United States
Environmental Protection
Agency
Water Engineering Research
Laboratory
Cincinnati OH 45268
Technology Transfer
EPA/625/6-85/010
vvEPA
Handbook
Estimating Sludge
Management Costs
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NOTICE
This document has been reviewed in accordance with the U.S. Environmental
Protection Agency's peer and administrative review policies and approved for
publication. Mention of trade names or commercial products does not consti-
tute endorsement or recommendation for use.
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EPA/625/6-85/010
HANDBOOK
ESTIMATING SLUDGE MANAGEMENT COSTS
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development.
Water Engineering Research Laboratory
Cincinnati, Ohio 45268
October 1985
Published by
U.S. ENVIRONMENTAL PROTECTION AGENCY
Center for Environmental Research Information
Cincinnati, Ohio 45268
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FOREWORD
The formation of the U.S. Environmental Protection Agency (EPA) marked a
new era of environmental awareness in America. This Agency's goals are
national in scope and encompass broad responsibilities in the areas of air and
water pollution, solid and hazardous wastes, pesticides and toxic substances,
and radiation. A vital part of EPA's national pollution control effort is the
constant development and dissemination of new information.
The purpose of this Handbook is to provide information on estimating
costs for management of the sludge residue that results from municipal waste-
water treatment. The cost for siudge management represents as much as hal f of
the total cost of wastewater treatment.
The information in this Handbook should make it possible to obtain rapid
cost comparisons between different sludge management alternatives. This, in
turn, should result in choosing more cost-effective combinations of processes
and help decrease the nationwide cost of sludge management.
At some time in the future, we may consider updating this Handbook if
interest seems to justify such an effort. With that goal in mind, comments
that would aid in issuing a revised and improved version are earnestly solic-
ited.
We sincerely hope that this document will be of value to those interested
in municipal sludge management.
n
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ABSTRACT
This manual provides preliminary cost estimating curves, covering both
capital costs and annual operating and maintenance (O&M) costs, for commonly
used processes in municipal wastewater sludge treatment, storage, transport,
use, or disposal. In addition, annual O&M component curves, which provide
additional user flexibility, are also included. Curves are based on the cost
algorithms contained in Appendix A. The processes can be readily arranged
into various sludge management chains and preliminary costs estimated for each
sludge management chain to be evaluated. Costs presented are based on the
last quarter of 1984, and can be updated to later years by use of appropriate
cost indexes.
An annotated bibliography of selected literature containing sludge man-
agement cost estimating information is included in Appendix B. Appendix C
provides commonly used English to metric conversion factors.
The cost curves provided generally cover a range up to 100 million gal-
lons of sludge per year, which is roughly equivalent to a wastewater treatment
plant capacity of at least 50 mgd. The range selected includes plant sizes
where it was considered that supplemental cost information might be the most
useful. By using the cost curves, the user may obtain approximate capital and
annual O&M costs rapidly. Where applicable, a family of curves is presented
showing cost differentials as a ^function of a significant sludge quality vari-
able (e.g., sludge suspended solids) or operational variable (e.g., dry solids
application rate).
The cost estimating algorithms, on the other hand, present a logical
series of calculations for inputting site-specific data for deriving base cap-
ital and base annual operation and maintenance costs.
This report was submitted in fulfillment of Contracts 68-03-3017 and 68-
01-6621 by SCS Engineers, under sponsorship of the U.S. Environmental Protec-
tion Agency. '
iii
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ACKNOWLEDGEMENTS
This handbook was prepared for the U.S. Environmental Protection Agency
(EPA) by SCS Engineers, Long Beach, California, under a direct contract, and
under a subcontract with ICF, Inc., Washington, O.C.
Dr. Joseph B. Parrel! and Dr. Harry E. Bostian of EPA's WERL* were
responsible for overall project direction. Other EPA staff contributing to
project management were R. V. Villiers, WERL, and Orville E. Macomber and Dr.
James E. Smith, CERI.
EPA staff who provided review comments on drafts of the handbook were the
foil owing:
Robert K. Bastian, OMPC.
Dr. Harry E. Bostian, WERL.
Dr. Carl A. Brunner, WERL.
Ben Chen, Region IV.
A!den 6. Christiansen, WERL.
Dr. Robert M. Clark, WERL.
Richard G. Eilers, WERL.
Dr. Joseph B. Parrel 1.
Gilbert M. Gigliotti, CERI.
Dr. James A. Heidman, WERL.
Orville E. Macomber, CERI.
Steven Poloncsik, Region V.
Dr. Lewis A. Rossman, WERL.
Dr. James A. Ryan, WERL.
Dr. James E. Smith, CERI.
Charles S. Spooner, OWP.
Dr. John M. Walker, OMPC.
James Wheeler, OMPC.
were:
Other individuals who provided review comments on drafts of the handbook
Gordon L. Culp, Gulp, Wesner, Gulp, Inc., Consulting Engineers.
Dr. Richard I. Dick, Cornell University.
Dr. Cecil Lue-Hing, Chicago MSD.
J. Robert Nicholson, Zimpro, Inc.
Sherwood C. Reed, U.S. Army Corps of Engineers.
Thomas K. Walsh, Metcalf and Eddy, Inc.
EPA organizational abbreviations are as follows:
WERL - Water Engineering Research Laboratory, Cincinnati, Ohio.
CERI - Center for Environmental Research Information, Cincinnati, Ohio.
OMPC - Office of Municipal Pollution Control, Washington, D.C.
OWP - Office of Water Policy, Washington, D.C.
IV
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SCS Engineers staff making major contributions were:
Kenneth V. LaConde, Project Director.
Curtis J. Schmidt, Senior Project Engineer.
Julio A. Nuno, Project; Engineer.
Richard Taylor, Computer Programming.
Steven R. Davidson, Computer Programming.
II knur Erbas, Researcher.
Robert W. Black, Word Processing.
Jane E. Humphrey, Word; Processing.
K. J. Lee, Graphics.
Other major contributors were:
* Dr. Robert Gumerman and Bruce Burris, Culp, Wesner, Gulp, Inc., Con-
sulting Engineers, Santa Ana, California.
• Ms. Berrin Tansel , University of Wisconsin, CAPDET Programming.
i
* Robert A. Witzgall, Gregory R. Heath, Jeffrey R. Pinnette, and Elliot
Crafts, Metcal f & Eddy, Inc., Wakefield, Massachusetts.
Contract Administrator for ICF, Inc., Washington, D.C., was Ms, Nan F.
Darack, Contracts Supervisor. |
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CONTENTS
Section Page
Foreword ii
Abstract iii
Acknowledgements . iv
Contents vi
Figures ix
Tables xix
1 Introduction
1.1 General 1
1.2 Project Development History '.".'. 2
1.3 Development of the Algorithms and Cost Curves! .* . . . 3
1.4 Relative Accuracy of the Costs Presented 5
1.5 Other Sludge Management Processes Not Included in
This Manual 6
1.6 Other Sludge Management Process Cost Information in
the Technical Literature 7
1.7 English to Metric Conversion Factors 8
1.8 References 8
2 User's Guide
2.1 General 9
2.2 Developing the Sludge Management Process Chain .... 9
2.3 Developing the Mass Balance of Sludge Volume and
Sludge Concentration Entering and Leaving Each Process 9
2.4 Mass Balance Example 13
2.5 Importance of Assumptions Listed on Cost Curves. ... 27
2.6 Total Project Cost 29
2.7 Calculating Cost Per Dry Ton. 35
2.8 Example Using Cost Curves 35
2.9 References 37
3 Raw Sludge Thickening Curves
3.1 Introduction 42
3.2 Gravity Thickening. . . 42
3,3 Flotation Thickening 46
vi
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CONTENTS (continued)
Section
Page
8
Sludge Stabil ization Curves
4.1 Introduction 50
4.2 Anaerobic Digestion 50
4.3 Aerobic Digestion 54
4.4 Lime Stabilization 54
4.5 Thermal Treatment 54
Sludge Dewatering Curves
5.1 Introduction 70
5.2 Dewatered Sludge Cake Generated by Various
Dewatering Devices 70
5.3 Chemical Conditioning " 71
5.4 Centrifuge Dewatering 71
5.5 Belt Filter Dewatering 71
5.6 Recessed Plate Filter Press Dewatering 71
5.7 Vacuum Filter. 81
5.8 Sludge Drying Beds 81
Sludge Chemical Conditioning Curves
6.1 Introduction 90
6.2 Use of Chemical Conditioning 90
6.3 Chemical Conditioning Using Lime 90
6.4 Chemical Conditioning Using Ferric Chloride 100
6.5 Chemical Conditioning Using Polymer Addition 100
Sludge Incineration Curves
!
7.1 Introduction 119
7.2 Fluidized Bed Incineration . 120
7.3 Multiple Hearth Incineration 120
Sludge Composting Curves
8.1 Introduction .\ 129
8.2 Windrow Composting 129
8.3 Aerated Static Pile Composting 130
8.4 Land Cost Adjustment 130
Sludge Transport Curves
9.1 Introduction . ' 144
9.2 Truck Hauling 144
9.3 Rail Hauling 152
9.4 Barge Hauling 152
9.5 Pipeline Transport 152
vii
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CONTENTS (continued)
Section
10
Page
Sludge Application to Land Curves
10.1 Introduction 177
10.2 Land Application to Cropland 177
10.3 Sludge Application to Marginal Land for Land
Reclamation 183
10.4 Land Application to Forest Land Sites 183
10.5 Land Application to Dedicated Disposal Site 196
10.6 Land Disposal to Sludge Landfill 196
10.7 Adjustment of Curve Costs for Land Costs
Different from Those Assumed 196
10.8 Adjustment of Curve Costs to Include Clearing,
Grading, and Lime Addition 211
11 Sludge Storage Curves
11.1 Introduction 214
11.2 Facultative Lagoon Storage 214
11.3 Enclosed Tank Storage 218
11.4 Unconfined Pile Storage 218
11.5 Land Cost Adjustment 218
Appendix A - Cost Algorithms 229
Appendix B - Annotated Bibliography of Sources of Cost
Information in the Technical Literature . ., 519
Appendix C - U.S. Customary to Metric Conversion Factors 534
viii
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FIGURES
Number Page
2-1 Sludge Management Processes Included in This Manual 10
2-2 Example Flowsheet for Sludge Treatment Process Chain Showing
Flow Streams Entering and Leaving Each Sludge Management
Process 14
3-1 Base Capital Cost of Gravity Thickening as a Function of Annual
Volume and Raw Sludge Solids Concentration . 43
3-2 Base Annual Q&M Cost of Gravity Thickening as a Function of
Annual Volume and Raw Sludge Solids Concentration 44
3-3 Annual O&M Requirements for Gravity Thickening as a Function
of Annual Volume and Raw Sludge Solids Concentration 45
3-4 Base Capital Cost of Dissolved Air Flotation Thickening as a
Function of Annual Volume and Raw Sludge Solids Concentration . . 47
3-5 Base Annual O&M Cost of Dissolved Air Flotation Thickening as
a Function of Annual Volume and Raw Sludge Solids Concentration . 48
3-6 Annual O&M Requirements for Flotation Thickening as a Function
of Annual Volume and Sludge Solids Concentration 49
4-1 Base Capital Cost of Anaerobic Digestion as a Function of
Annual Volume and Sludge Solids Concentration 51
4-2 Base Annual O&M Cost of Anaerobic Digestion as a Function of
Annual Volume and Sludge Solids Concentration 52
4-3 Annual O&M Requirements for Anaerobic Digestion as a Function
of Annual Volume and Sludge Solids Concentration 53
4-4 Capital Cost of Aerobic Digestion Using Mechanical Aerators
as a Function of Annual Volume and Sludge Solids Concentration- . 55
4-5 Base Annual O&M Cost of Aerobic Digestion Using Mechanical
Aerators as a Function of Annual Volume and Sludge Solids
Concentration . . . 56
4-6 Annual O&M Requirements for Aerobic Digestion Using Mechanical
Aerators as a Function of Annual Volume and Sludge Solids
Concentration . . . . ' 57
ix
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FIGURES (continued)
Number Page
4-7 Base Capital Cost of Aerobic Digestion Using Diffused Aeration
as a Function of Annual Volume and Sludge Solids Concentration. . 58
4-8 Base Annual O&M Cost of Aerobic Digestion Using Diffused
Aeration as a Function of Annual Volume and Sludge Solids
Concentration 59
4-9 Annual O&M Requirements for Aerobic Digestion Using Diffused
Aeration as a Function of Annual Volume and Sludge Solids
Concentration 60
4-10 Base Capital Cost of Lime Stabilization as a Function of
Annual Volume and Sludge Solids Concentration . . .' 61
4-11 Base Annual O&M Cost of Lime Stabilization as a Function of
Annual Volume and Sludge Solids Concentration 62
4-12 Annual O&M Requirements for Lime Stabilization as a Function
of Annual Volume and Sludge Solids Concentration 63
4-13 Base Capital Cost of Sludge Thermal Conditioning as a Function
of Annual Vol ume 65
4-14 Base Annual O&M Cost of Sludge Thermal Conditioning as a
Function of Annual Volume 66
4-15 Annual O&M Requirements for Sludge Thermal Conditioning as a
Function of Annual Volume 67
5-1 Base Capital Cost of Centrifuge Dewatering as a Function of
Annual Volume and Sludge Solids Concentration 72
5-2 Base Annual O&M Cost of Centrifuge Dewatering as a Function
of Annual Volume and Sludge Solids Concentration 73
5-3 Annual O&M Requirements for Centrifuge Dewatering as a Function
of Annual Volume and Sludge Solids Concentration 74
5-4 Base Capital Cost of Belt Filter Press Dewatering as a Function
of Annual Volume and Sludge Solids Concentration 75
5-5 Base Annual O&M Cost of Belt Filter Press Dewatering as a
Function of Annual Volume and Sludge Solids Concentration .... 76
5-6 Annual O&M Requirements for Belt Filter Press Dewatering as a
Function of Annual Volume and Sludge Solids Concentration .... 77
5-7 Base Capital Cost of Recessed Plate Filter Press Dewatering as
a Function of Annual Volume and Sludge Solids Concentration ... 78
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FIGURES (continued)
Number, ' Page
i
5-8 Base Annual O&M Cost of Recessed Plate Filter Press Dewatering
as a Function of Annual Volume and Sludge Solids Concentration. . 79
5-9 Annual O&M Requirements for Recessed Plate Filter Press
Dewatering as a Function of Annual Volume and Sludge Solids
Concentration . . . . ; 80
5-10 Base Capital Cost of Vacuum Filter Dewatering as a Function of
Annual Volume and Sludge Solids Concentration 82
5-11 Base Annual O&M Cost of Vacuum Filter Dewatering as a Function
of Annual Volume and Sludge Solids Concentration 83
5-12 Annual O&M Requirements for Vacuum Filter Dewatering as a
Function of Annual Volume and Sludge Solids Concentration .... 84
5-13 Base Capital Cost of Sludge Drying Bed Dewatering as a Function
of Annual Volume and Sludge Solids Concentration 85
5-14 Base Annual O&M Cost of Sludge Drying Bed Dewatering as a
Function of Annual Volume and Sludge Solids Concentration .... 86
5-15 Area Required for Sludge Drying Bed Dewatering as a Function of
Annual Volume and Sludge Solids Concentration 87
5-16 Annual O&M Requirements for Sludge Drying Bed Dewatering as a
Function of Annual Volume and Sludge Solids Concentration .... 88
6-1 Base Capital Cost of Chemical Conditioning with Lime as a
Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 2 Percent 91
6-2 Base Capital Cost of C,hemical Conditioning with Lime as a
Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 4 Percent 92
6-3 Base Capital Cost of Chemical Conditioning with"Lime as a
Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 6 Percent 93
6-4 Base Annual O&M Cost o'f Chemical Conditioning with Lime as
a Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 2 Percent 94
6-5 Base Annual O&M Cost of Chemical Conditioning with Lime as
a Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 4 Percent ,; 95
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FIGURES (continued)
Number
Page
6-6 Base Annual O&M Cost of Chemical Conditioning with Lime as
a Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 6 Percent 96
6-7 Annual O&M Requirements for Chemical Conditioning with Lime as
a Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 2 Percent 97
6-8 Annual O&M Requirements for Chemical Conditioning with Lime as
a Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 4 Percent . 98
6-9 Annual O&M Requirements for Chemical Conditioning with Lime as
a Function of Annual Volume and Lime Dosage; Sludge Solids
Concentration = 6 Percent 99
6-10 Base Capital Cost of Chemical Conditioning with Ferric Chloride
as a Function of Annual Volume and Ferric Chloride Dosage;
Sludge Solids Concentration = 2 Percent 101
6-11 Base Capital Cost of Chemical Conditioning with Ferric Chloride
as a Function of Annual Volume and Ferric Chloride Dosage;
Sludge Solids Concentration = 4 Percent 102
6-12 Base Capital Cost of Chemical Conditioning with Ferric Chloride
as a Function of Annual Volume and Ferric Chloride Dosage;
Sludge Solids Concentration = 6 Percent 103
6-13 Base Annual O&M Cost of Chemical Conditioning with Ferric
Chloride as a Function of Annual Volume and Ferric Chloride
Dosage; Sludge Solids Concentration = 2 Percent 104
6-14 Base Annual O&M Cost of Chemical Conditioning with Ferric
Chloride as a Function of Annual Volume and Ferric Chloride
-Dosage; Sludge Solids Concentration = 4 Percent 105
6-15 Base Annual O&M Cost of Chemical Conditioning with Ferric
Chloride as a Function of Annual Volume and Ferric Chloride
Dosage; Sludge Solids Concentration = 6 Percent 106
6-16 Annual O&M Requirements for Chemical Conditioning with Ferric
Chloride as a Function of Annual Volume and Ferric Chloride
Dosage; Sludge Solids Concentration = 2 Percent 10?
6-17 Annual O&M Requirements for Chemical Conditioning with Ferric
Chloride as a Function of Annual Volume and Ferric Chloride
Dosage; Sludge Solids Concentration = 4 Percent 108
xii
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FIGURES (continued)
Number Page
6-18 Annual O&M Requirements for Chemical Conditioning with Ferric
Chloride as a Function of Annual Volume and Ferric Chloride
Dosage; Sludge Solids Concentration = 6 Percent 109
6-19 Base Capital Cost of Chemical Conditioning with Polymers as a
Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 2 Percent 110
6-20 Base Capital Cost of Chemical Conditioning with Polymers as a
Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 4 Percent Ill
6-21 Base Capital Cost of Chemical Conditioning with Polymers as a
Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 6 Percent 112
6-22 Base Annual O&M Cost of Chemical Conditioning with Polymers as
a Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 2 Percent 113
6-23 Base Annual O&M Cost of Chemical Conditioning with Polymers as
a Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 4 Percent ....... 114
i
6-24 Base Annual O&M Cost of Chemical Conditioning with Polymers as
a Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 6 Percent 115
i
6-25 Annual O&M Requirements for Chemical Conditioning with Polymers
as a Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 2 Percent 116
6-26 Annual O&M Requirements for Chemical Conditioning with Polymers
as a Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 4 Percent 117
6-27 Annual O&M Requirements for Chemical Conditioning with Polymers
as a Function of Annual Volume and Polymer Dosage; Sludge Solids
Concentration = 6 Percent 118
7-1 Base Capital Cost of Fluidized Bed Incineration as a Function
of the Weight of Dry Sludge Solids Incinerated Daily and Sludge
Solids Concentration 121
7-2 Base Annual O&M Cost of Fluidized Bed Incineration-as a Function
of the Weight of Dry Sludge Solids Incinerated Daily and Sludge
Solids Concentration. . 122
! xiii
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FIGURES (continued)
Number
7-3 Annual O&M Requirements for Fluidized Bed Incineration as a
Function of the Weight of Dry Sludge Solids Incinerated Daily
and Sludge Solids Concentration 123
7-4 Base Capital Cost of Multiple Hearth Incineration as a Function
of the Weight of Dry Sludge Solids Incinerated Daily and Sludge
Solids Concentration 125
7-5 Base Annual O&M Cost of Multiple Hearth Incineration as a
Function of the Weight of Dry Sludge Solids Incinerated Daily
and Sludge Solids Concentration 126
7-6 Annual O&M Requirements for Multiple Hearth Incineration as a
Function of the Weight of Dry Sludge Solids Incinerated Daily
and Sludge Solids Concentration . 127
8-1 Base Capital Cost of Windrow Sludge Composting as a Function
of the Weight of Dry Sludge Solids Composted Daily and Sludge
Solids Concentration 131
8-2 Base Annual O&M Cost of Windrow Sludge Composting as a Function
of the Weight of Dry Sludge Solids Composted Daily and Sludge
Solids Concentration 132
8-3 Annual O&M Requirements for Windrow Sludge Composting as a
Function of the Weight of Dry Sludge Solids Composted Daily
and Sludge Solids Concentration 133
8-4 Area Required for Windrow Sludge Composting as a Function of the
Weight of Dry Sludge Solids Composted Daily and Sludge Solids
Concentration 135
8-5 Base Capital Cost of Aerated Static Pile Sludge Composting as a
Function of the Weight of Dry Sludge Solids Composted Daily and
Sludge Solids Concentration 136
8-6 Base Annual O&M Cost of Aerated Static Pile Sludge Composting as
a Function of the Weight of Dry Sludge Solids Composted Daily
and Sludge Solids Concentration 137
8-7 Annual O&M Requirements for Aerated Static Pile Composting as
a Function of the Weight of Dry Sludge Solids Composted Daily
and Sludge Solids Concentration 138
8-8 Area Required for Aerated Static Pile Sludge Composting as a
Function of the Weight of Dry Sludge Solids Composted Daily. . . 142
9-1 Base Capital Cost of Liquid Sludge Truck Hauling as a Function
of Annual Volume Hauled and Round Trip Haul Distance 145
xiv
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FIGURES (continued) |
I
Number ' Page
9-2 Base Annual O&M Cost of Liquid Sludge Truck Hauling as a
Function of Annual Volume Hauled and Round Trip Haul Distance < . 146
9-3 Annual O&M Requirements for Liquid Sludge Truck Hauling as a
Function of Annual Volume Hauled and Round Trip Haul Distance . . 147
9-4 Base Capital Cost of Dewatered Sludge Truck Hauling as a
Function of Annual Volume Hauled and Round Trip Haul Distance . . 148
9-5 Base Annual O&M Cost of Dewatered Sludge Truck Hauling as a
Function of Annual Volume Hauled and Round Trip Haul Distance . . 149
9-6 Annual O&M Requirements for Dewatered Sludge Truck Hauling as a
Function of Annual Volume Hauled and Round Trip Haul Distance . . 150
9-7 Capital Cost Adjustment Multiplication Factor to Account for
Varying Days Per Year That Sludge Is Hauled 151
9-8 Base Capital Cost of Liquid Sludge Rail Hauling as a Function
of Annual Volume Hauled 153
9-9 North Central and Central Region: Base Annual O&M Cost of
Liquid Sludge Rail Hauling as a Function of Annual Volume
Hauled and Round Trip Haul Distance 154
9-10 Northeast Region: Base Annual O&M Cost of Liquid Sludge Rail
Hauling as a Function of Annual Volume Hauled and Round Trip
Haul Distance | 155
9-11 Southeast Region: Base Annual O&M Cost of Liquid Sludge Rail
Hauling as a Function of Annual Volume Hauled and Round Trip
Haul Distance '....' 156
9-12 Southwest Region: Base Annual O&M Cost of Liquid Sludge Rail
Hauling as a Function of Annual Volume Hauled and Round Trip
Haul Distance 157
9-13 West Coast Region: Base Annual O&M Cost of Liquid Sludge Rail
Hauling as a Function of Annual Volume Hauled and Round Trip
Haul Distance 158
9-14 Annual O&M Requirements for Liquid Sludge Rail Hauling as a
Function of Annual Volume Hauled 159
9-15 Base Capital Cost of Liquid Sludge Barge Hauling as a Function
of Annual Volume Hauled and Round Trip Haul Distance 162
9-16 Base Annual O&M Cost of Liquid Sludge Barge Hauling as a
Function of Annual Volume Hauled and Round Trip Haul Distance . . 163
xv
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FIGURES (continued)
Number Page
9-17 Base Capital Cost of a 1-Mile Liquid Sludge Transport Pipeline
and Pump Station(s) as a Function of Daily Volume Pumped and
Elevation Difference 165
9-18 Base Annual O&M Cost of a 1-Mile Liquid Sludge Transport
Pipeline and Pump Station(s) as a Function of Annual Volume
Pumped and Elevation Difference 166
9-19 Annual O&M Requirements for a 1-Mile Liquid Sludge Transport
Pipeline and Pump Station(s) as a Function of Annual Volume
Pumped and Elevation Difference 167
9-20 Base Capital Cost of a 5-Mile Liquid Sludge Transport Pipeline
and Pump Station(s) as a Function of Daily Volume Pumped and
Elevation Difference. 168
9-21 Base Annual O&M Cost of a 5-Mile Liquid Sludge Transport
Pipeline and Pump Station(s) as a Function of Annual Volume
Pumped and Elevation Difference 169
9-22 Annual O&M Requirements for a 5-Mile Liquid Sludge Transport
Pipeline and Pump Station(s) as a Function of Annual Volume
Pumped and Elevation Difference 170
9-23 Base Capital Cost of a 10-Mile Liquid Sludge Transport Pipeline
and Pump Station(s) as a Function of Daily Volume Pumped and
Elevation Difference 171
9-24 Base Annual O&M Cost of a 10-Mile Liquid Sludge Transport
Pipeline and Pump Station(s) as a Function of Annual Volume
Pumped and Elevation Difference 172
9-25 Annual O&M Requirements for a 10-Mile Liquid Sludge Transport
Pipeline and Pump Station(s) as a Function of Annual Volume
Pumped and Elevation Difference 173
9-26 Base Capital Cost of a Liquid Sludge Ocean Outfall as a
Function of Annual Volume Discharged and Outfall Length 174
9-27 Base Annual O&M Cost of a Liquid Sludge Ocean Outfall as a
Function of Annual Volume Discharged and Outfall Length 175
9-28 Annual O&M Requirements for a Liquid Sludge Ocean Outfall as
a Function of Annual Volume Discharged and Outfall Length .... 176
10-1 Base Capital Cost of Applying Sludge to Cropland as a Function
of Annual Sludge Volume Applied and Dry Solids Application Rate . 178
xvi
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FIGURES (continued) :
Number '' Paige_
10-2 Base Annual O&M Cost of Applying Sludge to Cropland as a
Function of Annual Sludge Volume Applied and Dry Solids
Application Rate. 179
10-3 Annual O&M Requirements for Applying Sludge to Cropland as a
Function of Annual Sludge Volume Applied and Dry Solids
Application Rate. 180
10-4 Multiplication Factor to Adjust Sludge Application to Cropland
Costs in Figure 10-1 for Variations in Days of Application Per
Year .; 181
10-5 Base Capital Cost of Applying Sludge to Marginal Land for
Reclamation as a Function of Annual Sludge Volume Applied .... 184
10-6 Base Annual O&M Cost of Applying Sludge to Marginal Land for
Reclamation as a Function of Annual Sludge Volume Applied and
Dry Solids Application Rate 185
10-7 Annual O&M Requirements for Applying Sludge to Marginal Land
for Reclamation as a Function of Annual Sludge Volume Applied . . 186
10-8 Multiplication Factor to Adjust Sludge Application to Marginal
Land Costs in Figure 10-5 for Variations in Days of Application
Per Year . . 188
10-9 Base Capital Cost of Applying Sludge to Forest Land as a
Function of Annual Sludge Volume Applied and Dry Solids
Application Rate 190
10-10 Base Annual O&M Cost of Applying Sludge to Forest Land as a
Function of Annual Sludge Volume Applied and Dry Solids
Application Rate 191
10-11 Annual O&M Requirements for Applying Sludge to Forest Land as
a Function of Annual Sludge Volume Applied and Dry Solids
Application Rate . . . ., 192
10-12 Multiplication Factor to Adjust Sludge Application to Forest
Land Costs in Figure 10-9 for Variations in Days of Application
Per Year f 194
10-13 Base Capital Cost of Applying Sludge to a Dedicated Disposal
Site as a Function of Annual Sludge Volume Applied and Dry
Solids Application Rate.' 197
10-14 Base Annual O&M Cost of Applying Sludge to a Dedicated Disposal
Site as a Function of Annual Sludge Volume Applied and Dry
Solids Application Rate., 198
xvii
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FIGURES (continued)
Number Page
10-15 Annual Q&M Requirements for Applying Sludge to a Dedicated
Disposal Site as a Function of Annual Sludge Volume Applied
and Dry Solids Application Rate . 199
10-16 Multiplication Factor to Adjust Sludge Application to Dedicated
Disposal Site Costs in Figure 10-13 for Variations in Days of
Application Per Year 200
10-17 Base Capital Cost of a Municipally Owned Sludge Landfill as a
Function of Annual Sludge Volume Received 202
10-18 Base Annual O&M Cost of a Municipally Owned Sludge Landfill as
a Function of Annual Sludge Volume Received 203
10-19 Annual O&M Requirements for a Municipally Owned Sludge Landfill
as a Function of Annual Sludge Volume Received. 204
10-20 Land Area Required for a Sludge Landfill as a Function of Annual
Sludge Volume Received 206
10-21 Weight of Sludge Dry Solids Content as a Function of Wet Sludge
Volume and Solids Concentration 208
11-1 Base Capital Cost of Facultative Lagoon Sludge Storage as a
Function of Lagoon Storage Capacity 215
11-2 Base Annual O&M Cost of Facultative Lagoon Sludge Storage as a
Function of Lagoon Storage Capacity 216
11-3 Annual O&M Requirements for Facultative Lagoon Storage as a
Function of Lagoon Storage Capacity 217
11-4 Base Capital Cost of Enclosed Tank Sludge Storage as a Function
of Tank Storage Capacity 219
11-5 Base Annual O&M Cost of Enclosed Tank Sludge Storage as a
Function of Tank Storage Capacity 220
11-6 Annual O&M Requirements for Enclosed Tank Sludge Storage as a
Function of Tank Storage Capacity 221
11-7 Base Capital Cost of Unconfined Pile Dewatered Sludge Storage
as a Function of Facility Storage Capacity. 222
11-8 Base Annual O&M Cost of Unconfined Pile Dewatered Sludge Storage
as a Function of Facility Storage Capacity. 223
11-9 Annual O&M Requirements for Unconfined Pile Dewatered Sludge
Storage as a Function of Facility Storage Capacity 224
xvi i i
-------
TABLES
I
Number ' Page
1-1 Input Parameters Used When Utilizing the CAPDET,Program 4
2-1 Typical Influent Solids Concentrations, Capture Values, and
Expected Effluent Solids Concentrations from Various Treatment
Processes 15
2-2 Typical Parameters Required for Calculating a Mass Balance for
the Conversion Processes, ". 18
2-3 Summary of Calculated Sludge Volume and Solids Concentration
for Each Flow Stream Shown in Figure 2-2 and Described in Mass
Bal ance Exampl e .... :. 20
2-4 Development of Total Capital Costs 30
2-5 Devel opment of Total Annual O&M Costs 31
2-6 Summary of Base Capital and Base Annual O&M Costs Described
in Example : 38
2-7 Development of Total Capital Costs for Example 39
2-8 Development of Total Annual O&M Costs for Example 40
8-1 Assumptions Used in Obtaining Costs and Requirements for Windrow
Composting Shown in Figures 8-1 Through 8-4 134
8-2 Assumptions Used in Obtaining Costs and Requirements for Aerated
Static Pile Composting Shown in Figures 8-5 Through 8-8 140
10-1 Assumptions Used in Developing Cost Requirement Curves for Land
Application of Sludge to Cropland 182
10-2 Assumptions Used in Developing Cost Requirement Curves for Land
Application of Sludge to Marginal Land. 189
10-3 Assumptions Used in Developing Cost Requirement Curves for Land
Application of Sludge to Forest Land Site 195
10-4 Assumptions Used in Developing Cost Requirement Curves for Land
Application of Sludge to Dedicated Disposal Site 201
xix
-------
TABLES (continued)
Number Page
10-5 Assumptions Used in'Devel oping Cost Requirement Curves for Land
Application of Sludge to Sludge Landfill 207
10-6 Typical Ranges of Sludge Application Rates (DSAR) for Various
Land Application Unit Processes 210
10-7 Typical 1984 Land Preparation Costs for Sludge Application. ... 213
B-l Summary of Selected Cost Information Sources from the Technical
Literature 520
xx
-------
SECTION 1
INTRODUCTION
1.1 General ;
This cost handbook is designed for use by municipal wastewater treatment
and sludge management authorities, program and project planners, government
regulatory officers, designers, and consulting engineers to assist in obtain-
ing preliminary cost estimates for 34 common municipal wastewater sludge man-
agement processes. A review of the table of contents shows the sludge manage-
ment processes included. '<
Preliminary base capital costs and base annual operation and maintenance
(O&M) costs are obtained in this manual through the use of curves developed
for each of the 34 sludge management processes. These curves are based on the
cost algorithms contained in Appendix A. The cost curves allow the user to
rapidly obtain approximate cost estimates for sludge management processes
based on only one or two process variables (e.g., annual sludge volume and
distance hauled from treatment1 plant). In preparing the cost curves, average
default values were assumed for most of the variables contained in the Appen-
dix A cost algorithms. The majority of the cost algorithms are quite complex,
having more process variables than the curves, allowing the user greater flex-
ibility to adjust to site-specific characteristics. Therefore, while the
curves are helpful for rapidly obtaining approximate costs for preliminary
evaluation, it is recommended :that the cost algorithms in Appendix A be used
when more accurate site-specific cost estimates are desired.
The cost curves and algorithms for each process generally cover a range
up to 100 million gallons of ;sludge per year. This range is approximately
equivalent to a wastewater treatment plant of at least 50 mgd. The range was
selected to include plants where supplemental cost information might be most
useful.
For each sludge management process in this manual, a base capital cost
curve and a total base annual^ O&M curve are presented. In addition, annual
O&M component curves are presented for most processes. Base capital cost
curves include mechanical equipment, concrete, steel, electrical and instru-
mentation, and installation labor. Specific items included in base capital
costs are detailed in the process descriptions which accompany the algorithms
in Appendix A. Annual O&M component curves provided for each process include
the following, where applicable:
• Annual labor hours required.
• Annual electrical energy required.
« Annual fuel required.
• Annual chemical requirements.
-------
t Annual maintenance material costs.
t Other annual O&M requirements, as needed.
These curves allow the user flexibility to specify costs for these components,
which may vary significantly with geographic region. In addition, the user
can easily identify the cost components which have a major impact on overall
O&M costs.
All cost curves are based on fourth quarter 1984 costs; Engineering News
Record Construction Cost Index (ENRCCI) equals 4,171. Appropriate cost
indices should be used to adjust cost estimates for future years, as discussed
in Section 2 of this manual.
Appendix A contains cost algorithms which require site-specific and pro-
cess design input. The degree of detail varies among the algorithms; however,
cost estimates based on direct use of the algorithms should be sufficiently
accurate for Step 1 Construction Grant Planning purposes, as defined by Appen-
dix A to Subpart E of 40 CFR, Part 35. Most of the algorithms can be hand-
calculated in less than 20 minutes per trial.
The main emphasis of this manual is in obtaining preliminary cost esti-
mates for various sludge management processes. Design parameters presented
are "typical values" intended to guide the user in this pursuit. Obviously,
the more accurate design information to which a user has access, the more
accurate the resulting costs. A large amount of literature is available from
which supplementary design information can be obtained. These manuals are:
t Process Design Manual - Sludge Treatment and Disposal (EPA-625/1-79-
011), Reference 1.
t Process Design Manual - Dewatering Municipal Wastewater Sludge (EPA-
625/1-82-014), Reference 2.
t Process Design Manual - Land Application of Municipal Sludge (EPA-
625/1-83-016), Reference 3.
t Process Design Manual - Municipal Sludge Landfills (EPA 625/1-78-010),
Reference 4.
Before attempting to use the cost curves provided in this manual or the
algorithms in Appendix A, it is very important to read and understand Section
2 (User's Guide). Failure to do so may result in inaccuracies in cost esti-
mating. This section also provides several example calculations.
1.2 Project Development History
The process cost algorithms for lime stabilization (Section 4.4), com-
posting (Section 8), transport (Section 9), land application/disposal (Section
10), and storage (Section 11) were developed by SCS Engineers for addition to
and enhancement of the existing Computer Assisted Procedure for the Design and
Evaluation of Wastewater Treatment Systems (CAPDET). Cost algorithms for the
remaining processes covered in this manual were already contained in the
CAPDET program.
-------
The CAPDET program was originally developed in 1973 by the U.S. Army
Corps of Engineers to provide ^wastewater treatment system planners with a tool
for rapidly generating planning-level cost estimates for alternative waste-
water treatment systems, using limited user-specified input (i.e., the types
of design and cost input which are readily available during a project planning
phase). Subsequent CAPDET revisions were made with assistance from the U.S.
Environmental Protection Agency (EPA). CAPDET is currently (1985) available
on the NCC/IBM system at EPA in Research Triangle Park, North Carolina.
1.3 Development of the Algorithms and Cost Curves
Cost algorithms and curves for 17 processes covering lime stabilization,
composting, transport, land application/disposal, and storage were derived as
follows:
1. Processes were broken down into significant component parts. For
example, the truck haul of liquid sludge algorithm includes 23 com-
ponent parts ranging from distance hauled to driver salary.
2. Formulas were developed to relate each of the component parts of the
algorithm to the capital and annual O&M costs for the sludge manage-
ment process being estimated.
3. Fourth quarter 1983 average costs were developed for purchased and
constructed items such as equipment, vehicles, and sludge-loading
facilities, and these were integrated into the algorithms.
4. The cost algorithms were applied to actual projects which have been
implemented in various U.S. locales, and the algorithm cost outputs
compared with actual reported capital and O&M costs. Where signifi-
cant differences were found, the cost algorithms were reviewed and
revised as necessary to conform more closely to actual project costs.
5. Cost curves were generated through use of each algorithm by inputting
the parameters listed under the assumptions section for the corre-
sponding curve (usually algorithm default values). Costs were up-
dated to last quarter 1984 values by inputting appropriate cost
indices. The resulting cost curves were compared with a variety of
other cost curves in the literature developed by EPA and others.
Where signficant differences were found, the cost curves were re-
viewed and corrected, as necessary.
I
The remaining sludge management processes are contained in the CAPDET
program. Costs were derived using the program by varying sludge volume and
solids concentration, and utilizing CAPDET default values. Where the CAPDET
program requires additional user input, parameters listed in Table 1-1 (last
quarter 1983 values) and in the algorithm development subsection of each algo-
rithm were used. The resulting costs were compared with a variety of other
costs in the literature developed by EPA and others. Where significant dif-
ferences were found, appropriate changes were made. Curve costs were subse-
quently updated to last quarter 1984 values during the latter stages of this
project, so that the curves would be as current as possible.
-------
TABLE 1-1
INPUT PARAMETERS USED WHEN UTILIZING THE CAPDET PROGRAM*
Parameter Value ($)
Engineering News Record Construction Cost Index (ENRCCI) 4,006.00
Marshall and Swift Equipment Cost Index (MSECI) 751.00
EPA Construction Cost Index 224.00
Pipe Cost Index 410.00
Labor Rate ($/hr) 18.00
Operator Class II ($/hr) 13.00
Electricity ($/kWhr) 0.09
Chemical Costs:
Lime ($/lb) 0.05
Alum ($/lb) 0.23
Iron Salts ($/lb) 0.19
Polymer ($/lb) 2.80
Building ($/ft^) 70.00
Excavation ($/ydJ) 2.50
Wall Concrete ($/yd^) 250.00
Slab Concrete (S/vd"3) 130.00
Canopy Roof ($/ft2) 15.75
Handrail ($/ft) 33.00
Pipe Installation Labor Rate ($/hr) 18.00
8-inch Pipe ($/ft) 15.00
8-inch Pipe Bend ($/unit) 106.00
8-inch Pipe Tee ($/unit) 159.00
8-inch Pipe Valve ($/unit) 1,200.00
Crane Rental ($/hr) 100.00
* Basis is fourth quarter 1983.
-------
During draft handbook review, costs obtained using the CAPDET program
were determined to have substantial errors. For the following processes, new
cost algorithms were generated based on cost information obtained from the
literature: :
Thermal conditioning. <
Centrifuge dewatering.
Belt filter dewatering.
Recessed plate filter press dewatering.
Sludge drying bed dewatering.
Costs generated using a combination of some CAPDET costs along with other
costs obtained in the literature were:
Vacuum filter dewatering.
Sludge drying bed dewatering.
Chemical conditioning with lime.
Chemical conditioning with ferric chloride.
Chemical conditioning with polymers.
Fluidized bed incineration.
Multiple hearth incineration.
Costs for the remaining sludge management processes were derived wholly from
the CAPDET program.
I
Base capital costs and O&M component requirements obtained using both the
CAPDET program and cost information from the literature were fit to equations
using a multiple regression program. These equations appear in the cost algo-
rithms located in Appendix A. | Costs and requirements were expressed as func-
tions of the parameter most closely related to costs or requirements. Equa-
tions were developed to provide user flexibility in terms of site-specific
parameters without overcomplicating the algorithm. In some cases, this re-
sulted in an algorithm that is more limited than the more complex ones. How-
ever, the costs obtained arei reasonable for estimating purposes. Specific
information on algorithm development and references used to correct costs are
presented in the introductory descriptions for each process in Appendix A.
1.4 Relative Accuracy of the Costs Presented
In preparing cost algorithms and cost curves for the processes covered in
the manual, the authors had access to a wealth of existing technical and cost
information for some processes (e.g., truck hauling of sludge), and virtually
no existing full-scale' operation information for other processes which are
rarely used (e.g., rail hauling of sludge). In addition, some processes
included in the manual (e.g., sludge storage facilities) are relatively
straightforward, while others (e.g., ocean outfall sludge disposal) are very
complex and difficult to generalize because of site-specific variables. For
these reasons, the authors' level of confidence in the accuracy of the cost
algorithms and cost curves presented varies between the different processes.
-------
This level of confidence is expressed subjectively in the following listing:
1. Sludge management processes with a low level of accuracy confidence:
- Pipeline transport of liquid sludge.
- Ocean disposal by submarine outfall.
- Rail hauling of liquid sludge.
- Barge hauling of liquid sludge.
- Disposal in sludge landfill.
2. Sludge management processes with a medium level of accuracy confi-
dence:
- Land application to cropland.
- Land application to marginal or disturbed land for reclamation.
- Land application to forest land.
- Land application to dedicated disposal site.
- Lime stabilization.
- Thermal conditioning (also known as Zimpro Process, low-pressure
oxidation, and heat treatment).
3. Sludge management processes with a high level of accuracy confidence:
- All other processes contained in this manual.
An approximate quantitative value may be assigned to the low, medium, and
high levels of accuracy confidence. By comparison with levels given for simi-
lar cost estimates on pages H-3 and H-4 in Reference 5, low may approximate +
50 percent; medium, ± 30 percent; and high, ± 15 percent. It must be empha-
sized, however, that levels of confidence which have statistical significance
could only be established by numerous comparisons of predicted costs with
actual project costs.
Accuracy of curves with respect to the specific calculation methods has
likely been affected by smoothing employed when drawing curves through the
plotted points. The curves should actually have discontinuities due to two
different factors. First, some items of equipment, e.g., earth-moving equip-
ment, are only available in a limited number of sizes. Also, several separate
functions have been used in many cases to cover different sections of the
entire range of some of the parameters. The discontinuities caused by these
factors are somewhat arbitrary, however, since different sizes of equipment
are available at different times from different manufacturers, and the way a
cost function is broken into several segments would be dependent on choices
made by a specific cost estimator. For these reasons, it was decided to
smooth the curves in the Handbook to better represent an "average" cost.
1.5 Other Sludge Management Processes Not Included in This Manual
There are a number of other processes applicable to municipal sludge man-
agement which have not been included in this manual, since a sufficient cost
data base has not been firmly established. These other processes include:
t Vacuum-Assisted Drying Beds - This process is a modification of drying
bed dewatering, in which a vacuum is applied to an underdrain system,
-------
thereby increasing the drainage rate significantly. Disadvantages of
the system result from cracking of the cake and breakthrough of the
vacuum before thorough drying occurs.
• In-Vessel Composting - In this process, composting is accomplished in
an enclosed system which permits controlled mixing and aeration, along
with containment of odorous gases that can be treated prior to re-
lease.
• Carver-Greenfield Sludge Drying Process - This process utilizes mul-
tiple effect evaporation with an oil carrier to increase fluidity at
high solids concentrations. Units are currently being installed in
Los Angeles, and are under consideration at several other locations.
• Staged Digestion - Various combinations have been investigated using
several stages of digestion with both mesophilic (low temperature,
around 35 °C) and thermophilic (higher temperature, around 55 °C)
units. '
• 'Advanced Membrane Technology - Includes hyperfiltration units which
have a membrane deposited on porous stainless steel tubes. Initial
sludge studies have demonstrated that elimination of chemical condi-
tioning may pay back increased capital costs when compared to belt
filtration. I
• Freeze Conditioning - For cold climates, natural freezing can be used
to advantage to make sludge dewatering easier on sand drying beds.
This process has been,investigated by the U.S. Army Corps of Engineers
Cold Regions Research and Engineering Laboratory, Hanover, New
Hampshire.
• Conversion of Sludge to Gas and Oil - Processes similar to those sug-
gested for fossil fuel gasification and liquefaction have also been
investigated for sludge, and look promising.
• Irradiation of Sludge - Disinfection has been studied using gamma
radiation from radioactive isotopes, electron beams, and microwaves.
• Additional Processes - Alternative sludge management processes that
have been investigated include: enzyme addition to digestion, ultra-
sonics, combined oxygen and ozone contacting, and clathrate freezing
using a liquid refrigerant to form separate crystals with water to
effect dewatering.
1.6 Other Sludge Management Process Cost Information in the Technical
Literature :
Appendix B of this manual contains an annotated bibliography and refer-
ence chart of other sources of sludge management process cost information in
the technical literature. !
-------
1.7 English to Metric Conversion Factors
Appendix C of this manual contains metric equivalents and conversion fac-
tors from U.S. customary to metric units for commonly used units of expression
in sludge management.
1.8 References
1. Process Design Manual: Sludge Treatment and Disposal. Technology Trans-
fer Series. EPA-625/1-79-011, Center for Environmental Research Informa-
tion, Cincinnati, Ohio, September 1979. 1135 pp.
2. Process Design Manual: Dewatering Municipal Wastewater Sludges. EPA-
625/1-82-014, Center for Environmental Research Information, Cincinnati,
Ohio, October 1982. 222 pp.
3. Process Design Manual: Land Application of Municipal Sludge. Technology
Transfer, EPA-625/1-83-016, Center for Environmental Research Information,
Cincinnati, Ohio, October 1983. 436 pp.
4. Process Design Manual: Municipal Sludge Landfills. EPA-625/1-78-010,
Environmental Research Information Center, Cincinnati, Ohio, October 1978.
5. Areawide Assessment Procedures Manual. EPA-600/9-76-014. U.S. Environ-
mental Protection Agency, Municipal Environmental Research Laboratory,
Cincinnati, Ohio, July 1976. (Available from NTIS as PB271863/Set.)
-------
SECTION 2
USER'S GUIDE
2.1 General
Users should read and understand this section prior to estimating costs
with the cost curves or cost algorithms contained in this manual. If the user
goes directly to the cost curves or algorithms without performing the prelimi-
nary steps required by this section, the resulting sludge management cost
estimates may be over- or underestimated.
2.2 Developing the Sludge Management Process Chain
The user should develop a sludge management process chain (and/or alter-
nate chains). This will usually consist of a figure (or figures) which shows
the sequence of processes to be used in the entire sludge management chain,
starting with the raw si udge and ending with final disposal or recycling.
Figure 2-1 shows the sludge management processes for which costs are included
in this manual. Many feasible; processing combinations are possible, as shown
in Figure 2-1. It is assumedi that the user will develop a rational sludge
management process scheme (and/or alternate schemes) prior to beginning cost
estimating.
2.3 Developing the Mass Balance of Sludge Volume and Sludge Concentration
Entering and Leaving Each Process
Most cost algorithms for sludge management processes in this manual have,
as necessary input data, the volume of sludge entering the process (not neces-
sarily the entire raw sludge flow), and the suspended solids content of the
sludge entering the process (not necessarily the raw sludge solids concentra-
tion). It is essential, therefore, in using this manual to compute an approx-
imate mass balance to obtain the sludge volume and sludge solids concentration
entering and leaving each process in the entire sludge management scheme.
The inexperienced cost estimator might mistakenly believe that the volume
of raw sludge is the same as the volume of final treated sludge leaving the
management scheme. This is virtually never the case because each successive
sludge treatment process normally tends to reduce the mass and volume of
sludge. Therefore, the mass and volume of the final treated sludge leaving
the management scheme is typically only a fraction of the initial raw sludge
volume. Similarly, the sludge solids concentration changes as the sludge pro-
ceeds through a series of treatment processes.
-------
FIGURE 2-1
SLUDGE MANAGEMENT PROCESSES INCLUDED IN THIS MANUAL
o
M**t*nit*r
Trtttnent
Chi In
Sludge
Haw Battt
Biological Sludge
Ho Cheufcal Conditioning
Conditioning
Thernil Conditioning
Continued
from Above ^
-+
-+
™*
-*>
-+
-»>
-*
L*.
