSATE
                                                                                                                        VAPOR
                                                                                          CONCENTRATE
                                                                                                                          CONDENSER
                                                                                                            -^*,
                                                                                                                                     /
                                                                                                                                    /
                                                                                                                            CONDENSATE

                                                                                                                                          »
                                                                                                                                         WATER
                                                                                                                                         VACUUM  PUMP
                                                                                                                                            0-
                                                                                                                                                    EXIIAU:
                                                                                                                                        ACCUMULATOR
        FOR
       REUSE
                                                                                                                              CONCENTRATE FOR REUSE
                                                                                                                              •            m
                    SUBMCKGLD TUtE EVAPORATOR
                                  /f C
                                                                                                     tlfUIBI.E-F-FFECT EVAPORATOR
                                                                FIGURE  7-55

                                                    TYPES  OF EVAPORATION  EQUIPMENT

-------
Atmospheric evaporation could be accomplished simply by boiling  the
liquid.  However, to aid evaporation, heated liquid is sprayed on
an evaporation surface, and air is blown over the surface and sub-
sequently released to the atmosphere.  Thus, evaporation occurs  by
humidification of the air stream, similar to a drying process.
Equipment for carrying out atmospheric evaporation is quite simi-
lar for most applications.  The major element is generally a packed
column with an accumulator bottom.  Accumulated wastewater is
pumped from the base of the columm, through a heat exchanger, and
back into the top of the column, where it is sprayed into the pac-
king.  At the same time, air drawn upward through the packing by
a fan is heated as it contacts the hot liquid.  The liquid par-
tially vaporizes and humidifies the air stream.  The fan then
blows the hot, humid air to the outside atmosphere.  A scrubber
is often unnecessary because the packed column itself acts as a
scrubber.

Another form of atmospheric evaporation combines evaporative re-
covery of plating chemicals with plating tank fume control.  A
third form of atmospheric evaporation also works on the air humidi-
fication principle, but the evaporated rinse water is recovered
for reuse by condensation.  These air humidification techniques
operate well below the boiling point of water and can utilize
waste process heat to supply the energy required.

In vacuum evaporation, the evaporation pressure is lowered to
cause the liquid to boil at reduced temperature.  All of the water
vapor is condensed and, to maintain the vacuum condition, noncon-
densible gases (air in particular) are removed by a vacuum pump.
Vacuum evaporation may be either single or double effect.  In
double effect evaporation, two evaporators are used, and the
water vapor from the first evaporator (which may be heated by
steam) is used to supply heat to the second evaporator.  As
it supplies heat, the water vapor from the first evaporator
condenses.  Approximately equal quantities of wastewater are
evaporated in each unit; thus, the double effect system evapor-
ates twice the amount of water that a single effect system does,
at nearly the same cost in energy but with added capital cost
and complexity.  The double effect technique is thermodynamically
possible because the second evaporator is maintained at lower
pressure (higher vacuum) and, therefore, lower evaporation temper-
ature.  Another means of increasing energy efficiency is vapor
recompression (thermal or mechanical), which enables heat to be
transferred from the condensing water vapor to the evaporating
wastewater.  Vacuum evaporation equipment may be classified as
submerged tube or climbing film evaporation units.
                               VI1-85

-------
In the most commonly used submerged tube evaporator,  the  heating
and condensing coil are contained in a single vessel  to reduce
capital cost.  The vacuum in the vessel is maintained by  an  eductor-
type pump, which creates the required vacuum by  the flow  of  the
condenser cooling water through a venturi.  Wastewater accumulates
in the bottom of the vessel, and it is evaporated by  means of sub-
merged steam coils.  The resulting water vapor condenses  as  it
contacts the condensing coils in the top of the  vessel.   The
condensate then drips off the condensing coils into a collection
trough that carries it out of the vessel.  Concentrate is removed
from the bottom of the vessel.  The major elements of the climbing
film evaporator are the evaporator, separator, condenser, and
vacuum pump.  Wastewater is "drawn" into the system by the vacuum
so that a constant liquid level is maintained in the  separator.
Liquid enters the steam-jacketed evaporator tubes, and part  of it
evaporates so that a mixture of vapor and liquid enters the  separ-
ator.  The design of the separator is such that  the liquid is con-
tinuously circulated from the separator to the evaporator.   The
vapor entering the separator flows out through a mesh entrainment
separator to the condenser, where it is condensed as  it flows down
through the condenser tubes.  The condensate, along with  any en-
trained air, is pumped out of the bottom of the  condenser by a
liquid ring vacuum pump.  The liquid seal provided by the condensate
keeps the vacuum in the system from being broken.

Application and Performance

Evaporation is used in the Metal Finishing Category for recovery
of a variety of metals, bath concentrates, and rinse  waters.

Both atmospheric and vacuum evaporation are used in metal finishing
plants, mainly for the concentration and recovery of  plating
solutions.  Many of these evaporators also recover water  for
rinsing.  Evaporation has also been applied to recovery of
phosphate metal cleaning solutions.  There is no fundamental limit-
ation on the applicability of evaporation.  Recent changes in con-
struction materials used for climbing film evaporators enable them
to process a wide variety of wastewaters (including cyanide-bearing
solutions), as do the other types of evaporators described in this
report.


In theory, evaporation should yield a concentrate and a deionized
condensate.  Actually, carry-over has resulted in condensate metal
concentrations as high as 10 mg/1, although the usual  level  is less
than 3 mg/1, pure enough for most final rinses.  The  condensate  may
also contain organic brighteners and antifoaming agents.  These  can
be removed with an activated carbon bed, if necessary.  Samples
                             VII-86

-------
from one metal finishing plant showed 1,900 mg/1 zinc in the  feed,
4,570 mg/1 in the concentrate, and 0.4 mg/1 in the condensate.
Another plant had 416 mg/1 copper in the feed and 21,800 mg/1  in
the concentrate.  Chromium analysis for that plant indicated  5,060
mg/1 in the feed and 27,500 mg/1 in the concentrate.  Evaporators
are available in a range of capacities, typically from 15 to  75 gph,
and may be used in parallel arrangements for processing of higher
flow rates.

Advantages and Limitations

Advantages of the evaporation process are that it permits recovery
of a wide variety of process chemicals, and it is often applicable
to removal and/or concentration of compounds which cannot be  ac-
complished by any other means.  The major disadvantage is that
the evaporation process consumes relatively large amounts of  energy
for the evaporation of water.  However, the recovery of waste  heat
from many industrial processes (e.g., diesel generators, incinera-
tors, boilers and furnaces) should be considered as a source  of
this heat for a totally integrated evaporation system.  For some
applications, pretreatment may be required to remove solids and/or
bacteria which tend to cause fouling in the condenser or evaporator.
The buildup of scale on the evaporator surfaces reduces the heat
transfer efficiency and may present a maintenance problem or  in-
creased operating cost. However, it has been demonstrated that
fouling of the heat transfer surfaces can be avoided or minimized
for certain dissolved solids by maintaining a seed slurry which
provides preferential sites for precipitate deposition.  In addi-
tion, low temperature differences in the evaporator will eliminate
nucleate boiling and supersaturation effects.  Steam distillable
impurities in the process stream are carried over with the product
water and must be handled by pre or post treatment.

Operational Factors

Reliability;  Proper maintenance will insure a high degree of  reli-
ability for the system.  Without such attention, rapid fouling or
deterioration of vacuum seals may occur, especially when handling
corrosive liquids.

Maintainability;  Operating parameters can be automatically con-
trolled.Pretreatment may be required, as well as periodic
cleaning of the system.  Regular replacement of seals, especially
in a corrosive environment, may be necessary.

Solid Waste Aspects;  With only a few exceptions, the process  does
not generate appreciable quantities of solid waste.
                             VII-87

-------
Demonstration Status

Evaporation is a fully developed, commercially  available  wastewater
treatment system.  It is used extensively to recover  plating chem-
icals, and a pilot scale unit has been used in  connection with
phosphate washing of aluminum coil.  Proven performance  in silver
recovery indicates that evaporation could be a  useful treatment
operation for the photographic industry, as well as for metal
finishing.

Evaporation has been used in 41 plants in the present data base
and these are identified in Table 7-14.

ION EXCHANGE

Ion exchange is a process in which ions, held by electrostatic
forces to charged functional groups on the surface of the ion ex-
change resin, are exchanged for ions of similar charge from the
solution in which the resin is immersed.  This  is classified as a
sorption process because the exchange occurs on the surface of
the resin, and the exchanging ion must undergo  a phase transfer
from solution phase to solid phase.  Thus, ionic contaminants in
a waste stream can be exchanged for the harmless ions of  the resin.

Although the precise technique may vary slightly according to the
application involved, a generalized process description follows.
The wastewater stream being treated passes through a  filter to
remove any solids, then flows through a cation  exchanger  which con-
tains the ion exchange resin.  Here, metallic impurities  such as
copper, iron, and trivalent chromium are retained.  The stream then
passes through the anion exchanger and its associated resin. Hexa-
valent chromium, for example, is retained in this stage.   If one
pass does not reduce the contaminant levels sufficiently,  the
stream may then enter another series of exchangers.   Many ion ex-
change systems are equipped with more than one  set of exchangers
for this reason.

The other major portion of the ion exchange process concerns the
regeneration of the resin, which now holds those impurities re-
tained from the waste stream.  An ion exchange  unit with  in-place
regeneration is shown in Figure 7-56.  Metal ions such as  nickel
are removed by an acidic cation exchange resin, which is  regener-
ated with hydrochloric or sulfuric acid, replacing the metal ion
with one or more hydrogen ions.  Anions such as dichromate are
removed by a basic anion exchange resin, which  is regenerated with
sodium hydroxide, replacing the anion with one  or more hydroxyl
ions.  The three principal methods employed by  industry for regen-
erating the spent resin are:
                               VI1-88

-------
WASTE WATER CONTAINING
   DISSOLVED METALS
    OR OTHER IONS
                                            DIVERTER VALVE
    REGENERANT TO REUSE,

  TREATMENT, OR DISPOSAL
       REGENERANT
        SOLUTION
                                         DIVERTER VALVE
 METAL-FREE WATER

FOR REUSE OR DISCHARGE
                            FIGURE 7-56
                ION EXCHANGE WITH REGENERATION
                                  VI1-89

-------
Application and Performance

Many metal finishing facilities utilize  ion  exchange to concentrate
and purify their plating baths.

The list of pollutants for which the  ion exchange  system has proven
effective includes aluminum, arsenic, cadmium,  chromium (hexavalent
and trivalent), copper, cyanide, gold, iron,  lead,  manganese, nickel,
selenium, silver, tin, zinc, and more.  Thus,  it can be applied to
a wide variety of industrial concerns.  Because of  the  heavy con-
centrations of metals in their wastewater, the metal finishing
industries utilize ion exchange in several ways.  As an end-of-pipe
treatment, ion exchange is certainly  feasible, but  its  greatest
value is in recovery applications.  It is commonly  used,  however,
as an integrated treatment to recover rinse  water and process chem-
icals.  In addition to metal finishing, ion  exchange is finding
applications in the photography industry for  bath purification, in
battery manufacturing for heavy metal removal,  in the chemical in-
dustry, the food industry, the nuclear industry, the pharmaceutical
industry, the textile industry, and others.   It could also  be used
in the copper and copper alloys industry for  recovery of  copper
from pickle rinses.  Also, many industrial and non-industrial con-
cerns utilize ion exchange for reducing the  salt concentrations in
their incoming water.

Ion exchange is highly efficient at recovering metal finishing
chemicals.  Recovery of chromium, nickel, phosphate  solution,  and
sulfuric acid from anodizing is in commercial use.   A chromic acid
recovery efficiency of 99.5% has been demonstrated.   Typical  data
for purification of rinse water in electroplating and printed cir-
cuit board plants are shown in Table  7-15.

Plant ID 11065 which was visited and  sampled, employs an  ion
exchange unit to remove metals from rinsewater.  The results  of
the sampling are displayed in Table 7-16.

Advantages and Limitations

Ion exchange is a versatile technology applicable to a  great  many
situations.  This flexibility, along with its compact nature  and
performance, make ion exchange a very effective method  of waste
water treatment.  However, the resins in these systems  can  prove
to be a limiting factor.  The thermal limits of the  anion resins,
generally placed in the vicinity of 60° C, could prevent  its  use
in certain situations.  Similarly, a  nitric  acid, chromic acid,
and hydrogen peroxide can all damage  the resins as will  iron,
manganese, and copper when present with sufficient concentrations
of dissolved oxygen.   Removal of a particular trace  contaminant
may be uneconomical because of the presence of other ionic  species
that are preferentially removed.  The regeneration of the resins
presents its own problems.  The cost of the regenerative  chemicals
can be high.   In addition, the waste  streams originating  from the
                               VI1-90

-------
A)    Replacement Service;   A replacement service replaces the spent
     resin with regenerated resin, and regenerates the spent resin
     at its own facility.   The service then has the problem of
     treating and disposing of the spent regenerant.

B)    In-Place Regeneration;  Some establishments may find it less
     expensive to do their own regeneration.  The spent resin col-
     umn is shut down for  perhaps an hour, and the spent resin is
     regenerated.  This results in one or more waste streams which
     must be treated in an appropriate manner.  Regeneration is
     only performed as the resins require it.

C)    Cyclic Regeneration;   In this process, the regeneration of
     the spent resins takes place in alternating cycles with the
     ion removal process.   A regeneration frequency of twice an
     hour is typical.  This very short cycle time permits opera-
     tion with a very small quantity of resin and with fairly con-
     centrated solutions,  resulting in a very compact system. Again,
     this process varies according to application, but the regener-
     ation cycle generally begins with caustic being pumped through
     the anion exchanger,  carrying out hexavalent chromium, for ex-
     ample, as sodium dichromate.  The sodium dichromate stream
     then passes through a cation exchanger, converting the sodium
     dichromate to chromic acid.  After concentration by evaporation
     or other means, the chromic acid can be returned to the process
     line.  Meanwhile, the cation exchanger is regenerated with
     sulfuric acid, resulting in a waste acid stream containing
     the metallic impurities removed earlier.  Flushing the exchang-
     ers with water completes the cycle.  Thus, the wastewater is
     purified and, in this example, chromic acid is recovered.  The
     ion exchangers, with  newly regenerated resin, then enter the
     ion removal cycle again.

                        Table 7-14
        Metal Finishing Plants Employing Evaporation

                    04266           20147
                    04276           20160
                    04284           20162
                    06009           23071
                    06037           28075
                    06050           30096
                    06072           33033
                    06075           33065
                    06087           33112
                    06088           34050
                    06090           36062
                    06679           36084
                    08060           36162
                    12065           38050
                    12075           38052
                    13031           40062
                    19069           40836
                    20064           43003
                    20069           61001
                    20073


                           VI1-91

-------
                          Table  7-15
            Typical  Ion  Exchange Performance Data
Parameter
All Values mg/1

Zinc  (Zn)
Cadmium  (Cd)  _
Chromium  (Cr+g)
Chromium  (Cr   )
Copper (Cu)
Iron  (Fe)
Nickel (Ni)
Silver (Ag)
Tin (Sn)
Cyanide  (CN)
Manganese  (Mn)
Aluminum  (Al)
Sulfate  (S04)
Lead  (Pb)
Gold  (Au)
    Electroplating  Plant
    Prior ToAfter
    Purifi-       Purifi-
    cation        cation
             Printed  Circuit Board Plant
    14.8
    5.7
    3.1
    7.1
    4.5
    7.4
    6.2
    1.5
    1.7
    9.8
    4.4
    5.6
  0.40
  0.00
  0.01
  0.01
  0.09
  0.01
  0.00
  0.00
  0.00
  0.04
  0.00
  0.20
             Prior  To
             Purifi-
             cation
43.0

1.60
9.10
1.10
3.40
                               210.00
                               1.70
                               2.30
              After
              Purifi-
              cation
0.10

0.01
0.01
0.10
0.09
                               2.00
                               0.01
                               0.10
                         Table  7-16
            Sampling Results  From  Plant  ID 11065
Parameter

TSS
Cu
Ni
Cr, Total
Cd
Sn
Pb
          Day 1
  Input To
Ion Exchange

   6.0
   52.080
   .095
   .043
   .005
   .06
   .010
Effluent From
Ion Exchange

   4.0
   .118
   .003
   .051
   .005
   .06
   .011
         Day 2
    Input To
   Ion Exchange

        1.0
        189.3
        .017
        .026
        .005
        .06
        .010
   Output From
   Ion Exchange

      1.0
      .20
      .003
      .006
      .005
      .06
      .010
                               VII-92

-------
regeneration process are extremely high in pollutant concentra-
tions, although low in volume.  These must be further processed
for proper disposal.

Operational Factors

Reliability:  With the exception of occasional clogging or fouling
of the resins, ion exchange has been shown to be a highly depen-
dable technology assuming proper prior treatment of the waste
stream has taken place.

Maintainability;  Along with the normal maintenance of pumps,
valves, and other hardware, the regeneration process constitutes
the largest portion of the maintenance requirements.  Unless the
cyclic type regeneration is used, the regeneration process inevi-
tably involves the shutdown of the ion exchange units as well as
additional labor costs.  In most cases, however, the regeneration
process can be effected quickly and easily.

Solid Waste Aspects;  Few, if any, solids accumulate within the
ion exchangers, and those which do appear are removed by the re-
generation process.  Proper prior treatment and planning can eli-
minate solid buildup problems altogether.  In fact, use of ion
exchange for recovery avoids sludge generation that would result
from end-of-pipe treatment.

Demonstration Status

All of the applications mentioned in this document are available
for commercial use.  The research and development in ion exchange
is focusing on improving the quality and efficiency of the resins,
rather than new applications.  Work is also being done on a contin-
uous regeneration process whereby the resins are contained on a
fluid-transfusible belt.  The belt passes through a compartmented
tank with ion exchange, washing, and regeneration sections.  The
resins are therefore continually used and regenerated.  No such
system, however, has been reported to be beyond the pilot stage.

Ion exchange is used in 63 plants in the present data base and
these are identified in Table 7-17.
                               VI1-93

-------
                  Table 7-17
Metal Finishing Plants Employing Ion Exchange
        02033
        02034
        02037
        04145
        04221
        04223
        04236
        04263
        04541
        04676
        04690
        05050
        06103
        06679
        08073
        09025
        11065
        12065
        12075
        12080
        13040
17030
17050
17061
18538
19081
19120
20017
20075
20120
20162
20483
21059
21065
21066
21075
23065
25033
27046
28111
28121
30153
30967
31032
31050
31070
33130
33172
33186
33187
36087
36623
37060
38036
38039
40048
40061
41086
41089
44062
46035
61001
62032
                      VI1-94

-------
ALTERNATIVE TREATMENT METHODS FOR COMMON METALS  REMOVAL

In addition to the treatment methods described under  Options  1,  2,
and 3; there are several other alternative treatment  technologies
applicable for the treatment of common metals wastes.   These  tech-
nologies may be used in conjunction with or  in place  of the Option
lt 2, or 3 system components.  The following paragraphs describe
these technologies:  electrolytic recovery, electrodialysis,  re-
verse osmosis, peat adsorption, insoluble starch  xanthate, sul-
fide precipitation, flotation, and membrane filtration.

ELECTROLYTIC RECOVERY

Electrolytic recovery is a process in which there  is  electrochemical
reduction of metal ions at the cathode where these  ions are reduced
to elemental metal.  At the same time, there is evolution of  oxygen
at the anode.  Electrolytic recovery is used primarily  to remove
metal ions from solutions.

Conventional Electrolytic Recovery

Conventional Electrolytic Recovery Equipment - Equipment consists
of a drag-out recovery tank located in the production line and an
electrolytic recovery tank and recirculation pump,  remote from the
line.  A typical electrolytic recovery tank uses  stainless steel
cathodes of approximately 15 cm. width upon which  the recovered
metal is deposited.  After the coating is sufficiently  thick  (0.06
cm.), the metal deposited can be peeled off and returned to the
refiner or the metal plated stainless steel can be  used for anodes
in a plating bath.

To get high recovery efficiencies, it is desirable  that the solu-
tion be reasonably well agitated in the electrolytic  cell where the
cathode sheets are in use.  The electrolytic recovery tank is
designed to produce high flow rates in a narrow channel.


To avoid buildup of harmful impurities in the recirculated solution,
approximately 20 percent of the solution should be  dumped to  waste
treatment each week.

Application of_ Conventional Electrolytic Recovery  - Electrolytic
recovery is used to recover copper,tin, silver,  and  other metals
from plating and etching bath dragout.  Because the electrolytic
process maintains a low concentration of metal in  the drag-out
recovery process relative to that in the process  bath,  metal  drag-
over into the succeeding rinse tank is minimized.   This, in turn,
minimizes the load on the waste treatment system  and  the eventual
pollutant discharge rate.
                                VII-95

-------
Performance of Conventional Electrolytic Recovery- Performance  is
best illustrated by the actual examples tabulated below:

Parameter                          Tin Plating    Silver  Plating

Plating Bath Concentration, g/1        81               82
Drag-out Tank Concentration, g/1       1.2              0.2
Drag-out Rate, gph                     1.2              0.8
Recovery Efficiency, %                 97-99            99.8
Cathode Area, sq. ft.                  45               35
Current Density, amp/sq„ ft.           5-10             3-5
Current Efficiency, %                  70            25-50
Current, amp                           240              175

Advanced Electrolytic Recovery

Advanced Electrolytic Recovery Equipment - The extended surface
electrolysis recovery system (ESE)discussed here recovers metal
better at low concentrations than at high concentrations, whereas
the conventional electrolytic recovery system is only good for
recovery of metal at high concentrations.  An extended surface
electrolytic recovery unit removes contaminant metals by elec-
troplating them onto a specially constructed flow-through
electrode.

The electrolytic processing technique involves reduction of the
metal ions at the cathode to form the elemental metal, with
evolution of oxygen at the anode.  Other cathodic reactions, such
as the reduction of ions to produce hydrogen gas, may also occur
depending on the chemical composition of the streams being treated.

The ESE spiral cell is of sandwich construction containing a fixed
"fluffy" cathode, a porous insulating separator, an  anode of
screenlike material and another insulating separator.  The anode
and cathode material may vary with the particular effluent stream
to be treated.  Typically, cathode material is a fibrous woven
stainless steel mesh with a filament size of 2-5 mils.  This sand-
wich structure cathode, separator material, and anode are rolled
into a spiral and inserted into a pipe.  This type of cell construc-
tion results in a very open structure with a void volume of 93 per-
cent to 95 percent, which provides a low resistance  to fluid flow.

A number of cells can be stacked as modules so that  a large frac-
tion of contaminant metals can be recovered from an  effluent.  The
solution to be treated is pumped in at the top of the module and
flows down through the cells where the metals are plated out on the
cathode.  Figure 7-57 shows that as a copper-containing solution
                             VII-96

-------
flows through the cell stack, copper ions are attached  to  the
cathode and deposited as copper metal, hydroxyl  ions  are attracted
to the anode, and hydrogen and oxygen gas are given off.   The  fol-
lowing reactions take place at the cathode:
          Cu
            +2
                 2e- = Cu
and at  the  anode:

          2(OH-)  =
                         1/2
These reactions take place continuously as the fluid  is pumped
through the various cells in the cell stack.

Application of_ Advanced Electrolytic Recovery - Extended surface
electrolysis cells may be used commercially to plate  out copper,
lead, mercury, silver and gold.  This system should provide a
very efficient means of removal because of its low mass transfer
requirements, larger electrode surface area and, because of the
construction of the electrodes, increased electrical  efficiency-
This unit can be used in conjunction with conventional electro-
dialysis or other forms of treatment.

Performance of Advanced Electrolytic Recovery - Pollutants re-
covered by the ESE modules are independent of concentration levels.
Under mass-transfer-limiting conditions, this device  will operate
as efficiently at one mg/1 as at 1000 mg/1.  The effluent concen-
tration decreases exponentially with the length of the module and
its available cathode area.  Complexing of metals in  solution is a
problem in some applications.

The following table shows the level of achievable copper concen-
trations for three influent levels.  The final concentrations for
all three cases are less than 1 mg/1.

                Solution Concentration, mg/1
             At Various Points in a_ Cell Stack

Untreated  After 1 Cell  After 2 Cells  After 3 Cells  After 4 Cells
20.0
45.5
15.5
               8.2
               15.5
               5.6
3.4
5.4
2.8
1.3
2.1
1.7
0.6
0.9
0.7
With the addition of one more cell in all three cases,  the  cell
effluent level would be below 0.05 mg/1.

Plow to the ESE unit must be interrupted once a day for approxi-
mately one hour so that the accumulated metals in the cell  can be
stripped out by circulating an acidic cleaner through the cell.  A
schematic diagram, Figure 7-58, shows how the cell is placed  in a
plating line.  The graph in Figure 7-59 compares the effect of
electrical efficiency in metals reduction for ESE and planar
electrodes.
                              VII-97

-------
V£>
00
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DEPOSITED ,H2 / °2 ,H2 O2 ^^
COPPER / / / / / ^>^^












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       POROUS  INSULATING SEPARATOR
                                         FIGURE  7-57
                             EXTENDED SURFACE ELECTOLYSIS  CELLS

-------
DEIONIZED  WATER
FOR REUSE
1
1
n«. ••» M
1 "
* 1
§
|
ESE i
--J
UNIT ....j _
I
S
J§ WASTE WATER A ! 1
i '
1 '
,. — r '' 1
"l^___^j '^^^_^T* i i
— 	 ^ ! L '
-
WASTEV7ATER
HOLDING TANK t

1
1
1
INTERMITTENT CLEANING SYSTEM
•' 	 — — •
1
D.C.. 1
L POWER |
r SUPPLY 	 ' |
i 1
J METAL

*• i
j — L **i i

_j T j_ 1 '
L -i r- j
LEACHATE
TANK
RECOVERY UNIT i
1
                                       FIGURE 7-58


                        APPLICATION OF EXTENDED SURFACE ELECTROLYSIS

-------
                                 CATHODE:   Cu++ + 2e-
                                               -Cu'O
o
o
          100
          EH
          a
          w
         £
u
a
w
M
U
H
60
40
         w
U
H


EH
U
W
           20
            0

            10
          TYPICAL

         ALLOWABLE

         EFFLUENTS
     -I
            10
              0
                                                    CONVENTIONAL

                                                        (PLANAR)
                                                            v
                                                              v
10'
10
  2
10
  3
1CT
                                 COPPER CONCENTRATION, mg/1
                                                                      TYPICAL

                                                                      PLATING

                                                                      BATH
                                                                 10
5
                                             FIGURE 7-59


                                   EFFECT OF CONCENTRATION ON ELECTRICAL

                                   EFFICIENCY IN METALS REDUCTION.

-------
As indicated by the preceding table, a cell stack is at least 90
percent efficient in removal of metals from solution.  A 200 1/min
waste stream containing 50 mg/1 copper requiring a 100:1 concentra-
tion reduction could be treated in a 20 cm diameter ESE unit having
48 inches of active electrode length.  The electrical energy needed
to treat this stream in an ESE cell would approximate the energy
expended to drive the rake on a clarifier.

Demonstration Status

Electrolytic recovery is currently being used at 11 plants in
the present data base and these are identified in Table 7-18.

                         Table 7-18
   Metal Finishing Plants Employing Electrolytic Recovery

                    01068          19069
                    02033          20162
                    04069          28122
                    04071          31070
                    04690          36623
                    19063

ELECTRODIALYSIS

Electrodialysis is a process in which dissolved colloidal species
are exchanged between two liquids through selective semipermeable
membranes.  An electromotive force causes separation of the species
according to their charge, and the semipermeable membranes allow
passage of certain charged species while rejecting passage of op-
positely charged species.  Electrodialysis is used primarily to
remove and concentrate dilute solutions of salt and other chemi-
cals from a waste stream, thereby providing purified water.

Conventional electrodialysis systems consist of an anode and a
cathode separated by an anion permeable membrane near the anode
and a cation permeable membrane near the cathode.  This combinat-
ion forms an anode chamber, a cathode chamber, and center chamber.
Upon application of an electric charge, cations pass from the center
chamber to the cathode chamber.  This decreases the concentration of
salt in the center chamber.

Figure 7-60 shows the application of a simple electrodialysis
cell to separate potassium sulfate solution (KjSO.) into its
components.  Practical electrodialysis installations contain from
ten to hundreds of compartments between one pair of electrodes.
The application of an electric charge draws the cations to the
cathode and anions to the anode.  Industrial wastewater containing
metallic salts enters the center cell, and the charge takes the
                               VII-101

-------
(CATHODE)  __
 CATION-     ANION-
PERMEABLE  PERMEABLE
 MEMBRANE  MEMBRANE
     I
     I
             H2
                  OH-
        K2S04
I.
(ANODE)
                      FIGURE 7-60
                SIMPLE ELECTRODIALYSIS CELL
                       VII-102

-------
positive ions to the cathode and negative ions to the anode.  The
result is a significant reduction in salt concentration  in  the
center cell with an increase in solution concentrations  in  the
adjacent cells.  Thus, the water from the center of each of three
adjacent cells is purified and metal ions are concentrated  in the
cathode cell, with sulfates, chlorides, etc., concentrated  in the
anode cell.  At the outlet end of the cell stack, streams are
drawn off from the individual cells either as the purified water or
as concentrate for recovery or for further treatment.

Figure 7-61 illustrates the operation of a seven chamber conven-
tional electrodialysis cell.  In large electrodialysis installa-
tions, two or more stacks are linked in series.  The dilute
effluent from the first stage is passed through an identical
second stage, and so forth, with the effluent from the final
stage reaching the desired concentration.

Application of_ Conventional Electrodialysis

Electrodialysis has been shown to be an effective method for concen-
trating rinse waters to a high percentage of bath strength.  Nickel,
copper, cyanide, chromic acid, iron and zinc can be removed from
process wastes by electrodialysis.  The natural evaporation taking
place in a plating bath will often be sufficient to allow electro-
dialysis to be used to close the loop without the addition of an
evaporator.  Electrodialysis is used to treat spent chromic acid,
copper, cyanide, and other solutions.  Chromic acid solution con-
taining trivalent chromium, iron, zinc, copper, etc., enters the
anode compartment of the electrodialysis cell, where the applica-
tion of an electrical potential causes the copper, zinc, and tri-
valent chromium to pass through the cation permeable membrane to
the catholyte solution.  At the same time, some of the trivalent
chromium passes through the anion-permeable membrane to the anode
solution where it is oxidized to hexavalent chromium at the anode.
The result is a decreased concentration of metal ions in the solu-
tions between the cation-permeable membrane and the anion-permeable
membrane.

At the time of the sampling visit, conventional electrodialysis was
being used by plant ID 20064 as a means of concentrating and re-
covering chromic acid etch solution.  Electrodialysis can be com-
bined with an existing treatment system for recovery of metals, or
it can be used with other treatment to effect recirculation of
rinse water.   Many possibilities exist for electrodialysis and with
recent developments in membrane materials and cathode design and
                               Vll-103

-------
  PURIFIED
   WATER
CONCENTRATE-
                         — 1 CATHODE
(-)'
i
                     ©
                   DIM
  i©^
                     ^ i
                     ©
                                       •WASTE WATER
                 NS^..^ W  &

                    i o"  ™
                            ANODE
                      FIGURE 7-61


            MECHANISM OF THE ELECTRODIALYTSC PROCESS.
                          VI1-104

-------
increased knowledge of their applications, it may become a major
form of treatment for metals.

Performance of Conventional Electrodialysis

Little information is available on performance for treatment of
chromic acid; however, information is available on copper cyanide
performance.  Copper cyanide rinse water is treated in an electro-
dialysis unit for return of the concentrated chemicals to the pro-
cess bath.  The copper cyanide chemicals in the rinse water can be
concentrated to slightly more than 70 percent of the bath strength.
For most copper cyanide plating, this concentration may be suffi-
cient to permit the direct return of all chemicals to the process-
ing operation.  Figure 7-62 shows an electrodialysis recovery system,

Demonstration Status

Three metal finishing plants in our data base indicate the use of
electrodialysis.  These plant ID'S are;  20064, 20069, and 41003.

REVERSE OSMOSIS

The process of osmosis involves the passage of a liquid through a
semipermeable membrane from a dilute to a more concentrated solution,
Reverse osmosis (RO) is an operation in which pressure is applied
to the more concentrated solution, forcing the permeate to diffuse
through the membrane and into the more dilute solution.  This
filtering action produces a concentrate and a permeate on opposite
sides of the membrane.  The concentrate can then be further treated
or returned to the original operation for continued use, while the
permeate water can be recycled to the rinse tanks.  Figure 7-63
represents a reverse osmosis system.

As illustrated in Figure 7-64, there are three basic configurations
used in commercially available RO modules:  tubular, spiral-wound,
and hollow fiber.  All of these operate on the principle described
above, the only difference being their mechanical and structural
design characteristics.

The tubular membrane module utilizes a porous tube with a cellu-
lose acetate membrane-lining.  A common tubular module consists
of a length of 2.54 cm (1 inch) diameter tube wound on a support-
ing spool and encased in a plastic shroud.  Feed water is driven
into the tube under pressures varying from 40.8 - 54.4 atm (600-
800 psi).  The permeate passes through the walls of the tube and
is collected in a manifold while the concentrate is drained off at
the end of the tube.  A less widely used tubular RO module uses a
straight tube contained in a housing, under the same operating
conditions.
                               VII-105

-------
 DRAG-OUT
               DRAG-OUT

             I	1

             I            i
                                     •-^-DRAG-OUT
PARTS

PLATING TANK



RINSE #1



RINSE #2

PARTS

I
f
r
                 FEED    I
             ' ------  '
                            r
CONCENTRATE |
1 EL
L__Lj
FEED L,
/ —
ECr
r— 1
ERODIALYZER STA
i 	 1 i — 1
-1
- J
_ 	

r -
L- .
	

, , ..^. . ,.
CK f 1 |
l 1 |
(T FEEDj
                                     -DEIONIZED WATER
     -DEIONIZED WATER
                    FIGURE 7-62


           ELECTRODIALYSIS RECOVERY SYSTEM

-------
                                    MACROMOLECULES
                                          AND
                                        SOLIDS
MEMBRANE
                                                       P = 450 PS I
                                  WATER
                                        MEMBRANE CROSS SECTION.
                                        IN TUBULAR, HOLLOW FIBER,
                                        OR SPIRAL-WOUND CONFIGURATION
           PERMEATE (WATER)
          •  •
        •O SALTS OR SOLIDS


        •  WATER MOLECULES
                        FIGURE 7-63
           SIMPLIFIED REVERSE OSMOSIS SCHEMATIC
                                                        CONCENTRATE
                                                          (SALTS)
                          VII-107

-------
                                                                   SPIRAL MODULE
                                             PERMEATE   ADHESIVE BOUND   |        ct«1B*Tt
                                       fEEO f
                                        ftf.0
                                           O-RING MEMBftANE
                                                                BACKING MATERIAL

                                                               SPACER
                                                      SPIRAL MEMBRANE MODULE
Porout Support Tub*
  with Membrarw
         Brackish
 o - o • —~  Water
*°'%°   F«d Flow
fa
                    Product Water P»rme«t» Flow
                                                      ' Brim
                                                       Concentrita
                                                       Flow
                     TUBULAR REVERSE OSMOSIS MODULE
            CONCENTRATE
   SNAP RING     OUTLET
                                                             OPEN ENDS
                                                             OF FIBERS
                                                                                EPOXY
                                                                                   SHEET
                                                                                       POROUS
                                                                                     BACK-UP DISC
                                                                                       SNAP RING
  END PLATE
                         FIBER
                                       SHELL
                                                                       •0' RING SEAL
                                                          POROUS FEED             END PLATE
                                                        DISTRIBUTOR TUBE
                          HOLLOW FIBER MODULE
                                             FIGURE  7-64

                         REVERSE  OSMOSIS  MEMBRANE  CONFIGURATIONS

                                                VII-108

-------
Spiral-wound membranes consist of a porous  backing  sandwiched be-
tween two cellulose acetate membrane  sheets and  bonded along three
edges.  The fourth edge of the composite  sheet  is  attached to a
large permeate collector tube.  A spacer  screen  is  then placed on
top of the membrane sandwich and the  entire stack  is rolled around
the centrally located tubular permeate  collector.   The rolled up
package is inserted into a pipe able  to withstand  the high operat-
ing pressures employed in this process, up  to  54.4  atm (800 psi)
with the spiral-wound module.  When the system  is  operabing, the
pressurized product water permeates the membrane and flows through
the backing material i:o i.he create a I collector  tube.   The concen-
trate is drained off at the end of the  container pipe and can be
reprocessed or sent to further treatment  facilities.

The hollow fiber membrane configuration is  made  up  of a bundle of
polyamide fibers of approximately 0.0076  cm (3 mils) OD and 0.0043
cm (1.7 mils) ID.  A commonly used hollow fiber  module contains
several hundred thousand of the fibers  placed  in a  long tube,
wrapped around a flow screen, and rolled  into  a  spiral.  The fibers
are bent in a U-shape and their ends  are  supported  by an epoxy
bond.  The hollow fiber unit is operated  under  27.2 atm (400 psi),
the feed water being dispersed from the center of  the module through
a porous distributor tube.  Permeate  flows  through  the membranes
to the fiber interiors and is collected at  the ends of the fibers.

The hollow fiber and sprial-wound modules have a distinct advantage
over the tubular system in that they  are  able  to load a very large
membrane surface area into a relatively small  volume.  However,
these two membrane types are much more  susceptible  to fouling than
the tubular system, which has a larger  flow channel.  This charac-
teristic also makes the tubular membrane  much  easier to clean and
regenerate than either the spiral-wound or  hollow  fiber modules.
One manufacturer claims that their helical  tubular  module can be
physically wiped clean by passing a soft  porous  polyurethane plug
under pressure through the module.

Application and Performance

The largest industrial wastewater application  of reverse osmosis
has been in plating to recover nickel and rinse  water from nickel
deposition rinses.  Reverse osmosis is  used to close the loop be-
tween plating and rinsing operations  in the metal  finishing indus-
try.   The overflow from the first rinse in  a countercurrent setup
is directed to a reverse osmosis unit, where it  is  separated into
two streams.   The concentrated stream contains dragged out pro-
cess  chemicals and is returned to the process  bath  to replace the
loss  of solution due to evaporation and dragout.   The dilute stream
(the  permeate)  is routed to the last  rinse  tank  to  provide water
for the rinsing operation.  The rinse flows from the last"tank to
the first tank and the cycle is complete.
                              VI1-109

-------
The closed-loop system described above may  be  supplemented by the
addition of a vacuum evaporator after the RO unit  in  order to further
reduce the volume of reverse osmosis concentrate.   The  evaporated
vapor can be condensed and returned to the  last  rinse tank or sent
on for further treatment.  Another variation is  to  increase the rate
of evaporation in the process bath to make  room  for reverse osmosis
concentrate.

It has been shown that RO can generally be  applied  to most acid
metal baths with a high degree of performance, providing  that the
membrane unit is not overtaxed.  The limitations most critical here
are the allowable pH range and maximum operating pressure for each
particular configuration.  Adequate prefiltration  is  also essential.
In metal finishing, reverse osmosis has been found  attractive for
recovery in Watts-type nickel, nickel sulfamate, copper pyrophosphate,
nickel fluoborate, zinc chloride, copper cyanide,  zinc  cyanide, and
cadmium cyanide systems.  Application to chromic acid and very high
pH systems has not been successful.

Plant 33065 has a reverse osmosis unit on its  nickel  plating line.
The sampling results of the raw input, permeate, and  concentrate
are shown below.
Parameter           Input

TSS                  1.0
Copper               .617
Nickel               276.
Chromium, Total      .050
Zinc                 .846
Cadmium             <.005
Tin                  .417
Lead                <,01
                                   Permeate

                                    2.0
                                    .092
                                    81.
                                    .033
                                    .159
                                   <.005
                                    .375
Concentrate
 .067
 20,700
 .051
 17.6
 .006
 .500
 .021
One manufacturer claims that several RO units are  being  used  to
dewater sludges generated by photographic processes.   Reverse
osmosis has also been effective in removing  zinc from  diazo solu-
tions in laboratory experiments.  Another company  has  demonstrated
the usefulness of RO in removing cutting oils and  machining cool-
ants from wastewater streams in a pilot plant operation.

Several new membrane materials are under development.  A Japanese
firm has conducted experiments with a new RO membrane  consisting of
a polybenzimidazolone (PBIL) polymer.  The manufacturer  claims  that
it can handle a pH range from 1 to 12, temperatures  as high as  60°C
and is resistant to oxidation by chromic acid.  Test results  for
acid copper plating have been encouraging.   In  contrast,  perform-
ance of a polybenzimidazole (PBI) membrane has  been  disappointing.
Another membrane is being considered for treatment of  cyanide
plating baths and has shown pH tolerance in  the 1  to 13  range.   It
is made up of a crosslinked polyethyleneimine structure  and is
                             VII-110

-------
claimed to exhibit excellent stability  and  RO  performance.   A
polyamide composite membrane also shows promise  for  both acid and
alkaline cyanide service, and a polyfurfuryl alcohol hollow fiber
composite membrane is effective for acid  copper  solutions.   The only
membranes readily available commercially  are the  three  described
earlier, and their overwhelming use has been for  the recovery of
various acid metals plating baths.

Advantages and Limitations

The major advantage of reverse osmosis  for  handling  process efflu-
ents is its ability to concentrate dilute solutions  for recovery
of salts and chemicals with low power requirements.   No latent heat
of vaporization or fusion is required for effecting  separations;
the main energy requirement is for a high pressure pump.   It re-
quires relatively little floor space for  compact, high  capacity
units, and it exhibits good recovery and  rejection rates for a
number of typical process solutions.  Capital  and operating costs
are relatively low.  A limitation of the  reverse  osmosis process
for treatment of process effluents is its limited temperature range
for satisfactory operation.  For cellulose  acetate systems, the
preferred limits are 18.3 to 29.4 degrees C (65  to 85 degrees F);
higher temperatures will increase the rate  of  membrane  hydrolysis
and reduce system life, while lower temperatures  will result in
decreased fluxes with no damage to the  membrane.  Another limit-
ation is inability to handle certain solutions.   Strong oxidizing
agents, strongly acidic or basic solutions, solvents, and other
organic compounds can cause dissolution of  the membrane.   Poor
rejection of some compounds such as borates and  low  molecular weight
organics is another problem.  Fouling of membranes by slightly
soluble components in solution or colloids  has caused failures, and
fouling of membranes by feed waters with high  levels of suspended
solids can be a problem.  A final limitation is  inability to treat
or achieve high concentration with some solutions.   Some concen-
trated solutions may have initial osmotic pressures  which are so
high that they either exceed available  operating  pressures  or are
uneconomical to treat.

Operational Factors

Reliability;  Very good so long as the  proper  precautions are taken
to minimize the chances of fouling or degrading  of the  membrane.
Sufficient testing of the waste stream  prior to  application of an
RO system will provide the information  needed  to  insure a success-
ful application.

Maintainability;  Membrane life is estimated to  fall between 6
months and 3 years, depending on the use of the  system.  Down time
for flushing or cleaning is on the order of 2  hours  as  often as
once each week; a substantial portion of maintenance time must be
spent on cleaning any prefilters installed  ahead  of  the reverse
osmosis unit.


                             Vli-lll

-------
Solid Waste Aspects;  In a closed loop system utilizing  RO  there
is a constant recycle of concentrate and a minimal amount of  solid
waste.  Prefiltration eliminates many solids before  they reach  the
module and helps keep the buildup to a minimum.  These solids re-
quire proper disposal.

Demonstration Status

There are presently at least one hundred reverse osmosis wastewater
applications in a variety of industries.  In addition to these,
there are thirty to forty units being used to provide pure  process
water for several industries.

Despite the many types and configurations of membranes,  only  the
spiral-wound cellulose acetate membrane has had widespread  success
in commercial applications.  RO is used in 8 plants  in the  present
data base and these are identified in Table 7-19.

PEAT ADSORPTION

Peat moss is a rather complex material with lignin and cellulose
as major constituents.  These constituents, particularly lignin,
bear polar functional groups, such as alcohols, aldehydes,  ketones,
acids, phenolic hydroxides and ethers, that can be involved in
chemical bonding.  Because of the polar nature of this material,
its adsorption of dissolved solids such as transition metals  and
polar organic molecules is quite high.  These properties have led
to the use of peat as an agent for the purification  of industrial
wastewater.

Peat adsorption is a "polishing" process which can achieve  very low
effluent concentrations for several pollutants.  If  the  concentra-
tions of pollutants are above 10 mg/1, then peat adsorption must be
preceded by pH adjustment and settling.  The wastewater  is  then
pumped into a large metal chamber called a kier which contains a
layer of peat through which the waste stream passes *  The water
flows to a second kier for further adsorption.  The  wastewater is
then ready for discharge.  This system may be automated  or  manu-
ally operated.

                          Table 7-19
        Metal Finishing Plants Employing Reverse Osmosis

                     04236           33065
                     18534           38040
                     30166           38050
                     31032           43003
                              VII-112

-------
Application and Performance

Peat adsorption can be used in metal finishing plants  for  removal
of residual dissolved metals from clarifier effluent.   Peat  moss
may be used to treat wastewaters containing heavy metals such  as
mercury, cadmium, zinc, copper, iron, nickel, chromium, and  lead,
as well as organic matter such as oil, detergents,  and dyes.   Peat
adsorption could be used in metal finishing industries, coil coat-
ing plants, porcelain enameling, battery manufacturing plants,
copper products manufacturing facilities, photographic plants,
textile manufacturing, newsprint production facilities, and  other
industries.  Peat adsorption is currently used commercially  at  a
textile plant, a newsprint facility, and a metal reclamation
operation.

The following table contains performance figures obtained  from  pilot
plant studies.  Peat adsorption was preceded by pH  adjustment  for
precipitation and by clarification.

Pollutant      Before Treatment (mg/1)       After  Treatment  (mg/1)

   Pb               20.0                          0.025
   Sb               2.5                           0.9
   Cu               250.0                         0.24
   Zn               1.5                           0.25
   Ni -             2.5                           0.07
   Cr b             35,000.0                     <0.04
   CN               36.0                          0.7
   Hg              >1.0                           0.02
   Ag              >1.0                           0.05

In addition, pilot plant studies have shown that complexed metal
wastes, as well as the complexing agents themselves, are removed
by contact with peat moss.  Therefore, peat adsorption could be
applied to printed circuit board manufacturing, which  uses com-
plexing agents extensively.

Advantages and Limitations

The major advantages of the system include its ability to  yield low
pollutant concentrations, its broad scope in terms  of  the  pollutants
eliminated, and its capacity to accept wide variations of  wastewater
composition.

However, the cost of purchasing, storing, and disposing of the  peat
moss could limit the use of this system.  The necessity for  regular
replacement of the peat may lead to high operation  and maintenance
                              VIl-113

-------
costs.  Also, the pH adjustment must  be  altered according to the
composition of the waste stream.

Operational Factors

Reliability;  The peat moss adsorption system has only recently
been developed, and the question of reliability is not yet answered,
Although the manufacturer reports  it  to  be  a highly reliable system,
operating experience is needed to  verify the reliability.

Maintainability;  The peat moss used  in  this process soon exhausts
its capacity to adsorb pollutants.  At that time, the kiers must
be opened, the peat removed, and fresh peat placed inside.
Although this procedure is easily  and quickly accomplished, it
must be done at regular intervals, or the system's efficiency
drops drastically.

Solid Waste Aspects;  After removal from the kier, the spent peat
must be eliminated.  If incineration  is  used,  precautions should
be taken to insure that those pollutants removed from the water
are not released again in the combustion process.  Presence of
sulfides in the spent peat, for example, will give rise to sulfur
dioxide in the fumes from burning.  The  peat is a very stable
material if not exposed to an extreme pH below three or above
eight.

Demonstration Status

Only three commercial adsorption systems are currently in use
in the United States at a textile  manufacturer, a newsprint
facility, and a metal reclamation  firm.

No data have been reported showing the use  of peat adsorption in
any metal finishing plants.  Its only commercial applications are
as stated above.

INSOLUBLE STARCH XANTHATE

Insoluble starch xanthate (ISX) is essentially an ion exchange
medium used to remove dissolved heavy metals from wastewater.  ISX
is formed by reacting commercial cross-linked starch with sodium
hydroxide and carbon disulfide.  Magnesium  sulfate is also added
as a stabilizer and to improve sludge settling.

ISX acts as a cationic ion exchange material removing the heavy
metal ions and replacing them with sodium and magnesium.  The
starch has good settling characteristics, good filtering charac-
teristics, and is well suited for  use as a  filter precoat.  ISX
can be added as a slurry for continuous  treatment operations,
in solid form for batch treatments and as a precoat to a filter.
                              VII-114

-------
The ISX process is effective for removal of all uncomplexed
metals, including hexavalent chromium, and also some complexed
metals such as the copper-ammonia complex.  The removal of hexa-
valent chromium is brought about by lowering the pH to below 3
and subsequent raising of it above 7.  The hexavalent chromium
is reduced by the ISX at the acid pH and is removed at the alka-
line pH as chromium starch xanthate or chromic hydroxide.

Presently, ISX is being used in two metal finishing establish-
ments.  One of the plants utilizes the ISX process as a polishing
filter and claims to reduce levels of metals in the effluent of
their clarifier from 1 mg/1 to .020 mg/1.  The other plant (ID
27046), which was visited and sampled, uses the ISX process to
recycle rinse waters on their cleaning line and nickel, copper,
and solder plating lines.  The results of the sampling are lis-
ted below.
     Solder Line

     Input     Output
      To     From
     Filter    Filter
  Nickel Line

Input     Output
 To        From
Filter    Filter
Cu
Pb
Sn
Zn
Ni
Fe
.42
.56
2.0
.092
—
—
.41
.53
1.5
.083
-
—
                         .24
                         .047
                         552.
          .24
          .040
          547.
   Cleaning Line

Input     Output
 To        From
Filter    Filter
.43


.167

.38
.39


.126

.26
As shown by the data, the ISX was not removing a high percentage
of metal.  Its main purpose was to keep contaminants from build-
ing up to a point where the water would not be reusable.

SULFIDE PRECIPITATION

Hydrogen sulfide or soluble sulfide salts such as sodium sul-
fide are used to precipitate many heavy metal sulfides.  Since
most metal sulfides are even less soluble than metal hydroxides
at alkaline pH levels, greater heavy metal removal can be ac-
complished through the use of sulfide rather than hydroxide
as a chemical precipitant prior to sedimentation.  The solu-
bilities of metallic sulfides are pH dependent and are shown
in Figure 7-65.

Sampling data from three industrial plants using sulfide preci-
pitation are presented in Table 7-20.  Concentrations are given
in mg/1.
                              Vll-115

-------
    10





    10





    10°





   10'





_ 10"

I—I
\


I 10°


iH
m
            -O

            0*
             o
             w
                10
            0   ID'7
            c
            o
            •**


            2   I0"
            jj


            §   10"

            o
               10
                 "°
  10





  10




  10
                •II
                -13
                       T	1	1
      2   3
                                                 CoS
                                                       i    i
                                5   6    7   6    9   10   II   12   13

                                          PH
 NOTE;    Plotted data  for metal sulfides based on experimental data  listed

           in Seidell's  solubilities.




                                FIGURE  7-b5



COMPARATIVE  SOLUBILITIES  OF METAL SULFIDES AS A FUNCTION  OF pH
                                  VII-116

-------
                         Table 7-20
                 Sampling Data From Sulfide
            Precipitation/Sedimentation Systems
Data Source
Treatment
  Reference 1

  Lime, FeS, Poly-
  Electrolyte ,
  Settle, Filter
          Reference 2

          Lime, FeS, Poly-
          Electrolyte ,
          Settle, Filter
                    Reference

                    NaOH, Ferric
                    Chloride, NaS,
                    Clarify (1 stage)
Cr, T
Cu
Fe
Ni
Zn

Reference:
  Raw

5.0-6.8
  25.6
  32.3

  .52

  39.5
Eff .

8-9
<.01
<.04

.10

<.07
Raw

7.7
.022
2.4

108
.68
33.9
                                             Eff.

                                             7.38
                                             <.020
0.6
          Raw

          27
          11.4
          18.3
          .029
          .060
Eff.

6.4
<.005
<.005
.003
.009
1.   Treatment of Metal Finishing Wastes by Sulfide Precipitation,
     EPA Grant No. S804648010
2.   Industrial Finishing, Vo. 35, No. 11, Nov. 1979, p. 40 (Raw
     waste sample taken after chemical addition).
3.   Visit Plant 27045.  Concentrations are two day averages.

In all cases except iron, effluent concentrations are below 0.1 mg/1
and in many cases below 0.01 mg/1 for the three plants studied.

Sampling data from several chlorine/caustic inorganic chemicals
manufacturing plants using sulfide precipitation reveal effluent
mercury concentrations varying between 0.009 and 0.03 mg/1.  (Cal-
span Report No. ND-5782-M-72).  As can be seen in Figure 7-65, the
solubilities of PbS and Ag2S are lower at alkaline pH levels than
Bench scale tests conducted on several types of metal finishing
wastewater (Centec Corp; EPA Contract 68-03-2672) indicate that
metals removal to levels of less than 0.05 mg/1 and in some
cases less than 0.01 mg/1 are common in systems using sulfide
precipitation followed by clarification.  Some of the bench scale
data, particularly in the case of lead, does not support such low
effluent concentrations.  However, no suspended solids data was
provided in these studies.  TSS removal is a reliable indicator
of precipitation/sedimentation system performance.  Lack of this
                              VII-117

-------
data makes it difficult to fully evaluate  the  bench  tests  and in-
sufficient solids removal can result  in high metals  cncentrations .
Lead is consistently removed to very  low levels  (less  than 0.02
mg/1 ) in systems using hydroxide precipitation and sedimentation.
Therefore one would expect even lower effluent concentrations of
lead resulting from properly operating sulfide precipitation  sys-
tems due to the lower solubility of the lead sulfide compound.

Of particular interest is the ability of the_gferrous sulfide  pro-
cess to precipitate hexavalent chromium (Cr  ) without  prior  re-
duction to the trivalent state as is  required  in  the hydroxide
process, although the chromium is still precipitated as the hy-
droxide.  When ferrous sulfide is used as  the  precipitant, iron
and sulfide act as reducing agents for the hexavalent chromium.
2FeS + 7H20  2Fe(OH)3 + 2Cr(OH)3 + 2S
                                                        2OH
In this case the sludge produced consists mainly of ferric  hydrox-
ides and chromic hydroxides.  Some excess hydroxyl ions are pro-
duced in this process, possibly requiring a downward re-adjustment
of pH to between 8-9 prior to discharge of the treated effluent.

Advantages and Limitations

The major advantage of the sulfide precipitation process  is that
due to the extremely low solubilites of most metal sulfides, very
high metal removal efficiences can be achieved.  Also, the  sulfide
process has the ability to remove chromates and dichromates with-
out preliminary reduction of the chromium to its trivalent  state.
In addition, it will precipitate metals complexed with most com-
plexing agents.  However, care must be taken to maintain  the pH
of the solution above approximately 8 in order to prevent the gen-
eration of toxic hydrogen sulfide gas.  For this reason ventilation
of the treatment tanks may be a necessary precaution in some in-
stallations.  The use of ferrous sulfide virtually eliminates the
problem of hydrogen sulfide evolution, however.  As with  hydroxide
precipitation, excess sulfide must be present to drive the
precipitation reaction to completion.  Since sulfide itself is
toxic, sulfide addition must be carefully controlled to maximize
heavy metals precipitation with a minimum of excess sulfide to
avoid the necessity of posttreatment .  At very high excess  sul-
fide levels and high pH , soluble mercury-sulf ide compounds  may
also be formed.  Where excess sulfide is present, aeration  of
the effluent stream can aid in oxidizing residual sulfide to the
less harmful sodium sulfate (Na-So.).  The cost of sulfide  pre-
cipitants is high in comparison with hydroxide precipitating agents,
and disposal of metallic sulfide sludges may pose problems.
Speculation is that with improper handling or disposal of sulfide
precipitates, hydrogen sulfide may be released to the atmosphere
                             VTI-118

-------
creating a potential toxic hazard, toxic metals may be leached
out into surface waters, and sulfide might oxidize to sulfate and
release dilute sulfuric acid to surface waters.  An essential
element in effective sulfide precipitation is the removal of
precipitated solids from the wastewater to a site where reoxidation
and leaching are not likely to occur.

Operational Factors

Reliability;  The reliability of sulifde precipitation is high,
although proper monitoring, control, and pretreatment to re-
move interfering substances is required.

Maintainability:  The major maintenance needs involve periodic
upkeep of monitoring equipment, automatic feeding equipment,
mixing equipment, and other hardware.  Removal of accumulated
sludge is necessary for efficient operation of sulfide pre-
cipitation systems.

Solid Waste Aspects;  Solids which precipitate out are removed
in a subsequent treatment step.  Ultimately, the solids must be
properly disposed of.  There is disagreement over the accepta-
bility of sulifde and other sludges for landfill, as discussed
above.

Demonstration Status

Full scale commercial sulfide precipitation units are in opera-
tion at numerous installations, including several plants in the
Metal Finishing Category.

FLOTATION

Flotation is the process of causing particles such as metal hydro-
xides or oil to float to the surface of a tank where they can be
concentrated and removed.  This is accomplished by releasing gas
bubbles which attach to the solid particles, increasing their
buoyancy and causing them to float.  In principle, this process
is the opposite of sedimentation.  Figure 7-66 shows one type of
flotation system.  Flotation processes that are applicable to
oil removal are discussed in the subsection entitled "Treatment
of Oily Wastes and Organics".
                              VII-119

-------
OILY WATER
INFLUENT
                                           WATER
                                           DISCHARGE
                                 OVERFLOW
                                 SHUTOFF
                                 VALVE
                                                             EXCESS
                                                             AIR OUT
                                                             LEVEL
                                                             CONTROLLER
      TO SLUDGE
      TANK   •*
                                FIGURE  7-66

                        DISSOLVED AIR  FLOTATION-
                                  VI1-120

-------
Flotation is  used primarily in the treatment of wastewater  con-
taining  large quantities of industrial wastes that carry  heavy
loads  of finely divided suspended solids.  Solids having  a  spe-
cific  gravity only slightly greater than 1.0, which would require
abnormally long sedimentation times may be removed in much  less
time by  flotation.

This process  may be performed in several ways:  foam, dispersed
air, dissolved air, gravity, and vacuum flotation are the most
commonly used techniques.  Chemical additives are often used  to
enhance  the performance of the flotation process.

The principal difference between types of flotation is the  method
of generation of the minute gas bubbles, usually air, in  a  suspen-
sion of  water and small particles.  The use of chemicals  to improve
the efficiency may be employed with any of the basic methods.  The
following paragraphs describe the different flotation techniques
and the  method of bubble generation for each process.

Foam Flotation - Foam flotation is based on the utilization of
differences in the physiochemical properties in various particles.
Wettability and surface properties affect the particles'  ability  to
attach themselves to gas bubbles in an aqueous medium.  In  froth
flotation, air is blown through the solution containing flotation
reagents.  The particles with water repellant surfaces stick to
air bubbles as they rise and are brought to the surface.  A mineral-
ized froth layer with mineral particles attached to air bubbles  is
formed.   Particles of other minerals which are readily wetted by
water do not stick to air bubbles and remain in suspension.

Dispersed Air Flotation - In dispersed air flotation, gas bubbles
are generated by introducing the air by means of mechanical
agitation with impellers or by forcing air through porous media.

Dissolved Air Flotation - In dissolved air flotation, bubbles are
produced as a result of the release of air from a  supersaturated
solution under relatively high pressure.  There are two types of
contact  between the gas bubbles and particles.  The first type  is
predominant in the flotation of flocculated materials and
involves the entrapment of rising gas bubbles  in the  flocculated
particles as they increase in size.  The bond between the bubble
and particle is one of physical capture only.  The second type  of
contact  is one of adhesion.  Adhesion results  from the  inter-
molecular attraction exerted at the interface between the solid
particle and gaseous bubble.

Vacuum Flotation - This process consists of saturating  the  waste-
water with air either 1) directly in an aeration tank,  or 2) by
permitting air to enter on the suction of a wastewater  pump.  A
partial  vacuum is applied, which causes  the dissolved  air to come
out of solution as minute bubbles.  The bubbles  attach  to solid
particles and rise to the surface to form a scum blanket, which
is normally removed by a skimming mechanism.   Grit  and  other heavy
                             VII-121

-------
solids that settle  to  the  bottom  are  generally raked to a central
sludge pump for removal.   A  typical vacuum flotation unit consists
of a covered cylindrical tank  in  which  a partial vacuum is main-
tained.  The tank is equipped  with  scum and sludge removal mechan-
isms.  The floating material  is continuously swept to the tank
periphery, automatically discharged into a scum trough, and removed
from the unit by a  pump also  under  partial vacuum.  Auxiliary
equipment includes  an  aeration tank for saturating the wastewater
with air, a tank with  a short  retention time for removal of large
bubbles, vacuum pumps, and sludge and scum pumps.

Application and Performance

Bench scale experiments have  shown  foam flotation  to be very
effective in removing  precipitated  copper, lead, arsenic, zinc,
and fluoride.  The  following  table  shows the results.   A sodium
lauryl sulfate (NLS) surfactant and a flocculant were  used in each
case, and pollutant concentrations were between 10 and 500 mg/1.

