PB-234 931
SOLID WASTE  MILLING AND DISPOSAL ON  LAND WITHOUT COVER

VOLUME  II,   DATA CONDENSATIONS
CITY OF MADISON,  WISCONSIN
PREPARED FOR

ENVIRONMENTAL  PROTECTION AGENCY


1974
                            DISTRIBUTED BY:
                            National Technical Information Service
                            U. S. DEPARTMENT  OF COMMERCE

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DlBLIO&KA^r
SHEET
EPA/530/SW62d.2 ^" ^O*4- ^
4. 1 , '• . - : -u"-; .
SOLID WASTE MILLING AND DISPOSAL ON LAND WITHOUT COVER
Volume II
7. Au-^r's)
9. Performing (.
12. Sponsoring
15. Supplement
John J. Reinhardt and Robert K. Ham
H^jni/.ation NJITIL and Address
City of Madison, Wisconsin
Orjjnj/ iMon Name and Address
U.S. Environmental Protection Agency
Office of Solid Waste Management Programs
Washington, D. C. 20460
5- Keport Date
1973
6.
8. Performing Or^ani/ati'n t
\V.
10. PrO}ect I ask, Sort. ( n,' '\
11. Contrat t /Grant No.
G06-EC-00004
13. '1 ype of Report & IVrio.i
Covered
Final 1966-1972
14.
ary Nines
16. Abstracts
        The  project began as a practical  demonstration to investigate  the concept of
   milling solid waste for landfill disposal  without applying daily  cover.   The project
   was intended to gather data on the operation and cost of milling  equipment, the use
   of milled solid waste in a landfill,  and the characteristics of milled solid waste--
   all from  a practical standpoint.  Eventually, however, project oersonnel  carried
   ou,t detailed investigating work on .both  milled and unprocessed solid waste.  To
   determine whether landfniing milled  solid waste lived up to the  approval given by
   European  landfill operators, it became necessary to design experiments involvino
   rats, flies, leachate, gas, trees, etc. in  hopes of quantifying such factors.
   Volume  II contains condensations of data gathered during the project and  has been
   arranged  in sub-reports intended for  the researcher who may wish  to review the
   data.           |
17. Key 'i'ords and Documen; Analysis. 17di Descriptors
   *Waste  disposal, Urban areas; Crushers,  Comminution, Grinding mills  •„
17b. 1 !, ntili, ,-. Ppc.M-1 ml,,I Terms


   *Solid waste disposal, Madison,"Wisconsin
17c. < OS \ I I  I-
                                  ""NATIONAL TECHNICAL
                                   INFORMATION SERVICE
                                    U S Department of Commerce
                                       Springfield VA 22151
18. \' .ulat" 1,:;, st alt :i.ent

   Release  to public
19. Security ( lass (This
   Report )
     lA'Cl 'VSSII- I I'll
20. Sri lit It V t 1 I s s ( i ll I •.
21. No. ot I'a
                                                                             L.-5C OMM-<;

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         SOLID WASTE MILLING AND DISPOSAL ON  LAND WITHOUT COVER
                    Volume  II: Data Condensations
              This final report  (SW-62d.2)  an work performed
under Federal solid waste management demonstration grant No.  G06-EC-00004
             to the City of Madison, Wisconsin,  was written
                 by JOHN J. REINHARDT and ROBERT K. HAM
             and is reproduced as received  from  the grantee
                U.S.  ENVIRONMENTAL  PROTECTION AGENCY

                                 1974
                                          U.S. Environmental  Protection Agency,
                                          Region V, Library
                                          230 South Dearborn Street
                                          Chicago, Illinois 60604

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This report has been reviewed by the U.S. Environmental
Protection Agency and approved for publication.  Approval
does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection
Agency, nor does mention of commercial products constitute
endorsement or recommendation for use by the U.S. Government,
The position taken by the U.S. Environmental Protection
Agency on the disposal of uncovered, unmilled solid waste
is published as Appendix B.
An environmental protection publication (SW-62d.2) in the
solid waste management series

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                  MADISON'S MILLED REFUSE PROJECT

                             VOLUME II

                              CONTENTS                                PAGE

  I.  INTRODUCTION                                                      1

      A.   BACKGROUND                                                   1

      B.   ACKNOWLEDGEMENTS                                             5

      C.   DEFINITIONS                                                  6

 II.  CONCLUSIONS                                                       8

III.  OPERATION & ECONOMICS                                            11

      A.  GONDARD OPERATION                                            11

      B.  TOLLEMACHE OPERATION                                         27

      C.  TWO-MILL, TWO-SHIFT OPERATION                                53

      D.  OPERATIONAL COST OF LANDFILLING MILLED REFUSE                73

 IV.  CHARACTERISTICS OF MILLED REFUSE                                 77

      A.  PARTICLE SIZE AND DENSITY                                    77

      B.  FIELD DENSITY TESTS                                         111

  V.  VECTORS                                                         124

      A.  RAT AND FLY TESTS AT MADISON                                124
              STuo/es
      B.  RAT *fiS£S AT PURDUE UNIVERSITY                              147

 VI.  PRODUCTS OF DECOMPOSITION-LEACHATE AND GAS                      162

      A.  OLIN AVENUE FIELD STUDIES                                   162

      B.  LYSIMETER FIELD STUDIES                                     199

      C.  BIOTRON STUDIES                                             251

VII.  TREE GROWTH AND OTHER VEGETATION ON REFUSE                      295

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                               CONTENTS (continued)                          PAGE

  VIII.   OTHER OBSERVATIONS                                                   322

         A.   FIRE                                                             322

         B.   BLOWING, ODOR, ESTHETICS                                         334

    IX.   EUROPEAN OBSERVATIONS                                                336

     X.   APPENDICES

         A.   GONDARD COST CALCULATIONS                                       355

         B.   GONDARD PROJECTED ANNUAL TONNAGE                                 3 I I

         C.   SUMMARY DATA FROM GONDARD EXPERIMENTAL RUNS                      5 6 3

         D.   WAGE RATES AT MADISON REFUSE REDUCTION PLANT                     3/j"
             DURING GONDARD EVALUATIONS

         E.   GONDARD HAMMER WEAR AND COSTS                                    -^ 7
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                          TABLES (continued)                               PAGE

Table 2  Gondard Operating Production Rate vs. Grate Size - Tons Per
         Hour (Operating Time Only)                                          22

Table 3  Unadjusted Cost Data for Gondard Mill (June 1968 through
         May 1969)                                                           24

Table 4  Adjusted Cost Data for Gondard Mill  (June 1968 through
         May 1969)                                                           25

Table 5  Operating and Overall Production Rates for Tollemache Mill          42

Table 6  Operating and Overall Production (Dry Tons Per Hour)                43

Table 7  Comparison of Power Data for Tollemache Mill Alone (1970-71)        45

Table 8  Tollemache Milling Costs                                            51

Table 9  Stationary Packer and Haul Costs During Tollemache Evaluation       52

Table 10  Hourly Breakdown of Average Day                                    57

Table 11  Operational and Overall Production Rates (1972)                    60

Table 12  Power Consumption - Mills Combined  (1972)                          63

Table 13  Power Consumption - Stationary Compactor .(1972)                    64

Table 14  Milling Costs for Two-Mill, Two-Shift Operation (January
          through June 1972)                                                 66

Table 15  Labor Costs - Two-Mill, Two-Shift Operation (January through
          June 1972)                                                         67

Table 16  Breakdown of Labor Costs - Two-Mill, Two-Shift Operation
          (January through June 1972)                                        67

Table 17  Power Costs, Mills, Two-Mill, Two-Shift Operation (January
          through June 1972)                                                 68

Table 18  Power Costs, Mill Accessories, Two-Mill, Two Shift Operation
          (January through June 1972)                                        68

Table 19  Lighting Costs, Two-Mill, Two-Shift Operation (January through
          June 1972)                                                         69

Table 20  Plant Heating Costs, Two-Mill, Two-Shift Operation (January
          through June 1972)                                                 70
                                      iii

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                             TABLES (continued)                           PAGE

Table 21  Supply Costs, Hammer Maintenance, Two-Mill, Two-Shift
          Operation (January through June 1972)                            70

Table 22  Stationary Compaction and Haul Costs, Two-Mill, Two-Shift
          Operation (January through June 1972)                            71

Table 23  Landfill Costs Using Milled Uncovered Refuse (January
          through June 1972)                                               74

Table 24  Cost Comparison - Milled vs. Unprocessed Refuse Landfills
          (January through June 1972)                                      76

Table 25  Standard Sieves                                                  79

Table 26  Dates of Particle Size Tests                                     84

Table 27  Vibration Study on Landfill                                     100

Table 28  Compression Tests                                               101

Table 29  Laboratory Density Test Summary                                 107

Table 30  Summary of Springback Results                                   108

Table 31  Olin Avenue Field Density Tests (1967-68)                       112

Table 32  Wet and Dry Weights and Total Volume of In-Place Refuse vs.
          Compaction Time                                                 118

Table 33  Cover Material Volume and Machine Time Used in its Application  119

Table 34  Densities of Milled and Unprocessed Refuse Cells                120

Table 35  Percent Increase or Decrease of Densities Obtained Using
          Cell I as a Base                                                121

Table 36  Summary of Cell Construction                                    125

Table 37  Example of Tabulation of Results of Phases A, B, and C          130

Table 38  The Results of Phase A                                          132

Table 39  Rank of Daily Average Consumption According to Cell Type        133

Table 40  Results of Phase B                                              134

Table 41  Results of Phase C                                              136

Table 42  Average Number of Flies Counted Per Observation                 141
                                       iv

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                                       TABLES (continued)                              PAGE

           Table 43  Results of Cage Tests                                             144

           Table 44  Schedule of Samples to be Tested,  Series II                       154

           Table 45  Results of Purdue Rat Tests,  Series II                            155
•
           Table 46  Samples Tested at Purdue, Series III                               158

           Table 47  Summary of Test Cells - Olin Avenue Site                          166
*
           Table 48  Maximum, Minimum, and Average Values  of Various
                     Specific Ions                                                     171

           Table 49  Correlation Coefficient are for the Following Parameters vs.
                     Conductivity                                                      178

           Table 50  Nitrate-Nitrite Nitrogen Analysis (Mg/L)                          231

           Table 51  Water Budget Over Period May 1971 - May 1972                      248

           Table 52  Production Parameters as of July 5, 1972 (actual production in
                     units indicated and as percentage of  cell 4 results)              250

           Table 53  "Typical" and Target Composition of Refuse (Biotron Experiment)    255

           Table 54  Actual Refuse Composition for Biotron Experiment                  256

           Table 55  Refuse Weights and Densities in the Containers (Biotron
                     Experiment)                                                       257

           Table 56  Speed of Moisture Front, Milled Biotron Cell                      266

           Table 57  Speed of Moisture Front, Unprocessed  Biotron Cell                 267

           Table 58  Calculation of Evaporation Rates (Biotron Experiment)             268

           Table 59  Average Moisture Content - Biotron Cells                          270

           Table 60  Peak Temperatures in the Refuse (Biotron Experiment)              272

           Table 61  Percent Growth Increase of Various Plots                          300
s
           Table 62  Percent Growth Increase on Basis of Various Factors               301

*          Table 63  Percent Tree Survival on Basis of Various Factors                 302

           Table 64  Percent Tree Survival as of 1972 for  Various Species              304

           Table 65  Bulk Density, Perdent of Separates, Soil Texture, and Porosity    307

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                              TABLES  (continued)                           PAGE

Table 66  Composition of Soil Atmosphere at Various Depths                  310

Table A-l  Depreciation Date                                                356

Table A-2  "Actual" Power Costs  for Feed Conveyors and Mill                 357

Table C    Summaries of Experimental  Runs                                   364

Table D    Wage  Rates of Employees, Refuse Reduction Plant at Madison,
           Wisconsin (October 1,  1969)                                      386

Table G-l  Cost  of Materials Used                                           397

Table G-2  Cost  of Labor Used                                               397

Table G-3  Total Cost of Hammer Maintenance Program                         398

Table H-l  Annual Depreciation Data for Milling  System                      400

Table H-2  Annual Depreciation Data for Stationary Compactor and
           Final Transportation  System                                      400

Table 1-1  Summary of Experimental Run - Tollemache Mill, July  6,  1970  -
           October 9, 1970                                                  402

Table 1-2  Table of Labor Rates,  Effective July  6, 1970                     403

Table 1-3  Power and Utility Rates                                          404
T« I-/c 1'  «•>e»i/"  M(**n te*ia.ttie £<*• fa                                   . u,,
Table J-l  Summary of Experimental Run - Tollemache Mill, February 4,
           1971  to March 31, 1971                                           405

Table J-2  Table of Labor Rates  (Effective January, 1971)                   406

Table J-3  Power and Utility Rates                                          407

Table J-4  Equipment Maintenance  Rates                                      408

Table K-l  Average Annual Hourly  Wage                                      409

Table K-2  Average Annual Hourly Wage Rates  (Effective June 30,  1972)       410

Table L-l  Annual Depreciation Data for Milling  System                      414

Table L-2  Annual Depreciation Data for Stationary Compactor and  Final
           Transportation System                                           415

Table M-l  Power and Utility Rates                                          416
                                       vi

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                            TABLES (continued)                           PAGE

Table M-2  Equipment Maintenance Rates                                    417

Table N-l  Daily and Annual Tonnage Processed for Combinations
           of Mills and Shifts                                            419

Table N-2  Maximum Storage Requirements for Combinations of
           Mills and Shifts - Tons                                        419

Table N-3  Square Footage of Floor Storage Space Required For
           Combinations of Mills and Shifts                               420

Table N-4  Total Plant Size - Square Feet                                 420

Table N-5  Cost of Foundations, Buildings, Entrance, Roads, and Grounds
           For Combinations of Mills and Shifts                           421

Table N-6  Annual Labor Requirements and Costs                            422

Table N-7  Annual Mill Maintenance Costs                                  423

Table N-8  Annual Power Costs for Mill(s), Conveyor(s),
           and Compactors                                                 425

Table N-9  Relative Sizes of Buildings                                    426

Table N-10 Actual and Proportioned Power Consumption (KWH)                426

Table N-ll Actual and Proportional Power Consumption                      427

Table N-12 Average Monthly Power Consumption (KWH) For Lighting
           One and Two Shifts                                             427

Table N-13 Maximum Demand For Lighting - kw                               428

Table N-14 Annual Cost of Lighting for Combinations Of Mills
           and Shifts                                                     428

Table N-15 Actual and Proportioned Gas Consumption  (Heat) - One Shift     429

Table N-16 Actual and Proportioned Gas Consumption  (Heat) - Two Shifts    429

Table N-17 Annual Cost of Gas (Heat) One and Two Shifts                   430

Table N-18 Annual Water Costs for Combinations Of Mills and Shifts
           (Based on Cost of $0.002 Per Ton)                              430

Table N-19 Tractor and Trailer Requirements                               431

Table N-20 Number of Loads Per Day                                        431

Table N-21 Annual Operation and Maintenance Cost For Tractor and
           Transfer Trailer Operation Per Unit                            432

Table N-22 Annual Stationary Compactor Maintenance Costs                  432

                                      vii

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                             TABLES (continued)
PAGE
Table N-23  Annual Operation and Maintenance Costs For
            Front End Loader                                                433

Table N-24  Annual Cost of Foundation and Building                          434

Table N-25  Amortization* Data and Annual Costs                             434

Table N-26  Annual Cost for One Through Four Mills - One Shift              435

Table N-27  Annual Costs for One Through Four Mills - Two Shifts            436

Table N-28  Daily Landfill Labor and Equipment Requirements                 437

Table N-29  Annual Labor Costs - Landfill Operations                        438

Table N-30  Annual Operating and Maintenance Costs - Landfill
            Equipment                                                       438

Table N-31  Annual Projected Landfilling Costs                              439

Table N-32  Annual Cost of Milling, Milled Refuse Transfer System
            and Landfilling - One Shift                                     440

Table N-33  Annual Cost of Milling, Milled Refuse Transfer System
            and Landfilling - Two Shifts                                    441

Table 0-1  Range of Compositions of Madison's Solid Wastes (Wet Basis)
           by Federal Solid Wastes Program (November 1968)                  443
                               LIST OF FIGURES


Figure 1  Installation of Four Gondard Mills at Wiesbaden,Germany, 1966      3

Figure 2  Refuse Reduction Plant at Madison, Wisconsin, 1967                 12

Figure 3  Side Views of the Gondard Mill With Rejection Tower                13

Figure 4  Gondard Mill, Exploded View                                        14

Figure 5  Refuse Reduction Plant Exterior at Madison, Wisconsin, 1967        15

Figure 6  Interior View of Refuse Reduction Plant, 1967                      16

Figure 7  Gondard Mill at Madison, Wisconsin.  Housing Opened to Show
          Horizontal Rotor and Hammers                                       17

Figure 8  Tollemache Continuous-Metal-Belt Elevating Feed Conveyor           28
                                     viii

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                             FIGURES (continued)                         PAGE

Figure 9    Tollemache Vertical Shaft Hammermill Showing Feed and
            Take Away Conveyors                                            29

Figure 10   Tollemache Feed Conveyor Showing Tumbling Action of Refuse     30

Figure 11   Cutaway View of Tollemache Mill                                33

Figure 12   Vertical Shaft Tollemache Mill at Madison, Wisconsin           34

Figure 13   Hammer Pattern Used at Beginning of Evaluation Period          36

Figure 14   Tollemache Hammer Pattern in Use at Madison at end of
            Evaluation Period                                              38

Figure 15   Tollemache Hammers; New (Either Side), and After Four
            Days Use                                                       39

Figure 16   Tollemache Hammer and Portions That are Tipped                 40

Figure 17   Tollemache Mill Installation with Transfer Packer Station      48

Figure 18   Stationary Compactor With 35 Cu. Yd. Storage Hopper            49

Figure 19   Madison Refuse Milling Plant                                   54

Figure 20  Maintenance Shop for Welding and Repairs at Madison's
           Milling Plant                                                   55

Figure 21  Comparison of Moisture Content and Overall Production Rates     62

Figure 22  Particle Size Distribution Obtained by Sieving Compared
           to That Obtained With a Ruler                                   82

Figure 23  Particle Size Distributions Obtained at Different Refuse
           Moisture Contents                                               83

Figure 24  Apparent Effect of Hammer Wear on Particle Size Distribution    85

Figure 25  Apparent Effect of Hammer Wear on Particle Size Distribution    86

Figure 26  Particle Size Distributions of Various Refuse Samples Taken
           From Tollemache Mill                                            88

Figure 27  Particle Size Distributions of Various Refuse Samples Taken
           From Gondard Mill                                               89

Figure 28  Particle Size Distributions of Various Refuse Samples Taken
           From Both Gondard and Tollemache Mills                          90

Figure 29  Refuse Moisture Contents Measured Over a One-Year Period        92

Figure 30  Container Used for Compression Tests                            94

Figure 31  Iron Plat Used for Compression Tests                            95
                                      ix

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                            FIGURES (continued)                          PAGE

Figure 32   Small Box Used in Compression Tests                            97

Figure 33   Compression Machine With Air Hammer in Place, Used to Compact
            Milled and Unprocessed Waste During Laboratory Investigations  98

Figure 34   Universal Testing Machine Used for Compression Tests           99

Figure 35   Compressibility Tests on Refuse                               105

Figure 36   Effect of Bridging on Density of Refuse                       110

Figure 37   One of Three 2,000 Cu. Yd. Cells Constructed At Truax
            Landfill to Conduct Field Density Tests for Milled and
            Unprocessed Wastes                                            113

Figure 38   Pit Partially Filled with Milled. Refuse During Density Tests  115

Figure 39  Pushing Milled Refuse With a Steel-Wheeled Compactor           117

Figure 40  Cell and Bait Station Map                                      126

Figure 41  Bait Station Used During Rat Study Phase of Vector Investi-
           gation at Olin Avenue Site                                     128

Figure 42  Scudder Grille Used to Estimate Numbers of Flies on Milled
           and Unprocessed Refuse                                         140

Figure 43  Screened Cages Used During Fly Survivability Tests, 1969       143

Figure 44  Pen for Norway Rats at Rodent Test Center at Purdue University,
           Lafayette, Indiana                                             149

Figure 45  Typical Cage Used in Studies Conducted at Purdue University    151

Figure 46  Coarsely Ground Refuse Used for Rat Tests at Purdue
           University                                                     157

Figure 47  Cell Locations, Olin Avenue Test Site                          165

Figure 48  Leachate Production, Combined Refuse Cells                     174

Figure 49  Leachate Chemical Oxygen Demand (COD), Combined Refuse Cells   176

Figure 50  Leachate Grams of COD per day, Combined Refuse Cells           177

Figure 51  Leachate Conductivity, Combined Refuse Cells                   179

Figure 52  Leachate pH, Combined Refuse Cells                             182

Figure 53  Leachate Production, Special Cells                             184

Figure 54  Leachate Chemical Oxygen Demand, Special Cells                 185
                                        x

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                        FIGURES (continued)                              PAGE

Figure 55   Leachate Grams of COD per day, Special Cells                  186

Figure 56   Leachate Conductivity, Special Cells                          187

Figure 57   Gas Data, Combined Refuse Cells                               192

Figure 58   Gas Data, Special Cells                                       193

Figure 59   Typical Lysimeter Bed Cross-Section                           200

Figure 60   Lysimeter Bed Showing Bituminous Layer and Reservoir
            While Plastic Sheet was Being Placed                          201

Figure 61   Lysimeter Bed Ready for Filling With Refuse                   203

Figure 62   Diagram of Lysimeter Bed Layout                               204

Figure 63   Lysimeter Bed Being Filled With Unprocessed Refuse            205

Figure 64   Lysimeter Bed Being Filled With Milled Refuse                 206

Figure 65   Cow Tank and Barrel Arrangement as Used to Collect Runoff
            From Each Lysimeter                                           207

Figure 66   Volume of Leachate Production From Lysimeters                 211

Figure 67   Refuse Moisture Content, Lysimeter Study (Cells 1 & 2)        213

Figure 68   Refuse Moisture Content, Lysimeter Study (Cells 3 & 4)        214

Figure 69   Cumulative Leachate Production From Lysimeter Cells           216

Figure 70   Leachate Chemical Oxygen Demand From Lysimeter Cells          218

Figure 71   Chemical Oxygen Demand Production, Lysimeter Study            221

Figure 72   Cumulative COD Production From Lysimeter Test Cells           223

Figure 73   Conductivity of Leachate From Lysimeter Test Cells            225

Figure 74   Alkalinity of Leachate From Lysimeter Test Cells              227

Figure 75   Total Hardness of Leachate From Lysimeter Test Cells          228

Figure 76   Calcium Hardness of Leachate From Lysimeter Test Cells        229

Figure 77   Chloride Concentration of Leachate From Lysimeter Test Cells  230

Figure 78   Iron Concentration in Leachate From Lysimeter Test Cells      232

Figure 79
Ammonium and Organic Nitrogen Concentrations of Leachate
From Lysimeter Test Cells
                                                                          233
                                      xi

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                          FIGURES (continued)                            PAGE

Figure 80   Phosphate Analysis of Leachate From Lysimeter Test Cells
            (Cells 1 & 2)                                                 235

Figure 81   Phosphate Analysis of Leachate From Lysimeter Test Cells
            (Cells 3 & 4)                                                 236

Figure 82   pH of Leachate From Lysimeter Test Cells                      237

Figure 83   Refuse Temperature in Lysimeter Test Cells (Cells 1, 2 and 3) 239

Figure 84   Refuse Temperature in Lysimeter Test Cells (Cell 4)           240

Figure 85   Leachate Temperature From Lysimeter Test Cells                242

Figure 86   Gas Composition (Upper Probes) of Lysimeter Test Cells        244

Figure 87   Gas Composition (Lower Probes) of Lysimeter Test Cells        245

Figure 88   Precipitation During Lysimeter Test                           247

Figure 89   Runoff Measured From Lysimeter Test Cells                     247

Figure 90   Container Packed With Milled Refuse and Used in the
            Biotron Studies                                               254

Figure 91   Cumulative Volume of Rainfall and Leachate vs. Time,
            Biotron Study                                                 261

Figure 92   Refuse Moisture Readings at Middle Level, Biotron Study       262

Figure 93   Refuse Temperature at Middle Level, Biotron Study             271

Figure 94   Cumulative COD and IDS vs. Cumulative Leachate Volume         274

Figure 95   Cumulative Total Hardness and Alkalinity vs. Cumulative
            Leachate Volume                                               275

Figure 96   Cumulative Total and Ortho Phosphate vs. Cumulative
            Leachate Volume                                               276

Figure 97   Cumulative NH^-N and Organic Nitrogen vs. Cumulative
            Leachate Volume                                               277

Figure 98   Cumulative Chlorides and Iron vs. Cumulative Leachate Volume  278

Figure 99   COD - Total Production and Concentrations vs. Time            281

Figure 100  TDS - Total Production and Concentrations vs. Time            282

Figure 101  C02 Content in Supply and Exhaust Air                         285
                                      xii

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                             FIGURES (continued)                          PAGE

Figure 102  Total Hydrocarbon as CH^ in Supply and Exhaust Air             286

Figure 103  Cumulative Hardness and Chlorides vs. Volume                   291

Figure 104  Cumulative COD and IDS vs. Volume                              291

Figure 105  Conductivity and IDS vs. Volume                                292

Figure 106  pH and COD vs. Volume                                          292

Figure 107  Total Hardness and Chlorides vs. Volume                        293

Figure 108  Some Products of Volunteer Vegetation on Olin Avenue
            Milled Refuse Landfill, Madison, Wisconsin                     317

Figure 109  Heavy Vegetation Growing on a Test Cell of Milled Refuse       318

Figure 110  Fire Deliberately Started on Fresh Milled Refuse Caused
            Smoldering, but Remained on the Surface and was Easily
            Extinguished                                                   320

Figure 111  Wind-Blown Film Plastic From Milled Refuse Landfill            321
                                      xiii

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                             I INTRODUCTION

I-A - background

     This volune contains reports of the major research efforts undertaken
Jurinn a project in Hadison, Wisconsin, to demonstrate the feasibility of
nilling refuse for landfill ing vithout daily cover.  The demonstration
project was conducted between 19^6 and 1972 under grants fron the Depart-
ment of Health, Education, and 'ielfare and the Environment Protection
Agency.

     Tfie chapters in this volume are meant to provide a detailed account of
individual  research projects.  This volume, therefore, should be especially
useful to engineers and others who need to review the data used in reaching
the conclusions v/hich form the basis of volume I of this reoort.

     The project began as a practical demonstration to investigate the
concept of milling refuse for landfill disposal without daily cover.  It
was intended ta gather data on the operation and cost of refuse milling
equipment, the use of milled refuse in landfill, and the characteristics
of milled refuse—all from a practical standpoint.  Project personnel
ended up doing extensive research work, on both milled and unprocessed
refuse, v/hich was far removed from the  idea of a demonstration project.
The major reason for the vast amount of research involved in this demon-
stration project was the need to  show numerically that milled refuse
without daily cover lives UD to  the glowing iiraise offered by European
landfill operators.  As a result, it was necessary to design experiments
involvinn rats, flies, leachate,  nas, trees, etc., which hopefully would
quantify such factors.  While so^e crude techniques for making measurements
on these parameters existed in the solid waste field, only n few suggestions
could be gleaned from the literature or from similar projects.  It was
therefore necessary tc pioneer in such areas as to hov/ to measure particle
sizes of refuse and hew to compare the occurrence of flies on a sanitary
landfill face and the surrounding area with their occurrence on a milled
refuse Disposal site.

     In drawing conclusions and developing a report, the investigators in
this project used not only the numerical data but also seven years of field
experience and observations to present the story.  It should also be kept in
mind that there is a difference between the idealized, textlook views of the
environmental aspects of ? covered unprocessed landfill and what occurs in
the fiold durinn years of operation.  Thus, comparisons between milled and
unprocessed refuse must !>e leased on actual day-to-day field operations and
not on theoretical considerations.

     ;iillinn \?as begun in furcpe to provide material suitable for com-
postinn.  The original single- or double-rotor hammer mills were designed
to handle homor;oneotis materials; thus unnrindable items had to b" manually
sorted and removed.

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     A French manufacturer of grain-grinding nachines made the crucial
observation that led to the cannMlity of nillinq heteroneneous material
such as refuse.  He was trying to learn why his qrain mill was unable to
grind high-noisture corn, <->nd durinn an investigation of this problem he
had a portion of the cover on the machine cut out.  He observed that dry
grain particles were readily ground.  The softer, spongier, moister grains,
however, remained uncround and were accelerated through the opening in  the
top of the machine.  The manufacturer of grain grinders thus learned that
nongrindable objects can be ballistically separated from qrindable objects
ir a mill.  The ballistic rejection feature of the mill was awarded U.S.
patent 3,082,9^3 on March 26, 1963.

     The idea of ballistically separating nonm'llable refuse through a
"chimney* above a hammermill was developed into a test machine which was
installed in Meaux, France in the early 1950's.  Since there was no com-
posting plant in the vicinity, the milled refuse was simply deposited on
land near the machine.  Amazingly, the  milled refuse did not create a
nuisance.

     The original nil! at 'leaux was fed by hand at the inlet opening.  It
soon became apparent that a mechanical feeding mechanism would be needed  to
maximize the machine's output.  Development of mechanical feeding machinery
took another two years, however.

     Hy 1970 there were over 50 installations employing this feeding and
nillinq equipment in western Europe (Figure l ).  Almost all landfilled
the milled refuse without daily cover.

     fjy the mid-1960-s, the first Oondard plant was in operation in North
America — at Montreal, Canada.  In this plant, two ^ondard mills are used
in a parallel arrangement for refuse milling by a commercial, salvaging
company.  About 25 percent of the tonnage brought to the mill during its
first yeors of operation was salvaged and sold.  The major item salvaged
was paper.  The remainder of the milled refuse was dumped along with
unprocessed refuse in an uncontrolled fashion; thus it was difficult, to
draw conclusions about many aspects of landfillinq milled refuse from the
Montreal operation.

     European experience, however, has indicated that handling riilled
refuse at a landfill site is simple and convenient.  It is merely dumped
and graded as desired.  Since milled refuse is relatively uniform in size
inc' composition, compaction and settlement are even.  The material provides
excellent support for rubber-tread vehicles, and since glass objects are
reduced to tiny pieces, damage to tires of landfill machinery is greatly
reduced.  The nuisance caused by blouinn naoer and dust produced by packing
machinery is greatly Deduced,  the danger of fire in the landfill is nreatly
lessened.  Many vectors, especially rates and flies, ere reduce^ in numbers
or eliminated from the landfill,  Milled refuse is esthelically noro oleas-
ing t'nan unprocessed refuse and therefore is more ro^lily accepted hy the
public.  Finally, accnrdim to Furopean claims, miller refuse that iias
been landfi lied ^aes not require daily covering.

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     The Hell Conpany of Milwaukee, Wisconsin, manufacturers and marketers
of truck bodies for solid waste collection, learned of the rtondard milling
process throuqh sales activities in France, Switzerland, Netherlands, and
Germany.  Company representatives were impressed by the Eurooean claims of
tie attractive features of milled refuse and thus set out to find a city in
the United  States to undertake a test project involving refuse milling.

     fn incentive to notential users of the new milling system v/as the
r.olid ','astes Act of 1965 which provided matching funds for projects which
would demonstrate on a production scale new  methods of mananing solid
waste.  Efforts to interest a community in Milwaukee County in trying
the new system proved unsuccessful when it appeared that the project
would interfere with development of a county-wide incineration system.

     Continuing their search, the Meil representatives contacted Professor
Gerard Rohlich nf the University of Hisconsin-'ladison College of Engineer-
ing.  Professor Rohlich felt that the system warranted investigation and
encouraged Madison's Director of Public Works, City Engineer, and Superin-
tendent of Streets and Sanitation to investigate the possibilities and to
view the '1ontreal operation.

     An inspection trip to the Montreal facility took place in February
1%G, following a prolonged thaw.  The haul roads into  the landfill site
were almost impassable to automobiles.  However, the traffic-bearing Quality
of the uncovered milled refuse in the landfill was remarkable.  The visitors
were able to walk on the  refuse surface without overshoes, and loaded trucks
sank only three or four inches into the material.

     The ease of operation at the Montreal landfill, even under adverse
conditions, convinced tin Madison officials to recommend to the Madison
Common Council that they be oermitted to apply for a grant to fund a demonstra-
tion project.  The proposed project would investigate European claims that
milled refuse can be landfilled without daily cover as well as determine
'./hat modifications would be  necessary to adapt the system to refuse gener-
ated in this country.  The cost of such a system would also be carefully
documented, and  the characteristics of milled refuse would be studied.
     In y-pril 196C, the Common Council approved the submittal of a
proposal to the Deportment of Health, Education, and Welfare and desinnated
the 01 in Avenue landfill site as the location of a proposed plant.

     The City of ''adison received a three-and-one-half-year grant,
number IJ-r)r>I-UI-00004, from HE.,' in June 19fi'~>.  The grant, vas renewed
ant! expended several tines to cover additional work.

     The aoneral objectives of the demonstration project have been:
     1.  To evaluate oneration and economics of the Honr'^M and Tollenache
mills, the associated conveyors, the final disposal system, and tiie milling
plant.

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     2.  To investigate the properties of milled refuse itself.

     3.  To verify or disprove European claims that milled refuse can
be used in landfills without daily cover.

     The participants in this milled refuse project included:  1) the
City of Madison, which provided the plant site, site improvements,
operating personnel, matching funds, and, of course, the refuse; 2) the
Heil Company of Milwaukee, which furnished and installed the equipment
and provided matching funds; under terms of a purchase option contract,
Madison bought the equipment in 1969 after it proved successful; 3) the
University of Wisconsin-Madison, which collected data and evaluated the
project.

I-B - Acknowledgements

     The persons who initiated the refuse reduction project in Madison
included Arnold Meyer, Vice President of the Heil Company; Gerard Rohlich,
Professor of Civil Engineering, University of Wisconsin-Madison; Edwin
Duszynski, Director of Public Works, City of Madison; John Thompson,
former City Engineer, City of Madison; and James Brophy, Superintendent
of Streets, City of Madison.

     Overall responsibility for the project has been in the hands of
John J. Reinhardt, Principal Civil Engineer, City of Madison; and Robert
K. Ham, Associate Professor of Civil and Environmental Engineering,
University of Wisconsin-Madison.  Evaluations were carried out under
direct supervision of Warren K. Porter and Gerald W. Sevick, Project
Specialists.

    The project has had several Environmental Protection Agency project
officers of which the primary ones were David Arella and Roger Graham.

    Major investigations were conducted by Charles R. Anderson, Larry
Hendrickson, James R. Boyle, Rameschandra Gawalpanchi, Everett W.
Clodfelter, Fred Courtsal, Gier Wigdel, Vincent Geier, Walter L. Gojmerac,
and Daniel M. Benjamin.

    Assisting in the project have been Gary Boley, Robert Karnauskas,
Kenneth Brunner, Herbert Hanneman, David Potwin, Richard Presney,
Ellsworth Fisher, Earl Ulsrud, Charles Haas, Raymond Dillabough,
Warren Kimberley, Richard Steinhofer, William Martin, Mary Smits,
Eugene Davenport, and Al Kelly.

    Student assistants have included Wendy Arndt, Douglas Lindquist,
William Merry, Robert Schmidlen, and Daniel W. Benjamin.

    Production of the final report for this project has been the
responsibility of John Wolf and Austin Henry.

    Special recognition is given to Doris Habich for typing and retyping
the project's numerous reports over the past six years.

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I—C - Definitions

          Several terms used throughout this volume require short definitions.
Most of the definitions are adapted from APHA Municipal Refuse Disposal,
Chicago, (1970), and the EPA Publication Solid Haste Management Glossary
(SW-108ts), 1972.
          1) Refuse (also called solid waste). Useless, unwanted, or discarded
material.  This report is concerned primarily with residential (also called
domestic) and light commercial refuse — that is, all  solid waste that
normally originates in a residential environment.  Industrial, institutional,
and large quantities of commercial refuse are generally collected by
private firms in Madison and are not normally milled.Large tree cuttings,
bulky items, and construction-demolition debris are also handled separately
at Madison.
          2) Garbage (also called food v/aste). Animal  and vegetable waste
resulting from handling, storage, sale, preparation, cooking, and serving
of foods.
          3) pubbish.  A general term for solid waste  — excluding garbage and
ashes -- taken from residences, commercial  establishments, and institutions.
          4) Milled °efuse.  Refuse that has been mechanically ground, siiredded
or pulverized.
          5) Unprocessed Refuse.  To avoid confusion,  this term will be applied
uniformly to utinillou, crude, or raw refuse.
          G) Cell.  ^ volume of compacted solid v/aste  which nay be enclosed by
natural soil or cover material in a sanitary landfill, not covered as in the
c-Tse of test volumes of milled refuse, or enclosed in  concrete beds in other
test situations.
          7) Sanitary Landfill. A method of disposing  of solid waste on land by
utilizinq sound engineerino and planning principles, by spreading the waste
in layers, conpacting it to the least practical volume, and covering it with
soil at the end of eacii working day.
          8) Bulky Items.  Madison routinely collects  large, bulky items such as
furniture, tiros, and natresses separately.  Such material is not milled but
landfillcH separately.
          !?) Rejects.  These are items which the mills ballistically separate
because t.'ioy cannot bo pulverized to the desired particle size.
          I1")) Cover.  Soil which is olacec' over material in a sanitary landfill
at specified intervals, usually daily.
          11) Vector,  An organism that is capable of transmitting a pathogen.
          12) Leachate.  Liquid that has percolated throunh solid waste and has
extracted, suspended, or dissolved material from it.
          11) Actual Refuse Density.  The figure derived by dividing the weight
of a portion of refuse by the volume of that refuse.
          14) Effective Refuse Density.  The figure derived by dividing the
weight of a   load of   refuse by the volume of landfill space it takes up
(includino any cover).
          15) Operational Production Pate.  Tons processed durino the tine in whii
a mill is actually running.  Down tine is omitted from this finure,  Thus, it
is a measure of a mill's efficiency.
          K<)  Hown Tine.  In evaluations of the mills separately, time when a
mill was shut Jcwn d^e to mechanical problems.  In evaluations of the two-mill
operatioii, all tines durinn v/hich the mills were not grinding refuse, between
the initirl start-up of the mill to the shut down at completion of the
production day (e.g., any time the mill is not running during normal
working  hours).

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      17) Overall  Production Rate.   Tons  of refuse processed  divided  by time
durinq which the mill(2S) was grinding,  plus down time.   Thus,  it  is  a  measure
of the plant's efficiency.
      18) Millfilling. An engineering method of disposing of  solid waste on
land without daily cover by milling the  waste,  spreading  it in  layers and
compacting it to the smallest volume practical.

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                              II  CONCLUSIONS

     Among the conclusions of the demonstration  milling project in  Madison
between I960 and 1972 are the following:

     1.  As operated at Madison,  the Gondard  hammermill  has  a capacity of
         9 tons per hour with a 5-inch  grate, and the  Tollemache hammermin
         has a capacity of 14 tons per  hour with a 34-hammer pattern.   The
         grate size and hammer pattern  were chosen to  grind  refuse  as
         coarsely as possible without producing  problems of  blowing litter
         at the landfill.  (On a  dry-weight basis, between 80 and 90 per-
         cent of the particles produced by both  mills  pass through  a 20
         inch screen).  Evaluations of  the two mills separately showed
         that the Gondard mill uses nearly as much electrical  energy as
         Tollemache mill while producing  only about 60 percent as much
         milled produce as the Tollemache.

     2.  /^side from some minor problems with  the mills themselves,  most
         of the early operational problems were  associated with conveying
         refuse to the mills and  carrying milled refuse to the landfill.
         The steeply inclined feed conveyor and  the stationary compactor
         with a 75-cu.-yd. transfer vehicle used with  the Tollemache nil!
         have graatly increased the ability of the Madison plant to handle
         unprocessed and milled refuse  on a production basis.

     3.  Residential and light commercial refuse as collected at Madison
         can be milled in either type of  hammermill without  presorting
         and with negligible downtime due to  mill stopoage.

     4.  filled refuse has been left in a landfill without cover for up
         to 6 years, and no complaints  have been received about odors,
         unsightliness, blowing litter, rodents, or insects.  Public
         acceptance of the nil ling plant  and''the landfill has been
         unusually nood.

     5.  Experience with milled refuse  without daily coyer indicates that
         the quality of operation at this type of landfill is superior to
         sanitary landfill operations at  Madison with  respect to travel
         over tha fill and ?t the face  of the fill, dust, tracking  of
         trucks on highways, appearance during operating hours and  main-
         taining a uniformly high level of operation during  cold and wet
         weather.  Fully loaded trucks  weighing  nearly 73,000 Its.  can
         drive on milled refuse in inclement  weather.   Also, tire prob-
         lems hav2 not been caused by travel  on  uncovered np'lled refuse.

     6.  Experience and specific testing  have shown that there is less of
         fire iiazard with milled th/tn with unprocessed refuse.
         Rats are not able to survivo on properly milled refuse containing
         up to 20 percent v.-nt garbage on a wet weight basis.   Based on tin's
         finding and on observations of the landfill  site, there is very
         little likelihood of rat infestation and survival in d milled
         refuse landfill.
                                     8

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 8.   Under optimum weather and moisture conditions, flies probably
     can breed in freshly milled refuse; however, once such refuse
     has aged several months, this ability is evidently lost.  Tests
     with the Gondard mill showed that a very large percentage of fly
     maggots passing through the mill during normal operation were
     killed.  Fly counts and operating experience at Madison indicate
     that there is no fly nuisance problem associated with milled refuse.

 9.   Compaction of cover soil, as well as production of methane and
     carbon dioxide by underlying refuse, created poor aeration con-
     ditions for tree roots and thus led to a high mortality of trees
     planted on milled and unprocessed refuse cells after 2 years.
     White ash and crab were the most successful of the tree varieties
     planted in that they developed effective lateral root systems in
     the densely compacted cover soil.

10.   Actual refuse density of milled refuse on a wet-weight basis was
     found to be approximately 27 percent greater than the actual refuse
     density of unprocessed refuse given equal compaction.  Under the
     same conditions, the effective refuse density of milled refuse
     was calculated to be nearly 35 percent greater than that of unpro-
     cessed refuse.

11.   Leachate production occurs at a faster rate in milled uncovered
     cells than in covered cells, milled or unprocessed.  In the absence
     of cover, milled refuse develops a relatively mature degradation
     pattern and thus lowers the organic pollution load leaving the refuse
     in leachate.  Before a mature degradation condition develops in
     milled refuse, large quantities of organics in particular are
     leached from milled refuse.

12.   The covered unprocessed refuse cells never produced organics at
     as high a rate as did the milled cells during initial stages of
     decomposition; however, the unprocessed cells continued to produce
     organics at a fairly consistent rate throughout the duration of
     the project.  Thus, the milled refuse cells could be characterized
     as producing more leachate contaminants during initial stages of
     decomposition but less during later stages of decompostiion than
     the unprocessed refuse cells.

13.   A water budget analysis shows that in Madison, Wisconsin, about
     68 percent of incident precipitation on covered refuse in a landfill
     evaporates, while the remaining 32 percent is divided almost equally
     between runoff and infiltration (leachate).  Virtually no runoff and
     slightly more evaporation occurs with uncovered milled refuse.

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14.   In the first evaluation of the Gondard mill with a 5-inch grate
     in mid-1968, a per-ton cost of $7.75 - including process and hauling
     costs but excluding landfilling costs - was experienced.  When this
     figure was adjusted to exclude factors related solely to the ex-
     perimental aspects of the operation, a comparable cost of $5.33 per
     ton emerged as a reasonable estimate for a production facility.
     During an evaluation of the Tollemache mill in the summer and fall
     of 1970, a cost of $4.74 per ton for milling and hauling (but
     not landfilling) was calculated.  A winter evaluation early in
     1971 yielded a cost per ton of $5.71.  These two Tollemache figures
     are based on the weight of refuse as received at the plant and
     include increased labor costs incurred during the second evaluation.

15.   For a two-mill, two-shift operation during the first 6 months of
     1972, a milling cost of $3.90 per ton was determined, based on
     23,317 tons milled; another $0.48 per ton must be added to this
     figure to cover stationary compaction and hauling less than 1/2
     mile.  The operating costs of landfilling for the first 6 months
     of 1972 in Madison were $0.99 per ton for milled refuse and $3.00
     per ton for unprocessed refuse, excluding any land and development
     costs.  During this period, regular sanitary landfills in Madison
     handled about twice as much material as did the milled refuse landfill.

16.   Based on the findings of this study, a cost of $2.75 per ton of
     milled refuse was projected for a two-shift, two-Tollemache-mill
     operation.  This figure includes milling, hauling less than 1/2
     mile, and landfilling and assumes a continuous supply of millable
     refuse.  The .City of Madison will continue milling refuse at the
     Olin Avenue Milling Plant.  In the Summer of 1973, the Olin Avenue
     millfill operation will be completed.  The City has recently acquired
     another landfill approximately nine miles from the milling plant.
     The milling plant will serve as a central processing and transfer
     station from which the milled refuse will be hauled to the new
     millfill facility.

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                   Ill OPERATION AND-ECONOMICS

III-A - Gondard Oppration

DESCRIPTION

 The Gondard hannermm installed at the Madison Refuse Reduction
Plant in 1967 is equipped with the conventional number of 48 1-3/16 x 4
x 11 in. swinging hammers on four shafts.  The 15-lb.hammers are driven
at 1150 r.p.m. by a Louis Allis 150 hp motor.  A chimney over the mill
permits ballistic rejection of large, unmillable objects.

    To keep costs low, it was decided to build as small a building as
possible to house the Gondard mill.  This resulted in a complex system
of three feeding conveyors  (Figure 2).  The original motors for all three
conveyors were variable speed Sterling motor reducers.  These were control lee
by a special unit that permitted the operator to vary the speed of the
two rubber belt conveyors or the conveyor in the 75 cu. yd. feed bin.
The control unit also contains a system to automatically stop all three
conveyors when pov/er input to the mill motor exceeds 125 percent of rated
load for 5 consecutive seconds.

    The orininal discharge conveyor was a conventional transfer conveyor
suspended with a trolley that permitted swinging from one to the other
of two 10 cu. yd portable load lugger bins.

    Figure 2 presents a perspective layout of the original plant as it
was completed in the spring of 1967; it also serves as a flow diagram
and indicates the machinery layout.  Figure 3 is a side view of the mill
and rejection tower.   Figure 4 is an exploded view of the grinder itself,
and Figures 5 and 6 show the exterior and interior, respectively of the
original Madison Refuse Reduction Plant.  Figure 7 is the Gondard mill
with the housing open to show the horizontal rotor and the hammers.

PROBLEMS WITH ORIGINAL EQUIPMENT

    The Gondard mill and conveyors were imported from France on the basis
of satisfactory operations in Europe.  Almost immediately, however, it
became apparent that refuse generated in Madison was different from European
refuse.  For example, Madison's refuse contains more large items such
as boxes.  These differences, as well as mechanical problems, required
modification of the nondard system after installation at Madison.

    Some of the modifications included:

       1) Addition of 6-in.cleats to supplement the 3-in.cleats in the
feed bin conveyor for handling the larger items in Madison's refuse;
                                 11

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       2) Installation of spray bars around the area where the refuse
leaves the bin conveyor and at the entrance to the mill to help reduce the
dust problem;

       3) Redesign of several components of the feed mechanism to prevent
jaris and improve uniformity of feed;

       4) Revision of the servo motor on the bin feeder to allow rapid
change of conveyor speeds.

    The lO-cu.-yd. collection bins proved unsatisfactory when the milling
system operated at 2/3 of capacity.  This aspect is discussed further in
the "Operation" portion of this section

'lAINTENAriCE

    The hammers, of course, are subject to the greatest abrasion in this system,
The rods on v/hich the hammers swing require replacement about four times
per year when operating on a one-shift basis; the spacers between the rotor
disks have a similar lifespan.  Other erodable elements are the grates
and the liner or wear plates.  These are maintained by arcweld
hard surfacing.  The maintenance program, when properly executed, can
be carried out daily during the one hour cleanup period.  Only if grate
or liner replacement is required should it be necessary to perform such
work on overtime.  The fact that all elements of the hamrnermill are relatively
thick and can be welded in the downhand position makes it easy to train
personnel for this work.

    Experiments with "tipping" or "hardfacing" the hammers were begun
in February 1968.  Results of tipping medium hard steel (SAE 1060) hammers
were extremely good.  Tonnage of refuse milled with one set of hammers
was nearly doubled.  Attempts to tip harder steel (SAE 1090) hammers resulted
frequent fractures.   Heating these hammers before tipping improved the
situation, but fractures  still occurred.

    Experience has shown  that a set of SAE 1060 hammers, properly hardfaced,
can mill over 1000 tons of refuse.

OPERATION

    Incoming refuse (see  Appendix  N) is first weighed and then emptied
inside the building, cither in the storage bin or on the floor when the
bin is full.  A fronten.1  loader is used to push refuse from the floor
int"  •!i • rto> a o !i s os ne  !»^.  T;K- coninnation of refuso storage in
                 f1 or '/?5 ., ;< ;er to (.lininate thp "OPH  nr  r1 overhead
                      ' t'>  n'nirn'zc Imndlina the reiuso.

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    The original system transporting the refuse from mill to landfill
was a load lugger detachable container system consisting of a flatbed
truck with hydraulic arms to lift a 10 cu. yd. bin onto the bed.  Three
bins were provided initially.  One bin was placed under the reject chute
and could hold the items rejected during one or two days of milling.  The
other two containers were located at the end of the conveyor bringing refuse
from the mill.  The conveyor was mounted on a track so that it could be
switched from one container to the other.  When one container was filled,
a man stationed at the truck leveled the load, switched the conveyor to
the other container, took the full load to the landfill, and replaced
the emptied container in its original location.  By the time he returned,
the second container was nearly full.  This man was thus continually occupied
in emptying containers.  Because of the fluffy nature of the freshly milled
refuse, these 10 cu. yd. containers held only 2,500 to 2,000 Ibs.

    A change was made to mechanical compaction trucks.  From January through
November, 1968, two old packer trucks were pressed into emergency service.
A person was needed to actuate the packing mechanism every few minutes.
Adding to the cost of this equipment were frequent repairs.

    During 1968, two models of 20 cu. yd. packer trucks were tested.  Neither
was able to keep pace with the volume of refuse discharged from the mill.

    The final collection and transportation system tried during the Gondard
tests involved two prototypes of a 25 cu. yd. truck to be manufactured by
the Heil Company.  These trucks had a packing mechanism that could be
continously cycled by mechanical means.  This system reduced both manpower
needs and the number of trips to the landfill.

PRODUCTION

    During the year of experimental trials with the Gondard system, the
grate at the bottom of the mill, through which the milled refuse is driven,
was changed systematically to determine the optimum grate size.  The
grate size is the space between bars of the grate.  Considerations in
optimization included machine capacity, operating costs, landfill space
required, and particle size.  Initially, plans called for using 2, 3 1/2,
4, 5, and 6 1/4 in. grates; however, tests with the 2 in. grates were
discontinued almost immediately because they yielded particles finer
than required for landfill and were slowing production.

    The optimum size for use in Madison was found to be 5 in.  This yields
the highest production,9 tons per hour, at lowest costs without producing
blowing paper problems in the landfill.  The production rates for the
3 1/2 and 6 1/4 in. grates were 8.6 and 9.4 tons per day, respectively,
during the tests.

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    Tables 1 and 2 show production rates at various seasons and with
different grate sizes.  Two production rates were calculated: one based
on machine operating time alone and the other based on machine operating
time plus down time.  Thus, "operating" production rate is tonnage processed
during the time the machine is actually running, while "overall" production
rate is tonnage processed during mill operating time plus down time.  Not
included in the overall rate is time lost because the plant is out of
refuse, because of truck breakdowns, or because of the time lapse from
arrival of the first load and the start of milling operations.  These
factors are not included because they are not due to machinery limitations
but due to limitations in the plant itself.  Time lost because of these
nonmachine problems does, however, have to be taken into account in final
cost analysis,

    Theoretical capacity was not reached, probably because of material
handling problems associated with the heterogeneous nature of refuse.
A load factor, or ratio of power consumed to theoretical power consumption.
wsas computed as a rouah indicator of how hard the machine worked compared
to its theoretical capacity.  The average load factor ranged from 0.6
to 0.7, depending upon the grate size used.  This factor has not been
used to calculate a theoretical machine capacity, as such is a rather
tenous concept.

    Early in the project the rejectable items were separated into a bin
and weighed from September 1967 through January 1968.  During this time,
it was found that between 1 and 7 percent by weight of the total refuse
could be ballistically separated when the reject chute extended 27 feet
vertically above the prill.

    Appendix  C presents the production data from the Gondard experimental
runs.

COST DATA

    Cost data are presented in this section for the third year of this
demonstration project, from June 196R through May 1969.  Although it  is
proper to renort the costs incurred in the existing plant, one must be
cautioned about adapting these costs to other installations because this
is a pilot plant demonstration project whose operation is probably more
expensive than that of future plants.  One also needs to recognize the
regional variations in labor, power costs, heating costs, and depreciation
methods.  Inflation durinn the years since this study was underta\en nust
also bo considered.  One is referred to the subsequent section on cost
proj^conris frr i nore acci. ^e indication of what \ uture plants night
cost.  ":r:,o :> "v>c" '-T'-  ;  '' MO costs r er ton ranging from '"4.96 for
one 'ill ono*">t/id one    ,   L   .",13 for four mills operated v;o shifts.
                                 20

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                            TABLE 1
 Gondard Overall  Production Rate  Vs. Grate Size - Tons Per  Hour
                    (Operating Plus  Down Time)
Period
Fall 1967
Winter 1967-68
Spring 1968
Summer 1968
Fall 1968
Winter 1968-69
Spring 1969
Average - last full year
Projected Average - based
on later modifications
Grate Size
3-1/2
Inches
6.0
6.8
6.9
7.7*
-
8.1*
9.2*
8.3
8.4
(opening between
5
Inches

-
7.8
8.0
7.6
6.8
-
7.4
9.0
bars)
6-1/4
Inches
8.4
7.0
7.9
8.1
-
-
-
7.7
9.4
* The opening between the bars was actually four inches.
                               2f

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                            TABLE  2

 Gondard Operating Production Rate Vs. Grate  Size - Tons Per Hour
                      (Operating Time Only)
Grate Size (opening between bars)
Period
Fall 1967
Winter 1967-68
Spring 1968
Summer 1968
Fall 1968
Winter 1968-69
Spring 1969
Average - last full year
Projected Average - based
on later modifications
3-1/2
Inches
6.8
7.0
7.1
8.0*
-
8.4*
9.7*
8.7
8.8
5 6-1/4
Inches Inches
9.3
7.3
8.2 8.1
8.2 8.4
7.9
7.2
-
7.7 8.1
9.3 9.7
* The opening  between the bars was  actually four inches,
                               22

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    Futhermore, the unit costs in Tables 3 and 4 are higher than would
be the case for a larger and differently designed plant because:
    1) Refuse is not conveyed to the mill as fast as the mill can grind;

    2) A similar plant without extensive foundations and extra conveyors
       would be less costly;


    3) A plant having proper haulaway equipment might be operated by
      two men, thereby reducing labor costs;

    4) Adaptations and improvements can still be made in haul away   operations.

    Land costs are not included because they are commonly omitted from
other studies, and because this plant was built on an existing city site
purchased many years ago.

    The costs per ton are calculated by divinding annual cost by the pro-
jected annual tonnage.  The annual tonnage is calculated by using the
"overall" production rate, the average number of operating hours per day,
and the number of operating weeks per year.  (See Appendix  B)

    Table 3 lists the cost per ton for each expense category for three
different size grates.

    Table 4 lists the same cost items which are adjusted on the basis
of more operating hours per day, and one less man.  It is assumed in Table
4 that the plant might be operated by two instead of three men for 7 hours
overall instead of the present 5.33 hours per day. These costs are not
further reduced for improved plant design.  The method used to compute
the costs listed below are described in Appendix  A.

    It was felt that transportation costs for this portion of the project
were unduly high and should not be used in projecting costs for future
installations.  Thus, "transportation" figure is not presented in Table
4, "Adjusted Cost Per Ton".

CRITIQUE OF PLANT OPERATIONS

    Besides the down tine attributable only to the milling operation (jams
of feccl conveyors and the mill), there were considerable periods of nonproducti
work.  In an attempt to quantify these nonproductive work times, the daily
recor-is from April 1 through November 29, 1960 were examined.  The average
number of minutes per day of nonproductive work are itemized as follows:
                               23

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                            TABLE 3

             Unadjusted  Cost Data For Gondard  Mill
                 (June  1968 Through May  1969)
Cost Item
Labor
Amortization
Power
Lighting
Water
Gas-heat
Hammer wear**
Mill Maintenance**
Small Equipment
General Supplies
Front End Loader
Operation
Transportation to
Landfill*r.
Other
TOTAL
Annual Cost
$39,800
$32,200
variable
$ 2,300
$ 200
$ 1,200
$1,600-1,710
$850-950
$ 800
$ 1,100
$ 500
$ 3,250
$ 1,700

3-1/2 Inch
10,750
$3.70
$2.99
.34
.21
.02
.11
.16
.08
.07
.10
.05
.30
.16
$8.29
ton
Grate Size
5 Inch 6-1/4 Inch
Annual Tonnage
11,500 12,050
$3.46
$2.80
.30
.20
.02
.10
.15
.08
.07
.10
.04
.28
.15
$7.75
ton
$3.30
$2.67
.30
.19
.02
.10
.14
.08
.07
.09
.04
.27
.14
$7.41
ton
 *Based on round trip of less than 1/2 mile.

**Annual cost  range reflects actual costs of  the three grate sizes,,

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                            TABLE 4

              Adjusted Cost Data For Gondard Mill
                 (June 1968 Through May  1969)
Cost Item
Labor
Amortization
Power**
Lighting
Water
Gas -heat
Hammer Wear**
Mill Maintenance**
Small Equipment
General Supplies
Front End Loader
Operation
Transportation to
Landfill*
Other
TOTAL

Annual Cost
$28,500
$32,100
$4,400-4,100
$ 2,300
$ 200
$ 1,200
$2,220-2,280
$1,100-1,250
$ 800
$ 1,100
$ 700
$ 3,250
$ 1,700


Grate Size
3-1/2 Inch 5 Inch
Annual Tonnage
14,100 15,100
$2.02
$2.28
.31
.16
.01
.09
.16
.08
.06
.08
.05
.30
.12
$5.72
ton
$1.89
$2.13
.28
.15
.01
.08
.15
.08
.05
.07
.05
.28
.11
$5.33
ton
6-1/4 Inch
15,800
$1.80
$2.04
.26
.15
.01
.08
.14
.08
.05
.07
.04
.27
.11
$5.10
ton
'*Based on round  trip of less than 1/2 mile.

**Annual cost  range reflects actual costs of the three grate sizes.

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    1.  Elapsed time betv/een arrival  of first load of refuse
        and start of milling                                 33 minutes
    2.  Conveyor and mill jams

    3.   Nonproductive time during milling:

             out of refuse
             truck breakdown
             lunch
             other
13 minutes
15 minutes
12 minutes
19 minutes
 4 minutes
    During the same period, there were 37 recorded cases of hammer
maintenance and 24 cases of general  maintenance which account for some
of the nonproductive work time listed above.

    Besides the nonproductive work times that were a part of daily
operation, there were also certain days that the plant was shut down.
A detailed tabulation of the dates,  reasons, and solutions for these
shutdowns appears in Appendix F.    Two things should be noted:  (1)
Many of the shutdowns could be eliminated through proper initial design
(this is something that is gained only by experience and is the purpose
of such a demonstration project); and (2) other shutdowns could be reducer
or eliminated by rearranging work schedules.
                                26

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III-B - Tollemache Operation

DESCRIPTION

    The Tollemache system consists of three basic elements: the
feed mechanism, the mill, and the takeaway mechanism for the ground
product.  Each has its own characteristics and each is equally important
in the normal daily operation of the plant, for if one system fails
the plant cannot function on a normal basis.  Following is a detailed
description of each portion of the system including description,
operation and operating problems.

TOLLEMACHE ELEVATING CONVEYOR

    The Tollenache mill is fed by an elevating metal flight conveyor
(Figure 8).  The one piece, 54-in.-wide, conveyor is driven by a 20 h.p.
motor equipped with a speed reducing mechanism and overload switch.  The
horizontal portion of the conveyor is considered the refuse storage area
and is nearly 18 ft. long (Figure 9 ).  The elevated portion is about 30 ft.
long and makes an anole of about 45* with the horizontal.  The speed
reducer or variable speed drive mechanism allows the operator to adjust the
conveyor speed from a minimum of 8 ft./min. to a maximum of 12 ft./min.
The automatic overload stops the feed conveyor when the mill motor draws power
25 percent above its rated capacity.  The conveyor restarts itself automati-
cally after the mill motor draws less than 80 percent of its rated capacity
for a 5 second period.

    The conveyor pit is 5 ft. deep and the walls range from 4.5 ft. at
the bottom to 12 ft. at the top.  At the point the conveyor leaves the
horizontal, the walls abruptly change to 4.5 ft. in width; thus, a
constriction is placed on refuse flow.  This constriction halts the forward
movement of the refuse mass and creates a tumbling or rolling action
which in theory should create an even feed to the mill (Figure 10).  An
even feed is a necessity for optimizing mill production.  Thus refuse
feeding is one of the most important functions in the overall mill
operation.

Feed Problems:

    In essence the type of feed being experienced in any one day
determines the production rate of the mill during that day.  If the
mill is to operate at its rated capacity, 15 tons/hr., 1 ton of refuse
must be transported to it eeery 4 min.  At the maximum speed of 10
ft./min. and assuming a refuse density of 350 Ibs./cu. yd. with a
refuse depth of 1 ft., it would take 3.5 min. to feed 1 ton to the mill.
This example is theoretical because refuse does not feed consistently
at a depth of 1 ft., nor is the density always 350 Ibs./cu. yd. or greater;
but it is evident that there is not much room for conveyor delays.
                                27

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    Experience with this conveyor at Madison has shown that excessive
loading of the conveyor bin is the prime cause of feed delays.  These
delays can consist of an empty belt moving toward the mill or periods
when the conveyor transports unprocessed material in slugs which in turn
overburden the mill motor causing the automatic-overload device to
activate.  Excessive loading of the bin causes refuse bridging near
the constriction where the conveyor leaves the horizontal.  Thus,
although the bin is full and the conveyor is moving, a very inconsistent
flow of material is being directed to the mill.  To overcome this problem the
mill operator only allows 12 cu. yd. of unprocessed material to be in
the bin at any one time.  The change has resulted in a much smoother
operation which has decreased feed delays; although the problem has not been
eliminated altogether.

Conveyor Maintenance and Breakdowns:

    Preventive maintenance on the conveyor is done once a week. During
this period the pulleys are greased and the tracks oiled.  A general
inspection to locate worn parts or potential trouble areas is also conducted
to minimize major breakdowns and to plan an effective repair program.

    The most serious breakdowns encountered in the use of this conveyor
have occurred when large metal objects in the refuse became lodged between
the conveyor rollers and track.  The problem, occurring three times in
1971-72, causes the rollers to jump the track resulting in severe damage to
the bin walls, conveyor flights, and belt tightners.  Although these
breakdowns are serious, they are not directly due to inadequacies in the
conveyor, but are a result of installing the conveyor inside the Gondard
bin conveyor as mentioned previously.  The problem centers where the
Tollemache conveyor makes its 180° turn at the center of the Gondard bin.
In the past, refuse was indiscrimately placed on the top of this area.
Thus, under the right circumstances it was possible for metal, etc. to
become lodged between the track and rollers.  To prevent this situation
an umbrella made of steel was constructed over the turn in early 1972,
thus preventing refuse from being placed in the area.  Since that time no
incidents similar to thosp previously described have occurred.

    Another problem that has caused concern is the speed reducer on the
conveyor motor.  There had been a high incidence of failure - on the
average, one every 3 months - of a linkage in the reducer assembly.
Although the linkages are not expensive, it is a nuisance to replace
them.  The problem was traced to excessive wear of the reducer assembly.
After an overhaul of this assembly such problems have been eliminated.

Overall Operation:

    Althounh there have been problem areas in the use of the conveyor
it is a substantial improvement over the system used in the fiondard operation.
The conveyor has field up satisfactorily under very severe conditions.
                                 31

-------
Most of the problems encountered can be eliminated by  modifications
to the conveyor itself or in its operation.   If must be remembered
that this equipment was not specifically designed  for  transportation
of refuse, but has been adapted to it.   With this  in mind,  the experience
gained becomes invaluable if applied to other installations.

TOLLEMACHE MILL

    The Tollemache Mill, shown in Figure 11, is a  vertical-shaft
ballistic-rejection hammer nill.  The mill  consists of funnel  shaped
outside v;alls and a somewhat inverted conical  rotor which  is  driven
by a 200 h.p. squirrel cane motor.

    Tbe outside walls consist of two layers  of metal.   The  outer layer
makes up the shell of the unit.  The inner layer,  crosshatched in the
figure, is a removable protective lining.  The rotor is made  up of
three sets of horizontal discs.  There are four discs  in the  first two
sets and five in the third.  Each disc in a  set has equal dimensions,
but the diameter of each set increases ftdm the top to the  bottom of
the mill, thus giving the rotor a conical shape.  Hammer tip  diameters
for the three sets are 33 in. at the top, 38 in. at the middle, and
43 in. at the bottom.  Six shafts are afixed,  vertically,  to  each set
of discs.  The 15-lb. hammers are mounted horizontally on  these shafts.
The 200 h.p. motor drives the rotor at 1350  r.p.m. and the  two are
connected by a rubber drive belt.  The motor is wired  to a  3-phase
440-volt power source.

    The funnel shape of the mill shell  (Figure 12 ) and somewhat conical
shape of the rotor act both to reduce motor loading and as  a  ballistic
rejection system.  Refuse is fed from the top right side (see Figure 11 )
and enters what is classified as the pre-break section of  the machine.
Here the material is initially broken up and sufficiently  reduced in
size in a semi-unconfined area, thus helping to reduce the  overall
loading on the mill motor.  Also it is in the pre-break section where
the ballistic rejection of damaging and unmillable material takes place.
A§ the material is being ground, it moves toward the neck  of  the mill.
At this location there are only between 3 and 6 in. of clearance; thus a
piece of material that is ungrindable or that has  not  be sufficiently
reduced in size to pass the restriction will be spun around the funnel
and will exit the mill via the reject chute which is located  opposite the
feed opening (not shown in Figure  11).  Thus the neck  section prevents serious
damage to the 1ower portion of the machine and also controls  particle size
to a limited degree.  Once the material passes the neck section, it  enters
what is called the grind section.  It is here where most of the work is
done.  The ground material is then discharged through  an 11 x 22.5  in.
opening at the bottom of the machine.
                                32

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Daily Operation:
    M
    Many factors arc related to the daily performance of the Tollemache
mill.  Some of these are the banner pattern used, hammer maintenance programs
that are followed, feed problems, breakdov;ns, etc.  These factors will be
discussed here with the exceptionoof problems related to feeding, discussed
above, and renovinn the around material, discussed later.

                           Hammer  Pattern

    Soon after installation, it was obvious that hammer pattern had a
definite influence on mill operation.  The original  pattern as used in
England and initially tried in Madison involved 54 hammers.  After a
short period of test runs it was evident that such a pattern did not
meet the objectives of milling for landfill disposal.  The end product
was more suitable to a composting operation, and the production rates
were very low.  Numerous modifications were then made, including reducing
the number of hammers to 32.  This hammer pattern is shown in Figure 12.
After the initial changes were made it was felt that further improvement
which would ultimately increase production and afford a smoother operation
was possible.  Therefore, during an extended test run, other variations
in the hammer pattern were evaluated.  The following is a compilation
of the changes made, reasons they were made, and an explanation of their
effectiveness.

    As stated previously, Figure 13 shows the pattern in use after the
initial reduction in hammers.  Stations 1  through 8 are considered the
pre-break section, stations 9 through 11 the grind section, and station
12 is the sweep section containing the exit hammers.  Stations consist
of a hammer and two spacers (3 through 11), three hammers and a spacer
(station 12), or three spacers (stations 1 and 2).  Vertical  shafts are
lettered and extend the length of four stations, as mentioned earlier.

    Daily observation soon showed that hammer 9E was experiencing more
wear than 9A or 9C, and needed replacing every two or three days.  The
reason is that 9E makes first contact with the material passing from
the neck.  To remedy the situation, all hammers in station 9 were put
on the same level.  Thus, excessive wear was distributed equally to
three hammers.

    Also receiving heavy wear were the undersides of the nine hammers
in station 12.  Accelerated v/ear in this area indicated that the
milled material was rolling too much before pushed onto the milled
refuse conveyor.  To alleviate this problem, the hammers and spacers
were interchanged.  Also, hammers in station 12 were moved to B, D,
F from A, n, F while hammers in stations 9, 10 and 11 were moved to
B, D, and F from A, C, and E.  Elimination of wear to the bottom of
the hammers in station 12 was accomplished, but a slinht increase in
wear to the top of these hammers v/as noticed.

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     Frequent jams of refuse just above station 1 were prevalent during
the first year of operation.  An attempt to eliminate these jams was
undertaken by placing hammers at 1C and IF and removing hammers at 3C
and 3F.  The two hammers in their new location help to pull the refuse
down through the feed chute.  This modification reduced the frequency
of jams.

     The final adjustment occurred when a hammer was placed in the lower
part of 8A and 8D.  Above the neck of the mill are six hammers in
station 7.  These hammers are placed so as to force any large ungrindable
object up through the reject chute thus preventing damage to the machine.
While keeping ungrindables above the neck, a restriction was also placed
on grinding material.  Therefore, two hammers were placed in section 8
to help pull the grindable refuse past the neck section.  This adjustment
has been worthwhile, since a slight increase in production and a smoother
operation have resulted.  Figure 14 shows the hammer pattern in use today
after the many modifications were made.

                    Routine Mill Maintenance

     Routine maintenance performed on the mill basically consists of
hardfacing and/or replacing hammers, shafts, and mill liners.  Other
areas of the machine, such as reject chute, rotor plates, cone liners,
etc., need only periodic attention which is not excessive in time or
money compared to the aforementioned items and thus will not be dwelt
upon here.

                       Hammer Maintenance

     Experience with the Gondard Mill had shown that a rigorously applied
program of hammer tipping significantly reduced hammer wear.  Therefore,
since the installation of the Tollemache mill, a similar but more intense
hammer maintenance program, has been in force.  This program consists of
an application of Arasco Super 20 hard-facing alloy to each hammer prior
to installation into the mill.  Hard surfacing, or tipping as it is called,
is applied to the wearing edges of the hammer.  Wearing edges are in
constant contact with the refuse and, consequently, deteriorate more
readily than other surfaces of the hammer (Figure 15).  Figure 16 shows
the dimensions of a typical hammer and the portions that are tipped.

     In addition to tipping all hammers before installation, 18 hammers
in the lower section of the mill are tipped daily.  These 18 hammers
do the most work and require constant maintenance.  The remaining 26
hammers in the pre-break section are inspected daily and tipped when
deemed necessary.

             Hammer Wear - Tipping vs.  Not Tipping

     On a full-scale operating basis, a set of 34 hammers maintained by
tipping will process 1000 to 1200 tons of refuse.  A set of untipped
hammers will process only 400 to 500 tons.  From this comparison it is
                               37

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obvious that tipping more than doubles hammer life; but it is not
evident that tipping is economical.  To study the economics of tipping,
a test was performed using tipped and nontipped hammers in the mill,
under normal plant operating conditions.  The comparison was made on a
cost/ton basis, and the results showed that a tipping program, if applied
rigorously, will save approximately 23 cents/ton over a program using
nontipped hammers.  The entire savings was due to the lower number of
hammers used in the tipping program.  Labor and welding materials for
the tipping program were about equal to labor for hammer changing alone
in the nontipped program.  A more complete and in-depth presentation
of the test is presented in Appendix G.

                          Mill Liners

     The hull or shell of the mill is protected by liners or wear plates.
The liners are made of a manganese steel alloy and are replaceable.

     For the first 2 years of operation no attempt was made to reduce
liner wear because the mill was run on a test basis and the liners
did not wear significantly.  A set of untipped liners was found to
last through approximately 12,000 tons of refuse.  In January 1972
the plant was put on a two-shift basis with the prospects of 45,000
tons of refuse being processed by the mill annually.  At that rate
of production four sets of liners would be needed each year.  At over
$1300 per set and with 32 man-hours of labor needed per change the
outlook was very expensive.  Consequently, methods of increasing liner
life were investigated.  The method first looked at was hardfacing.
At this point some difficulty was experienced, since a welding rod
made of an adequate hardfacing alloy that would deposit weld vertically
was needed.  After trying many types of rods, the Stoody 3/8 in. # 57159
proved to be the most efficient.  Liners are now extensively hardfaced
prior to installation.  They are also touched up in the machine when
excessive wear is noticed.
                       10-1/4
                                                            _t
    Figure 16.  Tollemache Hammer and Portions Tha  nrc r*"'-ip''-i

                               40

-------
    Tarly results indicate that this procedure has increased liner
life to 20,000 tons/set; this is almost double that of untreated wear
plates.  Other methods to increase liner life are now beinq studied,
such as rotating or inverting then periodically to evenly distribute
v/ear and weldinq nanqanese
netal itself.
                           rods to them to prevent wear of the base
Operational Aspects
                        Production Rates
    Mill production rate is a ratio of tons of refuse milled and
operating tine.  It is measured in tons/hr.  (TPH).  Two such rates
are usually computed; one using total running time, and the second
total running time plus down time.  Down time includes mill jams,
breakdowns, etc.  These rates are referred to as operational and
overall production rates, respectively.  The operational rate indicates
the efficiency at which the machinery is functioning and the overall
r-ite indicates the efficiency at which the plant is operating,  neither
rate takes into account routine maintenance or periods when no solid
waste is present to be fed into the mill.
    The Tollemache nil! is rated at an operational caoacity of 15 TPH.
On a daily basis these rates have ranged from 11 to 20 TPH.  On an average
it is near 1<1.  The overall production rate has been about 0.5 TPH
lover than the operational.
with a nininum of down tine.
                             This fact indicates that the machine operates
    A distinct seasonal variation in production rate has been noticed
at Madison which is related to the moisture content of the refuse.
During late spring, summer, and fall when the average moisture content
of the refuse ranges from 35 to 45 percent on a dry weight basis; the
highest production rates have been experienced.  In late fall and winter,
when noisture content is only 15 to 20 percent, production rates reach
a nininum.  This fact was brought out during two evaluations of the mill.
One was done during the summer and early fall of 1970.  The other during
the witter of 1971.  Table 5 shows a compilation of production rates on
a monthly basis for the tv/o test periods.  Monthly averaoe moisture
content is also indicated.