Ho TM chen Ing
Gravity Thickening of
Prlnary Sludge Only
Biological Sludge Only
Gravity Thickening
of Combined S ludges
OAf Thickening of
Combined S ludgts
Centrifuge Thickening of
Primary Sludge Only
Centrifuge Thickening of
Biological Sludge Only
Centrifuge Thickening of
Cowblntd Slutfgei
-»h
-*
"»
-*
-*•
-*•
-»•
^J
— ^
P*
— *»
-^
-*
-»•
-*>
No Stabilization
Anaerobic Digestion
Aerobic Oigestlon-
Heehanicil Aeration
Aerobic Bige*tion-
Diffu*ed Aention
Hmt Stablt iz»t ion
Thermal Conditioning
-^|
—*
-^
-^
-^
-J
Below
Sheet
-------
FIGURE 2-1 (CONTINUED)
Continued from
Previous Page
No
Oeviat
eMng
Vacuum
Filter
Belt
Filter
Press
Plate
Filter
Press
CentH f uge
Dry
ing
Beds
No
Incintrat ion
Fluidized Bed
Incineration
Multiple Hearth
Inei nerat ion
Continued
Below
r*
^
^^
Liquid
Sludge
Dewatered
S ludge
Incinerator
Ash Product
«fc
^^
-*»
L»
Windrow
Composting
Static Aerated
Pile Composting
-*
->
1— ¥
I
1
bl b
1
•"~T
Long-Tern Lagoon
or Pile Storage
at or near POTW
Short-Term, Interim
Storage at POTI*
-*|
J
^.1 ^ Continued on
"•^^•^^ Next Sheet
J
••^
-------
FIGURE 2-1 (CONTINUED)
Continued from
Previous Page
ro
Puap Station for
Liquid Iludgt
Truck Loidlng Faculty
for Liquid Sludge
Truck Loading Facility
for tewatered, Coaposted,
or Incinerated Sludge
•allhead Loading facility
for L Iquld Sludge
•allhead Loading Facility
for Bevatered or
Coaposted Sludge
•ocfctlde Barge Loading
facility for Liquid Sludge
Ocean Hspoial by
Ocean OutfalI
Pipeline for
Liquid Sludge
for LIquld Sludge
Deuatered,
Composted,
Barge Haul to-Ocean
DuMpIng for Liquid Sludge
Continued
Below
nil Hiul for
Liquid Sludgt
Unloading F
for Liquid
•cltltr
Sludgt
flail Heul for DetfBtrred
or COM pot ted S ludge
Unloading Facility
for Dewatervd or Coapotfttd
Sludge
Ocean ottpotal
by Barge
Continued
from Above
Long-Ter* Storage
at Dltpoiat Site
Short-Term Storage
at Oltpoval Site
No Storage at
•Itpoial Site
Landfill Disposal
l*nd Spreading on
Food Chain Crops
Land Spreading on Non-
food Chain Crops
(e.g.. Forest Land,
Strip Nine Hec laaation.
Cotton, Etc.)
Land Spreading on
Dedicated Sludge
Disposal Site
-------
In order to estimate the sludge volume and solids concentration entering
each successive treatment process, the cost estimator should perform the fol-
lowing steps:
1. Calculate the volume,: sol ids concentration, and weight of dry sludge
solids produced by the wastewater treatment chain.
2. Draw a flowsheet of the proposed sludge treatment process chain.
3. Identify all streams entering and leaving each sludge management pro-
cess. The streams would generally consist of the influent, effluent,
and recycle streams.
4. For each process, identify and calculate the relationship of entering
and leaving streams to one another in terms of mass, volume, and
solids concentration. To do this requires knowledge of the approxi-
mate solids capture capabilities and conversion parameters for each
management process. Table 2-1 provides typical solids capture capa-
bilities and expected, sludge concentrations from various treatment
processes. Table 2-2 provides typical parameters required for calcu-
lating a mass balance for the conversion processes. These tables can
serve as guides, unless more accurate design information is available
for the specific sludge and sludge processes under consideration.
Solids capture and conversion parameters for each sludge management
process depend on a number of factors, including but not limited to
the following:
• Type of sludge treated, particularly the percentage of waste-acti-
vated si udge.
• Whether the sludge has been stabilized.
t Type and amount of conditioning chemicals used.
I
• Hydraulic and mass loading rates to process.
5. Tabulate sludge volume'and solids concentration for each stream iden-
tified in Step 3. !
2.4 Mass Bal ance Exampl e
The steps involved in computing a mass balance are detailed in the fol-
lowing example for a treatmentj plant with a design capacity of 20 mgd. The
proposed sludge treatment process chain is shown on Figure 2-2. Letter desig-
nations are provided for each 'stream entering and leaving the process. For
example, Stream A is the incoming raw primary sludge to the gravity thickener;
Stream M is the decant return; from the gravity thickener to the wastewater
treatment chain; Stream B is the subnatant from the gravity thickener, etc.
These letter designations are cross-referenced on the table of sludge volume
and solids concentration identified in Step 5 above. A completed version of
this table is shown on Table 2-3 for the mass balance developed in this sub-
section.
13
-------
FIGURE 2-2
EXAMPLE FLOWSHEET FOR SLUDGE TREATMENT PROCESS CHAIN SHOWING FLOW STREAMS
ENTERING AND LEAVING EACH SLUDGE MANAGEMENT CHAIN UNIT PROCESS
Raw Sludge from
Primary Sedimentation
Uaste Activated Sludge
fro* Secondary ClaHfler
i
Decant
Return
Gravity
Thickener
[«
atant ^P^
jrn ^^^^
crate ^^^^
urn ^^^^
Is
Digestion
Thickener
1"
i'
Chemical
Conditioning
4'
Centrifuge
DewateHng
1"
Deuatered Sludge
Truck Haul
I'
Sludge Application
to Cropland
a sol
mmmmm^ (Con
a
•mmmM ch
^^^ Addlt
» L
1
Sldestrea.
Return
Solids Destroyed
(Converted to Gas
and Hater)
Chemical
* Letter designations for streams described
1n text and shown 1n Table 2-1.
-------
TABLE 2-1
i
TYPICAL INFLUENT SOLIDS CONCENTRATIONS, CAPTURE VALUES, AND EXPECTED
EFFLUENT SOLIDS CONCENTRATIONS FROM VARIOUS TREATMENT PROCESSES
Typical
1 Influent Process Effluent
Solids Solids Solids
Concentration Capture Concentration
Process (%) (%) (%) Reference
Gravity Thickeners
Primary Only \ 2-7 85-92 4-10 1,2
Primary and Waste-Activated 1.5-6 80-90 3-7
Primary and Trickl ing Filter 3-6 80-90 7-10
Humus
Flotation Thickener
Waste-Activated Only , 0.4-1.5 80-95 2-7 3
Anaerobic Digester
Primary Only 2-10 3-12
Primary and Waste-Activated 1,5-6 2-8
Primary and Trickling Filter 2-6 3-8
Humus
Aerobic Digester
Primary Only ; 2-6 2.5-7 3
Primary and Waste-Activated 1.5-4 2-5
Waste-Activated Only ' 0.3-2 0.8-2.5
Thermal Conditioning
Primary Only : 1-6 90-92 1.5-8 3, 5
Primary and Waste-Activated 1-6 90 1.5-12
Centrifuge Dewatering ,
Primary Only 4-8 90-97 20-40 3
Primary and Waste-Activated 0.5-3 85-90 16-25
Primary and Trickl ing Filter i 2-5 90-97 20-30
Humus i
Anaerobically Digested Primary 1-8 85-99 12-30
and Waste-Activated '
Thermally Conditioned Primary \ 4-8 85-99 38-50
and Waste-Activated
15
-------
Table 2-1 (continued)
Process
Belt Filter Press
Primary Only
Primary and Waste-Activated
Primary and Trickling Filter
Humus
Anaerobically Digested Primary
and Waste-Activated
Thermally Conditioned Primary
and Waste-Activated
Pressure Filtration
Primary Only
Waste-Activated Only
Primary and Waste-Activated
Primary and Trickling Filter
Humus
Anaerobically Digested Primary
and Waste-Activated
Thermally Conditioned Primary
and Waste-Activated
Vacuum Filtration
Primary Only
Waste-Activated Only
Primary and Waste-Activated
Primary and Trickling Filter
Humus
Anaerobically Digested Primary
and Waste-Activated
Thermally Conditioned Primary
and Waste-Activated
Drying Beds
Primary Only
Waste-Activated Only
Primary and Waste-Activated
Primary and Trickling Filter
Humus
Anaerobically Digested Primary
and Waste-Activated
Thermally Conditioned Primary
and Waste-Activated
Typical
Influent Process Effluent
Solids Solids Solids
Concentration Capture Concentration
(%) (%) (*)
3-10
3-6
3-6
' 1-8
4-8
5-10
3-5
3-6
3-6
' 2-10
3-7
3-8
3-5
2-4
2-4
t 2-8
3-7
2-9
0.7-4
2-5
2-5
' 3-8
3-7
85-99
85-99
85-99
85-99
85-99
85-99
85-99
85-99
85-99
85-99
85-99
90-98
75-80
85-99
85-99
70-80
70-95
>99
87
. 85-100
85-100
86
99
28-44
20-40
20-40
38-50
38-50
45-50
37-45
35-50
35-50
40-50
30-48
25-30
12-18
15-30
15-30
15-28
30-50
20-40
10-20
10-30
10-30
10-45
15-45
Reference
3, 6
3, 6
3, 6
3, 4
16
-------
Table 2-1 (continued)
Process
•Multiple Hearth Incineration
Fluidized Bed Incineration
Windrow Composting
Static Aerated Pile Composting
Typical.
Influent Process Effluent
Solids Solids Solids
Concentration Capture Concentration
(%) {%) (%) Reference
16-40 7
', 15-60 7
15-40 45-65 7
30-50 40-65 7
17
-------
TABLE 2-2
TYPICAL PARAMETERS REQUIRED FOR CALCULATING A MASS BALANCE
FOR THE CONVERSION PROCESSES
Process
Anaerobic Digestion
Aerobic Digestion
Lime Stabilization
Thermal Conditioning
Chemical Conditioning:
- Lime
- Ferric Chloride
- Polymers
Parameter
Influent volatile solids
Volatile solids destroyed
Return stream suspended solids
concentration
Influent volatile solids
Volatile solids destroyed
Return stream suspended solids
concentration
Dosage - Primary sludge
Dosage - Activated sludge
Dosage - Combined sludge
Raw solids concentration
Influent volatile solids
Volatile solids destroyed
Return stream suspended solids
concentration
Raw primary and waste activated
Digested primary and waste activated
Primary
Waste activated
Digested combined
Primary
Waste activated
Digested combined
50-80%
40-60%
3,000-15,000 mg/1
50-80%
33-70%
5,000-30,000 mg/1
0.10-0.15 Ib/lb dry
sol i ds
0.30-0.50 Ib/lb dry
solids
0.20-0.40 Ib/lb dry
solids
1.5-15%
50-80%
30-40%
1,000-5,000 mg/1
110-300 Ib/ton dry
sol i ds
160-370 1b/ton dry
solids
40-120 1b/ton dry
solids
120-200 1 b/ton dry
solids
60-200 1 b/ton dry
solids
0.5-1.0 1b/ton dry
solids
8-15 1 b/ton dry
solids
5-12 1 b/ton dry
solids
18
-------
Table 2-2 (continued)
Process
Composting
Parameter
Solids concentration of
Solids concentration of
Solids concentration of
Solids concentration of
mixture
Volatile solids concentration of
sludge cake - Digested sludge
Volatile solids concentration of
si udge cake - Raw si udge
Volatile solids concentration
si udge cake
recycle
bulki ng agent
compost
recycl e
Volatile
bul king
Volatile
compost
Volatile
cake
Volatile
Vol atil e
agent
Volatile
product
sol ids
agent
sol ids
of
concentration of
of
concentration
mixture
solids destroyed in sludge
solids destroyed in recycle
solids destroyed in bulking
solids destroyed in compost
20-50%
60-75%
50-85%
40-50%
40-60%
60-80%
0-90%
55-90%
40-80%
33-56%
0-20%
0-40%
20-60%
19
-------
TABLE 2-3
SUMMARY OF CALCULATED SLUDGE VOLUME AND SOLIDS CONCENTRATION FOR EACH FLOW STREAM
SHOWN IN FIGURE 2-2 AND DESCRIBED IN MASS BALANCE EXAMPLE*
Fl ow Stream Letter
Designation in Figure 2-2
and Brief Description
A.
B.
C.
D.
E.
F.
G.
H.
I.
H.
N.
P.
Q.
R.
S.
Primary Sludge
Thickened Primary
SI udge
Waste Activated Sludge
Thickened Waste
Activated Sludge
Combined Sludge
to Digestion
Digested Sludge
Withdrawal
Chemically Conditioned
SI udge
Dewatered SI udge
Haul ed Dewatered SI udge
Gravity Thickener
Sidestream
DAF Thickener Sidestream
Digester Supernatant
Return
Solids Destroyed
in Digester
Dewatering Centrate
Return
Conditioning Chemical
Added
Cal cul ated
Average
Solids, DSS
(1 b/day)
26,000
23,400
10,400
9,400
32,800
21,600
24,800
22,800
22,800
2,600
1,000
1,400
9,800
2,000
3,200
Cal cul ated
Average
Volume, SV
(gal /day)
156,000
70,100
250,000
38,000
108,100
51,300
57,700
14,500
14,500
85,900
212,000
56,000
—
43,200
6,400
Cal cul ated
Average
Vol ume , SV
(mill ion
gal/yr)
57
25
91
14
39
19
21
5
5
—
—
—
—
—
__
Estimated
Average Solids
Concentration,
SS
2%
4%
0.5%
3,0%
3.6%
5%
5%
18%
18%
3,600 mg/1
560 mg/1
3,000 mg/1
—
5,500 mg/1
* Example is developed for a treatment plant with a wastewater flow of 20 mgd.
20
-------
The following three equations will be useful for estimating a mass bal-
ance:
Dry sludge solids produced per day:
DSS jSV) (SSMSSG) (8.341 (Eq. 2-1)
where
DSS = Dry sludge solids produced per day, Ib/day.
SV = Daily sludge volume, gal /day.
SS = Sludge suspended solids concentration, percent.
SS6 = Sludge specific gravity, unit! ess.
8.34 = Conversion factor, Ib/gal (for water).
Specific gravity of combined sludge solids after mixing two sludge
streams: ;
cpfi - • _____ , _ ____ _.JJL1. (Fct 9-2}
(PSA) + (IUU - ltM* c ;
(100) (SPAT (100) (SPB)
where ;
I
SPG = Combined sludge solids specific gravity, unit! ess.
PSA = Percentage of Sludge A solids in combined sludge solids, percent.
SPA = Specific gravity of !siudge A solids, unitless.
SPB = Specific gravity of Sludge B solids, unitless.
Sludge specific gravity:
SSG = • (SS) (100) - (SST (Eq' 2"3)
(100) (SPG) (100)
where :
SSG = Sludge specific grav.ity, unitless.
SS = Sludge suspended solids concentration, percent.
SPG = Sludge solids specific gravity, unitless.
Sludge volume and sludge boncentrations determined in this mass balance
example (Table 2-3) were calculated using the assumptions listed with the
individual process calculations.
2.4.1 Raw Primary Sludge (Stream A).
Assumptions:
* Sludge volume = 156,000 gal /day.
• Solids concentration = 2 percent.
t Primary sludge specific; gravity = 1.0 (from Eq. 2-3).
21
-------
2.4.1.1 Dry solids produced per day (Eq. 2-1).
DSS = (156,000) (2M1.0) (8.34) = ^^ 1 b/day
2.4.2 Gravity Thickening.
Assumptions:
• Solids capture = 90 percent.
• Effluent solids = 4 percent.
t Influent sludge specific gravity = 1.0 (from Eq. 2-3).
2.4.2.1 Solids Captured (Stream B), DSS.
DSS = (26>°(y0) =23,4001 b/day
2.4.2.2 Sludge Volume (Stream B) (Eq. 2-1).
SV = ,» = 70 100
(8.34) (4) (1.0) /u»iuu
= 25 x 106 gal/yr
2.4.2.3 Side Stream Return (Stream M).
Assumptions:
t Solids = 26,000 - 23,400 = 2,600 1 b/day.
t Flow rate = 156,000 - 70,100 = 85,900 gal /day.
Solids Concentration = /'onh ii°Sl\ = °'36 percent
in side stream return (85,900) (8.34)
= 3,600 mg/1
2.4.3 Waste Activated Sludge (Stream C).
Assumptions:
t Sludge volume = 250,000 gal /day.
• Sludge solids concentration = 0.5 percent.
t Specific gravity of dry sludge solids = 1.25.
• Influent sludge specific gravity = 1.0 (from Eq. 2-3).
2.4.3.1 Total Dry Solids (Eq. 2-1).
DSS = (250'°00) (5(1-0) (8'34) = 10,400 1 b/day
22
-------
2.4.4 Dissolved Air Flotation Thickening.
Assumptions:
• Solids capture = 90 percent.
• Effluent solids = 3 percent.
• Waste activated sludge specific gravity = 1.0 (from Eq. 2-3)
2.4.4.1 Solids Captured (Stream D).
DSS = <10'|y0) = 9,400 Ib/day
i
2.4.4.2 Sludge Volume (Stream D) (Eq. 2-1).
= 14 x 106 gal/yr
2.4.4.3 Side Stream Return (Stream N).
Assumptions:
• Solids = 10,400 - 9,400 = 1,000 1 b/day.
• Flow rate = 250,000 - 38,000 = 212,000 gal /day.
Percent Sol ids = (o(834) = °'056%
, = 560 mg/1
2.4.5 Combined Sludge (Stream E).
2.4.5.1 TDSS = 23,400 + 9,400 = 32,800 1 b/day.
2.4.5.2 SV = 70,100 + 38,000 = 108,100cgal /day
= 39 x 10b gal/yr.
2.4.5.3 Solids concentration.
ss = (32,800) nog) =
(108,100) (8.34) °'°*
2.4.5.4 Determine specific gravity of sludge solids.
Assumptions:
• Specific gravity of primary sludge solids, SPA = 1.4.
• Specific gravity of waste-activated sludge solids, SPB = 1.25.
! 23
-------
_ (23,400) (100) _
r;>rt (32,800) *
Using Eq. 2-2:
SPG = 71.3 (100 - 71.37 1%35
(100) (1.4) (100) (1.25)
where
PSA = Percentage of primary solids in combined sludge solids, percent.
SPG = Specific gravity of sludge solids, unitless.
2.4.5.5 Determine specific gravity of sludge.
SSG (3.6) ^ (100 - 3T6T " lt01
(1.35) (100)
where
SSG = Sludge specific gravity, unitless.
2.4.6 Anaerobic Digestion.
Assumptions:
• Volatile solids = 60 percent.
• Volatile solids destroyed = 50 percent.
• Digested sludge solids concentration = 5 percent.
• Supernatant solids = 0.3 percent (3,000 mg/1).
• Specific gravity of digested sludge solids = 1.4.
2.4.6.1 Solids destroyed (Stream Q) = (32,800) (0.60) (0.50)
= 9,800 Ib/day.
Remaining solids = 32,800 - 9,800 = 23,000 1 b/day.
2.4.6.2 Calculate total mass input to digester (solids + water).
(108,100) (1.01) (8.34) = 910,600 1 b/day
2.4.6.3 Mass output less solids destroyed.
910,600 - 9,800 = 900,800 1 b/day
24
-------
2.4.6.4 Determine the flow rate distribution between the supernatant
at 0.3 percent solids and digested sludge at 5 percent
solids. Let S = 1 b/day of supernatant suspended solids
(Stream P).
S -JIM). + (23,000 - S) (100) =
U» -j 0
333S + 460,000 - 20S = 900,800
31 3S » 440,800
S - 1,400 1 b/day
2.4.6.5 Supernatant flow rate (Stream P).
• 5MO°
where
Q = Flow rate, gal /day.
2.4.6.6 Digested sludge withdrawal (Stream F).
DSS « 23,000 - 1,400 = 21,600 1 b/day
2.4.6.7 Digested sludge specific gravity (Eq. 2-3).
SSG =
(5) (100) - (5)
(100) ;(l-4) (100)
2.4.6.8 Digested sludge volume (Stream F).
I
= 19 x 10^ gal/yr
2.4.7 Chemical Conditioning (Stream S).
Assumptions:
t Lime dosage = 300 Ib/ton of dry sludge.
• Lime feed solution contains 0.5 Ib 1 ime/gal.
25
-------
2.4.7.1 Daily lime requirement.
TDSS = 21,600 + 3,200 = 24,800 Ib/day (Stream G)
2.4.7.2 Flow rate of liquid lime feed system.
Q = ^ = 6,400 gal /day
SV = 51,300 + 6,400 = 57,700 gal /day (Stream G)
21 x 106 gal/yr
2.4.7.3 Sol ids concentration..
<;<; (24,800) (100) _ , 9 ~ (57,700) (8.34) " °*^
2.4.8 Centrifuge dewatering.
Assumptions:
• Solids capture = 92 percent.
• Effluent solids = 18 percent.
2.4.8.1 Solids captured (Stream H).
(24,800) (0.92) = 22,800 1b/day
2.4.8.2 Sludge specific gravity (Eq. 2-3).
SGS = (18) (loo -1ST = 1'05
(1.40) (100) (100)
2.4.8.3 Sludge volume (Stream H), SV.
5 x 106 gal/yr
26
-------
2,4,8.4 Dewaterlng centrate return volume (Stream R).
Volume = 57,700 - 14,500 = 43,200 gal /day
2.4.8.5 Dewatering centrate return solids (Stream R).
24,800 ^22,800 = 2,000 1 b/day
I
i
2.4.8.6 Solids concentration (Stream R).
or 5>500
2.4.9 Hauled dewatered sludge.
One hundred percent of dewatered sludge from the centrifuge process will
be truck-hauled and disposed by application to cropland. Stream I = Stream H.
Flow volumes and sludge solids estimated above are tabulated in Table 2-
3. Note how the sludge volume and solids concentration changes entering suc-
cessive treatment process steps. !
After completing a table similar to Table 2-3, the manual user may go to
the cost curves or algorithms and estimate the base capital cost and base
annual O&M cost of each process in the sludge management chain, as exemplified
in Section 2.8 of this user's guide.
i
2.5 Importance of Assumptions Lasted on Cost Curves
2.5.1 Capital cost curves.
The user should pay close attention to the assumptions listed on the cost
curves. In the base capital cost curves particularly, note the assumptions
for hours per day and days per week of operation which for many processes are
8 hr/day and 7 days/week. Larger treatment plants often operate processes 16
or 24 hr/day. If the process for which cost estimates are being made will
operate more hours per day than the assumption shown on the cost curve, the
capital cost must be adjusted accordingly. This adjustment is made by moving
down on the curve by cal cul ati ng an annual si udge vol ume for a process operat-
ing under the conditions noted on the curve at an equivalent design capacity.
For example, Figure 5-4 shows the base capital cost for a belt filter
press dewatering process which is operating a total of 56 hr/week (8 hr/day, 7
days/week). The base capital cbst for a belt filter press with an annual
sludge volume of 50 million gal/yr at 2 percent solids under this operating
schedule is $0.95 million. If, instead, it is planned to operate the dewater-
ing process a total of 140 hr/week (20 hr/day, 7 days/week), the capital cost
derived from the curve using the annual sludge volume directly is too high.
1 27
-------
An equivalent design capacity is obtained by lowering the sludge volume by a
ratio of 8:20 (i.e., multiply the annual sludge volume, 50, by 0.4 = 20 mil-
lion gal/yr). The base capital cost is then estimated using the cost curves.
In this example, the base capital cost would then be $0.46 million.
For processes operating on a 24-hr/day schedule, costs include standby
equipment and tankage necessary for safe operation during shutdown for clean-
Ing and maintenance. However, for processes assuming 8-hr/day operation such
as dewatering, little or no standby equipment is included, since two-shift
operation following a shutdown can effectively compensate for a unit out of
service. Standby equipment required is highly variable depending on site-
specific operating conditions, reliability of process considered, storage
availability, operating capability, and operating philosophy of the owner.
Therefore, the user should include standby capacity or storage (Section 11)
when adjusting costs from processes assuming an 8-hr/day operation to 24-hr/
day operation.
Land costs are included in the base capital cost curves for those pro-
cesses for which land is a major capital cost element. Process capital cost
curves which include land costs (as noted in the assumptions section of each
curve) are:
Sludge Drying Beds.
Composting - Aerated Static Pile Method.
Composting - Windrow Method.
Land Application to Dedicated Disposal Sites.
Land Disposal to Sludge Landfill.
Sludge Storage - Facultative Lagoons.
Storage of Dewatered Sludge in Unconfined Piles.
For these processes, capital costs include land at $3,120 per acre.
Adjustments to capital costs for locations which have actual land costs dif-
ferent from those assumed can be accomplished using the procedures presented
in each respective cost curve section.
Land costs are not included in the curve capital costs for the remaining
processes. However, the cost algorithms for some processes do contain provi-
sions for calculating the cost of land if it is applicable to the specific
case being examined. These processes are:
t Land Application to Cropland.
» Land Application to Forest Land Site.
• Land Application to Marginal Land for Land Reclamation.
If desired, the cost of land for these unit processes may be added to the
curve capital costs by using the procedure presented in Section 10.
2.5.2 O&M cost curves.
For each process covered in this manual, there is a total O&M cost curve
as well as O&M requirement curves for each component (labor hours, electrical
energy, fuel, and chemicals) included in the O&M cost. The total base annual
28
-------
O&M curve is based on the assumptions noted with each curve. The assumptions
consistently use these unit costs:
o Labor rate = $13.50/hr.
9 Electrical energy cost = $0.094/kWhr.
o Fuel = $1.35/gal.
If the locale where the cost estimates are being made has unit costs sub-
stantially different from the assumed costs, the user may utilize the indivi-
dual component curves to estimate total O&M costs. In order to obtain the
annual O&M component cost, the requirements obtained when using the curve must
be multiplied by the appropriate local unit cost. Note that some components
such as annual replacement parts and materials are given directly in annual
cost. Total base annual O&M cost for each process is obtained by summing the
individual annual O&M component costs.
For instance, the base annual O&M cost shown in Figure 5-5 for a belt
filter which processes 80 million gal/yr at 6 percent solids is $180,000/yr,
based on a labor cost of $13.50/hr and an electrical energy cost of $0.094/
kWhr. However, if the local labor rate is $12.00/hr and electrical energy is
$0.05/kWhr, the total base annual O&M cost is obtained using the component
curves (Figure 5-6) as follows:
o Annual cost of labor = 7,500 hr/yr x $12.00/hr = $90,000.
o Annual cost of electrical energy = 3.4 x 100,000 kWhr/yr x $0.06/kWhr
= $20,400.
o Annual cost of replacement parts and materials = $50,000.
9 Total base annual O&M cost = $160,400.
However, to arrive at total project costs and total O&M costs, certain costs
should be added as described in Section 2.6.
2.6 Total Project Cost
2.6.1 Adjusting costs to account for inflation.
Costs obtained with the base capital and base annual O&M cost curves in
this manual are based on last! quarter 1984 costs, and must be adjusted for
inflation for use in later years. Note that costs obtained using the algo-
rithms in Appendix A afe internally adjusted for inflation. Moreover, when
using the annual O&M component curves described in Subsection 2.5.2, only
those components given directly in dollars per year (such as annual replace-
ment parts and materials) need to be adjusted for inflation, assuming that
current unit costs are used.
Costs are adjusted for inflation using the Engineering News Record Con-
struction Cost Index (ENRCCI),• as shown in Table 2-4 for total base capital
costs and Table 2-5 for total base annual O&M costs. Costs derived with the
algorithms are updated internally using a combination of the ENRCCI and the
Marshall and Swift Equipment Cost Index (MSECI). The ENRCCI appears weekly in
Engineering News Record, McGraw Hill, Inc. The MSECI is available from
29
-------
TABLE 2-4
DEVELOPMENT OF TOTAL CAPITAL COSTS
A. Sludge management process TBCC costs derived in this manual
Process 1 $
Process 2
Process 3
Process 4
Subtotal A
B. Conversion of Subtotal A from fourth quarter 1984 values to inflated
costs at midpoint of construction period using the Engineering News
Record (ENR) Construction Cost Index. Not necessary when using algo-
rithms to calculate TBCC costs (Subtotal A = Subtotal B).
Estimated ENR construction cost index at midpoint of construction
period » current ENR index = .
Divide current ENR index above by 4,171 = ENR index ratio =
Multiply ENR index ratio x Subtotal A = Subtotal B =
C. Add nonconstruction costs to Subtotal B
Engineering design @ 10%* of Subtotal B = $
Construction supervision § 5%t of Subtotal B - $
Legal and administrative costs § 20%* of Subtotal B = $
Contingencies @ 15% of Subtotal B = $
Subtotal C = $
Interest during construction @ current annual interest =
decimal rate x years of estimated construction period x
1/2 = x Subtotal C =
Total estimated capital cost (Subtotal C + Interest)
* Engineering design costs normally range from 7 to 15%.
t Construction supervision costs normally range from 3 to 8%.
30
-------
. TABLE 2-5
DEVELOPMENT OF TOTAL ANNUAL O&M COSTS
A. Fourth quarter 1984 si udge:management process O&M costs derived from the
cost curves or algorithms in this manual.
Process 1 $
Process 2 $
Process 3 $_
Process 4 • $
Subtotal A
B. Conversion of Subtotal A to inflated O&M costs during the first year of
system operation using the ENR index. Conversion not necessary when
obtaining costs from the component curves and algorithms (Subtotal A =
Subtotal B). :
Estimated ENR construction cost index at midpoint of first year of system
operation = current ENR index =
Divide current ENR index above by 4,171 = O&M index ratio =
Multiply O&M index ratio x: Subtotal A = Subtotal B =
C. Add administrative and laboratory costs to Subtotal B
i
Administrative costs @ 20%* of Subtotal B = $
Laboratory costs @ 10%t of Subtotal B = $
Total estimated annual O&M costs for first year
of system operation $
* Administrative costs normal!y|vary from 10 to 30%.
I
t Laboratory costs vary widely depending on the sludge processes used.
Can be 0% to over 30%.
31
-------
Chemical Englneerlng magazine. The Marshall and Swift Index is used to adjust
equipment costs or combined costs In which equipment is the major cost compo-
nent. The remainder of costs are adjusted using the ENRCCI. When developing
total project costs using the algorithms in Appendix A, adjustment for infla-
tion (Step B, Tables 2-4 and 2-5) is not necessary, since the adjustment is
made in the algorithm.
When using the O&M componentL curves, the user can specify unit costs for
most O&M components, thus eliminating the need for inflation adjustment if
current unit costs are used. However, components presented in terms of annual
cost, such as annual replacement parts and maintenance materials, must be
adjusted for inflation using the appropriate index. This adjustment should be
done prior to obtaining a process total O&M cost using an equation such as:
COSTOM = (L) (COSTL) + (E) (COSTE) + (COSTM)
ENRCCI
4,171
where
COSTOM
L
COSTL
E
COSTE
COSTM
Annual cost of operation and maintenance, $/yr.
Annual labor requirement, hr/yr, from component curve.
User-specified cost of labor, $/hr.
Annual energy requirement, kWhr/yr, from component curve.
User-specified cost of energy, $/kWhr,
Annual cost of maintenance, $/yr, from component curve.
When using the O&M component curves and the cost algorithms, inflation
adjustment is not necessary (Step B, Table 2-5); therefore, Subtotal A = Sub-
total B.
2.6.2 Development of total base capital cost estimates.
Total base capital costs (TBCC) for sludge management processes in this
manual include structural, mechanical, equipment, electrical, and instrumenta-
tion costs. They do not include costs for engineering design, construction
supervision, legal and administration, interest during construction, and con-
tingencies. These nonconstruction costs must be estimated and added to the
process TBCC costs derived from the cost curves or cost algorithms in order to
estimate the total project construction cost as shown on Table 2-4.
2.6.3 Development of total annual O&M cost estimates.
The annual O&M cost for sludge management processes in this handbook do
not include costs for administration and laboratory sampling/analysis. These
costs must be estimated and added to the process O&M costs derived from the
cost curves and cost algorithms in order to obtain the total estimated annual
O&M cost, as shown on Table 2-5. Total annual O&M costs will normally be
about 30 percent higher than the O&M costs shown in the cost curves adjusted
for Inflation.
The total estimated O&M cost calculated above does not include revenues
generated through the sale and/or use of sludge, composting products, or
sludge by-products (i.e., methane produced In anaerobic digestion). If the
user has information available on revenues generated through usage or sale,
32
-------
O&M costs may be decreased by subtracting any revenues generated on an annual
basis from the fixed annual O&M 'cost for that process.
2.6.4 Development of total project cost.
Total project cost is obtained by combining the total base capital cost
from Table 2-4 and the total annual O&M cost from Table 2-5. Two approaches
are possible: use of total annual cost or use of present worth. If the total
annual cost concept is to be used, the total base capital cost must be amor-
tized using the appropriate interest rate and time period.
The annual amortized capital cost is calculated as follows:
1. Calculate the capital recovery factor.
(Eq. 2-4)
where .j (1 + i)pp - 1
!
CRF = Capital recovery factor, decimal percent/yr.
i = Interest rate, annual percentage (decimal).
pp = Planning period, yr.
2. Calculate the annual amortized capital cost.
ACC = (CRF) (PC) (Eq. 2-5)
where
ACC = Annual amortized capital cost, $/yr.
PC = Total base capital cost, $ (from Table 2-4).
The annual amortized capital cost is added to the total annual O&M cost
(from Table 2-5) to obtain a total annual project cost. For example, assume a
$5,000,000 project, a $129,000 O&M cost in year 1, 5 percent/yr escalation in
O&M, amortization at a 10 percent interest rate over 20 years (capital recov-
ery factor = 0.11746). The total annual project cost in any year is cal cu-
1 ated as foil ows:
Amortized Capital O&M Cost Total Annual
Year Cost ($/yr) ($/yr) Cost ($/yr)
1 587,300 129,000 716,300
2 587,300 135,500 722,800
3 587,300 142,200 729,500
4 587,300 149,300 736,600
etc. etc; etc. etc.
33
-------
The second method of comparing projects is to use the present worth con-
cept, which brings the annual expenditures for O&M back to present worth. For
the example shown previously, it is necessary to determine the present worth
of the O&M expenditures (increasing at 5 percent annually) over the period of
time under consideration, and to add this to the capital cost. For a 10-year
period of time, the present worth of the annual O&M expenditures, which are
assumed to increase at a rate of 5 percent, is:
Year
1
2
3
4
5
6
7
8
9
10
Amortized O&M
Cost ($/yr)
129,000
135,500
142,200
149,300
156,800
164,600
172,900
181,500
190,600
200,100
Present Worth
Factor* (10%
Interest Rate)
1.000
0.9091
0.8264
0.7513
0.6830
0.6209
0.5645
0.5132
0.4665
0.4241
* Present worth factor =!/(!+ i)n
where
i = Interest rate, decimal percent.
n = Year - 1.
Present Worth on
Annual O&M ($)
129,000
123,200
117,500
112,200
107,100
102,200
97,600
93,200
88,900
84.900
1,055,800
The total base capital cost (obtained from Table 2-4) is then added to
the present worth of the annual O&M expenditures to obtain a total estimated
project present worth. Thus, in this example, the total estimated project
present worth for a 10-year period would be $6,055,800.
The total estimated project cost calculated above does not include sal-
vage values and other items usually considered when performing a present worth
analysis. The user should be aware that the structural and equipment compo-
nents with lives greater than the planning period have a salvage value calcu-
lated using a uniform depreciation over the service life of the equipment.
Land is unique in terms of salvage value in that its value has escalated at a
compounded annual rate of 3 percent. Therefore, the salvage value of land at
the end of the planning period is assumed to be higher than its initial cost.
The total estimated project cost does not include a number of items which
relate to the entire treatment plant. These items include:
• Inter-process piping.
• Standby power.
34
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• Roads, landscaping, and lighting.
t Special subsurface or geological conditions which may require dewater-
ing or pil es. ;
• Administration, laboratory, and maintenance buildings/facilities.
While costs obtained with this manual are suitable for alternative com-
parisons, it is possible that; these components vary between alternatives.
Under these circumstances, it is essential that the cost of these items be
included in the total project cost estimate.
2.7 Calculating Cost Per Dry Ton
In sludge processing, it is often desirable to express costs in terms of
annual cost per dry ton. This cost is obtained by summing the amortized capi-
tal cost and base annual O&M costs (as discussed in Subsection 2.6.4) and
dividing by the annual dry sludge solids processed.
1. Calculate the annual process rate of sludge in dry tons per year.
(SS) (SSG) (8.34)
(100) (2,000)
where
TDSS = Annual dry solids processed, tons/yr.
SV = Sludge vol ume, igal /yr.
SS = Suspended solids, percent.
SSG = Sludge specific gravity, unit! ess.
8.34 = Conversion factor, Ib/gal.
2,000 - Conversion factor, 1 b/ton.
2. Determine the cost per dry ton.
ACC + COSTOM
CPDT =
TDSS
where
CPDT - Cost per dry ton, $/ton.
ACC = Annual amortized capital cost, $/yr.
COSTOM - Base annual O&M cost, $/yr.
If information on salvage values and revenues generated from sludge usage
is available, it can be subtracted from the numerator in the above equation.
2.8 Example Using Cost Curves ,
This subsection presents an example in which the cost curves are utilized
to estimate costs for a proposed si udge management system. Total project cost
is obtained for the same 20-mgd, treatment plant for which the mass balance was
i
; 35
-------
developed in Subsection 2.4. This sludge management scheme, shown schemati-
cally on Figure 2-2, consists of gravity thickening of primary sludge, dis-
solved air flotation thickening of secondary sludge, anaerobic digestion of
combined thickened sludge, centrifuge dewatering of conditioned sludge, de-
watered truck haul, and sludge application to cropland. Refer to Table 2-3
for influent sludge volume and solids concentrations.
2.8.1 Gravity thickening of primary sludge.
• Influent sludge volume = 57 million gal/yr.
• Influent solids concentration = 2 percent.
• Base capital cost from Figure 3-1 = $280,000.
• Base annual O&M cost from Figure 3-2 = $40,000/yr.
2.8.2 Dissolved air flotation thickening of secondary sludge.
• Influent sludge volume = 91 million gal/yr.
• Influent solids concentration = 0.5 percent.
• Base capital cost from Figure 3-4 = $360,000.
• Base annual O&M cost from Figure 3-5 = $58,000/yr.
2.8.3 Anaerobic digestion of combined sludge.
• Influent sludge volume = 39 million gal/yr.
• Influent solids concentration = 3.6 percent.
• Base capital cost from Figure 4-1 = $1,760,000.
• Base annual O&M cost from Figure 4-2 = $140,000/yr.
2.8.4 Chemical conditioning with 1 irne.
Influent sludge volume = 19 million gal/yr.
Influent solids concentration = 5 percent.
Lime dosage = 300 Ib/ton of dry sludge.
Base capital cost interpolated from Figures 6-2 and 6-3 = $160,000.
Base annual O&M cost interpolated from Figures 6-5 and 6-6 =
$170,000/yr.
2.8.5 Centrifuge dewatering.
• Influent sludge volume = 21 million gal/yr.
• Influent solids concentration = 5 percent.
• Base capital cost from Figure 5-1 = $420,000.
• Base annual O&M cost from Figure 5-2 = $56,000/yr.
2.8.6 Dewatered sludge truck haul.
Sludge volume = 5 million gal/yr.
Solids concentration = 18 percent.
Round trip haul distance = 200 miles.
Base capital cost from Figure 9-4 = $900,000.
Base annual O&M cost from Figure 9-5 = $200,000/yr.
36
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2.8.7 Sludge application ;to cropland.
o Sludge volume = 5 million gal/yr.
,o Solids concentration =18 percent.
o Sludge application rate = 5 dry tons/acre (land is not purchased).
o Base capital cost from Figure 10-1 = $170,000.
o Base annual O&M cost from Figure 10-2 = $50,000/yr.
Annual sludge volume, solfids concentration, base capital cost, and base
annual O&M cost for each sludge management process in the proposed scheme are
summarized on Table 2-6. Theitotal capital cost is developed in Table 2-7,
assuming a 1-year constructionjperiod in which the ENRCCI increases by 5 per-
cent. Interest during construction is calculated at 10 percent per year. The
total capital cost from Table 2-7 is estimated to be $6,699,000.
The total annual O&M cost for this example developed in Table 2-8 is
estimated to be $1,002,000. It1 is assumed that the midpoint of the first year
of system operation is 1 year after construction commences, during which
inflation increases at a rate of 5 percent per year.
The total project cost for the first year of operation using the total
annual cost concept, based on a capital cost amortization of 11 percent inter-
est rate over 20 years, is calculated as follows:
1. Capital recovery factor, using Eq. 2-4.
rRF i (0.11) (1 + O.ll)20
~ ~ 9T\
: (1 + O.liru - 1
= 0.126
2. Annual amortized capital cost, using Eq. 2-5.
i
ACC = (0.126) (6,699,000)
- $844,000/yr
3. Total annual cost during first year.
I
844,000 +1,002,000 = $l,846,000/yr
2.9 References ,
1. Process Design Manual for Sludge Treatment and Disposal. Technology
Transfer Series. EPA-625/1-79-011, Center for Environmental Research
Information, Cincinnati, Ohio, September 1979. 1135 pp. (Available from
NTIS as PB80-200546.) |
2. Metcalf and Eddy, Inc. Wastewater Engineering: Treatment, Disposal,
Reuse. Second Edition. McGraw-Hill Book Company, New York, New York,
1979. 920 pp. :
37
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TABLE 2-6
SUMMARY OF BASE CAPITAL AND BASE ANNUAL O&M COSTS
DESCRIBED IN EXAMPLE
SIudge
Average Influent Solids
Sludge Volume, SV Concentration,
Base Capital* Base Annual
Cost from O&M Cost from
Management Process
Gravity Thickening
Flotation Thickening
Anaerobic Digestion
Chemical Conditioning
with Lime
Centrifuge Dewatering
Dewatered SI udge Truck
Haul
Sludge Application to
Crop! and
Total Cost
(million gal/yr)
57
91
39
19
21
5
5
SS (percent)
2
0.5
3.6
5
5
18
18
Curves ($)
280,000
360,000
1,760,000
160,000
420,000
900,000
170,000
4,050,000
Curves ($/yr)
40,000
58,000
140,000
170,000
56,000
200,000
50,000
714,000
* Base capital and base annual O&M costs were obtained using the assumptions listed
in the text.
38
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i TABLE 2-7
DEVELOPMENT OF !TOTAL CAPITAL COSTS FOR EXAMPLE
A. Sludge management process |TBCC costs derived in this manual.
Gravity Thickening $ 280,000
Dissolved Air Flotation Thickening $ 360,000
Anaerobic Digestion | $ 1,760,000
i
Chemical Conditioning \ $ 160,000
Centrifuge Dewatering \ $ 420,000
Dewatered SI udge Truck Ha til $ 900,000
Sludge Application to Cropland $ 170,000
Subtotal A $' 4,050,000
! —________»•_•_______________
|
B. Conversion of Subtotal A from fourth quarter 1984 values to inflated
costs at midpoint of construction period using the Engineering News
Record (ENR) Construction Cost Index. Not necessary when using algo-
rithms to calculate TBCC costs (Subtotal A = Subtotal B).
Estimated ENR construction cost index at midpoint of construction
period = current ENR index = 4,380 .
Divide current ENR index above by 4,171 = ENR index ratio = 1.05
Multiply ENR index ratio x Subtotal A = Subtotal B = 4.253,000
C. Add nonconstruction costs [to Subtotal B
Engineering design @ 10% of Subtotal B = $ 425,000
Construction supervision @ 5% of Subtotal B = $ 213,000
Legal and administrative costs @ 20% of Subtotal B = $ 851,000
Contingencies @ 15% of Subtotal B = $ 638,000
Subtotal C = ! $ 6,380,000
Interest during construction @ current annual interest =
decimal rate x years of estimated construction period x
1/2 = 0.05 x Subtotal C = $ 319,000
Total estimated capital cost (Subtotal C + Interest) $ 6,699,000
39
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TABLE 2-8
DEVELOPMENT OF TOTAL ANNUAL Q&M COSTS FOR EXAMPLE
A. Fourth quarter 1984 sludge management process O&M costs derived from the
cost curves or algorithms in this manual.
Gravity Thickening $ 40,000
Dissolved Air Flotation Thickening $ 58,000
Anaerobic Digestion $ 140,000
Chemical Conditioning $ 170,000
Centrifuge Dewatering $ 56,000
Dewatered Sludge Truck Haul $ 200,000
Sludge Application to Cropland $ 50,000
Subtotal A $ 714,000
B. Conversion of Subtotal A to inflated O&M costs during the first year of
system operation using the ENR index. Conversion not necessary when
obtaining costs from the component curves and algorithms.
Estimated ENR construction cost index at midpoint of first year of system
operation = current ENR index = 4,490
Divide current ENR index above by 4,171 = O&M index ratio = 1.08
Multiply O&M index ratio x Subtotal A = Subtotal B = 771,000
C. Add administrative and laboratory costs to Subtotal B
Administrative costs i 20% of Subtotal B = $ 154,000
Laboratory costs @ 10% of Subtotal B = $ 77.QQQ
Total estimated annual O&M costs for first year
of system operation $ 1.002,000
40
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3. Process Design Manual: Sludge Treatment and Disposal. Technology Trans-
fer, EPA-625/1-74-006, October 1974.
4. Eckenfelder, W. W., Jr., ancl J. S. Chakra, eds. Sludge Treatment. Marcel
Dekker, New York, 1981. 591 pp.
5. Wet Air Oxidation of Chemical Sludges. Research Report No. 12. Environ-
ment Canada. Ottowa, Ontario. March 1973. 79 pp.
6. Water Pollution Control Federation. Sludge Dewatering. Manual of Prac-
tice No. 20. Washington, DJC. 1983. 164 pp.
7. Sludge Composting and Improved Incinerator Performance. Municipal Envi-
ronmental Research Laboratory, Cincinnati, Ohio. 1984. 158 pp.
41
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SECTION 3
RAW SLUDGE THICKENING CURVES
3.1 Introduction
This section presents base capital and O&M curves for two thickening pro-
cesses: gravity and dissolved air flotation (OAF) thickening. Thickening
achieves sludge volume reduction by concentrating the solids at either the
bottom (gravity) or the top (flotation) of the thickener. The residual liquid
is normally returned to the treatment plant while the concentrated sludge is
sent on for further processing and disposal. The principal purpose of thick-
ening is to reduce sludge volume, thereby lowering the cost of subsequent
treatment. Secondary benefits can include sludge blending, sludge flow equal-
ization, and gas stripping.
For preparation of the cost curves, thickeners are assumed to receive
sludge 24 hours/day, 7 days/week. Costs do not include equipment for the con-
trol of odor, often associated with gravity thickening operations.
3.2 Gravity Thickening
Gravity thickening utilizes the difference in specific gravity between
the solids and water to achieve separation. Settling occurs in a tank similar
to a clarifier under relatively quiescent conditions. The process is charac-
terized by four basic settling zones: clarification zone, hindered settling
zone, transition zone, and compression zone. The top layer, or clarification
zone, contains the clear liquid. In the hindered settling zone, the suspended
particles begin moving downward, forming a gradient of increased thickness.
The transition zone is characterized by a decrease in the solids settling
rate. The bottom, or compession zone, is where the thickening of sludge is a
result of liquid being forced out due to the compression of the overlying
solids.
Gravity thickening is commonly used to thicken primary sludge and com-
bined primary and waste biological sludge. Waste biological sludge alone gen-
erally does not thicken well in a gravity thickener. Chemical conditioning of
sludge (see Section 6) is often done prior to gravity thickening to enhance
performance.
Capital and O&M cost and requirement curves presented in Figures 3-1
through 3-3 for gravity thickening were based on the CAPDET program. The
CAPDET algorithm assumes the design of a circular, reinforced concrete tank.
equipped with a slowly revolving sludge collector. Assumptions and input
parameters used in cost development are noted on the curves.
42
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FIGURE 3-1
BASE CAPITAL COST OF GRAVITY THICKENING AS A FUNCTION OF ANNUAL VOLUME
AND RAW SLUDGE SOLIDS CONCENTRATION
Assufflpt1ons:
Solids loading - 12 Ib/ft2/day; operation = 24 hr/day; operation = 7
days/week; effluent solids concentration = influent solids concentra-
tion in percent plus 2 percent; chemical conditioning is not included.
1.0
O
O
z
O
0.1
in
o
O
Q-
<
O
0.01
61 SS
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 3-2
BASE ANNUAL OSH COST OF GRAVITY THICKENING AS A FUNCTION OF ANNUAL VOLUME
AND RAW SLUDGE SOLIDS CONCENTRATION
Assumptions: Design assumptions are the same as for Figure 3-1; labor cost
$13.50/hr; cost of electricity = $0.094/kwhr.
0.1
Ul
a.
ec
o
a
z
o
0.01
o
_i
<
<
CO
0.001
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 3-3
ANNUAL OSM REQUIREMENTS FOR GRAVITY THICKENING AS A FUNCTION OF ANNUAL VOLUME
AND RAW SLUDGE SOLIDS CONCENTRATION
0 10 tO JO »0 SO 60 70 80 90
ANNUM. SLUDGE VOLUME (MILLION CALLOUS Ft* fCAK)
100
0 10 20 }0 to SO tO 70 SO 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
cn
10 10 JO »0 $0 60 70 10 90
AUKtJAt SlUOGI VOLUME (HillION CALLOUS fll. TEAK)
Assumptions:
Design assumptions are
the same as for Figure 3-1
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL REPAIR AND REPLACEMENT-
MATERIALS ESTIMATED AT
U OF CAPITAL COST.
-------
The cost algorithm for this process is presented in Appendix A-l. The
user should consult Appendix A-l for additional information on cost algorithm
development, design parameters, and assumptions used in obtaining costs.
3.3 Dissolved Air Flotation Thickening (DAF)
In dissolved air flotation (DAF) thickening, air is introduced into a
solution that is being held at an elevated pressure. Air can be added either
to the incoming sludge stream, or more commonly, to a separate supernatant
stream that is then combined with the sludge stream at atmospheric pressure.
When the pressure is reduced, minute bubbles of air are formed which attach to
the sludge particles and float to the surface. The sludge blanket is then
removed using a skimmer mechanism.
DAF thickening is generally used for waste biological sludges and com-
bined primary and waste biological sludges. Thickener performance is usually
enhanced substantially by prior chemical conditioning of the sludge (see Sec-
tion 6).
Capital and O&M cost and requirement curves presented in Figures 3-4
through 3-6 for flotation thickening were obtained using the CAPDET program.
Costs assume the design of a circular reinforced concrete tank. Principal
components included in the capital cost are pressurizing pump, air injection
facilities, retention tank, back pressure regulating device, and the flotation
unit. The flotation unit has a surface sludge collector to dispose of the
floated particles, and a bottom sludge collector. Assumptions and input para-
meters used in cost development are noted on the curves.
A cost algorithm for flotation thickening is presented in Appendix A-2.
The user should consult Appendix A-2 for additional information on cost algo-
rithm development, design parameters, and assumptions used in obtaining costs.