                 FOAM  FLOTATION PERFORMANCE

                                                   Residual
                                   Optimum        Concentration,
     Pollutant      Reagent           pH          	mg/1	

     Copper         Fe(OH) -NLS       7.0               0.1
     Lead           Fe(OH)^-NLS       6.5               0.1
     Arsenate       Fe(OH):r-NLS       4-5               0.1
     Zinc           Al(OH):;-NLS     8.0-8.5             0.2

     Note:     NLS  is  sodium  lauryl sulfate

The primary variables  for  flotation design are pressure, feed
solids concentration,  and  retention period.   The effluent suspended
solids decrease and the concentration of solids in the float
increases with increasing  retention period.   When  the  flotation
process is used primarily  for  clarification, a retention period  of
20 to 30 minutes is adequate  for  separation and concentration.

Advantages and Limitations

Some advantages of  the flotation  process are the high  levels of
solids separation achieved in  many applications, the relatively
low energy requirements, and  the  air  flow adjustment capability
to meet the requirements of treating  different waste types.
Limitations of flotation are that it  often requires addition of
chemicals to enhance process performance,  and it generates large
quantities of solid waste.
                             VII-122

-------
Operational Factors
Reliability;   The reliability of a flotation system  is  normally
high and is governed by the sludge collector mechanism  and  by  the
motors and pumps used for aeration.

Maintainability;  Routine maintenance is required on  the pumps and
motors.  The  sludge collector mechanism is subject to possible cor-
rosion or breakage and may require periodic replacement.

Solid Waste Aspects;  Chemicals are commonly used to  aid the flo-
tation process.   These chemicals, for the most part,  function  to
create a surface or a structure that can easily absorb  or entrap
air bubbles.   Inorganic chemicals, such as the aluminum and ferric
salts and activated silica, can be used to bind the particulate
matter together  and, in so doing, create a structure  that can  easily
entrap air bubbles.  Various organic chemicals can be used  to  change
the nature of either the air-liquid interface or the  solid-liquid
interface, or both.  These compounds usually collect  on the inter-
face to bring about the desired changes.  The added chemicals  plus
the particles in solution combine to form a large volume of sludge
which must be further treated or properly disposed.

Demonstration Status

Flotation is  a fully developed process and is readily available
for the treatment of a wide variety of industrial waste streams.
It is used in 29 plants in the present data base and  these
are identified in Table 7-21.

                         Table 7-21
         Metal Finishing Plants Employing Flotation
               01063
               04892
               05050
               11704
               12076
               12080
               12091
               14062
               15058
               20106
20157
20159
20165
20247
20254
30150
30151
30153
30516
31067
31068
33117
33120
33127
33180
33692
38031
41097
41151
                               VII-123

-------
MEMBRANE FILTRATION
Membrane filtration is a technique for removing precipitated
heavy metals from a wastewater stream.  It must therefore  be
preceded by those treatment techniques which will properly pre-
pare the wastewater for solids removal.  Typically, a membrane
filtration unit is preceded by cyanide and chromium pretreatment
as well as pH adjustment for precipitation of the metals.  These
steps are followed by addition of a proprietary chemical reagent
which causes the metal precipitate to be non-gelatinous, easily
dewatered, and highly stable.  The resulting mixture of pretreated
wastewater is continuously recirculated through a filter module
and back into a recirculation tank.  The filter module contains
tubular membranes.  While the reagent-metal precipitates mix-
ture flows through the inside of the tubes, the water and  any
dissolved salts permeate the membrane.  The permeate, essentially
free of precipitate, is alkaline, non-corrosive, and may be safely
discharged to sewer or stream.  When the recirculating slurry
reaches a concentration of 10 to 15 percent solids, it is  pumped
out of the system as sludge.

Application and Performance

Membrane filtration can be used in metal finishing in addition
to sedimentation to remove precipitated metals and phosphates.
Membrane filtration systems are being used in a number of  indus-
trial applications, particularly in the metal finishing industry
and have also been used for heavy metals removal in the paper
industry.  They have potential application in coil coating,
porcelain enameling, battery, and copper and copper alloy  plants.

The permeate is guaranteed by one manufacturer to contain  less
than the effluent concentrations shown in the following table,
regardless of the influent concentrations.  These claims have
been largely substantiated by the analysis of water samples at
various plants including those shown for comparison in the table.
WASTEWATER CONSTITUENT
                    MEMBRANE FILTER EFFLUENT;  mg/1

               Guarantee  Plant #19066      Plant #31022
                                    Raw
                                 Treated
                          Raw
Treated
Aluminum
Chromium,
Chromium,
Copper
Iron
Lead
Cyanide
Nickel
Zinc
TSS
hexavalent
total
0.5
0.03
0.02
0.1
0.1
0.05
0.02
0.1
0.1
0.46
4.13
18.8
288
.652
<.005
9.56
2.09
632
0.01
0.018
0.043
0.3
0.01
<.005
.017
.046
<0.1
5.25
98.4
8.00
21.1
0.288
<.005
194.
5.00
13.0
<.005
.057
.222
.263
0.01
<.005
.352
.051
8.0
                                VII-124

-------
Advantages and Limitations

A major advantage of the membrane filtration system  is that
installation can utilize most of the conventional end-of-pipe
system that may already be in place.  Also, the sludge is highly
stable in an alkaline state.  Removal efficiencies are excellent,
even with sudden variation of pollutant input rates.  However,
the effectiveness of the membrane filtration system  can be limited
by clogging of the filters.  Because a change in the pH of the
waste stream greatly intensifies the clogging problem, the pH must
be carefully monitored and controlled.  Clogging can force the
shutdown of the system and may interfere with production.

Operational Factors

Reliability;  Membrane filtration has been shown to  be a very reliable
system, provided that the pH is strictly controlled.  Improper pH
can result in the clogging of the membrane.  Also, surges in the
flow rate of the waste stream must be eliminated in  order to
prevent solids from passing through the filter and into the effluent.

Maintainability;  The membrane filters must be regularly monitored,
and cleaned or replaced as necessary.  Depending on  the composition
of the waste stream and its flow rate, cleaning of the filters may be
required quite often.  Flushing with hydrochloric acid for 6-24 hours
will usually suffice.  In addition, the routine maintenance of pumps,
valves, and other plumbing is required.

Solid Waste Aspects;  When the recirculating reagent-precipitate
slurry reaches 10 to 15 percent solids, it is pumped out of the
system.  It can then be disposed of directly or it can undergo a
dewatering process.  The sludge's leaching characteristics are
such that the state of South Carolina has approved the sludge for
landfill, provided that an alkaline condition be maintained.  Tests
carried out by the state indicate that even at the slightly acidic
pH of 6.5, leachate from a sludge containing 2600 mg/1 of copper
and 250 mg/1 of zinc contained only 0.9 mg/1 of copper and 0.1 mg/1
of zinc.

Demonstration Status

There are approximately twenty membrane filtration systems
presently in use by the metal finishing and other industries.
Bench scale and pilot studies are being run in an attempt to
expand the list of pollutants for which this system  is known
to be effective.

Membrane  filtration is used in 7 plants in the present data base:
Plant ID's 02032, 04690, 15193, 19066, 31022, 34050, and 37042.
                               VII-125

-------
TREATMENT OF_ PRECIOUS METAL WASTES  -  SINGLE  OPTION

Introduction

This subsection describes the  techniques  that  are commonly used
for the removal/recovery of precious  metals  from waste streams
and presents silver removal performance data for Option 1 common
metals treatment systems.

Precious metal wastes are produced  in the  Metal  Finishing Category
by electroplating of precious  metals  and  subsequent finishing opera-
tions performed on the precious metals.   Included among the precious
metals are gold, silver, rhodium, palladium, platinum, osmium,
ruthenium, iridium, and indium.  Precious  metal  wastes can be
treated using the same treatment alternatives  as those described for
treatment of common metal wastes.   However,  due  to the intrinsic
value of precious metals, every effort should  be made to recover
them.  The treatment alternatives recommended  for precious metal
wastes are the recovery techniques:   evaporation, ion exchange
and electrolytic recovery.

EVAPORATION

Evaporation is used to recover precious metals by boiling off the
water portion of a precious metal solution.  This process is des-
cribed under the "Treatment of Common Metal  Wastes" heading.  Solu-
tions such as silver cyanide plating  baths are now being recovered
through the use of evaporation, the silver cyanide portion either
being returned to the process  tank  or held aside for subsequent
sale.  Figure 7-67 displays the system which was observed at Plant
ID 06090.  Plant personnel reported that  the recovery of silver
solutions paid back the capital cost  of the  evaporation equipment
after six months.

ION EXCHANGE

Ion exchange, which was described in  detail  under the "Treatment
of Common Metal Wastes" heading, is commonly used in the recovery
of precious metals, particularly gold.  This recovery process
can be used in an on-line or end-of~pipe  capacity.  Analyses of
samples taken before and after ion  exchange  at photoprocessing
plants* yielded the following  data:

                                    Silver  Concentration (mg/1)
     Plant                          Influent           Effluent

     6208                           2.0                0.14
     9061           Unit 1          0.74               0.04
                    Unit 2          0.60               0.10

Many plants have ion exchange  units hooked up  to rinses immediately

*From EPA Contract 68-01-4826


                                 VII-126

-------
         Parts Flow
  Surface
Preparation
Silver
Cyanide
Plating
   2 Stage
Countercurrent
    Rinse
                                  Concentrate
                                           Submerged
                                             Tube
                                           Evaporator
                                                         Condensate
^
to
                                          FIGURE  7-67
                      OBSERVED EVAPORATION  SYSTEM AT PLANT  ID 06090

-------
following precious metal plating operations  to  recover  the
metal and return the rinse water to the rinse tank.   If a com-
pany does precious metal work on a large  scale,  it may  segregate
its precious metal wastes and run them through  a series of  ion
exchangers prior to sending the water to  waste  treatment.  In any
case, the resins from the ion exchange units are saved  and  the
precious metal recovered, normally by burning off the resin.

ELECTROLYTIC RECOVERY

Although electrolytic recovery was covered under the  "Treatment
of Common Metal Wastes" heading, it is particularly applicable
to the recovery of precious metals.  This is because  the more
valuable precious metals offer a faster payback  on the  equipment
and energy costs.  As explained earlier,  equipment normally con-
sists of a dragout rinse located after the precious metal plating
step and an off line electrolytic recovery tank  with  pumps  and
piping connecting the two.  The dragout rinse solution  is recir-
culated between the tanks while the precious metal is plated  out
in the electrolytic recovery tank.  An electrolytic recovery  sys-
tem at a photoprocessing plant* was able  to  reduce silver con-
centrations from 476 mg/1 to 21 mg/1.

Silver Removal Performance Data

Included in the common metals Option 1 treatment system (precipi-
tation/sedimentation) data base are a total  of  21 sampled occur-
ences of silver.  The effluent concentration vs  raw waste plots for
these data are presented in Figure 7-68 for  properly  operated
Option 1 common metals treatment systems  and in  Figure  7-69 for the
entire Option 1 common metals data base.  Figure 7-70 presents the
data collection portfolio (DCP) data for  plants  that  incorporate
an Option 1 treatment system and discharge silver.  The pertinent
effluent performance data for silver are  summarized as  follows:

  Silver Performance Data - Option J^ Common  Metals Treatment  System

  Mean Silver Effluent Concentration             0.096   mg/1
  Variability Factors (from Table 7-9)           2.9(DM)-1.3(30-day)
  Daily Maximum Effluent Concentration           0.28    mg/1
  30-day Average Effluent Concentration          0.13    mg/1

The percentages of silver effluent concentrations that  are  less than
the daily maximum concentration limitation are  100% for the sampled
data base and 100% for the DCP data base.

*Plant ID 4550; EPA Contract 68-01-4826.
                                 VII-128

-------
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                                                          Silver  Raw Waste   (mg/1)
                                                                  FIGURE 7-69



                                           EFFLUENT CONCENTRATIONS vs RAW WASTE CONCENTRATIONS

                                                            OPTION 1  COMMON  METALS

-------
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   ,24-
  .20-
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                                                                              72
                                                                                        80
                                                   FIGURE  7-70


                              DCP DATA FOR EFFLUENT  SILVER CONCENTRATION  DISTRIBUTION

-------
TREATMENT OF COMPLEXED METAL WASTES -  SINGLE  OPTION

Introduction

This subsection describes the treatment  technique  recommended
for Options 1-3 and an alternative technique  which is  applica-
ble for the removal of complexed metal wastes.   The concentration
limitations for the common metals wastes  that remain after  the com-
plexes have been broken are identical  to  those  tabulated  in Table
7-6 for the Common Metals Subcategory.

Complexed metal wastes within the Metal  Finishing  Category  are a
product of electroless plating, immersion plating,  etching  and
printed circuit board manufacture.  The metals  in  these waste
streams are tied up or complexed by particular  chemicals  (complexing
agents) whose function is to prevent metals from falling  out of
solution.  This counteracts the technique employed  by  most  con-
ventional solids removal methods, so these treatment methods are
not always successful when used on complexed  metal  waste  streams.
Therefore, segregated treatment of these wastes  is  necessary.
The treatment method selected for the  treatment  of  complexed
metal wastes is high pH precipitation.

HIGH p_H PRECIPITATION/SEDIMENTATION

The wastewater treatment alternative of  hydroxide  precipitation
was described in great detail under the  heading  "Treatment  of
Common Metal Wastes".  High pH precipitation  is  a  type of chemical
precipitation which is particularly applicable  to  complexed metal
wastes.  The process involves adding chemicals  to  the  waste solu-
tion which bring about a drastic increase in  pH, breaking the com-
plex bond and precipitating the metals.

The treatment of solutions of complexed  copper  with calcium hy-
droxide, calcium oxide (lime), calcium chloride, or calcium sul-
fate at a pH of 11.6 - 12.5 will effectively  remove copper  from
the solution as a copper hydroxide.  Flocculation  of the  copper
hydroxide with an anionic polyelectrolyte accelerates  the settling
of sludge.  This process works well with both concentrated  baths
and dilute rinse baths.

The process equipment required for a high pH  system includes holding
and treatment tanks if the operation is  conducted  on a batch basis.
Also needed are pumps to transfer the  wastewater and a settling tank
to concentrate the precipitate.

Although results of lab tests have shown  that the  process is applic-
able to removing copper from complexed copper solutions with calcium
ions at a high pH, the effectiveness of  treatment  is determined by
                                VI1-132

-------
the structure  of  the complexing agent in the solution.  If  the nitro-
gen in the  complexing agent is completely substituted with  carboxyl
groups,  removal  of copper by the calcium ion is almost complete.
Complexing  agents containing no carboxyl group and only hydroxyl
groups show no copper removal.  The addition of small amounts of  sul-
fide ions or dithiocarbonates after the calcium ion treatment aids
in further  removal of copper.  Electroless nickel solutions were
also prepared  under laboratory conditions and the results show the
calcium treatment at a high pH to be effective.

The high pH precipitation process is presently in the laboratory
stage of development.

Alternative Treatment for Complexed Metals Waste

MEMBRANE FILTRATION

Membrane filtration is a treatment method whose primary use is as
an alternative to sedimentation for solids removal.  A description
of this treatment process, its application and performance, advan-
tages and  limitations, operational factors and demonstration status
are detailed in the "Treatment of Common Metal Wastes" segment.
This process has  also proven to be effective for treatment  of com-
plexed metal wastes.

Tests carried  out by a printed circuit board manufacturer show
that this  system  is also effective in the presence of strong che-
lating agents  such as EDTA, but continuous addition of the  chemical
reagent is  required.  Also, laboratory bench scale and pilot studies
have been  conducted on the following waste streams:

     A.   Tin  and lead waste containing thiourea-copper complexes
         were tested on a pilot unit for over 200 hours with no
          flux deterioration with tin, lead, and copper all less
          than 0.1 mg/1 in the product water.

     B.   Cupro-ammonia complex rinse from alkaline etching was
         treated in the pilot unit for 400 hours with no flux
         deterioration and with copper in the effluent less than
         0.1  mg/1.

         Based on this laboratory pilot study, a 1 gpm pilot test
         was  run in a printed circuit board manufacturing  facility.
         Over a  200 hour period, the flux was always in excess of
         1.1  gpm.  The effluent copper was consistently below
         0.5  mg/1 and usually at 0.1 mg/1, even with a varying
         concentration of copper in the feed.

     C.   Preliminary runs of electroless copper rinse waters have
         yielded product water in the range of 0.1 mg/1 copper.
                                    VII-133

-------
TREATMENT OF HEXAVALENT CHROMIUM WASTES  -  SINGLE OPTION

Introduction

This subsection describes the  treatment  system option for the
Hexavalent Chromium Waste Subcategory, presents effluent per-
formance, and discusses alternative  treatment  techniques.

Hexavalent chromium bearing wastewaters  are  produced  in the Metal
Finishing Category in several  ways:

          Chromium electroplating
          Chromate conversion  coatings
     -    Etching with chromic acid
     -    Metal finishing operations  carried out on chromium
            as a basis material

The selected treatment option  involves the reduction  of hexavalent
chromium to trivalent chromium.  The  reduced chromium can then  be
removed with a conventional precipitation-solids removal system.

CHEMICAL CHROMIUM REDUCTION

Description of the Process

Reduction is a chemical reaction in which  electrons are transferred
to the chemical being reduced  from the chemical initiating the
transfer (the reducing agent).  Sulfur dioxide,  sodium bisulfite,
sodium metabisulf i te , and ferrous sulfate  form strong reducing
agents in aqueous solution and are,  therefore,  useful in industrial
waste treatment facilities for the reduction of hexavalent chro-
mium to the trivalent form.  The reduction enables  the trivalent
chromium to be separated from  solution in  conjunction with other
metallic salts by alkaline precipitation.  Gaseous  sulfur dioxide
is a widely used reducing agent and provides a good example of
the chemical reduction process.  Reduction using other reagents is
chemically similar.  The reactions involved  may be  illustrated  as
follows :

     3 S02 + 3 H20       =     3 H2S03
The above reaction is favored by low pH.  A pH of  2  to  3  is  normal
for situations requiring complete reduction.  At pH  levels above
5, the reduction rate is slow.  Oxidizing agents such as  dissolved
oxygen and ferric iron interfere with  the reduction  process  by
consuming the reducing agent.
                               VII-134

-------
A typical treatment consists of two hours retention  in  an  equal-
ization tank followed by 45 minutes retention  in each of two  re-
action tanks connected in series.  Each reaction tank has  an  elec-
tronic recorder-controller device to control process conditions
with respect to pH and oxidation reduction potential  (ORP).   Gaseous
sulfur dioxide is metered to the reaction tanks to maintain  the ORP
within the range of 250 to 300 millivolts.  Sulfuric acid  is  added
to maintain a pH level of from 1.8 to 2.0.  Each of  the reaction
tanks is equipped with a propeller agitator designed to provide
approximately one turnover per minute.  Following reduction  of  the
hexavalent chromium, the waste is combined with other waste  streams
for final adjustment to an appropriate alkaline pH to remove  chromium
and other metals by precipitation and sedimentation.  Figure  7-71
shows a continuous chromium reduction system.

Application and Performance

Chromium reduction is used in metal finishing  for treating chromium
bearing waste streams, including chromium plating baths, chromating
baths and rinses.  The main application of chemical  reduction to  the
treatment of wastewater is in the reduction of hexavalent  chromium
to trivalent chromium.  Rinse waters and cooling tower  blowdown
are two major sources of chromium in waste streams.  A  study  of an
operational waste treatment facility chemically reducing hexavalent
chromium has shown that a 99.7% reduction efficiency is easily
achieved.  Final concentrations of 0.05 mg/1 are readily attained,
and concentrations down to 0.01 mg/1 are documented  in  the litera-
ture.

Presented below are sampling results at metal  finishing plants
30050 and 30074.

                           30050       (mg/1)      30074

                    Before      After        Before        After
Parameter           Reduction   Reduction    Reduction     Reduction

Chromium, Hex.        0.8         .005         109.          .005

Advantages and Limitations

The major advantage of chemical reduction of hexavalent chromium
is that it is a fully proven technology based  on years  of  exper-
ience.  Operation at ambient conditions results in minimal energy
consumption, and the process, especially when  using  sulfur dioxide,
is well suited to automatic control.  Furthermore, the  equipment
is readily obtainable from many suppliers, and operation  is
straight forward.
                               VII-135

-------
                                                   SULFUR 1C
                                                      ACID
SULFUR
DIOXIDE
CO
ON
1
	 r* 	 i
PH CONTnOULERl [
LJ -j
i
i
RAW WASTE |
(HEXAVALENT CHROMIUM)
|
»_jjl 	 I'll f~ \
I
1
. J
1

o


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; 	 -i
	 I JOHP CONTROLLER
1
1
1
1
, 1
— M
J
D


(TRIVALENT CHROMIUM)
                                                     REACTION TANK
                                                    FIGURE 7-71
                             HEXAVALENT CHROMIUM REDUCTION  WITH SULFUR  DIOXIDE

-------
One limitation of chemical reduction of hexavalent chromium  is  that
for high concentrations of chromium, the cost of treatment chemicals
may be correspondingly high.  When this situation occurs, other
treatment techniques are likely to be more economical.  Chemical
interference by oxidizing agents is possible in the treatment of
mixed wastes, and the treatment itself may introduce pollutants  if
not properly controlled.  Storage and handling of sulfur dioxide  is
somewhat hazardous.

Operational Factors

Reliability;  Maintenance consists of periodic removal of sludge,
the frequency of which is a function of the input concentrations
of detrimental constituents.

Solid Waste Aspects;  Pretreatment to eliminate substances which
will interfere with the process may often be necessary.  This
process produces trivalent chromium which can be controlled  by
further treatment.  There may, however, be small amounts of  sludge
collected due to minor shifts in the solubility of the contaminants.
This sludge can be processed by the main sludge treatment equipment.

Demonstration Status

The reduction of chromium waste by sulfur dioxide or sodium  bisul-
fite is a classic process and is used by numerous plants employing
chromium compounds in metal finishing and non-contact cooling
operations.

Chemical chromium reduction is used in 343 plants in the present
data base and these are identified - in Table 7-22.

Hexavalent Chromium Treatment System Performance

The performance data base for the Hexavalent Chromium Subcategory
is presented in Figure 7-72 for the Metal Finishing Category.
These data are for plants that employ the chemical reduction of
chromium.  This performance data is summarized as follows:

          Hexavalent Chromium Performance Data

  Mean Effluent Chromium                   0.032  mg/1
  Variability Factors (from Table 7-5)     5.2(DM)-1.5(20-day)
  Daily Maximum Effluent Concentration     0.166  mg/1
  30-day Average Concentration             0.048  mg/1

Figure 7-73 presents the data collection portfolio (DCP) effluent
concentration distribution for hexavalent chromium and the daily
maximum concentration is overlayed for data comparison.  The
percentages of hexavalent chromium effluent concentrations that
are less than the daily maximum concentration limitation are
100% for the sampled data base and 64% for the DCP data base.
                               VII-137

-------
                             Table 7-22
Metal Finishing Plants Employing  Chemical Chromium Reduction
01007
01067
01068
02037
02038
03043
04033
04069
04100
04114
04146
04151
04175
04199
04214
04216
04219
04221
04222
04261
04276
04277
04281
20077
20078
20079
20080
20081
20082
20083
20084
20085
20086
20087
20094
20104
20109
20112
20115
20116
20120
20121
20123
20136
20143
20145
20149
20150
04282
04284
04690
04719
05033
05035
05050
06002
06006
06035
06050
06051
06052
06053
06062
06072
06073
06074
06076
06077
06078
06079
06083
20152
20157
20158
20160
20172
20241
21003
21051
21059
21062
21066
21074
21078
22028
22031
22735
23039
23048
23056
23059
23061
23066
23070
23076
23337
06084
06085
06086
06087
06088
06090
06091
06094
06096
06112
06113
06115
06117
06118
06124
06129
06148
06156
06358
06360
06381
06679
06371
25001
25030
25031
25033
25034
25037
27042
28081
28082
28094
28096
28109
30009
30011
30050
30054
30058
30064
30074
30087
30090
30096
30097
30101
30111
06960
07001
08004
08008
08061
08072
08074
08081
09025
09040
09041
09046
09061
11008
11065
11096
11113
11121
11127
11129
11139
11140
11156
30121
30127
30148
30153
30155
30157
30162
30507
30967
31020
31021
31022
31035
31037
31040
31054
31050
31069
31071
33024
33033
33043
33070
33071
33073
11165
11173
11174
11184
11477
11704
12005
12010
12014
12065
12068
12071
12074
12075
12078
12080
12081
12084
12087
12090
12100
12102
12105
33074
33107
33112
33113
33116
33126
33129
33133
33137
33150
33172
33183
33184
33195
33197
33199
33287
33293
33852
34037
34039
34041
34042
34050
35040
13031
13033
13034
13039
13040
14060
14062
15010
15036
15042
15044
15047
15048
15057
15070
15193
15194
16032
16033
16035
16544
17030
17032
35061
36001
36036
36040
36041
36082
36083
36090
36091
36102
36112
36113
36130
36149
36154
36155
36157
36161
36162
36166
36177
36179
36937
37063
38031
17033
17050
18050
18532
18538
19051
19063
19066
19067
19068
19084
19090
19091
19104
20001
20005
20010
20017
20064
20069
20070
20073
20076
38035
38051
38052
38222
38223
40047
40048
40061
40062
41092
41869
43003
44037
44040
44042
44044
44050
44062
44148
44150
45035
45041
45045
46031
47005
                                                                       47025
                                                                       47059
                                                                       47068
                                                                       47074
                                                                       47412
                                                                       62032
                                                                       62052
                                    VII-138

-------
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                       .1
1                              10


Hexavalent Chromium Raw Waste  (mg/1)
100
                                                               FIGURE 7-72
                             EFFLUENT HEXAVALENT CHROMIUM CONCENTRATIONS  vs RAW WASTE CONCENTRATIONS

-------
      1.4
      1.2
      1.0
    -P
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    D
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                               m
Daily Maximum
                   m a
                                   Q
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                    20
     40
60
80
100
                         Percentile Distribution
                             FIGURE  7-73


DCP DATA FOR EFFLUENT HEXAVALENT  CHROMIUM CONCENTRATION DISTRIBUTION
                                VI1-140

-------
ELECTROCHEMICAL CHROMIUM REDUCTION

This process has been developed to aid the removal of  chromium
from metal finishing and cooling tower blowdown wastewaters.
It involves an electrochemical reaction in which consumable  iron
electrodes in the presence of an electrical current generate
ferrous ions which react with chromate ions in solution.  The
reaction produces chromic hydroxides and ferric hydroxides that
can be removed in a settling pond or clarifier without  the need
for further chemical addition.  The process has also been shown
effective in removing zinc and other heavy metals.  The metallic
hydroxides formed are gelatinous and highly adsorptive.  They can
therefore coprecipitate other species which might be present in a
wastewater solution.

In addition to the electrochemical unit, the only equipment  re-
quired is a pump and a clarifier or pond for settling.  As long
as the pH of the entering waste stream is between 7.0  and 8.0,
no pH adjustment is necessary.

Application and Performance

Although the process was developed for removal of chromium and
zinc from cooling tower discharge, electrochemical chromium  reduc-
tion can also be applied to the treatment of metal finishing waste-
waters such as chromating baths and rinses.  Coil coating and
porcelain enameling plants are other potential applications.
According to manufacturers, the electrochemical reduction
process performs best on low concentration, high volume wastewater
streams.  Conventional chemical reduction is probably more econom-
ical in treating more concentrated effluents.

The process is capable of removing hexavalent chromium  from  waste-
water to less than 0.05 mg/1 with input chromium concentrations
up to at least 20 mg/1.  Performance for one plant is  as follows:

     Pollutant           Influent       Effluent

     Hexavalent Chromium   10 mg/1      0.05 mg/1
     Zinc                   3           0.1

Laboratory tests have also shown that the process is capable of
removing metals other than chromium to the following levels  (in-
let concentrations not available):

          Metal                    Concentration (mg/1)

          Zinc                          0.1
          Nickel                        2.1
          Copper                        0.2
          Silver                        0.5
          Tin                           <5
                             VII-141

-------
No retention time is required since  the  reaction  is  instantaneous
at pH values between 7.0 and 8.0, but  subsequent  sedimentation
is needed to remove the precipitate  in the  reaction.

Advantages and Limitations

An advantage of the electrochemical  chromium  reduction process is
that no pH adjustment chemicals are  required  with incoming pH
values between 7 and 8.  No retention  time  is required,  and the
process is continuous and automatic.   However,  it is  not efficient
for effluents with high chromium concentrations,  and  species
which consume hydroxide ions interfere with the precipitation of
the ferric and ferrous hydroxides.

Operational Factors

Reliability;  Very good, so long as  interfering species  are removed
prior to reaching the process tank and the  recommended power require-
ments are properly met.

Maintainability;  The system normally  requires  about  thirty minutes
of operator time per day.  Since the iron electrodes  are consumable
they need to be replaced periodically.   Sedimentation is part of the
process and there is consequently a  demand  for  sludge processing and
removal.

Solid Waste Aspects;  The precipitation  of  ferric and chromic hy-
droxides generates waste sludge which  must  eventually be dewatered
and properly disposed.  No appreciable amounts  of sludge are al-
lowed to settle in the actual electrochemical process tank.

Demonstration Status

There are more than 50 electrochemical reduction  systems in opera-
tion in a variety of industries, mostly  in  organic and inorganic
chemicals plants.  Five are presently  in service  at plants in the
metal finishing industry.  The process has  potential  for applica-
tions in the photographic industry since it has been  shown to
successfully remove silver from wastewaters.  Chromium reduction
is used in 2 plants in the present data  base:   34051  and 42030.


Alternative Hexavalent Chromium Treatment Techniques

The following treatments are recovery  techniques  which can also
be applied to waste streams containing hexavalent chromium.   They
include electrochemical chromium regeneration,  electrodialysis,
evaporation and ion exchange.
                                VTI-142

-------
ELECTROCHEMICAL CHROMIUM REGENERATION

Chromic acid baths must be continually discarded  and  replenished
to prevent buildup of trivalent chromium.  An  electrochemical  sys-
tem employing a lead anode and nickel cathode  has been  developed
to recover chromium by converting the trivalent form  to the  hexa-
valent form. In this process, trivalent chromium  is electro-oxidized
to hexavalent chromium at the lead anode while hydrogen is released
at the nickel cathode.  This process is similar to the  electro-
dialytic chromium oxidation process, but no membrane  is used to
separate concentrate from dilute solution.  The reaction is  carried
out at 68°C, a cell voltage of 4.5 volts, and  an  anode-to-cathode
area ratio of 30:1.  The same process can also be used  to recover
chromium from chromic oxide sludges precipitated  by conventional
chemical chromium waste treatment.  The sludges are dissolved  in
200 g/1 chromic acid and electro-oxidized under slightly different
operating conditions than those previously described.

Application and Performance

Electrochemical chromium regeneration can be used in  metal finishing
to prolong the life of chromium plating and chromating  baths.  Chrom-
ic acid baths are used for electroplating, anodizing, etching, chroma-
ting and sealing.  The electro-oxidation process  has  been commercially
applied to regeneration of a plastic etchant.  In this  particular
installation, chromic acid dragged out of the  etching bath into  the
first stage of a countercurrent rinse is concentrated by evaporation
and returned to the etching bath.  This closed loop system tends
to cause a rapid buildup of trivalent chromium.   However, when the
etchant is recirculated through an electrochemical regeneration
unit, the trivalent chromium is oxidized to the hexavalent form.
The current efficiency for this process is 80 percent at concentra-
tions above 5 g/1.  If a trivalent chromium concentration of less
than 5 g/1 were treated, research has shown that  the  current effi-
ciency would drop to 49 percent.  The process  has also  been  applied
to regeneration of a chromic acid sealing bath in the coil coating
industry.

Advantages and Limitations

Some advantages of the electrochemical chromium regeneration pro-
cess are its relatively low energy consumption, its operation  at
normal bath temperature, eliminating need for heating or cooling,
its ability for recovering and reusing valuable process chemicals,
and elimination of sludges generated by conventional  chromium
treatment processes.  Some limitations of chromium electro-
oxidation are low current efficiencies for baths  with less than
5.0 g/1 trivalent chromium, need for control of impurities which
can interfere with the process, and dependence on electrical
energy for oxidation to take place.
                               VII-143

-------
Operational Factors

Reliability;  Close control of operation  conditions  is essential.
Long terra cell reliability has not been determined.

Maintainability:  Requires periodic replacement  of electrodes and
adequate ventilation.

Solid Waste Aspects;  Does not create solid wastes.   Helps to
minimize sludge generation by replacing another  treatment sys-
tem which produces large volumes of solid wastes in  comparison.

Demonstration Status

One automobile plant  (Plant ID 12078) is  using the system exper-
imentally to regenerate a chromic acid etching solution.   In addi-
tion, one coil coater (Plant ID 01054) is using  it on a full scale
basis to regenerate a chromic acid sealing bath.  Standard equip-
ment is not commercially available.

ADVANCED ELECTRODIALYSIS

This particular electrodialysis system is used to oxidize chromium
in chromic acid from a trivalent form to  a hexavalent form.   Its
design uses a circular, permeable anode,  separated from the
cathode by perfluorosulfonic membrane.  The anode material is a
specially designed lead alloy.  The cathode is made  from  Hastelloy
C tubing, which is a nickel alloy.  The cathode  is located in the
center of the circular, permeable anode and has  a catholyte  (10
percent sulfuric acid) which is circulating through  it and sur-
rounds the cathode.  This solution is used as a  transfer  solution.
Figure 7-74 shows the physical construction of this  circular
electrodialysis cell.

The etchant is pumped in at the bottom of the unit through the anode
so that it remains in the chamber between the anode  and the  perfluor-
osulfonic membrane.  Chromium in the trivalent form  is contained in
the etchant and, when a current is passed through this etchant solu-
tion, electrons are stripped from the trivalent  chromium  causing
oxidation of the trivalent chromium to hexavalent chromium.   The
newly stripped electrons migrate through  the perfluorosulfonic
membrane into the catholyte solution.  Converted hexavalent  chro-
mium is pumped back into the chromium etch tank  for  reuse, while
at the same time the catholytic solution  is being recirculated.
The reaction which occurs at the anode is as follows:

     Cr+3 + 12 H20 - 3e- = Cr04"2 + 8H30+1 + 6e-

This reaction is continually taking place as both the etchant and
the catholyte are circulated through the  cell.
                                VII-144

-------
                                                                CATHOLYTIC

SPENT CHROMIC
ACID
                                       CATHODE-
ACID
ENERATED
OMIC ACID ^
ANODE -
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                                                                                   CATHOLYTE
                                                                                    STORAGE
                     TOP VIEW
                      SIDE  VIEW
                                        FIGURE 7-74

                                  ELECTROLYTIC RECOVERY

-------
Application of Advanced  Electrodialysis

Electrodialysis  of  chromium,  oxidizing  trivalent chromium to hexa-
valent chromium,  is  not  a  widely  practiced method of waste treat-
ment as yet.  It  is,  however,  a very  efficient method for waste
treatment of  chromium, and it  is  used at one company visited
(ID 20064).   This electrodialysis cell  closes the loop on chro-
mium so that  there  is no need  to  reduce  hexavalent chromium.  The
only application, current  or  predicted,  for this electrodialysis
cell system is the  oxidation  of chromium wastes.

Performance of Advanced  Electrodialysis

The electrical efficiency  of  the  unit varies with the concentration
of both hexavalent  chromium and trivalent chromium.   The electro-
chemical efficiency  of the unit is  generally between 50 to 90 per-
cent, depending on  the concentrations.   This corresponds to an
energy consumption  of 8  to 16  kwh/kg  of  chromic acid from reduced
chromium.  The metal  removal efficiency  of the electrodialysis unit
is 90 percent for 8  mg/1 of trivalent chromium and 95 percent for
12 mg/1.

EVAPORATION

Evaporation, which  is explained in  detail in the "Treatment of
Common Metal Wastes" has found applicability in the  treatment of
chromium bearing wastes, especially the  rinse waters after chromium
plating.  The rinse  waters following  the  finishing operation (nor-
mally a countercurrent rinse of at  least  three stages)  are sent to
an evaporator.  Here the chromium bearing solution is broken down
into water and process solution (predominantly chromic  acid).  The
water is returned to the last  (cleanest)  stage of the countercurrent
rinse and the process solution may  be returned to the process tank
or put aside for sale to a scavenger.  Plant 33065 has  a similar
arrangement on their chromium  plating line.   The data presented
below represent the  raw waste  stream  going to evaporation and
the countercurrent stream  being returned  to  plating.

                     Input  To
Parameter           Evaporator      (mg/1)     Concentrate

Chromium,  Total      5060                      27,500
Chromium,  Hex       4770                      16,700
TSS                  <.l                       400
PH                  1.6                       1.4
                                VII-146

-------
ION EXCHANGE

Ion exchange  is another possible method for recovering  and  regener-
ating chromic acid solution.  As explained under  the  "Treatment of
Common Metal  Wastes" segment, anions such as chromates  or dichro-
mates can be  removed from rinse waters with an anion  exchange  resin.
In order to regenerate the resin, caustic is pumped through the
anion exchanger, carrying out sodium dichromate.  The sodium dichro-
mate stream is passed through a cation exchanger, converting the
sodium dichromate to chromic acid.  After some means  of concentra-
tion such as  evaporation, the chromic acid can be returned  to  the
process bath.  Plant 33065 uses a cation exchanger in such  a manner.
The sampling  results of the influent and effluent stream of the ion
exchange unit are shown below.

                              Input To            Ion Exchange
Parameter                     Ion Exchange            Effluent

Chromium, Total               4610                      5060
Chromium, Hex.                2230                      4770
TSS                           67                        <.01
pH                            1.8                       1.6
                             VII-147

-------
TREATMENT OF CYANIDE WASTES - SINGLE OPTION

Introduction

This subsection describes the technique  recommended for cyanide
treatment, discusses the mean cyanide  concentrations found, iden-
tifies the recommended daily maximum and 30-day average concen-
trations for cyanide and presents  alternative  treatments for the
destruction of cyanide.

The following paragraphs describe  the  chlorine oxidation technique
recommended for the treatment of wastes  in the Cyanide Subcategory.

OXIDATION BY CHLORINE

Cyanides are introduced as metal salts for plating  and conversion
coating or are active components in plating  and cleaning baths.
Cyanide is generally destroyed by  oxidation.

Chlorine is used primarily as an oxidizing agent in industrial
waste treatment to destroy cyanide.  Chlorine  can be used in
the elemental or hypochlorite form.  This classic procedure can
be illustrated by the following two step chemical reaction:

     1.   C12 + NaCN + 2NaOH = NaCNO + 2NaCl + H2O

     2.   3C12 + 6NaOH + 2NaCNO =  2NaHC03 +  N2 + 6NaCl + 2H20

The reaction presented as equation(2)  for the  oxidation of cyanate
is the final step in the oxidation of  cyanide.  A complete system
for the alkaline chlorination of cyanide is  shown in Figure 7-75.

The cyanide waste flow is treated  by the alkaline chlorination
process for oxidation of cyanides  to carbon  dioxide and nitrogen.
The equipment often consists of an equalization tank followed by
two reaction tanks, although the reaction can  be carried out in a
single tank.  Each tank has an electronic recorder-controller to
maintain required conditions with  respect to pH and oxidation-
reduction potential (ORP).  In the first reaction tank, conditions
are adjusted to oxidize cyanides to cyanates.   To effect the reac-
tion, chlorine is metered to the reaction tank as required to main-
tain the ORP in the range of 350 to 400  millivolts, and 50% aqueous
caustic soda is added to maintain  a pH range of 9.5 to 10.  In
the second reaction tank, conditions are maintained to oxidize
cyanate to carbon dioxide and nitrogen.   The desirable ORP and
pH for this reaction are 600 millivolts  and  a  pH of 8.0.  Each of
the reaction tanks is equipped with a  propeller agitator designed
to provide approximately one turnover  per minute.  Treatment by
the batch process is accomplished  by using two tanks, one for col-
lection of waste over a specified  time period, and  one tank for
the treatment of an accumulated batch.  If dumps of concentrated
wastes are frequent, another tank  may  be required to equalize the
flow to the treatment tank.  When  the  holding  tank  is full, the


                              VTI-148

-------
VD
          HAW  WASTE
                  CAUSTIC
                   SODA
CONTROLLER
gn:
              r^~~«-L^/-«
                           n
                           oo
                    HEACTION TANK
                                        WATER
                                       CONTAINING
                                                CYANATE
                                       CHUOR INt
                                             — v
                                              \
                                              CHI-OR INATOR
                                                                        CAUSTIC
                                                                         SODA
                                                            00
                                                                           D,  (—1
                                                                           -- 1  1
                                                                          PH
                                                                       CONTROUUER
                                                                   REACTION TANK
                                                                            . TREATED
                                                                             WASTE
                                            FIGURE 7-75
                           TREATMENT OF CYANIDE WASTE BY ALKALINE CHLORINATION

-------
liquid is transferred  to  the  reaction  tank  for treatment.  After
treatment, the supernatant  is discharged  and  the sludges are col-
lected for removal and ultimate disposal.

Application and Performance

The oxidation of cyanide  waste by  chlorine  is a classic process and
is found in most plants using cyanide.  This  process is capable of
achieving efficiencies of 99  percent or greater and  effluent levels
that are nondetectable.   Chlorine  has  also  been used to oxidize
phenols, but use of chlorine  dioxide for  this purpose is much pre-
ferred because formation  of toxic  chlorophenols is avoided.

Advantages and Limitations

Some advantages of chlorine oxidation  for handling process effluents
are operation at ambient  temperature,  suitability for automatic
control, and low cost.  Some  disadvantages  of chlorine oxidation
for treatment of process  effluents are that toxic, volatile inter-
mediate reaction products must be  controlled  by careful pH adjust-
ment, chemical interference is possible in  the treatment of mixed
wastes, and a potentially hazardous situation exists when chlorine
gas is stored and handled.

Operational Factors

Re1iabi1ity;  High, assuming  proper monitoring and control, and
proper pretreatment to control interfering  substances.

Maintainability:  Maintenance consists of periodic removal of
sludge and recalibration  of instruments.

Solid Waste Aspects;  There is no  solid waste problem associated
with chlorine oxidation.

Demonstration Status

The oxidation of cyanide wastes by chlorine is a widely used pro-
cess in plants using cyanide  in cleaning  and  plating baths.  There
has been recent attention to  developing chlorine dioxide genera-
tors and bromine chloride generators.  A problem that has
been encountered is that  the  generators produce not  only the
bromine chloride and chlorine dioxide  gas,  but chlorine gas is
also formed simultaneously.   Both  of these  gases are extremely
unstable, corrosive, and have low  vapor pressure,  which results
in handling difficulties.  These generators are in the develop-
ment stages and as advances are made in their design, they may
become competitive with chlorine.
                                 VI1-150

-------
Oxidation by chlorine is used in 201 plants  in  the present
data base and these are identified in Table  7-23A.

                         Table 7-23A
     Metal Finishing Plants Employing Cyanide Oxidation
01007
01068
02033
02037
02040
03042
04045
04076
04114
04178
04199
04124
04227
04236
04263
04277
04279
04281
05021
05029
05033
06002
06006
06037











06050 06120
06051 06122
06052 06124
06053 06129
06002 06141
06072 06146
06073 06147
06075 06152
06079 06358
06078 06360
06079 06381
06081 06679
06084 08004
06085 08008
06087 08074
06089 09026
06090 09060
06094 10020
06101 11096
06107 11098
06111 11103
06113 11118
06115 11174
06119 11177
34042
35061
35963
36036
36040
36041
36082
36083
36084
36090
36091
11184
12005
12065
12078
12087
12709
13033
13034
13039
13040
15042
15045
15047
15048
15070
15193
16033
16035
18050
18055
18534
19050
19051
19063
36102
36112
36113
36151
36154
36156
36623
37042
38031
38038
38051
19069 21003
19084 21062
19090 21066
19099 21074
19102 21078
19104 22028
20001 22656
20005 23039
20017 23059
20073 23061
20077 23074
20078 23076
20079 23337
20080 25001
20081 25030
20082 25031
20084 27044
20086 27046
20087 28082
20158 28105
20162 30011
20172 30022
20243 30090
20708 30096
38223
40037
40047
41116
42830
43052
44037
44040
45035
47005
47025
30097
30109
30111
30162
30967
31021
31037
31040
31047
31070
33024
33043
33065
33070
33071
33073
33113
33120
33137
33146
33184
33187
33275
34041











Cyanide Oxidation System Performance

Tables 7-23B and 7-23C list the concentration  levels  of  total
cyanide (CNT) and cyanide amenable to chlorination  (CNA)  found
in the cyanide waste streams of visited plants after  oxidation,
Each table has the following four columns:
                            VII-151

-------
                        TABLE 7-23B
             DATA USED TOR TOTAL CYANIDE PERFORMANCE
               Total Cyanide
 Plant ID      Effluent Concentration
                       (mg/D

 21051                 0.0
 21051                 0.0
 21051                 0.0
 38051                 0,0
 20080                 .005
 20080                 .005
 20080                 ,005
 05021                 .005
 05021                 .005
 06075                 .005
 20079                 .005
 06075                 .005
 20078                 .005
 20078                 .005
 20080                 .005
 20079                 .005
 20079                 .005
 19050                 ,005
 20078                 .005
 20077                 .005
 20078                 .005
 20079                 e005
 36623                 .01
 15070                 ,02
 05021                 .007
 06075                 .014
 20082                  .034
 20078                 .01
 33073                  .013
 09026                  .03
 09026                  002
 06084                  .027
 36623                  .02
 15070                  .03
 20079                  .02
 12065                  .014
 36623                  .033
 33024                  .04
 09026                  .08
 20078                  .04
 20081                  ,023
33070                  .042
20080                  1
20080                  .111
31021                  .16
Dilution Factor
    1.0
    1.0
    1.0
   19.9
    4.5
    4.5
    4.5
    4.8
    4.8
    4.8
    4.8
    5.0
    5.6
    5.8
    5.8
    6.0
    6.2
    6.2
    7.0
    7.1
    7.4
    7.9
    4.2
    2.5
    8.0
    4.8
    2.0
    6.9
    5.5
    2.4
    3.8
    2.9
    4.8
    3.4
    5.5
  10.0
    5.1
    5.0
    2.6
    6.6
  14.4
    8.4
    4.1
    4.0
    2.9
Adjusted Total Cyanide
Concentration
       (mg/1)

    0.0
    0.0
    0.0
    0.0
     .023
     .023
     .023
     .024
     .024
     .024
     .024
     .025
     .028
     .029
     .029
     .03
     .031
     .031
     .035
     .036
     .037
     .039
     .042
     .05
     .056
     .067
     .068
     .069
     .071
     .072
     .076
     .078
     .096
     .102
     .110
     .14
     .167
     .2
     .208
     .266
     .331
     .353
     .41
     .444
     .472
                                    VII-152A

-------
                       TABLE 7-23B GONT'D
               DATA USED FDR TOTAL CYANIDE PERFORMANCE
              Total Cyanide
Plant ID       Effluent Concentration
                     (mg/1)
Dilution Factor
Adjusted Total Cyanide
Concentration
       (mg/D
31021
33070
20081
33073
06381
15070
06089
33070
20081
31021
06089
20082
33073
20082
06381
06084
20082
36041
20086
06037
06037
36041
06085
06085
20086
20082
20080
36041
06381
04045
20082
06089
04045
06085
06084
06090
20077
04045
20081
20077
20077
20081
20077
20077
.16
.065
.035
,129
.089
.29
.285
.101
.068
.35
.428
.635
.254
.722
.25
.435
.945
.25
.73
.53
.591
.4
.96
.92
1.13
3.09
1.23
.6
.981
6.4
3.31
2.42
8.7
1.8
2.8
2.81
1.5
15.2
.911
2.5
3.0
1.16
2.5
2.4
3.2
8.4
17.7
5.1
8.7
2.8
2.9
8.4
15.9
3.1
3.0
2.1
5.5
2.0
6.3
4.3
2.0
11.5
4.5
6.3
6.3
10.1
4.8
5.4
4.5
1.8
4.6
10.4
6.5
1.0
2.1
3.5
1.0
5.0
3.6
4.3
9.7
1.0
17.6
6.5
5.9
16.3
7.8
9.7
.506
.546
.618
.66
.773
.818
.835
.848
1.08
1.1
1.28
1.34
1.39
1.47
1.58
1.86
1.88
2.87
3.28
3.37
3.75
4.04
4.61
4.95
5.08
5.63
5.69
6.24
6.38
6.4
6.85
8.47
8.7
9.0
10.2
12ol
14.6
15.2
16.0
16.2
17.7
19.0
19.5
23.3
                                   VII-152B

-------
                        TABLE 7-23B CONT'D
                DATA USED FOR TOTAL CYANIDE PERFORMANCE
               Total Cyanide
Plant ID       Effluent Concentration
                      (mg/1)

20086               5.25
11103              10.0
02033              10.0
11103               9.37
06090               6.73
06090              10.8
20081               3.82
21066              16.38
06037              12.6
20079              21.0
21066              12.15
21066              20.65
Dilution Factor
     4.5
     2.4
     2.6
     3.0
     4.3
     4.3
    15.6
     4.7
     6.4
     5.0
    10.2
     7.4
Adjusted Total Cyanide
Concentration
       (mg/1)

     23.6
     24.0
     26.0
     28.1
     28.7
     46.1
     59.6
     76.9
     80.6
    105.0
    123.9
    152.8
                                    VII-152C

-------
                        TABLE 7-23C
        DATA USED FOR CALCULATION OF CNA PERFORMANCE
               Amenable Cyanide
Plant ID       Effluent Concentration
                      (mg/1)

12065                  0.0
21051                  0.0
21051                  0.0
21051                  0.0
38051                  0.0
15070                   .005
15070                   .005
09026                   .005
36623                   .005
20080                   .005
20080                   .005
20080                   .005
22086                   .005
05021                   .005
05021                   .005
06075                   .005
20079                   .005
09026                   .01
36623                   .005
06075                   .005
20079                   .005
36623                   .005
20078                   .005
20079                   .005
20078                   .005
20080                   .005
20079                   .005
20079                   .005
19050                   .005
20078                   .005
20078                   .005
20077                   .005
20078                   .005
20079                   .005
05021                   .005
33073                   .008
20077                   .005
20078                   .01
20082                   .034
15070                   .02
20081                   .005
20081                   .005
Dilution Factor
     10.1
               Adjusted Amenable
               Cyanide Concentration
                       (mg/1)
      1.0
     19.9
      2.5
      2.8
      3.8
      4.3
      4.5
      4.5
      4.5
      4.5
      4.8
      4.8
      4.8
      4.8
      2.4
      4.9
      5.
      5.
   0
   0
 5.1
 5.6
 5.6
 5.7
 5.8
 6.1
 6.2
 6.2
 6.9
 7.0
 7.1
 7.4
 7.9
 8.0
 5.1
 9.7
 6.6
 2.0
 3.4
14.4
15.9
0.0
0.0
0.0
0.0
0.0
 .012 *
 .014 *
 .019 *
 .021 *
 .023 *
 .023 *
 .023 *
 .023
 .024 *
 .024 *
 .024 *
 .024 *
 .024 *
 .024 *
 .025 *
 .025 *
 .025
 .028 *
 .028 *
 .029 *
 .029 *
 .03  *
 .031 *
 .031 *
 .034 *
 .035 *
 .036 *
 .037 *
 .039 *
 .04  *
 .041 *
 .049
 .066 *
 .068 *
 .068 *
 .072 *
 .079 *
   Denotes data used for calculation of performance for cyanide
   amenable to chlorination.  These values correspond to values
   used for CN  performance.
                                    VII-152D

-------
          TABLE 7-2 3C CON'T
DATA USED FOR CALCULATION OF CM
                                         PERFORMANCE
               Amenable Cyanide
Plant  ID       Effluent Concentration
                       (mg/D

20082                   .056
33073                   .027
31021                   .05
09026                   .06
31021                   .05
31021                   .05
33024                   .04
04045                   .25
20081                   .017
06085                   .06
20080                   .104
06089                   .163
06381                   .096
20077                   .1
06381                   .089
06037                   .122
06089                   .285
04045                  1.0
36041                   .1
06090                   .24
36041                   .1
20082                   .625
20081                   .075
20086                   .36
20082                   .945
04045                  2.2
20082                  1.08
06037                   .408
06085                   .56
06089                  1.14
36041                   .4
06381                   .751
06085                  1.08
20082                  3.0
20081                   .348
11103                  2.91
06084                  1.97
20077                   .78
20081                   .49
11103                  3.37
02033                  4.2
06090                  2.88
                                Dilution Factor
                                     2.0
                                     5.5
                                     3.0
                                     2.6
                                     3.1
                                     3.1
                                     5.0
                                     1.0
                                    17.7
                                     5.4
                                     4.0
                                     2.9
                                     6.3
                                     6.5
                                     8.7
                                     6.4
                                     3.
                                     1,
                                    10.1
                                     4.3
                                    11.5
                                     2.1
                                    17.6
                                     4.5
2.
1.
                                      .0
                                      .0
                                     2.1
                                     6.4
                                     4.8
                                     3.5
                                    10.4
                                     6.5
                                     5.0
                                     1.8
                                    16.3
                                     2.4
                                     3.6
                                     9.7
                                    15.6
                                     3.0
                                     2.6
                                     4.3
Adjusted Amenable
Cyanide Concentration
       (mg/1)

     .112 *
     .147 *
     .15  *
     .156 *
     .158 *
     .158 *
     .2   *
     .25
     .3   *
     .323
     .416 *
     .478 *
     .609 *
     .65
     .773 *
     .775
     .855 *
    1.0
    1.01
    1.02
    1.15
    1.32 *
    1.32
    1.62
    1.88 *
    2.2
    2.23
    2.59
    2.69
    3.99
    4.16
    4.88
    5.4
    5.4
    5.68
    6.98
    7.19
    7.58
    7.64
   10.0
   11.1
   12.3
   Denotes data used for calculation of performance for cyanide
   amenable to chlorination.   These values correspond to values
   used for CN  performance.
                                     VII-152E

-------
                 TABLE  7-23C  OON'T
        DATA USED FOR CALCULATION OF  CN  PERFORMANCE
                                       £\

              Amenable  Cyanide                             Adjusted  Amenable
Plant ID      Effluent  Concentration   Dilution  Factor    Cyanide Concentration
                       (mg/1)                                       (rog/1)

20077                   2.1                   7.8                    16.4
20077                   3.0                   5.9                    17.7
06090                   5.27                  4.3                    22.5
20086                   5.25                  4.5                    23.6
21066                   8.83                  4.7                    41.5
21066                   6.57                 10.2                    66.9
06037                 11.6                   6.4                    73.7
21066                 11.75                  7.4                    86.9
                                   VII-152F

-------
ID Number - The identification number of  the  visited  plant.
Duplicate numbers indicate different sampling  days  at the
same plant.

Effluent Concentration - The measured concentration of the final
effluent after treatment.  At this point,  cyanide wastes  are
mixed with other wastewaters.

Dilution Factor - This number represents  the  amount of dilution
ofthe cyanide raw waste stream by other  raw  waste  streams and
is determined by dividing the total effluent  stream flow  by  the
cyanide stream flow.

Adjusted Cyanide Effluent Concentration -  These  concentrations
are calculated by multiplying the effluent cyanide  concentra-
tions by the dilution factor applicable in each  individual case.

The adjusted effluent cyanide concentrations  were averaged to
reflect the conditions in a typical cyanide waste stream  after
oxidation and before any dilution has taken place.  In calcu-
lating the mean adjusted effluent cyanide  concentrations,  which
are presented below, end of pipe concentrations  of  total  cyanide
greater than 2 mg/1 were eliminated.  Figure  7-76 shows total
cyanide levels vs. percentile distribution; a  sharp increase
in slope can be seen at 2 mg/1.  The choice of this cutoff point
eliminates data from poorly operated treatment systems and leaves
more than 60 percent of the points in the  data base.   Concentra-
tions of amenable cyanide corresponding to the total  cyanide
values left in the data base were used to  determine a mean ef-
fluent concentration for cyanide amenable  to  chlorination.

               Cyanide Performance Data
Mean Effluent Concentration (mg/1)           0.37       0.16
Variability Factors                       5.0/1.5     5.0/1.5
Daily Maximum Concentration (mg/1)           1.85       0.80
30-Day Average Concentration  (mg/1)          0.56       0.24

Figures 7-77 and 7-78 present the data collection portfolio
(DCP) effluent concentration distribution for each parameter.
The percentages of plants with cyanide levels below  the  cyanide
effluent concentration limitations are as follows:

                         Percent < Daily Maximum Concentration

Parameter                Sampled Data Base        DCP Data Base

Cyanide, Total                  76                      86
Cyanide, Amenable               78                     100
                             VII-152G

-------
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    Percentile Distribution
                                                 80
—I
 100
                          FIGURE  7-77


DCP DATA FOR  EFFLUENT TOTAL  CYANIDE CONCENTRATION DISTRIBUTION
                             VI1-154

-------
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                                                                                           Dialy Maximum =  0.80 mg/1
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                                     30
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 70
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   80
                                                                                                     90
                                                                   FIGURE  7-78


                                       DCP DATA FOR EFFLUENT AMENABLE CYANIDE CONCENTRATION  DISTRIBUTION

-------
ALTERNATIVE CYANIDE TREATMENT  TECHNIQUES

Alternative treatment  techniques  for the destruction of cyanide
include oxidation by ozone,  ozone  with ultraviolet radiation
(oxyphotolysis), hydrogen  peroxide and electrolytic oxidation.
These techniques are presented in  the following paragraphs.

OXIDATION BY OZONE

Ozone may be produced  by several methods,  but the silent electrical
discharge method is predominant in the field.  The silent electrical
discharge process produces ozone by passing  oxygen or air between
electrodes separated by an insulating material.  The electrodes are
usually stainless steel or aluminum.   The  dielectric or insulating
material is usually glass.   The gap or air space between electrodes
or dielectrics  must be uniform and is usually on the order of 0.100
to 0.125 inches.  The  voltage  applied is 20,000 volts or more, and a
single phase current is applied to the high  tension electrode.

Ozone is approximately ten times more soluble than oxygen on a
weight basis in water, although the amount that can be efficiently
dissolved is still slight.   Ozone's solubility is proportional to
its partial pressure and also  depends on the total pressure on the
system.  It should be  noted, however, that it is the oxidizable con-
taminant in the water  that determines the  quantity of ozone needed
to oxidize the  contaminants  present.   A complete ozonation system is
represented, in  Figure  7-79.

Thorough distribution  of ozone in  the water  under treatment is
extremely important for high efficiency of the process.  There are
three methods of destruction of ozone and  they are the emulsion
column, diffusers, and mechanical  injection.

In the emulsion column, the  ozone  gas stream is drawn into the
liquid after it has passed through an injector.  The liquid and
ozonated gas mix in a  central  pipe mounted vertically in a second
column.  The resultant mixture is  discharged at the bottom of the
central pipe, and then rises concurrently  in the annular space be-
tween the center pipe  and  the  outer column.

Ozone may be diffused  through  porous  ceramic or sintered stainless
steel tubes or plates.  The  porosity  of the  material should be
about fifty percent, with pore openings no greater than ninety
microns.  Contact times for  diffusion range  from five to ten minutes
for most applications, and the depth  of diffusions in the contact
tank is usually thirteen to  fifteen feet.  Ozone utilization with
this method approaches an efficiency  of ninety-nine percent.

Mechanical injection is primarily  for special application such as
industrial waste treatment reactors with packed or plate type
columns or in mechanically agitated reactors.

Application and Performance

Ozonation has been applied commercially for  oxidation of cyanides,
phenolic chemicals, and organo-metal  complexes.  It has also been
                             VII-156

-------
      CONTROLS
                     OZONE*
                   GENERATOR
      DRY AIR
RAW WASTE.
                        D
                 I   II    I
                                OZONE
                               REACTION
                                TANK
                                          ixj-
                                                    TREATED
                                                     WASTE
                   FIGURE 7-79
 TYPICAL OZONE  PLANT FOR  WASTE TREATMENT
                    VII-157

-------
studied in the laboratory for applicability  to  photographic waste-
waters with good results.  Ozone  is used  in  industrial  waste treat-
ment, primarily to oxidize cyanide to  cyanate and  to  oxidize phenols
and dyes to a variety of colorless nontoxic  products.

Oxidation of cyanide to cyanate is illustrated  below:

                   CN"1 + 03 = CNO"1 + 02

Continued exposure to ozone will  convert  the cyanate  formed to
carbon dioxide and ammonia if the reaction is allowed  to  proceed;
however, this is not economically practical, and cyanate  can be
economically decomposed by biological oxidation.

Ozone oxidation of cyanide to cyanate requires  1.8  to  2.0 pounds
of ozone per pound of CN  and complete oxidation requires 4.6 to
5.0 pounds of ozone per pound of  CN .  Zinc, copper,  and  nickel
cyanides are easily destroyed to  a nondetectable level, but
cobalt cyanide is resistant to ozone treatment.