       The table shows that higher production rates were achieved during
periods of high moisture content.  Thus, when discussing mill production
rates, the figures should also be cited in dry tons of refuse per hour.
In this manner rates can be calculated for different applicatioss in other
                       For this reason, Table 6 is presented using dry tons
                     a production rate in dry tons/hr.  A comparison of
                     in Table h shows that the mill processes refuse at
                      and in fact the seasonal variations are due to
parts of the country
milled and conputinn
dry tons/hr.  (HTPII)
nearly the same rate
noisture content changes.
expressed both in TPH and
                           Because of this, production rates will  be
                          DTPH throughout the remainder of this report.
                                41

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                                TABLE 5

      Operating  and  Overall Production Rates for Tollemache Mill
July 6 to 31 ,
1970
August 1970
September 1970
October 1 to 9,
1970
July 6 to
October 9,
1970
February 4 to
28, 1971
March 1 to 31 ,
1971
February 4 to
March 31,
1971
Tons
Milled
1480
1573
1701
564
5318
1105
1519
2624
Time (Hours)
Operational Overall
100.4
104.9
122.5
38.0
355.8
86.40
118.11
204.51
104.0
107.7
125.3
38.3
375.3
87.06
121.61
208.67
Prod. Rate
Operational
14.72
15.01
13.89*
14.82
14.53
12.79
12.86
12.83
(TPH)
Overall
14.22
14.62
13.58*
14.72
14.18
12.69
12.50
12.58
Moisture
Content
Dry Weight
33%
35%
44%
32%
37%
25%
22%
23%
* During two periods  in September, linkage on the  variable speed drive of
  the mill  conveyor was broken.  Thus, the conveyor could only operate at
  its slowest speed.  This was a feed problem, not a mill deficiency.
                                   42

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                         TABLE  6

            Operating  and  Overall Production
                    (Dry Tons  Per Hour)

July 6 to 31, 1970
August 1970
September 1970
October 1 to 9, 1970
July 6 to October 9, 1970
February 4 to 29, 1971
March 1 to 31 , 1971
February 4 to March 31, 1971
Dry Tons
Milled
1110
1165
1180
425
3880
885
1245
2130
Production
Operating
11.05
11.11
9.64*
11.19
10.61
10.25
10.55
10.40
Rate - DTPH
Overal 1
10.67
10.82
9.43*
11.10
10.35
10.18
10.25
10.20
* During two periods  in  September, linkage on the variable
  speed drive of the  mill  conveyor was broken.  Thus, the
  conveyor could only operate at  its slowest speed.  This
  was a feed problem, not  a mill  deficiency.
                             43

-------
                    Power Consumption - Mi 1 1

    Mill power consumption is broken down into two distinct categories -
kilowatts (kv/) and kilowatt hours (KWH).  Kilowatts provide a measure
of peak demands for pov/er during a specific time period.  Kilowatt hours
are a measure of the actual energy use.  As such, kilowatts are not a function
of tons milled, but kilowatt hours ore.

    Mill demand ranges from 110 to 160 kw/mo.  The highest values are
experienced from November to 'larch; but since the cost of demand is
billed on the highest demand in the preceding 12 no. period the range
of demand is not important.  Energy use measured in kilowatt hrs./ton
(KUIi/T) follows much the same pattern peaking in the winter and reaching
lows during late sprinq, summer, and early fall.

    Extensive power data were kept during the two experimental evaluations
of the Tollemache mill.  Table 7 shows the summaries of data collected
during those periods.  Notice that energy use during the summer evaluation
was 2.5 KV/II/T lower than during the winter tests.  Also notice that on a dry
ton basis the summer  evaluation had a power consumption over 2.1 KWII/T
lower  than the winter test.  Thus, a definite relationship between KWH/T
and moisture content is not evident.

              Power Consumption - Mi 1 1 Accessories

    Mill accessories include the feed conveyor, final transfer conveyor,
stationary compactor, welding machine, etc., all of which operate from a
3-nhase 440-volt source.  Unfortunately, no equipment was available to
secure power data from the mill accessories on an individual basis until
January 1972, when a single pov/er meter was installed to record data from
the stationary compactor.  Prior to that time, all accessories had been
lumped tonether.  Data from both evaluations obtained has indicated that
pov/er consumption for mill accessories as a whole is about one-fourth
tiiat of the mill itself.  Power data obtained from the stationary packer
hookup itself will be discussed in the portion of the report dealing with
evaluation of a two-mill, two-shift operation.

                 ' 1i 1 1 Jams and '1_a_jp_r Breakdowns

    The mill itself is the most reliable piece of equipment in the
overall system,  nonetheless, the mill has not been completely trouble
free.  Some problems have included internal jamming, explosions, and
trouble with the radial and thrust bearing on the main shaft.

                         Internal Jams

    An internal mill jam differs from a feed jam in that it occurs in
the mill proper, usually in the grind section.  Such jams have occurred
when heavy wire, bed springs, tires, etc., inadvertently enter tho
machine.  When this hapnens the mill motor becomes overloaded a1^1
circuits arc broken.  The jams, especially when vrr^ ~;~ invol
operations for about an nour while the machine is h->ir: ci  .-
44
                                -

-------
                                 -7
                            TABLE 7
Comparison of Power  Data For Tollemache Mill Alone (1970-71)
Period I
July 6-31
August
September
October 1-9
Overall
Period II
February 4-28
March 1-31
KWH
10,672
9,856
10,288
3,152
33,968
10,272
12,864
Tons
Milled
1480
1573
1701
564
5318
1105
1519
KWH/Ton
7.20
6.26
6.04
5.59
6.37
9.30
8.46
Dry Tons
Milled
1110
1165
1180
425
3880
885
1245
KWH/
Dry Ton
9.60
8.46
8.70
7.42
8.75
11.60
10.31
Overall          23,136     2624       8.82      2130      10.86
                              45

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    During the first few months after the machine was installed,
these jams occurred about once a week.  Thus, elimination of this
problem became crucial.  Prevention has involved close scrutiny of
incoming refuse.  Any article deemed damaging or able to cause jams
is removed from the incoming stream of refuse on the storage floor.
This material is small in quantity.  It is landfilled separately, then
covered with the milled refuse.  Also, since Madison has a bulky item
pickup, refuse pickers are instructed not to collect potential damaging
articles.  The combination of minor separation at the plant and separation
on the collection routes has minimized internal jams to the point that,
on the average, only one is experienced a month.

                           Explosions

     As the refuse is being processed, a constant array of sparks
is being produced by contact of the hammers and metal in the refuse.
Therefore,  if a can of paint thinner,  unbroken bottle of alcohol, or
a container with any other flammable liquid happens to enter the mill
intact, an explosion is likely.   The explosions themselves do no notable
damage to the mill, but they are a potential hazard to personnel working
in the area.   During the 3 years of operation using the Tollemache mill,
only five or six such explosions have occurred.  After the first two
incidents,  an explosion chamber was constructed above the mill.  The
chamber consists of heavy steel chute leading from the top of the mill
to the plant roof.  Here the chute is capped with light sheet metal to
provide minimum resistance to rapidly expanding gases.   Experience has
shown that the explosion chamber functions quite well.

                         Bearing Problems

     By far the biggest concern in respect to the mill itself has been
the bearings that support the rotor.  Referring to Figure 11, notice
that at the extreme upper and lower parts of the rotor are three bearings.
The two similar bearings are radial bearings; the other is a thrust
bearing.  It has been the unfortunate experience at Madison to have
to replace two lower radial bearings and four thrust bearings.

     In the original design,  the thrust bearing was to draw the cooling
and lubrication oil from a reservoir and throw it up to the two radial
bearings.  About a year after installation, the thrust bearing burned
out and was promptly replaced.   The replacement bearing was manufactured
in the United States and was not exactly the same as the original manu-
factured in England.  Less than a week after replacement this new bearing
also burned out, as did a radial bearing.  At this time it was decided
that the new type bearing was not drawing enough oil to cool itself and
consequently not passing enough up to the radial bearings.  Thus, an oil
pump was installed to force-circulate oil to all bearings.  This worked well
until about a year later when the thrust bearing again needed replacement.
It was promptly replaced and burned out 3 mo. later, as did another radial
bearing.  At this point a careful reevaluation of what had taken place
over the last year and a half revealed the problem was not directlv
related to the circulation of oil but was the result cf *"-o -r*-v u'nat!.
moving up and down.  During replacement of the rotcr, :• : v,.:,- -J' nrovt.s <.-J


                                46

-------
that a retainer nut holding the rotor assembly together had v/orked
loose, thus allowing the entire rotor assembly to jump up and down
a fraction of an inch.  This resulted in abnormal stress on the
bearinns, and they burned out.  A key has been placed over the
retainer nut in the new assembly, and no bearing problems have been
experienced since that time.

STATIONARY COMPACTOR AMD TRANSFER TRAILERS

    Prior to installation of the Tollemache mill, continuous-cycling
refuse packer trucks were used to transport milled refuse totthe
landfill site.  The use of these trucks was inefficient in conjunction
with the less productive Hondard mill and proved to be even more so
with the more productive Tollemache mill.  It would take 20 to 30 min.
to fill a packer truck and 10 to 15 min. to empty one.  Therefore, one man
would constantly have to be watching and switching full trucks while
the mill was operating.  To free this man for other duties, and to
nrovide increased capacity for removal of milled material, a Heil
stationary compactor system was installed.

    The stationary compactor, similar to those used in transfer
stations, is used to compact the ground refuse into a 75-cu.-yd.
transfer trailer (figure 17).  A 35-cu.-yd. storage hopper was installed
above the compactor to allow the mill to operate while trailers are being
switched (Figure 18).  The storage hopper is outfitted with-an electric
eye that automatically turns off the feed conveyor to the mill if the bin
becomes full.  The electric eye eliminates spillage from the bin and
backups on the final transfer conveyor.

    Following are some of the characteristics of the compactor trailer
operation in conjunction with the Tollemache mill:
       1.  It takes 70 to
       2.  A full trailer
           milled refuse.
       3.  One can switch
       4.  Time to switch
               30 min. to fill one
               will net from 16 to
trailer.
20 tons of
               and empty trailers in five min,
               and empty trailers is about 20
where haul distance, round trip, is less than
The 35-cu.-yd. storage hopper provides enough
           mm.
           0.5 mi,
           volume
           to allow milling to continue while normal  switching
           of trailers take place.
       6.  The use of the compactor and trailers has  given one man
           an extra 50 to 60 nin. per trailer load for other duties
           around the plant.

Trouble Areas:

    Since thn plant is located on an operating landfill site, only
two trailers and one tractor were purchased.  The trailers are made
by the Heil  Company and consist of 75 cu. yd. of storage space, with
a hydraulicly operated ram to eject the milled refuse.  The hydraulic
                                47

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system is operated by an 80 h.p. motor affixed to the front of the
trailer.  The rear door is of the guillotine type for filling and has
a 360 h.p. gasoline engine.  The fact that the tractor has a gasoline
engine has caused some problems.  Mainly it does not have sufficient
torque at low speeds, thus making it hard to operate with a full trailer.
Some engine overheating difficulties have also plagued the tractor.  It
seems that the radiator gets completely plugged with dust, cutting off
circulation of air.  Constant maintenance on the radiator is needed to
keep it open and prevent engine damage.

    In ttie very near future Madison plans to transport the milled
material to other outlying landfills.  In anticipation of this plan,
it has acguired two new tractors and trailers.  The new trailers are
similar to the original ones except they have swinging gate rear doors
and their hydraulic system will he powered by the tractor itself.  The
new tractors are manufactured by Heil and contain 2'25 and 195 h.p. diesel
engines for over-the-road operation.

                      TOLLEMACME ECONOMICS

    As stated previously, two experimental runs using only the Tollemache
nil! were undertaken in summer 1970 and winter 1971.  During both of
these shakedowns, extensive cost data wero collected on labor, power,
repairs, replacement, etc.  Thus a comparison is possible between summer
and winter operations of the samo plant and equipment.  To make the comparison
equitable, channes in wages and otiier increases in cost betv/een the two runs
must be considered.  Therefore actual and adjusted cost will be presented
for the data obtained during 1970.  The adjusted cost will be computed
using the wages and prices in effect during the 1971 test.  All wage rates,
performance data, utility use, amortization data, and prices used in the
calculation of costs are presented in Appendices H, I, and J.

    Cost of the operation is best presented in tv/o general cateqories -
that of milling, to include conveyance of the unprocessed and milled
material; and that of transportation to the final disposal site, to
include trie stationary packer and hauling equipment.

IIILLLT. COSTS

    Table .1 contains an extension breakdown of the costs incurred during
the tv/o test periods on a per-ton basis.  Note that one must realize the
implications of expressing costs on a p^r-ton basis in order to use such
a finure properly.  Seriously affecting these figures are such uncontrollable
factors as:  1) The average moisture content of the refuse being processed;
?.} the characteristics of the refuse; 3) the type of material -
residential, commercial, industrial, or some combination of these; an.I 4)
geographical location of the plant.  Therefore the costs state'! here can !>;;
viev.-ec! only as an indicator of what was experienced at one  installation
and as such they cannot be expected to be generally applicable to other
locations.  A detailed analysis of the data presented in Appendices   H,
I ,   and   J, must be undertaken to determine to w^at -t r.;i.-> H'-jro-.
obtained at "'adison are valid for any similar install ;-r^,  I', A " M-'in-
considered.

                                50

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                            Table 8

                    Tollemache Milling Costs




Labor***
Depreciation (See Appendix H) •
Hammers & Shafts
Power
VJeldinn Pod
Plant Suppl ies
Front Fnd Loader Maintenance
'las - Heat
Lighting
Water ft Sev.'er
Contracted Repairs
Replacement Parts
Total
Test
Period #1*
Adjusted
$/Ton $/Ton
$2.395 $2.758
1.134 1.134
0.137 0.137
0.245 0.243
0.033 0.033
0.029 0.029
0.055 0.060
0.000 0.000
0.052 0.059
0.001 0.002
0.011 0.013
0.038 0.045
S4.130 $4.562
Test
Period #2**

$/Ton
$2.577
1.327
0.206
0.351
0.031
0.042
0.079
0.154
0.105
0.006
0.040
0.074
$4.992
**
***
14 wks. - July 6 - October 9, 1970, 5318 tons milled,  average -
          77 tons/day and 5.3 hrs.  machine time/day.

 o wks. - February * - March 31, 1971,  2684 tons milled,  average -
          66 tons/day and 5.1 hrs.  machine time/day.

 Includes all  fringe benefits. (See Appendices i and j)
    An analysis of Table 8 indicates that on an adjusted basis the cost
per ton for oeriod 1, summer 1970, is about $0.43 less than period 2,
i/inter 1971.  There are two prime factors contributing to this.  First
is the fact that on t!ie average less tons were milled per day during period
2; thus, relatively stable or fixed costs such as amortization increase on
a ner-ton basis.  The decrease in average milled tons per day is due to
seasonal variations in refuse quantities.  Also, during period 2 gas and
lighting costs increased due to changed weather conditions.

    The averane overall adjusted cost per ton of approximately $4.80 can
be misleading.  It must be remembered that this figure has been derived
from experimental  runs.  At the time of the tests the plant was only
operating at three-fourths of its rated capacity.  At full capacity the
plantccould average 90 to 100 tons/day as compared to the 65 to 75
experienced during the tests.  This would mean that fixed costs, labor
and amortization,  would be reduced by 23 percent to an average of $3.70/
ton.  This fact is borne out more clearly in following portions of this
report.
                                51

-------
STATIONARY PACKER AND HAUL COSTS

    Table 9 contains the detailed breakdown of costs  on a per-ton
basis for test periods 1 and 2.  The actual cost as well  as adjusted
cost per ton is presented for period 1  as in Table 8.
                            Table 9

                Stationary Packer and Haul  Costs
                  During Tollemache Evaluation
Test
Period T*

Depreciation (See Appendix H)S!
Labor (Driver)***
Power
Tractor ft Trailer Main-,enance
Packer Maintenance
Total
$/Ton
$0.488
0.120
0.016
0.018
0.010
$0.612
Adjusted
$/Ton
$0.448
0.137
0,019
0.027
0.012
$0.643
Test
Period 2**
$/Ton
$0.524
0.147
0.023
0.017
0.012
$0.723
*   14 Weeks in length - July 6 - October 9, 1970, 5318 tons milled,
                         average - 77 tons/day and 5.3 hrs. machine
                         time/day.

**   R Weeks in length - February 4 - '-larch 31, 1971, 2624 tons milled,
                         average - 66 tons/day and 5.1 hrs. machine
                         time/day.

*** Includes all fringe benefits. (See Appendices I and J).

    Again, packer and haul costs as shown are misleading and cannot be
assumed to reflect what would actually be expected under standard operating
conditions.  At full capacity, 90 to 100 tons/day, the overall average cost
per ton as indicated in Table 9 would be reduced by nearly 24 percent, from
$0.70/ton to approximately $0.53/ton.

    The costs of landfilling milled refuse are presented in Section III-D
of this volume.
                                 52

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Ill - C - Two-Mill, Two-Shift Operation

   As early as the summer of 1969, Madison was preparing to expand
the existinq physical plant and abtain additional  equipment in order
to operate on a two-shift basis and thus increase  production.  A plan
called for the city to achieve this goal by late 1971.   The first step
was taken in the winter of 1970-71 with completion of the plant expansion.
The second stop was completed with the conclusion  of tiie second and final
Tollenache evaluation in early 1971.  The third phase of the plan was
attained by December 1971 when a competent plant supervisor and three
additional men to man the second shift were hired.  Finally, in January
1972, the two-shift operation utilizing both the Gondard and Tollemache
mills was initiated.  The follovnng portion of this rcnort discusses
the gradual transition from a one-shift to two-shift operation, the
success and problems encountered, and the economics of increased plant
production from January 1 to June 30, 1972.

PLANT OPERATION

Description of Expanded Facilities:

   In the desiqn of the two-shift operation several important assumptions
were made:  1) the combined averaqe overall plant production would be
90 to 2? tons per hour and 2) the mills would be able to operate an
averaqe of 13 to 14 hours out of a 16-hour day.  Thus the design capacity
of the plant would be near 200 tons per day.  Assuming that a storage capacity
of 1.25 times the design capacity was needed, it became evident that the
original  plant with a storage of less than 100 tons was inadequate.  Therefore
the city undertook a $130,000 plant expansion.  Included in the expansion
was a special research area devoted to experimentation in paper recovery
that is not directly related to plant functions.  Therefore the net expense
devoted directly to daily plant operation was approximately $98,000.

     Figure 19 shows a floor plan of the original  facility overlaid by
that of the expanded facility.  An important thing to notice is that no
modifications were made to the mills or conveyor systems.  The plan indicates
that usable floor space was expanded from 6,650 sq. ft. to 13,150 sq. ft.
At an averaqe unprocessed stored refuse height of 16 ft. and density of
400 Ibs./cu. yd., the increased floor space would net a stored volume
equal to 310 tons vs. 85 tons for the original building.  Also included
in the expansion were a control room, office, conference room, and work-
shop (Figure 20).

     The control room, located on the second floor, is the heart of plant
operation.  It contains all systems controls and allows the operator a clear
view of the dump floor, both mills, their respective feed systems, and the
first portion of the milled refuse takeaway system.  ^ closed  circuit
television setup allows the operator to view the final  takeaway conveyor
and stationary compactor.  The office located adjacent to the control room
was provided for use by the plant supervisor.  The workshop is used as a
                                53

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tool room, storage room, and work area.   Located  below the control  room
is the scale room which was not modified during expansion.  The conference
room which was located on the second floor and is  used primarily for plant
tours.  It is not a necessary facility and could  have been eliminated
from the building design without hindering plant  operations.

Additional Equipment Requirements:

     Three pieces of equipment were acquired as a direct result of plant
expansion.  A new larger front-end loader was bought to handle the
increased volume of materials.  The new machine is a rubber tired 75M
model made by Michigan.  Bucket capacity is 3 cu. yd.  Also acquired was
a new Ford diesel tractor.  The new 225 h.p. tractor was needed to reduce
man hours devoted to clean-up.

Personnel Requirements:

     fiurinn the initial five years of operation,  three men were used to
perform all plant functions.  Supervision was provided on a limited basis
from the city's street department.  During evaluations of the Gondard and
Tollemache systems it was determined that three men were sufficient to
perform plant functions.  It was also learned that full-time supervision
was needed to create an efficient operation.  Thus, when preparations for
two shifts were made it was decided that three additional men would be
hired to man the night shift.  It was also decided to hire a full-time
supervisor.  It was assumed that the increase in  labor cost by the addition of
a seventy man would be offset by increased efficiency in plant operation.
This has Leen a valid assumption as indicated by  the economic data pre-
sented later in this report.

     The supervisor was carefully selected from a field of experienced
personnel and commenced work in August 1971, five months before conversion
to expanded operations.  During this period the supervisor became acquainted
with all plant functions and machinery and also developed procedures that
would be implemented under expanded plant operations.  The addition of
a plant supervisor has resulted in: 1) increased  plant production, 2) more
efficient use of man power, and 3) a remarkable improvement in plant clean-
liness and appearance.

Daily Operation:

     Table 10 shows the prescribed duty hours for each shift and the
supervisor.  Also included is the average time span for load arrivals
and average mill operating time.  The average length of a milling day is
10.5 hours (10:30 a.m. to 9:00 p.m.).
     Table 10 indicates that first shift hours are from 7:00 a.m. to
3:00 p.m. and second shift hours from 3:00 p.m. to 11:00 p.m.  The
supervisor's hours are 8:00 a.m. to 4:00 p.m.  Times of load arrivals
vary each day of the week but on the average encompass the hours of
9:00 a.m. and 3:00 p.m.  Mill start time is closely coordinated to load
arrivals but generally averages 10:30 a.m.  Hill  stoo time svoraqos
approximately 9:00 p.m.


                                 56

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                            Table  10

                Hourly Breakdown of Average  Day

               6 am     9        12 pm    3         6        9        11
First Shift
Second Shift
Supervisor
Load Arrivals
Million Tine
Preventive Maintenance Program:

     The hourly bar chart in Table 10 indicates a 3.5 hour peridd
between arrival of first shift personnel and mill start time.  This
tine is used for any necessary plant clean-up and also to conduct an
extensive preventive maintenance program.  The program consists of
equipment inspections, minor repairs, and any hard facing that needs
to be done.

     Detailed  inspections are performed on Mondays.  At this time
notes are taken as to what repairs or replacements are needed.  The
necessary work is then scheduled for completion during upcoming
weeks.  Necessary lubrication is also applied during Monday  inspections.
The mills are  inspected  and hammers tipped or replaced as necessary
on a daily basis.  Also, portions of the mill interior may be hard
faced if  needed.

Load Arrivals  and Mill Start Times:

     Packer  trucks deposit their loads  at the plant  over  a 6.5 hour
period.   However, the  trucks usually arrive  in bunches at three
specific  times durinn  that period - middle morning,  noon, and mid-
afternoon.   Thus  it  is not uncommon for ten  or twelve  trucks to be
lined  up  at  one  time waiting to enter  the plant.   A  union agreement
does  not.  allow packer  crews  to  start at staggered  times.  Another         _
factor  which contributes to  the problem is  a somewhat  odd plant floor  design
that will  permit only  two  trucks  to maneuver inside  the  plant at one time.
This  problem does not  affect nlant operations, but does  lower packer crew
efficiency   One benefit derived  from  the situation  is that  the front-
end  loader operator  does not have  a  continuous supply  of unprocessed
 refuse  to stack  or move, thus  allowing  him  free  time to  perform other
 duties.

      On on average  day,  5? loads  (190  tons)  are  handled  at  the plant,
 altiiouih  as  many as  72 loads (340 tons) per day  have been deposited.
 Those figures represent the  entire  city's  collection crews  and some
 private packers  (3  to 6 loads  per day).  In 1972,  approximately  46,000 tons
 were milled in the  two-mill, two-shift operation at  Madison.  It  is
 important to note here that all  residential  and  light commercial  refuse
 collected by city crews  is now being milled.  Bulky  items,  brush,  and
 bundled newspapers  are being collected separately andaare not milled.
 The bulky items  and brush are  landfilled separately, while  newspapers
 are recycle^.

-------
     Although It is not evident from the table, there is a definite
relationship between first load arrivals and mill start times.  The
basis of good mill operation is continuous material flow throughout
a day's operation.  Thus, mill start times must be planned to avoid
production stoppages due to a lack of material.  The plant supervisor
has made detailed investigations of load arrivals and mill start times
and determined that a lag of 1 1/2 hours beyond the first load arrival
will eliminate almost all production stoppages due to material shortages.

Overtime Requirements:

     Overtime performed by plant personnel has been primarily a result
of machine breakdowns; very few instances have occurred where milling
requirements have been a direct cause of overtime.  On the average,
15 man hours of overtime per week have been reported for the 7-man
crews.  Although not excessive, this time does appreciably add to
process costs since it is nonproductive.

'1111 Performance:

     Mill performance is measured by a combination of operating time,
down time, power consumotion, and daily tons of refuse milled.  In the
design of the two-shift operation it was assumed that an average of 280
tons of refuse could be processed per 13 to 14 mi 11-hour day at a plant
production rate of 20 to 22 tons per hour.  During the first 6 months
of 1972 an average of nearly 190 tons of refuse was processed per 10.4 mill'
hour day at a plant production rate of nearly 18 tons per hour.  These
figures are sonev/hat short of design but are nevertheless satisfactory
at this stage of operation.

     Two causes were responsible for the difference in the design and
actual figures.  First was the fact that during the initial 3 months
of oporntion, refuse generation was at its seasonal low.  Second, mill
downtime, near 2.8 hours per 10.4 hour operating day, was quite high.
Efforts are underway to increase available tonnage by increasing the
availability of privately collected refuse.  A concentrated effort is
beinq made by plant personnel to decrease the ration of down tine to
operating hours,  ''ore detailed data on plant performance is presented
below.

Production P%ates:

     As stated previously, production rates are a ratio of tons processed
and operating tine.  The rates are measured in tons per hour  (TPH).  Two
rates are computed for the fladison operation.  The first is named overall
production rate and is computed considering machine down tine in addition
to actual operating time.  The second - operational production rate -
is computed using only actual operating time.  The rates measure plant
and machine efficiency, respectively.
                                58

-------
     During experimental runs of both the Gondard and Tollemache mills,
operating and down times were recorded manually.  It was felt that this
method v/ould not be adequate under full-scale operation.  As a consequence
simple strip cnart recorders were installed to measure operatinq and down time
for each mill.  The recorders are equipped to record mill motor amperage on a
continuous running time chart.  Thus it is possible to determine machine
time above certain loadings.  At Madison, mill idle is the break point.
All times above this are productive, all below are considered down

     Since each mill has different rated capacities and the plant has
no means to record tons milled by each machine separately, it is
necessary to compute combined productive rates.  Plant efficiency is
computed by usinq the largest elapsed time recorded by either machine,
the reasoning beinq that even if only one mill is operatinq the entire
plant is functioning and this inefficiency should be reflected in plant
production rates.  Quite obviously in order to maximize plant production
rates, simultaneous mill operation must also be Maximized.

     An even mono complicated method is used to compute machine production
rates.  Aqain since both machines have different rated capacities it is
nocessan' to use an assumed combined design capacity.  The values used
arc P TPI! and 14 TPI1 for the Gondard and Tollemache mills respectively.
The combined figure is then 22 TPH.  Using each mill design capacity and
operatinq time, ideal tonnages are computed, added, and then compared to
actual total tonnaqe milled.  The ratio of actual milled tons to ideal
nille'i tons times the combined desiqn capacity gives the figure which
is designated machine production rate.  As can be seen this figure is a
numbericol value dependent on the assumed mill design capacities and as
such is not directly a real indication of how each machine is actually
performing; but it lias worked very well in depicting what production
rates might be expected if no down time is experienced during daily
operation.

     Table 11 presents a conpilation of C months of operating data for
the plant arid nills ^tiring 1972.  Included in the tabln on a month!v
basis are tons millo'l, plant operatinq time, overall and operational production,
refuse moisture content, and production rate on a day dry-ton basis.
Refuse moisture content as presented is computed on a refuse dry weight
basis.  Also included in this table aro production figures forttiie
second half of 1972, following the evaluation period.

     The data presented show a gradual increase  in plant tonnage as the
year progressed.  The increase is due to seasonal variations in refuse
generation.  On a daily basis, tons processed averaged a low of 125 in
January to a high of 254 during May.  Operating time quite naturally
also reflects this trend going from a low of 7.7 hrs. in January to a
high of 13.1 hours in May.  Down time increased with every month, peaking
in April and May at 77 hrs.  A ration of down time to operating time
indicates that March had a high of 0.39 hours of down time for every
hour of operation.  This figure was decreased to 0..25 by June.   Further
decreases in down time are needed in order to increase plant production
rates and overall operational efficiency.  Optimum plant operation would
be achieved when plant TPH is equal to machine TPH and this, of course,
can only be achieved when down time is reduced to zero.
                                59

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                               TABLE 11

           Operational and Overall Production Rates (1972)

                   (Two-Mill, Two-Shift Operation)
January
February
March
April
May
June

Overal1 for
January-
June 1972
Tons
Milled
2663
3334
3440
4236
5126
4518
Hours1
Plant
Time
161
205
208
235
262
232
Hours2 Overall3 Operational
Down Rate Rate
Time (TPH) (TPH)
26
39
74
77
77
57
16.51
16.28
16.51
18.04
19.57
19 48
17.93
17.93
20.00
21.98
22.86
22.24
Overall
% Moisture Dry Rate
Content Tons (Dry TPH)
23
23
25
29
40
38
2165
2710
2752
3287
3665
3276
13.44
13.22
13.24
14.00
14.00
14.15
     23317   1303   350    17.90
                         20.63
                               31
                               17855   13.71
July*
August
September
October**
November
December
      2165
      4947
      4797
      3040
      4840
      3483
Overal1 for
July-December
1972         23272
130
232
230
163
243
197
51
37
31
26
29
39
16.64
21.32
20.83
18.61
19.91
17.72
22.
23.
22.
20.
21.
AQ
17
44
16
74
             1195   213    19.47
19.23
                         21.72
Overall
1972
for
     46589   2498   563    18.65
                         21.22
* Low production because density tests conducted at landfill  diverted
  considerable unprocessed refuse.
**Low production because rotor was  being changed on Tollemache mill.

1.  Elapsed time from first mill start-up to last mill  shut-down including
    milling plus down time.
2.  Summation of hours down time for Gondard mill plus  Tollemache mill.
3.  Tons milled/hours milling plus  down time.
4.  Operating rate is defined by the following formula  for a  two mill
    facility, to take into account  the different milling capacities
    for the two mills:

     	(22 tons/hr) x Tons Milled	(
    (Tollemache operating hours x 14 tons/hr)+(Gondard  operating hours x 8 tons/hr;
                                     60

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     The data presented also show an increase in production rates
from January to June.  This is a result of improved plant operation
and also an increase in refuse moisture content.  Plant dry tons
per hour (DTPH) illustrates this very well.  The maximum variation
from the overall figure of 13.71 DTPH is only 0.49 while on plant
TPf! the maximum variation is 2.5  A better illustration is shown
in Figure 21.  In the figure, plant TPH and plant DTPH are plotted
versus time.  Also plotted is refuse moisture content on a dry
weiqht basis.  Notice how plant TPH follows moisture content very
closely while plant DTPH shows only a slight increase from March
to April.  This increase is more likely to be a result of improved
plant operation.

Power Consumption - Mills Combined:

     Mill power consumption is based on demand measured in kilowatts
((kw) and energy usage measured in kilowatt hours (kwh).  Demand is
related to instantaneous peak loadings and is not related to tons
processed.  Energy usage is based on machine running and to some extent on
machine running and to some extent on machine loading; thus it can be
related to tons as Kl-.'M/ton.  With the advent of combined mill operation
and with no means to record tonnage milled by each individual machine,
KUI'/ton will be discussed on a combined basis.  Power usane was recorded
by a 440-volt watt-hour meter installed on each mill during February 1972.

     From Table 12 it is evident that the Gondard machine created
more deman^ for power than the Tollemache mill in all months except
June.  It also should be stated that, the Gondard mill used nearly
as nuch energy as the Tollemache mill while only being rated at
53 percent the capacity of that mill.  Previous individual mill
evaluations back up these results.  The Gondard mill was reported to
consume power at the rate of 12.5 KWH/ton while the Tollemache mill
used only 7.?. KUH/ton on the average.  The combined overall KWH/ton
of 7.IP is better than thr> everage of either machine on previous
evaluations; but it should be stated that the data were collected in
1972 durinn n period which in the past has produced the lowers power
consumption recorded during a year.  On a dry-ton basis, the overall
combined figure was 9.61 KWH dry-ton.  No apparent relationship between
moisture content and power consumption seems to exist as in the case of
production rates.

Power Consumption - Mill Accessories Combined:

     For this evaluation, mill accessories included all conveyors
(feed and take away) and welding equipment, all of which operate from
a 440-volt power source.  The stationary compactor system will be cnm-
sidered later in this report.  Power consumption for accessories was
determined by taking the difference between the total 440-volt power
usage and that used by both mills combined.  Data obtained during tin's
evaluation indicated that on the average accessory demand is only 7 percent
of the total for both mills and that energy usage is 18 percent of the
total energy usage for both mills.  Thus mill accessories required
approximately 1.29 KUH/ton and 1.34 KWH/dry-ton of electical energy.

                              61

-------
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                                     62

-------
     The data in Table 11 also show an increase in production rates
from January to June.  Although this production rate increase
reflects improving plant operation, it is more directly related
to an increase in refuse moisture content.  Figures showing the
operational rates in terms of dry tons per hour (DTPH) illustrate
this dramatically.  The maximum variation from the overall figure
of 13.71 DTPH is only 0.49, while the maximum variation in
production rate (TPH) is 2.5.

     Power usage (KWH) was recorded by a 440-volt watt-hour meter
installed in February 1972 on each mill.  These figures are shown
in Table 12.
                            TABLE 12

           Power Consumption - Mills Combined  (1972)



                  Demand (kw)     Combined Energy    KWH     KWH
             Tollemache   Gondard   Usage (KWH)      Ton   Dry Ton

March           131         138       31,770        9.28    11.56

April           125         134       31,157        7.38     9.47

May             116         121       31,950        6.23     8.40

June            120         116       29,730        6.60     9.07

    Overall                                         7.19     9.61
                               63

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Stationary Compactor and Transfer Trailer Performance:

     With the simultaneous operation of both mills, an increase in
loading on the stationary compactor system has occurred.   The character-
istics of the compactor trailer operation revised from those in Section
III-B,  are:

           l) It takes only 45 to 60 min. to fill one 35  cu. yd.
              trailer.
           2) The 35-cu.-yd. storage hopper now does not  provide
              enough volume to allow milling to continue  while
              normal trailer svn'tching takes place.  The  mills
              in combined operation fill the bin in 2 to  5 min.
           3) This system now gives one man an extra 25 to 40
              min. for duties other than those related to milled
              refuse transportation.

Power Consumption:

     A watt-hour meter was also installed on the power source to the
stationary compactor in February 1972.  Unfortunately, adequate data
wore not obtained until April.  Table 13 contains a summary of power
requirements for the compactor system.

                            Table 13

        Power Consumption - Stationary Compactor (1972)

     Demand (KW)     Energy (KWH)     KWH/Ton    KWH/dry-ton

April    17.0           3423            0.81         1.04
May      15.5           3874            0.76         1.06
June     14.0           3265            0.72         1.00
    Overall                             0.76         1.03

     It is evident that the compactor requires less than  10 percent
of the power of the nills and their accessories.  The overall value
for the period of record was 0.76 KWI I/ton.  On a dry-ton  basis the
value increased to 1.03 KUH/dry-ton overall.

Operation Overview:

     An overview of the first 6 months of operation on a  two-shift
basis has revealed that the plant has not been hanpere
-------
under the present system a 12 to 13 hour milling day, at an average
18 to 19 TPH, yielding nearly 230 tons per day, would be more realistic.

     It also should be realized that this operation involves new personnel
and operating characteristics.  Thus it is fair to say that the system
was not operating to its fullest potential.  This is evidenced by the
increased amount of down time experienced during the two-shift operation
compared to down times experienced during single mill evaluations, as
citjpsd in other portions of this report.  Therefore it is realistic
to assume that mill production should increase to near 20 TPH on a
yearly average combined vn'th a 12 to 13 hour milling day; this v/ould
result in an average daily production of 240 tons or a yearly average
of r0,000 to 65,000 tons."

OPERATING COSTS

     Fxtensive cost data on all plant functions were collected from
January 1 to June 30, 1972.  Data collected will be presented under
tv.-o main divisions, namely that of milling costs and that of compaction
and final transportation..  Cost data will be expressed in terms of
total dollars expended and dollar cost per ton.

     As stated previously it is important to realize the implications
of expressing costs on a per-ton basis.  While such a figure is a
good indicator and presents a good means of comparison,  it can be
seriously affected by many uncontrollable factors such as: 1) the
average moisture content of the refuse being processed,  2) refuse char-
acteristics, 3) type of material - residential, commercial,  or industrial,
and 4) geographic location of the plant.  Therefore the cost per ton as
stated here can be viewed only as an indication of what  was  experienced
at the Madison installation.  Another reason why these figures cannot
be expected to be generally applicable to other locations is the diversity
of equipment used - most importantly, two vastly different mills.  The
data are presented to give an indication of how milling costs on a two
shift, increased-tonnage basis compared to costs on a one-shift basis.
Information on how costs are computed is presented in Appendices K,  L,
and M and should be consulted before attempts are made to interpret the
costs presented in this report.  A detailed section concerning cost
projections for a milling operation, utilizing the Tollemache mill only,
is presented in Section III-E of this report.

Mil lino Costs:

     The total cost of the u-nonth evaluation period will be discussed
first.  This will bo followed by descriptions of all pertinent cost
areas.  Table 14 contains a very detailed breakdown of the expenditures
and cost p^r ton for the period of record.  As stated previously total
tons mi lied 'luring that period were 23,317.

     The total b-nonth expenditure for mill operation was $91,001 or $3.90
nor ton.  f'otice that labor and depreciation account for $2.75, or 71
percent of that total.  Thus it is imperative to efficient operation
that the maximum tonnage of refuse be nil led during the 16-hour working

                               65

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                            Table 14
             Millinq Costs For Two-Mill, Two-Shift
             Operation (January throuqh June 197?)
Labor
Depreciation
Replacement Parts
Power
Hammers and Shafts
Heat-^as
Supplies
Liqhting
front-Did Loader Maintenance
Welding Rod
Contracted ^enairs
l.'ater and Sewer

                  Totals

* Based on 23,317 tons milled
                    Total  Cost
                     544,684
                      19,570
                       a,097
                       4,382
                       3,786
                       2,391
                       2,196
                       2,023
                       1,653
                       1,120
                       1,047
                          44

                     5591,001
               Cost/Ton*
                SI.912
                 0.838
                 0.346
                 0.138
                  .162
                  ,102
                 0.094
                 0.037
                 0.071
                 0.048
                 0.045
                 0.002
0.
0.
                $3.895
day.  If plant production could be increased from the current rate of
46,000 tons per year to a feasible 60,000 tons per year the total cost
of nil! ing could be reduced 15 percent to near S3.29 per ton.  This
is true because labor and depreciation are relatively fixed dollar
costs that are not directly dependent on tons milled as are parts,
hammers, etc.

     The final fiqure of 53.90 per ton as presented in Table 14
represents a sizable reduction from the earlier stated costs for
experimental runs of both the Gondard and Tollemache systems separately.
The fiqure is 48 percent lower than that actually experienced durinq the
Oondard evaluations of 1967, 1968, and 1969.  It is also 19 percent
lower than the averaqe fiqure obtained during the Tollemache evalua-
tions of 1970 and 1971.  The reduction is the result of betterssupervision
and the 125 percent averaqe daily increase in tonnaqe  milled over that of
the sinqle-shift operations.
Labor:

     Total millinq
6 months of record
labor costs as charqed
are shown in Table 15.
to the plant durinq the
     The total labor cost, $44,684, as shown in the table is based
on the averaqe annual hourly v/aqe including frinqe benefits as computed
in Appendix  K.   Averaqe annual hourly wage for plant personnel is
$6.993 and for the plant supervisor $6.254.  The supervisor's rate is
lower because he does not have longevity nor are there sic!  Inave and
vacation substitutes provided as with regular plant personnel.  "Hie
final figure is also based only on reqular hours worked.  T.ifi reason no
overtime hours are used is that they arc considered a frinqe benefit
and as such are us'.-d in computing the average annual hourlv vino.
                                 66

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                            Table 15

          Labor Costs - Two-Mill, Two-Shift Operation
                   (January through June 1972)

                         Regular Hours        Cost*     Cost/Ton**

Plant Personnel             5460            $38.180      $1.634
Supervision                 1040              6,504       0.278

           Total            C500            $44,684      $1,912

^Includes all frinqe benefits (See Appendix K.)
**Gased on 23,317 tons nilled.
     The workinq day of plant personnel can he divided into three
nain catenories:  1) nil!  operation, 2) repair maintenance, and
1} hammer maintenance,  "ill operation consists of all functions
pointer1 to daily mill inn such as nil! control, front-end loader
operation, clean-up, etc.   Repair naintenance is exactly what the
none relies, and hanner naintenance consists of tine devoted to
harinor tinpinn and channes.  The breakdown of mil linn labor costs
is shown in Table 16.  No  differentiation is made between the times
devoted, to the r.ondard or Tollemache system individually because
sufficient data of this sort appear in other portions of this report.

                            Table 16

                    Breakdown of Labor Costs
                 Two-Mill, Two-Shift Operation
                  (January through June 1972)

                           Man^Hours
                        Total      Per Week       Cost*      Cost/Ton**

Mill nnorf,tion           3969       152.6        $27,754      $1.138
Repair ''aintenance        850        32.7          5,944       0.254
Manner Maintenance        641        24.7          4,482       0.192
      Subtotal           5460       210.0        138,180      $1.634
Supervision              1040        40.0          6.504       0.278
        Total            6500       250.0        $44,604      SI. 912

*Includes all frinqe benefits
**P,ased on 23,317 tons milled.
                                 67

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     The data clearly indicate that alnost 73 percent of the  total
labor cost, not including supervisor, is a result of mill operations,
while only 15 percent and 12 percent is the result of repair  and
hammer maintenance, respectively.

Depreciation:

     Complete depreciation data for the milling system are presented
in Appendix  L.   Based on the data available, the total cost for  the
entire 6-month period was S19.570.  On a per-ton basis the figure  is
SO.338.

Power:

     Pov/er costs for the two mills combined are presented in  Table  17
on a monthly basis.  Table IP contains data on mill accessories.   A
detailed breakdown of current power and utility rates is available  in
Appendix  M.   Demand or energy usage has been discussed earlier in
this report.

                            Table 17

       Power Costs, 'lills, Two-Mill, Two-Shift Operation
                  (January through June 1972)
                Dena nd
                 Cost

January         S  341
February           341
March              341
Apri1              341
May                341
June               341
     Overall    S2.04P
            Energy
             Cost

            $  257
               311
               332
               329
               330
               321
Total
 Cost

$  598
   652
   673
   670
   671
   662
S3,926
                                                     Cost/Ton*
                                                      $0.
                                                      0.
                                                      0,
                                                      0.
                                                      0.
                           225
                           19r>
                           196
                           15P
                           131
                                                      0.146
                                                      SO.ICO
                            Table  18

  Pov/er Costs, Mill Accessories, Two-Mill, Two-Shift Operation
                   (January through June 1972)
February
'•larch
Apri 1
''ay
Juno
             1
Demand
 Cost
                $
                  I'.1
                  19
                  10
                  1°
                  IP
       or; 21,317 tons m"!le<
Energy
Cost

$ 47
 56
 60
 60
 f.l
 GF.
                                 68
                                         Total
                                         Cost
                                                    Cost/Ton*January

                                                      $ 0.025

-------
     In both tables demand is constant and in the case of the mills
the demand charqe costs more than the energy used.  This is an important
factor in the overall power cost, as an increase in tonnage nil led will
decrease the total cost per ton.  For example, during the Tollemache
shakedowns, power averaged $0.24 per ton at an average rate of 70 tons
of refuse milled per day.  Power costs for the Gondard shakedowns
averaged about $0.28 per ton back in 1968, at much lower rates, on the
average of 46 tons of refuse milled per day.  During 1972 the combined
mill operation consumed power at the cost of $0.168 per ton, or a 53
nercent reduction over the single-mill operation.  The reason for the
decrease is that 187 tons of refuse were processed ner day in 1972.

220-Volt Service - Lighting:

     Lighting and other small services are supplied by 220 volt service.
Table 19 contains monthly 220-volt service costs and electricity used.

                            Table 19

         Lighting Costs, Two-Mill, Two-Shift Operation
                  (January through June 1972)
             Demand
              (kw)
Energy
 (KVJH)
.January
February
'•larch
May
Juno
Overal1
38.6
40.0
40.0
40.0
40.0
40.0
18,788
17,088
19,286
14,734
1?,772
13,294
Demand
 Cost

 $58
  61
  61
  61
  61
  61
1361
                                     Energy
                                      Cost
Total
 Cost
Cost/Ton*
$31?
293
326
258
228
236
$377
354
387
319
289
2'37
$0.141
0.106
0.113
0.075
0.056
0/066
                                           1,660
                                       $0.0?6
*P.nserl on .71,317 tons milled.

Heat - ras:

     The plant is heated bv radiant natural gas heaters.  Table 20
contains a monthly breakdown of heating costs.  The total expenditure
reflects three months of winter heating bills and three months of much
lower sprinn bills.  Past experience hnr. shown that heatinn costs have
none almost to zero from June throunh September.

'•ator .ind Sewer:

     Total  water usane equaled 6510 cu. ft.  Cost of tin's water equaled
$?1.00.  Sc^er c'tarqes are 141"1 percent of the tot?! water cost.  Tnus
the water and sewer bill for C> months equalled $44.45, or $0.002 ner ton,
                                69

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                            Table 20

       Plant Heating Costs, Two-Mill, Two-Shift Operation
                  (January through June 1972)

                  Usage
            100 Cu. Ft. Gas          Cost         Cost/Ton*

January          8,679             $  823          $ 0.309
February         0,297                788            0.262
March            5,124                468            0.136
April            1,983                194            0.046
May                618                 63            0.012
June               540                 55            0.012
      Overall                      S2.391          $ 0.102

*Cascd on 23,317 tons milled.

Supplies - Hammer Maintenance Program:

     Items such as hammers, hammer shafts, and welding rods constitute
supplies used in the hammer maintenance program.  Table 21 contains
all pertinent data in respect to number of each item used and resultant
expenditure.

                            Table 21

Supply Costs, Hammer Maintenance, Two-Mill, Two-Shift Operation
                  (January through June 1972)
                Used

Hammers         1000
Shafts            43
Welding Rod
     (Ibs.)      600        1.88      1.128      0.048
  Overall                            $4,914     SO.210

*Based on 23,317 tons m'lled.

     The total cost of hammer maintenance supplies was $4,914, or tae
fourth laronst expenditure in eespect to plant operation.  It would
be expected that the rn.21 $or ton would remain relatively constant
if changes in flaily tonnage milled were to occur.

Replacement Parts:

     As indicated in Table 14, cost of replacement parts was over .1C,000
$0.35 per ton, anr! is the third most expensive item on the list.  Parts,
replaced durina the period of record were mill grates (^ondard) and wear
plates (Tol leniache) as well as conveyor belting - all of ',;:;ich arc very
expensive items.  ." set of Tolleriache liners, which last approximately
6 months, costs nearly $1,300.  fiondard grates also lastinn 6 months cost
                                70
Unit
Cost
$ 3.27
12.00
Total
Cost
$3,270
516
Cost/Ton*
$0.140
0.022

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nearly $800 per set.  Other parts such as small motors, conveyor
slats, bearing, etc. make up the remainder of the expenditure in
this area.

Other Expenses:

     Other expenses include miscellaneous supplies, contracted
repairs, and front-end loader maintenance.  Supplies consist of
janitorial requirements, office materials, grease and oils, etc.
The total expenditure for supplies, $2,196, costs almost $0.10
per ton.  Contracted repairs include all labor and material charges.
for repairs made by outside concerns.  The total cost, $1,047, 1s
less than $0.05 per ton.  Front-end loader maintenance 1s dependent
on the hours of vehicle use.  The city garage charges $4.27 per hour
to cover vehicle aaintenance such as oil, minor repairs, grease, etc.

Stationary Compaction and Haul Costs:

     Expenses for compaction and hauling include labor, depreciation,
power, and equipment maintenance.  Not included are very small
expenses due to heat, lighting, and water v/hich are grouped under
millinq costs.  Table 22 gives a complete listing of all expenses
attributed to final handling of the milled material.

                            Table 22

Stationary Compaction and Haul Costs, Two-Mill, Two Shift Operation
                   (January through June 1972)

                                    Cost      Cost/Ton*
Labor                             $5,216      $0.223
Depreciation                       4,380       0.188
Compactor Maintenance                753       0.032
Haul-Vehicle Maintenance             597       0.025
Bower                                334       0.014
           Overal1               $11,280      50.482

*i!nsed nn 23,317 tons milled.

     Labor expenses, as "ras the case with milling costs, constitute the
largest expenditure.  ," total of 780 hours, or 30 man hours per v.'eek,
-..'as spent in transporting milled material to the landfill, (-.ound trip-
is loss than 1/2 mile.)  Peprociation charges are computed in Appendix
L   and include the compactor and all haul equipment.  Vehicle maintenance
is computed on a per-mile charge.  Tractors are charged at a rate of
!">0.2fi per mile and transfer trailers at the rate of $0.25 per mile.  Charges
cover all oils, grease, and minor repairs.
                                71

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     Pov/er usage was presented in Table 13 and need not be stated aqain.
Table 22 indicates that the total power cost is almost insignificant at
$0.014 per ton.  Compactor maintenance at $0.032 per ton consists of
labor and parts for all repairs to the compactor.  As the figures show,
the compactor is not prone to breakdowns.
                                                                                       V
                                                                                       *
                                72

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III-D - operational Cost Of Landfill inn Milled Refuse

    The original Inndard project investigations included an initial
exanination of tiie operational costs of landfillinn milled refuse.
These data v/ere United to the extent that the evaluations were made on
the basis of landfill inn only 40 to 60 tons of milled refuse per day.

    Hith the advent of the double shift operation and the subsequent
nil!inn of an average of more than 180 tons of refuse per day, better
data on landfillings costs becane available.  As a result, extensive
records of landfill costs were kept during the period of January 1 to
June 30, 1972.  These data have been reduced and are presented in tht
followinn portions of the report.

    Cost data will be presented in two forms.  The first will be a
detailed explanation of expenses incurred and second will be a comparison
of two separate landfill operations—one milled, the second unprocessed;
both are operated by the City of Madison.

LAflDFILLIFIfi COSTS USING MILLED UNCOVERED REFUSE

    Located only one-quarter nile from Madison's refuse reduction plant
is the Olin Avenue landfill site.  Originally a swamp, the area was first
used as an open burning dump in the late 1940's.  During the early 1960's
the area was converted to a sanitary landfill.  In 1966 the solid waste
reduction plant was installed on a small portion of city land adjacent
to the fill.  From 1966 until 1971  the landfill site was used as a test
area for comparing the degradation of milled uncovered refuse and un-
ppocessed covered refuse.  Normal sanitary landfilling also took place at
the site.  In mid-1971 the area was completely converted to a landfill
for milled refuse to which no daily cover was applied.  At this time only
one niece of machinery was regularly used at the site.

    When the conversion to a two-shift operation was completed in
January 1972, no drastic changes in the operation took place.  It was
felt that the Trash Pak on the site was adequate to handle the increased
volume of material.  To date this has been true.  There is no problem in
fiandlinn the 180-ton-per-da.y average of milled refuse, and indications
are that the present one-machine operation could handle 300 tons on a
daily basis.  :,'o attempt will be made here to describe the physical aspects
of landfilling milled solid wastes, as adequate data exist in other
portions of this report.

Total  ^peratinn Cost:

     The total cost of operating the Olin Avenue landfill includes expenditure
for labor, supervision, depreciation, cleanup, equipment maintenance, etc.
Table 23 contains all data collected in respect to expenditures at the Olin
Avenue milled refuse site from January 1 to June 30, 1972.  The data will
be  followed by explanations of each category used in the table.  No charge
                                73

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for land is included because the land has been owned by the City for
an extended period of tine.  It should be noted that land costs are
regularly omitted from similar reports.  Also not included is a cost
for cover dirt (none v/as used) because the idea behind milled refuse
landfill operations is the elimination of daily cover dirt requirements,
althounh it is recognized that cover should" be applied at certain tines
throughout the year depending on local conditions.
                             TABLE 23

          Landfill Costs Using Milled Uncovered Refuse
                  (January through June 1972)
                                          Cost
                                       $ 7,290
                                         2,143
                                         6,363
                                           223
                                       516,019
                                       $ 4,825
                                           717
                                           818
                                       $ 6,360
                                       $   435
                                           420
                                       S   855
                                       523,234
Cost/Ton**

$ 0.312
  0.092
  0.272
  0.010
S 0,686
Wages*
  Compaction
  Supervision
  Cleanup
  Auxiliary Operation
        Subtotal

Equipment
  Permanent
  Auxiliary
  Depreciation (Permanent)
        Subtotal

Materials - Area Improvement
  Stone
  Road Oil
        Subtotal
                 Total

*Includes all fringe benefits.
**Based on 23,317 tons milled.

    The f.-month landfill operation cost the city $23,234, while 23,317
tons of refuse were disposed.  This represents a ner-ton expenditure of
only ^0.994.

                             !|ages

    Hy far the largest cost of the landfill ooeration was that for labor.
The fill is manned by one full-time compactor operator.  The operator
averages C iiours on the fill and 2 hours for enuipnent maintenance.  Total
overtime for the 6-months period was 20 hours—less than one hour nor ,,-c.v1'.
The operator works from 7:30 a.m. until 4:00 p.m.  Ml material r;rocesse,'
after 4:00 p.m. is stockpiled on the fill to be pushed and compacted the
following morning.
$ 0.686
  0.030
  0.035
S 0.272
$ 0.019
  0.018
S 0.037
"5~ 0.994"
                                74

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     There were no difficulties in hand!inn the average daily loading
of over 1 no tons.  There is even a belief that an averaqe of 300 tons
per day could be handled routinely.  This is possible because it takes
only 15 to 20 m'nutes to spread and compact a load of milled material.
This represents a minimum of 3 loads per hour that could be handled.
At 6 machine operatinq hours per day and an averaqe of 15 tons of milled
nateriral per trailer load, a minimum of 270 tons of a maximum of 360 tons
of milled material per day could be placed and compacted.  At present
there is a 45 to 60 minute lag between each load of milled refuse; thus
the operator has nearly 30 minutes per hour when no milled refuse is
available for compaction.  This time is used in further compacting in-
place refuse, but could be used to handle more material as mentioned
above.  Another fact that should be mentioned is that it takes only
about one hour to spread and compact the 45 to 100 tons of milled refuse
left each ninht after the operator leaves for the day.

     The second larqest labor expenditure was for area cleanup.  Cleanup
consists of paper pickup, qrass cuttinq, etc.  Cleanup averaged 184 man
hours ner month.

     Supervision is provided by riadison Street Department foreman.  The
supervisor averages about 2 hours per day at the site.

     An auxiliary operator spent 32 hours at the landfill site during
the six-months period on repair to the access road.

                           Equipment

     Permanent equipment includes a steel-wheeled compactor, which has
proven verv effective on milled material.  It is operated between 5 and
7 hours per day.  Charnes are based on hours used.  The City garane sets
the hourly rate at 
-------
                                                                                   	""~  r~
operation handled about two times the volume of material that was handled
at the Olin Avenue site during the period of record, January through
June of 1972.

     The data as presented in Table 24 reveal that the City of Madison
expends, on a per-ton basis, over three times the amount of money to
landfill unprocessed refuse as it spends to landfill milled refuse.
A further breakdown of the data shows that the City spends 2.8 times
more money on wages and 3.6 times more money on equipment for conven-
tional sanitary landfilling versus landfilling of milled refuse.  It
should be noted that the substantially higher cost of conventional
landfilling as experienced in Madison is primarily due to the handling
of cover dirt.

                               Table 24

                         Cost Comparison -
             Milled Versus Unprocessed Refuse Landfills
                    (January through June 1972)
                                                Olin         Truax
                                               $/Ton         $/Ton
Wages*
   Compaction                                 $0.312        $0.449
   Supervision                                 0.092         0.229
   Caretakers                                    -           0.374
   Paper pickup                                0.272         0.222
   Loading (dirt)  .                              -           0.182
   Hauling (dirt)                                -           0.335
   Road repair                                 0.010         0.01.0
   Scale operation                               -           0.121
             Subtotal                         $0.686        $1.922
Equipment
   Compaction
   Loading (dirt)
   Hauling (dirt)
   Paper pickup
   Road repair
   Misc. maintenance charges
   Depreciation
             Subtotal

Materials - Area Improvement
   Stone
   Road Oil
             Subtotal

                Total
$0.206
 0.020
 0.01.0

 0.035
$0.271
$0.019
 0.018
$0.037
$1.922
 0.209
 0.211
 0.015
 0.008
 0.076
 0.105
$1.073
              $2.995
*Includes all fringe benefits
                                  76

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         IV.  CHARACTERISTICS OF MILLED REFUSE

IV-A - Particle Size and Density
      This section discusses a study of particle sizes of milled muni-
cipal refuse as well as the results of compressibility tests on milled
and unprocessed municipal refuse.

      Sieving was found to be a suitable method for determining
the particle size distribution of milled refuse.  It was found that
80 to 90 percent of the particles on a dry weight basis passed through
a 2-in. screen, and 15 to 30 percent passed through a 0.2-in. screen.
The study also showed that refuse shredded with either the Gondard
or Tollemache hammer mills,  as operated in Madison, has approxi-
mately the same particle size distribution. Increased moisture content
of refuse was found to result in a more finely ground product, whereas
an increase in hammer wear was found to result in a more coarsely
ground product, in the case of the Tollemache mill.

      The compressibility tests on milled and unprocessed refuse
showed densities approaching asymptotic values with increasing
pressure. The densities of all test samples increased when vibrations
were applied during compression; the increased densities varied
directly with the amplitude of the vibrations.  The resulting densities
ranged from 1,510 (no vibrations) to 1,750 Ibs./cu.yd.  (with vibra-
tions) for milled refuse at  80 psi pressure and  13,05 to 1,495 Ibs./cu.yd,
for unprocessed refuse at the same pressure. At the pressure and
level of vibrations comparable to landfills compacted with a D-7
Caterpillar tractor, the density of milled refuse was 950 Ibs./cu.yd.
and that of similar but unprocessed  refuse was 660 Ibs./cu.yd.

      Tests showed that the reduction in density due to springback
after the pressure was released was about the same for both milled
and unprocessed refuse—about 22 percent. A  reduction in density
of about 4.3 percent in the case of milled refuse and 9.1 percent
in the case of unprocessed refuse samples was  measured as a result
of bridging along the sides of the container used in this study.
                               77

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                        PARTICLE  SIZE

EXPERIMENTAL PROCEDURE

      Several possible techniques for determining particle size
distribution in milled refuse were evaluated in preliminary tests,
including direct measurement, sedimentation, and sieving.  For
this study, sieving was selected. Hand sieving, instead of mechanical
shaking, was  used to provide the variety of motions necessary to
get milled refuse particles through the sieves.

      Thirteen sieves of different mesh sizes  (Table 25 ) were
used for particle size analysis of milled refuse. A bottom pan was
used to collect the sample passing through the finest screen, while
a top lid contained the sample on the coarsest screen while shaking.

      About 200 gms. of milled refuse were taken from a freshly
collected refuse sample of about 7 Ibs.  It was spread in two glass
pans and covered with aluminum foil.  While drying, water vapor
escaped through holes in the foil. The drying lasted from 18 to
24 hrs. in an oven with forced air circulation,  at 100° C .  After
drying, the sample was cooled for 1 hr. in a large desiccator.
Approximately 60 to 100 gms. of dry sample was then taken and
weighed accurately to 0.1 gms.

      The accurately weighed sample was used for sieving analysis.
The sample  was put on a 2-in. wire mesh sieve with a pan below
and a lid on top.  The particles passing through the mesh during
shaking were  collected in the pan.  The weight of particles passing
through the first sieve was recorded.

      Particles passing through  the 2-in. sieve were next placed
on the 1-in. sieve and the shaking procedure repeated.  This process
was continued for  each sieve in sequence. The percent of solids
retained and passed through each sieve was calculated, based on
the original dry weight of the sample.

      Another possible method of analyzing particle size of milled
refuse is direct measurement with a ruler.  To compare the two
methods , and  to check the reliability of the sieving procedure, a
100-gm. sample of dry milled refuse was taken and analyzed by
sieving. Then another sample was taken from the same source and
analyzed by measuring individual particle size with a ruler.
                               78

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                          TABLE  25

                        Standard Sieves

Sr.
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
U.S. Standard



U.S.
U.S.
U.S.
U.S.
U.S.
U.S.
U.S.
U.S.
U.S.
U.S.
2"
1"
r
3
4
6
8
12
16
20
50
100
120
Size of Mesh
(inch)
2"
1"
i"
0.263"
0.185"
0.131"
0.093"
0.065"
0.04G"
0.0328"
0.0116"
0.0059"
0.0049"
Size of Mesh
(mm)
50.8
25.4
12.7
6.68
4.7
3.34
2.362
1.650
1.242
0.833
0.295
0.149
0.124
      The sample for direct measurement consisted of about 40 gms,
of dried milled refuse.  This sample was weighed accurately and
placed on a larf;e piece of paper.  The largest dimension of each
particle was measured with a ruler.  Particles of similar size were
kept in separate piles which were later weighed to calculate the
percentage of that size, based on the original dry weight of the
sample.
                              79

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      Figure 22  shows the results plotted as the size of mesh on
a log scale vs. the percentage finer than the size shown on the ordinate.
This figure shows that 97 percent of the particles were finer than
5 in. according to direct measurement, but finer than 2 in. accord-
ing to the sieving test. Obviously, some particles larger than a
given mesh size can pass through a screen along with smaller particles.

      The curves become almost identical for the particles less
than about 0.5 in., so the error in sieving appears most striking
among the large particles. Although it is probably the only truly
accurate method of determining particle sizes, the direct measurement
method is time consuming. Therefore, even though these data showed
some discrepancy between the two methods, sieving was the method
chosen for the remainder of this study.
SPECIFIC TEST PROCEDURES , RESULTS , AND DISCUSSION

Moisture Content vs . Grinding:

      The effect of moisture content on the particle size of milled
refuse was determined by changing the moisture content of refuse
during a special test sequence. On November 8, 1971, unprocessed
municipal refuse taken from a huge pile was divided into three piles,
each weighing approximately 500 Ibs.  A front-end loader was first
weighed with the bucket empty and then filled with refuse. After
weighing, the piles were designated A, B , and C .

      Pile 'A' contained 560 Ibs. of refuse, and no water was added
to it.  Pile 'B1 contained 460 Ibs. of refuse, and approximately 69
Ibs. (31.4 liters) of water was sprinkled on the surface, while mixing
with shovels, to increase the moisture content.  Pile 'C' contained
480 Ibs. of refuse and approximately 144 Ibs.  (65.5 liters) of water
was applied as above. Each pile was mixed again, and then covered
with a large polyethylene sheet to minimize loss of water during
storage overnight.

      The following morning each pile was mixed again before being
ground.  Refuse from pile 'A1 was dumped into the feed bin and
grinding was carried out with the Tollemache mill. Three samples,
each containing  about 5 to 7 Ibs., were collected in separate bags,
tied securely, and labeled.
                               80

-------
      A similar procedure was carried out with pile 'B1 and 'C1.
Care was taken while milling not to mix the sample from one pile
with that of another.  All bags were carried to the laboratory for
analysis.  Each sample was analyzed for moisture content and particle
size.  To determine moisture content, the refuse was placed in glass
pans , spread evenly, and covered with aluminum foil.  The pans
were dried to constant weight at 100° C. (usually  overnight) , cooled
in a desiccator, and again weighed accurately.
      Percent Moisture Content = Loss in wt. x 100
                                   Dry wt.
Results and Discussion:
      The samples of milled refuse from the three piles had a moisture
content of 46 .3,  66.2, and 91.5 percent on a dry weight basis ,  re-
spectively .  As the piles contained the refuse of November 8 only,
the average composition of refuse in each pile could be expected
to be similar.  Also, since all three piles were ground within 2 hrs.,
under similar  operating conditions ,  it was expected that there would
be no effect on particle size  due to hammer wear or feeding rate
variations.  Thus , by keeping all  controllable conditions similar,
the only variable affecting particle size could be expected to be
the moisture content of the refuse.  Figure 23  shows the particle
size distribution curves following  triplicate analyses.

      A statistical analysis led to the conclusion that the moisture
content of refuse may be expected  to affect the particle sizes of refuse
as milled with the Tollemache mill, with increasing moisture improving
the grinding.  This conclusion is true for the refuse under study
and only for particle sizes larger than 0.2 in. For smaller particles,
the moisture content has little effect on the particle size.  This  may
be expected as particles of this range include dirt, glass,  ceramics,
etc., on which moisture content would have little or no effect.
Hammer Wear vs . Grinding:

      Hammer wear is thought to affect the particle size of milled
refuse. To determine this effect on particle size distribution of
milled refuse, the procedure outlined below was adopted.
                                81

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-------
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      Three samples of refuse shredded with the Tollemache mill
were collected every day over a 9-day test period. The samples
were collected after the first truckload of refuse milled each day,
and the date and number of tons of refuse milled since the last samples
were taken were recorded. Each sample, weighing about 7 Ibs.,
was collected in a plastic bag which was tied securely and labeled.
Duplicate analyses were carried out on each sample to determine
moisture content. Table 26 below shows the dates the sample was
collected, the number of tons milled since the last hammer change,
and the moisture content.

      The sieving technique described previously was used to determine
the particle size distribution of each sample.
                           TABLE 26

                   Dates  of Particle Size Tests

Old hammers
New hammers




New hammers
Date
(1972)
March 21
March 22
March 23
March 24
March 27
March 28
April 7
April 10
April 11
April 12
Tons Milled Since
Last Hammer Set
Replacement

0
107
210
323
435
0
70
210
326
Moisture
Content
24.0
30.4
27.6
24.4
25.0
18.97
32.9
23.7
18.1
24.0
Results and Discussion:

      Figures  24 and 25  show the resulting particle size distribu-
tions .  It is clear from the distributions that the older hammers did
produce a coarser product.  It is interesting to note that in the first
2 to 3 days after a new set of hammers was installed, there was
the most pronounced change in particle size distribution whereas
after milling about 300 tons of refuse, there was not such a pronounced
change in particle sizes .
                               84

-------
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Particle Size Changes During Routine Milling:

      To study the changes in the particle size distributions of
refuse milled with Gondard and Tollemache mills during normal
mill operations ,  samples were collected over approximately 1 yr.
The samples were analyzed for moisture content and particle sizes.
Some  samples  were unavailable during certain periods because
one mill or the other was not in use. Since the samples were collected
over a period  of close to 1 yr., they may be expected to reflect
all factors affecting particle size, such as moisture content, hammer
wear, refuse composition, mill operation, etc.  Samples taken include:

      a.  milled refuse from the Gondard mill only;

      b.  milled refuse from the Tollemache mill only;

      c.  milled refuse samples from both the Gondard and Tolle-
          mache mills.

The combined sample from both mills consists of approximately 71
percent from the Tollemache mill and 29 percent from the Gondard
mill.
Results and Discussion:

      Figures  26 , 27  ,  and 28 show the particle size distribution
curves for the samples described above. Moisture content was also
determined for each sample and is indicated in brackets on the plots.
Only particle size distributions and moisture contents of the samples
were determined.  It is seen that factors other than moisture content
were affecting the particle sizes. This effect is likely due to other
factors , of which hammer  wear is one described previously.  However,
these distribution curves  can be compared with each other, assuming
that the effects of refuse composition, mill operation, etc. are averaged
out. Thus , the fineness of grind can be compared for the two mills,
and the change in particle sizes  over the year,  for whatever reasons,
can be observed.

      It was found that the Gondard mill with a 5-in. grate produced
approximately the same particle  sizes as those produced by the
Tollemache mill over the period in question.
                               87

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Moisture Content:

      The percent moisture contents during the period of study
were plotted against time to get a general idea of the seasonal moisture
content variation.  The results are shown in Figure  29.

      The moisture content of milled refuse was found to be fairly
constant during the period from October to April. There was a
gradual increase in moisture content from 25 percent to 47 percent
for the period from May to August.  This increase may be due to
the heavy precipitation during the summer months and to the change
in composition which occurs in the summer, with increased amounts
of wet yard wastes , etc.

      However, a  statistical analysis showed that the moisture content
variation alone cannot explain the particle size variation observed
throughout the year.
                            DENSITY

INTRODUCTION:

      A practical consideration in milling and compacting refuse
for landfill is achieving maximum reduction in volume (i.e., higher
densities) , consistent with reasonable costs,  to assure maximum
utilization of disposal space and minimum subsequent settling.
Also,  it is more economical to transport high density material than
low density material to certain limits.

      It is important to know whether there is a significant differ-
ence in density between milled and unprocessed refuse, and whether
large compaction equipment producing considerable vibrations would
produce the same or high densities as achieved by milling. For
these reasons, tests comparing the densities of milled and unpro-
cessed refuse were conducted under a variety of experimental con-
ditions .

      Finally, there is a dearth of information on the effect of refuse
bridging in an enclosed space on the resulting refuse density.
To study the effect of bridging on density, compressibility tests
on milled and unprocessed refuse with and without a container were
also performed.

      The factors affecting the density of refuse are presented below.
                               91

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      1.  The composition of the refuse is important.  Depending
          on the percentage of light and heavy materials, the over-
          all density of a refuse sample will vary considerably.

      2.  High moisture content of refuse certainly influences the
          density, not only directly by increasing the weight be-
          cause of the added weight of the water, but also indirectly
          by improving the compactability of the refuse.

      3.  The type of machine used for compacting refuse in a land-
          fill affects the degree of compaction obtained. Several
          compactors are on the market, but steel-wheeled types
          appear to give highest densities.

      4.  Particle size is another factor that must be considered.
          Refuse broken into pieces normally requires less volume
          than unaltered refuse and will attain higher densities
          upon compaction.

      5.  In addition to the above factors, the number of machine
          passes,  lift height,  and spreading thickness will also
          affect the density.
EXPERIMENTAL PROCEDURE:

Equipment:

      A box 23-1/4 x 23-1/4 in. x 35-1/2 in. high was made out
of 3/4-in. thick plywood and used as the container for the compression
tests (Figure 30 ) . The four sides of the container were fixed together
with four 2 x 2 x 1/8-in. thick aluminum angles, and screws were
placed at the corners.  The bottom plate was fixed using wooden
pieces  along the sides as shown in the figure.  Stick cement was
used to fill all the corner openings to prevent leakage of leachate.
Care was taken to brace the container properly to make it strong
enough to withstand high pressures.

      To transfer the applied pressure and the vibrations to the
refuse  surface an iron plate 22 x 22 in. x 1/2 in. thick was prepared
as shown in Figure 31  . A threaded hole 1/2 in. in diameter was
drilled to attach the threaded rod from the electromagnetic vibrator.
Three pieces of pipe about 5 in. long and 3 in. in diameter were
welded on the plate at the proper inclinations to introduce the blunted
rod from the air hammer.  To measure the amount of vibration trans-
ferred  from the vibrator to the plate, a channel section 3 in. wide
                              93

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                                       II
                        SIDE PLATES
                        ALUMINIUM  ANGLE
                       WOODEN  PIECE
                        BOTTOM PLATE
Figure 30. Container Used for Compression Tests

             94

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 PLAN
                   IRON  PLATE (22"x22"xf )
                    .  HOLE
              -PIPE NO. 2  (5"x3MDIA.)
  PIPE  NO. 3(7x3")
  PIPE  NO. 1 (4"x3")
  C-CLAMP
  VIBRATION
  PICK- UP
CHANNEL  SECTION
SIDE  VIEW
                          IRON PLATE
Figure 31.   Iron Plate Used for Compression Tests
                       95

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and 4 in. long was welded near one of the corners of the plate.
The vibration pick-up was fixed to the channel with a 'C' clamp.

      A small box 14 x 14 x 28 in. was made to transfer the applied
pressure from the press to the iron plate and thereby to the refuse.
The press shaft was larger than the cross-sectional dimensions
of the container; thus it was necessary to use the box in between
the shaft and the iron plate.  The box was made strong enough to
withstand heavy loadings, using 2 x 4 in. wooden pieces on the
top and bottom, and 2 x 2 in. pieces at each corner and for the bracings
as shown in Figure  32 . Plywood planks were nailed to all sides.

      This entire assembly was placed in a 30-ft.  tall compression
machine, able to apply loads up to 1,000,000 Ibs., which is located
in the engineering mechanics laboratories of the University of Wis-
consin-Madison (Figure 33 ). The compression shaft of the machine
could be operated either by mechanical screws or by a hydraulic
mechanism. A compression cell indicates the exact amount of load
applied.  Figure  34  is a schematic of the unit.

      In order to simulate compaction in a landfill, it was necessary
to transfer vibrations to the refuse under compression.  This could
be accomplished either by vibrating the iron plate or by vibrating
the container itself.  Since the pressure to be applied was very
high (maximum about 120 psi)  it was decided to attempt to vibrate
the iron plate instead of the complete box.

      Of the possible mechanisms for producing vibrations, two
were actually used.

      A trial test was carried out using a 50-lb.-force  electromag-
netic vibrator.  It was observed that the vibrations transferred to
the plate were not as strong  as those found on the  landfill, so sub-
sequent tests were performed using a stronger vibrating machine.
Attempts were made to use a hydraulic hammer for this purpose,
but it soon became apparent that the unit was not providing sufficient
power.  The only alternative was to use an air hammer, even though
such a unit is fairly difficult to control and is noisy.

      A vibration meter, type 1553A, manufactured by the General
Radio Company, was used for measuring the vibrations. A pick-
up with one end attached to the meter and the other attached to the
vibrating object transfers the signal to the meter for measurement
of the amplitude, acceleration, velocity, and jerk of vibrations.
                               96

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                                     II  >, H
TOP  WOODEN  PIECE (2x4")
                     CORNER PIECE  (2Mx2H)
                     BRACING  ( 2"x2M)
                 BOTTOM WOODEN PIECE (2"x4M)
         SMALL  BOX
Figure 32.  Small Box Used In Compression Tests
                      97

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                                         LEGS
                                         THREADS

                                         SHAFT(RAM)
                                          SMALL BOX
                                          IRON  PLATE
                                          CONTAINER
                                            REFUSE

                                               FLOOR
                 UNIVERSAL  TESTING  MACHINE

Figure 34.  Universal Testing Machine Used for Compression Tests
                         99

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Field Study:

      A tractor moving across a landfill to spread and compact
refuse provides compaction by its absolute weight and also, it is
thought, by vibrations it transmits to the refuse.  The relative im-
portance of vibration in determining refuse density is not known
and is one of the factors considered in this study. In order to make
meaningful laboratory experiments possible, the vibrations actually
provided in a landfill had to be measured in some fashion.

      A vibration meter, as described previously, and a metal
plate 4 x 3 in. x 1/16 in.  thick were brought to the landfill site.
The meter was set on milled refuse approximately 8 ft. deep, and
7 ft.  away from the path a D-7 Caterpillar tractor was working.
The pick-up itself was placed on the metal plate which was then
placed on the refuse surface about 4 ft. away from the wheels of
the tractor.  Measurements were taken when the tractor was moving
both in the forward and reverse directions, and are shown in Table 27,
                         TABLE  27

                 Vibration Study on Landfill
              Displacement (mils)      Acceleration (in/sec2)
                  Triplicate	       Triplicate
Direction
Reverse

Forward
1
15

10
2
20

—
3
15

9
Average
.6

.5

14


.02

1
100

30
2
90

55
3
79

57
Average

70


.2

      The results in Table 27 indicate that when the tractor moves
in reverse it transfers vibrations of greater displacement and accelera-
tion than when it moves forward. The  average displacement was
found to be 14.02 mils (1 mil = 1/1000 in.) , and the frequency crudely
measured at approximately 6 cycles/sec.
                                100

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Laboratory Tests:

      Only one day's refuse was used for all the tests indicated
in Table  28 to minimize the effects of having large composition
changes from test to test.  Approximately 1 ton of residential refuse,
of apparently uniform composition, collected August 10,  1971, was
dumped on a cement slab.  About one-half of the refuse was dumped
in the feed hopper and milled with  the Tollemache mill.  The milled
refuse was placed in plastic bags which were tied securely.  The
unprocessed refuse was also placed in plastic bags after discarding
a few large items such as cardboard, concrete blocks, and long
metallic pieces. These bags were also tied securely to avoid loss
of moisture. All the bags with milled and unprocessed refuse were
brought to the laboratory the next morning.