46
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FIGURE 3-4
BASE CAPITAL COST OF DISSOLVED AIR FLOTATION THICKENING AS A FUNCTION
OF ANNUAL VOLUME AND RAH SLUDGE SOLIDS CONCENTRATION
Assumptions:
Solids loading = 20 Ib/ft2/day; operation =24 hr/day; operation = 7
days/week; float solids concentration = 4 percent; chemical condition-
ing is not included.
10.0
OL
f
O
ea
z
o
o
o
a.
<
o
UJ
l/l
ca
i.a
0.1
10 20 30 1*0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION DOLLARS PER YEAR)
100
-------
FIGURE 3-5
BASE AHNUAL 08W COST OF DISSOLVED AIR FLOTATION THICKENING AS A FUNCTION
OF ANNUAL VOLUME AND RAH SLUDGE SOLIDS CONCENTRATIONS
Assumptions: Otsign assumptions are the same as for Figure 3-4; labor cost
$13.50/hr; cost of electricity = $O.Q94/kwhr.
1.0
ce
ui
OL
ex.
<
0.1
00
0.01
o
o
x:
lA
O
0,001
10 20 30 kO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 3-6
ANNUAL OSM REQUIREMENTS FOR FLOTATION THICKENING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
o 10 20 30 *e so *o ?a to so
ANNUAL SlUOCt VOLUME (HILLIOB GALLOBS ttA
10 10 JO 40 SO tO 70 Bo 50 100
ANNUAL SLUDGE VOLUME (KILLIOB CALLOUS flU TEAR)
10 20 JO to SO (0 TO $0 90 100
AKHBAl SLUOCC VOLUME (Ml LI ION CALLOUS PER VCAK)
Assumptions: Design assumptions
are the same as for Figure 3-4.
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL REPAIR AND REPLACEMENT
MATERIALS ESTIMATED
AT U OF CAPITAL COST.
-------
SECTION 4
SLUDGE STABILIZATION CURVES
4.1 Introduction
This section presents capital and annual operating and maintenance curves
for five sludge stabilization processes: anaerobic digestion, aerobic diges-
tion using mechanical aeration, aerobic digestion using diffused aeration,
lime stabilization, and thermal conditioning. Thermal conditioning is unique
in that it serves as both a stabilization process and a conditioning process.
Sludges are stabilized to render the sludge less odorous and putrescible,
and to reduce the pathogenic organism content. In addition, anaerobic and
aerobic digestion result in a substantial decrease in suspended solids concen-
tration through the oxidation of the volatile or organic fraction of the
sludge.
Operating conditions assumed when developing cost curves are listed on
each respective curve. Generally, all stabilization processes, with the
exception of lime stabilization and thermal conditioning, are assumed to oper-
ate continuously. Lime stabilization is assumed to operate 8 hours per day,
365 days per year, while thermal conditioning is assumed to operate 20 hours
per day, 365 days per year. None of the processes include land costs, since
they are generally minor compared to the capital cost of the equipment and
structures required.
4.2 Anaerobic Digestion
Anaerobic digestion is a process in which biological degradation occurs
in the absence of free oxygen. The degradation products under these condi-
tions are methane, carbon dioxide, water, and partly degraded intermediate
organics. The solids remaining after digestion are rendered stable, since
little organic matter remains that can sustain further biological activity.
Digested sludges are generally more readily dewatered than undigested sludges.
Capital costs and O&M costs and requirements presented in Figures 4-1
through 4-3 for anaerobic digestion are based on use of the CAPDET program.
The CAPDET algorithm assumes the design of single-stage, low-rate cylindrical
digesters constructed with reinforced concrete. Fuel energy for heating is
supplied by the methane generated during digestion. Capital costs include
excavation and construction of tanks, purchase and installation of floating
cover, gas circulation equipment, external heater and heat exchanger, gas
safety equipment, positive displacement pumps, internal piping, and ancillary
equipment. In addition, capital costs include a two-story control building.
50
-------
FIGURE 4-1
BASE CAPITAL COST OF ANAEROBIC DIGESTION AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
CO
o
a
CO
O
o
Q.
O
LU
CO
CO
Incoming sludge temperature = 70* F; digestion temperature = 95' F;
average ambient air temperature = 40* F; volatile solids = 60 percent;
percent volatile solids destroyed = 50 percent; 24-hour continuous
operation; effluent solids concentration = influent solids concentra-
tion plus 2 percent.
10 20 30 '•O 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION DOLLARS PER YEAR)
-------
FIGURE 4-2
BASE ANNUAL 08H COST OF ANAEROBIC DIGESTION AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assuraptions: Design assumptions are the same as for Figure 4-1; Labor cost =
$13.50/hr; cost of electricity = $0.094/kwhr.
Ul
ro
OL
UI
a.
o
o
CO
o
o
ui 0.01
CD
10 20 30 1»0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 4-3
ANNUAL 05M REQUIREMENTS FOR ANAEROBIC DIGESTION AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
en
CO
0 10 10 JO *0 SO (0 70 BO JO 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
0 10 19 )0 tO SO 60 70 10 90 100
ANNUAL SLUOtt VOLUME (MILLION CALLONS UK UAR)
a 10 it 30 *o so to ;o 10 jo too
ANNUAL SLURCC »OLUMI (MILLION CALLONS PER YEAH)
Assumptions: Design assumptions
are the same as for Figure 4-1
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL MATERIAL AND SUPPLIES
REQUIRED FOR MAINTENANCES.
-------
4.3 Aerobic Digestion
Aerobic digestion is the stabilization of raw sludge under aerobic condi-
tions, similar in principle to the activated sludge process. Sludge solids
are converted to carbon dioxide, water, and ammonia through the microbial
degradation of sludge solids. Oxygen is supplied either by surface aerators
(mechanical aeration) or by diffusers (diffused aeration). Aerobically di-
gested sludges generally have poor mechanical dewatering characteristics.
Capital costs and O&M cost and requirement curves are presented in Fig-
ures 4-4 through 4-6 for aerobic digestion using mechanical aerators, and in
Figures 4-7 through 4-9 for aerobic digestion using diffused aerators. Cost
curves are based on use of the CAPDET program. CAPDET algorithms assume the
design of cylindrical digesters constructed with reinforced concrete. Capital
costs include excavation, construction, and installation of all equipment.
Capital costs for aerobic digestion using mechanical aerators include purchase
and installation of aerators. Capital costs for aerobic digestion using dif-
fused aerators include purchase of diffusers and headers. However, capital
costs do not include the cost of blowers, associated equipment, and blower
building. It is assumed that the air capacity required for digestion would be
provided by a common blower facility serving both the activated sludge process
and diffused aerobic digestion.
4.4 Lime Stabilization
The addition of lime to stabilize sludge (pH >12) results in the destruc-
tion of pathogens and reduction of odor potential. Lime-stabilized sludges
are easily dewatered, and are suitable for application on land (providing the
high pH is not a problem). The process may be used on both raw and digested
sludges. The primary disadvantage of lime stabilization is that no organic
oxidation occurs. If the pH drops below 10, bacteria regrowth may occur,
resulting in the production of noxious odors. A second disadvantage is that
lime addition increases the sludge volumes, often resulting in higher transpor-
tation and disposal costs.
Capital costs and O&M cost and requirement curves are presented in Fig-
ures 4-10. through 4-12 for lime stabilization. Curves are based on the use of
hydrated lime (Ca(OH)2). Capital costs include a lime storage silo sized for
30 days lime storage, dual batch mixing tanks (each having the capacity to
hold 0.5 hours of plant design sludge flow), and a lime feeding system.
4.5 Thermal Conditioning
Thermal conditioning is both a stabilization and conditioning process
which prepares sludge for dewatering without the use of chemicals. The sludge
is heated to temperatures between 290 °F and 410 °F under pressures of 150 to
400 Ib/in with the addition of steam and sometimes air. Sludge is stabilized
due to the hydrolysis of proteinaceous materials and destruction of cells. In
addition, the high temperatures and pressures to which the sludge is subjected
result in the release of bound water, enhancing dewatering.
Capital costs and O&M cost and requirement curves are presented in Fig-
ures 4-13 through 4-15 for thermal conditioning. Capital costs include pur-
chase and installation of the following equipment: sludge feed pumps, sludge
54
-------
FIGURE 4-4
CAPITAL COST OF AEROBIC DIGESTION USING MECHANICAL AERATORS AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assuraptions:
Detention time = 20 days; volatile solids = 60 percent; volatile solids
destroyed = 45 percent; digestion temperature = 73* F; 24-hour continu-
ous operation; effluent solids concentration = 4 percent.
tn
01
O
Q
O
O.
<
O
UJ
vt
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 4-5
BASE ANNUAL OSM COST OF AEROBIC DIGESTION USING MECHANICAL AERATORS AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design assumptions are the same as for Figure 4-4; Labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr.
1 .0
en
en
<
Ld
>•
EC
Ul
Q.
O
o
o
o
z:
i*j
o
•z.
<
LU
Ul
<
CD
0. 1
0.01
10 20 30 ko 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 4-6
ANNUAL O&M REQUIREMENTS FOR AEROBIC DIGESTION USING MECHANICAL AERATORS
AS A FUNCTION OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
0 10 20 )0 to SO to 70 80 90 100
ANNUAL StUOGE VOLUME (Hill ION GALLONS PER YEAR)
o 10 ao )t ks so *o 70 «o so 100
ANNUAL UUDCt VOLUME (MILLION GALLONS UK YEAH)
0 '« 20 30 »0 SO SO 70 80 JO 100
AHIIUAl SLUDSf VOLUMC (HILLION CAILONS PI*
Assumptions: Design assumptions are
the same as for Figure 4-4.
NOTE : THE MATERIAL COST CURVE IS
FOR MAINTENANCE MATERIALS AND SUPPLIES
-------
FIGURE 4-7
BASE CAPITAL COST OF AEROBIC DIGESTION USING DIFFUSED AERATION AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
Detention time = 20 days; volatile solids = 60 percent; volatile solids
destroyed = 45 percent; digestion temperature = 73* F; 24-hour continu-
ous operation; effluent solids concentration = 4 percent.
10
O
O
tn
00
O
O
Q_
<
O
LU
1.0
0.1
10 20 30 4o 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 4-8
BASE ANNUAL 08M COST OF AEROBIC DIGESTION USING DIFFUSED AERATION AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 4-7; labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr.
1.0
en
ID
Of
UJ
o.
_J
o
Q
Z
O
oo
O
1*9
O
0.1
0.01
CD
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 4-9
ANNUAL OSH REQUIREMENTS FOR AEROBIC DIGESTION USING DIFFUSED AERATION
AS A FUNCTION OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
o
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (BILLION GALLONS PER YEAR)
too
10 20 }0 •do SO 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PEH YEAR)
Assumpt ions:
Design parameters are
the same as for Figure 4-7,
NOTE : THE MATERIAL COST CURVE IS
FOR MAINTENANCE MATERIALS AND SUPPLIES
10 10 31 « 50 60 70 80 SO 100
ANNUAL SLUKt VOLUKE (KILLION GALLONS PCX YEAR)
-------
FIGURE 4-10
BASE CAPITAL COST OF LIME STABILIZATION AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
oc
o
z
o
o
CO
Daily operation period = 8 hr/day; annual operation period = 365
days/yr; sludge detention time in mixing tank = 0.5 hr/batch; hydrated
lime content of lime product used = 90 percent; cost of storage silos =
$7.70/cu ft; cost of mixing tanks - $0.83/gal of capacity; cost of Lime
feed system = $15.60/lb of feed eapacity/hr; lime dosage = 0.2 Ib lime/
Ib dry soli ds.
1.0
O.I
0.01
10 20 30 kO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 4-11
BASE ANNUAL 08M COST OF LIME STABILIZATION AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 4-10; cost of lime
$104.00/ton;cost of electricity = $0.094/kWhr; cost of labor =
$13.50/hr.
1 .0
(£.
LU
CL.
o:
o
o
ro
0. 1
o
o
o
_i
<
0.0 1
10 20 30 40 50 60 JO 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 4-12
ANNUAL O&M REQUIREMENTS FOR LIME STABILIZATION AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 4-10.
en
w
10 10 JO 4fi so 10 70 (0 90
ANHUAl UUOGt VOLUnt (HtUIOtt GALLONS PtR YEAR)
~ in'
10 20 ]0 *0 JO 60 70 |g jo 100
AUNUAl SLUOCE VOLUH6 (KILIIOH GALLONS ?E» YEAH)
-------
FIGURE 4-12 (CONTINUED)
Assumptions: Design assumptions are the same as for Figure 4-10.
NOTE : THE MATERIAL COST CURVE IS FOR ANNUAL MAINTENANCE MATERIALS AND
SUPPLIES, ASSUMED TO BE 1.5* OF THE BASE CAPITAL COST.
10°
lo*
o to 20 jo to so so ?o to 90 loo
AKNOAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
0 to 20 }0 40 50 tO 70 80 30 100
ANNUAL SLUDGE VOLUHE (HILLIOK CALLONS CER YEAR}
-------
FIGURE 4-13
BASE CAPITAL COST OF SLUDGE THERMAL CONDITIONING AS A FUNCTION OF ANNUAL VOLUME
Assumpti ons:
Daily operation period = 20 hr/day; reactor pressure = 300 Lb/in g;
reactor temperature = 350* F; detention time in reactor = 15 minutes;
system includes all grinding, pumping, air compression/, and heating.
10
to
O
Q
C7i
tn
1 .0
O
O
I-
Q.
<
O
ui
<
CO
0.1
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 4-14
BASE ANNUAL 08M COST OF SLUDGE THERMAL CONDITIONING AS A FUNCTION OF ANNUAL VOLUME
Assumptions: Design assumptions are the same as for Figure 4-13; Labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr; cost of diesel fuel =
$1.35/gal.
1.0
CTi
CTi
Ul
UJ
a.
o
o
to
o
o
o
_l
<
to
<
CO
d o.i
0.01
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 4-15
ANNUAL O&W REQUIREMENTS FOR SLUDGE THERMAL CONDITIONING AS A FUNCTION OF ANNUAL VOLUME
S 10 20 JO 40 JO 60 70 10 JO 100
ANNUAL SlUBK VOtUNE (flllLION SAllONS PCI TEAK)
0 10 20 }0 *0 58 SO 79 80 90 100
ANNUAL SLUDGE VOLUME (MILLION CALLO»S KR YEAR)
0 10 10 JO 10 SO (0 ?0 80 90 100
ANNUAL SLUDGE VOLUME (HillOK GALLONS PER TEAR)
Assumptions: Design assumptions are
the same as for Figure 4-13.
-------
FIGURE 4-15 (CONTINUED)
Assumptions: Design assumptions are the same as for Figure 4-13.
NOTE : A CHOICE IS NECESSARY BETWEEN FUEL OIL OR NATURAL GAS AS A FUEL
THE MATERIAL COST CURVE IS FOR ANNUAL MAINTENANCE MATERIALS
AND SUPPLIES, ASSUMED TO BE 21 OF THE BASE CAPITAL COST.
oo
10 20 30
-------
grinders, heat exchangers, reactors, boiler, gas separators, air compressors
(if required), decanting tank,' piping, and controls. Costs also include a
single-story building and odor control systems. Systems for treatment of the
supernatant and .filtrate recycle streams are not included. These streams are
normally returned to the main treatment plant after preliminary treatment.
69
-------
SECTION 5
SLUDGE DEWATERINS CURVES
5.1 Introduction
This section presents base capital and annual operation and maintenance
curves for five sludge dewatering processes: centrifuge, belt filter, re-
cessed plate filter press, vacuum filter, and sludge drying beds. The cost of
land (at an assumed $3,000/acre) is included only in the sludge drying beds
capital cost. The other sludge dewatering processes listed are not land-
intensive, and land costs are negligible. All dewatering process costs except
sludge drying beds include the cost of a building to house equipment.
As previously discussed in Section 2.5, the user should carefully note
the "hours per day of operation" in the assumptions noted on the curves. All
dewatering curves in this section assume 8 hr/day operation except sludge dry-
ing beds, which are used continuously. Many treatment plants operate dewater-
ing equipment for two or three shifts daily. If the dewatering unit will be
operated more than 8 hr/day, the annual sludge volume from which the capital
cost is derived should be adjusted downward proportionately, as was described
in Section 2.5.1.
At present (1985), belt filters and solid bowl centrifuges are the mech-
anical devices most commonly selected for dewatering municipal wastewater
sludges. Vacuum filters are rarely installed at new treatment plants today.
Recessed plate filter presses are seldom selected due to their high capital
and operating costs, yet in those cases where a very dry cake (e.g., solids
over 30 percent) is desired or necessary, a filter press can be cost-effec-
tive. Sludge drying beds have been commonly used at small treatment plants
which have land available, and in large treatment plants which have both high
evaporation rates and available land.
5.2 Dewatered Sludge Cake Generated by Various Dewatering Devices
It is beyond the scope of this manual to discuss in detail the dewatering
capabilities of various mechanical dewatering processes acting upon different
types of sludges. As a very general guide, however, the following dewatered
sludge cake percent total dry solids ranges are typical for each dewatering
device acting upon a typical digested mixture of 70 percent waste activated
sludge and 30 percent primary sludge:
t Solid bowl centrifuge: 13 to 18 percent.
• Vacuum filter: 12 to 17 percent.
t Belt filter: 15 to 23 percent.
• Recessed plate filter press: 32 to 40 percent.
70
-------
Sludge drying beds vary : widely in their dewaterlng capabilities, with
sludge cake total dry solids generally ranging from 15 percent up to 45 per-
cent. Sludge type, adequacy |of digestor, climate, presence of underdrains,
and time on the beds are some of the factors which affect performance.
5.3 Chemical Conditioning
Proper chemical conditioning prior to dewatering is extremely important.
Chemical conditioning costs arje not included in the cost curves presented in
this section, but are covered in Section 6.
5.4 Centrifuge Dewatering j
Centrifuge dewatering is ;a process whereby centrifugal force is applied
to promote the separation of solids from the liquid in sludge. The most com-
mon type of centrifuge is the ;solid bowl; cost curves are based on the use of
this type. The process is energy-intensive, but has the advantage of requir-
ing littl e space. j
Capital and O&M costs for: centrifuge dewatering are presented in Figures
5-1 and 5-2, respectively. O&M requirements are given in Figure 5-3. Curves
are based on the algorithm in Appendix A-8 using the assumptions noted on the
curves. ;
i
5.5 Belt Filter Dewatering '
Belt filtration is accomplished using two filter belts on rollers which
run continuously in the same; direction and at the same speed. Sludge is
dewatered as it is conveyed between the belts, where the rollers exert in-
creasing pressure on the sludge. Additional dewatering occurs as a result of
shear pressure as the belts pass over an S-shaped roller configuration.
j
Capital and O&M costs for,belt filter dewatering are presented in Figures
5-4 and 5-5, respectively, O&M requirements are given in Figure 5-6. Curves
are based on the algorithm in Appendix A-9, using the assumptions noted on the
curves. ••
5.6 Recessed Plate Filter Press Dewatering
Recessed plate pressure filters are constructed from a number of parallel
plates. The plate surfaces, which are recessed on both sides of the plates,
are covered with filter cloth.i Sludge is pumped under high pressures into the
void spaces between the plates where a sludge cake forms. Filtrate passes
through the filter cloth, flows out between the cloth and plate surfaces, and
is collected in a common drai'nage port. Sludge continues to be pumped into
each recessed plate until they are filled and the filtrate flow approaches
zero. The feed pump is then ;stopped, the plates are opened, and the sludge
cake falls out. The cycle is then repeated.
Figures 5-7 and 5-8 present capital and O&M costs for recessed plate fil-
ter press dewatering. O&M requirements are given in Figure 5-9. Curves are
based on the algorithm in Appendix A-10, using the assumptions noted on the
curves. I
1 71
-------
FIGURE 5-1
BASE CAPITAL COST OF CENTRIFUGE DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
Operation - 8 hr/day; operation = 365 days/year; costs do not include
chemical conditioning; centrifuge h.p. = approximately 1.25 h.p. per
gpm of sludge flow; discharge SS = approximately 10 to 14 percent.
ro
a:
o
Q
o
_i
m
o
o
UJ
03
10
1.0
0.1
10 20 30 ^0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 5-2
BASE ANNUAL O&M COST OF CENTRIFUGE DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 5-1; Labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr.
00
aC.
LJ
Q-
a:
-------
FIGURE 5-3
ANNUAL OSM REQUIREMENTS FOR CENTRIFUGE OEWATERIN6 AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
It SS-6XJ1
0 10 20 JO to 50 60 ?0 SO JO 100
AHMIMI. SLUOSt VOlUHt (HHLIOd CAllOMS P£* YEAK)
»va£-
0 10 20 30 to 50 60 70 80 90 tOO
ANNUAL SLUDGE VOLUME (NllUOH GALLONS flK TEAK)
Assumptions: Design parameters are
the same as for Figure 5-1
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL MAINTENANCE PARTS
AND MATERIALS.
10 20 30 40 SO 60 ?0 (0 90 100
AKHUAI. SLUDGE VOIUKC (BILLION CALLOUS PER TEAK)
-------
FIGURE 5-4
BASE CAPITAL COST OF BELT FILTER PRESS DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS .CONCENTRATION
Assumptions:
Operation = 8 hr/day; operation = 365 days/year; costs do not include
chemical conditioning; loading rate per meter of belt width is 500
Lb/hr for 2 percent SS, 650 Ib/hr for 4 percent SS, and 800 Ib/hr for 6
percent SS; discharge SS is approximately 18 to 22 percent.
10
00
o
o
en
1.0
GO
o
o
Q.
O
LJ
00
CO
0.1
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 5-5
BASE ANNUAL OSM COST OF BELT FILTER PRESS DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
01
Assumptions;
~ 1.0
cc
<
UJ
<£
UJ
Q.
crt
2 0.1
-------
FIGURE 5-6
ANNUAL OSH REQUIREMENTS FOR BELT FILTER PRESS DEWATERING AS A FUNCTION OF
ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Id 20 30 *0 50 (0 70 80 90 100
ANNUAL ULIDCt VOLUMC (HILLIOH GALLONS PiR »EAR)
10 20 J0 *0 SO 40 70 80 JO IOB
ANNUAL SLUOCE VOLUME (MILLIOK CALLOKS PER t(AK)
Assumptions: Design parameters are
the same as for Figure 5-4,
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL PARTS AND MATERIALS.
10 20 30 to SO (0 70 |o gg 100
AUNUAl SLUOSt VOlUHl SHILltOH GALLON! fin «A»!
-------
FIGURE 5-7
BASE CAPITAL COST OF RECESSED PLATE FILTER PRESS DEWATERING AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
Filter cake solids concentration = 40 percent; filter cake density = 71
Lb/ft5; filter chamber volume = 2 ft3; operation = 8 hr/day; operation
= 7 days/week; costs do not include chemical conditioning.
(£.
<
O
O
z
O
03
Q.
<
O
10 20 30 ^0 50 60 70
ANNUAL SLUDGE VOLUME (MILLION GALLONS
80- -90
PER YEAR)
100
-------
FIGURE 5-8
BASE ANNUAL O&H COST OF RECESSED PLATE FILTER PRESS DEWATERING AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 5-7; Labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr.
1 .0
VD
uj
cc
UJ
a.
CC
<
I'd
O
z
z
<
ui
03
o.i-
0.01
to 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 5-9
ANNUAL OSH REQUIREMENTS FOR RECESSED PLATE FILTER PRESS DEWATERING AS A FUNCTION
OF ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
oo
o
2«5S.
0 10 20 30 HO 50 60 70 80 90 100
ANNUAL SlUOGE VOLUME (MILLION GALLONS PER TEAR)
10'
0 10 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER TEAR)
0 10 20 30 "iO SO 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER TEAR)
Assumptions: Design parameters are
the same as for Figure 5-7,
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL MAINTENANCE PARTS
AND MATERIALS.
-------
5.7 Vacuum Filter Dewatering
In vacuum filtration, a vacuum is applied to a portion of the inside of a
moving filter-medium covered drum, which is partially submerged in sludge.
Solids adhere to the surface of the filter medium, and are removed with a
mechanical scraper as the drum, surface rotates and air pressure replaces the
vacuum. Vacuum filters are sel'dom selected today for new treatment plants due
to their high capital cost, high energy consumption, and inability to produce
as dry a sludge cake as belt filters or centrifuges.
Base capital and O&M costs! for vacuum filtration are presented on Figures
5-10 and 5-11, respectively, figure 5-12 provides O&M requirements. Curves
were obtained from the algorithm in Appendix A-ll, using the assumptions noted
on the curves. '
i
5.8 Sludge Drying Beds |
i
Sludge drying bed dewater^ng is perhaps the simplest dewatering process.
Dewatering occurs by drainage through the sludge mass, and by evaporation from
the surface exposed to air. Drying beds are commonly used in small plants,
since they require little operator attention and skill, and use little energy.
The limitations of this process are that it requires a large land area, re-
quires stabilized sludge to prevent nuisance odors, is sensitive to climate,
and is labor-intensive. ',
Base capital and O&M costs are presented in Figures 5-13 and 5-14, re-
spectively. Figure 5-15 is used in adjusting capital costs to account for
land costs different from those assumed in Figure 5-13. The procedure for
adjusting capital costs is described in Subsection 5.8.1 below. O&M require-
ments are presented in Figure '5-16. Curves were obtained from the algorithm
in Appendix A-12, using the assumptions noted on the curves.
5.8.1 Land Cost Adjustment
Land cost is a significant component of the base capital cost presented
in the cost curves for sludge drying beds. Figure 5-13 includes the purchase
of land at an assumed unit cost of $3,120/acre. Because land costs are highly
variable, the user may wish to| change this unit cost to more accurately esti-
mate local costs. This may bejaccompli shed using the following procedure:
. i , .
Step 1. Calculate the cost of land assumed in the curve cost, CLC, from
the following: ;
CLC = TLAR (3,120)
i
t
where !
CLC = Curve land cost, $.
TLAR = Land area required, acres, obtained from Figure 5-15.
81
-------
FIGURE 5-10
BASE CAPITAL COST OF VACUUM FILTER DEMATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
Dry solids loading = 5 Lb/ft2/hour; dewatered cake solids concentra-
tion = 19 percent; operation = 8 hr/day; operation = 7 days/week; chem-
ical conditioning is not included.
10
o
o
03
a
o
a.
<
CJ
LU
(SI
1.0
0.
10 20 30 kO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 5-11
BASE ANNUAL OSM COST OF VACUUM FILTER DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 5-10; labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr.
O
Q
00
CO
O
O
X
id
o
to
1.0
0.1
0.01
0 10 20 30 *IO 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 5-12
oo
ANNUAL OSH REQUIREMENTS FOR VACUUM FILTER DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
0 10 20 30 to $0 60 70 So 90 100
ANNUAL HUOSt VOLUHE (Hill ION CALLOHS PEA TEAK)
10 20 30 to 50 (0 70 BO 90 100
ANNUAL SLUDGE VOLUME (NILLION CALLONS PER TEAK)
0 10 10 30 to 50 60 70 SO JO tOO
ANNUAL SLUDGE VOLUME (Mill ION GALLON! UK TEAK)
Assumptions:
Design parameters are
the same as for Figure 5-10,
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL PARTS AND MATERIALS.
-------
FIGURE 5-13
BASE CAPITAL COST OF SLUDGE DRYING BED DEWATERINS AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumpti ons:
Drying beds are not covered; land
rate = 15 Lb dry solids/ft2/yr at
at 4 perc
solids/ft
ti oni ng.
10.0
int SS,
:/yr at
28 Lb dry
8 percent
cost = $3,12Q/aere; sludge loading
2 percent SS, 22 Ib dry so lids/ftz/yr
solids/ft2/yr at 6 percent SS, and 33 Ib dry
SS. Costs do not include chemical condi-
CO
en
cc
<
UJ
o;
LU
•OL-
t/1
OH
O
o
1 .0 .-
0.1
o
o
Q.
<
o
<
CQ
0.01
5 10 15 20 25 30 35 *»0 ks
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
50
-------
FIGURE 5-14
BASE ANNUAL OSH COST OF SLUDGE DRYING BED DEWATERING AS A FUNCTION OF
ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
Assumpti ons:
t .0
03
CJI
C£.
<
yj
or
Hi
0.
in
cc.
o
D
2;
O
0.1
H
ts>
O
u
Design parameters are the same as for Figure 5-13; cost of labor
$13.50/hr; cost of electricity = $Q.094/kWhr; cost of diesel =
$1.35/gal.
0.01
0.001
co
to
ANNUAL
20
25
35
50
VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 5-15
AREA REQUIRED FOR SLUDGE DRYING BED DEWATERING AS A FUNCTION OF ANNUAL VOLUME
AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 5-13.
100.0
00
t-U
oc
o
10.0
CJ
<
(£.
O
O
uu
DC
=3
of
DC
—I
<
f-
o
1.0
0.1
5 10 15 20 25 30 35 '•O l»5
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
50
-------
FIGURE 5-16
oo
00
ANNUAL OSH REQUIREMENTS FOR SLUDGE DRYING BED DEWATERING AS A FUNCTION OF
ANNUAL VOLUME AND SLUDGE SOLIDS CONCENTRATION
to5 .
0 5 10 15 20 25 30 35 "iO 45 50
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
2:2
0 5 10 15 20 25 30 35 liO "i5 50
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
Assumptions: Design parameters are
the same as for Figure 5-13,
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL MAINTENANCE PARTS
AND MATERIAL.
0 5 10 15 20 25 30 35 liO 45 50
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
Step 2. Calculate the actual cost of land, CLA, from the following:
CLA| = TLAR (LANDCST)
where i
CLA = Actual cost of land, $.
LANDCST = Actual unit cost of land, $/acre.
Step 3. Adjust the curve capital cost to reflect actual land cost using
the following: ;
ACC>= CCC - CLC + CLA
i
where :
i
ACC = Adjusted cunve capital cost, $.
CCC = Unadjusted curve capital cost, $.
89
-------
SECTION 6
SLUDGE CHEMICAL CONDITIONING CURVES
6.1 Introduction
This section presents base capital and base annual operation and mainte-
nance curves for three sludge chemical conditioning methods: lime addition,
ferric chloride addition, and polymer addition. Capital cost curves do not
include the cost of land, since land area required is negligible.
As previously discussed in Section 2.5, the user should carefully note
the "hours per day of operation" in the assumptions, which is 8 hours/day for
all chemical conditioning processes. Many treatment plants operate chemical
conditioning processes for two or three shifts daily. If the process will be
operated more than 8 hours/day, the annual sludge volume from which the capi-
tal cost is derived should be adjusted downward proportionally, as was de-
scribed in Section 2.5.1.
6.2 Use of Chemical Conditioning
Chemical conditioning may be used in a treatment plant prior to both
sludge thickening (see Section 3) and sludge dewatering (see Section 5). The
types of chemical or chemicals used and dosage applied are a function of sev-
eral variables, including sludge characteristics, the requirements of the pro-
cess following chemical conditioning, and chemical costs. These variables are
determined through laboratory bench-scale or pilot plant testing.
Sludges (particularly biological sludges) are often difficult to dewater
due to the presence of significant quantities of colloids and fines, which are
difficult- to destabilize. The primary objective of conditioning is to in-
crease particle size by combining the small particles into larger aggregates,
and by decreasing hydration, decrease the effects of hydrostatic repulsion,.
Chemical conditioning, therefore, enhances flocculation and dewatering.
6.3 Chemical Conditioning Using Lime
Lime is often used for conditioning sludge due to its slight dehydration
effect on colloidal particles. Moreover, CaCOg, formed by the reaction of
lime and bicarbonate, provides a granular structure which increases sludge
porosity and reduces sludge compressibility, thereby enhancing dewatering.
Base capital and O&M cost curves for chemical conditioning using lime are
presented in Figures 6-1 through 6-6 for sludges of 2, 4, and 6 percent
solids, using various lime dosages in Ib/ton dry sludge solids. O&M require-
ments are given in Figures 6-7, 6-8, and 6-9 for sludges of 2, 4, and 6 per-
cent solids, respectively. The curves are based on the algorithm in Appendix
A-13 using the assumptions noted on the curves.
90
-------
FIGURE 6-1
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL VOLUME
AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
Assumptions: Costs are based on the use of hydrated lime; operation = 8 hr/day,
7 days/week.
I .0
O
a
0.
t/l
O
O
a.
<
o
0.01
10 20 30 ^»0 50 60- 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-2
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL VOLUME
AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
Assumptions:
Costs are based on the use of hydrated Lime; operation = 8 hr/day,
7 days/week.
o
Q
PO
0.1
D-
<
O
UJ
t/>
<
03
0.01
a»LJisa-L.fjfiar
10
20
30
50
60
70
80
90
100
VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-3
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL VOLUME
AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
Assumptions: Costs are based on the use of hydrated Lime; operation = 8 hr/day,
7 days/week.
1 .0
(£>
in
cc
o
o
h-
t/1
o
o
Q.
O
Ul
in
co
0.1
0.01
10 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-4
BASE ANNUAL OSM COST OF CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL
VOLUME AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-1; Labor cost -
$13.50/hr; cost of lime = $Q.052/lb.
^ 1.0
ID
CC
<
UJ
c£.
UJ
CL
in
(£.
O
a
0.1
•£.
O
0.01
<
CD
10 20 30 kO 50 60 70 80 90
ANNUAL SLUDGE VOLUHE (HiLLiON GALLONS PER YEAR)
100
-------
FIGURE 6-5
BASE ANNUAL 08M COST OF CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL
VOLUME AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-2; Labor cost =
$13.5Q/hr; cost of Lime = $0.052/Lb.
en
a:
LL)
Cd
UJ
Qu
o
Q
z
o
1 .0
O
C3
£
u>
O
0.
I/I
<
m
0.01
m.
10 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-6
BASE ANNUAL 08H COST OF CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL
VOLUME AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
Assumptions! Design parameters are the same as for Figure 6-3: Labor cost -
$13.50/hr; cost of lime = $0.052/tb.
<
LU
X
a:
UJ
a.
t/j
DC
o
a
1.0
en
0. 1
o
o
3E
<^
O
0.01
co
10 20 30 40 50 60 70 80 90
SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-7
ANNUAL O&M REQUIREMENTS FOR CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL
VOLUME AND LIME DOSA6E; SLUD6E SOLIDS CONCENTRATION = 2 PERCENT.
0 10 20 • JO «0 50 SO JO 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER TEAR)
Hi.
p
3!
vroruii/l°Jt
10 20 JO 10 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER TEAR)
0 10 30 JO "10 50 60 . 70 BO 90 '00
ANNUAL SlUBSC VOLUME (Hill. ION GALLONS PER TEAR)
Assumptions: Design parameters are
the same as for Figure 6-1
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
-------
FIGURE 6-8
UD
CO
ANNUAL OSM REQUIREMENTS FOR CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL
VOLUME AND LIME DOSAiE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
0 10 20 30 *0 50 60 70 80 90 100
AKNUAL SlUDOt VOLUME (MILLION GALLONS PER YEAR)
10 ZO 30 « 50 60 70 80 90 100
ANNUAL SLUOCt VOLUHt (MILLIOIl CALLONS PER ȣAR)
0 10 JO 30 « SO 60 ?0 80 90 100
ANNUAL SLUOOt ¥01U« UILIIO* GALLONS PER TEAR)
Assumptions; Design parameters are
the same as for Figure 6-2.
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
-------
FIGURE 6-9
ANNUAL O&M REQUIREMENTS FOR CHEMICAL CONDITIONING WITH LIME AS A FUNCTION OF ANNUAL
VOLUME AND LIME DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
lO
10
0 10 20 JO "lO 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
10 20 30 «0 50 60 70 80 30 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
10 20 )o '•O 50 60 70 80 90 too
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
Assumptions: Design parameters are
the same as for Figure 6-3,
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
-------
6.4 Chemical Conditioning Using Ferric Chloride
Ferric chloride is used in sludge conditioning as a colloid destabil izer.
When added to water, ferric chloride hydrolyzes, forming positively charged
ion complexes which neutralize the negatively charged solids, causing aggrega-
tion. In addition, it also reacts with the bicarbonate alkalinity in the
sludge to form hydroxides that act as flocculants.
Base capital and O&M costs for chemical conditioning using ferric chlo-
ride are presented in Figures 6-10 through 6-15 for sludges of 2, 4, and 6
percent solids, using various ferric chloride dosages in Ib/ton dry sludge
solids. O&M requirements are shown in Figures 6-16 through 6-18. The costs
are based on the algorithm in Appendix A--14 using the assumptions noted on the
curves.
6.5 Chemical Conditioning Using Polymer Addition
Polymers are long-chain, water-soluble chemicals which have active sites
for adhering to sludge particle surfaces. Polymers act to destabilize sludge
particles through dehydration, charge neutralization, and aggl omerization of
small particles by bridging between particles. The result is the formation of
a polymer-sludge particle matrix which is easily dewatered.
Figures 6-19 through 6-24 present base capital and O&M costs for chemical
conditioning using polymer addition for sludges of 2, 4, and 6 percent solids,
O&M requirements are given in Figures 6-25 through 6-27. Each figure has
curves for various polymer dosages in 1 b/ton dry sludge solids. The curves
were generated with the algorithm in Appendix A-16 using the assumptions noted
on the curves.
100
-------
FIGURE 6-10
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION OF
ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT,
Assumptions: Costs are based on the use of dry ferric chloride; operation =
8 hr/day, 7 days/week.
o
o
a.
o
LU
(/)
03
1 .0
0.1
0.01
UBS/TOH
IBS/TON
FCD - 50 LBS/TON
10 20 3Q 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-11
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION OF
ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT,
Assumptions: Costs are based on the use of dry ferric chloride; operation =
8 hr/day, 7 days/week.
1.0
o
no
t/i
O
O
•as.
o
O
O
Q-
<
O
IU
t/>
<
co
0.1
0.01
10 20 30 ^0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-12
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION OF
ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT,
Assumptions; Costs are based on the use of dry ferric chloride; operation =
8 hr/day, 7 days/week.
l.O
O
-Q
o
OJ
0.1
o
CJ
CL.
<
O
0.01
10 20 30 kQ 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-13
BASE ANNUAL 08H COST OF CHEMICAL CONDITIONING WITH FERRIC CHLOKIDE AS A FUNCTION OF
ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-10; labor cost =
$13.50/hr; cost of ferric chloride = $0.494/lb.
1.0
o
UJ
LU
0_
to
OL
O
O
o
O
O
TC.
«A5
O
<
LLJ
CQ
0.1
0.01
0 10 20 30 l»0 50 60 JO 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-14
BASE ANNUAL O&M COST OF CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION OF
ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-11; Labor cost =
$13.50/hr; cost of ferric chloride = $0.494/Lb.
10.0
o
tn
LU
t£.
UJ
0.
O
O
2
o
o
o
X.
id
O
UJ
CO
CO
0.1
0.01
0 10 20 30 kO 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-15
BASE ANNUAL O&M COST OF CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION OF
ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-12; Labor cost =
$13.50/hr; cost of ferric chloride = $0.494/lb.
10.0
<
LU
>-
LU
QL
CO
CtL
O
O
o
o
s:
US
O
<
OQ
0.01
10 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-16
•ANNUAL OSM REQUIREMENTS FOR CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION
OF ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
10 70 30 40 JO 60 70 80 90 100
ANNUAL SLUDGE VOLUHE (HILLION GALLONS PER YEAR)
10 20 30
-------
FIGURE 6-17
ANNUAL O&M RETIREMENTS FOR CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION
OF ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
o
00
m 10
30
60 70 BO SO 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
10 20 30
-------
FIGURE 6-18
ANNUAL O&n REQUIREMENTS FOR CHEMICAL CONDITIONING WITH FERRIC CHLORIDE AS A FUNCTION
OF ANNUAL VOLUME AND FERRIC CHLORIDE DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
I
f •••<&•• •
)0 20 JO liO 50 SO 70 80 90 100
AHKUAL SLUOSE VtJLUHt (HILIIOH GALLONS PfR VtftR)
1ZL
0 10 10 JO *0 50 60 70 80 90 100
AKNUAl SlUOCE VOIUME (nllllOH GALLONS P« YEAR)
Assumptions; Design parameters are
the same as for Figure 6-12,
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES,
0 '0 30 30 ItO 50 60 70 80 90 100
ANNUAL SlUDm VOLUHt (HIlirON CAILOHS Pt» tlAR)
-------
FIGURE 6-19
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF ANNUAL
VOLUME AND POLYMER DOSAGE," SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
Assumptions: Operation = 8 hr/day, 7 days/week,
1 .0
Ul
cf.
o
0.1
o
o
D.
<
O
LU
l/l
CQ
0.01
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-20
BASE CAPITAL COST OF CHEMICAL- CONDITIONING WITH POLYMERS AS A FUNCTION OF ANNUAL
VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
Assumptions: Operation = 8 hr/day, 7 days/week
1.0
in
<£.
o
o
o
o
o
0.
<
o
IU
t/J
CO
0.1
0.01
0 10 20 30 40 50 ,60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 6-21
BASE CAPITAL COST OF CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF ANNUAL
VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
Assumptions; Operation = 8 hr/day, 7 days/week.
1.0
in
o
o
in
o
o
a.
<
o
lil
in
to
0. 1
0.01
10 20 30 *»0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-22
BASE ANNUAL OSM COST OF CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF ANNUAL
VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-19; Labor cost =
$13.5Q/hr; cost of polymer = $2.80/lb.
1 .0
CO
a:
UJ
a.
cc
o
o
z
o
t/J
o
o
o
(/)
<
DO
0.1
0.01
0.001
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-23
BASE ANNUAL O&M COST OF CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF ANNUAL
VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-20; Labor cost
$13.50/hr; cost of polymer = $2.80/lb.
c/)
an
o
a
<
LU
1 .0
0,1
0.01
0.001
10 20 30 kQ 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-24
BASE ANNUAL 08H COST OF CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF ANNUAL
VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
Assumptions: Design parameters are the same as for Figure 6-21; labor cost =
$13.50/hr; cost -of polymer = $2.80/lb.
<
UJ
>
DC
LU
D_
Z
O
_J
X
o
O
Z
Z
<
CD
0.01
10 20 30 *»0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 6-25
ANNUAL OSM REQUIREMENTS FOR CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF
ANNUAL VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 2 PERCENT.
0 10 JO 30 *0 50 40 ?0 go JO 100
ANNUAL SLUDGE VOLUME (HIUIO* GALLONS f>ER
77
0 10 20 30 *0 50 60 ?0 80 90 100
ANNUAL SlUOGE VOIURE (MILLION OAllONi PER YEAH)
cn
Assumptions; Design parameters are
the same as for Figure 6-19.
NOTE : THE HATERiAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
'0 20 30 $>0 50 fiO ?0 80 90
ANNUAL SLUOCE VOLUME (MILLION GALLONS PE« YEAR)
-------
FIGURE 6-26
ANNUAL Q&M REQUIREMENTS FOR CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF
ANNUAL VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 4 PERCENT.
\f-£
0 10 20 JO id 50 60 70 BO JO 100
AitHUfti siuodt YOIUME (HIUIOH SAILONS PES YE«R)
0 10 20 JO 10 50 40 70 80 SO 100
AHNUSL SLUOCt VOlUHt (NILIIOK CAHOH5 PER TEAK)
Assumptions: Design parameters are
the same as for Figure 6-20.
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
0 10 20 }0 <<0 SO 60 70 80 30 100
AMHUAl SlUOtl »QIUHI (HIUION 6AUOBS PtR ?f«R)
-------
FIGURE 6-27
ANNUAL OSM REQUIREMENTS FOR CHEMICAL CONDITIONING WITH POLYMERS AS A FUNCTION OF
ANNUAL VOLUME AND POLYMER DOSAGE; SLUDGE SOLIDS CONCENTRATION = 6 PERCENT.
oo
0 10 ZO 30 10 50 60 70 80 90 100
annual smote VOIUM (BIIIIOH MIIONS PER TEAS)
0 10 20 30 kO 50 60 70 BO 90 100
ANNUAL SLUBBE VOLUHE (HIILIOK OWIOHS •>£* Yt««)
Assumptions; Design parameters are
the same as for Figure 6-21.
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
0 10 10 30 liO 50 SO 70 80 90 100
ANNUM SlUDCE VOlUht (HIUION GALLONS PE« TEAR)
-------
SECTION 7
SLUDGE INCINERATION CURVES
7.1 Introduction :
This section presents base capital and O&M curves for the two most com-
monly used methods of incineration: fluidized bed and multiple hearth incin-
eration. Incineration processes can reduce the sludge dry solids to 25 per-
cent of the mass entering the unit through the oxidation of volatiles. These
processes are particularly advantageous at locations where land or ocean dis-
posal of sludges is limited or prohibited.
Incineration is a two-step process consisting of sludge drying and com-
bustion. Due to the large amounts of fuel required for startup, the process
is usually operated continuously.
The disadvantages of sludge incineration include the following:
t Depending on feed sludge concentration, large amounts of fuel may be
required to sustain operating temperatures.
• Highly skilled personnel are required to ensure proper operation.
* Pollution control devices may be necessary to control emissions to the
atmosphere. ;
i
• Relatively high capital and Q&M costs are entailed.
As a result of high capital ancl O&M costs, incineration is not normally used
in treatment plants smaller theln 5 mgd, except in areas where sludge must be
transported over long distancesifor disposal.
Operating conditions assumed when developing costs are noted on the
curves. Generally, incineratiori is assumed to operate continuously 24 hours
per day, 360 days per year, which includes shutdowns for maintenance. Fuel
oil is burned to sustain operating temperatures. Capital costs do not include
land costs, since they are minor compared to the cost of equipment and struc-
tures. :
|
The cost of pollution control devices is not included in capital costs,
since they depend on appl icablei federal , state, and local emission standards,
and type of equipment used. In general, pollution control would raise base
capital costs by 10 to 20 percent.
119
-------
7.2 Fluldized Bed Incineration
Fluldized bed Incinerators utilize a fluidized bed of sand as a heat
reservoir to promote uniform combustion of sludge. Air is injected into the
incinerator at a pressure of 3 to 5 psig to fluidize the bed. Temperatures
are maintained between 1,400 and 1,500 °F using gas or fuel oil as an auxil-
iary fuel.
Dewatered sludge is introduced either above or directly into the sand
bed, and is oxidized as it moves through the bed. Exhaust gases and ash are
carried upward to the top of the incinerator and through air pollution control
devices, usually Venturi scrubbers.
Base capital and O&M curves for fluidized bed incineration are presented
on Figures 7-1 through 7-3. Curves are based on the algorithm in Appendix A-
16, using the assumptions noted on the figures. Additional information on
algorithm development, design parameters, and other assumptions is provided in
Appendix A-16.
7.3 Multiple Hearth Incineration
Multiple hearth incinerators are multi-chambered vertically mounted fur-
naces with hearths located above one another. Within each hearth is a set of
rabble arms used to move the sludge in a spiral pattern around each hearth.
Dewatered sludge is fed onto the top hearth of the incinerator, and is swept
radially towards the center where the sludge drops to the second hearth. The
sludge is then swept spirally to the periphery of the second hearth, and
passes to the next lower hearth. This pattern is continued through subsequent
hearths. As the sludge moves toward the bottom, further oxidation occurs,
yielding an ash which is removed from the bottom, Hot rising gases flow in a
direction countercurrent to the sludge flow, out the top of the furnace, and
through any necessary pollution control devices.
Base capital and O&M curves for multiple hearth incineration are pre-
sented in Figures 7-4 through 7-6. Curves are based on the algorithm in
Appendix A-17, using the assumptions noted on the curves. Additional informa-
tion on algorithm development, design parameters, and other assumptions is
provided in Appendix A-17.
120
-------
FIGURE 7-1
BASE CAPITAL COST OF FLUIDIZED BED INCINERATION AS A FUNCTION OF THE WEIGHT OF
DRY SLUDGE SOLIDS INCINERATED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions:
o
o
z
o
Q.
<
U
ui
m
<
CO
Loading rate = 9 Lb wet sludge/hr/sq ft; operating temperature = 1,100' F;
sludge solids are 70 percent volatile; process operates 24 hours per
day, 360 days per year.
6 9 12 15 18 21 2k
DRY TONS INCINERATED PER DAY
27
30
-------
FIGURE 7-2
BASE ANNUAL O&M COST OF FLUIDIZED BED INCINERATION AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS INCINERATED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 7-1; Labor cost =
$13.50/hr; cost of electricity = $0.094/kWhr; cost of diesel fuel
$1 .35/gal.
10.0
ro
ro
UJ
cc.
Ul
a.
o
o
O
o
CO
<
CO
0.01
9 12 15 18 21
DRY TONS INCINERATED PER DAY
27
30
-------
FIGURE 7-3
ANNUAL O&M REQUIREMENTS FOR FLUIDIZED BED INCINERATION AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS INCINERATED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 7-1
!\3
CO
3 6 9 12 15 t8 21 24 27 30
BUT TONS INCIHERSTeO PI* 0»f
6 9 12 15 18 21 Ik 27 }0
OUT TON} INCINERATED tt* DM
-------
FIGURE 7-3 (CONTINUED)
Assumptions: Design parameters are the same as for Figure 7-1
tSJ
4S.
03 6 J IJ IS
0*1 THUS INCIHEdATED PC* DAT
J *
* '* 15 18 21 24 j, 30
OUT TONS INCINERATED PE« DAY
-------
FIGURE 7-4
BASE CAPITAL COST OF MULTIPLE HEARTH INCINERATION AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS INCINERATED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumpti ons;
Loading rate = 6 Lb «et sludge/hr/sq ft; operating temperature = 1,100'
sludge solids are 70 percent volatile;
process operates 24 hours per day, 360 days per year.
ro
en
CO
o
Qu
<
O
<
CD
6 9 12 15 18 21 2k
DRY TONS INCINERATED PER DAY
27
30
-------
FIGURE 7-5
ro
cy>
BASE ANNUAL OSM COST OF MULTIPLE HEARTH INCINERATION AS A FUNCTION OF THE HEIGHT
OF DRY SLUDGE SOLIDS INCINERATED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions; Design parameters are the same as for Figure 7-4; Labor cost =
$13.5Q/hr; cost of electricity = $0.094/kHhr; cost of diesel fuel =
$1.35/gal.
_ 10.0
a:
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UJ
a.
al
o
a
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<
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1.0
0.1
0.01
9 12 15 18 21
DRY TONS INCINERATED PER DAY
24
27
30
-------
FIGURE 7-6
ANNUAL O&M REQUIREMENTS FOR MULTIPLE HEARTH INCINERATION AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS INCINERATED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design parameters are the same as for Figure 7-4.
ro
03 6 9 12 IS 18 21 24 27 30
DRY TONS INCINERATED PER OAT
-------
FIGURE 7-6 (CONTINUED)
Assumptions: Design parameters are the same as for Figure 7-4.