The first commercial plant using  ozone in the treatment of cyanide
waste was installed by a manufacturer of  aircraft.  This  plant is
capable of generating 54.4 Kg (120 pounds) of ozone per day.   The
concentration of ozone used in the treatment is approximately 20
mg/1.  In this process the cyanate is hydrolyzed to CO.-, and NH->.
The final effluent from this process passes  into a  lagoon.   Because
of an increase in waste flow the  original installation  has been ex-
panded to produce 162.3 Kg (360 pounds) of ozone per  day.

An electroplating plant (ID 30022) that serves  the  electronics
industry plates gold, silver, copper, and nickel.   Ozone  was
selected for treatment of cyanide bearing waste, and  the  results
were as follows:

     A.   Optimum operating conditions were  determined  to be 1 to
          1.5 moles of ozone/mole CN  at  a pH of 9.0-9.5  in the
          ozone contactor.

     B.   It was established that ozone dosage  is  the most critical
          operating parameter, with 1.0_to 1.5  moles  0_/mole CN
          found to be optimum at  low CN   concentrations  (< 20 mg/1)
          and 1.8 to 2.8 moles 0  /mole CN  at levels  greater than
          40 mg/1.              J

     C.   Cost data based on plant experience were  obtained.
          Treatment operating cost was $1.43/100 gallons  of
          influent cyanide bearing waste  water  and  $1.03/1000
          gallons total waste water.  Total  capital costs were
          $66,613 for this installation but  are estimated at
          $51,200 for an optimized, non-research installation.
                              VII-158

-------
An electroplating plant (ID 30022) that serves  the  electronics
industry plates gold, silver, copper, and nickel.   Ozone  was
selected for treatment of cyanide bearing waste, and  the  results
were as follows:

     A.   Optimum operating conditions were determined  to be  1  to
          1.5 moles of ozone/mole CN  at a pH of 9.0-9.5  in  the
          ozone contactor.

     B.   It was established that ozone dosage  is the most critical
          operating parameter, with 1.0_to 1.5  moles  0_/mole  CN
          found to be optimum at low CN~ concentrations  (< 20 mg/1)
          and 1.8 to 2.8 moles 0_/mole CN  at levels  greater  than
          40 mg/1.              J

     C.   Cost data based on plant experience were  obtained.
          Treatment operating cost was $1.43/100 gallons  of
          influent cyanide bearing waste water  and  $1.03/1000
          gallons total waste water.  Total capital costs were
          $66,613 for this installation but are estimated at
          $51,200 for an optimized, non-research installation.

     D.   The results of three days of sampling are shown below:

                         Day 1           Day 2          Day 3

                      Ir±       Out     In_    Out    Jlri      Out

Cyanide, Total        1.4      .113    .30   .039   2.4      .096
Cyanide, Amenable     1.4      .110    .30   .039   2.389   .096

Advantages and Limitations

Some advantages of ozone oxidation for handling process effluents
are that it is well suited to automatic control, on-site  generation
eliminates treatment chemical procurement and storage problems,
reaction products are not chlorinated organics, and no  dissolved
solids are added in the treatment step.  Ozone  in the presence  of
activated carbon, ultraviolet, and other promoters  shows  promise
of reducing reaction time and improving ozone utilization.  Some
limitations of the process are high capital expense,  possible
chemical interference in the treatment of mixed wastes, and  an
energy requirement of 25 kwh per kilogram of ozone  generated.
Cyanide is not economically oxidized beyond the cyanate  form.

Operational Factors

Reliability;   High, assuming proper monitoring  and  control and
proper pretreatment to control interfering substances.
                               VII-159

-------
     D.   The results of three days of  sampling  are  shown below:

                         Day 1            Day  2          Day 3

                      Ln       Out      In_    Out    Iri      Out

Cyanide, Total        1.4      .113     .30    .039    2.4     .096
Cyanide, Amenable     1.4      .110     .30    .039    2.389   .096

Advantages and Limitations

Some advantages of ozone oxidation for  handling  process effluents
are that it is well suited to automatic  control, on-site generation
eliminates treatment chemical procurement and storage  problems,
reaction products are not chlorinated organics,  and  no dissolved
solids are added in the treatment step.   Ozone in  the  presence  of
activated carbon, ultraviolet, and other promoters shows promise
of reducing reaction time and improving  ozone utilization.   Some
limitations of the process are high capital expense, possible
chemical interference in the treatment  of mixed  wastes, and  an
energy requirement of 25 kwh per kilogram of  ozone generated.
Cyanide is not economically oxidized beyond the  cyanate form.

Operational Factors

Reliability;  High, assuming proper monitoring and control  and
proper pretreatment to control interfering substances.

Maintainability;  Maintenance consists  of periodic removal  of sludge,
and periodic renewal of filters and desiccators  required for the
input of clean dry air, with life a function  of  input  concentra-
tions of detrimental constituents.

Solid Waste Aspects;  Pretreatment to eliminate  substances  which
will interfere with the process may be  necessary.  Dewatering of
sludge generated in the ozone oxidation  process  or in  an "in-line"
process may be desirable prior to disposal.

Demonstration Status

Ozone is useful for application to cyanide destruction.  There
are at least two units presently in operation in the country
(Plant ID'S 14062 and 30022), and additional  units are planned.
There are currently fifteen orders for  industrial  ozonation  cya-
nide treatment systems pending.

Ozone is useful in the destruction of wastewaters  containing
phenolic materials, and there are several installations in opera-
tion in the United States.
                                VI1-160

-------
Research and  development activities within the photographic  industry
have established that ozone is capable of treating  some  compounds
that are produced as waste products.  Solutions of  key  ingredients
in photographic products were composed and treated  with  ozone  under
laboratory conditions to determine the treatability of  these  solu-
tions.  It was found that some of these solutions were  oxidized
almost completely by ozonation and some were oxidized that were
difficult to  treat by conventional methods.  Ozone  breaks down
certain developer components that biodegrade slowly,  including
color developing agents, pheniodone, and hydroxylamine  sulfate.
Developing agents, thiocyanate ions, and formate  ions degrade
more completely with ozone than when exposed to biological de-
gradation.  Thiosulfate, sulfite, formalin, benzyl  alcohol,  hydro-
quinone, maleic acid, and ethylene glycol can be  degraded to  a
more or less  equal degree with either biological  treatment or  ozone.
Silver thiosulfate complexes were also treated with ozone resulting
in significant recovery of the silver present in  solution.   Ozone
for regeneration and treatment of thiosulfate, hydroquinone,  and
other chemicals is currently being utilized by the  photoprocessing
industry.  There are 40 to 50 installations of this nature in  use
at the present time.

OXIDATION BY OZONE WITH UV RADIATION

One of the modifications of the ozonation process is  the simultan-
eous application of ultraviolet light and ozone for the  treatment
of wastewater, including treatment of halogenated organics.   The
combined action of these two forms produces reactions by photo-
lysis, photosensitization, hydroxylation, oxygenation and oxida-
tion.  The process is unique because several reactions  and reac-
tion species  are active simultaneously.

Ozonation is  facilitated by ultraviolet absorption  because both
the ozone and the reactant molecules are raised to  a  higher  energy
state so that they react more rapidly.  In addition,  free radicals
for use in the reactions are readily hydrolyzed by  the  water  pre-
sent.  The energy and reaction intermediates created  by the  intro-
duction of both ultraviolet and ozone greatly reduce  the amount
of ozone compared with a system that utilizes ozone alone.   Figure
7-80 shows a  three-stage UV/ozone system.

A typical process configuration employs three single  stage reactors.
Each reactor  is a closed system which is illuminated  with ultravi-
olet lamps placed in the reactors, and the ozone  gas  is sparged  in-
to the solution from the bottom of the tank.  The ozone dosage
rate requires 2.6 pounds of ozone per pound of chlorinated aroma-
tic.  The ultraviolet power is on the order of five watts of  use-
ful ultraviolet light per gallon of reactor volume.  Operation
of the system is at ambient temperature and the residence  time
per reaction  stage is about 24 minutes.  Thorough mixing is  neces-
sary and the  requirement for this particular system is  20 horse-
power per 1000 gallons of reactor volume in quadrant baffled reac-
tion stages.

                               VI1-161

-------
MIXER

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OZONE



OZONE
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   FIGURE  7-80




    UV/OZONATION
     VII-162  A

-------
A system to treat mixed cyanides  requires  pretreatment that involves
chemical coagulation, sedimentation,  clarification,  equalization,
and pH adjustment.  Pretreatment  is  followed  by a single stage
reactor, where constituents with  low  refractory indices are oxi-
dized.  This is followed by a second, multi-stage reactor which
handles constituents with higher  refractory  indices.   Staging
in this manner reduces the ultimate  reactor  volume required for
efficient treatment.

Application and Performance

The ozone/UV radiation process was developed  primarily for cyanide
treatment in the metal finishing  and  color photo-processing areas,
and it has been successfully applied  to mixed cyanides and organics
from organic chemicals manufacturing  processes.   The  process is
particularly useful for treatment of  complexed  cyanides such as
ferricyanide, copper cyanide and  nickel cyanide,  which are resis-
tant to ozone alone, but readily  oxidized  by  ozone with UV radia-
tion.  A full scale unit to treat metal complexed cyanides has
been installed in Oklahoma, while a  large  American chemical com-
pany in France has installed an on-line unit  for  the  treatment
of cyanides and organics and a similar design is  scheduled for
installation by the same company  in  the United  States.   There
are also two other units known to be  in service,  one  for treating
mixed cyanides and the other for  the  treatment  of copper cyanide.

OXIDATION BY HYDROGEN PEROXIDE

The hydrogen peroxide oxidation treatment  process treats both the
cyanide and metals in cyanide wastewaters  containing  zinc or
cadmium.  In this process, cyanide rinse waters are heated to
49-54°C (120-130°) and the pH is  adjusted  to  10.5-11.8.  Formalin
(37% formaldehyde) is added, while the tank  is  vigorously agitated.
After 2-5 minutes, a proprietary  formulation  (41% hydrogen peroxide
with a catalyst and additives) is likewise added.  After an hour
of mixing, the reaction is complete.  The  cyanide is  converted
to cyanate and the metals are precipitated as oxides  or hydro-
xides.  The metals are then removed  from solution by  either set-
tling or filtration.

The chemical reactions which take place are  as  follows:

               CNr + HCHO + H20 = HOCH2CN  + OH~

The hydrogen peroxide converts cyanide to  cyanate in  a single step:

                    CN~ + H202 = NCO~ + H20

The formaldehyde also acts as a reducer, breaking zinc and cadmium
ions apart from the cyanide:

     Zn(CN)4~2 + 4 HCHO + 4 H20 = 4 HOCH^N + 4 OH~ + Zn+2


                                VII-162  B

-------
The metals subsequently react with  the hydroxyl  ions  formed and
precipitate as hydroxides or oxides:

               Zn+2 + 2 OH~ = ZnO + HO

The main pieces of equipment required for  this process  are two
holding tanks.  These tanks must be equipped  with  heaters  and air
spargers or mechanical stirrers.  These  tanks may  be  used  in a batch
or continuous fashion with one tank being  used for treatment while
the other is being filled.  A settling tank or a filter is needed
to concentrate the precipitate.

Application and Performance

The hydrogen peroxide oxidation process  is applicable to cyanide-
bearing wastewaters, especially those from cyanide zinc and cya-
nide cadmium electroplating.  The process  has been used on photo-
graphic wastes to recover silver and oxidize  toxic compounds such
as cyanides, phenols and "hypo" (sodium  thiosulfate pentahydrate).
Additions of hydrogen peroxide are made  regularly  at  a  large waste-
water treatment plant to control odors and minimize pipe corrosion
by oxidizing hydrogen sulfide.  In  terms of waste  reduction perfor-
mance, this process is capable of reducing the cyanide  level to
less than 0.1 mg/1 and the zinc or  cadmium to less than 1.0 mg/1.

Advantages and Limitations

Chemical costs are similar to those for  alkaline chlorination and
lower than those for  treatment with hypochlorite, and  all free
cyanide reacts and is completely oxidized  to  the less toxic cya-
nate state.  In addition, metals precipitate  and settle quickly,
and they are recoverable in many instances.   However, the  process
requires energy expenditures to heat the wastewater prior  to
treatment.  Furthermore, the addition of formaldehyde results in
treated wastewater having relatively high  BOD values.  Although
cyanates are much less toxic than cyanide, there is not complete
acceptance of the harmlessness of cyanates.

Operational Factors

Reliability;  Hydrogen peroxide oxidation  is  highly reliable due
to its relative simplicity.  There was an  instance found where the
use of this process interfered with the  performance of  a subsequent
clarification operation.

Maintainability;  The process requires very little maintenance other
than periodic removal of sludge from the settling  tank.  The heating
and agitation mechanisms should be checked from  time  to time.

Solid Waste Aspects;  A relatively  small amount  of solid waste is
generated by this process.  In some applications the  sludge can be
recycled to the process line (as in silver recovery from photogra-
phic processing and zinc from plating solutions).


                                VII-163

-------
Demonstration Status

This treatment process was introduced  in 1971 and  is  being used in
several facilities.

Peroxide oxidation is used in three plants  in the  present data
base;  08061, 21058, and 30009.

ELECTROCHEMICAL CYANIDE OXIDATION

Electrochemical cyanide oxidation is used to reduce free  cyanide  and
cyanate levels in industrial wastewaters.   In this process,  waste-
water is accumulated in a storage tank and  then  pumped  to a  reactor
where an applied DC potentital oxidizes the cyanide to  nitrogen,  car-
bon dioxide and trace amounts of ammonia.   The gases  generated are
vented to the atmosphere.  The oxidation reaction  is  accomplished
if concentrations are not greater than 1000 mg/1.  If reaction time
is critical, the process can be accelerated by augmenting the  sys-
tem with a chemical (hypochlorite) treatment as  long  as the  cyanide
concentration level is less than 200 mg/1.  The  process equipment
consists of a reactor, a power supply, a storage tank and a  pump.

Another electrochemical oxidation system employs a low  voltage
anode with a metallic oxide coating.  Upon  application  of an elec-
trical potential several oxidation reactions occur at the anode.
These reactions include the oxidation of chloride  (from common
salt) to chlorine or hypochlorite and  the formation of  ozone,  as
well as direct oxidation at the anode.  Although untested on cya-
nide-bearing wastewaters, this system  shows good potential in  that
area.

Application and Performance

The electrochemical cyanide oxidation  system has been used com-
mercially only for heat treating applications; however, it should
be equally appropriate for other cyanide bearing wastes.   Its
application for plating and photographic process wastewaters is
still in the development stage.  The process can also be  applied
to the electrochemical oxidation of nitrite to nitrate.  Perfor-
mance has been demonstrated on a commercial scale  and shown  to
result in a reduction in the cyanide concentration level  from
3500 mg/1 to less than 1.0 mg/1 in 160 hours.  The process emits
no noticeable odor with adequate ventilation.

Advantages and Limitations

Electrochemical cyanide oxidation has  the advantage of  low opera-
ting costs with moderate capital investment, relative to  alterna-
tive processes.  There is no requirement for chemicals, thereby
eliminating both their storage and control, and  there is  no  need
to dilute or pretreat the wastewater as the process is  most  effi-
cient at high cyanide concentration levels.  However, the process


                               VI1-164

-------
 is less efficient than chemical  destruction at cyanide concentra-
 tions less than 100 mg/1,  and  it is  relatively slow when not accel-
 erated by addition of treatment  chemicals.   Moreover, it will not
 work well in the presence  of sulfates.

 Operational Factors

 Reliability;  Dependent  in large part  upon  incoming cyanide concen-
 trations.  Generally good,  with  only the  pump having any moving
 parts.

 Maintainability;  The reactor  is replaced at infrequent intervals
 and a rebuilt reactor can  be installed within a few hours.

 Solid Waste Aspects;  No solid waste is directly generated  by this
 process.

 Demonstration Status

 There is currently a unit  in operation which is handling the cyanide-
 bearing wastewater generated by  a heat treating operation.   The manu-
 facturer claims that there  is a  potential for future use of the pro-
 cess in both the electroplating  and  photographic industries.  How-
 ever, despite a variety of  experimental programs,  industry  has not
 been enthusiastic about the electrolytic  approach  to cyanide oxida-
 tion.

 Electrochemical cyanide oxidation is used at plants 04224,  18534
 19002, and 30080.

 CHEMICAL PRECIPITATION

 Chemical precipitation is  a classic  waste treatment process for
metals removal  as described under the "Treatment of Common  Metal
Wastes"  heading.  The precipitation  of cyanide  can  be accomplished
although the cyanide is not destroyed.  Waste  streams with  a total
cyanide  content of 2 mg/1 or above have an  expected waste reduction
of 1.5 to 2  orders of magnitude.  These expectations are substan-
tiated with  results from the following plants:

           CONCENTRATION OF TOTAL CYANIDE (mg/1)

      Plant              Raw Waste             Final Effluent

      1057                2.57                       0.024
                          2.42                       0.015
                          3.28                       0.032
      33056                0.20                       0.09
                          0.20                       0.09
      12052                0.46                       0.4
                          0.12                       0.06
                                  VII-165

-------
REVERSE OSMOSIS

As described earlier in this section,  reverse  osmosis is success-
ful at recovering several types of  process  solutions from waste-
water.  Some of these solutions contain  cyanide  such as copper
cyanide, zinc cyanide and cadmium cyanide.   The  recovery of
cyanide solutions prevents the inclusion of cyanide in the waste-
water and obviates the need for further  cyanide  waste treatment.

EVAPORATION

Evaporation is another recovery alternative applicable to cyanide
process baths such as copper cyanide,  zinc  cyanide, and cadmium
cyanide and was described in detail  for  common metals removal.
                               VII-166

-------
TREATMENT OF OILY WASTES AND ORGANICS

Introduction

This subsection presents the treatment systems that are applicable
to oily waste removal for Options 1, 2, and 3; describes  the  treat-
ment techniques for each option; and defines the effluent concen-
tration levels for those options.  Included as wastes in  the  Oily
Wastes Subcategory are the toxic organics (pollutant parameters
1 through 88 and 106 through 112 listed on Table 3-2) that become
combined with the oils during manufacturing and are present in
the oily wastes, as was discussed in Sections V and VI.   (The
abbreviation, TTO, is used to identify the total toxic organics
concentration as was done in previous sections.)

Oily wastes and toxic organics include process coolants and lubri-
cants, wastes from cleaning operations directly following many
other unit operations, wastes from painting processes, and machin-
ery lubricants.  Oily wastes generally are of three types:  free
oils, emulsified or water soluble oils, and greases.  Oil removal
techniques commonly employed in the Metal Finishing Category  in-
clude skimming, coalescing, emulsion breaking, flotation, centri-
fugation, ultrafiltration, reverse osmosis, carbon adsorption,
aerobic decomposition, and removal by contractor hauling.

Table 7-24 presents the three levels of oily waste removal system
options for free oils, combined wastewater, and segregated oily
waste.  The Option 1 oily waste treatment system incorporates the
emulsion breaking process followed by surface skimming (gravity
separation is adequate if only free oils are present), the Option
2 system consists of the Option 1 system followed by ultrafiltra-
tion, and the Option 3 system is the Option 2 system with the addi-
tion of either carbon adsorption or reverse osmosis.  Because emul-
sified oils, or processes that emulsify oils, are used extensively
in the Metal Finishing Category, the exclusive occurrence of  free
oils is nearly nonexistent.  Combined wastewater (e.g.-oils in the
Common Metals Subcategory wastewaters) should contain only oils
that are introduced from rinsing or cleaing operations, inadver-
tent spills, or equipment leakage.  As a result of this, these
wastewaters contain low oil concentrations but have high flow rates,
Because treatment system costs are proportional to the flow of
oil, segregation of oily waste is economically preferable.  Segre-
gated oily waste is that collected from tanks and sumps throughout
a manufacturing facility for separate waste treatment or recovery.

The concentration data and limitations are presented herein for
both combined wastewater and segregated oily wastes.  The combined
wastewater concentrations are applicable to the oils and toxic
organics present in the Common Metals Subcategory wastewaters and
concentration limitations are stated for both the Option 1 and
Option 2 common metals treatment systems.  Three levels of options
are presented for the treatment of segregated oily wastes.
                              VI1-167

-------
           TABLE 7-24




OILY WASTE REMOVAL SYSTEM  OPTIONS
< 	 	
\. WASTE
\ CHARACTERISTICS
TREATMENT OPTION N.

OPTI
OPTION
I
ON 2
OPTION 3
FREE OILS
Combined
or
Segregated
Waste
Gravity
Separator
|
COMBINED WASTEWATER SEGREGATED OILY WASTE
Mixture of free oils, grease, and einulsilied oils
Wastewater from rinsing or .collection from tanks and
cleaning overflow,, spills, sumps
and leakage
Low oil concentration, High oil concentrations
high flow rate low flow rate
Emulsion Breaking with Skimming
Option 1 followed by Ultraf iltration
Option 2 followed by Carbon Adsorption or Reverse Osmosis

-------
TREATMENT OF OILY WASTES FOR COMBINED WASTEWATER

The following paragraphs present the oily waste performance  data
for combined wastewater in the Common Metals Subcategory data  base,
identify the mean concentrations established for oils and  total
toxic organics, define the concentration limitations, and  com-
pare these limitations with the sampled data base and the  DCP  data
base for the Option 1 and Option 2 common metals treatment systems.

Combined Wastewater Performance for Oils - Option 1_ Common Metals
System

Figure 7-81 presents the oil and grease performance data for the
Option 1 common metals treatment system data base for properly
operating systems that was previously developed and discussed.
(See subsection for Common Treatment of Common Metals Wastes).  From
these data the following performance was established for oil and
grease in combined wastewater for the Option 1 common metals
treatment system.

                 Oil and Grease Performance Data
        (Combined Wastewater - Common Metals Option .1

   Mean Effluent Concentration            11.9  mg/1
   Variability Factors (from Table 7-9)   2.9/1.3
   Daily Maximum Concentration            34.5  mg/1
   30-day Average Concentration           15.5  mg/1

Figure 7-82 presents the oil and grease performance data for the
entire Option 1 common metals data base and Figure 7-83 presents
the data collection portfolio (DCP) responses for effluent oil and
grease concentrations from facilities that incorporate Option  1
common metals treatment systems.  The daily maximum concentration
is overlayed on each of these for comparison.  The percentage  of
oil and grease effluent concentrations that are less than  the
daily maximum concentration limitation are 100% for the data base
comprised of properly operating systems, 90.3% for the entire
common metals data base and 71% for the Option 1 DCP data  base.

Combined Wastewater Performance for Oils - Option 2^ Common Metals
System

Figure 7-84 presents the oil and grease concentration data for
the Option 2 common metals treatment system data base.  From these
data, excluding the outlier at an effluent concentration of  56 mg/1
which exceeds the Option 1 daily maximum concentration limitation,
the following performance results.
                              VII-169

-------
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                                 EFFLUENT OIL S. GREASE  CONCENTRATION vs RAW WASTE CONCENTRATION

                                               OPTION 1 COMMON METALS SUBCATEGORY

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EFFLUENT OIL & GREASE CONCENTRATION vs  RAW WASTE  CONCENTRATION
              OPTION 1 COMMON METALS  SUBCATEGORY

              (Entire Metal  Finishing  Data Base)

-------
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                      (Combined Wastewater)
1000

-------
                 Oil and Grease Performance  Data

        (Combined Wastewater; - Common Metals Option  2)


   Mean Effluent Concentration             7.1  mg/1
   Variability Factor                      2.9/1.3
   Daily Maximum Concentration             20.6  mg/1
   30-day Average Concentration            9.2   mg/1


Figure 7-85 shows the data collection portfolio  (DCP) effluent
concentration distribution for oil and grease from plants  that  in-
corporate an Option 2 common metals treatment system.   The  percen-
tages of combined wastewater oil and grease  effluent concentrations
that are less than the Option 2 daily maximum concentration limita-
tion are 88.9% for the sampled data base and  100% for the  DCP data
base .

Combined Wastewater Performance for Total  Toxic Organics

As was discussed in Sections V and VI, the pollutants,  designated
Parameter 1 through 88 and 106 through 112 on Table  3-2 are toxic
organics  that commonly occur in the Metal Finishing Category as
solvents or oil additives.  These have been  grouped together for
control and are identified as total toxic  organics, TTO.
Figure 7-86 presents the raw waste concentration distribution for
the total toxic organics, TTO, in common metals wastewaters.  As
was reported in Section VI (Table 6-1), the mean concentration of
these TTO is 11.3 mg/1 for the entire Metal  Finishing Category
data base.  However, there are three high  outliers (802.,  285.,
and 74.2 mg/1) on Figure 7-86.  These are  considered to result from
the direct discharge of TTO from some source, such as solvent de-
greaser sumps or spent solvent storage, because TTO should  enter
wastewater streams only from cleaning operations as rinses.  Re-
moval of these three outliers, as data not representative of ac-
ceptable TTO disposal, lowers the raw TTO mean concentration to
0.38 mg/1.  This mean raw TTO concentration  is considered charac-
teristic for common metals wastewaters with proper TTO  management
practices being applied.  Table 7-25 presents raw and effluent
total toxic organics performance from treatment systems in  the
Common Metals Subcategory data base that have raw waste concentra-
tions in the same order of magnitude as the  0.38 mg/1 mean  raw
waste concentration.
                              VI1-174

-------
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                                          PERCENTILE  DISTRIBUTION OF TOTAL TOXIC ORGANICS

                                                    IN COMMON METALS WASTEWATERS

-------
                         TABLE 7-25
TOTAL TOXIC ORGANICS PERFORMANCE - COMMON METALS  SUBCATEGORY

Plant ID
02032

04071
06090
06091
06960
17050

19068
21051

27046

30054
Concentration
Raw TTO
1.247
0.121
0.238
0.486
0.149
0.189
1.083
0.477
0.297
0.421

0.179
0.225
0.608
(mg/1)
Effluent TTO
0.077
0.081
0.040
0.052
0.019
0.079
0.030
0.047
0.020
0.012
0.020
0.016
0.012
0.067
Mean Concentration  0.44                           0.04

Based upon the data of Table 7-25, the following performance  is
summarized.

  Total Toxic Organic Performance - Common Metals  Subcategory

  Mean Effluent Concentration                 0.04  mg/1
  Variability Factor                          2.9/1.3
  Daily Maximum Concentration                 0.12  mg/1
  30-day Average Concentration                0.05  mg/1

The performance limitations for oily wastes and total toxic
organics for combined wastewater in The Common Metals Subcategory
are summarized in Table 7-26.

                            TABLE 7-26
             OILS & TTO LIMITATIONS - COMBINED WASTEWATER

                      Common Metals Subcategory

                                         Concentration  (mg/1)
                                    Oils                      TTO
                           Option 1^      Option 2_        Single Option

Mean Effluent Concentration   11.9         7.10             0.04
Daily Maximum Concentration   34.5         20.6             0.12
30-day Average Concentration  15.5         9.20             0.05
                            VII-177

-------
TREATMENT OF SEGREGATED OILY WASTES

Treatment of oily wastes can be carried out most efficiently  if
oils are segregated from other wastes and treated separately.
Segregated oily wastes originate in the manufacturing  areas,
are collected in holding tanks and sumps, and can have oil  and
grease concentrations as high as 400,000 mg/1.  Combined oily
wastes are those generated from washing or rinsing of  oily  parts,
spills, and leakages and generally have lower oil and  grease con-
centrations than concentrated oily wastes and by two or three
orders of magnitude.  Futhermore, oily wastes in combined waste-
water streams, such as common metals wastewaters, require larger
and thus more costly treatment systems for oils removal than do
segregated oily wastewaters because the combined wastewaters have
significantly greater flow rates.  Performance limitations  for
combined wastewater oils and total priority organics are presen-
ted in the preceding subsection.

Treatment systems for segregated oily wastes consist of separa-
tion of the oily wastes from the water.  This separation can re-
quire several different steps depending on the character of the
oily wastes involved.  If the oils are all of a free or floating
variety, physical means such as decantation or the use of a grav-
ity oil separator should be used to remove the oils.   If the oily
wastes are emulsified, techniques such as emulsion breaking or
dissolved air flotation with the addition of chemicals are  necessary
to accomplish removal of the oils.  Once the oil-water emulsion is
broken, the oily waste is physically separated from the water by
decantation or skimming.  After the oil-water separation has been
carried out, the water is sent to the precipitation/sedimentation
unit described under the "Treatment of Metals Wastes" heading for
removal of metals.

Segregated Oily Waste Treatment System - Option 1

The Option 1 system for the treatment of segregated oily waste-
water consists of emulsion breaking followed by skimming, as is
illustrated in Figure 7-87.  The emulsion breaking is effected
by the addition of chemicals (alum and polymers) to accomplish
coagulation and flocculation of the oily wastes.  These float-
ing oily wastes are then removed via skimming to complete the
Option 1 level of treatment.

Treatment alternatives to the Option 1 system that are presently
employed in the metal finishing industry include dissolved  air
flotation, coalescing gravity separators, thermal emulsion break-
ing and the use of centrifugation or ultrafiltration to reduce
the oil concentration of the wastewater prior to emulsion break-
ing.  These alternative techniques, as well as adsorption techni-
ques, thermal emulsion breaking, aerobic decompositon, and  contractor
hauling are described in the subsection entitled "Alternative Oily
Waste Treatment Techniques".
                            VII-178

-------
                     Segregated Oily Wastewater
                             Emulsion
                             Breaking
        Oily Wastes
Skimming
                                T
                      To Metals/Solids Renoval
                    FIGURE  7-87
TREATMENT OF  SEGREGATED OILY WASTES  - OPTION 1
                   VII-179

-------
The Option 1 treatment system  is employed  extensively within the
metal finishing data base for  treatment of segregated oily waste,
but because of the increasing  price of oil, metal  finishing plants
are tending toward the use of  treatment techniques  such as ultra-
filtration, reverse osmosis, or centrifugation  for  the recovery
and direct reuse of oils.

The following paragraphs describe the emulsion  breaking and skim-
ming techniques that are applicable to the removal  of oily wastes
for Option 1 in the Oily Waste Subcategory.

EMULSION BREAKING

Description of_ the Process

Emulsion breaking is a process by which emulsified  oils are re-
moved from oil/water mixtures.  Emulsified oils  are commonly used
as coolants, lubricants, and antioxidants  for many  of the  unit  oper-
ations performed in the Metal  Finishing Category.   Methods of
emulsion breaking include a variety of chemical  processes, thermal
processes, and combinations of the two processes.   These techniques
are discussed in the following paragraphs.

Chemical emulsion breaking can be accomplished either as a batch
process or as a continuous process.  A typical system (with skim-
ming incorporated) is illustrated in Figure 7-88.   The  mixture  of
emulsified oils and water is initially treated by the addition  of
chemicals to the wastewater.  A means of agitation,  either mechan-
ical agitation or by increasing the turbulence of the wastewater
stream, is provided to ensure  that the chemical  added and  the
emulsified oils are adequately mixed to break the oil/water emul-
sion bond.  Finally the oily residue (commonly called scum)  that
results rises to the surface and is separated from  the  remaining
wastewater by a skimming or decanting process.   The  skimming  pro-
cess can be accomplished by any of the many types of  mechanical
surface skimmers that are presently in use.  Decanting  methods
include removal of the oily surface residue via  a technique such
as controlled tank overflow or by removal  of the demulgated waste-
water from the bottom of the tank.  Decanting can be  accomplished
with a series of tap-off lines at various  levels which  allow  the
separated oils to be drawn off the top or  the wastewater to be
drawn off the bottom until oil appears in  the wastewater line.
With any of these arrangements, the oil is  usually  diverted to
storage tanks for further processing or hauling  by  a  licensed
contractor.

Chemical emulsion breaking can be accomplished by a  large  variety
of chemicals which include acids, salts, or polymers.   These  chemi-
                           VI1-180

-------
                           Chemical Addition
       Emulsified Oils
i—1
00
                                                                 Skimmer
                                 Mixing Tank
immer f

_\L
                                                                                   Oils
                                                            Combination Flotation

                                                                     And


                                                                Settling Tank
                          Treated Wastewater
                                                                    Sludge
                                                  FIGURE 7-88
                                  TYPICAL EMULSION BREAKING/SKIMMING  SYSTEM

-------
cals are sometimes used separately, but often  are  required  in com-
bination to break the various emulsion that are  common  in  the waste-
water.  Acids are used to lower the pH to  3 or 4 and  can cleave  the
ion bond between the oil and water, but can be very expensive un-
less acid rich wastewaters, such as pickling wastes,  can be  used.
Acids are more commonly employed in oil recovery systems than in
oily waste removal systems.  Iron or aluminum  salts such as  ferrous
sulfate, ferric chloride, or aluminum sulfate  are  more  commonly
used because they are less expensive.  These salts combine with
the wastewater to form acids which in turn lower the  pH and  break
the oil/water bond (and have the additional benefit that these
salts aid in agglomeration of the oil droplets), but  the use of
these salts produces more sludge because of the  addition of  iron
or aluminum.  Polymers, such as polyamines or polyacrylates  and
their copolymers, have been demonstrated to be effective emulsion
breakers and generate less sludge than do metal  salts.  The  Option
1 treatment system costing, presented in Section VIII,  is based
upon the use of aluminum sulfate plus a small quantity  of polymer,
as the emulsion breaking chemicals.

After chemical addition, the mixture is agitated to ensure com-
plete contact of the emulsified oils with the demulsifying agent.
With the addition of the proper amount of chemical and  thorough
agitation, emulsions of 5% to 10% oil can be reduced  to approxi-
mately 0.01% remaining emulsified oil.  The third  step  in the emul-
sion breaking process is to allow sufficient time  for the oil/water
mixture to separate.  Differences in specific gravity will permit
the oil to rise to the surface in approximately  2 hours.  Heat can
be added to decrease the separation time.  After separation,  the
normal procedure involves skimming or decanting  the oil from the
tank.

Application and Performance

Emulsion breaking technology can be applied to the treatment of
emulsified oil/water mixtures in the Metal Finishing  Category
wherever it is necessary to separate oils, fats, soaps, etc.  from
wastewaters.

The performance attainable by a chemical emulsion breaking process
is dependent on addition of the proper amount of de-emulsifying
agent, good agitation and sufficient retention time for complete
emulsion breaking.  Since there are several types of  emulsified
oils, a detailed study should be conducted to determine the  most
effective treatment techniques and chemicals for a particular
application.

The analytical results for samples taken before  and after emulsion
breaking processes are shown in terms of concentration  (mg/1) in
Table 7-27.
                               VII-182

-------
                           TABLE 7-27
               EMULSION BREAKING PERFORMANCE DATA
Parameter

Oil and Grease
TOC
TSS
TPO
       Plant ID 1058

     Influent    Effluent

     3320.          42.
     3130.          262.
     137.           12.
     2.90           1.46

             Plant ID 12095
               Plant ID 30165

             Influent    Effluent
             210.
             210.
             520.
             0.26
Parameter

Oil & Grease
TOC
TSS
TTO
Parameter

Oil & Grease
TOC
TSS
TTO
     Day 1
Influent  Effluent
        Day 2
   Influent  Effluent
              24.
              65.
              6.0
              0.06
              Day 3
         Influent  Effluent
12500.    27.       2300.
1280.     950.      2950.
2000.     153.      1650.
6.14      1.19      3.15

      Plant ID 38040
             52.
             1790.
             187.
             0.80
         13800.
         1140.
         3470.
         6.50
        18.
        881.
        63.
        0.48
                                               Plant  ID  40836
     Influent

     192.8
     143.
     74.
     4.44
Effluent

10.6
139.
37.
1.60
Influent

6060.
9360.
2612.
21.4
Effluent

98.
850.
46.
8.60
Advantages and Limitations
The main advantage of the chemical emulsion breaking process  is  the
high percentage of oil removal possible with this system.  for pro-
per and economical application of this process, the oily wastes
(oil/water mixture) should be segregated from other wastewaters
either by storage in a holding tank prior to treatment or be  fed
directly into the oily waste removal system from major collection
points.  Further, if a significant quantity of ree oils are pre-
sent, it is economically advantageous to precede the emulsion break-
ing with a gravity separator.  Chemical and energy costs can  be  high,
expecially if heat is used to accelerate the process.

Operational Factors

Reliability;   Chemical emulsion breaking can be highly reliable
if adequate analysis is performed prior to the selection of chemi-
cals and proper operator training is provided to ensure that  the
established procedures are followed.
                              VII-183

-------
Maintainability;  For chemical emulsion  breaking,  routine mainten-
anceisrequired on pumps, motors,  and valves  as  well as periodic
cleaning of the treatment  tank to remove any  sediment which may
accumulate in the tank.  The use of acid or acidic conditions will
require a lined tank, and  the lining should be checked periodically.

Solid Waste Aspects

Emulsion breaking generates sludge  which requires  proper disposal.

Demonstration Status

Emulsion breaking is a common technique  used  in  industry and it is
a proven method of effectively treating  emulsified wastes.

Emulsion breaking is in use at 23 plants in the present data base
and these are identified in Table 7-28.

                         TABLE 7-28
     METAL FINISHING PLANTS EMPLOYING EMULSION BREAKING
     01058
     01063
     03041
     06679
     11129
11477
12075
12076
12080
12091
12095
13041
30158
20159
20173
20247
20249
20254
30135
30153
33050
33120
33127
33179
36074
38040
40836
46713
30165
SKIMMING
Description of the Process

Skimming is used to remove floating wastes and normally  takes place
in a tank designed to allow the debris  (with a specific  gravity less
then water) to rise and remaon on the surface.  Skimming devices
are therefore suited to the removal of  oily wastes  from  raw  waste
streams after demulsification.  Common  skimming mechanisms include
the rotating dry type, which picks up oil from the  surface of the
water as it rotates.  A knife edge scrapes oil from the  drum and
collects it in a trough for disposal or reuse.  The water portion
is then allowed to flow under the rotating drum.  Occasionally,
an underflow baffle is installed after  the drum;  this  has the ad-
vantage of retaining any floating oil which escapes the  drum skim-
mer.  The belt type skimmer is pulled vertically  through the
water, collecting oil from the surface  which is again  scraped off
                               VI1-184

-------
and collected in a tank.  Gravity separators, such as the API  type,
utilize overflow and underflow baffles to skim a floating oil  layer
from the surface of the wastewater.  An overflow-underflow baffle
allows a small amount of wastewater (the oil portion) to flow  over
into a trough for disposition or reuse while the majority of the
water flows underneath the baffle.  This is followed by an overflow
baffle, which is set at a height relative to the first baffle  such
that only the oil bearing portion will flow over the first baffle
during normal plant operation.  A diffusion device, such as a  ver-
tical slit baffle, aids in creating a uniform flow through the sys-
tem and increasing oil removal efficiency.

Application and Performance

Oil skimming is used in the Metal Finishing Category to remove oily
wastes from many different process wastewater streams.  Skimming is
applicable to any waste stream containing pollutants which float to
the surface.  Skimming is used in conjunction with emulsion breaking,
dissolved air flotation, clarifiers, and other sedimentation devices.

API or other gravity-type separators are more suitable for use where
the amount of surface oil flowing through the system is consistently
significant as with fee oils.  Drum, belt, or rotary type skimmers
are applicable to waste streams which carry smaller amounts of float-
ing oily waste and where surges of floating oil are not a problem.
The use of a gravity separator system preceding emulsion breaking
is a very effective method of removing free oil constituents from
oily waste streams.  Examples of the performance of skimmer systems
are shown below:
     Plant     Skimmer Type
     06058          API
     06058          Belt
     06641          Drum
     11477          Belt
Oil &
Grease
In (mg/1)
*149779.
 19.4
 232.
 61.
Oil &
Grease
Out (mg/1)

*17.9
 8.3
 63.7
 14.
     * Average of three days sampling results

Advantages and Limitations

Skimming as a pretreatment is effective in removing naturally float-
ing waste materials, such as free oils, and improves the performance
of subsequent downstream treatments.

Many pollutants,  particularly dispersed or emulsified oil, will not
float "naturally" but require additional treatments.  Therefore,
skimming alone will not removal all the pollutants capable of being
removed by more sophisticated technologies.
                           VI1-185

-------
OPERATIONAL FACTORS
              Because of its simplicity, skimming  is a  very  reliable
Reliability;
technique.

Maintainability;  A mechanical skimming mechanism requires periodic
lubrication, adjustment, and replacement of worn parts.

Solid Waste Aspects;  The collected layer of debris  (scum) must be
disposed of in an approved manner.  Because relatively large quanti-
ties of water are present in the collected wastes, direct combusion
or incineration is not always possible.

Demonstration Status

Skimming is a common operation utilized extensively  in industrial
waste treatment systems and is used by 94 plants in  the metal fini-
shing data base.  These are identified in Table 7-29.

                         Table 7-29
          Metal Finishing Plants Employing Skimming
          01063
          04233
          04892
          06041
          06051
          06058
          06062
          06084
          06086
          06116
          06679
          07001
          09047
          09181
          11113
          11129
          11137
          11152
          11477
          12007
          12033
          12042
          12075
          12076
                         12080
                         12091
                         13324
                         14001
                         14062
                         15010
                         15033
                         16032
                         17030
                         18091
                         18538
                         19106
                         20001
                         20064
                         20075
                         20106
                         20157
                         20158
                         21059
                         20165
                         20173
                         20177
                         20249
                         20254
20471
20483
20708
22031
23075
25031
25339
28075
28115
28116
28125
30050
30079
30135
30150
30151
30153
30516
31040
31067
33024
33050
33120
33127
33178
33179
33292
35001
36074
36102
36131
36155
36623
38040
38050
38217
40070
41084
41115
44062
46025
46032
46713
47025
47048
47049
Segregated Oily Waste Treatment System Performance - Option  1

Figure 7-89 presents the Option 1 system performance data base  for
segregated oily waste treatment systems that were operating  properly
when sampled.  The performance data that result are summarized  as
follows:
                               VII-186

-------
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                                                              FIGURE 7-89


                                            SEGREGATED OIL & GREASE EFFLUENT PERFORMANCE


                                                               OPTION  1

-------
     Segregated Oil and Grease  Performance  Data  - Option I.

     Mean Effluent Concentration              23.8 mg/1
     Variability Factor                       2.9/1.3
     Daily Maximum Concentration              69.0 mg/1
     30-Day Average Concentration             30.9 mg/1

Figure 7-90 presents the segregated oily waste data base for  the  en-
tire Metal Finishing Category oily waste data base.   The daily  maxi-
mum concentration is overlayed  for comparison and the percentage  of
oil and grease concentrations that are less  than  the  daily maximum
concentration are 100% for the  properly operated  sampled data base
of Figure 7-89 and 77.8% for the entire oily waste data  base.

Segregated Oily Wastewater Performance for  Total  Toxic Organics

As was discussed in Section V and VI, the pollutants, designated
Parameter 1 through 88 and 106  through 112  on Table 3-2, are  toxic
organics that commonly occur in the Metal Finishing Category  as
solvents or oil additives.  These have been grouped together  for
control and are identified as total toxic organics, TTO.  Figure
7-91 presents the raw waste concentration distribution for the
total toxic organics, TTO, in segregated oily wastewaters. As
was reported in Section VI (Table 6-6), the mean  concentration  for
these TTO is 112. mg/1 for the  entire Metal Finishing Category  data
base.  However, there are five  high outliers  (1922.,  1038., 839.,
110., and 57.4 mg/1) on Figure  7-91.  These are considered to re-
sult from the direct discharge  of TTO from  some source,  such  as
solvent degreaser sumps or spent solvent storage,  because  TTO
should enter wastewater streams only from cleaning operations or
rinses.  Removal of these five  outliers, as data  not  representative
of acceptable TTO disposal, lowers the raw  TTO mean concentration
to 5.28 mg/1.  This mean raw TTO concentration is  considered  charac-
teristic for segregated oily wastewaters with proper  TTO management
practices being applied.  Table 7-30 presents raw and effluent  total
toxic organics data from sampled plants that employ an Option 1
segregated oily waste treatment system.  Based upon the  performance
data of Table 7-30, a total toxic organics  removal efficiency of
80% is established for the Option 1 segregated oily waste  treat-
ment system and therefore a mean effluent TTO concentration of
1.06 mg/1 results.  The total toxic organics concentration limi-
tations are summarized as follows:

                           TABLE 7-30
  TOTAL TOXIC ORGANIC PERFORMANCE - SEGREGATED OILY WASTE  OPTION  1

                                      Concentration (mg/1)
              Plant ID            Raw TTO          Effluent TTO

               06641                 2.58              0.66
               12095                 6.14              1.19
                            VII-188

-------
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                                                             FIGURE 7-90


                            SEGREGATED  OIL & GREASE EFFLUENT CONCENTRATION vs RAW WASTE CONCENTRATION

                                                               OPTION  1


                                                 (Entire Metal Finishing Category Data Base)
                                                                                                                            10

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                                                             FIGURE 77-91

                                           PERCENTILE DISTRIBUTION OF TOTAL TOXIC ORGANICS
                                                    IN SEGREGATED OILY WASTEWATERS

-------
                     TABLE 7-30 (Con't)
TOTAL TOXIC ORGANIC PERFORMANCE - SEGREGATED OILY WASTE OPTION  1

                                   Concentration (mg/1)
               Plant _ID       Raw TTO        Effluent TTO

               12095           3.15               0.80
               12095           6.50               0.48
               38040           4.44               1.60
               38217           4.93               0.95
               38217           4.11               0.66

         Mean Concentration    4.55               0.91

      .  -ff.  .        (Raw TTO-Effluent TTO) 100   Qna
Removal  Efficiency = v	     = 80%
                          RAW TTO

  Total  Toxic Organics Performance - Segregated Oily Waste Option  i_

  Mean Effluent Concentration                         1.06  mg/1
  Variability Factor                                  2.9/1.3
  Daily  Maximum Concentration                         3.07  mg/1
  30-day Average Concentration                        1.38 mg/1

The performance limitations for oily wastes and total toxic organics
for segregated oily wastes with Option 1 treatment in the Oils  Sub-
category are summarized in Table 7-31.

                         Table 7-31
       OPTION J. LIMITATIONS - OILY WASTE SUBCATEGORY

                                      Concentration (mg/1)

                                   Oil &^ Grease        TTO

Mean Effluent Concentration             23.8           1.06
Daily Maximum Concentration             69.0           3.07
30-Day Average Concentration            30.9           1.38

Segregated Oily Waste Treatment System - Option 2_

The Option 2 treatment system for segregated oily wastes is illustrated
in Figure 7-92.  The system consists of the Option 1 treatment  sys-
tem (emulsion breaking with skimming) plus the addition of an ultra-
filtration unit.  The ultrafilter's purpose is to further purify
water which is to be ultimately discharged.  The ultrafiltration
unit removes quantities of oil and toxic organics not removed during
Option 1 treatment, as well as removing metals and other solids.
                             VI1-191

-------
                            Segregated
                            Oily Wastes
Oily Wastes
Oily Wastes
Emulsion Breaking
      And
    Skimming
 Ultrafiltration
                     To Metals/Solids Removal
                   FIGURE 7-92
 TREATMENT OF SEGREGATED OILY WASTES - OPTION 2
                     VI1-192

-------
ULTRAFILTRATION

Description of the Process

Ultrafiltration (UF) is a process using semipermeable polymeric
membranes to separate emulsified or colloidal materials dissolved
or suspended in a liquid phase by pressurizing the liquid  so  that
it permeates the membrane.  The membrane of an ultrafilter forms a
molecular screen which separates molecular particles based on  their
differences in size, shape, and chemical structure.  The membrane
permits passage of solvents and lower molecular weight solutes
while barring dissolved or dispersed molecules above a predeter-
mined size.  At present, an ultrafilter is capable of removing
materials with molecular weights in the range of 1,000 to  100,000.

In the ultrafiltration process, the feed solution is pumped through
a tubular membrane unit.  Water and some low molecular weight mater-
ials pass through the membrane under the applied pressure  of  .767
kg/cm  (10 to 100 psig).  Emulsified oil droplets and suspended
particles are retained, concentrated, and removed continuously.
In contrast to ordinary filtration, retained materials are washed
off the membrane filter rather than held by the filter.  Figure
7-93 illustrates the ultrafiltration process.

The pore structure of the membrane acts as a filter, passing  small
particles, such as salts, while blocking larger emulsified and
suspended matter.  The pores of ultrafiltration membranes  are much
smaller than the blocked particles.  Therefore, these particles
cannot clog the membrane structure.  Clogging of the membrane by
particles near the minimum removal size can be minimized by proper
selection of the membrane to suit the wastewater to be treated.

Once a membrane is chosen that provides maximum attainable removal
of the desired particles, the next most important design criterion
is the membrane capacity.  Here the term flux is used.  Flux  is the
volume of water passed through the membrane area per unit  time-
The standard units are cu m/day/sq m (gpd/sq ft).  The typical flux
is .42 to 8.48 cu m/day/sq m (5 to 1000 gph/sq ft).  Both  membrane
equipment and operating costs increase with the membrane area
required.  It is, therefore, desirable to maximize flux.

Membrane flux is normally dependent on operating pressure,  temp-
erature, flux velocity, solids concentration (both total dissolved
solids and total suspended solids), membrane permeability,  membrane
thickness, and fluid viscosity.  Membrane flux is also affected by
the surface tension of the solution being processed.  With a  fixed
geometry, membrane flux will increase as the fluid velocity is
increased in the system.  This increase in fluid velocity  will re-
quire greater capacity and more horsepower.  Less membrane area is,
therefore, required per unit of effluent to be treated with higher
fluid velocities;  membrane replacement and initial capital costs
decrease.  Opposing these cost decreases is the increase in power
and its resultant cost.
                             VI1-193

-------
ULTRAFILTRATION
                           MACROMOLECULES
\
P=10-50 PSI
  MEMBRANE
                                a       *
                                 WATER    SALTS
                                      'MEMBRANE
            PERMEATE
           •   *  t.    • •     i •/      •   L
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           « • o* *o ; °  ' 0«  '  Vo.  • o. ;o: ;
           ED*  V " *°••*.••"  1  *  o *• 'CONCENT
                '                         ~
       FEED



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           .            .
              jf 4  •••••
o  . CONCENTRATE



      ' 0 *.0
                                   . •   .
          O   OIL  PARTICLES  •DISSOLVED SALTS AND LOW-


                             MOLECULAR-WEIGHT ORGANICS
                     FIGURE  7-93


     SIMPLIFIED ULTRAFILTRATION FLOW  SCHEMATIC
                       VI1-194

-------
Application

Ultrafiltration is employed in metal finishing plants for the separ-
ation of oils, toxic organics, and residual solids.  The major appli-
cations of ultrafiltration in the metal finishing industries has been
to electropainting wastes and oily wastewaters.  Successful commercial
use has been proven for the removal of emulsified oils from waste-
water and for recovery of rinse water and detergent solutions in
phosphate washers.  Recovery operations are common because of the
increasing value of oils, but ultrafiltration is used for end-of-pipe
treatment in industrial plants.

Ultrafiltration is a proven technique for the removal of oily or
paint contaminated wastes from the process waste streams.  This per-
mits reuse of both the permeate and concentrate.  With segregated
oily wastes, the concentrate is essentially the recovered oils and
application of ultrafiltration for this purpose is increasing.
Ultrafiltration of the waste from electropainting (electrocoating)
provides an excellent example of this process.  Car manufacturers
and many other U.S. companies use electropainting for priming pur-
poses.  In this application, the ultrafiltration unit splits the
electropainting rinse water circulating through the unit into a
permeate stream and paint concentrate stream.  The permeate is re-
used for rinsing, and the concentrate is returned to the electro-
painting bath.

Bleeding a small amount of the ultrafiltrate, which contains low
suspended solids and generally two or three percent of organic
solids, to the waste system enables ionic contaminants to be re-
moved from the paint itself.  Situations where tanks of 150,000 to
190,000 liters (40,000 to 50,000 gallons) of paint were periodi-
cally dumped because of contamination have now been eliminated by
using ultrafiltration, thus reducing effluent problems arising
from this dumping process.


The permeate or effluent from the ultrafiltration unit is normally
of a quality that can be reused in industrial applications or dis-
charged directly.

Advantages and Limitations

Ultrafiltration is sometimes an attractive alternative to chemical
treatment because of lower capital equipment, installation, and
operating costs with a very high oil removal efficiency.  Little,
if any, pretreatment is required and because of its compact equip-
ment, it utilizes only a small amount of floor space-  It provides
a positive barrier between oil and effluent which eliminates the
possibility of oil discharge which might occur due to operator error.
                            VI1-195

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A limitation of ultrafiItration  for  treatment  of  process  effluents
is its narrow temperature range  (18°C  to  30°C)  for  satisfactory
operation.  Membrane life is decreased with  higher  temperatures,
but flux increases at elevated temperatures.   Therefore,  surface
area requirements are a function of  temperature and become  a  trade-
off between initial costs and replacement costs for the membrane.
In addition, ultrafiltration is  unable to handle  strong oxidizing
agents, some solvents,  and other organic  compounds  which  can  cause
dissolution of the membrane.

Operational Factors

Reliability:  The reliability of an  ultrafiItration system  is de-
pendent on the application of proper filtration to  incoming waste
streams to prevent membrane damage.

Maintainability;  A limited amount of regular  maintenance is  re-
quiredfor the pumping system.   In addition, membranes must be
periodically changed.

Solid Wast (5 Aspects:  Ultraf iltration is used primarily for re-
covery of solids and liquids.  It therefore eliminates solid waste
problems when the solids (e.g., paint solids) can be recycled to
the process.  Otherwise, the stream containing solids must be
treated by additional end-of-pipe equipment.

Demonstration Status

The ultrafiltration process is well developed and is commercially
available for the treatment of wastewater or the recovery of cer-
tain liquid and solid constituents.  Ultrafiltration is used at 20
plants in the present Metal Finishing Category data base and these
are identified in Table 7-32.

                         Table 7-32
      Metal Finishing Plants Employing Ultrafiltration


                    06062          25010
                    06071          30100
                    06102          30516
                    12065          31022
                    12074          31032
                    13041          33092
                    13324          33617
                    15193          36074
                    19462          38217
                    23076          44048
                             VI1-196

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 Segregated Oily Waste  Treatment  System Performance_ - Option 2

 The raw waste and  effluent  concentrations of oils and toxic organics
 foe streams entering  into and  discharged from ultrafiltration systems
 in the data base are  displayed in  Tables 7-33 and 7-34.  The perfor-
 mance  (removal efficiency)  of  these  ultrafiltration systems is tabu-
 lated  for oil removal  and for  the  removal of toxic organics.  Removal
 performance was calculated  by  computing the percentage of oil removal
 at each plant using ultrafiltration  and then finding the mean of the
 individual performances.  For  both oils and toxic organics, the re-
 moval  performances was calculated  by the following formula:
     Removal Efficiency  =
                      (raw waste - effluent)!00
                          raw waste
                          TABLE  7-33
    ULTRAFILTRATION PERFORMANCE  DATA  FOR  OIL  &  GREASE REMOVAL
 Plant
 IE)

 13041
 13041
 13041
 13324
 15193
 19762
 19762
 30516
 38217
 38217
Oil & Grease Concentration  (mg/1)
      In          "   Out
     95.0
     1,540.
     38,180.
     31,000.
     1,380.
     3,702
     1,102
     7,500
     360
     70.0
               22.0
               52.0
               267.
               21.4
               39.0
               167.
               195.
               640.
               18.0
               10.0
                        Removal
                      Efficiency(%)

                          76.8
                          96.6
                          99
           .3
         99.9
         97.2
         95
         82
         91
         95.0
         85.7
                            ,2
                             3
                             5
                   Mean Removal Efficiency
                                        92.0%
                          TABLE 7-34
 ULTRAFILTRATION PERFORMANCE DATA FOR TOTAL TOXIC ORGANICS
Plant
 ID

13041
13324
15193
19462
19462
30516
  Oil
& Grease
In
Concentration
     1037
     12.0
     802.
     1425
     853.
     57.4
      Out

      14.8
      1.48
      80.0
      233.
      202.
      4.54
[/!_)_   Removal
    Efficiency(%)

       98.6
              Mean Removal Efficiency
                                87.7
                                89.9
                                83.7
                                76.3
                                92.1
                                      88.0%
                             VII-197

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These performances were then applied to  the  effluents which were
found discharging from the Option 1 treatment  system in order to
calculate effluents for the Option 2 treatment system.

After computation, the following results were  found  for the Option
2 segregated oily waste treatment system for the  Oily Waste Sub-
category.
Parameter

Oil and Grease
Total Toxic
 Organics
Mean
Effluent From
Option 1

     23.8
     1.06
Mean
Remova I
Efficiency

   92%
Mean
Effluent
Option 2

  1.90
  0.13
                                                                 From
Based upon these mean concentrations, the Option  2  concentration
limitations for segregated oily waste treatment are as  follows:

        Segregated Oily Waste Performance -  Option  2^

                                    Oils & Grease        TTO
       Mean Effluent Concentration      1.90
       Variability Factor               2.9/1.3
       Daily Maximum Concentration      5.51
       30-day Average Concentration     2.47
                                     0.13
                                     2.9/1.3
                                     0.38
                                     0.17
A comparison of the performance limitations  for  the  Option 1  and
Option 2 segregated oily waste treatment systems  is  presented in
Table 7-35.

                          TABLE 7-35

          OPTION 1 AND OPTION 2 PERFORMANCE  LIMITATIONS
           FOR SEGREGATED OIL WASTE TREATMENT  SYSTEMS
                                   OPTION 1

                          Oils & Grease   TTO
                                       OPTION 2

                              Oils & Grease   TTO
Mean Effluent Concentration    23.8
Daily Maximum Concentration    69.0
30-day Average Concentration   30.9
                      1.06
                      3.07
                      1.38
               1.90
               5.51
               2.47
           0.13
           0.38
           0.17
Segregated 0_ily Waste Treatment System - Option  .3
Description - The Option 3 treatment system  for  segregated  oily
wastes is illustrated in Figure 7-94.  As shown,  the  system is  com-
                              VII-198

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                             Segregated
                             Oily Wastes
    Oily Wastes
Emulsion Breaking
       And
    Skimming
    Oily Wastes
 Ultrafiltration
                             Optional
                            Pre-filter
    Oily Wastes
 Reverse Osmosis
        Or
Carbon Adsorpsion
                                 I
                      To Metals/Solids Removal
                     FIGURE 7-94
TREATMENT OF SEGREGATED  OILY WASTES -  OPTION  3
                       VI1-199

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prised of the components that make  up  the  Option  2  oily waste treat-
ment system with the addition of a  final  filtering  component.  Two
possibilities for this filtration process  are  reverse  osmosis and
carbon adsorption.  A reverse osmosis  unit or  a carbon adsorption
unit will remove oils and toxic organics  that  are not  removed by
Option 2 system treatment.   In both  the case of reverse osmosis and
carbon adsorption, heavy loadings of oil  will  render  the unit inef-
fective.  Oil can plug the membrane  of a  reverse  osmosis system or
foul a carbon adsorption system.  To prevent this from happening,
an optional pre-filter has been added  to  the Option 3  model  prior
to reverse osmosis and carbon adsorption.   As  with  Options  1 and 2,
the effluent from the Option 3 oily waste  treatment system  is directed
to the solids removal components of  the metal  waste treatment system.

The following paragraphs describe reverse  osmosis and  carbon adsorp-
tion techniques that are applicable  for the treatment  of segregated
oily wastes in Option 3.

REVERSE OSMOSIS

Reverse osmosis, which is explained  in detail  in  the section "Treat-
ment of Common Metal Wastes", is the process of applying a pressure
to a concentrated solution and forcing a permeate through a  semi-
permeable membrane into a dilute solution.  This principle has
found use in treating oily wastes.   In terms of oily wastewater,
reverse osmosis is used primarily as a polishing mechanism to re-
move oils and metals that are still remaining  after treatment such
as emulsion breaking or ultrafiltration.   Examples  of  reverse
osmosis performance are presented below.
Parameter
       30166
               38040
               Day 1
                         38040
                         Day 2
             Influent  Effluent  Influent  Effluent   Influent   Effluent
Oil&Grease
TOG
BOD
TSS
Iron
TTO
117.
371.
183.
9.6

1.46
8.5
78.
60.
1.2

0.55
10.6
139.
60.
37.
1.91
4.30
4.1
94,
58.
14.
.182
1.04
129.
116.
27.
13.
1.94
41.
108,
53.
1.0
.22
CARBON ADSORPTION
Description ojf the Process

Carbon adsorption in industrial wastewater treatment  involves  pas-
sing the wastewater through a chamber containing activated  carbon.
The use of activated carbon has been proven to be applicable  for
removal of dissolved organics from water and wastewater.   In  fact,
it- is one of the most efficient organic removal processes  available.
This process is reversible, thus allowing activated carbon  to  be  re-
generated and reused by the application of heat and steam.
                             VI1-200

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The term activated carbon applies to any amorphous form of carbon
that has been specially treated to give high adsorption capacities.
Typical raw materials include coal, wood, coconut shells, petroleum
base residues and char from sewage sludge pyrolysis.  A carefully
controlled process of dehydration, carbonization, and oxidation
yields a product which is called activated carbon.  This material
has a high capacity for adsorption, 500-1500 square meters/gram,
resulting from a large number of internal pores.  Pore sizes gener-
ally range from 10-100 angstroms in radius.

Activated carbon removes organic contaminants from water by the
process of adsorption, or the attraction and accumulation of one
substance on the surface of another.  Activated carbon has a prefer-
ence for organic compounds and, because of this selectivity, is
particularly effective in removing organic compounds from aqueous
solutions.