      Samples of about 200 gms. each were taken from three randomly
selected bags of milled refuse, and analyzed for moisture content.
The moisture was found to range between 43.9 and 45.5 percent
on a dry weight basis .

      The ten tests indicated in Table 28  were carried  out on both
milled and unprocessed  refuse. The vibrations were classified
arbitrarily as light, medium, or heavy for the purpose of this experiment.
The displacement measured in the field study is approximately the
same as the medium classification used in the laboratory.
                           TABLE 28
                       Compression Tests
      Test
       No.
Refuse Sample
Test
        1   Milled
        2   Milled
        3   Milled
        4   Milled
        5   Milled
        6   Unprocessed
        7   Unprocessed
        8   Unprocessed
        9   Unprocessed
       10   Unprocessed
               No vibrations,  with container
               Light vibrations , with container
               Medium vibrations , with container
               Heavy vibrations , with container
               No vibrations,  without container
               No vibrations ,  with container
               Light vibrations, with container
               Medium vibrations, with container
               Heavy vibrations , with container
               No vibrations ,  without container
                             101

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                Test Without Vibrations

      The large container was placed so that its center coincided
with the center of the ram of the press.  Each bag of refuse used
was then weighed accurately to 0.1 Ib. and emptied into the con-
tainer .  Refuse was spread with a long wooden board to make the
surface somewhat even.  When the container was filled completely
with a known weight of refuse, the  iron plate shown in Figure  31
was placed on the refuse, followed by the small box shown in Figure  32
The initial density was computed at this time by measuring the volume
occupied by the refuse within the container and compressed slightly
by the iron plate and the small box. Next the compression shaft
was lowered until it just touched the top of the small box.  The con-
tainer , iron plate, small box, and the position of the shaft were
given a final check at this point to make sure that everything was
in line.

      Gradually the load was increased by 500-lb. increments  until
2,000 Ibs. was reached and then by 1,000- to 2,000-lb. increments
until the end of the test. Measurement of the empty space at the
top of the container was taken for each corresponding load to calculate
the densities at various pressures. When the plate was not abso-
lutely level, a measure of its location was taken on both high and
low sides to calculate the average depth.  The test was continued
until there was little or no movement of the iron plate after an in-
crease in load of about 2,000 Ibs.  At this point the shaft was raised
and the refuse was left in the container under the weight of the iron
plate and the small box.  One minute was allowed for relaxation
of the refuse after which the final measurement of the plate location
was taken for calculation of the springback.  The test with unpro-
cessed refuse  was carried out in similar fashion.
                 Tests With Vibrations

      A similar procedure was used when tests with vibrations
were undertaken.  The compressor was parked outside the laboratory
and the medium size air hammer of 60-lb. weight was connected
to the compressor with a rubber hose. A blunt, hexagonal rod about
30 in. long was attached to the hammer.  The other end of the rod
was introduced into pipe no. 1, shown in Figure 31  , which had
been welded securely to the iron plate.  The air hammer was held
in place by one person.

      The vibrator meter pick-up was attached with a 'C'  clamp
to the channel section provided on the iron plate.  Everything  was
checked for safety before the tests were begun.  The compressor
was started and the vibration meter turned on.
                               102

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      It was decided to vary the amount of vibration by varying
the pressure by which the air hammer was forced against the iron
plate, and by varying slightly the amount of air delivered to the
hammer. The three levels of vibration were characterized as light,
medium, and  heavy, where the vibration meter served to check
on the actual  amount of vibration delivered. The average amplitude
of vibrations  measured in the field study was 14.02 mils. Therefore,
the amplitude for light vibration was selected to average around
10 mils, medium vibration around 20 mils,  and heavy vibration between
30 and 40 mils.  Although the vibration system seemed at first to
be rather crude, experience made it possible to achieve and maintain
a reasonably  uniform vibration level.

      Loading was started by lowering the shaft until a momentary
high pressure of 200 Ibs. was achieved. This was necessary to
hold the small box and iron plate securely when vibrating was begun.
The vibration was started by allowing the air to pass through the
hammer. The amplitude of vibration was adjusted to meet the desired
level by adjusting the throttle valve controlling the amount of air
allowed to pass to the hammer and by trying to use constant pressure
on the hammer. The loadings and measurements of iron plate location
were recorded to calculate the density of refuse at the various pressures
and amplitudes of vibration. The amplitude of vibration was checked
continually during the test and adjusted whenever necessary.
The test was terminated after what seemed to be an unsafe situation
was attained or after there was little or no change in iron plate location
after a 2,000-lb. increase in loading.

                Tests Without Container

      After the compressibility tests using the container were completed,
the tests were milled and unprocessed refuse were carried out without
using the container. The plywood piece at the bottom of the container
was detached and all the screws from two opposite corners were
removed except for  six, one each at the top, bottom, and middle,
which were loosened but not removed.

      The compressibility tests as performed without vibration were
carried out in the normal fashion until about 700 Ibs. of loading
was achieved. At this point the refuse was under sufficient pressure
that the remaining six screws could be removed from the container
and the sides taken away without loose refuse  falling out of the compression
zone. The height of the refuse under compression was measured
and the corresponding loading was recorded.  The compression
test was then  continued in the normal manner noting the loading
and corresponding height of the refuse.  When the cross-section
                               103

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of refuse seemed to change, as when some of the components of
the refuse were found projecting out, a new cross-sectional area
was measured.  This was done by holding the corners of a wooden
piece tightly against the bulging refuse, and measuring the apparent
length and width of the refuse under compression.  The test was
terminated when little or no compression was attained after 2,000
Ibs.  of increased loading was applied.

RESULTS AND DISCUSSION

Compressibility Tests With Container:

      Figure 35 shows the plots of density in Ibs./cu.yd. vs. pressure
in Ibs./sq.in. for eight  compressibility tests using the container.
The results are on a wet-weight basis.  The following observations
can be made from the curves.

      All the curves show a rapid increase in density to a value
of about 15 psi pressure. After that point, increased pressure results
in relatively small density increases.  It is also shown that the curves
do not diverge or converge as the pressure increases.  Therefore,
the numerical increase in density by milling is approximately the
same at all pressures, but the percent increase decreases as the
pressure goes up.

      The curves for unprocessed refuse, and especially the one
without vibrations, show a fairly wide scatter of points which deviate
somewhat from the curves as shown. This scatter may be explained
by the breaking or flattening of various components of refuse, such
as glass bottles and cans , which resist pressure up to a point before
they are suddenly crushed.

      During the test on milled refuse with light vibrations, the
amplitude of vibrations was below the desired range.  This was
especially noticeable in  the 52- to 98-lb ./sq.in. pressure range.
Note that the resulting density is found to be lower in this range,
but that the density seemed to increase during the test on unprocessed
refuse  with medium vibrations in the 30- to 70-lb ./sq.in. pressure
range.

      The density of milled refuse was higher than that of unprocessed
refuse  under all pressures considered.  The average initial density
as placed in the container was 386 Ibs./cu.yd. in the case of milled
refuse  and 313 Ibs./cu.yd. in the case of unprocessed refuse samples
under study.
                               104

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     105

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      It is clear from the plots that the density of both milled and
unprocessed refuse was increased with increasing amplitude of
vibrations applied during compression. Also the density of milled
refuse at all levels of vibrations was found to be higher than the
corresponding density of unprocessed refuse.  The range of density
for milled refuse was 1,515 to 1,750 Ibs./cu.yd. going from zero
to heavy vibrations while the corresponding densities for the unprocessed
refuse were 1,305 to 1,493 Ibs./cu.yd., at 80 psi pressure. Table 29
gives the values of densities at 5 and 50 psi pressures, and also
gives the increase over unprocessed refuse and the percent increase
over no vibrations.

      Table 29 shows that the percent increase of density of milled
over unprocessed refuse is higher at 5 psi pressure than at 50 psi
pressure, the values being about 47 percent and 10 to 25 percent,
respectively. The percent increase from vibrations is more important
at low pressures than at high pressures in the case of unprocessed
refuse,  while it is relatively independent of pressure in the case
of milled refuse.  It is concluded that milling affects the  density
more  at lower ranges of pressure than at higher ranges, and that
the percent increase of density obtained by milling refuse is more
important than the percent increase in density obtained simply as
a result of vibrations .

      The springback tests indicated that the reduction  in density
due to relaxation of the refuse after  the external pressure was  released
was 21.9 percent with milled refuse and 22.1 percent with unprocessed
refuse.  This difference is insignificant. Table  30 indicates the
maximum density attained after compression and the reduction in
density due to springback.

      The Caterpillar tractor used at Madison's Refuse Reduction
Plant  is a D-7 1960 model, weighing approximately 35,000 pounds.
The overall size of the tractor is 18 ft.  x 7-1/2 ft. x 10 ft. in height
with two tracks which are 14 ft. x 14 in. each.  The average pressure
exerted by the tracks on the landfill would be approximately 7.5
Ibs./sq.in, From the plots at this pressure, the expected density
in the landfill using the medium vibration case which comes closest
to the vibrations measured in the field study, would be approximately
960 Ibs./cu.yd. with milled refuse, while the density of unprocessed
refuse would be approximately 660 Ibs./cu.yd. under the same
conditions.  These figures correspond  well with the values established
by field density measurements at Madison and other test sites .
Values cited range from appoximately 900 to 1,000 Ibs./cu.yd. in
the case of milled refuse and 600 to 700 Ibs./cu.yd. in the case
of unprocessed refuse.  Note that moisture content variations will
have  a significant effect on these  values and that they are strictly
                              106

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Construction of Special Test Cells in Remote Locations:

      The field studies suggested that milled refuse without cover
was no more attractive, and probably less attractive,  to rats than
was unprocessed refuse covered with earth.  It remained to be shown,
however,  whether milled refuse by itself would attract rodents .
To determine this , several tons of milled refuse were  placed in a
remote location within a Madison residential area.  The site was
fenced to keep out domestic animals and people, after  which it was
checked periodically for signs of rodent activity.  No  activity was
observed  after several months , and the test was terminated.

      The above test could not be considered conclusive in itself,
for there was no assurance that rats were living in the area, nor
was there any reason  to expect any rats nearby to leave their pre-
vious surroundings in favor of milled refuse.  Consequently, a
similar pile  of milled refuse was placed in a remote location at the
Olin Avenue Landfill where rats were known to be present.  After
several months no signs of activity were observed,  and the test
was terminated. Note  again, however, that the results are not necessarily
applicable to other locations.  Depending on other sites available
to the rats,  and whether nearby rat colonies have grown to the point
that these other sites are saturated,  the results of this test must
be subject to some uncertainty.
CONCLUSION

      It is felt that the combination of field tests described above
provides rather conclusive evidence that milled refuse of a composi-
tion found in Madison will not result in rat infestation at a landfill.
The fact that no rats have been sited at the landfill in the 2 years
since the rats were poisoned, and that a mother duck has felt suffi-
ciently secure to develop a nest and lay eggs near the center of
the site, supports the findings of the study.
                                138

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Some General Observations:

      The bait consumption method was found to provide meaningful
results in comparing the attractiveness to rats of the two basic cell
types .  It was found useful, however, to substantiate these results
with visual observations recorded during bait-replenishing tours
and during special tours taken solely to count burrows , to observe
paths and other signs of activity,  and to determine whether such
activity was recent.  Although simple bait consumption was found
to correctly indicate areas of activity in this case, it is suggested
that problems due to birds , other animals , wet or scattered feed,
etc.  may make results difficult to  interpret if visual observations
are not recorded.

      It was noted that any irregularity in the surface of a cell,
whether milled or unprocessed, was likely to lead to test drilling
or a burrow. A  large object such as a rock, part of a tree, or a
chair, if placed at or near the  surface of a cell, will disrupt the
uniformity of the surface or provide a break in the surface, making
that spot desirable for drilling. In this respect the covering of
cells can be detrimental, for erosion of the cover provides surface
irregularities which may lead  to test drilling.

      Note further that with milled, uncovered cells a break in the
surface is not as likely to result in burrows  as a comparable break
on an unprocessed, covered cell.  With milled cells the interior
offers only more of the same material as is encountered at the surface,
so a break is not necessarily conducive to extensive burrowing.
In unprocessed cells, however, when the cover material has been
penetrated, rats can develop long paths , make nests,  and rummage
for food without difficulty .

      In general, more burrows were found on unprocessed, covered
cells than on milled, uncovered cells.  Possible reasons for this
include the ease of finding  food in unprocessed refuse as opposed
to milled, in which  edible matter  is ground into relatively small
pieces  and distributed among nonedibles. The uniformly small
particles may also impair the drilling qualities of milled refuse;
for example, there would be litttle opportunity for burrowing under
larger objects to strengthen the ceiling of a tunnel in milled refuse.
Another reason may be the  obvious futility of burrowing in milled
refuse, for, as drilling proceeds, only more of the  same homogeneous
material is encountered. Most of the signs of test drilling without
burrow development were found on milled cells.
                                137

-------
                   Table 41  - Results of Phase C*
              Daily Weight of Bait Consumed
                  8-29
                  9-3
9-3
9-5
9-17
9-27
  Rate of Decrease
  in Consumption
8-26    8-29     9-3
 to       to       to
9-27    9-27     9-27
27
28
25
26
23
24
29
30
21
22
1
2
3
4
17
18
5
6
15
16
19
20
13
14
9
10
11
12
7
8
MCR
MCR
MCR
MCR
MCR
MCR
UCR
UCR
UCR
UCR
MG
MG
UG
UG
MR
MR
UR
UR
MCR
MCR
MCR
MCR
MCR
MCR
UCR
UCR
MCR
MCR
UCR
UCR
.26
.02
.64
.35
.27
.63

-
.05
.10
.14
.05
.32

.63
.34
.07
.04
.01
.09

.01
-
.21
.02
.01
.01
.57
-
.01

.01
.47
.07
.13
.19

-
.01
.14

.01
.14
.08
.34
.07
-
-
.01
.34
.40
.01
.08
.14
-
.01
.05
.30
-
.02
-
-
.25
.01
-
.22

-
-
-
.04
.10
.36
-
.05
.11
-
-
.03
-
.26
.02
-
.39
-
-
-
.10
-
-

-
.02
.02
-
.23

-



.01

.01
.04
.04
-
-
.06
.08
.14
-
.04
.25
-
-
-
.10
-
-
-
-
.01
.01
.06
.02

-
.01
.04
.01
.01
.02
.01
.02
.01
-
-
.10
.05
.03
-
.01
.02
-
-
-
.07
-
-
.0081
.0006
.0197
.0106
.0066
.0191

0
.0012
.0019
.0041
.0012
.0094

.0191
.0103
.0022
.0012
-.0028
.0012

.0003
-.0003
.0059'
.0006
.0003
.0003
.0156
0
.0003
.0003
.0003
.0158
.0021
.0024
.0059

0
0
.0034

0
.0042
.0024
.0110
.0021
0
0
-.0031
.0100
.0128
.0003
.0024
.0042
0
.0003
.0017
.0079
0
.0007
0
0
.0100
0
-.0025
.0083

0
-.0004
-.0016
.0012
.0038
.0142
-.0004
.0012
.0042
0
0
-.0029
-.0021
.0096
.0008
-.0004
.0152
0
0
0
.0012
0
0
* See bottom of Table 38 for definitions of terms or markings.
                             136

-------
      Results show that rat activity was drawn readily for distances
up to 100 ft. and that many of the original burrows were retained
while the rats simply moved to the new station locations for feeding.
In addition,  there was some drawing of rats into the central area
of the landfill from distances up to 400 ft.  This migration led to
much test drilling, resulting eventually in 18 new burrows. Of
these,  12 were on the two unprocessed, covered cells in the central
area; the remaining six were on one of the four milled, uncovered
cells in this area.  Thus,  it appears that the unprocessed, covered
cells provided better drilling and living conditions than did the
milled  cells.

      The fact that rats were drawn by the stations in Phase B does
not  negate the results from Phase A, for by the time Phase B was
initiated the rats were unnaturally dependent on the bait and were
willing to search for it. It should be noted that because of problems
associated with the presence of birds and other animals during this
phase, the bait consumption data were difficult to interpret;  therefore
the  visual observations were emphasized in reaching conclusions
for  Phase B.
Phase C:

      The last phase of the testing program consisted of adding
poison to the bait and observing the rate of kill. The practice of
using bait for several weeks to acclimate rats to a bait station, before
adding poison to the bait, helps produce an effective kill.  To assure
a thorough kill, the bait stations were moved back to their original
locations and nonpoisoned bait was used for almost 3 weeks prior
to poisoning. Three to 9 days after the addition of  5-percent-by-
weight anticoagulant rodenticide to the bait, the kill was essentially
complete. The rate of decrease of bait take was higher on the milled
refuse cells and lower on the unprocessed cells. This may suggest
that rats frequenting the milled cells were more dependent on the
bait than were rats associated with unprocessed cells (Table  41  ) .
                                135

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                                    134

-------
would have an identical bait station. This choice would then be
based on considerations other than the presence of a bait station
and would reflect the desirability of the site.

      Since previous results indicated that most activity was around
the periphery of the landfill, nearly all of the peripheral stations
were removed for Phase B, and nine stations were placed or allowed
to remain in the central area of the fill,  where previously there
had been neglible activity.  The results were reported in a table
similar to that shown for Phase A, except only one average was
necessary since there were no obvious trends in the data with  time
(Table 40)  .   The lack of such trends suggests that, whereas  in
Phase A the rats were initially not dependent on the bait, such a
dependency was well established by the time Phase B began.
                          TABLE   39

   Rank  of Daily Average Consumption According to Cell Type
                                                            \,

                  MILLED      UNPROCESSED
1**
-
4
Increasing
Take


' 3
5,6
7
-
11,12
13,14
17
..
2
-
4*
8
9* ,10
-
15*, 16*
-
      * Possibly an error from scattering.

     ** Milled garbage, not covered.  Take dropped sharply
        when sides were covered.
                                133

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                                            132

-------
consumptions at each station for the first and last portions of Phase A
were tabulated and ranked from the highest to the lowest.  Although
there was a definite trend at all stations toward increased take,
the ranking of the  stations remained essentially constant.  This
supports the conclusion that population growth and increased dependency
on the bait occurred throughout the test area, but that little movement
from one location to another resulted from the bait stations.  The
"corrected average" column lists average takes for each station,
modified to emphasize trends  in the take as well as visual observations.
Due to the lack of movement from one station to another during the
test, and the fact that initial  take rates were small and subject
to error, the adjusted readings are emphasized (Table 38  ) .

      Table 39 shows the ranking of the bait stations from the greatest
to smallest rate of bait consumption. Note that there  appears to
be no preference between cell types.  The highest takes observed
in this study occurred in bait stations located on cells constructed
of garbage. Since this was an obvious attractant, and since there
was much rat activity apparent on these cells, the high take rates
substantiate the validity of the test procedure.

      The ranking of stations from the highest take downward is
also noted on the map of cells, Figure  40  .  The highest takes occurred
around the periphery of the landfill, leading to the conclusion that
the desire of the rats to locate near the periphery of the site was
greater  than their preference for either milled or unprocessed refuse
cells.

      It  should be noted that  on one occasion ten  people were stationed
in eight cars around the landfill from dusk to midnight. At. half-
hour intervals headlights were turned  on for 30 seconds and the
rats counted.  Results were disappointing in that few rats were
seen; however,  those rats that were seen were concentrated in areas
where the bait stations had the highest take.

Phase B:

      The purpose of Phase B was to test the validity of the  previous
results by moving the stations to new locations. If the stations did
not draw activity with them, the consumption rates from Phase  A
would apparently reflect the desirability of the location of each station.
If,  on the other hand, the stations  did draw  activity, the rats could
be forced,  through appropriate station placement, into chosing
among the various new locations available to them, each of which
                               131

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                         130

-------
RESULTS AND DISCUSSION

      The test was divided into three phases,  as follows:

Phase A:

      Bait stations for this phase were approximately evenly distributed
throughout the 20 cells.  This test was  designed to reveal initial
areas of rat activity, as  established prior to the testing program.
The data were recorded for presentation as shown in Table 37  ,
where bait consumption  for each weighing of each station, several
average values for consumption from each station, and visual observations
in and near each station are tabulated.  There was some concern
about changes in levels  of rat activity on the various cells due to
presence of the bait stations. The different averages were tabulated
in an attempt to indicate whether such shifts occurred. The averages
for the first 40 days, the last 30 days, and the entire 70-day period
of this phase were tabulated for this purpose.  An additional value
termed the "corrected average" emphasized later readings if a definite
trend was observed.

      There were several problems in analyzing the data.  First,
it is possible that bait consumption was not proportional to rat activity
at a given location.  Also, animals other than rats may have been
using the stations.  Some rats may have been getting a larger portion
of their food from the stations than other rats.  Perhaps rats lived
on one cell  and simply traveled to a spot which they would not normally
visit to feed at a bait station. Recording visual signs of activity
was a valuable aid in meeting these  potential problems, since observa-
tions made it possible to determine whether a given station was
frequented by rats and whether these rats were living and rummaging
on that particular cell.  Further,  it  was pointed out by project consultants
that rats eat very little food  each  day, and that many of their activities
are designed not so much for feeding (assuming a minimum amount
of food is readily available)  as to satisfy their natural impulse to
scavenge.  Therefore, the preference of one cell type over the other
for rummaging and burrowing should not be affected by the presence
of attractive bait at several nearby locations.

      A second major problem was the possibility that the presence
of a bait station was drawing activity to a given cell.  Trends in
bait consumption rates with  time would be important in revealing
whether this potential problem existed. For this reason the average
                               129

-------
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-------
covered with dirt. By intermixing the two basic cell types throughout
the test area, effects of the surrounding environment were minimized.

      Of the variety of tests considered for evaluating the relative
activity of rats on a given type of cell, bait consumption was chosen
as the primary test for the field studies.  If identical bait stations
are located uniformly about an area, those stations showing increased
bait consumption should indicate particularly active spots within
the area.  The basic assumption is  that the stations are equivalent
as far as the rat is concerned, so it must make its own choice where
to burrow, eat, and scavenge based on merits beyond  the presence
of a station, of one location over another.

      Disadvantages of this method include possible changes in
rat habits when food and water  are readily available, and the difficulty
of separating rat activity from that of birds and other animals.
Advantages of the bait consumption method include low cost and
ease of operation.

      Sightings of rats by project personnel, evidence of feeding
(as on gourds growing in the area) , development of paths , and
the number and apparent activity of burrows are readily observable
indicators of rat activity.  Such sightings were used throughout
the study to supplement the findings obtained by bait consumption.

      Thirty bait stations (Figures 40 6 41) , holding up to 6 Ibs.
of bait and 1 qt. of water, were placed  as uniformly as possible
over the  landfill area as shown  in Figure 40.   Since rats tend  to
stay  in one place and use the same trails, each station was placed
near signs of rat activity, if such signs were  available within a
general area.  The bait consisted of 62.5 percent cracked corn,
18.75 percent wheat, 18.75 percent rolled oats, and 3.12 gal. of
peanut oil per 1,000 Ibs. bait.  No  poison was used.

      The bait containers were weighed regularly to determine
the amount of bait loss.  Visual evidence of activity was also recorded,
such as rat or other droppings , feathers, and wet or scattered bait
(the latter signs suggesting the presence of birds or gophers)  .
New burrows or changes in activity around older burrows were
also  noted.  These data were supplemented by a night sighting,
as well as placement of two piles of milled refuse, without cover,
in isolated areas to determine if rat activity would be drawn  to them.
                              127

-------
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                         TABLE  36
                Summary of Cell Construction
                   TYPE OF CELL*
Cell Number
1
2
3
4 a and b
5



6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Milled
X
X
X

X




X

X
X
X

X

X
X
X

X
X
X

Unprocessed Material
Refuse
Refuse
Refuse
X Refuse
Garbage



X Garbage
Rubbish
X Rubbish
Refuse
Refuse
Refuse
X Refuse
Refuse
X Refuse
Refuse
Refuse
Refuse
X Refuse
Refuse
Refuse
Refuse
X Refuse
Construction
Dates Remarks**
Fall, 1967
ii
u
ii
Winter ,1968 Initially ,
uncovered ,
later sides
were covered
u
u
n
ii
ii
u
ii
u
ii
Spring, 1968
u
II
II
Summer ,1968
M
II
II
**
Combined refuse is garbage plus rubbish as is normally collected.
Garbage and rubbish were specially collected for test purposes .

Except as noted, all milled cells were uncovered and all unmilled cells
were covered with at least 6 inches of dirt .
                           125

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                        v-  VECTORS

V-A - Rat and Fly Tests at Madison

                         INTRODUCTION

       The casual observer might expect that the practice of leaving
refuse uncovered for extended periods of time would result in vector
problems .  Experience in other countries , however,  indicates that
vector problems do not result if refuse is milled prior to landfilling.
To confirm these findings , field and laboratory studies of flies and
rats associated with milled and unprocessed refuse were undertaken.

      It would be difficult, if not impossible, to prove that vector
problems would never arise using uncovered milled refuse.  Vectors
will live and/or feed in the best location they can find.  This  means
that the results of any one test will depend on which  alternatives
are available to the vectors. Therefore,  the surrounding area must
be considered as part of  the test site, and this makes projections
to other localities very difficult.  Additional complications arise
due to climatic conditions , history of the test site, and changes
in vector populations.  Experience gathered during a comprehensive
study of potential vector  infestation at Madison is summarized in
this report.

      Unless noted otherwise, the tests to be described were conducted
at the Olin Avenue Landfill in Madison.  Over 20 cells of milled refuse
which were not covered, or unprocessed refuse covered with a
minimum of 6 in. of dirt in the usual sanitary landfill manner, were
constructed at the test site (Table 36 and Figure  40) . The cells
were rectangular and approximately 40 ft. in the  smallest dimension.
They were 5 to 6 ft. high, and were constructed entirely above
grade. All  cells were similarly compacted with a D-7 Caterpillar
Tractor;  however, this compaction of milled material was almost
incidental since high compaction was achieved during distribution
of material on the cells.  All cells were constructed with domestic
refuse.

                         RAT STUDIES

PROCEDURE

      Initial studies were designed to compare the attractiveness
to rats of milled refuse left uncovered and unprocessed refuse
                              124

-------
3)     Test results revealed that dry refuse densities of two milled
      refuse cells differed by only 16.2 percent even though one
      cell was compacted 78 percent longer.  Dry effective densities
      of the same two cells increased only 11.5 percent even though
      one cell was compacted 68 percent longer than the other.

4)     Test results indicate that milled refuse required approximately
      50 percent less cover dirt than unprocessed refuse to achieve
      the same degree of cover; in this case complete covering of
      the refuse.
                                123

-------
      An examination of Tables  34 and 35  reveals that,  while
using approximately the same refuse compaction time, the  in-place
density of the milled refuse Cell II was 934 Ibs./cu.yd., or 15.3
percent greater than that of the unprocessed refuse Cell I  on a dry-
weight basis. A comparison of refuse densities for Cells I and III,
again on a dry-weight basis,  shows that nearly equal densities
were obtained while only 12.33 hrs. of refuse compaction were used
on milled Cell III compared to 21.96 hrs.  on the unprocessed refuse
cell.

      Further comparisons using dry effective densities indicate
that Cell II had an effective density of 883 Ibs./cu.yd., or 22 percent
greater than  Cell I.  Comparing Cells III and I,  milled and unprocessed
refuse respectively, a 6.1 percent increase in dry effective density
was evident for the milled cell.  This increase becomes more significant
when it is realized that total compaction time on Cell III was 14.13
hrs. compared to the 24.54 hrs. used on Cell I.

      An examination of the figures for density and compaction effort
for Cells II and III is also very  interesting. For instance,  dry refuse
density of Cell II was increased only 16.2 percent even though the
refuse in Cell II was compacted 78 percent longer than that in Cell III.
A similar result is evident when dry effective densities are compared.
The dry effective density of Cell II increased only 11.5 percent
even though the  total compaction time used on Cell II was 68 percent
greater than  that used on Cell III.
CONCLUSIONS

      The controlled density tests as described in this section have
revealed the following facts concerning the landfilling of unprocessed
refuse vs . the landfilling of milled refuse:

1)    Utilizing approximately equal compaction times, a milled refuse
      cell showed a 15.3 percent increase in refuse density and
      a 22 percent increase in effective density over an unprocessed
      refuse cell on a dry-weight basis.

2)    Approximately equal dry refuse densities and dry effective
      densities were achieved in a comparison of a milled refuse
      cell and an unprocessed refuse cell when the unprocessed
      refuse cell was compacted an average of 76 percent longer
      than the milled refuse cell.
                               122

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-------
Cover Material Requirements:

      Dirt in this test was to be placed as an intermediate cover;
that is, enough dirt was to be used to completely cover the material
in a manner similar to the application of intermediate cover in sani-
tary landfill operations.  Table  33 contains a comparison of the
cover dirt applied to each cell and a comparison of the methods used
to determine the amount of dirt used. Also included is a comparison
of machine time needed to spread and compact the dirt.
                          TABLE  33

             Cover Material Volume and Machine Time
                    Used In Its Application

                        In-Place—Cu.Yd.
              Borrow     Cross  Field      Average
               Pit-      Section  Density     Volume-  Compaction
              Cu.Yd.    Method  Method     Cu.Yd.   Time—Hrs.

Cell No. 1*     292       286     281         286         2.58

Cell No. 2**    124       128     137         130         1.75

Cell No. 3**    150       151     160         154         1.80
 * Unprocessed refuse
** Milled refuse


      Data in Table 33  indicate that the average cover dirt require-
ment for the milled refuse cells was approximately 50 percent of
that required on the unprocessed cell.
Densities of Milled and Unprocessed Refuse Cells:

      Table 34  contains all pertinent data for density computations.
Table  35 shows the percentage increase or decrease of the densities
calculated in Table 34  using Cell I as a base.
                                119

-------
RESULTS

Compaction:

      As mentioned above, nearly equal weights of unprocessed
and milled refuse were placed in each cell.  Table 32  contains all
pertinent data in respect to weight, both wet and dry, final volumes
of the in-place refuse prior to cover dirt addition, and compaction
time used to place the refuse.
                          TABLE 32

             Wet and Dry Weights and  Total Volume
             of In-Place Refuse vs. Compaction Time

          Weight (Tons) % Moisture  Volume        Compaction
          Wet    Dry      (DWB)    Cu.  Yd.  Hrs.    Min./Dry-ton

Cell I*    1114    806       37.5       1992    21.96         1.6

Cell II**   1139    745       51.7       1598    21.96         1.8

Cell III**  1236    779       58.7       1938    12.33         0.9
 * Unprocessed refuse
** Milled refuse
      Two important facts may be observed from this data:

1)    On a dry-ton basis ,8.2 percent more refuse was placed in
      Cell I than Cell II; but the volume of in-place refuse in Cell I
      was 24.6 percent greater than Cell II, compaction time being
      equal.

2)    Again on a dry-ton basis, approximately 3.5 percent more
      refuse was placed in Cell I than in Cell  III;  at the same time
      the  volume of Cell I is approximately 3 percent greater than
      Cell III. But to achieve these nearly  equal figures required
      a 78 percent increase in  compaction time on Cell  I as compared
      to Cell III.
                             118

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      A Caterpillar 950B steel-wheeled compactor was used to spread
and compact the refuse (Figure 39 ) .  Great effort was taken to
accurately record compaction time used on each cell. The test plan
called for equal compactive effort to be expended on Cell I, unprocessed
refuse, and Cell II, milled refuse; Cell I was to be filled under
normal sanitary landfill conditions.  Cell III,  milled refuse, was
to be filled using a minimum of compactive effort.  The compaction
time used during the addition of cover to each cell was also recorded.

      The test began with placement of unprocessed refuse in Cell I
on July 17, 1972.  As stated, the cell was equipped with a ramp
to allow city packer trucks to deposit their loads as  near the fill
face as possible.  The cell was filled under normal sanitary landfill
conditions , except that cover dirt was applied only on top of the
cell, and not to the working  face, at the  end of each day.  The inclined-
face method of compaction was used.

      Packer trucks were carefully weighed at city  scales, and
care was taken not to allow a truck to deposit its load unless its
weight had been recorded.  Cover dirt was only applied to the top
of the cell, thus maximizing  the cell volume in relation to refuse
placed.  Polyethylene sheeting was used to cover the exposed portions
of the cell at the end of each day's operation.  Detailed data were
kept on compaction time, moisture content,  and cover dirt use,
as previously explained.

      Following completion of Cell I on July 25, 1972, filling of
Cell II with milled refuse was  started.  All procedures that applied
in filling Cell I were used with Cell II.  Careful controls were initiated
to guarantee that the same amount of compaction time was applied
to Cell II as to I.  Approximately the same wet weights were placed
in both cells .  The cell was completed on August 2,  1972.

      Cell  III was filled with milled refuse between  August 2 and
11, 1972.  Approximately 9 percent more refuse was placed in this
cell than in the previous two.  The only  difference between construction
of this cell and the previous two was that the  landfill operator was
instructed to use the least compaction time necessary to afford a
good landfill operation.
                               116

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      A detailed grid system was constructed over each unfilled
cell.  Initial cross sections were taken using common surveying
techniques at designated points on the grid system.  These points
were established  as references and used in all further surveys.
The cells were surveyed following completion of the filling process
and also after placement of cover dirt.  Surface borings were also
taken to determine cover dirt depths.  All data were then plotted
and volumes determined by planimeter.

      The composition of refuse  used in this test is typical of Madison's
refuse as determined by numerous separation studies.  Results
of these studies are given  in Appendix   N. Refuse used in filling
the cells was that regularly collected by city packer crews on normal
working runs covering the entire city.  No  bulky items such as
white goods or furniture were collected in the loads. The cells
were filled in July and August (Figure  38 ) .

      Moisture content for the two milled cells was determined by
taking six 1-lb. samples of milled refuse as delivered to the site
throughout each day.  The samples were dried at 75° C. to a constant
weight. Moisture content  was calculated on a dry-weight basis
(DWB) .

      For consistency, it was felt that moisture content of the un-
processed refuse  should also be  determined after milling.  Thus
throughout the daily filling operation of Cell I,  200- to  300-lb. samples
of unprocessed refuse were taken from the  cell and stored in a city
packer truck.  The truck and its load were  then taken to the refuse
reduction plant where the  unprocessed refuse sample was milled.
Six 1-lb. samples were then collected and moisture content was
determined as  described above.

      A final cover of dirt was placed on the cells once each cell
had been filled and surveying had been completed.  The operator,
who is experienced in working on sanitary  landfills, was instructed
to place only as much dirt on each completed cell as would be used
under ordinary sanitary landfill conditions.

      Cover dirt  volumes  were measured in the borrow pit and in
place by survey cross sections .  Cover dirt weights, moisture con-
tent, and in-place densities were also used to determine volumes.
Moisture content of the cover dirt was determined by oven drying
a 1,300-gm. sample to a constant weight at  75° C . Four dirt samples
were taken each day that cover was applied.
                                114

-------
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                  TABLE  31
Olin Avenue  Field Density Tests  (1967-68)
                                      Actual
Effective
Cell No.
Milled Cells
1
3
9
10
11
Ib
17
21

Unprocessed
4A
4B
12
18
22

Refuse
Volume
(cu. yd.)
1,120
1,500
1,090
1,820
2,090
1,370
1,340
1,250

Cells
3,010
1,440
4,390
2,865
1,245

Cover Refuse
Volume Weight
(cu. yd.) (wet-tons)
534
703
474
689
844
617
733
709
AVE.
670 1,045
550 683
2,190 1,456
1 ,455 1 ,268
635 548
AVE.
Refuse
Density
(Ib./cu. yd.)
950
940
870
760
810
900
1,090
1,130
930
700
950
660
880
880
810
Refuse
Density
(Ib./cu. yd.)
950
940
870
760
810
900
1,090
1,130
930
570
690
440
590
580
570
                      112

-------
IV-B - Field Density Tests

      Field density tests comparing milled and unprocessed refuse
were first completed in 1967 and 1968 at the Olin Avenue site.  All
cells, both milled and unprocessed, were compacted to a 6-ft.  depth
by a D-7 Caterpillar tractor.  Results of these tests indicated that
milled refuse in a landfill situation has an average actual density
of 930 Ibs./cu.yd., while unprocessed refuse has an average actual
and effective density of 810 Ibs./cu.yd. and an average effective
density of 570 Ibs ./cu.yd., all figures on a wet-weight basis .
For the purpose of comparing landfill space savings, the effective
refuse density figures are more meaningful because they include
the volume of cover dirt used  (Table  31 ) .  Results of the Olin
Avenue field density tests were in question, however, because of
the lack of control over such aspects as compaction time, cover
dirt usage, moisture content of the refuse, and size of the cells
used for comparison.  Thus, more in-depth tests were deemed necessary

      The new  density tests were designed io compare in-place
density of milled and unprocessed refuse placed with equal compactive
effort and to compare in-place densities of milled and unprocessed
refuse placed under normal sanitary landfill construction.  Cell I
was to be filled with unprocessed refuse.  Cell  II was to be filled
with milled refuse;  compaction time was to equal that used on Cell I.
Cell III was to be filled with milled refuse using only the compactive
effort necessary to achieve a good sanitary landfill. Cover dirt
was to be placed only on the top  of each cell. Further description
and the results  of the tests are presented below.
EXPERIMENTAL PROCEDURE

      Three cells with 2:1 side slopes were excavated adjacent
to the city-owned Truax landfill in 1972 .  Cell I was constructed
with a ramp to allow city packer trucks access to the fill working
face, thus minimizing blowing paper problems. Ramps were not
needed on Cells II and III since blowing problems  are almost nonexistent
with milled refuse.  The  8-ft.-deep cells  were designed to provide
a volume of over 2,000 cu. yd. and to be  able to hold approximately
1,000 tons of refuse each  (Figure 37 ) .
                                Ill

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valid only for the refuse used for these studies.  It is felt, however,
that the relative increase in density obtained with milled refuse
in these tests will also be found under most field conditions.

      Based on the above figures it can be concluded that there
is a definite increase in density with milled refuse in a landfill when
compared to landfills with unprocessed refuse. A further increase
in density can be achieved with either milled or unprocessed refuse
by vibrations applied during compaction of the refuse by heavy
compacting equipment.
Bridging Effect:

      Figure  36 shows the results of four special bridging effect
tests which were carried out on a sample of refuse collected April
20, 1972.  The composition of this refuse was different from the
samples used for the previous density tests.  The average moisture
content of this sample was 36.5 percent on  a dry weight basis.

      The plot shows again that the density of milled refuse was
consistently higher than the density of unprocessed refuse. This
was true whether or not a container was used, and at all pressures
applied.  The  density of milled refuse in the container was 1,545
Ibs./cu.yd. at 105 psi pressure while with unprocessed refuse
the corresponding density was 1,285 Ibs./cu.yd.

      The other two curves represent the results of tests run without
a container, in an attempt to eliminate possible bridging of refuse
due to the effect of the container walls.  If the bridging effect was
large, compressibility tests like those used in this study would
not give results valid for actual landfill situations . Again, higher
densities were obtained at all pressures with milled refuse. Note
that a bridging effect was present with both milled and unprocessed
refuse, where an increased density was attained at all pressures
when a container was not used.  The  reduction in density from use
of a container  was calculated by averaging the density values from
the curves at 30, 60,  and 90 psi pressures . It was found to be 4.3
percent and 9.1 percent in the cases of milled and unprocessed refuse
samples respectively. These figures give  an indication of the error
introduced by at least this one effect in applying the results of this
study to field conditions .
                                109

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                                     108

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                         FLY STUDIES
      The testing program to evaluate potential fly problems which
might from not covering milled refuse consisted of the following
parts:

      (1)    an evaluation of the relative numbers of flies present
            on or near uncovered milled and covered unprocessed
            refuse cells;

      (2)    studies in which flies emerging from refuse in large
            cages were counted;

      (3)    laboratory studies to determine whether flies could
            live and reproduce on milled refuse; and

      (4)    tests to determine the survival rate of maggots in refuse
            passing through the mill.

Each of these studies will be considered separately.  Note that the
latter three studies were undertaken by the Department of Entomology
at the University of Wisconsin-Madison under a special contract
with the project.
FIELD STUDIES ON RELATIVE ATTRACTIVENESS

      A comparison of the relative numbers of flies found on or
near the two types of refuse cells was made in much the same manner
as was done with rats. Such a comparison was necessary to show
whether the practice of not covering milled refuse would result
in more or less fly problems than found in sanitary landfills of standard
construction and acceptable with respect to fly densities .

      A Scudder Grille (Figure 42 ) was used to determine the
fly population.  The grille was made of 1/4 x  3/4 in. slats, 3 ft.
long, placed parallel and 3/4 in. apart on a frame. By providing
many edges, the grille makes use of the flies' habit of landing near
an edge.  The procedure for this study was to place the grille on
a cell and, after 30 sec. , count the number of flies on  the grille.
Normally this procedure was repeated six times for each cell.  Since
results were dependent on the weather,  counts were made only on
sunny days with temperatures  near 80° F, and wind velocities  less
than 5 mph.
                               139

-------
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      The results, as summarized on Table 42, indicate no marked
differences in the number of flies on milled or unprocessed cells.
The highest counts were obtained on milled uncovered fresh refuse
and on the two garbage cells;  the lowest counts occurred with un-
covered milled refuse.
                          TABLE  42

       Average Number of Flies Counted Per Observation
        Observations made weekly over two month period.
         Each observation includes 4 to 5 counts per cell.
                  AVERAGE NUMBER COUNTED
                  MILLED
UNPROCESSED
5.0*
-
-
1.2**
0.8
0.7
0.6
0.5
-
0.3,0.3
0.2,0.2
5 cells < 0 . 1
.
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-
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0.6
0.5
0.4,0.4
-
0.2,0.2
no cells <. 0.1
      * garbage , not covered

     ** under construction during counting period

    *** garbage, covered
      Portions of various cell surfaces were examined for fly larvae
to determine the ability of flies to live on the cells.  Few larvae
were found and no significant differences were noted between milled
and unprocessed cells in this respect.
                               141

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EMERGENCE STUDIES

      These studies were designed to determine the numbers of
flies emerging from comparable amounts of milled and unprocessed
refuse.  One-half of a load (approximately 2 tons)  of residential
refuse was placed on flat ground and compacted with a D-7 Caterpillar
tractor.  Another load of comparable refuse was milled and then
placed in two equal portions and similarly compacted.  Screened
cages measuring 10 x 10 x 6 ft. high  (Figure 43 )  were placed over
each of the three refuse piles and the flies in each cage were counted
periodically over the one month duration of the test.

      The results are shown in Table 43 .  Cage 1 contained the
unprocessed refuse and had significantly more flies over the period
of the experiment than did cage 3, which contained milled refuse.
Cage 2 also contained milled refuse and was identical to cage 3 until
the 12th day, when 1,200 adult flies and 2,000 maggots were added
to the refuse.  This was done to determine whether the lack of flies
emerging from milled refuse was due to the lack of viable flies or
maggots in the refuse, or to the inability of milled refuse to support
flies. The data indicates that flies were able to survive on milled
refuse, but that maggots were unable to complete their life cycle
and thus did not produce more flies.

      In summary, the cage tests indicated that very few flies emerged
from milled refuse as compared to unprocessed refuse.  Flies were
found to be able to survive on milled refuse, but maggots could
not do so.  It remained to show whether the mill provided an extra
benefit in reducing fly populations during the grinding process
and whether milled refuse could support flies under any environmental
conditions.
LABORATORY STUDIES

      Samples of fresh and 6-month-old milled refuse were used
for laboratory studies to determine whether this material could support
flies. The material was placed in four cartons (two fresh, two aged)
which were covered with cheesecloth.  Approximately 1,000 fly
eggs were introduced to one carton of each type of refuse.  The
refuse was moistened with distilled water and the cartons held at
80° F. and a relative humidity of 40 to 70 percent.  The test lasted
3 weeks.
                               142

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                                     144

-------
      With the freshly milled refuse, no flies were observed through-
out the test in the carton to which no eggs were added,  supporting
the cage studies which showed lack of fly emergence from milled
cells. In the carton to which the 1,000 eggs were added, approxi-
mately 1,000 flies were counted at the end of the 3-week life cycle,
suggesting that when milled refuse is properly moistened and is
subjected to optimal environmental conditions,  it will support flies
through the growth cycle.

      The 6-month-old refuse evidently contained some maggots
and/or eggs, for under  the closely controlled laboratory conditions
a few flies did emerge.  Note that these were not houseflies .  These
eggs or  maggots were probably picked up by the refuse  during
the 6 months it was part of a milled, uncovered refuse cell at the
landfill; they were able to emerge after subjection to the closely
controlled laboratory conditions. The aged refuse was not able to
support the life cycle of the added eggs, for approximately the same
number  of flies emerged when compared with the carton  to which
no eggs were added.

      In conclusion, the laboratory study showed that under optimum
growth conditions, fresh milled refuse could support the fly life
cycle. It is likely  that moisture content of the refuse is  a particularly
critical factor in determining whether the cycle  will be completed.
Aged refuse was a poor  medium for housefly development under
optimal laboratory conditions.
SURVIVAL OF MAGGOTS DURING MILLING

      It remained to show whether the various forms of fly life are
killed in passing through the mill.  On two occasions the mill was
cleared of refuse momentarily by stopping the feed conveyor.  In
the first trial 6 ,000 mature housefly maggots were scattered on perhaps
100 Ibs. of refuse on the feeding conveyor, which was started imme-
diately after clearing the mill to simulate the normal passage of
refuse through the mill.  The second trial was identical to the first
except 12,000 maggots were used.

      The refuse was collected on a large plastic sheet and examined
for living maggots. The refuse was then placed in plastic bags
and brought to the laboratory where samples of it were exposed
to the proper media and environmental conditions to assure that
any maggots which were overlooked would emerge as flies. In the
first trial no flies emerged; in the second 84 flies were counted.
                                145

-------
      It is possible that some maggots were lost in the mill; however,
care was taken to avoid this.  The most likely explanation for the
large decrease in viable maggots is that most of them were macerated
during the milling process .
CONCLUSION

      The studies described showed that there are several mechanisms
by which the fly population at a landfill constructed of milled refuse
without cover will be equal or less than that at a sanitary landfill
where unprocessed refuse is covered daily with  earth.  The milling
process in itself destroys nearly all forms of housefly life, probably
by maceration.  Second,  freshly milled refuse can support the fly
reproduction cycle only under optimum  conditions (moisture levels
are especially critical) which are not normally obtained in a landfill.
Third, once the refuse has aged for several months, even this ability
under optimum  conditions is destroyed. Finally, field studies suggested
that whether the flies originate from  refuse or elsewhere, they will
be no more , and probably less , attracted to milled uncovered refuse
than they will to unprocessed refuse with earth cover.

      It is noted that no one of the tests described provides proof
that no fly problems will exist with milled refuse; however, when
all of the tests are taken together the evidence becomes quite conclusive.
Note further that experience at the landfill over 5 years of operation
has supported the conclusion of this  study,  for there have been
comparatively few flies reported at the site.
                                 146

-------
V-B - Rat Studies at Purdue University

BACKGROUND

      Field tests and operational experience have indicated that
there is no apparent problem with rat infestation of milled refuse
landfilled without daily cover.  Field tests at the Olin Avenue Land-
fill led to the conclusion that there was no detectable difference
between  milled test cells without cover and unprocessed refuse
cells with cover soil as far as the presence of rats was concerned.
Burrow development was more likely on the unprocessed cells,
evidently because of the ease of burrowing and the  uneven surfaces
due to erosion.  Additional tests in which milled refuse was placed
in remote locations resulted in no observable drawing of rats.

      These tests, coupled with 6 years of experience at Madison
during which no rats have been observed on the milled refuse,
provide rather conclusive evidence that milled refuse without daily
cover does not present any new or unusual likelihood of rat prob-
lems on a landfill. The major problem with this conclusion is  that
it is strictly applicable only to Madison and the conditions of the
various tests involved in its formulation.

      Cage tests performed at Purdue University were designed
to force rats into depending solely on the milled refuse for sustenance.
The test  results should be absolute in the sense that rats can or
cannot survive on milled refuse having Madison's composition.
This is in contrast to the field tests and observations of landfills,
where one is measuring the relative  merits of the milled refuse and
other alternatives available to any rats in the vicinity.  If, for example,
a landfill site is located near a stream, the  banks of which are ideal
for burrowing, and large quantities  of corn are stored in readily
accessible bins nearby, the chances are that even an open dump
would be less desirable to rats  than  these other nearly ideal conditions.
Of course, over the long term,  the rat population would expand
to the level which the living conditions could support, in which
case the  open dump would eventually become infested as well.
The point is, however, that the  likelihood of a rat population at
a given site is dependent not only on the suitability of the site, but
also the suitability of alternatives presented by the  surrounding
area.

      In addition to the field and cage studies, the  reader is re-
ferred to the section on European observations for documentation
which should be helpful in assaying  potential rat problems at milled
refuse sites.
                              147

-------
SPECIFIC OBJECTIVES

      There were two specific objectives for this study:

(1)    determine whether rats can survive on a diet, of milled refuse,
      and

(2)    examine the effect of refuse composition on the ability to survive.


PROCEDURE

      Purdue University's Rodent Control Fund and the U.S.  Depart-
ment of the Interior maintain a Rodent Test Center at Lafayette,
Indiana, primarily for the purpose of testing baits and poisons.
This is one of the very few facilities in the country where "wild"
Norway rats (Rattus norvegicus) are maintained for test purposes.
Approximately 750 rats are kept in 2 large concrete-lined breeding
areas,  where the rats can burrow and live under nearly normal
circumstances until  they are trapped for test purposes. Figure  44
is a picture of this outdoor area.  All procedures are conducted
in accordance with specifications set up by the Rodent Control Fund.
The facilities and expertise were obtained on a contract basis for
the purposes of this project.

      Prime wild Norway rats, each weighing over 200 grams or
more, were used for the tests. Five males and 5 females were used
in each tank, and all tests were conducted to a logical  conclusion
or over a 15-day period,  whichever came first. Rats were trapped,
sexed, weighed, and placed in the test tanks.  Whole shell corn
and a commercial lab block,  plus water, were used in  the tanks
for a 24-hour period prior to testing. This was done to acclimate
the rats to the  test tanks by keeping them on the diet to which they
are accustomed.

      The test tanks were metal, 3 x 7 x 2 ft. high. Each tank was
divided by a partition located 30  in. from one end of the tank. The
partitions had  a 4 x  4 in. opening with a sliding door at the bottom
center. A 5-gallon can with one  end removed was blocked to stay
on its side and was used as a nest box.  One such can  was placed
in the smaller  end of each test tank. The portion of each tank containing
the next box was covered to darken the area. The animals were
contained in this area by the sliding door for cleaning
                               148

-------
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the other end of the cage and replenishing the feed supply.  For
the first series of tests,  the test tanks were kept inside a building
at 70° F. and in total darkness.  Because of a lack of space in the
building, the last two test series were conducted outside, but during
a season of the year when moderate temperatures (reaching in the
70's and 80's daily) were attained. In the outdoor tests the entire
test cages were covered to maintain darkness .  One of the test cages
used is shown in Figure  45 .

      Three test series were run.  In the first series  refuse believed
to be of "normal"  residential-light commercial composition, both
freshly milled and aged in the landfill, was used. Specially com-
posited refuse of higher garbage content were used in the second
test series, and again in the third series but at much  lower and
more realistic garbage content than the second series, The procedure
was to replace the corn-lab block with the appropriate amount of
milled refuse. The refuse was placed in the larger end of each test
tank,  and then replaced or replenished daily throughout the test
period as appropriate. No other source of food was available, al-
though water was available at all times.  Each day the rats were
observed, and weights were taken when necessary.
ADDITIONAL TEST CONDITIONS AND RESULTS

Test Series I:

      Milled samples were taken from what appeared to be typical
truckloads of residential-light commercial solid waste.  According
to the Public Health Service survey of the refuse composition at
Madison  (see Appendix   N) , the average garbage content was
15 percent,  and this value was assumed valid for the samples sent
to Purdue.  This material was milled and then promptly placed in
metal cans lined with plastic bags. The bags were tied securely
and the cans sealed for shipment. Aged milled refuse was also sent
in similar amounts to Purdue.  This material was dug from Cell HI,
at that time approximately 2 years old.  This milled refuse cell was
also  assumed to have contained 15 percent garbage.

      It was necessary for the purposes of this experiment to be
sure that there was sufficient food available in the milled refuse
to sustain the rats.  The accepted minimum requirement of food for
rats  is 30 grams of dry "organic matter" per rat per day,
                               150

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where organic matter is defined as edible and able to sustain life
for a rat.  This definition would exclude paper.  It seemed reasonable
for a first estimate to assume that the garbage matter in refuse is,
in fact,  equivalent to the "organic matter"  able to sustain rat life.
The minimum daily amount of refuse to sustain life may then be cal-
culated  as follows:

                30 grams  x 10 rats  = 300 grams
                  rat

At 15  percent garbage, assumed to be 50 percent water,

             300 grams  x    Ib.    =  8.83 Ibs,/day
            0.50 x 0.15    454 grams

Therefore, 8.83 Ibs. of milled solid waste  per day should contain
enough  food to sustain  10 rats , but just to  be sure, 30 Ibs. of this
material was actually made available to the rats at any given time.
This should have provided over three times the minimum amount
of food required to sustain life, thereby allowing for any errors
in the above assumptions .
                      Fresh  Milled Refuse

      This material was piled  to a 20-in. peak with a clear area
15 to 16 in. in front of the partitioned nest area.  By approximately
5: 00 p.m. each day the rats would move and scatter the material
to  a height of 8 to 10 in.  On the following morning , it would be
scattered over the floor area to a more or less uniform level of 3
to  4 in.

      Although there appeared to be more food available in the fresh
milled refuse than the aged, it was not sufficient to sustain life.
Two similar tests were run with this material.  During  the first
test, 2 animals were cannibalized on the eleventh night, one each
during the next 2 nights,  and  3 more on the fourteenth  night.  The
remaining 3 animals were extremely thin and weak and would have
died shortly; however, they were killed on the fifteenth day to terminate
the test.

      The second test was similar to the first, with 3 animals cannibalized
on the tenth night, one during each of the next 3 nights, and 2 on
the fourteenth night. Two animals were killed on the fifteenth day;
these animals were also very thin and weak.
                               152

-------
                       Aged Milled Refuse

      This material was piled to a 5 to 6 in. peak in two 16-1/2
x 1 in. metal pans, leaving 4-1/2 in. on each side and 10-1/2 in.
on each end in the feeding end of the test tanks .

      This damp, heavy, compact material was picked over first,
after which the animals  would dig holes  and scatter the material
in search of food. The rats moved the plastic material into the nest
box for bedding.

      This test was also run in duplicate.  In the first case all animals
were showing weight loss by the  fourth  day. During the fifth night
one animal was cannibalized, one on the sixth night, 2 on the seventh
night,  and one on each of the next 5 nights. The last animal died
the afternoon of the sixteenth day.

      The second test was almost identical to the first except the
last animal was killed at the end of 15 days.
                          Observations

      Animal activity was checked several times a day during all
tests.  Due to total darkness , the normal feeding behavior was broken.
During observation periods, animals were seen searching both types
of waste material for food.  This would indicate a continued desire
for food which was not satisfied from the available material.

      During each of the tests there was very little activity the
first day.  The second day very little change was observed in the
aged refuse, but the fresh milled material was scattered.  New ma-
terial was added on the third day to each tank, and daily thereafter.

      The conclusion of this test series , applicable to the refuse
as received, is that it appears impossible for either freshly milled
or aged milled refuse to sustain a rat population. Note that the conclu-
sion does not preclude the possibility of a few rats moving in and
out of an area where milled solid waste is deposited.
                               153

-------
Test Series II:

      The primary objective of the second test series was to evaluate
the ability of rats to survive on a diet of milled refuse containing
various predetermined fractions of garbage or food wastes.  In con-
trast to Series I, the material used for this test was mixed in the
desired proportions from the garbage and nongarbage fractions
of residential-light commercial solid waste. The waste had  been
dumped on a flat surface at the mill, sorted into garbage and nongarbage
fractions by hand, mixed into the desired proportions, covered
with plastic sheets , and milled the next morning.  Replicate samples
of the milled material were taken of each of the 5 different composi-
tions tested and of the excess garbage for moisture content determi-
nation.  The composition of the material sent to Purdue is given
in Table  44.
                           TABLE  44

           Schedule of Samples to be  Tested,  Series II

Weight dry garbage     20 Ibs.      20      20      20      20

Weight wet garbage     54 Ibs.      54      54      54      54

Total sample weight    320 Ibs.    167     114      91      67

% Wet garbage                  S
  (wet weight basis)     17    /•"     32      47      59      81

Amount to be fed
 per cage per day*     21.3 Ibs.    11.1     7.6    6.1     4.5

*Assuming 60 grams of dry garbage per rat per day (double daily
 minimum requirements, assuming garbage is able to sustain life)
Immediately after milling,  the various compositions of waste were
placed in cardboard barrels lined with sealed plastic bags, covered,
and transported to Purdue where they were refrigerated until use.

      The procedure used for milling the various compositions is
of special interest.  Because of the large amount of work involved
                               154

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in mixing unprocessed refuse, only slightly more than those quanti-
ties necessary for the cage tests were made up.  Piles of these various
compositions were then placed on the feed conveyor of the Tollemache
mill and ground and bagged separately,  to keep them distinct, for
shipment.  One of the results of this procedure, as will be apparent
later in this report, is that an abnormally coarse particle size of
the milled material resulted.

      Four levels of garbage content were tested at Purdue—the
17, 32, 47, and 59 percent.  Two levels were run concurrently for
at least 2 weeks.  The tests were run outside, with the cages covered
by canvas awnings.  Five male and 5 female rats were used  in each
test.  The animals were conditioned to the tanks for 3 days,  during
which they were fed the same rations as  were being fed in the large
holding pens.  On the fourth day the animals were weighed  and
the appropriate amount of milled refuse introduced to begin  the
test.  Water and refuse were changed and the  rats weighed daily.
The results of the weighings are summarized in Table 45 .
                          TABLE 45

             Results of Purdue Rat Tests, Series  II    .  - -

Garbage content (%)                    17       32      47      59

No. of days of test period               15       15      18      18

Total wt. of males-initial (grams)     2279     2312    2035    2440
Total wt. of males-final  (grams)       2091     2064    2083    2129
  Total wt. loss of males (grams)      188     248    (-) 48     311

Total wt. of females-initial  (grams)    1822     1880    1985    1926
Total wt. of females-final (grams)     1576     1619    1686    1602
  Total wt. loss of females  (grams)     246     261     299     324
      No animals died as a result of starvation or cannibalism.
There was some weight loss, but no significant trends are observable
between weight loss and garbage content.
                               155

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      A likely reason for the apparently contradictory results of
this test series in comparison with the previous one is some unexplainable
mixing of small portions of unprocessed refuse with the milled refuse.
Another possibility is that heavy wet food wastes were able to fall
rapidly through the mill and leave the mill relatively unground.
Paper and other materials normally tend to retard the rapid flow
of refuse through the mill, giving a finer grind. Also, having allowed
the mill to clear itself before feeding each pile promoted an unhindered
fall of the initial portions of each refuse batch through the mill,
and some of the batches were so small that steady grinding conditions
were never reached,  The coarse grind resulted in edible matter
readily available to the rats  (Figure 46  ) .

      The conclusion reached from this test series is that particle
size is of special importance in determining the suitability of milled
refuse for sustaining the life of rats.
Test Series III:

      Test Series III was designed to correct the problems encountered
in Series II and thus to determine the effect of various garbage con-
tents in milled refuse on the ability of that refuse to support rat
life. In order  to avoid the effort involved in separating garbage
from the residential-light commercial wastes collected in Madison,
special arrangements were made to obtain garbage and garbage-
free refuse from a restaurant and a nearby village,  respectively.
The restaurant is a high volume operation which normally uses
large garbage grinders to dispose of food wastes in the sewerage
system.  Over a weekend, the busiest period of the week, the management
agreed to place the wastes in barrels lined with several plastic bags.
Approximately 300 Ibs.  of food scraps were collected, the bags tied
securely, and stored at 4° C .  until needed a few days later. This
waste was undoubtedly  closer to being 100 percent food for rats
than the handpicked garbage used in previous tests.  No paper,
plastic, metals, or  glass was included. There was  some concern
over what seemed to be a large fraction of chicken bones, so the
larger ones were removed and not used for subsequent testing.

      The garbage-free refuse was obtained from the regular collec-
tion vehicles used in the village of Shorewood Hills, Wisconsin.
This village has garbage grinders in all of the residences, and has
no industry and virtually no commercial solid waste.  The village
president was very cooperative, and instructed the collection crew
                               156

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157

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to avoid food wastes or garbage as much as possible during pickup.
Thus large amounts of food wastes which would not normally be
ground in a garbage grinder were avoided as much as possible
by the action of the collection crews.  Once this material was dumped
on the floor at the mill, an estimated 3 to 5 percent of garbage matter
was removed by hand to provide extra insurance that the refuse
as mixed was of accurate composition.

      The desired mixture of garbage and rubbish was mixed and
placed on the feed conveyor to the Tollemache mill.  Twice the re-
quired amount was milled. The first and last quarters of the milled
product were not used for the tests.  Preliminary testing indicated
that, if the first and last quarters were  125 Ibs. or more, beginning
and end effects on the particle size would be most noticeable in these
quarters, leaving a good grind in the center half of the milled material.
As a further precaution, new hammers were installed in the mill
shortly before  it was used to prepare the refuse for testing at Purdue.
Multiple samples were taken  of the milled refuse product and garbage
for moisture content determination. The milled material was placed
in plastic-lined fiber drums which were sealed and transported
to Purdue where they were held under refrigeration until use.
The composition of the material used for testing is shown  in Table 46 .
Note that only  50 percent excess garbage was provided per rat per
day above the minimum average requirement.  This reflects the
much greater likelihood that  the garbage in this test series was
more nearly 100 percent utilizeable by rats than the garbage used
in the previous cage tests.
                          TABLE  46

              Samples Tested at Purdue, Series III

Weight dry garbage                      14 Ibs.      15 Ibs.

Weight wet garbage                      50 Ibs.      50 Ibs.

Total sample weight                     500 Ibs.     250 Ibs.

Percent wet garbage (wet-weight basis)    10%         20%

Amount to be fed per cage per day*       35.7 Ibs.    16.7 Ibs.

  *Based on 45 grams of dry garbage per rat per day, which
   is 50 percent more than the normal daily requirement.
                               158

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      The cage tests were run at Purdue following the same proce-
dure used for Series II, except that the daily rations of milled refuse
were reduced proportionately whenever an animal died.

      The results were that all 10 animals died within the 15-day
duration of the test with the 20 percent garbage material, whereas
only 5 of the 10 animals died in the test using the 10 percent garbage
material.  The 20 percent test would seem to confirm Series I results
that rats cannot survive on a diet of only milled refuse (except in
the earlier test 15 percent garbage was assumed, while in this  test
20 percent garbage was known to be present) .

      The results of the 10 percent garbage test indicate that this
material is certainly  not conducive to survival, with half of the ori-
ginal 10 rats dead after 15 days. However, the results are not as
conclusive as would be expected since 5 rats did survive.  Of the
5 survivors, 4 were very weak and would have died shortly had
the test  continued, while the fifth was a dominant male which seemed
to thrive.  Extensive discussions were held with Purdue personnel
about this test in an attempt to understand its outcome.  The follow-
ing possibilities were noted:

1)    The labels on the 10 and 20 percent samples were reversed.
      This is very unlikely, as 250 Ibs. of 20 percent and 500 Ibs.
      of 10 percent material were sent, and then weighed in correctly
      at Purdue.

2)    The samples were initially  mixed incorrectly. This also
      appears unlikely as twice  as much of the 10 percent material
      was prepared  (1,000 as opposed to 500 Ibs.) , yet  an equal
      amount of garbage was used  in each case (100 Ibs.) .

3)    The 10 percent  sample was  not of uniform  composition.
      Mixing prior to milling, plus the mixing effect of milling makes
      this unlikely,  although it does remain a possibility.

4)    A coarse particle size was  obtained with the 10  percent
      sample. This  does not seem to be the cause, since the grind
      appeared to be equally fine in each case and special attention
      was given to this matter as a result of the previous test series.

5)    The make-up  of the 10 rats selected for the 10 percent
      test led to the results.  This appears to offer a plausible
      explanation of the results although it still seems unlikely.
      Rats were trapped and removed from the large outdoor pens
                               159

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      for testing.  Those rats which were too small (.Less than 300
      grams) or apparently not in good physical condition were
      not used in the tests .  In practice, 3 times as many rats as
      needed for the test are generally trapped so the selection
      criteria are quite rigid. The goal is to get 10 similar and
      compatible rats , which is , of course, not always possible.
      One of the reasons for the acclimation period in the test cages
      prior to the actual test is to check for compatibility in a con-
      fined area.

      It is possible in the 10 percent test that 5 relatively  weak
and 5 relatively strong rats  were selected, and that one of the 5
stronger rats was the dominant male. Thus, by fighting off the
weaker rats , the 5 stronger rats were able to get what food was
available through cannibalism and in the milled refuse.  This food,
plus stored  energy, enabled the stronger animals to survive.  The
dominant male was probably very good at this,  and he survived
quite well.  If the test were  continued, the weaker rats would have
died and the dominant male would probably have continued to live
for some time, surviving again by fighting other rats to cannibalize
them or get  available  food.  It is doubtful that he could have survived
long solely on milled refuse.

      It is interesting to note that in test Series II,  the females,
which had art average initial weight of 381 grams,  lost 15 percent
of their weight during the test period; whereas, the males weighed
453 grams on the average initially  and lost 5.5 percent of their initial
weight. This supports the statement that the larger, more dominant
rats  tend to thrive better, and lends weight to this explanation of
the results of the 10 percent garbage test.

6)    Maybe the 10 percent results are  not the entire problem
      and the 20 percent results  should also  be examined
      more  carefully. It is interesting  to note that the results of
      Series I, with freshly milled refuse of approximately 15 percent
      garbage content, were that 3 and 2 rats  remained at the end
      of the duplicate 15-day experiments .  This is not that different
      from the 10 percent results and, in fact,  the 20 percent results
      could have led to the  apparent dissimilarities in the third
      test series.  It  is possible, for example, that 10 rats of relatively
      equal strength  were selected in the 20 percent test so no rats
      could become so dominant as to win sufficient food to exist
      for the entire test period.
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      No matter what the reason for the survival of half the rats
in the 10 percent tests,  the results of this test series still lead to
the conclusion that rats cannot survive indefinitely on a diet con-
sisting only of milled refuse.
CONCLUSIONS

      The conclusions resulting from the confined cage studies
in which rats were fed only milled refuse, subject to the conditions
of the experiment, are as follows:

1)    Rats are not able to survive on milled refuse containing up
      to 20 percent wet garbage on a wet-weight basis.  They become
      progressively weaker with time and resort to cannibalism
      to prolong survival.

2)    The particle size of the milled refuse is of great importance.
      Rats did survive on poorly ground solid waste containing
      as little as 17 percent garbage, although there was close
      to a 12 percent average weight loss over the 15-day test period
      with this material.

3)    All cage tests were conducted in an admittedly biased situa-
      tion , which would make the results more positive than under
      actual field conditions.  Normally rats  will simply move to
      a more desirable location when faced with something they
      do not like, but in the cage tests there was no choice.  Thus,
      in interpreting these  tests, where the rats could not live on
      the material in a no-alternative situation,  it should be noted
      that there is even less possibility for rat infestation and survival
      in a milled refuse landfill than apparent from the cage studies.
                                161

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            VI. PRODUCTS OF DECOMPOSITION-LEACHATE AND GAS


VT-A - Olin Avenue Field Studies
     One of the goals of the City of Madison refuse milling project is
to evaluate the use of milled refuse in a landfill situation.  Of par-
ticular importance in this regard is the effect of milled refuse in a
landfill on the environment, and the effect milling has on the rate of
stabilization of refuse, if any.  Two basic landfill constructions have
been investigated:  milled refuse compacted and left without cover and
unprocessed refuse compacted and covered with earth.  These were monitored
to have a. basis for comparing their effects on the surrounding environment.
Indicators of the pollutional and decomposition effects are the amount and
composition of the collected water and composition of the gas emanating
from the refuse piles.

     The leachate (water) analysis has shown that milled refuse decomposes
faster than unprocessed refuse.  The two basic parameters used to show
this decomposition are chemical oxygen demand (COD) and specific conduc-
tance.  Other leachate parameters included volume collected, pH, biological
oxygen demand (BOD), hardness, alkalinity, chlorides, nitrogen, and phosphorus,
Gas analysis indicating increased levels of methane gas showed that
the refuse was decomposing; however, due to the effects of factors which
could not be controlled, it is difficult to use gas results to compare the
relative decomposition rates between the two cell constructions.
                                    162

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INTRODUCTION
     This section presents the results of outdoor studies on the relative
degradation characteristics of milled refuse without daily cover, com-
pared with unprocessed refuse covered in the normal sanitary landfill
manner.  Degradation and the attendant pollutant production were evalu-
ated by monitoring leachate and gas production.  The reader is referred
to the definitions at the beginning of the report where terms used
routinely in this and following sections are defined.
                                  163

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General Cell Set-up:

     To conduct this evaluation of the environmental effects of solid waste
degradation, 22 test cells were constructed at Madison's Olin Avenue land-
fill site between October 1967 and August 1968, as shown in Figure 47.   Unpro-
cessed combined refuse  (UCR) cells were constructed by placing the refuse
in layers, compacting them with a D-7 Caterpillar tractor, and then covering
them with at least 6 in. of earth to represent the typical sanitary landfill
situation.  The milled  combined refuse (MCR) cells were placed and compacted
in similar fashion, but were not covered.

     In addition, four  special cells were constructed only for experimental
purposes to represent the extremes in landfill situations.  Material for
these cells was obtained from a separate garbage collection being operated
at that time on the east side of Madison.  Two of the cells were composed
of garbage (food wastes) - one unprocessed  (UG) with 6 in. of earth cover
and the other milled (MG) without earth cover.  The other two special cells
were composed of rubbish - one unprocessed  (UR) and the other milled (MR),
with and without earth  cover respectively.

     All of the cells were approximately 5 to 6 ft. deep with lengths and
widths ranging from 40  to 200 ft.  No two cells were alike.  Data on the
cells of particular interest to this report are given in Table 47.   (Note
that some of the cells which were not instrumented for monitoring either
gas or leachate are excluded from this list.)

                         Experimental Procedure

     The environmental  effects of solid waste degradation were evaluated
through the study of physical, chemical, and microbiological changes which
occurred in the various cells during decomposition.  More specifically,  tests
were conducted on the leachate and gas produced by the cells.

     Of special importance to any study of refuse decomposition is the  compo-
sition of the refuse.   During this study period, the federal government  con-
ducted several tests on the composition of Madison's solid waste, as indicated
in Appendix   N.  The results suggest that the refuse is generally typical
when compared with national figures or data available from other municipalities.

Leachate Sampling and Testing;

                         Reservoir Construction
     In cells 2, 3, 4b, 5 through 14, 21 and 22, bell-mouth concrete pipes
were placed vertically  in holes dug beneath the cell bottoms, with the  lower
ends sealed with concrete to act as leachate collection reservoirs.  Pro-
jecting up from the bell-mouth end of each pipe and through the refuse was
a 6-in.-inside-diameter polyvinyl chloride pipe.  Just above the bell-mouth,
slits were made in the  PVC pipe to allow passage of leachate into the concrete
reservoir.  Leachate was directed to the slits by use of a 40 x 40 ft.  section
of plastic sheeting sloped to the reservoir.  The upper end of the PVC pipe
was capped with galvanized metal to exclude precipitation from the reservoir
and to minimize evaporation losses.
                                    164

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                              165

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                                  TABLE 47

                 Summary of Test Cells - Olin Avtenue Site
    Cell No.
    And Tvoe
  MILLED CELLS

       1
       2
       3
       9
      10
      11
      13
      15
      16
      17
      19
      20
      21
      23
       5
       7
Type of Waste         Grate Size
 Composition   Tons  Used  in Milling  Period of Construction
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Garbaqe
    Rubbish
534
450
703
474
689
844
319
617
739
733
499
430
709
420
103
310
3 1/2
2
6 1/4
6 1/4
3 1/2
6 1/4
3 1/2
3 1/2
6 1/4
5
5
4
6 1/4
5
6 1/4
6 1/4
Sept. 18
Oct. 9 -
Oct. 30 -
Dec. 11 -
Jan. 2 -
Feb. 2 -
March 18
April 1 -
April 22
May 13 -
June 3 -
July 8 -
July 29 -
Oct. 10 -
Nov. 20 -
Nov. 27 -
- Oct. 6, 1967
27, 1967
Nov. 17, 1967
29, 1967
Feb. 1, 1968
March 18, 1968
- 29, 1968
19, 1968
- May 13, 1968
31 ,1968
14, 1968
20, 1968
Auq. 20, 1968
22, 1968
Dec. 1, 1967
Dec. 8, 1967
UNPROCESSED CELLS

       4A
       4B
      12
      14
      18
      22
       6
       8
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Refuse
    Garbage
    Rubbish
1045
 683
1456
 197
1268
 548
  38
 400
Sept. 18 - Oct. 18, 1967
Oct. 23 - Nov. 17, 1967
Jan. 8 - March 15, 1968
March 18 - 29, 1968
April 1 - May 31, 1968
July 29 - Aug. 20, 1968
Dec. 4-8, 1967
Feb. 12 - March 5, 1968
                                    166

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                             Field Sampling

     To obtain a leachate sample, the following procedure was used.  The  gal-
vanized metal cover was removed and rubber tubing of sufficient length was
dropped into the reservoir.  Connected to the rubber tubing were a 2-liter
sampling flask, a trap flask, and a vacuum pump, in that order.  Electricity
to run the pump was supplied by a portable gas generator.  The trap flask
was used to prevent leachate from accidentally getting to the vacuum pump and
causing damage.

     Data obtained in the field included the amount of leachate pumped  (in
milliliters) and the temperature of the leachate (in degrees centigrade).
Temperature was obtained by securing a thermometer to a lath, lowering it
into the leachate, and then pulling it out quickly for recording.

     In obtaining a sample, the first 2,000 milliliters were discarded.   The
sample was obtained from the second 2,000 milliliters to make sure that any
leachate from previous samplings would be rinsed out of the flask.

                          Laboratory Analysis

     Previous experience with leachate analysis has indicated that results
will vary due to interferences being present which depend on the amount of
suspended matter in the sample.  Furthermore, the amount of suspended matter
is a function of many uncontrollable factors not necessarily related to the
decomposition process.  This problem was overcome by using a decanting
technique.  When a sample was brought in, it was shaken and then left to
settle.  After 4 hours the supernatant was decanted off.  All samples were
treated in the same way.  Data show that the samples after decanting were low
and uniform in suspended solids.  This procedure is felt to correspond to
actual landfill conditions where most suspended matter will be filtered from
the leachate by passing through a few inches of soil.

     Leachate commonly contains a wide variety of compounds or contaminants,
frequently in very large concentrations.  Rather than attempt to obtain the
concentrations of each of the many species that might be present, it was
decided to categorize the more important ones and use gross analyses to
determine their presence as a group wherever possible.  In addition, certain
species were analyzed because of their individual importance, or because  they
represent a group of similar species which are of interest.