NOTE : THE MATERIAL COST CURVE IS FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
ro
oo
f-
z_
03 6 9 12 15 18 21 2* 27 30
DRV TONS INCINERATED PER DAV
} 6 9 12 15 18 21
DHY TONS INCINERATED PEK DAV
2? 30
-------
; SECTION 8
SLtlDGE COMPOSTING CURVES
8.1 Introduction
This section presents capital and annual operating and maintenance curves
for two sludge composting methods: (a) windrows and (b) aerated static piles.
Also included are figures for both composting methods which show land area and
O&M requirements as a function of the quantity of dry sludge solids composted
annually. ;
Composting is the thermophilic biological decomposition of organic matter
in sludge to yield a relatively stable humus-like material. Dewatered sludges
are prepared for composting byi mixing with a bulking agent to achieve a solids
content of approximately 40 percent, and a porous structure. The bulking
agent usually helps remove moisture and makes the mixture more manageable.
Typically, previously composted sludge, sawdust, or rice hulls are used as the
bulking agent in the windrow process; and wood chips, rice hulls, or straw can
serve as bulking agents in aerated static pile composting. Previously com-
posted sludge is not a suitable bulking agent for aerated static pile compost-
ing, since a more substantial | bulking agent is required to provide porosity,
which allows air to be drawn 'through the pile. In the windrow process, fre-
quent turning of the windrow jaccomplishes aeration. Therefore, porosity is
not as critical, and the bulking agent choice is more flexible.
j
Approximately 20 to 30 percent of the volatile solids are converted to
carbon dioxide and water. If properly operated, high temperatures achieved
during composting can result in the destruction of virtually all pathogens and
parasites. A potential for regrowth does exist, however. Although volatile
solids and water are removed 'during processing, the total compost volume is
generally greater due to added bulking agent and lower density of the compost
product. '
The cost of land for thej composting facility is included in the capital
cost for both composting processes. The procedure for adjusting the curve
capital costs to account for an actual land cost which is different from that
assumed is presented in Subsection 8.4.
8.2 Windrow Composting ' •
In windrow composting, prepared sludges are spread on paved areas in win-
drows with an approximately triangular or trapezoidal cross sectional area of
35 ft'. Windrows are 300 ft, long, or less for small plants. Windrows are
mechanically turned (daily for the first 2 weeks and three times per week
thereafter) to maintain aerobic conditions over the composting period of about
30 days. \
129
-------
Capital costs, O&M costs, and O&M requirements presented in Figures 8-1
through 8-3 are based on the algorithm presented in Appendix A-18. The algo-
rithm assumes that previously composted sludge is used as the bulking agent.
Additional assumptions used in developing cost curves are noted in Table 8-1,
Detailed information on cost algorithm development, design parameters, and
other assumptions used in obtaining costs is provided in Appendix A-18. The
user should use the algorithm if conditions are significantly different from
the assumptions noted in Table 8-1. A land area requirement curve used for
adjusting capital costs for land costs different from the assumed value
($3,120/acre) is provided in Figure 8-4,, The procedure for adjusting capital
costs is presented in Subsection 8.4,
8.3 Aerated Static Pile Composting
Aerated static pile composting is similar in principle to windrow com-
posting. However, in the aerated static pile process, the mixture of de-
watered sludge and bulking agent remains stationary; aerobic conditions are
maintained using a blower system.
Capital costs, O&M costs, and O&M requirements presented in Figures 8-5
through 8-7 are based on the algorithm presented in Appendix A-19, The algo-
rithm assumes that wood chips are used as the bulking agent. Additional
assumptions used in developing cost curves are noted in Table 8-2. Appendix
A-19 contains information on cost algorithm development, design parameters,
and other assumptions used in obtaining costs. The user should use the algo-
rithm if conditions are significantly different from the assumptions noted in
Table 8-2. A land area requirement curve used for adjusting capital costs for
land costs different from the assumed value is presented in Figure 8-8.
8.4 Land Cost Adjustment
Because a significant land area is usually required for composting facil-
ities, it is assumed that new land will need to be purchased by the municipal-
ity. For this reason, the capital costs presented in the curves for these
unit processes include the cost of land at an assumed unit cost of $3,120 per
acre. Because land costs are highly variable, the user may desire to change
this unit cost and, hence, the unit process capital cost to more accurately
fit local costs. This may be accomplished using the following procedure:
Step 1. Calculate the cost of land assumed in the curve cost, CLC, from the
f ol 1 owi ng:
CLC « TLAR (3,120)
where
CLC = Curve land cost, $.
TLAR - Land area required, acres, obtained from Figure 8-4 or 8-8 as
appropriate.
3,120 = Assumed curve land cost, $/acre.
130
-------
FIGURE 8-1
BASE CAPITAL COST OF WINDROW SLUDGE COMPOSTING AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS COMPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design assumptions are listed on Table 8-1.
6 9 12 15 18 21 24
TONS DRY SOLIDS COMPOSTED PER DAY
27
30
-------
FIGURE 8-2
BASE ANNUAL OSM COST OF WINDROW SLUDGE COMPOSTING AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS COMPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design assumptions are listed on Table 8-1.
OJ
ro
LU
in
o
Q
Z
O
O
o
X
*d
o
0.1
6 9 12 15 18 21
TONS DRY SOLIDS COMPOSTED PER DAY
27
30
-------
FIGURE 8-3
ANNUAL O&M REQUIREMENTS FOR WINDROW SLUDGE COMPOSTING AS A FUNCTION OF THE WEIGHT
OF DRY SLUDGE SOLIDS COPIPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION
CO
0 J « 3 12 15 1» 21 24 1J JO
0 i » 5 12 IS 18 21 24 ZJ JO
0 J 6 3 12 li 18 21 2» 27 JO
TONS OUT SOLIDS COHPOSteO PER OUT
Assumptions: Design assumptions are
Listed on Table 8-1.
NOTE : TH£ MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF PARTS
AND MATERIALS.
-------
TABLE 8-1
ASSUMPTIONS USED IN OBTAINING COSTS AND REQUIREMENTS
FOR WINDROW COMPOSTING SHOWN IN FIGURES 8-1 THROUGH 8-4
Parameter
Percent sludge solids in dewatered sludge
Percent volatile solids in dewatered sludge solids
Percent volatile solids destroyed during composting
Percent solids in compost product
Dewatered sludge specific weight
Compost product specific weight
Mixed dewatered sludge and compost specific weight
Windrow cross section
Windrow length
Truck unloading and mixing area
Finished compost storage area
Fraction of site requiring clearing (brush and trees)
Fraction of site requiring light grading
Fraction of site requiring medium grading
Fraction of site requiring extensive grading
Cost of site clearing (brush and trees)
Cost of light grading
Cost of medium grading
Cost of extensive grading
Cost of land
Cost of diesel fuel
Cost of labor
Cost of paving
Assumed Value
20 percent
35 percent
30 percent
65 percent
1,820 lb/yd3
865 lb/yd3
1,685 lb/yd3
35 ft2
300 ft
300 ft2/ton/
day dry solids
900 ft2/ton/
day dry solids
0.7
0.3
0.4
0.3
$l,560/acre
$l,040/acre
$2,600/acre
$5,200/acre
$3,120/acre
$1.35/gal
$13.50/hr
$60,320/acre
134
-------
FIGURE 8-4
AREA REQUIRED FOR WINDROW SLUDGE COMPOSTING AS A FUNCTION OF THE WEIGHT OF DRY
SLUDGE SOLIDS COMPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: Design assumptions are listed on Table 8-1.
100
on
o
o
-------
FIGURE 8-5
BASE CAPITAL COST OF AERATED STATIC PILE SLUDGE COMPOSTING AS A FUNCTION OF
THE WEIGHT OF DRY SLUDGE SOLIDS COMPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions: . Design assumptions are Listed on Table 8-2.
10
00
en
o
0
1.0
o
o
Q.
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VI
m
0. 1
6 9 12 15 18 21 z
TONS DRY SQUIDS COMPOSTED. PER DAY
27
30
-------
FIGURE 8-6
BASE ANNUAL 08M COST OF AERATED STATIC PILE SLUDGE COMPOSTING AS A FUNCTION OF
THE WEIGHT OF DRY SLUDGE SOLIDS COMPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION
Assumptions:- Design assumptions are listed on Table 8-2.
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Q.
Of •
o
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FIGURE 8-7
ANNUAL O&M REQUIREMENTS FOR AERATED STATIC PILE.COMPOSTING AS A FUNCTION OF THE
WEIGHT OF DRY SLUDGE SOLIDS COMPOSTED DAILY AND SLUDGE SOLIDS CONCENTRATION*
CO
02
* 9 1Z 15 18 J! 2*
TONS DRY SOLIDS COMPOSTED PER DAY
2? 30
IL
6 9 IJ 15 IS 21 zk 27
TONS Dltr SOLIDS COMPOSTED n* DAY
30
10'
' } 12 1$ IB 21 H 17 )«
TONS DKY SOLIDS COHPOSUO Flit DAV
Assumptions: Design parameters are
Listed on Table 8-2.
-------
FIGURE 8-7 (CONTINUED)
Assumptions: Design parameters are listed on Table 8-2,
NOTE : THE MATERIAL COST CURVE IS FOR THE ANNUAL COSTS OF PARTS AND MATERIALS
OJ
10
36 * '» IS 18 21 n 27 30
TONS 9*1 SOIIOS tOHPOSTtO ft* »Af
0 ) 6
«5 »» Z1 tk 11 30
TONS OH S8LIBS CONMSteB ftl! OAT
-------
TABLE 8-2
ASSUMPTIONS USED IN OBTAINING COSTS AND REQUIREMENTS
FOR AERATED STATIC PILE COMPOSTING SHOWN IN FIGURES 8-5 THROUGH 8-8
Parameter
Percent sludge solids in dewatered sludge
Percent volatile solids in dewatered sludge solids
Percent volatile solids destroyed during composting
Percent solids in compost product
Compost product specific weight
Mixed dewatered sludge and bulking agent specific weight
Bulking agent mixing ratio
New bulking agent mixing ratio
New bulking agent specific weight
Recycled bulking agent mixing ratio
Recycled bulking agent specific weight
Truck unloading and mixing area
Composting area
Drying area
Finished compost storage area
Bulking agent storage area
Fraction of site requiring clearing
Fraction of site requiring light grading
Fraction of site requiring medium grading
Fraction of site requiring extensive grading
Assumed Value
20 percent
35 percent
45 percent
65 percent
1,000 lb/yd3
1,100 lb/yd3
2.5 yd3/ton
dewatered sludge
0.625 yd3/ton
dewatered sludge
500 lb/yd3
dewatered sludge
1.875 yd3/ton
dewatered sludge
600 lb/yd3
300 ft2/ton/day
dry solids
7,000 ft2/ton/day
dry solids
3,000 ft2/ton/day
dry solids
900 ft2/ton/day
dry solids
2,000 ft2/ton/day
dry solids
0.7
0.3
0.4
0.3
140
-------
Table 8-2 (continued)
Parameter
Cost of site clearing
Cost of light grading
Cost of medium grading
Cost of extensive grading
Cost of land
Cost of diesel fuel
Cos,t of electricity
Cost of labor
Cost of paving
Assumed Value
$l,560/acre
$l,040/acre
$2,600/acre
$5,20Q/acre
$3,120/acre
$1.35/gal
$0.094/kWhr
$13.50/hr
$3.15/ft2
141
-------
FIGURE 8-8
AREA REQUIRED FOR AERATED STATIC PILE SLUDGE COMPOSTING AS A FUNCTION
OF THE WEIGHT OF DRY SLUDGE SOLIDS COMPOSTED DAILY
Assumptions: Design parameters are Listed on Table 8-2.
UJ
cC.
o
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u.
a:
o
a
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cc.
o1
ui
cC.
Ul
a:
100
10
0.1
6 9 12 15 18 21 2^
TONS DRY SOLIDS COMPOSTED PER DAY
27
30
-------
Step 2. Calculate the actual cbst of land, CLA, from the following:
i
CLA = TLAR (UNDCST)
where
CLA = Actual cost ;of land, $.
LANOCST = Actual unit cost of land, $/acre.
Step 3. Adjust the curve capital cost to reflect actual land cost using the
following:
ACC = CCC - CLC + CLA
where
ACC = Adjusted curve capital cost, $.
CCC = Unadjusted curve' capital cost, $.
143
-------
SECTION 9
SLUDGE TRANSPORT CURVES
9.1 Introduction
This section presents capital and annual O&H curves for four commonly
accepted means of sludge transportation: truck hauling, rail hauling, barge
hauling, and pipelines. Truck hauling is further subdivided into (a) liquid
sludge hauling and (b) dewatered sludge hauling. Pipeline sludge transporta-
tion is divided into (a) pipelines and (b) ocean outfalls. Obviously, ocean
outfalls constitute not only a means of sludge transportation3 but also of
disposal.
9.2 Truck Hauling
Truck hauling of sludge is a method of transportation widely used at
small- and medium-size treatment facilities. The principal advantages of
truck transport include its relatively low capital cost when compared with
other modes of transportation, and the flexibility it provides since terminal
points and haul routes can be readily changed.
Capital costs and O&M costs and other requirements are presented in Fig-
ures 9-1 through 9-3 for liquid sludge truck transport, and in Figures 9-4
through 9-6 for dewatered sludge truck transport. Costs and requirements are
based on the cost algorithms in Appendices A-20 and A-21 for liquid sludge
truck transport and dewatered sludge truck transport, respectively. Assump-
tions used in developing cost curves are noted on the curves. Additional in-
formation on cost algorithm development, design parameters, and other assump-
tions can be obtained by referring to the respective appendices.
9.2.1 Capital Cost Multiplication Factor Curve
In the truck haul of sludge, it is assumed that the municipality pur-
chases the haul trucks and has them available regardless of the number of days
per year (DPY) that sludge is hauled. For example, if sludge is hauled only
100 days per year, it is assumed that the haul trucks are idle the remaining
265 days each year. Since all of the sludge generated each year must be
hauled, a decrease in the number of annual days that sludge is hauled requires
that more trucks are purchased; conversely, an increase in the number of
annual days that sludge is hauled requires the purchase of fewer trucks.
The capital cost curves in Figures 9-1 and 9-4 are based on 200 days per
year of sludge truck hauling. To adjust for differences in the number of days
per year that sludge is actually hauled,, the user should multiply the curve
capital cost shown in Figure 9-1 or 9-4 by the appropriate factor taken from
the curves in Figure 9-7.
144
-------
FIGURE 9-1
BASE CAPITAL COST OF LIQUID SLUDGE TRUCK HAULING AS A FUNCTION OF ANNUAL VOLUME
HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions:
Truck Loading time = 0.4 hr; truck unloading time = 0.4 hr; trucks
average 30 mph for 20-, 50-, and 100-mile hauls, 40 mph for 200- and
400-mile hauls; work schedule is 7 hr/day, 200 days/yr (see Figure 9-7
for days per year adjustment factor).
00
<£.
o
Q
-P"
O1
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Q-
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UJ
00
OQ
0 10 20 30 Ao 50 6Q 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS ?ER YEAR)
-------
FIGURE 9-2
BASE ANNUAL O&M COST FOR LI8UID SLUDGE TRUCK HAULING AS A FUNCTION OF ANNUAL VOLUME
HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions: Design parameters are the same as for Figure 9-1; cost of diesel fuel
$1.35/gaL; cost of Labor = $13.50/hr.
~ 10.0
0£
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O.
00
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a
z:
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FIGURE 9-3
ANNUAL O&M REQUIREMENTS FOR LIQUID SLUDGE TRUCK HAULING AS A FUNCTION
OF ANNUAL VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
10 " 3° ""> 50 60 70 80 90 100
ANNUM. SlUOGE VOlUHt (MILLION GALLONS PER YEAR)
10 J0 30 ""> 50 60 70 80 90 100
ANNUAL SLUOOE VOLUME (MILLION GALLONS PER tEAR)
10 20 « »» 50 60 70 (o 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
Assumptions:
Design parameters are
the same as for Figure 9-1.
-------
FIGURE 9-4
BASE CAPITAL COST OF DEWATERED SLUDGE TRUCK HAULING AS A FUNCTION OF ANNUAL VOLUME
HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions:
in
cd
00
CO
O
o
LU
trt
CQ
Truck Loading time = 0.4 hr; truck unloading time = 0.4 hr; trucks
average 30 raph for 20-, 50-, and 100-mile hauls, 40 raph for 200- and
400-ifii le hauls; work schedule is 7 hr/day, 200 days/yr (see Figure 9-7
for days per year adjustment factor); volumetric conversions factor;
1 cu yd = approximately 202 gal.
100
10.0
1.0
.0.1
10 20 30 *tO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PiR YEAR)
100
-------
FIGURE 9-5
BASE ANNUAL 08H COST OF DEWATERED SLUDGE TRUCK HAULING AS A FUNCTION OF ANNUAL VOLUME
HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions
ID
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a.
O
O
H
i/t
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u
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_i
<
z
z
<
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CO
Design parameters are the same as for Figure 9-4; cost of diesel fuel
$1.35/gal; cost of Labor = $13.50/hr; volumetric conversion factor:
1 cu yd = approximately 202 gal.
10.0
1.0
0.1
0.01
10 20 30 kQ 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-6
ANNUAL O&H REQUIREMENTS FOR DEWATERED SLUDGE TRUCK HAULING AS A FUNCTION OF ANNUAL
VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
tn
o
a 10 20 jo to so so jo Bo 90 too
ANNUAL SLUDGE VOLUrtE (MILLION GALLONS PE« TEAK)
10 10 JO « 50 SO 70 80 90 100
ANNUAL SLUDGE VOLURL (MILLION CALLOUS PER TEAR)
Assumptions: Design parameters are
the same as for Figure 9-4,
0 ID 10 }0 kO 50 60 10 Bo 90 100
ANNUAL SLUDGE VOLUHE (BILLION GALLONS PER TEAR)
-------
FIGURE 9-7
CAPITAL COST ADJUSTMENT MULTIPLICATION FACTOR TO ACCOUNT FOR VARYING DAYS
PER YEAR THAT SLUDGE IS HAULED
H W
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=3 =3
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i <
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00 _
1.6
1.5
=3 ,
-s_- 1 .
i.o
0.9
0.8
°-7
0.6
0.5
0.4
0.-3
NOTEsMGY * MILLION GALLONS PER YEAR OF SLUDGE GENERATED
50 75 100 125 150 175 200 225 250 275 300
DAYS PER YEAR THAT SLUDGE IS HAULED (DPY)
-------
For example, assume that the capital cost for hauling 20 million gallons
per year (20-mile round trip) of sludge taken from Figure 9-1 is $570,000,
based on the assumption that sludge is hauled 200 days per year. If sludge is
actually hauled only 100 days per year, the capital cost derived from Figure
9-1 should be increased by the factor of 1.38 shown in Figure 9-7 (i.e., 1.38
x $87,000 = $792,000). Conversely, if sludge is actually going to be hauled
300 days per year, the capital cost derived from Figure 9-1 should be
decreased by the factor of 0.61 shown in Figure 9-7 (i.e., 0.61 x $570,000 -
$348,000).
As shown in Figure 9-7, the cost factors to adjust capital cost for days
per year that sludge is hauled are not significant for very small sludge vol-
umes, but increase or decrease rapidly above 5,000,000 gallons per year of
sludge hauled. The user should estimate cost adjustments by interpolation for
annual sludge volumes other than those shown in Figure 9-7.
9.3 Rail Hauling
Rail transport of sludge can be a cost-effective and energy-efficient
operation when hauling large volumes of sludge over long distances. However,
this mode of transportation has several disadvantages such as: fixed terminal
points; ongoing administration burden; and potential risk of spills due to the
possibility of leaking valves and derailment.
Capital and O&M cost curves for rail hauling presented on Figures 9-8
through 9-14 are based on the cost algorithm presented in Appendix A-22.
Additional information on cost algorithm development, design parameters, and
other assumptions used in obtaining costs is provided in Appendix A-22.
9.4 Barge Hauling
Barge hauling for ocean disposal of liquid sludge has been practiced for
many years. The method has been limited in the past to use by large treatment
plants, since small- and medium-size treatment plants generally do not produce
enough sludge to make barge haul/ocean disposal a cost-effective alternative.
However, through inter-facility pumping to a central facility, several smaller
treatment plants combined can produce enough sludge to make barge hauling a
cost-effective alternative.
The cost curves presented in Figures 9-15 through 9-16 were obtained
using the algorithm in Appendix A-23. Design assumptions used in obtaining
costs are shown on each figure. Additional information on cost algorithm
development, design parameters, and other assumptions is provided in Appendix
A-23.
9.5 Pipe! ine Transport
Pipelines have been used successfully for transporting liquid sludge from
very short distances up to distances of 10 miles or more. The principles
applied in sludge pipeline and water pipeline design are quite similar. How-
ever, the tendency for sludges to adhere to surfaces results in higher ffic-
tional losses which must be accounted for.
152
-------
FIGURE 9-8
BASE CAPITAL COST OF LIQUID SLUDGE RAIL HAULING AS A FUNCTION OF ANNUAL VOLUME HAULED
Assumptions: Rail cars are Leased and their cost is included in annual 6&M cost;
costs in this figure are for loading and unloading facilities only.
CJl
to
ts>
OL
O
a
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o
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o
Q.
<
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1 .0
0.9
0.8
0.7
0.6
0.5
Q.k
0.3
0.2
0.1
10 20 30 kQ 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-9
NORTH CENTRAL AND CENTRAL REGION: BASE ANNUAL 08H COST OF LIQUID SLUDGE RAIL HAULING
AS A FUNCTION OF ANNUAL VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions: Railroad mileage credit = $Q.25/mile; annual rail tank car lease rate =
$9,000/yr; cost of labor = $13.50/hr; cost of electricity = $0.094/kWhr,
10.0
en
UJ
o_
H
ffl
o
o
•£.
"9
O
1 .0
0.1
0.01
10 20 30 1*0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-10
NORTHEAST REGION: BASE ANNUAL 08M COST OF LIQUID SLUDGE RAIL HAULING AS A FUNCTION
OF ANNUAL VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
Assumpt i ons:
Railroad mileage credit = $0.25/mile; annual rail tank car lease rate =
$9,000/yr; cost of labor = $13.50/hr; cost of electricity = $0.09A/kWhr,
100
en
en
t£.
LJ
O_
to
o
o
z
o
I-
V)
o
o
z
z
CO
1.0... Q.
1.0
0.1
0.01
10 20 30 AO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-11
SOUTHEAST REGION: BASE ANNUAL 08M COST OF LIQUID SLUDGE RAIL HAULING AS A FUNCTION
OF ANNUAL VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
Assumpt ions:
Railroad mileage credit = $0.25/mile; annual rail tank car lease pate =
$9,QQO/yr; cost of labor - $13.5Q/hr; cost of electricity = $0.09'4/
kWhr.
10.0
CD
UJ
in
CD
1 .0
<
UJ
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oc
LLl
a.
o
O
o
_]
trt
5? 0.1
0.01
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER Y.EAR)
100
-------
FIGURE 9-12
SOUTHWEST REGION: BASE ANNUAL O&M COST OF LIQUID SLUDGE RAIL HAULING AS A FUNCTION
OF ANNUAL VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions: Railroad mileage credit = $0.25/mile; annual rail tank car lease rate =
$9,000/yr; cost of labor = $13.50/hr; cost of electricity = $0.094/
kWhr.
10.0
01
UJ
cc
UJ
a.
o
o
z
o
o
o
o
_i
<
1 .0
0.1
0.01
10 20 30 AO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-13
WEST COAST REGION: BASE ANNUAL O&M COST OF LIQUID SLUDGE RAIL HAULING AS A FUNCTION
OF ANNUAL VOLUME HAULED AND ROUND TRIP HAUL DISTANCE
Assumpti ons:
en
CO
It!
UJ
a.
o
o
z
o
O
o
05
O
=3
Z
z
CD
Railroad mi.leage credit = $0.25/mile; annual rail tank car lease rate
$9,QQO/yr; cost of labor = $13.50/hr; cost of electricity = $0.0947
kWhr.
_ 100
to.o
RTHD = 100-HILES
0.01
0 10 20 30 40 50 60 JO 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 9-14
en
vo
ANNUAL OSM REQUIREMENTS FOR LIQUID SLUDGE RAIL HAULING AS A FUNCTION
OF ANNUAL VOLUME HAULED
10'
0 10 10 30 *0 SO 60 70 to JO 100
ASKUAL SlUDCE VOLUME (HIUION GAUONS PER YEAR)
0 10 20 JO *0 50 tO 70 80 90 100
AHHUAL SLUDGE VOLime (MILUON 0AUOHS fER YEAR)
Assumptions; Design parameters are
the same as for Figure 9-15.
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF MAINTENANCE
MATERIALS AND SUPPLIES.
0 10 30 30 "iO 50 60 70 BO 90 100
AHMUAt SLUOCE irfllUKE (HIUION GALIOHS PE* TtAB)
-------
FIGURE 9-14 (CONTINUED)
en
o
— 10.0
KORTH CCNTML
10 20 34 do SO 60 70 90 JO 100
ANNUAL SLUDGE VOLUHC (MILLION 6ALLONS PER YEAR)
HOITH EAST
— too
0.01
10 20 JO kO 50 (0 70 80 90 tOO
ANHU*l SlUOOE VOLUHt (NILIION GALLONS PER y|AR)
10 10 JO *0 50 tO 70 80 SO 100
ANNUAL 5LU06I SOLUHI (HILLIOH CAILCKS P£R »£A«)
Assumptions: Design parameters are
the same as for Figure 9-15,
-------
FIGURE 9-14 (CONTINUED)
Assumptions: Design parameters are the same as for Figure 9-15.
Annual rail haul costs are a function of round trip haul distance
and region of the country.
HIST COM!
I 10.0
0 ID 20 30 40 50 (0 70 SO 90 100
ANNUAL SLUDGE VOLUHl (MILLION MUOHS tl* YEAR)
0 10 20 30 <)0 50 60 70 80 90
ANNUAL SLVOGC VOLUME (MIILIOH GALLONS PCR TEAK)
-------
FIGURE 9-15
BASE CAPITAL COST OF LIQUID SLUDGE BARGE HAULING AS A FUNCTION OF ANNUAL VOLUME
HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions:
Average barge speed = 3 mph; barge downtime = 8 hr/tHp; 2 days of sep-
arate sludge storage at Loading facility; 4 hr required to fill barge;
purchase cost of index barge (3,000 liquid ton capacity) = $2,028,000.
too
O
o
PO
to
o
cj
I-
o.
<
o
LLl
(SI
<
CO
20 kO 60 80 100 120 UQ 160 180
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
200
-------
FIGURE 9-16
BASE ANNUAL O&M COST FOR LIQUID SLUDGE BARGE HAULING AS A FUNCTION OF ANNUAL VOLUME
HAULED AND ROUND TRIP HAUL DISTANCE
Assumptions: Design parameters are the same as for Figure 9-15; cost of sludge stor-
age tanks = $0.45/gal of capacity; cost of sludge pumps and piping =
$166/gpm; cost of docking facilities = $52Q,OOQ/barge; cost of tugboat
rental = $360/hr.
100
<
UJ
>-
OL
LU
a.
o
o
o
o
OQ
10
20 l|0 60 80 100 120 Uo 160 180
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
200
-------
Ocean outfalls are a special type of pipeline transportation which con-
stitute both a sludge transportation and disposal method. Ocean outfalls tend
to be more capital-intensive than pipelines due to the environmental condi-
tions under which construction occurs.
Capital and O&M costs and requirements are presented in Figures 9-17
through 9-19 for a 1-mile pipeline; Figures 9-20 through 9-22 for a 5-mile
pipeline; and Figures 9-23 through 9-25 for a 10-mile pipeline. Capital and
O&M costs and requirements for an ocean outfall are presented in Figures 9-26
through 9-28. Cost curves were obtained using the cost algorithm in Appendix
A-24 for pipeline transport and Appendix A-25 for ocean outfall, using the
assumptions shown on each curve. The user should refer to the cost algorithms
for additional information on cost algorithm development, design parameters,
and other assumptions.
164
-------
FIGURE 9-17
BASE CAPITAL
AS
Assumpt i ons:
.o.
a
en
en
a.
<
o
<
CD
COST OF A 1-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP STATION(S)
A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
Hazen-WiILiams friction coefficient = 90; sludge being pumped is
digested with a solids concentration of 4 percent; number of 2- or 4-
lane highway crossings = 1; number of railroad tracks crossed = 1; no
divided highways or rivers crossed; 20 hr/day pumping; fraction of
pipeline length over 6 ft deep = 0.5; no rock excavation required;
costs do not include easement purchase.
1.0
0.1
to 20 30 'tO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-18
BASE ANNUAL OSH COST OF A 1-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP STATION(S)
AS A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
Assumptions: Design parameters are the same as for Figure 9-17; cost of labor =
$13.5Q/hr; cost of electricity = $0.094/kWhr.
as.
<
UJ
OL
Ui
Q-
c£.
O
Q
0.1
en
0.01
0 10 20 30 ^0 50 60 70 80 90 tOO
ANNUAi SLUDGE-VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 9-19
ANNUAL O&H REQUIREMENTS FOR A 1-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP
STATION(S) AS A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
'"* 1
in* -
,»2 .
. .....
. . _
0 F1,
- •
500 F
- 400
. —
T. ElE
n. i
- •
V. OIF
FERENC
LE». OIFFIR
• " "~
"~
t
NCE.
Ol
0 10 20 JO *0 50 60 70 BO 90
*NHU*l SLUDGE VOIUHE (KILLION GALLONS PER TEAR)
'0 20 JO liO 50 60 70 80 90
ANNUAL SLUDGE VOLL/nE (MILLION CAILONS PER YEAR)
i<00
•T.tLE»,lilFFtReH(
0 10 20 JO 40 50 60 70 BO 90 (00
ANNUAL SLUDGE VOIUHE (nlLLIOM GALLONS PER TtAR)
Assumptions: Design parameters are
the same as for Figure 9-17.
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF PUMPING STATION
PARTS AND MATERIALS.
-------
FIGURE 9-20
BASE CAPITAL
AS
Assumptions:
03
t/J
O
O
I-
o_
<
o
LU
(fl
<
to
COST OF A 5-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP STATION(S)
A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
Hazen-WiLLiams friction coefficient = 90; sludge being pumped is
digested with a solids concentration of 4 percent; number of 2- or 4-
lane highway crossings ~ 5; number of railroad tracks crossed = 1; no
divided highways or rivers crossed; 20 hr/day pumping; fraction of
pipeline length over 6 ft deep = 0.5; no rock excavation required;
costs do not include easement purchase.
1.6
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-21
BASE ANNUAL OSM COST OF A 5-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP STATION(S)
•AS A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
Assumptions: Design parameters are the same as for Figure 9-20; cost of labor =
$13.50/hr; cost of electricity = $0.094/kyhr.
cr>
VO
LU
>-
CC
LU
Q.
t/>
02
o
o
•z
•z.
to
<
CD
10 20 30 ftO 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-22
ANNUAL 08M REQUIREMENTS FOR A 5-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP
STATIONCS) AS A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
10 20 JO 40 50 60 70 80 SO 100
ANNUAL SLUDGE VOLUME (MILLION CALLONS PER YEAR)
10 20 JO M 50 60 70 80 90
ANNUAL SLUDCE VOLUHE (MILLION GALLONS PER TEAR)
10 20 JO 10 50 60 70 80 50
ANNUAL SlUBCE VOLUNt (HULION CM10HS PER Yt*ll)
Assumptions:
Design parameters are
the same as for Figure 9-20.
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF PUMPING STATION
PARTS AND MATERIALS.
-------
FIGURE 9-23
Assumpt i ons:
BASE CAPITAL COST OF A 10-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP STATION(S)
AS A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
Hazen-WiILiams friction coefficient = 90; sludge being pumped is
digested with a solids concentration of 4 percent; number of 2- or 4-
lane highway crossings = 10; number of railroad tracks crossed = 2; no
divided highways or rivers crossed; 20 hr/day pumping; fraction of
pipeline length over 6 ft deep = 0.5; no rock excavation required;
costs do not include easement purchase.
2.3
2.2
ce.
o
a
o
o
a.
o
ui
to
CO
2.1
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 9-24
BASE ANNUAL OSH COST OF A 10-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP
STATION(S) AS A FUNCTION OF ANNUAL. VOLUME PUMPED AND ELEVATION DIFFERENCE
Assumptions: Design parameters are the same as for Figure 9-23; cost of Labor
$13.50/hr; cost of electricity = $0.094/kWhr.
ro
UJ
<£
UJ
a.
in
o
o
in
o
o
z:
uS
O
UJ
10
CO
10 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 9-25
ANNUAL 08M REQUIREMENTS FOR A 10-MILE LIQUID SLUDGE TRANSPORT PIPELINE AND PUMP
STATION(S) AS A FUNCTION OF ANNUAL VOLUME PUMPED AND ELEVATION DIFFERENCE
.„*
10 20 }0 *0 SO (0 70 go JO
ANNUAL SLUDGE VOLUME (MILLION CALLOUS PSR UAa)
10 20 }0 *0 50 to JO 88 90
ANNUAL SlUOGC VOLUHE {MILLION GALLONS Pfft TEAR)
U)
0 10 20 30 "id SO 60 70 80 JO 100
ANNUAL SLUOCt VOLUHE (HIUIOK CALLOUS PER YEAR)
Assumptions:
Design parameters are
the same as for Figure 9-23,
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL COSTS OF PUMPING STATION
PARTS AND MATERIALS.
-------
FIGURE 9-26
BASE CAPITAL COST OF A LIQUID SLUDGE OCEAN OUTFALL AS A FUNCTION OF ANNUAL
VOLUME DISCHARGED AND OUTFALL LENGTH
Assumptions:
o
o
CO
Onshore pipeline Length = 2,500 ft; nearshore pipeline Length = 1,000
ft; diffuser pipeLine Length = 500 ft; offshore pipeLine Length is the
indicated outfaLL Length minus 4,000 ft; Hazen-WiLLiams friction co-
efficient = 90; 20 hr/day pumping.
13
12
11
10
9
8
7
6
5
1
30.000 FT. OUTF^
15,000 FT. OUTF^
10.
5,C
ooo F-
)00 FT
r OUTF
kLL LE
\LL LE
\LL LE
. OUTF'ALL L^
i
JGTH
NGTH
NGTH
.NGTH
i
(
i
10 20 30 AO 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 9-27
BASE ANNUAL O&M COST OF A LIQUID SLUDGE OCEAN OUTFALL AS A FUNCTION OF ANNUAL
VOLUME DISCHARGED AND OUTFALL LENGTH
Assumptions: Design parameters are the same as for Figure 9-26; cost of labor
$13.50/hr; cost of electricity = $0.094/kWhr.
en
DC
Ul
DC
Ul
a.
(A
ct
o
Q
to
O
O
UJ
to
CO
0.030
.0.. 025
0.020
0.015
0.010
0.005
5,000-10,000 FT
10 20 30 kO 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 9-28
ANNUAL OSH REQUIREMENTS FOR A LIQUID SLUDGE OCEAN OUTFALL AS A FUNCTION OF
ANNUAL VOLUME DISCHARGED AND OUTFALL LENGTH
1.300
n
t
!
5,000
* JO,
ooo n
OUTF
Ml L^
NCTH
(
,
,
10°
0 10 20 30 to SO 60 70 BO 90 loo
ANNUAL SIUOGE VOLUME (MILLION GALLONS PER YEAR)
0 10 20 30 40 SO 60 70 80 90 100
ANNUAL SLUDGE VOLUHE (MILLION GALLONS PER YEAR)
1.J
Assumpt ions:
Design parameters are
the same as for Figure 9-26,
'0 20 30 liO 50 60 70 SO 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
SECTION 10
SLUDGE APPLICATION TO LAND CURVES
10.1 Introduction !
i
This section presents base capital and annual O&M curves for various
sludge land application programs and sludge landfill operations. Also in-
cluded are procedures for adjusting curve costs to account for variations in
several site-specific variables.. These variables are: days of application
per year, land cost, and costs f,or clearing, grading, and lime addition. Any
adjustment for days of application should be made prior to the other adjust-
ments. i
With all of the methods except land reclamation, sludge is applied at
regular intervals throughout the useful life of the site. The useful life of
the site may be determined by 'various factors, usually the accumulation of
pollutants. For example, with cropland or forest land application, the site
life time ranges from 5 to 20 years, based on a limitation imposed by heavy
metal accumulation.
With land reclamation, the objective is to provide nutrients for estab-
lishing vegetation through a heavy, one-time sludge application. For this
reason, land reclamation costs are based on a one-time application.
10.2 Land Application to Cropland
Use of wastewater treatment' plant sludge as a source of fertilizer nutri-
ent to enhance crop production! is widespread in the United States. Land
application of sludge to cropland affords an environmentally acceptable means
of sludge disposal, while providing the farmer with a substitute or supplement
for conventional fertilizers.
j
Sludge application rates for agricultural utilization are usually low,
i.e., in the range of 3 to 10 tbns/acre/year. Sludges are applied by surface
spreading or subsurface injection. Surface application methods include
spreading by specially equipped 'farm tractors, tank wagons, special applicator
vehicles equipped with flotation tires, tank trucks, and portable or fixed
irrigation systems. Sludge is usually applied only once a year.
Base capital costs, base annual O&M costs, and other O&M requirements for
land application to cropland are presented in Figures 10-1 through 10-3. A
multiplication factor curve to ; adjust for variations in days of application
per year is given in Figure 10-4. Curves are based on the algorithm in Appen-
dix A-26, using the assumptions 'noted on Table 10-1. Appendix A-26 should be
177
-------
FIGURE 10-1
BASE CAPITAL COST OF APPLYING SLUDGE TO CROPLAND AS A FUNCTION OF ANNUAL SLUDGE
VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are Listed in Table 10-1 (see Figure 10-4 to adjust
for difference in days per year of application).
10
OD
z
o
in
o
EX.
<
o
LLl
trt
03
1.0
0. 1
0 10 20 30 *tO 50 60 70 80 SO 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 10-2
BASE ANNUAL O&M COST OF APPLYING SLUDGE TO CROPLAND AS A FUNCTION OF ANNUAL SLUDGE
VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are listed in Table 10-1.
10
LU
ai
UJ
o.
O
O
13
•z.
•z.
<
UJ
<
ca
0.1
0.01
0 10 20 30 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 10-3
ANNUAL OSH REQUIREMENTS FOR APPLYING SLUDGE TO CROPLAND AS A FUNCTION OF ANNUAL
SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
10 20 30 tO 50 (0 70 80 30 100
ANNUAL 51UDCE VOLUHE (MLLION GALLONS PER TEAR)
10 10 JO ' 40 50 SO 70 80 90 100
ANNUAL SLUDGE VOLUHE (HILIION GALLONS m TEAK)
00
o
Assumpt i ons ;
Design parameters are
listed in Table 10-1.
!0 " 10 *o so so 70 so jo loo
AKNUAL SLOBISt VOLUHI {HILLIOK GAUOHS ft* »EA»)
-------
FIGURE 10-4
MULTIPLICATION FACTOR TO ADJUST SLUDGE APPLICATION TO CROPLAND COSTS IN FIGURE 10-1
FOR VARIATIONS IN DAYS OF APPLICATION PER YEAR
Assumptions: Design parameters are Listed in Table 10-1; number of days per xear
that sludge is applied is variable.
5.0
03
DC.
O
ae
O
H
<
O
=3
X
V)
O
O
.UME- (ASV) = 10
rANNUAL^SLUDGE-VO
50 100 150 200 _250 300
NUMBER OF SLUDGE APPLICATION DAYS PER YEAR
350
-------
TABLE 10-1
ASSUMPTIONS USED IN DEVELOPING COST REQUIREMENT CURVES FOR LAND
APPLICATION OF SLUDGE TO CROPLAND
Parameter
Sludge Solids Concentration
Daily Application Period
Annual Application Period
Fraction of Land Required in Addition to
Appl ication Area
Fraction of Land Area Requiring Lime Addition
Fraction of Land Area Requiring Light Grading
Cost of Land
Cost of Lime Addition
Cost of Grading Earthwork
Cost of Operation Labor
Cost of Diesel Fuel
Assumed Val ue
5 percent
6 hr/day
120 days/yr
0.4
0
0
0
0
0
$13.50/hr
$1.35/gal
182
-------
consulted for additional information. In addition, the user should see the
discussion in Appendix A-27 regarding similarities in application costs for
food chain cropland and non-food chain cropland.
10.3 Sludge Application to Marginal Land for Land Reclamation
Sludges have been successfully applied to disturbed or marginal land to
enhance reclamation in Pennsylvania and other states. Disturbed lands consist
of land created as a result of a disturbance such as mining or mineral pro-
cessing operations. Marginal lands are those which sustain little vegetation
such as very sandy and unproductive areas.
Sludge application for land reclamation is usually a one-time applica-
tion, i.e., sludge is not applied again at periodic intervals. Therefore, a
continual supply of land must be provided for application in future years.
Since this algorithm calculates the land required for an annual equivalent
application, the costs of land arid site improvements (clearing, grading, etc.)
are added to the base annual O&M ;cost.
i
i
Sludge application rates v.ary widely, depending on numerous site and
sludge characteristics. Rates reported in the literature vary from 10 to 180
dry tons per acre.
Base capital costs, base ann'ual O&M costs, and other O&M requirements for
sludge application to marginal land are presented in Figures 10-5 through 10-
7. A multiplication factor curve to adjust for variations in days of sludge
application per year is shown in Figure 10-8. Curves are based on the algo-
rithm in Appendix A-28, using the assumptions noted on Table 10-2. Additional
information on algorithm development, design parameters, and other assumptions
is provided in Appendix A-28. >
10.4 Land Application to Forest Land Sites
Application of sludge to forest land has been successfully demonstrated
in the states of Washington, Michigan, and South Carolina. Commercial timber
and fiber production lands, as well as federal and state forests, are poten-
tial application sites for properly managed programs.
Sludge application rates fof forest land application are dependent upon
factors such as sludge characteristics, tree maturity, tree species, and soil
characteristics. Unlike other land application programs which involve annual
sludge application, forest land sludge application to a specific site is often
done at multi-year intervals, e.gl, every 5 years.
Base capital costs, base annual O&M costs, and other O&M requirements are
presented in Figures 10-9 through 10-11. A multiplication factor curve to
adjust costs for variations in days of sludge application per year is given in
Figure 10-12. Curves are based on the algorithm in Appendix A-29, using the
assumptions noted on Table 10-3. The user should consult Appendix A-29 for
additional information.
183
-------
FIGURE 10-5
BASE CAPITAL COST OF APPLYIN6 SLUDGE TO MARGINAL LAND FOR RECLAMATION AS A FUNCTION
OF ANNUAL SLUDGE VOLUME APPLIED
Assumptions: Design parameters are listed in Table 10-2 (see Figure 10-8 to adjust
for differences in days per year of application).
10
in
a:
o
a
1 .0
CO
•p*
O
o
J-
a.
<
o
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to
<
CQ
0. 1
10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 10-6
BASE ANNUAL 08H COST FOR APPLYING SLUDGE TO MARGINAL LAND FOR RECLAMATION AS
A FUNCTION OF ANNUAL SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are Listed in Table 10-2.
00
en
C£.
<
UJ
CC
UJ
Q.
cc
1.0
o
o
I-
to
o
o
<
UJ
OD
0.1
0.01
10 20 30 kQ 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
too
-------
FIGURE 10-7
ANNUAL O&M REQUIREMENTS FOR APPLYING SLUDGE TO MARGINAL LAND FOR RECLAMATION
AS A FUNCTION OF ANNUAL SLUDGE VOLUME APPLIED
Assumptions: Design parameters are Listed in Table 10-2.
00
z
0 10 20 JO 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
0 10 20 }0 *IO 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 10-7 (CONTINUED)
Assumptions: Design parameters are Listed in Table 10-2.
00
-vl
10 20 30 40 SO 60 70 80 30 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
0 10 20 JO 40 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 10-8
MULTIPLICATION FACTOR TO ADJUST SLUDGE APPLICATION TO MARGINAL LAND COSTS
IN FIGURE 10-5 FOR VARIATIONS IN DAYS OF APPLICATION PER YEAR
Assumptions: Design parameters are listed in Table 10-2; number of days per year
that sludge is applied is variable.
5.0
oo
00
cc
o
o
<
u.
z
o
CL
O
O
3.5
3.0
2.5'
2.0
1.5
1 .0
0.5
0.0
ANNUAL SLUDGE VOLUME (ASV) = 5 MGY
'-ASV = 100 MGY
50 100 150 200 250 300
NUMBER OF SLUDGE APPLICATION DAYS PER YEAR
350
-------
; TABLE 10-2
i
ASSUMPTIONS USED IN DEVELOPING COST REQUIREMENT CURVES FOR LAND
APPLICATION 'OF SLUDGE TO MARGINAL LAND
Parameter
Sludge Solids Concentration
i
Daily Application Period
Annual Application Period
Fraction of Land Required in Addition to
Appl i cation Area
Fraction of Land Area Requiring Lime Addition
Fraction of Land Area Requiring Grading
!
Cost of Land
Cost of Lime Addition
Cost of Grading Earthwork
Cost of Operation Labor
Cost of Diesel Fuel
Cost of Monitoring Wells
Assumed Value
5 percent
7 hr/day
140 days/yr
0.3
0
0
0
0
0
$13.50/hr
$1.35/gal
$5,200 each
189
-------
FIGURE 10-9
BASE CAPITAL COST OF APPLYING SLUDGE TO FOREST LAND AS A FUNCTION OF ANNUAL
SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are listed in Table 10-3 (see Figure 10-12 to adjust
for differences in days per year of application).
10
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10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 10-10
BASE ANNUAL O&M COST OF APPLYING SLUDGE TO FOREST LAND AS A FUNCTION OF ANNUAL
SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are Listed in Table 10-3.
10
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ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
1.00
-------
FIGURE 10-11
ANNUAL O&M REQUIREMENTS FOR APPLYING SLUDGE TO FOREST LAND AS A FUNCTION OF
ANNUAL SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are Listed in Table 10-3.
10*
0 10 20 30 *0 50 60 70 80 90 100
ANNUAL SLUOGE VOLUME (MILLION GALLONS PER TEAR)
0 10 20 30 lio SO 60 70 80 90 100
ANNUAL SLUOCE VOLUME (MILLION GALLONS PER TEAR)
-------
FIGURE 10-11 (CONTINUED)
Assumptions: Design parameters are listed in Table 10-3,
10
to
« 10 JO 30 40 50 *0 70 SO 90 100
ANNUM 51UOOE VOlUHt (HIltlOH S*UONS f>E« «»R)
o to 20 30 ''O 50 (o ja to $o too
ANNUAL SLUDGE VOLUHE (Mill ION CAILOH5 fit
-------
FIGURE 10-12
MULTIPLICATION FACTOR TO ADJUST SLUDGE APPLICATION TO FOREST LAND COSTS
IN FIGURE 10-9 FOR VARIATIONS IN DAYS OF APPLICATION PER YEAR
Assumptions: Design parameters are listed in Table 10-3; number of days per year
that sludge is applied is variable.
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3.5
3.0
2.5
2.0
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0.5
0.0
50 100 150 200 250 300
NUMBER OF SLUDGE APPLICATION DAYS PER YEAR
350
-------
TABLE 10-3
ASSUMPTIONS USED IN DEVELOPING COST REQUIREMENT
APPLICATION OF SLUDGE TO FOREST LAND
Parameter
Sludge Solids Concentration
Daily Application Period I
Annual Application Period
Frequency of Application ;
i
Fractior of Land Required in Addition to
Appl i cat ion Area '••
Fraction of Land Area Requiring Cl earing
i
Fraction of Land Area RequiringjGrading
Cost of Land '
Cost of Grading Earthwork !
Cost of Operation Labor
i
Cost of Diesel Fuel
Cost of Monitoring Wells i
Cost of Cl earing :
CURVES FOR LAND
SITE
Assumed Value
5 percent
7 hr/day
150 days/yr
5 yr
0.2
0.05
0
0
0
$13.50/hr
$1.35/gal
$5,200 each
$l,040/acre
195
-------
10.5 Land Application to Dedicated Disposal Site
Land application to a dedicated disposal site differs from other land
application programs in that the site is used primarily or exclusively for the
land spreading of sludge. Sludge application rates are much higher for dedi-
cated disposal sites than for the other land application programs, ranging
from 20 to 200 tons of dry solids/acre/year. Sludge is often applied to a
dedicated disposal site throughout the year, except during inclement weather.
Figures 10-13 through 10-15 present base capital costs, base annual O&M
costs, and other annual O&M requirements for sludge application to a dedicated
disposal site. A multiplication factor curve to adjust capital costs for var-
iations in days of sludge application per year is given in Figure 10-16.
Curves are based on the algorithm in Appendix A-30, using the assumptions
noted on Table 10-4. Additional information is provided for this process in
Appendix A-30.
10.6 Land Disposal to Sludge Landfill
Sludge landfill ing is a disposal process in which sludge is buried by a
layer of cover soil. Cover soil is usually applied daily. This process
should not be confused with co-disposal with municipal refuse or disposal in
which a disposal (tipping) fee is paid. In this process, the sludge-gener-
ating entity owns and operates the landfill for the purpose of sludge dis-
posal .
Base capital costs, base annual O&M costs, and other annual O&M require-
ments for land disposal to a sludge landfill are given in Figures 10-17
through 10-19. Figure 10-20 is used in adjusting capital costs to account for
land costs different from those assumed in Figure 10-17. Curves are based on
the algorithm in Appendix A-31, using the assumptions in Table 10-5. The user
should consult Appendix A-31 for additional information.
10.7 Adjustment of Curve Costs for Land Costs Different from Those Assumed
Base capital cost curves for the application of sludge to croplands., for-
est lands, and marginal lands do not include the cost of land, since these
costs are typically not paid by the sludge generator. However, municipalities
customarily purchase land for dedicated disposal sites and sludge-only land-
fills. Base capital costs presented in curves for dedicated disposal and
sludge landfill processes include the cost of land at an assumed unit cost of
$3,120/acre. The user may want to include land costs for cropland, forest
land, and marginal land application, or use a land cost other than the assumed
unit cost to more accurately fit his particular situation. This may be
accomplished using the following procedure after first adjusting for days of
application, if necessary:
Step 1. For all processes except sludge landfill disposal, refer to Figure
10-21 and use the annual volume of sludge to be applied and the aver-
age sludge solids concentration to determine the weight of dry solids
to be applied annually, TDSS. (Note: For sludge landfill disposal,
total land area required (TLAR), in acres, should be obtained direct-
ly from Figure 10-20. Skip to Step 5.)