Some important but general rules based on considerations relating to
carbon adsorption capacity are:

.    Higher surface area will give a greater adsorption capacity.

     Larger pore sizes will give a greater adsorption capacity
     for large molecules.

     Adsorptivity increases as the solubility of the solute
     decreases.  For hydrocarbons, adsorption increases with
     molecular weight.

     Adsorption capacity will decrease with increasing
     temperature.

     For solutes with ionizable groups, maximum adsorption
     will be achieved at a pH corresponding to the minimum
     ionization.

The rate of adsorption is also an important consideration.  For
example, while capacity is increased with the adsorption of higher
molecular weight hydrocarbons, the rate of adsorption is decreased.
Similarly, while temperature increases will decrease the capacity,
they may increase the rate of removal of solute from solution.

Carbon adsorption requires pretreatment to remove excess suspended
solids, oils, and greases.  Suspended solids in the influent should
be less than 50 ppm to minimize backwash requirements; a downflow
carbon bed can handle much higher levels (up to 2000 ppm), but
frequent backwashing is required.  Backwashing more than two or
three times a day is not desirable; at 50 ppm suspended solids, one
                            VII-201

-------
backwash will suffice.  Oil and grease should  be  less  than about
10 ppm.  A high level of dissolved  inorganic material  in  the
effluent may cause problems with thermal carbon reactivation
(i.e., scaling and loss of activity) unless appropriate preventive
steps are taken; such steps might include pH control,  softening,
or the use of an acid waste on the  carbon prior to  reactivation.

Activated carbon is available in both powdered and  granular form.
The equipment necessary for a granular activated  carbon adsorption
treatment system consists of the following:  a preliminary clarifi-
cation or filtration unit to remove the bulk of suspended  solids;
two or three adsorption columns packed with activated  carbon
similar to the one shown in Figure  7-95; a holding  tank located
between the adsorbers; and liquid transfer pumps.   Unless  a reacti-
vation service is utilized, a furnace and associated quench tanks,
spent carbon tank, and reactivated  carbon tank are  necessary for
reactivation.

Powdered carbon is less expensive per unit weight than granular
carbon and may have slightly higher adsorption capacity but it
does have some drawbacks.  For example, it is more  difficult to
regnerate; it is more difficult to  handle (settling characteris-
tics may be poor); and larger amounts may be required  than for
granular systems in order to obtain good contact.   One innovative
powdered carbon system uses wet oxidation for regeneration instead
of fluidized bed incineration.  This technique has  been applied
mainly to municipal treatment but can be used in  industrial  systems,

The necessary equipment for a two stage powdered  carbon unit is
as follows:  four flash mixers, two sedimentation units, two surge
tanks, one polyelectrolyte feed tank, one dual media filter,  one
filter for dewatering spent carbon, one carbon wetting tank,  and
a furnace for regeneration of spent carbon.

Thermal regeneration, which destroys adsorbates,  is economical
if carbon usage is above roughly 454 kg/day (1000 Ibs/day).
Reactivation is carried out in a multiple hearth  furnace or  a
rotary kiln at temperatures from 870°C to 988°C.  Required  resi-
dence times are of the order of 30 minutes.  With proper control,
the carbon may be returned to its original activity; carbon  losses
will be in the range of 4-9% and must be made up with fresh  carbon.
Chemical regneration may be used if only one solute is present
which can dissolve off the carbon.  This allows material recovery.
Disposal of the carbon may be required if use is  less than  approxi-
mately 454 kg/day (1000 Ibs/day) and/or a hazardous component makes
regeneration dangerous.

A new type of carbonaceous adsorbent is made by pyrolizing  ion
exchange resins.  These spherical adsorbents appear to have  the
best characteristics of adsorbent resins and activated carbon.
                             VII-202

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WASTE WATER
  INFLUENT
 DISTRIBUTOR
 WASH WATER
                                               REPLACEMENT  CARBON
                                                    SURFACE  WASH
                                                       MANIFOLD
   BACKWASH
                                                 SUPPORT  PLATE
                        FIGURE 7-95
          ACTIVATED CARBON ADSORPTION COLUMN
                             VII-203

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They have a greater physical strength, attrition  resistance,  and
regeneration flexibility than either activated  carbon  or  polymer-
ic resins.  One type is particularly suited  for halogenated or-
ganics and has greater capacity than selected carbons  for com-
pounds such as 2-chloroethyl ether, bromodichloromethane, chloro-
form, and dieldrin.  Another type  (based on  a different polymeric
resin) is best suited for removing aromatics and  unsaturated  hy-
drocarbons.  A third type has a particularly high capacity (46
mg/1 or 46.45 kg/cu m (2.9 Ib/cu ft) at 2000 mg/1)  for phenol  and
other relatively polar organic molecules.  These  adsorbents are
commercially available but have not yet been proven  in large
scale operation.

Application and Performance

The principle liquid-phase applications of activated carbon adsorp-
tion include sugar decolorization; municipal water purification;
purifications of fats, oils, foods, beverages and Pharmaceuticals;
and industrial/municipal wastewater treatment.  Potentially,  it
is almost universally applicable because trace  organics are found
in the wastewater of almost every industrial plant.

Carbon adsorption, when applied to well-treated secondary effluent,
is capable of reducing COD to less than 10 mg/1 and BOD to under
2 mg/1.  Removal efficiencies may be in the range of 30%  to 90%
and vary with flow variations and different bed loadings.  Carbon
loadings in tertiary treatment plants fall within the range of
0.25 to 0.87 kg of COD removed per kg of carbon,  and if the columns
are operated downflow, over 90% suspended solids  reduction may  be
achieved.

Quite frequently, segregated industrial waste streams are  treated
with activated carbon.  The contaminants removed  include  BOD, TOC,
phenol, color, cresol, polyesters, polynitrophenol, toluene,
p-nitrophenol, p-chlorobenzene, chlorophenols,  insecticides,
cyanides and other chemicals, mostly organic.   The flows  being
treated are generally small in comparison with  tertiary systems
(less than 75,700 liters/day [20,000 gpd]).  Thermal reactivation
of the carbon does not become common until flows  are above
227,100 liters/day (60,000 gpd).  Some installations reactivate
their carbon chemically and the adsorbate is recovered.   Recover-
able adsorbates are known to include phenol, acetic acid, p-nitro-
phenol, p-chlorobenzene, p-cresol, and ethylene diamine-  Carbon
loadings approach one kg COD removal per kg carbon in installations
where the adsorbates are easily adsorbed and present in relatively
high concentrations.  In other cases, where influent concentrations
are lower and where the adsorbates are not readily adsorbed, much
lower loadings will result.  For example,  it was  determined that
brine wastewaters containing 150-750 ppm phenol and 1500-1800 ppm
acetic acid could be reduced to about 1 ppm phenol and 100-200 ppm
acetic acid with phenol loadings in the range of  0.09-0.16 kg per
kg and acetic acid loadings in the range of 0.04-0.06 kg  per kg.
                            VI1-204

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From metal finishing, loadings for cyanide removal have  been  found
to be on the order of 0.01 kg for influent concentrations  around
100 ppm.  Loadings for removal of hexavalent chromium have been
shown to be HS high as 0.07 kg/kg carbon at 100 ppm and  0.14  kg/kg
carbon at 1000 ppm.

EPA isotherm tests have indicated that activated carbon  is very
effective in adsorbing 65 percent of the organic priority  pollutants
and reasonably effective for another 22 percent.  Specifically, for
the organics of particular interest, activated carbon was  very
effective in removing 2,4-dimethylphenol, fluoranthene,  isoohorone,
naphthalene, all phthalates, and phenanthrene.  It was reasonably
effective on 1,1,1-trichloroethane , 1,1-dichloroethane,  phenol,
and toluene.  Table 7-36 summarizes the treatability effectiveness
for most of the organic priority pollutants by activated carbon
as compiled by EPA.  Table 7-37 summarizes classes of organic
compound together with examples of organics that are readily
adsorbed on carbon.

Samples were taken of influent and effluent streams around the
carbon adsorption unit at Plant ID 38040.  The results of  this
sampling are presented below.

                              Day 1               Day 2

Parameter                Influent  Effluent  Influent  Effluent

Oil and Grease           4.1       3.3       41.0      2.0
BOD                      58.0       *        53.0      8.0
TOC                      93.9      87.7      108.0     77.5
TSS                      14.0      11.0      1.0       9.0
TTO                      1.04      0.29      1.34      0.43

* Lab analysis experienced interference

Advantages and Limitations

The major benefits of carbon treatment include applicability  to a
wide variety of organics, with high removal efficiency.  Inorganics
such as cyanide, chromium, and mercury are also removed effectively.
Variations in concentration and flow rate are well tolerated.  The
system is compact, and recovery of adsorbed materials is sometimes
practical.  However,  destruction of adsorbed compounds often
occurs during thermal regeneration.  If carbon cannot be thermally
desorbed, it must be  disposed of along with any adsorbed pollutants.
When thermal regeneration is utilized, capital and operating  costs
are relatively high.   Cost surveys show that thermal regeneration
is generally economical when carbon usage exceeds about  454 kg/day
(1,000/lb-day).   Carbon cannot remove low molecular weight or
highly soluble  organics.   It also has a low tolerance for  suspended
solids, which must be removed to at least 50 ppm in the  influent
water.
                            VII-205

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                                            TABLE  7-36

               TREATABILITY RATING OF PRIORITY POLLUTANTS UTILIZING CARBON ADSORPTION
Priority Pollutant                 *Removal Rating

1.  acenaphthene                        H
2.  acrolein                            L
3.  acrylonitrile                       L
4.  benzene                             M
5.  benzidine                           H
6.  carbon tetrachloride                M
    (tetrachlorome thane)
7.  chlorobenzene                       H
8.  1,2,4-trichlorobenzene              H
9.  hexachlorobenzene                   H
10. 1,2-dichloroethane                  M
11. 1,1,1-trichloroethane               M
12. hexachloroethane                    H
13. 1,1-dichloroethane                  M
14. 1,1,2-trichloroethane               M
15. 1,1,2,2-tetrachloroethane           H
16. chloroethane                        L
17. bis(chloromethyl)ether
18. bis(2-chloroethyl)ether             M
19. 2-chloroethyl vinyl ether           L
    (mixed)
20. 2-chloronaphthalene                 H
21. 2,4,6-trichlorophenol               H
22. parachlorometa cresol               H
23. chloroform (trichloromethane)       L
24. 2-chlorophenol                      H
25. 1,2-dichlorobenzene                 H
26. 1,3-dichlorobenzene                 H
27. 1,4-dichlorobenzene                 H
28. 3,3'-dichlorobenzidine              H
29. 1,1-dichloroethylene                L
30. 1,2-trans-dichloroethylene          L
31. 2,4-dichlorophenol                  H
32. 1,2-dichloropropane                 M
33. 1,2-dichloropropylene               M
    (1,3,-dichloropropene)
34. 2,4-dimethylphenol                  H
35. 2,4-dinitrotoluene                  H
36. 2,6-dinitrotoluene                  H
37. 1,2-diphenylhydrazine               H
38. ethylbenzene                        M
39. fluoranthene                        H
40. 4-chlorophenyl phenyl ether         H
41. 4-bromophenyl phenyl ether          H
42. bis(2-chloroisopropyl)ether         M
43. bis(2-chloroethoxy)methane          M
44. methylene chloride                  L
    (dichlorome thane)
45. methyl chloride (chloromethane)     L
46. methyl bromide (bromomethane)       L
47. bromoform (tribromomethane)         H
48. dichlorobromomethane                M
Priority Pollutant
                                                                                           *Rerooval  Rating
49.  trichlorofluoromethane        M
50.  dichlorodifluoromethane       L
51.  chlorodibromomethane          M
52.  hexachlorobutadiene           H
53.  hexachlorocyclopentadiene     H
54.  isophorone                    H
55.  naphthalene                   H
56.  nitrobenzene                  H
57.  2-nitrophenol                 H
58.  4-nitrophenol                 H
59.  2,4-dinitrophenol             H
60.  4,6-dinitro-o-cresol          H
61.  N-nitrosodijnethylamine        M
62.  N-nitrosodiphenylamine        H
63.  N-nitrosodi-n-propylamine     M
64.  pentachlorophenol             H
65.  phenol                        M
66.  bis(2-ethylhexyl)phthalate    H
67.  butyl benzyl phthalate        H
68.  di-n-butyl phthalate          H
69.  di-n-octyl phthalate          H
70.  diethyl phthalate             H
71.  dimethyl phthalate            H
72.  1,2-benzanthracene (benzo     H
     (a)anthracene)
73.  benzo(a)pyrene (3,4-benzo-    H
     pyrene)
74.  3,4-benzofluoranthene         H
     (benzo(b)fluoranthene)
75.  11,12-benzofluoranthene       H
     (benzo(k)fluoranthene)
76.  chrysene                      H
77.  acenaphthyler.o                K
78.  anthracene                    H
79.  1,12-benzoperylene (benzo     H
     (ghi)-perylene)
80.  fluorene                      H
81.  phenanthrene                  H
82.  1,2,5,6-dibenzathracene       H
     (dibenzo (a,h) anthracene)
83.  indeno (1,2,3-cd) pyrene      H
     (2,3-o-phenylene pyrene)
84.  pyrene                        -
85.  tetrachloroethylene           M
86.  toluene                       M
87.  trichloroethylene             L
88.  vinyl chloride                L
     (chloroethylene)
106. PCB-1242 (Arochlor 1242)      H
107. PCB-1254 (Arochlor 1254)      H
108. PCB-1221 (Arochlor 1221)      H
109. PCB-1332 (Arochlor 1232)      H
110. PCB-1248 (Arochlor 1248)      H
111. PCB-1260 (Arochlor 1260)      H
112. PCB-1016 (Arochlor 1016)      H
*  NOTE:  Explanation of Removal Ratings

Category H (high removal)
     adsorbs at levels _> io° m9/g carbon at C  = 10 mg/1
     adsorbs at levels j> 100 nig/g carbon at C* < 1.0 mg/1

Category M (moderate removal)
     adsorbs at levels _>. 1°° mg/g carbon at C. = 10 mg/1
     adsorbs at levels _< 100 ing/g carbon at C* < 1.0 mg/1

Category L (low removal)
     adsorbs at levels < 1UU nig/g carbon at Cf   10 mg/1
     adsorbs at levels < 10 mg/g carton at Cf < 1.0 rag/1

Cj = final concentrations of priority pollutant at equilibrium
                                                    VII-206

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                                   Table 7-37
                Classes of Organic Compounds Adsorbed on Carbon
Organic Chemical Class

Aromatic Hydrocarbons

Bolynuclear Aromatics


Chlorinated Aromatics



Phenolics


Chlorinated Phenolics
*High Molecular Weight Aliphatic and
 Branch Chain Hydrocarbons

Chlorinated Aliphatic Hydrocarbons
*High Molecular Weight Aliphatic Acids
 and Aromatic Acids

*High Molecular Weight Aliphatic Amines
 and Aromatic Amines

*High Molecular Weight Ketones, Esters,
 Ethers & Alcohols

Surfactants

Soluble Organic Dyes
Examples of Chemical Class

benzene, toluene, xylene

naphthalene, anthracene
biphenyls

chlorobenzene, polychlorinated
biphenyls, aldrin, endrin,
toxaphene, DDT

phenol, cresol, cesorcenol
and polyphenyls

trichlorophenol, pentachloro-
phenol

gasoline, kerosine
1,1,1-Trichloroethane, tri-
chloroethylene, carbon tetra-
chlor ide, perchloroethylene

tar acids, benzoic acid
aniline, toluene diamine


hydroquinone, polyethylene
glycol

alky! benzene -sulfonates

methylene blue, Indigo carmine
* High Molecular Weight includes compounds in the range of
  4 to 20 carbon atoms
                                   VII-207

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Operational Factors

Reliability:  This system should be very reliable assuming up-
stream protection and proper operation and maintenance procedures.

Maintainability;  This system requires periodic regeneration or
replacement of spent carbon and is dependent upon raw waste load
and process efficiency.

Solid Waste Aspects;  Solid waste from this process is contaminated
activated carbon that requires disposal.  If the carbon undergoes
regeneration, the solid waste problem is reduced because of much
less frequent replacement.

Demonstration Status

Carbon adsorption systems have been demonstrated to be practical
and economical for the reduction of COD, BOD and related parameters
in secondary municipal and industrial wastewaters; for the removal
of toxic or refractory organics from isolated industrial waste-
waters; for the removal and recovery of certain organics from
wastewaters; and for the removal, at times with recovery, of se-
lected inorganic chemicals from aqueous wastes.  Carbon adsorption
must be considered a viable and economic process for organic waste
streams containing up to 1-5% of refractory or toxic organics; its
applicability for removal of inorganics such as metals, although
demonstrated in a few cases, is probably much more limited.

Carbon adsorption is being used in 10 plants in the present Metal
Finishihg Category data base and these are identified in Table 7-38.

                         Table 7-38
     Metal Finishing Plants Employing Carbon Adsorption

                    04236          18538
                    04690          19120
                    12065          25033
                    14062          31044
                    17061          38040

Segregated Oily Waste System Performance - Option 3

In order to calculate the effluent concentrations discharged for the
Option 3 oily waste treatment system, separate performance efficien-
cies were calculated for removal of oils and toxic organics by means
of carbon adsorption and reverse osmosis.  These removal efficiencies
ace summarized in Table 7-39.
                                VTI-208

-------
                             TABLE 7-39
              OPTION 3 OILY WASTE REMOVAL EFFICIENCIES

                Carbon Adsorption              Reverse Osmosis

                          Removal                         Removal
              In    Out   Efficiency(%)       In    Out   Efficiency(%)
Oil & Grease   22.6  2.65    88.3              86.0  17.9     79.2
TTO           1.19  0.36    69.7              2.88  0.80     72.2

The lower of  each of these efficiencies were then applied  to the
effluents from the Option 2 treatment system to establish  the  Option
3 mean effluent concentrations that are listed in Table 7-40.

                            TABLE 7-40
              OPTION 3 MKAM tft'VLUSrt r CONCENTRATIONS

                           Option 2        Removal         Option  3
Parameter              Mean Effluent    Efficiency(%)  Mean  Effluent

Oil & Grease                1.90            79.2            0.40
Total Toxic Organics       0.13            69.7            0.04

The Option 3  segregated oily waste performance limitations are
summarized as follows:

           Segregated Oily Waste Performance - Option ^3

                                   Oils & Grease           TTO

Mean Effluent Concentration             0.40               0.04
Variability Factor                      2.9/1.3            2.9/1.3
Daily Maximum Concentration             1.16               0.12
30-day Average Concentration            1.0*               0.05

*1 mg/1 is considered the minimum detectable limit for oil.

Summary of Waste Treatment Option Limitations

The effluent  limitation concentrations for the oily waste  treatment
options are summarized in mg/1 in Table 7-41 and a complete  summary
of the effluent limitation concentrations for the Metal Finishing
Category is presented in Table 7-42.
                             VII-209

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                          TABLE 7-41
       COMBINED WASTEWATER - COMMON METALS SUBCATEGORY
Parameter

Oil & Grease
Total Toxic Organics
             Option  1
    Daily Max.   30-day Avg
          34.5
          0.12
  15.5
  0.05
             Option 2
   Daily Max.   30-day Avg.

         20.6       9.20
         (single  option)
          SEGREGATED WASTE  -  OILY WASTE SUBCATEGORY
Option 1
Daily
Max .
69.0
3.07
30-day
Avg .
30.9
1.38
Opti
Daily
Max.
5.51
0.38
on 2
30-day
Avg .
2.47
0.17
Parameter

Oil & Grease
Total Toxic Pollutants
                          TABLE  7-42
    SUMMARY OF EFFLUENT  LIMITATION CONCENTRATIONS (mg/1)
Parameter

TSS
Cadmium
Chromium
Copper
Iron
Lead
Nickel
Zinc
Flourides
Oil & Grease
COMMON METALS SUBCATEGORY

             Option 1
           Daily  30-day
           Max.   Avg.
           Option 2
         Daily  30-day
         Max.   Avg.
           51.6
           0.04
           2.23
           2.61
           2.31
           0.15
           2.73
           1.65
           44.4
           31.9
23.1
0.02
0.80
1.06
1.04
0.07
1.23
0.72
19.9
14.3
33.6
0.03
1.24
1.18
0.75
0.10
1.60
0.74
13.8
20.6
                    SINGLE OPTION  LIMITATIONS
Parameter

Silver
Hexavalent Chromium
Cyanide, Total
Cyanide, Amenable
Total Toxic Organics
           Daily Maximum
               0.28
               0.17
               6.00
               1.95
               0.12
15.1
.015
0.45
0.48
0.33
0.04
0.72
0.32
6.19
9.20
                                              Option 3
                                            Daily  30-day
                                            Max.   Avg.
                                            1.16
                                            0.12
                                 1.0
                                 0.05
   Option 3
Daily  30-day
Max.   Avg.

33.6   15.1
Background
1.24   0.45
1.18   0.39
0.75   0.33
Background
1.60   0.63
0.74   0.32
13.8   6.19
20.6   9.20
                30-day Average

                    0.13
                    .048
                    1.80
                    0.58
                    0.05
                               VI1-210

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ALTERNATIVE OILY WASTE TREATMENT TECHNOLOGIES
In addition to the treatment methods presented for  the Option  1,  2,
and 3 systems, there are several other alternative  technologies  that
are applicable for the treatment of oily wastewater.  The  following
paragraphs describe these technologies:  coalescing,  flotation,  cen-
trifugation, integrated adsorption, resin adsorption, ozonation,
chemical oxidation, aerobic decomposition, and thermal emulsion
breaking.

COALESCING

Description of the Process

The basic  principle of coalescing involves the preferential wetting
of a coalascing medium by oil droplets which accumulate on the medium,
and then rise to the surface of the solution.  The  most important  re-
quirements for coalescing media are wettability for oil and large  sur-
face area.

Coalescing stages may be integrated with a wide variety of gravity
oil separation devices, and some systems may incorporate several
coalescing stages.  In general, the provision of preliminary oil
skimming treatment is desirable to avoid overloading  the coalescer.
One commercially marketed system for oily waste treatment  (See
Figure 7-96) combines coalescing with gravity separation.  In  this
unit, the  oily waste enters the separator where the large droplets
immediately move to the top surface of the separator  because of  the
specific gravity differential.  The smaller droplets  enter the cor-
rugated plate area where laminar flow produces coalescing of the oil
droplets.   The oil droplets deposit on the surface  of the plants and
stream upward through weep holes in the plates to the surface, where
adjustable skimmers remove the oil.  Heavy solids are deposited  in
the entrance chamber before the oily wastewater enters the plate area.

Application and Performance

Coalescing is used in the Metal Finishing Category  for treatment of
oily wastes.  The analysis results of samples taken before and after
a coalescing gravity separator at Plant ID 38217 are  shown below.
                    Day 1
Parameter      Raw       Effluent

Oil & Grease   8320.     490.
TOC            923.      1050.
BOD            2830.     2950.
TSS            637.      575.
TTO            1.65      1.18
     Day 2
Raw

4240.

1980.
1610.
4.11
Effluent

619.
535.
1530.
620.
0.66
                             VI1-211

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s
M
I
                   INFLUENT
                   OIL-WATER
                   MIXTURE
                   OIL OUTLET
                     DRAIN
OIL SKIMMER
              OIL
SEPARATED OIL  SKIMMER   OIL DAM
                                       INLET WEIR
                                          \
                                        COALESCING
                                        PLATE ASSEMBLY
                                                                                          OUTLET
                                                                                          WEIR
                                                              CLEAN
                                                              WATER
                                                              EFFLUENT
                                                                                            DRAIN
                                                  FIGURE 7-96

                                         COALESCING GRAVITY SEPARATOR

-------
Advantages and Limitations

Coalescing allows removal of oil droplets too finely dispersed  for
conventional gravity separation/skimming technology.   It can  also
significantly reduce the residence times (and therefore separator
volumes)  required to achieve separation of oil from some wastes.
Because of its simplicity, coalescing oil separators provide  gen-
erally high reliability and low capital and operating  costs.
Coalescing is not generally effective in removing soluble or
chemicall stabilized emulsified oils.  To avoid plugging, coales-
cers must be protected by pretreatment from very high  concentra-
tions of free oil and grease and suspended solids.  Frequent  re-
placement of prefilters may be necessary when raw waste oil con-
centrations are high.

Operational Factors

Reliability;  Coalescing is inherently highly reliable because  there
are no moving parts, and the coalescing substrate is inert in the
process and therefore not subject to frequent regeneration or re-
placement requirements.  Large loads or inadequate prior treatment,
however, may result in plugging or bypassing of coalescing stages.

Maintainability;   Maintenance requirements are generally limited to
replacement of the coalescing medium on an infrequent  basis.

Solid Wastes Aspects

No appreciable solid waste is generated by this process, but when
coalescing occurs in a gravity separator, the normal solids accum-
ulation is experienced.

Demonstration Status

Coalescing has been fully demonstrated in the Metal Finishing Cate-
gory and in other industries that generate oily wastewater.  Coales-
cers are used at  3 facilities in the prosent data base:  Plant  ID'S
14001, 20173, and 38217.

FLOTATION

Floation, as was  explained in the "Treatment of Common Metals Wastes"
section,  is the process of causing particles such as oil or metal
hydroxides to float to the surface of a tank where they can be  con-
centrated and removed.  This is brought about by releasing gas  bub-
bles which attach themselves to the particles, increasing their
buoyancy, causing them to rise to the surface and float.  Flota-
tion units are commonly used in industrial operations  to remove
free and  emulsified oils and grease.  For these applications  in the
                              VI1-213

-------
Metal Finishing Category, the flotation  technique  commonly referred
to as dissolved air flotation (DAF)  is employed.   Dissolved air
flotation utilizes the emulsion breaking  techniques  that  were pre-
viously discussed and in addition uses the bubbles of  dissolved air
to assist in the agglomeration of the oily droplets  and  to provide
increased buoyancy for raising the oily  droplets to  the  surface.
A typical dissolved air flotation system  is  shown  in Figure 7-97.

Application and Performance

The performance of a flotation system depends  upon having suffici-
ent air bubbles present to float essentially all of  the  suspended
solids  An insufficient quantity of  air will result  in only partial
flotation of the solids, and excessive air will yield  no  improvement,
The performance of a flotation unit  in terms of effluent  quality
and solids concentration in the float can be related to an air/
solids ratio.  The shape of the curve obtained will  vary  with the
nature of the solids in the feed.

The results of sampling done at Plant ID  33692 are presented  below.

                         Day 1                     Day  2

Parameter           Influent    Effluent     Influent     Effluent

Oil & Grease        412.        108.         65.8         28.9
TOG                 3000.       132.         98.          86.
BOD                 130.        78.          31.          24.
TSS                 416.        210.         166.         103.

Advantages and Limitations

The use of dissolved air for oily waste flotation subsequent  to
emulsion breaking can provide better performance in  shorter reten-
tion times (and therefore smaller flotation tanks) than with  emul-
sion breaking without flotation.  A  small reduction  in the quanti-
ty of chemical for emulsion breaking is also possible.  Dissolved
air flotation units have been used successfully, in  conjunction
with further subsequent processes, to reclaim oils for direct  reuse
and/or use as power plant fuels in the Metal Finishing Category.

Operational Factors

Reliability;  Dissolved air flotation can be highly  reliable  de-
pending only upon the reliability of the recycle pump, air regu-
lator, and air jets.

Maintainability;  Routine periodic maintenance of the recycle
pump, regulator, air jets, tank, and lines is required.
                             VI1-214

-------
                               Oil
 Chemical Addition
$
M
To Disposal   Sludge  Line  (If  Req'd)
              1
                Air  Jets
              Influent
              Pressure
             Regulator
                   Pressure
                     Tank
                                                      FLOTATION
                                                        TANK
                                                                     Recycle
                                                       Effluent
                                                                                 Optional  Source
                                        Centrifugal  Pump
                                          FIGURE 7-97

                              TYPICAL DISOLVED AIR FLOTATION SYSTEM

-------
Solid Waste Aspects

If preceded by a settling device, very little solid waste  is  gen-
erated by this process unless large quantities of salts are used.

Demonstration Status

Flotation is used in 29 facilities in the present data base and
these are identified in Table 7-21.

CENTRIFUGATION

Centrifugation is the process of applying a centrifugal force to
cause the separation of materials.  This force is many times  the
force of gravity so it allows for solids separation in a much
shorter time than that required by settling.  When a suspension
is centrifuged, the components of the solution with the greatest
specific gravity accumulate at the farthest distance from  the
axis of the centrifuge and those with the least specific gravity
are located nearest the axis.  So when oily wastes containing
suspended solids are centrifuged, the solids portion collects
at the outside of the centrifuge, the oil forms the innermost
layer, and the water portion is sandwiched in between.  The
different layers that are formed can then be collected separately.
Centrifuges are currently available that have been specifically
designed to separate either oil/water mixtures or oil/solids/water
mixtures.  Centrifugation equipment is in use as a pretreatment
technique to separate oil/water mixtures prior to further  waste-
water treatment.

The performance of the centrifuge at plant ID 19462, which employs
Centrifugation to lower the oil concentration of the wastewater
prior to further oil removal by ultrafiltration, was established
by sampling the influent and effluent streams.  The results are
presented below.

                         Day 1                  Day 2

Parameter           In        Out       In             Out

Oil and Grease      373,280   3402      14,639         1102
TSS                 6866      1266      8938           1154

A detailed discussion on the various types of centrifuges  is pre-
sented under the heading "Treatment of Sludges".

Centrifugation is used on oily wastes by 5 plants in the present
data base:  Plant ID'S 06019, 11184, 14062, 19462, and 30166.
                               VII-216

-------
INTEGRATED ADSORPTION

Description of the Process

The integrated adsorption process is designed for disposal of mater-
ials indilute aqueous emulsion, such as oils and paints.  The active
agent is any of several aluminum silicate-based formulations in pow-
der form.  This material is added to the wastewater, and  the mixture
is agitated for six minutes.  During this period, the powder adsorbs
the emulsified materials.  Next, the solid material  is allowed to
settle for two minutes, and the water phase is then  decanted through
a disposable belt filter, leaving any unsettled solids onthe filter.
Finally, the sludge phase is ejected on the disposable belt filter,
where it is partially dewatered.  Both the belt and  the material
retained on it feed into a disposal container.  The  filtered water
is collected for reuse or discharge.

 The integrated adsorption process is available as a commercial sys-
tem.  Equipment consists of a reagent feed hopper, an associated
automatic feed device, a wastewater feed pump, a reaction vessel,
a high-speed turbine mixer, a disposable belt, a band filter, a
clean water pump, a clean water tank, and associated controls.

Advantages and Limitations

The integrated adsorption system does not add anything to the
processed water, the pH and salinity of which are unaffected.
The system is designed for automatic operation, and  the sludge
is leachresistant because of the strong bonding of the adsorbed
materials.  The system obviates th • need for other chemical treat-
ment or physical separation, but it does entail both capital and
operating expense.

Demonstration Status

The integreated adsorption system consistently removes greater than
99 percent of the paints, detergents, and emulsified oils in the
feed stream.  The sludge is 20 to 40 percent solids, and  is strongly
resistant to leaching.

The system is employed for treating paint booth water and emulsi-
fied oils by a leading European auto maker, among others.  There
are more than 100 units presently in service.

RESIN ADSORPTION

Adsorption of trace oryanics on synthetic resins is  similar to
adsorption on activated carbon.  The basic materials are different
and the means of regeneration are different.  A potential advantage
is that resins are more easily tailored for removal of specific pol-
lutants .
                             VII-217

-------
The resins are generally microporuous styrene-divinylbenzenes,  acry-
lic esters, or phenol-formaldehydes.  Each type may  be  produced in a
range of densities, void volumes, bulk densities,  surface  areas,
and pore sizes.  The formaldehyde resins are granular,  and the  others
are in the form of beads.

Adsorptive resins are in limited commercial use for  removal  of  pri-
ority and other organics.  There are existing operations for removal
of phenols in two plants (one in Indiana and the other  at  a  coal
liquefaction plant in West Virginia), for removal  of  fats  at a  food
processing plant, and for removal of organic dyes  at  several plants.
Pilot plant operations have been designed for removal of trinitro-
toluene, 2 ,4-dinitrotoluene, cyclomethylenetrinitramine, cyclotetra-
methylenetetranitramine, Endrin, other pesticides, laboratory car-
cinogens (unspecified), 2,4-dichlorophenol, ethylene  dichloride and
vinyl chloride.  In a non-industrial application,  organic  carbon re-
moval efficiency decreased from 58 percent to 40 percent during a
throughput of 5,000 bed volumes, with an input concentration of about
6 mg/1.

Regeneration of the resins is done chemically, while  regeneration
of activated carbon is thermal.  The chemical may  be  an inorganic
acid, base, or salt, or an organic solvent such as acetone.

OZONATION

Ozone is effective in the treatment of phenols.  It  is  about twice
as powerful as'hydrogen peroxide and is not as selective;  thus  it
oxidizes a wider range of material.  For low concentration phenolic
wastes, the usual practice is to oxidize the phenolic compound  to
intermediate organic compounds that are toxic but  readily  biodegrd-
able.  For this application, ozone requirements are  in  the range of
1.5 to 2.5 parts of ozone per part of phenol.  As  the concentration
decreases, the relative amount of ozone needed increases.  If other
material with COD is present, the ozone requirement will be  still
greater.  When pH values of 11.5 to 11.8 are maintained, this range
appears to result in selective or preferential oxidation of  phenol
over other substances.

For concentrated or intermediate level phenolic wastes  chemical
oxidation by ozone may not be economical as a primary treatment
system; however, it is useful as a polishing process  following
a biological system.  In treating phenolic refinery wastes,  ozone
is used as tertiary treatment to produce final effluents as  low
as 3 ug/1 phenol.

Several manufacturers have begun using ozone for the  treatment  of
phenolic industrial wastewaters.  They are listed  and briefly
described below:
                             VI1-218

-------
     A.    An oil refinery in Canada treats waste effluent of
          1,514,000 liters/day (400,000 gallons/day) with the
          phenol concentration averaging 50 mg/1.

          Pretreatment consists of pre-aeration and a biologi-
          cal trickling filter.  Ozonation is the  final treat-
          ment step and utilization is 86 kg/day (190 pounds/
          day).   This treatment results in an effluent of less
          than 0.012 mg/1 residual phenol.

     B.    A manufacturer of a thermoplastic resin  in New York
          treats a phenolic effluent by biological oxidation.
          Further treatment was necessary to meet  state stan-
          dards.  The effluent had a high COD of about 1500
          mg/1 which competed with the phenol for  ozone;
          therefore a large ozone dosage level, 300 ppm, was
          required to reach the desired phenol effluent con-
          centration.  At a flow rate of 946,250 liters/day
          (0.25  MGD), a total of 283.5 kg (625 pounds) of
          ozone  was required daily-  The air feed  generating
          equipment represents a capital investment of $220,000
          and requires daily operating expenditures of $98.43
          including electrical costs of 1.5jzf/kwh.   Concurrent
          with phenol removal, 30 percent of the color, 29
          percent of the turbidity and 17 percent  of the COD
          were removed.

     C.    Study  of various coke plant wastes shows that various
          ozone  requirements are necessary to oxidize the phenol
          The results are displayed in Table 7-43.  The great
          variation in the ozone-to-phenol ratios  of samples
          from different sources illustrates the differences
          in the composition of the wastes.

                           Table 7-43
            Ozone Requirements for Phenol Oxidation
Source
Coke Plant A
H     ii     B
II II
II II
II II
II II
Chemical
Refinery
D
E
F
G
H
.. A*
A
Initial
Phenols
 mg/1

 1240
  800
  330
  140
  127
  102
   51
   38
  290
  605
 Ozone
 Demand
  mg/1

  2500
  1200
  1700
   950
   550
   900
  1000
   700
   400
11,000
Ozone/
Phenol
ratio

 2.0
 1.5
 5.2
 6.8
 4.3
 8.8
  20
  18
 1.4
18.0
Residual
Phenols
 mg/1

 1.2
 0.6
 1.0
 1.0
 0.2
 0.0
 0.4
 0.1
 0.3
 2.5
*This  plant  effluent  contained 2,4-dichlorophenol and the
 results  are expressed  as  such.
                              VII-219

-------
Ozone has been investigated for the treatment of photographic
wastes, and research and development studies have indicated  that
it is capable of effectively treating compounds that are expected
to be found in waste streams from this industry.  There are  not,
however, any installations in current operation.  This process has
been utilized successfully to treat photoprocessing waste, and it
is beginning to gain acceptance as a practical and economic  form
of treatment.

Ozone is also effective in treating wastewaters containing other
organics and organo-metal complexes.  In organo-metal complexes the
metals can be released and then precipitated.  One kilogram  of COD
should consume three kilograms of ozone and yield two kilograms of
molecular oxygen.

CHEMICAL OXIDATION

Chemical oxidation can be effective in destroying the priority
organic compounds.  In particular, oxidation by ozone, by ozone
with ultraviolet radiation, by hydrogen peroxide, and possibly
by electrolytic oxidation.  Oxidation by chlorine is more likely
to generate priority organics than to destroy them.

These oxidation techniques are used industrially primarily for
cyanide destruction.  They are therefore discussed in detail
under the general heading of "Treatment of Cyanide Wastes",
earlier in this section.  Where information is available, these
discussions include consideration of ability to destroy priority
organics.

AEROBIC DECOMPOSITION

Definition of the Process

Aerobic decomposition is the biochemically actuated decomposition
or digestion of organic materials in the presence of oxygen.  The
chemical agents effecting the decomposition are microorganism
secretions termed enzymes.  The principal products in a properly
controlled aerobic decomposition are carbon dioxide and water.
Aerobic decomposition is used mainly in the treatment of organic
chemicals and lubricants used in the film industry and such  other
industries that use organic lubricants.

Description of_ the Process

As a waste treatment aid, aerobic decomposition plays an important
role in the following organic waste treatment processes:
                              VI1-2 20

-------
     1.    Activated Sludge Process
     2.    Trickling Filter Process
     3.    Aerated Lagoon

The activated sludge process consists of the aeration of a biode-
gradable waste for a sufficient time to allow the formation of a
large mass of settleable solids.  These settleable solids are mas-
ses of living microorganisms and are termed activated sludge.

A schematic diagram of the basic process is shown as Figure 7-98.
The wastes enter the aeration tank after being mixed with return
sludge.   The microorganisms from the returned sludge aerobically
stabilize the organic mixture which then flows to a sedimentation
tank.  Sedimentation allows the activated sludge to flocculate
and to settle out, producing a clear effluent of low organic con-
tent.  A portion of the waste sludge is returned to the aeration
tank, thereby repeating the process.  Excess sludge is discharged
from the process for further treatment or disposal.

The trickling filter is basically a bed of stones or other suitable
material covered with slime over which organic wastes slowly flow.
A schematic cross section of a trickling filter is shown as Figure
7-99.  As wastewater passes through the filter, it diffuses into
the slimes where aerobic and anaerobic decomposition occurs.  Af-
ter primary sedimentation, the wastewater is introduced onto the
filter by a rotary distributor so designed that the wastes are dis-
charged at a uniform volume per unit of filter surface.  The waste
flows by gravity over the filter bed into an underdrain system.
The liquid is collected into a main effluent channel which flows
to a final sedimentation tank.  A schematic diagram of a single
stage trickling filter is shown as Figure 7-100.

An aerated lagoon is a large shallow pond to which raw waste is
added at one end or in the center and the treated effluent dis-
charged at the other end.  Aeration is accomplished by mechanical
aerators or diffusers in the wastewater.  Aerobic decomposition
is one of the factors involved in degradation of the organic mat-
ter and is carrried out by bacteria in a manner similar to acti-
vated sludge.  It is necessary to periodically dredge the oxida-
tion pond in order to maintain the proper ecological balance.

Application and Performance

Aerobic  decomposition can be applied to the treatment of oily
wastes from the Metal Finishing Category.

Advantages and Limitations

Advantages of aerobic decomposition include 1) low BOD concentra-
tions in supernatant liquor, 2) production of an odorless, humus-
                              VII-221

-------
   SETTLED
   WASTES
                     AERATION
                       RETURN SLUDGE
SECONDARY
 SEDIMEN-
  TATION
            EFFLUENT
                                                      WASTE EXCESS

                                                        SLUDGE
                        FIGURE 7-98

SCHEMATIC DIAGRAM OF A CONVENTIONAL ACTIVATED SLUDGE  SYSTEM
                             VII-222

-------
///\\\  //i>\
•  // \ \\/M\\\
C7
           C?
                       j
                       Stone media
                         6-10' depth
Vitrified clay underdrains

Reinforced concrete floor
                   FIGURE 7-99


       SCHEMATIC CROSS SECTION OF A TRICKLING FILTER
                      VII-223

-------
 RAW
SEWAGE
                      WASTE
                      SLUDGE
 PRIMARY
SEDIMENTA
   TION
SECONDARY
SEDIMENTA
   TION
TRICKLING
 FILTER
                               FIGURE  7-100
            SCHEMATIC  DIAGRAM  OF A SINGLE-STAGE TRICKLING FILTER
                                   VI1-224

-------
like, biologically stable end product with excellent dewatering
characteristics that can be easily disposed, 3) recovery of more
of the basic fertilizer values in the sludge, and 4) few opera-
tional problems and low initial cost.  The major disadvantages of
the aerobic decomposition process are 1) high operational cost
associated with supplying the required oxygen, and 2) sensitivity
of the bacterial population to small changes in the characteris-
tics of their environment.

Operational Factors

Reliability - Reliability can be high, assuming adequate tempera-
ture, pH, detention time, and oxygen content control.  Prior treat-
ment to eliminate substances toxic to the microorganisms affecting
decomposition may be necessary.  (In some cases, adaptation will
increase the tolerance level of the microorganisms for toxic sub-
stances) .

Maintainability;  Maintenance of the three main waste treatment
techniques employing aerobic decomposition is detailed in the fol-
lowing table:

     Process                            Maintenance

Activated Sludge    Periodic removal of excess sludge and skimming
                    of scum layer.

Trickling Filter    Periodic application of insecticides to reduce
                    the insect population and periodic chlorination
                    to reduce excess bacterial population.

Aerated Lagoon      Periodic dredging to remove excess sludge, and
                    periodic aeration to maintain the pond's aero-
                    bic character.

Solid Waste Aspects

Dewatering of digested sludge generated in the activated sludge pro-
cess may be desirable prior to contractor removal, incineration, or
disposal to landfill.

Demonstration Status

Aerobic digestion is a widely used unit process to reduce organic
content of wastewaters.  It is currently employed at 14 of the
plants in the data base and these are identified in Table 7-44.
                              VI1-225

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                         TABLE  7-44
   METAL FINISHING PLANTS EMPLOYING AEROBIC  DECOMPOSITION


               05050     11560     23041      33263
               06067     11179     30927      44050
               08172     13031     31050
               11050     14062     33050

THERMAL EMULSION BREAKING

Thermal emulsion breaking is usually a continuous process.   In most
cases, however, these systems are operated intermittently,  due to
the batch dump nature of most emulsified oily wastes.   The  emulsi-
fied raw waste is collected in  a holding tank until  sufficient volume
has accumulated to warrant operating the thermal emulsion breaking
system.  One such system is an  evaporation-distillation-decantation
apparatus which separates the spent emulsion  into distilled water,
oil and other floating particles, and sludge  (See Figure  7-101).
Initially, the raw waste flows  from the holding tank into the  main
conveyorized chamber.  Warm dry air is passed over a large  revolving
drum which is partially submerged in the emulsion.   Some  water evapor-
ates from the surface of the drum and is carried upward through a fil-
ter and a condensing unit.  The condensed water is discharged  and can
be reused as process makeup, while the air is reheated  and  returned
to the evaporation stage.  As the concentration of water  in the main
conveyorized chamber decreases, oil concentration increases and some
gravity separation occurs.  The oils and other emulsified wastes
which separate flow over a weir into a decanting chamber.   A rota-
ting drum skimmer picks up oil  from the surface of this chamber and
discharges it for possible reprocessing or contractor removal.  Mean-
while, oily water is being drawn from the bottom of  the decanting
chamber, reheated, and sent back into the main conveyorized chamber.
This aids in increasing the concentration of oil in  the main chamber
and the amount of oil which floats to the top.  Solids  which settle
out in the main chamber are removed by a conveyor belt.  This  con-
veyor, called a flight scraper, moves slowly so as not  to disturb
the settling action.  As with the use of acids for chemical emul-
sion breaking, thermal emulsion breaking is more commonly used  for
oil recovery than for oily waste removal.

Application and Performance

Emulsion breaking technology can be applied to the treatment of
emulsified oil/water mixtures in the Metal Finishing Category
wherever it is necessary to separate oils, fats, soaps, etc. from
wastewaters.
                              VII-226

-------
                           REHEATING
                           COIL
 MAKE UP TO
 OPERATING
 EMULSION SYSTEM
          AIR
          RECIRCULATION
          FAN
                                         CONDENSING
                                         UNIT
                                                       AIR ft
                                                       MOISTURE
WARM
DRY
AIR
                                                      SLUDGE
                                                      CONVEYOR
                                       DISTILLED
                                       WATER
           TRANSFER
           PUMP
                                                      SLUDGE
                                                      DISCHARGE
             DECANTING
              CHAMBER
                 MAIN CONVEYORIZEO
                ^	^CHAMBER
               cT
                                                     FROM SPENT
                                                   EMULSION TANK
OIL
DISCHARGE
                          TRANSFER
                          PUMP
                         FIGURE  7-101

                  THERMAL EMULSION BREAKER

                             VII-227

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The performance level using thermal emulsion breaking  is dependent
primarily on the characteristics of the raw waste and  proper main-
tenance and functioning of the system components.  Some emulsions
may contain volatile compounds which could escape with the distilled
water.  In systems where the water is recycled back to process, how-
ever, this problem is essentially eliminated.  Experience in at
least two plants has shown that trace organics or other contaminants
found in the effluent will not adversely affect the lubricants when
this water is recycled back to process emulsions.

Advantages of thermal emulsion breaking include an extremely high
percentage of oil removal, the separation of floating oil from
settleable sludge, and the production of distilled water which is
available for process re-use.  In addition, no chemical additives
are required and the operation is fully automatic, factors which
reduce operating costs and maintenance requirements.  Disadvanta-
ges of this system are the cost of heat to run the small boiler
and the necessary installation of a large storage tank.  Thermal
emulsion breaking models are currently available to handle loads
of 150, 300, and 600 gallons per day-
                             VI1-228

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TREATMENT OF SOLVENT WASTES - ALL OPTIONS

The treatment of solvents that inadvertently enter wastewater
streams from rinses or cleaning operations is covered under the
subsection that deals with "Treatment of Oily Wastes".  Spent
solvents that contain priority pollutants should be segregated
and either contract hauled or reclaimed on site.  Under no
circumstances should priority organics be discharged directly
to waste streams or combined with any wastes that will enter
the waste treatment system.

WASTE SOLVENT CONTROL OPTIONS

The following paragraphs discuss the segregation of waste solvents,
contract hauling of waste solvents, and cleaning alternatives that
can be substituted for solvent degreasing to reduce or eliminate
the quantity of waste solvent generated.

Waste Solvent Segregation

Spent degreasing solvents should be segregated from other process
fluids to maximize the value of the solvents, to preclude the con-
tamination of other segregated wastes (such as oily wastes), and
to prevent the discharge of priority pollutants to any wastewaters.
This segregation can be accomplished by providing and identifying
the necessary storage container(s), establishing clear disposal
procedures, training personnel in the use of these techniques, and
checking periodically to ensure that proper segregation is occuring.
Segregated waste solvents are appropriate for on-site solvent
recovery or can be contract hauled for disposal or reclamation.

Contract Hauling

The DCP data identified several waste solvent haulers, identified
on Table 7-45, most of whom haul solvent in addition to their
primary business of hauling waste oils.  The value of waste solvents
seems to be sufficient to make waste solvent hauling a viable
business.  Telephone interviews indicate that the number of solvent
haulers is increasing and that their operations are becoming more
sophisticated because of the increased value of waste solvent.  In
addition a number of chemical suppliers such as Baron and Blakeslee
include waste hauling costs in their new solvent price.  Some of
the larger solvent refiners make credit arrangements with their
clientele, for example it was reported that one supplier returns
50 gallons of refined solvent for every 100 gallons hauled.
                               VII-229

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                                            TABLE  7-45
                                 WASTE SOLVENT CONTRACT  HAULERS
1.   A.B.C. Waste Oil
     Essington, PA
                                    HABCO Waste Oil
                                    Oak Pond,  MI
                                                                  15.   Shield Oil Co.
                                                                       Elgin, IL
     Waste Oil Co.
     Worcester, MA
                               9.    Elmer  Kearns
                                    High Point,  NC
                                                                  16.   Ashland Chemical
                                                                       So.  Bend, IN
3.   Connecticut Waste Oil
     Tracy, CT
                             10.   US  Service  Corp
                                   Monroeville,  PA
                                                                  17.   Union Chemical
                                                                       Union, ME
4.   American Tank Service
     Ferndale, MI
                             11.   Sealand  Environmental
                                   Engineering
                                   Milford,  CT
                                                                  18.   Solvents Recovery
                                                                       Service  of N.E.
                                                                       Southington, CT
5.   Walters Disposal
     Alliance, OH
                                  12.   Parco Products
                                        (Supplier)
                                        Chicago, IL
                                                             19.  Recycling Industries
                                                                  Braintree, MA
     Carnation Disposal
     Alliance, OH
                             13.   H.O.D.  Disposal
                                   Antioch,  IL
                                                                  20.   Hunt  Chemical Co.
                                                                       (Supplier)
                                                                       Long  Island, NY
Liquid Waste Specialista
Auburn, MA
                                  14.   Baron and Blakeslee
                                        Gardena, CA
                                                                  21.   Fray Supply Co.
                                                                       Tampa,  FL
                                            VI1-230

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Cleaning Alternatives to Solvent Degreasing

The substitution for solvent degreasing of cleaning techniques
that use no solvents or use lesser amounts of solvents would
eliminate or reduce the quantity of priority organics that are
found in wastewaters.  Alternative cleaning methods for the removal
of oils and grease include wiping, immersion, and spray (both
liquid and vapor phase) techniques using water, alkaline or acid
mixtures, and solvent emulsions.  Various methods of agitation,
including ultrasonic and electrolytic are helpful wherever they
are applicable.   Table 7-46 presents a generalized matrix of these
cleaning approaches, each of which has the capability for cleaning
oily metal parts.

Fundamentally,  the factors required to remove oil and clean the
metal surfaces  of a part are:

     1.   A fluid to transport the cleaning agent to and the
          soil  particles away from the surface to be cleaned.
     2.   A chemical in which oily residues are soluble.
     3.   Heat  (temperatures above 150°F) to lower the
          viscosity of the oil and enhance the activity
          of the chemical agent.
     4.   A scrubbing or wiping mechanism to physically
          remove the cleaner and soil.

In the metal finishing industry, the factors that dictate the
cleaning needs  include:

     1.   Production volume
     2.   Product size
     3.   Product material (eg-ferrous, non-ferrous)
     4.   Product shape and complexity (eg-blind holes, internal
          corners)
     5.   Degree of cleanliness required (eg-surface purity)
     6.   Surface preparation required (eg-dry, oil film,
          oxide/scale removal, oxidation resistance)

Obviously, a single cleaning approach is not practicable for all
of these diverse product and manufacturing requirements.  The task
of identifying  feasible cleaning alternatives to solvent degreasing
then becomes one of identifying areas which have similar cleaning
requirements so  that substitution for solvent degreasing is practic-
able.  Typical  areas that are amenable to cleaning techniques other
than solvent degreasing are:

     1.   Low to medium volume production levels where cleaning
          cycle  time does not impact the cost of production
     2.   Non-ferrous products
     3.   Simple product shapes
     4.   Small  parts (adaptable to automated processes)
     5.   Oily  film residue not objectionable
     6.   No exacting surface finishing required.
                              VII-231

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                                  TABLE 7-46
                              CLEANING APPROACHES
CLEANING METHOD
SORBENT   WATER
                                             CLEANING AGENT
ALKALINE  ACID EMULSION  SOLVENT
WIPING
 A.  Dry
 B.  Wet
   X
   X
   X
X
X
X
IMMERSION
 A.  Cold
     1.  without agitation
     2,  with agitation
 B.  Hot
     1.  without agitiation
     2»  with agitation
SPRAY

 A.  Liquid

     1.  Cold
     2.  Hot

 B.  Vapor
            X
            X

            X
                       X
                       X
   X
   X
   X
   X

   X
           X
           X
X
X
X
X

X
       X
       X
          X
          X
X
                                   VII-232

-------
All of the previously described cleaning methods are applicable
to some of these cleaning needs.  For comparative purposes,  these
cleaning processes have been ranked on the relative basis of cost,
quality of cleaniness, and significant environmental effects.
This relative ranking is presented in Table 7-47 for the five
general cleaning methods.  The bases for the criteria used for
relative ranking are defined as follows:

     1.   Cost - include equipment, facilities, chemicals,
          heat, power, maintenance, operation  (rinsing and
          drying where applicable) and wastewater treatment.
     2.   Cleanliness Quality - surface purity.
     3.   Pollution - environmental effects of the process.
     4.   Energy - thermal and electrical energy requirement.

Alkaline cleaning shows the most feasibility as a substitute for
solvent degreasing.  This selection is based in part of the  fact
that the combined alkaline cleaning environmental ranking and the
mean overall ranking are lowest.  Further, data derived from
existing cleaning processes, shows that alkaline cleaning is
only 14% less cost effective than vapor degreasing.  It is believed
that further development of alkaline cleaners and the associated
equipment should make its cost effectiveness equivalent to or
better than that for solvent degreasing.  The major advantage of
alkaline cleaning over solvent degreasing is the elimination or
reduction in the amount of priority pollutants being discharged.
A major disadvantage connected with alkaline cleaning is the energy
consumption.  Another disadvantage is the fact that the process
itself tends to dilute the oils removed and discharges these
diluted oils as well as the cleaning additive, whereas in solvent
degreasing, the oils are contractor hauled along with the spent
solvent and not discharged.

However, at least one firm produces a close-loop alkaline cleaning
system oil separator that is illustrated in Figure 7-102.

This system provides in-process removal of oils and metals wastes
which extends the useful alkaline cleaner life and significantly
reduces treatment requirements because the spent cleaning solution
is normally contract hauled.  Only the alkaline solution dragout
to a subsequent rinsing operation produces a waste that requires
treatment.  Best described as a continuous-batch oil separator,
the system has dual compartments holding caustic wash solution,
each equipped with an oil skimmer and separated by a waste tank.
Piping leads from each compartment to a series of washers and
back to a pump.  Automated valves control flow from the pump to
one of the compartments.  One compartment continuously supplies
caustic solution to a group of washers as the other stands for 24
hours, allowing heavy materials to settle at the bottom as sludge
and permitting the oils to float to the surface.  There, surface
oils are skimmed off, drained into the waste tank, and periodically
drawn off for reclamation or reuse.  While one wash solution in the
                             VII-233

-------
                                  TABLE  7-47
                      CLEANING PROCESS RELATIVE RANKING
                             (LOWEST NUMBER IS  BEST)
 CLEANING METHOD
COST
                                                MEAN
CLEANINESS            ENVIRONMENTAL           OVERALL
  QUALITY    POLLUTION   ENERGY   COMBINED    RANKING
Solvent Degreasing

Emulsion Cleaning

Alkaline Cleaning

Acid Cleaning

Hot Water/Steam Cleaning
1
3
2
4
5
3
4
2
1
5
5
4
2
3
1
1
2
3
4
5
3
3
2.5
3.5
3
2.5
3.25
2.25
3
4
                                     VII-234

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                                                                                Make up
                                                                                 water „
N)
U)
                                           Collection
                                             sump
                                                                                      Oily parts
                                                                                        feed
                                                                                                    X-'
                                                                                                                          Reuseable
                                                                                                                           alkaline
                                                                                                                        cleaning water
                                                                            FIGURE  7-102
                                                                 ALKALINE  WASH  OIL  SEPARATOR

-------
first compartment is undergoing treatment, the clean solution in
the other compartment is circulated to the washers.  The system
has been demonstrated using Blakesleee, Ransehoff, and Combustion
Engineering alkaline cleaning equipment.  Four plants have these
systems in operation and one installation has been in use since
June 1975.  At this facility they report zero discharge (via con-
tract hauling the spent cleaning solution) and the reclamation of
25,000 gallons of oil annually from a cleaning operation prior to
heat treatment.  The specific advantages of applying this type of
in-process oil/metal treatment are as follows:

     1.   The concentrated discharges of spent alkaline cleaning
          baths are eliminated by contract hauling the reduced
          volume of spent cleaner.
     2.   Energy requirements are lowered because of water con-
          servation .
     3.   Water and air pollution resulting from alkaline cleaning
          are less than for the solvent degreasing operation.
     4.   Oil reclamation is accomplished.
     5.   Lower cleaning costs are available through the con-
          servation of cleaning agent and heat; less frequent
          waste hauling; the use of cold cleaners; and lowered
          treatment requirements.
                              VI1-236 A

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                                   Table 7-38
                Classes of Organic Compounds Adsorbed on Carbon
Organic Chemical Class

Aromatic Hydrocarbons

Polynuclear Aromatics


Chlorinated Aromatics



Phenolics


Chlorinated Phenolics
*High Molecular Weight Aliphatic and
 Branch Chain Hydrocarbons

Chlorinated Aliphatic Hydrocarbons
*High Molecular Weight Aliphatic Acids
 and Aromatic Acids

*High Molecular Weight Aliphatic Amines
 and Aromatic Amines

*High Molecular Weight Ketones, Esters,
 Ethers & Alcohols

Surfactants

Soluble Organic Dyes
Examples of Chemical Class;

benzene, toluene, xylene

naphthalene, anthracene
biphenyls

chlorobenzene, polychlorinated
biphenyls, aldrin, endrin,
toxaphene, DDT

phenol, cresol, resorcenol
and polyphenyls

trichlorophenol, pentachloro-
phenol

gasoline, kerosine
1,1,1-Trichloroethane, tri-
chloroethylene, carbon tetra-
chloride, perchloroethylene

tar acids, benzoic acid
aniline, toluene diamine


hydroquinone, polyethylene
glycol

alkyl benzene sulfonates

methylene blue, Indigo carmine
* High Molecular Weight includes compounds in the range of
  4 to 20 carbon atoms
                                  VII-236

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TREATMENT OF SLUDGES

Sludges are created by waste treatment alternatives which remove
solids from wastewater.  Removal of sludges from the treatment
system as soon as possible in the treatment process minimizes re-
turning pollutants to the waste stream through re-solubilization.
One plant visited during this program (ID# 23061) utilized a set-
tling tank in their treatment system that required periodic cleaning.
Such cleaning had not been done for some time, and our analysis
of both their raw and treated wastes showed little difference.
Subsequent pumping out of this settling tank resulted in an
improved effluent (Reference Table 7-48).

Once removed from the primary effluent stream, waste sludges must
be disposed of properly.  If landfills are used for sludge disposal,
the landfill must be designed to prevent material from leaching
back into the water supply.  Mixing of waste sludges which might
form soluble compounds should be prevented.  If sludge is disposed
of by incineration, the burning must be carefully controlled to
prevent air pollution.  A licensed scavenger may be substituted for
plant personnel to oversee disposal of the removed sludge.

                         TABLE 7-48
          COMPARISON OF WASTEWATER AT PLANT ID 23061
          BEFORE AND AFTER PUMPING OF SETTLING TANK
Parameter
                     Concentration (mg/1)
                     Before Sludge Removal
                      Concentration  (mg/1)
                       After Sludge  Removal
          Hexavalent
          Total
                     Total Raw
                       Waste
Cyanide, Amen, to
Chlorination
Cyanide, Total
Phosphorus
Silver
Gold
Cadmium
Chromium,
Chromium,
Copper
Iron
Fluoride
Nickel
Lead
Tin
Zinc
Total Suspended Solids
0.007
0.025
2.413
0.001
0.007
.001
0.005
0.023
0.028
0.885
0.16
0.971
0.023
0.025
0.057
17.0
                                 Treated
                                 Effluent
0.001
0.035
2.675
0.001
0.010
.006
0.105
0.394
0.500
3.667
0.62
1.445
0.034
0.040
0.185
36.00
                       Total Raw
                         Waste
0.005
0.005
14.35
0.002
0.005
.005
0.005
0.010
0.127
2.883
0.94
0.378
0.007
0.121
0.040
67.00
                         Treated
                         Effluent
0.005
0.005
13.89
0.003
0.005
.002
0.005
0.006
0.034
1.718
0.520
0.312
0.014
0.134
0.034
4.00
                               VII-237

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Sludges are typically one to two percent solids and  should  be  de-
watered to lessen space requirements if sludges are  landfilled on
the plant site and to decrease shipping costs  if sludges  are hauled
away by a contractor.  Applicable sludge dewatering  techniques
include gravity sludge thickening, pressure filtration, vacuum
filtration, centrifugation and sludge bed drying.  These  techniques
are discussed in the following subsections.

GRAVITY SLUDGE THICKENING

Description of the Process

In the gravity thickening process, dilute sludge is  fed from a
primary settling tank or clarifier to a thickening tank.  Rakes
stir the sludge gently to densify the sludge and to  push  it to
a central collection well.  The supernatant is returned to  the
primary settling tank.  The thickened sludge that collects  on
the bottom of the tank is pumped to dewatering equipment  or
hauled away.  Figure 7-103 shows the construction of a gravity
thickener.