     The following analyses were conducted on the leachate samples obtained:

     CHEMICAL OXYGEN DEMAND:  The chemical oxygen demand (COD) is a widely
used evaluation of the amount of oxygen needed to oxidize chemically the
matter in a water sample.  As used for these studies, the test results may
be considered primarily related to the amount of organic matter although, in
anaerobic waters with high concentrations of oxidizable cations, inorganics
can add to the COD as well.  The test was run according to the procedure  de-
lineated in the 12th edition of Standard Methods.  Because of the very high
levels of COD in the leachate samples, dilution with distilled water was
sometimes required prior to analysis.
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     CONDUCTIVITY:  Like the COD test, conductivity, or more correctly spec-
ific conductance, is a gross indicator of the total concentration of a major
classification of contaminants in water.  The test results may be considered
a measure of the concentration of dissolved inorganic matter, or ions, and
is commonly related to the total dissolved solids (IDS).  Conductivity plus
COD give a good indication of the organic and inorganic content, respectively,
of a water sample reasonably free of particulate matter.  This test was run
using a conductivity bridge, Model RC16B2, made by Industrial Instruments.

     pH:  pH is a measure of the hydrogen ion concentration and it was found
to be an indicator of the state of refuse decomposition.  Values were obtained
using a Beckmari Zeromatic II, Model 96A, pH meter.

     ALKALINITY:  Alkalinity was measured by titration to pH 4.3 using a
pH meter.

     TOTAL AND CALCIUM HARDNESS:  Bach kits which incorporate a micro
version of the EDTA titration method for hardness were used to determine
total and calcium hardness.  Kits HA-71 and HA4P were used following the
directions supplied with the kits.  The Standard Methods EDTA titration
procedure was used during the last project year and as a periodic check
on the Bach kit: results.  Comparison between the two methods was close
enough to allow continued use of the Each kits.

     CHLORIDES::  Chlorides were tested initially using a Hach kit, Model
7-P.  Only samples collected after March 1969 were run.  It should be
noted that in the latter part of the project, a full-time chemist was
employed to conduct the above tests.  During this time the Argentometric
method outlined in Standard Methods was used, where interferences from
orthophosphate and iron were handled by special reagents as outlined in
the procedure.  There were no major changes in magnitudes when the
Standard Method* s procedure was substituted for the Hach kit, indicating
the relative reliability of the Hach kit results.

     NITROGEN AND PHOSPHORUS:  Total nitrogen was determined using the
Kjeldahl procedure.  Total, ortho-, and soluble phosphates were determined
using the stannous chloride method.  Both procedures are outlined in
Standard Methods.

     BIOCHEMICAL OXYGEN DEMAND:  BOD tests were run during the early part
of the study according to procedures outlined in Standard Methods.  However,
because of high dilutions required (usually greater than 1/20,000) the re-
sults were not very reproducible.  Because of this difficulty, seeding
problems, and other reasons, the BOD test was abandoned and not used as an
indicator of organic material concentrations.

Gas Sampling and Testing:

                        Gas Probe Construction

     Gas sampling probes were installed in cells 1, 2, 3, 7, 8, 10, 11, 12,
14, 16, 18, 21 and 22 at depths of 1, 3, and 5 ft. from the surface using a
post hole digger.  The probes were constructed of 1/4 in. I.D. rubber hose,

                                   168

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plastic funnels with 4 in. diameter tips, and galvanized screen.  Each  funnel
was inserted in rubber tubing and secured by wrapping wire around the con-
nection.  Galvanized screen was bent around the open funnel to prevent  it
from being clogged with refuse.

     This assembly was inserted in the holes and the refuse replaced and
packed down.  The projecting end of the rubber tubing was stoppered with
a rubber cork to prevent contamination of the gas in the tube by the
atmosphere.

                           Sampling Procedure

     Gas samples were collected using 100-ml gas collecting flasks, a trap
flask, vacuum pump and a portable generator.  Using a vacuum of 5 psi,  the
pump was run for 30 sec. to insure that the gas flasks were evacuated and
that gas from within -the cell was being collected.  Special tests led to
this as the best sampling procedure.

                          Laboratory  Analysis

     Gas analyses were conducted using a Fisher gas partitioner, Model  25V,
with helium as the carrier gas and a gas flow rate of 80 ml/min,

                         Results and Discussion

Theoretical Basis for Discussion:

     A simple water budget at the surface of a refuse cell indicates that
incident precipitation can leave the surface as runoff, be directly evapo-
transpired to the atmosphere, or infiltrate downward into the cell.  Water
which infiltrates will increase the moisture content of the surface layer
until that layer can hold no more moisture, whereupon the addition of more
water will saturate the next lower layer, etc.  As the process continues,
more and more of the cover soil or refuse becomes saturated until the
entire cell mass can hold no more water.  At this point, more infiltrate
will theoretically add more water than the refuse and soil can hold, and
a like amount of water will be displaced from the cell.  This water is  de-
fined as leachate, as discussed in an earlier section of this report.
Refuse or soil which can hold no more water is said to be at field capacity.

     It is apparent that the amount of leachate generated once field capacity
has been reached as well as the precipitation necessary to reach field  cap-
acity are both functions of the water budget at the top surface of a refuse
cell.  If the cell is covered with anything but properly sloped, impermeable
clays and fine silts, there is some infiltration in humid climates.  (This
must be so, otherwise many parts of the county would have little or no  ground
water replenishment.)  With milled refuse in the absence of cover, it may
logically be predicted that there will be little runoff, but increased  amounts
of evaporation when compared with reasonably fine soils as fine sands,  loams,
silts, etc.

     The goals of this study include the determination of whether leachate
is produced under Madison's climatic conditions and use of cover soils.  This
                                    169

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was to be done both for unprocessed compacted refuse covered with compacted
soil, as in a sanitary landfill, and for milled compacted refuse without
cover.  The cover soil to be used, when required, was the same as that used
locally at sanitary landfills.  In addition, leachate quality was to be evalu-
ated to assess the danger this material presents to ground and surface waters,
and to better understand the decomposition taking place in the two basic cell
constructions.

Leachate:

     First it must be stated that leachate was indeed produced by both un-
processed and milled cells.  However, direct comparisons of leachate data
from the various cells is difficult because the cells differed from one
another in size and shape.  Indeed, even within a given cell the leachate
produced represents only that collected by the tarp and not the total pro-
duction of the cell.  This is because the tarp underlies only part of each
cell.  Thus, different amounts of leachate were collected from cell to cell,
and the actual amount collected from each cell may not be representative of
that cell's entire production.  Because of this, a determination of the
water budget, or a presentation of data in terms of volumes of leachate pro-
duced per volume or weight of refuse, cannot be made.  For these reasons,
only the general shapes of the leachate volume and related curves will be
considered.  Note that exceptions to this rule exist only when considering
concentrations, where the leachate collected may be assumed to be comparable
to that generated over the entire cell.

     One problem observed in considering only the COD concentration of
leachate is that, on occasion, samples containing high COD concentrations
were collected at times when very little leachate was produced.  Throughout
the study, therefore, COD values in terms of grams of COD produced per
sampling period were obtained by multiplying the COD concentration by the
volume of leachate produced.  Curves of grams of COD produced provide a
more realistic display of the effect of the cells on the environment because
they indicate the total amount of matter which must be degraded to a non-
oxygen-demanding state.  Because only a portion of the leachate volume
produced was collected for study, these curves are only indications of
the total grams of COD produced in each cell.  Thus, the shapes of the
curves are useful, although the actual numbers should not be compared.
It should be noted that multiplying the two parameters together tends
to dampen extreme fluctuations in either leachate volume or COD con-
centration.

     Curves of conductivity are shown to indicate the concentration of
dissolved inorganic matter present in leachate at different stages of
refuse decomposition.  It was found that generally the conductivity and
COD curves were similarly shaped, although notable differences occurred
with refuse cells of different compositions.

     Other tests run included alkalinity, calcium and total hardness.
Graphs of these curves are not shown here, for it was noted that they
follow closely the shape of the conductivity curves which are, after all,
gross indicators of the sum of the concentrations of these and all other
ions.  The reader is referred to Table 48 which shows minimum, maximum, and
                                    170

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                                    TABLE 48

         Maximum,  Minimum,  and Average Values of Various Specific Ions
TOTAL HARDNESS - MG/L @CaCO,

Cell No.   Cell Type
Maximum
2
3
5
6
7
8
12
14
MCR
MCR
MG
UG
MR
UR
UCR
UCR
CALCIUM HARDNESS - MG/L
2
3
5
6
7
8
12
14
ALKALINITY

2
3
5
6
7
8
12
14
MCR
MCR
MG
UG
MR
UR
UCR
UCR
- MG/L @CaCO

MCR
MCR
MG
UG
MR
UR
UCR
UCR
9138
9988
11050
6250
710
1830
4940
6660
@CaCO 2
3420
2295
5950
2560
580
894
3060
3760

3
8200
6900
16100
14800
797
1765
6580
10105
7/9/68
6/27/68
3/1/69
4/8/69
3/1/70
8/4/69
8/4/69
10/23/69

5/12/70
7/11/69
7/11/69
5/12/70
3/1/71
8/4/69
8/4/69
10/23/69


7/9/68
6/27/68
6/27/68
10/19/68
4/5/71
6/13/69
10/23/69
10/23/69
Minimum    Average   Tendency
600
430
400
925
162
820
1198
680
239
203
256
137
102
342
427
1530
705
207
336
1926
68
496
579
1310
7/8/71
4/5/71
8/10/71
11/2/71
10/23/69
8/3/70
3/6/70
10/19/68
1/26/70
1/26/70
4/3/70
12/4/69
10/23/69
4/3/70
3/6/70
7/11/69
7/8/71
3/6/70
8/3/70
11/2/71
10/23/69
4/3/70
3/6/70
4/8/69
2317
1647
3135
3317
376
1181
2553
3081
857
616
974
1040
332
543
1765
2630
2544
1388
4795
9686
461
1064
2601
3511
                                                                               0
                                                                               0
                                                                               0
                                                                               0
                                                                               0
  + Implies that the curve slopes generally upward; 0 implies no tendency to rise
 or fall; - implies that the curve slopes generally downward.

"  Tests of Calcium hardness begun on 7/11/69.
                                        171

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Cell No.   Cell Type

CHLORIDES - MG/L @C1~
   TABLE 48(Cont'd.)

Maximum               Minimum    Average
2
3
5
6
7
8
12
14

TOTAL
2
3
5
6
7
8
12
14
TOTAL
2
3
5
6
7
8
12
14

TOTAL
2
3
5
6
7
8
12
14
MCR
MCR
MG
UG
MR
UR
UCR
UCR
A
IRON - MG/L @Fe
MCR
MCR
MG
UG
MR
UR
UCR
UCR
NITROGEN
MCR
MCR
MG
UG
MR
UR
UCR
UCR
q
PHOSPHATE
MCR
MCR
MG
UG
MR
UR
UCR
UCR
970
545
3636
3030
61
462
879
2000
950
143
103
318
91
283
173
304
353
4200
4000
201
134
800
625
18.9
18.3
99
122
24
4.9
11
6/8/70
10/23/69
3/1/69
12/16/70
7/6/70
6/13/69
8/4/69
5/12/70
5/12/70
7/6/70
2/2/71
7/6/70
6/8/70
9/29/70
5/12/70
8/3/70
1/28/69
7/30/68
10/19/68
7/6/70
4/8/69
10/19/68
9/4/68
1/27/70
7/6/70
2/2/71
8/21/70
6/8/70
6/8/70
3/6/70
118
2
35
818
700
106
152
303
1.2
9.1
2.6
15
2.2
43
120

13
5
0.7
44
1.6
20
49
263
0.2
1.8
1.0
14
0.2
2.6
6.2
11/2/71
3/1/71
9/6/71
3/1/71
10/28/70
10/28/70
3/6/70
7/11/69
1/6/72
11/30/71
8/9/71
8/9/71
10/5/71
12/16/70
4/3/70

1/6/72
5/5/71
11/30/71
1/6/72
11/30/71
3/6/70
3/6/70
12/4/69
11/30/71
4/6/71
11/30/71
7/8/71
11/30/71
12/16/70
5/12/70
475
116
626
1638
16
276
513
948
152
42
17
111
28
210
*
*
115
70
922
1732
45
64
374
430
13
7.4
34
55
5.8
2.6
*
*
Tendency
                                                                               0
                                                                               0
                                                                               *
                                                                               *
                                                                               *
  Tests of Chloride begun on 3/1/69.
4 Tests begun on 1/27/70.  Data for Cell 12 for 6 months only, for Cell 8 for
  1970 only, and no data available for Cell 14.
  Tests run prior to 1970 not considered.
                                         172

-------
average values for these and other tests.  Minimum, maximum,  and  average
values are also given for total phosphorus and nitrogen to give the reader
a feeling for their magnitudes.
     The final test was pH, the results of which revealed generally an
inverse relation between the pH and the COD concentration curves.  pH
curves are shown for the combined refuse cells to  illustrate  the  relation-
ship with the COD curves.

     To aid the reader in interpreting the graphs  and figures, the following
code will be used.  A blank space indicates that there could  have been a
point at some level within the gap but none was obtained due  to human error
or equipment malfunction.  The dashed line normally indicates an  actual
sampling attempt, but no sample was obtained  (e.g., no leachate present).

                   Unprocessed Combined Refuse Cells
                             Cell Histories

     Cells 4b, 12, 14 and 22 were constructed of unprocessed  combined refuse
and covered with 6 in. of soil to represent the normal sanitary landfill
situation.  Problems were encountered with leachate volumes in cell 4b; at
no time during the test period was it possible to  pump dry the leachate
reservoirs.  It is surmised that groundwater flowed into the  collection
system by some means, producing a virtually inexhaustible supply  of
"leachate" which had very low COD concentrations in comparison with the
other cells.  Cell 22 produced collectible leachate only after periods
of heavy rainfall; this suggested a leak in the collection system, allowing
most of the leachate to escape.  For these reasons, no meaningful conclusions
could be drawn from these two cells.

     Cells 12 and 14 seemed to operate satisfactorily until the entire
landfill was brought up to final grade in winter and spring of 1970.  The
cells were completely covered with other materials, precluding any further
study of them.   Cell 14 was affected in the winter of 1969-70 and cell 12
in spring of 1970.  At this time both cells started producing abnormally
large amounts of leachate.  The amounts were so large that it was impossible
to pump the reserviors dry, suggesting a general rise of the  water table in
the area.  All results from this point on were dropped from further consid-
eration.

                          Leachate Production

     Leachate production in liters per day is plotted on a time scale for
cells 12 and 14 in Figure 48. These curves show a slight but steady increase
in leachate volume from the onset of production, with seasonal and monthly
fluctuations superimposed on the curves.

     During the winter of 1969-70, no leachate was produced in either cell.
This is indicated by the dashed line on the curve  for cell 12.  (Note that
this is not shown on the curve for cell 14 since data for that cell were
not good from the winter of 1969-70 on and therefore was not  plotted.)
This lack of leachate was probably caused by an early frost with  little
snow cover until the month of January, along with  a general decrease in
temperature within the cells due to decreasing biological activity which
                                    173

-------
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             174

-------
allowed the cells to freeze.  This same phenomenon was experienced on
several of the other cells, as can be seen by their respective graphs.

                         COD Concentration

     The most prominent feature of the concentration curves for COD
for the unprocessed combined refuse cells, Figure 49, is the cyclic rise
and fall of the COD with time.  Closer examination shows that the peaks
and valleys of the curve seem to be affected by seasonal temperatures,
where peaks occur in the summer months and valleys in winter.

     Another characteristic of the unprocessed cells is the lack of
attenutation of the COD concentrations over the period studied.  With
cell 12 the COD concentration maintained a fairly constant level; whereas,
with cell 14, the COD values rose somewhat and then exhibited a slight
downward trend.  This seems to imply that, with the unprocessed cells,
the COD as expressed by concentration is released over a relatively long
period of time when compared with, for example, the milled refuse degrada-
tion results.

                           COD Production

     Over the period studies cells 12 and 14 both showed a gradual rise
in grams of COD produced per day (Figure 50).  The gradual release of COD
as mentioned above is more readily seen in this plot than in Figure
Note the relatively high initial production of COD grams/day as compared
to the rest of the curve.  This suggests that some readily leached organics
were present in the unprocessed combined refuse cells.

                Conductivity and Other Specific Ions

     With the unprocessed covered cells, the shapes of the conductivity
curves bear a resemblance to that of the COD concentration curves (Figure 51)
The seasonal rises and falls, for example, occur at approximately the same
times.  Also, a shape similar to the COD concentration curve is observed,
indicating that the inorganic compounds which comprise the conductivity
measurement are being released gradually over the test period.  Alkalinity,
chloride, and total and calcium hardness curves were of the same shape as
the conductivity curve and so are not shown here.  Maximum, minimum, and
average values are given for these and other parameters in Table 48.
Correlation coefficients were also determined and are given in Table 49.

                    Milled Combined Refuse Cells

                           Cell Histories

     Cells 2, 3, 9, 10, 11, 13, and 21 were constructed of milled refuse
and placed without cover during the 1967-68 period.  Of these, cells 9, 10,
11, 13, and 21 were destroyed or rendered useless due to factors beyond the
control of project personnel.  With cells 9 and 10, sod and soil were put
                                 175

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                 177

-------
                                     TABLE 49

       Correlation Coefficient For The Following Parameters Vs. Conductivity


Cell No.  Cell Type  Total Hardness  Calcium Hardness  Alkalinity  Chloride
2
3
5
6
7
8
12
14
MCR
MCR
MG
UG
MR
UR
UCR
UCR
.88
.98
.93
.45
.44
.74
.88
.77
.73
.91
.99
.39
.25
.85
.93
.75
.92
.98
.96
.74
.62
.87
.98
.68
.77
.65
.92
.65
.35
.80
.95
.97
NOTE:  1.0 means perfect correlation (i.e., variable varies linearly with
       conductivity); greater than 0.5 generally accepted as some correlation,
       less than 0.5 little correlation, 0.0 means no correlation at all.
                                        178

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                       179

-------
on the cells a year after construction, resulting in the leachate collection
systems being clogged with refuse dislodged by the heavy equipment.  Cell 13
was destroyed entirely by landfill operations which encroached upon and
finally covered the cell.

     For approximately one year cell 11 gave a constant volume of leachate,
after which it began producing more variable volumes.  This suggests that a
leak in the collection-reservoir system did not allow leachate to accumulate
beyond a certain level; thus the cell seemed to yield a constant volume of
leachate.  Somehow the leak became plugged, perhaps by sediment, after which
varying volumes of leachate were produced.  In any case this made cell 11
results somewhat less than satisfactory.  Cell 21 was destroyed in April 1970
while a fire which accidentally started in weeds on the cell was being
extinguished.

     This left cells 2 and 3 for analysis.  Approximately 3 years after
construction cell 3 was covered with 6 in. of soil; cell 2, however, has
remained virtually untouched for the entire test period.  The only un-
usual circumstance involving cell 2 occurred in April 1970.  At that time
it was doused with water while the fire which started on cell 21 was being
extinguished.  The fire briefly spread to cell 2.

                          Leachate Production

     Production of leachate from cell 3 was intermittent and very slow at
first, as shown in Figure 48. However, once the cell reached field capacity,
leachate was produced consistently until April 1970, when soil cover was
placed on the cell.  After that leachate production was again intermittent
and low in quantity.  The apparent slowdown of production in cell 3 was
probably caused by damage to the leachate collection system rather than
to the soil cover itself, although some reduction in leachate production
would naturally occur until the soil cover reached field capacity.  The
extent and timing of this decrease would depend on the runoff character-
istics of the soil.  Recorded field observations indicate that after the
cover was placed, trouble was encountered in sampling due to debris in
the sampling reservoir.

     Cell 2, which has been left without cover throughout the sampling
period, maintained a fairly constant rate of leachate production.  It is
interesting to note that the curves for cells 2 and 3 follow each other
quite closely during the 1969 sampling year, indicating that after field
capacity had been reached, the two cells reacted similarly.  The two curves
diverge after cell 3 was covered, with cell 2 continuing to produce approxi-
mately the same amount of leachate.

     As mentioned before cell 2 was doused with water during a firefighting
operation in spring 1970.  This shows up as part, if not all, of the con-
tinued high level of leachate production from April until June 1970.  The
production curve then begins to drop back to what appears to be its normal
level.
                           COD Centration

     The COD concentration curves for the milled refuse cells are shown  in
Figure 49. The most prominent features of these curves are the relatively

                                   180

-------
high initial COD values followed by a rapid reduction in concentration to
relatively constant and very low COD values of approximately 500 mg./l.  A
small rise in COD does occur in cells 2 and 3 in the spring and summer fol-
lowing onset of leachate production, but this is relatively insignificant
when compared with the general shape of the curve.

     With cell 2 one immediately notices the sharp peak in the curve during
summer 1970 for reasons mentioned above.  The relatively high rate of water
movement seemed to rinse more organics out of the cell than in the normal
case, resulting in higher COD values.  Two observations may be made as a.
result of this occurrance:  1) removal of organics from landfills could
possibly be accelerated by intermittent dousing with water and; 2) the
cell returned to normal conditions after the flood wave passed, as can be
seen by comparing COD and volume curves of both cells 2 and 3 before and
after the occurrence.

                           COD Production

     The curves indicating the grams of COD produced in the milled cells,
Figure 50, bear out the general characteristics of the COD concentration
curve in that there is a steady decline in the COD produced over the
period studied.  The high initial COD concentrations from the milled cells
are seen to be relatively unimportant when one considers the grams-of-COD
curve.  This is primarily because the initial volumes of leachate produced
were relatively low even though the COD concentrations were very high.  It
is noted, though, that more grams are produced early in each cell's history.

     Again with cell 2, the firefighting operation caused a sharp increase
in the curve.  However, the important consideration is that the curve re-
turned to normal conditions shortly thereafter.

                Conductivity and Other Specific Ions

     As with the unprocessed cells, conductivity has the general tendency
to follow the COD concentration curve but without dropping to the low levels
observed with COD.  The conductivity data are presented in Figure 51.  With
the milled refuse cells, this resulted in higher initial values followed by
a general decrease in magnitude to fairly constant and relatively low values.
Again there is the noticeable peak in the summer of 1970 on cell 2.

     Alkalinity and the other specified ions follow the shape of the COD
concentration curve closely.  Typical values for these parameters, along
with iron,  phosphorus and nitrogen, are given in Table 48.  Correlation co-
efficients relating various parameters with conductivity are given in
Table 49.  As has been mentioned previously and as shown on Figure 52, the
general shape of the pH curve was found to compare quite well in an in-
verse relationship with the COD and conductivity curves.

                       Special Garbage Cells

                           Cell Histories

     As mentioned previously,  two test cells were constructed using spe-
cially collected garbage (food wastes) and packaging along with other wastes


                                 181

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                                       182

-------
normally associated with garbage.  Cell 6 was constructed of unprocessed
garbage and covered with 6 in. of earth.  Cell 5 was constructed of milled
garbage.  Early in the study, leachate began to seep out the sides of cell  5
and rodent problems arose.  At this time the sides of the cell were covered
with earth; the top, however, was left uncovered.  It was hoped that these
cells would yield data on the effect of milling the garbage fraction of solid
waste with respect to degradation characteristics and landfilling properties.

               Leachate Production - Unprocessed Garbage

     Cell 6, the unprocessed garbage cell, began producing leachate in
relatively large and more consistent quantities than did the unprocessed
combined refuse cells, figure 53  gives the results for cell 6.  A higher
initial moisture content and lack of a significant paper fraction to re-
tard the downward flow of water by absorption in cell 6 probably accounts
for this difference.  For some unknown reason leachate production dropped
off approximately 1 year after this initial period and continued at a rela-
tively low level until it rose during the winter of 1971 to reach its
former level.

                COD Concentration - Unprocessed Garbage

     Curves presenting the.COD concentration for the special cells are
found in Figure 54. The unprocessed garbage cell produced more concentrated
leachate with respect to COD than did the unprocessed combined refuse cells.
The curve exhibited increases in the summer and decreases in the winter and
generally declined over the test period.  The gradual release of COD over
several years is again seen in the unprocessed cells.

     The higher COD values, approximately three times higher than obtained
with comparable refuse cells, are due to the increased amount of readily
available organic matter in the garbage cell.  This indicates the effect
of paper and other rubbish in depressing the COD curve.

                  GOD Production • Unprocessed Garbage

     The curves of grams COD per sampling period, Figure 55, exhibits the  same
shape as the COD concentration curve in that it starts out high initially but
falls to a low and fairly constant level toward the end of the observation
period.

       Conductivity and Other Specific Ions - Unprocessed Garbage

     The relationship between COD and conductivity is not as apparent with
with the garbage cells as it was for the combined refuse cells  (Figure 56).
With the unprocessed garbage cell, the conductivity curve generally in-
creased, whereas the COD concentration curve generally decreased over the
test period.  There is the tendency for seasonal peaks and valleys to occur,
but the general shapes of the curves are not as closely correlated as they
were in the case of the unprocessed combined refuse cells.

     As with the other cells, the remaining ion concentration curves follow
the conductivity curve very closely.  The curves are not presented, but
maximum, minimum, and average values are given in Table 48, and correlation
coefficients in Table 49.  In general, the pH varied inversely as the COD


                                    183

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concentration curve.  For Cell 5, the low pH value of 5.5 occurred on
July 11, August 4, and December 4 of 1967.  The high value of 7.5 occurred
on January 13, 1971.  The pH tended to rise over the test period.

                  Leachate Production - Milled Garbage

     With the milled garbage cell, as with the unprocessed garbage cell,
leachate production was higher when compared with the corresponding combined
refuse cell (Figure 53). Again, at least for the initial leachate production,
this was due to the higher initial moisture content of the garbage and the
absence of paper to absorb and thus retard the flow of water through the
cell.

     With the milled garbage there seemed to be a small but steady increase
in leachate production over the test period.  There did seem to be a greater
ease of leachate. production with this cell, with sharp peaks and valleys
resulting from wet and dry periods and other climatic variations.  This
points to the importance of the paper fraction to retard and thus dampen
the rate of passage of rain through cells until field capacity is reached.

                   COD Concentration - Milled Garbage

     The COD concentration curve of the milled garbage cell is not only
striking, but it seems to be particularly indicative of the milled cell
situation (Figure 54). The curve has a very rapid rise to a peak concentration
and then, just as rapidly, it drops to very low COD values, consistently
ranging around 200 mg./l.  In several samples, the low values of COD are
almost indistinguishable from zero on the plot.  These are among the lowest
COD levels found with any of the test cells.

     Most of the organics that decomposed and/or were leached from the
cell were removed during the early portions of the test period.  A compari-
son of the milled garbage curve to the curves of the milled combined refuse
cells suggests that most of the COD in leachate produced early in the de-
gradation process is a result of the presence of easily degraded organics -
the garbage fraction.  The milled combined refuse cells produced lower COD
values during this period because they contained less garbage (food waste)
than the milled garbage cell.  However, the non-garbage fraction present
in higher concentrations in the combined refuse cells seems to have had
the effect of retarding or prolonging the production of COD in leachate.
This may be accomplished by the presence of organic matter which is not so
readily degradable and which takes longer to leave the refuse as COD in
leachate, and by "diluting" the readily degraded garbage fraction.

                    COD Production - Milled Garbage

     The COD production curve shown in Figure  55, also indicates the ease of
degradation and/or leaching of the garbage fraction of solid waste.  There
is initially a rapid rise to a peak COD production rate followed by an
equally rapid decline to a small and virtually insignificant production
rate of COD.  This indicates again that the garbage fraction for milled
refuse contributes mainly to the early period of COD production and after
that it assumes an almost negligible role.
                                   188

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         Conductivity and Other Specific Ions - Milled  Garbage

     The conductivity curve for the milled garbage cell is shown in Figure  56.
It follows the shape of the COD concentration curve with high values followed
by reductions to low and rather constant levels.

     Again the other ion concentrations followed the conductivity curve
quite closely.  Summary data are given in Tables 48 and 49.   Also, the pH
curve was found to vary inversely with the COD concentration curve.  With
cell 6, the low pH value occurred on July 30 and October 19 of 1968, and
the high of 8.3 occurred on December 16, 1970.  In general pH rose during
the test period.

                         Special Rubbish Cells

                             Cell Histories

     Two cells were constructed using specially collected rubbish (combined
refuse without garbage).  Cell 8 was constructed of unprocessed rubbish and
covered with 6 in. of earth.  Cell 7 was constructed of milled rubbish and
was not covered.  Both cells were virtually free of outside influences
until the beginning of 1971, when sharp increases in leachate and COD
concentrations for cell 8 indicated the influence of the encroaching land-
fill operation.  Cell 8 is close to cells 12 and 14, which were similarly
affected the previous spring.

               Leachate Production - Unprocessed Rubbish

     Leachate production from the unprocessed rubbish cell, cell 8, began
several months after the rest of the test cells began producing leachate
regularly.  The data are presented in Figure 53.  When production did take
place it was initially at a low rate, followed by a gradual rise to the
point where outside influences affected the cell and negated any further
analysis  (early 1971).  A possible reason for the relatively late initia-
tion of leachate production is the cell construction date.  Cell 8 was con-
structed in March 1968, and so was one of the last cells built.  Because
it was composed of large amounts of paper, it took longer for the moisture
front to pass through the cell than with the other test cells.

                COD Concentration - Unprocessed Rubbish

     COD concentration levels from the unprocessed rubbish cell are low
when compared with unprocessed, combined refuse cells (Figure 54). This
corresponds with previous comments explaining the high initial COD levels
in the garbage cells, since rubbish contains less easily degradable organic
matter than either the garbage or combined refuse cells.  The COD curve
exhibits the characteristic seasonal fluctuations of the unprocessed cells.
The curve has a downward tendency after the peak which may be due to the
relatively hard-to-degrade organics present in large amounts in the rubbish.
What easily degraded organics there were in the rubbish were leached out
during the first peak, leaving relatively hard-to-degrade organics behind.
                                    189

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                  COD Production - Unprocessed Rubbish

     The gram-COD curve, Figure 55, exhibits the same characteristics as  the
COD concentration curve, with seasonal peaks and valleys plus a general
downward tendency.  Since leachate production is fairly consistent, the
low levels of production again point out the presence of the relatively
hard-to-degrade constituents of the rubbish fraction.

       Conductivity and Other Specific Ions - Unprocessed Rubbish

     The conductivity curve for the unprocessed rubbish cell, Figure 56,  was
found to correspond to the general shape of the COD concentration curve.
The curve exhibits the characteristic seasonal variations and the more
gradual decline in magnitude found with other unprocessed refuse cells
over the test period.  The conductivity range is lower than that of the
other unprocessed cells, again indicating the smaller contribution of the
rubbish fraction to pollutant production.

     The specific ion curves, as with the other cells, followed the general
shape of the conductivity curves.  The data are summarized in Tables 48 and
49.   The pH with the unprocessed rubbish cell was essentially neutral, al-
though a slight inverse relation with COD and conductivity could be detected.
The low pH of 6.5 occurred on August 21, 1970, and October 5, 1971.  The  high
of 7.7 occurred on October 19, 1968.

                  Leachate Production - Milled Rubbish

     Leachate production from the milled rubbish cell was very constant
except for the first point (Figure 53).  Initial production was slightly  higher
than production later in the test period; however, the decrease was so small
as to be virtually insignificant.

                   COD Concentration - Milled Rubbish

     The COD concentration curve, Figure 54, exhibits the initial peak seen
in the other milled cells, though the magnitude is very low compared with
the other cells.  COD production after the initial peak was so low as to
be almost nonexistent until approximately a year-and-one-half after pro-
duction began, when a second smaller COD rise occurred.  Second peaks were
experienced with all the milled cells but were not delayed as long after
the initial peak as in this cell.  This is again indicative of the poorer
degradation characteristic of the rubbish fraction of solid waste.

                     COD Production - Milled Rubbish

     The grams-of-COD curve is shown in Figure 55.. It follows the general
shape of the concentration curve.  Again the initial peak is followed by
secondary peaks.  Magnitudes of COD production are again very low when
compared with other cells, and the production decrease with time was not
as pronounced as with the milled garbage or combined refuse cells.

         Conductivity and Other Specific Ions - Milled Rubbish

     With the milled rubbish cell the direct relationship betx^een the con-
ductivity and COD concentration curves was not as pronouned as with the

                                   190

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other cells  (Figure 56).  The conductivity curve  had  a  slight  tendency to
increase throughout the test period, as opposed to the COD concentration
curve which generally decreased throughout the test period.

     The other specific ion concentration curves  usually exhibited level
or slightly downward tendencies.  The data are summarized in Tables  48 and
49 .  Correlation coefficients were, therefore, quite small with only  alka-
linity approaching significance in correlation with conductivity.  This is
because only the alkalinity curve showed an upward tendency as did the  con-
ductivity curve.  For the other variables the magnitudes of the values were
small and the differential changes with time were also so small that random
errors could easily have masked any relationships between the variable  in
question and conductivity.  As with the unprocessed rubbish cell, the  pH
curve is nearly neutral throughout the entire period, going slightly acidic
only during periods of COD rises.  The low pH of  6.0 on April 5, 1971, while
the high of 7.45 occurred on December 16, 1970.

Gas:

     Originally 13 cells were equipped with gas probes, but destruction of
cells by landfilling and fires reduced the number of cells useful for  long-
term gas data analyses to four.  These include cell 3 - milled and combined
refuse; cell 7 - milled rubbish; cell 8 - unprocessed rubbish; and cell 22 -
unprocessed combined refuse.  There was a period, indicated by the break  in
the curves, when the gas composition data were not collected.  This was done
in order to concentrate on the leachate data, as  there was some evidence
that gas composition was more dependent on the presence of cover than  on
whether the refuse was milled, and because early  gas results were so variable
that no trends could be established.

     Four gases were measured in terms of percent by volume of the gas
present.  These gases where Oo, ^2* CO?' anc* ^4'  ^s would be expected,
the 0  concentration was higher in the probes closer to the surface and the
CH/ concentration was higher at the deepest levels within the cells.  At all
depths sampled there was always a small concentration of Oo> probably  indi-
cating sampling or experimental error, since the  large CH/ concentrations
at the greater depths indicate anaerobic conditions.  For purposes of  this
discussion only the results from the probes at the greatest depths will be
given, as found in Figures 57 and 58.  Data from  other depths were superfluous
and compared well with the data shown here.

     In general, it is noted that 02 accounts for a larger percentage
earlier in the cells'  histories than later.  Likewise, CO  and CH. repre-
sent a smaller percentage in the earlier period than later.  This indi-
cates, in part, a change from aerobic to anaerobic conditions within the
cells.  Note again that the presence of some 0« at very low concentrations
is not thought to be significant, for small amounts of air were undoubted-
ly introduced during sampling and analysis.  TSU maY be determined by dif-
ference from the data given in the figures.

     C02 concentration, unlike that of the other  gases, did not fluctuate
quite as drastically over the test period.  Since C02 production should
rise as degradation increases, e.g., in the summer months, some CO^ gas
must be soluabilized into the leachate.  Further, since alkalinity is a
                                   191

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                           193

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measure of the ability of leachate to absorb acids, and since the alka-
linity was observed to increase during periods of increased degradation,
there is evidence that a possible increase in CO^ solubilization also
occurred during periods of increased activity.  This helps explain the
relatively constant CC^ concentration values observed in the gas analyses.

     It is also interesting to note that CC>2 concentrations seem to vary
much more widely in the two rubbish cells than in the two combined refuse
cells.  Since leachate production was lower, and leachate produced con-
tained less contaminants in the rubbish cells, it is possible that the
leachate produced in the rubbish cells was not sufficient to solubilize all
of the C0~ produced at all times, thus leading to the variation.

     Another interesting point with the gas curves begins with the observa-
tion that as the C^ percentage increases the CH* percentage decreases.
This occurred several times during the spring thaw and after periods of
heavy rainfall, indicating that 0- is carried into the cell by the percol-
ating water and retained in the cell for a short period of time.  This in-
hibits CH, production.

     Figure 57 indicates that the only major difference in gas composition
between cells 3 and 22 was the CH, content, which was markedly higher
in the case of cell 3 (milled, not covered).  This corresponds with the
leachate results, which indicate that milled refuse undergoes decomposition
more quickly.  There are no such marked differences between cells 7 and 8,
as shown on Figure 58, corresponding to the leachate results which indicated
that neither cell was undergoing rapid decomposition.

     A major problem in interpreting gas composition results was encountered
early in the study.  It was apparent that with most cells, the milled un-
covered cells had higher 02 and N2 concentrations and lower CH/ and CC^
concentrations than the unprocessed covered cells.  Unfortunately, the
data shown in Figures 57 and 58  do not show this because these data are
from the few cells which did not.  This general observation was difficult
to relate to the; leachate results, which indicated that the milled cells
decomposed more quickly.  The conclusion was that the presence of cover
may be of overriding importance, limiting passage of air in, and CC^ and
CH, out of, the cells.  The need for gas production data, as opposed to gas
concentration data, was the reason for the Biotron studies reported in Section
VI-C.  The lysitneter bed degradation studies, reported elsewhere, suggest
a similar conclusion with regard to the effect of soil cover on gas compo-
sition.

Apparent Mechanism of Decomposition:

     The data of this study illustrate some basic principles which can serve
to aid in understanding and interpreting the results.  The rate and extent
of degradation and the removal of matter from a landfill are dependent on
a variety of interrelated factors.  The two basic mechanisms resulting
in removal of matter are physical or chemical leaching and biological de-
composition.  Physical and chemical leaching is brought about by the flow
of water through refuse by which matter is rinsed or dissolved out.
                                    194

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Biological decomposition refers to the degradation of refuse to leachable
matter or gas by biological activity.  These two basic mechanisms are de-
pendent on the following:

     1.  Presence of water.

     Provided there is infiltration of water through the top layer
     of refuse or earth cover, as occurs in a humid climate, water
     will reach and wet the refuse.  Once the refuse can hold no
     more water and reaches field capacity, water flows downward
     through each successive layer of refuse and finally enters
     the underlying soil or the water table.  Such water is called
     leachate.  Water brings about physical and chemical leaching
     and, in addition, is a prerequisite for biological activity.
     As evidenced by cell 2, which received a large dose of water
     in the spring of 1970, physical leaching can remove large
     quantities of matter from apparently mature refuse volumes.

     2.  Temperature.

     Both the ambient or outdoor temperature, as well as the
     refuse temperature, affect the rate of decomposition.  The
     greater the temperature within the refuse, the more quickly
     biological activity proceeds.  The ambient temperature is
     important as it modifies the refuse temperature.

     3.  The presence of air.

     In the presence of air, aerobic decomposition takes place,
     which may be characterized by rapid activity, producing suf-
     ficient heat to raise the temperature perhaps 30 to 40° F
     above ambient at a 6 ft. depth.  If the rate of oxygen use
     exceeds the rate of replenishment, the refuse becomes
     anaerobic and a new group of organisms predominates.  At
     first organisms which can tolerate the presence of some
     oxygen become important, and these characteristically
     begin the anaerobic decomposition of the organic matter.
     In so doing, partially decomposed organics are made avail-
     able to the leachate, resulting in high COD levels.  Since
     some of these organics are acidic, the pH drops.  This is
     called first-stage anaerobic decomposition.

      As decomposition proceeds further and all oxygen is
     depleted, the methane-forming bacteria predominate.  These
     organisms are able to decompose organic matter more com-
     pletely to CH^ and C0~.  At this point the COD of the
     leachate decreases, the pH rises, and CH^ is actively
     produced.  This is called second-stage anaerobic decompo-
     sition and is commonly associated with little or no heat
     release or temperature rise.

     4.  The effect of milling and mixing.

     Milling is thought to enhance the rate of physical-chemical
     leaching and biological decomposition by increasing the


                                    195

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     surface area of the refuse, exposing more of it to biological
     and leaching activity, and by avoiding pockets of relative
     inactivity through mixing.  Further, water flows more evenly
     through the entire volume of refuse if it is milled, rather
     than channeling through and contacting only portions of the
     refuse as is more likely with unprocessed refuse.  This also
     brings about more uniform decomposition.  Finally, by breaking
     up large items such as cabbage heads, telephone books, etc.,
     during milling, the refuse can decompose more uniformly, so
     that a larger fraction of the readily removable, matter is
     extracted from all of the refuse quickly, leaving a relatively
     inert mass behind.

CONCLUSIONS

     The conclusions of this work, subject to the conditions and limita-
tions of the test cells, are as follows.

     1.  Organics were removed from milled refuse by leachate at a faster
rate and over a shorter period of time than with unprocessed refuse.  This
phenomenon resulted from the grinding and mixing of refuse, which produced
a product susceptible to uniform degradation and leaching.

     2.  The unprocessed cells were more influenced by seasonal changes
than were the milled cells.  Both types evidenced rises and falls in the
curves due to seasonal changes, but the unprocessed cells were more
strikingly affected.

     3.  Leachate production rates with milled cells seemed to be higher
when compared with the unprocessed cells.  This conclusion is tentative,
however, because an accurate water balance could not be made with the test
cells.  The change in leachate production is thought to be more a function
of cover than whether the refuse is milled.  The role of cover, however,
could not be determined in this study.

     4.  The pH curves showed an inverse relationship with COD concentration
and production curves, a relationship related to the two stage anaerobic
degradation process.  Initial pH levels for the milled cells were acidic
and rapidly approached neutrality.  In the unprocessed cells the pH curve
had a general trend toward lower (more acidic) pH levels with time.

     COD production curves for the milled cells showed an initial high
rate and then dropped off almost to zero.  With the unprocessed cells
the COD production curves began at a lower level than the milled cell
curves and then increased slightly or stayed constant in subsequent years.
Consequently, it was commonly observed that the milled cell produced COD
in leachate more actively than the unprocessed cell for one year or so,
while the comparable unprocessed cell produced larger amounts of COD than
the milled cell in subsequent years.

     These curves indicated that, for milled refuse, decomposition proceeds
more quickly and soon reaches a steady state level where few leachable sub-
stances are released.  During the initial high COD period, the low pH
suggests that aerobic and first-stage anaerobic decomposition is resulting
                                 196

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in partially decomposed and leachable  organic  substances,  including  organic
acids.  A few months later the pH rises  to near neutrality and  the COD  drops,
suggesting that second-stage anaerobic decomposition  is predominant, where
the organics, including the organic acids, are more completely  degraded,
and more CH^ is produced.  The general fall in the pH curves, and the rise
in the COD curves for the unprocessed  refuse cells, suggests that these cells
took longer to undergo decomposition and could not be characterized  as  having
attained mature second-stage anaerobic decomposition  to any great extent.

     5.  The conductivity curves show  that inorganics are  removed from
milled cells more quickly than from unprocessed cells, although the  difference
is not nearly as pronounced as in the  case of  COD.  Again,  milling and  mixing
seem to play an important role because the smaller particle sizes and the
more active decomposition processes expose the inorganics  to more leaching
action.  Conductivity and other specific ion curves generally followed  the
shapes of the related COD concentration  curves except in the case of the
special cells.

     6.  From the special cells the following  points  were  noted.  With  the
garbage cells, where readily decomposable organics were available, the  rate
of removal of organics by leachate from  the milled cell was much faster
than with the unprocessed cell.  Both  cells showed higher  concentrations
of organic matter than the comparable  combined refuse cells.  This is due
to the ready availability of organics.   The unprocessed cell showed  the
same tendency to undergo active leaching longer than  the milled cell, as
found with all other test cells, but never at  as high a level as the
milled cell during its peak production period.  The milled cell curve
shewed an extremely high level of COD  initially, but  dropped rapidly to
consistently low levels which were lower than  the unprocessed cell during
this period.  Both garbage cells dropped more  quickly to low COD levels
than did Comparable combined refuse and  rubbish cells.

     Leachate production from these cells fluctuated  widely, possibly
indicating the relative ease of passage  of water through the cell by the
dependency of leachate production on precipitation.

     Both the milled and the unprocessed rubbish cells produced relatively
insignificant amounts of oxygen-demanding substances  in the leachate.
This corresponds to the relatively small amounts of putrescible matter
present in the rubbish fraction of the solid waste used to construct the
test cells.  The low COD levels are especially striking when compared to
the garbage cell results.  The leachate  volume curves indicated a relatively
constant rate of production of leachate  from both cells, suggesting more
independence between leachate production and incident precipitation  than
found with combined refuse or garbage  cells.   This in turn suggests  that
the rubbish fraction served to retard  the free passage of  leachate through
the cell.  With both rubbish cells, the  production of contaminants in
leachate continued over a longer time  and at a more uniform rate than with
the garbage or combined refuse cells,  but at much lower concentrations.

     7.  Leaching played an important  role in  removal of organics from  the
cells, as evidenced by the dosing of cell 2 with water while a  nearby fire
was being extinguished, and also by the  overall shape of the milled  cell
curves.  In examining the COD production curves, one  can see an initial


                                   197

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high point of COD production which drops off  rapidly.  This  observation,
plus the rinsing of matter from cell 2, suggests that  some of  the  organic
material left in the cell after the peak is not fully  degraded,  but  simply
has not been rinsed out.

     8.  The gas composition data shows that  anaerobic degradation,  as
evidenced by increased amounts of methane, plays a  larger and  larger role
in the removal of organics as the cells mature.  Because of  the  nature  of
the test facility, it is not possible to compare the results from  the
milled and unprocessed cells, as the effects  of milling cannot be  separated
from those due to the cover.  For example, a  low CH^ level could be  due to
less CH/ production, or the ease of loss of CH, to  the. atmosphere  if no
cover is provided.  CC>2 data is not meaningful for  these same  reasons plus
the overriding effect of the solubility of COo in water.  Thus,  the  flow
of leachate may regulate the CC^ concentration more than any other factor.
                                    198

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VI-B - Lysimeter Field Studies

INTRODUCTION

      During review of the Olin Avenue decomposition studies, it was decided
that a more definitive analysis of certain characteristics of milled and
unprocessed refuse was needed.  Various problems unforeseen at the beginning
of the Olin project limited the conclusions that could be drawn from the data
obtained.  In the construction of the cells, for example, no attention
was paid to the size, shape, or amount of refuse in each cell.  This
meant that no results could be drawn as to leachate and/or pollutional
load produced by the refuse on a per-weight basis, and that no water flow
balance could be made.  Also, cells were not identically equipped with gas,
temperature, moisture, and leachate collection instrumentation and were
constructed at different times of the year; therefore direct comparisons
could not be made.  Finally, the ongoing operation of filling the surround-
ing landfill site covered several of the cells with refuse, precluding
further use of their data.  Initially this caused problems with one cell
but finally it meant termination of the entire project.

OBJECTIVES

      The primary objective of the lysimeter portion of the project was
therefore to isolate various refuse cells from the outside interferences
mentioned above.  With this accomplished, the second objective was to obtain
a direct comparison of pollutional loads from milled and unprocessed refuse.
Third, because of present regulations on the operation of sanitary landfills,
the effect of soil cover on degradation and pollution loads from refuse was
to be determined.  Finally, a water budget was kept to determine the per-
centages of precipitation which go to runoff, evaporation, and infiltration
(leachate).

LYSIMETER BEDS

Construction:

      With consent of the Oscar Mayer Company, two obsolete sludge-drying
beds at their waste treatment plant were converted to four test cells
(Figure 59).  The two beds, measuring 60 x 60 ft. with 1-ft. thick concrete
walls were excavated to a depth of approximately 5 ft.  The beds were
divided by wooden partitions to obtain a total of four cells.  A 4-in.
crushed stone base and 1-in, asphalt cover were sloped to the center of
the cells.  At the center a 24-in. vitrified clay pipe was inserted to
serve as a collection trap for leachate.  The spigot end of the pipe was
sealed with concrete and covered with epoxy paint to prevent any
chemical reactions with leachate from occurring.  An iron stormwater
manhole cover was then placed in the bell to support the refuse and
to prevent reaction with the leachate.  A plastic tarp was placed on
the asphalt floor and along all walls to insure leachate containment
and to further isolate the leachate from outside interferences (Figure
60).  Four inches of coarsely crushed granite rock (greater than 1 inch
                                  199

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in diameter) was then placed over the entire floor of the cells to
facilitate leachate travel to the collection trap and to prevent leachate
ponding in the cells.  Granite was used because lab tests conducted by
University of Wisconsin personnel indicated minimal interaction with
leachate.  A 2-in. polyvinyl chloride pipe was then inserted into the
clay leachate collection trap to a point somewhat above the proposed refuse
fill surfaces,,  This pipe was used to draw leachate from the collection
trap.  A 3/4-in. length of garden hose was also inserted into the collection
trap to the surface.

      Four cells (Figure 62) were filled, during the period September 14
to September 18, 1970, as follows:

          CELL 1 - unprocessed refuse covered with 6 in. of soil (Figure 63);

          CELL 2 - milled refuse covered with 6 in. of soil;

          CELL 3 - milled refuse covered with soil after approximately 6 mo.;

          CELL 4 - milled refuse left uncovered (Figure 64).

Each cell was filled with approximately 100 tons of refuse as specified
above.  About 75 tons of sand-clay cover of the kind used in Madison
landfills were placed on each of those cells requiring cover.

      The refuse and cover in the cells were emplaced and compacted by
tracked end loaders used in the city1s sanitary landfill operation.  The
surface on all cells was sloped at 3 percent grade to provide drainage
to the edges of the cells.  Rain gutters were placed along the periphery
of the cells to collect runoff.  A clear plastic tarp about 2 ft. wide
was placed along and slightly in the gutters and covered with either soil
or refuse to aid diversion of the runoff into the gutter and limit passage
of runoff around the gutter into the cell to show up mistakenly as leachate.

      The rain gutters were extended outside of the cells to a collection
and measuring point.  Here a 50-gal. barrel and 500-gal. tank were located.
The runoff was first directed into the barrel, which served as a more
accurate measuring device with smaller rainfalls.  With larger rain-
falls the runoff spilled over into the tank  (Figure 65).  These col-
lection vessels were calibrated so that depth measurements could be
converted to volumes.

      Besides leachate sampling collectors, probes were put into the
refuse cells to obtain data on gas production and cell temperature and
moisture.

Gas Probes:

      In the Olin Avenue study, gas sampling probes were made by using
inverted 4-in. diameter plastic funnels connected by rubber hoses to
                                 202

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the surface.  Trouble in sanoling some cells due to plugged funnels led to
an attempt to obtain a larger gas trap.  This was dons by taking a 10-qt.
galvanized pail and cuttim it in half.  The bottom half inverted in the
cell would serve as a larger reservoir.  The pail was covered with epoxy
paint to prevent possible leachate or gas reaction with the metal.  Holes
were drilled in the side and top to facilitate gas flow in and out so that
gas stratification could not occur in the trip and lead to erroneous results.
Crushed granite was then placed around the trap to prevent plugging of these
holes.  A rigid copper tube 6 in long was attached to the inverted bottom of
the pail on which a rubber hose was placed.  This hose was stoppered at tne
surface to prevent outside contamination.

2)  Temperature and Moisture Probes

     All temperature and moisture proules were provided by Soil Test Inc.
of Baraboo, l/isconsin.  In the Olin Avenue study the temperature portion
of the probes worked perfectly but the moisture portion seened to be
erratic.  Tin's was due in part to the fact that the probes ware being
used at moisture levels above their capabilities.  The Pact remained,
however, that no other probes were known to be capable of coping with the
situation.

     To calibrate these probles, they ,/ere placed in wire mesh boxes
filled with refuse and dunked in leachate until the refuse reached its
maximum moisture-holding capabilities.  The refuse-filled boxes were
gradually dried and periodical:/ weighed to calibrate the meter reading
as a function of the percent moisture.  Percent moisture was obtained as
the ratio of the weight of water to the weight of refuse.

     In analyzing the data the reader should be aware that the moisture
values as given are felt to be representative of the moisture content
range and not necessarily absolute values.  There are several reasons for
this.  First, these probes read conductivity, and conductivity changes in
the leachate could affect these readings.  Second, the probes undoubtedly
read moisture content at a point which may not reflect average ^oisture
content levels.  Finally, during calibration it was noticed that above a cer-
tain moisture level, t;i^ probes became insensitive.  In the case of cell /> t
for example, the probe readinos wore hinher than could be obtained during
calibration.  Thus the nrobe readings were not valid above a certain per-
cent, moisture, r.ri' the str?inht linn for the percent moisture plot results.1.
In spite of the a iovc difficulties, experience throughout the oroject indi-
cates that the average readings from replicate probes calibrate' in leadiotr
are guite reliable up to the maximum probe reading, and are especially
useful for tracini the movement ox the moisture front through refuse.

Probe Installation

     Temperature-moisture proves wore installed at three Jooths - G in. fro:.:
the bottom, mid-level, and (> in. fror. the tap of the refuse.  'Ins prcbes vers
installed at two depths - approximately a foot from the Bottom and r. noot fri.
the top.  .r '.nek hoe was used to dig n hole in the refuse t/j allow nrooe

                                    208

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 placement.   Refuse was then hand compacted as the probes were installed
 at  the  various  depths.  The probes were installed at the cell center to
 minimize  possible effects of the outside environment on data obtained.

      During the week of cell construction an analysis of Madison refuse
 on  a wet-weight basis was conducted by separating a total of one ton of
 refuse  from the packer trucks as they dumped at the milling site to see
 if  the  refuse was characteristic of solid waste as produced in other
 municipalities.  The analysis on a wet-weight basis is given in Appendix N.
PRELIMINARY DISCUSSION - THE DEGRADATION PROCESS

     The rate and extent of degradation, and the removal of organic matter
from a landfill, are dependent on a variety of interrelated factors.  The
two basic mechanisms resulting in removal of matter are physical and chnnical
leaching and hiological decomposition.  Physical and chemical leaching is
brought about by the flow of water through refuse by which matter is rinsed
or dissolved out.  Biological decomposition refers to the degradation of
refuse to Teachable matter or gas by biological activity.  These tv/o processes
are dependent on the following:

     1.  Presence of water.  Uater brings about physical and chemical Teaching
by the absorption of matter and, in addition, is a prerequisite for biological
activity.

     2.  Temperature.  Both ambient or outdoor temperature, and refuse
temperature, affoct the rate of decomposition.  The greater the temperature
within the refuse, the more quickly biological activity proceeds.  The
ambient temperature is important as it modifies the refuse temperature.

     3.  The presence of air.  In the presence of air, aerobic decomposition
takes place, which nay be characterized by rapid activity producing suffi-
cient heat to raise the temperature perhaps 30 to 40° F. above ambient within
the refuse.  If the rate of oxygen use exceeds the rate of replenishment,
the refuse becomes anaerobic and a new set of oroanisms predominates.  At
first organisms which can tolerate the presence of some oxygen become import-
ant; these organisms characteristically produce partial decomposition of trie
organic natter.  In so doing, partially decomposed organics are made avail-
able to the leacliate, resulting in hi Hi COO levels.  Since some of these
organics arc acidic, the nK drops.  This process is called first-stage
anaerobic deccnmosition.
     As decomposition proceeds further and all oxygen is deplete^, the .lethnn
forming bacteria predominate.  These organisms are able to Jecomoose ornanic
matter nore completely to C!!., C00, and M00.  At this point the COD of the
leachate decreases, the pH rises,""and CM*'"is actively produced.  This is
called second-stage anaerobic decomposition and is associated with little
or no 'icot release or temperature rise.

     •I.  T'io effect of milling and nixing.  Billing is thoinht to enhance
the rate of olr/sicc.1 and chemical leachino and biological decomposition b''
                                      209

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increasing the surface area of tiie refuse, exposing more of it to Diological
and leacfn'ng activity, and by avoiding pockets of relative inactivity through
mixing.  Also, water flows more evenly through the* entire volume of milled
refuse, rather than channeling through and contacting only portions of the
refuse which is not milled.  Finally, by breaking up large items as cabbage
heads, telephone books, etc., the refuse can decompose more uniformly, so
that nore of the readily removable natter is withdrawn from all  of the
refuse quickly, leaving a relatively inert mass behind.

Discussion of Oata Obtained fron Leachate Analysis:

     To aid the reader in interpreting the graphs and figures, the follow-
ing code will  be used.  A blank space indicates that there could have been
a point at some level within the gap but none was obtained due to human
error or equipment malfunction,  the dashed line normally indicates an actual
sampling attempt, but no sample was obtained (e.g. no leachate present).

The l-'ater Rudget:

     Precipitation incident on a ground surface is removed by three basic
"leans.  It can evaporate; it can move along the ground surface as runoff;
or it can infiltrate the ground surface and percolate downward.   Landfill
sites divide incident precipitation in the same manner, except the percolat-
ing water becomes known as leachate.  One of the objectives of this project
was to develop a v/ater budget - i.e., to learn what part of precipitation becomes
leachate, runoff, or evaporation for each of the various cells,   Measuring leach-
ate production, runoff, and precipitation are relatively easy; however, evapora-
tion is extremely difficult to measure.  For this reason, then,  the determina-
tion of a v/ater budget for the various cells involved obtaining  the percentage
of evaporation by subtracting the other two parameters from the  incident
precipitation.

Leachate Production:
      Figure 66 indicates the amount of leachate pumped from each test
lysimeter monthly throughout the test period, while Figures 3A and 3B
provide moisture probe readings within each lysimeter, at three depths.
Each reading is an average of values obtained from three replicate probes
(certain probes were not included in these averages because of obvious
inconsistencies).

                        General Observations
                             Field Capacity

     Precipitation which infiltrates into the surface of the refuse cell
•ioves downward into the cell and leaves at the bottom as loacfiate.  in orchr
to move downward in the absence o^ channgeling, the percolating water must
thorounhl'/ moisten each succ3erting layer much like water spreading in a
blotter.  In a refuse cell, liquid can spread down onl^ as long as there
is enougn moisture to keep the upper layers thorounhly soaked.  I/hen a
layer has reached the point whom it can no longer hold any niore water


                                    210

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          CELL 1 - UNPROCESSED.COVERED
          CELL 2-MILLED, COVERED
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                      COVERED 3/22/7I
      rr*
         CELL 4 -MILLED, NOT COVERED
       II II  I IT II I  II I Ml I  I I I  I I I  I I
      NDJ FMAMJJ ASONDJFMAMJ JASOND
         I     1971       I       1972
                    211

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but must pass along as nuch water as enters, the layer has reached field
capacity.

     Of course channeling can occur in the refuse cells '/hereby some
percolating water bypasses labors on its downward path, i.'Ut this amount
is snail compared to the amount of leachate produced when the cell reaches
field capacity.  It is thought that with unprocessed refuse the opportuni-
ties for channeling are much greater than with milled refuse because of the
more homogeneous character and degree of nixing obtained by milling.

     Hefore a refuse cell reaches field caoacity, leachate production
should IP m'nor and intermittant.  By observing the plotted graphs of leachate
production (Figure  66), just such a result can be seen.  In all cases early
leachate production is quite lo\/ when compered to later production, and with
cells 2 and 3 no leachate was produced during one samn'Mng interval.

     As the cell layers approach field capacity the moisture curves should
rise to a maximum point and level off barring long periods of drought or
intense rainfall.  The further down into the refuse the moisture content is
monitored, the more constant v/ill be the moisture content of a layer of refuse.
This effect is generally observed in Figures 67 & 68,   and especially in
Figure 68.  With all the cells at least some of the probes showed a rise to a
plateau just before, or shortly after, steady leachate production began.  With
other probes (especially cell 1 and 2) the moisture levels were already at
this plateau.

     Due to heavy rain during the week of filling the cells, the refuse in
all cells was exoosed to soaking.  Cells 1 and 2 in particular, constructed
at the beginning of tha wee!'., received considerable precipitation.  Though
the cells were covered by tarps overnight, the refuse absorbed moisture
during filling and also to some extent as it sat at curbside before collec-
tion.  Consequently these two cells should have had initially higher moisture
contents, which can be seen in tiie moisture curves.  It is interesting to
note that slightly higher leachate volumes were collected from cells 1 and
2 during the first two collection periods, again indicating a higher initial
moisture content.  In any case -i rise in moisture content precedes tha
attainment of field capacity, and this must occur before leachate is con-
sistently produced from refuse cells.

                         Effect of Spring Thai,1

     Another interesting observation with all cells was a noticeable rise in
leachato production during late winter and early spring, concurrent with the
spring thaw.  Higher and more consistent production occurred in spring both
years.  Also, the cells reached field capacity durinn the spring peak of tne
first year, indicating that snow melt aided the refuse in reaching field
capacity.


Cell 1 - The Unprocessed Covered Cell

     Besides those observations on leachate production discussed sarlier,

                                     212

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cell 1 showed a significant dropoff from spring thav; production to a rela-
tively lov; value during the summer months.  Production rose again in late
fall, indicative of effects from rains in September and October.  Leachate
production again dropped off over the mid-winter period due to lack of snow
melt, only to pic!' up again with the onset of the spring thaw.


Cells 2, 3, and 4 - The Milled Cells

     Since a primary objective of the project was to observe the  effect of
cover on nilled refuse, these three cells will be discussed together.
After reachinn field capacity, cell 4, the milled cell with no soil cover, uroducec
leachate at a rate higher than the unprocessed cell 1.  Drastic fluctuations in
leachate production fron nonth to month were observed with tin's cell's leachate
production, indicating that leachate production is highly dependent on incident
rainfall with milled uncovered cells.  Of course, extended periods of little
precipitation or larne anounts of precipitation tend to override these fluctua-
tions, as is seen in the spring thaws and in mid-winter periods.

     Coll 3 began producing leachate at a rate consistent with cell 4, as
would be expected since initially they were both uncovered.  However, in
'•arch 1971, 6 in. of soil cover were placed on this cell.  Compaction of
the cover on this cell resulted in squeezing out an abnormally large
amount of leachate for the April 1971 sampling period.  Production after
tfiis period commenced at a range much lower than that observed in cell &.
Of course some of this could be due to the soil cover absorbing water
before reaching field caoacity, but more importantly the soil serves to
promote more runoff than the  exposed milled refuse, which has a more
spongy texture.  Mi'th cell 3, then, leachate production becories similar
to that of cells 1 and 2, which were covered previously.

     Cell 2, the milled cell covered with soil immediately, exhibited leachate
production more closely following that of cell 1 from the start, with low
production rates in the sunnier, a small peak for fall rains, and a higher
peak for the spring thaw.

     Figure 69, sho^inn cumulative leachate production, more strikingly
illustrates the effect of soil cover on the milled cells.  The two cells
covered immediately (1 and 2) closely follow each other throughout the
sampling period.  Cell -1 shows a faster rate of cumulative leachate
production whereas cell 3 starts out quickly but si ones off to a rate
of production similar to cells 1 and 2.  This indicates that soil cover
indeed has a direct bearing on leachate production.

     The point at which the cells reached field capacity is very evident
in this curve.  It shows up as a sharp break in the curves durinq the
February-March 1071 interval.
                                     215

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Chemical Oxygen Demand Concentration - Ilg/L:

     The chemical oxygen demand, or CO;), is an indication of the amount
of oxygen required to chemically oxidize the matter in water.  As used
in this report, it may be considered a measure of the concentration of
organic substances present in leachate.  COD concentration curves are
given in Figure 70.

               General Observations - Winter Peak 'Of 1972

     In January and February of 1972 a substantial rise in COD concentra-
tion occurred.  This is especially noticeable in cell 2, and to a lesser
extent in cells 1 and 3.  Pell 4 had a negligible peak.  At the same time
in these cells the pi! curves dropped, as did temperatures and percent
methane (CH,), if any methane was present in the cell at the time.

     These incidents occurring at the same time suggest that the low
temperatures within the cells might have restricted bacterial activity.
Hith tin's occurrence refuse was not being degraded to as low an oxygen-
demanding state as before - thus the rise in COD concentration and
decrease in p[| due to failure to reduce organic acids present.  In cell
4, especially in the lower portion of the cell, the temperature was
usually slightly higher, so possibly the bacteria were not retarded to
as great an extent.


Cell 1  - The Unprocessed Covered Cell

     The C0[) concentration curve (Figure 70) shows a slight initial rise,
possibly indicating the releaso of some readily available  organics wnich
could easily be leached fron the refuse cell.  Winter produced a slight
decline in concentration followed by a pen!; during the spring thaw.  The
spring thaw indicates that the large volume of water, along with a rise
in terineratnre, aids biological and Teaching activity, thus bringing about
more substantial organic removal.  The summar months see a steadily declining
concentration of COU in the leachate.  This suggests that organisms are either
reducing the organic matter to a lower oxygen demanding state or that very
little organic natter is being removed in relation to the amount of leachate
passing throunh.  Later in this report, when the gas results for this cell
are presented, it will be observed that little or not methane is present at
this tinip.

     Again in the spring of 1972 the inordinately larqe amounts of w?ter
passing through the cell halp remove large amounts of organic matter, soine
of which possibly may not have been leached out otherwise.  Then, too,
increased biological activity with the spring warmth helps break down
matter so that it can be leached out even if the degradation orocess has
not reached final stages.
                                    217

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    CELL 1 - UNPROCESSED COVERED
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                     3/22/71
TIT III I TTT III I  M I  I I I I
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          1971        |      1972
                  218
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Cells 2, 3, and 4 - The Milled Cells

     Oata from the nlin Avenue project indicated that the typical milled
cell had a high initial peak COT foil over! by a rapid decline to relatively
small values thereafter.  A secondary peak usually occurred during the
following summer.  In the present study, cell 4, the milled cell left
uncovered, shows just such a curve (Figure 70). The curve also shows a high
initial COD value followed by a rapid dropoff prior to the rise to the peak
value.  This first high value may be due to squeezinn out moisture already
in the refuse by compactive effort, or to the lack of a mature biota to
modify the leachate composition.

     This same set of characteristics is observed with cell 3, except for
the longer duration of the initial COD peak and the hinder and longer
secondary peak in the winter and summer of 1972.  1,'ith cell 2 the initial
COD peak is of longer duration than in cell 3, and the mid-winter 1972 peak is
extremely hiah, even as high as the initial peak.  Further the second summer
peak (1972) is very pronounced and drawn out when compared with the second-
ary peaks of the other cells.

     Since all three cells are composed of milled refuse, the only differ-
ence between the cells is the presence or lack of soil cover, and the
timing of cover placement.  Since the same amount of organics (refuse)
are available for degradation and for leaching from each cell, this must
indicate an influen-e of cover on the degradation process.  Apparently,
with cell 4 conditions are more conducive to biological degradation,
followed in order by cells 3 and 2.  To repeat, cell 2 was covered with
soil immediately, cell 3 was covered six months after cell construction,
and cell 4 was loft uncovered.

     Examining other parameters such as moisture and temperature (Figures
68 and 69; 83 and 84)  the reader will notice that moisture conditions are
essentially the same in all 3 cells, whereas cell temperatures are some-
what hi'nhor in cell 4 than in the other two cells.  Cell 3 had tempera-
tures nucii like cell 4 until it was covered with soil and then the temper-
atures dropped off.  Leachate temperature(Figure 85), another indicator cT
biological activity, is higher wit!) the uncovered cell 4 than with the
other two.  Essentially, then, soil cover seems to result in lower cell
temperatures, retarding the degradation process and thereby releasing a
more concentrated leachate to the surrounding environment.  F'xtrapolatinc;
this assumption, one could surmise tint soil cover also olayeri a role in
retarding the degradation process in the unprocessed covered coll, a possibility
that is borne out by the data.  Finally, it is noted that tnis effect '^ay be
due to several nossible mechanisms, but one which seems particularly reason-
able in light of all of the daconposition results reported in this work is
the stabilization or treatment of leachate as it passes through a mature
refuse mass, under conditions conducive to biological, and oossible
chemical, activity.  Tho general shape of the COD concentration curve for a
milled uncovered cell, and the effect of dousing cell r in the 01 in Avenue
field degradation studies, are especially interesting in this regard.
                                    219

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Chemical Oxygen Demand Production - Grans/Day:

     It is obvious that the concentration of COD is not in itself of
great importance in its effect on the environment for a small amount of
leachate produced at a high COD concentration should be no worse than a
large volume of leachate at a much lower COD concentration.  For this rea-
son it is logical to calculate the actual amounts of chemical oxygen
demanding substances produced from a cell.  To obtain this value the
COD concentration is multiplied by the average volume of leachate pro-
duced per day between samplings to yield the grams of CHD produced per
day (Figure 71).

                          General Observations

     All cells initially showed very little total COD production since little
leachate was produced until cells reached field capacity.  Hith the spring
thaw and attainment of field capacity, substantial COD production began,
with faster production in the milled cells than in the unprocessed cell.,


Cell 1  - The Unprocessed Covered Cell

     Generally the COD production curve follows the COD concentration
curve with the exception that it is much smoother with no drastic fluctua-
tions.   There are three peaks in the curve:  two at spring thaws and one
at mid-summer.  These, of course, come at times of high COD concentration
or leachate production or a combination of both.  At other periods the
COD production occurs at a fairly constant pace.


Cells 2, 3, and 4 - The Hilled Cells

     In all cases the milled cells show a rise to a peak very quickly
after the cells reach field capacity.  From that point the production
curves  diverge.  Both cells 3 and 4 show broader initial peak envelopes indi-
cating that COD-producing organics are being removed from the cells quite rapidly.
It is interesting that ever after cover was placed on cell 3, these two curves
did not diverge significantly.  These two curves are more closely related than
any other two curves on the figure.  Cell 2, on the other hand, did not produce
as many grams of COO per day in its initial peak, but later on COD production
rates were higher than any of the other cells.  It should be noted here that
compaction of soil cover on cell 3 undoubtedly sqc^ezed out more grams of
COD than would be expected if the cell were left alone.

             Additlorjal Discussion of COD Production Curves

     The COD production curves indicate that the initial peak envelopes of
cells 3 and 4, which were then both uncovered, './ere of longer duration than
cell 2, but that later on the soil-covered cells produced more grams of COO
per day.  These phenomena can be explained by the nature of miller! refuse
and the effect of soil cover.  As explained previously, nillin^ refuse
exposes more? refuse surface area and, of course, produces fimr particle's.

                                    220

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              CELL 2-MILLED, COVERED
             I II I   I I I  I  I  I I I  I I  I I I
             FROM  6370 GR./DAY ON APRIL 5
               CELL 3-MILLED, COVERED
                              3/22/71
            CELL 4 - MILLED , NOT COVERED^
                                 TTTTII
     NDJFMAMJJASONDJFMAMJJASOND
             1971        I     1972       I
                     221

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Soil cover tends to recult in lower cell temperatures, aids runoff, anri
retards infiltration of water into the cells.

     This produces the following results.  In the cells without cover more
precipitation becomes leachate which removes initially more organic matter
from the cell.  Thus, more grams of COP per day are produced in the milled
cells without cover than in the milled cell covered with soil.  At the same
tine this increased amount of leachatr> tends to lower the COD concentration.

     As time goes on the greater amount of leachate in the uncovered milled
cell has less effect in grams of COD produced.  The   reason  why this
occurs may be that first, the more readily degradable matter had been
removed more quickly and uniformly from the milled refuse.  Second, a
mature biota brings about more complete degradation as  evidenced by
methane production in the cells (Figures 87 & 88).  This may be termed
second stage anaerobic degradation in which organics are degraded to a
low oxygen-demanding state.  This will be discussed in more detail later.
Third, the initial large amount of leachate may have v/ashed out organic
•-natter which may have stayed in the cell under lesser leachate flow
rates.

     i!ith the unprocessed cell 1, the organic matter narticle size is, of
course, much larger and the organic matter is not as well mixed as in the
milled cells.  Because this cell and cell 2 were both  covered immediately,
leachate production is on the same order as cell 2.  The result is that
less organic matter has a chance to be leached initially out of this cell
v/hen compared with the others.  With the smaller surface area of refuse
exposed in the unprocessed cell, degradation proceeds at a slower rate
than in the milled cells, and further, the soil cover slows the rate of
infiltration.

     A plot of cumulative COD production will possibly simplify the above
explanation (Figure 72).  All three milled cells produced more cumulative grams
of COD than the unprocessed cell.  The effect of soil cover on the milled
cells is to decrease the amount of infiltration which temporarily limits
the production of COD, but cover also nrolongs active degradation as
evidenced by the greater slope on the cell 2 curve than the cell 4 curve.
It is difficult to make any conclusions from the cell 3 COD production
curve.  There is the rapid rise in the curve which is more pronounced v/ith
this cell because of the placing of soil cover.  However, the long-term
effect of this soil cover was probably seen only in the last months of
recorded data.  It evidently took that long for the cell to recover from
the placement of cover and become stable.  According to the other results,
it might be predicted that the slope of th'> production curve will begin
to rise as degradation continues later in the deconnosition sequence.

     l!it!i coll 1, the unprocessed covered cell, there is a smaller rise
until field capacity is reached, egain indicating the smaller amount
of orqanics readily available for physical leaching,  "ftor this the
rate of production proceeds at a rate somewhat lower than cell 2 but
greater then the milled uncovered cell 4.  This suggests that the

                                    222

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  700
CO
5600
(T
U,
O
  500
CO
  400
CO

0300

H

  200
  100
    0
CELL  3

CELL 4
       NDJFMAMJJA
           I        1971
       FMAMJJASOND
              1972
        Figure 72.  Cumulative COD Production From Lysimeter
                  Test Cells
                           223

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curves for these two cells nay cross at a future time.   Also evident is
the fact that spring thaw, with its higher attendant leachate flow, does
not produce COD as rapidly with coll 1.

Conductivity:

     Conductivity, or more correctly specific conductance, is a measure
of the total  concentration of dissolved matter (largely inorganic ions)
present in the leachate.  Together with COD values, conductivity indicates
the total cross concentration of pollutants in leachate.   The conductivity data
are presented in Figure 73.

                          General  Observations
     The shapes of the conductivity curves somewhat resemble those of
the respective COP concentration curves to the extent that, as organic
natter is beinq directly leached or dissolved and removed bv the leachate,
so to is inorganic matter.  Biological  activity can affect conductivity
indirectly by changing pH and temperature but the effect is not so great
as with organic "natter.  Tins simply means that when organic concentrations
are reduced to lower values by biological activity, conductivity values are
not necessarily reduced proportionately.


Cell 1 - The Unprocessed Covered Cell

     The conductivity curve for the unprocessed cell fluctuates over a
fairly narrow range as compared to the  other three curves.  The curve
follows quite closely the shapa of the  COD concentration curve, a
characteristic noted in the 01 in Avenue studies.
Cells 2, 3, and 4 - The Milled Cells

     With the nil lied cells again, the conductivity curves resemble in
shape the COD concentration curves, with cell 2 showing the most simi-
larity and cell 4 the least.  Evidently soil cover has some bearing
on this.  Possibly with the attendant increased solubilization of
inorganic natter.  Then, too, with limited COD concentration values late
in the degradation process for cell 4, the pick-up by leachate of
inorganic matter, which is relatively unaffected by this degradation, would
still be produced in quantity.  !!ith the covered cell 2, where less rapid
degradation of organics is taking place due to a less satisfactory environ-
ment for biological activity, the later COD concentration values are higher
and fluctuate with seasonal temperature changes, incident precipitation, etc.
1'ith the more uniform degradation and/or release of the organics comes the
gradual release of some inorganics, and the fluctuations of the COD
concentration curve become more similar to those of the conductivity curve.
liote that this discussion concerning cell 2 is also applicable to cell 1.
                                    224

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  20
        CELL 1 -UNPROCESSED, COVERED
  10
  20
o
o 10

o
      CELL 2 - MILLED, COVERED
O
2
  20
       CELL 3 -MILLED,  COVERED 3/22/71
o
I
  10
20
     M I I  I I I  I I  Mill  I I I  I II I  III

     "  CELL 4 -MILLED, NOT COVERED
  10
     I I  I I  I I I  I I  I M I I  I M I I  I I  I I I  I M
     NDJ FMAMJJ  ASONDJFMAMJJASOND
        I     1971        I     1972     I
     Figure  73.  Conductivity of Leachate From Lysimeter
              Test Cells
                     225

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The Specific Ions:

     Conductivity is a measure of the ability of a  liquid  solution  to
carry an electric current, which is in turn related to the number and
type of ions contained in the solution.   Because of tnis close  relation-
ship, the curves of these specific ions  should resemble the conductivity
curve.  Analyses run for this study which measure the  presence  of these
ions are alkalinity, total and calcium hardness, chloride, iron,  and  to
a limited extent nitrogen, and phosphorus.  These curves are shown  primarily
for interest to document the magnitudes  and changes in magnitudes of  these
specific ions.