196
-------
FIGURE 10-13
BASE CAPITAL COST OF APPLYING SLUDGE TO A DEDICATED DISPOSAL SITE AS A FUNCTION
.OF ANNUAL SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are listed in Table 10-4 (see Figure 10-16 to adjust
for differences in days per year of application).
10.0
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1.0
0.1
10 20 30 kQ 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 10-14
BASE ANNUAL OSH COST OF APPLYING SLUDGE TO A DEDICATED DISPOSAL SITE AS A FUNCTION
OF ANNUAL SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
Assumptions: Design parameters are Listed in Table 10-4.
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SAR = 100 DRY TONS/ACRE
10 20 30 ^0 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
FIGURE 10-15
ANNUAL OSH REQUIREMENTS FOR APPLYING SLUDGE TO A DEDICATED DISPOSAL SITE AS
A FUNCTION OF ANNUAL SLUDGE VOLUME APPLIED AND DRY SOLIDS APPLICATION RATE
10
0 10 20 30 >tO SO 60 70 BO 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS UK TCAIt)
0 10 20 30 >tO SO 60 70 80 90 100
ANNUAL SLUDGE VOLUHE (HIlllON GALLONS PER YEAR)
Assumptions: Design parameters are
Listed in Table 10-4.
0 10 20 )0 l|0 50 60 70 80 90 100
ANNUAL SLUDGE VOLUKE (MILLION GALLONS FED YEAR)
-------
FIGURE 10-16
MULTIPLICATION FACTOR TO ADJUST SLUDGE APPLICATION TO DEDICATED DISPOSAL SITE COSTS
IN FIGURE 10-13 FOR VARIATIONS IN DAYS OF APPLICATION PER YEAR
Assumptions: Design parameters are Listed in Table 10-4; number of days per year
that sludge is applied is variable.
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3-0
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2.0
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0.5
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50 100 150 200 250 300
NUMBER OF SLUDGE APPLICATION DAYS PER YEAR
350
-------
TABLE 10-4
ASSUMPTIONS USED IN DEVELOPING COST REQUIREMENT CURVES FOR LAND
APPLICATION OF SLUDGE TO DEDICATED DISPOSAL SITE
Parameter
Sludge Solids Concentration
Daily Application Period
Annual Application Period
Fraction of Land Required in Addition to
Appl ication Area
i
Fraction of Land Area Requiring Clearing
Fraction of Land Area Requiring Grading
Cost of Land
Cost of Grading Earthwork
Cost of Operation Labor :
Cost of Diesel Fuel
Cost of Monitoring Wells
Cost of Clearing
Assumed Value
5 percent
7 hr/day
200 days/yr
0.4
0
0
$3,120/acre
0
$13.50/hr
$1.35/gal
$5,200 each
0
201
-------
FIGURE 10-17
BASE CAPITAL COST OF A MUNICIPALLY OMNED SLUDGE LANDFILL AS A FUNCTION OF
ANNUAL SLUDGE VOLUME RECEIVED
Assumptions: Design parameters are Listed in Table 10-5.
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100
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1.0
0.1
10 20 30 ^0 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 10-18
BASE ANNUAL O&M COST FOR A MUNICIPALLY OWNED SLUDGE LANDFILL AS A FUNCTION
OF ANNUAL SLUDGE VOLUME RECEIVED
Assumptions: Design parameters are Listed in Table 10-5.
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10 20 30 40 50 60 70 80 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
-------
FIGURE 10-19
ANNUAL O&M REQUIREMENTS FOR A MUNICIPALLY OWNED SLUDGE LANDFILL AS A FUNCTION
OF ANNUAL SLUDGE VOLUME RECEIVED
Assumptions: Design parameters are listed in Table 10-5,
10 70 30
-------
FIGURE 10-19 (CONTINUED)
Assumptions: Design parameters are Listed in Table.10-5,
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-------
FIGURE 10-20
LAND AREA REQUIRED FOR A SLUDGE LANDFILL AS A FUNCTION OF ANNUAL
SLUDGE VOLUME RECEIVED
Assumptions: Design parameters are Listed in Table 10-5,
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10'
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10 20 30 ^O 50 60 70 80 90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
TABLE 10-5
ASSUMPTIONS USED IN DEVELOPING COST REQUIREMENT CURVES FOR LAND
APPLICATION OF SLUDGE TO SLUDGE LANDFILL
Parameter
Site Life
Trench Width
Trench Depth
Trench Spacing
Daily Application Period
Annual Application Period
Fraction of Site Used for Purposes Other Than
Trenching
Fraction of Site Requiring Clearing
i
Fraction of Site Requiring Initial Grading
Cost of Land
Cost of Grading Earthwork
Cost of Operation Labor
Cost of Diesel Fuel
Cost of Monitoring Wells
Cost of Clearing
Assumed Value
20 yr
10 ft
10 ft
15 ft
7 hr/day
240 days/yr
0.3
0.7
0.7
$3,120/acre
$2»600/acre
$13.50/hr
$1.35/gal
$5,200 each
$l,040/acre
207
-------
FIGURE 10-21
WEIGHT OF SLUDGE DRY SOLIDS CONTENT AS A FUNCTION OF WET SLUDGE VOLUME
AND SOLIDS CONCENTRATION
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300
250
200
150
100
50
10
20
30
50
60
70
80
90 100
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
-------
Step 2. Obtain the land area required for sludge application by dividing the
weight of dry solids to be applied annually by the appropriate dry
solids application rate, DSAR. Typical ranges for DSAR are given in
Table 10-6.
- TDSS
-
where :
SOAR = Sludge disposal area required, acres (acres /yr for land
reclamation).
TDSS = Annual dry solids applied to land, tons/yr.
DSAR = Dry sludge application rate, dry tons/acre/yr (dry tons/acre
for land reclamation).
(Note: For forest land application programs, multiply the quotient
in the above equation by the application frequency, e.g., if sludge
is to be applied every 5 years, multiply by 5.)
Step 3. Estimate the decimal fraction of land required in addition to sludge
application area (SOAR), e.g., buffer areas, unsuitable terrain,
access roads, etc., FWWAB. Typical values are:
• Cropland application = 0.4.
• Forest land application = 0.2.
t Reclamation application = 0.3.
t Dedicated disposal iSite = 0.4.
Step 4. Calculate the total land area required, TLAR, from the following:
TLAR = SOAR (1 + FWWAB)
!
Step 5. For dedicated disposal sites and sludge landfills, calculate the cost
of land assumed in the curve cost, CLC, from the following:
CLC = TLAR (3,120)
i
where
CLC = Curve land cost, $.
3,120 = Assumed land cost, $/acre.
i
Obviously, the CLC for the application of sludge to cropland, forest
land, and marginal land equals zero.
209
-------
TABLE 10-6
TYPICAL RANGES OF SLUDGE APPLICATION RATES (DSAR)
FOR VARIOUS LAND APPLICATION UNIT PROCESSES
Land Application Unit Process
Cropland Application
Reclamation of Marginal
Forest Land Application*
Dedicated Disposal Site
Typical Range of Sludge
Application Rates, DSAR
3-10 tons dry solids/acre/yr
10-100 tons dry sol ids/acre
20-40 tons dry solids/acre/
appl ication
30-100 tons dry solids/acre/yr
* Annual application.
t Usually one-time application (i.e., the sludge is applied only once to
a particular land area).
# Often multi-year application (e.g., every 5 years).
210
-------
Step 6. Calculate the actual cost of land, CLA, from the following:
CLA = TLAR (LANDCST)
where \
CLA = Actual cost of land, $.
LANDCST = Actual unit cost of land, $/acre.
Step 7. For cropland, forest land, dedicated disposal, and sludge 1 andf ill ,
adjust the curve capital cost to reflect actual land cost using the
foil owing:
ACC = CCC - CLC + CLA
where !
ACC = Adjusted curve capital cost, $.
CCC = Unadjusted curve capital cost, $.
It is assumed that cropland application, forest land application, dedi-
cated disposal site, and sludge landfill disposal programs use the same land
repeatedly. Therefore, the land purchase cost for these application programs
should be added to the capital cost. However, reclaimed disturbed or marginal
land usually receives sludge only once. Therefore, land costs for a marginal
land reclamation sludge application program should be added to the annual O&M
cost. :
10.8 Adjustment of Curve Costs to Include Clearing, Grading, and Lime Addition
In the base capital cost 'curves for the application of sludge to crop-
lands, forest lands, marginal lands, and dedicated disposal sites, the esti-
mated costs do not include the cost of clearing brush and trees, grading, and
lime addition for soil pH adjustment. The user can add these costs directly
to the costs obtained from each curve by using the following method after
adjusting for days per year of application, if required:
Step 1. Calculate the total land area required (TLAR) by following Steps 1
through 4 in Subsection 10.7.
Step 2. Estimate the decimal fraction of total land area requiring: clearing
of brush and trees, FWB; light grading, FRL6; medium grading, FRMS;
extensive grading, FREG; and lime addition for soil pH adjustment,
FRPH. :
211
-------
Step 3. Calculate the incremental costs for site clearing, grading, and pH
adjustment using the following equations:
Cost of Clearing = (Unit Cost of Clearing, $/acre) (FWB) (TLAR)
Cost of Grading = [(Unit Cost of Light Grading, $/acre) (FRLG) +
(Unit Cost of Medium Grading, $/acre) (FRMG) +•
(Unit Cost of Extensive Grading, $/acre) (FREG)]
(TLAR)
Cost of Liming = (Unit Cost of Lime Addition, $/acre) (FRPH) (TLAR)
Typical last quarter 1984 values for the above unit costs are given
in Table 10-7. Usually the landowner pays for these incremental land
preparation costs, except in the case of the dedicated disposal site
process.
Step 4. Add the sum of the applicable incremental costs calculated in Step 3
to the total O&M or capital cost for the process being evaluated,
obtained using the cost curves for that particular unit process.
As stated previously, it is assumed that cropland application, forest
land application, and dedicated disposal site programs use the same land
repeatedly. Therefore, the incremental land improvement costs for these
application programs should be added to the capital cost. However, reclaimed
disturbed or marginal land usually receives sludge only once. Therefore, land
improvement costs for a disturbed or marginal land reclamation program should
be added to the annual O&M cost.
212
-------
: TABLE 10-7
TYPICAL 1984 LAND PREPARATION COSTS FOR SLUDGE APPLICATION
Unit Cost
Description ($/acre)
Clearing of Brush and Trees 1,040
Light Grading i 520-1,040
Medium Grading , 1,250
Extensive Grading : 2,080
Lime Addition to Cropland 60
(2 tons 1ime/acre)
Lime Addition to Harginal Land 125
(4 tons 1 ime/acre)
213
-------
SECTION 11
SLUDGE STORAGE CURVES
11,1 Introduction
Provision for the storage of sludge is an important consideration for any
solids handling system. Storage is used for the following purposes:
* Ensures that solids handling systems are operating at full or optimum
capacity.
• Compensates for adjacent processes which are operated at different
rates or schedules.
• Provides buffer capacity necessary for shutdown due to routine mainte-
nance or repair.
This section presents capital and annual operation and maintenance curves
for three sludge storage methods: facultative lagoons, enclosed tanks, and
unconfined piles. Base capital cost curves for facultative lagoons and uncon-
fined pile storage include the cost of land. The base capital cost curve for
enclosed tank storage does not include land cost, because it is assumed that
the land area required for tank construction is small; tanks would thus likely
be constructed in conjunction with facilities on land which is already owned
by the utility. The procedure for adjusting the curve capital costs for
facultative lagoons and unconfined pile storage to account for an actual land
cost which is different from that assumed is presented in Subsection 11.5.
11.2 Facultative Lagoon Storage
Facultative lagoons have been used extensively in the past for liquid
sludge storage. The process, however, is usually limited to storage of sta-
bilized sludge to minimize odor problems.
Facultative sludge lagoons consist of an aerobic surface layer, usually
from 1 to 3 ft deep, a deeper anaerobic zone below, and a sludge storage zone
on the bottom. Both the aerobic and anaerobic zones are biologically active
with anaerobic stabilization providing substantial reduction of organic mate-
rial. Dissolved oxygen is supplied to the aerobic zone by (1) surface aera-
tors, (2) algae photosynthesis, and (3) surface transfer from the atmosphere.
Sludge accumulates in the lagoons and must be periodically removed.
Capital costs, O&M costs, and O&M requirements for facultative lagoon
storage are presented in Figures 11-1 through 11-3. The curves are based on
the algorithm in Appendix A-34 using the assumptions on the figures. The user
should consult Appendix A-34 to obtain more information on algorithm develop-
ment, design assumptions, and cost references.
214
-------
FIGURE 11-1
BASE
Assumpt ions:
CAPITAL COST OF FACULTATIVE LAGOON SLUDGE STORAGE AS A FUNCTION OF
LAGOON STORAGE CAPACITY
Sludge solids percent = 5 percent; volatile solids percent = 35 percent
of sludge solids; volatile solids destroyed by storage = 14 percent;
lagoon loading = 20 Ib volatile solids/1,000 sq ft/day; thickened
sludge solids content in lagoon = 6 percent; lagoon liquid depth = 12
ft; cost of land = $3,120/acre.
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LAGOON STORAGE CAPACITY (MILLION GALLONS)
50
-------
FIGURE 11-2
BASE ANNUAL O&M COST FOR FACULTATIVE LAGOON SLUDGE STORAGE AS A FUNCTION OF
LAGOON STORAGE CAPACITY
Assumptions: Design parameters are the same as for Figure 11-1; cost of Labor
$13.50/hr; cost of electricity = $0.094/kWhr.
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LAGOON STORAGE CAPACITY (MILLION GALLONS)
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FIGURE 11-3
ANNUAL O&M REQUIREMENTS FOR FACULTATIVE LAGOON STORAGE AS A FUNCTION OF
LAGOON STORAGE CAPACITY
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LAGOON STORAGE CAPACITY (MILLION GALLONS)
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LAGOON STORAGE CAPACITY (MILLION GALLONS)
Assumptions:
10 20 30 *0 SO 60 70 (0 90
ANNUAL SLUDGE VOLUME (MILLION GALLONS PER YEAR)
100
Design parameters are
the same as for Figure 11-1
NOTE : THE MATERIAL COST CURVE IS
FOR THE ANNUAL MAINTENANCE
MATERIALS AND SUPPLIES.
-------
11.3 Enclosed Tank Storage
Sludge may be stored in either aboveground or below-ground storage tanks.
Enclosed tanks require special equipment to handle the odorous and potentially
toxic and explosive gases that may be generated by storage. In addition,
tanks are usually mixed to maintain a homogeneous mixture of sludge in the
tank.
Base capital costs, O&M costs, and O&M requirements for both aboveground
and below-ground storage tanks are presented in Figures 11-4 through 11-6.
Curves are based on the algorithm in Appendix A-33, using the assumptions
noted on the curves. Base capital costs include purchase and installation of
tanks and appurtenant equipment. Aboveground tanks are constructed of rein-
forced concrete, whereas buried tanks are constructed of steel. Costs do not
include provisions for sludge transfer to and from storage tanks, or the cost
of land. Base annual O&M costs include labor, electrical energy, and replace-
ment parts and materials.
11.4 Unconfined Pile Storage
Dry sludge (over 40 percent solids) may be stored at treatment plants or
land application sites over relatively long periods in built-up "unconfined"
piles. Storage is in a well defined area consisting of a concrete slab and
drainage control structures. In areas of high rainfall, piles are covered to
prevent erosion. Usually, one or more skip loaders are required to build the
piles and to load sludge haul vehicles. Dewatered sludge which is relatively
high in moisture (15 to 40 percent solids) and volatile organics content is
not conducive to unconfined pile storage over long periods due to the develop-
ment of odors.
Figures 11-7 through 11-9 present base capital costs, base annual O&M
costs, and annual O&M requirements for unconfined pile storage. The curves
were obtained with the algorithm in Appendix A-34, using the design assump-
tions noted on the curves. Additional information may be obtained by refer-
ring to Appendix A-34.
11.5 Land Cost Adjustment
Due to the significant size of the land area which is utilized by facul-
tative lagoons and unconfined pile sludge storage, it is assumed that new land
will need to be acquired by the municipality for construction of these facili-
ties. Base capital costs presented in the curves for these unit processes
include the cost of land at an assumed unit cost of $3,120/acre. Because land
costs are highly variable, the user may desire to change this unit cost and,
hence, the process capital cost to more accurately fit local costs. This may
be accomplished using the procedures outlined below in Subsections 11.5.1 and
11.5.2 for facultative lagoons and unconfined pile storage, respectively.
11.5.1 Calculation of Total Land Area Required and Capital Cost Adjust-
ment for Facultative Lagoon Storage
218
-------
FIGURE 11-4
BASE CAPITAL COST OF ENCLOSED TANK SLUDGE STORAGE AS A FUNCTION OF
TANK STORAGE CAPACITY
Assumptions: Mixing energy = 0.3 hp/1,000 cu ft of tank volume; total dynamic head
25 ft; mixing pump efficiency = 0.7.
1 .0
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0.0 0.1 0.2 0.3 O.J» 0.5 0.6 0.7 0.8
STORAGE CAPACITY (MILLION GALLONS)
0.9 1.0
-------
FIGURE 11-5
BASE ANNUAL O&M COST OF ENCLOSED TANK SLUDGE STORAGE AS A FUNCTION OF
TANK STORAGE CAPACITY
Assumptions: Design parameters are the same as for Figure 11-4; cost of Labor
$13.50/hr; cost of electricity = $0.094/kWhr.
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•"f A n i ft
«C U . U 1 U
32 n ftftr
ui n » n n n i
/
x
X
•
/
X
i
/
^
t
,^
s*^
1
^1
jX^
t
N*a
^x-^
t
^^ix
(
^
^^
1
^^**
1
<
CD
).0 0.1 0.2 0.3 O.A 0.5 0.6 0.7 0.8
STORAGE CAPACITY (MILLION GALLONS)
0.9 1.0
-------
FIGURE 11-6
ANNUAL OSM REQUIREMENTS FOR ENCLOSED TANK SLUDGE STORAGE AS A FUNCTION
OF TANK STORAGE CAPACITY
PO
0 AHO_
0.0 O.I 0,1 O.J a,1! 0.5 t.t 0,7 0.8 0,S 1.0
STOHAGf CAPACITY (KILL ION GALLONS)
».0 O.I 0,2 0.3 0.* O.S 0.6 0.7 0,8 0.9 l.«
STORACE CAPACITr (MILLION GALLONS)
TAHK
0.0 0,1 0.2 0.) D.
-------
FIGURE 11-7
BASE CAPITAL COST OF UNCONFINED PILE OEWATEREO SLUDGE STORAGE AS A FUNCTION OF
FACILITY STORAGE CAPACITY
Assumptions:
10
ct
o
o
ro
ro
ro
10
o
o
O.
O
UJ
«/>
BQ
Storage pi L'e cross section area = 32 sq ft; storage period = 180 days;
cost of skip Loader(s) = $46,800 each; cost of concrete pad = $83,2007
acre; cost of drainage control = $20,800/acre; cost of Land = $3,1207
acre.
10
1 .0
0.1
25 50 75 100 125 150 175 200 225
STORAGE CAPACITY OF FACILITY (THOUSAND CUBIC YARDS)
250
-------
FIGURE 11-8
BASE ANNUAL OS« COST FOR UNCONFINEO PILE DEWATERED SLUDGE STORAGE AS A FUNCTION
OF FACILITY STORAGE CAPACITY
Assumptions: Design parameters are the same as for Figure 11-7; cost of Labor =
$13.50/hr; cost of diesel fuel = $1.35/gal.
ui
CL
VJ
o:
ro
GJ
in
o
o
_l
<
CO
1.0
0.1
0.01
25 50 75 100 125 150 175 200 225 250
STORAGE CAPACITY OF FACILITY (THOUSAND CUBIC YARDS)
-------
FIGURE 11-9
ro
ro
ANNUAL O&M REQUIREMENTS FOR UNCONFINED PILE DEWATERED SLUDGE STORAGE AS A FUNCTION
OF FACILITY STORAGE CAPACITY
10
0 25 50 75 100 125 ISO 175 200 225 250
STORAGE CAPACITY OF FACILITY (THOUSAND CUBIC YARDS)
10'
0 25 SO 75 100 125 150 17S 200 22S 2SO
STORAGE CAPACITY OF FACILITY (THOUSAND CUBIC YARDS)
0 '5 50 75 100 125 ISO 175 200 225 250
STORAGE CAPAC-ITY OF FACILITY (THOUSAND CUBIC YARDS)
Assumptions: Design parameters are
the same as for Figure 11-7.
NOTE : THE MATERIAL COST CURVE IS
FOR ANNUAL MAINTENANCE
MATERIALS AND SUPPLIES.
-------
Step 1. Calculate daily dry sludge solids input to the lagoon(s) from the
following equation:
t
DSS = (SV) (SSW)
where
DSS = Dry sludge solids input to lagoon, 1 b/day.
SS = Sludge solids concentration, percent.
SV = Daily sludge volume input to lagoon, gal /day.
SSW = Sludge specific weight, 1 b/gal , obtained from the
following table (interpolate where necessary):
Sludge Solids Concentration, Sludge Specific Weight,*
_ SS, Percent ; _ _ SSW. 1 b/gal _
2 8.38
5 8.45
10 8.57
20 8. 81
30 9.06
40 9.33
50 9.62
1
* Based on a sludge dry solids density of 85 Ib/ft^.
Step 2. Calculate daily volatile solids input to lagoon(s) from the following
equation:
VSS - -- (DSS)
where ',
VSS = Daily volatile solids input to lagoon(s), 1 b/day.
VSP - Volatile solids concentration, percent of dry solids weight.
Step 3. Calculate lagoon surface area required from the following:
(1,000)
LL
225
-------
where
TLSA = Total lagoon surface area required, ft .
o
LL = Lagoon loading, Ib volatile solids/1,000 ft of lagoon surface
area/day.
Step 4. Calculate total land area required from the following:
TIAR - (TLSA) (2.0)
1LftK 43,560
where
TLAR = Total land area required, acres.
2.0 = Factor to adjust for additional land area required for
buffer space, area between lagoons, storage area, etc.
o
43,560 = Conversion factor, ft /acre.
Step 5. Calculate the cost of land assumed in the curve cost, CLC, from the
foil owing:
CLC = TLAR (3,120)
where
CLC = Curve land cost, $.
3,120 = Assumed unit cost of land in curve, $/acre.
Step 6. Calculate the actual cost of land, CLA, from the following:
CLA = TLAR (LANDCST)
where
CLA = Actual cost of land, $.
LANDCST = Actual unit cost of land, $/acre.
Step 7. Adjust the curve capital cost to reflect actual land cost using the
following:
ACC = CCC - CLC + CLA
226
-------
where ;
ACC = Adjusted curve capital cost, $.
CCC = Unadjusted curve capital cost, $.
11.5.2 Calculation of Total Land Area Required and Capital Cost Adjust-
ment for Unconfined Pile Storage.
Step 1. Calculate volume of dewatered sludge to be stored from the following:
(sp)
-
where
SVCY = Sludge volume to be stored, yd .
SV = Daily sludge volume, gal /day.
SP = Storage period, :days.
202 = Conversion factor, gal /yd .
Step 2. Assuming an equilateral triangle cross section, calculate total land
area required from the following:
TLAR , (SVCY) (27) (2) (1.2)
(3)0'25 (X)0'5 (43,560)
where
TLAR = Total land area required, acres.
27 = Conversion factor, ft3/yd3.
1.2 = Factor to account for spacing between piles, area for
drainage control structures, etc.
X = Storage pile cross section area, ft^.
43,560 = Conversion factor, ft2/acre.
Step 3. Calculate the cost of land assumed in the curve cost, CLC, from the
foil owing:
CLC = TLAR (3,120)
where
CLC = Curve land cost, $.
3,120 = Assumed unit cost of land in curve, $/acre.
227
-------
Step 4. Calculate the actual cost of land, CLA, from the following:
CLA = TLAR (LANDCST)
where
CLA = Actual cost of land, $.
LANDCST = Actual unit cost of land, $/acre.
Step 5. Adjust the curve capital cost to reflect actual land cost using the
foil owing:
ACC = CCC - CLC + CLA
where
ACC = Adjusted curve capital cost, $.
CCC = Unadjusted curve capital cost, $.
228
-------
APPENDIX A
COST ALGORITHMS
Appendix Page
A-l Gravity Thickening 231
A-2 Flotation Thickening 238
A-3 Anaerobic Digestion. "... 244
A-4 Aerobic Digestion Using Mechanical Aerators 253
A-5 Aerobic Digestion Using Diffused Aeration. . . 259
A-6 Lime Stabilization 266
A-7 Thermal Treatment of Sludge 274
A-8 Centrifuge Dewatering 279
A-9 Belt Filter Oewatering 285
A-1Q Recessed Plate Filter Press Dewatering 291
A-ll Vacuum Filter Dewatering ....... ... 298
A-12 Sludge Drying Bed Dewatering 306
A-13 Chemical Conditioning with Lime 312
A-14 Chemical Conditioning with Ferric Chloride 319
A-15 Chemical Conditioning with Polymers. . 326
A-16 Fluldized Bed Incineration 332
A-17 Multiple Hearth Incineration 342
A-18 Composting - Windrow Method 350
A-19 Composting - Aerated Static Pil e Method 363
A-20 Liquid Sludge Truck Hauling, Including Sludge
Loading Facilities ;. 377
229
-------
APPENDIX A (continued)
Appendix Page
A-21 Dewatered Sludge Truck Hauling, Including Sludge
Loading Facilities . 385
A-22 Liquid Sludge Transport by Rail 394
A-23 Barge Transportation of Liquid Sludge for Ocean
Disposal . 403
A-24 Long-Distance Pipeline Transport of Liquid Sludge. ..... 411
A-25 Ocean Outfall Disposal 421
A-26 Land Application to Cropland 431
A-27 Land Application to Non-Food Chain Crops
(Other Than Forest Land) .... 443
A-28 Sludge Application to Marginal Land for Land
Reclamation 444
A-29 Land Application to Forest Land Sites 456
A-30 Land Application to Dedicated Disposal Site. . 468
A-31 Land Disposal to Sludge Landfill 481
A-32 Sludge Storage - Facultative Lagoons 495
A-33 Sludge Storage - Enclosed Tank 504
A-34 Unconfined Pile Storage of Dewatered Sludge 511
A-35 References 517
230
-------
APPENDIX A-l
GRAVITY THICKENING
A-l.l Background
Gravity thickening utilizes the difference in specific gravity between
the solids and water to achieve separation. Additional solids concentration
is achieved through compaction by the overlying solids.
Gravity thickening is commonly used to thicken primary sludge and com-
bined primary and waste biological sludge. Waste biological sludge alone gen-
erally does not thicken well in a gravity thickener. Chemical conditioning of
sludge prior to thickening is often done to improve thickener performance.
Chemical conditioning costs are covered in other sections of this handbook and
appendix.
Circular concrete tanks are the most common configuration for gravity
thickeners, although circular steel tanks and rectangular concrete tanks have
also been used. The following algorithm is based on the construction and
operation.of circular reinforced concrete tanks. The tank is equipped with a
slowly revolving sludge collector at the base of the tank. A truss-type
bridge is fastened between the tank walls and the center feed well. Overflow
passes over an effluent weir located around the circumference of the thick-
ener. Capital costs include construction of the unit, including earthwork
required, thickener mechanism and ancillary equipment, reinforced concrete,
and installation labor. Since gravity thickeners are not normally enclosed,
building space is not provided. Moreover, costs do not include equipment for
the control of odors. •
A-l. 1.1 Process Design
In general, gravity thickener design is based primarily on surface area
loading, hydraulic loading, and; total tank depth. These parameters are nor-
mally obtained through laboratory batch settling tests. Procedures for con-
ducting the tests and evaluating the design parameters are documented in the
literature. In the absence of these data, the table below (adapted from Ref-
erence 4) may be used as a guide in selecting a solids loading rate for vari-
ous sludges and unthickened sludge solids concentrations.
231
-------
(% Solids
Unthickened
2.5 to 5.5
0.5 to 1.2
1.5 to 4.0
by Weight)
Thickened
5 to 10
1 to 3
3 to 7
Surface Area Dry
Solids Loading Rate
(Ib/ft2/day)
20 to 30
6 to 10
8 to 16
Concentration
(% !
Type of SI udge
Primary Alone
Activated Sludge Alone
Combined Primary and
Activated Sludge
Hydraulic loading rates generally vary from 400 to 800 gpd/ft2 of surface
area. Detention time generally varies from 2 to 6 hours.
A-l.1.2 Algorithm Development
The following algorithm is based on the CAPDET program. Equations used
in the CAPDET algorithm for gravity thickening can be found on pages 2.61-18
through 2.61-31 of Reference 1. Cost outputs were based on these input para-
meters:
« Mass loading = 12 Ib/ft2/day.
t Underflow concentration = Influent concentration (percent) plus 2 per-
cent.
t Depth of tank = 9 ft.
* Cost of standard 90-ft-diameter thickener mechanism = $150,000.
Additional input parameters (projected 1983 values), as shown on Table
1-1, were obtained from construction cost guides (2, 3). Cost of the standard
thickener mechanism was obtained through equipment suppliers.
Capital costs obtained through the CAPDET program were fit to equations
using multiple regression curve fits. Costs were expressed as functions of
the thickener surface area. The O&M cost equations in this algorithm are
those presented in the CAPDET program. O&M requirements (labor and
electricity) are related to the solids processed per day.
A-1.2 Input Data
A-l.2.1 Daily sludge volume, SV, gal/day.
A-1.2.2 Sludge suspended solids concentration, SS, percent.
A-1.2.3 Sludge specific gravity, SSG, unitless.
A-1.2.4 Hours per day process is operated, HDP, hr/day.
A-1.2.5 Dry solids loading rate, SLR, Ib/ft2/day.
232
-------
A-1.3 Design Parameters
A-l.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user. No default value.
A-1.3. 2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-1.3. 3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is calcu-
lated with the following equation:
- SS (SS)
100 ~ (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Assumed sludge solids specific gravity, unitless.
A-1.3.4 Hours per day process is operated, HPD, hr/day. Default value =
24 hr/day. !
A-1.3.5 Dry solids loading rate, SLR, Ib/ft2/day. Default value =
1.8 SS + 6.
A-1.4 Process Design Calculations
A-l.4.1 Calculate dry solids handled per day.
= (SV) (SS) (SSG) (8.34)
jj00j (2,000)
where i
TDSS = Daily dry solids handled, tons/day.
8.34 = Density of water, Ib/gal.
2,000 = Conversion factor, Ib/ton.
A-1.4.2 Calculate thickener total surface area.
= (SV) (SS) (SSG) (62.43) (24)
(100) (SLR) (7.48) (HPD)
where
TSA = Total surface area,! ft2.
62.43 = Density of water, lb/ft3.
7.48 = Conversion factor, gal/ft3.
233
-------
A-1.5 Process Design Output Data
A-l.5.1 Daily dry solids handled, TOSS, tons/day.
o
A-1.5,2 Thickener total surface area, ISA, ft .
A-1.6 Quantities Calculations
A-l.6.1 Maintenance labor requirements.
A-1.6.1.1 If TDSS _<_ 2.7 tons/day, maintenance labor is calcu-
lated by:
ML = 141.4 (TDSS)0*566
A-1.6.1.2 If 2.7 < TDSS £ 13 tons/day, maintenance labor is
cal cul ated by:
ML = 164.8 (TDSS)0*4093
A-1.6.1.3 If TDSS > 13 tons/day, maintenance labor is cal cu-
1ated by:
ML - 91.04 (TDSS)0'6415
where
ML = Annual maintenance labor requirement, hr/yr.
A-1.6.2 Operation labor requirement.
A-1.6.2.1 If TDSS j£2.7 tons/day, operation labor is calculated
by:
OL = 152 (TDSS)0*7066
A-l.6.2.2 If 2.7 < TDSS <_ 13 tons/day, operation labor is cal-
cul ated by:
OL - 184.2 (TDSS)0*5046
234
-------
A-l.6.2.3 If TOSS > 13 tons/day, operation labor is calculated
by:
OL ='93.12 (TOSS)0'7704
where
OL = Annual operation labor requirement, hr/yr.
A-1.6.3 Electrical energy requirement.
A-1.6.3.1 If TDSS _<_ 50 tons/day, electrical energy is calcu-
lated by:
E = 4,500 (TDSS)0*301
A-1.6.3.2 If TDSS > 50 tons/day, electrical energy is calcu-
lated by:
E = 1,464 (TOSS)0*5881
where
E = Annual electrical energy requirement, kWhr/yr.
A-1.7 Quantities Calculations Output Data
A-l.7.1 Annual maintenance labor requirement, ML, hr/yr.
A-1.7.2 Annual operation labor requirement, OL, hr/yr.
A-1.7.3 Annual electrical energy requirement, E, kWhr/yr.
A-1.8 Unit Price Input Required
A-1.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-1.8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made, MSEC I. ;
A-1.8.3 Cost of operational and maintenance labor, COSTL, $/hr. Default
value = $13.00/hr (ENRCCI/4,006).
A-l.8.4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$13.00/hr (ENRCCI/4,006).
235
-------
A-1.9 Cost Cal cul ations
A-1.9.1 Annual. cost of operation and maintenance labor.
COSTLB = (ML + OL) (COSTL)
where
COSTLB - Total annual cost of operation and maintenance labor, $/yr.
A-1.9.3 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-1.9.3 Total base capital cost.
TBCC = [5.9 x 10"7 (TSA)3 - 0.013 (TSA)2 + 111.59 (TSA) + 41,164]
where
TBCC = Total base capital cost, $.
A-1.9.4 Annual cost of maintenance parts and materials. This cost is
expressed as 1 percent of the total base capital cost.
COSTPM = -jgg- (TBCC)
where
COSTPM = Annual cost of operation and maintenance parts and materials,
$/yr.
A-1,9.5 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTPM
where
COSTOM = Total annual operation and maintenance cost, $/yr,
236
-------
A-1.10 Cost Calculation Output Data
A-1.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-1.10.2 Annual cost of electrical energy, COSTEL, $/yr.
A-1.10.3 Annual cost of maintenance parts and materials, COSTPM, $/yr.
A-l.10.4 Total base capital cost of gravity thickening process, TBCC, $.
A-l.10.5 Total annual operation and maintenance cost for gravity thick-
ening process, COSTOM, $/yr.
237
-------
APPENDIX A-2
FLOTATION THICKENING
A-2.1 Background
In dissolved air flotation (DAF) thickening, air is introduced into a
solution that is being held at an elevated pressure, usually a separate super-
natant recycle stream. When this stream is combined with the incoming sludge
stream and released to atmospheric pressure, minute air bubbles are formed
which adhere to the suspended particles and become enmeshed in the solids
matrix. Since the density of the solids-air aggregate is less than that of
water, the agglomerate floats to the surface. The float is continuously
removed by a skimmer mechanism.
DAF thickening is used for biological sludges which have relatively low
solids concentrations, sludges with higher grease concentrations, and for
other sludges where DAF thickening usually provides better solids-liquid sep-
aration than a gravity thickener. Chemical conditioning of the sludge, often
involving polymer addition, is usually done prior to DAF thickening to enhance
performance. Chemical conditioning costs can be obtained using other sections
of this manual.
DAF thickeners can be rectangular or circular, constructed of concrete or
steel. This algorithm is based on the construction and operation of circular
reinforced concrete tanks. The capital cost includes flotation tank construc-
tion, and purchase and installation of the pressurizing pump, air injection
facilities, retention tank, back pressure regulating device, and skimmer mech-
anisms. Both surface and bottom sludge collectors are provided. Costs in-
clude a building of sufficient area to enclose the thickener and ancillary
equipment while providing adequate space for operation and maintenance. Costs
do not include mechanisms for the control of odors, often associated with
thickeners.
A-2.1.1 Process Design
DAF thickener design is based primarily on surface area loading and
hydraulic loading. In addition, parameters such as recycle ratio, air-to-
sol ids ratio, polymer type and dosage, and detention time are also important.
Bench-scale testing is often performed to evaluate the effects of design para-
meters on effluent sludge characteristics.
The table below provides typical surface area loading rates for selected
chemically conditioned sludges.
238
-------
Surface Area Dry Solids
Loading Rate. 1b/ft2/day
Type of Sludge
Primary Alone 20 to 30
Activated Sludge Alone 12 to 24
Combined Primary and 12 to 24
Activated Sludge
If the sludge is not chemically conditioned, the surface loading rates
shown in the table above should be reduced by approximately 50 to 60 percent.
Hydraulic loading rates generally vary from 1,200 to 4,000 gpd/ft*^ of surface
area.
A-2.1.2 Algorithm Development
The following algorithm is based on use of the-CAPDET program. CAPDET
algorithms are found in Reference 1, pages 2.61-5 through 2.61-17. Costs and
requirements were developed utilizing the program by varying sludge volume and
solids concentration entering the thickening unit, using the following input
parameters:
* Air pressure = 60 psig.
t Detention time in float tank = 0.5 hr.
• hydraulic loading = 3 gpm/ft^
• Recycle time in pressure tank - 2 min.
• Percent removal of solids = 80 percent.
• Air-to-sol ids ratio = 0.02.
* Float concentration (minimum) = 4 percent.
t Purchase cost of standard 350-ft^ air flotation unit = $94,000 (cost
includes basic mechanism to be mounted in the concrete tank, air pres-
surization tank, pressurization pump, pressure release valve, air
injection system, and electrical panel).
Additional input parameters (projected 1983 values) shown on Table 1-1
were obtained from construction cost guides (2, 3). Cost of the standard
thickener mechanism was obtained from equipment suppliers.
O&M requirement equations are those presented in the CAPDET program.
Capital costs obtained using the CAPDET program were fit to an equation using
a multiple regression program. Costs and requirements were expressed as func-
tions of the parameter most closely related to costs or requirements. O&M
requirements (labor and electricity) are related to the solids processed per
day, and capital cost is expressed as a function of the flotation tank surface
area.
239
-------
A-2.2 Input Data
A-2.2.1 Daily sludge volume, SV» gal/day.
A-2.2, 2 Sludge suspended solids concentration, SS, percent.
A-2.2. 3 Sludge specific gravity, SSG, unit! ess.
A-2.2. 4 ftours per day process is operated, HPD, hr/day.
A-2.2. 5 Solids loading, SLR, Ib/ft2/day.
A-2.3 Design Parameters
A-2.3.1 Daily sludge volume, SV, gal/day. This value must be input by
the user. No default value.
A-2.3. 2 Sludge suspended solids concentration, SS, percent. This value
must be input by the user. No default value.
A-2.3. 3 Sludge specific gravity, SSS, unitless. This value should be
provided by the user. If not available, default value is calcu-
lated with the following equation:
=
- SS
100 (1.42) (100)
where
SSG = Sludge specific gravity, unit!ess.
1.42 = Assumed sludge solids specific gravity.
A-2.3.4 Hours per day process is operated, HPD, hr/day. Default value =
24 hr/day.
A-2.3.5 Solids loading, SLR, Ib/ft2/day. Default value - 20 Ib/ft2/day.
A-2.4 Process Design Calculations
A-2.4.1 Calculate surface area.
= (SV) (SS) (SSG) (8.34) (24)
5-^- -553 ----- •
(SLR) (100) (HPD)
where
ISA = Surface area, ft2.
240
-------
A-2.4.2 Calculate dry solids produced.
- (SV) (SS) (SSG) (8.34)
(100) (2,000)
where
TDSS = Daily dry solids produced, tons/day.
A-2.5 Process Design Output Data
A-2.5.1 Surface area, ISA, ft2.
A-2.5.2 Daily dry solids produced, TDSS, tons/day.
A-2.6 Quantities Calculations
A-2.6.1 Annual operation 1abor requirement.
A-2.6.1.1 If TDSS _< 2.3 tons/day, operation labor is calculated
by:
OL = 560 (TDSS)0'4973
A-2.6.1.2 If TDSS > 2.3 tons/day, operation labor is calculated
by:
OL = 496 (TDSS)0*5092
where
OL = Annual operation labor requirement, hr/yr.
A-2.6.2 Annual maintenance 1abor requirement.
A-2.6.2.1 If TDSS _£ 3 tons/day, maintenance labor is calculated
by:
ML :- 156 (TDSS)0'4176
A-2.6.2.2 If TDSS > 3 tons/day, maintenance labor is calculated
by:
ML - 124 (TDSS)0*6429
241
-------
where
ML = Annual maintenance labor requirement, hr/yr.
A-2.6.3 Annual electrical energy requirement.
0 QA??
E = 63,000 (TDSS) *
where
E = Annual electrical energy requirement, kWhr/yr.
A-2.7 Quantities Calculations Output Data
A-2.7.1 Operation labor requirement, OL, hr/yr.
A-2.7.2 Maintenance labor requirement, ML, hr/yr.
A-2.7.3 Electrical energy requirement, E, kWhr/yr.
A-2.8 Unit Price Input Required
A-2.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-2.8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made, MSEC I.
A-2.8.3 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-2.8.4 Cost of electricity, COSTE, $/kWhr. Default value = $0.09/kWhr
(ENRCCI/4,006).
A-2.9 Cost Calculations
A-2.9.1 Annual cost of operation and maintenance labor.
COSTLB = (OL + ML) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-2.9.2 Annual cost of electrical energy.
COSTEL = (E.) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
242
-------
A-2.9.3 Total base capital cost.
A-2.9.3.1 If TSA <_ 40 ft2, base capital cost is calculated by:
TBCC = (108,600)
/ 40 ft2, base capital cost is calculated by:
TBCC • [-0.107 x 10"5 (TSA)3 + 0.0193 (TSA)2 + 454.5 (TSA) + 90,362]
t *J i
where
TBCC = Total base capital cost, $.
A-2.9.4 Annual cost of replacement parts and materials. This cost is
calculated as 1 percent of the base capital cost.
COSTPM - JL (TBCC)
where
COSTPM = Annual cost of replacement parts and materials, $/yr.
A-2.9.5 Annual cost of operation and maintenance.
i
COSTOM » COSTLB + COSTEL + COSTPM
where
COSTOM = Annual operation and maintenance cost, $/yr.
A-2.10 Cost Calculation Output Data
A-2.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-2.10.2 Annual cost of electrical energy, COSTEL, $/yr.
A-2.10.3 Annual cost of replacement parts and materials, COSTPM, $/yr.
A-2.10.4 Total base capital cost of flotation thickening process, TBCC, $.
A-2.10.5 Total annual operation and maintenance cost for flotation
thickening process, COSTOM, $/yr.
243
-------
APPENDIX A-3
ANAEROBIC DIGESTION
A-3.1 Background
During anaerobic digestion, sludges are stabilized through the biological
degradation of complex organic substances in the absence of free oxygen.
Typically, 25 to 45 percent of the raw sludge solids are destroyed during
anaerobic digestion through conversion to methane, carbon dioxide, water, and
soluble organic material. In addition, anaerobically digested sludges are
generally more easily dewatered than undigested sludges.
Most sludges produced from municipal treatment plants can be stabilized
through anaerobic digestion, provided that the sludge has a low concentration
of heavy metals and a volatile solids content above 50 percent. However,
since microorganisms are sensitive to fluctuating operating conditions, plants
that exhibit wide variations in sludge quantity and quality should carefully
consider the applicability of anaerobic digestion as a stabilization process.
Anaerobic digesters may be either cylindrical, rectangular, or egg-
shaped. The most common design (assumed in this algorithm) is a circular
digester with a diameter ranging from 20 to 125 ft, and a side water depth
between 20 and 40 ft. Tanks are usually constructed of reinforced concrete.
There are several common types of anaerobic digestion processes, includ-
ing single-stage low-rate digestion, high-rate digestion, two-stage high-rate
digestion, and others. Single-stage digesters are completely mixed and
heated. In two-stage digestion, only the first digester is mixed and heated;
the second stage provides gravity concentration of digested sludge solids, and
decanting of supernatant liquor. Selection and design of an anaerobic diges-
tion process requires experienced design engineers.
For this cost algorithm, it is assumed that single-stage low-rate diges-
tion is being used with heating and mixing of digester contents. Fuel energy
for heating is supplied by the methane generated during anaerobic digestion.
When digestion tank requirements exceed a diameter of 125 ft or side water
depths of 40 ft, two or more digesters are assumed.
Capital costs include excavation and construction of reinforced concrete
tanks, purchase and installation of floating cover(s), gas circulation equip-
ment, external heater(s) and heat exchanger(s), gas safety equipment, positive
displacement pumps, internal piping, and ancillary equipment. In addition,
capital costs include a two-story control building.
244
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A-3.1.1 Process Design
Traditionally, volume requirements have been determined from empirical
loading criteria, such as per capita volume allowance, as shown for 1 ow-rate
digestion in the table below (Reference 4).
Tank Vol ume
Sludge Type (ffycapita)
Primary sludge only 2 to 3
Primary sludge plus waste 4 to 6
activated sludge
Primary si udge pi us 4 to 5
trickling filter humus
Volatile solids loading rate has been suggested as a more direct method
of determining reactor volume. For low-rate digestion, volatile solids load-
ing rates range between 0.04 and 0.1 Ib volatile sol ids/day/ft .
Another important consideration in sizing an anaerobic digester is solids
retention time. The digester should be sized to allow adequate time for the
decomposition of volatile organics. Ten days has been suggested as the mini-
mum acceptable solids retention time for high-rate digesters operating near
95° F. Solids retention time for low-rate digestion ranges between 30 and 60
days.
A-3.1.2 Al gorithm Devel opment
The following algorithm is based on the CAPDET program. Equations used
in the CAPDET algorithm for anaerobic digestion can be found in Reference 1,
pages 2.19-45 through 2.19-78. Cost and requirement outputs were developed
utilizing the program by varying sludge volume and solids concentration enter-
ing the digester, using the following input parameters:
* Sludge specific gravity— 1.02.
t Percent volatile sol ids destroyed = 50 percent.
t Effluent concentration = percent influent + 2 percent.
• Digestion operating temperature = 95° F.
« Raw sludge temperature := 70° F.
« Volatile solids in raw sludge = 60 percent.
« Cost of standard 70-ft-diameter gas circulation unit = $51,000.
245
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t Cost of standard 1-million-Btu/hr heating unit = $64,000.
• Cost of standard 2-in-diameter gas safety equipment = $9,250 (includes
accumulator with drip trap, low-pressure check valve, pressure relief
and flame trap valve, flame trap, six drip traps, gas pressure gauge,
waste gas burner, and gas meter).
t Cost of standard size sludge pump = $4,000 (8 gal/min at 70 ft of
head).
Additional input parameters (projected 1983 values) shown on Table 1-1
were obtained from construction cost guides (2, 3). Costs of floating cover,
circulation unit, heating unit, safety equipment, and sludge pump were ob-
tained from equipment suppliers.
Equations for calculating OSM requirements such as labor and electrical
power were taken directly from the CAPDET program. For capital costs, values
obtained from the CAPDET program were fit to polynomial equations using multi-
ple regression curve fits. Costs and requirements are expressed as functions
of appropriate design and operating parameters. For example, capital cost is
expressed as a function of digester tank volume, and O&M requirements (labor
and electricity) are related to the solids processed per day. In calculating
operation and maintenance requirements, it was assumed that sufficient diges-
ter gas is produced to heat the digesters, and that no supplemental natural
gas is required.
A-3.2 Input Data
A-3.2.1 Daily sludge volume, SV, gal/day.
A-3.2.2 Sludge suspended solids concentration, SS, percent.
A-3.2.3 Percent volatile solids in raw sludge, PV, percent of total
solids dry weight.
A-3.2.4 Raw sludge specific gravity, SSG, unitless.
A-3.2.5 Digested sludge specific gravity, S6D, unitless.
A-3.2.6 Percent volatile solids converted to methane, carbon dioxide,
and water during digestion, PVR, percent.
A-3.2.7 Percent suspended solids in sludge effluent, SSE, percent.,
A-3.3 Design Parameters
A-3.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user. No default value.
A-3.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
246
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A-3.3.3 Raw sludge specific gravity, SSG, unit!ess. Default value =
1.02.
A-3.3.4 Digested sludge specific gravity, SGD, unitless. Default value
= 1.03.
A-3.3.5 Percent volatile solids in raw sludge, PV, percent. Default
value = 60 percent.
A-3.3.6 Percent volatile solids converted to methane, carbon dioxide,
and water during digestion, PVR, percent. Default value = 50
percent.
A-3.3.7 Percent suspended solids in digested sludge effluent, SSE, per-
cent. Default value = influent percent suspended solids + 2
percent.
A-3.4 Process Design Calculations
A-3.4.1 Calculate the volume of raw sludge to digester.
SV
where
VRS = Volume of raw sludge, ft3/day.
7.48 = Conversion factor, gal/ft3.
A-3.4.2 Calculate dry solids digested per day.
TDSS - (SV) (SS) (SSG) (8.34)
/in^ (2,000)
where
TDSS = Daily dry solids digested, tons/day.
8.34 = Density of water, .lb/gal.
2,000 = Conversion factor, lb/toru
A-3.4.3 Calculate solids retention time.
TD = (PVR - 30) (2)
where
i
TD = Solids retention time, days.
247
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A-3.4.4 Calculate digested sludge solids withdrawal.
SD = (TDSS) (2,000) [1 -
where
SD = Digested sludge solids withdrawal, Ib/day.
2,000 = Conversion factor, Ib/ton,
A-3.4.5 Calculate the volume of digested sludge.
VD -
(100)
, _
(SGD) (62.4) (SSE)
where
VD = Volume of digested sludge, ft3/day.
A-3.4.6 Calculate total digestion tank volume.
VT = [VRS - (|) (VRS - VD)] (TD)
where
o
VT = Total digestion tank volume, ft •
A-3.5 Process Design Output Data
A-3.5.1 Volume of raw sludge, VRS, ft3/day.
A-3.5. 2 Daily dry solids digested, TDSS, tons/day.
A-3.5. 3 Solids retention time, TD, days.
A-3.5. 4 Digested sludge solids withdrawal, SD, Ib/day.
A-3.5. 5 Volume of digested solids, VD, ft3/day.