Application and Performance

Thickeners are generally used in facilities where the sludge is
to be further dewatered by a compact mechanical device such as a
vacuum filter or centrifuge.  Doubling the solids content in the
thickener substantially reduces capital and operating cost  of  the
subsequent dewatering device and also reduces cost for hauling.  The
process is potentially applicable to almost any industrial  plant.

Organic sludges from sedimentation units of one to two percent
solids concentration can usually be gravity thickened to  six to ten
percent; chemical sludges can be thickened to four to six percent.

Advantages and Limitations

The principal advantage of a gravity sludge thickening process is
that it facilitates further sludge dewatering.  Other advantages
are high reliability and minimum maintenance requirements.

Limitations of the sludge thickening process are its sensitivity to
the flow rate through the thickener and the sludge removal  rate.
These rates must be low enough not to disturb the thickened sludge.

Operational Factors

Reliability;  Reliability is high assuming proper design  and
operation.  A gravity thickener is designed on the basis  of square
feet per pound of solids per day, in which the required surface area
is related to the solids entering and leaving the unit.   Thickener
area requirements are also expressed in terms of mass loading, grams
of solids per square meter per day (pounds per square foot  per day).
                              VII-238

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               JTHICKENING;
                  ;TANK:
SLUDGE PUMP
•*•
                 tb
                            OVERFLOW
                            RECYCLED
                             THROUGH
                              PLANT
               FIGURE 7-103

          MECHANICAL GRAVITY THICKENING
                  VII-239

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Maintainability;  Twice a year,  a  thickener  must  be  shut down for
lubrication of the drive mechanisms.   Occasionally,  water must be
pumped back through the system  in  order  to clear  sludge pipes.

Solid Waste Aspects;  Thickened  sludge from  a  gravity  thickening
processwill usually require further dewatering prior  to disposal,
incineration, or drying.  The clear effluent may  be  recirculated
in part, or it may be subjected  to further treatment prior to
discharge.

Demonstration Status

Gravity sludge thickeners are used throughout  industry to reduce
water content to a level where the sludge may  be  efficiently
handled.  Further dewatering is  usually  practiced to minimize
costs of hauling the sludge to approved  landfill  areas.

Sludge thickening is used in 78  plants in the  present  data base
and are identified in Table 7-49.

                              Table 7-49
      Metal Finishing Plants Employing Gravity/Sludge  Thickening
          03043
          04069
          04071
          04263
          04719
          04981
          05021
          05035
          06052
          08004
          11156
          11177
          11182
          11704
          12033
          12074
          12075
          12078
          12091
          12100

PRESSURE FILTRATION
12102
12709
13031
13040
14061
15042
15044
17061
18050
18091
19063
20005
20010
20064
20073
20075
20078
20082
20085
20116
20120
20157
20165
20248
20291
21078
23062
23337
25001
27044
28082
28115
30079
30087
30090
30151
30153
30927
30967
33065
33070
33113
33120
36085
36090
36091
36092
36112
36130
36180
36623
40061
40063
41151
43003
43052
44044
62032
Description of_ the Process

Pressure filtration is achieved by pumping the liquid through a
filter material which is impenetrable to the solid phase.  The
                            VI1-240

-------
positive pressure exerted by the feed pumps or other mechanical
means provides the pressure differential which is  the  principal
driving force.  Figure 7-104 represents the operation  of  one  type
of pressure filter.

A typical pressure filtration unit consists of a number of plates
or trays which are held rigidly in a frame to ensure alignment and
are pressed together between a fixed end and a traveling  end.  On
the surface of each plate is mounted a filter made of  cloth or a
synthetic fiber.  The sludge is pumped into the unit and  passes
through feed holes in the trays along the length of the press until
the cavities or chambers between the trays are completely filled.
The solids in the sludge are then entrapped, and a cake begins to
form on the surface of the filter material.  The water passes
through the fibers, and the solids are retained.

At the bottom of the trays are drainage ports.  The filtrate  is
collected and discharged to a common drain.  As the filter medium
becomes coated with sludge, the flow of filtrate through  the  filter
drops sharply, indicating that the capacity of the filter has been
exhausted.  The unit must then be cleaned of the sludge.  After the
cleaning or replacement of the filter media, the unit  is  again ready
for operation.

Application and Performance

Because dewatering is such a common operation in treatment systems,
pressure filtration is a technique which can be found  in  many in-
dustry applications concerned with removing solids from their waste
stream.  In a typical pressure filter, chemically preconditioned
sludge detained in the unit for one to three hours under  pressures
varying from 5 to 13 atmospheres exhibited final moisture content
between 50 and 75 percent.

Advantages and Limitations

The pressures which may be applied to a sludge for removal of water
by filter presses that are currently available range from 5 to 13
atmospheres.  Pressure filtration may also reduce the amount of
chemical pretreatment required.  The sludge, retained  in  the  form of
the filter cake, has a higher percentage of solids than either a
centrifuge or vacuum filter yield.  Thus, the sludge can  be easily
accommodated by materials handling systems.

Two disadvantages associated with pressure filtration  in  the past
have been the short life of the filter cloths and lack of automation
New synthetic fibers have largely offset the first of  these problems
Also,  units with automatic feeding and pressing cycles are now avail-
able.
                             VI1-241

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  PERFORATED
  BACKING PLATE
 FABRIC
 FILTER MEDIUM
SOLID
RECTANGULAR
END PLATE
                                                 FABRIC
                                                 FILTER MEDIUM
                                                 ENTRAPPED SOLIDS
                                                  PLATES AND FRAMES ARE PRESSED
                                                  TOGETHER DURING FILTRATION
                                                  CYCLE
                                                 RECTANGULAR
                                                 METAL PLATE
          FILTERED LIQUID OUTLET
                                           RECTANGULAR FRAME
                               FIGURE 7-104
                              PRESSURE FILTRATION
                                VI1-242

-------
For larger operations, the relatively high space requirements,  as
compared to those of a centrifuge, also can be considered  as  a
disadvantage.

Operational Factors

Reliability;  Assuming proper pretreatment, design, and  control,
pressure filtration is a highly dependable system.

Maintainability;  Maintenance consists of periodic cleaning or
replacement of the filter media, drainage grids, drainage  piping,
filter pans, and other parts of the system.   If the removal of
the sludge cake is not automated, additional  time is required
for this operation.

Solid Waste Aspects;  Because it is generally drier than other  types
of sludges, the filter sludge cake can be handled with relative ease
Disposal of the accumulated sludge may be accomplished by  any of the
accepted procedures.

Demonstration Status

Pressure filtration is a commonly used technology that is  currently
utilized in a great many commercial applications.

Pressure filtration is used in 66 plants in the present data base
and these are identified in Table 7-50.

VACUUM FILTRATION

Description o_f the Process

In wastewater treatment plants, sludge dewatering by vacuum
filtration is an operation that is generally accomplished  on
cylindrical drum filters.  These drums have a filter medium
which may be cloth made of natural or synthetic fibers, coil
springs, or a wire-mesh fabric.  The drum is suspended above and
dips into a vat of sludge.  As the drum rotates slowly, part of
its circumference is subject to an internal vacuum that draws
sludge to the filter medium.  Water is drawn through the porous
filter cake to a discharge port, and the dewatered sludge, loosened
by compressed air, is scraped from the filter mesh.  Because the
dewatering of sludge on vacuum filters is relativley expensive  per
kilogram of water removed, the liquid sludge  is frequently
thickened prior to processing.  A vacuum filter is shown in Figure
7-105.

Application and Performance

Vacuum filters are frequently used both in municipal treatment
plants and in a wide variety of industries for dewatering  sludge.
                             VII-243

-------
                    Table 7-50
Metal Finishing Plants Employing Pressure Filtration
          01002
          01003
          10007
          03043
          04069
          04146
          04276
          04284
          05050
          06050
          06077
          06107
          06153
          06960
          08060
          09046
          11096
          11103
          11115
          12005
          12065
          12071
12074
13031
14060
19066
19083
20022
20070
20083
20115
20255
20483
23039
23076
27042
27044
27045
28043
28121
30087
30927
30967
31021
31033
31035
31068
31070
33110
33113
33148
33172
33195
33293
34050
35041
36102
36176
38223
40047
41051
41068
42030
44044
47025
47074
                       VII-244

-------
                FABRIC OR WIRE
                FILTER MEDIA
                STRETCHED OVER
                REVOLVING DRUM
                                                         DIRECTION OF ROTATION
           ROLLER
                             STEEL
                             CYLINDRICAL
                             FRAME
                                              THROUGH
                                              MEDIA BY
                                              MEANS OF
                                              VACUUM
SOLIDS SCRAPED
OFF FILTER MEDIA
SOLIDS COLLECTION
HOPPER
                                                                  INLET LIQUID
                                                                  TO BE
                                                                  FILTERED
                                         FILTERED LIQUID
                                   FIGURE  7-105

                                 VACUUM FILTRATION
                                 VI1-245

-------
They are most commonly used in larger facilities, which have  a
thickener to double the solids content of clarifier sludge  before
vacuum filtering.  The function of vacuum filtration  is to  reduce
the water content of sludge, so that the proportion of solids
increases from about 5 percent to about 30 percent.

Advantages and Limitations

Although the initial cost and area requirement of the vacuum  fil-
tration system are higher than those of a centrifuge, the operating
cost is lower, and no special provisions for sound and vibration
protection need be made.  The dewatered sludge from this process
is in the form of a moist cake and can be conveniently handled.

Operational Factors

Reliability;  Vacuum filter systems have been proven  reliable at
many industrial and municipal treatment facilities.  At present,
the largest municipal installation is at the West Southwest waste-
water treatment plant of Chicago, Illinois, where 96  large  filters
were installed in 1925, functioned approximately 25 years,  and then
were replaced with larger units.  Original vacuum filters at
Minneapolis-St. Paul, Minnesota now have over 28 years of continuous
service, and Chicago has some units with similar or greater service
life.

Maintainability;  Maintenance consists of the cleaning or
replacement of the filter media, drainage grids, drainage piping,
filter pans, and other parts of the equipment.  Experience  in a
number of vacuum filter plants indicates that maintenance consumes
approximately 5 to 15 percent of the total time.  If carbonate
buildup or other problems are unusually severe, maintenance time
may be as high as 20 percent.

If intermittent operation is to be employed, the filter equipment
should be drained and washed each time it is taken out of service
and an allowance for wash time should be made in the selection of
sludge filtering schedules.

Solid Waste Aspects;  Vacuum filters generate a solid cake.  All
of the metals extracted from the plant wastewater are concentrated
in the filter cake as hydroxides, oxides, sulfides, or other salts.
These metals are subject to leaching into ground water, especially
under acid conditions.

Demonstration Status

Vacuum filtration has been widely used for many years.  It  is a
fully proven, conventional technology for sludge dewatering.
                                VII-246

-------
Vacuum filtration is used in 68 plants in the present data base
and these are identified in Table 7-51.

CENTRIFUGATION

Description Of The Process

Centrifugation is the application of centrifugal force to separate
solids and liquids in a liquid/solid mixture or to effect concen-
tration of the solids.  The application of centrifugal force  is
effective because of the density differential normally found  be-
tween the insoluble solids and the liquid in which they are con-
tained.  As a waste treatment procedure, centrifugation is applied
to dewatering of sludges.  One type of centrifuge is shown in
Figure 7-106.

There are three common types of centrifuges:  the disc, basket, and
conveyor type.  All three operate by removing solids under the
influence of centrifugal force.  The fundamental difference between
the three types is the method by which solids are collected and
discharged.

In the disc centrifuge, the sludge feed is distributed between
narrow channels that are present as spaces between stacked conical
discs.  Suspended particles are collected and discharged continu-
ously through small orifices in the bowl wall.  The clarified
effluent is discharged through an overflow weir.

A second type of centrifuge which is useful in dewatering sludges
is the basket centrifuge.  In this type of centrifuge, sludge
feed is introduced at the bottom of the basket, and solids collect
at the bowl wall while clarified effluent overflows the lip ring
at the top.  Since the basket centrifuge does not have provision
for continuous discharge of collected cake, operation requires
interruption of the feed for cake discharge for a minute or two in
a 10 to 30 minute overall cycle.

The third type of centrifuge commonly used in sludge dewatering is
the conveyor type.  Sludge is fed through a stationary feed pipe
into a rotating bowl in which the solids are settled out against the
bowl wall by centrifugal force.  From the bowl wall, they are moved
by a screw to the end of the machine, at which point whey are dis-
charged.  The liquid effluent is discharged through ports after
passing the length of the bowl.
                                 VII-247

-------
                    Table 7-51
Metal Finishing Plants Employing Vacuum Filtration
          02062
          03041
          03042
          06037
          06074
          06087
          06088
          06152
          09052
          09060
          11182
          11704
          12002
          12014
          12042
          12075
          12078
          12091
          12709
          15058
          15070
          16544
          17030
18050
19084
19090
20005
20010
20073
20077
20080
20100
20161
20175
20248
20249
20291
21078
28115
30079
30090
30153
30927
31044
31047
33092
33110
33120
33124
33195
33263
34036
34036
36040
36092
36113
36130
36623
38217
40037
40063
40067
40079
41097
41151
42030
43003
44036
                          VII-248

-------
CONVEYOR DRIVE

    • BOWL DRIVE
                                           LIQUID ZONE-
                                  l&^^g^\K>V!tt.W>*ftCi^xCfc^f;9;?ttftW/
-------
Application And Performance

Virtually all of those industrial waste  treatment  systems  producing
sludge can utilize centrifugation to dewater  it.   Centrifugation
is currently being used by a wide range  of  industrial  concerns.
The performance of sludge dewatering by  centrifugation depends on
the feed rate, the rotational velocity of the drum,  and the  sludge
composition and concentration.  Assuming proper design and operation,
the solids content of the sludge can be  increased  to 20-35 percent.

Advantages And Limitations

Sludge dewatering centrifuges have minimal  space requirements and show
a high degree of effluent clarification.  The operation is simple,
clean, and relatively inexpensive.  The  area  required  for  a  centrifuge
system installation is less than that required for a filter  system or
sludge drying bed of equal capacity, and the  initial cost  is lower.

Centrifuges have a high power cost that  partially offsets  the low
initial cost.  Special consideration must also be given to providing
sturdy foundations and soundproofing because of the  vibration and
noise that result from centrifuge operation.  Adequate  electrical
power must also be provided since large  motors are required.  The
major difficulty encountered in the operation of centrifuges has
been the disposal of the concentrate which  is relatively high in
suspended, non-settling solids.

Operational Factors

Reliability:  Its reliability is high, assuming proper  control of
factors such as sludge feed, consistency, and temperature-   Pre-
treatment such as grit removal and coagulant addition  may  be
necessary.  Pretreatment requirements will  vary depending  on the
composition of the sludge and on the type of centrifuge employed.

Maintainability;  Maintenance consists of periodic lubrication,
cleaning, and inspection.  The frequency and degree  of  inspection
required varies depending on the type of sludge solids  being de-
watered and the maintenance service conditions.  If  the sludge is
abrasive, it is recommended that the first  inspection  of the ro-
tating assembly be made after approximately 1,000 hours of operation.
If the sludge is not abrasive or corrosive, then the initial inspec-
tion might be delayed.  Centrifuges not  equipped with  a continuous
sludge discharge system require periodic shutdowns for  manual sludge
cake removal.
                             VI1-250

-------
Solid Waste Aspects;  Sludge dewatered in the centrifugation process
may be heat dried or it may be disposed of by incineration or by
other direct means.  The clarified effluent (centrate),  if high in
dissolved or suspended solids, may require further treatment prior
to discharge.

Demonstration Status

Centrifugation is currently used in a great many commercial appli-
cations to dewater sludge.  Work is underway to improve  the effici-
ency, increase the capacity, and lower the costs associated with
centrifugation.

Centrifugation is used in 55 plants in the present data  base
and these are identified in Table 7-52.

SLUDGE BED DRYING

Description of_ the Process

As a waste treatment procedure, sludge bed drying is employed
to reduce the water content of a variety of sludges to the point
where they are amenable to mechanical collection and removal.  These
beds usually consist of 15.24 to 45.72 cm (6 to 18 inches) of sand
over a 30.48 cm (12 inch) deep gravel drain system made  up of 3.175
to 6.35 mm (1/8 to 1/4 inch) graded gravel overlying drain tiles.

Drying beds are usually divided into sectional areas approximately
7.62 meters (25 feet) wide x 30.48 to 60.96 meters (100  to 200 feet)
long.  The partitions may be earth embankments, but more often are
made of planks and supporting grooved posts.

To apply liquid sludge to the sand bed, a closed conduit or a
pressure pipeline with valved outlets at each sand bed section is
often employed.  Another method of application is by means of an
open channel with appropriately placed side openings which are
controlled by slide gates.  With either type of delivery system, a
concrete splash slab should be provided to receive the falling
sludge and prevent erosion of the sand surface.

Where it is necessary to dewater sludge continuously throughout
the year regardless of the weather, sludge beds may be covered with
a fiberglass reinforced plastic roof.  Covered drying beds permit
a greater volume of sludge drying per year in most climates because
of the protection afforded from rain or snow and because of more
efficient control of temperature.  Depending on the climate, a
combination of open and enclosed beds will provide maximum utili-
zation of the sludge bed drying facilities.
                              VII-251

-------
                    Table 7-52
 Metal Finishing Plants Employing Centrifugation
02032
04151
04153
06006
06071
06075
06086
06148
11050
11125
11127
12005
12033
12061
12075
12077
14062
15044
17050
19067
19068
19104
19107
19462
20070
20079
20106
20140
20149
20241
20708
21062
21065
21074
23048
27044
30097
30111
30155
30927
31022
33024
33071
34051
36091
36937
38052
41086
41116
41629
41869
44040
44150
45041
47041
                    VII-252

-------
Application and Performance

Sludge drying beds are a common means of dewatering sludge  from
clarifiers and thickeners.  They are widely used both  in municipal
and industrial treatment facilities.

Dewatering of sludge on sand beds occurs by two mechanisms:
filtration of water through the bed and evaporation of water as
a result of radiation and convection.  Filtration is generally
complete in one to two days and may result in solids concentrations
as high as 15 to 20 percent.  The rate of filtration depends on the
drainability of the sludge.

The rate of air drying of sludge is related to temperature, relative
humidity, and air velocity.  Evaporation will proceed at a  constant
rate to a critical moisture content, then at a falling rate to an
equilibrium moisture content.  The average evaporation rate for a
sludge is about 75 percent of that from a free water surface.

Advantages and Limitations

The main advantage of sand drying beds over other types of  sludge
dewatering is the relatively low cost of construction, operation,
and maintenance.  Its disadvantages are the large area of land re-
quired and long drying times that depend, to a great extent, on
climate and weather.

Operational Factors

Reliability;  High, assuming favorable climatic conditions, proper
bed design, and care to avoid excessive or unequal sludge appli-
cation.  If climatic conditions in a given area are not favorable
for adequate drying, a cover may be necessary.

Maintainability;  Maintenance consists basically of periodic re-
moval of the dried sludge.  Sand removed from the drying bed with
the sludge must be replaced and the sand layer resurfaced.

The resurfacing of sludge beds is the major expense item in sludge
bed maintenance, but there are other areas which may require
attention.  Underdrains occasionally become clogged and have to be
cleaned.  Valves or sludge gates that control the flow of sludge
to the beds must be kept watertight.  Provision for drainage of
lines in winter should be made to prevent damage from freezing.  The
partitions between beds should be tight so that sludge will not flow
from one compartment to another.  The outer walls or banks  around
the beds should also be watertight.
                             VII-253

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Solid Waste Aspects;  The full sludge drying bed must either  be
abandoned or the collected solids must be removed.  These  solids
contain whatever metals or other materials were settled  in the
clarifier.  Metals will be present as hydroxides, oxides,  sulfides,
or other salts.  They have the potential for leaching and  contam-
inating ground water, whatever the location of the semidried  solids.
Thus an abandoned bed should include provision for runoff  control
and leachate monitoring.

Demonstration Status

Sludge beds have been in common use in both municipal and  industrial
facilities for many years.  However, protection of ground  water from
contamination is not always adequate.  Sludge bed drying is used
in 77 plants in the present data base and these are identified in
Table 7-53.

SLUDGE DISPOSAL

There are several methods of disposal of sludges from industrial
wastewater treatment.  The two most common techniques are  land-
filling by the company on its own property and removal by  licensed
contractor to an outside landfill or reclamation point.  Other dis-
posal techniques used for industrial waste sludges include  incin-
eration, lagooning, evaporative ponds, and pyrolysis.  This latter
technique produces a dewatered ash or sludge which requires ulti-
mate disposal by either contractor hauling or on-site landfilling.

IN-PROCESS CONTROL TECHNOLOGY

This section presents flow guidance and process controls in the
form of available methods and practices which can help reduce the
water usuage and pollution discharge at metal finishing facilities.
The in-process control technologies described below include tech-
niques for:

          Flow reduction through efficient rinsing
          Process bath conservation
          Waste oil segregation
          Process bath segregation
          Process modification
          Cutting fluid cleaning
          Integrated waste treatment
          Good housekeeping

These techniques deal with reducing water usage and with efficient
handling of process wastes.  All of the areas of in-process con-
trol are presented in the following sections.
                              VI1-254

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                     Table 7-53
Metal Finishing Plants Employing Sludge Drying Beds
 01067
 01068
 04076
 04262
 05050
 06002
 06035
 06051
 06067
 06073
 06076
 06081
 06083
 06084
 06091
 06094
 06101
 06113
 06117
 06119
06124
06128
06138
06360
08061
08072
09025
09047
11008
11113
11152
11173
12075
13041
14061
14062
15048
17061
18050
19050
20003
20064
20082
20085
20247
21003
22735
23039
23070
23072
25001
30009
30031
30064
30519
31032
31050
31067
33024
33047
33050
33179
33184
33200
33287
36001
36082
36083
36592
38039
40062
40075
40079
40836
41068
45035
47412
                       VI1-255

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FLOW REDUCTION THROUGH EFFICIENT RINSING

Reductions in the amount of water used in metal finishing can be
realized through installation and use of efficient rinse techni-
ques.  Cost savings associated with water use reduction result
from lower cost for rinse water and reduced chemical costs  for
wastewater treatment.  An added benefit is that the waste treatment
efficiency is also improved.  It is estimated that rinse steps may
consume over 90 percent of the water used by a typical metal fini-
shing facility.  Consequently, the greatest water use reductions
can be anticipated to come from modifications of rinse techniques.

Rinsing is essentially a dilution step which reduces the concen-
tration of contaminants on the work piece.  The design of rinse
systems for minimum water use depends on the maximum level  of con-
tamination allowed to remain on the work piece (without reducing
acceptable product quality or causing poisoning of a subsequent
bath) as well as on the efficiency or effectiveness of each rinse
stage.

A rinse system should be considered efficient if the dissolved
solids concentration is reduced just to the point where no  noti-
ceable effects occur either as a quality problem or as excessive
drag-in to the next process step.  Operation of a rinse tank or
tanks which achieve a 10,000 to 1 reduction in concentration
where .only a 1,000 to 1 reduction is required represents ineffi-
cient use of water.  Operating rinse tanks at or near their maxi-
mum acceptable level of contamination provides the most efficient
and economical form of rinsing.  Insufficient operation manifests
itself in higher operating costs not only from the purchase cost
of water, but also from the treatment of it.

Since the purpose of rinsing is to remove process solution
dragout from the surface of the workpiece, the best way to
reduce the amount of rinsing required to reduce the dragout.
A reduction in dragout results in a reduction of waste that
has to be treated.  Dragout is a function of several factors
including workpiece geometry, viscosity and surface tension of
the process solution, withdrawal and drainage time and racking.
These factors affecting dragout are described below-

     1.   Geometry of the Part - This partly determines the
          amount of dragout contributed by a part and is one
          of the principal determinants for the type of rin-
          sing arrangement selected.  A flat sheet with holes
          is well suited for an impact spray rinse rather than
          an immersion rinse, but for parts with cups or recesses
          such as a jet fuel control, a spray rinse is totally
          ineffective.
                                VI1-256

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2.    Kinematic Viscosity of the Process Solution - The
     kinematic viscosity Ts an important factor in de-
     termining process bath dragout.  The effect of in-
     creasing kinematic viscosity is that it increases
     the dragout volume in the withdrawal phase and de-
     creases the rate of draining during the drainage
     phase.   It is advantageous to decrease the dragout
     and increase the drainage rate.  Consequently, the
     process solution kinematic viscosity should be as
     low as  possible.  Increasing the temperature of the
     solution decreases its viscosity, thereby reducing
     the volume of process solution going to the rinse
     tank.   Care must be exercised in increasing bath
     temperature, particularly with electroless plating
     baths,  because the rate of bath decomposition may
     increase significantly with temperature increases.

3.    Surface Tension of: the Process Solution - Surface
     tension is a major factorthat controls the removal
     of dragout during the drainage phase.   To remove a
     liquid  film from a solid surface, the  gravitation
     force must overcome the adhesive force between the
     liquid  and the surface.  The amount of work required
     to remove the film is a function of the surface ten-
     sion of the liquid and the contact angle.  Lowering
     the surface tension reduces the amount of work re-
     quired  to remove the liquid and reduces the edge
     effect  (the bead of liquid adhering to the edges of
     the part).  A secondary benefit of lowering the
     surface tension is to increase the metal uniformity
     reduced by increasing the temperature  of the process
     solution or more effectively, by use of a wetting
     agent.

4.    Time of Withdrawal and Drainage - The  withdrawal
     velocity of a part from a solution has an effect
     similar to that of kinematic viscosity.  Increasing
     the velocity or decreasing the time of withdrawal
     increases the volume of solution that  is retained
     by the  part.  Since time is directly related to
     production rate, it is more advantageous to reduce
     the dragout volume initially adhering  to the part
     rather  than attempt to drain a large volume from
     the part.
                           VII-257

-------
     5.    Racking - Proper racking of parts is the most
          effective way to reduce dragout.  Parts would
          be arranged so that no cup-like recesses are
          formed, the longest dimension should be hori-
          zontal, the major surface vertical, and each
          part should drain freely without dripping onto
          another part.  The racks themselves should be
          periodically inspected to insure the integrity
          of the rack coating.  Loose coatings can con-
          tribute significantly to dragout.  Physical or
          geometrical design of racks is of primary con-
          cern for the control of dragout both from the
          racks and the parts themselves.  Dragout from
          the rack itself can be minimized by designing
          it to drain freely such that no pockets of
          process solution can be retained.

The different types of rinsing commonly used within the metal
finishing industry are described below.

     1.    Single Running Rinse - This arrangement requires a
          large volume of water to effect a large degree of
          contaminant removal.  Although in widespread use,
          single running rinsing rinse tanks should be modified
          or replaced by a more effective rinsing arrangement
          to reduce water use.

     2.    Countercurrent Rinse - The countercurrent rinse pro-
          vides for the most efficient water usage and thus, where
          possible, the countercurrent rinse should be used.
          There is only one fresh water feed for the entire set
          of tanks, and it is introduced in the last tank of
          the arrangement. The overflow from each tank becomes
          the feed for the tank preceding it.  Thus, the con-
          centration of dissolved salts decreases rapidly from
          the first to the last tank.

          In a situation requiring a 1,000 to 1 concentration re-
          duction , the addition of a second rinse tank (with a
          countercurrent flow arrangement) will reduce the theo-
          retical water demand by 97 percent.

     3.    Series Rinse - The major advantage of the series rinse
          over the countercurrent system is that the tanks of the
          series can be individually heated or level controlled
          since each has a separate feed.  Each tank reaches its
          own equilibrium condition; the first rinse having the
          highest concentration, and the last rinse having the
          lowest concentration.  This system uses water more
          efficiently than the single running rinse, and the con-
          centration of dissolved salts decreases in each successive
          tank.
                               VII-258

-------
     4.    Spray Rinse - Spray rinsing is considered the most
          efficient of the various rinse techniques in continuous
          dilution rinsing.  The main concern encountered in use
          of this mode is the efficiency of the spray (i.e., the
          volume of water contacting the part and removing
          contamination compared to the volume of water discharged).
          Spray rinsing is well suited for flat sheets.  The im-
          pact of the spray also provides an effective mechanism
          for removing dragout from recesses with a large width to
          depth ratio.

     5.    Dead, Still, or Reclaim Rinses - This form of rinsing is
          particularly applicable forTnitial rinsing after metal
          plating because the dead rinse allows for easier recovery
          of the metal and lower water usage.  The rinsing should
          then be continued in a countercurrent or spray arrangement.

The use  of different rinse types will result in wide variations in
water use.  Table 7-54 shows the theoretical flow requirements for
several  different rinse types to maintain a 1,000 to-1 reduction in
concentration.  Table 7-55 shows the mean flows (1/m ) found at
sampled  plants for three rinse water-intensive operations.

By combining different rinse techniques, a plant can greatly re-
duce water consumption and in some cases form a closed loop rin-
sing arrangement.  Some examples of primary rinse types and special-
ized rinsing arrangements applicable to metal finishing are dis-
cussed below.

Closing  The Loop With A Countercurrent Rinse - This particular
arrangement is well suTted for use with heated process baths.
The overflow from the countercurrent rinse becomes the evaporative
makeup for the process bath.  By installing the proper number of
countercurrent tanks, the fresh feed rate for a given dilution
ratio is sized to equal the bath's evaporative rate.  This arrange-
ment is  easily controlled by using liquid level controllers in both
the process bath and rinse tank, a pump to transfer rinse solution
to the process bath, and a solenoid valve on the fresh feed line
for the  rinse tanks.  Plant ID'S 06037, 06072, and 20064 use
this arrangement.

                             TABLE 7-54
     Theoretical Rinse Water Flows Required to Maintain a
               1,000 to 1 Concentration Reduction

Type of_  Rinse            Single         Series         Countercurrent


Number of  Rinses           12323
Required Flow (gpm)         10       0.61      0.27      0.31      0.1
                              VI1-259

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                           TABLE 7-55
     Comparison of Rinse Type Flow Rates for Sampled Plants

                                                         2
                            Rinse Type and Mean Flow (1/m  )

                       Single  2 Stage     2 Stage         3 Stage
Operation              Stage   Series   Countercurrent  Countercurrent

Alkaline Cleaning      1504.   235.6         67.36           28.76

Nickel Electroplate    322.9   88.96         26.54           7.44

Zinc Electroplate      236.8   33.78         21.79           7.84

Closing The Loop With Spray Followed By Countercurrent Rinse -
The spray followed by Countercurrent rinse is well suited  for
flat sheets and parts without complex geometry.  The spray is
mounted over the process bath, and the work is fogged before
moving to the Countercurrent rinse.  A major advantage of  this
arrangement is that the spray reduces concentration of the drag-
out on the part, returning the removed portion to the process tank.
This provides for evaporative makeup of the process bath and a
lower water usage and/or a smaller number of tanks necessary for
the Countercurrent rinse.  Plant ID 40062 utilizes this rinse
technique.

Closing The Loop With Countercurrent Rinsing Followed By Spray
Rinsing - The Countercurrent followed by spray rinsing approach
can be used when a very clean workpiece (and, therefore, final
rinse) is required.  The spray is mounted above the last counter-
current rinse.  Depending on the evaporation rate of the process
solution, the evaporative makeup can come from the first counter-
current tank.

Closing The Loop With Dead RjLnse Followed By Countercurrent -
The dead rinse followed by Countercurrent rinse arrangement is
particularly useful with parts of a complex geometry.  Evapora-
tive losses from the original solution tank can be made up from
the dead rinse tank and the required flow for the Countercurrent
system can be greatly reduced.  The following plants make  use of
this rinsing arrangement:  04045, 06036, 06072, 06081, 06088,
20064, 20073, 20080, 21003, 21651, 30022, 31022, 33065, 33070,
33073, 36041, 41069, 61001.

Closing The Loop With Recirculatory Spray - When the geometry of
the work permits, the recirculating spray offers an improved al-
ternative to the dead rinse.  Operating with a captive supply of
rinse solution, the solution is sprayed onto the work.  The
advantage of this system is that the impact of the spray is used
                                 VI1-260

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to remove dragout, particularly for work with holes in it.  The
basic equations for concentration buildup hold but are modified
by the removal efficiency of the spray.  The required flow rate
of the spray is dependent on the geometry of the parts, the pro-
duction rate and the solution evaporation rate.  Plant ID'S
15608, and 27046 have this rinsing system.

Another method of conserving water through efficient rinsing is
by controlling the flow of the feed water entering the rinse
tanks.  Some flow control methods are listed below.

     1.   Conductivity Controllers - Conductivity controllers
          provide for efficient use and good control of the rinse
          process.  This controller utilizes a conductivity cell
          to measure the conductance of the solution which, for
          an electrolyte, is dependent upon the ionic concentra-
          tion.  The conductivity cell is tied to a controller
          which will open or close a solenoid on the makeup line.
          As the rinse becomes more contaminated, its conductance
          increases until the set point of the controller is
          reached, causing the solenoid to open and allowing make-
          up to enter.  Makeup will continue until the conductance
          drops below the set point.  The advantage of this method
          of control is that water is flowing only when required.
          A major manufacturer of conductivity controllers supplied
          to plants in the Metal Finishing Category claims that
          water usage can be reduced by as much as 50-85% when the
          controllers are used.

     2.   Liquid Level Controllers - These controllers find
          their greatest use on closed loop rinsing systems.
          A typical arrangement uses a liquid level sensor in
          both the process solution tank and in the first rinse
          tank and the process tank, and a solenoid on the rinse
          tank makeup water line.  When the process solution
          evaporates to below the level of the level controller,
          the pump is activated, and solution is transferred
          from the first tank to the process tank.  The pump
          will remain active until the process tank level con-
          troller is satisfied.  As the liquid level of the rinse
          tank drops due to the pumpout, the rinse tank controller
          will open the solenoid allowing fresh feed to enter.

     3.   Manually Operated Valves - Manually operated valves
          are susceptible to misuse and should, therefore, be
          installed in conjunction only with other devices.
          Orifices should be installed in addition to the valve
          to limit the flow rate of rinse water.  For rinse
          stations that require manual movement of work and
          require manual control of the rinse (possibly due to
                              VI1-261

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          low utilization), dead man valves should be installed
          in addition to the orifice to limit the flow rate of
          rinse water.  They should be located so as to
          discourage jamming them open.

     4,   Orifices or Flow Restrictors - These devices are
          usually installed for rinse tanks that have a con-
          stant production rate.  The newer restrictors can
          maintain a constant flow even if the water supply
          pressure fluctuates.  Orifices are not as efficient
          as conductivity or liquid level controllers, but
          are far superior to manual valves.

Process Bath Conservation

There are a number of techniques that are utilized to recover or
reuse process solutions in the metal finishing category.  The
costs and reduced availability of certain process solutions
have encouraged finishers to recognize process solutions as a
valuable resource rather than a disposal problem.  Some ex-
amples of chemical recovery and reuse are:  reprocessing of
oil, reclamation of oil, recycling of oil, reuse of spent
etchants, recovery of metal from spent process baths, regen-
eration of etchants and dragout recovery.  These techniques
are described below.

Reprocessing of Oil - Reprocessing consists of contaminant
removal by physical separation, filtering, centrifuging, or
magnetic separation, as previously discussed.  Reprocessing
also includes the preparation of waste oils for burning as a
fuel supplement.

Reclamation of Oil - Oil reclamation combines the elements of
reprocess ing along with mechanical or chemical steps.  Recla-
mation is used to remove solids and water, fuel or solvents,
and degradation products such as acid.  Two common processes
are flash distillation and chemical adsorption.  The addition
of heat with a partial vacuum and the use of filtration mater-
ial is employed to remove degradation products in used oil.

Reclamation is used with synthetic fluids or highly refined
mineral oils.  Reclamation systems are available for either
fixed or portable operation, and outside reclamation services
are available.

Recycling of Oil - Recycling is the most comprehensive treat-
ment.  The waste oil is prefiltered to remove most of the solids,
solvents/fuel, and water, leaving essentially base oil and addi-
tives.  Removing the additives leaves a high quality basestock.
The basestock is then formulated with conventional additives
and can be used in the same application as the virgin basestock.
                              VII-262

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Re-refining provides the best economics when large volumes of
waste oil are available.  Re-refiners may accept industrial oil
wastes when a large source or many smaller sources of waste oils
are available for collection in a region.

Reuse o_f Spent Etchant - If a facility maintains both an additive
and a conventional subtractive line for the manufacturing of prin-
ted boards, a two-fold incentive exists for reuse of spent copper
etchant.  The copper etchant used in a conventional subtractive
process is normally dumped when the copper concentration reaches
approximately 45,000 mg/1.  However, by removing the iron and
chromium from the etchant, it can become an inexpensive source of
copper for the additive plating baths.  This technique can be exten-
ded to recover the copper bearing waters from copper etchant rinse
tanks as well as from the etch tank and is practiced at Plant ID
11065.  Some concentrating devices, such as vacuum distillation,
may be required to reduce the volume of the rinse.

Recovery of Metal from Spent Plating Baths - Spent plating baths
contain a~~s~ignificant percentage of metal in solution.  Recovery
can be effected by electrolizing the solution at low voltage or by
decomposing a hot bath with seed nuclei.  The resultant material,
while pure, can be refined or sold to recover some of its original
value.  The advantage of this type of treatment is that a large
percentage of the metal is recovered and does not require treatment.
This type of metal recovery is performed by Plant ID's 17061 and
11065.

Regeneration of Etchants - Regeneration of etchants from a copper
etchant solution can be achieved by partially dumping the bath and
then adding fresh make-up acid and water.  If this is done, the
etchant life can be extended indefinitely.  Another method prac-
ticed for the regeneration of etchants used in the electroless
plating of plastics is to oxidize the trivalent chromium back to
the active hexavalent chromium.  The oxidization is done by an
electrolytic cell.  Plant 20064 regenerates its preplate etchants
in this manner.  Use of this method reduces the amount of material
requiring waste treatment.

Reclamation of Paint Powders - A plant which uses powder coating
does not need water wash spray booths to catch overspray.  The
oversprayed particles can be collected with a vacuum arrangement
in a dry booth, filtered, and reused on the production line.

Dragout Recovery - If the overflow water from a rinse tank can be
reused, it does not have to be treated, and additional water does
not have to be purchased.  One approach currently in use is to re-
place the evaporative losses from the process bath with overflow
from the rinse station.  This way a large percentage of process
solution normally lost by dragout can be returned and reused.
                              VII-263

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The usefulness of this method depends on  the  rate of evaporation
from the process tank.  The evaporation from  a bath is  a  function
of its temperature, surface area, and ventillation rate,  while  the
overflow rate is dependent on the dilution ratio, the geometry  of
the part, and the dragout rates.  If the  rinse is noncritical,  i.e.,
where the part is going to another finishing  operation, closing the
loop (returning rinse overflow to the process tank) can be  accom-
plished with far fewer rinse tanks than a critical rinse  (follow-
ing the last process operation).  For example, if a particular
line is always used to plate base metals  only, and afterwards  the
work always goes to another process, then this permits  a  lower
flow rate with consequently higher buildup of pollutants  in the
rinse.  Under these conditions, an external concentrator, such  as
an evaporator, is not required, and the rinse overflow  can  be used
directly for process bath makeup.  The reverse is often true with
the rinse following the final finishing step.  The flow rate in
this instance may be high enough that it exceeds the bath evapor-
ation rate and some form of concentrator  is required.

When using any rinse arrangement for makeup of evaporative  losses
from a process solution, the quality of the rinse water must be
known and carefully monitored.  Naturally occurring dissolved
solids such as calcium and magnesium salts can slowly build up  and
cause the process to go out of control.  Even using softened water
can cause process control problems.  For this reason, deionized
water is often used as a feed for rinsing arrangements which will
be used for evaporative makeup of process solutions.

Oily Waste Segregation

Many different types (or compounds) of oils and related fluids  are
common in oily wastes and include cutting oils, fluids, lubricants,
greases, solvents, and hydraulic fluids.  Segregation of  these  oily
wastes from other wastewaters reduces the expense of both the waste-
water treatment and the oil recovery process by minimizing  the  quan-
tity and number of constituents involved.  In addition, segregated
oily wastes are appropriate for hauling to disposal/reclamation by
a contractor in lieu of on-site treatment.  Additional segregation
of oily wastes by type or compound can further reduce treatment or
hauling costs.  Some oils have high reclaimer values and are more
desirable if they are not contaminated by other oils.

Properly segregated spent oils containing common base oils  and
additives will retain much more of their original value and can be
efficiently processed.  Spent oils, properly segregated, can be
reprocessed in-house oc sold to an outside contractor.  Some plants
purchase reprocessed oils which results in substantial savings.

The true value of oils and cutting fluids should be realized during
its entire use cycle, from purchase to disposal and reuse.   This is
particularly true during used oil collection and storage.
                               VEI-264

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Process Bath Segregation

Process baths which are to be sent to waste treatment rather  than
being shipped out should be segregated from one another.  The pur-
pose of this is the same as for segregating raw waste streams.
Mixing together of process solutions may form compounds which are
very difficult to treat or create unnecessarily larger volumes of
water requiring specialized treatment such as chromium reduction
or cyanide oxidation.

Process Modification

Process modifications can reduce the amount of water required for
rinsing or reduce the load of certain pollutants on a waste treat-
ment facility.  For example, a rinse step can be eliminated in
electroless plating by using a combined sensitization and activa-
tion solution followed by a rinse in place of a process sequence
of sensitization-rinse-activation-rinse.  Another potential pro-
cess modification would be to change from a high concentration
plating bath to one with a lower concentration.  Parts plated
in the lower concentration bath require less rinsing (a dilution
operation) and, thus, decrease the water usage relative to high
concentration baths.

There are also constantly increasing numbers of substitute bath
solutions and plating processes becoming commercially available.
A number of these are listed below:

     Non-chromic acid pickling solutions
     Non-cyanide zinc and copper plating
     Non-aqueous plating processes
     Trivalent chromium plating
     Etch recovery and recirculating systems
     Non-chromium decorative plating
     Substitutions for cadmium where applicable
     Phosphate-free and biodegradable cleaners

These options have been formulated in an effort to reduce the level
of critical pollutants generated.

For plants which are currently using spraying as their painting
application method, there are several alternative methods of appli-
cation which could reduce the amount of wastewater generated by the
painting operation.  Among these methods are electrostatic spraying,
powder coating, flow coating and dip coating.  Electrostatic spray-
ing has a smaller percent of overspray so less paint enters into
the wastewater stream.  Powder coating, flow coating and dip coating
generate no wastewater and the powders or paints used can be re-
cycled.  The selection of an application method is highly dependent
upon the geometry of the part being painted so not all of the
methods mentioned above will work for a specific work piece.
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A plant which has a painting operation and employs water wash  spray
booths to capture overspray may reduce its pollutant generation  by
modifications to the spray booths.  One possibility is switching
over to dry filter booths or oil wash booths.  Neither of these
produces any wastewater.  Another alternative is improving  the
existing booths by adding automatic screening or electrostatic
treatment.  Both of these features continuously remove paint
solids from the water and allow for less frequent dumps of  the
booth water, thereby reducing wastewater generation.

Another process modification applicable to metal finishing  plants
is the replacement of solvent degreasing, where possible, with an
alternative cleaning method such as alkaline cleaning,  typical
areas that are amenable to cleaning techniques other than solvent
degreasing are:

     1.   Low to medium volume production levels when cleaning
          cycle time does not impact the cost of production.

     2.   Non-ferrous products.

     3.   Simple product shapes

     4.   Small parts (adaptable to automated processes)

     5.   Situations where an oily film residue is not
          objectionable.

     6.   Situations where no exacting surface finishing
          is required.

Essential to efficient maching operations is a clean and effi-
cient cutting fluid cleaning system.  An efficient cleaning sys-
tem allows for recycling and reuse of oils.  In maintaining clean
fluid, the operation, the metal, and the fluid must be considered.
Settling and skimming is only efficient when large volumes  of
fluid and long retention times are available.  When fine parti-
cles or micro-debris are involved, the cleaning or maintenance of a
cutting fluid also depends on whether it is a straight oil  or an
aqueous dilution.  The operation and the metal used will produce
coarse debris while brittle metals produce fine debris requiring
a more sophisticated type of treatment.  Filtration, centrifuging,
or magnetic separation may be necessary.

Straining - Oil or water solutions require straining to ensure
pump protection.  Double strainers should be inserted and kept free
of rags, lint, or other clogging elements.  Stainless mesh  strain-
ers are recommended for aqueous systems to minimize corrosion.
                               VI1-266

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Settling - Large sumps or central systems permit settling.  Par-
ticle size and retention time are important considerations to en-
sure debris or sediment removal.  Settling is essential to other
methods of fluid cleaning by helping reduce sediment loads on
filters and centrifuges.

Baffles above and below the surface of the fluid level will im-
prove settling and deposition.  Tramp oils, scums, and soaps
may be skimmed either continuously or intermittently.  Dense
debris and sediment can be removed by drag chains, periodic
sump clean out, scum gutters, or surface paddles and sweeps.

Centrifuging - As an accelerated settling process, the centri-
fugeTslargely limited to low solids content removal.  It may
be used to enhance the efficiency of low volume systems and
will remove fine particles.

Magnetic Separators - Magnetic separators are an effective
means of removing ferrous or magnetic metals and are most effi-
ciently used with low viscosity fluids or aqueous systems.

Filtration - The pore size or opening of a filter media will
determine the particle size which may be removed.  The most com-
mon filtering systems consist of self-advancing rolled fabric.
Filtration may be enhanced by vacuum or negative pressure.
Supplemental coatings on filter media, such as diatomaceous
earth, add depth to area filtration.

Flotation - The cleaning of cutting fluids can utilize the
aeration process which causes fine particles to attach themselves
to air bubbles, producing an efficient flotation system.  Floating
matter, foam, and scum are then removed by continuous skimmers or
froth paddles.  Flotation by aeration has the advantage of high
solids removal in relation to liquid losses and effectively con-
serves coolant.  In general, the flotation-type system works best
with emulsifiable-type coolants but foam must be controlled.
This system cannot be used with water miscible fluids of high
wettability.

Integrated Waste Treatment

Waste treatment can be accomplished in the production area with
constant recycling of the effluent.  This process is generally
known as integrated waste treatment.  Integrated waste treatment
can be applied to oily wash waters and electroplating rinse waters
                                VII-267

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The washing of oily metal parts, rinses following oil quenches,
machine system leaks, and some testing washes or rinses produce
the largest majority of oily wastewater.  Steps should be taken
in-plant to segregate cutting fluids, hydraulic oils, crankcase
oil, quench oils, and solvents from these waste streams.

Closed loop systems are available for removing oils, metal
fines, and other residues from wash water through a combination
of settling and skimming.  A typical closed loop system consists
of two compartments holding caustic wash solution, each equipped
with an oil roll skimmer.  While one compartment supplies wash
solution to a series of washers, the other remains dormant, allow-
ing heavy material to settle and oils float to the surface.  The
solids are collected as sludge and the oils are skimmed off.  An
alternative system would be an ultrafiltration system which can
recycle water back to rinse and wash make-up stations.

Integrated treatment for plating processes uses a treatment rinse
tank in the process line immediately following a process tank
(plating, chromating, etc).  Treatment solution (usually caustic
soda in excess) circulating through the rinse tank reacts with
the dragout to form a precipitate and removes it to a clarifier.
This clarifier is a small reservoir usually designed to fit near
the treatment rinse tank and be an integral part of water use in
the production process.  Further treatment may take place in the
clarifier (cyanide oxidation, chromium reduction) or settling alone
may be used to separate the solids.  Sludge is removed near the
spillover plate on the effluent side of the clarifier, and the
effluent is returned to the treatment rinse tank.  Consequently,
no pollutants are directly discharged by the waste treatment pro-
cess.  Although further rinsing of the parts is required to remove
treatment chemicals, this rinse will not contain pollutants from
the original process tank, and no further treatment is needed.

Good Housekeeping

Good housekeeping, proper selection and handling of process solu-
tions, and proper maintenance of metal finishing equipment are re-
quired to reduce wastewater loads to the treatment system.  Good
housekeeping techniques prevent premature or unnecessary dumps of
process solutions and cooling oils.  Examples of good housekeeping
are discussed below.

          Frequent inspection of plating racks for loose insulation
          prevents excessive dragout of process solutions.  Also,
          periodic inspection of the condition of tank liners and
          the tanks themselves reduces the chance of a catastrophic
          failure which would overload the treatment system.
                               VTI-268

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Steps should be taken to prevent the formation of hard-to-
treat wastes.  Separation of cyanide wastes from nickel or
iron wastes is advisable to avoid formation of cyanide
complexes.  Proper tank linings in steel tanks prevent  the
formation of ferrocyanides.

Periodic inspection should be performed on all auxiliary
metal finishing equipment.  This includes inspection of
sumps, filters, process piping, and immersion steam heat-
ing coils for leaks.  Filter replacement should be done in
curbed areas or in a manner such that solution retained by
the filter is dumped to the appropriate waste stream.

Chemical storage areas should be isolated from high hazard
fire areas and arranged such that if a fire or explosion
occurs in the storage area, loss of the stored chemicals
due to deluge quantities of water would not overwhelm the
treatment facilities.

Bacterial buildup on machines, sump walls and circulatory
systems should be sterilized at regular intervals.  Cen-
tralized cooling systems are self-cleaning to some extent,
but physical and biological cleaning are required.  The
physical cleaning entails the removal of metallic fines,
oxidized oil and other sludge forming matter.  Biological
cleaning involves the use of antiseptic agents, detergents
and germicides.

Chip removal from machining operations should include oil
recovery and salvage provisions.

A lubrication program schedule keeps track of leakage and
contamination.  By analyzing records of consumption, it is
possible to identify high consumption equipment.  Premature
drain intervals may indicate abnormal system contamination
which should be corrected.

A general accounting of oils and fluids throughout their
life cycle (purchasing, storage, application, cleaning
and disposal)  will lead to oil and fluid conservation.

It is important that proper lubricants should be employed
in a particular piece of machinery.  Marking each piece of
equipment with the product type requires is practiced
throughout the industry.  This helps prevent the use of an
improper oil and the subsequent premature dumping of that
oil.

Training and educating the operators of production equip-
ment and waste treatment equipment can prevent unnecessary
waste.
                        VII-269

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                        SECTION  VIII
         COST OF WASTEWATER  CONTROL AND TREATMENT
INTRODUCTION

This section presents estimates of the cost of implementation  of
wastewater treatment and control options for each of  the
subcategories included in the Metal Finishing Category.  These  cost
estimates, together with the pollutant reduction performance es-
timates for each treatment and control option presented in  Sec-
tion VII provide a basis for evaluation of the options presented.
The cost estimates also provide the basis for the determination
of the probable economic impact of regulation at different  pol-
lutant discharge levels on the Metal Finishing Category.  In ad-
dition, this section addresses non-water quality environmental
impacts of wastewater treatment and control options including
air pollution,  noise pollution, solid wastes, and energy require-
ments.

To arrive at the cost estimates presented in this section,
specific wastewater treatment technologies and in-process
control techniques from among those discussed in Section VII
were selected and combined in wastewater treatment and control
systems appropriate for each subcategory.  As described in  more
detail below, investment and annual costs for each system were
estimated based on wastewater flow rates and raw waste character-
istics for each subcategory as presented in Section V.  Cost
estimates are also presented for individual treatment technologies
included in the waste treatment systems.

COST ESTIMATION METHODOLOGY

Cost estimation is accomplished using a computer program which
accepts inputs  specifying the treatment system to be  estimated,
chemical characteristics of the raw waste streams treated,  flow
rates and operating schedules.  The program accesses  models for
specific treatment components which relate component  investment
and operating costs, materials and energy requirements, and
effluent stream characteristics to influent flow rates and  stream
characteristics-.  Component models are exercised sequentially
as the components are encountered in the system to determine
chemical characteristics and flow rates at each point.  Component
investment and  annual costs are also determined and used in the
computation of  total system costs.  Mass balance calculations
are used to determine the characteristics of combined streams
                              Vlli-l

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resulting from mixing two or more streams and to determine
the volume of sludges or liquid wastes resulting from treatment
operations such as sedimentation, filtration, flotation, and
oil separation.

Cost estimates are broken down into several distinct elements
in addition to total investment and annual costs:  operation
and maintenance costs, energy costs, depreciation, and  annual
costs of capital.  The cost estimation program incorporates
provisions for adjustment of all costs to a common dollar base
on the basis of economic indices appropriate to capital  equipment
and operating supplies.  Labor and electrical power unit costs ace
input variables appropriate to the dollar base year for  cost
estimates.  These cost breakdown and adjustment factors  as well
as other aspects of the cost estimation process are discussed
in greater detail in the following paragraphs.

Cost Estimation Input Data

The waste treatment system descriptions input to the computer
cost estimation program include both a specification of  the
waste treatment components included and a definition of  their
interconnections.  For some components, retention times  or other
operating parameters are specified in the input, while  for others,
such as reagent mix tanks and clarifiers, these parameters are
specified within the program based on prevailing design  practice
in industrial waste treatment.  The waste treatment system des-
criptions may include multiple raw waste stream inputs  and mul-
tiple treatment trains.  For example, cyanide bearing waste
streams are segregated and treated for cyanide oxidation and
chromium bearing wastes for chromium reduction prior to  subse-
quent chemical precipitation treatment with the remaining process
wastewater.

The specific treatment systems selected for cost estimation for
each subcategory were based on an examination of raw waste
characteristics, consideration of manufacturing processes, and
an evaluation of available treatment technologies discussed in
Section VII.  The rationale for selection of these systems is also
presented in Section VII where pollution removal effectiveness
is also addressed.

The input data set also includes chemical characteristics for
each raw waste stream specified as input to the treatment systems
for which costs are to be estimated.  These characteristics are
derived from the raw waste sampling data presented in Section
V.  The pollutant parameters which are presently accepted as
input by the cost estimation program are shown in Table  8-1.
The values of these parameters are used in determining  materials
consumption, sludge volumes, treatment component sizes  and effluent
                              VIII-2

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                        TABLE 8-1

             COST PROGRAM POLLUTANT PARAMETERS
Parameter,  Units

Flow,  MGD
pH, pH units
Turbidity,  Jackson Units
Temperature, degree C
Dissolved Oxygen,  mg/1
Residual Chlorine, mg/1
Acidity, mg/1 CaCO
Alkalinity, mg/1 CaC03
Ammonia, mg/1
Biochemical Oxygen Demand mg/1
Color, Chloroplatinate units
Sulfide, mg/1
Cyanides, mg/1
Kjeldahl Nitrogen, mg/1
Phenols, mg/1
Conductance, micromhos/cm
Total  Solids, mg/1
Total  Suspended Solids, mg/1
Settleable Solids, mg/1
Aluminum, mg/1
Barium, mg/1
Cadmium, mg/1
Calcium, mg/1
Chromium, Total, mg/1
Copper, mg/1
Fluoride, mg/1
Iron,  Total, mg/1
Lead,  mg/1
Magnesium,  mg/1
Molybdenum, mg/1
Total  Volatile Solids, mg/1
Parameter, Units

Oil, Grease, mg/1
Hardness, mg/1 CaCO
Chemical Oxygen Demand, mg/1
Algicides, mg/1
Total Phosphates, mg/1
Polychlorobiphenyls, mg/1
Potassium, mg/1
Silica, mg/1
Sodium, mg/1
Sulfate, mg/1
Sulfite, mg/1
Titanium, mg/1
Zinc, mg/1
Arsenic, mg/1
Boron, mg/1
Iron, Dissolved, mg/1
Mercury, mg/1
Nickel, mg/1
Nitrate, mg/1
Selenium, mg/1
Silver, mg/1
Strontium, mg/1
Surfactants, mg/1
Beryllium, mg/1
Plasticizers, mg/1
Antimony, mg/1
Bromide, mg/1
Cobalt, mg/1
Thallium, mg/1
Tin, mg/1
Chromium, Hexavalent, mg/1
                              VIII-3

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characteristics.  The list of input parameters  is  expanded
periodically as additional pollutants are  found  to be  significant
in waste streams from industries under study  and as  additional
treatment technology cost and performance  data  become  available.
Within the Metal Finishing Category, individual  subcategories
commonly encompass a number of different waste  streams  which  are
present to varying degrees at different facilities.  The  raw  waste
characteristics shown as input to waste treatment  represent a mix of
these streams including all significant pollutants generated  in
the subcategory and will not in general correspond precisely  to
process wastewater at any existing facility.  The  process  by
which these raw wastes were defined is explained in  Section V.

The final input data set comprises raw waste  flow  rates  for each
subcategory input stream addressed.  Cases are  shown for  typical
plants hauling all their wastewater, for plants whose  flow makes
batch treatment the most viable option and for  plants  with flow
rates sufficiently high to warrant a continuous  treatment  system
with the appropriate automatic controls. From these  data,  graphs
have been prepared showing total annual costs for  the  range of
flows encountered in the Metal Finishing Category  data  base
(363 to 3,785,000 liters/day).

System Cost Computation

A simplified flow chart for the estimation of wastewater
treatment and control costs from the input data described
above is presented in Figure 8-1.  In the  computation,  raw
waste characteristics and flow rates for the  first case  are
used as input to the model for the first treatment technology
specified in the system definition.  This  model  is used  to
determine the size and cost of the component, materials  and
energy consumed in its operation, and the  volume and character-
istics of the stream(s) discharged from it.  These stream
characteristics are then used as input to  the next cornponent(s)
encountered in the system definition.  This procedure  is
continued until the complete system costs  and the  volume  and
characteristics of the final effluent stream(s) and  sludge or
concentrated oil wastes have been determined.   In  addition to
treatment components, the system may include mixers  in  which
two streams are combined, and splitters in which part  of  a stream
is directed to another destination.  These elements  are  handled
by mass balance calculations and allow cost estimation  for
specific treatment of segregated process wastes  such as
oxidation of cyanide bearing wastes prior  to  combination  with
other process wastes for further treatment, and  representation
of partial recycle of wastewater.
                               VIII-4

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                          FIGURE  8-1

                  SIMPLIFIED  LOGIC DIAGRAM

                SYSTEM COST ESTIMATION PROGRAM
NON-RECYCLE
  SYSTEMS
                 INPUT
                 A)  RAW WASTE DESCRIPTION
                 B)  SYSTEM DESCRIPTION
                 C)  'DECISION" PARAMETERS
                 D)  COST FACTORS
                 PROCESS CALCULATIONS
                 A)   PERFORMANCE -  POLLUTANT
                     PARAMETER EFFECTS
                 B)   EQUIPMENT SIZE
                 C)   PROCESS  COST
                              (RECYCLE SYSTEMS)
CONVERGENCE
A)  POLLUTANT PARAMETER
    TOLERANCE CHECK
                                (NOT WITHIN

                                 TOLERANCE  LIMITS)
                              (WITHIN  TOLERANCE  LIMITS)
                 COST  CALCULATIONS
                 A)  SUM  INDIVIDUAL  PROCESS
                    COSTS
                 B)  ADD  SUBSIDIARY  COSTS
                 C)  ADJUST  TO  DESIRED  DOLLAR
                    BASE
                OUTPUT
                A)  STREAM DESCRIPTIONS -
                    COMPLETE SYSTEM
                B)  INDIVIDUAL PROCESS SIZE
                    AND COSTS
                C)  OVERALL SYSTEM INVESTMENT
                    AND ANNUAL COSTS
                              VIII-5

-------
As an example of this computation process,  the  sequence  of
calculations involved in the development of  cost  estimates
for the simple treatment system shown  in Figure 8-2  may  be
described.  Initially, input specifications  for the  treatment
system are read to set up the sequence of  computations.   The
subroutine addressing chemical precipitation and  clarification
is then accessed.  The sizes of the mixing  tank and  clarification
basin are calculated based on the raw  waste  flow  rate  to provide
45 minute retention in the mix tank and 4  hour  retention with
33.3 gph/ft  surface loading in the clarifier.  Based  on these
sizes, investment and annual costs for labor, supplies for
the mixing tank and clarifier including mixers, clarifier
rakes and other directly related equipment  are  determined.
Fixed investment costs are then added  to account  for sludge
pumps, controls and reagent feed systems.

Based on the input raw waste concentrations  and flow rates,
the reagent additions (lime, alum, and polyelectrolyte)  are
calculated to provide fixed concentrations  of alum and poly-
electrolyte and 10% excess lime over that  required for
stoichiometric reaction with the acidity and metals  present
in the waste stream.  Costs are calculated  for  these materials,
and the suspended solids and flow leaving  the mixing tank and
entering the clarifier are increased to reflect the  lime solids
added and precipitates formed.  These  modified  stream  character-
istics are then used with performance  algorithms  for the clarifier
(as discussed in Section VII) to determine  concentrations of
each pollutant in the clarifier effluent stream.  By mass balance,
the amount of each pollutant in the clarifier sludge may be
determined.  The volume of the sludge  stream is determined  by
the concentration of TSS, which is fixed at  4.5%  based on
general operating experience.  Concentrations of  other pollutants
in the sludge stream are determined from their  masses  and the
volume of the stream.