                               Alkalinity
     The alkalinity of water is a measure of the capacity  to neutralize acids
and is due primarily to salts of weak acids  such as  carbonates  and  phos-
phates.  Carbonates, of course, can be formed in the c'enradation  process.
The production of CO., during biological  degradation  can  give rise to
alkalinity in leachate directly depending on the degree  of basisity of
the refuse and the leach at??.

     In observing the alkalinity curves  of Figure 74, it is apparent that the
shapes of tiie curves do closely follow the respective conductivity  curves.
Thus the discussion concerning conductivity  will also apply hers.

                       Total and Calcium Hardness

     Hardness is caused by the nresence  of divalent  metallic cations,  where
calcium, magnesium, and iron are the principal  ones.  Calcium hardness is,
of course, a measure of the calcium cation,  a component  of total  hardness.
Hardness is a significant component of leachate in  that  in large  quantities
it can limit the usefulness of groundwater.   It is  of special  interest because
it is one of the components of leachate  which ras been shown to travel reason-
able distances through soils to degrade  groundwater.  Total and calcium
hardness curves (Figures  75  &  76  ) resemble their  respective conductivity/
curves.

                                Chlorides
     Chlorides are of significance in a study of refuse decomposition
because of their relative inability to be degraded or sorbed in passing
through refuse or soils.  In fact, they ara often used as  tracers  in ground-
water studies because of their inertness.  In sanitary landfills,  there-
fore, they can be used to indicate the extent to which the landfill  affects
surrounding groundwater, if base levels are known.  Further, because of their
inertness any chlorides arising from a landfill  will  likely join eventually
ground or surface waters, possibly influencing the quality of such waters.
the chloride curves, Figure 77, follow closoly the shapes of the conductivity
curves.
                                    226

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  10
 ro

O
O

o
        CELL 1-UNPROCESSED,COVERED
  10
 M I TTI I I  ITTM  I I I  I I I  I I

    CELL 2-MILLED, COVERED
 _
O


V)
Q 10
15
O
 M i M i  i i i  i M i  i i i  i M i i  ITrm

    CELL 3 -MILLED, COVERED 3/22/71
  10
_   CELL 4 -MILLED, COVERED
     I I  II II I  I I I  II  I II I II I II I  I II I
     NDJFMAMJJASONDJFMAMJJASOND
        I     1971        I     1972
    Figure 74.
          Alkalinity of Leachate From Lysimeter

          Test Cells

                 227

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  10
       CELL 1 - UNPROCESSED,COVERED
o
o
a
°
-I
v^
O
      i M i i i  ii iii ri n  irn MTI i  IT
       CELL   2 -MILLED, COVERED
I I  I I I  I I I  I I M I I  I I III I  ITTI I I

   CELL 3 -MILLED, COVERED 3/22/71
<
c/>
o
  10
TIT I  I I I l  I I I  I I I  I I I  I I I  I I I  I I I
   CELL  4  -MILLED, NOT COVERED
    I  I I I  I I M I  I I I I  I I I  I I I  I I I  I I I  I
    NDJFMAMJJASONDJFMAMJJASOND
       I     1971        |     1972       I
   Figure 75.  Total Hardness of Leachate  From LysiTieter
           Test Cells

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   10
 to 10
o
o
o
O
  10
o
o
   10
        CELL1- UNPROCESSED, COVERED
     II I  I II I IT I I  I I I II II I  I I  I I II I  I
   CELL 2-MILLED, COVERED
TI I TTI  II  II I  II II I  II I  II  I II II  I

   CELL 3-MILLED, COVERED  3/71/71"
I  I I  I I M I TIT T TIM  I M M  I I I  I I I

   CELL 4 - MILLED, NOT COVERED
       I I  I I I  I I II I  II I  M  Mil I  I II  I I I
     NDJ F MAM J J ASONDJ FMAM J JASOND

        '      1971         I       1972      I
     Figure 76.  Calcium Hardness of Leachate From Lysimeter
              Test Cells

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  20
  10
        CELL 1 -  UNPROCESSED, COVERED
  20
I  I I I  I I  I I I  II  I I I  I I I  I I  I I I  I ITT I


   CELL  2-MILLED, COVERED
-I
x

O
  10
o
LJ
a: 20
o
  10
Ml I  M II II I  I II  I I II I  I I I  I I  I I I

   CELL 3 -MILLED, COVERED 3/22/7I"
  20
M i i  i i  i M i M ITm i i  i i i  i i  M i

"   CELL 4-MILLED, NOT COVERED
  10
     MIT I III I  I I I  I I  I I I  I I I  I I  I I I  I
     NDJFMAMJJASONDJFMAMJJASOND

        I      I97I         I      I972
     Figure 77.
        Chloride Concentration of Leachate From

        Lysimeter Test Cells

               230

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                                  Iron

     The iron results are presented in Figure 78..  The curves are again seen
to follow the general shape of the respective conductivity curves.  The
iron curve of cell 4 is somewhat different in shape in that it drops off
faster, much like the total hardness curve, of which it (iron) is a
component.

     Iron is of special significance because it is frequently found in
groundwater and so is one component in leachate v/hich would seem to have
the ability to pass through soils, much like chlorides, without major
degrees of attenuation.  Further, the PHS drinking water standard limit
for iron is sufficiently low (0.3) ppm) that it may be of significance in
some localities.
     Mote that the iron content of leachate from
much higher than that from the unprocessed cell.
the exposure of nore iron to leachate in milled
paint remove! from cans, etc.

                           nitrogen Analysis
                             all of the milled cells is
                              This is thouqht to be due
                                         to
                            refuse by virtue of paper and
     Tv;o types of nitrogen v/ere studied extensively (Figure 79)-organic
nitrogen and ammonium nitrogen.  On several occasions nitrate-nitrite was
determined but with only few sanples, no significant data were obtained
but is indicated for information purposes only (Table 50 ).   Ammonium
nitrogen is the nitrogen that nxist.s as the ammonium ion, while organic
nitrogen is the nitrogen present as organic compounds.  The nresenca of
organic nitrogen usually means that ami no acids and polyneptides are
present, both of v/hich are products of the degradation of proteins.

                               Tablo 50

                jitrate-[
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  200
  100

  600
  500
  400
  300
  200
  100
o>
U-700
£600
 500
  300
  200
  100

  400
  300
  200
  100
         CELL 1 -UNPROCESSED, PROCESSED
I I  I I  I I  I
  CELL 2
           MILLED,
COVERED
      I  I II I I  I
           111 I  I I I  I I  | I II I  I I  I I I  I
             MILLED, COVERED  3/22/7J
CELL 3
        I  I I  I I  I I I  I IT Ml I  I II
          MILLED, NOT COVERED
      I  I I I  I I  I I I  I I  I I  I I I  I I  I I I  I I  I I I  I
      N  D J FMAMJJASONDJ FMAMJJ  ASOND
         I      I97I       I      I972       I
    Figure 78. iron Concentration in Leachate From
             Lysimeter Test Cells
                       232

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400
300
200
100
400
300
200
 100

500
400
300
200
 100

500
400
300
200
 100
       CELL 1 -UNPROCESSED.COVERED
                       DAMMONIUM  NITROGEN
                       o ORGANIC NITROGEN
        CELL 2-MILLED,COVERED
                  -MILLED, COVERED 3/22/7l_
                   -risMILLED, NOT COVERED-
     ITl I II II II I  I M I II I  II  II  I M I
    NDJ FMAMJJ ASONDJ FMAMJJ ASOND
        I     1971         I      1972        I
 Figure 79.  Ammonium and  Organic Nitrogen Concentrations
          of Leachate from Lysimeter Test Cells
                     233

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taking place.  '.Jith cells 1 and 2 degradation seems to ,iave occurred at a
relatively constant rate, since ornanic nitrogen occurs at a fairly con-
stant level.  This likely indicates that the degradation rate is less for
these cells than cells 3 or 4 during their peak degradation period.  Such
a conclusion supports the other leachate results.  With cells 3 and 4
the degradation seems to be stabilizing since production was at an initial
high peak and has dropped consistently to a level approximately one-half
of the peak value.  -It is likely that production of both ammonia and
organic nitrogen is degradation-dependent, giving substance to the
similarity of the shapes of the respective curves.

                           Phosphate Analysis

     Three phosphate analyses v/ere run:  total phosphate, total soluble
phosphate, and soluble orthophosphate,  The latter was discontinued in
December 1971 because of the similarity between it and total soluble
phosphate.  Total phosphate is defined as a measure of all forms of
phosphorus present in the wastewater.  Total soluble phosphate is that portion
of total  phosphate which passes through a 0.45 mm membrane filter as defined
in Standard Methods.  Soluble orthophosphate is that portign of total soluble
phosphate composed of compounds of f^PO,-, HPOA"2 and PO/"0.  The soluble
phosphate and orthophosphate values are of interest because the forms may
be expected to travel more readily through soils, if at all.

     In general all phosphate curves (Figures  80 and 81)   show a general down-
ward trend.  The milled cells show initially very high peaks followed by
rapid drop offs.  This indicates that phosphorus was rinsed from the cells or a
mature biota was formed after the peak which was able to take up some of the
phosphate and keep concentrations reduced after this point.  Probably it is
a combination of both.  It is interesting to note that initial peaks are
higher in the milled covered cell 2 than in the then-both-covered mi lie;1
cells 3 and < possibly indicating that the establishment of this biota
is not quite developed.

     Cell 1 does not show the initial high peak, but later data show phosphate
values somewhat higher with this cell than with the others.  This may
indicate that a nature biota has not teen produced to reduce the phosphate
levels.
     The pi! measurement (Figure 82) is of interest in analyzing data fron
refuse cells not only because it is an important characteristic of the
leachate composition, but because it can be used as an indication of
what type of deqradation process is occurring and what degradation products
are forming.  Thn discussion on dearadation in the COH section points out t'vit
once nature  anaerobic degradation occurs, tho ;•!! should risf to near neutral
levels,  lei die pi! levels ar? not considered optimal if degradation is to !"=
promoted, because of adverse effects or, many microorganisms.  Acid ;:!-' values
are obtained during the transition period :.ctween aeroMc ir' strictly
                                   234

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        CELL 1 -UNPROCESSED,  COVERED
              a TOTAL PHOSPHATE
              0 TOTAL SOLUBLE PHOSPHATE
                SOLUBLE ORTHOPHOSPHATE
      I I  I! HI I I  I M I  I II
               CELL  2-MILLED,  COVERED
   I-   \\
    N D J F MAM J J AS 0 N Dvj
       I       1971
FMAMJ JASOND
     1972
Figure 80.  Phosphate Analysis of Leachate From Lysimeter
          Test Cells (Cells 1 & 2)

                   235

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o
a.
_l
*^
o
   100
    90
    80
    70
    60
    50
    40
    3O
    20
    10
          CELL  3-MILLED, COVERED 3/22/1
                                         71
                   D TOTAL  PHOSPHATE
                   o TOTAL  SOLUBLE PHOSPHATEr
                     SOLUBLE ORTHOPHOSPHATE:
             CELL 4  - MILLED, NOT COVERED"
100
90
80
70
60
50
40
30
20
 10
       I  I I  I I  I
       NDJ  F MAMJ JASONDJFMAMJJASOND
          I       1971        I      1972         1
    Figure 81. Phosphate Analysis of Leachate From Lysimeter
             Test Cells  (Cells 3  & 4)
                       236

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o
h-
UJ
u
   8


   7
       CELL 1  - UNPROCESSED,COVERED
UJ
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8


7


6


5
       CELL 2 - MILLED , COVERED
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  I  I I  I I I  I I I I I  I I I  I I  I I I  II I  I I  I

    CELL 3-MILLED, COVERED  3/22/71
8


7


6


5
&jJ
     I I  ITT I I  Ml I I  I I I  I I I  I I  I I I  I I

       CELL 4-MILLED, NOT  COVERED
   8


   7


   6


   5
     II I I  I II  I I I  I I  I I I  I I I  M  I I M I I  I
     NDJFMAMJJASONDJFMAMJJASOND

        I      1971       I      1972        I

  Figure 82.  pH of Leachate From Lysimeter Test Cells

                    237

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anaerobic conditions, end also during aerobic conditions depending on
C9r,-H00 relationships.  The reader is referred to the COD section for
nore discussion of this subject.

Cell 1 - The Unprocessed Covered Cell

     The p.'i in tiie unprocessed, covered cell 1 has remained acidic.
This suggests that organic acids are beinn produced and that orqanics
arc not being reduced to their lovest oxygen-demanding state.  The fact
that methane gas is not being produced in this cell further confirms this
statement.  This is innortant Because it indicates t!i?.t degradation has not
been stabilized* to the deoree that either the refuse itself or the cie-
conposition processes have reached stable, relatively harmless conditions.
Mature anaerobic conditions will result in lower amounts of degradable
organics in leachate, and more products of decomposition leaving in the
gaseous phase.  Assuming gases are freely vented to the atmosphere, such
a condition should result in minimal environmental insult.

Cells 2, 3, and 4 - The "11 led Cells

     The striking effect of soil cover on the degradation process is
ojserver! with the pH data from the milled cells.  The covered cell 2
maintains an acidic pH, whereas the other two cells more closely  approach
neutrality.  The leachate from cell 4 has been less acidic than that from
any of the other cells.  Tnis, together with the fact that methane produc-
tion in cells 3 and 4 has begun, indicate triat the degradation process has
become relatively stable in these two cells.  This is further indicated by
the low COD being produced  in these cells during the last yaar or so of
monitorinn.  Cell 2 may have been approaching such a state in the fall of
1971, but the drop in cell temperature or other effects of the soil cover,
as discussed in the COD section, possibly set the process back by inhibitin'i
the methane bacteria.  Of interest is the fact that methane was observed
during.the fall of 1971 period but disappeared again and has been observed
only sporadically since. ,

Temperature:

     Temperature is of importance in the degradation process because it
directly affects the rate of biological activity and to a more limited
extent, the physical and chemical leaching processes.  The temperature
curves (Figures 83 & 84 ) show that soil cover has an effect on tempera-
ture as well as does the seasonal adiabatic temperature.

     Soil cover suppressed the temperature in the milled cells such that
with cell 2 the temperature curves fairly closely follow those for the
unprocessed cell 1.  "ithout soil cover the temperatures are initially
*Sawyer,  C.  N.,  and  P. L.  McCarty.   Chemistry  for  sanitary engineers
      2d ed.   New York, McGraw-Hill  Book  Company, 1967.  518 p.

                                   238

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     CELL1
              UNPROCESSE
                 OVERED
              I  I I  I I  I II II II  II  I I  I I  L

                  MILLED, COVERED     _
CELL 2-
              I! II M I   I   II  II  I   I I L
     CELL 3
         MILLED , COVERED 3/22/71
              UPPER PROBE
              MIDDLE PROBE
              LOWER PROBE
  I  I I  II  ||  I II I  I I I  I I  I I  I I  M  I I I  .
  NDJ  FMAMJJASONDJFMAMJJ ASOND
     I      1971          I      1972        i

Figure 83. Refuse Temperature in Lysimeter Test Cells
          (Cells 1, 2, and  3)
                 239

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            CELL 4-

        MILLED, NOT  COVERED
 1 1  I I  I  I I  I  I I  I  I  I I  I  I I  I  I I  I  I I  I  I I
 N D J FMAMJJASONDJFMAMJ  JASOND
           1971          I       1972
Figure 84.  Refuse Temperature in Lysimeter Test Cells (Cell 4)
                    240

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much higher and stay higher over a long period of time.  After tiiis initial
period in tne '.'inter season tanneratures in all cells are in much the sane
range.  In the following summer season, however, the covered cells again
are cooler.  Of interest is the fact that after being covered cell 3 reverts
fron a curve much like cell 4 to one Much like cells 1 and 2t indicating the
cooling effect of the soil cover.  Generally the top nnd Bottom temperature
probe curves cross the middle curves ?s the seasons change from winter to
summer and back, although with cells 3 and 4 this is not so consistently
the case.

     Leachate temperature data (Figure 85) further indicate the effect of
soil cover in lowering the temperature" of the cells.  The leachate tempera-
tures are lowest in covered cells.

     An interesting phenomena concerning soil cover rn^ cell temperature
occurred over the first two '-/inters of the project.  "Jurinn the first
v/intor nnrioc! 1 ^rge arens with no snov/ cover were prevalent on the then
both uncovered milled cells 3 and 4.   In contrast, on cells 1 and 2 snow
covered the cells all winter and ice patches occurred.  During tha second
v/inter only cell # had i'are notches though this './as not as prevalent as
during the previous './inter (note that cell 3 was covered with soil the
preceding summer).  Again the cells with soil had snow cover all v/inter,
and ice patches './ere more evident.

     In loo!. inn at the loach a to and cell temperature curves (Figures 83,
84,  and 85)   these temperatures are higher in cells 3 and 4 in the first
winter than the second, a fact which contributes to the snow melt.  In
the second winter, even though cell temperatures are much the same, the
lack of soil  cover in cell 4 must contribute to the bare spots on tin's
cell.  Thus soil cover must keep what heat is available insulated from
the snow, or must lower the amount of heat generated, or both.

Cell iloisture:

     As with cell temperature, soil cover has a direct effect on cell
moisture (Figures 67 and 68).  'Aside fror several minor fluctuations, the
moisture content generally increases with depth, but with soil cover the
difference in moisture between the upper and lower probes is reduced.
This indicates that for the milled uncovered cell 4, evaporation rates
are greater than in the other cells, where evaporation tends to pull
water upward to tiie cell surface for evaporation.  Soil cover, then, serves
to insulate the refuse from the sun, and drying by the atmosphere, thereby
maintaining a higher moisture level in the upper layers.  It seems that the
top refuse layer acts like a buffer zone, changing in moisture content over
a relatively large range, depending on climatic conditions.  In periods of
heavy rainfall, this layer becomes saturated and moisture flows downward
to bring underlying refuse to field capacity.  Conversely, in dry periods
the moisture in the ton layer is readily lost by evaporation from the
large exposed surface area (^aper, etc.) and some moisture migrates fron
lower depths bv capillary action to be evaporated at the surface.
                                   241

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b
LU
LU
IT
UJ
UJ
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    80 h
    70
    60
    50
    40
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80
70
60
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80
70
60
50
4O

80
70
60
50
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         CELL UNPROCESSED COVERED
          I 1  1 1  I
                   i  i l  i 1  i i  1 I  I I  l  i l  i i
                  CELL 2 MILLED  COVERED
          i i  i i  i i  i i  i i  i
                  i  i i  i i  i i  i i
CELL 3 MILLED, COVERED 3/ /7I
           i  i i  i i  i i  i i  i i
               i  i i  i i  i i  i i  i i
                CELL 4 MILLED,  NOT COVERED
        i  I l  i l  i i  i  i l  i l  l i  l i  i i  i i  i i  i i  i i
        NDJ FMAMJJASONDJFMAMJJ ASOND
     Figure 85.  Leachate Temperature From Lysimeter Test Cells
                       242

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Gas De.ta:

     Four qases were sampled for percent composition:  rL, CO   CH., and
00 (Figures 86 and 87).  Of these, Up is not plotted and can Be determined
b& difference.  Oxygen is present in all graphs.  Since methane is also pre-
sent on several of the nra^hs, indicating anaerobic conditions, it is felt
that sampling error contributed to the ubiquitous oxygen findings.  The
error was slight, hov/ever, since oxygen values were usually below 1 per-
cent.  It is interestinq to note that on occasion the percentages of
oxygen rose and in several cases stayed at relatively high percentages.
These rises usually occurred during or slightly after periods of high
precipitation or during soring thaws.  This indicates that water per-
colatinq through the cell possibly carried oxygen with it to the extent
that <\ '/as picked up by the qas probes.

Coll  1  - Ti:o Unprocessed Covered Cell

     The gas ddtr» for this cell, Figures 86 and 87 indicate little difference
between tiie upper and lower probes.  Perhaps this is due to ease of gas trars-
fer within the refuse in comparison with the nuch lower permeability through
the soil cover.  Another observation is that methane is, for all practical
purposes, not being produced in tin's cell.  This indicates that the decom-
position process has not stabilized tc the degree that the organic natter
in the refuse is being decomposed by second stage anaerobic processes.

     Also of interest is tho fact that the percentage of C00 is fairly constant
in the cell.  Observations from the Biotron studies (Sections VI-C) indicate that
CO, gas is absorbe.1 into laachate to a certain degree as carbonates, and shows
up^as al'calinity.  It is surmised that the curve is constant due to trie Tact
that C0n '.
-------
cn
o
QL
5
o
o
LJ
O
tr
UJ
a.
50
40
30
20
10

50
40
30
20
10

50
40
30
20
10

50
40
30
20
10
        CELL 1-UNPROCESSED, COVERED
                      -o- % C02
                      ~"°V
         CELL 2-MILLED, COVERED
CELL 3-MILLED, COVERED  3/22/71
         CELL 4-MILLED, NOT  COVERED
     NDJFMAMJJAS
            1971
                       M A M J J A SO N D
                           1972
  Figure 86. Gas Composition (Upper Probes) of Lysimeter
          Test Cells
                   244

-------
o
o
CL
O
O
LU
LU
GL
50
40
30
20
10

50
40
30
20
10

50
40
30
20
10

50
40
30
20
10
                CELL UNPROCESSED COVERED
                            «• 7o C02
                            •e- %  02
        I  I  I I  Inl—lotoi
       -  * WATER COLLECTED WITH SAMPLE
                CELL 2  MILLED, COVERED
* WATER COLLECTED WITH SAMPLE
   CELL 3 MILLED, COVERED 3/22/7
                 CELL 4, MILLED, NOT COVERED
        NDJ FMAMJ JASONDJ FMAMJ J ASOND
            I       1971          I       1972
      Figure  87.  Gas Composition (Lower Probes)  of Lysimeter
                Test Cells
                         245

-------
whereas, with cell 3 gas movement is retarded by the soil cover.  Thus,
the gas compositions measured are products of both gas transfer and gas
production factors, and must be interpreted in this light,  l/ith cell 2
little methane is produced so this effect of the coil  cover is not so
apparent.

     For the upper probes, the CO2 concentrations remain fairly steady
for cells 2 and 3 (as did cell 1), but fluctuate more for cell 4.  Further,
the fluctuations with cell 4 seem to be the inverse of 0,, level changes.
This may properly sugqest a relationship between C0? and 0^, which could be
the effect of large amounts of infiltration (rain or melting snow) bringing
in 09 and dissolving C00.  The fact that the C09 levels fluctuate more on
celT'4, and reached the^lowest C0? levels observed in this study, suggests
that the absence of cover resulted in more direct C00 loss to the atmos-
phere and dissolution in infiltrating waters.       '"

     The tendency toward lower C% concentrations in both the upper an'!
lower probes for cell 4 could be fin indication of less decomposition taking
place, but this is difficult to prove.  It is true that the more readily
decomposable matter is probably decomposed in the cell by the time the
drop in C00 is observed, and other evidence such as the leachate data
substantiates such a conclusion.  However, other factors such as the
pH and alkalinity of the leachate could also be causing this trend.

     The apparently increased 00 level in the lower probes of cells 2
and 3, in comparison with the upper probes, is difficult to explain.
The CH^i level was very low or zero when higher Go levels were reported,
as vouTcl be expected, which suggests that ana.lyttcal nroblenis were
not the cause.  As noted on the nreph water was collected with >% samples
on several occasions.  Tin's indicates thot high CU values at this1 tins "lay
due to the nresence of 0^ in the uater and not in the cell ner se.  It was
interesting to observe tfi?*: th*> water collected at these times was clear
in aonenrance.

The Hater 
-------
  220
0)200
£T
£ 180
  .60
   120
   100
   80
   60
   40
   20
   20
UJ
    .5
CO
Q
I
    10
        I I  I  i  I I  I  I I  I  I I  I  I I  I  I I  I  I I
                 CELL
        NDJ FMAMJJASONDJ FMAMJJ ASOND
           I         1971        I        1972
                           247

-------
shapes of the cells 1 and 2 runoff curves.
occurred at approximately the same times.
                                            The rises and level  portions
     Cell 4, the uncovered coll, had no runoff for a year.  In December of
1971, when the refuse at the top of tin's cell froze, some runoff was ob-
tained due to snow melt.  It v/as also observed at this time that the
refuse no longer looked simply like shredded paper but ''/as more solidified
like a coarse soil.  Deqradation effects had congealed the upper crust to
the point where it could carry some runoff water, but as observed this './as very
slight.  Mote that from this noint on runoff v/as occasionally produced, but
always at a lo"/ level compared with the three covered cells.

     Table 51 is composed of data obtained from May 1971 to May 1972.  This
period is used because by this time the cells seemed to have no more start-
up complications and reached relatively consistent performance.  Further,
all the cells had reached field capacity and were producing leachate regularly.
                                Table 51

              '•later Budget Over Period flay 1971 - .'lay 1972
Cell
Cell
Cell
Cell
           Precipitation
            (measured)
              Liters

              104200
              1 3-1200
              104200
              104?00
                             Runoff
                            (measured)
                           Liters
                          15150
                                      "*
  Leachate
 (measured)
Liters   %*
 Evaporation
(by difference)
Liters   ",'*
                          13677
                            233
14.5
15.1
13.1
0.3
190 IP,
17551
19249
23922
in. 2
16.?
1G.4
27.7
                 70112
                 70349
                 71281
                 74990
        67.3
        68.1
        68.5
        72.0
*Percont of precipitation.
     It is interesting that the evaooration percentages are nearly equal
        four cells, indicating that approximately 32 percent of
                                                         \
                                                                 :,-ie precipita-
fnr all
tion becomes runoff or leachato after field capacity has teen reached.  The
effect of cover iz to divide tin's 32 percent into approximately cnual per-
centages of leachate and runoff.
     Without soil cover a larger amount of precipitation infiltrates and
becomes leachato, while tLo evaporation rate increases slifhtly.  The
that evaporation rates are; ^higher in the uncovered cell could be predicted
by the fact that cell moisture probes Tor the upper layer of tin's cell indi-
cated that it VAS much drier than in the other cells.  It is projected tint,
as the surface texture of the uncovered cell 4 becomes more conncaled arid
soil -like, as mentioned, the runoff percentage should increase somewhat.
                                                                      fact
                                   248

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Conclusions:

     The following conclusions have been reached subject to the conditions
and limitations of this study.

     1.  Leachate production occurs at a faster rate in milled uncovered
cells than in covered cells whether they be milled or unprocessed.  The
rate of production is not a function of whether or not the refuse is
milled, but whether it is covered.  Soil cover reduced the fraction of
precipitation resulting in loachatc approximately in half.

     ?..  Soil cover either directly or indirectly served to keep the
refuse cooler, as evidenced by cell and leachate temperatures.

     3.  Soil cover drastically affected the rate and degree of degrada-
tion of milled refuse.  In the absence of cover a relatively mature
degradation system developed more quickly, which thus reduced the
organic pollutional load leaving the refuse in leachate.

     4.  Covering milled refuse after several  months of degradation
increased the noilutional loads in leachate, evidently by physically
squeezing natter out of the refuse during the application of cover.

     u.  Milling promotes degradation of a refuse cell whether cover is
present or not.  This is due to the increased homogeneity of milled
refuse and. the smaller particle sizes.  Thus infiltrate vets more
uniformly all of the refuse and promotes more uniform degradation of
the readily decomposable organic matter.  The result is rapid production
of partially degraded matter in leachate; leading to initially high
pollutant loads in leachate, followed in a relatively short time by the
onset of a mature degradation process, v;here fewer contaminants are
found in the loachate.

     6.  l.'ith the unprocessed cell, comparatively little of the readily
decomposable organic -natter is oxposad for rapid degradation and inter-
action with the leachate and channel inn of leachate through the refuse
can develop.  The result is lower contaminant production in leachate
initially, but continuing degradation at a moderate rate for an ox-
tended period.  Since it takes much longer for a mature anaerobic degradation
system to bo "'ovclopod, more partially degraded matter leaves the refuse as
contaminants in loaciiate.

     7.  Table 52  gives data on the production parameters of  each cell
   for the  first  22 months  since cell construction.
                                   249

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                               Table  52

              Production Parameters as of July 5, 197?
(actual production in units indicated and as percentage of cell  4 results)
Total Production

Leachate (Liters)
COD (Grans)
   Cell 1*

 29134  672
200753  52£
    Cell 2**

 29832   69%
437910  11 OS
    Cell 3***
Cell 4****
 35D51   33%   43336  7 032
571052  144%  397731  109"
^Unprocessed, covered immediately
**Milleri, covered immediately
***Milled, covered after f months
****f:illed, not covered
     ",  Data obtained from the water budnet analysis show that 68 percent
of the incident precipitation on the covered cells is evapotranspired to
the atmosphere.  The remaining 32 percent is alnost equally divided into
runoff and leachate.

     hn the uncovered milled cell somewhat more evaporation occurs such
that 72 percent of the incident precipitation is evapotranspired.   In
this case the larger part of the remaining 28 percent precipitation be-
comes leachate; only a minimal amount becomes runoff.

     ?.  Direct comparison of cell  1, the unprocessed covered cell, and
cell 4, the milled uncovered cell,  confirms conclusions  obtained from
the 01 in Avenue field study.  General curve shapes for the two types
of refuse cells are as previously obtained.  COD concentration curves
show a fairly constant level for cell 1  with fluctuations superimposed
due to seasonal chanqes; whereas for cell 4, the COD concentration
curve shows an immediate rise followed by a rapid drop to low and  relatively
consistent levels.  Again, as with  the Olin data, the two concentration
curves cross.  Initially cell 4 had COO levels approximately three times
those of cell 1.  After one year the COD values of cell  4 are less than
half those of cell 1.
                                    250

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VI-C - Biptron  Studies

      This section considers the changes in decomposition arising
when refuse is  milled and describes a study performed to provide
a direct comparison of the decomposition of milled and unprocessed
residential refuse without soil cover.

      Previous outdoor experiments have been undertaken in Madison
and other places to study  the degradation of landfilled refuse.
These experiments provided valuable data, but almost all had one
thing in common—unpredictable and  uncontrollable weather conditions.
Thus, this experiment was set up with two major objectives:   (1)  to
study the decomposition of refuse under controlled environmental
conditions , and (2)  to compare the degradation of milled and unprocessed
refuse of the same composition and under identical controlled conditions.

      The University of Wisconsin-Madison Biotron was used  for
the experiment. The Biotron is a unique research  institution that
provides facilities to do tests under closely controlled conditions.
It has several rooms  which can be programmed individually from
a central control. Parameters such as air  temperature, humidity,
and light can be varied according to a chosen pattern.

      This experiment was conducted in two identical compartments
in the Biotron—one for milled, the other for unprocessed refuse.
The arrangement made it possible to hold the refuse-filled cells
under identical conditions and, at the same time, to monitor the
degradation characteristics and pollutant production separately.
The controlled parameters also made  it possible to  select conditions
that would promote relatively rapid decomposition, thereby reducing
the time needed for the study.

      Data were collected from three main sources: (a) within
the refuse, (b)  from the leachate produced, and (c) from the gas
produced. Readings of temperature and moisture were taken.
Temperature data provided information about the biological activity,
while moisture  data made it possible to follow the water movements
within the cells.

      The following  tests were run on the leachate: pH , conductivity,
solids, hardness  (total and calcium) , alkalinity, chlorides, total
iron,  phosphorus (total,  soluble, and ortho) , nitrogen (ammonia
and organic) , and chemical oxygen demand (COD)  . Of the tests
                              251

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conducted, COD and total dissolved solids (TDS) are thought to
be the most important because they give a very good approximate
indication of the gross organic and inorganic contents, respectively,
of the leachate produced.  The tests were selected to give a detailed
picture of the pollution potential of leachate. In addition, they should
provide information about the degradation process.  It was also
of interest to study correlations between various parameters. The
chambers were supplied with a known and constant air flow.  The
exhaust air was analyzed for CC>2 and hydrocarbons.  Gas production
data should give information about the bacterial activity as well
as more precise data on total production of CO2 and hydrocarbons
from decomposing refuse.
EXPERIMENTAL SETUP

Description of Containers:

      Two similar containers, one filled with milled refuse, the
other unprocessed refuse, were used for the degradation studies.
The containers consisted of 3/4-in. plywood supported by a welded
steel frame. To make the containers  watertight, all joints and seams
were sealed with epoxy, two coats of marine varnish were applied
to the plywood, and two sheets of heavy polyethlene were used to
line the inside.

      Leachate was collected in the bottom of the containers, which
were sloped to a stainless steel pipe used as a drain.  The bottom
part of the containers was filled with 3/4-in. glass marbles to give
sufficient support for the overlying refuse and provide free passage
of leachate and finer solids while  preventing refuse from clogging
the drain.  Glass was used because it is relatively inert.
                              252

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      Rainfall was simulated in each container by a water sprinkler
system.  Even distribution of water over the entire surface at a
flow rate of less than one gal./min. was difficult, but seemed to
be obtained by using three spray nozzles. Distribution of the simulated
rainfall was  controlled by varying the rate of water flow.

      To maintain the densities determined after compaction, the
refuse was kept under pressure (Figure  90 ) .  This was accomplished
by placing a steel frame on top of the refuse and applying pressure
by a system  of four bolts. The middle bar of the frame was used
as a mount for the sprinkler system.
Refuse Composition:

      Composition data from an Environmental Protection Agency
survey of Madison refuse during the fall of 1970 were used as a
standard. (This is not the same survey as detailed in Appendix
 N.)   These data indicated that Madison refuse was close to national
averages , and it was thought to be desirable to use refuse of this
"typical" composition.  Since the experiment was started during
the winter, the refuse lacked grass and leaves. To correct the
deficiency, the percentages of the other organic components were
increased.  The "typical" composition and the target composition
for this study are shown in Table 53 .

      To obtain the target composition the refuse had to be sorted
by hand.  Several loads of residential refuse were separated into
the desired categories and the amount from each category needed
to fill a container was prepared using the target composition as
a guide.  Samples from both cells were made in the same manner.
The actual refuse composition obtained for the two cells is  shown
in Table  54  .
                              253

-------
f'%!!%. '^I?%I^ '••>&•'•

                kajfa '•* *  4i;* ••   k!
                ^^r •  *-"'•  ;*; ';^
                                              QJ
                                              •H
                                              CO

                                              C
                                              o
                                              !M
                                              4-i
                                              O
                                              •H
                                              C
                                              •H
0)
CO
D
                                              m
                                              Q)
                                              0)
                                             -H
                                             •r-i

                                             3:
                                              fO
                                              CD
                                              C
                                              -.H
                                              rO
                                              C
                                              CJ
                                             o
                                             01

-------
                  Table  53

"Typical"  and Target Composition  of Refuse
           (Biotron Experiment)
"Typical"
Component Composition
Paper
Cardboard
Wood, boards
Rags , cloth , leather
Garbage
Cans, metal
Bottles , glass , ceramics
Plastic
Grass , leaves
42.5
9.8
2.2
4.1
9.8
7.1
15.0
2.2
8.3
Target
Composition
46.61
11.00
2.47
4.62
11.00
7.10
15.00
2.20
0.0
                        100.0          100.0
                   255

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                            Table 54

        Actual Refuse Composition for Biotron Experiment
Component
Paper
Cardboard
Wood, board
Rags, cloth, leather
Garbage
Cans , metal
Bottles , glass , ceramics
Plastic
Milled Cell
45.09
10.65
2.37
4.45
10.50
8.08
16.36
2.50
Unprocessed
Cell
45.36
10.65
1.94
4.55
10.58
8.17
16.34
2.41
       Total                     100.00          100.00
       Average moisture on
       dry weight basis           14.9%           16.1%
      The milled sample was prepared using a Tollemache Hammer-
mill.  Several specimens were arbitrarily picked for determination
of moisture content. The average moisture content of the milled
specimens was 14.9 percent based on dry weight.  The unprocessed
sample was mixed and crushed by a rubber-tired front-end loader
to simulate landfill compaction.  The material not used in filling
the container was milled to get specimens for moisture determinations
The average moisture content of the unprocessed specimens was
16.1 percent.
                              256

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Filling and Compacting:

      The refuse was weighed and placed in the cells in layers.
Each layer was evened out and compacted somewhat by hand prior
to being compacted by machine.  A Universal Press capable of apply-
ing a load of 1,000,000 Ibs. was used to compact the refuse  (Figure 33
Loads applied by the press varied from 5,000 Ibs. on the first layer
to 10,000 Ibs. on the last layer.  These loads correspond to pressures
of 3.16 to 6.32 psi on the refuse surface.  (A medium size crawler
tractor will impose about 6 psi of pressure on the refuse surface.)

      To have a basis for comparison, equal weights and equal
volumes of refuse were placed in each container. To be able to
do this, the unprocessed refuse was crushed with a rubber-tired
front-end loader on a concrete base to break most of the bottles
and flatten the cans. (This usually does not happen in a landfill.)
Also, by hand filling the unprocessed cell, the larger articles were
selectively placed in each layer which, again, is not the case in
a normal landfill operation.  Data on weights and densities are given
in Table  55 .
                             Table 55

         Refuse Weights and Densities in the Containers
                      (Biotron Experiment)

                                               Unprocessed
      	Parameter	Milled Cell	Cell

       Total weight, Ibs.          1,190.8          1,263.4

       Dry weight,  Ibs .           1,038.0          1,088.0

       Density in place,
       Ibs./cu. yd.                584.0            644.0

       Dry density,
       Ibs./cu. yd.                509.0            554.0

       Depth of refuse, in.          54.0             53.0

       Volume of refuse,
       cu. yd.                      2.04             1.96
                              257

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      As shown, approximately the same weights and volumes were
installed in each container.  The densities obtained were lower
than expected and lower than normal landfill densities.  Reasons
for this were felt to be the very low moisture content, the fact that
no vibration was added as would occur in a landfill during compacting
by heavy equipment, and restrictions due to confinement of refuse
in a narrow container ("bridging") .  The densities of the two cells
were fairly close, as was intended.
Installation in the Biotron:

      The milled refuse container was installed in the Biotron on
February 4, 1971,  and the unprocessed container on February  5.
The containers were installed in two separate but similar compart-
ments with dimensions 8.40 x 3.95 ft. x 6.80 ft. high. Once in place,
they were wrapped in 3.5 in. of fiberglass insulation which covered
the outside from the floor to the top edge.  This was done to keep
the refuse under conditions similar to that which a volume of refuse
would experience in the middle of a landfill where, for example,
the lateral heat flow will be small compared to the vertical flow.

      The sprinkling  system was connected to the Biotron's system
of demineralized water.  The flow rate could be set to the desired
level using a rotameter.  Sprinkling was done at three different
flow rates:  0.45, 0.60, and 0.75 gals./min., respectively.  Sprinkling
intervals were chosen to give near equal amounts of water at each
flow rate. The drain pipe was connected by a tygon tube to a PVC
pipe that continued through the cabinet wall, thus allowing leachate
collection from the outside.

      After installation, the rooms were sealed to make them as
airtight as possible. The only air  circulation was through the  controlled
individual air system for each room.  The airflow through each room
was held at one cu. ft./hr. To provide a supply of clean air of
reasonably uniform composition, the air intake for the Biotron is
placed 40 ft.  above the ground and the air is passed through a  filter
to remove particles and an activated carbon filter to remove most
gas contaminants.

      The rooms were run on the same daily climatic conditions
throughout the experiment.  The temperature varied daily from 75°
F   (23 °C.) to 95°  F (35° C.) .   The simulated daylight lasted for
16 hrs. with  1/2 hr. dawn and twilight. The light system consisted
of twenty 200-watt fluorescent warm lights and three 500-watt incandescent
lights.  Air humidity was kept at a constant 80 percent.  Rainfall
occurred once a week, except for a period from June 11 to July 8
when the frequency was twice a week.  Total amount of "rain"  during
                              258

-------
the experiment was 65.77 in., which is equivalent to 87.9 in./yr.
The climatic condition was designed to approximate a hot summer
period with frequent rainfalls which would be expected to accelerate
decomposition.

      There were several reasons for not including  seasonal variations
in the climate.  Such variations would mean added complications
for data interpretation.  Furthermore, it was not an objective of
this experiment to study degradation under climatic  conditions similar
to any particular area.
DATA COLLECTION

      Three basic types of data were collected:   (a) temperature
and moisture data from within the refuse, (b) physical and chemical
analyses of the leachate, and (c) gas data from the exhaust air by
monitoring the CO2 and hydrocarbon content.

Temperature-Moisture Readings:

      Data on temperature and moisture were obtained from probes
installed in the refuse mass during filling and compaction. The
probes were placed in triplicate at three depths near the center
of each container, where care was taken not to place a piece of glass
or metal in contact with a probe.  In addition, three probes were
placed near the end walls.  All the wires from the probes were passed
through a special opening  in order to take readings from the outside.
Because of the filling technique used, it was impossible to determine
the exact position of the probes with respect to depth until the conclusion
of the experiment. At this point the probes  were dug out and their
location determined.

      The probes , Model MC360 Standard Moisture Cells, are manufactured
by Soiltest, Inc. Readings were taken with a Soiltest MC300A soil
moisture ohmmeter. Moisture determination is based on the resistance
between two metal plates in the probe.  Temperatures are obtained
by use of a thermocouple.  Although the probes were designed for
use in soil, they have been used in previous landfill experiments
and have been found to be  the best means available. Previous experience
has led to certain techniques for use of the probes in refuse, such
as wrapping them in asbestos,  using probes in triplicate, and using
a revised calibration method. However, even with these improvements ,
the probes are used only to indicate changes in the moisture content,
rather than absolute moisture values.

      The probes were calibrated prior to installation.  This was
done under conditions simulating  what they would experience in
the cell itself. The probes were held in cages made of metal screen
filled with a known amount of refuse. Moisture was added in the
                              259

-------
form of leachate.  Readings were taken at many different moisture
levels and the known moisture contents plotted against resistance
to give a calibration curve.  Temperatures could be determined
directly by use of a table.

      The probes seemed to give reasonable results for temperatures.
The differences between the probes in a triplicate set were typically
on the order of 1 to 4°  F  and the average value is thought to be
fairly accurate.  Moisture values were more variable.  In almost
all cases triplicate probes gave moisture content  results that differed
by 10 to 30 percent.  It was very difficult to detect whether these
differences were due to actual  local differences in moisture content
or errors in the probes because of special conditions.  The range
of moisture content in which the probes  gave reasonably reliable
results was 20 to 130 percent on a dry weight basis. The upper
limit may not cause problems for applications  in most soil, but in
refuse the moisture content will often exceed 130  percent. This
caused some problems  when determining the moisture content as
the refuse approached  field capacity.

      The typical sequence for moisture readings with any one
probe began with undetectably low readings.  After several weeks
(3 to 15 depending on the depth) readings went up quickly and,
in some cases, passed  the highest detectable level after one to three
additional weeks.  Quite naturally,  the largest differences between
the triplicate probes  occurred  during the period  of rapid  change
in moisture readings.  A  likely reason for this is that the moisture
front could reach each probe in a triplicate set at a different time,
for the probes were spread a few inches apart horizontally and up
to 1 in.  vertically.

      Temperature and moisture readings were taken twice a week
from the beginning of the experiment though June (21 weeks) .
Afterwards readings were taken once a week.  Typical curves relating
percent moisture and temperature versus time are shown  in Figures 91 and 92
A 12-hr. temperature study was conducted on August 5 to determine
whether the daily fluctuations  in air temperature affected the temperature
within the refuse.  Readings were  taken at 10: 00 a.m., 1: 00, 4: 00,
7: 00 and 10: 30 p.m.  No  daily  fluctuations could  be detected. The
insulation of the container could, therefore, be regarded  as sufficient.

Leachate Analysis:

      All the "rain" applied, less evaporation loss, had to be stored
in the refuse or appear as leachate. The frequency of leachate collection
was adjusted so that  the storage volume beneath the refuse was
not exceeded. This meant collection two to three times per week.
                              260

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      Leachate samples were taken twice a week, normally on Mondays
and Thursdays. It was impossible to run all tests on each sample
because of laboratory capacity.  The procedure used was to run
pH and conductivity on each sample, and to split the remaining tests
in two parts, running one-half of the tests on Monday's sample and
the remainder on Thursday's sample.  Later in the study (from August
5 to October 18)  it was found sufficient to run each test every other
week; therefore, all the tests were run on one sample from each
cell collected every other Monday,   During the last three weeks
of the experiment an  attempt was made to determine the effects of
increased rainfall on leachate quality.  The frequency  of sampling
was increased to once a week during this portion of the study.

      It was suspected that leachate quality could be related to the
length of time from the last "rainfall" to the  next sampling.   Therefore,
some additional tests (pH, conductivity,  arid COD) were run on
leachate samples collected the day after sprinkling and also on samples
collected one week after sprinkling but immediately before  the next
sprinkling.  For the milled cell no significant correlation could be
found between leachate quality and the time elapsed from last sprinkling.
For the unprocessed  cell,  however, it was found that COD and conductiv-
ity values were slightly lower in samples taken one day after sprinkling
than in samples taken immediately before the next sprinkling.
The results from four such tests showed  an  average reduction in
COD of 6.8 percent, and the  variation was from 4.5 to 8.7 percent.
Because of this, sampling  for analysis was generally done three
to four days after sprinkling.

      Leachate flowed by gravity from the container and was collected
in a 1,000 ml graduated cylinder to measure volume.  On days when
tests were to be  run, the sample was taken from the last one-third
of the total leachate volume collected.  This procedure was  felt to
give the most representative sample of fresh leachate.  The samples
were kept in 500 ml polyethylene bottles  or  300 ml glass bottles.
Acid washed glass  bottles  were used when phosphate arid iron analyses
were to be performed.

      Previous experience with leachate anatysis has indicated
that results will vary due to interferences being present which depend
on the amount of suspended matter in the sample. Furthermore,
the amount of suspended matter is a function of many uncontrollable
factors not necessarily related to the decomposition process. This
problem was overcome by  using a decanting technique. When a
sample was brought in, it  was shaken  and then left to settle. After
four hrs. the supernatant was decanted off.  All samples were treated
                              263

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         in the same way.  Data show that the samples after decanting were
         low and uniform in suspended solids. This procedure is felt to
         correspond to actual landfill conditions where most suspended matter
         will be filtered from  the leachate by passing through a few inches
         of soil.

               Normally, pH, conductivity, COD, alkalinity, and hardness
         were run on the day of collection.  In a few instances, they were
         run on the day after. The remaining tests were then run within
         a week of collection. The samples were stored in a refrigerator
         until analysis.

               The  methods of analysis for the various parameters followed
         Standard Methods*and were:

                     Chemical Oxygen Demand  (COD): Standard
                     Chloride:  Argentometric and Mercuric Chloride  Methods
                     Total Hardness:  EDTA Titrimetric
                     Total Iron:  Pehnanthroline
                     NH3 -   N and Organic N:  Micro - Kjeldahl
                     Phosphate:  Persulfate Digestion, Stannous Chloride
                     Alkalinity:  pH meter
                     Total Solids:  25 ml sample
                     Suspended Solids: Filtration of 25 ml sample

         Experience has shown that leachate is especially difficult to analyze.
         The reason is that leachate contains practically all elements in concentrations
         exceeding  levels found in most wastewaters.  This causes interference
         problems for some tests. In this experiment there were difficulties
         with the  chloride test, especially with leachate from the milled cell.
         The probable reason was interference from the high iron content
          (over 300 mg/1) . The phosphate analysis was also difficult to perform,
         especially  for soluble and ortho-phosphate.  Many of the difficulties
         were due to the strong color of the samples which tended to obscure
         the endpoint of the reaction used in the analysis.

               Since sample-handling procedures would lead to some aeration,
         a special test was performed to determine the effect of aeration on
         two of the analyses;  namely: pH and conductivity. One sample
         bottle was  filled carefully and capped.  Another sample was aerated
         by vigorous shaking in a half-full bottle and was left uncapped for
         several hours. No difference was detected between the two samples.
         It is unlikely that any of the other parameters used in this  experiment
         should be so much more  sensitive to  aeration than pH and conductivity
         as to invalidate the results .


*American  Public  Health   Association,  American Water  Works Association,
      and Water  Pollution Control  Federation.   Standard  methods for the
      examination  of  water  and waste water.   13th ed.   Washington,
      Publication  Office, American  Public  Health  Association,  1971. 874  p.


                                       264

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Gas Analysis:

      The chambers holding the refuse containers had separate
enclosed air systems ,  as described previously.   This arrangement
allowed independent analysis of the exhaust air from each chamber.
All gas analyses were done directly on samples from the exhaust
air pipe. Exhaust air was analyzed for CC>2 and hydrocarbons.
CO2 content was measured by a Beckman infrared analyzer, Model
IR315. Total hydrocarbons were measured as CH^ by a Beckman
hydrocarbon analyzer, Model 400.  All concentrations were given
in ppm by volume. The gas readings were done by the Biotron
staff.

      The air flow of one cu. ft./hr. was low enough to give detectable
increases in CC>2 and CH4 content and, yet, high enough to maintain
a near normal atmosphere in the rooms.  The rooms were kept under
a slightly positive pressure to avoid any inflow of air. Some difficulty
was experienced in getting good gas data. One problem was  fluctuations
in the composition of the supply air; therefore, the supply air was
analyzed as frequently as the exhaust air so that fairly accurate
ambient values could be established.  Other difficulties with the
gas analysis were related to the CH
-------
surplus water would penetrate deeper into the bed.  The main waterfront
thus moved downward as the refuse reached field capacity.  It is
likely that water reached locally further downward than the main
waterfront because of inhomogeneity in the refuse bed and the possibil-
ity of channeling.  In both cases, this is more likely to occur in
unprocessed than in milled refuse.  The tendency to channel will
increase with void size and unprocessed refuse will have larger
voids than milled.  Channeling and locally advanced moisture fronts
are the main reasons for leachate being produced before the whole
refuse mass has reached field capacity.

      The changes in moisture content were detected by moisture
probes placed in the refuse. The moisture data made it possible
to calculate the downward speed of the waterfront.   The presence
of the front was indicated when the moisture value from the first
sensing probe in a layer leveled off after a rapid rise.  Tables 56  and
57  contain data pertaining to the speed of the moisture fronts.
The average speed of the saturated front for the milled and unprocessed
cells was 0.50 and 0.658 in./day, respectively.  Average penetration
for the respective cells was 3.03 and 3.02 in./in. of percolated water.

                                   Table 56

                 Speed of Moisture Front, Milled Biotron Cell
                  Detection of    Travel Time      Distance   Speed
                Moisture Front  Between Levels     (inches)  (inches/week)
	(Days)	

Refuse Surface      2/4
Top probes          4/1               56             21      2.62
Middle probes       4/15              14             16      8.00
Bottom probes       5/17              32             14      3.06
                              266

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                                   Table  57

              Speed of Moisture Front, Unprocessed Biotron Cell



.Refuse surface
Top probes
Middle probes
Bottom probes
Bottom of bed
Detection of
Moisture Front

2/5
3/12
4/5
4/19
4/24
Travel Time
Between Levels
(Days)

36
24
14
5
Distance
(inches)


14
24
12
6
Speed
(inches/week)


2.72
5.84
6.00
8.40
      The unprocessed cell had been producing small amounts of
leachate five days after placement.  Up to the 77th day, the amount
totaled only 4.55 1.  Between the 77th and 80th day, production rose
to 11.78 1,  which indicated that the main moisture front had reached
the bottom. The occasional production prior to the 77th day from
installation indicates that some channeling occurred.

      A distinct difference between the movement of the water fronts
through the two cells was shown by the moisture curves.   The milled
refuse cell  showed a more rapid change in moisture from the initial
value to the saturated value for each probe.  The average time it
took the probes to indicate saturation had been reached was 13.3
days for the milled cell and 25.4 days for the unprocessed cell.
This indicates that the waterfront was more distinct in the milled
refuse.

      The milled cell produced leachate at a nearly constant rate
while production from the unprocessed cell was closely related to
rainfall.  This can be seen  from the curves  in Figure  91. In the
case of the  unprocessed cell,  approximately half of the total leachate
volume produced between two rainfalls was produced during the
first 24 hrs. after the rain. Direct channeling cannot be the main
reason for this.  If so, one  would expect a more dilute leachate shortly
after a rainfall than later in the period, but leachate analyses showed
only a slight difference.  The explanation must be that unprocessed
refuse is more permeable than milled refuse.

      The above results indicate that unprocessed refuse will reach
field capacity faster than milled under  similar environmental conditions,
                              267

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      The probable reason for this can be found in the difference
in evaporation rates, which is discussed below,  since  no significant
difference was found with respect to inches of penetration per inch
of percolating water.  The computed value of 3 in./in. percolating
water will not, of course, be generally applicable.

             Evaporation and Water Holding Capacity

      Since the volume of all water entering as rain or leaving as
leachate was recorded, it was possible to set up  a water balance
and compute the amount of evaporation. To eliminate the problem
of water storage within the refuse, the water balance was started
after field capacity had been reached.  May 16 was selected as the
starting date for the unprocessed cell because leachate production
and the moisture probes indicated that field capacity had been reached
at that time.  For the milled cell it was necessary to start from August
5, to avoid the effects of ponding and  drainage of surplus water.
The results are presented in Table 58.
                            Table  58

                 Calculation of Evaporation Rates
                      (Biotron Experiment)
Period
5/6 - 6/11
6/11 - 7/5
7/5 - 8/5
8/5 - 9/6
9/6 - 10/6
10/6 - 11/1
Days
36
24
31
32
30
26
Total
Rain
(liters)
271.2
364.0
208.2
196.3
154.4
131.7
Average
Rain
(liters /day'
7.53
15.18
6.72
6.14
5.15
5.06
Total
Leachate
(liters)



140.9
113.9
104.8
219.1
312.3
192.8
168.5
142.0
132.9
Average
Leachate
(liters/day)
M UP
6.08
13.02
6.21
4.40 5.26
3.79 4.73
4.03 5.10
Leachate
In Pet.
of rainfall
M


UP
Evapora-
tion
(in pet.)
M
80.8
85.9
, 92.5
71.7
73.8
79.6
85.8
92.0
101.1


28.3
26.2
20.4
UP
19.2
14.1
7.5
14.2
8.0
1.1
                               268

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      At the end of the experiment the moisture content  (dry weight
basis)  as determined on two samples from the milled cell was found
to be 136.3 and 101.5 percent.  The average moisture content was
118.9 percent.  The average value cannot be regarded as very accurate
because of the large difference between the two samples. By using
the initial and final moisture values , amount of rain, and volume
of leachate produced, the average evaporation of the milled cell
(over the entire test period) was calculated to be 30.3 percent.

      No final moisture test was run on the unprocessed refuse
because of difficulties in getting a representative sample; therefore,
the average evaporation of the unprocessed cell was calculated assuming
a final  moisture content of 121 percent as indicated by the moisture
probes.  Using the same method as used on the milled cell,  the average
evaporation was calculated to be 10.3 percent.

      In this study, both milled and unprocessed refuse were kept
uncovered.  Therefore, the difference in evaporation must be attributed
to the difference in physical properties of the refuse due to milling.
The large variation in evaporation rates found for the unprocessed
cell, as shown in  Table 58 ,  is  probably due to variations in total
moisture held within the refuse, rather than actual changes in  evapora-
tion rates.

      Comparison of evaporation rates given in Table 58 shows
that the milled cell had rates  2 to 3 times higher than the unprocessed
cell. This proved to be an important factor when considering the
total production of leachate and  pollutants.  There are probably
several factors affecting the difference, including:   (a)  milling results
in more effective surface area for evaporation, (b)  milled refuse
has more water-holding capacity, and (c) the finer void system
in the milled refuse may improve the upward transportation of moisture.

      Under field  conditions, evaporation rates will be highly  dependent
on the  local climate.  It is felt, however,  that the evaporation rates
found in this  study are low compared to what would be found under
most real climatic conditions. Reasons for this are the extremely
high humidity together with the frequent and "heavy"  rainfalls that
were used throughout this study.

      Although there was a rather large variation in the results
from the moisture probes (Figure 92) , it was possible to find average
values from the graphs of the moisture readings.  These average
values determined on a dry weight basis are presented in Table  59.
                              269

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                             Table  59

             Average Moisture Content  -  Biotron Cells
Unprocessed cell
Milled cell
Percent Moisture at Saturation
Top Probes
Side
108
123
Top Probes
Center
128
153
Middle Probes
Center
125
124
Bottom Probes
Center
125
136
«
Overall
Average
*
*.
121,0
134,0
      It was also possible to estimate the average moisture content
at the time when leachate production started.  For the unprocessed
cell, this calculation gave:
      Rain added up to April 24

      Evaporation:  0.10 x 550

      Water that entered the refuse

      Initial moisture content 16.1%
             550.0 liters

              55.0   1

             495.0   1

              79.5   1
      Total amount of water in the refuse    574.5  1
      Dry weight of
moisture content of
                       494
,was 494 kg, which gives an average
  = 116 percent. A similar calculation
for the milled cell gave an average moisture content of 138 percent.
The data thus indicate that milled refuse had a higher moisture content
at field capacity than unprocessed refuse.

                         Temperatures

      Moisture and temperature were recorded by the same probes
(Figure 93 ).  Of particular interest are the relatively constant
temperatures and the low peak values compared to results from other
studies done  at Madison and found in the literature.  Both cells
showed an initial peak at the level of the top probes. The low peak
temperatures , particularly at lower depths, suggest that the biological
activity was mainly anaerobic at these levels.  Data on peak temperatures
are given in Table 60.
                               270

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                            Table  60
                Peak Temperatures in the Refuse
                      (Biotron Experiment)
                      Peak Temperature
                               °F

Top Level
Middle Level
Bottom Level
Milled
101
102
95
Unprocessed
102.5
96.5
90.0
Milled
7
106
147
Unprocessed
7
63
154
Days Elcipsed
      There was a definite time relationship between temperature
and moisture. For the middle and bottom levels the rise in temperature
coincided with the increase in moisture as the wetting front reached
that level,  It is important to note that the temperature rise was
sharper for the middle level than for the bottom and also more marked
for the milled than for the unprocessed cell. This pattern reinforces
what was observed for the water movements described earlier in
this chapter. The coincidence between temperature rise and increased
moisture indicates a close relationship between bacterial activity
and moisture content.

      During the first 3 months, temperatures generally seemed
to decrease with depth.  After that time no such relationship could
be found. After  about 5 months a general decrease in temperature
was noted for both cells. The explanation for this temperature drop
could involve a decrease in biological activity because most of the
readily fermentable material had been removed.

                   Settlement  and  Degradation

      At termination of the experiment, settlement of the refuse
was determined by measuring the vertical movements of the four
corners of the steel frame lying on top of the refuse.  No settlement
was found for the unprocessed refuse.  In the milled cell the average
settlement was 0.66 in.  Hence, the  volume reduction was only 1.23
percent.

      Little evidence of degradation was found in the unprocessed
refuse. Printed paper was still easily readable and even orange
peel could be identified.  In the milled cell  considerable change
was noticed in the top 2 to 3 in.  This portion was dark brown in
color and had a mulch-like appearance. Deeper in the refuse bed
little  evidence of degradation could  be found.
                               272

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Evaluation of Leachate Data:

      In most instances the polluting potential of leachate is expressed
in terms of concentrations of various substances , as in mg/1. Usually,
numerous  graphs of concentration vs. time are plotted to give an
indication of the relative strength of the leachate produced.  Peak
values are also cited to show that leachate is stronger than most
municipal, and even some industrial waste waters.

      The above information can be and often is very misleading.
For instance, a COD  concentration of 50,000 mg/1 is of little concern
if only a negligible amount of leachate is produced.  Conversely,
leachate with a much smaller COD concentration can be very damaging
if produced in large volumes when compared to the dilution water
available.

      With these thoughts in mind,  graphs are shown indicating
the total amount of pollutants produced (grams) and the total volume
of leachate produced (liters) on a cumulative basis.  It is felt that
these graphs  will present  a much more meaningful indication of
the polluting  potential of the leachate produced by the milled and
unprocessed  cells.  Also included in this section are a few selected
plots of concentration vs.  time and total production vs. time.  These
plots will serve to illustrate that the use of peak concentration values
and of graphs portraying concentrations in general can be very
misleading and that tests in which the total pollutant production
can be computed are necessary for meaningful conclusions.

                       Grams vs.  Volume

      Graphs of the summation of the grams produced for each pollutant
vs . the summation of leachate volume are shown in Figures 94  through 98
The shapes of these graphs are very different from concentration
vs. time plots.

      Comparison of the milled and  unprocessed plots for each parameter
shows that the unprocessed cell produced about 1.4 times as much
leachate as the  milled cell did.  The difference is accounted for
in the fact that the milled cell had a higher field capacity and an
evaporation rate almost three times  as large as the unprocessed
cell.  Initially the leachate from the  milled cell was of average volume
but high in concentration of pollutants; therefore, production vs.
volume curves for this  cell are very steep during these first stages
of leachate production. In contrast, initial volumes of leachate produced
by the unprocessed cell were much  smaller,  as were concentrations;
thus unprocessed curves are not as steep as milled curves for the
same period.  In the  case of COD, alkalinity, organic nitrogen  and
NH3 nitrogen, the curves  eventually converge and  either cross
                              273

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278

-------
                 or run tangent to each other.  This indicates that milled refuse releases
                 more of the stated pollutants earlier in the degradation process than
                 does unprocessed refuse but also that the total production of these
                 contaminants by the two cells is similar.

                       The milled cell was found to produce more dissolved solids.
 *               This may be explained by the fact that milling exposes more surface
                 area from which solids can be more quickly dissolved during leaching.
                 The same reasoning may explain the difference in production of
 ,               total hardness.  The largest difference in total production was found
                 for iron, where the milled cell produced more than five times as
                 much as the unprocessed during the 270-day study.  One reason
                 for this could be that milling removed some of the protection originally
                 present on iron surfaces, such as paint or other coatings.

                       The apparent difference in amount of chlorides cannot be
                 used as the basis for a definite conclusion because the results for
                 the milled cell are unreliable due to severe problems with interferences
                 in the test.  For total and ortho-phosphate, the milled cell showed
                 a higher production and the curves were  diverging at the end of
                 the study, indicating that the difference in total production probably
                 would have increased if the test had continued beyond the 270 days.
                 For NHn -N, the production was nearly five times larger for the
                 unprocessed than  for the milled cell.  For organic N, the unprocessed
                 cell showed higher production,  but the difference is too small to
                 be significant.

                       The production of nitrogen and phosphous is believed to be
                 partly dependent on bacterial activity.  Some of the ammonia nitrogen
                 found in the leachate is probably produced by bacteria , but from
                 the large difference in total NHo -N alone, it cannot  be concluded
                 that there was a much higher level of bacterial activity in the unprocessed
                 cell. No other parameters give  support to a conclusion of that sort.

                       Examination of the total amounts of  the various substances
                 shows clearly that the amounts carried away by the leachate are
                 very small, or almost negligible compared with the total  amounts
                 originally present in the refuse. The total amount of solids removed
                 by leachate, for instance, was 7.495 kg (16.8 Ibs.)  for the milled
                 cell, while  the total dry weight of refuse was 1038 Ibs. This represents
 >                a weight reduction of 1.62 percent.  The total amount of iron in
                 the leachate from the milled cell was found to be 0.320 kg (0.718
                 Ibs.) , while the initial amount in the refuse was 83,9 Ibs.  This
                 represents  a reduction of about  0.85 percent from the initial weight
 *                of cans and metal.  There is reason to believe, therefore, that production
*                of most of the substances would have continued for a relatively long
                 time if the test had not been terminated.  It should be kept in mind
                 that this experiment was run under conditions that promoted rapid
                                               279

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degradation, and hence rapid production of pollutants.  Under most
landfill conditions, pollutants will normally be released at a much
slower rate.

               Grams and  Concentrations vs. Time

      As stated previously, an attempt will be made in this section
to illustrate how misleading contaminant concentration data alone
can be when describing the total effect of leachate production.

      Figures  99 and 100show for comparison, curves of concentration
and total production vs. time both for  COD (a measure of the concentra-
tion of organic matter)  and TDS (a measure of the inorganic concentra-
tion) .  Examining the concentration curves, it is evident that the
milled eel] has peaks ranging from 2 to 3 times as high as the unprocessed.
These concentrations remain very high over some 20 percent of
the leachate production time for the milled cell. By  observation,
it would seem that leachate from the milled cell had much  more polluting
potential than that from the unprocessed cell.

      In contrast, examine total production vs. time. By observing
the end points,  one can see that in the case of COD the unprocessed
cell actually produced more pollutant even though the milled cell
had a peak concentration 2.5 times that of the unprocessed cell.
In the case of TDS, the milled cell produced only slightly more of
the pollutant even though the peak concentration was almost 3 times
as great.

      In all cases the unprocessed cell produced pollutants first,
approximately 40 days before the milled cell.  The rate of total production
by the unprocessed cell is at first fairly low and  then increases
sharply after a  few days .  Note that the slope of the total production
curve at any point indicates the rate of production of that particular
pollutant, where rate is defined as grams/day. Note also, the initial
production of small amounts of contaminants by the unprocessed
cell, which  are negligible in the cumulative curves.

      Production in the milled cell of both COD and TDS was initially
very sharp  and dramatic. Once production reached approximately
that of the unprocessed cell, the curve tapered off and followed
nearly the same slope as  the unprocessed cell. Note that the sudden
increase in slope at approximately 170 days for the milled cell was
due to the ponding effect. Ponding is  also thought to be responsible
for the fact that the latter end of the COD concentration curves in
particular did not cross, as had been  observed in previous experiments
comparing milled and unprocessed refuse.
                              280

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                                         281

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  282

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                      pH and Conductivity

      The pH for both cells , as shown in Figure 100,  remained
constant or was slowly decreasing throughout the study, except
for some early unprocessed leachate samples where values between
6 and 7 were noted. Both cells had a pH of 5.10 to 5.30 at the time
the highest production of COD occurred, decreasing to 4.60 to 4.80
toward the end of the experiment. In past work, a close relationship
between iron concentration and pH in leachate has been reported.
Undoubtedly, these parameters are closely related chemically, but
this study tends  to show that other factors might be more important
for the release of iron from the refuse.  The two cells  exhibited
nearly identical pH curves, but the iron production was much higher
in the milled than in the unprocessed cell.

      Tests for conductivity were also performed on leachate samples
from each cell. It has been determined that conductivity is usually
a good estimate of the TDS content of leachate and is often run on
leachate samples in lieu of tests for TDS since it is easier and faster
to complete. The conductivity and TDS curves obtained for each
cell were very similar in shape; thus, the conductivity curves are
not presented here. The maximum value obtained from leachate
collected from  the unprocessed cell was 12,500 u mho/cm, 91 days
into the test.  The  conductivity gradually decreased to a value near
2,650 u mho/cm at the end of the study. The milled cell had a
peak value of 19,000   u mho/cm, 120 days into the test. From this
peak the figure dropped very rapidly to near 2,500 n mho/cm and
remained relatively constant throughout the remainder of the test.

Gas Data:

      The exhaust air from the rooms was analyzed for CC<2 and
total hydrocarbons as  CH/p  CO2 is produced by both  aerobic and
anaerobic microorganisms.  CH4 is produced only under anaerobic
conditions. Aerobic bacteria were probably less important in the
degradation process than anaerobic, as indicated by the relatively
low peak temperatures measured in the refuse.

      Air flow was held constant at one cu.  ft. /hr.  With a room
volume of about 225 cu.ft., this gives an average detention time
of 225 hours , or  more  than 9 days .  Because of the long detention
time  and daily  fluctuations in inlet air composition,  it  was natural
to use average concentrations of CO2 and hydrocarbons in the supply
air.  For CO2 the average over the entire experiment was found
to be 343 ppm. For hydrocarbons it was found most correct to compute
one average for the first 80 days and another for the rest of the
test period, because the first 80 days showed considerably higher
concentration of CH4 in the supply air than recorded later. The
first average was 5.41 ppm based on 15 observations, varying from
3.90 to 6.45 ppm.  The second average was  2.78 ppm based on 77
observations varying from 1.05 to 6.02 ppm.
                              283

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      Figures 101 and 102 show concentrations of CC>2 and CH4 vs.
time.  From the curves for CO2 concentration, both cells showed
peaks a few days after the start of the experiment. The milled cell
peaked at 530 ppm after 2 days , while the unprocessed peaked at
550 ppm after 5 days.  After the peak the milled cell had a rather
rapid drop, reaching concentrations close to that of the average
supply air after 50 days.  After that time the concentrations stayed
equal to or slightly above that of the average supply  air.   The unprocessed
cell had a slower drop, where COo concentrations stayed 50 to 100
ppm above the average up to 180 days into the study. After that
no significant difference could be found between the  two cells.

      The recorded concentrations seem to indicate a very low CO2
production; however, CC>2 gas is soluble in water and a large portion
of it could be transported out by the leachate.  The concentration
of CO 2 in water can be calculated from pH and alkalinity data  by
use of the equation:

            (H+)  x (HCO3-)
                           = K = 4.45 x 10~7,
                 (C02)

neglecting activity corrections.  Knowing the concentration of CC>2
and leachate production, the amount of dissolved COo becomes 2.8
cu. ft./day of CO2 gas .  The highest concentration of CO2 in the
exhaust air recorded by the CO2 analyzer was about 250 ppm  above
the supply air concentration.  An air flow of one cu. ft./hr. gives
24 cu. ft./day and with a concentration of 250 ppm by volume this
equals:

            24 x 250 x 10~6 = 0.006 cu. ft./day of CO9.
                                                 £»

      This  calculation shows  clearly that the amount of CO2 escaping
as gas was negligible compared with the amount carried by the leachate.
The data obtained from the CO2  analysis , therefore,  cannot be used
to calculate the total production  of CO2.  It is also very unlikely
that the shape of the CO2 curve  reflects the relative changes in production,
The peak production of CO2 probably occurred near the peak  for
the leachate parameters rather than immediately after the start of
the experiment.

      The hydrocarbons measured in this test are believed to be
mainly methane (CHJ .  This  gas has very low solubility in water,
consequently the gas data should give good information about the
total gas production. From Figure  102, it can be seen that for
the first 80 days the production  of CH4 was negligible. Between
80 and 170 days there was evidence  of some CH4 production.  Exhaust
air concentrations were 2 to 2.5 pprn above the supply air average
of 2.78 ppm during this period.  After 176 days an apparent rapid
increase in methane production  occurred in both cells .  During
                             284

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               286

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the rest of the experiment,  methane concentrations remained relatively
high with an average of about 23 ppm for both cells.  As can be
seen from the graphs, the daily variations were rather large, and
no significant difference could be found between the two cells.
The main reason for the variation is felt to be the technique of sampling
and analysis.

      By calculation, the total volume of methane escaping from
each cell during the 270 days' tests was 0.052 cu. ft.  In light of
this, it can be concluded that methane production during the experiment
was almost negligible. One of the main reasons for the low methane
production is felt to be the  unusually low pH when compared with
other degradation studies.  This provides a very unsuitable environment
for the methane-producing  bacteria, which prefer a pH value near
neutrality.  It should be noted that methane production was  increasing
toward the end of the study and that the pH would probably have
approached neutrality had the experiment continued.  (See the ponding
study at the end of this section for additional discussion on this
matter.)

Closing Comment:

      Direct use of data from this experiment has certain limitations.
It must be kept in mind that the test was carried out under artificial
environmental conditions and with refuse of a specific composition.
In applying the data to actual landfill conditions, the effects of climatic
variations, the use of cover,  and different refuse composition must
be considered.  Also, it should be remembered that this experiment
was designed to compare the early stages of decomposition,  those
stages thought to be of most concern from previous studies on milled
refuse, so it lasted only 270 days. Reliable conclusions concerning
total production of pollutants  over a long period must be based on
long-term evaluations.

PONDING STUDY

Description of Ponding in the Milled Refuse Cell:

      Both containers used in the Biotron were designed to have
free drainage of leachate; but for the milled cell this proved not
to be the case.  While the unprocessed  cell started to produce leachate
regularly after 10 weeks, the milled cell produced only very small
quantities after 23 weeks .  A  clogging of the drain was suspected,
and on July 21, the room with the milled refuse container was opened.
The plastic hose connecting the container with the drainpipe was
indeed clogged.  This hose was replaced and the ponded leachate
drained out. The cell was  allowed to drain until July 28 without
adding rain. In addition, the container did not prove to be  completely
watertight and some leachate  leaked out. Since the room had no
drain, the spilled leachate, minus evaporation,  remained on the
floor.  This leachate was collected and  the volume determined.

                              287

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      The incident made it more difficult to provide direct comparisons
between the two cells as originally desired.  It was important, therefore,
to back calculate or reconstruct some of the data lost because of
ponding.  Essential in this respect was:  (a) calculation of total
volume of leachate that had leaked out of the container; (b) estimation
of the starting date for leachate production had the drain been open;
(c)  estimation of leachate composition had the drain been open;
and (d) determination of the effects of ponding on the decomposition
process both during and after the actual ponding period.

      Existing data could be  used for the first three points.  To
solve the fourth question, a small scale degradation study was set
up.  This study will be discussed in detail later  in this section.

       (a) Obviously some evaporation had taken place while the
leachate covered the floor. The following data was used to calculate
the  evaporation loss:  total volume of leachate collected from the
floor, the results from the analysis of this laachate,  and the results
from the analysis of three samples obtained through the clogged
drain before July 21. The calculation also had to be based on two
basic assumptions. First,  the change in the values  tor conductivity,
TDS, Ca-hardness, chlorides, and iron, was due to a more concentrated
leachate because of evaporation.  Second, the average values computed
from the analyses of the three eariy samples ware close to  the correct
initial  values for the spilled leachate.  The fact that pH for the spilled
leachate was close to the values found in the three early samples
adds validity to the assumptions.

      With the two stated assumptions  in mind the average concentration
factor due to evaporation was calculated to be 2.51.  Knowing the
volume of leachate collected from the ficor to be 53 liters, an estimate
of the total spillage is 2,51 x  53 - 133 liters,

       (b) Back calculation of the starting date for leachate production
was based on the volume of leachate drained from the cell after the
drainpipe was repaired plus the estimated volume of spillage. Also
used were the average evaporation ratu and. the volume of  rain supplied.
The estimated date of the starting date of leacbate production corresponding
to rainfall was  May 28.

      An estimate of the same starting date could be obtained from
the  moisture probe data.  As  described previously, the moisture
front reached the bottom level probes on May 17. These probes
were located three inches above the bottom of the refuse bed.  The
moisture front moved downward with an average speed of  3.5 in./wk.
The moisture front could, therefore, be expected to reach  the bottom
on May 23 or 24.
                               288

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      (c) The analyses of the three small leachate samples obtained
while the drain was clogged were used to estimate the results that
would have been obtained had the cell been free draining and started
leachate production on May 28.  The time sequence for the early
leachate data had to be changed so that results from the period between
July 1 and July 23  were used for the period between May 28 and
July 2.  The total amount of leachate produced up to July 23 was
then portioned out  according to the new time scale. It cannot be
claimed that the results for the period between May 28 and July
2 give a correct picture of what would have happened without the
clogging, but the results are valid as  average values for the leachate
produced during this period.

      (d) From visual evidence outside the container it was estimated
that the leachate had built up 34 in. above the bottom of the refuse,
where the top 24 in. of refuse remained above the water at maximum
ponding. This ponding probably had an influence on the biological
activity in the cell, thereby affecting the release of pollutants , gas
production,  etc. There was also a possibility that this ponding
could affect the behavior  of the cell even after it had been drained.
This problem was examined in a special study.

Small-scale Experiments  to Study Effects of Ponding on Refuse Decomposition:

      The equipment used for this study consisted of two plastic
bottles from which the bottoms had been  removed. The total volume
of each was 16 1. The bottles were placed upside down and  equipped
with a drainpipe from the bottleneck and a plastic screen near the
bottom.

      The containers were filled by hand with milled refuse from
the Olin Avenue milling plant.  For each container the volume of
refuse was  14.8 1 and the total  refuse weight was 4.30 kg.  This
gave an in-place density  of 489 Ibs./cu,  yd.  The initial moisture
content was  determined to be 44.5 percent based on dry weight.