A-3.5, 6 Total digestion tank volume, VT, ft3.
A-3.6 Quantities Calculations
A-3.6.1 Maintenance labor requirement.
A-3.6. 1.1 If TDSS £ 0.1 ton/day, maintenance labor is calcu-
lated by:
ML = 352
248
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A-3.6.1.2 If 0.1 £ TOSS <_ 1 ton/day, maintenance labor is cal
cul ated by:
ML = 448 (TDSS)0*105
A-3.6.1.3 If 1 < TDSS £ 10 tons/day, maintenance labor is cal
cul ated by:
ML = 448 (TOSS)0'470
A-3.6.1.4 If TDSS > 10 tons/day, maintenance labor is calcu-
lated by:
ML = 200 (TDSS)0*804
where
ML = Annual maintenance labor requirement, hr/yr.
A-3.6.2 Operation labor requirement.
A-3.6.2.1 If TDSS _<_0.1 ton/day, operation labor is calculated
by:
OL = 608
A-3.6.2.2 If 0.1 < TDSS _< 1 ton/day, operation labor is cal cu-
1ated by:
OL = 720 (TDSS)0*0734
A-3.6.2.3 If 1 < TDSS _<_10 tons/day, operation labor is calcu-
lated by:
OL = 720 (TDSS)0*4437
A-3.6.2.4 If TDSS > 10 tons/day, operation labor is calculated
by: ;
OL = 280 (TDSS)0*8405
249
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where
OL = Operation labor requirement, hr/yr.
A-3.6.3 Electrical energy requirement.
A-3.6.3.1 If TOSS _< 8.5 tons/day, electrical energy is calcu-
lated by:
E = 46,720 (TOSS)0*596
A-3.6.3.2 If TOSS > 8.5 tons/day, electrical energy is calcu-
lated by:
E = 30,691 (TDSS)0'800
where
E = Annual electrical energy requirement, kWhr/yr.
A-3.7 Quantities Calculations Output Data
A-3.7.1 Annual maintenance labor requirement, ML, hr/yr.
A-3.7.2 Annual operation labor requirement, OL, hr/yr.
A-3.7.3 Annual electrical energy requirement, E, kWhr/yr.
A-3.8 Unit Price Input Required
A-3.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-3.'8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made, MSEC I.
A-3.8.3 Cost of operation and maintenance labor, COSTL, $/hr. Default
value = $13.0Q/hr (ENRCCI/4,006).
A-3.8.4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-3.9 Cost Calculations
A-3.9.1 Annual cost of operation and maintenance labor.
COSTLB - {ML + OL) {COSTL)
250
-------
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A~3.9.2 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL - Annual cost of electrical energy, $/yr.
A-3.9.3 Annual maintenance material and supply cost.
A-3.9.3.1 If VT _< 10,300 ft3, annual material and supply cost is
cal cul ated by:
COSTMS - (3,677)
A-3.9.3.2 If 10,300 < VT <_ 20,000 ft3, annual material and supply
cost is calculated by:
COSTMS = [(0.17) (VT - 10,300) + 3,677]
A-3.9.3.3 If 20,000 < VT <_ 100,000 ft3, annual material and sup-
ply cost is calculated by:
COSTMS = [4.1 x 10"11 (VT)3 - 6.4 x 10"6 (VT)2
-i- 0.2970 (VT) -i- 1,641] ^jjf-
A-3.9.3.4 If VT > 100,000 ft3, annual material and supply cost is
cal cul ated by:
COSTMS = [4.3 x 10"14 (VT)3 - 7.4 x ID"8 (VT)2
+ 0.046 (VT) + 4,038] ^l|p-
where
COSTMS = Annual maintenance material and supply cost, $/yr.
251
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A-3.9.4 Total base capital cost.
A-3.9.4.1 If VT <_ 10,300 ft3, total base capital cost is calcu-
lated by:
TBCC * (395,000)
A-3.9.4.2 If 10,300 < VT £ 80,000 ft3, total base capital cost is
cal oil ated by:
TBCC = [2.2 (VT) + 372,440]
A-3.9.4.3 If VT > 80,000 ft3, total base capital cost is calcu-
lated by:
TBCC = [5.9 x 10"12 (VT)3 - 1.14 x 10"5 (VT)2
+ 7.5 (VT) + 36,700]
where
TBCC = Total base capital cost, $.
A-3.9.5 Annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTMS
where
COSTOM = Annual operation and maintenance cost, $/yr
A-3.10 Cost Calculation Output Data
A-3.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-3.10.2 Annual cost of electrical energy, COSTEL, $/yr.
A-3.10.3 Annual maintenance material and supply cost, COSTMS, $/yr.
A-3.10.4 Total base capital cost of anaerobic digestion process, TBCC, $.
A-3.10.5 Annual operating and maintenance cost for anaerobic digestion
process, COSTOM, $/yr.
252
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APPENDIX A-4
AEROBIC DIGESTION USING MECHANICAL AERATORS
A-4,1 Background ',
Aerobic digestion Is the stabilization of raw sludge under aerobic condi-
tions, similar in principle to the activated sludge process. Sludge solids
are converted to carbon dioxide, water, and ammonia through the microbial
degradation of the sludge solids. Traditionally, aerobic digestion has been
used at small treatment plants (less than 5 mgd), although the process has
also been used at larger plants.
The advantages of aerobic digestion over anaerobic digestion include:
* Lower capital cost than anaerobic digestion.
o Easier to operate than anaerobic digestion.
« Virtually odor free ope'ration.
o Produces a supernatant return flow which is low in BOD, SS, and ammo-
nia nitrogen.
Disadvantages of aerobic digestion are:
* High energy consumption.
o The digested sludge has poor mechanical dewatering characteristics.
e The process is significantly affected by cold temperature, which
reduces biological activity and may cause mechanical problems with
surface aerators during freezing conditions.
o Methane, often used as a fuel source in anaerobic digestion, is not
produced.
Aerobic digesters are usually rectangular open tanks constructed of con-
crete or steel. In cold weather areas, the tanks are often placed below
ground to minimize heat losses. The air (oxygen) necessary for oxidation can
be added to the sludge mass by mechanical surface aerators, as covered in this
cost algorithm, or by air diffusors, as covered in Appendix A-5.
The following algorithm is based on the construction of rectangular rein-
forced concrete digesters. Capital costs include: excavation, construction
of reinforced concrete tanks, purchase of mechanical aerators and ancillary
equipment, and installation of all equipment.
253
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A-4.1.1 Process Design
The selection and design of aerobic digestion units is complex. Minimum
temperature, volatile solids reduction, sludge characteristics, detention
time, sludge age, and other factors are involved. Typical design parameters
(References 1, 4) are presented in the table below.
Design Parameter Typical Value
Hydraulic detention time, days at 68° F:
Activated sludge only 12 to 16
Activated sludge from plant operated 16 to 18
without primary settling
Primary plus activated or trickling 18 to 22
filter sludge
Solids loading, Ib volatile solids/ft3/day 0.1 to 0.2
Oxygen requirement, Ib 02/lb of volatile 2
solids destroyed
Tank volume in ft3/capita 3 to 4
Air requirement, 20 to 60 ft3/min/1,000 ft3 20 to 60
o
Energy requirements for mixing, hp/1,000 ft0 0.5 to 1.0
A-4.1.2 Algorithm Development
The following algorithm is based on use of the CAPDET program. The
CAPDET algorithm for aerobic digestion with mechanical aeration is found in
Reference 1, pages 2.19-23 through 2.19-44. Costs and requirements were
developed utilizing the program by varying sludge volume and solids concentra-
tion entering the aerobic digester, using the following input parameters:
t Detention time = 20 days.
• Volatile solids destroyed = 45 percent.
• Sludge specific gravity = 1.02.
• Mixed liquor solids = 12,000 mg/1.
• Solids in digested sludge = 4 percent.
• Ratio of oxygen saturation in waste to oxygen saturation in water =
0.9.
• Standard transfer efficiency = 1.68 Ib 02/hp-hr.
254
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t Temperature in digester = 73 °F.
• Cost of standard slow speed, pier-mounted 20-hp aerator = $21,200.
Additional input parameters (projected 1983 values) shown on Table 1-1
were obtained from construction cost guides (2, 3). Cost of the standard
aerator was obtained from equipment suppliers.
Capital costs, O&M costs, ,and O&M requirements, except for electrical
energy, were obtained through use of the CAPDET program, and were fit to a
polynomial equation using a multiple regression program. Electrical energy
was calculated directly from the horsepower required for aeration. Costs and
requirements were expressed as functions of the total aeration horsepower
requi red.
A-4.2 Input Data
A-4.2.1 Daily sludge volume, SV, gal/day.
A-4.2.2 Sludge suspended solids concentration, SS, percent.
A-4.2.3 Sludge specific gravity, SSG, unitless.
A-4.2.4 Percent volatile solids in raw sludge, PV, percent.
A-4.2.5 Percent volatile solids converted to carbon dioxide and water
during digestion, PVR, percent.
A-4.3 Design Parameters
A-4.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user. No default value.
A-4.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-4.3.3 Sludge specific gravity, SSG, unitless. Default value = 1.02.
A-4.3.4 Percent volatile solids in raw sludge, PV, percent. Default
value = 60 percent.
A-4.3.5 Percent volatile solids converted to carbon dioxide and water
during digestion, PVR, percent.. Default value = 45 percent.
i
A-4.4 Process Design Calculations
A-4.4.1 Calculate dry solids digested per day.
- ($V) (SSG) (SS) (8.34)
(100)
255
-------
where
DSS = Daily dry solids digested, 1 b/day.
A-4.4.2 Calculate daily oxygen requirement.
nR _ (2) (DSS) (PV) (PVR)
UR (100) (100)
where
OR = Oxygen requirement, 1 b/day.
2 = Oxygen required for oxidation of volatile solids, lb 02/1 b volatile
sol ids converted.
A-4.4»3 Calculate total horsepower required for aeration.
THP =
,nr
, .
(1.68) (24)
where
THP = Total horsepower required, hp.
1.68 = Oxygen transfer rate, Ib Q2/hp-hr.
A-4.5 Process Design Output Data
A-4. 5.1 Daily dry solids digested, DSS, 1 b/day.
A-4.5. 2 Daily oxygen requirement, OR, 1 b/day.
A-4. 5. 3 Total horsepower required, THP, hp.
A-4. 6 Quantities Cal cul ati ons
A-4. 6.1 Calculate operation and maintenance labor requirement.
L * 2.3 x 10"7 (THP)3 - 3.4 x 1Q~3 (THP)2 + 8.47 (THP) + 1,013
where
L = Annual operation and maintenance labor requirement, hr/yr.
A-4. 6.2 Calculate electrical energy requirement.
E - (THP) (24) (365) (0.746)
256
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where
E = Annual electrical energy requirement, kWhr/yr.
0.746 - Conversion factor, hp to kW.
A ^4.7 Quantities Calculations Output Data
A-4.7.1 Annual operation and maintenance labor requirement, L, hr/yr,
A-4.7.2 Annual electrical energy requirement, E, kWhr/yr.
A-4.8 Unit Price Input Required
A-4.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-4.8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made, MSEC I.
A-4.8.3 Cost of operation and maintenance labor, COSTL, $/hr. Default
value = $13.00/hr (ENRCCI/4,006).
I
A-4.8.4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0..09/kWhr (ENRCCI/4,006).
A-4.9 Cost Calculations
A-4.9.1 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB - Annual cost of operation and maintenance labor, $/yr.
A-4.9.2 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-4.9.3 Annual maintenance material and supply cost.
COSTMS = [1.01 x 10"6 (THP)3 - 0.00163 (THP)2
-i- 7.257 (THP) + 1,175]
257
-------
where
COSTMS = Annual maintenance material and supply cost, $/yr.
A-4.9.4 Total base capital cost.
TBCC = [-0.00169 (THP)3 + 2.07 (THP)2
-f- 1,564 (THP) + 152,850] ENRCCI
4,006
where
TBCC * Total base capital cost, $.
A-4.9.5 Annual operation and maintenance cost.
COSTOM - COSTLB + COSTEL + COSTMS
where
COSTOM = Annual operation and maintenance cost, $/yr.
A-4.10 Cost Calculation Output Data
A-4.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-4.10,2 Annual cost of electrical energy, COSTE, $/yr.
A-4.10.3 Annual maintenance and material supply cost, COSTMS, $/yr.
A-4.10.4 Total base capital cost of mechanical aerobic digestion pro-
cess, TBCC, $.
A-4.10.5 Annual operating and maintenance cost for mechanical aerobic
digestion process, COSTOM, $/yr.
258
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APPENDIX A-5
AEROBIC DIGESTION USING DIFFUSED AERATION
A-5.1 Background
Reference is made to Appendix A-4, which briefly discusses aerobic diges-
tion in general. Aerobic digestion using diffused aeration is similar to
aerobic digestion using mechanical aerators, except for the method of intro-
ducing and mixing air (oxygen) with the digester contents. If activated
sludge treatment is used at the treatment plant and aerobic digestion is con-
sidered, it is advantageous to use diffused aeration, since a common blower
facility can supply air to both the digester and the activated sludge reac-
tors. Swing arm diffusers are commonly used in both the activated sludge
reactor and the aerobic digester.
The following algorithm is based on the construction of rectangular rein-
forced concrete digesters. Capital costs include: excavation, construction
of reinforced concrete tanks, and purchase and installation of swing arm
headers, diffusers, and ancillary equipment. The depth and width of the aera-
tion tanks are fixed at 15 ft and 30 ft, respectively. Capital costs do not
include the cost of blowers, associated equipment, and blower building.
A-5.1.1 Process Design
The user is referred to Appendix A-4 for major design considerations of
aerobic digestion. The following table (References 1, 4) presents typical
design parameters for aerobic digestion using diffused aeration.
Design Parameter Typical Value
Hydraulic detention time,,days at 68 °F:
Activated sludge only 12 to 16
Activated sludge from plant operated 16 to 18
without primary settling
Primary plus activated or trickling 18 to 22
f 11 ter si udge
Solids loading, Ib volatile solids/ft3/day 0.1 to 0.20
Oxygen requirement, Ib 02/1 b of volatile 2
solids destroyed
259
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Tank volume in ft3/capita 3 to 4
Air requirement, ft 3/min/1,000 ft3 20 to 60
*2
Energy requirement for mixing, cfm/1,000 ft 20 to 30
A-5,1.2 Algorithm Development
The following algorithm is based on use of the CAPDET program., The
CAPDET algorithm for aerobic digestion with diffused aeration is found in Ref-
erence 1, pages 2.19-4 through 2.19-22. Costs and O&M requirements were
developed utilizing the program by varying sludge volume and solids concentra-
tion entering the aerobic digester, using the following input parameters:
• Detention time = 20 days.
• Influent volatile solids = 60 percent.
t Volatile solids destroyed = 45 percent.
» Sludge specific gravity = 1.02.
* Mixed liquor solids = 12,000 mg/1.
• Ratio of oxygen saturation in waste to oxygen saturation in water =
0.9.
t Standard transfer efficiency = 8 percent.
t Temperature in digester = 73 °F.
t Cost of standard 12.0-scfm coarse-bubble diffuser = $14.00.
t Cost of standard 550-scfm swing arm diffuser = $6,500.
Additional input parameters (projected 1983 values) shown on Table 1-1
were obtained from construction cost guides (2, 3). Costs of the standard
diffusers and headers were obtained from equipment suppliers.
Equations for O&M requirements are those used in the CAPDET program, with
the exception of electrial power, which is based on oxygen demand and energy
requirements for oxygen transfer. Capital costs obtained from the CAPDET pro-
gram were fit to polynomial equations using multiple regression curve fits.
Costs and O&M requirements were expressed as functions of the parameter
most closely related to costs or requirements. For example, O&M requirements
(labor and electrical energy) are related to the air supply required; capital
cost is expressed as a function of the sludge volume.
A-5.2 Input Data
A-5.2.1 Daily sludge volume, SV, gal/day.
260
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A-5.2.2 Sludge suspended solids concentration, SS, percent.
A-5.2.3 Sludge specific gravity, SSG, unitless.
A-5.2.4 Percent volatile solids in raw sludge, PV, percent.
A-5.2.5 Percent volatile solids converted to carbon dioxide and water
during digest!ons PVR, percent.
A-5.2,6 Hydraulic detention time, TD, days.
A-5.2.7 Efficiency of oxygen transfer from air to water, STE, percent.
A-5.2.8 Transfer rate of oxygen to water per hp-hr, TR, Ib 02/hp-hr.
A-5.3 Design Parameters
A-5.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user. No default value.
A-5.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-5.3.3 Sludge specific gravity, SSS, unitless. Default value = 1.02.
A-5.3.4 Percent volatile solids in raw sludge, PV, percent. Default
value = 60 percent.
A-5.3.5 Percent volatile solids converted to carbon dioxide and water
during digestion, PVR, percent. Default value = 45 percent.
A-5.3.6 Hydraulic detention time, TD, days. Default value = 20 days.
A-5.3.7 Efficiency of oxygen transfer from air to water, STE, percent.
Default value = 8 percent.
A-5.3.8 Transfer rate of oxygen to water per hp-hr, TR, Ib Og/hp-hr.
Default value = 1.0 Ib/hp-hr.
A-5.4 Process Design Calculations
A-5.4.1 Calculate dry solids digested per day.
-JSV) (SS) (SSG) (8.34)
-r (100)
where
DSS = Daily dry solids digested, Ib/day.
8.34 = Density of water, Ib/gal.
261
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A-5.4.2 Calculate daily oxygen requirement.
OR - (2) (PSS) (PV) (PVR)
UK (100) (100)
where
OR = Oxygen requirement, 1 b/day.
2 = Oxygen required for oxidation of volatile solids, 1 b Q£/I b volatile
sol ids converted.
A-5.4.3 Calculate air required to satisfy oxygen demand.
TAIR - (OR) (100)
iK (STE) (0.56) (0.0176) (24) (60)
where
TAIR = Total air required, scfm.
0.56 = Factor for conversion from standard transfer efficiency (oxygen
to water) to transfer efficiency of oxygen to mixed liquor at
73 °F, decimal percent.
0.0176 = Conversion factor, Ib 02/ft3 air.
A-5.5 Process Design Output Data
A-5.5.1 Daily dry solids digested, DSS, 1 b/day.
A-5.5.2 Daily oxygen requirement, OR, 1 b/day.
A-5.5.3 Daily air requirement, TAIR, scfm.
A-5.6 Quantities Cal cul ations
A-5.6.1 Calculate operation labor requirement.
A-5.6.1.1 If TAIR <_ 3,000 scfm, operation labor is calculated
by:
OL = 62.36 (TAIR)0'3972
A-5.6.1.2 If TAIR > 3,000 scfm, operation labor is calculated
by:
OL = 26.56 (TAIR)0*5038
262
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where
OL = Operation labor requirement, hr/yr.
A-5.6.2 Calculate maintenance labor requirement.
A-5.6.2.1 If TAIR _<_ 3,000 scfm, maintenance labor is calculated
by:
ML = 22.82 (TAIR)0*4379
A-5.6.2.2 If TAIR > 3,000 scfm, maintenance labor is calculated
by:
ML * 6.05 (TAIR)0'6037
where
ML = Maintenance labor requirement, hr/yr.
A-5.6.3 Calculate annual electrical energy requirement.
[365)
_ (OR) (36
" (Tbj (1.
where
E = Annual electrical energy requirement, kWhr/yr.
1.34 = Conversion factor, hp-hr to kWhr.
A-5.6.4 Calculate maintenance material and supply cost factor. This
item includes repair and replacement costs. It is calculated as
a percentage of the total base capital cost.
OMMP = 38 (sv)~°*2602
where
OMMP = Annual maintenance material and supply cost factor, percent.
A-5.7 Quantities Calculations Output Data
A-5.7.1 Annual operation 1 abor requirement, OL, hr/yr.
A-5.7.2 Annual maintenance labor requirement, ML, hr/yr.
A-5.7.3 Annual electrical energy requirement, E, kWhr/yr.
263
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A-5.7.4 Annual maintenance material and supply cost factor, OMMP,
percent.
A-5.8 Unit Price Input Required
A-5.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-5.8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made, MSEC I.
A-5.8.3 Cost of operation and maintenance labor, COSTL, $/hr. Default
value = $13.00/hr (ENRCCI/4,006).
A-5.8.4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-5.9 Cost Calculations
A-5.9.1 Annual cost of operation and maintenance labor.
COSTLB - (OL + ML) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-5.9.2 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-5.9.3 Total base capital cost.
A-5.9.3.1 If sludge suspended solids, SS, is 1 percent, total
base capital cost is calculated by:
TBCC = [-1.987 x 10"11 (SV)3 + 1.7 x 10"5 (SV)2
+ 5.737 (SV) + 259,240]
264
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A-5. 9. 3.2 If sludge suspended solids, SS, is 2 percent, total
base capital cost is calculated by:
TBCC = [-1.603 x 10"11 (SV)3 + 1.57 x 10~5 (SV)2
+ 6.178 (SV) + 271,910]
A-5.9. 3. 3 If sludge suspended solids, SS, is 3 percent, total
base capital cost is calculated by:
TBCC = [-1.498 x iO"11 (SV)3 + 1.68 x 10"5 (SV)2
+ 6.446 (SV) + 300,150]
where
TBCC = Total base capital cost, $.
A-5. 9. 4 Annual maintenance material and supply cost.
(TBCC)
where
COSTMS = Annual maintenance material and supply cost.
A-5. 9. 5 Annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTMS
where
COSTOM = Annual operation and maintenance cost, $/yr
A-5. 10 Cost Calculation Output Data
A-5. 10. 1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-5. 10. 2 Annual cost of electrical energy, COSTE, $/yr.
A-5. 10. 3 Annual maintenance material supply cost, $/yr.
A-5. 10. 4 Total base capital cost of diffused aerobic digestion process,
TBCC, $.
A-5. 10. 5 Annual operation and maintenance cost for diffused aerobic
digestion process, COSTOM, $/yr.
265
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APPENDIX A-6
LIME STABILIZATION
A-6.1 Background
Lime stabilization is a process in which lime is added to raw sludge in a
quantity sufficient to raise the pH of the sludge to approximately 12.0 for at
least 2 hours. The lime-stabilized sludge readily dewaters with mechanical
equipment (e.g., filter press, centrifuge, etc.), and is generally suitable
for disposal to landfill, dedicated disposal site, or application to agricul-
tural land (except where the existing agricultural soil already has a high
pH).
A potential disadvantage of the lime stabilization method is that the
mass of dry sludge solids is increased by the lime added and the chemical pre-
cipitates that result from the addition. Because of the increased sludge vol-
ume, the cost of transport and disposal/appl ication is often greater for lime-
stabilized sludge than for sludge stabilized by other methods (e.g., anaerobic
digestion).
Two forms of lime are commercially available: (1) quicklime (CaO) and
(2) hydrated lime (Ca(OH)2). Quicklime is less expensive but must be con-
verted to hydrated lime on site by slaking. Hydrated lime can be mixed with
water and applied directly. Generally, larger treatment plants purchase
quicklime, and smaller sewage treatment plants use hydrated lime. For a spe-
cific plant, a detailed economic analysis is necessary which takes into
account plant size, chemical requirements, chemical costs, and labor and main-
tenance requirements. In this cost algorithm, the use of hydrated lime is
assumed in developing the cost default values. This assumption should produce
adequate cost estimates for small and medium size plants (those using up to 5
tons of lime/day), but may result in overestimating O&M costs for larger
pi ants.
A-6.1.1 Process Design
The design of a lime stabilization system consists of two parts: (1)
design of a lime handling system; and (2) design of the sludge mixing system.
The design of each is briefly described below.
Design of the lime handling system depends on the form and quantities of
lime received at the treatment plant. Lime can be stored in steel or concrete
silos or bins. At a minimum, sufficient storage capacity to provide a 7-day
supply of lime should be provided; however, a 2- or 3-week supply is desir-
able. In addition, the total storage volume should be at least 50 percent
greater than the capacity of the delivery rail car or truck to ensure adequate
lime supply between shipments.
266
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Dry hydrated lime is delivered from storage to a dilution tank fitted
directly onto the feeder. The dilution tank is agitated by either compressed
air, water jets, or impel 1 er-type mixers. From the dilution tank, the slurry
is then transferred to the sludge mixing tank. Smaller treatment plants pur-
chase and store bagged hydrated lime which is mixed with water and metered to
the sludge mixing tank as required.
The mixing tank is sized based on detention time. Optimally, the mixing
tank should be sized to hold the lime/sludge mixture for 30 minutes. This
detention time should allow sufficient contact to raise the pH beyond 12.5.
Mixing tanks can be operated in batch or continuous mode. Tank mixing is
accomplished either with diffused air or mechanical mixers. Diffused air is
more commonly used in lime stabilization.
The lime stabilization process in this cost algorithm includes a lime
storage silo sized for 30 days storage; dual batch mixing tanks, each having a
capacity to hold 0.5 hours of plant design sludge flow; and a lime feeding
system. Normal costs for piping, pumps, electrical, and other accessories are
included. !
A-6.1.2 Al gorithm Devel opment
The following algorithm follows the basic sequence used by an engineer
when designing a lime stabilization process. Dosage, contact time, labor,
electrical requirements, and capital costs were obtained from information in
Reference 4, pages 6-104 through 6-107. Lime costs are based on vendor
quotes.
A-6.2 Input Data
A-6.2.1 Daily sludge volume, SV, gal/day.
A-6.2.2 Sludge suspended solids concentration, SS, percent.
A-6.3 Design Parameters
A-6.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-6.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-6.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is calcu-
lated using the following equation:
where
SSG --
1.42 =
SSG =
100 - SS
TTJO
Tssy
(1.42) (100)
Sludge specific gravity, unitless.
Assumed sludge solids specific gravity,
267
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A-6.3.4 Daily operation period, HPD, hr/day. Default value = 8 hr/day.
A-6.3.5 Annual operation period, DRY, days/yr. Default value = 365
days/yr.
A-6.3.6 Sludge detention time in mixing tank, DT, hr/batch. Default
value = 0.5 hr.
A-6.3.7 Lime dosage as a fraction of dry sludge solids mass, LD, 1 b of
Ca(OH)2/lb of dry sludge solids. Default value = 0.3. The lime
dosage required is determined by the type of sludge, its chemi-
cal composition, and the solids concentration. The following
tables are given to provide guidance in selecting an appropriate
value.
APPROXIMATE LIME DOSE REQUIRED TO RAISE TO 12.5 THE pH OF
A MIXTURE OF PRIMARY SLUDGE AND TRICKLING FILTER HUMUS
AT DIFFERENT SOLIDS CONCENTRATIONS
Solids Concentration (SS) (%)
1
2
3
4
Lime Dose (LD)
(1 b Ca(OH)2/1b dry solids)
0.39
0.32
0.27
0.23
LIME DOSE REQUIRED TO KEEP pH ABOVE 11.0 FOR AT LEAST 14 DAYS
Type of SI udge
Primary Sludge
Activated Sludge
Septage
Alum-sludge*
Alum sludge* Plus
Primary Sludget
Iron-sludge*
Lime Dose (LD)
(Ib Ca(OH2)/lb
suspended sol ids)
0.10 - 0.15
0.30 - 0.50
0.10 - 0.30
0.40 - 0.60
0.25 - 0.40
0.35 - 0.60
* Precipitation of primary treated effluent.
t Equal proportions by weight of each type of sludge.
A-6.3.8 Hydrated lime content of the lime product used, LC, percent.
Default value = 90 percent.
268
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A-6.4 Process Design Calculations
A-6.4.1 Calculate annual lime requirement.
•in _ (8.34) (SV) (SS) (SSG) (LD) (365) (100)
HLK _ (100) (LC)
where
ALR = Weight of lime product required annually, 1 b/yr.
A-6.4.2 Calculate volume of lime storage silo (30 days storage assumed).
VLS =
where
(12) (30
VLS = Volume of lime storage required, ft .
12 = Months/yr.
30 = Bulk density of hydfated lime in storage silo, Ib/ft .
A-6. 4. 3 Calculate combined capacity of two mixing tanks.
-' (sv)(pT) 2)
_
(DRY)
where
MTC = Total mixing tank capacity required, gal.
2 = Design factor.
A-6. 4. 4 Calculate capacity of lime feed system.
LFC =
(ALR) (2.0)
(DRY) (HPD) (0.167)
where
LFC - Total lime feed system capacity required, Ib/hr,
0.167 =1/6 = Assumed 5-min period of lime feeding divided by 30-min
detention period.
A-6.5 Process Design Output Data
A-6.5.1 Annual lime requirement, ALR, 1 b/yr.
A-6.5.2 Volume of lime storage silo, VLS, ft3.
269
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A-6.5.3 Combined capacity of two mixing tanks, MTC, gal.
A-6.5.4 Capacity of lime feed system, LFC, Ib/hr.
A-6.6 Quantities Cal cul ations
A-6.6.1 Calculate annual energy requirement for air mixing.
RFR = (MTC) (0.03) (97)
T7T48)
where
BER = Annual energy requirement for air mixing, kWhr/yr.
0.03 = Blower capacity factor based on 3 cfm/100 ft of tank volume.
97 = kWhr required annually per cfm of blower capacity.
A-6.6.2 Calculate total annual energy requirement.
E = BER (1.3)
where
E = Total annual energy requirement, kWhr/yr.
1.3 = Additional power factor for lime feeding and other minor energy
requirements.
A-6.6.3 Calculate annual labor requirement.
L = (DPY) (HPD) (0.5 +
where
L = Annual labor requirement, hr/yr.
= Labor hour factor.
A-6.7 Quantities Calculations Output Data
A-6.7.1 Annual energy requirement for air mixing, BER, kWhr/yr.
A-6.7.2 Total annual energy requirement, E, kWhr/yr.
A-6.7.3 Annual labor requirement, L, hr/yr.
270
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A-6.8 Unit Price Input Required
A-6.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-6.8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made MSEC I.
A-6.8,3 Cost of lime, LMCST, $/ton. Default value = $100/ton
(ENRCCI/4,006). •
A-6.8.4 Cost of lime storage silo(s), LSCST, $/ft3. Default value =
$7.40/ftd (ENRCCI/4,006).
A-6.8.5 Cost of mixing tanks, MTCST, including air mixing system, scrub-
ber, and piping, $/gal. Default value = $0.80/gal (MSECI/751).
A-6.8.6 Cost of lime feed system, LFCST, including all accessories,
$/lb/hr. Default value = $15/1 b/hr (MSECI/751).
A-6.8.7 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-6.8.8 Cost of energy, COSTE, $/kWhr. Default value * $0.09/kWhr
(ENRCCI/4,006).
A-6.9 Cost Calculations
A-6.9.1 Annual cost of lime.
rfKTiM - (AIR) (LHCST)
UU5ILP1 - 2,000
where
ACSTLM = Annual cost of lime, $/yr.
A-6.9.2 Cost of lime storage silo.
COSTLS = (VLS) (LSCST)
where
COSTLS = Cost of lime storage silo, $.
A-6.9.3 Cost of lime feed system with appurtenances.
COSTLF = (LFC) (LFCST)
271
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where
COSTLF = Cost of lime feed systems, $.
A-6.9.4 Cost of mixing tanks with appurtenances.
COSTMT = (NIC) (MTCST)
where
COSTMT = Cost of mixing tanks with appurtenances, $.
A-6.9.5 Annual cost of operation labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation labor, $/yr.
A-6.9.6 Annual cost of electrical energy.
COSTEL - (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-6.9.7 Total base capital cost.
TBCC = COSTLS + COSTLF + COSTMT
where
TBCC = Total base capital cost, $.
A-6.9.8 Annual maintenance material and supply cost.
COSTM = (TBCC) (0.15)
where
COSTM = Annual maintenance material and supply cost, $/yr,
272
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A-6.9.9 Annual cost of operation and maintenance.
COSTOM = COSTLM + COSTLB -t- COSTEL + COSTM
where
COSTOM = Annual cost of operation and maintenance, $/yr.
A-6.10 Cost Calculations Output Data
A-6.10.1 Annual cost of lime, COSTLM, $/yr.
A-6.10.2 Cost of lime storage silo, COSTLS, $.
A-6.10.3 Cost of lime feed system with appurtenances, COSTLF, $.
A-6.10.4 Cost of mixing tanks with appurtenances, COSTMT, $.
A-6.10.5 Annual cost of operation labor, COSTLB, $/yr.
A-6.10.6 Annual cost of electrical energy, COSTEL, $/yr.
A-6.10.7 Annual maintenance material and supply cost, COSTM, $/yr.
A-6.10.8 Total base capital cost, TBCC, $.
A-6.10,9 Total annual operation and maintenance cost, COSTOM, $/yr.
273
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APPENDIX A-7
THERMAL CONDITIONING OF SLUDGE
A-7.1 Background
Thermal conditioning, also known as Zimpro Process®, low-pressure oxida-
tion, and heat treatment, is a stabilization and conditioning process which
prepares sludge for dewatering without the use of chemicals. The sludge is
heated to temperatures from 290 to 410 °F under pressures of 150 to 400
Ib/in , with the addition of steam and sometimes air. During treatment, the
sludge is stabilized due to the hydrolysis of proteinaceous materials and
destruction of cellular tissues. In addition, the high temperatures and pres-
sures to which the sludge is subjected result in the release of bound water,
enhancing dewatering.
The thermal conditioning process is most applicable to biological sludges
that may be difficult to stabilize or condition by other means. However, the
process is generally limited to large treatment plants (>5 mgd) due to the
associated high capital and Q&M costs. In addition, the process requires
skilled personnel for operation and a rigorous preventative maintenance pro-
gram.
A major disadvantage associated with thermal conditioning results from
the high concentrations of soluble organic compounds and ammonia nitrogen in
the supernatant and filtrate recycle liquor. The recycle liquor can increase
the BOD load to an aeration system appreciably. In addition, the thermal con-
ditioning system and subsequent dewatering equipment will, in almost all
cases, require odor control facilities.
A-7..1.1 Process Design
The design of thermal conditioning systems is based on a number of fac-
tors such as sludge volume, percent volatile solids, detention time, and oper-
ating schedule. Process performance is a function of temperature, pressure,
and feed solids concentration. Typical values are shown below.
Parameter Value
Volatile solids destroyed 30-40 percent
Solids capture 95 percent
Effluent solids 35-50 percent
Temperature 290-410 °F
Pressure 150-400 Ib/in2g
Detention time 30-90 minutes
Steam consumption 600 lb/1,000 gal sludge
274
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Thermal conditioning systems are generally purchased from the manufac-
turer as package units. The package consists of sludge feed pumps, sludge
grinders, heat exchangers, reactors, boiler, gas separators, air compressors
(if necessary), and decanting tank. Equipment such as heat exchangers and
reactors are constructed of corrosion-resistant materials, usually stainless
steel.
Capital costs in the following algorithm include purchase and installa-
tion of the above-mentioned equipment, piping, controls, wiring, a single-
story building, and odor control systems. Costs do not include provisions for
treatment of the supernatant and filtrate recycle streams. The streams are
normally returned to the main treatment plant following preliminary treatment.
A-7.1.2 Algorithm Development
Fuel, electrical energy, and labor requirements in the following algo-
rithm are based on information from Reference 5, pages 300-13 through 300-34,
and Reference 7, pages A-224 and A-225. Base capital costs are based on Ref-
erence 7 (pages A-224 and A-225) and values obtained, from equipment manufac-
turers. Capital costs and electrical energy were fit to equations using a
multiple regression program.
A-7.2 Input Data
A-7.2.1 Daily sludge volume, SV, gal/day,
A-7.2.2 Hours per day process is operated, HPD, hr/day.
A-7.2.3 Days per year process is operated, DRY, days/yr.
A-7.3 Design Parameters
A-7.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user. No default value.
A-7.3.2 tours per day process is operated, HPD, hr/day. Default value =
20 hr/day.
A-7.3.3 Days per year process is operated, DPY, days/yr. Default value
= 365 days/yr.
A-7.4 Process Design Calculations
A-7.4.1 Sludge volume processed in gallons per minute.
ucy.- (SV) (365)
. (HPD) (DPY) (60)
where
MSV = Sludge volume, gal/min.
275
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A-7.5 Process Design Output Data
A-7,5.1 Sludge volume, MSV, gal/mi n,
A-7.6 Quantities Calculations
A-7.6.1 Fuel requirement. Calculations for the two most commonly used
fuels, fuel oil and natural gas, are shown below. Use only one
fuel type for cost estimating.
A-7.6.1.1 Annual fuel oil requirement.
FO = (MSV) (5.04) (DRY)
where
FO = Annual fuel oil requirement, gal/yr.
5.04 = Fuel oil consumption factor, gal fuel oil/day/gpm of
si udge feed.
A-7.6.1.2 Annual natural gas requirement.
N6 = (MSV) (700) (DRY)
where
•j
NG = Annual natural gas requirement, ft°/yr.
O
700 = Natural gas consumption factor, ft gas/day/gpm of sludge
feed.
A-7,6.2 Annual electrical energy requirement.
E = [- 0.0315 (MSV)2 + 28.6 (MSV) + 50.0] (DRY)
where
E * Annual electrical energy requirement, kWhr/yr.
A-7.6.3 Annual operation and maintenance labor requirement.
L = [0.141 (MSV) + 3.60] (DPY)
where
L = Annual operation and maintenance labor requirement, hr/yr.
276
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A-7.7 Quantities Calculations Output Data
A-7.7.1 Annual fuel requirement, FO, gal/yr, or natural gas requirement,
NG, ft3/yr.
A-7.7.2 Annual electrical energy requirement, E, kWhr/yr.
A-7.7.3 Annual operation and maintenance labor requirement, L, hr/yr.
A-7.8 Unit Price Input Required
A-7.8.1 Current Engineering News Record Construction Cost Index, ENRCCI,
at time cost analysis is made.
A-7.8.2 Current Marshall and Swift Equipment Cost Index, MSECI, at time
analysis is made.
A-7.8.3 Unit cost of fuel oil, COSTFO, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-7.8.4 Unit cost of natural gas, COSTNG, $/ft3. Default value =
10.006/ff3 (ENRCCI/4,006).
A-7.8.5 Unit cost of electricity, COSTE, $/kWhr. Default value = $0.09/
kWhr (ENRCCI/4,006).
A-7.8.6 Unit cost of labor, COSTL, $/hr. Default valve = $13.00/hr
(ENRCCI/4,006).
A-7.9 Cost Calculations
A-7.9.1 Annual cost of fuel.
COSTFU = (FO) (COSTFO)
or
COSTFU = (NS) (COSTNG)
where
COSTFU = Annual cost of fuel, $/yr.
A-7.9.2 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where '
COSTEL = Annual cost of electrical energy, $/yr,
277
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A-7.9.3 Annual operation and maintenance labor cost.
COSTLB = (L) (COSTL)
where
COSTLB = Annual operation and maintenance labor cost, $/yr.
A-7.9.4 Total base capital cost. Wet oxidation facilities are usually
purchased as a complete package directly from manufacturers.
Costs are largely a function of sludge volume, MSV, in gal/min.
TBCC - CO.229 (MSV)3 - 116.32 (MSV)2 + 30,264 (MSV) + 880,950]
where
TBCC =* Total base capital cost of wet oxidation stabilization facility, $.
A-7.9.5 Annual maintenance material and supply cost, COSTMS, is assumed
to be a function of total base capital cost, TBCC.
COSTMS = 0.02 (TBCC)
where
COSTMS = Total annual maintenance parts and materials cost, $/yr.
A-7.9.6 Annual operation and maintenance cost.
COSTOM = (COSTFU) + (COSTEL) + (COSTLB) + (COSTMS)
where
COSTOM = Annual operation and maintenance cost, $/yr.
A-7.10 Cost Calculation Output Data
A-7.10.1 Annual cost of fuel, COSTFU, $/yr.
A-7.10.2 Annual cost of electrical energy, COSTEL, $/yr.
A-7.10.3 Annual operation and maintenance labor cost, COSTLB, $/yr.
A-7.10.4 Total base capital cost of wet oxidation facility, TBCC, $.
A-7.10.5 Total annual operation and maintenance cost of wet oxidation
facility, COSTOM, $/yr.
278
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APPENDIX A-8
CENTRIFUGE DEWATERING
A-8.1 Background
Centrifuge dewatering is a process in which centrifugal force is applied
to promote the separation of solids from the liquid in a sludge. Dewatering
is accomplished through clarification and solids compaction. Depending upon
the physical properties of the sludge (particle size and density, temperature,
and sludge age), the solids concentration in the dewatered cake varies from 10
to 25 percent.
The selection and design of a centrifuge is dependent on a number of fac-
tors determined through a pilot test program. Process variables include the
feed flow rate, rotational speed of the centrifuge, differential speed of the
scroll, depth of the settling zone, chemical use, and the physical properties
of the sludge. Design parameters are established by individual equipment
manufacturers, and include maximum operating speed, feed inlet, and conveyor
and bowl type. Although there are numerous types of centrifuges available,
only two have found prominence in dewatering sludges: the imperforate basket
and the solid bowl conveyor.
The most common type of centrifuge used in wastewater sludge management
is the solid bowl, also referred to as a scroll centrifuge. Solid bowl cen-
trifuges are classified as either high g or 1ow g; high-g centrifuges operate
above 1,400 rpm, and 1ow-g centrifuges operate at less than 1,400 rpm. In the
solid bowl type, sludge is fed at a constant flow rate into a rotating bowl
where it separates into a dense cake containing the solids9 and a dilute cen-
trate stream. Centrate is usually returned to the primary clarifier or sludge
thickener.
Base capital costs in this algorithm include the purchase and installa-
tion of one or more 1 ow-g solid bowl centrifuges. The number of centrifuges
required is based on sludge flow, according to the following matrix:
SI udge Fl ow Number of
(gal/min) Centrifuges
£ 500 1
> 500 but <_ 1,000 2
> 1,000 but <_ 1,500 3
> 1,500 but <_ 2,000 4
279
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In addition, base capital costs include the construction of a building of suf-
ficient area to house the units and ancillary equipment; purchase and instal-
lation of pipe; and electrical instrumentation. O&M costs include labor,
electrical energy, and materials.
A-8.1.1 Al gorithm Devel opment
The following algorithm is based on capital costs and O&M costs and re-
quirements contained in Reference 6, pages 175 through 180; Reference 7, page
A-195; and from information supplied by equipment manufacturers. Costs and
O&M requirements synthesized from these references were fit to equations using
a multiple regression program. Costs and requirements are presented as func-
tions of sludge volume processed per minute.
A-8.2 Input Data
A-8.2.1 Daily sludge volume, SV, gal/day.
A-8.2.2 Hours per day process is operated, HPD, hr/day.
A-8.2.3 Days per year process is operated, DRY, days/yr.
A-8.3 Design Parameters
A-8.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user or the previous unit process. No default
value.
A-8.3.2 Hours per day process is operated, hr/day. Default value = 8
hr/day.
A-8.3.3 Days per year process is operated, DRY, days/yr. Default value
= 365 days/yr.
A-8.4 Process Design Cal cul ations
A-8.4.1 Sludge volume in gal/mi n.
MSV - . (SV) (365)
* (HPD) (DRY) (60)
where
MSV = Sludge volume in gal/mi n.
A-8.5 Process Design Output Data
A-8.5.1 Sludge volume, MSV, gal/mi n.
A-8.6 Quantities Calculations
A-8.6.1 Annual operation and maintenance labor requirement.
280
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A-8.6.1.1 If MSV < 70 gal/min, labor is calculated by:
L = 0.028 (MSV)2 + 0.265 (MSV) + 744
A-8.6.1.2 If 70_<_MSV < 500 gal/mi n, labor is calculated by:
L = 1.75 x ID"5 (MSV)3 - 0.019 (MSV)2 + 8.205 (MSV) + 426
A-8.6.1.3 If MSV >_ 500 gal/min, labor is calculated by:
L = [- 2.10 x 10"7 (MSV)3 + 6.6 x 10"4 (MSV)2 + 0.035 (MSV) + 1,686]
where
L = Annual operation and maintenance labor requirement, hr/yr.
A-8.6.2 Annual electrical energy requirement.
A-8.6.2.1 Process energy.
A-8.6.2.1.1 If MSV < 70 gal/min, process electrical
energy is calculated by:
PE = [- 5.91 (MSV)2 + 2,695 (MSV) + 500]
A-8.6.2.1.2 If 70_£MSV < 500 gal/min, process electri-
cal energy is calculated by:
PE = 6.671 x 10~4 (MSV)3 - 0.513 (MSV)2 + 2,041 (MSV) + 24,253
A-8.6.2.1.3 If MSV _>_ 500 gal/min, process electrical
energy is calculated by:
PE = 1.493 x 10"3 (MSV)3 - 5.313 (MSV)2 + 7,435 (MSV) - 1,557,500
where
i
PE = Annual process electrical energy required, kWhr/yr.
281
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A-8.6.2.2 Annual building energy.
A-8.6.2.2.1 If MSV < 70 gal/min, building electrical
energy is calculated by:
BE = [- 14.015 (MSV)2 -i- 1,867 (MSV) + 67,917]
A-8.6.2.2.2 If 70 _<_ MSV < 500 gal/min, building elec-
trical energy is calculated by:
BE = 1.748 x 10"3 (MSV)3 - 1.797 (MSV)2 + 675.6 (MSV) + 93,530
A-8.6.2.2.3 If MSV >_ 500 gal/min, building electrical
energy is calculated by:
BE = [- 1.110 x 10"5 (MSV)3 + 0.033 (MSV)2 + 118.4 (MSV) + 139,140]
where
BE = Annual building electrical energy required, kWhr/yr.
A-8.6.2.3 Total annual electrical energy required.
E = PE + BE
where
E = Electrical energy required, kWhr/yr.
A-8.7 Quantities Calculations Output Data
A-8.7.1 Annual operation and maintenance labor requirement, L, hr/yr.
A-8.7.2 Annual electrical energy requirement, E, kWhr/yr.
A-8.8 Unit Price Input Required
A-8,8.1 Current Engineering News Record Construction Cost Index, ENRCCI,
at time cost analysis is made.
A-8.8.2 Current Marshall and Swift Equipment Cost Index, MSECI, at time
cost analysis is made.
A-8.8.3 Unit cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
282
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A-8.8.4 Unit cost of electrical energy, COSTE, $/kWhr. Default value
$0.09/kWhr (ENRCCI/4,006).
A-8.9 Cost Calculations
A-8.9.1 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-8.9.2 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-8.9.3 Annual cost of maintenance parts and materials.
COSTPM = [1.92 x 10"5 (MSV)3 - 0.0055 (MSV)2 + 13.053 (MSV) + 2,113]
where
COSTPM = Annual cost of parts and materials, $/yr.
A-8.9.4 Total base capital cost.
A-8.9.4.1 If MSV;< 70 gal/mi n, total base capital cost is cal
culated by:
TBCC = [- 10.538 (MSV)2 + 3,023.6 (MSV) + 161,390]
A-8.9.4.2 If 70_<_MSV < 500 gal /mi n, total base capital cost is
cal culated by:
TBCC = [- 9.4 x 10"4 (MSV)3 - 0.5 (MSV)2 + 1,653 (MSV) + 217,840]
283
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A-8.9.4.3 If MSV >_ 500 gal/mi n, total base capital cost; is cal
culated by:
TBCC = [6.8 x 10"4 (MSV)3 - 2.5 (MSV)2 * 3,803 (MSV) - 520,470] ^
where
TBCC = Total base capital cost, $.
A-8.9.5 Total annual operation and maintenance cost.
COSTOM = (COSTEL) + (COSTLB) + (COSTPM)
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-8.10 Cost Calculations Output Data
A-8.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-8.10.2 Annual cost of electrical energy, COSTEL, $/yr.
A-8.10.3 Annual cost of parts and materials, COSTPM, $/yr.
A-8.10.4 Total base capital cost for centrifuge dewatering, TBCC, $.
A-8.10.5 Total annual operation maintenance cost for centrifuge dewater-
ing, COSTOM, $/yr.
284
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APPENDIX A-9
BELT FILTER DEWATERING
A-9.1 Background
Belt filters have become increasingly popular in the United States, often
selected as the method for dewatering sludges at new treatment plants. This
popularity is due to the high dewatering capabilities and low power require-
ments of the process.
Belt filters employ single or double moving belts made of woven synthetic
fiber to dewater sludges continuously. The belts pass over and between roll-
ers which exert increasing pressure on the sludge as it moves with the belts.
Sludges are dewatered initially through the action of capillarity and gravity,
and afterwards by increasing pressure and shear force over the length of the
filtration zone. The dried cake is removed from the filter belt by a flexible
scraper. A second scraper and 'sprayed water are used to clean the belt.
biudge conditioning is important in tms process in order to achieve
optimal dewatering performance. Costs obtained in this algorithm do not
include conditioning. Those costs may be obtained using the algorithms in
Appendices A-13, A-14, and A-15.
Process design is based on solids and hydraulic loading. However, solids
loading appears to be the more critical of the two. Belt filters are pur-
chased from the manufacturer in standard belt widths. In this algorithm, sin-
gle or multiple units of 0.5-, 1-, and 2-meter widths are considered. To
estimate the width of a belt filter, the loading rate (Ib sludge/meter/hr) is
the key design parameter, as shown in the table below.
Influent Suspended Solids (%') 1-2 3-4 5-6
Loading Rate (dry solids Ib/hr/meter 400-600 600-800 800-900
of belt width)
Capital costs in this algorithm include purchase and installation of one
or more belt press units and ancillary equipment, and a building t.o house belt
presses with adequate room for safe operation and maintenance. Annual O&M
costs include labor, electrical energy, and parts and materials.
285
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A-9.1.1 Algorithm Development
This algorithm is based on design and cost information obtained from Ref-
erence 6, pages 181 through 183, and information supplied by equipment manu-
facturers. Costs and O&M requirements obtained were fit to equations using a
multiple regression program.
A-9.2 Input Data
A-9.2.1 Daily sludge volume, SV, gal/day.
A-9.2.2 Sludge suspended solids concentration, SS, percent.
A-9.2.3 Sludge specific gravity, SSG, unit!ess.
A-9.2.4 Sludge dry solids loading rate per meter width of the belt
press, BFLR, Ib/meter/hr.
A-9.2.5 Hours per day process is operated, HPD, hr/day.
A-9.2.6 Days per year process is operated, DPY, days/yr.
A-9.3 Design Parameters
A-9.3.1 Daily sludge volume, SV, gal/day. This input value must be pro-
vided by the user. No default value.
A-9.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value. Be sure
to include SS added by conditioning chemicals.