The subroutine describing vacuum filtration  is  then  called,
and the mass of suspended solids in the clarifier sludge stream
is used to determine the size and investment cost of the vacuum
filtration unit.  Operating hours for  the  filter  are calculated
from the flow rate and TSS concentration and the  manhours required
for operation are determined.  Maintenance  labor  requirements are
added as a fixed additional cost.

The sludge flow rate and TSS content are then used to  determine
costs of materials and supplies for vacuum filter operation
including iron and alum added as filter aids and  the electrical
power costs for operation.  Finally, the vacuum filter performance
algorithms are used to determine the volume  and characteristics
of the vacuum filter sludge and filtrate,  and the costs  of
contract disposal of the sludge are calculated.   The recycle of
                              VIII-6

-------
               Lime   Flocculant
Raw Waste
 Flow
 TSS
 Pb
 Zn
 Acidity
Chemical
Addition
Mixing
t



Clarif ier

Filtrate
*
Vacuum
Filter

Effluent
                                      T
                             Sludge Contractor Removed
                         FIGURE 8-2
               SIMPLE WASTX  TREATMENT SYSTEM
                       VIII-7

-------
vacuum filter filtrate to the chemical precipitation-clarification
system is not reflected in the calculations due  to  the  difficulty
of iterative solution of such loops and  the general  observation
that the contributions of such streams to  the  total  flow  and
pollutant levels are in practice, negligibly small.  Allowance
for such minor contributions is made  in  the 20%  excess  capacity
provided in most components.

The costs determined for all components  of the system are
summed and subsidiary costs are added to provide  output specifying
total investment for the system and annual costs  for capital,
depreciation, operation and maintenance, and energy.  Costs
fror specific system components and the characteristics  of all
streams may also be specified as output  from the  program.

Treatment Component Models

The cost estimation program presently incorporates  subroutines
providing cost and performance calculations for  the  treatment
technologies identified in Table 8-2.  These subroutines  have
been developed over a period of years from the best  available
information including on-site observations of  treatment system
performance, costs, and construction practices at industrial
facilities, published data, and information obtained from
suppliers of wastewater treatment equipment.  The subroutines
are modified and new subroutines added as  additional data allow
improvements in the treatment technologies already  modelled
and as additional treatment technologies are required for the
industrial wastewater streams under study.  Specific discussion
of each of the treatment component models  used in costing waste-
water treatment and control systems for  the Metal Finishing
Category is presented later in this section where cost  estima-
tion is addressed, and in Section VII where performance aspects
were developed.

In general terms, cost estimation is provided  by  mathematical
relationships in each subroutine approximating observed
correlations between component costs and the most significant
operational parameters such as water flow  rate,  retention times,
and pollutant concentrations.  In general, flow  rate is the
primary determinant of investment costs  and of most  annual
costs with the exception of materials costs.   In  some cases,
however, as discussed above for the vacuum filter,  pollutant
concentrations may also significantly influence  costs.

Cost Factors and Adjustments

As previously indicated, costs are adjusted to a  common dollar
base and are generally influenced by a number of  factors  including:
Cost of Labor, Cost of Energy, Capital Recovery  Costs and
Debt-Equity Ratio.  These cost adjustments and factors  are
discussed below.
                              VIII-8

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                                 TABLE 8-2

                         TREATMENT TECHNOLOGY SUBROUTINES

               Treatment Process Subroutines Presently Available
Spray/Fog Rinse
Countercurrent Rinse
Vacuum Filtration
Gravity Thickening
Sludge Drying Beds
Holding Tanks
Centrifugation
Equalization
Contractor Removal
Reverse Osmosis
Landfill
Chemical Reduction of Chrom.
Chemical Oxidation of Cyanide
Neutralization
Clarification (Settling Tank/Tube Settler)
API Oil Skimming
Emulsion Breaking (Chem/Thermal)
Membrane Filtration
Filtration (Diatomaceous Earth)
Ion Exchange - w/Plant Regeneration
Ion Exchange - Service Regeneration
Flash Evaporation
Climbing Film Evaporation
Atmospheric Evaporation
Cyclic Ion Exchange
Post Aeration
Sludge Pumping
Copper Cementation
Flouride Removal (By lime addition)
Sanitary Sewer Discharge Fee
Ultrafiltration
Submerged Tube Evaporation
Flotat ion/Separation
Wiped Film Evaporation
Trickling Filter
Activated Carbon Adsorption
Nickel Filter
Sulfide Precipitation
Sand Filter
Chromium Regeneration
Pressure Filter
Multimedia Granular Filter
Sump
Cooling Tower
Ozonation
Activated Sludge
Coalescing Oil Separator
Non Contact Cooling Basin

Raw Wastewater Pumping
Preliminary Treatment
Preliminary Sedimentation
Aerator - Final Settler
Chlorination
Flotation Thickening
Multiple Hearth Incineration
Aerobic Digestion
     Treatment Process Subroutines Currently Being Developed

     Peroxide Oxidation
     Air Stripping (Ammonia Removal)
     Arsenic Removal
     Water Recycle or Reuse
                                    VIII-9

-------
Dollar Base - A dollar base of August 1979 was used for all  costs.

Investment Cost Adjustment - Investment costs were adjusted  to
the aforementioned dollar base by use of the Sewage Treatment
Plant Construction Cost Index.  This index is published quarterly
by the EPA Division of Facilities Construction and Operation.
The national average of the Construction Cost Index for August
1979 was 337.8.

Supply Cost Adjustment - Supply costs such as chemicals were re-
lated to the dollar base by the Producer Price Index.  This  figure
was obtained from the U.S. Department of Labor, Bureau of Labor
Statistics, "Monthly Labor Review".  For August 1979 the
"Industrial Commodities" Producer Price Index was 240.3.  Process
supply and replacement costs were included in the estimate of
the total process operating and maintenance cost.

Cost of Labor - To relate the operating and maintenance labor costs,
the hourly wage rate for non-supervisory workers in sanitary
services was used from the U.S. Department of Labor, Bureau  of
Labor Statistics Monthly publication, "Employment and Earnings".
For August 1979, this wage rate was $6.71 per hour.  This wage
rate was then applied to estimates of operation and maintenance
man-hours within each process to obtain process direct labor
charges.  To account for indirect labor charges, 15 percent  of
the direct labor costs was added to the direct labor charge  to
yield estimated total labor costs.  Such items as Social Security,
employer contributions to pension or retirement funds, and
employer-paid premiums to various forms of insurance programs
were considered indirect labor costs.

Cost of Energy - Energy requirements were calculated directly
within each process.  Estimated costs were then determined by
applying an electrical rate of 4.5 cents per kilowatt hour.

Capital Recovery Costs - Capital recovery costs were divided
into straight line five depreciation and cost of capital
at a thirteen percent annual interest rate for a period of five
years.  The five year depreciation period was consistent with the
faster write-off (financial life) allowed for these facilities
even though the equipment life is in the range of 20 to 25 years.
                              VIII-10

-------
The annual cost of capital was calculated by  using  the  capital
recovery factor approach.

The capital recovery factor is normally used  in  industry  to
help allocate the initial investment and the  interest  to  the
total operating cost of  the facility.  It is  equal  to:

                         i +      i
where i is the annual interest rate and N  is  the  number  of
years over which the capital is to be recovered.  The  annual
capital recovery was obtained by multiplying  the  initial
investment by the capital recovery factor.  The annual deprecia-
tion of the capital investment was calculated by  dividing the
initial investment by the depreciation period N,  which was
assumed to be five years.  The annual cost of capital was then
equal to the annual capital recovery minus the depreciation.

Debt-Equity Ratio - Limitations on new borrowings assume that debt
may not exceed a set percentage of the shareholders equity.  This
defines the breakdown of: the capital investment between  debt
and equity charges.  However, due to the lack of  information
about the financial status of various plants, it  was not
feasible to estimate typical shareholders  equity  to obtain
debt financing limitations.  For these reasons, no attempt was
made to break down the capital cost into debt and equity charges.
Rather, the annual cost of capital was calculated via  the
procedure outlined in the Capital Recovery Costs  section above.

Subsidiary Costs

The waste treatment and control system costs presented in Figures
8-28 through 8-44 for end-of-pipe and in-process  wastewater control
and treatment systems include subsidiary costs associated with
system construction and operation.  These  subsidiary costs include:

          administration and laboratory facilities

          garage and shop facilities

          line segregation

          yardwork

          land

          engineering

          legal, fiscal, and administrative

          interest during construction
                         VIII-11

-------
Administrative and laboratory facility treatment  investment
is the cost of constructing space for administration,  laboratory,
and service functions for the waste water treatment  system.
For these cost computations, it was assumed that  there was
already an existing building and space for administration,
laboratory, and service functions.  Therefore,  there was  no
investment cost for this item.

For laboratory operations, an analytical fee of $105  (August  1979
dollars) was charged for each wastewater sample,  regardless of
whether the laboratory work was done on or off  site.   This
analytical fee is typical of the charges experienced by Hamilton
Standard during the past several years of sampling programs.
The frequency of waste water sampling is a function  of waste
water discharge flow and is presented in Table  8-3.  This
frequency was suggested by the Water Compliance Division  of
the USEPA.

For industrial waste treatment facilities being costed, no
garage and shop investment cost was included.   This  cost  item
was assumed to be part of the normal plant costs  and was  not
allocated to the wastewater treatment system.

Line segregation investment costs account for plant  modifications
to segregate wastes.  The investment costs for  line  segregation
included placing a trench in the existing plant floor  and installing
the lines in this trench.  The same trench was  used  for all pipes
and a gravity feed to the treatment system was  assumed.   The
pipe was assumed to run from the center of the  floor to a corner.
A rate of 2.04 liters per hour of waste water discharge per
square meter of area (0.05 gallons per hour per square foot)
was used to determine floor and trench dimensions from waste
water flow rates for use in this cost estimation  process.

The yardwork investment cost item includes the  cost  of general site
clearing, intercomponent piping, valves, overhead and  underground
electrical wiring, cable, lighting, control structures, manholes,
tunnels, conduits, and general site items outside the  structural
confines of particular individual plant components.  This cost is
typically 9 to 18 percent of the installed components  investment
costs.  For these cost estimates, an average of 14 percent was
utilized.  Annual yardwork operation and maintenance costs are
considered a part of normal plant maintenance and were not
included in these cost estimates.

No new land purchases were required.  It was assumed that the
land required for the end-of-pipe treatment system was already
available at the plant.

Engineering costs include both basic and special  services.  Basic
services include preliminary design reports, detailed  design, and
                              VIII-12

-------
                        TABLE 8-3

               WASTE WATER SAMPLING FREQUENCY
Waste Water Discharge
   (liters per day)

      0 -  37,850

 37,850 - 189,250

189,250 - 378,500

378,500 - 946,250

946,250+
Sampling Frequency

once per month

twice per month

once per month

twice per week

thrice per week
                              VIII-13

-------
certain office and field engineering services during construction
of projects.  Special services include improvement studies,
resident engineering, soils investigations, land surveys,
operation and maintenance manuals, and other miscellaneous
services.  Engineering cost is a function of process installed
and yardwork investment costs and ranges between 5.7 and
14% depending on the total of these costs.

Legal, fiscal and administrative costs relate to planning and
construction of waste water treatment facilities and include
such items as preparation of legal documents, preparation of
construction contracts, acquisition to land, etc.  These costs
are a function of process installed, yardwork, engineering, and
land investment costs ranging between 1 and 3% of the  total
of these costs.

Interest cost during construction is the interest accrued on
funds from the time payment is made to the contractor  to the
end of the construction period.  The total of all other project
investment costs (process installed; yardwork; land; engineering;
and legal, fiscal, and administrative) and the applied interest
affect this cost.  An interest rate of 10 percent was  used to
determine the interest cost for these estimates.  In general,
interest cost during construction varies between 3 and 10% of
total system costs depending on the total costs.

COST ESTIMATES FOR INDIVIDUAL TREATMENT TECHNOLOGIES

Introduction

Table 8-4 lists those technologies which are incorporated
in the wastewater treatment and control options offered for the
Metal Finishing Category and for which cost estimates  have been
developed.  These treatment technologies have been selected
from among the larger set of available alternatives discussed
in Section VII on the basis of an evaluation of raw waste
characteristics, typical plant characteristics (e.g. location,
production schedules, product mix, and land availability), and
present treatment practices within the subcategories addressed.
Specific rationale for selection is addressed in Sections IX, X,
XI and XII.  Cost estimates for each technology addressed in this
section include investment costs and annual costs for  depreciation,
capital, operation and maintenance, and energy.

Investment - Investment is the capital expenditure required to
bring the technology into operation.  If the installation is a
package contract, the investment is the purchase price of the
installed equipment.  Otherwise, it includes the equipment cost,
cost of freight, insurance and taxes, and installation costs.
                            VIII-14

-------
                   TABLE 8-4
            INDEX TO TECHNOLOGY COSTS
  Technology
 Figure on Table
CN Oxidation
Chromium Reduction
Clarification
Holding Tanks
Emulsion Breaking
Multimedia Filtration
Ultrafiltration
Carbon Adsoption
Sludge Drying Beds
Countercurrent Rinse
Evaporation
Figures
Figures
Figures
Figures
Figures
Figures
Figures
Figures
Figures
Tables
Figure
to
&
to
8-3
8-6
8-8
8-10 to
8-13 &
8-15 &
8-17 &
8-19 to
8-22 to
8-6  &
8-26
8-5
8-7
8-9
8-12
8-14
8-16
8-18
8-21
8-25
8-7
                        VIII-15

-------
Total Annual Cost - Total annual cost  is  the  sum of  annual  costs
for depreciation, capital, operation and  maintenance (less  energy),
and energy (as a separate function).

     Depreciation - Depreciation is an allowance,  based  on  tax
     regulations, for the recovery of  fixed capital  from an in-
     vestment to be considered as a non-cash  annual  expense.   It
     may be regarded as the decline in value  of a  capital asset
     due to wearout and obsolescence.

     Capital - The annual cost of capital  is  the cost,  to the
     plant, of obtaining capital expressed as an interest rate.
     It is equal to the capital recovery  cost (as  previously dis-
     cussed on cost factors) less depreciation.

     Operation and Maintenance - Operation and maintenance  cost
     is the annual cost of running the waste  water treatment
     equipment.  It includes labor and materials such  as waste
     treatment chemicals.  As presented on the tables,  operation
     and maintenance cost does not include energy  (power or fuel)
     costs because these costs are shown  separately.

     Energy - The annual cost of energy is shown separately,
     although it is commonly included as  part of operation  and
     maintenance cost.  Energy cost has been  shown separately
     because of its importance to the nation's economy  and  natural
     resources.

Cyanide Oxidation

In this technology, cyanide is destroyed  by reaction with sodium
hypochlorite under alkaline conditions.   A complete  system  for
accomplishing this operation includes reactors,  sensors, controls,
mixers, and chemical feed equipment.  Control of both  pH and
chlorine concentration (through oxidation-reduction  potential)
is important for effective treatment.

Investment Costs.  Investment costs for cyanide oxidation as
shown in Figure 8-3 include reaction tanks, reagent  storage,
mixers, sensors and controls necessary for operation.  Costs are
estimated for both batch and continuous systems with the operating
mode selected on a least cost basis.   Specific costing  assump-
tions are as follows:

For both continuous and batch treatment,  the  cyanide oxidation
tank is sized as an above ground cylindrical  tank  with  a retention
time of 4 hours based on the process flow.  Cyanide  oxidation
is normally done on a batch basis; therefore, two  identical tanks
are employed.
                             VIII-16

-------
     10'
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-------
Cyanide oxidation is accomplished by the addition  of  sodium hypo-
chlorite.  Sodium hydroxide is added to maintain the  proper pH
level.  A 60 day supply of sodium hypochlorite  is  stored  in an
in-ground covered concrete tank, 0.305 m (1 ft) thick.  A 90
day supply of sodium hydroxide is also stored in an  in-ground
covered concrete tank, 0.305 m (1 ft) thick.

Mixer power requirements for both continuous and batch  treatment
are based on 2 horsepower for every 11,355 liters  (3,000  gal)
of tank volume.  The mixer is assumed to be operational 25  percent
of the time that the treatment system is operating.

A continuous control system is costed for the continuous  treatment
alternative.  This system includes:

     2    immersion pH probes and transmitters
     2    immersion ORP probes and transmitters
     2    pH and ORP monitors
     2    2-pen recorders
     2    slow process controller
     2    proportional sodium hypochlorite pumps
     2    proportional sodium hydroxide pumps
     2    mixers
     3    transfer pumps
     1    maintenance kit
     2    liquid level controllers and alarms,  and miscellaneous
          electrical equipment and piping

A complete manual control system is costed for  the batch  treatment
alternative.  This system includes:

     2    pH probes and monitors
     1    mixer
     1    liquid level controller and horn
     1    proportional sodium hypochlorite pump
     1    on-off sodium hydroxide pump and PVC  piping from  the
          chemical storage tanks

Operation and Maintenance Cost.  Operation and  maintenance  costs
for cyanide oxidation include labor requirements to  operate and
maintain the system, electric power for mixers, pumps and controls,
and treatment chemicals.  Labor requirements for operation  and
maintenance are shown in Figure 8-4.  As can be seen  operating
labor is substantially higher for batch treatment  than  for  con-
tinuous operation.  Maintenance labor requirements for  continuous
treatment are fixed at 150 man-hours per year for  flow  rates below
87,055 1/hr and thereafter increase according to:

     Laborn = .000721 x (Flow-87,055) + 150
                             VIII-18

-------
Annual Labor Required (Manhours)
M (-i
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in3 104 105 1C
                Flow  Rate  (1/hr)
                  FIGURE 8-4
CHEMICAL OXIDATION OF CYANIDE ANNUAL  LABOR REQUIRED

-------
Maintenance labor requirements for batch treatment are  assumed
to be negligible.

Annual costs for treatment chemicals and electrical power  are
presented in Figure 8-5.  Chemical additions are determined
from cyanide, acidity, and flow rates of the raw waste  stream
according to:

     Ibs sodium hypochlorite. = 62.96 x Ibs CN
     Ibs sodium hydroxide = 0.8 x Ibs acidity

Chromium Reduction

This technology provides chemical reduction of hexavalent  chromium
under acid conditions to allow subsequent removal of  the triva-
lent form by precipitation as the hydroxide.  Treatment may  be
provided in either continuous or batch mode, and cost estimates
are developed for both.  Operating mode for system cost estimates
is selected on a least cost basis.

Investment Cost.  Cost estimates include all required equipment  for
performing this treatment technology including reagent  dosage,
reaction tanks, mixers and controls.  Different reagents are
provided for batch and continuous treatment resulting in dif-
ferent system design considerations as discussed below.

For both continuous and batch treatment, sulfuric acid  is  added
for pH control.  A 90 day supply is stored in the 25 percent
aqueous form in an above-ground, covered concrete tank, 0.305
m 1 ft) thick.

For continuous chromium reduction the single chromium reduction
tank is sized in an above-ground cylindrical concrete tank with
a 0.305 m (1 ft) wall thickness, a 45 minute retention  time, and
an excess capacity factor of 1.2.  Sulfur dioxide is  added to con-
vert the influent hexavalent chromium to the trivalent  form.

The control system for continuous chromium reduction  consists
of:

     1    immersion pH probe and transmitter
     1    immersion ORP probe and transmitter
     1    pH and ORP monitor
     2    slow process controllers
     1    sulfonator and associated pressure regulator
     1    sulfuric acid pump
     1    transfer pump for sulfur dioxide ejector
     2    maintenance kits for electrodes, and miscellaneous
          electrical equipment and piping
                             VIII-20

-------
  10
                                                                                  ^
01
M
nj
O
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q

<
  100
                                                        C\j
       xtt
                                                                 /
                                                                              ^
                                                                                        -.b?
                                                                                        ~v •
   10
     10
                       100
io3                10

  Flow  Rate (1/hr)


   FIGURE 8-5
                                                                                ID'
10<
                                CYANIDE OXIDATION CHEMICAL AND ENERGY COST

-------
For batch chromium reduction, the dual chromium  reduction  tanks are
sized as above-ground cylindrical concrete  tanks,  0.305  m  (1  ft)
thick, with a 4 hour retention time, and an  excess  capacity  factor
of 1.2.  Sodium bisulfite is added  to reduce  the  hexavalent  chro-
mium.

A completely manual system is provided for  batch  operation.   Sub-
sidiary equipment includes:

     1    sodium bisufite mixing and feed tank
     1    metal stand and agitator  collector
     1    sodium bisulfite mixer with disconnects
     1    sulfuric acid pump
     1    sulfuric acid mixer with  disconnects
     2    immersion pH probes
     1    pH monitor, and miscellaneous piping

Investment costs for batch and continuous treatment  systems  are pre-
sented in Figure 8-6.

Operation and Maintenance.  Costs for operating  and  maintaining
chromium reduction systems include  labor, chemical  addition,  and
energy requirements.  These factors are determined  as  follows:

     LABOR

The labor requirements are plotted  in Figure  8-7.   Maintenance
of the batch system is assumed negligible and so  it  is not shown.

     CHEMICAL ADDITION

For the continuous system, sulfur dioxide is  added  according  to
the following:

     (Ibs S02/day) = (58.4 x 10~6)  (flow to  unit-liters/day)  (Cr+5 rag/1)

In the batch mode, sodium bisulfite is added  in  place  of sulfur
dioxide according to the following:

     (Ibs NaHS03/day) = (75.9 x 10~6)  (flow  to  unit-liters/day)

      (Cr+6 mg/1)

     ENERGY

Two horsepower is required for chemical mixing.   The mixers  are
assumed to operate continuously over the operation  time  of the
treatment system.

Given the above requirements, operation and  maintenance  costs are
calculated based on the following:
                             VIII-22

-------
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  10
  10'
      1C
                          100
          io3                  io4
              Flow Rate (1/hr)


                  FIGURE 8-6

CHEMICAL REDUCTION OF  CHROMIUM INVESTMENT COST
10-
10'

-------
I   3
        10
                            100
  103                 104
      Flow Rate  (1/hr)


          FIGURE 8-7

CHROMIUM REDUCTION ANNUAL LABOR
10-

-------
          $6.71 per man + 15% indirect labor  charge
          $451/ton of sulfur dioxide
          $83.5/ton of sodium bisulfite
          $0.45/kilowatt hour of required electricity


Lime Precipitation and Sedimentation

This technology removes dissolved pollutants  by  the  formation
of precipitates by reaction with added lime and  subsequent  removal
of the precipitated solids by gravity settling in  a  clarifier.
Several distinct operating modes and construction  techniques
are costed to provide least cost treatment over  a  broad  range  of
flow rates.   Because of their interrelationships and integration
in common equipment in some installations, both  the  chemical
addition and solids removal equipment are addressed  in a single
subroutine.

Investment Cost - Investment costs are determined  for this
technology for continuous treatment systems using  either steel
or concrete tank construction, and for batch  treatment using
steel tanks only.  The least cost system is selected for each
application.  Continuous treatment systems include controls,
reagent feed equipment,  a mix tank for reagent feed  addition and
a clarification basin with associated sludge  rakes and pumps.  Batch
treatment includes only reaction-settling tanks  and  sludge  pumps.

Controls and reagent feed equipment:  Costs for  continuous
treatment systems include a fixed charge of $10817 covering an
immersion pH probe and transmitter, pH monitor,  controller, lime
slurry pump, 1 hp mixer, and transfer pump.   In  addition, an
agitated storage tank sufficient to hold one  day's operating
requirements of a 30% lime slurry is included.   Costs for this
tank are estimated based on the holding tank  costs discussed
later in this section and shown in Figure 8-10 .   Lime feed
to the slurry tank is assumed to be manual.   Hydrated lime  is
used and no equipment for lime slaking or handling is included
in these cost estimates.  At facilities with  high  lime
consumption mechanical lime feed may be used  resulting in higher
investment costs, but reduced manpower requirements  in comparison
to manual addition.

Mix Tank:  Continuous systems also include an agitated tank
providing 45 minutes retention for reagent addition  and  formation
of precipitates.  When the clarifier is concrete,  the mix tank is
also of concrete, below grade and adjacent to the  clarification
basin.   Costs shown in Figure 8-8 include both the mix tank
and clarifier as a single item.   For steel construction,  the
costs for the mix tank are based on holding tank costs shown in
Figure 8-10.

Clarifier:   The clarifier size is calculated  based on a  hydraulic
loading of  1356 1/m  and a retention time of  4 hours with a 20%
                             VIII-25

-------
10'
   1C
                       100
                                                 Flow Rate  (1/hr)
                                                     FIGURE  8-8
                                              CLARIFIER INVESTMENT COST
10-

-------
allowance for excess flow capacity.  Costs for clarifiers shown  in
Figure 8-8 include a mix tank as noted above, excavation  (if needed),
installation, and associated equipment including a mixer  and
clarifier rakes.   For steel construction, costs are estimated
for a cylindrical above ground clarifier with sludge collection
equipment.  The type of construction used is selected internally  in
the cost estimation program to provide least cost.

Sludge Pumps:  A cost of $3817 is included in the total capital
cost estimates regardless of whether steel or concrete construction
is used.  This cost covers the expense for two centrifugal
sludge pumps.

To calculate the total capital cost for continuous lime precipita-
tion and sedimentation in a clarifier, the costs estimated for the
controls and reagent feed system, mix tank,  clarifier and sludge
pump must be summed.

For batch treatment, dual above-ground cylindrical carbon steel
tanks sized for 8 hour retention and 20% excess capacity  are
used.  If the batch flow rate exceeds 19697 liters per hour, (5204
gph), then costs for fabrication are included.  To complete the
capital cost estimation for batch treatment, a fixed $3,817 cost  is
included for sludge pumps as discussed above.

Operation & Maintenance Costs - The operation and maintenance costs
for the Chemical Precipitation/Clarification routine include:

     1)   Cost of chemicals added (lime, alum, and polyelectrolyte)
     2)   Labor (operation and maintenance)
     3)   Energy

Each of these contributing factors is discussed below.

     CHEMICAL COST

     Lime, alum and polyelectrolyte are added for metals  and
     solids removal.  The amount of lime required is based on
     equivalent amounts of various pollutant parameters present
     in the stream entering the clarifier unit.  The methods
     used in determining the lime requirements are shown  in
     Table 8-5.  Alum and polyelectrolyte additions are
     calculated to provide a fixed concentration of 200 mg/1
     of alum and 1 mg/1 of polyelectrolyte.

     LABOR

     Figure 8-9 presents the manhour requirements for the
     continuous clarifier system.  For the batch system,
     maintenance labor is assumed negligible and operation
     labor is calculated from:

     (man-hours for operation) = 390 + (.975) x (Ibs. lime added
                                                 per day)

                             VIII-27

-------
      10
   l/l
   fn
   O

   I
   OJ
   H
t-H  BS
                                           Operation
£  1100
Maintenance
      10
         100
                              10'
          10*                   10-
              Flow  Rate  (1/hr)
10
10
                                                             FIGURE  8-9

                                                  LIME PRECIPITATION/CLARIFICATION
                                                        CONTINUOUS TREATMENT
                                                           LABOR -REQUIRED

-------
                         TABLE 8-5

            Lime Additions for Lime Precipitation

Stream Parameter                        Lime Addition
                                        kg/kg  (Ibs/lb)
                                             0.81
Aluminum                                     4.53
Antimony                                     1.75
Arsenic                                      2.84
Cadmium                                      2.73
Chromium                                     2.35
Cobalt                                       1.38
Copper                                       1.28
Iron (Dissolved)                             2.19
Lead                                         0.205
Magnesium                                    3.50
Manganese                                    1.48
Mercury                                      0.42
Nickel                                       1.45
Selenium                                     3.23
Silver                                       0.39
Zinc                                         1.25
                            VIII-29

-------
     ENERGY

     The energy costs are calculated from the clarifier  and
     sludge pump horsepower requirements.

     Continuous Mode

     The clarifier horsepower requirement is assumed  constant  over
     the hours of operation of the treatment system at a level of
     0.0000265 horsepower per 3.8 Iph  (1 gph) of  flow  influent to
     the clarifier.  The sludge pumps  are assumed operational  for
     5 minutes of each operational hour at a level of  0.00212
     horsepower per 3.8 Iph (1 gph) of sludge stream  flow.

     Batch Mode

     The clarifier horsepower requirement is assumed  to  occur  for
     7.5 minutes per operation hour at the following  levels:

          influent flow < 3944 Iph; 0.0048 hp/lph
          influent flow >_ 3944 Iph; 0.0096 hp/lph

     The power required for the sludge pumps in the batch system is
     the same as that required for the sludge pumps in the contin-
     uous system.

     Given the above requirements, operation and  maintenance
     costs are calculated based on the following:

               $6.71 per man-hour + 15% indirect  labor charge
               $44.61/metric ton of lime
               $48.55 metric ton of alum
               $1.95/kg of polyelectrolyte
               $0.045/kilowatt-hour of required electricity


Holding Tanks

Tanks serving a variety of purposes in wastewater treatment and
control systems are fundamentally similar in design,  construc-
tion and cost.  They may include equalization tanks,  solution
holding tanks, slurry or sludge holding tanks, mixing  tanks,
and settling tanks from which sludge is intermittently removed
either manually or by sludge pumps.  Tanks for all of  these pur-
poses are addressed in a single cost estimation subroutine with
additional costs for auxiliary equipment such as  sludge  pumps
added as appropriate.
                               VIII-30

-------
Investment Costs - Investment costs are estimated  for  either  steel
or concrete tanks.  Tank construction may be specified  as  input
data,  or determined on a least cost basis.  Retention  time  is  spe-
cified as input data and, together with stream  flow  rate,  determines
tank size.  Investment costs for steel and concrete  tanks  sized  for
0.5 days retention and 20% excess capacity are  shown as  functions
of stream flow rate in Figure 8-10. These costs  include  mixers,
pumps  and installation.

Operation and Maintenance Costs -  For all holding tanks except
sludge holding tanks,  operation and maintenance  costs  are  minimal
in comparison to other system O&M costs.  Therefore  only energy
costs  for pump and mixer operation are determined.   These  energy
costs  are presented in Figure 8-11.

For sludge holding tanks, additional operation  and maintenance
labor  requirements are reflected in increased O&M  costs.   The
required man-hours used in cost estimation are  presented in
Figure 8-12.  Labor costs are determined using  a labor  rate
of $6.71 per manhour plus 15% indirect labor charge.

Where  tanks are used for settling as in lime precipitation  and
clarification batch treatment, additional operation  and  maintenance
costs  are calculated as discussed specifically  for each  technology.
                             VIII-31

-------
n)
O
Q
i/l
O
C
(D
  100
     10
                          100
10
                                                    Flow  Rate  (1/hr)
                                                        FIGURE 8-10

                                                HOLDING TANKS INVESTMENT COST
10-
                                                                                       Retention Time  .5 day
lu'

-------
     10
   J-l
   ni
   O
   Q
I
OJ
OJ  4->
   O
   0)
   1	1
   UJ
ni

^103
    100
        100
                                                    H                   10
                                                      Flow Rate (1/hr)

                                                          FIGURE 8-11

                                                    HOLDING TANKS ENERGY COST
                                                                                                10
10

-------
 I
(jj
    100
                            10
                                                 100
                                                     Flow Rate  (1/hr)
                                                         FIGURE 8-12


                                                HOLDING TANK LABOR REQUIREMENTS

-------
Chemical  Emulsion Breaking - Skimming

This technology removes emulsified oil droplets by  chemically  de-
stabilizing them.  This allows the oil droplets to  agglomerate,
rise to the surface,  and be skimmed from the surface.  It  is assumed
that the  emulsion may be broken by chemical means alone, without
the addition of heat.  The oily waste are mixed with alum  and  a
chemical  emulsion breaker in a small tank and then  enter a large
tank.   The quiescent conditions in the large tank allow the oil
to rise and be skimmed.  Chemical emulsion breaking is most
appropriate where excessive free oils have already  been removed.

Investment Costs.  Investment costs include a small mixing tank, two
chemical  feed tanks,  a mixer, and a large tank equipped with an

oil skimmer and a sludge pump.  The small tank has  a retention time
of fifteen minutes,  the large tank has a retention  time of two and
one-half  hours, and  a 20% excess capacity is provided.  Figure 8-13
presents  the investment costs.

Operation and Maintenance Costs.  The operation and maintenance
costs include labor,  chemicals, and energy as detailed below.

     LABOR

     Figure 8-14 presents annual labor hours for chemical
     storage, handling, mixing, coagulation, and pumping
     of sludge.

     CHEMICALS

     150  mg/1 of chemical coagulant
      25  mg/1 of alum

     ENERGY

     The  minimum horsepower required is as follows:

     one  1/2 horsepower mixer operating 15 minutes  per hour
     of plant operation

     one  one horsepower sludge pump operating continuously

     one  one horsepower skimmer motor operating continuously

     Given the above, the following unit costs were used for de-
     termining operation and maintenance costs:

       $6.71 per man-hour + 15% indirect labor charge
       $.045/kilowatt-hour of required electricity
       $48.55/metric ton of alum
       $1.73/kg of  coagulant
                               VIH-35

-------
   10'
   10
O
Q
O
U

   10
   10'
      10
100
         10                   10*
             Flow Rate  (1/hr)


              FIGURE 8-13


CHEMICAL EMULSION BREAKING INVESTMENT COST
                                                                                         10-
10'

-------
     10
   o


   rt
<  3
M  cr
U)  O
     100
      10
         100
                             10-
10
10'
10
                                                       Flow Rate (1/hr)


                                                        FIGURE  8-14
                                           CHEMICAL EMULSION BREAKING LABOR REQUIRED

-------
Multi-Media Filtration

This technology provides removal of suspended  solids  by  filtration
through a bed of particles of several distinct  size ranges.   As  a
polishing treatment after chemical precipitation  and  clarification
processes, multi-media filtration provides  improved removal  of
precipitates and thereby improved removal of the  original  dissolved
pollutants.

Investment Cost.  The size of the multi-media  filtration unit is
based«on 20% excess flow capacity and a hydraulic  loading  of
.5 ft /gpm.  The investment cost, presented in  Figure  8-15 as a
function of flow rate, includes a backwash mechanism,  pumps,
controls, media and installation.

Operation and Maintenance.  The costs shown in  Figure  8-16 for
operation and maintenance includes contributions of materials,
electricity and labor.  These curves result from correlations
made with data obtained by a major manufacturer.   Energy costs
are estimated to be 3% of total O&M.

Ultrafiltration

Investment Cost.  The investment cost for ultrafiltration  is
calculated using a correlation developed from data supplied  by
a major manufacturer.  Figure 8-17 illustrates  the results for
this correlation.

Operation and Maintenance Costs

The unit is sized on the basis of a hydraulic  loading  of 1,430 I/
day/m  of surface area and an excess capacity  factor of 1.2.  The
operation and maintenance costs are made up of  contributions  from:

     1)   Labor
     2)   Membrane Replacement
     3)   Energy

Each of these factors are discussed below.

     LABOR

     Figure 8-18 shows curves of the man-hour requirements for both
     maintenance and operation.

     MEMBRANE REPLACEMENT

     One filter module is required per year for each 1892 liters
     (500 gallons)  per day of treated flow.
                               VIII-38

-------
     10'
     io
   in
   M
   ni
   o
   O
   u
v  §
ift  iri -L U
     icr
        1C
                              100
10'
                                                        Flow Rate  (1/hr)



                                                            FIGURE 8-15


                                                MULTIMEDIA FILTER INVESTMENT COSTS
10'

-------
     10'
  oo
  3
   o
   Q
   +J
   V)
   O
   u
   £
                                                                 <•«•"
                                                            A
I
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     10
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-------
     10'
  cr>
  t~-
Aug

|_r
o
ars
Do
nvestment Cost
^
o
I
>^
I-1
o
        10
                             100
10'
10-
10'
                                                       Flow  Rate  (1/hr)

                                                       FIGURE 8-17
                                             ULTRAFILTRATION INVESTMENT COST

-------
X
£ 10
o
,c

n)
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cr
a)
oi
  10-
nj



I
  100
     10
100
   io3                  io4

      Flow Rate  (1/hr)


       FIGURE 8-18


ULTRAFILTRATION LABOR REQUIRED
                                                                                        10-

-------
     ENERGY

     The power requirements based on 30.48 m of pumphead yield  a
     constant horsepower value of 0.006 horsepower per 3.74  1/hr
     (1 gph) flow to the ultrafiltration unit.

     Given the above requirements, opeation and maintenance  costs
     are calculated based on the following:

          $6.71 per man-hour + 15% indirect labor charge
          $260/ultrafiltration module
          $0.452/kilowatt-hour of required energy

CARBON ADSORPTION

Carbon Adsorption.  This technology removes organic pollutants  and
suspended solids by pore adsorption, surface reactions, and  physical
filtering by the carbon grains.  It typically follows other  types
of treatment as a means of polishing the effluent.  A variety of
carbon adsorption systems exist:  upflow, downflow, packed bed,
expanding bed, regenerative, and throwaway-  Regeneration of carbon
requires an expensive furnace and fuel for regeneration that are
not required for a throwaway system.  Large systems may find that
the high cost of replacement carbon make a regenerative system
economically attractive.

Capital Costs.  The capital costs presented in Figure 8-19 are  for
a packed-bed throwaway system as based on the EPA Technology Trans-
fer Process Design Manual for Carbon Adsorption.  They include  a
contactor system, a pump station, and initial carbon.  The design
assumes a contact time of 30 minutes, a hydraulic loading of
1.41 liters/minute/ft  (4 gpm/ft ,) and 20% excess capacity.

Operation and Maintenance Costs.  The chief operation and mainten-
ance costs are labor, replacement carbon, and electricity for the
pump station.  The labor hours required are computed using Figure
8-20,  which is taken from an EPA Technology Transfer.  The labor
unit cost used was $6.71/hr plus 15% indirect changes.  The  re-
placement carbon cost was calculated by assuming:

     1)   One pound of replacement carbon is required per
          pound of phenol (equivalents) removed.

     2)   The influent phenol concentration is 0.42 mg/1.

     3)   Activated carbon costs $$2.62/kg. ($1.19/lb).

Electrical costs were estimated using Figure 8-21, which uses a
unit cost of $.045/(kw-hr).
                             VIII-43

-------
   10
U1
H
ed
O
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t/1
0)
  ID'
      10
                           100
10J                   10'
    Flow Rate  (1/hr)
10-
                                                     FIGURE 8-19
                                     CARBON ADSORPTION INVESTMENT COST (THROWAWAY TYPE)

-------
   10
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I 100
rt
   10
      10
                          100
                                                   io3                   10

                                                     Flow  Rate  (1/hr)
10'
10
                                                   FIGURE 8-20
                                    CARBON ADSORPTION LABOR REQUIRED  (THROWAWAY TYPE)

-------
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                              CARBON ADSORPTION ELECTRICITY USAGE  (THROWAWAY TYPE)

-------
SLUDGE DRYING BEDS

Sludge Drying Beds.  This technology provides for the dewatering of
sludge by means of gravity drainage and natural evaporation.  Beds
of highly permeable gravel and sand underlain by drain pipes  allow
the water to drain easily from the sludge.  This is a non energy-
intensive alternative to sludge dewatering.

Investment Costs

The curve shown in Figure 8-22 illustrates the correlation used to
estimate the cost of sludge drying beds.  The investment cost is a
function of the settleable solids concentration in the stream in-
fluent to the sludge beds, however, as shown by these curves, the
effect of solids concentration is very small in comparison to the
dependence on flow rate.

Operation and Maintenance

Operation and maintenance costs for sludge drying beds include labor
and material.  Figure 8-23 shows operation labor requirements and
Figure 8-24 shows maintenance labor requirements.

The cost of material required to maintain and operate the sludge beds
is shown in Figure 8-25.

Countercurrent Rinse - The costs of countercurrent rinsing without
using the first stage for evaporative loss recovery are presented
in Table 8-6 as a function of the number of rinse tanks utilized.
Costing assumptions are:

     A.   Unit cost is based on open top stainless steel
          tanks with a depth of 1.22 meters (4 feet), length
          of 1.22 meters (4 feet), and width of 0.91 meters
          (3 feet).  Investment cost includes all water and air
          piping, a blower on each rinse tank for agitation,
          and programmed hoist line coversions.

     B.   Operation and maintainance costs include a cost for
          electricity for the blowers based on a capacity of
          1,219 liters/min./sq. meter of tank surface area
          (4 cfm/sq. ft.) at a discharge pressure of 1,538
          kg/sq. meter/meter of tank depth (1 psi/18 in.).
          Fan efficiency is assumed to be 60 percent.  A
          water charge based on a rinse ratio of 8,180 is
          also included.  Rinse maintenance charges are assumed
          to be negligible when compared to normal plating line
          matintenance and are ignored.
                             VIII-47

-------
10
Investment Cost (Dollars - Aug,79)
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               FIGURE 8-23
SLUDGE DRYING BED LABOR REQUIRED  FOR OPERATION

-------
ID-
             Assumptions   1)  16 Hours of Operation/Day
                          2)  260 Days of Operation/Year
O
O
   10
100
io
3

 Plow Rate (1/hr)


  FIGURE 8-24
                                                                                         10-
10'
                                  SLUDGE DRYING BED  LABOR REQUIRED FOR MAINTENANCE

-------
     10
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     10-
   O
   Q
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   JS 100

      10
Assumptions   1)  16 Hours of Operation/Day
                260 Days of Operation/Year
                                                                          ^
                                                   10J                   10

                                                     Flow Rate  (1/hr)
                                                      FIGURE 8-25
                                           SLUDGE DRYING BEDS ANNUAL MATERIAL COST

-------
                         TABLE 8-6

       COUNTERCURRENT RINSE (FOR OTHER THAN RECOVERY

               OF EVAPOPRATIVE PLATING LOSS)



Number of Rinse Tanks         345

Investment                 10,794    13,88     16,978

Annual Costs:

     Capital Cost             909     1,170     1,430

     Depreciation           2,158     2,777     3,396

     Operation & Maintenance
     Costs (Excluding Energy
     & Power Costs)            27        12         8

     Energy & Power Costs     511       682       851

      Total Annual Cost    $3,605    $4,641    $5,685
                              VIII-52

-------
Countercurrent Rinse Used for Recovery of Evaporative Plating
Loss - The costs of countercurrent rinsing with a rinse flow rate
sufficient to replace plating tank evaporative losses are presented
in Table 8-7.  The results are tabulated for various evaporative
rates which are equal to the rinse water flow rates.  Costing assump-
tions are:

     A.   Unit cost is based on a sufficient number of rinse
          stages to replace the evaporative loss from a
          plating bath at approximately 43 degrees C while
          also maintaining a rinse ratio of 8,180.

     B.   Investment costs include open top stainless steel
          tanks with a depth of 0.91 meters (3 feet), length
          of 1.22 meters (4 feet), and width of 1.22 meters
          (4 feet).  All water and air piping, a blower on each
          rinse tank for agitation, a liquid level controller,
          solenoid, and pump are also included in the invest-
          ment cost.  Operation is assumed to be programmed
          hoist and line conversion costs are included.

     C.   Operation and maintenance costs include a cost for
          electricity for the blowers based on a capacity of
          1,219 liters/min/sq. meter of tank surface area (4
          cfm/sq. ft.) at a discharge pressure of 1,538
          kg/sq. meter/meter of tank depth (1 psi/18 in.).  A
          fan efficiency of 60 percent is assumed.  A water
          charge is also included.  Rinse maintenance charges
          are assumed to be neglibible when compared to
          normal plating line maintenance and are ignored.

Submerged Tube Evaporation - Submerged tube evaporation invest-
ment costs are shown for double effect units in Figure 8-26.
Costing assumptions are:

     A.   Unit size, power requirements, and operational
          expenses (less energy and power) are based on data
          supplied by the manufacturer for standard size
          units.

     B.   Investment cost includes the basic evaporator and
          bath purification device.

     C.   Evaporative heat of 583 cal/gram of wastewater is
          required for single effect units, and 292 cal/gram
          is required for double effect units.  The heating
          value of fuel is assumed to be 10,140 cal/gram
          (Lower Heating Value (LHV), API of 30) with a heat
          recovery of 85 percent.
                             VIII-53

-------
                         TABLE  8-7

         COUNTERCURRENT RINSE USED  FOR  RECOVERY  OF
                  EVAPORATIVE PLATING LOSS
Evaporative Rate
(Liters/Hr)                      15.3            24.0            50.8

Investment                    $15,430         $12,736         $10,042

Annual Costs:

  Capital Costs                 1,301           1,074             847
  Depreciation                  3,086           2,547           2,008

  Operation & iMaintenance
  Costs (Excluding Energy
  & Power Costs)                 4.54             6.8            16.0

  Energy & Power Costs            714             572             428

    Total Annual Cost         $ 5,105         $  4,200         $  3,300

Note:  Savings due to recovery of plating solution  are  not
       presented in this table.
                             VIII-54

-------
10





Investment Cost (Dollars - Aug. 79)
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io3 io4 io5 i
                                                   Flow  Rate  (1/hr)
                                                   FIGURE 8-26
                               SUBMERGED TUBE  (DOUBLE EFFECT)  EVAPORATOR INVESTMENT COST

-------
     D.,    A cooling water charge is not  included  in  the
          operation and maintenance cost.  A  cooling water
          circuit is assumed to already  exist  for  the  plant.

     E,.    The condensate is assumed to be pure with  the  per-
          centage of condensate and concentrate flow split
          96.33% evaporate and 3.67% concentrate  is  left.

Contract Removal

Sludge,,  waste oils, and in some cases concentrated waste .solutions
frequently result from wastewater treatment processes.   These  may
be disposed of on-site by incineration,  landfill  or  reclamation,
but are most often removed on a contract basis for off-site dis-
posal.  System cost estimates presented  in this report are based
on contract removal of sludges and waste oils.  In addition,
where only small volumes of concentrated wastewater  are  produced,
contract-removal of off-site treatment may represent the most  cost-
effective approach to water pollution abatement.   Estimates of so-
lution contract haul costs are also provided  by this subroutine
any may be selected in place of on-site  treatment  on a least-cost
basis,

Investment Costs.  The investment for contract removal is zero.

Operating Costs.  Annual costs are estimated  for  contract removal
of total waste streams or sludge and oil streams  as  specified  in
input data.  Sludge and oil removal costs are  further  divided  into
wet and dry haulage depending upon whether or  not  upstream sludge
dewatering is provided.  The use of wet  haulage or sludge de-
watering and dry haulage is based on least cost as determined  by
annualized system costs over a five year period.  Wet  haulage  costs
are always used in batch treatment systems and when  the  volume of
the sludge stream is less than 378 liters per  day  (100 gpd).

Both wet sludge haulage and total waste  haulage differ in cost de-
pending on the chemical composition of the waste  removed.  Wastes
are classified as cyanide bearing, hexavalent  chromium bearing, or
oily and assigned different haulage costs as  shown below.

     Wasjte Composition             Haulage Cost

     M).05 mg/1 CN~                $.16/liter  ($.60/gallon)
     X).l mg/1 Cr °                $.18/liter  ($.56/gallon)
     Oil & grease XTSS             $.08/liter  ($.08/gallon)
     All others                    $.06/liter  ($.24/gallon)

Dry sludge haul costs are estimated at $0.08/liter gallon and
40% dry solids in the sludge.

TREATMENT SYSTEM COST ESTIMATES

This section presents estimates of the total  cost  of wastewater
treatment and control systems for metal  finishing  process waste-
water incorporating the treatment and control  components discussed


                              VIII-56

-------
above.   Flows in the Metal Finishing Category vary  from  approxi-
mately  378 to 3,785,000 liters/day  (100 gpd to 1,000,000 gpd).
This wide variation in flow rate necessitates the presentation
of treatment system total annual cost curves for each option.
Total annual costs have been plotted against flow in units  enabling
the determination of cost for any flow rate.  Implicit in these
curves  is the fact that from zero to 1892 liters/day  (500 gpd)  it
is most economical for a plant to have all wastewater hauled  to
a licensed treatment facility.  From this flow rate to 946,250
liters/day (250,000 gpd) an on-site batch treatment system  is
most economical and above this flow, an on-site continous system
is cost-effective.  All available flow data from industry data
collection portfolios were used in  defining the raw waste flows.
Raw waste characteristics were determined based on  sampling data
as discussed in Section V.

The system costs presented include  component costs  as discussed
above and subsidiary costs including engineering, line segrega-
tion, administration, and interest  expenses during  construction.
In developing cost estimates for these option systems, it is  as-
sumed that none of the specified treatment and control measures
are in place so that the presented  costs represent  total costs
for the systems.

System Cost Estimates (Option 1)

This section presents the system cost estimates for the  Option  1
end-of-pipe treatment systems.  The representative  flow  rates used
in this option system cost estimates were determined as  being
typical based upon actually sampled flows and flow  information
received in the data collection portfolios.  The complete system
block diagram is shown in Figure 8-27.

At different industry plants, different subcategories of waste  may
or may not be present.  To present  costs applicable to a variety
of plants, five cases corresponding to five combinations of sub-
category waste flows are modeled for Options 1, 2,  and 3.   Table
8-8 presents these cases and the percentage of the  total plant  ef-
fluent that is assumed to come from each subcategory.  The  flow
percentages are based on the average subcategory flows in collected
data.  Where there is no flow in a  subcategory, unnecessary down-
stream treatment components are not costed.

The costing assumptions for each component of the Option 1  system
were discussed above under Technology Costs and Assumptions.  In
addition to these components, contractor sludge removal  was in-
cluded  in all cost estimates.

Table 8-9 presents costs for various treatment system  influent  flow
rates.   The basic cost elements used in preparing these  tables  are
the same as those presented for the individual technologies:   invest-
ment, annual capital costs, annual  depreciation, annual  operations
and maintenance cost (less energy cost), energy cost,  and  total annual
cost.  These elements were discussed in detail earlier  in  this  section,
                                VIII-57

-------
I
(ji
oo
                Oily Raw Waste
              P
Emulsion

Breaking
          Skimmed Oil
                     Raw Waste      Raw Waste     Raw Waste
  Cyanide

Oxidation
 Chromium

Reduction
                                          Common

                                          Metals
                                                       Clarifier
                                                                      Sludge         Sludge
                                                       Treated
                                                       Effluent
                                                           Sludge

                                                        Drying Beds
                                                         Raw Waste
                                                              Complexed

                                                                Metals
                                                                              Clarifier
                                                          Treated
                                                         Effluent
                                                                           Contractor

                                                                             Removal
                                                          FIGURE 8-27


                                                        OPTION  1  SYSTEM

-------
                         TABLE 8-8




          FLOW SPLIT CASES FOR OPTIONS 1, 2, AND 3






Case            Subcategory Flows (% of total plant flow)
1




2




3




4




5
Oily


3i.5
30
30
Cyanide
7
6
4.5

4
Chromium
13
12.5
9

9
Common
Metals
80
75. 5
55
70
52. 5
Complex
Metals

6


4.5
                               VIII-59

-------
                                                 TABLE  8-9


                                               Option 1 Costs
I
o>
o
Case
Number
i
2
3
4
5
1
2
3 	
4
5
1
2
3
4
5 	
1
2
3
4 	
5
1
2
3 	
4
5
1
2
3
4
5
1 	 	
2
3
4
5
1
2
3
f.
5


CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
	 CONTNUOS
CCNTNUOS
CONTNUOS
CCNTNUOS
BATCH
BATCH
BATCH
BATCH
BATCH .
BATCH
BATCH
BATCH
	 BATCH .. . .
BATCH
BATCH
B4TCH
	 BATCH 	
BATCH
BATCH
CONTNUOS
	 CONTNUDS -
CONTNUOS
CONTNUOS
CONTNUOS
	 	 CONTNUOS...
CONTNUOS
CCNTN'JOS
CONTNUOS
CONTNUOS .
CCNTNUOS
CONTNUOS
CCNTNUOS
CONTNUQS
CONTNUOS

<^
112.
112.
96 .
60.
112.
9933.
9974.
9974.
9980.
9934.
9933.
9974.
9974.
9930.
	 9984.
49990.
49920.
49940.
	 50000.
49940.
499900.
499500.
..499500....
500000.
499500.
49990.
... 49920...
49940.
50000.
49940.
....250000. .
250200.
249400.
250000.
..249700.
499900.
499500.
499500.
...500000...
499500.
Oj"
^
26.49
26.49
22.71
13.92
26.49
2362.79
2359.47
2359.47
2360.89
2361.84
2362.79
2359.47
2359.47
2360.69
. ... 2361.84
11625.75
11609.20
11813.93
...11828.12
11813.93
118257.50
118162.87
..113162.87 .
118281.19
118162.87
11825.75
.... 11509.20
11813.93
11623.12
11813.93
. .59140.61 -
59137.92
53998.67
59140.62
... 59069.62.
113257.50
113162.87
113162.87
.118281.19 .
118162.37
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.125
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.437
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12033.340
12113.203
11367.316
6°CS.895
12456.844
826142.125
811133.500
810537.000
665164.187
804602.750
42587.512
47648.867
62241.051
54785.477
67019.937
60059.437
66296.500
112209.125
93153.375
117959.625
337377.687
390^30.125
505446.125
354466.437
507930.437
Q5S12.812
109291.687
129305.812
93479.375
142238.125
212633.375
230724.312
2°2323.375
211711.750
303688.000
341830.637
351332.937
471520.500
3 " ^ T 0 C. 500
479245.750

-------
 For the cost computations, a least cost  treatment  system  selection
 was performed.  This procedure calculated the costs for a  batch
 treatment system, a continuous treatment  system, and haulaway  of
 the complete wastewater flow over a 5 year comparison period.
 Figures 8-28 through 8-32 show the total  annul costs for each  case
 shown in Table 8-8.

 The various investment costs assume that  the treatment  system  must
 be specially constructed and include all  subsidiary costs  discussed
 under the Cost Breakdown Factors segment  of this section:  It  is
 also assumed all plants operate 16 hours  a day, 5 days per week, for
 52 weeks per year (260 total days).

 System Cost Estimates (Option 2)

 System cost estimates of the effects of adding a multimedia filter
 to the previously discussed  end-of-pipe systems were developed
 to provide Option 2  Treatment Cost Estimates.  A schematic of  the
 System is shown in Figure 8-33.  The cases used are the same as
 those for Option 1 and are shown  in Table 8-8.  The costing assump-
 tions for the multimedia filter were discussed above under the
 technology costs and assumptions subsection.

 Several flow rates were used for  each case to effectively model a
 wide spectrum of plant sites.  Figures 8-34 through 8-38 present
 the total annual costs for each case in Option 2.

 Table 8-10 presents  Option 2 treatment costs for construction of
 the entire end-of-pipe system.  These costs would be representative
 of  expenditures to be  expected  to  attain Option 2 for  a plant with
 no  treatment  in place.

 System Cost  Estimates  (Option 3)

 The Option 3  system  takes the Option  2  system and makes two signi-
 ficant  changes.   First,  a carbon adsorption  bed is added after
 the ultrafiltration  to  further  reduce  the discharge of  oily wastes
 and priority  organics.   The  second  change requires the  closed loop
 operation  (zero discharge) of any  processes  using either cadmium
 or  lead.   For  costing  purposes, an  evaporative  system  has been
 used  with  the  condensate  reused for rinsing  and the concentrate
 hauled  for disposal.  This may  also be  accomplished by  other  means
 selected by the  individual plants.  Closed loop precipitation
 with reuse of the  treated water and licensed  hauling of  the sludge
 or  ion exchange, reuse of the water and  treatment and hauling of
 the regenerate  solution are two possible options.   The  schematic
for the complete Option 3 is shown in Figure 8-39 and the total
annual cost curves for  each case are shown in Figure 8-40 through
8-44.  Table  8-11 presents a  summary of the Option  3 costs.
                              VIII-61

-------
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                                                     FIGURE 8-28


                                           TOTAL  ANNUAL COST vs FLOW  RATE

                                       FOR OPTION 1  TREATMENT SYSTEM,  CASE 1
                                                                                         Haul
                                                                                         Batch
                                                                                         Continuous

-------
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-------






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-------
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            Flow Rate (Ipd)
             FIGURE 8-32

    TOTAL ANNUAL COST vs FLOW RATE
FOR OPTION 1 TREATMENT SYSTEM, CASE S
Haul
Batch
Continuous

-------
              Oily Raw Waste
Raw Waste      Raw Waste     Raw Waste
  Skimmed Oil
M
M
I
                  Emulsion
                  Breaking
 Cyanide
Oxidation
              Ultrafi1trat ion
                                  Oil
 Chromium
Reduction
                                                           Common
                                                           Metals
                                                     Clarifier
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                                                     Multimedia
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        Sludge
     Drying Beds
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              Metals
                                                        Clarifier
Sludge
Multimedia
  Filter
                                   Contractor
                                     Removal
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                            Effluent
                                                            FIGURE 8-33
                                                          OPTION 2 SYSTEM

-------
      10'
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      10
        100
                             io
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10
10
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                                                    Flow Rate  (Ipd)
                                                     FIGURE  8-34

                                           TOTAL ANNUAL COST vs FLOW RATE
                                       FOR OPTION 2 TREATMENT SYSTEM, CASE 1
                                             Haul
                                             Batch
                                             Continuous

-------
a\
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-------
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                                           TOTAL  ANNUAL COST VS FLOW RATE
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-------
  10'
                                                Vf
en
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a

0
EH
  10
                                                                                 10
              10
                                              Flow Rate (Ipd)
                                               FIGURE 8-38

                                      TOTAL ANNUAL COST vs FLOW RATE
                                  FOR OPTION 2 TREATMENT SYSTEM, CASE  5
Haul
Batch
Continuous

-------
I
-o
                                                TABLE 8-10


                                              Option 2 Costs
                                                                                     &
Case
Number
i
2
3
4
5
1 	 „ 	
2
3
4
5.. 	
1.
c
3
4 	
5
1
2
3
4
5
1
2
3
4
5
1 	
2
3
4
5
1
2
3
4
5
1
2
3 	
4
5


CONTNUOS
	 	 CONTKUOS .
CONTNUOS
CONTNUOS
CONTNUOS
	 	 CQNTKUOS
CONTKUOS
CONTNUOS
CONTNUOS
	 	 „ 	 .... CCNTNUOS .
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CCNTNUOS
	 CONTKUOS '"
CONTNUOS
CONTNUOS
	 CONTNUOS .
CONTNUOS
CCNTNUOS
CONTNUOS
	 CCNTNUOS
CONTNUOS
CONTNUOS

£?
112.
	 112. .
96.
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112.
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499900.
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499500.
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49940.
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2361.84
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11828.12
11813.93
113257.50
118162.87
118162.87
113261.19
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11825.75
11809.20
11813.93
11828.12
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	 59140. 6f
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-------
             Oily Raw Waste
Raw Waste      Raw Waste     Raw Waste
Skimmed Oils
                Emulsion
                Breaking
 Cyanide
Oxidation
            Ultrafiltration
                                Oil
                 Carbon
               Adsorption
                                                                      I
 Chromium
Reduction
                                                         Common
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                                                   Clarifier
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                                                  Multimedia
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                                                              Complexed
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                                                        Clarifier
Sludge
Multimedia
  Filter
                                                   Treated
                                                   Effluent
                                   Contractor
                                     Removal
                            Treated
                            Effluent
                                                     FIGURE  8-39

                                                   OPTION  3  SYSTEM

-------





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FOR OPTION 3 TREATMENT  SYSTEM,  CASE 1
Haul
Batch
Continuous

-------






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    TOTAL ANNUAL COST vs FLOW RATE
FOR OPTION 3 TREATMENT SYSTEM, CASE 2
Haul
Batch
Continuous

-------





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             FIGURE 8-42

    TOTAL ANNUAL COST VS FLOW RATE
FOR OPTION 3 TREATMENT SYSTEM, CASE  3
Haul
Batch
Continuous

-------
00




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    TOTAL ANNUAL COST vs FLOW RATE
FOR OPTION 3 TREATMENT SYSTEM, CASE  5
            Haul
            Batch
——«•——• Continuous

-------
I
oo
o
                                                 TABLE  8-11


                                               Option 3 Costs
                                                                                            ~.
Case
Number
i
2
3
^
5
1
2
3 	
4
5
1
i>
3
4
5
1
2
3
4
5
1
2
3
^
5
1
2
3

5
1
2
3
4
5
1
2
3
4
5 	


CONTNUOS
CONTNUOS
CONTNUOS
	 CONTNUOS
CONTNUOS
CONTNUOS
CCNTNUOS
	 „ 	 CONTNUOS
CONTNUOS
CONTNUOS
BATCH
	 _ 	 ,,. ..BATCH 	
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
BATCH
CONTNUOS
CONTNUOS
CQNTNUQS
CONTNUOS
CONTNUOS
CONTNUOS
CQNTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS
CONTNUOS

<£yd
112.
112.
96.
80.
112.
9988.
9974.
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9980.
9984.
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9930.
9984.
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49920.
49940.
50000.
49940.
499900.
499500.
499500.
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499500.
49990.
49920.
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49940.
250000.
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499500.
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22.71
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2361.84
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2359.47
2360.89
2361.84
	 11825.75.
11809.20
11813.93
11828.12
11813.93
118257.50
118162.67
118162.87
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118162.87
11825.75
11609.20
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59140.61
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-------
 Use of ccrglE:  Estimation  Results

 Cost  estimates  presented in the tables and figures in this section are
 representative  of  costs typically incurred in implementing treatment
 and control  equivalent  to the specified options.  They will not, in
 general,  correspond  precisely to cost experience at any individual
 plant.  Specific  plant  conditions such as age, location, plant layout,
 or present production and treatment practices may yield costs which
 are either higher  or lower than the presented costs.  Because the costs
 shown are total system  costs and do not assume any treatment in place,
 it is probable  that  most plants will require smaller expenditures to
 reach the specified  levels of control from their present status.