      The containers were placed in an incubator which was set
at a temperature of 32° C. The refuse surface was covered with
a plastic sheet to minimize evaporation.  One container was filled
with 10 1 distilled water and the drainpipe was kept closed.   The
other container had free drainage throughout the experiment, and
no initial water was added. Both containers were supplied with
500  ml distilled water twice a week. The water was distributed
evenly over the surface by use of a can with a perforated bottom.
In order to  keep the water level constant in the ponded cell, leachate
was taken out in amounts equal to the amount of water added.

      Since the experiment was started on August 12, the refuse
composition was different from that used in the Biotron experiment.
                              289

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In particular there would be more greens in this sample.  This fact,
and the difference in density and environment, exclude any direct
comparison of the results from this pilot study with those obtained
from the Biotron experiment.  However, it was the relative behavior
of the two cells that was of main interest.

      The pilot study was run with one ponded and one drained
container from August 12 to September 27, or 46 days.  After September
27, both cells were run with free drainage.  The test was  terminated
after 88 days.  The total amount of distilled water supplied was
21,500 ml for the ponded cell and 12,000 ml for the drained.  The
total amount of leachate collected from the ponded emd drained cell
was 15,640 ml and 7,399 ml, respectively.

      A less extensive program of analysis was performed in this
experiment than in the main study. The emphasis was put on the
leachate analysis where only the most important and most  characteristic
parameters were selected.  The following tests were run on the
leachate:  pH, conductivity, COD,  total hardness, Ca-hardness,
chlorides , and solids .  In addition, the volume of leachate was measured,
The same procedures were used as in the main experiment, except
that settling time before decanting was reduced from 4 hrs.  to 1
hr. In addition to the leachate analysis , the temperature in the
room and within the refuse  (as measured by a glass thermometer
imbedded in the refuse)  was recorded.

Results From the Study:

      Cumulative amounts of pollutants produced vs.  leachate volume
are shown in Figures  IQSand 1Q4-  Except for chlorides, the two
cells produced nearly equal amounts of pollutants for  equal amounts
of leachate until the ponded cell was drained.  At this point the
two curves diverge, with the ponded cell producing at a relatively
constant rate and the drained cell at a decreasing rate. This is
hard to explain, but it is safe to assume the difference is due to
the ponding effect.  Lower pH in the ponded cell could be  one reason
why pollutants were more readily released from that refuse; but
whether the difference in pH for the two cells was due to the ponding
or other factors  cannot be fully evaluated from this experiment.

      Graphs of the tested parameters with respect to concentration
are shown in Figures  105 , 106 . and  107.  These curves also illustrate
the ponding effect quite  remarkably.  The drained cell curves exhibit
a shape comparable to other curves obtained during previous degrada-
tion studies.  Peak values are seen relatively soon in the test followed
by a pronounced and then more gradual decline in concentrations.
The ponded cell exhibits no such change but seems to have  a curve
maintaining almost constant and relatively high concentrations.
The slight decline that did occur in concentrations happened after
the cell was drained.
                              290

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«Mto
i,:
          I   '    I   '    I   '    I
          —0	  TOTAL HARDNESS, PONDED
          —O	   .    .  f DRAINED
          —Q	  CHLORIDES   , PONDED
          —Q	     •      , DRAINED
                       6      8      10      12
                        LEACHATE  VOLUME (LITERS)
14
     Figure 103.   Cumulative Hardness and Chlorides vs.  Volume
                                     I   r
                 COD. PONDED
                  " .DRAINED
                 TDS.PONDED
                  • .DRAMED
                       6      8     10     12
                        LEACHATE  VOLUME  (LITERS)
      Figure 104.   Cumulative COD and TDS  vs.  Volume

                                    291

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     D15860
 14
                        I   '    I    '   I    n

                         •CONDUCTIVITY, PONDED
                             "      , DRAINED
                         •TDS        . PONDED
                           •         . DRAINED
                                                        1    '   I
                        3       4       S       6
                     .LEACHATE  VOLUME (LITERS)
        Figure  105.   Conductivity and TDS vs. Volume
                                                                         10
 24
 20
r6
§
  -.—i—i—i—
  —0	 COD, PONDED
  .--o	  . f DRAINED
  —O— pH . PONDED
- ~ -O—  " • DRAINED
                              	o-
                                               ' ~D	
                                                       -D
       I       23496
                         LEACHATE   VOLUME (LITERS)

    Figure 106.   pH  and  COD vs. Volume
                                                                           10
                                         292

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                     293

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      The difference in pH for the two cells is striking.  The ponded
cell had a pH of 5.20 at the start, but this declined through the experiment
to 4.80.  pH for the drained cell also started at 5.20, and stayed
about constant for 4 weeks.  Then, there was a rapid rise in pH
value during the next 2 weeks from  5.27 to 7.00.  This change coincided
with the second rapid drop for the other parameters.  The simultaneous
change in pH and COD may indicate  a change in the type of bacteria
from producers of organic acids to methane producing bacteria.
pH for this  cell remained slightly above neutral during the rest
of the study.

      It is clear from this study that ponding in the milled cell in
the  Biotron changed the results, somewhat, from what they would
have been.   Furthermore, this study shows that the total amount
of pollutants produced over a longer period will be increased by
ponding. Consequently, the calculated total amounts for the milled
cell in the Biotron are probably larger than what would have been
found in a situation with free drainage.  Also, the study showed
that ponding tends to depress peak concentrations, but in contrast,
concentrations will  remain relatively high for a longer period of
time than in a comparable drained situation.  Finally, the gradual
increase in pH of the drained cell to a value of 7.0 suggests that
ponding reduced the rate of methane production in the milled Biotron
cell.
                               294

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      VII. TREE GUOvJ'JJl AND OTHER VEGETATION ON REFUSE

                             TREES

INTRODUCTION

     A study was initiated to determine the ability of milled refuse
to support tree and shrub growth.  It was performed in conjunction
with the Olin Avenue refuse milling and landfill operations of the
City of Madison.

     The amount of published information on this subject is minimal.
Several instances of problems in plant growth on landfills were described
in a report in "The American City" (1965).  It cited a problem caused
by gas which killed several trees on a five-year-old site in Elmhurst,
Illinois.  At a golf course constructed on a newly completed landfill
in Savannah, Georgia, only six pine trees survived out of 200.  It:
was found that only those trees with a thick blanket of soil between
the roots and the refuse had remained alive.  It was also found that.
there were differences in tolerance to landfill conditions among several
varieties of Bermuda grass.  D.K. Holland, Director of Public Works in
Kenosha, Wisconsin, wrote of substantial difficulty encountered in
growing trees, shrubs, and grass in parks established on sanitary
landfills (personal communication).  lie attributed the problem either
to gases being expelled from the refuse or to lack of an adequate soil
base over the fill.  Such instances point to the need for research on
what causes such problems and what can be done to alleviate them.

OBJECTIVES

     This project was designed to determine the soil properties and
species which could be used to achieve successful establishment and
growth of trees and shrubs.  The type, and thickness of soil material
covering the refuse as well as tree and shrub species were varied to
determine v-hich combinations gave the best growth.  Ten species of
seedlings were grown to see if any had an advantage under landfill
conditions.   Experimental plots were established on both milled and
unprocessed refuse to determine if there were any differences in growth
due to the composition of the underlying refuse.  Additional plots were
established to determLne the effects of fertilizer on the growth of trees
on the landfill.

     The method of application of the soil cap produced some modifi-
cation of the original objectives.  The soil cover is often compacted
to slow decomposition of the underlying refuse and to reduce infiltration.
In this car.e, however, the extensive grading necessary to obtain desired
soil depths so compacted the. soil that the roots did not achieve appre-
ciable penetration and have therefore not yet (September 1972) entered
the refuse as originally planned.  As a result, the full effect of the
underlying refuse on tree growth has not been completely determined.
Although gas evolving from the refuse diffuses through the soil, the
composition of the soil air differs from that in the refuse.  Had the
roots entered the refuse, they would have encountered an environment
which ILkely would have been very poor for plant growth.

                               295

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EXPERIMENTAL DESIGN

     The study consisted of two major blocks; one on unprocessed refuse
and one on milled refuse.  The blocks were laid out and surveyed to
set up the depths of soil cover desired.  Since milled refuse does
not require a soil cap, the cover material was applied solely to improve
the conditions for tree growth.  rihe additional cover on the unprocessed
site was also applied to determine the effects of depth of soil cover
on tree growth.  The soil material was trucked in and spread to the
prescribed grade with a bulldozer.  In the application and grading of
the fill to its prescribed depths, the soil cap was compacted greatly.

     The soil material and the soil thickness were varied on the two
blocks as follows:  Each block was divided into 6 x 30 meter plots.
The plots were separated by 3-meter buffer strips which were planted
to grass.  Three of the plots in each block were covered entirely with
subsoil--one to a depth of 15 cm., one to 30 cm., and the other to
45 cm.  The other three plots in each block had the three depths of
subsoil plus a 15 cm layer of topsoil applied above the subsoil.  The
fertility plots had only 15 cm. of subsoil applied to the milled refuse.

     During application of the soil materials, actual thicknesses
achieved varied significantly from the prescribed thicknesses.  Because
of this, the depths which are referred to in the experiment are only
approximate.

     Ten species of plants were planted in the experiment:

           White ash                Fraxinus americana
           Ninebark                 Physocarpus maxim
           Gray dogwood             Cornus racemesa
           Silky dogwood            Cornus obliqua
           Wayfaring tree           Viburnum lantana
           Buffaloberry             Shepherdia argentea
           Russian olive            Elaeagnus augustifolia
           Red pine                 Pinus resinosa
           Jack pine                Pinus banksiana
           Crab                     Malus spp.

For simplicity, all plants will be referred to as trees in the following
discussion.

     Ten trees of each species were planted in each plot.  Trees were
planted four feet apart in rows of five of one species.  Rows were
placed five feet apart.  Each row of five trees was randomly located
within each half of the plot.  The block on the milled refuse was planted
on May 25, 1970; that on the unprocessed refuse was planted June 10, 1970.

     A supplemental experiment consisted of 50 each of jack pine, red
pine, and white ash trees in separate plots on the milled refuse to
evaluate effects of fertilizer on tree establishment and growth.  The
trees were spaced as above in plots 6 x 15 meters.  Fertilization was
                                296

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done using one ounce polyethylene packets in varying quantities.  The
four randomized treatments were: 1) check (no fertilizer), 2) four
packets, 3) loose fertilizer from two packets, and 4) loose fertilizer
from two packets plus four intact packets.  The fertilizer was applied
15 cm deep in the soil in a 15 cm radius circle around each tree two
weeks after planting.

     Additional trees, which were not originally planted, were healed
in and were used to replace the dead trees on all of the plots on
July 21, 1970.  During the first summer (1970), the plots were watered
four times for a total of less than half a hectare cm.  There was
no further irrigation after the first summer.  During the first two
summers of growth, weeds were controlled by mowing.  Weeds near trees
were also controlled to some extent through the use of Amitrol-T,
applied at a rate of 3 liters per hectare.  It also became necessary
to spray the trees with a repellent to protect them from rabbit damage
in the winter of 1970-71.  A recording rain gauge was installed at
the landfill and records of precipitation were kept from August 1970
through November 1971.

Plant Evaluation:

     The trees were periodically checked to determine mortality, vigor,
and growth.  Records of the trees' condition were kept along with
periodic height and diameter measurements.  Because of the bushy type
of growth of many of the trees (crab, ninebark, Russian olive, buffalo-
berry), height and diameter were difficult to determine.  This made it
necessary to mark the leading shoots so that the same ones could be
measured each time.  Marks were also made on the shoots approximately
7 cm. from the soil surface so that diameter measurements could be
taken at the same point each time.

     A total of 43 samples for foliar analysis were taken; the samples
represented three species (jack pine, red pine, and white ash) and
included milled and reprocessed blocks, several fertility plots, and
reference sites.

     The white ash tissue samples were analyzed for N, P, K, Ca, Mg,
Al, Ba, Fe, Sr, B, Cu, Zn, Mn, and Cr.  Jack pine and red pine samples
were analyzed for N, P, Ca, and Mg.  All tissue analyses were performed
by the Wisconsin State Soil and Plant Analysis Laboratory.

Soil Evaluation:

                        Physical Analyses

     Tensionmeter measurements to determine soil water potentials were
taken on the milled site from July through October, 1971.  Eight tensio-
meters were placed in four areas on the milled site at depths of 12.5,
27.5, and 42.5 cm.  Measurements were taken at intervals of two to
three days throughout the period.  Soil bulk density was determined at
several locations on both the milled and unprocessed sites using an
excavation method.  Soil texture was determined on several samples
                                297

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taken at various locations on both the milled and unmilled sites using
the Bouyoucos hydrometer method.

     Determination of hydraulic conductivity was made on soil cores
obtained with a Uhland sampler.

     For determination of moisture retention curves encompassing high
as well as low values, samples with field structure were used.  Bulk
densities were determined using these volumes and the dry weights of
the uncoated clods.  Particle density of the clods was determined
using a glass pycnometer.  Porosity was calculated using bulk density
and particle density.

     Gas samples were taken from the soil four times from May to
August, 1972.  Ten 5-cm.-wide pipes with four small holes near the end
were driven into the soil after a smaller soil core had been removed
to aid in the driving.  They were placed in four areas on the milled
site at depths of 15 cm. and 30 cm., and at 7 cm., above the refuse
surface.  The pipes were capped tightly on top with rubber stoppers
fitted with Tygon tubing.  Gas samples were taken by the following
procedure:  The tubing leading from the pipes was attached to a vacuum
pump which pulled the soil atmosphere through a glass cylinder equipped
with a stopcock at both ends.  The cylinder was first emptied of air
by pumping while only the stopcock nearest the pump was open.  The
other stopcock was then opened and soil gas drawn through the cylinder
for 15 seconds at 0.35 kg./cm.2 suction.  The stopcock nearest the pump
was then closed and the gas in the cylinder allowed to reach equili-
brium with the gas in the pipe for an additional 15 seconds.  The stop-
cock leading to the soil pipe was then shut and the gas in the cylinder
retained for analysis.  The samples were analyzed for carbon dioxide,
oxygen, nitrogen, and methane on a gas chromatograph.

     To determine the degree of soil compaction and ease of root pene-
tration, measurements were taken with a pocket penetrometer.  Readings
were taken at several depths in two separate profiles in the landfill,
and under pine and birch stands in the University of Wisconsin Arboretum
for comparison with landfill values.  In total, two landfill profiles
and two Arboretum profiles were sampled at three different depths which
varied with the profile.  Nine determinations were made at each depth.

     Soil temperatures were recorded at intervals from January to June
1972 using diodes.  Fourteen diodes were placed in seven areas on the
milled site at depths of 7, 15, 30, and 41 cm.; the 41 cm. depth diode
was 2 cm. above the refuse surface.

                       Chemical Analyses

     Composite soil samples were taken for chemical analysis in July
1970.  Samples were analyzed for total N, available P and K, exchange-
able Ca and Mg, organic matter content, and pH by standard methods.
                                298

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                 RESULTS AND DISCUSSION

                 Plant Evaluation:

                                            Tree Growth

                      Growth measurements were taken on all ten species planted, but
                 only white ash, jack pine, red pine, and buffaloberry were selected
*                for representative analyses of growth (Tables 61 and62 ).  Although
                 one year (November 1970 to September 1971) is a rather short period
                 upon which to base conclusions (it often takes longer to increase a
                 tree's photosynthetic capability), some differences in growth were
^                found in this time.  On spoil sites, it has often been found that few
                 growth differences occur after two years in spite of highly variable
                 site conditions.  In this study,  however, soil type was found to be
                 a significant factor in producing growth differences in a single year.
                 Most of the species other than jack pine increased in height and
                 diameter more on topsoil than subsoil.  This is reasonable because the
                 low fertility of the subsoil was  likely adequate for the low-demanding
                 jack pine.   White ash and buffaloberry had much greater growth than
                 red and jack pine.  This is to be  expected since white ash is normally
                 quickly established, while the pines, expecially red pine, are slowly
                 established.  White ash is also much better adapted to dense soils than
                 red and jack pines.  It was noted that the condition of the planting
                 stock used in this study had little influence on the growth achieved.
                 For example, the buffaloberry stock which had been stored for two
                 weeks prior to planting produced  greater growth than seedlings which
                 were planted in "optimum" condition.

                                           Tree Survival


                      Many of the planted trees (19 percent) died the first year of the
                 study (Table 63).  The losses were attributed to establishment shock,
                 poor planting stock, and poor planting conditions.  The unprocessed
                 block was planted two weeks later than the milled block,  when the
                 soil was very dry.  Such dry conditions are very poor for tree establish-
                 ment.  The delay in planting also caused a great deterioration of the
                 planting stock.  These two factors, then, contributed to the much
                 greater initial mortality on the  unprocessed site as compared to the
                 milled site.

«                      Much greater initial mortality occurred on the unprocessed topsoil
                 block than on the unprocessed subsoil block; this difference can be
                 partially explained by the greater weed competition on topsoil than
                 subsoil.  The greater week growth on topsoil on both blocks was due
                 to a greater carry over of weed seeds in the topsoil than in the subsoil.
*                This is one problem which must be dealt with if topsoil is used for
*                 tree planting.
                                                 299

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                                 TABLE 61
                 Percent Growth Increase* Of Various Plots
Plot**
Milled (A)
(3)
(C)
(D)
(E)
(F)
Unprocessed (&)
(B)
(C)
(D)
(E)
(F)
White Ash
Ht.
—
43. 0
23. 5
53.7
/I O "
50. 5
27. 6
61. 7
93. 8
71. 1
41.7
19. 7
Diam.
--
51. 3
28.4
61. 5
*7. 6
70. 4
15. 1
33. 2
54. 9
69. 2
71. 4
24. 6
-
Red Pine
Ht.
2. 8
2. 3
1.6
11. 1
14. 8
18. 9
9. 9
10. 1
11. 2
13. 0
--
—
Diam.
8. 0
3. 5
10. 6
19.6
13. C
20. 6
5. 5
13. 0
8. 8
27. 2
38. 0
9. 0
Jack Pine
Ht.
29. 3
41. 6
12. 8
--
19. 0
25. 8
6. 6
11. 1
12. 9
29. 1
24. 6
17. 3
Diam.
19.7
34. 2
9.4
--
4.7
17. 8
7.6
18. 8
14.6
10. 6
16. 7
15. 1
Buff
Diam.
32. 6
27. 5
6. 7
30. 2
vJ«J. ^
35.6
57. 6
55.6
67. 8
39. 2
87. 7
12. 3
  From November 1970 to September 1971.
**
  Plot A  -  15 cm subsoil
      B  -  30 cm subsoil
      C  -  45 cm subsoil
      D  -  45 cm subsoil beneath 15 cm fopsoil
      E  -  30 cm subsoil beneath 15 cm topsoil
      F  -  15 cm subsoil beneath 15 cm topsoil
                                    300

-------
                                      TABLE 62

                Percent Growth Increase* On Basis Of Various Factors


_. . Milled (M)
Block
Unprocessed (U)
Soil Type Subsoil (S)
Top soil (T)
Milled, Subsoil
Unprocessed, Subsoi!
.X
Soil Type Milled, Top soil
Unprocessed, Topsoi!
_ ... 15 cm
Depth
of 30 cm
Soil . _
45 cm
1
**
Subunit
2
V/hite Ash
Ht.
. 45
55
50
48
33
62
51
45
49
49
50
50


49
Diam.
52
45
38
57
40
37
60
54
49
51
45
52


45
Red Pine
Ht.
9
11
7
14
2
10
15
13
9
10
12
11
*

9
Diam.
15
14
9
21
8
9
20
24
15
14
14
16


13
Jack Pine
Ht.
29
17
19
23
31
10
23
23
21
25
16
20


22
Diam.
21
14
18
14
24
14
12
14
12
21
14
14


18
B. Berry
Diam.
31
57
47
39
27
60
33
52
39
49
41
42


44
**
From November 1970 to September 1971.

Subunit  1   -  east half of plot
         2   -  west half of plot
                                         301

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                       TABLE 63
 Percent Tree  Survival On Basis Of Various Factors

Milled
Unprocessed
Subsoil
Topsoil
Plot * A
B
C
D
E
F
Milled, Subsoil
Milled, Topsoil
Unprocessed
Subsoil
Unprocessed
Topsoil
Total
November
1970
92
71
89
74
87
89
90
82
70
68
93
92
86
56
81
July
1971
77
77
74
70
76
72
74
80
33
62
66
87
82
52
72
July
1972
25
45
36
34
29
42
37
43
28
30
17
34
55
45
45
*From November 1970 to September 1971.
                          302

-------
     Severe desiccation of many of the trees was noted during the
first year.  The dry conditions the first year made it necessary to
irrigate both blocks to prevent much greater mortality.  Although only
1/2 cm. hectare (1/2 acre-inch) of water was applied in total, some
irrigation was necessary.  Because of the very poor initial survival,
many of the trees were replaced approximately a month after the original
planting dates.  The survival data do not take into account the fact
that many trees were replanted.

     Studies of plant growth on spoil banks have indicated that most
tree mortality occurs the first year after planting, with very small
increases in mortality occurring in later years.  The results of this
study disagree with this trend.  Little additional mortality did occur
on either site until the fall and winter of 1971-72 when a rapid upsurge
in mortality (65 percent in total) occurred; this was attributed to a
lack of adequate soil aeration, as will be discussed later.  One of the
reasons for such a hypothesis is that all species survived better as
of 1972 on topsoil on the milled site while all species did better on
subsoil on the unprocessed site.  A likely reason for the much better
survival on topsoil on the milled site is that the topsoil had an
additional 15 cm. of soil cover as compared to the subsoil.  This
extra soil acted as a buffer between the tree roots and the gases
produced by the decomposing refuse.  Since the trees also had better
survival on the unprocessed than the milled site, it was also hypo-
thesized that gas production by milled refuse was greater than for
unprocessed refuse.  All species except jack pine had better overall
survival on the unprocessed than on the milled site; poor initial survival
of jack pine on the unprocessed site accounts for this discrepancy
(Table 64).  In addition, white ash and crab had very much better
total survival than the other species as of 1972.

                     Root System Evaluation

     Any limitation in root growth and/or function will hinder the
uptake of water and nutrients, and overall tree growth will be adversely
affected.   Soil levels of water and nutrients which would normally be
adequate for tree growth may be so poorly utilized by the tree roots
that deficiencies appear.  The process of root extension may significantly
increase the water and nutrients which come in contact with the roots.
The ability of a tree to grow adequately in later years is dependent
upon the root framework established the first few years following planting.
Therefore, the extent of rooting in the first years of growth will
determine the growth which can be expected in later years.

     Root growth and function are dependent on several factors.  The
genetic character of the tree will partially determine the final root
form which is produced.   Silky and gray dogwood illustrated this by
achieving the greatest vertical penetration, while white ash produced
a shallow root system with a great deal of lateral rooting.  The other
species showed great differences in the root systems they produced.
                               303

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     The soil environment also greatly influenced the form and function
of the roots.  The root systems produced were all very shallow; the
deepest rooting observed was 35 cm.  The shallow rooting can be attributed
to several soil properties.  The soil had a very high soil strength
which, in part at least, provided mechanical impedance to root extension.
This is evident in that many of the roots were highly distorted and had
flat tips.  Other external, as well as internal, root characteristics
can also be attributed to mechanical impedance as was discussed previously.
High soil strength alone was not responsible for the reduced root systems,
as seen by the extensive lateral rooting in many cases.

     The water content of the soil also influenced the root systems
produced.  Low water content may prevent penetration, either directly
or because of increased soil strength.  Too much water may also limit
root extension and efficiency due both to excess water and to deficient
aeration in the root zone.

     Soil aeration also limited root penetration and function in the
study.  This is evidenced by the shallow root systems produced and by
the poor tree growth produced in spite of adequate fertility.  Many
dead roots occurred, as would be expected in a poorly aerated soil.
Greater tap root and overall root penetration also occurred on the
unprocessed as compared to the milled site, which was due to greater
aeration on the unprocessed site assuming that there was, as earlier
suggested, more gas production by milled refuse.

     Several other rooting characteristics were noticed.  Little increase
in vertical root penetration occurred from 1971 to 1972; however, some
increased in lateral rooting did occur over this period.  It was also
noticed that the amount of top growth produced by a given tree did not
always correspond to the amount and vigor of its root system.

     The grading necessary for preparation of the planting sites greatly
compacted the soil.  The amount of compaction occurring depended upon
the soil texture.  The topsoil which had only 12 percent sand was compacted
to a bulk density of 1.72 g/cc., while the subsoil with 40 percent sand
had a greater bulk density of 2.00 g/cc.  Apparently, the finer separates
filled in around the sand particles, and since the subsoil had a much
higher proportion of sand, it was compacted to a greater degree.  The
grading operation also reduced the total porosity to 16 percent for the
subsoil and 26 percent for the topsoil; it also caused the formation
of a crust on the soil surface.  The compaction caused by the grading
operation greatly influenced the moisture, aeration, and strength
characteristics of the soil.  Compaction reduces pore sizes in soils
so much that roots cannot make initial entry.  This is especially true
for coarse soils; but in finer soils the elongating roots may displace
the soil particles enough so that the roots may push through.  In this
study, although the soil was of a fine texture, the moisture conditions
interacted to prevent elongation.  Under high moisture conditions inade-
quate aeration probably prevented root elongation, while under low
moisture conditions a great increase in soil strength occurred to
limit elongation.
                                305

-------
                    Evaluation of Top Growth

     Aside from growth measurements and tree survival, certain charac-
teristics of the trees can be used to help evaluate their growth on the
landfill environment.  At the time of planting the unprocessed site,
much of the planting stock had been badly degraded by a two-week cold
storage period.  The effect of this cold storage period is difficult
to evaluate since the dry conditions existing on the unprocessed block
(U) at the time of establishment also must be considered.  The trees
were greatly affected and many died, while others lost much of their
terminal growth.  In most instances, this appeared to be due to de-
hydration.  Even after the initial establishment period, it was often
noticed that many of the leaves suffered severe dehydration during
dry periods.

     Another instance of the effect of prevailing conditions on tree
growth was seen in a depression in the planting site.  Due to uneven
settlement, a slight depression occurred on U which was filled with water
during periods following rains.  The trees planted there were very
stunted and had very poor survival (16 percent remained alive in 1972).
Apparently, the poor drainage greatly intensified the aeration problem.

     Aside from these problems, other visible symptoms were noticed
throughout the period of study.  Several apparent nutrient deficiencies
were encountered, particularly those indicating insufficient phosphorus
and nitrogen.  Insect damage was encountered to some extent each year.
Also, several lesions were caused by various parasitic organisms.  In
similar studies, it might be quite advantageous to include treatments
with various biocides to limit the effect of competing organisms.

Soil Physical Properties:

                          Soil Matrix
     Bulk density values (P^) determined on the two blocks (Table 65)
were very high compared to values which would be expected on soils of
similar textures, i.e., approximately 1.3 g/cc.  Average values for the
topsoil (1.72) and the subsoil (2.00) on the two blocks differ greatly.
Such a difference is due to differences in the soil particles of the
two type s .

     The particle density values (Ps) determined with pycnometers were
nearly the same for both the subsoil and topsoil (average 2.38).
Porosities were found to be 28 and 16 percent for the topsoil and subsoil,
respectively.  These values are far below the ideal porosity, which
is about 50 percent.

     High bulk density and low porosity have a great influence on soil
strength and therefore on the mechanical impedance to root elongation.
As discussed earlier, excavated roots were found to be restricted to
the immediate area in which they were planted in most cases.  High bulk
                                306

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densities often limit root growth and elongation.  No roots are found
at soil densities of 1.9 or above, while some clay soils stop penetration
by roots at just 1.6 to 1.7 g/cc.  The values found in the landfill
are definitely high enough to cause root restriction.  Although no
absolute limiting bulk density can be given, it is very likely that
the restricted root systems found on the landfill are due, at least
in part, to the high bulk densities.

     Results of penetrometer measurements show that the soil strength
at the one cm depth is generally low, probably due to the effects of
vegetation or because the dry crust cracked under the applied force
rather than flowing as it did in the underlying soil.  Lower depths
in both landfill profiles were so impenetrable that readings were
usually off scale.  Very little difference was found in the soil strengths
between the two landfill profiles despite their differences in bulk
density and texture.  The comparative data for the Arboretum soils
show values quite uniform throughout the profile, rather than low values
at the surface as in the landfill.  In both Arboretum profiles, values
are very much lower than those for deeper depths in the landfill.  Since
vegetation in the Arboretum is not restricted in penetration, as evidenced
by extensive root systems, it follows that values obtained there (less
than 3.7 kg/cm. ) are below the force most roots can exert to achieAre
penetration.  As indicated by the poor root expansion in the landfill,
the high penetrometer values denote strengths which are limiting to
root elongation.

                            Soil Water

     The compaction of the soil also had a great effect on soil moisture.
The soils were either too wet or too dry much of the second growing
season.  Soil compaction caused both a decrease in total porosity and
a decrease in the proportion of small pores.  The low total porosity
provided very little pore space for water, and the space which did
exist consisted largely of small pores.  Thus, the soil had both low
total water capacity and low available water capacity.  The compaction
also caused the formation of a crust which intensified the dry soil
conditions by causing much of the rainfall received to run off.  Low
rainfall normally was encountered when the plants required the most;
this, along with the low infiltration rate and the small amount of
available soil water, often caused the soil to be too dry for optimum
plant growth.

     Aside from these dry conditions, the tensiometer data also show
that the soil was saturated at many times during the growing season.
These periods normally occurred following heavy rainfall and at the end
of the growing season when evapotranspiration rates were low.  Large
amounts of rainfall were able to completely saturate the soil pores.
The low hydraulic conductivity and high moisture retention then caused
the pores to drain very slowly, greatly intensifying soil aeration
problems.
                                308

-------
                             Aeration

     Compaction, then, controlled aeration by affecting total pore
space, pore-size distribution, and water retention.  Since there was
little pore space, little space existed for air.  Because most of this
pore space was made up of small pores, the pores were quite often occupied
by water.  Besides displacing soil air, soil water also reduced the gas
diffusion rate of the soil.  The diffusion rate is proportional to the
fraction of total soil volume consisting of gas-filled pores.  The amount
of gas-filled pore space was found to be only 12 percent at a tension
of 15 bars, while at 0.3 bars (field moisture capacity) only 7.6 and
9.1 percent of the total pore space was occupied by air for subsoil
and topsoil, respectively.  Critical levels for gas-filled pore space
are 10 to 15 percent at field moisture capacity.  Thus, it is seen
that the trees are growing at near critical levels of aeration.

     This poor aeration situation is greatly worsened by the landfill
environment; the underlying refuse produces large quantities of carbon
dioxide and methane which diffuse upward and displace much of the
oxygen in the soil.  Thus, the quality of the soil air is quite unlike
that existing in "normal" field soils.  Gas samples showed that little
or no oxygen existed in the root zone on several occasions.  Methane
and carbon dioxide have not been proven to be toxic, but their presence
is very harmful because they displace oxygen which normally occupies
the soil pores (Table 66).  Thus, the gases produced by the refuse along
with the low amount of gas-filled pore space provide a great obstacle
for developing trees.  There may also be some problem with accumulation
of toxic substances due to the anaerobic conditions; however, this was
not investigated.

     In summary, it is quite obvious that soil aeration on the site is
very poor.  The production of carbon dioxide and methane by the refuse,
in conjunction with the low amounts of gas-filled pore space, provides a
great obstacle for growing trees.  Thus, it can be hypothesized that
the high mortality in the fall and winter of 1971-72 was in part due
to insufficient oxygen present in the rooting zone.

                           Temperature

     On several refuse cells without soil caps, it had been noticed
that snow would not accumulate due to heat production from the decom-
posing refuse.  Soil temperatures were monitored on the milled refuse
block to determine if growth might continue throughout part or all
of the winter months because of heat production by the underlying refuse.

     The temperature measurements, however, indicate that the refuse
had no detectable effect on the soil temperature.  The soil temperatures
reached - 16°C at one of the diodes, and the soil remained frozen for
several months of the year.  The data show that the shallower depths
were more responsive to the external environment than the greater depths,
as would be expected.  The refuse apparently had little effect on soil
temperature as witnessed by the later thawing of the deeper soil in
the spring.
                                309

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                                                            310

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      Another observation is that some of the trees may have been injured
or killed due to heaving in the winter months.  This is a distinct
possibility in that moist, dense soils such as these are quite subject
to heaving.  Although no trees were lifted completely out of the ground,
it is quite likely that some roots were injured due to frost heaving.

Soil Chemical Properties:

      The fertility status of most soils can be determined quite well
by the combined use of soil and foliar analyses.  Although neither is
completely reliable, together they usually point out any major fertility
problems.

      The values obtained in the soil analyses were compared to minimum
critical levels of soil fertility for three groups of trees based on
their nutrient requirements: microtrophs (least demanding), mesotrophs
(medium demanding), and megatrophs (highly demanding) (Wilde, 1958).

      Tissue analyses were made of foliar samples of white ash, jack
pine, and red pine taken from portions of the milled and unmilled plots,
from three different fertilizer treatments, and from reference plots
which, were used to compare values obtained for the three species.  The
foliar values were then compared to values given by Gerloff, Moore,
and Curtis (1964) for each of the above species.  Jack pine and red
pine samples were analyzed for N,P,Ca, and Mg, while white ash samples
were also analyzed for K, Fe, Sr, B, Cu, Zn, and Mn.

      Several trends in the availability of the nutrients can be seen.
First of all, the results of the analysis for N, P, K, Ca, Mg, organic
matter, and pH will be discussed.

      Using a combination of soil and foliar analyses, it was possible
to locate possible nutrient deficiencies existing in the landfill.
From the slow rate of growth and the high mortality of many of the
species, nutrient deficiencies might be expected.  The chlorosis of
many of the trees and abnormal coloration of others also leads one to
believe that some nutrients are deficient.  From the soil and foliar
analyses, however, it seems that it is probably physical limitations,
rather than chemical ones, which are causing the poor tree growth and
symptoms found.  Based on reference values used to compare the results
of the analyses, only a general index of possible deficiencies may be
given.  The levels for soils established by Wilde, for example, may be
sufficient under normal field conditions, but the primitive soil conditions
existing in the landfill might require completely different recommendations,
This is because of greatly different root zone conditions and the highly
anaerobic conditions existing much of the time in the landfill.
                                  311

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     In spite of these problems, certain conclusions may be drawn from
the analysis.  Nitrogen levels in the subsoil were near microtroph
levels while the topsoil was above the level established for megatrophs.
The chlorotic symptoms were seen in plants on both the topsoil and sub-
soil, so they were likely caused by something other than soil nitrogen
deficiencies.  This is supported by the high foliar levels found in
white ash, a species demanding relatively high levels of nitrogen.
Phosphorus was found to be in the mesotroph range for both topsoil and
subsoil in most cases, and foliar levels were near the prescribed levels.
Thus, phosphorus is probably not limiting tree growth in the landfill.
Potassium levels in the subsoil were in the mesotroph range while the
topsoil was above megatroph levels.  The foliar analysis for potassium
must be discounted because of leaching due to rinsing.  However, from
the soil analysis, it seems that potassium is not a limiting nutrient
either.  Calcium and magnesium levels are very high in the soil, so
it seems unlikely that they might be limiting.  There may be some problem,
though, with ion interaction between calcium, magnesium, and potassium.
There may also be some additional problems because of the somewhat
high pH.  Although the pH is not high enough to cause any problems
directly, it may cause some changes in the availability of some of the
nutrients.  The low organic matter content of the US and fertilizer
plots may also have caused some problems.  These plots are even below
the levels recommended for jack pine, which grows well on soils very
low in organic matter.  Even the topsoil and No. MS plots are well below
levels suggested for hardwoods.  Trace element levels are poorly understood,
But there may be some deficiencies or toxicities occurring because of
the anaerobic conditions and high pH present in the landfill.  The
fertility status of the landfill soils is generally adequate for tree
growth.  It appears that the factors limiting tree growth are more
likely physical than chemical.

Fertilization Experiment:

     The fertilizer experiment consisted of applying fertilizer packets
to the root zones of white ash, jack pine, and red pine to determine
their response to fertilization.  Some of the treatments included loose
fertilizer as well as packeted fertilizer.  The results of the experiment
show no height or diameter response to any of the applied fertilizer
treatments.  Although there was no growth response, neither was there
any increase in tree mortality due to fertilizer treatments.  Perhaps
the one-year period was to short to get much response, but it seems
quite unlikely that a response would occur at a later date.  Limitations
due to deficient moisture, deficient oxygen, or high soil strength quite
likely were responsible for the lack of response.  Because root systems
were limited in extent by these properties or because deficient oxygen
limited nutrient uptake by existing root systems, fertilizers were riot
utilized by the trees in sufficient quantities to cause measurable growth
changes.
                                312

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RECOMMENDATIONS

     In order to make recommendations concerning site preparation,
tree planting, and cultural practices to maintain trees on landfill
sites, it is necessary to make certain initial qualifications.  The
recommendations will depend upon the proposed use of the landfill,
the composition and preparation of the refuse, the kinds of soil materials
available, and the characteristics of the site.

     Most landfills are normally in an urban environment, and therefore
will probably be used for recreational purposes.  Thus, aesthetic rather
than economic considerations are normally most important.  However,
under different conditions, trees might also be planted for more economic
reasons.  Choice of a species, then, depends upon use since trees grown
for aesthetic reasons should be chosen primarily on the basis of survival
and appearance while overall growth is more important for economic purposes.

     The  refuse composition and preparation will also influence these
choices since the type and amount of gas production is determined by the
refuse.   This study showed significantly better survival on unprocessed
than on milled refuse; this was attributed to  less early gas production
by unprocessed refuse.  Refuse composition might also cause some dif-
ferences  in the type of gases produced and the rates of decomposition.
There may also be large differences in gas production over time; allowing
refuse to decompose for several years before covering and planting may
give the  trees a much better chance for survival.

     The  type of fill material available for use and the preparation
of the site for planting will influence the soil and tree species recom-
mended.   Economic considerations must enter in to determine how much
time and  expense should be expended to achieve the desired results.

     Fine-textured soils normally have the best aeration under low
moisture, but under high moisture conditions coarse-textured soils
normally  have better aeration.  Fine-textured  soils also have better
moisture  retention, so if drainage is not normally a serious problem,
a better  supply of moisture is provided during dry periods.  Coarse-textured
soils provide better drainage but are often too dry during periods of
drought.  Fine-textured soils normally also have the greatest soil
strength  except under very high moisture conditions.  A well-structured
medium texture soil such as a silt loam, either topsoil or subsoil,
will have adequate aeration but will still have enough moisture retention
to provide adequate moisture.

     The  fertility of the soil cover will depend on its origin; soil
analyses will give approximate nutrient levels and indicate whether
fertilizer may be helpful.  In later years, nutrient deficiency symptoms
and foliar analyses can be used to determine fertilizer requirements.
The use of topsoil rather than subsoil also calls for increased weed
control measures since a greater carryover of weed seeds normally accompanie
topsoil.
                                313

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     Once the type of soil is decided upon, the depth and method of
application must then be determined.  The results of this study showed
that the additional layer of topsoil increased both survival and growth
of the trees.  This increase was attributed to the extra 15 cm. of
topsoil providing greater aeration in the root zone.  The added layer
acted as a buffer between the tree roots and the refuse.  The somewhat
greater porosity of the topsoil also may have contributed to better
aeration in the root zone.  Soil depth may not be as important when
the soil is less compacted, but providing a thick soil layer seems to
be very good insurance against deficient aeration in the root zone.
Another reason for providing a thick layer of soil cover is that wind
throw may be prevented by giving the root systems adequate soil volume
in which to anchor themselves.  A method of application of the soil
cover should be used which will limit the amount of compaction as
much as possible.

     The determination of tree species to be planted will depend greatly
upon the proposed use of the landfill.  For recreation purposes, however,
species should be used which have relatively fast establishment and
low mortality; growth is normally not a major consideration.  Tree mortality
is normally greatest during this establishment period.  Of the species
used in this study, white ash, wayfaring tree, buffaloberry, and crab
suffered the least mortality during the first year; therefore, these
species may be the best suited for establishment.  White ash and buf-
faloberry also achieved greater growth the first year compared with
red and jack pine.  White ash is known to be rapidly established and
also grows well in dense soils.

     White ash and crab suffered the least mortality of any of the
species for the entire study period.  Past research has shown that white
and green ash, along with cottonwood, normally do very well under poorly
aerated soil conditions.  The rooting habit of white ash may be respon-
sible for its success; it produced primarily lateral roots and thus
concentrated its root system in the better-aerated upper soil layer.
Research on spoil banks has shown red and jack pine to be very reliable
evergreens normally, but the results of this study disagree.  This perhaps
is because of the dense soil and poor aeration; these pines quite likely
will grow much better under less compacted conditions.

     An additional factor of concern is that the tree roots will quite
likely enter the underlying refuse if the compacted soil conditions
are alleviated and better root growth occurs.  What will happen upon
their penetration is not known; however, it seems quite likely that
they will not penetrate the refuse to any extent because of probably
poor aeration, low moisture, and concentrations of toxic substances
in the refuse.  The trees will quite likely remain rooted in the soil
for the most part if the soil layer is of sufficient thickness.
                                314

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     A final consideration is that if a tree will be growing under less
than ideal conditions, it is usually best to plant relatively small
seedlings which can adapt their root systems to the rooting environment
that they are planted in.  However, there are certainly some situations
in which larger trees would be more desirable for planting.  Planting
larger trees would greatly speed their growth to a size at which they
would be more useful from an aesthetic and functional viewpoint.  Larger
trees should be planted in large planting holes and the holes should
be backfilled with a rich soil having good structure.  Planting of
small seedlings may be done directly into the soil cover as done in
this study, but the addition of a mulch material along with sufficient
fertilizer will undoubtedly increase growth and survival.  The mulch
will substantially increase the water-and nutrient-holding capacity of
the soil.  Fertilization should be done on the basis of a soil test
since no benefit will be derived if the soil levels are already adequate.
Itrigation may also be necessary to obtain adequate survival, especially
the first year.

     In summary, a medium texture, well-structured soil material should
be applied to the refuse using a method which limits compaction as much
as possible.  The depth of soil material should be as great as is econ-
omically feasible, providing adequate soil volume for root expansion
and a buffer between the root system and gases produced by the refuse.
Species to be planted should have the ability to develop a lateral root
system with diffuse branching; white ash and crab developed such a root
system in this study.  Relatively small seedlings should be planted
in planting holes which have mulch material and fertilizer packets added.
In cases where the planting of larger trees is more desirable, planting
holes should be backfilled with topsoil and a mulch material to provide
a good initial root environment.
                                315

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                         OTHER VEGF/ij\T10N

     Unless an uncovered cell of milled refuse ir, continually worked,
volunteer vegetation will develop in one or two years after placement.
During the summer of 1968, a diverse plant community, ranging from
weeds to garden vegetables (Figure (--:~) ) to trees, became established
spontaneously on all the milled uncovered cells at the Olin Avenue.
site.  This growth may have been due in part to seeds in the refuse
itself.  Heavy plant growth has continued on the milled cells in  sub
sequent years.  In fact, the vegetation on the milled refuse cell is
so dense that it is difficult for an observer standing on an old milled
refuse cell to see that he is indeed on refuse and not on soil  (Figure!

     Also ir 1968, a slimy growth was noted on many of the milled
uncovered cells.  It persisted throughout the summer and reappeared
the next year.  It was identified as a slime mold, FuH_gp J;C£t_i£a,
which is commonly found in heavily \-7ooded areas.  It grows on material
of high cellulose content.  This slime mold is not a threat; to  public
health.
                               316

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                   VIII OTHER OBSERVATIONS

VIII-A - Fire

INTRODUCTION

      A series of tests on the fire hazards from milled refuse in
a landfill was conducted in August 1969. These tests were performed
by the Madison Fire Department at the Olin Avenue Landfill.

      Ignition of the milled material in all tests was from heat sources
likely to be encountered under normal landfill conditions.  Test
situations simulating grass fires, airborne flying embers,  and acci-
dental ignition of spilled fuel oil were carried out on milled refuse
cells of various ages.  The fires that occurred as a result of these
ignition sources were mainly superficial and allowed for close ap-
proach (Figure 110) to observe both the rapidity of spread and
the intensity of heat generated.  One special test was conducted
to obtain some data relative to burning conditions in the interior
of a storage cell. This test was not intended to simulate a realistic
condition.

      Three experimental milled refuse cells were used for the
test fires.  Two of the  cells were over one year old and the third
was a special cell constructed within  a month of the time the fire
tests were  conducted.

      The  development of a suitable means of fire  control and extinc-
tion was also to be determined from these tests.

      Following are the reports and analyses of the various fire
tests on milled refuse cells.
                              319

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•   -

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I .   wind-Blown F.
--d  Refuse Land Hi I

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                   VII.  MADISON FIRE DEPARTMENT
                               FIRE TEST

 Location   Refuse Reduction Plant-Olin Avenue   Date  August 18, 1969	

 Fire Type  Fuel Spill Simulation	Cell Number  35    Cell Depth 5h Ft.

 Cell Size  88' x 98'   Cell Formation Date April 1, 1968  Temperature  74 F.

 Location of Fire on Cell E. end-midpoint top   Relative Humidity  66%.	

 Ignition Start Time  9;08 A.M.         	   Burning Time  45 Min.
 Extinguishing Method  Burned Out	Wind Velocity-Natural  6   M.P.H.

          FIRE: TEST NUMBER ONE                        Artificial None M.P.H.

 COMMENTS:

          The first test fire was one intended to simulate a fuel spill as
a result of automotive equipment working on top of the cells.  Fuel containing
a ratio of 4 gallons of diesel fuel to 1 gallon of drained crankcase oil
was used.  An area of approximately 5' x 5' was covered with the fuel.  A
small amount of gasoline was poured at one corner of the spill and ignited.
The fire burned rapidly at first, generating considerable amounts of heat.
When the larger flames died down the remaining fire consisted of flames
about 6 inches in height being fed by the vapors as a result of the fuel
spill.  When the milled material was agitated, larger flames again appeared.
This action seemed to indicate the milled material had the ability to trap
the fuel vapors at levels below the surface fire limiting the volumes
dissipated.  The agitation of the material was continued until no fire could
be sustained by this method.  The fire burned out completely in 45 minutes.
Examination of the burned area after the fire was out indicated negligible
penetration of the fire.  Perimeter extension of the fire was about 6 to 12
inches.  The fire remained entirely on the surface and appeared to burn
only the very small particles of combustible material lying on the surface.
Very little ash was present and the burned area had a charred appearance.
During the fire the wind had little or no effect on the spread of the fire.

CONCLUSIONS:

          Because of the length of storage time, compactness of the milled
material, and the moisture content within the cell it appeared unlikely
that a fire started by an incident of this type would be capable of involving
the stored milled refuse to any degree.

OBSERVERS:  Warren Porter, John Tappen, Douglas Bailey, Donald Muggins,
            Vincent Geier
                                  322

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                        MADISON FIRE DEPARTMENT
                               FIRE TEST

 Location  Refuse Reduction Plant-Olin Avenue    Date August 18, 1969	

 Fire Type simulated Flying Embers      Cell Number 16     Cell Depth 5*3 Ft.

 Cell Size 88' x 98'     Cell Formation Date April 1, 1968  Temperature 74  F.

 Location of Fire on Cell Midpoint-top	 Relative Humidity  66%	

 Ignition Start Time	9;52 A.M.	Burning Time  5h Hrs.	

 Extinguishing Method  Burned Out	Wind Velocity-Natural  5  _M.P.H.

      FIRE TEST NUMBER TWO                           Artificial None  M.P.H.

 COMMENTS:

          The second test fire was a simulated flying embers exposure type
incident.  Approximately 5 pounds of charcoal was ignited in a separate
container and when all the coals were glowing they were placed on the
milled material.  These coals burned for a period of 5*i hours.  Examination
of the burned area at this time showed no indication of any penetration
vertically in the milled refuse.  Horizontal spread was limited to several
inches directly adjacent to the coals.  The coals did not have the ability
to ignite the very small pieces of combustible material on the surface.
This produced sporadic flames several inches in height but of very short
duration.  The wind had no effect on this fire.

CONCLUSIONS:

          Because of the length of storage time, compactness of the milled
material, and the moisture content within the cell, it appeared unlikely
that a fire could be started by an incident of this type.

OBSERVERS:  Warren Porter, John Tappen, Douglas Bailey, Donald Huggins,
            Vincent Geier
                                 323

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                        MADISON  FIFE  DEPARTMENT
                              FIRE TEST

 Location   Refuse Reduction Plant-Olin Avenue    Date   August 18, 1969
                                                    Mill
 Fire  Type  Simulated Grass Fire	Cell  Number Spoil  Cell  Depth 5^ Ft.

 Cell  Size  50' x 98'    Cell Formation Date  June 1, 1968   Temper attire 74  p.

 Location of Fire on Cell  S. E._Corner-Base     Relative Humidity  66%

 Ignition Start Time  10:21 A.M.	Burning Time Approximately 4 jiours

 Extinguishing Method Water (100 gallons)  wind Velocity-Natural  4  ^JM.P.H.

          FIRE TEST NUMBER THREE                     Artificial_8	M.P.H.

 COMMENTS:

          The third test fire performed was a simulated grass fire.  During
the time of structure of the cells, the sides are naturally formed at
approximately a degree angle of 60.  It appeared at the time of burning a
certain erosion process had taken place during the storage period and the
finer materials had washed away and only the more coarse materials remained.
This action formed horizontal ridges or protrusions of materials on all
sloped sides.  The top surface of the cell was very compact in relation
to the material forming the sides of the cell.  Two bales of hay were spread
at the base of the milled material cell.  Fans were set up to increeise the
wind velocity.  This was done because the fire was to be ignited in vthat
was a. gully formed by the adjoining cell and natural wind velocity at this
location was negligible.  This procedure was continued for 30 minutes.  The
hay in the center of the bale was damp and approximately one quart of
gasoline was used along the farthest outside edge of the hay for rapid
ignition of the total edge.  Upon ignition the fire spread through the hay
and up the slope of the cell and traveled across the horizontal surface at
the top of the cell, burning off grass that was naturally present at this
time of year.  This natural grass failed to ignite the milled material.  The
fire traveling up the vertical slope ignited the ridges of the milled material
and did sustain combustion.  Flame propagation was not of great dimensions but
did continue visibly for a period of one hour.  At this stage the fire
was definitely a smouldering type, giving off considerable quantities of heat.
The fire continued to burn  for a period of 4 hours before extinguishment
took place.  Examination of the burned area revealed a spread of fire
beyond the hay placement of about 6 feet in length and maintained the
approximate width of the hay placement.  Depth of fire penetration in
isolated spots reached a maximum depth of about 9 inches.  Generally the
burn penetration was negligible and consisted, to a large degree, of surface
material charring.  Extinguishment was a relatively simple matter using a
quarter  inch nozzle and approximately 100 gallons of water after 4 hours
of burning time.

CONCLUSIONS:

          It would appear that a fire starting at the base rf this cell
would have the ability to burn in a vertical directicr to*'.?"' the 'oc  •
the cell.  Moisture content would restrict deep penelrati-,-•     f-. e   t
stored material.  Green natural cover such as grass or  ,-•        '     ^  •-• *
                                 324

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                        FIRE TEST NUMBER THREE

                         SIMULATED GRASS FIRE
eliminate any possible spread of fire at the top horizontal surface
of the material cell.  From a fuel source hazard standpoint, the
stored milled material of this age would have to be considered as slight.

OBSERVERS:  Warren Porter, John Tappen, Douglas Bailey, Donald Muggins,
            Vincent Geier.
                                 325

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                        MADISON  FIRE  DEPARTMENT
                              FIRE TEST

 Location  Refuse Reduction Plant-Olin Avenue   Date  August 18,  1969
 Fire Type  Buried Heat Element          Cell Number  15    Cell  Depth
 Cell Size 88* x 98'    Cell  Formation  Date  April 1, 1968  Temperature 74  F.

 Location of Fire  on Cell  Center (3'  Depth)      Relative  Humidity _ 66%

 Ignition Start Time  11; 10 A.M. _ Burning Time   Undetermined  _

 Extinguishing Method _ None  _ wind Velocity-Natural __ M.P.H.

      FIRE TEST NUMBER FOUR                          Artificial __ M.P.H.

 COMMENTS :

          A final test was performed in an effort to gain some data on
burning situations within the milled refuse.  Previous gas analysis made
on the various cells at various levels  indicated that at times sufficient
oxygen was present to sustain combustion.  Temperatures thus far recorded
have reached a high of 140 degress F. at certain levels.   In order to
generate  the necessary ignition temperature within the milled refuse, an
electric heating element was placed at a depth of three feet.  The element
used was  an 1175 watt resistance type element, and was placed directly
on the milled material.  Approximately eight inches of milled material
was spread over the top of the element and compacted.  At this point a
thermocouple was placed to record temperatures within the milled material
that would be produced by the heating element.  More milled material was
applied and compacted at regular intervals until the top elevation of the
cell was  reached.  A portable generator was used to supply the energy
necessary for the heating element.  The generator was run for a period of
four hours.  All during the time the heating element was energized, attempts
were made to record the temperature of the milled material at the thermocouple
without success.  This later appeared to be a result of too great a distance
between the heat element and the thermocouple.  The buried element was left
untouched for a period of twenty hours  at which time exhuming took place .
Removal of the material from above the element was carefully checked at
all levels for heat and smoke indications.  At approximately two inches
above the element, charring was noticeable.  A certain amount of heat
was present but was not of the degree to be uncomfortable to the touch.
No smoking of the material was in evidence.  Complete uncovering and removal
of the element showed a charring of approximately two inches in all directions
from the  element outline. ,  Examination of the charred material revealed it
to be of  a brittle nature .

CONCLUSIONS::

          Evidence gained with this test indicates a deficiency of oxygen at
levels within the refuse necessary to support combustion.  This test was not
intended  to simulate a realistic condition, but rather to determine if burn !-•••.
could be  accomplished and sustained within a cell.

OBSERVERS:  Warren Porter, John Tappen, Douglas Bailey, Dor'" - Huoqrrs
            Vincent Geier        ,_,

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                        MADISON FIRE DEPARTMENT
                               FIRE TEST

 Location   Refuse Reduction Plant-Olin AVenue   Date August 26, 1969
 Fire Type  Fuel Spill Simulation	Cell Number SpecialCell Depth 5 Ft.

 Cell Size 64' x 91'    Cell Formation Date Aug. 8, 1969   Temperature 61  F.

 Location of Fire on Cell S. W. end - Top	 Relative Humidity   84%

 Ignition Start Time   8:55 A.M.              Burning Time	11 days    __

 Extinguishing Method   Water	Wind Velocity-Natural  2 .5_M. P. H.

        FIRE TEST NUMBER FIVE                        Artificial  13  M.P.H.

 COMMENTS:

          Where as  the previous fire tests were accomplished on cells stored
for over a period of one year, the following tests were made on a cell developed
within the last two weeks.  Again the ignition methods used were heat sources
likely to be-encountered under normal storage conditions.  Burning characteristics
of the material along with the development of fire control methods were also
included as part of these final tests.  Fuel used on this test was the same
as that previously used.  Area covered by the fuel was 40" x 66".  Upon
ignition the fire burned rapidly where the fuel had been spilled, and generated
considerable amounts of heat,  it became very apparent that because of the
lack of moisture content of this newer cell and the small amount of settling
and compacting, that this fire was capable of spreading readily.  After
approximately five minutes, the burning area had increased in size, and involved
an area five times as great.  During the course of the fire spread very little
flame was visible, except in the initial spill area.  Because of the lack of
natural wind we again set up fans to create a wind situation.  Twenty minutes
after ignition the fans were started,  wind velocity was measured at 13 M.P.H.
To some degree this did have the effect of spreading the fire faster.  Because
of the use of heavy tracked vehicles during the forming of the cells, ridges
were created by the tracks and the fire did not spread readily across these
indentations.   Although this did appear to be an obstacle in the spreading of
the fire, it eventually did burn across.  The fire continued to spread laterally
in all directions as well as burning downward.  At this point it was very
obvious the fire would not be restricted to a surface fire and burn itself
out as had happened in the older cell.  When it appeared that all flame action
had ceased, flames could be made to appear by walking through the area of the
original spill of the fuel.  This apparently was caused by vapors trapped below
the surface of the material.  At this stage of the fire a limited amount of
water was used on the fire in certain areas to determine how difficult it
would be to extinguish.  Eighty gallons of water through a quarter inch tip
was used with good results.  Although complete extinguishment was not accom-
plished because this was not desired, it was felt the fire could have been
completely extinguished with a limited amount of water.
                                 327

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                         FIRE TEST NUMBER FIVE
CONCLUSIONS:

          It is possible to ignite the surface of this milled refuse
from an outside source such as a fuel spill fire.  Once a surface fire
has started the fire will spread throughout the entire cell.  The two major
facton which appear to effect a surface fire and the subsequent spread of
the fire are the moisture content of the milled refuse and the compactness
and settling of the cell.  Wind did not appear to be a large factor because of
the lack of flame.  Smoke initially would be a nuisance factor but is
drastically diminished as the combustible material on the surface is
consumed by the fire.

OBSERVERS:  Donald Huggins, Vincent Geier
                                 328

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                        MADISON FIRE DEPARTMENT
                               FIRE TEST

 Location  Refuse Reduction Plant-Olin Avenue    Date August 26, 1969	

 Fire Type  Simulated Ember Exposure    Cell Number SpecialCell Depth 5 Ft.

 Cell Size 64' x 91'    Cell Formation Date Aug. 8, 1969   Temperature 73  F.

 Location of Fire on Cell  S. Side Top	Relative Humidity  76%	

 Ignition Start Time   9;55 A.M.	Burning Time  11 days	

 Extinguishing Method  Water	Wind Velocity-Natural 2.5 _M.P.H.

       FIRE TEST NUMBER SIX                          Artificial None M.P.H.

 COMMENTS:

          Charcoal again was used to simulate a flying ember type of heat
source for this test.  The charcoal after being placed on the milled material
was sufficient for ignition to take place.  First indications were that the
spread would be slow.  After a five minute burn the fire was observed as to
size and again at ten minutes.  During this time the area of involvement was
increased five fold.  All during the burning, it was difficult to observe
much flame propagation.  As in other tests the flames were sporadic, several
inches in height and of very short duration.  Although the fire was spreading
in all directions, no attempt to extinguish it was made at this time.

CONCLUSIONS:

          Same as on test fire number five.

OBSERVERS:  Donald Muggins, Vincent Geier
                                 329

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                        MADISON FIRE DEPARTMENT
                               FIKE TEST

 Location  Refuse Reduction Plant-Olin Avenue    Date   August 26,  1969
 Fire Type  Simulated Grass Fire	Cell Number Special Cell Depth 5 Ft.

 Cell Size  64' x 91'    Cell Formation Date Aug.  8,  1969   Temperature 73  F.

 Location of Fire on Cell W end Base	 Relative Humidity	76%	

 Ignition Start Time  10;20 A.M.	Burning Time  11 Days	

 Extinguishing Method Water	Wind Velocity-Natural  2.5_M.P.H.

        FIRE TEST NUMBER SEVEN                       Artificial_6	M.P.H.

 COMMENTS:

          Because of the difficulty experienced when executing Fire Test Number
Three, relative to the hay being damp, we immediately on arriving at the site
spread the hay on the ground to allow it a period of two hours to dry.  The
quantity again was two bales, spread loosely at the base of the cell.  Lack
of appreciable wind velocity made the setting of fans a necessity if any
determination of wind being a factor in the spread of fire in this material
was to be evaluated.  Ignition of the hay was made in the center of "the spread
material.  The fire spread through all of the hay rapidly, producing flames
of from four to five feet in height.  Large quantities of white smoke soon
appeared and indicated that the hay was not completely dry.  Within a period
of ten minutes all flaming action in the hay had disappeared and only a
smoldering action remained.  The hay fire was sufficient to be an ignition
source for the stored milled material.  Because of the wind involved, the
fire spread relatively fast across and up the entire end slope of the cell.
When the fire reached the top of the cell, its progress was approximately the
same as that involving the other two test fires on this cell.

          All three test fires conducted on this cell were allowed to burn and
within a period of five hours the entire top surface of the cell was involved.

CONCLUSIONS:

          Same as on Fire Text Number Five.

OBSERVERS:  Donald Muggins, Vincent Geier
                                  330

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                             SPECIAL CELL FIRE ANALYSIS


                 Test fires numbered five, six, and seven, which were conducted on

August 26, 1969 involving the special cell were allowed to burn in an effort to gain

data relative to rate of spread, heat generated, smoke and flame conditions, and fire

control and extinguishment methods.  Burning was allowed to continue for a period of

eleven days.

                 On the day the fire was extinguished, September 5, 1969, the physical

makeup of the cell consisted of a top layer of light ash six to eight inches in depth,

followed by a three to four inch layer of charred material, with a total burned

depth of from nine to twelve inches.  Observations made prior to the time of extin-

guishment indicated that the combustion process was retarded as time progressed and

the fire became deep seated.  The spread was in a very uniform manner and formed no

pockets within the cell.

                 On August 27, 1969 temperature readings were taken at various locations

and depths on the cell.  Surface temperatures on the top of the cell were 405 degrees

Fahrenheit.  At a depth of three inches a temperature of 505 degrees Fahrenheit was

recorded and at six inches a temperature of 200 degrees Fahrenheit was present.  Surface

temperatures on the windward side on the sloped bank were recorded at 604 degress

Fahrenheit, and in the same location on the leeward side at 315 degrees Fahrenheit.

Temperature readings were again taken on September 4, 1969 on the top surface of the

cell in approximately the same location that the first reading was taken.  The surface

temperature was recorded at 180 degrees Fahrenheit and at a depth of eight inches a

temperature of 580 degrees Fahrenheit was recorded.  At this point it became evident

that the temperatures recorded were well within the ignition temperatures of the

greatest percentage of the components making up the milled refuse, and that combustion

would continue.

                 Smoke and flame conditions were observed on all days while burning

took place.  No flame was visible at the end of the first day that ignition was started.

While digging ir *:h-? pi!« to determine burn depth, the instant the ash cover was

removed and the material turned over, it burst into flame.  This was an indication
                                        331

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that the rate of combustion was slow and that the absence of sufficient oxygen was




the prime factor in restricting the fire to a smoldering type.  Flame flare up was




visible in isolated instances when a material with a rapid burning rate, such as some




forms of plastic reached its ignition temperature.  All during the burning period,




only moderate wind velocities were recorded.  It was felt that if severe winds had




been prevalent, that the loose fly ash covering the cell could have been dissipated




and that flame propagation would be inevitable.  Limited amounts of smoke was present




at all times, and these quantities appeared to diminish as the fire burned longer.




The smoke came to the surface through minute crevices and apertures, and at times




appeared to be a belching action.  Whenever the surface was disturbed, much larger




quantities of smoke were apparent.  Because of the lack of oxygen for complete com-




bustion of the material, samples of the smoke at the surface level were taken to




determine the carbon monoxide concentrations being generated.  In eight different




tests made at different locations on the cell, the largest concentration in any one




test was ,1%.




                 Initial control and extinguishment of small fires could be accomp-




lished as stated in Fire Test No. Five.  Because of the availability of the milled




material being produced, it was felt that extinguishment by smothering, using this




material as the smothering agent could be a possibility.  A full load of approxi-




mately twenty two yards was dumped on the cell and was spread by a bladed tractor




over an area 15 ft x 50 ft.  This took place approximately four hours after ignition.




The cover varied in depth from six to twelve inches.  When the covering was completed,




the area showed no visible indications of fire or smoke.  After a time lapse of




approximately thirty minutes, smoke issued from the covered area in isolated spots.




Three hours later the entire covered area was again involved in fire.  No merit




could be fixed to this method of extinguishment.  Final extinguishment of the in-




volved cell was accomplished using two one and one eighth inch straight stream




nozzles each having a nozzle pressure of fifty p.s.i.
                                        332

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                 These two nozzles were flowed for a period of two hours at which txin-



complete extinguishment was attained.  The method of operation was to place both line;



at the windward end of the cell and work slowly across the top of the cell.  It was



very obvious when complete extinguishment had been attained in an area so that lines



could be advanced.  No difficulty in extinguishment was experienced in any one



section over another.  Complete soaking of the burning layer of material was



essential for extinguishment.  There appeared to be very little run off of water



from the cell during the extinguishment process.



                 Because all facets of this report are still under study by the



Madison Fire Department, no recommendations relative to methods of safe storage have



been made at this time .  Studies of the hazards involved in the milling process will



have to be made to determine any degree of severity.




                                          Respectfully submitted,

                                             ,     s~
                                       1   ]     s1/      *  1

                                      U'^AfrtK.* ./^-Hs^ti^ y •, ft2tii

                                        i                 ^
                                          Captain Vincent J. Geier,

                                          Superintendent of Training,

                                          Madison Fire Department
DATE:  October 3, 1969                 333

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VIII-B - Blowing, Odor,  Esthetics        ;

BLOWING

      Blowing litter has been one of the most persuasive objections
to some of Madison's sanitary landfill operations for unprocessed
refuse  (Figure  ill).  The extent of the problem depends on wind
direction and speed as well as exposure of the working face to the
wind.  For example, unprocessed refuse dumped at one of Madison's
other landfills may be caught by the wind immediately and blown
over the boundary fence.  On occasion,  special work details have
been sent out on Saturdays to pick up litter from the lawns of homes
near landfills.  In 1969 alone, some $22,000 was spent for manpower
to control and pick up blowing paper from landfills.  Even 15-foot-
high movable fences placed downwind from the working face have
failed to solve the blowing problem associated with landfilling unprocessed
refuse.

      As noted elsewhere in this report, various grate sizes and
hammer patterns were used to obtain a particle size which would
reduce blowing problems at the landfill. With properly ground
milled refuse, the blowing problem was  found to be minimal.  Madison's
Director of Public Works has stated that  this  feature alone justifies
a milled refuse operation. Landfilling has been carried out with
milled refuse during winds up to 60 mph on a flat site with only
minor problems.  Those blowing problems that are experienced
are usually due to sheets of plastic, which are not thoroughly shredded
in the mill  and therefore tend to roll across the fill surface. Such
items do not become airborne, and are readily caught by low fences.

      Three factors may be given to explain the lack of blowing
of milled refuse.  First, particles  of milled refuse tend to become
entangled in each other so that they are  disharged in clumps rather
than as individual particles which can be blown away.  Second,
the small surface area of individual particles of milled refuse provide
a small target for the wind.  This  is in contrast to a page of newsprint
which, caught in a high wind, acts like  a sail and blows for long
distances.  Observations at the landfill site have confirmed that
bits of freshly milled refuse blow  only a few feet before coming to
rest.  Finally, in a landfill, a crust similar to papier mache over
the surface of milled refuse in a few weeks.
                              334

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ODOR

      The Olin Avenue Landfill is bounded by a playfield on one
side, residential areas on two sides, and the Dane County Coliseum
on the other. The Coliseum is a 10,000-seat facility.  Thus, there
was a large "audience" available to make known their complaints
if any odor problems developed. Fortunately, no such problems
have occurred.

      Lack of unpleasant smells is one of the most notable features
mentioned by visitors to the milled refuse landfill areas.  Project
personnel theorize that ready access to air and the accompanying
drying of the surface of the milled refuse cells produce an aerobic
buffer zone which infiltrates odors produced deeper in the cells.
In support of this theory, it was noted that by digging 3 to 6 inches
into a cell, one begins to detect odor typical of decaying refuse.
Upon digging a foot or more, a most disagreeable odor is produced.

      Some minor odor problems have developed during unusually
wet periods when, due to improper drainage of depressions between
the test cells, ponds of water formed. These problems have been
readily solved by filling the low areas or by providing drainage
channels.
ESTHETICS

      Milled refuse is relatively homogeneous and looks like over-
sized confetti.  Viewed from a distance, milled refuse is nondescript
and unobnoxious since it contains no large recognizable items.
Of the thousands of lay people who have viewed the Olin Avenue
Landfill, no one has objected to the sight of uncovered milled refuse.
                             335

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                 IX.  EUROPEAN OBSERVATIONS

                          INTRODUCTION

     The practice of milling or pulverizing solid waste for landfill
disposal has only recently been introduced into the United States.
Other than the fev/ grinders found in composting plants and bulky
waste reduction facilities, this country has had little or no
experience with the machinery involved in milling.  Aside from
the Madison operation, in which both authors are involved, even
loss experience is available on placing milled refuse in a landfill.

     In contrast to the situation in the United States, the
literature suggests that pulverizinq solid wastes for landfilling
without daily cover is accepted and widely used in Europe.  In
fact, documents citing European experience with this method are
largely responsible for the concept being implemented at Madison
and, more recently, at other United States installations.  Among
beneficial features of milled refuse cited in these documents
are the increased density of milled refuse, the ability to operate
a landfill without nuisance or hazard to the surrounding area, the
lack of need for daily soil cover, and improved acceptance by the
public of milled over unprocessed refuse in land disposal.

     The Refuse Milling Project at Madison - representing the
combined efforts of the City of Madison, the University of
Wisconsin-Madison, the Heil Company of Milwaukee, and the Environmental
Protection Agency - has as its goals:  evaluation of the economics
and equipment of a refuse mill, evaluation of milled refuse itself,
and evaluation of milled refuse used in landfill.  Five years of
operating experience, practical field evaluations, and detailed
studies dealing with specific aspects of the milling facility and
the landfill iiave resulted from this project.  Most questions about
transferring European observations to this country and about the
acceptability of the concept in the United States have been answered
adequately.  The only major questions remaining concern long-term
results at the landfill site and transfer of information developed
at Madison to other locations having different refuse compositions, climates
and operating conditions.  It './as apparent to the authors that the nuickest
way to nather information on these broad questions was to review the
experiences of European refuse milling installations, emphasizing those
which place the milled product in a landfill for disposal.

     On May 31, 1972, the authors departed on a 27-day study tour
of European refuse milling installations during which 22 sites (Appendix
0)  • were visited and discussions were held with ?7 persons having broad
experience in the design and evaluation of millirn facilities and milled
refuse landfills.  Because of the ease of communication, the many
references in the literature, and the long-term use of milled refuse
for landfill in the United Kingdom, it was decided to spend a major
nortion of the tour in "reat Britain,  Accordingly, 13 person were
interviewed and 11 sites visited durino the 10 days snent in Englr.n^1 ^nd


                                336

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Scotland.  This portion of the tour was arranged by Messrs. Sumner and
Green of the Department of the Environment Offices in London, based on
their extensive experience with solid waste management throughout the
United Kingdom.  The tour was balanced by including both operating and
regulatory personnel as well as machinery representatives of major
manufacturers.  Installations known to be trouble free, and others
known to have pro!)!ems of some sort, were included.

     Three persons were extensively interviewed and five sites (plus
one unprocessed refuse fill) were visited in France.  /U though solid
waste milling is widely practiced in France, the lack of both time and
direct communication cut our stay in that country.  The French sites
were chosen l>y the authors based on the literature and personal contacts.

     As refuse milling for landfill disposal does not appear to be as
widely practiced in Germany or Switzerland as in England and France,
only two milled refuse sites and three persons were visited in each country.
One unprocessed refuse fill, picked on the basis of its reputation as a
good "sanitary landfill", was also visited in each country.  The milling
sites were selected through personal contacts andlliterature references.
The unprocessed refuse landfills were selected after discussions with a
city engineer in Germany and a federal official in Switzerland.

     The milled refuse sites visited in the United Kingdom, France,
Germany, and Switzerland represent only a fraction of tiie number of
installations in these countries, and an even smaller fraction of
such installations throughout all of Europe.  Our estimate of the
number of installations in those countries visited alone is 150,
where nearly all of them landfill all or a major fraction of the
milled refuse produced.  This figure is based largely on lists of
installations supplied by major equipment manufacturers.

     Indications are that those sites visited provided a realistic
cross-section of all the installations.  Further, much of the
information obtained during the latter portion of the study tour
was repetitious of earlier visits.  Finally, and most importantly,
the knowledge of many of the persons interviewed extended beyond
one site, or even one country.  For example, in England, France,
and Switzerland time was snent with federal and regulatory personnel
•who had broad knowledge of installations in their countries and
elsewhere and could talk with authority about the successes and
problems experienced,  filso, time was spent with representatives of
equipment manufacturers who were acnuainted in detail with instal-
lations of thoir manufacture throughout Furone.  These people were
particularly candid in their remarks about landfilling milled refuse,
and were quick to point out where in their opinion problems had been
experienced and the reasons for such problems.
                                337

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                                    PROCEDURE

              Typical  site visits  and interviews  v;ere  conducted  in  the  foil owing
         manner.  Almost without exception  the  chief administrator  of refuse
         disnosal  activities, usually at the equivalent  level  of Director  of
         Public Works  in the United  States, was  informed  about the  impending
         visit.  The contact was made by a  representative of  the manufacturer  of  the
         equipment in  use or by national governmental  officials.  An equipment
         representative was present  during  approximately  half of the site  visits
         to act as interpreter and/or to provide  an introduction to the people
         to be interviewed.  In addition, the representatives commonly  provided
         background information on the installation to be visited and unusual  or
         important features to be  noted during  the visit.

              The administrator or his appointee  was first provided a copy of  a
         paper written recently by the authors  describing the Madison refuse
         reduction project.*  This was done to  establish  quickly that the  visitors
         were knowledgeable in the practice of  refuse  milling and to initiate
         communication with the person being interviewed.  Otherwise, no information
         about experiences at Madison was volunteered  until near the close of  the
         interview.  The purpose of  this procedure was to insure that discussions
         represented the administrator's true opinion  of  his  operation  and the
         milling concept in general.

              A copy of the proposed outline for  this  report  was  provided  to the
         person being  interviewed  to act as a guide for  discussion  and  to  make
         the point immediately that  the purpose of this  visit was to learn about
         the landfill, not the equipment.  The  point was  made that  it is the
         landfill  which is of most concern  in the United  States  and that the purpose
         of the trip was to learn  from their experience  in operating such  a landfill.
         It commonly took 2 to 3 hours to discuss the  points  A through  I in the
         outline,  after which a tour of the installation was  made,  usually tain'no
         another 1 to  2 hours.

              The  purpose of the tour was to look for  negative aspects  of  the
         operation, often to the surprise and perhaps  dismay  of  the person being
         interviewed.   Thus, the site visits amounted  to  hunts for  flaws in the
         landfill, whether they be signs of rodents or insects,  odors,  blowing
         papers, leachnte problems,  or others.   It is  significant to note  not:
         only that were most persons tolerant of  the rather negative questioning,
         emphasizing problems rather than successes, but  also that  they often
         seemed to be  amused or bewildered  by some of  the questions dealing
         with matters  '/Inch to them  were not an  issue  worth discussing, for
         example,  the  presence of  a  few flies on  the landfills on some  occasions

*Ham,  R.  K., W.  K.   Porter,  and  J.  J. Reinhardt.   Refuse  milling for
      landfill disposal.   Pt.  1.  Public  Works,  102(12):42-47, Dec,  1971

Ham,  Porter,  and Rienhardt.  pt.  2.  Public Works, 103(1)  : 70: 72,  Jan.  1972.

Ham,  Porter,  and Reinhardt.  pt.  3.  Public Works, 10 3 (2)  : 49- 54 ,  Feb.  1'* .


                                         338

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was alv.'ays acknowledged; however, the level  was felt to be so lev/ as
not to warrant any concern on their part and certainly not to be an
issue for detailed discussion vith forciqn visitors.

                     RESULTS Ann Discussion
     It nust be remembered that the results cited in this section are
based on observations nade during one visit to a small fraction of the
total number of European installations v.'hich landfill milled refuse
and to an even smaller fraction of the people having experience in the
subject.  Remember, also, that comments in this report are not meant
to be derogatory or fault-finding with respect to regulatory agencies
or facility designers or operators.  In most cases, where orobTerns were
apparent, the persons responsible were well aware of the situation but,
due to factors beyond their control, were unable to deal with them.
Fach person and site visited is listed by name in Appendix  o.   A
summary of the observations made during each visit is listed separately,
arranged in arbitrary order, A through U.