A-9.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is calcu-
lated as follows:
SSG = !
100 - SS (SS)
100 " (1.42) (100)
A-9.3.4 Sludge dry solids. Loading rate per meter width of the belt
press, BFLR, Ib/hr. This value is a function of suspended
solids in the feed sludge. Default values are 500 for 2 percent
SS, 650 for 4 percent SS, and 800 for 6 percent SS.
A-9.3.5 Hours per day process is operated, HPD, hr/day. Default value =
8 hr/day.
A-9.3.6 Days per year process is operated, DPY, days/yr. Default value
= 365.
286
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A-9.4 Process Design Calculations
A-9.4.1 Calculate dry solids dewatered per day.
_ (SV) (SS) (SSG) (8.34)
(100)
where
DSS = Dry solids dewatered per day, Ib/day.
8.34 = Density of water, Ib/gal,
A-9.4. 2 Calculate the total width of the belt filter needed to dewater
the sludge at the specified loading rate. Costs are based on
the use of one or more 0.5-, l-» and 2-meter-wide unit belt fil-
ters. The total width required is sufficient to estimate the
costs regardless of the number of units used.
TRFW =
_-_
(BFLR) (HPD) (DPY)
where
TBFW = Total belt filter width, meters.
A-9.5 Process Design Output Data
A-9.5.1 Dry suspended solids dewatered per day, DSS, Ib/day.
A-9.5. 2 Total belt filter .width, TBFW, meters.
A-9.6 Quantities Calculations
A-9.6.1 Annual operation and maintenance labor required.
A-9.6. 1.1 If TBFW _< 0.5 meters, labor is calculated by:
L = 1 773 f(TBFW)1
L i,//J j^ y^' I
A-9.6. 1.2 If TBFW > 0.5 meters, labor is calculated by:
L = [- 0.34 (TBFW)3 + 3,734 (TBFW)2 + 441.5 (TBFW) + 619]
where
L = Annual operation and maintenance labor required, hr/yr.
287
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A-9.6.2 Annual electrical energy required,
A-9.6.2.1 If TBFW _^ 0.5 meters, electrical energy is calculated
by:
E = 22,065
A-9.6.2. 2 If TBFW > 0.5 meters, electrical energy is calculated
by:
E = [- 5.42 (TBFW)3 + 234.6 (TBFW)2 + 16,020 (TBFW) + 13,997]
where
E = Annual electrical energy required, kWhr/yr.
A-9.7 Quantities Calculations Output Data
A-9.7.1 Annual operation and maintenance labor required, L, hr/yr.
A-9.7. 2 Annual electrical energy required, E, kWhr/yr,
A-9.8 Unit Price Input Required
A-9.8.1 Current Engineering News Record Construction Cost Index, ENRCCI,
at time cost analysis is made.
A-9.8. 2 Current Marshall and Swift Equipment Cost Index, MSEC!, at time
cost analysis is made.
A-9.8. 3 Cost of operation and maintenance labor, COSTL, $/hr. Default
value = $13.00/hr (ENRCCI/4,006).
A-9.8. 4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-9.9 Cost Calculations
A-9.9.1 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of labor, $/yr.
288
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A-9.9.2 Annual cost of electrical energy, $/yr.
COSTEL « (E) (COSTE)
where
COSTEL = Annual cost of electrical energy.
A-9.9.3 Annual cost of parts and materials.
A-9.9.3.1 If TBFW <_ 0.5 meters, annual cost of parts and mate-
rials is calculated by:
COSTPM = 1,784 I -UE™1 -___
L °-* J t^
A-9.9.3.2 If TBFW > 0.5 meters, annual cost of parts and mate-
rials is calculated by:
COSTPM = [- 0.708 (TBFW)3 + 30.6 (TBFW)2 + 2,371 (TBFW) + 1,184]
where
COSTPM = Annual cost of parts and materials, $/yr.
A-9.9.4 Total base capital cost.
A-9.9.4.1 If TBFW <_ 0.5 meters, total base capital cost is cal
culated by:
TBCC = [243,000]
A-9.9.4.2 If TBFW > 0.5 meters, total base capital cost is cal-
culated by:
TBCC = [- 158.6 (TBFW)3 + 5,496 (TBFW)2 + 98,269 (TBFW) + 192,630]
where
TBCC = Total base capital cost, $.
A-9.9.5 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTPM
289
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where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-9.10 Cost Calculations Output Data
A-9.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-9.10.2 Annual cost of electrical energy, COSTEL , $/yr.
A-9.10.3 Annual cost of parts and materials, COSTPM, $/yr.
A-9.10.4 Total base capital cost, TBCC, $.
A-9.10,5 Total annual operation and maintenance cost, COSTOM, $/yr.
290
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APPENDIX A-10
RECESSED PLATE FILTER PRESS DEWATERING
A-10.1 Background
Recessed plate pressure filters consist of numerous parallel plates,
recessed on both sides with a filter cloth hung over the face of each plate.
The number of plates is determined by sludge volume and cycle time. The pro-
cess, which operates in a batch mode, uses high pressures to force water from
the sludge.
The process operates by pumping conditioned sludge into the void spaces
between each plate where a sludge cake forms. Pressure within the chamber
builds up to approximately 225 to 250 psi, and is maintained for a 1- to 4-
hour period. Filtrate is collected in drainage ports and discharged to a com-
mon drain. As solids accumulate in the press, the head loss increases with a
subsequent decrease in filtrate flow. The pressure cycle ends when the cham-
bers are completely filled, and the filtrate flow approaches zero. The plates
are then opened, and the filter cake drops onto conveyors or into hoppers for
removal.
In this dewatering process, sludge conditioning is imperative. Costs for
conditioning are not included in this algorithm. These costs may be obtained
using the algorithms in Appendices A-13, A-14, and A-15.
Due to relatively high capital and O&M costs, this dewatering process is
usually considered for sludge of poor dewaterability and/or where a final cake
solids content over 30 percent is desired, as necessary. Filter presses are
ideal for dewatering sludges in preparation for incineration. The cyclic
operation may be a disadvantage at some treatment facilities. Several manu-
facturers have developed new designs which have minimized or virtually elimi-
nated cyclical operation.
In this algorithm, filter presses with a minimum total chamber volume per
unit of 10 cu ft and a maximum; of 450 cu ft are assumed. The number of units
required is based on total chamber volume according to the following table:
Total Chamber Number
Volume, cu ft of Units
£ 450 1
> 450 but £ 900 2
> 900 but _£ 1,200 3
> 1,200 but < 1,500 4
291
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Capital costs in this algorithm include purchase and installation of fil-
ter press units; feed pumps, including one standby unit; and building for
housing the units. Operation and maintenance costs include labor, electrical
energy, and maintenance materials.
A-10.1.1 Algorithm Development
The following algorithm uses total chamber volume as the variable in
estimating costs and O&M requirements. Base capital and O&M costs were de-
rived from information contained in Reference 6, pages 187 through 189. Addi-
tional cost information was supplied by equipment manufacturers.
A-10.2 Input Data
A-10.2.1 Daily sludge volume, SV, gal/day.
A-10.2.2 Sludge suspended solids concentration, SS, percent.
A-10.2.3 Sludge specific gravity, SSG, unitless.
A-10.2.4 Hours per day process is operated, HPD, hr/day.
A-10.2.5 Days per year process is operated, DPY, days/yr.
A-10.2.6 Cake solids content, CSC, percent.
A-10.2.7 Filter cycle time, FCT, hr/cycle.
A-10.3 Design Parameters
A-10.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-10.3,2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value. Ete sure
to include SS added by conditioning chemicals.
A-10.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is cal-
culated as follows:
SSG = -> 1
100 - SS (SS)
100 (1.42) (100)
where
SSG * Sludge specific gravity, unitless.
1.42 * Assumed sludge solids specific gravity.
A-10.3.4 Hours per day process is operated, HPD, hr/day. Default value
= 8 hr/day.
292
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A-10.3.5 Days per year process is operated, DPY, days/yr. Default value
= 365 days per year.
A-10.3.6 Cake solids content, CSC, percent. This input value should be
provided by the user, if possible, including time for cleanup
between cycles. The attainable cake suspended solids concen-
tration is in the range of 30 to 50 percent. Default value =
40 percent.
A-10.3,7 Filter cycle time, FCT, hr/cycle. This input value should be
provided by the user if possible. Range is 1 to 4 hr. If not
available, default cycle times are as follows:
FCT,
Percent Solids hr/cycle
2 2.5
4 2.2
6 2.0
A-10.4 Process Design Calculations
A-10.4.1 Calculate the dry sludge solids dewatered per day.
DSS - JSV) (SS) (SSG) (8.34)
u - - -
where
DSS - Dry sludge solids dewatered per day, Ib/day.
8.34 = Density of water, Ib/gal.
A-10.4. 2 Calculate the cake volume.
Cv -
"
(100)
(CSC) (71)
where
CV = Cake volume, ft3/day»
71 = Assumed weight of filter cake, lb/ft-%
A-10.4. 3 Calculate the total chamber volume required, ft
TCV -
293
-------
where
TCV = Total chamber volume required, ft**.
A-10.5 Process Design Output Data
A-1Q.5.1 Total dry solids produced per day, DSS, Ib/day.
o
A-10.5. 2 Cake volume produced per day, CV, ft°/day.
A-10.5. 3 Total chamber volume required, TCV, ft3.
A-10.6 Quantities Calculations
A-10.6.1 Annual operation and maintenance labor requirement.
A-10.6. 1.1 If TCV _<_ 10 ft3, labor requirement is calculated
by:
^ (1.455)
[Ttf
(TCV)
A-10.6. 1.2 If 10 < TCV <_ 450 ft3, labor requirement Is calcu-
lated by:
L = [- 2.07 x 10"4 (TCV)2 + 0.17 (TCV) + 1,455]
A-10.6. 1.3 If 450 < TCV £ 900 ft3, labor requirement Is calcu-
lated by:
L = 3.1 (TCV - 900) + 2,884
A-10.6. 1.4 If TCV > 900 ft3, labor requirement is calculated
by:
L = [- 6.7 x 10"3 (TCV)2 + 18.96 (TCV) - 8,696]
where
L = Annual labor requirement, hr/yr.
A-10.6. 2 Annual electrical energy requirement.
A-10.6. 2.1 If TCV <_ 10 ft3, electrical energy requirement is
calculated by:
E - 58,000
294
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A-10.6.2.2 If TCV > 10 ft3, electrical energy requirement is
calculated by:
E - [- 5.49 x 10~6 (TCV)3 + 9.83 x 10"3 (TCV)2 + 583.8 (TCV) + 50,956]
where
E = Annual electrical energy requirement, kWhr/yr.
A-10.7 Quantities Calculations Output Data
A-10.7.1 Annual operation and maintenance labor requirement, L, hr/yr.
A-10.7.2 Annual electrical energy requirement, E, kWhr/yr.
A-10.8 Unit Price Input Required
A-10.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI, at time cost analysis is made.
A-10.8.2 Current Marshall and Swift Equipment Cost Index, MSECI, at time
cost analysis is made.
A-10.8.3 Unit cost of labor, COSTL, $/hr. Default value - $13.QO/hr
(ENRCCI/4,006).
A-10.8.4 Unit cost of electrical energy, CQSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-10.9 Cost Calculations
A-10.9.1 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-10.9.2 Annual cost of electrical energy.
COSTEL - (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
295
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A-10.9.3 Annual cost of maintenance parts and materials.
A-10.9.3.1 If TCV < 10 ft3, cost of parts and materials is
calculated by:
(2.880) (TCV) 1 MSECI
_ ^
A-10.9.3. 2 If TCV _> 1° ft3' cost of parts and materials is
calculated by:
COSTPM = [- 1.63 x 10"5 (TCV)3 + 0.0358 (TCV)2 + 24.9 (TCV) + 2,452] M^
where
COSTPM = Annual cost of maintenance parts and materials, $/yr.
A-10.9.4 Total base capital cost.
A-10.9.4.1 If TCV < 10 ft3, base capital cost is calculated
by:
TBCC = (235,320)
/ *JX
A-10.9.4.2 If TCV 2. 1° ft3, base capital cost is calculated
by:
TBCC = [- 8.632 x 10~4 (TCV)3 + 1.875 (TCV)2 + 1,997 (TCV) + 204,815]
where
TBCC = Total base capital cost, $.
A-10.9.5 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTPM
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-10.10 Cost Calculations Output Data
A-10.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
296
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A-10.1Q.2 Annual cost of electrical energy, COSTEL, $/yr.
A-10.10.3 Annual cost of parts and materials, COSTPM, $/yr.
A-10.10.4 Total base capital cost for recessed plate pressure filter
dewatering, TBCC, $.
A-10.10.5 Total annual operation and maintenance cost for recessed plate
pressure filter dewatering, COSTOM, $/yr.
297
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APPENDIX A-ll
VACUUM FILTER DEWATERIN6
A-ll.l Background
Vacuum filtration is a widely used method for mechanical dewatering of
wastewater sludges, though it is seldom selected now for new treatment plants.
Vacuum filtration is a continuous process consisting of a rotating drum which
is radially divided into compartments. The outside of the drum is covered by
a woven fabric or other filter medium, a portion (about 20 to 40 percent) of
which is submerged in sludge contained in a vat below the drum. Vacuum (10 to
26 inches of mercury) is alternately applied to the submerged portion of the
drum. As a result, water is drawn into the drum, and a cake forms on the fil-
ter medium. As the filter rotates, the vacuum is continued, and further mois-
ture reduction occurs as air is drawn through the cake into the drum. Before
the filter cake reaches the sludge vat again, the sludge cake is broken off by
blades and/or rollers. The cake drops onto a conveyor and is removed for
ultimate disposal.
Chemical conditioning with lime, ferric chloride, and/or organic poly-
electrolytes is usually a necessary step prior to sludge vacuum filtration.
Costs obtained in this algorithm do not include conditioning. These costs may
be obtained using the algorithms in Appendices A-13, A-14, and A-15.
The design of vacuum filtration systems is based on the solids loading
rate which is usually determined through laboratory testing. A conservative
rate of 3.5 Ib/ft^/hr has been widely used in process design. Actual operat-
ing loading rates typically vary between 2 and 10 Ib/ftvhr. The low values
represent filtration of fresh and digested activated sludge; the high values
are typical for raw primary sludge or mixed primary sludge plus trickling fil-
ter humus. Cake solids typically range from 12 to 17 percent.
Vacuum filtration facilities are generally sold as a package by various
filter manufacturers. The package normally includes vacuum pumps, sludge feed
pumps, filtrate pumps, sludge conditioning tanks, chemical feed pumps, and
belt conveyors that transport dewatered filter cake. Capital costs in this
cost algorithm include purchase and installation of one or more vacuum fil-
ters, appurtenant equipment, and construction of a building to house the
units. O&M costs include labor, electricity, and parts and materials.
A-ll.1.1 Algorithm Development
Cost equations in the following algorithm were developed by accessing the
existing CAPDET program. The CAPDET algorithm for vacuum filtration is found
in Reference 1, pages 2.65-1 through 2.65-17. Values were obtained by varying
sludge volume and suspended solids concentration entering the vacuum filter.
298
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In some cases, CAPDET was found to overestimate costs and O&M requirements
when compared with data in the literature. Therefore, costs and O&H require-
ments are based on information provided by a number of additional cost
sources, namely, Reference 4, pages 9.27 through 9.45; and Reference 6, page
185. Costs and O&M requirements were fit to an equation using a multiple
regression program,
A-11.2 Input Data
A-11,2.1 Daily sludge volume, SV, gal/day.
A-11.2.2 Sludge suspended solids, SS, percent.
A-11.2.3 Sludge specific gravity, SSG, unitless.
A-11.2.4 Sludge loading rate, SLR, Ib/ft2/hr.
A-11.2.5 Hours per day process is operated, HPD, hr/day.
A-11.2.6 Days per week process is operated, DPW, days/yr.
A-11.3 Design Parameters
A-ll.3.1 Daily sludge volume, SV, gal/day. This value must be input by
the user or the previous unit process. No default value. Be
sure to include volume added by conditioning chemicals.
A-11.3.2 Sludge suspended solids, SS, percent. This value must be input
by the user or the previous unit process. No default value.
Be sure to include solids added by conditioning chemicals.
A-11.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is cal-
culated as follows:
SSG -
100 - SS + (SS)
100 (1.42) (100)
where
SSG = Sludge specific gravity, unit!ess.
1.42 = Assumed sludge solids specific gravity.
A-11.3.4 Sludge loading rate, SLR, Ib/ft2/hr. Default value = 5 lb/
ft2/hr.
A-11.3.5 Hours per day process is operated, HPD, hr/day. Default value
= 8 hr/day.
A-11.3.6 Days per year process is operated, DPY, days/yr. Default value
= 365 days/yr.
299
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A-11.4 Process Design Calculations
A-ll.4.1 Calculate total filter area.
TFA - (SVMSSMSSG) (8.34) (365)
irrt _ ^i0()j (SLR) (HPU) (DFY)
where
TFA = Total filter area, ft2.
8.34 = Density of water, Ib/gal.
A-11.4. 2 Calculate dry solids produced.
- (SV) (S3) (SSG) (8.34) (365)
" (DPY)
where
TDSS = Daily dry solids produced, tons/day.
A-11.5 Process Design Output Data
A-ll.5.1 Required filter area, TFA, ft2.
A-11.5. 2 Daily dry solids produced, DSS, tons/day.
A-11.6 Quantities Calculations
A-ll.6.1 Filter selection. Units must be one of the following sizes,
which are commercially available: 60, 85,, 100, 125, 150, 200,
250, 300, 360, 430, 500, 575, 675, 750 ft*.
A-11.6. 1.1 If the total filter area is less than 750 ft,2, only
one filter will be used. The total filter area
(TFA) should be compared to the commercially avail-
able units (CFA), and the smallest available unit
which is larger than TFA should be selected.
A-11.6. 1.2 If the total filter area is greater than 750 ft2, a
minimum of two filters will be used. Selection of
the correct filter size must be done bv trial and
error. If TFA is greater than 750 ft% increase
the number of filters by one and calculate the unit
filter area (AF). If AF £ 750, the choice will be
made as follows: Select the smallest standard size
which is greater than AF; if (CFA x NF) is larger
than TFA by more than 10 percent, increase the num-
ber of filters by 1 and repeat the procedure; if
not, AF = CFA.
300
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A-ll.6.2 Calculate total surface area of selected commercially available
vacuum filter(s).
CTFA = (CFA) (NF)
where
CTFA = Total surface area of selected commercially available vacuum
fllter(s), ft2.
A-ll.6.3 Calculate housing area required for filters.
AB = [- 5.9 x 10"8 (CTFA)3 - 2.3 x 10~5 (CTFA)2 + 1.69 (CTFA) + 1,277]
«
where
p
AB = Area of the building, ft .
A-ll.6.4 Annual operation labor requirement.
A-ll.6.4.1 If 0.01 £ TOSS <_ 0.09 tons/day, operation labor is:
OL = 520
A-ll.6.4. 2 If 0.09 < TDSS <_ 9 tons/day, operation labor is
calculated by:
OL = 1,760 (TDSS)0'504
A-ll.6.4. 3 If 9 < TDSS j< 300 tons/day, operation labor is cal-
culated by:
OL •- 1,200 (TDSS)0-734
where
OL = Annual operation labor requirement, hr/yr.
A-ll.6.5 Annual maintenance labor requirement.
A-ll.6.5.1 If 0.01 <_ TDSS _< 0.09 tons/day, maintenance labor
is:
ML = 64
301
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A-ll.6.5.2 If 0.09 < TDSS <_ 9 tons/day, maintenance labor is
calculated by:
ML = 240 (TDSS)0-548
A-ll.6.5.3 If 9 < TDSS _< 300 tons/day, maintenance labor is
calculated by:
ML = 136 (TDSS)0'808
where
ML = Annual maintenance labor requirement, hr/yr.
*
A-ll.6.6 Installation labor requirement.
A-ll.6.6.1 If CFA < 400 ft2, installation labor is calculated
by:
IL = [544 -i- 0.32 (CFA)] (NF)
A-ll.6.6.2 If CFA _>_ 400 ft2, installation labor is calculated
by:
IL - [476 + 0.48 (CFA)] (NF)
where
IL = Installation labor requirement, hr.
A-ll.6.7 Annual electrical energy requirement.
E = 28,000 (DSS)0'933
where
E = Annual electrical energy requirement, kWhr/yr.
A-11.7 Quantities Calculations Output Data
A-ll.7.1 Filter area of the commercial unit selected, CFA, ft2.
A-11.7.2 Number of filters, NF, unitless.
302
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A-ll.7.3 Total surface area of selected commercially available vacuum
filter, CTFA, ft2.
A-ll.7.4 Area of building, AB, ft2.
A-ll.7.5 Annual operation labor requirements, OL, hr/yr.
A-ll.7.6 Maintenance labor requirement, ML, hr/yr.
A-ll.7.7 Installation labor requirement, IL, hr.
A-ll.7.8 Annual electrical energy requirement, E, kWhr/yr.
A-11.8 Unit Price Input Required
A-ll.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-11.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSECI.
A-11.8.3 Cost of standard size 300 ft2 vacuum filter, COSTSF, $. De-
fault value = $200,000 (ENRCCI/4,006).
A-11.8.4 Cost of building, construction, COSBC, $70/ft2 (ENRCCI/4,006).
A-11.8.5 Cost of installation labor, COSTIN, $/hr. Default value =
$18.00/hr (ENRCCI/4,006).
A-11.8.6 Cost of operation and maintenance labor, COSTL, $/hr. Default
value = $13.00/hr (ENRCCI/4,006).
A-11.8.7 Cost of electricity, COSTE, $/kWhr. Default value = $0.09/kWhr
(ENRCCI/4,006).
A-11.9 Cost Calculations
A-ll.9.1 Cost factor, expressed as a percent of standard size filter.
COSTR = 52 + 0.16 (CFA)
where
COSTR = Cost factor, expressed as a percent of standard size filter cost.
A-11.9.2 Cost of vacuum filter. This cost includes the cost of the
vacuum filter, vacuum pump, filtrate pump, filtrate fork,
sludge pump, conveyor belt, electric motors, and control panel.
COSTEO =.(COSTSF) (COSTR) (NF)
OUO.C^
303
-------
where
COSTEQ = Purchase cost of vacuum filter and accessories, $.
A-ll.9.3 Cost of filter building.
COSTH = (AB) (COSTBC)
where
COSTH = Cost of building, $.
A-ll.9.4 Filter installation cost.
ICOST = (IL) (COSTIN)
where
ICOST = Filter installation cost, $.
A-ll.9.5 Other equipment installation costs. This includes costs for
installation of vacuum pump, filtrate pump, filtrate tank,
sludge tank, sludge pump, conveyor belt, electrical panel, and
piping.
OICOST = (0.60) (COSTEQ)
where
OICOST = Other equipment installation costs, $.
A-ll.9.6 Annual cost of operation and maintenance labor.
COSTLB = (OL + ML) (COSTL)
where
COSTLB = Total cost of labor for operation and maintenance, $/yr.
A-ll.9.7 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
304
-------
where
COSTEL = Annual cost of electrical energy, $/yr.
A-ll.9.8 Annual cost of parts and materials.
COSTPM = (COSTEQ + ICOST + OICOST) (0.15)
where
COSTPM = Annual cost of parts and materials, $/yr.
A-ll.9.9 Total base capital cost.
TBCC = COSTEQ + COSTH + ICOST + OICOST
where
TBCC = Total base capital cost.
A-ll.9.10 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTPM
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-11.10 Cost Calculations Output Data
A-ll.10.1 Purchase cost of vacuum filter and accessories, COSTEQ, $.
A-11.10.2 Cost of building, COSTH, $.
A-11.10.3 Filter installation cost, ICOST, $.
A-11.10.4 Other equipment installation costs, OICOST, $.
A-11.10.5 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-11.10.6 Annual cost of electrical energy, COSTEL, $/yr.
A-11.10.7 Annual cost of parts and materials, COSTPM, $/yr.
A-11.10.8 Total base capital cost, TBCC, $.
A-11.10.9 Annual cost of operation and maintenance, COSTOM, $/yr.
305
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APPENDIX A-12
SLUDGE DRYING BED DEWATERING
A-12.1 Background
Sludge drying beds are commonly used at small treatment plants, since
they require less frequent operator attention, use little energy, are less
sensitive to influent solids concentration, and produce a drier sludge than
mechanical devices. The limitations of this process are that it requires a
large land area, requires stabilized sludge to prevent nuisance odors, is
sensitive to climate, and is more labor-intensive than mechanical dewatering.
As a consequence of the frequent downtime and high capital and operating costs
of mechanical systems, however, drying bed dewatering has become a viable
option at medium and large facilities where adequate land is available. More-
over, design improvements such as the use of chemical conditioning and mechan-
ical sludge removal have made sludge drying bed dewatering more attractive.
Although there are many types of drying beds (paved, wedge-wire, and
vacuum-assisted), sand drying beds are the most common. In this process,
sludge is dewatered in an open or covered bed primarily through drainage and
evaporation. Water drains through the sludge into sand where it is removed
through underdrains. Additional sludge drying is accomplished through evapo-
ration; therefore, drying time is affected by climate. Areas of high rainfall
and/or high humidity may have a detrimental effect on drying. Natural freez-
ing of sludges in northern climates has been reported to improve elewater-
ability.
Once the sludge has achieved the required dryness, it is manually or
mechanically removed using front-end loaders or truck-mounted vacuum removal
systems. Periodically, sand must be replaced and graded.
Chemically conditioned sludges offset unpredictable weather conditions
and variable sludge characteristics. In addition, chemical conditioning
improves the drying capabilities of many sludges. Costs for conditioning are
not Included in this algorithm. These costs may be obtained using the algo-
rithms 1n Appendices A-13, A-14, and A-15.
Drying beds were traditionally designed using per capita area criteria
for sizing. Values ranged from 1.0 to 3.0 ft2 per capita, depending on the
type and solids content of the applied sludge. The currently accepted crite-
rion for sizing drying beds is the solids loading rate. Typical requirements
vary from 10 to 40 Ib dry solids/ftVyr. In the United States, local regula-
tory agencies have established guidelines or standards for the minimum area of
sludge drying bed required as_a function of dry sludge solids applied per year
(e.g., 20 Ib of dry sol ids/ffVyr).
306
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The following algorithm is based on construction of uncovered sand drying
j using the following assumptions:
Depth of gravel = 9 inches.
Depth of sand = 9 inches.
Height of concrete dividing walls = 2 ft.
Diesel fuel consumption of front-end loader = 4 gal/hr.
Annual si udge removal frequency - 20 times/yr.
Sludge removal and bed preparation time = 3 hr/4,000 ft .
Capital costs include purchase of land, excavation and site work, instal-
lation of drain pipe and valves, construction of steel reinforced concrete
dividing walls, and purchase of one or more front-end loaders. O&M costs
include labor, diesel fuel, periodic replacement of sand, and replacement
parts and materials.
A-12.1.1 Algorithm Devel opment
Costs and O&M requirements in this algorithm were based on design experi-
ence and information obtained from various references. Capital costs were
obtained from Reference 6, page 193, and Reference 7, page A-197. Labor,
diesel, and maintenance material requirements were estimated from information
in Reference 6, pages 194 and 195.
A-12.2 Input Data
A-12.2.1 Daily sludge volume, SV, gal/day.
A-12.2.2 Sludge suspended sol ids concentration, SS, percent.
A-12.2.3 Sludge specific gravity, SSG, unit! ess.
A-12.2.4 Sludge drying bed loading, DBA, Ib dry sol ids/ft2/yr.
A-12.3 Design Parameters
A-12.3.1 Daily sludge volume, SV, gal/day. This value must be input by
the user. No default value.
A-12.3.2 Sludge suspended solids concentration, SS, percent. This value
must be input by the user. No default value.
A-12.3.3 Sludge specific gravity, SSG, unit! ess. Default value is
calculated using the following equation:
SSG -
ess
.42)
100 (1.42) (100)
where
SSG = Specific gravity of sludge, unit!ess.
1.42 = Specific gravity of sludge solids, unitless.
307
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A-12.3.4 Sludge drying bed area, DBA, Ib dry soli ds/ft2/yr. This value
should be input by the user, if possible, from state regulatory
requirements. Most states have requirements. Default values
are:
If SS = 2 percent, DBA = 15 Ib dry solids/ft2/yr.
If SS - 4 percent, DBA = 22 Ib dry solids/fWyr.
If SS = 6 percent, DBA = 28 Ib dry solids/ft2/yr.
If SS = 8 percent, DBA = 33 Ib dry solids/ft2/yr.
A-12.4 Process Design Calculations
A-12.4.1 Calculate dry sludge solids dewatered per year.
nss - (SV) (365) (8.34) (SS) (SSG)
U55 --» (100)
where
DSS = Dry sludge solids dewatered, Ib/yr.
8.34 = Density of water, Ib/gal.
A-12.4. 2 Calculate area of sludge drying beds required.
A - _____ (DSS)
A ~ f DBA) (1,0007
where
A = Area of sludge drying beds required in 1,000 ft2.
A-12.5 Process Design Output Data
A-12.5.1 Dry sludge solids dewatered, DSS, Ib/yr.
A-12.5. 2 Area of sludge drying beds required, A, 1,000 ft2.
A-12.6 Quantities Calculations
A-12.6.1 Calculate total land area required.
TLA - (1.5) (A)
i LA 43l5g
where
TLA = Total land area required, acres.
1.5 = Factor to account for additional area required for buffer and
equipment storage.
43.56 = Factor to convert 1,000 ft2 to acres.
308
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A-12.6.2 Calculate annual operation and maintenance labor requirement.
L = 6.87 x 10"6 (A)3 - 6.45 x 10"3 (A)2 + 15.3 (A) + 18
where
L = Annual operation and maintenance labor requirement, hr/yr,
A-12.6.3 Calculate annual diesel fuel requirement.
FU = 1.48 x 10~5 (A)3 - 0.018 (A)2 + 52 (A) + 15
where
FU = Annual diesel fuel requirement, gal/yr.
A-12.7 Quantities Calculations Output Data
A-12.7.1 Total land area required, TLA, acres.
A-12.7.2 Annual operation and maintenance labor requirement, L, hr/yr.
A-12.7.3 Annual diesel fuel requirement, FU, gal/yr.
A-12.8 Unit Price Input Required
A-12.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI, at time cost analysis is made.
A-12.8.2 Current Marshall and Swift Equipment Cost Index, MSEC I, at time
cost analysis is made,
A-12.8.3 Unit cost of land required, LANDCST, $/acre. Default value =
$3,000/acre.
A-12.8.4 Unit cost of labpr, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-12.8.5 Unit cost of diesel fuel, COSTDF, $/gal. Default value »
$1.30/gal (ENRCCI/4,006).
A-12.9 Cost Calculations
A-12.9.1 Cost of land for sludge drying bed site.
COSTLAND - (TLA) (LANDCST)
309
-------
where
COSTLAND = Cost of land for sludge drying bed site, $.
A-12.9.2 Construction cost of sludge drying beds.
COSTSDB = [1.52 x 10"4 (A)3 - 1.157 (A)2 + 3,425 (A) + 27,742] ENRCCI
4,006
where
COSTSDB = Construction cost of sludge drying beds, $.
A-12. 9. 3 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-12. 9. 4 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-12. 9. 5 Annual cost of maintenance parts and materials.
COSTPM = [- 1.61 x 10"6 (A)3 + 0.00297 (A)2 + 32 (A) + 196]
where
COSTPM = Annual cost of maintenance parts and materials, $/yr.
A-12. 9. 6 Total base capital cost.
TBCC = COSTLAND + COSTSDB
where
TBCC = Total base capital cost, $.
310
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A-12.9,7 Total annual operation and maintenance cost.
COSTQM = COSTLB + COSTDSL + COSTPM
where
COSTQM = Total annual operation and maintenance cost, $/yr.
A-12.10 Cost Calculations Output Data
A-12.10.1 Cost of land for sludge drying bed site, COSTLAND, $.
A-12.10.2 Construction cost of sludge drying beds, COSTSDB.
A-12.10.3 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-12.10.4 Annual cost of diesel fuel, COSTDSL, $/yr.
A-12.10.5 Annual cost of maintenance parts and materials, COSTPM, $/yr.
A-12.10.6 Total base capital cost of sludge drying beds, TBCC, $.
A-12.10.7 Total annual operation and maintenance cost of sludge drying
beds, COSTOM, $/yr.
311
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APPENDIX A-13
CHEMICAL CONDITIONING WITH LIME
A-13.1 Background
Conditioning is defined as the pretreatment of sludge to facilitate the
removal of water in subsequent treatment processes. Lime may be added to
sludge to improve the effectiveness of dewatering processes. Lime is often
used in conjunction with other chemicals (e.g., ferric chloride) for condi-
tioning sludge. Note that lime conditioning is not^ equival ent to lime stabi-
lization, a process covered in Appendix A-6. Lime enhances dewatering through
the fl occul ation of calcium carbonate (CaCOo) which provides a granular struc-
ture, thereby increasing sludge porosity ana reducing sludge compressibility.
Two forms of lime are commercially available: (1) quicklime (CaO) and
(2) hydrated lime (Ca(OH)2). Quicklime is less expensive, but must be con-
verted to hydrated lime on site by a process called slaking, in a lime slaking
unit. Hydrated lime can be mixed with water and applied directly. Generally,
larger sewage treatment plants purchase quicklime, and smaller sewage treat-
ment plants use hydrated lime. For a specific plant, a detailed economic
analysis is necessary which takes into account plant size, chemical require-
ments, chemical costs, and labor and maintenance requirements. In this cost
algorithm, the use of hydrated lime is assumed in developing the cost default
values. This assumption should produce adequate cost estimates for small and
medium size plants (those using up to 5 tons of lime/day), but may result in
overestimating O&M costs for larger plants.
The lime chemical conditioning process in this cost algorithm includes
dry lime storage (30 days), a dry lime feeding system (belt gravimetric or
volumetric), a lime-water solution mixing tank, solution feed pump, a building
(or room) to house the equipment, and appurtenant piping and controls. The
base capital cost derived from this algorithm is intended to include the total
chemical feed system. Base annual O&M costs include labor, lime, and parts
and materials. The cost of electrical energy is not included, since it is
insignificant when compared with other O&M costs.
A-13.1.1 Al gorithm Development
The algorithm on the following pages is based, on equations used in the
CAPDET program (1), pages 2.11-10 through 2.11-12, and on other references for
lime conditioning. Information presented in Reference 4, pages 8-6 and 8-7,
Reference 8, pages 15 through 19, and Reference 9, pages 5 through 8, form the
basis for dosage equations. The cost of lime was obtained from chemical sup-
pliers.
312
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Costs and requirements obtained through the use of CAPDET and other
references were fit to equations using a multiple regression program. Capital
costs and O&M requirements are expressed as functions of lime feed capacity.
A-13.2 Input Data
A-13.2.1 Daily sludge volume, SV, gal/day.
A-13.2,2 Sludge suspended sol ids, SS, percent.
A-13.2.3 Sludge specific gravity, SSG, unit! ess.
A-13.2,4 Lime dosage as a fraction of dry sludge solids mass, LD, Ib of
Ca(OH)2/ton of dry sludge solids.
A-13.2.5 Hours per day process is operated, HPD, hr/day.
A-13.2.6 Days per year process is operated, DRY, days/yr.
A-13.3 Design Parameters
A-13,3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-13.3.2 Sludge suspended solids, SS, percent. This input value must be
provided by the user. No default value.
A-13.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is
cal cul ated as fol 1 ows:
SSS «
100-SS (SS)
100 (1.42) (100)
A-13.3.4 Lime dosage as a fraction of dry sludge solids mass, LD, Ib of
Ca(OH)2/ton of dry sludge solids. This input value must be
provided by the user. Lime dosage varies depending on the
sludge characteristics, the use of other conditioning chemi-
cals, and the type of sludge dewatering unit for which the
sludge is being conditioned. The table below provides typical
ranges of lime dosages for several types of sludges.
Pounds of Lime Added Per
Sludge Type Ton of Dry Sludge Solids
Raw Primary Plus Waste 110 to 300
Biological
Digested Primary Plus 160 to 370
Waste Biological
313
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A-13.3.5 Hours per day process is operated, HPD, hr/day. Default value
= 8 hr/day.
A-13.3.6 Days per year process is operated, DPY, days/yr. Default value
= 365 days/yr.
A-13.4 Process Design Calculations
A-13.4.1 Calculate dry solids conditioned per day.
TOSS - (SV) (SS) (SSG) (8.34) (365)
^^ (2,000) (DPY)
where
TDSS = Dry solids conditioned per day, tons/day.
8.34 = Density of water, Ib/gal.
2,000 - Conversion factor, Ib/ton.
A-13.4.2 Calculate the daily lime requirement.
DLR = (LD) (TDSS)
where
DLR = Daily lime requirement, Ib/day.
A-13.4.3 Calculate the design capacity of lime feed system.
i IIP - (DLR) (24)
LUR - (hj£Dj
where
LUR = Design capacity of lime feed system, Ib/day.
A-13.4.4 Calculate the capacity of the liquid diluted lime solution feed
system, LCSF, gal/day. It is assumed that the lime solution
contains 0.5 Ib of Ca(OH)2 per gallon.
where
LCSF * Capacity of the liquid solution feed system, gal/day.
314
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A-13.5 Process Design Output Data
A-13.5.1 Dry solids conditioned per day, TDSS, tons/day.
A-13.5.2 Daily lime requirement, DLR, 1 b/day.
A-13.5.3 Design capacity of lime feed system, LUR, 1b/day.
A-13.5.4 Capacity of diluted lime solution feed system, LCSF, gal/day.
A-13.6 Quantities Calculations
A-13.6.1 Calculate annual labor requirement.
A-13.6.1.1 If LCSF < 90 gal /day, labor is calculated by.
L = 600 + 92.5 (LCSF)0*2827
A-13.6.1.2 If 90 ^ LCSF < 35 gal /day, labor is calculated by:
L = 189.2 (LCSF)0*2565 + 92.5 (LCSF)0-2827
A-13.6.1.3 If 350 _< LCSF < 1,050 gal/day, labor is calculated
by:
L = 33.4 (LCSF)0*5527 + 92.5 (LCSF)0*2827
A-13.6.1.4 If 1,050 <_ LCSF < 10,000 gal/day, labor is
cal cul ated by:
L = 51.8 (LCSF)0*4894 + 92.5 (LCSF)0'2827
A-13.6.1.5 If 10,000 £ LCSF gal/day, labor is calculated by:
L = 12.2 (LCSF)0*647 + 92.5 (LCSF)0-2827
where
L = Annual labor requirement, hr/yr.
A-13.6.2 Electrical energy requirement for this system is insignificant.
315
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A-13.6.3 Annual operation maintenance and material and supply cost
factor. It is assumed that the annual O&M material and supply
cost is 2 percent of the lime system construction cost.
OMMP = 0.02
where
OMMP = O&M material and supply cost factor expressed as a fraction of the
lime system construction cost.
A-13.7 Quantities Calculations Output Data
A-13.7.1 Annual labor requirement, L, hr/yr.
A-13.7.2 O&M material and supply cost factor, OMMP, expressed as a frac-
tion of the lime system capital cost.
A-13.8 Unit Price Input Required
A-13.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-13.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-13.8.3 Cost of lime, LMCST, $/l b. Default value = $0.05/lb
(ENRCCI/4,006).
A-13.8.4 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-13.9 Cost Calculations
A-13.9.1 Capital cost of lime storage and feed system.
A-13.9.1.1 If LUR < 750 Ib/day, lime system cost is calculated
by:
CCLIME = (30,000)
A-13.9.1.2 If LUR >_ 750 Ib/day, lime system cost is calculated
by:
CCLIME = (376) (LUR)0'6614
where
CCLIME = Capital cost of lime storage and feed system, $.
316
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A-13.9.2 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-13.9.3 Annual cost of lime.
COSTLM = (DLR) (365) (LMCST)
where
COSTLM = Annual cost of lime, $/yr.
A-13.9.4 Annual maintenance parts and material cost.
COSTMP = (OMMP) (CCLIME)
where
COSTMP = Annual material and supply cost, $/yr.
A-13.9.5 Total base capital cost.
;TBCC = CCLIME
where
TBCC = Total base capital cost, $.
A-13.9.6 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTLM + COSTMP
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-13.10 Cost Calculations Output Data
A-13.10.1 Capital cost of lime storage and feed system, CCLIME, $.
317
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A-13.10.2 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-13.10.3 Annual cost of 1 ime, COSTLM, $/yr.
A-13.10.4 Annual maintenance parts and material cost, COSTMP, $/yr.
A-13.10.5 Total base capital cost of lime conditioning, TBCC, $.
A-13.10.6 Total annual operation and maintenance cost of lime condition-
ing, COSTOM, $/yr.
318
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APPENDIX A-14
CHEMICAL CONDITIONING WITH FERRIC CHLORIDE
A-14.1 Background
Ferric chloride may be added to sludge to improve the effectiveness of
dewatering and thickening. Ferric chloride may be used alone or in conjunc-
tion with lime. Ferric chloride enhances the dewaterabil ity of sludges
through the precipitation of ferric hydroxide which enhances floe formation.
In addition, the ferric hydroxide neutralizes negatively charged solids, which
decreases hydrostatic repulsion and causes aggregation.
Ferric chloride is available in liquid (35 to 45 percent Fed 3) or dry
(crystals) forms. Liquid ferric chloride is a corrosive dark brown oily
appearing solution with a weight of 11.2 to 12.4 Ib/gal. Liquid form iron
salts can be shipped in 3,000- to 4,000-gal bulk truckload lots, in 4,000- to
10,000-gal bulk carload lots, and 5- to 13-gal carboys. Storage tanks must be
lined with corrosion-resistant material.
Dry ferric chloride is available in 18- to 40-gal steel drums. Once the
drums are opened, the contents should be mixed with water and stored in solu-
tion. Heat-resistant mixing tanks must be used due to the heat generated when
ferric chloride is mixed with water.
A typical ferric chloride feed system includes a storage tank for the
liquid ferric chloride (e.g., 30-day storage), a mixing tank to accurately
combine ferric chloride and water, a metering pump to add accurate dosages of
ferric chloride to the sludge flow, a building (or room) to house equipment,
and appurtenant piping and controls. The base capital cost derived from this
algorithm is intended to include the total chemical feed system. Base annual
O&M costs include labor, lime, and replacement parts and materials.
A-14.1.1 Algorithm Devel opment
The algorithm on the following pages is based on equations used in the
CAPDET program (1), pages 2.11-7 through 2.11-9, and from information obtained
from Reference 4, pages 8-6 and 8-7; and Reference 8, pages 15 through 19.
The cost of ferric chloride was quoted by chemical suppliers.
Capital costs and O&M requirements were fit to equations using a multiple
regression program. Equations were developed as functions of the chemical
feed capacity.
319
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A-14.2 Input Data
A-14.2.1 Daily sludge volume, SV, gal/day.
A-14.2.2 Sludge suspended solids, SS, percent.
A-14.2.3 Sludge specific gravity, SSG, unitless.
A-14.2.4 Hours per day process is operated, HPD, hr/day.
A-14.2.5 Days per year process is operated, DRY, days/yr.
A-14.2.6 Ferric chloride dosage as a fraction of dry sludge solids mass,
FCD, 1 b of FeClg/tons of dry sludge solids.
A-14.3 Design Parameters
A-14.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-14.3.2 Sludge suspended solids, SS, percent. This input value must be
provided by the user. No default value.
A-14.3.3 Sludge specific gravity, SSG, unitless. Default value is cal-
culated by the following equation:
SSG = 100-SS (SS)
100 (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
A-14.3.4 Hours per day process is operated, HPD, hr/day. Default value
= 8 hr/day.
A-14.3.5 Days per year process is operated, DPY, days/yr. Default value
= 365 days/yr.
A-14.3.6 Ferric chloride dosage as a fraction of dry sludge solids mass,
FCD, Ib of FeC^/ton of dry sludge solids. This input value
must be provided by the user. No default value. Ferric chlo-
ride dosages vary depending on 'the sludge characteristics, the
use of other chemical conditioning chemicals, and the type of
sludge dewatering or thickening unit for which the sludge is
being conditioned. Dosages are usually obtained through exten-
sive laboratory and/or pilot plant testing. The table below
provides typical ranges of ferric chloride dosages for several
types of si udges.
320
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Pounds of Ferric Chloride
SI udge Type Added Per Ton of Dry Sludge Solids
Raw Primary 40 to 120
Waste Activated 120 to 200
Anaerobically Digested, 60 to 200
Combined
A-14.4 process Design Calculations
A-14.4.1 Calculate dry solids conditioned per day.
. .
(2,000) (100) (DRY)
where
TDSS = Dry solids conditioned per day, tons/day.
8.34 = Density of water, Ib/gal.
2,000 = Conversion factor, Ib/ton.
A-14.4.2 Calculate the daily ferric chloride requirement.
DFCR = (FCD) (TDSS)
where
DFCR - Daily ferric chloride requirement, Ib/day.
A-14.4.3 Calculate system design capacity expressed as equivalent iron
molecules, accounting for hours per day the system is operated.
TSI1R - (DFCR) (55.8) (24)
ISUR -- (162) (HPD)
where
ISUR = System design capacity, Ib iron/day.
55.8 = Molecular weight of iron, g/mole.
162 = Molecular weight of ferric chloride, g/mole.
A-14.4.4 Calculate the capacity of the liquid chemical solution feed
system. It is assumed that liquid Fed 3 contains 4.11 Ib of
iron per gallon,
LCSF «
Ltbi-
321
-------
where
LCSF = Capacity of the liquid chemical solution feed system, gal/day.
A-14.5 Process Design Output Data
A-14.5.1 Dry solids conditioned per day, TOSS, tons/day.
A-14.5.2 Sludge specific gravity, SSG, unitless.
A-14.5.3 Daily ferric chloride requirement, DFCR, 1 b/day.
A-14.5.4 System design capacity, ISUR, Ib iron/day.
A-14.5.5 Design capacity of the ferric chloride feed system, LCSF,
gal/day.
A-14.6 Quantities Cal cul ations
A-14.6.1 Calculate annual operation and maintenance labor requireTient.
A-14.6.1.1 If LCSF < 90 gal/day, labor requirement is:
L = 600
A-14.6.1.2 If 90 <_ LCSF < 350 gal/day, labor requirement is
cal cul a ted by:
L = 189.2 (LCSF)0'2565
A-14.6.1.3 If 350 £ LCSF < 1,050 gal/day, labor requiranent is
calculated by:
L = 33.4 (LCSF)0-5527
A-14.6.1.4 If 1,050 _>. LCSF <_ 10,000 gal/day, labor requirement
is calculated by:
L = 51.8 (LCSF)
0.4894
A-14.6.1.5 If LCSF 2.10,000 gal/day, labor requirement is cal
culated by:
L = 12.2 (LCSF)0-647
322
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where
L = Annual operation and maintenance labor requirement, hr/yr.
A-14.6.2 Electrical energy requirement for this system is insignificant.
A-l4.6.3 Calculate operation and maintenance material supply cost fac-
tor. This cost factor is expressed as a percentage of the fer-
ric chloride system capital cost.
' OMMP = 0.02
where
OMMP = O&M material and supply cost factor expressed as a fraction of the
ferric chloride system capital cost.
A-l4.7 Quantities Calculations Output Data
A-l4.7.1 Annual labor requirement, L» hr/yr.
A-14.7.2 Annual O&M material and supply cost factor, OMMP, fraction of
system capital cost.
A-l4.8 Unit Price Input Required
A-l4.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-l4.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-l 4.8.3 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-14.8.4 Cost of ferric chloride, FCCST, $/l b. Default value = 0.475
$/lb (ENRCCI/4,006).
A-14.9 Cost Calculations
A-l4.9.1 Capital cost of iron salt storage and feed system.
A-14.9,1.1 If ISUR < 1,000 Ib/day, ferric chloride system cost
is cal culated by:
CCFC = (67,850)
323
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A-14.9.1.2 If 1,000 _< ISUR < 4,000 Ib/day, ferric chloride
cost is calculated by:
CCFC = (3,855) (ISUR)0'4152
A-14.9. 1.3 If 4,000 <_ ISUR < 10,000 Ib/day, ferric chloride
system cost is calculated by:
CCFC = (100) (ISUR)0'8857
A-14.9, 1.4 If ISUR _>. 10,000 Ib/day, ferric chloride system
cost is calculated by:
CCFC = (0.458) (ISUR)1'425
where
CCFC - Capital cost of ferric chloride feed system, $.
A-14.9. 2 Annual cost of ferric chloride.
COSTFC - (DFCR) (DRY) (FCSST)
where
COSTFC = Annual cost of ferric chloride, $/yr.
A-14.9.3 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual operation and maintenance labor cost, $/yr.
A-14.9. 4 Annual maintenance parts and material cost.
COSTMP = (OMMP) (CCFC)
where
COSTMP » Annual maintenance parts and material cost, $/yr.
324
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A-14.9. 5 Total base capital cost.
TBCC = CCFC
where
TBCC = Total base capital cost, $.
A-14.9.6 Total annual operation and maintenance cost.
COSTOM = COSTFC + COSTLB + COSTMP
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-14.10 Cost Calculations Output Data
A-14.10.1 Capital cost of iron salt storage and feed system, CCFC, $.
A-14.10.2 Annual cost of ferric chloride, COSTFC.
A-14.10.3 Annual operation and maintenance labor cost, COSTLB, $/yr.
A-14.10.4 Annual maintenance parts and material cost, COSTMP, $/yr.
A-14.10.5 Total base capital cost, TBCC, $.
A-14.10.6 Total annual operation and maintenance cost, COSTOM, $/yr.
325
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APPENDIX A-15
CHEMICAL CONDITIONING WITH POLYMERS
A-15.1 Background
Polymers may be added to sludge to Improve the effectiveness of dewater-
ing units and thickening units. Polymers may be used alone or in conjunction
with other conditioning chemicals (e.g., ferric chloride). Polymers enhance
particle destabil ization through interparticle bridging, charge neutraliza-
tion, and dehydration.
There are many types of polymers available for sludge conditioning. It
is common to experiment with different types and dosages to determine the most
cost-effective polymer for a specific sludge conditioning requirement.