 The actual costs  of  installing and  operating a system at a particular
 plant may be  substantially lower than the tabulated values.  Reductions
 in investment and  operating costs are possible in several areas.  De-
 sign  and  installation costs may be  reduced by using plant workers.
 Equipment costs may  be  reduced by using or modifying existing equip-
 ment  instead of purchasing all new  equipment.  Application of an excess
 capacity  factor, which  increases the size of  most equipment foundation
 costs could be  reduced  if  an  existing concrete pad or floor can  be uti-
 lized.  Equipment  size  requirements may be reduced by the use of  treat-
 ment  (for example, shorter  retention time)  of particular waste streams.
 Substantial reduction in  both investment  and  operating cost may  be
 achieved  if a plant  reduces its water use rate below that assumed in
 costing.

 IN-PROCESS FLOW REDUCTIONS

 The use of in-process techniques to achieve reductions in waste  flows
 can result in significantly reduced operating and maintenance costs.
 Although  an additional  initial  investment will be required  for a
 countercurrent rinse or other flow  reducing equipment, downstream
 treatment components may be  sized for  smaller flows.   This  reduces  the
 initial  investment for downstream treatment components.

 ENERGY AND NON-WATER QUALITY ASPECTS

 Energy and non-water  quality apsects of the wastewater treatment  tech-
 nologies  described in Section VII are  summarized  in Tables  8-12 and 8-13.
 Energy requirements are  listed, the  impact on environmental air and  noise
 pollution  is  noted, and  solid waste generation characteristics are  sum-
 marized.   The treatment  processes are divided  into two groups, waste-
 water  treatment  processes on Table 8-12 and sludge and solids handling
 processes  on  Table 8-13.

 Energy Aspects

 Energy aspects of  the wastewater treatment processes  are  important
 because of the impact of energy use on our natural resources  and  on
 the economy.  Electrical power and fuel requirements  (coal, oil,  or gas)
are listed in units of kilowatt hours per ton of dry  solids for sludge
and solids handling.   Specific energy uses are noted  in the "Remarks"
column.
                              VIli-81

-------
                                                    TABLE 8-12

                                NON-WATER QUALTY ASPECTS OF WASTEWATER TREATMENT
 PROCESS
     ENERGY REQUIREMENTS
                                NON-WATER QUALITY IMPACT
 Chemical Reduction
 Skimming
 Clarification
 Chemical  Precipitation

 Sedimentation


 Reverse Osmosis

 Ultraf iltrat ion

 Electrochemical
 Chromium  Reduction

 Chemical  oxidation
 by Chloride

 Chemical  Emulsion
 Breaking

 Deep Bed  Filtration


 Carbon Adsorption
 Throwaway


Evaporation


Countercurrent Rinse
Power
kwh
00 liters
1.0
0.01-.3
0.1-3.2
1.02
0.1-3.2
3.0
1.25-3.0
0.2-0.8
4.4-9.6
.1-3.2
.02-1.0
Fuel Energy
kwh use
1000 liters
— ' — Mixing
	 Skimmer Drive
	 Sludge Collec-
tor Drive
	 Flocculation
Paddles
	 Sludge Collector
Drive
	 High Pressure
Pump
High Pressure
Pump
— Reactifier, Pump
	 Mixing
	 Mixer, Skimmer,
Sludqe Pump
	 ue.;u, jJackwash
Air
Pollution
Impact
None
None
None
None
None
None
None
None
None
None
None
Noise
Pollution
Impact
None
None
None
None
None
Not
Objectionable
Not
Objectionable
None
None
Hot
Objectionable
None
Solid
Waste
None
Concentrated
Concentrated
Concentrated
Concentrated
Dilute
Concentrate
Dilute
Concentrate
Concentrate
None
Concentrated
Concentrated
Solid Waste
Concentration
* Dry Solids
5-50 (oil)
1-10
3-10
1-3
1-40
1-40
1-3
	
1-3 (TSS)
Variable
.'U8
Pumps

Head, Backwash
Pumps
	       2,500,000    Evaporation
                       Negligible
                                         None        None

                                         Depends On
                   Volatiles
                   Present

                   None
                                                     None
Concentrated


Concentrated


None
                                                                                       Variable
                                                                                        50-100

-------
                                                    TABLE 8-13

                           NON-WATER QUALITY ASPECTS  OF  SLUDGE AND SOLIDS HANDLING
PROCESS
                           ENERGY REQUIREMENTS
                                                                          NON-WATER QUALITY IMPACT




<2
M
M
l-l
1
00
OJ






Sludge
Thickening

Pressure
Filtration
Vacuum
Filter
Centrifugation

Landfill

Lagooning
Sand Bed Drying
rower
kwh
ton dry solids
29-930

21

16.7-
66 .*8
0.2-
98.5

	

- —
	
Fuel Energy
kwh Use
ton dry solids
— Skimmer,
Sludge Rake
Drive

	 High Pressure
Pumps

	 Vacuum Pump,
Rotation
	 Rotation

20-980 Haul, Land-
fill 1-10
Mile Trip
36 Removal
Equipment
25 Removal
Equipment
Air
Pollution
Impact
None


None

None
None

None

None
None
Noise
Pollution
Impact
None


None

Not
Objectionable
Not
Objectionable
None

None
None
Solid
Waste
Concentrated


Dewatered

Dewatered
Dewatered

Dewatered

Dewatered
Dewatered
Solid Wa
Concentr
* Ttrv Sf
o LJLy tj*—
4-27


25-50

12-40
15-50

N/A

3-5
15-40
                                                                                                                        Solid Waste
                                                                                                                        Disposal
                                                                                                                        Technique

                                                                                                                       Dewater & Landfill
                                                                                                                       or Incinerate
                                                                                                                     Landfill or Incinerate


                                                                                                                     Landfill or Incinerate


                                                                                                                     Landfill or Incinerate


                                                                                                                         N/A



                                                                                                                       Dewater & Landfill

                                                                                                                       Landfill

-------
Energy requirements are generally low, although  evaporation  can be
an exception if no waste heat is available at  the  plant.   Thus,
if evaporation is used to avoid discharge of pollutants,  the in-
fluent water rate should be minimized.  For example,  an  upstream
reverse osmosis or ultrafiltration unit can drastically  reduce
the flow rate of wastewater to an evaporation  device.

Non-Water Quality Aspects

It is important to consider the impact of each treatment  process
on air, noise, and radiation pollution of the  environment to pre-
clude the development of a more adverse environmental  impact.

In general, none of the liquid handling processes  causes  air pol-
lution.  Alkaline chlorination for cyanide destruction and chromium
reduction using sulfur dioxide also have potential  atmospheric
emissions.  With proper design and operation,  however, air pollu-
tion impacts are eliminated.  Incineration of  sludges or  solids
can cause significant air pollution which must be  controlled by
suitable bag houses, scrubbers, or stack gas precipitators as well
as proper incinerator operation and maintenance.   Care must  be  taken
to insure that solids collected in air pollution control  do  not
become a water pollution threat.  None of the wastewater  treatment
processes causes objectionable noise and none of the  treatment
processes has any potential for radioactive radiation hazards.

The solids waste impact of each sludge dewatering  process is
indicated in two columns on Table 8-13 .  The  first column shows
whether effluent solids are to be expected and,  if  so, the solids
content in qualitiative terms.  The second column  lists typical
values of percent solids of sludge or residue.   The third column
indicates the ususal method of solids disposal associated with
the process.

The processes for treating the wastewaters from  this  category pro-
duce considerable volumes of sludges.  In order  to  ensure long-term
protection of the environment from harmful sludge  constituents,
special consideration of disposal sites should be  made by RDRA  and
municipal authorities where applicable.  All landfill sites  should
be selected to prevent horizontal and vertical migration  of  these
contaminants to ground or surface waters.  In cases where geologi-
cal conditions may not be expected to prevent  this, adequate me-
chanical precautions (e.g., impervious liners) should be  used for
long-term protection of the environment.  A program of routine
periodic sampling and analysis of leachates is advisable.  Where
appropriate, the location of solid hazardous materials disposal
sites should be permanently recorded in the appropriate office  of
legal jurisdiction.
                              VIII-84

-------
                     SECTION IX
   BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
       AVAILABLE, GUIDELINES AND LIMITATIONS
These limitations will be developed at a later date,
                        IX-1

-------
                   SECTION X
     BEST AVAILABLE TECHNOLOGY ECOMONICALLY
     ACHIEVABLE, GUIDELINES AND LIMITATIONS
These limitations will be developed at a  later date.
                       X-l

-------
                     SECTION XI
          NEW SOURCE PERFORMANCE STANDARDS
These limitations will be developed at a later date.
                        XI-1

-------
                     SECTION XII
                    PRETREATMENT
These limitations will be developed at a later date,
                        XII-1

-------
                          SECTION XIII

                        ACKNOWLEDGEMENTS


The Environmental Protection Agency was aided in the preparation
of this Development Document by Hamilton Standard, Division of
United Technologies Corporation.  Hamilton Standard's effort was
managed by Mr. Daniel J. Lizdas, Mr. Walter M. Drake and Mr.
Robert W. Blaser.  Mr. Jeffrey M. Wehner and Mr. Kenneth J.
Dresser directed the engineering activities and field operations
were under the direction of Mr. Richard Kearns.

Significant contributions were made by Eric Auerbach, Steven
Bauks, Lewis Hinman, Robert Lewis, Joel Parker, James Pietrzak,
Donald Smith, and Stephen Wendt.  Data and information acquisition,
analysis, and processing were performed by Clark Anderson,
Michael Derewianka, Remy Halm, Robert Patulak, and John Vounatso.

Mr. Devereaux Barnes, Mr. J. Bill Hanson, and Mr. Richard Kinch
of the EPA's Effluent Guidelines Division served as Project
Officers during the preparation of limitations and the prepara-
tion of this document.  Mr. Robert Schaffer, Director, Effluent
Guidelines Division, and Mr. G. Edward Stigall, Chief, Inorganics
Chemicals and Services Branch, offered guidance and suggestions
during this project.

Acknowledgement and appreciation is also given to Ms. Kaye Starr
and Ms. Carol Swann of the word processing staff, Mrs. Lynne
McDonnell, Ms. Lori Kucharzyk, and Ms. Kathy Maceyka of Hamilton
Standard, and those of the secretarial and administrative staff
of the Effluent Guidelines Division who worked so diligently to
prepare, edit, publish and distribute the manuscript.

Finally, appreciation is also extended to those metal finishing
industry associations and plants that participated in and con-
tributed data for the formulation of this document.
                          XIII-1

-------
SECTION XIV




 REFERENCES
       XIV-1

-------
OIL, SOLVENT, AND CHEMICAL RECOVERY


"A Low-Cost Answer to Oil Recycling?"
Factory Management, January 1977, pp. 32-33.

Bech, B.C., Giannini, A.P., and Ramirez, E.R.,
"Electrocoagulation Clarifies Food Wastewater", Reprinted
from Food Technology, Vol. 28, No. 2, 1974, pp. 18-22.

Belinke, Robert J., "Central Filtration for Coolants",
American Machinists, December 1976, pp. 86-88.

Bolster, Maurice, "How to Maintain Emulsion Coolant Systems",
Modern Machine Shop, March 1977, pp. 112-115.

Bowes, H. David, "In-House Solvent Reclamation Eliminates
Quality Problems at Low Cost", Plastics Design & Processing,
May 1978, pp. 20-32.

Chonisby, J. and Kuhn, D., "Practical Oil Reclamation,
Purification", Hydraulics & Pneumatics, April 1976, pp. 71-73.

Chua, John P-, "Coolant Filtration Systems",
Plant Engineering, December 23, 1976, pp. 46-51.

"Coolant Failure and How to Prevent It", Sun Coolant
Control Inc., Southfield, Mich.

"Coolant Tripler Tool Life", Modern Machine Shop,
June 1979, pp. 140-141.

Cutting and Grinding Fluids; Selection and Application,
American Society of Tool and Manufacturing Engineers,
Dearborn, Mich. 1967.

Dinius, B., "How to Choose an In-Plant Oil Reclamation System",
Hydraulics and Pneumatics, July 1978, pp. 62-64.

"Economic Impact of the Proposed Illinois Special Waste Hauling
Regulations (R76-10)", Illinois Institute of Environmental
Quality, Project No. 80.089, IIEQ Document No. 77/26,
October 1977.

Electrostatic Separation of Solids from Liquids", Filtration &
Separation, March/April 1977, pp. 140-144.

Ford, Davis L. , and Elton, Richard L., "Removal of Oil and Grease
from Industrial Wastewaters", Chemical Engineering/Deskbook Issue,
October 17, 1977, pp. 49-56.
                               XIV-2

-------
Hura, LCdr Myron, USN and Mittleman, John,
"High Capacity Oil-Water Separator", Naval Engineers Journal,
December 1977, pp. 55-62.

Johnson, Ross E. Jr., Wastewater Treatment and Oil Reclamation
at General Motors, Sb. Catherines, pp. 345-357.

Kellogg, Jack, "Cutting Oil and Coolant Reclamation Pays Its
Way at Twin Disc".

Kelley, Ralph, "The Use of Cutting Fluids and Their Effect on
Cutting Tools and Grinding Wheels in Solving Production Problems",
Cincinnati Milacron/Products Division.

Koury, Anthony J., and Gabel, M.K., and Wijenayake, Anton P.,
"Effect of Solid Film Lubricants on Tool Life", Journal of the
American Society of Lubrication Engineers, June 1979 Volume 35,6.,
pp. 315-316, "329-338.

Luthy, Richard G., and Sellech, Robert E., and Galloway, Terry R.,
"Removal of Emulsified Oil with Organic Coagulants and Dissolved
Air Flotation", Journal WPCF, February 1978, pp. 331-346.

Lutz-Nagey, Robert C., "Detroit Experimenters Reveal New Ways
to Save Cutting Oil", Production Engineering, June 1977, pp. 54-55,

"Making Recycling Work for You Through Proper Process Selection",
IBID, p. 10.

McNutt, J.E. and Swalheim. D.A., "Recovery and Re-use of Chemicals
in Plating Effluents", AES Illustrated Lecture Series,
American Electroplaters Society, Inc., Winter Park, FL, 1975.

Miranda, Julio G., "Designing Parallel-Plates Separators",
Chemical Engineering, January 31, 1977.

"Oil Audit and Reuse Manual for the Industrial Plant", Illinois
Institute of Natural Resources, Project No. 80.085, Document
No. 78/35, November 1978.

"Oil/Water Splitter Snags Emulsified Oil", Chemical Engineering.
July 18, 1977, p. 77.

Quanstrom, Richard L., "Central Coolant Systems-Closing the Loop
on Metalworking Fluids", Lubrication Engineering, January 1977,
Volume 33,1, pp. 14-19.

Rasquin, Edgar A. and Lynn, Scott and Hanson, Donald N.,
"Vacuum Steam Stripping of Volatile, Sparing Soluble Organic
Compounds from Water Streams", Indo Eng. Chemical Fundam.,
Vol.  17, No. 3, 1978, pp. 170-174.

"Recycling Etchant for Printed Circuits", Metal Finishing,
Metals and Plastics Publications Inc., Hackensack, NJ,
March 1972, pp. 42-43.
                                XIV-3

-------
Reininga, O.G. and Wagner, R.H. and Bonewitz,
"Thermopure for Processing Water-Oil Emulsions",
Wire Journal, October 1976, pp. 48-53.

"Selection of Lubricants for Drawing and Cleaning", Daniel Brewer,
Ceramic Industry Magazine, June 1978, pp. 34-35.

Seng, W.C. and Kreutzer, G.M., "Resume of Total Operation of
Waste Treatment Facility for Animal and Vegetable Oil Refinery",
Reprinted from the Journal of the American Oil Chemists' Society,
Volume 52, No. 1, 1975, pp. 9A-13A.

Shah, B. and Langdon, W.,  and Wasan, D., "Regeneration of Fibrous
Bed Coalescers for Oil-Water Separation", Environmental Science
and Technology, Volume 11, No. 2, February 1977, pp. 167-170.

Sutcliffe, T. and Barber,  S.J., "How to Select a Water-Base
Coolant", American Machinist, April 1977.

"System Strips Solvents, Separates Solids Simultaneously",
Chemical Engineering, November 22, 1976, pp. 93-94.

Taylor, J.W., "Evaluation of Filter/Separators and Centrifuges
for Effects on Properties of Steam Turbine Lubricating Oils",
Journal of Testing and Evaluation, Volume 5, No. 5, September 1977,
pp. 401-405.

Teale, James M., "Fast Payout from In-Plant Recovery of Spent
Solvents", Chemical Engineering, January 31, 1977, pp. 98-100.

"The First Step-Reducing Waste Oil Generation", IBID, p. 16.

"Used Oil Recycling in Illinois", Data Book, Illinois Institue
of Natural Resources, Project No. 80.085, Document No. 78/34,
October, 1978.

"Waste Oil Reclamation", The Works Managers Guide to Working
Fluid Economy, Alfa-Laval No. 1B40494 E2.

"Waste Oil Recycling - Coming Up a Winner", Fluid and Lubricant
Ideas, Volume 2, Issue 3,  Summer 1979, p. 8.

Vucich, M.G., "Emulsion Control and Oil Recovery on the Lubricating
System of Double-Reduction Mills", Iron and Steel Engineer,
December 1976, pp. 29-38.
                                XIV-4

-------
PLATING AND COATING

Adams, F. "Getting the Most Out of Vacuum Metalizing",
Products Finishing, Gardner Publications Inc., Cincinnati,
Ohio, November,1917, pp. 43-51.

Allied Chemical Company and Aluminum Company of America,
"Chromic Acid Anodizing of Aluminum", AES Illustrated
Lecture Series, American Electroplaters Society, Inc.,
Winter Park, FL, 1973.

Baker, R. G. et al, "Gold Electroplating Part 2", AES
Illustrated Lecture Series, American Electroplaters Society,
Inc., Winter Park, FL, 1978.

Bellis, H.E. and Pearlstein, F.,  "Electroless Plating of Metals",
AES  Illustrated Lecture Series, American Electroplaters Society
Inc., Winter Park, FL, 1972.

"Cheminator", Chemical Engineering, McGraw Hill, New York, NY,
Septermber, 1975,  p.  26.

"Developments to Watch", Product  Engineering, Morgan-Grampian,
New  York, NY, October 1976, p.  5.

DiBari, G.A., "Practical Nickel Plating", AES Illustrated
Lecture Series, American Electroplaters Society, Inc., Winter
Park, FL, 1977.

Duva, R., "Gold Electroplating  Part  1", AES  Illustrated
Lecture Series, American Electroplaters Society, Inc., Winter
Park, FL, J977.

"Electroplating Engineering Handbook", Third Edition, edited
by A. Kenneth Graham, Van Nostrand Reinhold  Company, New York,
NY,  1971.

"Electroplating -  Fundamentals  of Surface Finishing", Frederick
A. Lowenheim, McGraw-Hill,  Inc.,  New York, NY,  1978.

General Motors  Research Laboratories,  "Factors  Influencing
Plate Distribution",  AES Illustrated Lecture Series,  American
Electroplaters  Society,  Inc., Winter Park, FL,  1975.

Halva, C.J. and Rothschild, B.F., "Plating and  Finishing  of
Printed Wiring/Circuit Boards", AES  Illustrated Lecture  Series,
American  Electroplaters  Society,  Inc., Winter Park,  FL,  1976.
                                XIV-5

-------
Hubbell, F.N., "Chemically Deposited Composites - A new Gener-
ation of Electroless Coatings", Plating and Surface Finishing,
American Electroplaters Society, E. Orange, NJ, Vol. 65, Dec.
1978, p. 48.

"Ion Transfer Method Developed for Metal Plating", Industrial
Finishing, Hitchcock Publishing Co., Wheaton, Ohio, April 1979,
p. 95.

Logozzo, Arthur W., "Hard Chromium Plating", AES Illustrated
Lecture Series, American Electroplaters Society, Inc., Winter
Park, FL, 1973.

MacDermid, Inc., "Chromate Conversion Coatings" AES Illus-
trated Lecture Series, American Electroplaters Society, Inc.,
Winter Park, FL, 1970.

Mazzeo, D.A., "Energy Conservation In Plating and Surface
Finishing", Plating and Surface Finishing, American Electroplaters
Society, Inc., Winter Park, FL, July, 1979, pp. 10-12.

M&T Chemical Inc., "Decorative Chromium Plating",  AES Illus-
trated Lecture Series, American Electroplaters Society, Inc.,
Winter Park, FL, 1972.

Mohler, J.B., "The Art and Science of Rinsing", AES Illustrated
Lecture Series, American Electroplaters Society, Inc., Winter
Park, FL, 1973.

Montgomery, D.C., "The Coloration of Anodic Coatings for
Architectural Applications by Using Organic Dyes", Plating
and Surface Finishing, American Electroplaters Society, E.
Orange, NJ, Vol. 65, Dec. 78, p. 48.

Ostraw, R. and Kessler, R.B., "A Technical and Economic Com-
parison of Cyanide and Cyanide-Free Zinc Plating", Plating,
American Electroplaters Society, Hackensack, NJ, April 1970.

Pearlstein, F., "Selection and Application of Inorganic Fini-
shes - Part 1", Plating and Surface Finishing, American Elec-
troplaters Society, E. Orange, NJ, Vol. 65, Dec. 1978., p. 32.

Pearlstein, F. et al, "Testing and Evaluation of Deposits",
AES Illutrated Lecture Series, American Electroplaters Society
Inc., Winter Park, FL, 1974.

Rajagopal, I., and Rajam, K.S., "A New Addition AgenV for
Lead Plating", Metal Finishing, Metals and Plastics Publi-
cation Inc., Hackensack, NJ, December, 1978.
                                XIV-6

-------
SURFACE PREPARATION

Axelson, William, "Specialized Cleaning Equipment Supports
Efficient Maintenance", Pit & Quauy, October 1976, pp. 95-98.

Bauks, S.V., and Dresser, K.J., Cleaning Alternatives to Solvent
Degreasing, EPA, December 7, 1878.

Jackson, Lloyd, C., "How to Select a Substrate Cleaning Solvent",
Adhesives Age, April 1977, pp. 23-31.

Jackson, Lloyd C., "Removal of Silicone Grease and Oil
Contaminants", Adhesives Age, April 1977, pp. 29-32.

Jackson, Lloyd C., "Solvent Cleaning Process Efficiency",
Adhesives Age, July 1976, pp. 31-34.

Maloney, J.E., "Low Temperature Cleaning", Metal Finishing,
June 1976, pp. 33-35.

Metal Cleaning Fundamentals, Materials and Methods, Oak'ite
Products, Inc., F 10646R13-379.

Metals Handbook, American Society for Metals, 8th Edition, Volume
2, "Heat Treating, Cleaning, and Finishing", 1964, pp. 307-314.

Mohler, J.B., "Guidelines for Cleaning Metal Parts", Plant
Engineering, October 2, 1975, pp. 93-95.

Obrzut, John J., "Metal Cleaning Bends with Social Presures",
Iron Age, February 17, 1974,, pp. 41-44.

Taller, R.A. and Koleske, J.V., "Energy Conservation in Metal
Pretreatment and Coating Operations", Metal Finishing,
August 1977, pp. 18-19.

Tonis, Paul G., "Try Steam Cleaning/Phosphatizing", Products
Finishing, January 1979, pp. 56-57.


SURFACE PREPARATION - ACID CLEANING

Frey, S.S. and Swalheim, D.A., "Cleaning and Pickling for
Electroplating", AES Illustrated Lecture Series, American
Electroplaters Society, Inc., Winter Park, FL, 1970.

Metals Handbook, American Society for Metals, 8th edition,
Volume 2, "Heat Treating, Cleaning and Finishing", 1964.

Rodzewich, Edward A., "Theory and Practice of Phosphating",
AES Illustrated Lecture Series, American Electroplaters
Society, Inc., Winter Park, FL, 1974.

Roebuck, A.H., "Safe Chemical Cleaning - The Organic Why",
Chemical Engineering, July 31, 1978, pp. 107-110.  '
                                 XIV-7

-------
SURFACE PREPARATION - ALKALINE CLEANING

Erichson, Paul R. and Throop, William M., "Alkaline Treatment
System Reduces Pollution Problems", Industrial Wastes, March/
April 1977.

Erichson, Paul R. and Throop, William M., "Improved Washing of
Machined Parts", Production Engineering, March 1977-

Graham, A. Kenneth, Electroplating Engineering Handbook, 1971,
pp. 152-176.

Metals Handbook, American Society for Metals, 8th Edition,
Volume 2, "Heat Treating, Cleaning and Finishing", 1964,
pp. 317-325.
SURFACE PREPARATION - EMULSION CLEANING

Connolly, James T., "Metal Cleaning with Emulsions - An Update",
Lubrication Engineering, December 1976, pp. 651-654.

Glover, Harry C., "Are Emulsified Solvents Safer Cleaners?",
Production Engineering, July 1978, pp. 41-43.

Metal Handbook, American Society for Metals, 8th Edition,
Volume 2, "Heat Treating, Cleaning and Finishing", 1964,
pp. 326-330.
SURFACE PREPARATION - VAPOR DECREASING

Bauks,  S.V. and Dresser, K.J., Solvent Degreasing Unit Operation
Report, EPA, September 17, 1979.

Metals Handbook, American Society for Metals, 8th Edition,
Volume 2,  "Heat Treating, Cleaning and Finishing", 1964,
pp. 334-340.

"Organic Solvent Cleaning-Background Information for Proposed
Standards", US EPA, EPA-450/2-78-045; May 1979.

Suprenant, K., "Vapor Degreasing or Alkaline Cleaning?",
Products Finishing, March 1979, pp. 67-71.
                                 XIV-8

-------
TREATMENT

Barrett, F., "The Electroflotation of Organic Wastes",
Chemistry and Industry, October 16, 1976, pp. 880-882.

Chin, D.T., and Echert, B., "Destruction of Cyanide Wastes
with a Packed-Bed Electrode", Plating and Surface Finishing,
October 1976, pp. 38-41.

DeLatour, Christopher, "Magnetic Separation in Water Pollution
Control", IEEE Transactions on Magnetics, Volume Mag-9, No. 3,
September 1973, p. 314.

"Development Document  for Proposed Exisiting Source Pretreat-
ment Standards for the Electroplating Point Source Category",
EPA 440/1-78/085.  United States Environmental Protection
Agency, Washington, DC, 1978.

"Economic Analysis of  Proposed Pretreatment Standards for
Existing Sources of the Electroplating Point Source Category",
EPA 230/1/78-001, United States Environmental Protection
Agency, Washington, DC. 1977.

"Electrotechnology Volume 1, Wastewater Treatment and Separation
Methods", Cheremisinoff, Paul N., King, John A., Oullette, Robert P.,
Ann Arbor Science Publishers, Inc., Ann Arbor, MI, 1978.

"Emerging Technologies for Treatment of Electroplating
Wastewaters", for presentation by Stinson, M.K., at AICHE
71st Annual Netting, Session 69, Miami Beach, Florida,
November 15, 1978.

Flynn, B.L. Jr., "Wet  Air Oxidation of Waste Streams", CEP,
April 1979, pp. 66-69.

Grutsch, James F., "Wastewater Treatment: The Electrical
Connection", Environmental Science and Technology, Volume  12,
No. 9, Sept. 1978, pp. 1022-1027.

Grutsch, James F., and Mallatt, R.C., "Optimizing Granular
Media Filtration", GEP, April 1977, pp. 57-66.

"Handbook of Environmental Data on Organic Chemicals", Karel
Verschueren, Van Nostrand Reinhold Company, New York, NY 1977.

Henry, Joseph D. Jr.,  Lowler, Lee F., and Kuo, C.H. Alex,
"A Solid/Liquid Separation Process Based on Cross Flow and
Electrofiltration", AIChE Journal, Volume 23, No. 6, November
1977, pp. 851-859.
                                 XIV-9

-------
Hochenberry, H.R. and Lieser, J.E., Practical Application
of Membrane Techniques of Waste Oil Treatmentf presented
at the 31st Annual Meeting in Philadelphia, Pennsylvania,
May 10-13, 1976, American Society of Lubrication Engineers,
Reprint Number 76-AM-28-2.

Humenich, Michael J. and Davis, Barry J., "High Rate
Filtration of Refinery Oily Wastewater Emulsions",
Journal WPCF, Agusut 1978, pp. 1953-1964.

"In Process Pollution Abatement - Upgrading Metal Finishing
Facilities to Reduce Pollution", EPA Technology Transfer Semi-
mar Publication, Environmental Protection Agency, July 1973.

Kaiser, Klaus L.E. and Lawrence, John, Polyelectrolytes;
Potential Chloroform Precursors, Environment Canada, Canada
Centre for Inland Waters, Burlington, Ontario, January 25, 1977.

Kitagewa, T. and Nishikawa, Y. and Frankenfeld, J.W. and Li,
N.N., "Wastewater Treatment by Liquid Membrane Process",
Environmental Science and Technology, Volume 11, No. 6,
June 1977, pp. 602-605.

Kolm, Henry H., "The Large-Scale Manipulation of Small Particles",
IEEE Transactions on Magnetics, Vol. Mag-11, No. 5, Sept. 1975,
pp. 1567-1569.

Lancy, L. E., "Metal Finishing Waste Treatment Aims Accomplished
by Process Changes", Chemical Engineering Progress Symposium
Series, Vol. 67, 1971, pp. 439-441.

Lancy, L.E. and Steward, F.A., "Disposal of Metal Finishing
Sludges - The Segregated Landfill Concept", Plating and Surface
Finishing, American Electroplaters Society, E. Orange, NJ,
Vol. 65, Dec. 1978. p. 14.

Lawes, B.C. and Stevens, W.F., "Treatment of Cyanide and
Chromate Rinses", AES Illustrated Lecture Series, American
Electroplaters Society, Inc., Winter Park, PL, 1972.

Lowder, L.R., "Modifications Improve Treatment of Plating Room
Wastes", Water and Sewage Works, Plenum Publishing Corp, New
York, NY, December, 1968. p. 581.

Oberteuffer, John A., "High Gradient Magnetic Separation",
IEEE Transaction on Magnetics, Volume Mag-9, No. 3,
September 1973, pp. 303-306.

Okamato, S., "Iron Hydroxide as Magnetic Scavengers",
Institute of Physical and Chemical Research, Waho-shi,
Saitama-hen, 351 Japan.
                                  XIV-10

-------
Oulman, Charles S. and Baumann, Robert E., "Polyelectrolyte
Coatings for Filter Media", Industrial Water Engineering,
May 1971, pp. 22-25.

Pietrzak, J., Unit Operation Discharge Summary for the Mechanical
Products Category, EPA, September 7, 1979.

Pinto, Steven, D., Ultrafiltration for Dewatering of Waste
Emulsified Oils,  Lubrication Challenges in Metalworking and
Processing Proceedings, First International Conference, IIT
Research Institute, Chicago, Illinois 60616, USA, June 7-9, 1978.

"Physiochemical Processes  for Water Quality Control", Wiley-
Interscience Series, Walter, J. Weber, Jr., John Wiley and Sons
Inc., New York, NY 1972.

"Pollution Control 1978",  Products Finishing, Gardner Publica-
tions, Inc., Cincinnati, Ohio, August, 1978, pp. 39-41.

Read, H.J., "Principles of Corrosion", AES Illustrated Lecture
Series, American  Electroplaters Society, Inc., Winter Park,
FL, 1971.

Sachs, T.R., "Diversified  Finisher. Handles Complex Waste
Treatment Problem", Plating and Surface Finishing, American
Electroplaters Society, E. Orange, NJ, Vol. 65, Dec. 1978, p. 36.

Shambaugh,Robert  T. and Melhyh, Peter B., "Removal of Heavy
Metals via Ozonation", Journal WPCF, Jan. 1978, pp. 113-121.

Staebler, C.J. and Simpers, B.F., "Corrosion Resistant Coatings
with Low Water Pollution Potential", presented at the EPA/AES
First Annual Conference on Advanced Pollution Control for the
Metal Finishing Industry,  Lake Buena Vista, FL, January 17-19, 1978,

Sundaram, T.R. and Santo,  J.E., "Removal of Suspended and
Colloidal Solids  from Waste Streams by the Use of Cross-Flow
Microfiltration", American Society of Mechanical Engineers,
77-ENAS-51.

"The Electrochemical Removal of Trace Metals for Metal Wastes
with Simultaneous Cyanide Destruction", for presentation by
H.S.A. Reactors Limited at the First annual EPA/AES Conference
on Advanced Pollution Control for the Metal Finishing Industry,
Dutch Inn, Lake Buena Vista, FL, Jan. 18, 1978.

Wahl, James R., Hayes, Thomas C., Kleper, Myles H., and Pinto,
Steven D., Ultrafiltration for Today's Oily Wastewaters;
A Survey of Current Ultrafiltration Systems, presented at the
34th Annual Purdue Industrial Waste Conference, May 8-10, 1979.
                                 XIV-11

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Ukawa, Hiroshi, Koboyashi, Kaseimaza, and Iwata, Minoru
"Analysis of Batch Electrokinetic Filtration", Journal of
Chemical Engineering of Japan, Volume 9, No. 5, 1976,
pp. 396-401.

Robinson, G.T., "Powder Coating Replaces Zinc Plating for
Pulleys", Products Finishing, Gardner Pubications Inc.,
Cincinnati, OH, Feb. 1974, pp. 79-81.

"Semiconductor Technique Now to Plate Auto Parts", Machine
Design, Penton Publishing, Cleveland, OH, p. 18.

Spooner, R.C., "Sulfuric Acid Anodizing of Aluminum and Its
Alloys", AES Illustrated Lecture Series, American Electro-
platers Society, Inc., Winter Park, FL, 1969.

Swalheim, D.A. et al, "Cyanide Copper Plating", AES Illustrated
Lecture Series, American Electroplaters Society, Inc., Winter
Park, FL, 1969.

Swalheium, D.A. et al, "Zinc and Cadmium Plating", AES
Illustrated Lecture Series, American Electroplaters Society,
Inc., Winter Park, FL.

"Wooing Detroit with Cheaper Plated Plastic", Business Week,
McGraw-Hill Inc., New York City, NY, May 9,  1977,  pp. 44c-44d.

Udylite Corporation, "Bright Acid Sulfate Copper Plating",
AES Illustrated Lecture Society, American Electroplaters Society,
Inc., Winter Park, FL, 1970.
                                XIV-12

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                         SECTION XV

                          GLOSSARY
Abrasive Belt Grinding - Roughing and/or finishing a workpiece by
     means of a power-driven belt coated with an abrasive, usually
     in particle form, which removes material by scratching the
     surface.

Abrasive Belt Polishing - Finishing a workpiece with a power-driven
     abrasive-coated belt in order to develop a very good finish.

Abrasive Blasting - (Surface treatment and cleaning.)  Using dry or
     wet abrasive particles under air pressure for short durations
     of time to clean a metal surface.

Abrasive Cutoff - Severing a workpiece by means of a thin abrasive
     wheel.

Abrasive Jet Machining - Removal of material from a workpiece by a
     high-speed stream of abrasive particles carried by gas from a
     nozzle.

Abrasive Machining - Used to accomplish heavy stock removal at high
     rates by use of a free-cutting grinding wheel.

Acceleration - See Activation.

Acceptance Testing - A test, or series of tests, and inspections
     that confirms product functioning in accordance with specified
     requirements.

Acetic Acid - (Ethanoic acid, vinegar acid, methanecarboxylic acid)
     CH3_COOH.  Glacial acetic acid is the pure compound  (99.8% rain.),
     as distinguished from the usual water solutions known as acetic
     acid.  Vinegar is a dilute acetic acid.

Acid Cleaning - Using any acid for the purpose of cleaning any mater-
     ial.  Some methods of acid cleaning are pickling and oxidizing.

Acid Dip - An acidic solution for activating the workpiece surface
     prior to electroplating in an acidic solution, especially after
     the workpiece has been processed in an alkaline solution.

Acidity - The quantitative capacity of aqueous solutions  to react
     with hydroxyl ions.  It is measured by titration with a standard
     solution of a base to a specified end point.  Usually expressed
     as milligrams per liter of calcium carbonate.
                                XV-1

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Act - Federal Water Pollution Control Act Amendments of  1972.

Activitated Sludge Process - Removes organic matter from sewage  by
     saturating it with air and biological active  sludge.

Activation - The process of treating a substance by heat,  radiation
     or the presence of another substance so that  the  first mentioned
     substance will undergo chemical or physical change  more  rapidly
     or completely.

Additive Circuitry - 1.  Full - Circuitry produced by  the  buildup of
     an electroless copper pattern upon an unclad  board.   2.  Semi -
     Circuitry produced by the selective "quick" etch  of  an electro-
     less layer; this copper layer was previously  deposited on an
     unclad board.

Administrator - Means the Administrator of the United  States  Environ-
     mental Protection Agency.

Adsorption - The adhesion of an extremely thin layer of  molecules
     (as of gas, solids or liquids) to the surface of  solid   or
     liquids with which they are in contact.

Aerobic - Living, active, or occurring only in the presence of oxygen.

Aerobic Biological Oxidation - Any waste treatment process utilizing
     organisms in the presence of air or oxygen to reduce  the pol-
     lution load or oxygen demand of organic substance in  water.

Aerobic Digestion - (Sludge Processing)  The biochemical decomposition
     of organic matter, by organisms living or active only in the
     presence of oxygen, which results in the formation  of mineral and
     simpler organic compounds.

Aging - The change in properties (eg. increase in  tensile  strength and
     hardness) that occurs in certain metals at atmospheric temperature
     after heat treatment.

Agitation of Parts - The irregular movement given  to parts when  they
     have been submerged in a plating or rinse solution.

Air Agitation - The agitation of a liquid medium through the  use of
     air pressure injected into the liquid.

Air Flotation - See Flotation

Air Pollution - The presence in the outdoor (ambient)  atmosphere of one
     air pollutants or any combination thereof in  such quantities and
     of such characteristics and duration as to be, or be  likely to be,
     injurious to public welfare, to the health of human,  plant  or
     animal life, or to property, or as unreasonably to  interfere with
     the enjoyment of life and property.
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Air-Liquid Interface - The boundary layer between the air and the
     liquid in which mass transfer is diffusion controlled.

Aldehydes Group - A group of various highly reactive compounds
     typified by actaldehyde and characterized by the group CHO.

Algicides - Chemicals for preventing the growth of algae.

Alkaline Cleaning - A process for cleaning basis material where
     mineral and animal fats and oils must be removed from the
     surface.  Solutions at high temperatures containing casutic
     soda, soda ash, alkaline silicates and alkaline phosphates
     are commonly used.

Alkalinity - The capacity of water to neutralize acids, a property
     imparted by the water's content of carbonates, bicarbonates,
     hydroxides, and occasionally borates, silicates, and phosphates.

Alloy Steels - Steels with carbon content between 0.1% to 1.1% and
     containing elements such as nickel, chromium, molybdenum and
     vanadium.  (The total of all such alloying elements in these type
     steels is usually less than 5%.)

Aluminizing - Forming an aluminum or aluminum alloy coating on a metal
     by hot dipping, hot spraying or diffusion.

Amines - A class of organic compounds of nitrogen that may be considered
     as derived from ammonia (NH^) by replacing one or more of the
     hydrogen atoms by organic radicals, such as CH^ or Cj>H_5, as in
     methylamine and aniline.  The former is a gas at ordinary tempera-
     ture and pressure, but other amines are liquids or solids.  All
     amines are basic in nature and usually combine readily with hydro-
     chloric or other strong acids to form salts.

Anaerobic Biological Treatment - Any waste treatment process utilizing
     anaerobic or facultative organisms in the absence of air to
     reduce the organic matter in water.

Anaerobic Digestion - The process of allowing sludges to decompose
     naturally in heated tanks without a supply of oxygen.

Anaerobic Waste Treatment - (Sludge Processing)' Waste stabilization
     brought about through the action of microorganisms in the absence
     of air or elemental oxygen.

Anhydrous - Containing no water.

Anions - The negatively charged ions in solution, e.g., hydroxyl.

Annealing - A process for preventing brittleness in a metal part.
     The process consists of raising the temperature of the metal
     to a pre-established level and slowly cooling the steel at  a
     prescribed rate.
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Annual Capital Recovery Cost - Allocates the  initial  investment  and
     the interest to the total operating cost.  The capital  recovery
     cost is equal to the initial investment  multiplied  by  the capital
     recovery factor.

Anode - The positively charged electrode in an electrochemical process.

Anodizing - The production of a protective oxide film on  aluminum  or
     other light metal by passing a high voltage electric current
     through a bath in which the metal is suspended.

Aquifer - Water bearing stratum.

Ash - The solid residue left after complete combustion.

Assembly - The fitting together of manufactured parts into  a  complete
     machine, structure, or unit of a machine.

Atmospheric Evaporation - Evaporation at ambient pressure utilizing
     a tower filled with packing material.  Air is drawn  in  from
     the bottom of the tower and evaporates feed material entering
     from the top.  There is no recovery of the vapors.

Atomic Absorption - Quantitative chemical instrumentation used for the
     analysis of elemental constituents.

Automatic Plating - 1.  Full - Plating in which the workpieces are
     automatically conveyed through successive cleaning  and plating
     tanks.  2.  Semi - Plating in which the  workpieces  are conveyed
     automatically through only one plating tank.

Austempering - Heat treating process to obtain greater toughness and
     ducticity in certain high-carbon steels.  The process  is charac-
     terized by interrupted quenching and results in the  formation of
     bainite grain structure.

Austenitizing - Heating a steel to a temperature at which the structure
     transforms to a solution of one or more  elements in  face-centered
     cubic iron.  Usually performed as the essential preliminary of
     heat treatment, in order to get the various alloying elements
     into solid solution.

Barrel Finishing - The process of polishing a workpiece  using a  rotat-
     ing or vibrating container and abrasive  grains or other  polishing
     materials to achieve the desired surface appearance.

Barrel Plating - Electroplating of workpieces in barrels  (bulk).

Basis Meta-1 or Material - That substance of which the workpieces are
     made and that receives the electroplate  and the treatments  in
     preparation for plating.
                              XV-4

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Batch Treatment - A waste treatment method where wastewater  is collect-
     ed over a period of time and then treated prior to discharge.

Bending - Turning or forcing by a brake press or other device from a
     straight or even to a curved or angular condition.

Best Available Technology Economically Achievable  (BAT) - Level of
     technology applicable to effluent limitations to be achieved
     by 1984 for industrial discharges to surface waters as  defined
     by Section 301(b)  (2) (A) of the Act.

Best Practicable Control Technology Currently Available - Level of
     technology applicable to effluent limitations to be achieved
     for industrial discharges to surface waters as defined  by
     Section 301 (b) (1) (A) of the Act.

Biochemical Oxygen Demand (BOD) - The amount of oxygen in milligrams
     per liter used by  microorganisms to consume biodegradable organics
     in wastewater under aerobic conditions.

Biodegradability - The  susceptibility of a substance to decomposition
     by microorganisms; specifically, the rate at which compounds may
     be chemically broken down by bacteria and/or natural environmental
     factors.

Blanking - Cutting desired shapes out of sheet metal by means of dies.

Slowdown - The minimum  discharge of recirculating water for  the purpose
     of discharging materials contained in the water, the further build-
     up of which would  cause concentration in amounts exceeding limits
     established by best engineering practice.

BODS - The five-day Biochemical Oxygen Demand (BODS) is the  quantity
     of oxygen used by  bacteria in consuming organic matter  in a sample
     of wastewater over a five-day period.  BOD from the standard five-
     day test equals about two-thirds of the total BOD.  See Biochem-
     ical Oxygen Demand.

Bonding - The process of uniting using an adhesive or fusible
     ingredient.

Boring - Enlarging a hole by removing metal with a single or occasion-
     ally a multiple point cutting tool moving parallel to  the axis  of
     rotation of the work or tool.  1.  Single-Point Boring  - Cutting
     with a single-point tool.  2.  Precision Boring - Cutting to
     tolerances held within narrow limits.  3.  Gun Boring  - Cutting
     of deep holes.  4.  Jig Boring - Cutting of high-precision and
     accurate location  holes.  5.  Groove Boring - Cutting  accurate
     recesses in hole walls.
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Brazing - Joining metals by flowing a thin layer, capillary  thickness,
     of non-ferrous filler metal into the space between them.  Bonding
     results from the intimate contact produced by the dissolution  of
     a small amount of base metal in the molten filler metal, without
     fusion of the base metal.  The term brazing is used where the
     temperature exceeds 425°C(800°F).

Bright Dipping - The immersion of all or part of a workpiece  in a
     media designed to clean or brighten the surface and leave a
     protective surface coating on the workpiece.

Brine - An aqueous salt solution.

Broaching - Cutting with a tool which consists of a bar having a
     single edge or a series of cutting edges (i.e., teeth) on its
     surface.  The cutting edges of multiple-tooth, or successive
     single-tooth, broaches increase in size and/or change in shape.
     The broach cuts in a straight line or axial direction when
     relative motion is produced in relation to the workpiece, which
     may also be rotating.  The entire cut is made in single or
     multiple passes over the workpiece to shape the required surface
     contour.  1.  Pull Broaching - Tool pulled through or over work-
     piece.  2.  Push Broaching - Tool pushed over or through work-
     piece.  3.  Chain Broaching - A continuous high production
     surface broach.  4.  Tunnel Broaching - Work travels through an
     enclosed area containing broach inserts.

Bromine Water - A nonmetallic halogen liquid, normally deep red,
     corrosive and toxic, which is used as an oxidizing agent.

Buffing - An operation to provide a high luster to a surface.  The
     operation, which is not intended to remove much material,
     usually follows polishing.

Buffing Compounds - Abrasive contained by a liquid or solid binder
     composed of fatty acids, grease, or tallow.  The binder serves
     as lubricant, coolant, and an adhesive of the abrasive to the
     buffing wheel.

Burnishing - Finish sizing and smooth finishing of a workpiece
     (previously machined or ground) by displacement, rather than
     removal, of minute surface irregularities with smooth point or
     line-contact, fixed or rotating tools.

Calendering - Process of forming a continuous sheet by squeezing the
     material between two or more parallel rolls to impart the desired
     finish or to insure uniform thickness.

Calibration - The application of thermal, electrical, or mechanical
     energy to set or establish reference points for a part, assem-
     bly or complete unit.
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Calibration Equipment - Equipment used for calibration of  instruments.

Capital Recovery Costs - Allocates the initial investemnt  and  the  inter-
     est to the total operating cost.  The capital recovery cost is
     equal to the initial investment multiplied by the capital recovery
     factor.

Capital Recovery Factor - Capital Recover Factor is defined as:
     i + i/(a - 1) where i = interest rate, a = (1 + i) to the power n,
     n = interest period in years.

Captive Operation - A manufacturing operation carried out  in a facility
     to support subsequent manufacturing, fabrication, or  assembly
     operations.

Carbides - Usually refers to the general class of pressed  and  sintered
     tungsten carbide cutting tools which contain tungsten carbide plus
     smaller amounts of titanium and tantalum carbides along with
     cobalt which acts as a binder.  (It is also used to describe hard
     compounds in steels and cast irons.)

Carbon Adsorption - Activated carbon contained in a vessel and
     installed in either a gas or liquid stream to remove  organic
     contaminates.  Carbon is regenerable when subject to  steam which
     forces contaminant to desorb from media.

Carbon Bed Catalytic Destruction - A non-electrolytic process  for the
     catalytic oxidation of cyanide wastes using filters filled with
     low-temperature coke.

Carbon Steels - Steel which owes its properties chiefly to various
     percentage of carbon without substantial amounts of other alloying
     elements.

Carbonate - A compound containing the acid radical of carbonic acid
     (C0_3 group) .

Carbonitriding - Process for case or core hardening of metals.  The
     heated metals absorb carbon in a gaseous atmosphere.

Carburizing - (Physical Property Modification) Increasing  the  carbon
     content of a metal by heating with a carburizing medium (which
     may be solid, liquid or gas) usually for the purpose  of producing
     a hardened surface by subsequent quenching.

Carcinogen - Substance which causes cancerous growth.

Case Hardening - A heat treating method by which the surface layer of
     alloys is made substantially harder than the interior.  (Carburiz-
     ing and nitriding are common ways of case hardening steels.)

Cast - A state of the substance after solidification of the molten
     substance.
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Casthquse - The facility which melts metal, holds it  in  furnaces  for
     degassing (fluxing) and alloying and then casts  the metal  into
     pigs, ingots, billets, rod, etc.

Casting - The operation of pouring molten metal into  a mold.

Catalytic Bath - A bath containing a substance used to accelerate  the
     rate of chemical reaction.

Category - Also point source category.  A segment of  industry for
     which a set of effluent limitations has been established.

Cathode - The negatively charged electrode in an electrochemical
     process.

Cation - The positively charged ions in a solution.

Caustic - Capable of destroying or eating away by chemical action.
     Applies to strong bases and characterized by the presence  of
     hydroxyl ions in solution.

Caustic Soda - Sodium hydroxide, NaOH, whose solution in water  is
     strongly alkaline.

Cementation - The electrochemical reduction of metal  ions by contact
     with a metal of higher oxidation potential.  It  is  usually used
     for the simultaneous recovery of copper and reduction of
     hexavalent chromium with the aid of scrap iron.

Centerless Grinding - Grinding the outside or inside  of  a workpiece
     mounted on rollers rather than on centers.  The  workpiece  may be
     in the form of a cylinder or the frustrum of a cone.

Central Treatment Facility - Treatment plant which co-treats process
     wastewaters from more than one manufacturing operation or  co-
     treats process wastewaters with non-contact cooling water, or
     with non-process wastewaters (e.g., utility blowdown, miscellan-
     eous runoff, etc.).

Centrifugation - An oil recovery step employing a centrifuge to remove
     water from waste oil.

Centrifuge - A device having a rotating container in  which centrifugal
     force separates substances of differing densities.

Chelated Compound - A compound in which the metal is  contained  as  an
     integral part of a ring structure and is not readily ionized.
                                XV-8

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Chelating Agent - A coordinate compound in which a central atom
     (usually a metal) is joined by covalent bonds to two or more
     other molecules or ions  (called ligands) so that heterocyclic
     rings are formed with the central  (metal) atom as part of each
     ring.  Thus, the compound is suspending the metal in solution.

Chemical Brightening - Process utilizing an addition agent that leads
     to the formation of a bright plate or that improves the brightness
     of the deposit.

Chemical Deposition - Process used to deposit a metal oxide on a
     substrate.  The film is  formed by  hydrolysis of a mixture of
     chlorides at the hot surface of the substrate.  Careful control
     of the water mixture insures that  the oxide is formed on the
     substrate surface.

Chemical Etching - To dissolve a part of the surface of a metal or
     all of the metal laminated to a base.

Chemical Machining - Production of derived shapes and dimensions
     through selective or overall removal of metal by controlled
     chemical attack or etching.

Chemical Metal Coloring - The production of desired colors on metal
     surfaces by appropriate  chemical or electrochemical action.

Chemical Milling - Removing large amounts of stock by etching
     selected areas of complex workpieces.  This process entails
     cleaning, masking, etching, and demasking.

Chemical Oxidation -  (Including Cyanide) The addition of chemical
     agents to wastewater for the purpose of oxidizing pollutant
     material.

Chemical Oxygen Demand (COD)  - The amount of oxygen in milligrams per
     liter to oxidize both organic and  oxidizable inorganic compounds.

Chemical Precipitation - A chemical process in which a chemical in
     solution reacts with another chemical introduced to that solution
     to form a third substance which is partially or mainly insoluble
     and, therefore, appears  as a solid.

Chemical Recovery Systems - Chemical treatment to remove metal or
     other materials from wastewater for later reuse.

Chemical Reduction - A chemical reaction in which one or more electrons
     are transferred to the chemical being reduced from the chemical
     initiating the transfer  (reducing  agent).
                               XV-9

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Chemical Treatment - Treating contaminated water by  chemical  means.

Chip Dragout - Cutting fluid or oil adhering to metal  chips  from  a
     machining operation.

Chlorinated Hydrocarbons - Organic compounds containing  chlorine
     such as many insecticides.

Chlorination - The application of chlorine to water  generally for
     purposes of disinfection, but frequently for accomplishing
     other biological or chemical results.

Chromate Conversion Coating - Protective coating formed  by immersing
     metal in an aqueous acidified solution consisting substantially
     of chromic acid or water soluble salts of chromic acid  together
     with various catalysts or activators.

Chromatizing - To treat or impregnate with a chromate  (salt of ester
     of chromic acid) or dichromate, especially with potassium
     dichromate-

Chrome-Pickle Process - Forming a corrosion-resistant oxide  film on
     the surface of magnesium base metals by immersion in a bath of
     an alkaline bichromate.

Clarification - The composite wastewater treatment process consisting
     of flash mixing of coagulants, pH adjusting chemicals, and/or
     polyelectrolytes, flocculation, and sedimentation.

Clarifier - A unit which provides for settling and removal of solids
     from wastewater.

Cleaning - The removal of soil and dirt (including grit  and grease)
     from a workpiece using water with or without a  detergent or
     other dispersing agent.

See  Vapor Degreasing
     Solvent Cleaning
     Contaminant Factor
     Acid Cleaning
     Emulsion Cleaning
     Alkaline Cleaning
     Salt Bath Descaling
     Pickling
     Passivate
     Abrasive Blast Cleaning
     Sonic and Ultrasonic Cleaning

Closed-Loop Evaporation System - A system used for the recovery of
     chemicals and water from a chemical finishing process.   An
     evaporator concentrates flow from the rinse water holding tank.
     The concentrated rinse solution is returned to  the  bath, and
     distilled water is returned to the final rinse  tank.  The
     system is designed for recovering 100 percent of chemicals nor-
     mally lost in dragout for reuse in the process.


                             XV-10

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Closed Loop Rinsing - The recirculation of rinse water without the
     introduction of additional makeup water.

Coagulation - A chemical reaction in which polyvalent ions neutralize
     the repulsive charges surrounding colloidal particles.

Coating  See   Aluminum Coating
               Hot Dip Coating
               Ceramic Coating
               Phosphate Coating
               Chromate Conversion Coating
               Rust-Preventive Compounds
               Porcelain Enameling

COD - See Chemical Oxygen Demand

Cold Drawing - A process of forcing material through dies or other
     mandrels to produce wire, rod, tubular and some bars.

Cold Heading - A method of forcing metal to flow cold into enlarged
     sections by endwise squeezing.  Typical coldheaded parts are
     standard screws, bolts under 1 in. diameter and a large variety
     of machine parts such as small gears with stems.

Cold Rolling - A process of forcing material through rollers to produce
     bars and sheet stock.

Colorimetric - A procedure for establishing the concentration of impur-
     itites in water by comparing its color to a set of known color
     impurity standards.

Common Metals - Copper, nickel, chromium, zinc, tin, lead, cadmium,
     iron, aluminum, or any combination thereof.

Compatible Pollutants - Those pollutants which can be adequately
     treated in publicly-owned treatment works without upsetting
     the treatment process.

Complexing Agent - A compound that will join with a metal to form
     an ion which has a molecular structure consisting of a central
     atom (the metal) bonded to other atoms by coordinate covalent
     bonds.

Composite Wastewater Sample - A combination of individual samples of
     water or wastewater taken at selected intervals, generally hourly
     for some specified period, to minimize the effect of the varia-
     bility of the individual sample.  Individual samples may have
     equal volume or may be proportioned to the flow at time of
     sampling.

Conductance - See Electrical Conductivity.
                               XV-11

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Conductivity Surface - A surface that can transfer heat or electricity.

Conductivity Meter - An instrument which displays a quantitative
     indication of conductance.

Contact Water - See Process Wastewater.

Contamination - Intrusion of undesirable elements.

Continuous Treatment - Treatment of waste streams operating without
     interruption as opposed to batch treatment; sometimes referred
     to as flow=through treatment.

Contractor Removal - Disposal of oils, spent solutions, or sludge
     by a scavenger service.

Conversion Coating - A coating produced by chemical or electrochemical
     treatment of a metallic surface that gives a superficial layer
     containing a compound of the metal.  For example, chromate coating
     on zinc and cadmium, oxide coatings on steel.

Coolant - See Cutting Fluids.

Cooling Water - Water which is used to absorb and transport heat
     generated in a process or machinery.

Copper Flash - Quick preliminary deposition of copper for making
     surface acceptable for subsequent plating.

Coprecipitation of Metals - Precipitation of a metal with another
     metal.

Corrosion Resistant Steels - A term often used to describe the stain-
     less steels with high nickel and chromium alloy content.

Cost of Capital - Capital recovery costs minus the depreciation.

Counterboring - Removal of material to enlarge a hole for part of
     its depth with a rotary, pilot guided, end cutting tool having
     two or  more cutting lips and usually having straight or helical
     flutes  for the passage of chips and the admission of a cutting
     fluid.

Countercurrent Rinsing - Rinsing of parts in such a manner that the
     rinse water is removed from tank to tank counter to the flow of
     parts being rinsed.

Countersinking - Beveling or tapering the work material around the
     periphery of a hole creating a concentric surface at an angle
     less than 90 degrees with the centerline of the hole for the
     purpose of chamfering holes or recessing screw and rivet heads.
                               XV-12

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Crystalline Solid - A substance with an ordered structure, such as
     a crystal.

Crystallization - 1.  Process used to manufacture semiconductors
     in the electronics industry.  2.  A means of concentrating
     pollutants in wastewaters by crystallizing out pure water.

Curcumine or Carmine Method - A standard method of measuring the
     concentration of boron (B) within a solution.

Cutting Fluids - Lubricants employed to ease metal and machining
     operations, produce surface smoothness and extend tool life
     by providing lubricity and cooling.  Fluids can be emulsified
     oils in water, straight mineral oils when better smoothness
     and accuracy are required, or blends of both.

Cyaniding - A process of case hardening an iron-base alloy by the
     simultaneous absorption of carbon and nitrogen by heating in a
     cyanide salt.  Cyaniding is usually followed by quenching to
     produce a hard case.

Cyclone Separator - A device which removes entrained solids from gas
     streams.

Dead Rinse - A rinse step in which water is not replenished or dis-
     charged.

Deburring - Removal of burrs or sharp edges from parts by filing,
     grinding or rolling the work in a barrel with abrasives sus-
     pended in a suitable medium.

Deep Bed Filtration - The common removal of suspended solids from
     wastewater streams by filtering through a relatively deep
     (0.3-0.9 m) granular bed.  The porous bed formed by the granular
     media can be designed to remove practically all suspended
     particles by physical-chemical effects.

Degassing - (Fluxing)  The removal of hydrogen and other impurities
     from molten primary aluminum in a casthouse holding furnace by
     injecting chlorine gas (often with nitrogen and carbon).

Degradable - That which can be reduced, broken down or chemically
     separated.

Demineralization - The removal from water of mineral contaminants
     usually present in ionized form.  The methods used  include  ion-
     exchange techniques, flash distillation or electrolysis.
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Denitrification (Biological) - The reduction of nitrates  to nitrogen
     gas by bacteria.

Deoxidizing - The removal of an oxide film from an alloy  such as
     aluminum oxide.

Depreciation - Decline in value of a capital asset caused either by use
     or by obsolescence.

Descaling - The removal of scale and metallic oxides from the surface
     of a metal by mechanical or chemical means.  The former includes
     the use of steam, scale-breakers and chipping tools, the latter
     method includes pickling in acid solutions.

Desmutting - The removal of smut (matter that soils or blackens)
     generally by chemical action.

Dewatering - (Sludge Processing)  Removing water from sludge.

Diaminobenzidene - A chemical used in the standard method of measuring
     the concentrations of selenium in a solution.

Dibasic Acid - An acid capable of donating two protons (hydrogen
     ions).

Dichromate Reflux - A standard method of measuring the chemical
     oxygen demand of a solution.

Die Casting - (hot chamber, vacuum, pressure)  Casting are produced
     by forcing molten metal under pressure into metal mold called
     dies.  In hot chamber machines, the pressure cylinder is sub-
     merged in the molten metal resulting in a minimum of time and
     metal cooling during casting.  Vacuum feed machines use a
     vacuum to draw a measured amount of melt from the molten bath
     into the feed chamber.  Pressure feed systems use a hydraulic
     or pneumatic cylinder to feed molten metal to the die.

Digestion - A standard method of measuring organic nitrogen.

Dipping - Material coating by briefly immersing parts in a molten
     bath, solution or suspension.

Direct Labor Costs - Salaries, wages and other direct compensations
     earned by the employee.

Discharge of Pollutant(s) - 1.  The addition of any pollutant to
     navigable waters from any point source.  2.  Any addition of any
     pollutant to the waters of the continguous zone or the ocean
     from any point source, other than from a vessel or other floating
     craft.  The term "discharge" includes either the discharge of a
     single pollutant or the discharge of multiple pollutants.
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Dispersed-air Flotation - Separation of low density  contaminants  from
     water using minute air bubbles attached  to  individual particles
     to provide or increase the buoyancy of the  particle.  The bubbles
     are generated by introducing air through a  revolving  impeller  or
     porous media.