     Several general observations may be made.  First, there was often
a disturbing difference between the actual operations of a milling-
landfill facility and the potential of that facility.  Modern well-
designed plants with good equipment were available, and adequate and
sometimes over-adequate staffing was provided.  However, the  landfill
disposal of the milled refuse was often poorly planned and/or operated.
Quite often, only simple changes would be necessary to improve the site
greatly.  This lack of follow-through at most sites was disturbing,
although it aided the purposes of the study tour, because problem
sources could be documented and applied to other installations.

     A second general observation is that the concept of using milled
refuse in landfills without daily cover has developed on the basis of
operating experience and not on the basis of controlled testing.  What
is known about landfillinq milled refuse has come from a few innovative
landfill managers who have undertaken some basic evaluations on their
own initiative with virtually no financial support.  Such innovative
methods without exhaustive testing move technology forward and soon
provide experience to document advantages and disadvantages of a system.
However, it seems reasonable to expect that persons involved with the
new methods would be in close contact with others in similar situations,
especially if additional costs are associated with the new technique,
and that there would be a nenuine concern for any actual or potential
disadvantages associated with their system.  Perhaps the fact that sucn
concern v/as not widely evident attests to the acceptability of the concept
of usinn milled refuse for landfill an one of the proven methods for
solid waste disposal.
                               339

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     The third overall comment is the general  satisfaction with mi 11 inn
refuse prior to landfill as a method of handling solid waste.   Although
problems were evident at nearly every site,  and even though there was
often an apparent lack of concern or resources to optimize the operation
or to understand all of its implications, there was  v/idespread satisfaction
with the landfilling of rn'lled refuse,  'lost of the  oersons interviewed
had experience with other methods for disposing of solid wastes, includinn
land disposal, and were convinced that the use of milled refuse provided
good, nuisance-free operations on a daily basis.  Problems in  obtaining
cover soil, operating a site in wet weather, overcoming objections  by
nearby residents, conserving landfill volume,  arid obtaining permission from
various agencies for unprocessed refuse disposal sites were cited over and over
as havinn been solved with the use of milled refuse.  The people were
pleased with their operation and there was little or no thought of  changing
it, other than minor site improvements, etc.

     The final comment is the apparent lack  of true  sanitary landfills -
as defined in the theoretical United States  standard, with daily cover,
nuisance-free operation, etc - in areas visited.  As in this country,
there wore usually a few sites, cited over and over  in each country,
where a sanitary landfill is being run.  These are evidently well-knov/n
as being among the few good unprocessed refuse disposal sites.  There were
many reasons given, however, why such an ideal system would not work  at
the particular site being visited, including a lack  of available space
where unprocessed refuse could be landfilled without political problems,
a lack of cover, or objections by the public or by planninn or regulatory
authorities.  Thus, it was not unusual to hear of open dumping being  used
for the smaller disposal operations (less than 10,000 population);  milled
refuse landfilling for 10,000 to 100,000 population  operations; composting
where there is use for the compost; sanitary landfill ing for the few  large
municipalities v/ith adequate sites and cover;  and incineration for the
great majority of the population centers over 100,000 which have no
suitable disposal sites nearby.  In practice,  then,  the alternatives  to
milling seem to be open dumning for the smaller municipalities and  incin-
eration for the larger ones, except in unusual cases where a demand for compost
exists, or where the financial resources, amounts of refuse, and suitable
sites exist for sanitary landfilling.  Those sanitary landfill sites  visitod
on this tour, some of which were well-known in the area, were  comparable
to average or below-average sanitary landfill  practice in the  United  States.

     The remainder of this section provides  the results of the tour of
milled refuse landfills, arranged by subject.

Soil Cover:

     In no case was daily cover applied to milled refuse landfills, nor
did anyone think cover v.'as needed as part of normal  operations. In contrast,
all persons expressed the opinion that frequent (but not necessarily
daily) cover uas renuired to run an unprocessed refuse landfill properly.
                                340

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     'lost people stated that periodic cover would be desirable for
milled refuse landfills located close enouqh to houses for residents
to identify rejects or unnilTable objects.  It was felt that milled
refuse would appear objectionable to persons within approximately
300 feet of a site, and that frequent cover would preclude problems
of this sort.  The only reason cited for coverinn milled landfills
was an esthetic consideration, however.  All persons visited believed that
a final soil cover was necessary upon completion of a milled refuse site,
ana in for reasons of esthetics.  It was agreed that less cover was
necessary over nil led than unprocessed refuse because of the relative
ease of level inn milled refuse.

     There was some feel inn that final cover is unnecessary in remote
areas because in 3 to 5 years considerable vegetation covers milled
refuse sites and the milled refuse itself degrades to the point that
it looks much like soil, except ^or plastics and rags.  Several such
landfills '/ere viewed, ranninn in age up to in years (and in one case
to ?0 years).  Mo problems were noted due to lack of final cover, nor
were any cited by local  officials.  The presence of plastics and cloth
ninht be objectionable for some final uses, though.

Odor:

     Odor problems were observed and/or cited by local officials only
"/hen conditions were present which would normally make the site unacceptable
with burninn, as at one site where unprocessed refuse was burning undernround
in part of a milled refuse landfill.  There the milled refuse fill was
built over an open durp that had an underground fire which could not be
extinguished.  At other sites mill rejects and/or bulky items were on
fire for various reasons.  fUher cases are cited in section D on fires,
but the point is that any fire is unacceptable and will lead to odors.

     Another cause of odors was the unfortunate practice of landfill ing
dead animals, process rejects, unprocessed refuse, septic tank pumpings,
and bulky itens at milled refuse sites and not covering these materials
with either soil or milled refuse.  In the few instances where such
materials with either soil or milled refuse.  In the few instances where
such materials were promptly covered with milled refuse, no odor was
detected.  It is obvious that unplanned placement of unprocessed refuse
at a milled refus.essite destroys the integrity of the site and obviates
advantages gained by using milled refuse, unless these materials are
compacted and covered immediately.

     There were a few cases in which milled refuse was dumped into standing
water; some of the refuse was exposed to the atmosphere.  Local odors were
observed at these locations.  The ponding of surface water on milled refuse  -
another potential source of odor - was also noted, although no unusual
levels of odor could be traced to this source on the day of visit.
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     Odor levels above those at other nil led refuse sites were
detected at landfills using drum pulverizers to mill  refuse.  Two
factors are thounht to account for increased odor levels at these
sites.  First, water is normally added to  incominq refuse so the
rotating drum can more easily abrade the material.  Therefore, the
refuse is abnormally wet at tine of placement.   Second, the milled
refuse product from such pulverizers is very coarse.   For example,
in the milled product from such plants we  observed whole potatoes,
large pieces of fruit and other garbage matter, which will  rot and
produce odor just like unprocessed refuse.

     The final source of odor was poor housekeeping in the milling
plant itself, especially at the feed end.   Cases were noted where
significant amounts of incoming refuse were left in the open for
long periods, in some instances for several days.  Daily cleanup
of the plant, includinn the raw refuse storage  and handling areas,
is necessary to avoid undue odor in the plant.

     Aside from the situations discussed above, odor was not a
problem at milled refuse landfills visited, nor was odor a cause
for concern by local officials.  All stated that odor levels are
significantly below tiiose experienced in landfill ing unprocessed refuse,
even when daily cover is provided.  The odor which is present is mild
and sweetish, somethinn like silage, and is usually noticed only on the
fill itself and more particularly on active parts of the fill.  Ones
ono moves several feet away from the refuse, or onto milled refuse more
than a few weeks old, no odor is discernible.

Blowinn Debris:

     The use of milled refuse in Eurooean  landfills has not avoided
all problems of blowino debris normally associated with refuse disposal
operations.  There is no assurance that blowing will  not be experienced
just because refuse is milled.  A problem  can arise from too large a
particle size, lack of site management and planning, improper disposal
of rejects, etc.

     There was considerable evidence gathered by observation during visits,
and amplified by talks with local and regulatory authroities, to show that
milled refusn exhibits a definitely reduced tendency to blow when compared
with unprocessed refuse.  Many sites were  visited '-/here both unprocessed and
milled refuse were landfilled, and invariably the blown debris around those
sites was primarily unprocessed refuse.  On several occasions both
unprocessed refuse and millet! refuse were  being landfilled on the
day of the visit, and pictures were taken  which clearly show the
difference in the amount of blowing debris.  Blowing was observed to be
dependent on particle size.  The least blowing  debris was observed on
sites mi 11 inn refuse with a Gondard mill equipped with a 55 mm grate
opening, which resulted in trie finest grind encountered.

     Film plastics - not properly shredded by any mill observed - an I
in a few casos large pieces of paper - seemingly unaffected by certain
mills - blew to some extent.  Thus, the fences, shru.>berv,  :•
around virtually all sites visited  do collect some blow*-''
!1ote in this regard that nearly all blowing matter t!vtt !•-•  • L.
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was cainht in grass or on the lower poetions of any fencinn, trees,
or shrubs immediately adjacent to the site.

     ^ne unnecessary source of debris on many sites visited resulted
fron the met'iod of transporting milled refuse to the landfill.  I/hen
milled refuse v/as carried in open-top containers, often filled
to overflowing, over rough roads at relatively high rates of
speed, a trail of refuse v/as often strewn alonq the roadway.
Since such roadways were entirely on site, the debris was
probably not a true public nuisance, but it did lead to an
untidy operation.

Fire:

     The possibility of fire is a constant concern of resnonsible
landfill operators,  fine of the principal reasons for providing
daily soil cover in landfills of unprocessed refuse is to
partition the refuse into sections, sealing it off fron the
atnosphere to minimize fire potential.  Evidence gathered
during the study tour indicates that a properly run milled refuse
landfill still represents a fire potential, although the likelihood
of fire, and its extent if one does occur, is greatly reduced.
The most common cause of fires cited v/as vandals inniting unprocessed
refuse dumped with millfy' refuse.

     There wore two types of fires observed with milled refuse.  First,
milled refuse is capable of supporting combustion where a flame front
spreads across the surface and burns combustible material projecting
above the nac!ie/mat of the fill surface.  The seriousness of such
blazes depend on weather and compactness of the refuse.  A fire of
this tyne will not nenerally burn into the surface of the refuse mass.
It is readily extinguished with water or by using a tractor either to
scrape off the top burning layer of refuse or to cover it with milled
refuse or soil.  Surface fires appeared to occur once or twice a year
on the averaco at the sites visited.

     The second type of fire occurs when milled refuse is banked
so steeply that it is loose and relatively unconnacted.  Once
combustion takes place in this situation, it can slowly penetrate
into the bank.  If not controlled, a fire of this type can in time
spread to the entire bank, climb to the top of the landfill, and
work across the surface.

     Landfills on the study tour which had steep banks also had
an increased tendency to burn.  One site provided an unbelievable
example of how milled refuse can burn.  The site was located in
a pit perhaps 20 to 30 feet deep.  The milled refuse was piled
haphazardly around the site but concentrated around one-half of
the pit wall.  Evident!", refuse v/as trucked to the edge and
dumped; whatever annle of repose was attained was left undisturbed.
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Little if any compaction was provided.   A layer of milled refuse of
unknown denth was placed across much of the bottom of the pit, but
not leveled out.

     On the day of the visit virtually all  the fill faces on the
entire site were smoldering.  A snail pile  of several hundred pounds
of unprocessed refuse was in flames in the  center of the site, near
the mill  itself.  The plant operators indicated that the fire had been
burning for two years and that it had been  set by a highly placed
person with responsibility for the site.  Furthermore, since this
person had never asked that the fire be put out, it had been allowed
to burn freely for the entire two years, as site personnel had no
authority to extinguish it.

     What began as a day of comedy turned out to be one of the
most valuable days of the tour.  Upon closer examination, nearly
all of the fire was observed to have remained on the steep,
uncompacted slope.  There were no active flames to be seen on the
milled refuse, even on the slope.  At the bottom of the slope the
fire had burned out a snail gully, approximately a foot deep and
2 to 3 feet wide, in the milled refuse which had been spread
across the floor.  Since the gully was directly at the bottom of
the slope, there probably had been little or no compaction.
Combustion had hardly affected the bottom of the site except for
this gully.

     The burninn penetrated the slope in "fingers" perhaps a yard
long, rnakino the edge of the bank almost inaccessible.  The combustion
had worked its i/ay from the incline as much as 10 feet across the top
of the refuse and was still smoldering in some places.  In these
areas the penetration beneath the surface was perhaps an inch.

     This site substantiated what had been  observed on a smaller
scale at other sites:  nilled refuse will smolder and burn, especially
on steeply inclined faces and other places  where the refuse is loose
and uncompacted.  Mote, however, that even  after burning uncontrolled
for two years, it ''as not judged to be a major hazard or nuisance.

     Practically all fires reported at other sites began with the
burning of unprocessed refuse which had been landfilled with the
milled material and not covered.  Most of the fires were started
by vandals in bulky items which '.'ere riot milled.  Unfortunately,
bulk1' or unprocessed items wore often dumped at the bottom of on
incline of milled rcfuso, nm! fires starting in these objects were
ideally located to hurn at least the inclined face of the niilloJ
refuse,  ^thcr materials which served as a  basis for fires included
milling rejects in the case of the Tollemachc and ^ondard mills,
industrial wastes which wore not milled, and unprocessed refuse
which for some reason was landfilled along  with the milled refuse.
Reasons for the presence of unprocessed refuse included lack of
sufficient milling capacity, machinery repairs, multiple use of
a site by organizations not connected with  the mil linn facility,
arri lack of site planning and management.

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Vectors or Animal Infestation:

     Flies, rats, and birds were taken to indicate possible vector
prohl ems .

     '..'hen questions v;ere asked at each site about fly problems, the
response was normally one of surprise that the topic had been brought
up.  It seems that the fly problem is generally considered nonexistent
on milled refuse and therefore hardly v/orth discussing.  Common responses
were that some flies canbbp found on recently milled refuse, but that
virtually no flies are present on refuse older than six months.  In
either case, the ambient fly population in surrounding areas is
approximately the same as on the landfill.  It was mentioned several
times that tall grass or a freshly plowed field will result in much
greater fly populations than will milled refuse.

     Increased fly populations were observed in cases where a portion
of the refuse either was not milled, as in the case of bulky refuse,
or was adequately milled, as when whole food items were present in
the milled product.  The addition of water to refuse entering a
wet-drum pulverizer (which seemed to allow such items as whole
potatoes to pass through undamaged) undoubtedly served to boost
the fly population also.  Another likely place for flies was on
inclined faces where the refuse was highly accessible.  Fly
populations were held to a minimum where only milled refuse of
reasonably fine grind was exposed to the atmosphere and where the
refuse was shaped into smooth, even contours.  Note that even under
the worst conditions experienced, however, fly problems were
considered to be minimal and always an improvement over landfills
of unprocessed refuse, even with "daily" cover.  It should also
be noted that good daily cleanup and periodic spraying with
insecticide '..'as seen to be necessary at the feed end of the
milling facilities.

     Rodents were said to exist at several sites visited, although
only an occasional rabbit was observed during the tour.  Sites with
rats had sone unprocessed refuse, or else a rat population was present
on or near the site before milled refuse was placed.  Such sites
were topically near surface waters, had steep earth slopes, or
were near farms.  In one case, for example, there was reportedly
a mass exodus of rats from a nearby farm to the milled refuse
landfill when a change was made in the farming method; however,
soon afterwards the rats moved back to the farm, supposedly
choosing to adapt to the new farming practices rather than to
the mil led refuse landfill.
     Pxcept for two sites, there were no signs of rat activity
directly on the milled refuse.  Fven at these two sites only signs
sunn as test burrows and fecal matter were seen.  Both sites were
aliove-qrode fills which had steep and uneven sides and were
surrounded by nuch venetation.  There was also some volunteer
vegetation on the refuse near the burrows.  In one case, the
lov^r portion of the mound of refuse contained unprocessed

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material which had been covered with soil  and capned with milled
refuse.  The burrows appeared to he at or near the junction
between the milled and unprocessed refuse and went through the
cover dirt to whatever was below.  In the other case, the part
of the nound where burrows were observed had been used for the
open dumping of ballistically rejected refuse.  Not only did
this practice result in uncontrolled fire and unnecessary odors,
but it also evidently attracted a rodent population.

     Only one person, of all those interviewed, felt that rats
were eating milled refuse.  He had no proof of this possibility,
and his opinion was contradicted by many others.

     There was some confusion as to the exact species of rodents
at sites where rats were said to exist.  For example, in several
cases rabbit droppings, or large burrows capable of being used
by rabbits, were observed.  It is thought that these might have
been mistaken for signs of rat activity.  There also were several
species of animals which were locally referred to as rats, but
which did not fit the descriptions of Norway or Roof rats at all.

     Rodent problems were uniformly believed to be reduced with
milled refuse, and except for improper site management or previously
existing populations, such problems were virtually nonexistent.
Several officials did arrange for a rodent-control officer to
Inspect their sites periodically and do some routine poisoning.
This was done as a precautionary and public relations measure,
particularly in cases where a site was near a populated area or
where rodent concentrations existed prior to use of the site for
milled refuse disposal.

     In contrast to minimal rodent and insect infestation, birds
were commonly cited as being present on milled refuse landfills.
Seagulls, drawn primarily by the warmth of the refuse, are common
on milled landfills during winter, while small birds are predominant.
during warmer weather.  There was considerable division of opinion
as to whether birds obtain food from milled refuse,  'lost people
seemed to think that the large birds do not eat milled refuse,
although they '/ill pick at it.  The real debate, however, concerned
the small, seed-eatinn birds.  There is a distinct possibility
that small birds can find Mts of food in freshly milled refuse
in addition to seeds, earth worms, and crawling insects in older
milled refuse.  Several nersons said that they had observed small
birds eatinn from nillo-1 refuse, while others said that these birds
pick at the refuse but do not eat.  I'irds were commonly present
on milled refuse landfills, especially in areas where the refuse
was no more th<>n 2 to 3 days old.  The observation was made by
several people that once milled refuse is more than several days
old it loses much of its attractiveness to birds.
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     In no instance was the bird population at a site considered
a problem, but the opinion was expressed a number of times that
birds could be a potential problem at sites near airports.  It
was commonly pointed out that similar bird populations are found
in many situations, such as a freshly plowed field, and that no
complaints had been received about birds.  It was also noted
that bird populations were no higher and normally less than
those on landfills of unprocessed refuse.

Leachate and Gas:

     Very little information v/as available on leachate or gas generation.
In most instances these were not considered to be problems; hence, no
information had been gathered and no testing performed.

     Leachate seemed to be of some concern in Germany, where ground-
waters are widely used for water supply.  It is in Germany that some
of the most rinorous studies on leachate generation are taking place,
although few, if any, of these studies relate to the effect of milling
refuse on leachate generation.

     Several sites were found where ground or surface waters were under
surveillance for signs of refuse leaching.  Several wells or test wells
were being monitored for this purpose, but no effect had been noticed.
This result must be accepted cautiously, however, for some of the wells
were significant distances(up to a half mile) away from the landfill,
others were placed with no apparent knowledge of the hydrogeology of the area
so that they could be at the wrong location and/or the wrong depth,  and
still others may not have been in place long enough for leachate to
reach the well.  At one site, test wells were located immediately adjacent
to and surrounding a sizeable portion of the landfill.  i!o degradation of
ground water had been observed.

     Two sites were located in gullies or abandoned railroad cuttings
which were underdrained in such a manner that surface runoff from the
refuse or any leachate generated bytthe refuse would flow down the nully
into small streams a short distance away.  Samples of water leaving
the toe of the refuse, which was placed in about 20 foot lifts, were
analyzed by river authorities, in each case with no apparent adverse
results.  Other samples of surface water had been taken on an informal
basis at several other sites, again with no consequential results.

     Two special tests on leachate generation carried out in specially
designed facilities outside the landfill were described.  In one case,
two small boxes, one containing milled and the other unprocessed refuse,
were subjected to outdoor weather conditions.  Leachate was produced but,
because of the difference in refuse composition and quantity, the results  were
difficult to compare and translate into practical terms.  At the CAU'AG
facility in Switzerland, special leachate test bins had been constructed and
filled with milled refuse which had been composted to a low degree,  crude
refuse, and incinerator residue, respectively.  The results indicated that
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the most contaminants were produced by the milled refuse composted
to a low deqree and the least by the incinerator residue.   The
investiqator had reason to doubt the validity of the results because
of noncomparable selection of the refuse and incinerator residue,
and is currently pursuing a much larger, more controlled study.

     At the location where milled refuse from another site is to be
landfilled, a clay hern will be placed between the refuse  and the adjacent
river.  Any leachate collected by this berm or wall  will be treated
by some undisclosed means.  liote, also, that at this site  negotiations
are presently underway to set up special test beds to compare leachate
production of milled and unprocessed refuse.

     In summary, there seemed to be little concern about leachate and
qas production.  Tests which were conducted on the subject were  performed
by a few perceptive individuals who, unfortunately,  did not have the
resources to do a complete study, or by regulatory agencies who  were
monitorinn readily available water samples from surface runoff and
nearby wells.  It appears that much more data will be available  in a
few years, especially from Herman'/, '.'here the pro nnd con  schoold of
thought on millinn are Gathering evidence to support their views.
Since the purpose of the study tour was to look at ongoing refuse
milling installations, and not to provide a review of European literature on
the subject, further discussionoof the Herman studies is beyond  the
scope of this renort.

Site Design and Operation:

     There wore no obvious, uniformly applied site design  and operation
criteria in use at the sites visited.  Perhaps this  should be expected,
as a representative sample of both good and bad sites were visited.  Sone
sites were dumping in water, other were on fire.  Some sites were remote, others
were surrounded by homes.  ,H some sites only milled refuse was  landfilled,
at others crude refuse was open dumped alongside the milled refuse.

     From ttie wide variety of sites visited, there evolved some  definite
criteria which in the authors' opinion should be applied to site design
and operation.  They are:

     1.  If anything but milled refuse is to be landfilled at the site,
         it should be compacted and covered immediately;
     2.  Milled refuse should be placed and spread in a manner to provide
         smooth surfaces.  It is essential to avoid  steep inclines which
         are relatively uncompacted and present a rough surface.  Slopes
         should never exceed four feet horizontal to one foot vertical.
     3.  Daily and final soil cover is not necessary except for
         esthetic reasons.  Several persons suggested, but no
         site practiced, the routine daily covering  of milled
         refuse for sites close to (say, within 300 feet of)
         hones, schools, or other populated areas,  'lost persons
         felt that final cover was desirable for all but a few
         remote locations.


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     4.
     5.
     7.


     8.
The site should have a low fence or some other barrier
to restrict bloving debris and to keep out the public
as much as possible.
r!o refuse, whether it is milled or not, should be dumped
in bodies of surface water.
ft supply of cover dirt, or an alternative site, should
be available in case of milling equipment failure.
Diversion of runoff away from the site should be promoted
by proper contouring of the refuse and the surrounding
area.  Depressions in the refuse should be avoided.
The same site planning and engineering design used on a
conventional sanitary landfill should be applied to a
mil led refuse site.
Density and Settlement:

     The density of milled refuse in a landfill  is of special
significance and therefore will  be treated separately.  It was
somewhat disconcerting to hear repeated references to the savings
of landfill snace by using milled refuse when compared with
unprocessed refuse, yet to find  so little documentation of the
actual savings achieved,  estimates ranging from 20 to 50 percent
reduction in initial refuse volume as a result of milling were
quoted, but often the figures did not relate to  landfill  conditions.
At one site, for example, the primary reason given for milling was
to reduce the volume of refuse so higher tonnages of refuse could be
trnnsported nor barge loaded to  volumetric capacity.  Cased on
extonsivn tostinn, an increase in density of at  least GO percent
hut more probably 100 percent over the density of unprocessed
refuse was projected ly milling, where this increase would be
attained with refuse loosely packed, being compressed only by
its own weight in the barge.

     In several cases, small scale box tests were run to quantify
volume reduction through milling.  At one site,  bales were made of
milled and unprocessed refuse, similar in composition and under
identical connection.  The results were:
          Unprocessed refuse prior to baling 242
          Unprocessed refuse after baling    433
          Milled refuse after balinn         919
                                        Ibs./cu. yd
                                        Ibs./cy. yd
                                        Ibs./cu. yd
This suqoests a volume savings of over 50 percent in a landfill  if
milled rattier than unprocessed refuse is landfilled.  The densities
are lower than commonly experienced in United States landfills,  but
the significant savinns found in the test suggests that there would
be considerable savings, if not the full 50 percent, under United
States conditions.
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     At two other sites, boxes of one cubic meter were constructed and
filled with milled and unprocessed refuse.  The changing levels of
refuse in the boxes were then monitored over several  years.  The
results showed that milled refuse was more dense than unprocessed
and that the volume occupied by the milled refuse dropped steadily
with time.  It is difficult to use these findings in landfill
desiqn, however, because refuse composition and moisture content
were not determined and, in one case, unequal  and unknown weights
of refuse were placed in the milled and unprocessed refuse boxes.
Furthermore, since no compaction was applied,  the results do not
reflect what happens in a landfill but more properly relate to the
density during trans nort to the site.

     Perhaps the best landfill test results at a site were obtained
when refuse was dun from the landfill and weighed.  The in-place
volume was estimated by backfill inn the hole with a known volume
of sugar sand.  Such a test is subject to certain problems and errors,
but the results did indicate approximately a 30 percent increase
in density hy usinq milled refuse in landfills.

     All persons agreed that milling of refuse would result in a
savings of landfill space.  Theddiscrepancy was not whether such
a savinqs existed but what actual change in density could be expected.
flote in this regard that much smaller equipment than that used in
United States landfills was observed in most European installations.
It is felt that the difference in landfill density between milled and
unprocessed refuse would be greater when lighter machines are used for
compaction, so one nust bo careful in transferring data on density
generated elsewhere to the United States.

     Settlement of milled refuse v/as invariably described as uniform,
providing unprocessed materials such as bulky  items were well compacted
or were not present in the fill.  This observation was borne out by
site inspections where, except in obvious cases of poor initial
levelinq at some sites, older sites were seen  to retain a uniform and
even surface.  Although all persons interviewed stated that milled
refuse settled more uniformly than unprocessed refuse, this comparison
could not bo confirmed by visits to tiie sites  on this particular itinerary.

     Little information -./as available on the other aspect of
settlement:  namely, the total amount of settling to lie expected
v;itfi milled as opposed to unprocessed refuse,  and the relative
rates of settling.  Several persons felt that  settlement would
be 3 to 4 times faster with milled refuse, where a milled refuse
landfill will be nearly completely settled five years after placement
in comparison to 15 to 20 years for unprocessed refuse to reach the
same degree of stability.  Of course, the actual figures would vary
widely depending en many factors, but most of  the persons citing
these or similar figures gathered them as a result of years of
experience.  Thus, although tha actual figures may vary, and even
thounh most of the persons interviewed had no  data to back up their
remarks, it was commonly asserted that milled  refuse landfill will
beco"e stable vn'th respect to settlement in less tin0 t i   'ill
unprocessed refuse.
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     l.'hat little that was known about total settlinq of milled refuse
scened to come fron tiie small boxes cited earlier in the discussion
on refuse density,  because of 'iron!ens translatinn the results to
an actual landfill, however, these results are difficult to apply
accurately to the question nf ultimate settlement and will not be
discussed further.

     A final "iajor consideration in site design is whether the
milled refuse landfill should be constructed in uncompacted layers
no nore than three feet thick which are allowed to stabilize for
3 to 6 months before the next layer is applied, or whether much
thicker compacted lifts should he used.  In the latter case, the
refuse will  take longer to decompose and will undergo somewhat
uniform degradation.  In the former case, the fill is virtually
stabilized as it is constructed, because more rapid decomposition
occurs close to the refuse surface.  Mother way of accomplishing
tin's same goal is to allow milled refuse to compost in windrows
prior to landfill inn.  Hepending on which of these two methods, or
some modification of them, is chosen, the design of a site would be
quite different.  For example, if the choice is to decompose refuse
quickly in thin layers, the refuse should be dumped as loosely as
possible and no compaction should be provided.  All traffic should
be diverted around the area until the refuse is stabilized and
ready to accept the next layer.  At this point the refuse should
be compacted and traffic run over it as much as possible to achieve
the highest possible density.

     The authors are not prepared to make any recommendations as to
which method is better.  There are believers in both alternatives,
and sites are being operated at both extremes and at many levels
in between.   It seems useful to point out that there are various ways
of operating a milled refuse landfill and that this is one area that
deserves much study.

Public Acceptance:

     Along with savings in landfill volume, increased public
acceptance was typically given as a major reason why refuse was
being milled at the various sites visited.  The fact that the
public was more willing to accept a milled than unprocessed refuse
landfill was never disputed throughout the tour.  It appears, however,
that public opinion was usually based more on emotion than on evidence
which convinced them that milled refuse would be less obnoxious than
unprocessed refuse.  In the United Kingdom, for example, the public seo^is
to consider incinerator residue and willed refuse together under the
term "treated refuse", and of course, treated refuse has to be better
than untreated refuse.
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     The presentation of Q fictitious but reasonable example in the
Unite'! States v/ill serve to illustrate the point.  Suppose that a
nev/ site is needed for refuse disposal for a ponulation of insufficient
size to support an incinerator and that land disposal is the only viable
method available.  After a site has been secured, application is made
to the Planning Authority, which has virtually complete control of
refuse disposal, both from a standpoint of planning and of regulation.
If local opposition to the proposed site arises prior to required public
hearings, the concept of using "treated", or in this case milled, refuse
can be introduced as a compromise.  The application may then be approved
subject to the requirement that mostly milled refuse, or perhaps only
milled refuse, be landfilled at that site.  Several sites were visited where
milled refuse '..'as offered as a compromise to obtain a site.

     ^f interest to this report is v/hether permission to use a site
with milled refuse is based on sound technical advice and/or adequate
exnerience.  The decision makers do have a technical staff, and they
can call on experts from around the country as well as from federal
and other levels of government; however, the fact remains that the
decision makers are elected and are generally not experts in matters
related to solid wastes.  They may or may not use the technical advice
provided to them.  Although there v/as some conflict of opinion between
persons interviewed, there have been cases in nhich the Planning
Authority did base its decision on the merits of landfilling milled
refuse as opposed to unprocessed refuse.  The fact that landfilling
of milled refuse is gaining popularity and is nov considered one of
the ordinary methods of solid waste disposal - along with sanitary
landfill, composting, and incineration - attests to the acceptance
of the milled refuse concept by the public and, in turn, by planning
authorities.

     Finally, a question asked of every person interviewed was
whether he knew of complaints registered by the public against
landfills with milled refuse.  In nearly all cases the response
was no.  In each instance where complaints had been received, they
were easily traced to improper operation, as discussed earlier in
the report, or to special site considerations not related to the
use of milled refuse.  Thus, local officials were pleased with the
public acceptance of their operation and were in no case contemn!atim
returninn to the landfillinn of unprocessed refuse.

Refuse Composition:

     The only analyses found for refuse composition were European
or national averages as quoted in texts, national surveys, and the
like.  '!o firm res v/ore obtained for any of the specific sites visited.
                                352

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     Information on the fraction of the refuse coming from residential,
commercial, and industrial sources v/as generally available but too
variable to I e of interest iiere.  Hhile some sites had nore or less
corrugated than others, for instance, the refuse going into nil! ing
facilities appeared on the whole to be quite similar to refuse in the
United States.  It is unlikely that milled refuse will behave differently
in the United States due to changes in the refuse composition alone.

     A moro sinnificant difference is the larqor amount of bulk
material in U.S. refuse than in European solid waste.  /"I though it
is difficult to quantify the difference, there did apnear to be
fever bulky items as w^ll as loss construction and demolition deuris
and lawn, tree, or shrub clippings at the European sites.  Thus, a
hinher fraction of the refuse produced in Europe would seen to be
"n'llr'Me than in the United States.

     "atprial  not Milled at the sites visited was either sent to
another landfill, often an open dumn, or was disposed at the Milled
refuse sitp.  'luch has already been \;ritten about the hazards of the
latter pr-icticG, so it '-'ill not be repeated here.  " pronounced
tendency toward the use of larger mills canable of hand! in'"! a larger
portion of the solid waste was noted.  r'll of the major mill
nanur'>cturers seened tn have, or i/ere planning to produce, larner
;n'lls canal. lr> of ta!;inn more bulky material, whits goods, furniture,
an>i the like.
       tour of European refuse nil! inn installations was made to
           nd thr.-n relate to the United States, European experience
in this metiod of handling solic' wastes.  Of particular interest i.'as
the landfillim of milled refuse without daily cover, ^ practice "lii
has been in use up to 20 years in Europe.

     Site visits to nil led refuse landfills and discussions with
knowledgeable person? focused on such matters as soil cover, odors,
Mowinn debris, fire, vectors, leachate, gas, site design, density,
            ^ublic acceptance, and refuse composition.
     It wis concluded that milling refuse for disposal in a landfill
did not curp all pro'.! lens associated "ith land disposal of refuse.
Mo1 /over, the Tactic? is widely used anc.' is accented bv "Jnim'strators ,
refill '~»tory nnoncios , and the nublic as an improve:! method of landfill ing
           not require daib' cover, except nerhans for aesthetic nurnoses
                               353

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                          ACKNOl-JLEPnEMEMTS

     The support of the University-Industry Research Program of the
Graduate School at the University of Wisconsin and the flational Center
for Resource Recovery is nrntefully acknowledged.  Special thanks are
due to the many people in Europe who qraciously qave of their time,
frequently after normal worldnn hours, to meet with us, provide
transportation, make appointments, etc., and to those who have
reviewed tin's report.  Complete copies of this report are available
from:

                 The National Center For Resource Recovery
                 1211 Connecticut Avenue, N.W.
                 Washinnton, D.C.  20036
                                354

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                         X, APPENDICES

A - Gondard Cost Calculations

      The basic method used to make the cost calculations was to
divide the annual cost for such items as labor, depreciation, and
power by the projected annual tonnage milled. The annual projected
tonnage was determined from the average work rate of the machine,
the number of hours per day that the machine is operated, and an
assumed 48 work weeks/year.  It is assumed that the plant will
be inoperative 4 weeks per year, 1-1/2 weeks due to legal holi-
days and 2-1/2 weeks due to down  time for major repairs and maintenance,
It is felt that computing costs on an annual basis is more reliable
than any other method, such as per month.  For example, labor
costs, determined monthly, for a particular grate size may be penalized
if a man was sick or on vacation, which is unrelated to the size
of grate being used in the machine.

      The only exception to the computation of costs on an annual
basis was for the power cost. Since the grates in the mill were
changed periodically in an effort to determine the optimum size,
a particular set of grates was not in the mill for the same period
as the billing from the power company.  It was thus necessary to
proportion the power consumption and tonnage milled during the
experimental periods to one month,  since utility bills  are based
on monthly consumption. The resultant utility cost was then divided
by the monthly  tonnage milled.  It was not necessary to make this
type of projection for other utilities since they are not dependent
upon the grate size or tonnage milled by the machine.

      A description is given below of the pertinent factors concern-
ing each of the  cost categories listed in the body of the report.


LABOR

      The average annual labor rate for the plant operator,  assistant
plant operator, and maintenance man is $7.20 + $6.50  + $5.45/hour,
or $19.15/hour. $19.15/hour x 2,080 hours/year = $39,830/year
labor cost.  Annual average labor wage rates  are calculated in Ap-
pendix D and include all fringe benefits plus overtime. It is significant
to note that inclusion of fringe benefits amounts to an hourly wage
rate 30 percent higher than the basic wage rate.  Inclusion of overtime
with the fringe  benefits results in a wage rate which is 50 percent
greater than basic wage rate. The labor cost per ton  on an average
annual basis is then determined by dividing $39,830 by the projected
annual tonnage.
                              355

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AMORTIZATION

      The annual cost was determined by assuming a reasonable
machinery life and interest rates depending upon the source of
funds. The annual cost was divided by the projected annual ton-
nage milled.  Land costs are excluded from the amortization costs.
The following table lists the amortization data used to arrive at
the annual amortization cost of $32,100 per year.
                          TABLE A-l

                       Depreciation Data
              Original   Estimated   Interest   Salvage   Annual
 Cost Item _ Cost    Life-Years    Rate _ Value _ Cost

 Building     $133,100      20          5.8     $4,000    $11,300

 Grinder and
   Conveyors   126,700      15          5.8      4,000     12,700

 Scale           6,900      20          7.0      1,000        600

 Front End
  Loader        15,400       8          7.0      3,000      2,300
  Trucks  (2)    38,000     10          7.0      3,000      5,200
              Total Annual Cost - Amortization           $32,100
POWER COST

      As explained earlier, the experimental periods did not exactly
coincide with the utility companies' billing periods.  It was therefore
necessary to project power consumption to a monthly basis in order
to determine the equivalent monthly costs.  This is so because power
rate charges decrease with increasing usage. The following table
lists the proportionate monthly costs and tonnage milled during
the experimental runs.  The costs of power ranging  from $.34 to
$. 30 per ton are the weighted averages during the times that the
three grate sizes were used.
                              356

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                         TABLE A-2




       "Actual" Power Costs for Feed Conveyors and Mill
Grate Size
(Inches)
3-1/2



4
5





6-1/4





Time Period
Sept. 18-Oct. 8, 1967
Jan. 1-Feb. 1, 1968
March 18-31 , 1968
April 1-21, 1968
July^l-28, 1968
Weighted Average
May 14- June 2, 1968
June 3-30, 1968*
Sept. 16-20, 1968
Sept. 30-Nov. 3, 1968
Nov. 4-Dec. 1, 1968
Dec. 2-29, 1968
Weighted Average
Oct. 30-Nov. 19, 1967
Dec. 11-31, 1967
Feb. 2-March 17, 1968
April 22-May 13, 1968
July 29-Aug. 18, 1969
Aug. 19-Sept. 15, 1968
Weighted Average
Proportioned
Cost
$ 295
298
318
316
312
$1,539
326
318
301
298
294
283
$1,820
293
280
277
305
298
296
$1,749
Monthly
Tons
828
744
930
956
984
4,442
1,224
1,187
967
949
930
773
6,030
1,012
735
780
1,116
1,131
1,060
5,834
Cost
Per Ton
$0.36
0.40
0.34
0.33
0.32
$0.34
0.26
0.27
0.31
0.31
0.32
0.36
$0.30"
0.29
0.38
0.36
0.27
0.26
0.28
$0.30
* Excluding week of June 17-21 when private contractor loads were milled.
                              357

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OTHER UTILITIES

      It was not necessary to project the consumption of other utilities
from the experimental period to one month because the water,  lighting
and gas heating costs were independent of the grate size used in
the machine and the tonnage milled.  Since these projections to monthly
quantities were not needed,  it is possible to total the utility bills
on a  calendar year basis and divide by the annual tonnage to arrive
at the cost per ton.  The lighting, water and gas heating costs for
calendar year 1968 were totalled and  the annual cost of $2,300, $200
and $1,200 is listed in the cost data section of the body of the report.
HAMMER WEAR

      A more extensive report of the hammer wear costs and main-
tenance programs is contained in Appendix E.  During most of the
project, the life of a set of hammers was near 400 to 500 tons per
set.  Towards the end of the project, it was shown that daily resurfacing
of the hammers could prolong the life of a set to 1,200 tons.  It is
based on the recent work that the lives and costs of hammer maintenance
are estimated in Appendix E. Contrary to popular opinion, it should
be noted that the magnitude of costs  associated with hammer wear
is relatively small compared to labor and  amortization.  The labor
costs associated with hammer wear and maintenance is excluded
from the hammer wear costs and is included with the labor costs.
MILL MAINTENANCE

      Other maintenance costs for the mill besides hammers include
the cost of:  replacing grates;  replacing wearable mill parts such
as replaceable liners , shafts and spacers;  and using oxygen and
acetylene for cutting purposes. The major cost is for the replace-
ment of grates, which is estimated to be necessary every 8,000 tons.
These costs will probably fluctuate very little as indicated in the
table of cost data in the body of the report.
SMALL EQUIPMENT

      A detailed accounting of small equipment purchased during
the last project year shows the total cost of such equipment to be
                              358

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$800. This equipment includes such items as tools, a bench grinder,
a vacuum cleaner, rubber belting and installation of a flame deflector.
It is to be noted that purchases of this type are continuing in the
third year of the project, and should  not be written off as initial
expenses.
GENERAL SUPPLIES

      A detailed accounting of the general supplies during the last
project year likewise indicates a total expenditure of $1,100.  This
expense is comprised of many small items including janitorial sup-
plies and general supplies such as  oil and small hardware expenses
FRONT END LOADER OPERATION

      The $500 listed in the table for the front end loader operation
is the billing  from the City of Madison Garage for maintenance done
on the front end loader during one year.  Note that the depreciation
was previously included under the amortization cost.
OTHER COSTS

      An accounting of the project expenses also reveals $1,700
of other miscellaneous-type expenses during the third project year.
Included in these costs are items such as sheet metal, conveyor
wiring, a chain for the speed reducer on the conveying equipment,
repair of the scale, installation of new bearings, and seal coating
the parking area.
ADJUSTED COSTS

      There is a second table of costs in the body of the report
which reflects what the cost of the present pilot plan operation might
be if adequate hauling equipment could be found for the milled refuse.
It is assumed the plant could be operated by two men, and the work
scheduled so the plant was milling refuse 7 hours per day instead
of the current 5.33 hours per day.  In the table of adjusted costs
per ton, the projected annual tonnage is higher than the tonnage
figures in the preceding table because the plant is in operation for
more hours per day. The other major change in the table of
                               359

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adjusted costs is that the labor cost is $28,000 instead of $39,830
because one man (the lowest paid) is no longer required at the plant.
Other minor changes are that the power, hammer wear, mill main-
tenance , and front end loader operation costs will increase above
the actual situation due to the additional tonnage being milled.
TRANSPORTATION COSTS

      Costs are also listed later in the body of the report for hauling
of refuse from the plant to the landfill.  These operating costs are
described as transportation costs and so are considered independently
of the plant operating costs. An accounting of the billing from the
City of Madison Garage reveals the expenses listed in Section III-
A, Tables  3   and  4
                                360

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§-~ Gondard Projected Annual Tonnage

      In order to compute costs per ton on the basis of annual cost
and annual tonnage, it is necessary to project the annual tonnage
that could be pulverized if one grate were used continuously in
the mill for one year.  Computation of cost per ton on an annual
basis is felt to be much more reliable than computing on a shorter
basis such as per month. Use of a short time period may not accurately
indicate the effects of vacations and major repairs during which
time the plant may be shut down.

      The projected annual tonnage is based on the most current
production capability of the machine, the number of hours per day
that the machine is operated (based on previous experience) ,  and
on an estimated number of working weeks per year. Since rubber
cleats were placed on the conveyors feeding refuse to the mill, it
has been found that the production rate has increased. More recent
experience has verified that it is reasonable to assume the overall
production rates with the 3-1/2 inch grate will be 8.4 tons per hour;
and will be 9 .0 tons per hour with the 5-inch grate; and will be
9.4 tons per hour with the 6-1/4 inch grate.  The overall production
rate is  used because it includes down time due to conveyor jams
of the mill. Thus, use of the overall production rate with the actual
hours that the machine is milling refuse should reflect accurately
the tonnage that can be milled in one year when one size grate is
used continuously.

      Eight months of detailed scrutiny of the operating records
of the plant revealed that the machine is actually milling refuse
for 5.33 hours per 8-hour working day. The remainder of the time
is spent on clean-up, getting  ready for the day's operation, shut
down for necessary repair of trucks, lunch, and lapse between
arrival of first load of refuse and start of milling operations.

      Since the plant operates 5 days per week, the only other figure
needed to project annual tonnage is the number of weeks the plant
is in operation per year.  City of Madison employees receive 7 .5
days of legal holidays per year which is the same as 1-1/2 weeks.
It is further assumed that the plant will be shut down for major re-
pairs and alterations for an additional 2-1/2 weeks per year.  Although
the pilot plant has been shut down more frequently than 2-1/2 weeks
per year,  it is felt that correct initial design and scheduling of
                               361

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maintenance could reduce the down time to 2-1/2 weeks per year.
Thus, the 2-1/2 weeks for shutdown for major repair plus 1-1/2
weeks' vacation amounts to 4 weeks per year that the plant is not
in operation .

      The projected annual tonnage for the three grate sizes is
then:

3-1/2 Inch Grate -

      8.4 tons  x 5.33 hrs  x  5 days x  48 wks  =  10,750 tons/year
       hour        day        week     year
5-Inch Grate -

      9.0 tons  x 5.33 x  5 x  48  = 11 ,500 tons/year
       hour
6-1/4 Inch Grate -

      9.4 tons  x 5.33 x 5 x  48  = 12,050 tons/year
       hour
                               362

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C - Summary Data From Gondard Experimental Runs
     The following sheets summarize the data obtained during each of
the Gondard experimental runs.  Data were kept each day of plant
operations on the quantities of refuse received at the landfill, the
portion milled, and the portion bypassed around the plant.  The daily
operating records also indicate the time that the plant was operating,
the minute the plant was shut down, the length of shutdown, and the
reason for shutdown, such as refuse truck being full.  In addition,
daily records were kept of work times in the plant, the compaction
equipment operator's time in the landfill, cover dirt usage and utility
consumption.  It is this daily information that is summarized on the
sheets contained in this appendix.
                                   363

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                TABLE C.  Summaries of Experimental Runs.

                      SUMMARY OF EXPERIMENTAL RUN
          MILLED COMBINED REFUSE - 3-1/2-IN. GRATES - FALL 1967
                     September 18 - October 6, 1967
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Milled
        Rejected
        Total
                              534
                               77.9 hours
                               11.4 hours
                               89.3 hours
                        Tons per Hour
 Rate
                                                     6.6
                                                     0.2
                                                     6.8
Overall
 Rate
 5.8
 0.2
 6.0
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately) 257 Loads - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled
Work Times
     Man-Hours of Milling - 77.9 hours x 3 men     »
     Total Man-Hours 1n Plant
     Man-Hours of Compaction (1 man)
     ManMilled - Man-Hours
        Unprocessed - Man-Hours
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                 Hours
                 (Hours) per Hundred Tons
                 Hours
Cover Dirt - Cubic Yards
Equipment Time - (Hours) per Hundred Tons
Cover Dirt - Yards per Ton
Utility and Equipment Usage
     220 Volt Electrical Service
     440 Volt Electrical Service
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
                           Kilowatt Hours
                           Kilowatt Hours
                                                                1,167
                                                                  534
                                                                  633
                                                                  122
                                                                  346
                                                                  157
                                                                   45%
                                                     234 man-hours
                                                     378

                                                      18.4
                                                      33.0
                                                     133.5
  534
   18.4
    3.4

  633
   33.0
1,190
    5.2
    1.9
6,060
8,160
  135
3,775
  241
   10.2
                                    364

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                             TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
            MILLED COMBINED REFUSE - 2-IN. GRATES - FALL 1967
                           October 9-27, 1967
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production
        Milled
        Rejected
        Total
                                 450
                                  75.1 hours
                                   7.9 hours
                                  83.0 hours
                   Rates - Tons per Hour
                       Operating
                         Rate
                          57?
                          0.4
                          5.0
          Overall
           Rate
          "571
           0.3
           5.4
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately) 257 Loads - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled
Work Times
     Man-Hours of Milling - 77.9 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction (1 man)
        Milled - Man-Hours
        Unprocessed - Man-Hours
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                    Hours
                    (Hours) per Hundred Tons
                    Hours
   Cover Dirt - Cubic Yards
   Equipment Time - (Hours) per Hundred Tons
   Cover Dirt - Yards per Ton
Utility and Equipment Usage
ty_
m
     220 Volt Electrical Service
     440 Volt Electrical Service
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
     Packer No. 411 - Miles
Kilowatt Hours
Kilowatt Hours
                                                                   1,073
                                                                     450
                                                                     623
                                                                      72
                                                                     363
                                                                     129
                                                                      36%
                                                          225.3 man-hours
                                                          399.5

                                                           20.7
                                                           35.9
                                                          124.0
                            450
                             20.7
                              4.6

                            623
                             35.9
                          1,180 for 402 tons
                              5.8
                              2.9
4,520
8,480
1,106
4,235
   93
    8.4
   15
                                    365

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                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
          MILLED COMBINED REFUSE - 6-1/4 IN. GRATES - FALL 1967
                     October 30 - November 17, 1967
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Milled
        Rejected
        Total
                                  703
                                   75.7  hours
                                    7.6  hours
                                   83.8  hours
                            Tons  per Hour
                       Operating
                         Rate
                          9T1
                          0.2
                          9.3
          Overall
           Rate
         ~~O
           0.2
           8.4
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately) 257 Loads - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled
Work Times
     Man-Hours of Milling - 78.7 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction (1 man)
        Milled - Man-Hours
        Unprocessed - Man-Hours
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                     Hours
                     (Hours)  per  Hundred  Tons
                     Hours
    Cover Dirt -  Cubic  Yards
    Equipment  Time  -  (Hours)  per  Hundred  Tons
    Cover Dirt -  Yards  per  Ton
Utility and Equipment Usage
jy_
 220  Volt Electrical
 440  Volt Electrical
                         Service
                         Service
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
Kilowatt Hours
Kilowatt Hours
                                                                    1,165
                                                                      703
                                                                      462
                                                                       82
                                                                      375
                                                                      195
                                                                       52%
                                                           227.1  man-hours
                                                           399.5

                                                            29.6
                                                            35.5
                                                           131.5
                            703
                             29.6
                              4.2

                            462
                             35.5
                          1,030 for 683.20 tons
                              7.7
                              1.5
5,500
7,680
2,011
4,000
  111
   10.2
                                   366

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                            TABLE C  (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
         MILLED GARBAGE - 6-1/4-IN. GRATE - EARLY WINTER 1967-68
                     November 20 - December 1, 1967
Plant Performance
     Tons Milled                      103
     Milling Time                       6*9 hours
     Down Time                          2.6 hours
     Total Time                         9.5 hours         Operating    Overall
     Average Production Rates - Tons per Hour               Rate        Rate
        Milled                                              14.910.8
        Rejected
        Total                                               14.9        10.8

Refuse Quantities
     Total Milled - Tons                                                  103
     Total No. of Loads Milled                                             40

Work Times
     Man-Hours of Milling - 3 meat* 9.5 hours                   28.5 man-hours
     Total Man-Hours in Plant (including 119.7
      man-hours spent milling 311 tons of rubbish)             402   man-hours
     Man-Hours of Compaction (1 man)
        Milled - Man-Hours
        Unprocessed - Man-Hours
     Total Man-Hours for Compaction Equipment Operator

Landfill
~~   MTTled
        Tons                                                    89
        Equipment Time - Hours
        Equipment Time - (Hours) per Hundred Tons
     Unprocessed
        Tons                                                    44
        Equipment Time - Hours
        Cover Dirt - Cubic Yards                                90
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton                               2.0

Utility and Equipment Usage (For 3 weeks of milling 311 tons
 of rubbish and 103 tons of garbage)
     220 Volt Electrical Service - Kilowatt Hours            5,260
     440 Volt Electrical Service - Kilowatt Hours            5,600
     Gas - Hundred of Cubic Feet                               232.8
     Water - Cubic Feet                                      2,976
     Load Lugger - Miles                                       127
     Frond End Loader - Hours                                    8.7
                                    367

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                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
       MILLED SEPARATED RUBBISH - 6-1/4 IN. GRATE - WINTER 1967-68
                     November 27 - December 8, 1967
PIant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
                                      311
                                       38.
                                        1,
hours
hours
                                       39.9 hours
     Average Production Rates - Tons per Hour
        Milled
        Rejected
        Total
              Operating
                Rate
                 779
                 0.2
                 8.1
Refuse Quantities
     Total Milled
     Total No. of

Work Times
                  - Tons
                  Loads Milled
     Man-Hours of Milling - 3 men x 3919 hours
     Total Man-Hours in Plant (including 28.5 man-hours
      spent milling 103 tons of garbage
     Man-Hours of Compaction
        Milled - Man-Hours
        Unprocessed - Man-Hours
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                         Hours (7.3 man-hours)
                         (Hours) per Hundred Tons
 Overall
  Rate
"776
  0.2
  7.8
                            311
                             91
                                                               119.8 man-hours

                                                               402

                                                                 9.2

                                                               127
                   311
                   264 tons
                     2.8
                         Hours
        Cover Dirt - Cubic Yards
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton

Utility and Equipment Usage (For 3 wefcks on milling 311 tons of
 rubbish and 103 tons of garbage)
     220 Volt Electrical Service - Kilowatt Hours
     440 Volt Electrical Service - Kilowatt Hours
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
                                                             5,
                                                             5,
                   260
                   600
                   232.8
                   976
                   127
                     8.7
                                    368

-------
                            TABLE C  (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
          MILLED COMBINED REFUSE - 6-1/4 IN. GRATE - WINTER 1967-68
                          December 11-29, 1967
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Milled
        Rejected
        Total
             474
              70.0 hours
               1.8 hours
              71.8 hours
       Tons per Hour
Operating
  Rate
   577
   0.1
   6.8
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately)  H Loads
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled
Work Times
     Man-Hours of Milling - 3 men x 72.8 hours
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled - Man-Hours
        Unprocessed - Man-Hours
     Total Man-Hours for Compaction Equipment Operator
Landfill
     MiTled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time - Hours
Hours
(Hours) per Hundred Tons
        Cover Dirt - Cubic Yards
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton
Uti1i ty and Equipment Usage
     220 Volt Electrical Service
     440 Volt Electrical Service
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
          Kilowatt Hours
          Kilowatt Hours
 Overall
  Rate
~63
  0.1
  6.6
                                                975
                                                474
                                                501
                                                 27
                                                374
                                                152
                                                 40%
                                      218.4 man-hours
                                      381   man-hours

                                       16.4

                                      127
     474
      17.1
       3.6
   5.280
   5,600
     165
   3,053
     113
       7.2
                                   369

-------
                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
        MILLED COMBINED REFUSE - 3-1/2-IN. GRATE - WINTER 1967-68
                      January 2 - February 1, 1968
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates -
        Milled
        Rejected
        Total
                              689
                               98.6 hours
                                2.7 hours
                              101.3 hours
                        Tons per Hour
Operating
  Rate
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately)
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 3 men x 98.6 hours
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Overall
 Rate
                                                     0.2        0.2
                                                     7.0        6.8
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                 Hours
                 (Hours) per Hundred Tons
                 Hours
Cover Dirt - Cubic Yards
Equipment Time - (Hours) per Hundred Tons
Cover Dirt - Yards per Ton (Cubic)
Utility and Equipment Usage
     220 Volt Electrical Serv1ce
     440 Volt Electrical Service
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
                           Kilowatt Hours
                           Kilowatt Hours
                                                              1,496
                                                                689
                                                                807
                                                                 64
                                                                540
                                                                223
                                                                 40%
                                                       296 man-hours
                                                       686
                                                       206
                                                        27
                                                        56
     689
      27
       3.9

     504 (as of Feb. 1)
      56
     450 (incomplete)
      11.1
       0.9 (incomplete)
   8,820
  10,080
     389.1
   4,439
     129
      30.9
                                    370

-------
                            TABLE C  (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
        MILLED COMBINED REFUSE - 6-1/4 IN. GRATE - WINTER 1967-68
                      February 2 - March 15, 1968
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Milled
        Rejected
        Total
             830
             108.4 hours
               6.5 hours
             114.9 hours
       Tons per Hour
Operating
  Rate
                                    0.1
                                    7.7
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately) - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 108 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
    "MiTled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time - Hours
Hours
(Hours) per Hundred Tons
        Cover Dirt - Cubic Yards
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton
Utility and Equipment Usage
     220 Volt Electrical Service -
     440 Volt Electrical Service -
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
          Kilowatt Hours
          Kilowatt Hours
                                      324
                                      818

                                       32
                                      121
                                      278
     844
      31.8
       3.8

   1,456
     177.1
   2,880
      12.2
       2.0
  14,620
   8,800
     393.1
   6,512
     158
      46
 Overall
  Rate
"771
  0.1
  7.2
                                             1,795
                                               830
                                               565
                                                45
                                               746
                                               283
                                                38%
                                   371

-------
                            TABLE C  (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
     MILLED COMBINED REFUSE - 3-1/2-IN. GRATE - LATE WINTER 1967-68
                            March 18-29, 1968
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Total
                                 343
                                  48.3 hours
                                   1.3 hours
                                  49.6 hours
                           Tons per Hour
                       Operating
                         Rate
           Overa!1
	     Rate
 7.1         6.9
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately) - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 48 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                    Hours
                    (Hours) per Hundred Tons
                    Hours
   Cover Dirt - Cubic Yards
   Equipment Time - (Hours) per Hundred Tons
   Cover Dirt - Yards per Ton
Utility and Equipment Usage
cy a
220 Volt Electrical
440 Volt Electrical
                         >ervice
                         Service
     Gas - Hundred of Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
Kilowatt Hours
Kilowatt Hours
                                                                   705
                                                                   343
                                                                   362
                                                                    25
                                                                   263
                                                                    97
                                                                    37%
                                                          144
                                                          270

                                                          no record kept
                                                          no record kept
                                                           84
                            319
                            no record kept
                            not available

                            197
                            no record kept
                            580
                            not available
                              2.9
 4,380
 4,960
    60.5
 2,924
    27
    15.0
                                   372

-------
                            IABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
         MILLED COMBINED REFUSE - 3-1/2 IN. GRATE - SPRING 1968
                            April 1968


Plant Performance
     Tons Milled                      617
     Milling Time                      87.2 hours
     Down Time                          2.2 hours
     Total Time                        89.4 hours         Operating    Overall
     Average Production Rates - Tons per Hour               Rate        Rate
        Total                                                7716.9

Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons          1,231
     Total Milled - Tons                                                617
     Total Unprocessed - Tons                                           614
     Total Large Items & Brush (considered separately)                   38
     Total No. of Loads of Refuse Received at Site                      440
     Total No. of Loads Milled                                          129
     Percentage of Total Loads which are Milled                          30%

Work Times
     Man-Hours of Milling - 87 hours x 3 men                   261
     Total Man-Hours in Plant                                  395
     Man-Hours of Compaction
        Milled                                                  22
        Unprocessed                                             63
     Total Man-Hours for Compaction Equipment Operator         127

Landfill
     MlTled
        Tons                                                   617
        Equipment Time - Hours                                  22.3
        Equipment Time - (Hours) per Hundred Tons                3.6
     Unnrocessed
        Tons                                                   614
        Equipment Time - Hours                                  62.7
        Cover Dirt - Cubic Yards                               cell not complete
        Equipment Time - (Hours) per Hundred Tons               10.2
        Cover Dirt - Yards per Ton                             cell not complete

Utility and Equipment Usage
     220 Volt Electrical Service - Kilowatt Hours            7,800
     440 Volt Electrical Service - Kilowatt Hours            8,480
     Gas - Cubic Feet                                       13,700
     Water - Cubic Feet                                      3,154
     Load Lugger - Miles                                        65
     Frond End Loader - Hours                                   14.3
                                    373

-------
                            TABLE C (Cont.)


                      SUMMARY OF EXPERIMENTAL RUN
         MILLED COMBINED REFUSE - 6-1/4 IN.  GRATE - SPRING 1968
                        April 22 - May 13, 1968
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates -
        Total
                                 775
                                  95.5 hours
                                   2.3 hours
                                  97.8 hours
                           Tons per Hour
                       Operating
                         Rate
                                                        8TT
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 94 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time - Hours
        Equipment Time - (Hours) per Hundred Tons
     Unprocessed (April 1 - May 13, 1968)
        Tons
        Equipment Time - Hours
        Cover Dirt - Cubic Yards
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton
Utility and Equipment Usage
ilL
220
440
         Volt Electrical Service
         Volt Electrical Service
     Gas - Cubic Feet
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
Kilowatt Hours
Kilowatt Hours
                                                          282
                                                          484

                                                           25
                                                           31
                                                          134
           Overall
            Rate
            7.9
                                                                 1,384
                                                                    775
                                                                    609
                                                                    448
                                                                    229
                                                                    50%
                                                          739
                                                           25
                                                            3.4

                                                          939
                                                           94
                                                        cell not complete
                                                           10.0
                                                        cell not complete
 6,940
 8,160
14,600
 3,446
    50
     5.9
                                    374

-------
                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
           MILLED COMBINED REFUSE - 5-IN. GRATE - SPRING 1968
                             May 14-31, 1968
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production
        Total
                                 733
                                  88.8 hours
                                   5.1 hours
                                  93.9 hours
                   Rates - Tons per Hour
                                                          Operating
                                                            Rate
                                                             8.2
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total Large Items & Brush (considered separately)
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 89 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
RTTled
   Tons
   Equipment Time
   Equipment Time
Unprocessed
   Tons
   Equipment Time
                         Hours
                         (Hours) per Hundred Tons
                         Hours
        Cover Dirt - Cubic Yards
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton
Utility and Equipment Usage
      y
      2
220 Volt Electrical Service
440 Volt Electrical Service
Gas - Cubic Feet (Hundreds)
Water - Cubic Feet
Load Lugger - Miles
Frond End Loader - Hours
                                   Kilowatt Hours
                                   Kilowatt Hours
                                                               267
                                                               451

                                                                28
                                                                29
                                                               109
                                                               733
                                                                27.8
                                                                 3.8

                                                              ,268
                                                               123.7
                                                              ,870
                                                                 9.8
                                                                 1.5
                                                             5,480
                                                             8,640
                                                                 3
                                                             3,114
                                                                17
                                                                12
                                                                       Overall
                                                                        Rate
                                                                        7.8
                                                                      1,257
                                                                        733
                                                                        524

                                                                        410
                                                                        218
                                                                         53%
                                   375

-------
                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
           MILLED COMBINED REFUSE - 5-IN. GRATE - SUMMER 1968
                            June 3-23, 1968*
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Total
                              766
                               93.0 hours
                                3,2 hours
                               96.2 hours
                        Tons per Hour
                                                     Operating
                                                       Rate
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 93 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                 Hours
                 (Hours) per Hundred Tons
                 Hours
Cover Dirt - Cubic Yards
Equipment Time - (Hours) per Hundred Tons
Cover Dirt - Yards per Ton
Utility and Equipment Usage
    Volt Electrical Service
440 Volt Electrical Service
Gas - Cubic Feet (Hundreds)
Water - Cubic Feet
Load Lugger - Miles
Frond End Loader - Hours
                                   Kilowatt Hours
                                   Kilowatt Hours
Overall
 Rate
 8.0
                                                              1,924
                                                                766
                                                              1,158
                                                                589
                                                                210
                                                                 36%
                                                       279
                                                       406

                                                        19

                                                       123
                                                          499
                                                           19.3
                                                            3.9

                                                        not completed -
                                                        see summary
                                                        sheet for July 29
                                                        through
                                                        August 16
                                                     6,880
                                                     9,920
                                                         6
                                                     3,629
                                                        11
                                                         8.4
*Excluded week of June 17-21 during which contract
 haulers' loads were milled.
                                    376

-------
                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
         MILLED COMBINED REFUSE - 3-1/2 IN. GRATE - SUMMER 1968
                            July 1-26, 1968*
Plant Performance
     Tons Mi 11ed
     Milling Time
     Down Time
     Total Time
     Average Production
        Total
              635
               79.3 hours
                2.8 hours
               82.1 hours
Rates - Tons per Hour
Operating
  Rate
                                     870
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 79.3 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
    "RTTled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time - Hours
 Hours
 (Hours) per Hundred Tons
        Cover Dirt - Cubic Yards
        Equipment Time - (Hours) per Hundred Tons
        Cover Dirt - Yards per Ton
Utility and Equipment Usage
     220 Volt Electrical Service
     440 Volt Electrical Service
     Gas - Cubic Feet (Hundreds)
     Water - Cubic Feet
     Load Lugger - Miles
     Frond End Loader - Hours
           Kilowatt Hours
           Kilowatt Hours
 Overal1
  Rate
T77
                                              1,311
                                                635
                                                676
                                       238
                                       450

                                        20
                                         0
                                       128
     430
      19.7
       4.6

   not complete-
   see summary
   sheet for July 29
   through
   August 16
   4,400
   8,160
       3
   2,259
     108
      18.3
*Excluding week of July 22-28 when a mixed set of 4-inch and
 5-inch grates were in the mill.
                                   377

-------
                            TABLE C (Cont.)

                      SUMMARY OF EXPERIMENTAL RUN
         MILLED COMBINED REFUSE - 6-1/4-IN. GRATE - SUMMER 1968
                       July 29 - August 16, 1968
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Total Time
     Average Production Rates
        Total
                              775 (including August 19 and 20)
                               88.8 hours
                                2.5 hours
                               91.3 hours         Operating    Overall
                        Tons per Hour               Rate        Rate
                                                     877
Refuse Quantities
     Total Quantity of Combined Refuse from all Wards - Tons
     Total Milled - Tons
     Total Unprocessed - Tons
     Total No. of Loads of Refuse Received at Site
     Total No. of Loads Milled
     Percentage of Total Loads which are Milled

Work Times
     Man-Hours of Milling - 88.8 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled
        Unprocessed
     Total Man-Hours for Compaction Equipment Operator
Landfill
     Milled
        Tons
        Equipment Time
        Equipment Time
     Unprocessed
        Tons
        Equipment Time
                 Hours
                 (Hours) per Hundred Tons
                 Hours
Cover Dirt - Cubic Yards
Equipment Time - (Hours) per Hundred Tons
Cover Dirt - Yards per Ton
Utility and Equipment Usage
     220 Volt Electrical Service
     440 Volt Electrical Service
     Gas - Cubic Feet (Hundreds)
     Water - Cubic Feet
     Load Lugger - Miles
     Front End Loader - Hours
                           Kilowatt Hours
                           Kilowatt Hours
                                                              1,312
                                                                677
                                                                635
                                                                386
                                                                185
                                                                 48%
                                                       266
                                                       413

                                                        29
                                                        57
                                                       127
  709
   17.9 (for 443 tons)
    4.0

  548
   39.6 (-for 362 tons)
1,010
   10.9
    1.8
4,040
6,560
    3
2,226
   14
    7.5
                                    378

-------
                            TABLE C (Cont.)

                      MONTHLY SUMMARY - AUGUST 1968
                MILLED COMBINED REFUSE - 6-1/4-IN. GRATE
                        August 19 - September 13
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Overall Time
     Production Rate - Tons per Hour
        Operating Rate
        Overall Rate
538
 66.2 hours
  2.6 hours
 68.8 hours

  8.1
  7.8
Refuse Quantities
     Total Tons of Combined Refuse - West Side
     Tons Milled
     Tons Unprocessed

Work Times
     Man-Hours of Milling - 66.2 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled Cell
        Unprocessed Cell
     Total Man-Hours for Compaction Operator

Landfill
     MTTled
        Tons
        Compaction Time - Hours
     Unprocessed
        Tons
        Compaction Time
        Cover Dirt - Cubic Yards

Utility and Equipment Usage
     220 Volt Electrical - Kilowatt Hours
     440 Volt Electrical - Kilowatt Hours
     Gas - Hundreds of Cubic Feet
     Water - Cubic Feet
     Front End Loader - Hours
                       1,757
                         538
                       1,219
                         199
                         590
                       no record
                         176
                       4,080
                       5,440
                           5
                       2,160
                           8.3
                                   379

-------
                            TABLE C  (Cont.)

                    MONTHLY SUMMARY - SEPTEMBER 1968
                  MILLED COMBINED REFUSE - 125 MM GRATE
                             September 16-27
Plant Performance
     Tons Milled                      357
     Milling Time                      45.8 hours
     Down Time                          1.9 hours
     Overall Time                      47.7 hours
     Production Rate - Tons per Hour
        Operating Rate                  7.8
        Overall Rate                    7.5

Refuse Quantities
     Total Tons of Combined Refuse - West Side                 870
     Tons Milled                                               357
     Tons Unprocessed                                          513

Work Times
     Man-Hours of Milling - 45.8 hours x 3 men                 137
     Total Man-Hours in Plant                                  268
     Man-Hours of Compaction                                 no record
        Milled Cell
        Unprocessed Cell
     Total Man-Hours for Compaction Operator                    91

Landfill
     Milled
        Tons
        Compaction Time - Hours
     Unprocessed
        Tons
        Compaction Time
        Cover Dirt - Cubic Yards

Utility and Equipment Usage
     220 Volt Electrical - Kilowatt Hours                    2,420
     440 Volt Electrical - Kilowatt Hours                    4,160
     Gas - Hundreds of Cubic Feet                                4
     Water - Cubic Feet                                        790
     Front End Loader - Hours                                   11.1
                                    380

-------
                            TABLE C (Cont.)

                     MONTHLY SUMMARY - OCTOBER 1968
                  MILLED COMBINED REFUSE - 5-IN. GRATE
                       September 30 - November 1
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Overall Time
     Production Rate - Tons per Hour
        Operating Rate
        Overall Rate
1,010
  126.5 hours
    5.5 hours
  132.0 hours

    8.0
    7.6
Refuse Quantities
     Total Tons of Combined Refuse - West Side
     Tons Milled
     Tons Unprocessed

Work Times
     Man-Hours of Milling - 126.5 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled Cell
        Unprocessed Cell
     Total Man-Hours for Compaction Operator

Landfill
     Milled
        Tons
        Compaction Time - Hours
     Unprocessed
        Tons
        Compaction Time
        Cover Dirt - Cubic Yards

Utility and Equipment Usage
     220 Volt Electrical - Kilowatt Hours
     440 Volt Electrical - Kilowatt Hours
     Gas - Hundreds of Cubic Feet
     Water - Cubic Feet
     Front End Loader - Hours
                         1,974
                         1,010
                           964
                           380
                           702
                         no record
                           228
                           192
                         not kept

                           687
                         not kept
                         not yet covered
                         7,100
                        11,680
                           688
                         2,845
                            11.9
                                   381

-------
                            TABLE C (Cont.)

                     MONTHLY SUMMARY - NOVEMBER 1968
                  MILLED COMBINED REFUSE - 5-IN. GRATE
                              November 4-29
Plant Performance
     Tons Milled
     Milling Time
     Down Time
     Overall Time
     Production Rate - Tons per Hour
        Operating Rate
        Overall Rate
554
 72.0 hours
  3.3 hours
 75.3 hours

  7.7
  7.4
Refuse Quantities
     Total Tons of Combined Refuse - West Side
     Tons Milled
     Tons Unprocessed

Work Times
     Man-Hours of Milling - 72.0 hours x 3 men
     Total Man-Hours in Plant
     Man-Hours of Compaction
        Milled Cell
        Unprocessed Cell
     Total Man-Hours for Compaction Operator

Landfill
     Milled
        Tons
        Compaction Time - Hours
     Unprocessed
        Tons
        Compaction Time
        Cover Dirt - Cubic Yards

Utility and Equipment Usage
     220 Volt Electrical - Kilowatt Hours
     440 Volt Electrical - Kilowatt Hours
     Gas - Hundreds of Cubic Feet
     Water - Cubic Feet
     Front End Loader - Hours
                       1,596
                         557
                       1,039
                         216
                         521
                       no record
                         156
                         517
                       not kept

                       1,046
                       not kept
                       1,520 for 1,560 tons
                       7,780
                       6,240
                       1,878
                       2,142
                          16
                                    382

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                            TABLE C  (Cont.)

                     MONTHLY SUMMARY - DECEMBER 1968
                  MILLED COMBINED REFUSE - 5-IN. GRATE
                              December 2-27
Plant Performance
     Tons Milled                      625
     Milling Time                      90.4 hours
     Down Time                          2.9 hours
     Overall Time                      93.3 hours
     Production Rate - Tons per Hour
        Operating Rate                  6.9
        Overall Rate                    6.7

Refuse Quantities
     Total Tons of Combined Refuse - West Side               1,401
     Tons Milled                                               644
     Tons Unprocessed                                          757

Work Times
     Man-Hours of Milling - 90.4 hours x 3 men                 271
     Total Man-Hours in Plant                                  650
     Man-Hours of Compaction
        Milled Cell                                             41
        Unprocessed Cell                                        66
     Total Man-Hours for Compaction Operator                   190

Landfill
     MlTled                      compaction trial with rubber-tired front end lo
        Tons                                                   644
        Compaction Time - Hours                            30.9 hours for 518 to
     Unprocessed
        Tons                                                   757
        Compaction Time                                    45.1 hours for 486 to
        Cover Dirt - Cubic Yards

Utility and Equipment Usage
     220 Volt Electrical - Kilowatt Hours                    9,880
     440 Volt Electrical - Kilowatt Hours                    7,520
     Gas - Hundreds of Cubic Feet                            2,817
     Water - Cubic Feet                                      3,414
     Front End Loader - Hours                                   43.9
                                    383

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                                   Table C (Cont.)



                              Monthly Summaries - 1969

Refuse Quantities:
Total Tons
Tons Not Milled
Tons Milled
Plant Performance:
Tons Milled
Milling Time - Hours
Shutdown Time - Hours
Overall Time
Production Rate (tons/hr.)
Operational
Overall
January February
5 weeks 4 weeks
1,285
235
1,050
402 1,050
60.7 128.7
4.1 4.0
64.8 132.7

6.9 8.2
6.5 7.9
March
4 weeks
1,317
232
1,085
1,085
123.9
5.6
129.5

8.8
8.4
April
5 weeks
2,367
877
1,490
1,490
160.9
6.1
167.0

9.3
8.9
May
4 weeks
2,021
1,146
875
875
82.4
6.2
88.6

10.6
9.9
Grate Size Opening
Sin.
4 in.
4 in.
4 in.
4 in,
                                         384

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D - Wage Rates at Madison Refuse Reduction Plant
    During Gondard Evaluations
      It has been found that the most reliable way to determine labor
cost is to compute it on an annual basis, including fringe benefits
and overtime.  Use of basic wage rates,  such as appear on payroll
sheets, do not include all the fringe benefits that may accrue to
having an employee on one's staff. For the purposes of this project,
in which it was desired to know the variation of costs associated
with different sized grates, it was found that use of labor costs obtained
from the city sanitation division could not be used. It was  not valid
to use typical payroll information because the need for a substitute
for vacation could unfairly increase the labor cost for a particular
size of grate.

      It was therefore felt that the most meaningful way to  deter-
mine labor cost is to calculate the total annual wage including base
pay, fringe benefits, substitute pay and overtime.  The annual
wage  can then be divided by the number of work hours per year
to arrive at an hourly wage  (annual average). It should be noted
that this type of accounting indicates that the fringe benefits paid
to City of Madison employees amounts to 30 percent of their basic
wage. When overtime is  added with the fringe benefits, the annual
average wage rate is 50 percent above the basic wage rate. It is
felt that recognition of these high labor costs, which are not commonly
reported in the literature, should be made when making comparisons.
The following pages  are computations made to determine the annual
average hourly wage of the three men who work at the plant, plus
the  landfill equipment operator.
                             385

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   TABLE D.  Wage Rates of Employees , Refuse Reduction Plant,
             Madison, Wisconsin (October 1, 1969)

                         WAGE RATE
(Including Base Pay, Fringe Benefits, Overtime and Substitute Pay)
                    Effective October 1, 1969
REFUSE REDUCTION PLANT  OPERATOR - basic wage rate $4.7625/hour
      20 days vacation per year
      12 sick days per year
      315 hours of overtime per year

Base Pay $4.7625/hour  x 2,080 hours/year                   $ 9,906

Overtime - 240 hours/year x $6.84/hour (time-and-a-half)      2,249

      SUBTOTAL - Base Pay  plus Overtime                   $12,155

Social Security - 4.8% x $7,800                                374

Retirement - 11.04%  x $7,800                                  861

Life Insurance - over 40 years old
      $12,000  x  $0.60/$1,000  x 12 months
        x  0.32/1.32 (city share)                               21

Health - $17.19/month x  12 months                             206

Workmen's Compensation (estimate based on two sources)	85_

      SUBTOTAL - Base Pay, Overtime and Fringe Benefits     $13,702
      (hourly wage  rate of base, overtime and fringe
      benefits is $13,702/2,080 hours = $6.59/hour)

Vacation substitute - $5.00/hour x  20 days  x 8 hours/day       800

Sick Days substitute - $5.00/hour  x 12 days x  8 hours/day      480


      TOTAL ANNUAL WAGE                                 $14,982
Hourly Wage (annual av.)  $14,982/2,080 hours = $7.20/hour
                             386

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                        TABLE D. (Cont.)