Dissolved-air Floatation - Separation of low density  contaminants from
     water using minute air bubbles attached  to  individual particles
     to provide or increase the buoyancy of the  particle.  The air  is
     put into solution under elevated pressure and later released under
     atmospheric pressure or put into solution by aeration at atmos-
     pheric pressure and then released under  a vacuum.

Dissolved Oxygen (DO) - The oxygen dissolved  in  sewage, water, or other
     liquid, usually expressed in milligrams per liter or  percent of
     saturation.  It is the test used in BOD determination.

Distillation - Vaporization of a liquid followed by  condensation  of
     the vapor.

Distillation Refining - A metal with an impurity having a  higher  vapor
     pressure than the base metal can be refined by  heating  the metal
     to the point where the impurity vaporizes.

Distillation-Silver Nitrate Titration - A standard method  of measuring
     the concentration of cyanides in a solution.

Distillation-SPADNS - A standard method of measuring  the concentration
     of fluoride in a solution.

Dollar Base - A period in time in which all costs are related.  Invest-
     ment costs are related by the Sewage Treatment  Plant  Construction
     Cost Index.  Supply costs are related by the "Industrial Commod-
     ities" Wholesale Price Index.

Drag-in - Water or solution carried into another solution  by the  work
     and the associated handling equipment.

Dragout - The solution that adheres to the objects removed from a bath,
     more precisely defined as that solution  which is carried past  the
     edge of the tank.

Dragout Reduction - Minimization of the amount of material  (bath  or
     solution) removed from a process tank by adherring to the part
     or its transfer device.

Drainage Phase - Period in which the excess plating  solution adhering
     to the part or workpiece is allowed to drain off.
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Drawing - Reduction of cross section area and  increasing  the  length
     by pulling metal through conical taper dies.

Drawing Compounds - See Wire Forming Lubricants.

Drilling - Hole making with a rotary, end-cutting  tool having  one  or
     more cutting lips and one or more helical or  straight  flutes  or
     tubes for the ejection of chips and the passage of a cutting
     fluid.  1.  Center Drilling - Drilling a  conical hole  in  the
     end of a workpiece.  2.  Core Drilling -  Enlarging a hole with
     a chamer-edged, multiple-flute drill.  3.  Spade Drilling -
     Drilling with a flat blade drill tip.  4.  Step Drilling  - Using
     a multiple diameter drill.  5.  Gun Drilling  - Using special
     straight flute drills with a single lip and cutting  fluid at  high
     pressures for deep hole drilling.  6.  Oil Hole or Pressurized
     Coolant Drilling - Using a drill with one or  more continuous
     holes through its body and shank to permit the passage of a
     high pressure cutting fluid which emerges at  the drill point
     and ejects chips.

Drip Station - Empty tank over which parts are allowed to drain
     freely to decrease end dragout.

Drip Time - The period during which a part is  suspended over baths
     in order to allow the excessive dragout to drain off.

Drying Beds - Areas for dewatering of sludge by evaporation and
     seepage.

EDTA Titration - EDTA - ethylenediamine tetraacetic acid  ( or  its
     salts).  A standard method of measuring the hardness of a
     solution.

Effluent - The water and the quantities, rates, and concentrations
     of chemical, physical, biological, and other  constituents
     which are discharged from point sources.

Effluent Limitation - Any restriction (including schedules of  compli-
     ance) established by a state or the federal EPA on quantites,
     rates, and concentrations of chemical, physical, biological,
     and other constituents which are discharged from point sources
     into naviigable waters, the waters of the contiguous zone, or
     the ocean.

Electrical Conductivity - The property which allows an electric current
     to flow when a potential difference is applied.  It  is the re-
     ciprocal of the resistance in ohms measured between  opposite
     faces of a centimeter cube of an aqueous  solution at a specified
     temperature.  It is expressed as raicromhos per centimeter at
     temperature degrees Celsius.
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Electrical Discharge Machining - Metal removal by a rapid  spark dis-
     charge between different polarity electrodes, one  the workpiece
     and the other the tool separated by a gap distance of 0.0005  in.
     to 0.035 in.  The gap is filled with dielectric  fluid and metal
     particles which are melted, in part vaporized and  expelled from
     the gap.

Electrobrightening - A process of reversed electro-deposition which
     results in anodic metal taking a high polish.

Electrochemical Machining (ECM) - A machining process whereby the  part
     to be machined is made the anode and a shaped cathode is maintain-
     ed in close proximity to the work.  Electrolyte  is pumped between
     the electrodes and a potential applied with the  result  that metal
     is rapidly dissolved from the workpiece in a selective  manner and
     the shape produced on the workpiece complements  that of the
     cathode.

Electrocleaning - The process of anodic removal of surface oxides  and
     scale from a workpiece.

Electrode -  Conducting material for passing electric current into or
     out of a solution by adding electrons to or taking electrons
     from ions in the solution.

Electrodialysis - A treatment process that uses electrical current and
     and arrangement of permeable membranes to separate soluble minerals
     from water.  Often used to desalinate salt or brackish  water.

Electroless Plating - Deposition of a metallic coating  by a  control-
     led chemical reduction that is catalyzed by the  metal or alloy
     being deposited.

Electrolysis - The chemical decomposition by an electric current of
     a substance in a dissolved or molten state.

Electrolyte - A liquid, most often a solution, that will conduct an
     electric current.

Electrolytic Cell - A unit apparatus in which electrochemical react-
     ions are produced by applying electrical energy  or which supplies
     electrical energy as a result of chemical reactions and which
     includes two or more electrodes and one or more  electrolytes  con-
     tained in a suitable vessel.

Electrolytic Decomposition - An electrochemical treatment  used for the
     oxidation of cyanides.  The method is practical  and economical
     when applied to concentrated solutions such as contaminated baths,
     cyanide dips, stripping solutions, and concentrated rinses.
     Electrolysis is carried out at a current density of 35  amp/sq.
     ft. at the anode and 70 amp/sq. ft. at the cathode.  Metal is
     deposited at the cathode and can be reclaimed.
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Electrolytic Oxidation - A reaction by an electrolyte  in which  there
     is an increase in valence resulting from a loss of electrons.

Electrolytic Reduction - A reaction in which there  is  a decrease  in
     valence resulting from a gain in electrons.

Electrolytic Refining - The method of producing pure metals  by  making
     the impure metal the anode in an electrolytic  cell and  depositing
     a pure cathode.  The impurities either remain  undissolved  at  the
     anode or pass into solutions in the electrolyte.

Electrometallurgical Process - The application of electric current to
     a metallurgical process either for electrolytic deposition or as
     a source of heat.

Electrometric Titration - A standard method of measuring the  alkalin-
     ity of a solution.

Electron Beam Machining - The process of removing material from a
     workpiece by a high velocity focused stream of electrons which
     melt and vaporize the workpiece at the point of impingerent.

Electroplating - The production of a thin coating of one metal  on a
     surface by electrodeposition*

Electropolishing - Electrolytic corrosion process that increases the
     percentage of specular reflectance from a metallic surface.

Embossing - Raising a design in relief against a surface.

Emulsified Oil and Grease - An oil or grease dispersed in an  immis-
     cible liquid usually in droplets of larger than colloidal  size.
     In general suspension of oil or grease within  another liquid
     (usually water).

Emulsifying Agent - A material that increases the stability  of  a
     dispersion of one liquid in another.

Emulsion Breaking - Decreasing the stability of dispersion of one
     liquid in another.

Emulsion Cleaning - A cleaning process using organic solvents dis-
     persed in an aqueous medium with the aid of an emulsifying agent.

End-of-Pipe Treatment - The reduction and/or removal of pollutants by
     treatment just prior to actual discharge.

Environmental Protection Agency - the United States Environmental
     Protection Agency.
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EPA - See Environmental Protection Agency.

Equalization -  (Continuous Flow) - The balancing of flow or pollutant
     load using a holding tank for a system that has widely varying
     inflow rates.

Equilibrium Concentration - A state at which the concentration of
     chemicals in a solution remain in a constant proportion to one
     another.

Ester - An organic compound corresponding in structure to a salt in
     inorganic chemistry.  Esters are considered as derived from the
     acids by the exchange of the replaceable hydrogen of the latter
     for an organic alkyl radical.  Esters are not ionic compounds,
     but salts usually are.

Etchant - The material used in the chemical process of removing glass
     fibers and epoxy between neighboring conductor layers of a PC
     board for a given distance.

Etching - A process where material is removed by chemical action.

Evaporation Ponds - Liquid waste disposal areas that allow the liquid
     to vaporize to cool discharge water temperatures or to thicken
     sludge.

Excess Capacity Factor - A multiplier on process size to account for
     shutdown for cleaning and maintenance.

Extrusion - A material that is forced through a die to form lengths
     of rod, tube or special sections.

4-AAP Colorimetric - A standard method of measurement for phenols
     in aqueous solutions.

Fermentation - A chemical change to break down biodegradable waste.
     The change is induced by a living organism or enzyme, specific-
     ally bacteria or microorganisms occurring in unicellular plants
     such as yeast, molds, or fungi.

Ferrite - A solid solution in which alpha iron is present.

Ferrous - Relating to or containing iron.

Filtrate - Liquid after passing through a filter.

Filtration - Removal of solid particles from liquid or particles
     from air or gas stream by means of a permeable membrane.
     Types:  Gravity, Pressure, Microstraining, Ultrafiltration,
     Reverse Osmosis (Hyperfiltration).
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Flameless Atomic Absorption - A method of measuring low concen-
     tration values of certain metals in a solution.

Flame Hardened - Surface hardened by controlled torch heating
     followed by quenching with water or air.

Flame Spraying - The process of applying a metallic coating to a
     workpiece whereby finely powdered fragments or wire, together
     with suitable fluxes, are projected through a cone of flame
     onto the workpiece.

Flash Evaporation - Evaporation using steam heated tubes with feed
     material under high vacuum.  Feed material "flashes off" when
     it enters the evaporation chamber.

Flocculation - The process of separating suspended solids from waste-
     water by chemical creation of clumps or floes.

Flotation - The process of removing finely divided particles from
     a liquid suspension by attaching gas bubbles to the particles,
     increasing their buoyancy, and thus concentrating them at the
     surface of the liquid medium.

Fluxing - (Degassing)  The removal of oxides and other impurities
     from molten primary aluminum in a casthouse holding furnace by
     injecting chlorine gas (often with nitrogen and carbon monoxide).

Fog - A type of rinse consisting of a fine spray.

Forming Compounds (Sheet) - Tightly adhering lubricants composed of
     fatty oils, fatty acids, soaps, and waxes and designed to resist
     the high surface temperatures and pressures the metal would
     otherwise experience in forming.

Forming Compounds (Wire) - Tightly adhering lubricants composed of
     solids (white lead, talc, graphite, or molybdenum disulfide)
     and solible oils for cooling and corrosion protection.  Lubri-
     cants typically contain sulfur, chlorine, or phsophate additives.

Free Cyanide - 1.  True - the actual concentration of cyanide radical
     or equivalent alkali cyanide not combined in complex ions with
     metals in solutions.  2.  Calculated - the concentration of
     cyanide or alkali cyanide present in solution in excess of that
     calculated as necessary to form a specified complex ion with a
     metal or metals present in solution.  3.  Analytical - the free
     cyanide content of a solution as determined by a specified
     analytical method.

Freezing/Crystallization - The solidification of a liquid into
     aggregations of regular geometric forms (crystals) accomplished
     by subtraction of heat from the liquid.  This process can be used
     for removal of solids, oils, greases, and heavy metals from
     industrial wastewater.
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Galvanizing - The deposition of  zinc on  the  surface of  steel  for
     corrosion protection.

Gas Carburizing - The  introduction of carbon  into  the surface  layers
     of mill steel by  heating  in a current of gas  high  in  carbon.

Gas Chromotagrophy - Chemical  analytical  instrumentation generally
     used for quantitative organic analysis.

Gas Nitriding - Case hardening metal by  heating and diffusing  nitro-
     gen gas into the  surface.

Gas Phase Separation - The process of separating volatile  constitu-
     ents from water by the application  of selective gas permeable
     membranes.

Gear Forming - Process for making small  gears by rolling the gear
     material as it is pressed between hardened gear shaped dies.

Glass Fiber Filtration - A standard method of measuring total  sus-
     pended solids.

Good Housekeeping - (In-Plant  Technology)  Good and proper mainten-
     ance minimizing spills and  upsets.

GPP - Gallons per day-

Grab Sample - A single sample  of wastewater taken without regard
     to time or flow.

Gravimetric 103-105C - A standard method of measuring total
     solids in aqueous solutions.

Gravimetric 550C - A standard  method of measuring total volatile
     solids in aqueous solutions.

Gravity Filtration - Settling  of heavier and rising of lighter
     constituents within a solution.

Gravity Flotation - The separation of water and low density contam-
     inants such as oil or grease by reduction of the wastewater
     flow velocity and turbulence for a sufficient time to permit
     separation due to difference in specific gravity.  The floated
     material is removed by some skimming technique.

Gray Cast Irons - Alloys primarily of iron, carbon and silicon along
     with other alloying elements in which the graphite is in  flake
     form.  (These irons are characterized by low ductility but have
     many other properties such as good castability and good damping
     capacity.)
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Grease - In wastewater, a group of substances including  fats, waxes,
     free fatty acids, calcium and magnesium soaps, mineral  oils,
     and certain other nonfatty materials.  The type of  solvent
     and method used for extraction should be stated for quantifi-
     cation.

Grease Skimmer - A device for removing floating grease or  scum from
     the surface of wastewater in a tank.

Grinding - The removal of stock from a workpiece by use  of abrasive
     grains held by a rigid or semi rigid binder.  1.  Surface
     Grinding - Producing a flat surface with a rotating grinding
     wheel as the workpiece passes under the wheel.  2.  Cylindrical
     Grinding - Grinding the outside diameters of cylindrical work-
     pieces held between centers.  3.  Internal Grinding - Grinding
     the inside of a rotating workpiece by use of a wheel  spindle
     which rotates and reciprocates through the length of  depth of
     the hole being ground.

Grinding Fluids - Water based, straight oil, or synthetic  based
     lubricants containing mineral oils, soaps, or fatty materials
     lubricants serve to cool the part and maintain the  abrasiveness
     of the grinding wheel face.

Hammer Forging - Heating and pounding metal to shape it  into the
     desired form.

Hardened - Designates condition produced by various heat treatments
     such as quench hardening, age hardening and precipitation
     hardening.

Hardness - A characteristic of water, imparted by salts of calcium,
     magnesium and iron such as bicarbonates, carbonates,  sulfates,
     chlorides and nitrates, that cause curdling of soap,  deposition
     of scale, damage in some industrial processes and sometimes
     objectionable taste-  It may be dtermined by a standard labora-
     tory procedure or computed from the amounts of calcium  and
     magnesium as well as iron, aluminum, manganese, barium,
     strontium, and zinc and is expressed as equivalent  calcium
     carbonate.

Heading - (Material forming)  Upsetting wire, rod or bar stock in
     dies to form parts having some of the cross-sectional area
     larger than the original.  Examples are bolts, rivets and
     screws.

Heat Resistant Steels - Steel with high resistance to oxidation and
     moderate strength at high temperatures above 500 Degrees C.
                            XV-2 2

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Heat Treatment - The modification  of  the  physical  properties  of a
     workpiece through  the  application  of controlled  heating  and
     cooling cycles.  Such  operations are heat  treating,  tempering,
     carburizing, cyaniding,  nitriding, annealing,  normalizing,
     austenizing, quenching,  austempering,  siliconizing,  martemper-
     ing, and malleabilizing  are included in  this  definition.

Heavy Metals - Metals which can be precipitated  by hydrogen sulfide
     in acid solution,  e.g.,  lead, silver,  gold, mercury,  bismuth,
     copper, nickel, iron,  chromium,  zinc,  cadmium, and  tin.

High Energy Forming - Processes where parts are  formed at  a rapid
     rate by using extremely  high  pressures.  Examples:   Explosive
     forming, Electrohydraulic forming.

High Energy Rate Forging  (HERF) -  A closed  die process where  hot or
     cold deforming is  accomplished by  a  high velocity ram.

Robbing - Gear cutting  by use of a tool resembling  a  worm  gear  in
     appearance, having helically-spaced  cutting teeth.   In a single-
     thread hob, the rows of  teeth advance  exactly  one pitch  as  the
     hob makes one revolution.  With  only one hob,  it is possible to
     cut interchangeable gears of  a given pitch  of  any number of
     teeth within the range of the hobbing  machine.

Honing - A finishing operation using  fine grit abrasive  stones  to
     produce accurate dimensions and  excellent finish.

Hot Compression Molding -  (Plastic Processing)   A  technique of
     thermoset molding  in which preheated molding  compound is closed
     and heat and pressure  (in the form of  a downward moving  ram)
     are applied until  the  material has cured.

Hot Dip Coating - The process of coating  a  metallic workpiece with
     another metal by immersion in a molten bath to provide a pro-
     tective film.

Hot Rolled - A term used to describe  alloys which  are rolled  at  tem-
     peratures above the recrystallization  temperature.   (Many  alloys
     are hot rolled, and machinability of such alloys may  vary  because
     of differences in  cooling conditions from lot  to lot.

Hot Stamping - Engraving operation for marking plastics  in which roll
     leaf is stamped with heated metal dies onto the  face  of  the
     plastics.  Ink compounds can  also be used.

Hot Upset Forging - The diameter is locally increased i.e. to upset
     the head of a bolt, the  end of the barstock is heated and  then
     deformed by an axial blow often  into a suitably  shaped die.

Hydrofluoric Acid - Hydrogen  fluoride in  aqueous solution.
                              XV-23

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Hydrogen Embrittlement - Embrittlement of a metal or alloy caused by
     absorption of hydrogen during a pickling, cleaning, or plating
     process.

Hydrometallurgical Process - The treatment of ores by wet processes
     such as leaching.

Hydrophilic - A surface having a strong affinity for water or being
     readily wettable.

Hydrophobic - A surface which is non-wettable or not readily wettable.

Hydrostatic Pressure - The force per unit area measured in terms of
     the height of a column of water under the influence of gravity.

Immersed Area - Total area wetted by the solution or plated area plus
     masked area.

Immersion Plate - A metallic deposit produced by a displacement re-
     action in which one metal displaces another from solution, for
     example:   Fe + Cu(+2) = Cu + Fe(+2)

Impact Deformation - The process of applying impact force to a work-
     piece such that the workpiece is permanently deformed or shaped.
     Impact deformation operations such as shot peening, peening,
     forging, high energy forming, heading, or stamping.

Incineration - (Sludge Disposal)  The combustion (by burning) of
     organic matter in wastewater sludge after dewatering by
     evaporation.

Incompatible Pollutants - Those pollutants which would cause harm to,
     adversely affect the performance of, or be inadequately treated
     in publicly-owned treatment works.

Independent Operation - Job shop or contract shop in which electro-
     plating is done on workpieces owned by the customer.

Indirect Labor Costs - Labor-related costs paid by the employer
     other than salaries, wages and other direct compensation such as
     social security and insurance.

Induction Hardened - Surface or through hardened using induction
     heating followed by quenching with water or air.

Industrial User - Any industry that introduces pollutants into public
     sewer systems and whose wastes are treated by a publicly-owned
     treatment facility.

Industrial Wastes - The liquid wastes from industrial processes, as
     distinct from domestic or sanitary wastes.
                               XV-2 4

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Inhibition - The slowing down or stoppage of chemical or biological
     reactions by certain compounds or ions.

In-Process Control Technology - The regulation and the conservation
     of chemicals and the reduction of water usage throughout the
     operations as opposed to end-of-pipe treatment.

Inspection - A checking or testing of something against standards or
     specification.

Intake Water - Gross water minus reuse water.

Integrated Chemical Treatment - A waste treatment method in which a
     chemical rinse tank is inserted in the plating line between the
     process tank and the water rinse tank.  The chemical rinse
     solution is continuously circulated through the tank and removes
     the dragout while reacting chemicals with it.

Integrated Circuit (1C) - 1.  A combination of interconnected circuit
     elements inseparably associated on or within a continuous sub-
     strate.  2.  Any electronic device in which both active and
     passive elements are contained in a single package.  Methods of
     making an integrated circuit are by masking process, screening
     and chemical deposition.

Intraforming - A method of forming by means of squeezing.

Investment Costs - The capital expenditures required to bring the
     treatment or control technology into operation.

Ion Exchange - A reversible chemical reaction between a solid (ion
     exchanger) and a fluid (usually a water solution)  by means of
     which ions may be interchanged from one substance to another.
     The superficial physical structure of the solid is not
     affected.

Ion Exchange Resins - Synthetic resins containing active groups
     (usually sulfonic, carboxylic, phenol, or substituted amino
     groups) that give the resin the property of combining with
     or exchanging ions between the resin and a solution.

Ion-Flotation Technique - Treatment for electroplating rinse waters
     (containing chromium and cyanide) in which ions are separated
     from solutions by flotation.

Iridite Dip Process - Dipping process for zinc or zinc-coated objects
     that deposits protective film that is a chromium gel, chromium
     oxide, or hydrated chromium oxide.

Isolation - Segregation of a waste for separate treatment and/or
     disposal.
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Kiln - (Rotary)  A large cylindrical mechanized type of furnace.

Kinematic Viscosity - The viscosity of a fluid divided by its density.
     The C.G.So unit is the stoke (cm2/sec).

Knurling - Impressing a design into a metallic surface, usually by
     means of small, hard rollers that carry the corresponding design
     on their surfaces,

Lagoon - A man-made pond or lake for holding wastewater for the removal
     of suspended solids.  Lagoons are also used as retention ponds,
     after chemical clarification to polish the effluent and to safe-
     guard against upsets in the clarifier; for stabilization of
     organic matter by biological oxidation; for storage of sludge;
     and for cooling of water.

Laminate - 1.  A composite metal, wood or plastic usually in the form
     of sheet or bar, composed of two or more layers so bonded that
     the composite forms a structural member.  2.  To form a product
     of two or more bonded layers.

Landfill - Disposal of inert, insoluble waste solids by dumping at an
     approved site and covering with earth.

Lapping - An abrading process to improve surface quality by reducing
     roughness, waviness and defects to produce accurate as well as
     smooth surfaces.

Laser Beam Machining - Use of a highly focused mono-frequency colli-
     mated beam of light to melt or sublime material at the point of
     impingement on a workpiece.

Leach Field - A area of ground to which wastewater is discharged.
     Not considered an acceptable treatment method for industrial
     wastes.

Leaching - Dissolving out by the action of a percolating liquid,
     such as water, seeping through a landfill.

Ligands - The molecules attached to the central atom by coordinate
     covalent bonds.

Liquid/Liquid Extraction - A process of extracting or removing contam-
     inant(s) from a liquid by mixing contaminated liquid with another
     liquid which is immiscible and which has a higher affinity for
     the contaminating substance(s) .

Liquid Nitriding - Process of case hardening a metal in a molten
     cyanide bath.
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Liquid Phase Refining  - A metal with  an  impurity possessing  a  lower
     melting point  is  refined  by heating  the metal  to  the  point  of
     melting of the  low temperature metal.  It  is separated  by sweat-
     ing out.

Machining - The process of removing stock from  a workpiece by  forcing
     a cutting tool  through  the workpiece removing  a chip  of basis
     material.  Machining operations  such as turning,,  milling, drill-
     ing, boring, tapping, planing, broaching,  sawing  and  filing, and
     chamfering are  included in this  definition.

Maintenance - The upkeep of  property  or  equipment.

Malleablizing - Process of annealing  brittle white  cast  iron in  such
     a way that the  combined carbon is wholly or partly  transformed
     to graphitic or temper  carbon nodules  in a ferritic or  pearlitic
     microstructure, thus providing a ductile and machinable material.

Manual Plating - Plating in  which the workpieces are conveyed  manually
     through successive cleaning and  plating tanks.

Maraged - Describes  a  series of heat  treatments used to  treat  high
     strength steels of complex composition (maraging  steels)  by
     aging of martensite.

Martensite - An acicular or  needlelike microstructure  that is  formed
     in quenched steels.  (It  is very hard  and  brittle in  the  quenched
     form and, therefore, is usually  tempered before being placed into
     service.  The harder forms of tempered martensite have  poorer
     machinability-)

Martempering - Quenching an  austentized  ferrous alloy  in a medium at a
     temperature in  the upper  part of the martensite range,  or slight-
     ly above that range, and  holding it  in the medium until the
     temperature throughout  the alloy is  substantially uniform.
     The alloy is then allowed to cool in  air through  the  martensite
     range.

Masking - The application of a substance  to a surface  for  the  pre-
     vention of plating to said area.

Material Modification  - (In-Plant Technology)  Altering  the  substance
     from which a part is made.

Mechanical Agitation - The agitation  of  a  liquid medium  through  the
     use of mechanical equipment such as  impellers  or paddles.

Mechanical Finish - Final operations  on  a product performed  by a
     machine or tool.  See:  Polishing,  Buffing, Barrel  Finishing,
     Shot Peening, Power Brush Finishing.
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Mechanical Plating - Providing a coating wherein  fine metal  powders
     are peened onto the part by tumbling or other means.

Membrane - A thin sheet of synthetic polymer through the apertures
     of which small molecules can pass, while  larger ones  are  re-
     tained.

Membrane Filtration - Filtration at pressures  ranging from 50  to 100
     psig with the use of membranes or thin films.  The membranes
     have accurately controlled pore sites and  typically low flux
     rates.

Metal Ion - An atom or radical that has lost or gained one or  more
     electrons and has thus acquired an electric  charge.   Positively
     charged ions are cations, and those having a negative charge
     are anions.  An ion often has entirely differnt properties from
     the element (atom) from which it was formed.

Metal Oxidation Refining - A refining technique that removes impuri-
     ties from the base metal because the impurity oxidizes  more
     readily than the base.  The metal is heated  and oxygen  supplied.
     The impurity upon oxidizing separates by  gravity or volatilizes.

Metal Paste Production - Manufacture of metal  pastes for use as pig-
     ments by mixing metal powders with mineral spirits, fatty acids
     and solvents.  Grinding and filtration are steps in the process.

Metal Powder Production - Production of metal  particles for  such uses
     as pigments either by milling and grinding of scrap or  by atomi-
     zation of molten metal.

Metal Spraying - Coating metal objects by spraying molten  metal upon
     the surface with gas pressure.

Microstraining - A process for removing solids  from water,  which con-
     sists of passing the water stream through  a  microscreen with
     the solids being retained on the screen.

Milling - Using a rotary tool with one or more  teeth which engage the
     workpiece and remove material as the workpiece moves  past the
     rotating cutter.  1.  Face Milling - Milling a surface  perpendi-
     cular cutting edges remove the bulk of the material while the
     face cutting edges provide the finish of  the surface  being
     generated.  2.   End Milling - Milling accomplished with a tool
     having cutting edges on its cylindrical sufaces as well as on
     its end.  In end milling - peripheral, the peripheral cutting
     edges on the cylindrical surface are used; while in end milling-
     slotting,  both end and peripheral cutting  edges remove  metal.
     3.   Slide and Slot Milling - Milling of the  side or slot  of a
     workpiece using a peripheral cutter.  4.   Slab Milling  -  Milling
     of a surface parallel to the axis of a helical, multiple-toothed
     cutter mounted on an arbor.  5.  Straddle  Milling - Peripheral
     milling a workpiece on both sides at once  using two cutters
     spaced as required.
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Molecule - Chemical units composed of one or more atoms.

Monitoring - The measurement, sometimes continuous, of water quality.

Multi-Effect Evaporator - A series of evaporations and condensations
     with the individual units set up in series and the latent heat of
     vaporization from one unit used to supply energy for  the next.

Multiple Operation Machinery - Two or more  tools are used  to perform
     simultaneous or consecutive operations.

Multiple Subcategory Plant - A plant discharging process wastewater
     from more than one manufacturing process subcategory.

National Pollutant Discharge Elimination System (NPDES) -  The federal
     mechanism for regulating point source  discharge by means of
     permits.

Navigable Waters - All navigable waters of  the United States; tribu-
     taries of navigable waters of the United States; interstate
     waters,intrastate lakes, rivers and streams which are utilized
     for recreational or other purposes.

Neutralization - Chemical addition of either acid or base  to a solu-
     tion such as the pH is adjusted to 7.

New Source - Any building, structure, facility, or installation from
     which there is or may be the discharge of pollutants, the con-
     struction of which is commenced after  the publication of proposed
     regulations prescribing a standard of  performance under Section
     306 of the Act which will be applicable to such source if such
     standard is thereafter promulgated in  accordance with Section
     306 of the Act.

Nitriding - A heat treating method in which nitrogen is diffused  into
     the surface of iron-base alloys.  (This is done by heating the
     metal at a temperature of about 950 degrees F in contact with
     ammonia gas or other suitable nitrogenous materials.  The surface,
     because of formation of nitrides becomes much harder  than the
     interior.  Depth of the nitrided surface is a function of the
     length of time of exposure and can vary from .0005" to .032"
     thick.  Hardness is generally in the 65 to 70 Re range, and,
     therefore, these structures are almost always ground.)

Nitriding Steels - Steels which are selected because they  form good
     case hardened structures in the nitriding process.  ( In these
     steels, elements such as aluminum and  chromium are important
     for producing a good case.)

Nitrification (Biological) - The oxidation  of nitrogenous  matter  into
     nitrates by bacteria.
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Noble Metals - Metals below hydrogen in the electromotive  force  series;
     includes antimony, copper, rhodium, silver, gold, bismuth.

Noncontact Cooling Water - Water used for cooling which does not  come
     into direct contact with any raw material, intermediate product,
     waste product, or finished product.

Nonferrous - No iron content.

Non-Water Quality Environmental Impact - The ecological impact as  a
     result of solid, air, or thermal pollution due to the appli-
     cation of various wastewater technologies to achieve  the effluent
     guidelines limitations.  Associated with the non-water quality
     aspect is the energy impact of wastewater treatment.

Normalizing - Heat treatment of iron-base alloys above the critical
     temperature, followed by cooling in still air.   (This is often
     done to refine or homogenize the grain structure of castings,
     forgings and wrought steel products.)

Notching - Cutting out various shapes from the edge or side of a
     sheet, strip, blank or part.

NPDES - See National Pollutant Discharge Elimination System.

Oil Cooker - Open-topped vessel contining a heat source and typically
     maintained at 68°C (180°F) for the purpose of driving off excess
     water from waste oil.

Operation and Maintenance Costs - The cost of running the wastewater
     treatment equipment.  This includes labor costs, material and
     supply costs, and energy and power costs.

Organic Compound - Any substance that contains the element carbon,
     with the exception of carbon dioxide and various carbonates.

ORP Recorders - Oxidation-reduction potential recorders.

Oxidants - Those substances which aid in the formation of oxides.

Oxidizable Cyanide - Cyanide amenable to oxidation.

Oxidizing - Combining the material concerned with oxygen.

Paint Stripping - The term "paint stripping" shall mean the process
     of removing an organic coating from a workpiece or painting
     fixture.   The removal of such coatings using processes such
     as caustic, acid, solvent and molten salt stripping are included.
                                  XV-30

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 Parameter - A characteristic element of constant factor.

 Passivation - The changing of the chemically active surface of a
      metal to a much less reactive state by means of an acid dip.

 Patina - A blue green oxidation of copper.

 Pearlite - A microstituent found in iron-base alloys consisting of
      a lamellar (Patelike) composite of ferrite and iron carbide.
      (This structure results from the decomposition of austenite
      and is very common in cast irons and annealed steels.)

 Peening  - Mechanical working of metal by hammer blows or shot im-
      pingement.

 p_H  -  A unit for measuring hydrogen ion concentrations.  A pH of 7
      indicates  a "neutral" water or solution.  A pH lower than 7,
      a solution is  acidic.  At  pH higher than 1, a solution is
      alkaline.

 pH  Buffer - A substance used to stabilize the acidity or alkalinity
      in  a solution.

 Phenols  - A group of aromatic compounds having  the hydroxyl group
      directly attached  to the benzene ring.   Phenols can be a con-
      taminant in a  waste stream from a manufacturing process.

 Phosphate Coating - Process of  forming a conversion coating on iron
      or  steel by immersing in a hot solution  of manganese,  iron or
      zinc phosphate.  Often used on a metal part prior to  painting
      or  porcelainizing.

 Phosphate - Salts or  esters of  phosphoric  acid.

 Phosphatizing -  Process  of forming  rust-resistant  coating  on iron
      or  steel by immersing in a hot solution  of acid manganese,
      iron or  zinc phosphates.

 Photoresists  - Thin  coatings  produced  from organic  solutions
      which  when  exposed  to light  of the  proper  wave  length  are
      chemically  changed  in their  solubility to  certain  solvents
      (developers).  This  substance  is  placed  over  a  surface which
      is  to  be protected  during  processing  such  as  in  the etching
      of printer  circuit  boards.

Photosensitive Coating - A chemical  layer  that  is  receptive to
      the  action  of radiant energy.
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Pickling  - The immersion of all or part of a workpiece  in a
     corrosive media such as acid to remove scale and related
     surface coatings.

Planing - Producing flat surfaces by linear reciprocal motion of
     the work and the table to which it is attached relative to
     a stationary single-point cutting tool.

Plant Effluent or Discharge After Treatment - The wastewater
     discharged from the industrial plant.  In this definition,
     any waste treatment device (pond, trickling filter, etc.)
     is considered part of the industrial plant.

Plasma Arc Machining - The term "plasma arc machining" shall mean
     the process of material removal or shaping of a workpiece
     by a high velocity jet of high temperature ionized gas.

Plated Area - Surface upon which an adherent layer of metal is
     deposited.

Plating - Forming an adherent layer of metal upon an object.

Point Source - Any discernible, confined, and discrete conveyance
     including, but not limited to, any pipe, ditch, channel,
     tunnel, conduit, well, discrete fissure, container, rolling
     stock, concentrated animal feeding operation, or vessel or
     other floating craft from which pollutants are or may be
     discharged.

Point Source Category - See Category.

Polishing - The process of removing stock from a workpiece by the
     action of loose or loosely held abrasive grains carried to
     the workpiece by a flexible support.  Usually, the amount of
     stock removed in a polishing operation is only incidental to
     achieving a desired surface finish or appearance.

Polishing Compounds - Fluid or grease stick lubricants composed
     of animal tallows, fatty acids, and waxes.  Selection depends
     on surface finish desired.

Pollutant - Dredged spoil,  solid waste, incinerator residue, sewage,
     garbage, sewage sludge, munitions, chemical wastes, biological
     materials, radioactive materials, heat, wrecked or discarded
     equipment, rock, sand, cellar dirt and industrial, municipal
     and agricultural waste discharged into water.  It does not
     mean (1) sewage from vessels or (2) water, gas, or other mat-
     erial which is injected into a well to facilitate production
     of oil or gas, or water derived in association with oil or
     gas production and disposed of in a well, if the well, used
     either to facilitate production or for disposal purposes, is
                               XV-32

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     approved by authority of the State in which the well is
     located, and if such State determines that such injection
     or disposal will not result in degradation of ground or
     surface water resources.

Pollutant Parameters - Those constituents of wastewater deter-
     minded to be detrimental and, therefore, requiring control.

Pollution - The man-made or man-induced alternation of the
     chemical, physical, biological, and radiological integrity
     of water.

Polychlorinated Biphenyl (PCB) - A family of chlorinated biphenyls
     with unique thermal properties and chemical inertness which
     have a wide variety of uses as plasticizers, flame retardants
     and insulating fluids.  They represent a persistent contam-
     inant in waste streams and receiving waters.

Polyelectrolyte - A high polymer substance, either natural or
     synthetic, containing ionic constituents; they may be either
     cationic or anionic.

Post Curring - Treatment after changing the physical properties
     of a material by chemical reaction.

Pouring - (Casting and Molding)  Transferring molten metal from
     a furnace or a ladle to a mold.

Power Brush Finishing - This is accomplished (wet or dry) using a
     wire or nonmetallic-fiber-filled brush used for deburring,
     edge blending and surface finishing of metals.

Precious Metals - Gold, silver, iridium, palladium, platinum,
     rhodium, ruthenium, indium, osmium, or combination thereof.

Precipitate - The discrete particles of material rejected from  a
     liquid solution.

Precipitation Hardening Metals - Certain metal compositions which
     respond to precipitation hardening or aging treatment.

Pressure Deformation - The process of applying force, (other  than
     impact force), to permanently deform or shape a workpiece.
     Pressure deformation operations may include operations such
     as rolling, drawing, bending, embossing, coining, swaging,
     sizing, extruding, squeezing, spinning, seaming, piercing,
     necking, reducing, forming, crimping, coiling, twisting,
     winding, flaring or weaving.

Pressure Filtration - The process of solid/liquid phase separation
     effected by passing the more permeable liquid phase through a
     mesh which is impenetrable to the solid phase.
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Pretreatment - Treatment of wastewaters from sources before  intro-
     duction into municipal treatment works.

Primary Settling - The first treatment for the removal of settle-
     able solids from wastewater which is passed through a treat-
     ment works.

Primary Treatment - The first stage in wastewater treatment  in
     which floating or settleable solids are mechanically removed
     by screening and sedimentation.

Printed Circuit Boards - A circuit in which the interconnecting
     wires have been replaced by conductive strips printed,  etched,
     etc., onto an insulating board.  Methods of fabrication in-
     clude etched circuit, electroplating, and stamping.

Printing - A process whereby a design or pattern in ink or types
     of pigments are impressed onto the surface of a part.

Process Modification - (In-Plant Technology)  Reduction of water
     pollution by basic changes in a manufacturing process.

Process Wastewater - Any water which, during manufacturing or
     processing, comes into direct contact with or results from
     the production or use of any raw material, intermediate
     product, finished product, byproduct, or waste product.

Process Water - Water prior to its direct contact use in a process
     or operation.  (This water may be any combination of raw water,
     service water, or either process wastewater or treatment facil-
     ity effluent to be recycled or reused).

Punching - A method of cold extruding, cold heading, hot forging or
     stamping in a machine whereby the mating die sections control
     the shape or contour of the part.

Pyrolysis -  (Sludge Removal)  Decomposition of materials by  the
     application of heat in any oxygen-deficient atmosphere.

Pyrazolone-Colorimetric - A standard method of measuring cyanides
     in aqueous solutions.

Quantity GPP - Gallons per day.

Quenching - Rapid cooling of alloys by immersion in water, oil, or
     gases after heating.

Racking - The placement of parts on an apparatus.for the purpose
     of plating.

Rack Plating - Electroplating of workpieces on racks.
                             KV-34

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Radiography  - A nondestructive  method  of  internal  examination
      in which metal  or  other  objects are  exposed to  a  beam  of
      x-ray or gamma  radiation.   Differences  in  thickness, density
      or absorption,  caused  by internal discontinuities,  are
      apparent in  the shadow image  either  on  a fluorescent screen
      or on photographic film  placed behind the  object.

Raw Water -  Plant intake water  prior to any  treatment  or use.

Reaming - An operation  in which a  previously formed  hole is sized
      and contoured accurately by using a  rotary cutting  tool  (reamer)
      with one or  more cutting elements (teeth).  The principal  sup-
      port for the reamer during the cutting  action is  obtained  from
      the workpiece.   1.  Form Reaming  - Reaming to a contour shape.
      2.  Taper Reaming  - Using  a special  reamer for  taper pins.  3.
      Hand Reaming -  Using a long lead  reamer which permits  reaming
      by hand.  4.  Pressure Coolant Reaming  (or Gun  Reaming) -
      Using a multiple-lip,  end  cutting tool  through  which coolant  is
      forced  at high  pressure  to flush  chips  ahead  of the tool or
      back through the flutes  for finishing of deep holes.

Receiving Waters  - Rivers,  lakes,  oceans, or other water courses
      that receive treated or  untreated wastewaters.

Recirculating Spray  - A spray rinse in which the drainage is pumped
      up to the spray and is continually recirculated.

Recycled Water -  Process wastewater or treatment facility effluent
      which is recirculated  to the  same process.

Recycle Lagoon -  A pond that  collects  treated wastewater, most  of
      which is recycled  as process  water.

Reduction - A reaction  in which there  is  a decrease  in valence
      resulting from  a gain  in electrons.

Redox - A term used  to  abbreviate  a reduction-oxidation  reaction.

Residual Chlorine -  The  amount  of  chlorine left in the treated
     water that is available  to oxidize contaminants.

Reverse Osmosis - The application  of pressure to the surface of
     solution through a semipermeable  membrane  that  is too  dense
     to permit passage  of the solute,  leaving behind the dissolved
     solids  (concentrate).

Reused Water - Process  wastewater  or treatment  facility  effluent
     which is further used  in a different manufacturing  process.

Ring Rolling - A  metals process  in which  a doughnut  shaped  piece of
     stock is flattened to  the  desired ring  shape  by rolling between
     variably spaced rollers.   This process  produces a seamless ring.
                              XV-35

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Rinse - Water for removal of dragout by dipping,  spraying,
     fogging, etc.

Riveting - Joining of two or more members of a structure  by  means
     of metal rivets, the undeaded end being upset after  the rivet
     is in place.

Routing - Cutting out and contouring edges of various  shapes in  a
     relatively thin material using a small diameter rotating
     cutter which is operated at fairly high speeds.

Running Rinse - A rinse tank in which water continually flows  in
     and out.

Rust Prevention Compounds - Coatings used to protect iron and  steel
     surfaces, against corrosive environment during fabrication,
     storage, or use.

Salt -  1.  The compound formed when the hydrogen of an acid is
     replaced by a metal or its equivalent (e.g., an NH4 radical).
     Example:     HC1 + NaOH = NaCl + H20
     This is typical of the general rule that the reaction of  an
     acid and a base yields a salt and water.  Most salts ionize
     in water solution.  2.  Common salt, sodium  chloride, occurs
     widely in nature, both as deposits left by ancient seas and
     in the ocean, where its average concentration is  about  3%.

Salt Bath Descaling - Removing the layer of oxides formed on some
     metals at elevated temperatures in a salt solution.  See:
     Reducing, Oxidizing, Electrolytic.

Sand Bed Drying - The process of reducing the water content  in a wet
     substance by transferring that substance to  the surface of  a
     sand bed and allowing the processes of drainage through the
     sand and evaporation to effect the required water separation.

Sand Blasting - The process of removing stock including surface
     films, from a workpiece by the use of abrasive grains
     pneumatically impinged against the workpiece.

Sand Filtration - A process of filtering wastewater through  sand.
     The wastewater is trickled over the bed of sand where air and
     bacteria decompose the wastes.  The clean water flows out
     through drains in the bottom of the bed.  The sludge accumulat-
     ing at the surface must be removed from the bed periodically.

Sanitary Water - The supply of water used for sewage transport and
     the continuation of such effluents to disposal.

Sanitary Sewer - Pipes and conveyances for sewage transport.

Save Rinse - See Dead Rinse-
                              XV-3 6

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Sawing - Using a toothed blade or disc to sever parts or cut
     contours.  1.  Circular Sawing - Using a circular saw fed
     into the work by motion of either the workpiece or the
     blade.  2.  Power Band Sawing - Using a long, multiple-
     tooth continuous band resulting in a uniform cutting
     action as the workpiece is fed into the saw.  Power Hack
     Sawing - Sawing in which a reciprocating saw blade is fed
     into the workpiece.

Scale - Oxide and metallic residues.

Screening - Selectively applying a resist material to a surface
     to be plated.

Secondary Settling - Effluent from some prior treatment process
     flows for the purpose of removing settleable solids.

Secondary Treatment - The second step in most sanitary waste
     treatment plants in which bacteria consume the organic
     portions of the waste.  This removal is accomplished by trick-
     ling filters, an activated sludge unit, or other processes.

Sedimentation - The process of subsidence and deposition of suspended
     matter carried by water, wastewater, or other liquids by
     gravity.  It is usually accomplished by reducing the velocity
     of the liquid below the point at which it can transport the
     suspended material.  Also called settling.

Sensitization - The process in which a substance other than the
     catalyst is present to facilitate the start of a catalytic
     reaction.

Sequestering Agent - An agent (usually a chemical compound) that
     "sequesters" or holds a substance in suspension.

Series Rinse - A series of tanks which can be individually heated
     or level controlled.

Service Water - Raw water which has been treated preparatory to
     its use in a process or operation; i.e., makeup water.

Settleable Solids - That matter in wastewater which will not stay
     in suspension during a preselected settling period, such  as one
     hour, but either settles to the bottom or floats to the top.

Settling Ponds - A large shallow body of water into which  indus-
     trial wastewaters are discharged.  Suspended solids settle
     from the wastewaters due to the large retention time  of water
     in the pond.
                               XV-3 7

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Shaping - Using single point tools fixed to a ram reciprocated  in
     a linear motion past the work.  1.  Form Shaping - Shaping
     with a tool ground to provide a specified shape.  2.  Contour
     Shaping - Shaping of an irregular surface, usually with  the
     aid of a tracing mechanism.  3.  Internal Shaping - Shaping
     of internal forms such as keyways and guides.

Shaving - 1.  As a finishing operation, the accurate removal  of a
     thin layer by drawing a cutter in straight line motion across
     the work surfaces.  2.  Trimming parts like stampings, forgings
     and tubes to remove uneven sheared edges or to improve accuracy,

Shearing - The process of severing or cutting of a workpiece  by
     forcing a sharp edge or opposed sharp edges into the workpiece
     by forcing a sharp edge or opposed sharp edges into the  work-
     piece stressing the material to the point of sheer failure and
     separation.

Shipping - Transporting.

Shot Peening - Dry abrasive cleaning of metal surfaces by impacting
     the surfaces with high velocity steel shot.

Shredding - (Cutting or Stock Removal)  Material cut, torn or broken
     up into small parts.

SIC - Standard Industrial Classification - Defines industries in
     accordance with the composition and structure of the economy
     and covers the entire field of economic activity.

Silica - (Si02^  Dioxide of silicon which occurs in crystalline form
     as quartz, cristohalite, tridymite.  Used in its pure form for
     high-grade refractories and high temperature insulators  and in
     impure form (i.e. sand) in silica bricks.

Siliconiz ing - Diffusing silicon into solid metal, usually steel,
     at an elevated temperature for the purposes of case hardening
     thereby providing a corrosion and wear-resistant surface.

Sintering - The process of forming a mechanical part from a
     powdered metal by bonding under pressure and heat but below
     the melting point of the basis metal.

Sizing  1.   Secondary forming or squeezing operations, required
     to square up, set down, flatten or otherwise correct surfaces,
     to produce specified dimensions and tolerances.  See restriking.
     2.  Some burnishing, broaching, drawing and shaving operations
     are also called sizing.  3.  A finishing operation for correct-
     ing ovality in tubing.  4.  Powder metal.  Final pressing of
     a sintered compact.
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Skimming - The process of  removing  floating  solid or  liquid wastes
     from a wastewater stream by means of a  special tank  and  skim-
     ming mechanism prior  to treatment of the water.

Slaking - The process of reacting lime with  water to  yield a
     hydrated product.

Sludge - Residue produced  in a waste  treatment process.

Sludge Dewatering - The removal of  water from sludge  by introducing
     the water sludge slurry into a centrifuge.  The  sludge is
     driven outward with the water  remaining near the center.  The
     water is withdrawn and the dewatered sludge is usually land-
     filled.

Slurry - A watery suspension of solid materials.

Snagging - Heavy stock removal of superfluous material from a work
     piece by using a portable or swing grinder mounted with  a
     coarse grain abrasive wheel.

Soldering - The process of joining  metals by flowing  a thin
     (capillary thickness) layer of nonferrous filler metal into
     the space between them.  Bonding results from the intimate
     contact produced by the dissolution of  a small amount of base
     metal in the molten filler metal, without fusion of  the  base
     metal.  The term soldering is  used where the temperature range
     falls below 425°C (800°F).

Solids - (Plant Waste)  Residue material that has been completely
     dewatered.

Solute - A dissolved substance.

Solution - Homogeneous mixture of two or more components  such as a
     liquid or a solid in  a liquid.

Solution Treated - (Metallurgical)  A process by which it is
     possible to dissolve  micro-constituents by taking certain
     alloys to an elevated temperature and then keeping them  in
     solution after quenching.  (Often a solution treatment is
     followed by a precipitation or aging treatment to improve
     the mechanical properties.  Most high temperature alloys which
     are solution treated  and aged  machine better in  the  solution
     treated state just before they are aged.)

Solvent - A liquid used to dissolve materials.  In dilute solutions
     the component present in large excess is called  the  solvent
     and the dissolved substance is called the solute.

Solvent Cleaning - Removal of oxides, soils, oils, fats,  waxes,
     greases, etc. by solvents.
                               XV-3 9

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Solvent Degreasing - The removal of oils and grease from a
     workpiece using organic solvents or solvent vapors.

Specific Conductance - The property of a solution which allows
     an electric current to flow when a potential difference  is
     applied.

Spectrophotometry - A method of analyzing a wastewater sample by
     means of the spectra emitted by its constituents under
     exposure to light.

Spray Rinse - A process which utilizes the expulsion of water
     through a nozzle as a means of rinsing.

Spinning - Shaping of seamless hollow cylindrical sheet metal parts
     by the combined forces of rotation and pressure.

Spotfacing - Using a rotary, hole piloted end facing tool to produce
     a flat surface normal to the axis of rotation of the tool on or
     slightly below the workpiece surface.

Sputtering - The process of covering a metallic or non-metallic
     workpiece with thin films of metal.  The surface to be coated
     is bombarded with positive ions in a gas discharge tube,
     which is evacuated to a low pressure.

Squeezing - The process of reducing the size of a piece of heated
     material so that it is smaller but more compressed than it
     was before.

Stainless Steels - Steels which have good or excellent corrosion
     resistance.  (One of the common grades contains 18% chromium
     and 8% nickel.   There are three broad classes of stainless
     steels - ferritic, austenitic, and martensitic.  These various
     classes are produced through the use of various alloying
     elements in differing quantities.

Staking - Fastening two parts together permanently by recessing
     one part within the other and then causing plastic flow at
     the joint.

Stamping - A general term covering almost all press operations.
     It includes blanking, shearing, hot or cold forming, drawing,
     bending and coining.

Stamping Compounds - See Forming Compounds (Sheet).

Standard of Performance - Any restrictions established by the Admin-
     istrator pursuant to Section 306 of the Act on quantities,
     rates and concentrations of chemical, physical, biological,
     and other constituents which are or may be discharged from
     new sources into navigable waters, the waters of the contiguous
     zone or the ocean.
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Stannous Salt - Tin based compound used in the acceleration process.
     Usually stannous chloride.

Utill Rinse - See Dead Rinse.

Storm Water Lake - Reservoir for storage of storm water runoff
     collected from plant site;  also, auxiliary source of process
     water.

Stress Relieved - The heat treatment used to relieve the internal
     stresses induced by forming or heat treating operations.
     (It consists of heating a part uniformly, followed by cooling
     slow enough so as not to reintroduce stresses.  To obtain low
     stress levels in steels and cast irons, temperatures as high
     as 1250 degrees F may be required.)

Strike - A thin coating of metal (usually less than 0.0001 inch in
     thickness) to be followed by other coatings.

Stripping - The removal of coatings from metal.

Subcategory or Subpart - A segment of a point source for which
     specific effluent limitations have been established.

Submerged Tube Evaporation - Evaporation of feed material using
     horizontal steam-heat tubes submerged in solution.  Vapors
     are driven off and condensed while concentrated solution is
     bled off.

Subtractive Circuitry - Circuitry produced by the selective etching
     of a previously deposited copper layer.

Substrates - Thin coatings ( as of hardened gelatin) which act as a
     support to facilitate the adhesion of a sensitive emulsion.

Surface Tension - A measure of the force opposing the spread of
     a thin film of liquid.

Surface Waters - Any visible stream or body of water.

Surfactants - Surface active chemicals which tend to lower the
     surface tension between liquids, such as between acid and
     water.

Surge - A sudden rise to an excessive value, such as flow, pressure,
     temperature.

Swaging - Forming a taper or a reduction on metal products such as
     rod and tubing by forging, squeezing or hammering.

Tank - A receptacle for holding transporting or  storing  liquids.
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Tapping - Producing internal threads with a cylindrical cutting
     tool having two or more peripheral cutting elements shaped
     to cut threads of the desired size and form.  By a combination
     of rotary and axial motion, the leading end of the tap  cuts
     the thread while the tap is supported mainly by the thread  it
     produces.

Tempering - Reheating a quench-hardened or normalized ferrous  alloy
     to a temperature below the transformation range then  cooling
     at any rate desired.

Testing - The application of thermal, electrical, or mechanical
     energy to determine the suitability or functionality  of a
     part, assembly or complete unit.

Thermal Cutting - The term "thermal cutting" shall mean the  process
     of cutting, slotting or piercing a workpiece using an
     oxy-acetylene oxygen lance or electric arc cutting tool.

Thermal Infusion - The process of applying a fused zinc, cadmium or
     other metal coating to a ferrous workpiece by imbueing  the
     surface of the workpiece with metal powder or dust in the
     presence of heat.

Thickener - A device or system wherein the solid contents  of slurries
     or suspensions are increased by gravity settling and  mechanical
     separation of the phases, or by flotation and mechanical  separ-
     ation of the phases.

Thickening -  (Sludge Dewatering)  Thickening or concentration  is the
     process of removing water from sludge after the initial separ-
     ation of the sludge from wastewater.  The basic objective of
     thickening is to reduce the volume of liquid sludge to  be
     handled in subsequent sludge disposal processes.

Threading - Producing external threads on a cylindrical surface.
     1.  Die Threading - A process for cutting external threads
     on cylindrical or tapered surfaces by the use of solid  or
     self-operning dies.  2.  Single-Point Threading - Turing
     threads on a lathe.  3.  Thread Grinding - See definition
     under grinding.  4.  Thread Milling - A method of cutting
     screw threads with a milling cutter.

Threshold Toxicity - Limit upon which a substance becomes  toxic  or
     poisonous to a particular organism.

Through Hole Plating - The plating of the inner surfaces of  holes  in
     a PC board.

Titration    1.  A method of measuring acidity of alkalinity.   2.  The
     determination of a constituent in a known volume of solution  by
     the measured addition of a solution of known strength for complet-
     ion of the reaction as signaled by observation of an  end  point.
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Total Chromium - The sum of chromium in all valences.

Total Cyanide - The total content of cyanide expressed as the
     radical CN-  or alkali cyanide whether present as simple or
     complex ions.  The sum of both the combined and free cyanide
     content of a plating solution.  In analytical terminology,
     total cyanide is the sum of cyanide amenable to oxidation
     by chlorine and that which is not according to standard
     analytical methods.

Total Dissolved Solids  (TDS) - The total amount of dissolved solid
     materials present  in an aqueous solution.

Total Metal - Sum of the metal content in both soluble and  insoluble
     form.

Total Organic Carbon (TOC) - TOC is a measure of the amount of
     carbon in a sample originating from organic matter only.  The
     test is run by burning the sample and measuring the CC^2
     produced.

Total Solids - The sum  of dissolved and undissolved constituents
     in water or wastewater, usually stated in milligrams per liter.

Total Suspended Solids  (TSS) - Solids found in wastewater or in the
     stream, which in most cases can be removed by filtration.  The
     origin of suspended matter may be man-made or of natural
     sources, such as silt from erosion.

Total Volatile Solids - Volatile residue present in wastewater.

Tool Steels - Steels used to make cutting tools and dies.   (Many of
     these steels have  considerable quantities of alloying  elements
     such as chromium,  carbon, tungsten, molybdenum and other
     elements.  These form hard carbides which provide good wearing
     qualities but at the same time decrease machinability.  Tool
     steels in the trade are classified for the most part by their
     applications, such as hot work die, cold work die, high speed,
     shock resisting, mold and special purpose steels.)

Toxic Pollutants - A pollutant or combination of pollutants including
     disease causing agents, which after discharge and upon exposure,
     ingestion, inhalation or assimilation into any organism either
     directly or indirectly cause death, disease, cancer, genetic
     mutations, physiological malfunctions (including malfunctions
     in such organisms  and their offspring.

Treatment Facility Effluent - Treated process wastewater.

Trepanning - Cutting with a boring tool so designed as to leave
     an unmachined core when the operation is completed.
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Trickling Filters - A filter consisting of an artificial bed of
coarse material, such as broken stone, clinkers, slate, salts, or
brush over which an effluent is distributed and applied in drops,
films, or spray from troughs, drippers, moving distributors, or
fixed nozzles and through which it trickles to the underdrains
giving opportunity for the formation of zoological slimes which
clarify and oxidize the effluent.

Tumbling - See Barrel Finishing.

Tubidimeter - An instrument for measurement of turbidity in which
     a standard suspension is usually used for reference.

Turbidity -  1.  A condition in water or wastewater caused by the
     presence of suspended matter resulting in the scattering and
     absorption of light rays.   2.  A measure of fine suspended
     matter in liquids.  3.  An analytical quantity usually report-
     ed in arbitrary turbidity units determined by measurements of
     light diffraction.

Turning - Generating cylindrical forms by removing metal with a
     single-point cutting tool moving parallel to the axis of
     rotation of the work.  1.   Single-Point Turning - Using a
     tool with one cutting edge.  2.  Face Turning - Turning a
     surface perpendicular to the axis of the workpiece.  3.
     Form Turning - Using a tool with a special shape.  4.
     Turning Cutoff - Severing the workpiece with a special
     lathe tool.  5.  Box Tool Turning - Turning the end of
     workpiece with one or more cutters mounted in a boxlike
     frame, primarily for finish cuts.

Ultrafiltration - A process using semipermeable polymeric membranes
     to separate molecular or colloidal materials dissolved or
     suspended in a liquid phase when the liquid is under pressure.

Ultrasonic Agitation - The agitation of a liquid medium through
     the use of ultrasonic waves.

Ultrasonic Cleaning - Immersion cleaning aided by ultrasonic waves
     which cause microagitation.

Ultrasonic Machining - Material removal by means of an ultrasonic-
     vibrating tool usually working in an abrasive slurry in close
     contact with a workpiece or having diamond or carbide cutting
     particles on its end.

Unit Operation - A single, discrete process as part of an overall
     sequence, e.g., precipitation, settling and filtration.

Vacuum Deposition - Condensation of thin metal coatings on the cool
     surface of work in a vacuum.
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Vacuum Evaporization - A method of coating articles by melting
     and vaporizing the coating material on an electrically
     heated conductor in a chamber from which air has been
     exhausted.  The process is only used to produce a decor-
     ative effect.  Gold, silver, copper and aluminum have been
     used.

Vacuum Filtration - A sludge dewatering process in which sludge
     passes over a drum with a filter medium, and a vacuum is
     applied to the inside of the drum compartments.  As the
     drum rotates, sludge accumulates on the filter surface,
     and the vacuum removes water.

Vacuum Metalizing - The process of coating a workpiece with
     metal by flash heating metal vapor in a high-vacuum
     chamber containing the workpiece.  The vapor condenses on
     all exposed surfaces.

Vapor Blasting - A method of roughing plastic surfaces in prepar-
     ation foe plating.

Vapor Degreasing - Removal of soil and grease by a boiling liquid
     solvent, the vapor being considerably heavier than air.  At
     least one constituent of the soil must be soluble in the
     solvent.

Vapor Plating - Deposition of a metal or compound upon a heated
     surface by reduction or decomposition of a volatile compound
     at a temperature below the melting points of either the
     deposit or the basis material.

Viscosity - The resistance offered by a real fluid to a shear
     stress.

Volatile Substances - Material that  is readily vaporizable at  a
     relatively low temperature.

Volumetric Method - A standard method of measuring settleable
     solids in an aqueous solution.

Waste Discharged - The amount (usually expressed as weight) of
     some residual substance which is suspended or dissolved
     in the plant effluent.

Wastewater Constituents - Those materials which are carried by
     or dissolved in a water stream  for disposal.
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Wastewater - Any water that has been released from the purpose
     for which it was intended to be used.

Water Balance - An accounting of all water entering and  leaving
     a unit process or operation in either a liquid or vapor
     form or via raw material, intermediate product, finished
     product, by-product, waste product, or via process  leass,
     so that the difference in flow between all entering and
     leaving streams is zero.  The water balance should  clearly
     identify and indicate the magnitude of each water flow and
     distinguish between process wastewater and non-contact cool-
     ing water.

Water Recirculation or Recycling - The volume of water already
     used for some purpose in the plant which is returned with or
     without treatment to be used again in the same or another
     process.

Water Use - The total volume of water applied to various uses  in
     the plant.  It is the sum of water recirculation and water
     withdrawal.

Water Withdrawal or Intake - The volume of fresh water removed
     from a surface or underground water source by plant facil-
     ities or obtained from some source external to the  plant.

Welding - The process of joining two or more pieces of material
     by applying heat, pressure or both, with or without filler
     material, to produce a localized union through fusion or
     recrystallization across the interface.

Wet Air Oxidation - (Sludge Disposal)  The process of oxidizing
     sludge in the liquid phase without mechanical dewatering.
     High-pressure high-temperature air is brought into  contact
     with the waste material in a pressurized reactor.   Oxidation
     occurs at 300 to 500 degrees F and from several hundred  to
     3,000 psig.

Wholesale Price Index - A measure of the fluctuation of  the
     wholesale price of goods and services with time.  The base
     period to which all wholesale prices are related  is 1967
      (index = 100).

Withdrawal Phase - Period for the withdrawal of a part of
     workpiece from an immersion tank.

"Vorkpiece - The item to be processed.

  "ought  - Condition of a material which has been worked  mechani-
     cally as  in forging, rolling, drawing, et.
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