                         WAGE RATE
(Including Base Pay, Fringe Benefits, Overtime and Substitute Pay)
                    Effective October 1, 1969
EQUIPMENT  OPERATOR III - basic wage rate $4.2375/hour
      17.5 days vacation per year
      12 sick days per year
      315 hours of overtime per year

Base Pay $4.2375/hour x 2,080 hours/year                  $ 8,814

Overtime - 175 hours/year x  $6.09/hour  (time-and-a-half)      2,003

      SUBTOTAL  - Base Pay plus Overtime                   $10,817

Social Security - 4.8% x $7,800                                 374

Retirement - 11.04% x $7,800                                   861

Life Insurance (between 30 and 40 years old)
      $10,000 x  $0.40/$1,000 x 12 months
        x 0.32/1.32 (city share)                                12

Health - $17.19/month x  12 months                              206

Workmen's Compensation (estimate based on two sources)       	85_

      SUBTOTAL  - Base Pay, Overtime and Fringe Benefits    $12,355
      (hourly wage rate of base, overtime afcd fringe
      benefits is $12,355/2,080 hours = $5.94/hour)

Vacation substitute -  $5.00/hour  x  17.5 days  x 8 hours/day      700

Sick Days  substitute - $5.00/hour  x 12 days x  8 hours/day       480


      TOTAL ANNUAL WAGE                                $13,535
Hourly Wage (annual av.)  $13,535/2,080 hours = $6.51/hour
                               387

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                        TABLE D. (Cont.)

                         WAGE RATE
(Including Base Pay,  Fringe Benefits, Overtime and Substitute Pay)
                    Effective October 1, 1969
PUBLIC WORKS MAINTENANCE MAN I - basic wage rate $3.45625/hour
      12.5 days vacation per year
      12 sick days per year
      315 hours of overtime per year

Base Pay $3.45625/hour  x 2,080 hours/year                  $  7,189

Overtime - 315 hours/year x  $5.00/hour (time-and-a-half)      1,632

      SUBTOTAL  - Base Pay plus Overtime                   $  8,821

Social Security - 4.8% x $7,800                                 374

Retirement - 11.04%  x $7,800                                   861

Life Insurance (under 30 years old)
      $8,000  x $0.20/$1,000 x  12 months
         x  0.32/1.32  (city share)                                5

Health  - $17.19/month x  12 months                              206

Workmen's Compensation (estimate based on two sources)	85_

      SUBTOTAL  - Base Pay, Overtime and Fringe Benefits    $10,352
      (hourly wage  rate of base,  overtime and fringe
      benefits is $10,352/2,080 hours = $4.98/hour)

Vacation substitute - $5.00/hour  x 12.5 days x 8 hours/day      500

Sick Days substitute - $5.00/hour  x 12 days  x  8 hours/day       480


      TOTAL ANNUAL WAGE                                $11,332
Hourly Wage (annual av.)  $11,332/2,080 hours = $5.45/hour
                              388

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                        TABLE D. (Cont.)

                         WAGE RATE
(Including Base Pay, Fringe Benefits , Overtime and Substitute Pay)
                   Effective October 1,  1969
LANDFILL OPERATOR - basic wage rate $4.175/hour
      20 days vacation per year
      12 sick days per year
      — hours of overtime per year

Base Pay $4.175/hour  x 2,080 hours/year                   $ 8,684

Overtime -     hours/year  x  $   /hour  (time-and-a-half)        —

      SUBTOTAL - Base Pay plus Overtime                   $ 8,684

Social Security - 4.8%  x $7,800                                 374

Retirement - 11.04%  x $7,800                                   861

Life Insurance
      $9,000  x $0.60/$1,000 x 12 months
         x  0.32/1.32  (city share)                               16

Health - $17.19/month x  12 months                             206

Workmen's Compensation (estimate based on two sources)      	85

      SUBTOTAL - Base Pay, Overtime and Fringe Benefits    $10,226
      (hourly wage rate of base, overtime and fringe
      benefits is $10,226/2,080 hours = $4.93/hour)

Vacation substitute - $5.00/hour x  20 days x 8 hours/day        800

Sick Days substitute - $5.00/hour x 12 days  x 8 hours/day      480


      TOTAL ANNUAL WAGE                               $11,506
Hourly Wage (annual av.)  $11,506/2,080 hours  = $5.53/hour
                              389

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E - Gondard Hammer Wear and Costs
     Results with 4-inch grates show a set of hammers can last 1,200 tons
with dally hard facing, as necessary.  Based on previous work, a set of
hammers used with 5 and 6-1/4 Inch grates will have a life calculated as
follows:

     4-inch grate:  1200 tons

Based on differences in production rates:

                    9.0-8.4
     5-inch grate:    8.4   tons/hour * 7.1% increase

                 1.071 x 1200 = 1285, or 1300 tons/set

     6-1/4 inch grate:  9.4-8.4 tons/hour = 11.956 increase
                          8.4

                 1.119 x 1200 - 1430 or 1450 tons/set


     Welding initially takes 10 rods of Amsco Super 20.  Daily touch up
requires 5 additional rods each time.  The hammers lasting 1200 tons were
retouched 14 times.  The cost of hammers with salvage value subtracted has
previously been computed at $145.

     A 50-lb. box of Amsco Super 20, 3/16-inch electrodes costs $1.80/lb.
and contains 180 rods.

     Cost per Rod:  50 Ib. @ $1.80 = $90 or $.50/rod

     The number of rods required for use with the 4-inch grate is

     10 original + (14 touch-ups x 5) - 80 rods @ $.50 = $40.

     More frequent touching up will be required with the larger grates
because more tonnage 1s being milled.  The increase in rods used for
touch up is calculated as:

     5-inch grate:  1.07 x 70 = 75 + original 10 = 85 @ $.50 = $42.50

     6-1/4 inch grate:  1.12 x 70 = 80 + original 10 = 90 @ $.50 = $45

     The annual cost of hammers includes the cost of hammers minus salvage
plus welding rods.
                                   390

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The number of sets of hammers used annually is:

               10,750 tons/.yr.
4-inch grate:   1,200 tons/set  = y sets/year

               11.520 tons/yr.   .   .  .
5-inch grate:   1,300 tons/set = 9 sets/year

                  12,030 tons/yr.
6-1/4 inch grate:  1,450 tons/set = 9 sets/year
The annual  cost is:


Cost of Hammers
Cost of Welding Rods
Number of Sets
Annual Cost of Hammers
And Welding Rods
Annual Tonnage
Cost Per Ton

4-Inch
$ 145/set
40/set
$ 185/set
x 9
$ 1,665
$10,750
$ 0.16
Grate Size
R-Tnr.h
$ 145/set
42/set
$ 187/set
x 9
$ 1,683
$11,520
$ 0.15

6-1/4 Inch
$ 145/set
45/set
$ 190/set
x 9
$ 1,710
$12,030
$ 0.14
                              391

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F - Analysis of Gondard Plant Shutdowns
      The following table lists the days that the plant was shut down
and the reasons for the shutdown and the probable solution for this type
of shutdown.  The plant was operating every day from September 18,
1967 through May 31, 1969, excepting the dates noted below.  The conclusion
to be drawn from the following table is that most all shutdowns of this
pilot plant could be remedied in future plants through proper  design
and by scheduling maintenance not to interfere with daily production.
  Date
 (Starting
  9-18-67)

 9-22-67
 10-18-67
 1-2-68
 1-9-68
 1-10-68

 3-1-68
  thru
 3-12-68
      Reason

Truck broke down and did
not operate properly when
repaired by the garage.
Demonstration for Wiscon-
sin League of Municipalities
Changed grates and in-
stalled hammers.  The
plant operator attended
a meeting to reevaluate
jobs at plant.

A new discharge chute was
constructed under the mill.

Head shaft on elevating
conveyor broke.  A strong-
er pulley was constructed
and installed.  The reject
chute was also changed.
   Solution or Possibility
      of Recurrence

Truck breakdowns will occur
periodically.  A standby truck
should be kept on site,  or
arrangements made to obtain
a spare from the collection
truck fleet.

Demonstrations would not need
to take a full day, if the plant
was not cleaned thoroughly.

Grate and hammer work could
be done on overtime.
Proper initial construction.
This problem has not recurred
since a stronger head shaft
pulley was installed.
                                  392

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  Date          Reason

3-19-68     Haul roads were being
            built.
4-24-68     Two men were sick.
            Cleaned plant, touched
            up surface hardening on
            hammers, and prepared to
            mill all of the next day's
            refuse.

6-28-68     Changed grates for experi-
            mental purposes.
7-26-68     Made mill repairs ,  changed
            grates, filled in drainage
            trough and changed
            hammers.

8-2-68      The variable speed drive
8-5-68      belt in the motor for the
            elevating conveyor broke.
   Solution or Possibility
     of Recurrence

Can be eliminated by providing
drainage,  and planning for
wet weather operations.

The plant  should operate
with substitutes .  However,
the plant was purposely pre-
pared for  milling all the re-
fuse collected the next day.
Grates would not be changed
as frequently as was done for
experimental reasons and could
be done on overtime.

Periodic repairs are
necessary but should be
done on overtime, or
subcontracted.

The drive belts will wear
with time and will have to
be replaced periodically.
However,  this belt wore faster
than expected.
End of Experimental Runs

8-21-68     Repair the mill and place
 t^ru       vertical sides on part of
8-29-68     the pan feeder.
9-13-68     Changed grates for
            experimental purposes.
Mill repairs are periodically
required (see note for
7-26-68) .  Constructing the
pan feeder with vertical sides
would eliminate need for this
modification.

See note for 6-28-68.
                                 393

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  Date          Reason

9-26-68     Repair the wear plates in
9-27-68     the mill.

10-23-68    The grates and wear plates
            in the mill were built up
            and hard surfaced.

11-1-68     Repair mill. A broken
 thru       spacer shaft was replaced
11-7-68     and new spacer rings were
            installed.  Also,  the wear
            plates were resurfaced  and
            the reject chute repaired.

11-18-68    Mass sick call because of
            city wage dispute.

11-21-68    The rotor of the mill was
            rebalanced.

1-13-69     Cleats were placed on the
 thru       transverse conveyor to
1-17-69     aid the flow of refuse.
1-22-69     A haulaway truck had to
            be taken to Milwaukee for
            repair of a broken part.

1-31-69     A new wear plate had to
            be placed in mill when at-
            tempts to patch old plate
            were unsuccessful.

3-28-69     Sympathy strike with
            city firemen.
    Solution or Possibility
       of Recurrence

See note for 7-26-68.
See note for 7-26-68.
New shafts and spacers will
occasionally be needed.
Also,  see note for 7-26-68.
See note for 7-26-68.
Proper initial construction.
Maintenance could be sched-
uled during other major
repairs.

Have an unused truck from
collection fleet ready for
emergency use.

Repair plates before they get
completely worn.
                                  394

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  Date            Reason

4-3-69      Reconstruct reject chute
 and        to telescope out of way to
4-4-69      facilitate maintenance on
            the mill.

5-5-69      Removed excessively worn
            wear plates and made re-
            placements .  Also changed
            hammers.

5-12-69     Replacement of the return,
 thru       guide track of the bin con-
5-15-69     veyor which wore and
            broke.
5-29-69     Cleaned entire plant;
            hard-surfaced the hammers;
            and made mill repairs.
   Solution or Possibility
       of Recurrence

Proper initial design.
More frequent attention and
scheduling of work.
Heavier initial construction.
More frequent inspection and
lubrication. Scheduling of
necessary repairs at same
time as other major repairs.

This should be scheduled
over several working days.
                                 395

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G - Cost Comparison of Hammer Tipping Versus Non-Tipping


     From observations and practical  experience 1t is known that tipping
of hammers reduces hammer wear and appears to save money,  but no data
have been recorded to support these observations.   To get  such data, two
ten-day periods were set up to compare normal milling operations using
the Tollemache Mill.  The first period was completed using untipptd ham-
mers, the second using tipped hammers.  Data were  kept almost exclusively
by plant personnel and consisted of the number of  hammers  used, welding
rods used, and labor involved in changing and tipping hammers.

Cost Comparison

     It was felt that for the purposes of this study the most meaningful
comparisons could be obtained on a cost-per-ton basis.  Costs considered
will be for materials used and for labor expended  during the two test
periods.  Other costs do enter into the comparison, such as depreciated
value of welding equipment, electrical costs, etc., but these costs are
nominal in comparison to labor and material costs.  Table    G-l shows a
comparison of material costs for Period I (no tipping) and Period II
(tipping applied).
                                    396

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                               Table   G-l

                         Cost of Materials  Used

            Hammers  Rods           Welding    Total      Tons    Cost Per
  Period**   Used    Used  Hammers   Rods     Net Cost  Milled    Ton

    I         80       0    $249     $ 0       $249      610     $0.408

   II         34      53     102      27        129      644      0.200
**Period I - January 21 to February 3, 1971, no tipping
  Period II -February 4 to February 17, 1971, hamners tipped


     Table   G-l  shows that cost of materials during Period I  was  almost
twice that of Period II, indicating a significant gain by tipping  hammers
Further comparison is made with respect to labor costs in Table   G-2.
                               Table   G-2

                          Cost of Labor Used
                Total  Hours       Hours/Week     Total   Tons     Cost per
             Operational   Man  Operational   Man  Cost  Milled      Ton
Period I
Changing
Period II
Hammer
Changing
Hammer
Tipping
Totals for
Period II

7.75 15.5 3.35 7.75 $108 610 $0


4.5 9.0 2.25 4.50 63 644 $0

4.7 4.7 2.35 2.35 33 644 0

9.2 13.7 4.60 6.85 $ 96 644 $0

.177


.098

.051

.149
                                   397

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     Table   G-3 presents a  comparison of the total  cost of the
hammer maintenance programs for both Period I and Period II.
                               Table   G-3

                Total Cost of Hammer Maintenance Program
   Hammers

   Welding Rods

   Labor (Hammer
    Changing)

   Labor (Hammer
    Tipping)

   TOTAL
    Period I
Nontipped Hammers

Cost     Cost/Ton

$249      $0.408

  0          0
 108
0.177
             0

          $0.585
              Period II
            Tipped Hammers

           Cost     Cost/Ton

           $102      $0.159

             27       0.042
63
0.098
                      0.051

                     $0.350
     A significant savings of over 03 cents per ton is indicated in
Table   G-3.  At a rate of 50,000 tons of refuse milled per year,
the city can save $11,500 by tipping the mill  hammers.

     There were some indications that the figure of 23 cents per ton
may be conservative.  For instance, when no tipping program was in
force, plant personnel neglected to check regularly the inside of
the mill.  Consequently, hammers were not changed as often as they
should have been, resulting in a larger particle size for the end
product.  Although particle size is not considered as a means of
determining when to change hammers, a larger than desirable particle
size does result from badly worn hammers.
                                   398

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 H - Annual Tolletnache Depreciation Date for Milling and Hauling Systems

             (Applicable to Test Periods I  and  II  Exclusively)



      Depreciation or annual cost as presented  In  Table   H-l, Annual
 Depreciation Data for Milling System, and  Table   H-2,  Annual Deprecia-
 tion for Stationary Compactor and Final Transportation  System,  is
 computed using the following equation*:

                      A.C. = (P-L) (CRF - 1% -  n)  + Li

      where; A.C. = Annual Cost

               P  = Initial Investment

               L  = Salvage Value

             CRF  = Capital Recovery Factor

               1% = Interest Rate

               n  = Rated Full Life

 The interest rate is a function of the expenditure involved.  The  city
 of Madison, Wisconsin will find the purchases  of  equipment for  the plant
 by either long-term or short-term notes.  The  larger expenditures  are
 usually paid by bonds and the saaller by notes.  The interest rates in
 effect at the time the evaluations took place  were 5.9% on bonds and
 6.5% on notes.  Tables   H-l and   H-2 contain all pertinent data  in
 respect to depreciation computations.
*Grant, E.  L.,  and W.  G. Ireson,   Principles of  engineering  economy
      4th ed.   New York,  the  Roland Press Company,  1964.   574  p.
                                    399

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                               Table   H-l

                  Annual  Depreciation Data  for Milling  System
                      Original   Effective  Interest  Salvage   Annual
         Item           Cost    Life (Yrs)    Rate     Value    Cost

   Building and
    Foundation        $133,118      20        5.9%    $4,000   $11,390

   Tollemache Mill
    and Conveyors       87,600      15        5.9%     4,000     8,640

   Scale                 5,916      20        6.5%     1,000       600

   Front-End
    Loader              15,400      12        6.5%     3,000     1.700

   TOTAL                                                      $22,390


     The total annual  cost of $22,970 can be proportioned  to  the 14
week and 8 week evaluation periods on a  straight line basis.   Depreciation
for the 14 tfeek evaluation is 14/52 ($22,390) = $6,034 and for the 8  week
period 8/52 ($22,390)  = $3,448.
                               Table   H-2

         Annual Depreciation Data for Stationary Compactor and
                       Final Transportation System
                      Original  Effective  Interest  Salvage  Annual
         Item           Cost    Life (Yrs)    Rate     Value    Cost

   Stationary
    Compactor and
    Hopper             $19,150     15        6.5%    $1,000    $2,000

   Two Trailers         33,000     12        6.5%     1,500     3,960

   One Tractor          13,625     15        6.5%     1,500     1,390

   Building Addition    16,801     20        6.5%     1,000     1.500

   TOTAL                                                       $8,850
                                   400

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     As with the milling system, the annual  cost computed  In  Table
H - 2 can be proportional to the 14 and 8 week evaluation  periods.
The results are a depreciation cost of $2,385 for 14 weeks and
$1,360 for 8 weeks.
                                   401

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         ][ - Supplemental Data - Tollemache Experimental Run

               Period 1  (July 6, 1970  -  October  9,  1970)


                               Table   1-1

                       Summary of Experimental Run

            Tollemache Mill,  July 6, 1970 - October 9,  1970
PLANT PERFORMANCE

   Tons Milled                                           5,406.0
   Milling Time - Hours                                    365.8
   Down Time - Hours                                         9.5
   Total Time - Hours                                      375.3
   Production Rates - Tons per Hour               Operating  Overall
                                                    14.53     14.18 "

REFUSE QUANTITIES

   Total Tons Received at Site                           6,406
   Total Milled - Tons                                   5,318
   Total Unprocessed - Tons                              1,088
   Percentage Milled                                        83%

MAN-HOURS PER WEEK (AVERAGE)

   Regularl                                                126
   Overtime                                                 12

UTILITY AND EQUIPMENT USAGE

   220 Volt Service - Kilowatt Hours                    13,760
   440 Volt Service - Total Kilowatt Hours              33,968
   440 Volt Service - Mill - Kilowatt Hours              2,670
   Water Cubic Feet
   Gas Cubic Feet                                        6,000
   Front-End Loader - Hours                                 85.6
   Tractor No. 586 - Miles                                  —
   Transfer Trailers - No. 760 - Hours                      14.4
                     - No. 761 - Hours                      13.7
1 Includes 6 hours per week supervision,


                                   402

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                                Table   1-2

                           Table of Labor Rates

                          Effective July 6, 1970



                                      Basic Hourly     Average Annual
           Position                      Wage *         Hourly Wage**

    Plant Foreman                        $5.26             $7.37

    Mill Operator I                      $4.72             $6.78

    Public Works Maintenance Man I       $4.21             $6.24
 *Does not include fringe benefits.
**Includes basic hourly wage, fringe benefits,  overtime and
  substitute pay per employee as follows:

  1) Social  Security - 4.8% on first $7,800
  2) Retirement - 11.04% on first $7,800
  3) Health  Insurance - $17.19 per month (family plan)
  4) Life Insurance - ranges from $5.00 to $21.00 per year as
     age of  employee increases
  5) Vacation Substitute - $500/yr.  to $800/yr. depending  on
     length  of service
  6) Sick Day Substitute - $480/yr.
  7) Overtime - based on estimated hours of overtime allotted
     each employee per year:

         200 hrs/yr - Foreman
         225 hrs/yr - Mill Operator
         300 hrs/yr - Maintenance Man I

 The method  used to compute the average annual  wage is  contained  in
 Appendix   K.
                                    403

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                            Table   1-3
                     Power and Utility Rates

220 SERVICE
    Demand Charge - Ftrst 10 kw or less per month          $  .75
                  - Over 10 kw per month per kw            $1.70
    Energy Charge - First 500 kwh per month per kwh        $  .0233
                  - Next 9,500 kwh per month per kwh       $  .0165
                  - Next 10,000 kwh per month per kwh      $  .0140
440 SERVICE
    Demand Charge - First 10 kw or less per month          $1.70
                  - Next 90 kw per month per kw            $1.70
                  - Over 100 kw per month per kw           $  .85
    Energy Charge - First 1200 kwh per month per kwh       $  .0233
                  - Over 1200 kwh per month per kwh        $  .009


                            Table   1-4
                    Equipment Maintenance Rates
               Tractor                    $0.15/mile
               Transfer Trailers          $0.50/hour
               Front-End Loader           $3.40/hour
                                404

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   J_ - Supplemental Data - Tollemache Experimental Run - Period 2

                 (February 4, 1971  to March 31,  1971)



                              Table   J-l

                      Summary of Experimental  Run

          Tollemache Mill, February 4, 1971 to March 31, 1971


  PLANT PERFORMANCE

      Tons Milled                                    2,624
      Milling Time - Hours                             204.5
      Down Time - Hours                                  4.2
      Total Time - Hours                               208.7
      Production Rates - Tons per Hour       Operational     Overall
                                                12.83         12,58

  REFUSE QUANTITIES

      Total Tons Received at Site                    2,640
      Total Milled - Tons                            2,624
      Total Unprocessed - Tons                          16
      Percentage Milled                                 99%

  MAN-HOURS PER WEEK (AVERAGE)

      Regular1                                         128
      Overtime                                          11.3

  UTILITY AND EQUIPMENT USAGE

      220-Volt Service - Kwh                        12,710
      440-Volt Service - Overall - Kwh              29,280
      440-Volt Service - Mill - Kwh                 23,136
      Water - Cubic Feet                             2,850
      Gas - 100 Cubic Feet                           4,640
      Front-End Loader - Hours                          48.3
      Tractor No. 586 - Miles                          178.3
      Transfer Trailer - No. 760 - Hours                 4.8
                       - No. 761 - Hours                 6.9
Includes 8 hours per week supervision
                                  405

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                               Table   J-2

                          Table of Labor Rates

                        Effective January 1, 1971



                                       Basic Hourly     Average Annual
             Position                     Wage*         Hourly Wage**

    Plant Foreman                         $5.66             $7.94

    Mill Operator I                       $4.72             $6.78

    Public Works Maintenance Man I        $4.21             $6.24
 *Does not include fringe benefits.
**Includes basic hourly wage, fringe benefits,  overtime and
  substitute pay per employee as follows:

  1)  Sociil Security - 5.2% on first $7,800
  2)  Retirement - 4.5% on first $7,800, 7.0% on remaining.
  3)  Health Insurance - $27.40 per  month (Family Plan).
  4)  Life Insurance - ranges from $12 to $37 per year as age
                       of employee increases.
  5)  Vacation Substitute - $700 to  $1200 per year depending
                            on length of service
      Sick Day Substitute - $480 per year.
      Overtime - based on estimated  hours of overtime allotted
                 each employee per year:  200 hrs./yr. - Foreman
                                          225 hrs//yr. - Mill Operator
                                          300 hrs./yr. - Maintenance Man I
  6)
  7)
The method used to compute annual
wage is contained in Appendix   K.
                                   406

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                            Table   J-3
                      Power and Utility Rates
220 SERVICE
    Demand Charge - First 10 kw per month                $1.00
                  - Next 490 kw per month per kw         $2.00
                  - Next 500 kw per month per kw         $1.75
                  - Next 1000 kw per month per kw        $1.10
                  - Over 200 kw per month per kw         $0.80
    Energy Charge - First 500 kwh per month per kwh      $0.0260
                  - Next 9500 kwh per month per kwh      $0.0183
                  - Next 10,000 kwh per month per kwh    $0.0150
                  - Next 30,000 kwh per month per kwh    $0.0120
                  - Next 50,000 kwh per month per kwh    $0.0100
                  - Over 100,000 kwh per month per kwh   $0.0095

440 SERVICE
    Demand Charge - First 10 kw or less per month        $2.00
                  - Next 90 kw per kw per month          $2.00
                  - Next 900 kw per kw per month         $1.00
                  - Over 1000 kw per kw per month        $0.80
    Energy Charge - First 500 kwh per month per kwh      $0.0260
                  - Next 1000 kwh per month per kwh      $0.0150
                  - Next 8500 kwh per month per kwh      $0.0110
                  - Next 90,000 kwh per month per kwh    $0.0100
                  - Over 100,000 kwh per month per kwh   $0.0095
                                407

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                         Table   J-3 (cont.)

GAS SERVICE
    Fixed Charge                                         $0.750
      - First 2,000 cu. ft. per month per 100 cu.  ft.     $0.135
      - Next 3,000 cu.  ft.  per month per 100  cu.  ft.      $0.126
      - Next 195,000 cu. ft. per month per 100 cu.  ft.    $0.0965
      - Over 200,000 cu. ft. per month per 100 cu.  ft.    $0.081
                            Table   J-4
                     Equipment Maintenance Rates

               Tractor No.  586                 $Q.20/mile
               Front-End Loader                $4.25/hour
               Transfer Trailers               $0.65/hour
                                408

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K - Wage Rates Effective July 1. 1972
                               Table   K-l

                       Average Annual  Hourly Wage
Supervisor

Foreman, 1st Shift
Operator, 1st Shift
Maintenance Man, 1st Shift

Foreman, 2nd Shift
Operator, 2nd Shift
Maintenance Man, 2nd Shift
Fringes
Included
Per/Hr.

$6.2539

 8.0154
 7.2083
 6.1986

 7.2280
 6.8932
 6.4478
Plant Average (not including supervisor)   $6.9927
  No
Fringes
Per/Hr.

$5.1745

 5.6375
 4.9500
 4.2229

 5.1000
 4.8000
 4.3654

$4.8440
                                   409

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                               Table   K-2

                    Average Annual Hourly Wage Rates

                        (Effective Jane 30, 1972)
REFUSE REDUCTION PLANT SUPERVISOR

       Basic Wage Rate:  $5.1745/hour
       12 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $5.1745/hour x 2,080 hours/year                      $10,763
Overtime:  $7.7617/hour x 100 hours/year                            776

       Subtotal                                                 $11,539

Social Security:  5.2% x $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $2,539                                     178
Health Ins.:      0.667 x $48.66/mo.  x 12 mo./yr.                    389
Life Insurance:   $1.88/mo.  x 12 mo./yr.                        	23_

       Subtotal                                                 $ 1.463

       TOTAL                                                    $13,002

                           $13 002
     Average Hourly Wage  2080 hrs/yr = $6.2539/hour
REFUSE REDUCTION PLANT FOREMAN - FIRST SHIFT

       Basic Wage Rate:  $5.6375/hour
       22 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $5.6375/hour x 2080 hours/year                       $11,726
Overtime:  $8.4563/hour x 200 hours/year                          1,691

       Subtotal                                                 $13,417

Sociil Security:  5.2% H $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $4,417                                     309
Health Ins.:      0.667 x $48.66/mo x 12 mo./yr.                     389
Life Insurance:   $3.68/mo. x 12 mo./yr.                        	44_

       Subtotal                                                 $ 1,615

Vacation Substitute 22 days x 8 hr/day x $6.00/hr.                1,056
Sick Leave Substitute 12 days x 8 hrs./day x $6.00/hr.              576

       TOTAL                                                    $16.664


                            $16.664        *Q
      Average Hourly Wage 2080 hrs./yr.    *»-
                                    410

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REFUSE REDUCTION PLANT OPERATOR - FIRST SHIFT

       Basic Wage Rate:  $4.9500/hour
       19.5 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $4.9500/hour x 2080 hours/year                       $10,296
Overtime:  $7.4250/hour x 225 hours/year                          1.671

       Subtotal                                                 $11,967

Social Security:  5.2% x $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $2,967                                     208
Health Ins.:      0.667 x $48.66/mo. x 12 mo./yr.                    389
Life Insurance:   $3.10/mo. x 12 mo./yr.                             37

       Subtotal                                                 $ 1,507

Vacation Substitute 19.5 days x 8 hrs./day x $6.00/hr.               936
Sick Leave Substitute 12 days x 8 hrs./day x $6.00/hr.               576

       TOTAL

           Average Hourly Wage 2080 hrs./yr. = $7.2083/hour
REFUSE REDUCTION PLANT MAINTENANCE MAN - FIRST SHIFT

       Basic Wage Rate:  $4.2229/ hour
       12 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $4.2229/hour x 2080 hours/year                       $ 8,784
Overtime:  $6.3343/hour x 250 hours/year                          1,584

       Subtotal                                                 $10,368

Social Security:  5.2% x $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $1,368                                      96
Health Ins.:      0.667 x $48.66/mo. x 12 mo./yr.                    389
Life Insurance:   $0.75/mo. x 12 mo./yr.                        	9_

       Subtotal                                                 $ 1,367

Vacation Substitute 12 days x 8 hrs./day x $6.00/hr.                576
Sick Leave Substitute 12 days x 8 hrs./day x $6.00/hr.               576

       TOTAL                                                    $12.887

                                 $12 887
           Average Hourly Wage 2080 hrs./yr.= $6.1986/hr.
                                   411

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REFUSE REDUCTION PLANT FOREMAN - SECOND SHIFT

       Basic Wage Rate:  $5.1000/hr.
       17 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $5.1000/hr. x 2080 hours/year                        $10,608
Overtime:  $7.6500/hr. x 200 hours/year                         	1.530

       Subtotal                                                 $12,138

Social Security:  5.2% x $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $3,138                                     220
Health Ins.:      0.667 x $48.66/mo.  x 12 mo./yr.                    389
Life Insurance:   $1.22/mo.  x 12 mo./yr.                        	1_5

       Subtotal                                                 $  1,497

Vacation Substitute 17 days  x 8 hrs./day x $6.00/hr.                 816
Sick Leave Substitute 12 day x 8 hrs./day x $6.00/hr.                576

       TOTAL                                                    $15,027
                              „ $15.027      _ t                	
          Average Hourly Wage 2080 hrs./yr.  " v-
REFUSE REDUCTION PLANT OPERATOR - SECOND SHIFT

       Basic Wage Rate:  $4.8000/hour
       14.5 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $4.8000/hour x 2080 hours/year                       $ 9,984
Overtime:  $7.2000/hour x 225 hours/year                        	1.620

       Subtotal                                                 $11,604

Social Security:  5.2% x $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $2,604                                     182
Health Ins.:      0.667 x $48.66/mo.  x 12 mo./yr.                    389
Life Insurance:   $0.94 mo. x 12 mo/yr.                         	1]_

       Subtotal                                                 $ 1,455

Vacation Substitute 14.5 days x 8 hrs/day x $6.00/hr.                696
Sick Leave Substitute 12 days x 8 hrs/day x $6.00/hr.                576

       TOTAL                                                    $14.331
                                 $14.331                        	
          Average Hourly Wage  2080 hrs./yr. = $6-8932/hr-
                                  412

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REFUSE REDUCTION PLANT MAINTENANCE MAN - SECOND SHIFT

       Basic Wage Rate:  $4.3654/hour
       14.5 days paid vacation per year
       12 days paid sick leave per year

Base Pay:  $4.3654/hour x 2080 hours/year                       $ 9,080
Overtime:  $6,5481/hour x 250 hours/year                          1.637

       Subtotal                                                 $10,717

Social Security:  5.2% x $9,000                                     468
Retirement:       4.5% x $9,000                                     405
                  7.0% x $1,717                                     120
Health Ins.:      0.667 x $48.66/mo. x 12 mo./yr.                    389
Life Insurance:   $2.82/mo. x 12 mo./yr.                        	34_

       Subtotal                                                 $ 1,416

Vacation Substitute 14.5 days x 8 hrs/day x $6.00/hr.               696
Sick Leave Substitute 12 days x 8 hrs/day x $6.00/hr.               576

       TOTAL                                                    $13.405


          Average Hourly Wage 2080 hrs./yr.  = $6.4478/hour
                                   413

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      L - Annual Two-Mill. Two-Shift Depreciation Data For Milling and Hauling Systems
                             (January 1  to July 1,  1972)
           Depreciation or annual  cost for both the milling and  hauling systems
      is presented in Tables   L-l  and   L-2.   Calculations are  based  on the
      annual cost equation used in Appendix   H.   The interest rates used for
      these calculations are those that were in effect on August 17, 1972.
      These rates are 4.0 for long term bonds  and 3.9 on short term notes.
                                     Table   L-l
                     Annual Depreciation Data For Milling System
       Item
Building and Foundation
Building Expansion
Gondard mill and Conveyors
Tollemache Mill and Conveyors
Scale
Front End Loader
Floor Sweeper
    TOTAL
                                            Effective Interest
Original
Cost
$133,118
98,000
126,705
87,600
5,916
32,115
3,462
Life
(.Vrs.)
20
20
15
15
20
12
10
Rate
(%)
4.0
4.0
4.0
4.0
3.9
3.9
3.9
Salvage
Value
$ 4,000
3,500
4,000
4,000
1,000
10,000
500
Annual
Cost
$ 9,660
7,090
11,200
7,680
400
2,730
380
$39.140
           Total annual costs for the milling system are $39,140.   Proportioning
      this to the 6-month operation yields a depreciation cost of  $19,570.
                                         414

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                                     Table   L-2             *
               Annual Depreciation Data For Stationary Compactor And
                             Final Transportation System
                                            Effective Interest
       Item
Stationary Compactor and
 Hopper
Two Trailers
Two Tractors
Building Addition
    TOTAL
Original
Cost
$19,150
33,000
30,300
16,800
Life
(Yrs.)
15
12
15
20
Rate
(%)
3.9
3.9
3.9
3.9
Salvage
Value
$1 ,000
1,500
3,000
1,000
Annual
Cost
$1 ,640
3,400
2,530
1,190
$8.760
           Total annual cost for the hauling is $8,760.  Again, propor-
      tioning this to 6 months'  operation gives a value of $4,380.
                                         415

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M - Supplemental Data—Two-Mill, Two-Shift Operation
                 (January 1 to July 1, 1972)

                         TABLE M-l

                   Power and Utility Rates

440 SERVICE - STANDARD POWER

Demand Charge -  First 10 kw or less per month          $2.00
                 Next  90 kw per kw per month          $2.00
                 Next  900 kw per kw per month         $1.00
                 Over 1,000 kw per kw per month       $0.80

Energy Charge -  First 500 kwh per month per kwh        2.60$
                 Next  1,000 kwh per month per kwh      1.501:
                 Next  8,500 kwh per month per kwh      1.10*
                 Next  90,000 kwh per month per kwh     1.00*
                 Next  100,000 kwh per month per kwh    0.95*


220 SERVICE - COMMERCIAL LIGHTING  AND POWER

Demand Charge -  First 10  kw or less per month          $1.00
                 Next  490 kw per kw per month         $2.00
                 Next  500 kw per kw per month         $1.75
                 Next  1,000 kw per kw per month       $1.10
                 Over 2,000 kw per kw per month       $0.80

Energy Charge -  First 500 kwh per month per kwh        2.60*
                 Next  9,500 kwh per month per kwh      1.83*
                 Next  10,000 kwh per month per kwh     1.50*
                 Next  30,000 kwh per month per kwh     1.20*
                 Next  50,000 kwh per month per kwh     1.00*
                 Over 100,000 kwh per month per kwh   0.95*

GAS SERVICE
Fixed charge                                          75.0*
First 2,000 cu.ft. per month per 100 cu.ft.                13.5*
Next 3,000 cu.ft. per month per 100 cu.ft.                12.6*
Next 195,000 cu.ft. per month per 100 cu.ft.              9.65*
Over 200,000 cu.ft. per month per 100 cu.ft.              8.1*
                            416

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                   TABLE M-2

           Equipment Maintenance Rates
Front End Loader                   $4.25/hr.
Tractors No. 586 and No. 587        $0.20/mi.
Transfer Trailers                   $0.25/mi.
                      417

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N - Cost Projections  For New Milll'rt& Plattts and


     This segment of the report includes detailed data in respect to
operating requirements and cost projections for a combination of one
through four mills operated either one or two operating shifts with
one maintenance shift.  The estimates given in this portion of the
reporc are based on data collected utilizing the Tollemache vertical
shaft hammermill in Madison, Wisconsin.  It is important to realize
that the cost projections  have been developed on the basis of costs
at Madison.  The wage rates, power and utility rates, depreciation, etc.
are all based on 1972 Madison cost data.  To arrive at projected costs
for similar operations an economic study following the lines of that pre-
sented below may be made using the appropriate base rates as applied to
the area being studied.

Basic Design Criteria

     The following design criteria were used in plant design and eventual
cost projections:

     (1)  Each mill will operate an average of 7 hours per shift at
          a rate of 14 tons per hour.

     (2)  The plant will operate 245 days or 49 weeks per year.  Three
          weeks are allowed for repairs and breakdowns.

     (3)  The milling production day (one or two milling shifts) will
          be followed by an eight-hour maintenance shift.

     (4)  Each plant will have as many feed conveyors as mills.  One
          and two mill plants will have one discharge conveyor and one
          stationary compactor.

     (5)  Plants containing 3 or 4 mills will have two discharge con-
          veyors and two stationary compactors.

     (6)  Cost projections are primarily based on pilot plant and
          two shift studies conducted with the equipment mentioned
          in the text.

     (7)  All pertinent data as to wage rates, utility rates,
          depreciation, etc. are based on the evaluation data
          from Madison.

Annual Tonnage

     Each Tollemache mill operating one shift will have a daily capacity
of 14 tons/hour x 7 hours/day, or approximately 100  tons per day.  The
corresponding annual tonnage for one mill shift will be 100 tons/day x
                                  418

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245 days/year = 24,500 tons per year.  Daily and annual tonnages for
combinations of mills and shifts are listed in Table N-l.

                                TABLE N-l

                 Daily and Annual Tonnage Processed for
                   Combinations of Mills and Shifts

                                       Number of Mills
                            1234
One Shift
     Daily Tonnage         100        200         300         400
     Annual Tonnage      24,500     49,000      73,500      98,000

Two Shifts
     Daily Tonnage         200        400         600         800
     Annual Tonnage      49,000     98,000     147,000     196,000

Sizeof Plant

     Experience has shown refuse quantities to vary throughout the year.
Peak tonnage rates are about 1.5 times the average daily tonnage.  Good
plant design involves increasing available storage to allow for mill
breakdowns, etc.  A factor about 1.5 times the average daily tonnage
through the plant is used to determine storage space.  The maximum storage
requirement then becomes 150 percent of the average daily tonnage processed
on a one shift basis and is reduced to 125 percent of the daily tonnage
processed on a two shift basis.  The reduction in excess capacity is due
to an increase in scale.

     The maximum storage which must be provided is listed in Table N-2
The values in Table N-2 were determined by multiplying the daily tonnage
in Table N-l by 150 percent for plants operating one shift, and by 125 per-
cent for plants operating two shifts.

                                TABLE N-2

                   Maximum Storage Requirements for
                Combinations of Mills and Shifts - Tons

                                  Number of Mills
1
150
250
2
300
500
3
450
750
4
600
1,000
     One Shift

     Two Shifts

     Assuming a density of 400 pounds per cubic yard on the dumping floor,
and an average stacked storage height of 8 feet, 0.53 ton can be stored per
square yard of floor space, or 0.059 tons per square foot of floor space.
The square footage of floor storage is computed by dividing the tonnages
in Table N-2 by 0.059 ton per square foot.
                                   419

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                                TABLE N-3

             Square Footage of Floor Storage Space Required
                  For Combinations of Mills and Shifts

                                    Number of Mills
                             1         2         3         ^
     One Shift             2,500     5,000     7,500    10,000

     Two Shifts            4,300     8,500    12,700    17,000

     The total plant size including refuse storage space on the floor, con-
veyors and mills, and office is tabulated below.  (A plant with three or
four mills will be considered to be equipped with two discharge conveyors
and two stationary compactors.)

                                TABLE N-4.

                     Total Plant Size - Square Feet

                                     Number of Mills
                             1         2         3        _4_
     One Shift

       Office & Workshop   1,000     1,000     1,500     1,500

       Employee Facilities   300       300       500       500

       Conveyor(s), Mill(s)
       and Compactor(s)    3,500     5,000     9,000    10,500

       Floor Storage-
       Refuse              2.500     5.000     7.500    10.000

          TOTAL            7,300    11,300    18,500    22,500

     Two Shifts

       Office & Workshop   1,000     1,000     1,500     1,500

       Employee Facilities   500       500       700       700

       Conveyor(s), Mill(s)
       and Compactor(s)    3,500     5,000     9,000    10,500

       Floor Storage-
       Refuse              4.300     8.500    12.700    17,000

          TOTAL            8,800    15,000    23,900    29,700
                                  420

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     The cost of foundations and building is computed by multiplying the
total space requirements in Table N-4 by $20 per square foot.  The entrance
road and site grading is computed on the basis of 20 percent of the founda-
tions and building construction costs.

                                TABLE N-5

      Cost of Foundations, Buildings, Entrance, Roads, and Grounds
                  For Combinations of Mills and Shifts
One Shift - Foundations and
            Buildings        $146,000  $226,000  $370,000  $450,000

          - Entrance Roads
            and Grounds        29,200    45,200    74.200    90.000

               TOTAL         $175,200  $271,200  $444,200  $540,000

Two Shift - Foundations and
            Buildings        $176,000  $300,000  $478,000  $594,000

          - Entrance, Roads
            and Grounds        35,200    60,000    95,600    11,900

               TOTAL         $211,200  $360,000  $573,600  $605,900

Labor Requirements and Costs

     The number of men needed to man the combination of mills and shifts
under consideration are shown in Table N-*6 as are the annual costs of labor.
Past experience at Madison has shown the need for proper supervision at all
levels of plant operation; thus, one supervisor is required for each case
shown.  Also included are tx
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      (5)  Welding Rods - 34 rods/set at $.50/rod;  or $17.00 per set of hammers.

           50 Ibs./liner set at $1.60/lb.;  or $80.00 per set of liners.
      (6)  Plant Supplies - $1,200 per one  mill shift; $500 additional for each
           mill; 50 percent additional for  second shift.

                                 TABLE N-6

                   Annual Labor Requirements and Costs

                                                    Number of Mills
 One Shift
   Supervisor

   Reduction Plant
   Foreman-Operator

   Reduction Plant
   Operator

   Public Works
   Maintenance Man

   Scale Man

      Total

 Two Shifts

   Supervisor

   Reduction Plant
   Foreman

   Reduction Plant
   Operator

   Public Works
   Maintenance Man

   Scale Man

      Total
Hourly    Annual
 Wage*     Wage

$6.26**  $13,000


$8.02    $16,660


$7.21    $14,990


$6.20    $12,890

$4.73    $ 9,840
$6.26    $13,000


$8.02    $16,660


$7.21    $14,990


$6.20    $12,890

$4.73    $ 9,840
111
111
122
223
— — 1
$ 70,430 $ 85^420 $108,150
111
222
234
223
- 1 2
$102,080 $126^910 $164,630
1
2
3
3
1
$139,800
1
4
4
3
2
$197,950
 *Including 30 percent fringe benefits and estimated overtime.

**0ther employees salary higher due to longevity pay program in City of Madison.
                                   422

-------
                                TABLE N-7

                     Annual Mill Maintenance Costs

                                        Number  of Mills
One Shift

(1) Hammers                  $ 2,330   $ 4,660    $  6,990    $  9,320

(2) Shafts                       580    1,160      1,740      2,320

(3) Wear Plates                1,600    3,860      5,760      7,680

(4) General Maintenance
      Mill(s)                  2,500    5,000      7,500    10,000

      Conveyor(s)                800    1,600      2,800      4,000

(5) Welding Rods                 370       740      1,110      1,480

(6) Plant Supplies             1.200    1.700      2.200      2.700

      Total                  $ 8,580   $18,720    $28,100    $37,500


Two Shifts
(1) Hammers                  $ 4,660   $ 9,320    $13,980    $18,640

(2) Shafts                     1,160    2,320      5,480      4,640

(3) Liners                     3,868    7,680     11,520     15,360

(4) General Maintenance
      Mill(s)                  4,500    9,000     13,500     18,000

      Conveyor(s)              1,440    2,800      5,040      7,200

(5) Welding Rods                 740    1,480      2,220      2,960

(6) Plant Supplies             1,800    2,550      3,300      4,050

      Total                  $18.160   $35.150    $53,040    $70,850
                                  423

-------
Power for Mills, Conveyors, and Stationary Compactor


     (1)  The maximum demand for each mill and conveyor system is 160 kw.

     (2)  The maximum demand for the compactor is 20 kw.

     (3)  The power consumption for each mill and conveyor system averages
          8.8 KWH/ton.

     (4)  The power consumption for each compactor is 16 KWH/hour.

     The monthly demand charge for one mill and conveyor system is:

        $2.00 for the first 10 kw, $2.00 per kw for each of
        the next 90 kw, and $1.00 per kw up to the 160 kw
        required for a total of $242

     The monthly demand charge for each additional mill and conveyor system is

        $1.00 x 160 kw - $160

     The monthly demand charge for each compactor is:

        $1.00/kw x 20 kw = $20


     The power consumption for one mill and conveyor system operating one
     shift is 8.8 KWH/ton x 14 tons/hour = 123.2 KWH/hr.  The monthly con-
     sumption then is 123.2 KWH/hour x 7 hours/day x 5 days/week x 4.0
     weeks/month = 17,250 KWH/month.  The monthly consumption cost for one
     mill operating one shift is:  0.026 x 500 KWH + $0.015 x 1000 KWH
     + $0.011 x 8500 KWH + $0.010 x 7,250 = $194.  The monthly consumption
     for all additional mill-shifts is $0.010 x 17,250 KWH = $172.  The
     monthly power consumption for each compactor working each shift is
     16 KWH/hr x 7 hrs./shift day x 5 days/week x 4.0 weeks/month = 2,240
     KWH/month.  The corresponding monthly consumption cost for each com-
     pactor shift is $0.080 x 2,240 KWH = $22.  The above listed power con-
     sumption costs are summarized as follows:

        The monthly power consumption cost for the first mill-shift
        is $194.
        The monthly power consumption for all additional mill-shifts
        is $172.
        The monthly power consumption cost for all compactor-shifts
        is $22.
                                  424

-------
                                TABLE N-8

                    Annual Power Costs for Mill(s)
                    Conveyor(s), and Compactors
                                            Number of Mills
                                            2         3
One Shift

Demand
  First Mill
  Each Addnl. Mill
  Each Compactor

Power Consumption
  First Mill-Shift
  Each Addnl. Mill-Shift
  Each Compactor-Shift

Total Monthly Charge
Annual Charge

Two Shifts

Demand
  Each Addnl. Mill
  Each Compactor

Power Consumption
  First Mill-Shift
  Each Addnl. Mill-Shift
  Each Compactor-Shift

Total Monthly Charge
Annual Charge

Lighting

     The consumption is to be proportioned on the basis of:

       (1)  The actual consumption in the reduction plant for one shift
            from July 1970 through December 1970, and for two shifts from
            January through June of 1972.

       (2)  The relative sizes of the buildings.

              The original building used for a one-shift operation was 60 ft,
     x 100 ft. = 6,000 sq. ft.  The expanded building used for the two-shift
     operation is approximately 13,000 sq. ft.  The ratio of floor space for
$242
160
20
194
172
22
$242
160
20
194
172
22
$
$
$5,
$
$
$8,
242
20
194
22
478
736
242
20
194
172
44
672
064
$ 242
160
20
194
172
22
$ 810
$9,720
$ 242
160
20
194
516
44
$ 1,176
$14,112
$ 242
320
40
194
344
44
$ 1,184
$14^208
$ 242
320
40
194
860
88
$ 1,744
$20,928
$ 242
480
40
194
516
44
$ 1,516
$18,192
$ 242
480
40
194
1,204
88
$ 2j_248
$26,976
                                   425

-------
1
7,300 =
6,000
8,800 -
13,000

1.22
.68
2
11,300 - 1.88
6,000
15,000 = 1.15
13,000
3
18,500 = 3.08
6,000
23,900 = 1.84
13,000
4
22,500 »
6,000
29,700 =
13,000

3.75
2.28
     the projected plants, as listed in Table N-9 to 6,000 sq. ft. or 13,000
     sq. ft. where applicable, is the relative size factor.  The relative
     sizes are:
                                TABLE N-9

                      Relative Sizes of Buildings

                     	 Number of Mills
                     1	    	;

One Shift


Two Shifts


     Table N-10 shows the actual consumption for the existing plant per month
studied, and the proportional usage based on relative building sizes, for one
shift.  Table  N-ll contains the same information as related to a two-shift operation.

                                TABLE N-10

            Actual and Proportioned Power Consumption (KWH)
                         For Lighting-One Shift

                    Actuj
    Month

July 1970

August 1970

September 1970

October 1970

November 1970*

December 1970*

   Average

*Figures adjusted - due  to construction
Actual KWH
Consumption
4,414
4,104
4,018
5,860
5,900
5,400


1
5,385
5,007
4,902
7,149
7,198
6,588
6,038
Number
2
8,298
7,715
7,554
11,017
9,109
10,152
8,974
of Mills
3
13,595
12,640
12,375
18,048
18,172
16,632
15,243

4
16,552
15,390
15,068
21,975
22,125
20,250
18,560
                                   426

-------
Actual KWH
Consumption
18,788
17,088
19,286
14,734
12,772
13,294


1
12,775
11,620
13,114
10,019
8,650
9,040
10,868
Number
2
21,606
19,651
22,179
16,944
14,687
15,288
18,393
of Mills
3
34,570
31,442
35,486
27,110
23,500
24,460
29,590

4
42,836
38,960
43,972
33,593
29,006
30,310
36,446
                                TABLE N-ll

           Actual and Proportional Power Consumption (KWH)
                        For Lighting-Two Shifts

                    Acti
     Month

January 1972

February 1972

March 1972

April 1972

May 1972

June 1972

   Average

     Based on the data given in Tables N-10 and N-ll a fairly good monthly averag.
of lighting power consumption for a one and two-shift operation can be obtained.
Table N-12 contains this average in relation to number of mills.


                                TABLE N-12

                Average Monthly Power Consumption  (KWH)
                   For Lighting One and Two Shifts

                                      Number of Mills
                         1          2          3          4

     One Shift         6,038      8,974     15,243     18,560

     Two Shift        10,868     18,393     29,590     36,446

     The demand charge would also be proportional to the size of the
building, but would be nearly constant throughout the year because the
charge is based on the high during the preceding 12 months.  The maximum
demand for the original one-shift plant was 20 kw and for the two-shift
plant 40 kw.  The maximum demand to be expected in any of the projected
plants is calculated by multiplying 20 kw or 40 kw whichever is applicable
by the relative building sizes as listed in Table N-9.  The maximum demand
is tabulated below.
                                  427

-------
                                TABLE N-13

                    Maximum Demand For Lighting - kw

                                   Number of Mills
1
24
27
2
38
46
3
62
74
_4
75
91
     One Shift

     Two Shifts

     The annual cost of lighting can be computed using the monthly average
consumption (KWH) and maximum demand as shown in Tables JSI-12 and N-13 and the
current utility rates.  Table N-14 contains the summary of lighting costs.

                                TABLE N-14

                Annual Cost of Lighting for Combinations
                          Of Mills and Shifts

                                       Number of Mills
                               1        234
     One Shift

       Demand

       Consumption

         Total

     Two Shifts

       Demand

       Consumption

         Total

Gas Heat

     The gas costs are computed in a similar manner as for lighting costs
because consumption is dependent on building size.  The actual consumption
is to be proportioned on the basis of:

     (1)  the actual consumption in the reduction plant for one shift
          from July 1970 through December 1970, and for two shifts from
          January through June of 1972, and

     (2)  the relative sizes of buildings.

     The relative building sizes have been previously computed and are
shown in Table N-4 . The actual gas consumption for the existing plant,
and the proportioned usage based on relative building size are shown in
the following two tables.
$

$1
$
1
$2
120
936
,056
432
,572
,004
$
1
$2
$
2
$3
696
,320
,016
888
,568
^456
$1,
2,
$3,
$1,
4,
$5,
272
148
420
560
044
604
$1
2
$4
$1
4
$6
,584
,592
,176
,968
,944
,912
                                  428

-------
               TABLE N-15

       Actual and Proportioned
  Gas Consumption (Heat) - One Shift
   Actual
Consumption
Number of Mills
Month
(Cu.ft.xlOO) 1
2
3
4
July 1970 00000
August 1970 00000
September 1970 30 37 56 92 112
October 1970 780 952 1,466 2,402 2,925
November 1970 3,420 4,173 6,430 10,533 12,825
December 1970 3,600 4,392 6,768 11,088 13,500
Average 1,590 2,450 4,020 4,890
The consumption for two shifts is listed in the following table. The
proportioned consumption was obtained by multiplying the relative building
size by actual consumption used in the expanded plant under two-shift operation
TABLE N-16
Actual and Proportioned
Gas Consumption (Heat) - Two Shifts
Actual
Consumption Number of Mills
Month (Cu.ft.xlOO) 1234
January 1972
February 1972 .
March 1972
April 1972
May 1972
June 1972
Average
8,679 5,900
8,297 5,640
5,124 3,480
1,983 1,350
618 420
540 370
2,860
9,980
9,540
5,890
2,280
710
620
4,840
15,970
15,270
9,430 .
3,650
1,140
990
7,740
19,790
18,920
11,680
4,520
1,410
1,230
9,590
                 429

-------
     Since only 6 months of good gas consumption data for a one and two
shift operation at Madison is available, only a rough estimate of gas costs
can be calculated.  This estimate is computed by doubling the total cost
figure obtained from the proportioned consumption as presented in Tables N-15
and N-16-.  The estimate is valid because each six-month's term studied con-
tains equal periods of warm and cold weather in relation to that period not
studied.  Table N-17 contains the projected yearly costs for gas as heat, based
on  natural gas rates in effect at the time of evaluation.

                                TABLE N-17

                       Annual Cost of Gas (Heat)
                         One and Two Shifts

                                 Number of Mills
                         1234
     One Shift        $1,746   $2,580   $4,104   $4,950
     Two Shifts       $2,976   $4,902   $7,722   $9,516

Water and Sewer

     The usage is proportional to the tonnage milled, and has been found
to cost $0.002 per ton.  Rather than going through the tedious procedure
used for estimating lighting and gas costs, the water and sewer costs are
estimated by multiplying the annual tonnage by $0.002 per ton..  This method
is felt to be valid because the cost per ton was nearly constant throughout
the periods tested, and because the volume consumed is low enough that the
same utility rate applies.

                                TABLE N-18

                  Annual Water Costs for Combinations
                          Of Mills and Shifts
                   (Based on Cost of $0.002 Per Ton)

                                 Number of Mills
                        1234
     One Shift         $49       $ 98     $147      $196
     Two Shifts        $98       $196     $294      $392

Tractor and Transfer Trailer Requirements

     The number of trailers and tractors required is computed below.  Based
on actual data a 70-yard trailer loaded with 15 tons of milled refuse would
have a density of 430 Ibs. per cubic yard.  Each trailer is limited to
15 tons because of State highway regulations.  Past experience has shown
that switching and unloading of each trailer averages 30 minutes when the
plant is located on the fill site.  At a mill production of 14 tons per hour
one mill will fill one trailer in 64 minutes.  Two mills operating at 14 tons
per hour each will fill one trailer in 32 minutes.  Thus a one mill plant
will need a minimum of two trailers.  A two mill plant could also function
with only two trailers; but would be advised to have three to minimize pro-
duction down time because of trailer breakdowns or delays in the switching-
unloading process.  Both a one mill arid two mill plant would require only
one tractor to pull the trailers.  The above data would be applicable to a
one shift: or two shift operation.
                                  430

-------
     As mentioned previously any three or four mill plant should contain
two stationary compactors.  Taking this and the above data into considera-
tion, a three mill plant would require four trailers and a four mill plant
five trailers.  Each three and four mill plant should be equipped with a
minimum of two tractors.  Table N-19 summarizes the above data.


                                TABLE N-19

                    Tractor and Trailer Requirements

                                     Number of Mills
                             1        2        3        4

     One_Shift

       Tractors              1123
       Trailers              2345

     Two Shift

       Tractors              1123
       Trailers              2345

Annual Tractor and Transfer Trailer Operation and Maintenance Costs

     Maintenance on the tractors and trailers is charged on a mileage basis;
$0.20/mi. for tractors and $0.25/mi. for trailers.  To compute maintenance
costs it is first necessary to determine the number of loads taken to the
fill site; based on the information given above.

                                TABLE N-20

                        Number of Loads Per Day

                                   Number of Mills
                             1        2        3        4

     One Shift               7       14       21       28

     Two Shifts             14       28       42       56

     The annual operating cost for the tractors can be computed as follows:
multiply the number of daily trips by round trip distance traveled, 0.5 mile
in Madison, x $0.20/mi. x 245 operating days/year.  The computation for the
trailers is the same except $0.25/mi. is used instead of $0.20/mi.  The ap-
propriate annual cost for tractor and trailer maintenance is shown in Table N-21.
                                   431

-------
                                TABLE N-21

                 Annual Operation and Maintenance Cost
         For Tractor and Transfer Trailer Operation Per Unit

                                    Number of Mills
                              1        2        3        4
     One Shift

       Tractors             $172    $  344   $  516   $  688
       Trailers              215	430	645	860

          Total             $387    $  774   $1.161   $1.548

     Two Shifts

       Tractors             $344    $  688   $1,032   $1,376
       Trailers              430	860    1.290    1,720
          Total             $774    $1.548   $2.322   $3.096


Annual Stationary Compactor Maintenance Costs

     Past studies conducted at the Madison plant have revealed that on the
average, stationary compactor maintenance has cost approximately $0.02/ton,
based on a one shift operation.  It would be reasonable to assume that a
50 percent increase in costs would be experienced when the machinery is
operated on a two shift basis.  Using these figures as a guide the annual
operating costs for the combination of shifts and mills being studied is
shown in Table N-22.  It should be reemphasized that all three and four mill
plants are designed for two compactors.

                                TABLE N-22

             Annual Stationary Compactor Maintenance Costs

                                    Number of Mills
                             1        2        3        4
     One Shift

       First Compactor    $  480   $  960   $  960   $  960
       Second Compactor    __;;	-	480	960

          Total           $  480   $  960   $1.440   $1.920

     Second Shift

       First Compactor    $1,440   $2,880   $2,880   $2,880
       Second Compactor    _=	-	1,440    2.880

          Total           $1.440   $2.880   $4.320   $5.760
                                  432

-------
  Annual Front End Loader Operation and Maintenance

       For one and two mill operations a small end loader would be sufficient
  to handle all tonnage processed.  For a three and four mill plant, a medium
  range end loader would be required.  The operation and maintenance of both
  pieces of equipment is assumed to cost $4.25/hr.  The end loader will operate
  5 hours and 10 hours per day for a one mill, one shift and one mill, two shift
  operation, respectively.  The same piece of machinery will operate 6 hours and
  12 hours per day for a two mill, one shift and two mill, two shift operation,
  respectively.  The end loader will operate 7 and 14 hours for a three mill,
  one and two shift operation, and 7 and 14 hours for a four mill, one and two
  shift operation, respectively.

                                  TABLE N-23

                   Annual Operation and Maintenance Costs
                            For Front End Loader

                                      Number of Mills
                               1         2         3        _4_

       One Shift           $ 5,205   $ 6,246   $ 7,287   $ 7,287
       Two Shifts          $10,410   $12,492   $14,575   $14,575

  Amortization*

       Amortization data and annual costs are listed below for all depreciable
  items.

  Building

       Amortize over 20 years at 4.0 percent interest, salvage estimated at
  3.0 percent of original cost as contained in Table N-5.
  *Amortization or annual cost is calculated on the basis of the following
  equation: *
                     A.C. = (P-L) (CRF) - Li
  where              A.C. = annual cost
                       P  = initial investment
                       L  = salvage value
                     CRF  = capital recovery factor
                      i%  = interest rate
                       N  - rated full life

  The interest rate, i%, used in the computations, is a function of the
  expenditure involved; i.e., short term notes or long term bonds.  The
  City of Madison usually funds large expenditures by long term bonds.
  The interest rates in effect at the time of writing are 4.0 percent on
  long term bonds.
yGrant, E.  L.,  and W.  G.  Ireson.   Principles of  engineering economy.
      4th  Ed.   New York, The Roland Press  Company,  1964.   574 p.
                                    433

-------
     One Shift

     Two Shifts
                                TABLE N-24.

                 Annual Cost of Foundation and Building

                                          Number of Mills
                                123
$12,720   $19,690   $32,250   $39,200

$15,330   $26,130   $41,640   $43,980
                                TABLE N-25

                     Amortization* Data and Annual Costs

                                       Depre-    Int.
                             Original  ciation  Rate, Salvage Annual
Cost Item
Scale
Front Endloader
Michigan
Case
Grinder and Conveyor (ea)
Stationary Compactor (ea)
Trailers (ea)
Tractor (ea)
Annual Projected Operating
For Combinations of Mills
Cost Rate-Yrs. %




$15

$32
$22
$140
$
$
$
22
19
15
,000

,000
,000
,000
,000
,000
,000
20

12
12
15
15
12
15
and Amortization
and
4

4
4
4
4
4
4
Costs
.0

.0
.0
.0
.0
.0
.0

Value
$

$
$
$
$
$
$

1,000

5,000
3,000
4,000
1,000
750
1,500

Cost
$

$
$
1

3
2
$12
$
$
$

1
1
1

,,076

,089
,153
,400
,930
,982
,275

Shifts
     Tables N-26 and N-27 summarize all costs of operating the various
sized plants and the amortization rates of each.
*NOTE:  This is not a surplus fund for replacement of equipment, but
 reflects municipal approaches for amortization.
                                  434

-------
                                TABLE  N-26

           Annual Cost for One Through Four Mills - One Shift

                                        Number of Mills
                                123
Labor                       $ 70,430  $ 85,420   $108,150   $139,800

Mill Maintenance               8,580    18,720    28,100     37,500

Power - Mills, Conveyors,
  and Compactors               5,740     9,720    14,210     18,190

Lighting                       1,060     2,020      3,420     4,180

Gas (Heat)                     1,750     2,580      4,100     4,950

Water                             50       100       150       200

Tractor and Trailer Operations
  and Maintenance                 390       770      1,160     1,550

Front End Loader Operation
  and Maintenance              5,210     6,250      7,290     7,290

Compactor Maintenance             480	960      1,440     1,920

 Subtotal, Operating Costs  $ 93.690  $126.540   $167,920   $215,580

Amort i zat ion

Building                    $ 12,720  $ 19,690   $ 32,250   $  39,200

Scale                          1,080     1,080      1,080     1,080

Front End Loader               2,150     2,150      4,090     3,090

Mill(s) and Conveyors         12,400    24,800    37,200     49,600

Stationary Compactor(s)        1,930     1,930      3,860     3,860

Trailers                       3,960     5,940      7,960     9,940

Tractor(s)                     1.280     1,280      2.560     3,840

  Subtotal, Amortization    $ 35.520  $ 56,870   $ 88,000   $110,610

    Total Annual Cost       $129,210  $183.410   $255,920   $326,190
                                  435

-------
                                TABLE  N-27

          Annual Costs for One Through Four Mills - Two Shifts


                                         Number of Mills
                                1         2         3         4

Labor                       $102,080   $126,910  $164,630  $197,950

Mill Maintenance              18,160    35,150    53,040    70,850

Power - Mills, Conveyors,
  and Compactors               8,060    14,110    20,930    26,980

Lighting                       2,000     3,460     5,610     6,910

Gas (Heat)                     2,980     4,900     7,720     9,520

Water                            100       200       290       390

Tractor and Trailer Operation
  and Maintenance                780     1,550     2,320     3,100

Front End Loader Operation
  and Maintenance             10,410    12,490    14,580    14,580

Compactor Maintenance          1,440	2.880     4,320     5,760

  Subtotal Operating Costs  $146.010   $201,650  $273,440  $336,040

Amortization

Building                    $ 15,330   $ 26,130  $ 41,640  $ 43,980

Scale                          1,080     1,080     1,080     1,080

Front End Loader               2,150     2,150     3,090     3,090

Mill(s) and Conveyors         12,400    24,800    37,200    49,600

Compactor(s)                   1,930     1,930     3,860     3,860

Trailers                       3,960     5,940     7,960     9,940

Tractor(s)                     1.280     1.280     2,560     3.840

  Subtotal Amortization     $ 38.130   $ 63,310  $ 97,390  $115.390

    Total Annual Cost       $184,140   $264,960  $370,830  $451.430
                                   436

-------
Landfilling Cost Projections

     Landfill cost projections will be based on the tonnages processed by
each combination of mills and shifts discussed in the previous section.
Costs will include labor for compaction, machine operation and maintenance,
and equipment amortization.  Land costs are excluded.  No charges are pro-
jected for cover material since no daily cover is used when landfilling milled
refuse at Madison.

Labor and Equipment Requirements and Costs:

     Projections based on data obtained at Madison reveal that one operator
utilizing a steel wheeled compactor can efficiently handle 300 to 360 tons of
milled refuse per day.  Based on this projection and the assumption that
landfills adjacent to the projected plant operations x^ill be operated only
one 8-hour shift per day, the following labor and equipment requirements
are made.

                                TABLE N-28*

                        Daily Landfill Labor and
                         Equipment Requirements

                                          Number of Mills
                                 1        2        3        4

One Shift

     Tons per day              100      200      300      400

     Man Shifts                  1111

     Trash Pak(s)                1        1        1        1

Two Shifts

     Tons per day              200      400      600      800

     Man Shifts                  1122

     Trash Pak(s)                1122
                                  437

-------
                                TABLE N- 29

                Annual Labor Costs - Landfill Operations

                                         Number of Mills
                              Annual*
              Employee         Wage     1       _2        3        4

             Operator       $13,000  $13,000  $13,000  $13,000  $13,000
             Site Control    11,300    5,650    5,650   11,300   11,300
One Shift    Supervisor      15,100    3.800    3,800    7.500    7.500

               TOTAL                 $22,450  $22,450  $31,800  $31,800

             Operator       $13,000  $13,000  $13,000  $26,000  $26,000
             Site Control    11,300    5,650   11,300   11,300   11,300
Two Shift    Supervisor      15,100    3,800    7.500   15,100   15,100

               TOTAL                 $22,450  $31,800  $52,400  $52,400

*Includes 30% fringe benefits excluding overtime.

     To compute equipment operating and maintenance costs it is assumed
that the landfill compactor will operate a minimum of 2 hours per 8 hour
day and a maximum of 6 hours per 8 hour day at the rate of spreading and
compacting 45 to 65 tons of milled refuse per hour.  Operation and maintenance
for landfill equipment are charged at the rate of $6.25/hour of operation.
Compactor amortization is charged at the rate of $5,960 per year for an
initial investment of $45,000 and an 8-year equipment life.


                                TABLE N-30

                Annual Operating and Maintenance Costs -
                           Landfill Equipment

                                         Number of Mills
                               1        2        3        4
One Shift

     Hours                     990    1,225    1,470    1,715
     Compactor Cost         $6,130  $ 7,660  $ 9,190  $10,720
     Misc. Equipment Cost      610	770	920    1.070

       Total Cost           $6,740  $ 8,430  $10,110  $11,790

Two Shifts

     Hours                   1,225    1,715    2,940    3,430
     Compactor Cost         $7,660  $10,720  $18,380  $21,440
     Misc. Equipment Cost      770    1,070    1.840    2,140

       Total Cost           $8,430  $11,790  $20,220  $23,580
                                   438

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Total Annual Projected Landfilling Costs:


                                TABLE N-31

                   Annual Projected Landfilling Costs

                                           Number of Mills

     Landfill                    1        2        3        4

One Shift

     Labor                  $22,450  $22,450  $31,800  $31,800
     Compaction Equipment -
       Operation and
       Maintenance            6.740    8.430   10t110   11.790

Subtotal Operating Costs    $29.190  $30,880  $41,910  $43,590

     Depreciation -
       Compaction Equipment $ 5.960  $ 5.960  $11,920  $11,920

Total Operating Costs       $35,150  $36.840  $53,830  $55.510

Two Shifts

     Labor                  $22,450  $31,800  $52,400  $52,400
     Compaction Equipment -
       Operation and
       Maintenance            8.430   11.790   20,220   23,580

Subtotal Operating Costs    $30,880  $43.590  $72.620  $75,980

     Depreciation -
       Compaction Equipment   5,960    5,960   11,920   11,920

Total Operating Costs       $36.840  $49.550  $84.540  $87,900
                                  439

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Summary of Annual Milling and Landfilling Costs


                                TABLE N-32

 Annual Cost of Milling, Milled Refuse Transfer System and Landfilling
                               One Shift

                                            Number of Mills
                               1234
Annual Tonnage               24,500    49,000    73,500    98,000

Reduction Plant & Transfer
  Operating Costs          $ 93,690  $126,540  $167,920  $215,580
  Amortization               35.520    56,870    88,000   110.610

Total Reduction Plant      $129,210  $183,410  $255,920  $326,190
Cost Per Ton*              $5.27     $3.74     $3.48     $3.33

Millfill
  Operation Costs          $ 29,190  $ 30,880  $ 41,910  $ 43,590
  Amortization                5.960     5.960    11,920    11.920

Total Landfill             $ 35,150  $ 36,840  $ 53,830  $ 55,510

Cost Per Ton**             $1.43     $0.75     $0.73     $0.57

TOTAL ALL OPERATIONS       $164,360  $220,250  $309,750  $381,700

COST PER TON               $6.70     $4.49     $4.21     $3.90
 *Cost includes amortization, labor, operating, and milled refuse haul to
  landfill less than one-half mile round-trip distance.  Land cost excluded,

**Millfill cost includes labor and equipment costs with amortization.  Land
  cost and site preparation costs are excluded.
                                   440

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V
                                           TABLE  N-33

            Annual Cost of Milling, Milled Refuse Transfer  System and Landfilling -
                                         Two  Shifts
                                                          Number of Mills
                                               1          2          3         4

                                            49,000    98,000    147,000   196,000
Annual Tonnage

Reduction Plant & Transfer
  Operating Costs
  Amortization

Total Reduction Plant

Cost Per Ton*

Millfill
  Operating Costs
  Amortization

Total Landfill

Cost Per Ton

TOTAL ALL OPERATIONS

COST PER TON**
                                           $146,010   $201,650   $273,440   $336,040
                                             38.130    63,310    97.390   115.390

                                           $184,140   $264,960   $370,830   $451,430

                                           $3.75      $2.70      $2.52      $2.30


                                           $  30,880   $ 43,640   $ 72,620   $ 75,980
                                              5,960     5.960    11.920    11,920

                                           $  36,840   $ 49,600   $ 84,540   $ 87,900

                                           $0.75      $0.50      $0.57      $0.45

                                           $220,980   $314,560   $455,370   $539,330

                                           $4.50      $3.20      $3.09      $2.75
            *Cost includes amortization, labor, operating, and milled refuse haul to
             landfill less than one-half mile round-trip distance.  Land cost excluded,

           **Millfill cost includes labor and equipment costs with amortization.  Land
             cost and site preparation costs are excluded.
                                             441

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jO - Composition of Madison's  Solid Waste

      This is a report on work done by the Bureau of Solid Waste
Management to determine the composition of Madison's solid wastes.
COMPOSITION OF SOLID WASTES: MADISON, WISCONSIN  (TSR/01.15/9)

      During the week of November 4,  1968, solid waste influent
to the Madison, Wisconsin, Refuse Reduction Plant was sampled
and categorized. This study was conducted by personnel of the
Solid Wastes Program as a training exercise for new engineers and
to provide needed data to the demonstration project. The  results
of the separation were submitted to the City of Madison.

      Residential solid wastes were sampled on November 5,  6 and
7, 1968.  Incoming packer trucks were directed to the sampling
area, and the driver was instructed to lift the tailgate until enough
wastes had been dumped. Previous experience had shown that
200-lb. samples would be sufficient if more than eight separations
were made. The wastes dumped from the trucks would then be randomly
subdivided until the resulting sample was judged to be 200 Ibs.
or more.  Four separations were made on November 5 and on  November
6. Two separations were made on November 7.  Usual practice
was to take each sample from a different truck.

      After the samples were selected, they were hand sorted into
the following components:

      Food Wastes                    Wood
      Garden Wastes                  Metals
      Paper Products                 Glass and Ceramics
      Plastics , Rubber and Leather    Rocks , Dirt, Ashes , etc.
      Textiles

The percentage of each component was  then determined on as as-
received  or wet basis.

      Moisture content determinations were made on half of the
samples ,  the first and fourth samples the first two days and the
first sample  on the third day.  This was done by combining one
percent of the weight of the food wastes, paper products,  and garden
                            442

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wastes components for a particular sample.  The moisture contents
determined for these portions were then adjusted to reflect the mois-
ture contents of the total samples.

      The minimum, maximum,  and average percentages of each
component, by weight, are given below.
                         TABLE 0 -i

  Range of Compositions of Madison's Solid Wastes  (Wet Basis)
by Federal Solid
Wastes Program
(Nov.
1968)


Food Wastes
Garden Wastes
Paper Products
Plastics, Rubber, Leather
Textiles
Wood
Metals
Glass and Ceramics
Rocks, Dirt, Ashes, etc.
Minimum
4.4
0.0
35.1
0.3
0.1
0.0
5.0
4.4
0.6
Maximum Average
28.9
31.1
53.2
3.7
7.8
2.6
14.5
17.6
17.6
15.3
13.8
42.4
1.8
1.6
1.1
6.7
10.1
7.2
Note:  The moisture content varied from 30 to 48 percent,
      with an average of 37 percent.
                               443

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 JP- List of European Sites Visited and Persons Interviewed

                            SITES
      Location

 UNITED KINGDOM

 1.  Bishopbriggs
 2.  Bathgate
 3.  Brackley
 4.  Chesterfield
 5.  Cringle Dock - Greater
    London Council
 6.  East Grinstead
 7.  Horsham
 8.  Leamington Spa
 9.  Scunthorpe
10.  Woking
11.  Worthing
Mill Used At Facility
British Jeffery Diamond
Volund - John Thompson
Gondard
Buhler

British Jeffery Diamond
Tollemache
Tollemache
Gondard
British Jeffery Diamond
Vicker Seer drum
British Jeffery Diamond
 FRANCE

 1.  Elbeuf                     Gondard
 2.  Louvier                    Gondard
 3.  Meaux                     Gondard
 4.  St.  Etienne de Vouvray      Gondard
 5.  St.  Quentin                 Gondard
 SWITZERLAND

 1.  Aarau
 2.  Biel
 3.  Flims
Landfill
Buhler
Buhler
 GERMANY

 1.  Russelsheim
 2.  Hockheim
 3.  Wiesbaden
Gondard
Landfill
Gondard
                               444

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                         INTERVIEWS

      Name                    Affiliation

1.  E. R. Green                Dept. of the Environment, United Kingdom
2.  D.Parkinson               British Jeffery Diamond, Ltd.
3.  Serge Pollet                Rural des Eaux et Forets
4.  Guy F. Robinson           Tollemache Composting Systems,  Ltd.
5.  Jacques Sigwalt            Gondard
6.  Dietegen Stickelberger      World Health Organization
7.  J. Sumner                 Dept. of the Environment, United Kingdom
                                                   a.
                              445

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-»ATF

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