The polymer feed system in this algorithm includes a storage tank for the
polymer (e.g., 30-day storage), a mixing tank to accurately combine polymer
and water, a metering pump which is controlled by sludge volume to add accu-
rate dosages of polymer to the sludge flow, a building (or room) to house
equipment, and appurtenant piping and controls. The capital cost derived from
this algorithm is intended to include the total chemical feed system. O&M
costs include the purchase of polymer, labor, and maintenance parts and mate-
rials. Due to their relative low costs compared with other O&M components,
electrical energy costs are not included.
A-15.1.1 Algorithm Development
The algorithm on the following pages is based on values obtained using
the CAPDET program (1), pages 2.11-13 through 2.11-15. Polymer dosage re-
quirement equations are based on information presented in Reference 4, page 8-
21, and Reference 8, pages 15 through 19. An average polymer cost for sludge
conditioning was provided by chemical suppliers.
Costs and requirements obtained from CAPDET and other references were fit
to equations using a multiple regression program. Capital costs and O&M
requirements are based on polymer feed capacity.
A-15.2 Input Data
A-15.2.1 Daily sludge volume, SV, gal/day.
A-15.2.2 Sludge suspended solids, SS, percent.
A-15.2.3 Sludge specific gravity, SS6, unit! ess.
326
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A-15.2.4 Polymer dosage as a fraction of dry sludge solids mass, PD, Ib
of polymer/ton of dry sludge solids.
A-15.2.5 Hours per day process is operated, HPD, hr/day.
A-15.2.6 Days per year process is operated, DPY, days/yr.
A-15.3 Design Parameters
A-15.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-15.3.2 Sludge suspended solids, SS, percent. This input value must be
provided by the user. No default value.
A-15.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is cal-
cul ated as foil ows:
SSG =
100-SS (SS)
100 (1.42) ]
(1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Assumed sludge solids specific gravity.
A-15.3.4 Polymer dosage as a fraction of dry sludge solids mass, PD, Ib
of polymer/ton of dry sludge solids. This input value must be
provided by the user. Polymer dosages vary depending on the
sludge characteristics, the use of other chemical conditioning
chemicals, and the type of sludge dewatering or thickening unit
for which the sludge is being conditioned. The table below
provides typical ranges of polymer dosages for several types of
si udges.
Pounds of Polymer Added
SI udge Type Per Ton of Dry Sludge Solids
Raw Primary 0.5 to 1.0
Waste Activated 8 to 15
Anaerobically Digested, 5 to 12
Combined
A-15.3.5 Hours per day process is operated, HPD, hr/day. Default value
= 8 hr/day.
A-15.3.6 Days per year process is operated, DPY, days/yr. Default value
= 365 days/yr.
327
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A-15.4 Process Design Calculations
The costing for this process is parametric and determined by the daily
polymer requirement.
A-15.4.1 Calculate dry solids conditioned per day.
TIKS - (SV) (SS) (SSG) (8.34) (365)
(100) (2,000) (DPY)
where
TDSS - Dry solids conditioned per day, tons/day.
8.34 = Density of water, Ib/gal.
2,000 = Conversion factor, Ib/ton.
A-15.4.2 Calculate the daily polymer requirement.
DPR = (PD) (TDSS)
where
DPR = Daily polymer requirement, Ib/day.
A-15.4,3 Calculate the design capacity of the polymer feed system.
PUR =1DP|)J24I
(HPU)
where
PUR = Design capacity of polymer feed system, Ib/day.
A-15.4.4 Calculate the capacity of the liquid diluted polymer solution
feed system. It is assumed that the solution of polymer has a
concentration of 0.25 percent polymer.
irsf - (PUR) (100)
LU5r " (6.2b) (8.34)
where
LCSF = Capacity of the liquid solution feed system, gal/day.
8.34 = Density of water, Ib/gal.
A-15.5 Process Design Output Data
A-15.5.1 Dry solids conditioned per day, TDSS, tons/day.
A-15.5.2 Daily polymer requirement, DPR, Ib/day.
328
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A-15.5.3 Design capacity of polymer feed system, PUR, 1 b/day.
A-15.5.4 Capacity of the diluted polymer solution feed system, LCSF,
gal/day.
A-15.6 Quantities Calculations
A-15.6,1 Annual operation and maintenance labor requirement.
A-15.6.1.1 If LCSF < 1,000 gal/day, annual labor is calculated
by:
L = 16.7 (LCSF)0-4894 + 46.3 (LCSF)0-2827
A-15.6.1.2 If 1,000 _< LCSF < 10,000 gal/day, annual labor is
cal cul a ted by:
L » 25.9 (LCSF)0-4894 + 46.3 (LCSF)0-2827
A-15.6.1.3 If LCSF _>. 10,000 gal/day, annual labor is cal cu-
1 ated by:
L = 6.1 (LCSF)0-647 + 46.3 (LCSF)0-2827
where
L = Annual operation and maintenance labor requirement, hr/yr.
A-15.6.2 Electrical energy requirement for this system is insignificant.
A-15.6.3 Annual operation and maintenance material supply cost factor.
It is assumed that the annual O&M material and supply cost is 2
percent of the polymer system construction cost.
OMMP = 0.02
where
OMMP = O&M material and supply cost factor, fraction of the polymer
system construction cost,
A-15.7 Quantities Calculations Output Data
A-15.7.1 Annual operation and maintenance labor requirement, L, hr/yr.
329
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A-15.7.2 Annual O&M parts and materials cost factor, OMMP, fraction of
polymer system construction cost.
A-15.8 Unit Price Input Required
A-15.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-15.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-15.8.3 Cost of labor, COSTL, $/hr. Default value = $13,,OQ/hr
(ENRCCI/4,006).
A-15.8.4 Cost of polymer, PCST, $/l b. Default value = 2.80, $/l b
(ENRCCI/4,006).
A-15.9 Cost Calculations
A-15.9.1 Capital cost of polymer storage and feed system.
A-15.9.1.1 If PUR < 375 1 b/day, the polymer system cost is
calcul a ted by:
CCP - 27,600 + 235 (PUR)0'95
751
A-15.9.1.2 If PUR >_ 375 1 b/day, the polymer system cost is
cal culated by:
CCP = 57,500 -»- 235 (PUR)0'90
where
CCP = Capital cost of polymer system, $.
A-15.9.2 Annual cost of operation and maintenance labor.
COSTLB - (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-15.9.3 Annual cost of polymer.
COST? = (DPR) (DPY) (PCST)
330
-------
where
COSTP = Annual cost of ferric chloride, $/yr.
A-15.9.4 Annual maintenance parts and material cost.
CQSTMP = (OMMP) (CCP)
where
COSTMP = Annual maintenance parts and material cost, $/yr.
A-15.9.5 Total base capital cost.
TBCC - CCP
where
TBCC = Total base capital cost, $.
A-15.9.6 Total annual operation and maintenance cost.
COSTOM « COSTLB + COSTP + COSTMP
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-15.10 Cost Calculations Output Data
A-l5.10.1 Capital cost of polymer system, CCP, $..
A-15.10.2 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-15.10.3 Annual cost of polymer, COSTP, $/yr.
A-15.10.4 Annual material and supply cost, COSTMP, $/yr.
A-15.10.5 Total base capital cost of polymer conditioning, TBCC, $.
A-15.10.6 Total annual operation and maintenance cost of polymer eondi'
tioning, COSTOM, $/yr.
331
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APPENDIX A-16
FLUIDIZED BED INCINERATION
A-16.1 Background
Fluidized bed incinerators utilize a fluidized bed of sand as a heat
reservoir to promote uniform combustion of sludge. Air is injected into the
bottom of the incinerator at a pressure of 3 to 5 psig to fluidize the bed.
The bed temperature is controlled at approximately 1,200 to 1,400 °F using gas
or fuel oil, as necessary. Combustion is controlled by varying the sludge
feed and/or the air flow to the reactor vessel to completely oxidize all
organic matter in the sludge.
Dewatered sludge is injected either above or directly into the fluidized
sand bed. Solids remain in the sand bed until the particles are reduced to
mineral ash. Ash is carried out of the top of the furnace by the upflowing
exhaust gases where it is removed by air pollution control devices. Venturi
scrubbers, electrostatic precipitators, and cyclones have been used to control
pollutants from incinerators, as' specified by federal, state, or local re-
qui rements.
Fluidized bed furnaces are reliable due to the presence of few mechanical
components compared with other incineration devices. In addition, minimal
pollutant emissions are produced under proper operating conditions. However,
the process is complex and requires the use of trained personnel to maintain
efficient operation. Since capital and O&M costs are relatively high, fluid-
ized bed incinerators are typically limited to larger treatment plants and at
locations where land disposal of sludges is limited or prohibited.
Fluidized bed incinerators are purchased as package units from manufac-
turers in standard sizes which begin at 6 ft in diameter and increase in 1-ft
increments up to 25 ft. Size is based on numerous factors, including:
Solids loading rate.
Percent solids in sludge.
Percent volatile solids.
Sludge heat value.
Hours per week of operation.
Base capital costs obtained with the following algorithm include purchase
and installation of the incinerator, installation of controls and other ancil-
lary equipment, and construction of a building to house the incinerator. Base
capital costs do not include pollution control devices, since this cost de-
pends upon the degree of control required. Pollution control can add between
10 and 25 percent to the base capital cost, depending on the equipment used.
Heat recovery devices are not included in the costs.
332
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Base annual O&M costs include labor, electrical energy, auxiliary and
startup fuel, and replacement parts and materials.
A-16.1.1 Algorithm Development
The following algorithm is based on costs and requirements obtained by
accessing the CAPDET program. Equations used in the CAPDET program are on
pages 2.29-5 through 2.29-20 of Reference 1. Costs and requirements were
obtained by varying sludge volume and solids concentration entering the incin-
erator, using the following input parameters:
Operation hours per day = 24 hr/day.
Operation days per year = 360 days/yr.
Heat value of sludge = 118 Btu/lb.
Sludge percent volatile solids = 70 percent.
Ambient air temperature = 40 °F.
Operating temperature - 1,100 °F.
Detention time = 15 seconds.
Sand-to-sludge ratio = 6 Ib/lb.
Specific weight of sand = 110 Ib/ft^.
Cost of standard 15-ft-diameter incinerator = $1,680,000.
Additional input parameters (projected 1983 values) shown on Table 1-1
were obtained from construction cost guides (2, 3). Cost of the standard
incinerator was obtained from equipment suppliers.
Fuel requirements obtained from CAPDET were determined to be too high;
therefore, they were estimated using methods described in Reference 4.
Costs and requirements obtained through use of the CAPDET program or
other references were fit to an equation using a multiple regression program.
Other equations were used directly as they appear in CAPDET.
A-16.2 Input Data
A-16.2.1 Daily sludge volume, SV, gal/day.
A-16.2.2 Feed sludge suspended solids concentration, SS, percent.
A-16.2.3 Sludge specific gravity, SSG, unitless.
A-16.2.4 Volatile suspended solids concentration, VSS, percent.
A-16.2.5 Hours per day process is operated, HPD, hr/day.
A-16.2.6 Days per year process is operated, DPY, days/yr.
A-16.3 Design Parameters
A-16.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-16.3.2 Feed sludge suspended solids concentration, SS, percent. This
input value must be provided by the user. No default value.
333
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A-16.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not available, default value is cal-
culated using the following equation:
SSG = ioo - ss . (ss) —
100 (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Specific gravity of sludge solids, unitless.
A-16.3.4 Volatile suspended solids concentration, VSS, percent. Default
value = 60 percent.
A-16.3.5 Hours per day process is operated, HPD, hr/day. Default value
= 24 hr/day.
A-16.3.6 Days per year process is operated, DPY, days/yr. Default value
= 360 days/yr.
A-16.4 Process Design Calculations
A-16.4.1 Calculate loading rate of dry sludge solids in Ib/hr.
IB = (SV) (365) (8.34) (SS) (SGS)
LK (DPY) (HPD) (100)
where
LR = Loading rate of dry sludge solids, Ib/hr.
8.34 = Density of water, Ib/gal.
A-16.4. 2 Calculate heating value of the sludge solids.
HV - j LR) (VSS) (10.000)
"(TOO)
where
HV = Heating value of the sludge, Btu/hr.
10,000 = Assumed Btu per Ib of volatile solids in the sludge. This value
is approximately correct for raw wastewater solids. Reduce Btu
per Ib by approximately 25 percent if sludge is chemically con-
ditioned with lime or ferric chloride.
A-16.4. 3 Calculate moisture content of sludge.
M = (100) - (SS)
334
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where
M = Moisture content of sludge, percent.
A -16. 4.4 Calculate si udge 1 oadi ng rate.
SL = 10(2'7 ' °'
where
SL = Sludge loading rate, 1 b/ft2/hr.
A-16.4. 5 Calculate cross-sectional area of incinerator.
A-J£
* SL
where
A = Cross-sectional area of incinerator, ft2.
A-16.4.6 Compute annual auxiliary fuel supply requirement.
A-16.4. 6.1 Calculate burning rate.
BR = 10(5.947 - 0.0096M)
where
BR = Burning rate, Btu/ft2/hr.
A-16.4. 6. 2 Calculate total heat input rate.
HIR = (BR) (A)
where
HIR = Total heat input rate, Btu/hr.
A-16.4. 6. 3 Calculate auxiliary fuel supply required,
AFS = (HIR) - (HV)
335
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where
AFS = Auxiliary fuel supply required, Btu/hr.
A-16.4.6.4 Calculate fuel oil required annually.
Fn - (AFS) (DRY) (HPD) (1.1)
ru (144,000)
where
FO = Annual fuel oil required, gal/yr.
1.1 = Efficiency factor, unitless.
144,000 = Btu in 1 gal of fuel oil , Btu/gal.
A-16.5 Process Design Output Data
A-16.5.1 Loading rate of dry sludge solids, LR, 1 b/hr.
A-16.5.2 Heating value of sludge solids, HV, Btu/hr.
A-16.5.3 Moisture content of sludge, M, percent.
A-16.5.4 Sludge loading rate, SL, 1 b/ft2/hr.
A-16.5.5 Cross-sectional area of incinerator, A, ft .
A-16.5.6 Annual auxiliary fuel oil requirement, FO, gal/yr.
A-16.6 Quantities Cal cul ations
A-16.6.1 Determine size and number of incinerators to be used. Gener-
ally, the size of commercial fluidized bed incinerators begins
at 6 ft in diameter, and increases in 1-ft increments to the
largest diameter of 25 ft.
A-16.6.1.1 Calculate incinerator diameter if only one inciner-
ator is used.
D = (1.273 A)0'5
where
D = Incinerator diameter, ft.
1.273 = 4/3.1416.
If incinerator diameter, D, is equal to or less than 25 ft, use
one incinerator and increase D to the next larger integer
greater than 5 and less than 26. Note that this does not
include standby capacity.
336
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A-16.6.1.2 Calculate diameters of multiple incinerators if
diameter, D, of one incinerator is more than 25 ft.
D = [(1.273) (A/N)]0'5
where
D = Diameter of incinerator, ft.
1.273 = 4/3.1416.
A = Area of incinerator, ft2.
N = Number of incinerators.
Try N = 2 first. If A/N is greater than 490 ft2, then try suc-
cessive integer values of N (i.e., 3, 4, etc.) until the ratio
of A/N is less than 490 ft^. Note that this does not include
standby capacity.
A-16.6.2 Calculate area of incinerator building.
AB = (1,700 + 90 D) (N)
where
AB = Area of incinerator building, ft2.
A-16.6.3 Calculate annual maintenance labor requirement.
ML = (6) [(LR) (HPD)]0'58
where
ML = Annual maintenance labor requirement, hr/yr.
A-16.6.4 Calculate annual operation labor requirement.
OL = (18) [(LR) (HPD)]0-54
where
OL = Annual operational labor requirement, hr/yr.
A-16.6.5 Calculate annual electrical energy requirement.
E = (N) (0.88) (DRY) (HPD) (1.165) [D]1'9
337
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where
E = Annual electrical energy requirement, kWhr/yr.
0.88 = Conversion factor, hp to kWhr.
A-16.6.6 Annual operation and maintenance parts and material cost is
expressed as a percentage of the total base capital cost of the
incinerator (TBCC) to be calculated later.
OMMP = 0.45 percent
where
OMMP » Annual O&M parts and materials cost factor, percent of base
capital cost.
A-16,7 Quantities Calculations Output Data
A-16.7.1 Diameter of incinerators, D, ft.
A-16.7.2 Number of incinerators, N.
y
A-16.7.3 Area of incinerator building, AB, ft .
A-16.7.4 Annual maintenance labor requirement, ML, hr/yr.
A-16.7.5 Annual operational labor requirement, OL, hr/yr.
A-16.7.6 Annual electrical energy requirement, E, kWhr/yr.
A-16.7.7 Annual OSM parts and materials cost factor, OMMP, fraction of
base capital cost.
A-16.8 Unit Price Input Required
A-16.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-16.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-16.8.3 Cost of operational labor, COSTL, $/hr. Default value =
$13.00/hr (ENRCCI/4,006).
A-16.8.4 Cost of fuel oil, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-16.8.5 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
338
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A-16.9 Cost Calculations
A-16. 9. 1 Cost of installed incinerator and appurtenances.
A-16.9. 1.1 Calculate the cost of a "standard size" fluidized
bed incinerator of 15-ft diameter.
COSTFI = $1,680,000
.where
COSTFI = Cost of "standard size" 15-ft-diameter fluidized bed
incinerator, $.
A-16.9. 1.2 Calculate the cost of installed incinerator and
appurtenances
COSTFB = (0.122) (o)°*7788 (N)0'9 (COSTFI)
where
COSTFB = Cost of installed fluidized bed incinerator, $.
A-16.9. 2 Cost of incinerator building and foundation.
COSTIB * (AB) (145)
where
COSTIB = Cost of incinerator building and foundation, $.
145 = Last quarter 1983;cost for building, $/ft-.
A-16.9. 3 Annual cost of operation and maintenance labor.
COSTLB • C(OL) + (ML)] (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-16.9. 4 Annual cost of fuel oil.
COSTDSL = (FO) (COSTDF)
339
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where
COSTDSL = Annual cost of fuel oil , $/yr.
A-16.9.5 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-16.9.6 Total base capital cost of fluid!zed bed incinerator.
TBCC = (COSTFB) + (COSTIB)
where
TBCC = Base capital cost of fluidized bed incinerator, $.
A-16.9.7 Annual cost of maintenance parts and materials.
COSTMP = (TBCC) (0.0045)
where
COSTMP = Annual cost of operation and maintenance materials, $/yr.
A-16.9.8 Total annual operation and maintenance cost.
COSTOM = (COSTLB) + (COSTDSL) + (COSTEL) + (COSTMP)
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-16.10 Cost Calculations Output Data
A-16.10.1 Cost of installed incinerator and appurtenances, COSTFB, $.
A-16.10.2 Cost of incinerator building and foundation, COSTIB, $.
A-16.10.3 Annual cost of operational labor, COSTLB, $/yr.
A-16.10.4 Annual cost of fuel oil, COSTDSL, $/yr.
340
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A-16.10.5 Annual cost of electrical energy, COSTEL, $/yr.
A-16.10.6 Annual cost of maintenance parts and materials, COSTMP, $/yr.
A-16.10.7 Total base capital cost of fluidized bed incinerator facility,
TBCC, $.
A-16.10.8 Total annual cost of operation and maintenance for fluidized
bed incinerator, COSTOM, $/yr.
341
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APPENDIX A-17
MULTIPLE HEARTH INCINERATION
A-17.1 Background
Multiple hearth incinerators are mul ti-chambered vertically mounted fur-
naces with hearths located above one another. Within each hearth is a set of
rabble arms used to move the sludge in a spiral pattern around each hearth.
Dewatered sludge is fed into the top of the incinerator and is swept radially
towards the center, where the sludge drops to the second hearth. The sludge
is again swept spirally to the periphery of the hearth, and passes downward to
the next hearth. This pattern is continued through subsequent hearths. As
the sludge moves toward the bottom, further oxidation occurs, yielding an ash
which is removed from the bottom. Hot rising gases flow in a direction
counter-current to the si udge fl ow.
Multiple hearth incineration is a two-stage process consisting of sludge
drying on the upper hearths and combustion of volatile solids on the lower
hearths. The process reduces dewatered sludge solids (greater than 15 percent
solids) to an inert ash that is readily disposed. Auxiliary fuel is usually
required for feed sludge concentrations between 15 and 30 percent solids.
Feed solids greater than 50 percent solids (excluding conditioning chemicals)
are typically not incinerated, since temperatures in excess of the refractory
material and metallurgical limits of the furnace may be achieved.
Base capital costs in the following algorithm include purchase of the
incinerator and ancillary equipment from the manufacturer, installation of all
equipment, and construction of a building to house the incinerator. Base
annual O&M costs include labor, electrical energy, auxiliary fuel, and re-
placement parts and materials.
A-17.1.1 Algorithm Development
The following algorithm was developed using information provided in Pro-
cess Design Manual for Sludge Treatment and Pisposal (4). Calculations used
in determining fuel requirements for sludge incineration were obtained from
pages 11-10 through 11-20 of this manual. Process design equations follow
from the descriptions on pages 11-31 through 11-48 of Reference 4. Additional
cost information used for base capital and O&M costs was obtained from Refer-
ence 7, pages A-186 and A-187, and Reference 8, pages 315 through 331. Costs
and requirements were fit to equations using a multiple regression program.
A-17.2 Input Data
A-17.2.1 Daily sludge volume, SV, gal/day.
342
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A-17.2.2 Feed sludge suspended solids concentration, SS, percent.
A -17. 2. 3 Sludge specific gravity, SSG, unit! ess.
A-17. 2. 4 Volatile suspended solids concentration, VSS, percent.
A-17.2. 5 Hours per day process is operated, HPD, hr/day.
A-17. 2. 6 Days per year process is operated, DPY, days/yr.
A-17. 3 Design Parameters
A-17. 3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-17. 3.2 Feed sludge suspended solids concentration, SS, percent. This
input value must be provided by the user. No default value.
A-17. 3.3 Sludge specific gravity., SSG, unitless. This value should be
provided by the user. If not available, default value is cal-
culated using the following equation:
100-SS (SS)
100 (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Specific gravity of si udge solids, unitless.
A-17.3.4 Volatile suspended solids concentration, VSS, percent. Default
value = 60 percent.
A-17.3.5 Hours per day process is operated, HPD, hr/day. Default value
= 24 hr/day.
A-17.3.6 Days per year process is operated, DPY, days/yr. Default value
- 360 days/yr.
A-17.4 Process Design Calculations
A-17.4.1 Calculate loading rate of dry sludge solids in 1 b/hr.
'IP- (SV) (365) (8.34) (SS) (SSG)
LK - (DPY) (HPD) (100)
where
LR = Loading rate of dry sludge solids, 1 b/hr.
343
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A-17.5 Process Design Output Data
A -17, 5. 1 Loading rate of dry sludge solids, LR, Ib/day.
A-17.6 Quantities Cal cul ations
A-17.6. 1 Calculate annual operation and maintenance labor requirement.
L = [- 9.886 x 10"11 (SV)3 + 1.28 x 10"6 (SV)2 + 0.38 (SV) + 1,708]
where
L = Annual operation and maintenance labor requirement, hr/yr.
A-17.6.2 Calculate annual fuel oil requirement. The supplementary fuel
oil (or natural gas) required for incinerator start-up and
incineration is highly sensitive to the moisture content of the
sludge and the Btu value of the sludge solids. It is therefore
very difficult in a general cost algorithm to provide a simple
formula for supplementary fuel oil requirements. Self-con-
tained combustion without supplementary fuel is often possible
with raw primary sludges which have been dewatered to a solids
concentration of over 30 percent. Whenever possible, the sup-
plementary fuel oil requirement used in the algorithm should be
obtained through engineering mass balance calculations for
site-specific conditions. The calculations shown in Subsec-
tions A-17.6. 2.1 through A-17.6. 2. 9 provide a reasonable
approximation based on an incinerator temperature of 1,400 °F
and ambient a.ir and sludge temperature of 60 °F.
A-17.6. 2.1 Calculate heating value of the sludge.
_ (LR) (VSS) (10,000)
-_
where
HV = Heating value of the sludge, Btu/hr.
10,000 = Assumed Btu per Ib of volatile solids in the sludge.
This value is approximately correct for raw wastewater
solids. Reduce Btu per Ib by approximately 25 percent
if sludge is chemically conditioned with lime or
ferric chloride.
A-17.6.2. 2 Calculate combustion air requirement.
- (HV) (7.5) (2)
(10,000)
344
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where
AIR = Combustion air requirement in Ib of dry air/hr.
7.5/10,000 = Assumed Ib of dry air required per 10,000 Btu.
2 = Excess air factor, unitless.
A-17.6.2.3 Calculate heat required to raise ambient air tem-
perature (60 °F) to furnace temperature of 1,400 °F.
HAIR - (AIR) (1,340) [(0.256) + (0.013) (0.5)]
where
HAIR = Heat required to raise ambient air temperature to
1,400 °F, Btu/hr.
1,340 = Assumed difference between furnace temperature of
1,400 °F and ambient air temperature of 60 °F.
0.256 - Btu required to heat 1 Ib of air in Btu/lb - °F.
0.0131 - Assumed water content of ambient air in Ib water/1b
air.
0.5 - Btu required to heat water in Btu/lb - °F.
A-17.6.2.4 Calculate heat required to raise sludge dry solids
temperature to furnace temperature of 1,400 °F.
HSS = (LR) (0.25) (1,340)
where
HSS = Heat required to raise sludge solids temperature to
1,400 °F, Btu/hr.
0.25 = Btu required to heat 1 Ib of solids in Btu/lb - °F.
1,340 = Assumed difference between furnace temperature of 1,400
•°F and sludge temperature of 60 °F.
A-17.6.2.5 Calculate heat required to raise temperature of
water (moisture content) of feed sludge.
HW
= [
(SV)
345
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where
HW = Heat required to raise sludge moisture content from 60
°F to 212 °F» evaporate water, and raise temperature of
water vapor to 1,400 °F, in Btu/hr.
8.34 = Density of water, Ib/gal.
1,716 = Btu required to raise 1 Ib of water from 60 °F to a
water vapor temperature of 1,400 °F, Btu/lb.
A-17.6.2.6 Calculate heat required to raise temperature of
water formed during combustion reaction to 1,400 °F.
HCW = 0.0782 (HAIR + HSS + HW)
where
HCW = Heat required to raise temperature of water formed
during combustion reaction to 1,400 °F, Btu/hr,
0.0782 = Conversion factor.
A-17.6.2.7 Calculate heat required to compensate for radiation
losses. Assume 5 percent radiation losses.
HL = (0.05) (HAIR + HSS + HW + HCW)
where
HL = Heat required to compensate for radiation losses,
Btu/hr.
0.05 = Assumed radiation heat loss, fraction of total,
A-17.6.2.8 Calculate supplemental heat required by inciner-
ator.
SH = (HAIR + HSS + HW + HCW + HL) - (HV)
where
SH = Supplemental heat required by incinerator, Btu/hr.
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A-17.6.2.9 Calculate supplemental fuel requirement. Because
the suppl emental f uel also requires air for combus-
tion and this air must be heated, and more water is
formed by the reaction, the calculations in Subsec-
tions A-17.6.2.2 through A-17.6.2.8 can be carried
forward through several iterations. If this is
done, it will be seen that the actual supplemental
heat required is approximately double the value SH
determined in Subsection A-17.6.2.8 above. This
approximation is used below.
FQ _ (SH) (DRY) (HPD)
hu " 144,000
where
FO = Fuel oil required, gal/yr.
2 = Factor to account for fuel oil combustion heat
requirement.
1.1 = Factor to account for start-up fuel and ineffi-
ciencies.
144,000 = Heat content of fuel oil, Btu/gal.
A-17.6.3 Calculate annual electricity requirement.
E = [- 2.68 x 10"8 (SV)3 + 1.51 x 10"3 (SV)2 + 25.4 (SV) + 189,400]
where
E = Annual electrical energy requirement, kWhr.
A-17.7 Quantities Calculations Output Data
A-17.7.1 Annual operation and maintenance labor requirement, L, hr/yr.
A-17.7.2 Annual fuel oil requirement, FO, gal/yr.
A-17.7.3 Annual electrical energy requirement, E, kWhr/yr.
A-17.8 Unit Price Input Required
A-17.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-17.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
347
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A-17.8.3 Cost of operational labor, COSTL, $/hr. Default value =
$13.00/hr (ENRCCI/4,006).
A-17.8.4 Cost of fuel oil, COSTFO, $/gal . Default value = $l.,30/gal
(ENRCCI/4,006).
A-17.8. 5 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-17.9 Cost Cal culations
A-17. 9.1 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-17.9. 2 Annual cost of fuel oil.
COSTFUEL = (FO) (COSTFO)
where
COSTFUEL = Annual cost of fuel oil , $/yr.
A-17.9. 3 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-17.9. 4 Annual cost of maintenance parts and materials.
COSTMP = [- 1.3 x 10"10 (SV)3 - 3.0 x 10"6 (SV)2 + 0.87 (SV) + 8,166]
where
COSTMP = Annual cost of maintenance parts and materials, $/yr.
348
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A-17.9.5 Base capital cost of multiple hearth incinerator.
TBCC = [- 2.7 x 10"3 (SV)2 + 231.5 (SV) + 1,681,000] ~|~-
where
TBCC = Total base capital cost of multiple hearth incinerator, $.
A-17.9.6 Annual operation and maintenance cost.
COSTOM = COSTLB> COSTDSL + COSTEL + COSTMP
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-17.1Q Cost Calculations Output Data
A-l7.10.1 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-17.10.2 Annual cost of fuel oil, COSTFUEL, $/yr.
A-l7.10.3 Annual cost of electrical energy, COSTEL, $/yr.
A-17.10.4 Annual cost of maintenance parts and materials, COSTPM, $/yr.
A-17.10.5 Total base capital cost of multiple hearth incinerator facil-
ity, TBCC, $.
A-17.10.6 Total annual operation and maintenance cost for multiple hearth
incinerator, COSTOM, $/yr.
349
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APPENDIX A-18
COMPOSTING - WINDROW METHOD
A-18.1 Background
In windrow composting, dewatered sludge is mixed with a bulking agent and
spread on paved but uncovered areas in windrows with an approximately triangu-
lar or trapezoidal cross sectional area of 35 ft . The most economical and
most commonly used bulking agents in the windrow process are previously com-
posted sludge and sawdust. Windrows are approximately 14 ft wide, with access
areas between windrows of 10 ft. Windrows are 300 ft long, or less for small
plants. Sludge remains in windrows for approximately 30 days, with periodic
turning to maintain aerobic conditions and to provide mixing. At the end of
the composting period, the sludge is moved to a storage area for additional
curing. With properly controlled operation, high temperatures achieved during
composting can destroy virtually all pathogens and parasites. However, com-
post is a suitable medium for regrowth of bacteria, and precautions must be
taken to prevent reinfection. Windrow composting may be adversely affected by
cold or wet weather.
The algorithm presented below is based on the construction and operation
of a windrow composting facility with the following conditions:
* Windrow and access areas are paved with asphalt; the storage area is
unpaved.
* Dewatered sludge is mixed with previously composted sludge to obtain
an initial solids concentration of approximately 40 percent.
* Windrows are turned mechanically once a day for the first 2 weeks, and
three times per week thereafter.
• Compost mix remains in the composting area for 30 days.
Capital costs include purchase of land, site clearing and grading, paving
of composting area, purchase of windrow turning machine and front-end loader,
purchase and construction of unloading and mixing structure, and construction
of a maintenance and operation building. Operation and maintenance costs
include operation and maintenance labor, fuel for composting and ancillary
machinery, and O&M materials and supplies.
A-18.1.1 Algorithm Development
The following algorithm was developed for windrow composting using previ-
ously composted sludge as the bulking agent. Supplemental information was
obtained from Reference 4, pages 12-10 through 12-12 and pages 12-16 through
350
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12-22; and through correspondence with the Los Angeles County Sanitation Dis-
trict. The information obtained from references was fit to equations using a
multiple regression program.
The process is shown schematically in the flow diagram below. Reference
to the diagram should aid the reader in following the material balance calcu-
lations that follow. In these calculations, it is assumed that no changes
occur to the recycled compost used as bulking agent, since any further conver-
sion taking place in the recycled compost is negligible compared with the con-
version of solids in the dewatered sludge.
Windrow Composting Process
Dewatered
Sludge
Volatile Solids
Conversion and Drying
Compost
Recycled Compost
as Bulking Agent
A-18.2 Input Data
A-18.2.1 Daily dewatered sludge volume entering the composting process,
SV, gal/day.
A-18.2.2 Sludge solids concentration in dewatered sludge, SS, percent
dry solids.
A-18.2.3 Percent volatile solids in dewatered sludge, VSP, percent of
total solids dry weight.
A-18.2,4 Percent volatile solids destroyed during composting, VSC, per-
cent of sludge volatile solids dry weight.
351
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A-18.2.5 Compost solids content percent, CSP, percent dry solids.
A-18.2.6 Dewatered sludge specific weight, SC, Ib/yd3.
A-18.2.7 Compost product specific weight, SR, Ib/yd .
A-18.2.8 Mixed dewatered sludge and compost specific weight, SM, Ib/yd3.
A-18.2.9 Windrow cross section area, X, ft2.
A-18.2.10 Windrow length, LNTH, ft.
A-18.2.11 Truck unloading and mixing area, AUM, ft2/ton of dry solids/
day.
A-18.2.12 Finished compost storage area, ACS, ft2/ton of dry solids/day.
A-18.2.13 Fraction of total composting site area requiring clearing of
brush and trees, FWB, expressed as a decimal fraction.
A-18.2.14 Fraction of total composting site requiring light grading,
FRL6, expressed as a decimal fraction.
A-18.2.15 Fraction of total composting site requiring medium grading,
FRMG, expressed as a decimal fraction.
A-18.2.16 Fraction of total composting site requiring extensive grading,
FRE6, expressed as a decimal fraction.
A-18.3 Design Parameters
A-18.3.1 Daily dewatered sludge volume entering the composting process,
SV, gal/day. This input value must be provided by the user.
No default value.
A-18.3.2 Sludge solids concentration in dewatered sludge, SS, percent of
dewatered sludge weight. This input value should be provided
by the user. However, if no value is available, default value
= 20 percent.
A-18.3.3 Percent volatile solids in dewatered sludge, VSP, percent of
total solids dry weight. Default value = 35 percent.
A-18.3.4 Percent volatile solids destroyed during composting, VSC, per-
cent of sludge volatile solids dry weight. Default value = 30
percent.
A-18.3.5 Compost solids percent after composting, CSP. Default value =
65 percent.
A-18.3.6 Dewatered sludge specific weight, SC. Default value == 1,820
Ib/yd3.
352
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A-18.3.7 Compost product specific weight, SR. Default value = 865
lb/yd3.
A-18.3.8 Mixed dewatered sludge and compost specific weight, SM. De-
fault value = 1,685 lb/yd3.
A-18.3.9 Windrow cross section, X. Default value = 35 ft .
A-18.3.10 Windrow length, LNTH. Default value » 300 ft.
A-18.3.11 Truck unloading and mixing area, AUM. Default value = 300
ftvton of dry solids/day to be composted.
A-18.3.12 Finished compost storage area, ACS. Default value = 900
ft2/ton of dry solids/day to be composted.
A-18.3.13 Fraction of composting site requiring clearing of brush and
trees, FWB. Varies significantly depending on site-specific
conditions. Default value = .0.7 for composting sites.
A-18.3.14 Fraction of composting site requiring light grading, FRLG.
Varies significantly depending on site-specific conditions.
Default value = 0.3.
A-18.3.15 Fraction of composting site requiring medium grading, FRMG.
Varies significantly depending on site-specific conditions.
Default value = 0.4.
A-18.3.16 Fraction of composting site requiring extensive grading, FREG.
Varies significantly depending on site-specific conditions.
Default value = 0.3.
A-18.4 Process Design Calculations
A-18.4.1 Calculate daily wet weight of dewatered sludge to be composted.
ns - (SV) (8.34) F 1
(8.34) f
J.OOO) ]
(2soO) 100 - (SS) (SS)
100 (1.42) (100)
where
DS = Daily wet-weight of dewatered sludge, tons/day.
8.34 = Density of water, Ib/gal.
2,000 = Conversion factor, Ib/ton.
1.42 = Assumed specific gravity of sludge solids, unitless.
A-18.4.2 Calculate daily dry solids weight of dewatered sludge to be
composted.
DSS -
U55
(2,000)
- -
353
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where
DSS = Daily dry solids weight of dewatered sludge, Ib/day.
2,000 = Conversion factor, Ib/ton.
Note: In many cases, the user will know the daily dry solids weight of
dewatered sludge, DSS, prior to using the algorithm. If so, DS can be
back-calculated as follows:
A-18.4.3 Calculate weight of volatile solids in sludge composted per
day.
; (DSS)
where
VSS = Daily volatile dry solids weight, Ib/day.
A-18.4.4 Calculate sludge volatile solids destroyed during composting.
- (VSC) (VSS)
where
VSD = Sludge volatile solids destroyed during composting, Ib/day.
A-18.4.5 Calculate quantity of compost produced.
A-18.4.5,1 Tons of compost produced per day.
TPU = (DSS - VSD) (100)
PW (CSP) (2,000)
where
CPW = Compost produced, tons/day.
2,000 = Conversion factor, Ib/ton.
A-18.4.5. 2 Cubic yards of compost produced per day.
(DSS - VSD) (100)
(CSP) (SR)
354
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where
CPV = Compost produced, yd3/day.
A-18.4.6 Calculate quantity of compost product mixed with dewatered
sludge to obtain a solids content of 40 percent in the mixture.
Note: If SS is greater than 40, then R = 0.
A-18.4.6.1 Ratio of recycled compost product to dewatered
sludge.
R . °-40 -
(100) "*"
where
R = Lb compost product recycled/1b of dewatered sludge.
A-18.4.6.2 Weight of dewatered sludge composted per day.
(100)
(55)
where
WC = Weight of dewatered sludge, Ib/day.
A-18.4.6.3 Weight of recycled compost product.
WR = R x WC
where
WR = Weight of recycled product compost, Ib/day.
A-18.4.6.4 Volume of recycled compost product.
VR - WR
VR ~
where
VR = Volume of recycled compost product, yd^/day.
A-18.4.7 Calculate volume of mixed dewatered sludge and recycled compost
for composting in windrows.
VM = W°_ + WR
SC SR
355
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where
VM = Volume of mixed dewatered sludge and recycled compost for composting
windrows, yd3/day.
A-18.4.8 Calculate number of windrows required, based on a 30-day com-
posting period.
NW - (VM) (27) (30 days)
nn (X) (LNTH)
where
NW = Number of windrows with cross section, X, and length, LNTH.
27 = Conversion factor, ft*Vyd3.
A-18.4.9 Calculate area covered by windrows.
AM - (MM) (LNTH) (14)
AW ~ 43,560
where
AW = Area covered by windrows, acres.
14 = Width of windrows, ft*
43,560 = Conversion factor, ft Vac re.
A-18.4.10 Calculate total composting area.
AC . (NW * 1) [(10) (LNTH)] + AW
40,001)
where
AC = Total composting area, acres.
10 = Distance between windcows, ft.
43,560 = Conversion factor, ftVacre.
A-18.4.11 Calculate unloading and mixing area.
AU =
(DSS) (AUM)
(437550T (2,11007
where
AU = Unloading and mixing area, acres.
43,560 = Conversion factor, ftVacre.
2,000 = Conversion factor, Ib/ton.
356
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A-18.4.12 Calculate finished compost storage area.
AS =
(DSS) (ACS)
(43,560) (2,000)
where
AS = Finished compost storage area, acres.
43,560 = Conversion factor, ft2/acre.
2,000 = Conversion factor, Ib/ton.
A-18.4.13 Calculate total site area required.
TLAR =:(1.5) (AC + AU + AS)
where
TLAR = Total site area required, acres.
1.5 = A factor to account for area required for building and buffer
around the property.
A-18.4.14 Calculate housing area required.
HA = 1.263 x 10"5 (DS)3 - 0.013226 (OS)2 + 7.5783 (DS) + 841
where
HA = Housing area, ft2.
This equation is a multiple regression curve fit based on conceptual
building areas required for sludge composting operations between 50 and
600 tons/day of dewatered sludge solids.
A-18.5 Process Design Output Data
A-18.5.1 Dewatered sludge (wet weight) to be composted, DS, tons/day.
A-18.5.2 Dry solids weight of sludge to be composted, DSS, Ib/day.
A-18.5.3 Weight of compost produced, CPW, tons/day.
A-18.5.4 Volume of compost produced, CPV, yd3/day.
A-18.5.5 Weight of compost recycled to mix with dewatered sludge, WR,
Ib/day.
A-18.5.6 Volume of compost recycled to mix with dewatered sludge, VR,
yd3/day.
357
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A-18.5.7 Volume of mixed dewatered sJudge and recycled compost for com-
posting in windrows, VM, ydd/day,
A-18.5.8 Number of windrows required, NW.
A-18,5.9 Area required for composting, AC, acres.
A-18.5.10 Unloading and mixing area, AU, acres.
A-18.5.11 Storage area, AS, acres.
A-18.5.12 Total area required, TLAR, acres.
A-18.5.13 Housing area, HA, ft2.
A-18.6 Quantities Calculations
A-18.6.1 Calculate annual fuel requirement. Fuel for composting
machines and other equipment used in the windrow process is a
function of the quantity of dewatered sludge processed as fol-
1 ows:
FU
= 0.00057 (DS)3 - 0.53 (DS}2 + 413 (DS) + 15,000
where
FU = Annual fuel requirement, gal/yr.
This equation is a multiple regression curve fit based on fuel usage for
conceptual composting operations between 50 and 600 tons/day of dewatered
sludge.
A-18.6.2 Calculate operation and maintenance labor requirement. Opera-
tion and maintenance labor is a function of the quantity of
dewatered sludge processed as follows:
L - [- 0.033 (DS)2 + 60 (DS) + 2,020]
where
L= Operation and maintenance labor requirement, hr/yr.
This equation is a multiple regression curve fit based on labor require-
ments for conceptual composting operations between 50 and 600 tons/day of
dewatered sludge.
A-18.7 Quantities Calculations Output Data
A-18.7.1 Fuel requirement, FU, gal/yr.
358
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A-18.7.2 Operation and maintenance labor requirement, L, hr/yr.
A-18.8 Unit Price Input Required
A-18.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI.
A-18.8.2 Current Marshall and Swift Equipment Cost Index, MSECI.
A-18.8.3 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-18.8.4 Cost of operation and maintenance labor, COSTL, $/hr. Default
value = $13.00/hr (ENRCCI/4,006).
A-18.8.5 Cost of land, LANDCST, $/acre. Default value = $3,000/acre
(ENRCCI/4,006). :
A-18.8.6 Cost of clearing brush and trees, BCRCST, $/acre. Default
value = $l,500/acre (ENRCCI/4,006).
A-18.8.7 Cost of light grading earthwork, LGECST, $/acre. Default value
= $500/acre (ENRCCI/4,006).
A-18.8.8 Cost of medium grading earthwork, MGECST, $/acre. Default
value = $2,500/acre (ENRCCI/4,006).
A-18.8.9 Cost of extensive grading earthwork, EGECST, $/acre. Default
value = $5,000/acre (ENRCCI/4,006).
A-18.8.10 Cost of paving, PVCOST, $/acre. Default value = $58,000/acre
(ENRCCI/4,006) (reflects cost of bituminous concrete).
A-18.9 Cost Calculations ;
A-18.9.1 Total cost of land for composting site.
COSTLAND = (TLAR) (LANDCST)
where
COSTLAND = Total cost of land for composting site, $.
A-18.9.2 Cost of clearing brush and trees.
COSTCBT = (TLAR) (FWB) (BCRCST)
where
COSTCBT = Cost to clear brush and trees, $.
359
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A-18.9.3 Cost of grading earthwork.
COSTEW - (TLAR) [(FRLG) (LGECST) + (FRMG) (MGECST) + (FREG) (EGECST)]
where
COSTEW = Cost of earthwork grading, $.
A-18.9.4 Cost of paving windrow composting area.
COSTPV = (AC) (PVCOST)
where
COSTPV = Cost of paving windrow composting area, $.
A-18.9.5 Cost of equipment. Equipment cost is a function of the quan-
tity of dewatered sludge processed using the following equa-
tion:
COSTEQ » [1,560 (DS) + 450,000]
where
COSTEQ = Cost of equipment, $.
This equation is a multiple regression curve fit based on equipment cost
for conceptual composting operations between 5 and 600 tons/day of de-
watered sludge.
A-18.9.6 Cost of unloading and mixing structure.
(AUM) (20) ENRCCI
2,000 4,006
1 EN
J 4,
where
COSTUM - Cost of unloading and mixing structure, $.
20 = Construction cost of unloading and mixing structure, $/ft*>.
2,000 = Conversion factor, Ib/ton.
A-18.9.7 Cost of operation and maintenance building.
COSTH = (HA) (50)
360
-------
where
COSTH = Cost of operation and maintenance building, $.
50 = Construction cost of operation and maintenance building, $/ft2.
A-18.9.8 Cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-18.9.9 Annual fuel cost.
COSTFL = (FU) (COSTDF)
where
COSTFL = Annual cost of fuel , $/yr.
A-18.9.10 Annual cost of parts and material.
COSTPM = (0.18) (COSTEQ)
where
COSTPM = Annual parts and material cost, $/yr.
0.18 = Annual replacement parts and materials, percent of equipment
cost.
A-18.9.11 Total base capital cost.
TBCC = COSTLAND + COSTCBT + COSTEW + COSTPV + COSTEQ + COSTUM + COSTH
where
TBCC = Total base capital cost, $.
A-18.9.12 Annual operation and maintenance cost.
COSTOM = COSTLB + COSTFL + COSTPM
361
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where
COSTOH = Total operation and maintenance cost, $/yr.
A-18.10 Cost Calculations Output Data
A-18.10.1 Cost of land for composting site, COSTLAND, $.
A-18.10.2 Cost to clear brush and trees from site, COSTCBT, $.
A-18.10.3 Cost of grading earthwork, COSTEW, $.
A-18.10.4 Cost of paving, windrow composting area, COSTPV, $.
A-18.10.5 Cost of composting equipment, CQSTEQ, $.
A-18.10.6 Cost of unloading and mixing structure, COSTUM, $.
A-18.10.7 Cost of operation and maintenance building, COSTH, $.
A-18.10.8 Annual cost of operation and maintenance labor, COSTLB, $/yr,
A-18.10.9 Annual cost of fuel, COSTFL, $/yr.
A-18.10.10 Annual cost of parts and material, COSTPM, $/yr.
A-18.10.11 Total base capital cost, TBCC, $.
A-18.10.12 Annual operation and maintenance cost, COSTOM, $/yr.
362
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APPENDIX A-19
COMPOSTING - AERATED STATIC PILE METHOD
A-19.1 Background
Aerated static pile composting is similar in principle to windrow com-
posting, previously discussed in Appendix A-18. However, in the aerated
static pile composting process, the mixture of dewatered sludge and bulking
agent remains fixed (as opposed to the periodic turning procedure used in the
windrow method), and a forced ventilation system maintains aerobic conditions.
A layer of previously composted sludge placed over the surface of the pile
provides insulation, allowing for high temperatures throughout the pile.
Because the piles do not need to be turned, and the outer layer of previously
composted sludge provides insulation, static pile composting is less affected
by inclement weather than windrow composting. Both digested and raw dewatered
sludges have been composted by this technique.
Bulking agents used in aerated static pile composting include wood chips,
rice hulls, or straw. Previously composted sludge is not a suitable bulking
agent, since a porous structure must be maintained to allow movement through
the pile. This algorithm assumes the use of wood chips as the bulking agent.
Composting, even with the aerated static pile method, is largely a mate-
rials handling process, and most systems in the United States use mobile
equipment. Labor and bulking agent are the largest operating cost components.
The physical characteristics of the sludge and bulking agent must be
defined at various stages of the process. Volatile solids and water are
removed during processing, which substantially reduces the sludge weight but
does not appreciably reduce the volume.
The aerated static pile process in this algorithm consists of (1) unload-
ing and mixing, (2) aerated pile composting, (3) drying, (4) screening, and
(5) storage. An area is also provided for storage of bulking agent.
1. Unloading and mixing. Dewatered sludge is delivered to the unloading
and mixing structure. The structure is covered and paved. Sludge is
unloaded directly onto a bed of bulking agent (wood chips). The
sludge and bulking agent are then mixed with a mobile composting/
mixing machine or front-end loader, depending on the size of the
operation.
2. Composting. The sludge/bulking agent mixture is moved from the un-
loading and mixing structure to composting pads by front-end loader.
Composting pads are paved but uncovered, with aeration piping and
drainage collection permanently installed in trenches. One blower is
363
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provided for each 2,400 ft/ of composting area. Sludge is placed in
the extended pile configuration and insulated with screened finished
compost. Space is provided for 30 days of composting and curing.
3. Drying. A covered and paved structure provides 5 days of drying
time. The structure is open on both ends, similar to the unloading
and mixing structure. The sludge/bulking agent mixture is moved from
the composting pads to the drying area and turned to achieve at least
50 percent solids by natural drying.
4. Screening. The sludge/bulking agent mixture is moved from the drying
structure by a front-end loader to a totally enclosed screening
building. Screening removes about 75 percent of the bulking agent.
Compost is transferred to an unpaved and uncovered storage area, and
screened bulking agent is returned to the unloading and mixing struc-
ture.
A-19.1.1 Algorithm Development
Design and cost equations in the following algorithm are based on Refer-
ence 4» pages 12-22 through 12-36. Additional data for O&M requirements were
taken from Reference 7, page A-181.
The process is shown schematically in the flow diagram below. Reference
to the diagram should aid the reader in following the material balance calcu-
lations that follow. In these calculations, it is assumed that no changes
occur to the bulking agent during composting, since any conversion of the
bulking agent should be negligible compared to conversion of volatile solids
in the dewatered sludge.
Static Pile
Composting
Dewatered
Sludge
Make-Up
Volatile Solids
Conversion
and Drying
Screening
Recycled Bulking Agent
Compost
Bulking Agent
364
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A-19.2 Input Data
A-19.2.1 Daily dewatered sludge volume entering the composting process,
SV, gal/day.
A-19.2.2 Sludge solids concentration in dewatered sludge, SS, percent
dry solids.
A-19.2.3 Volatile solids in dewatered sludge, VSP, percent of total
solids dry weight.
A-19.2.4 Percent volatile solids destroyed during composting, VSC, per-
cent of sludge volatile solids dry weight.
A-19.2.5 Compost solids content percent, CSP, percent dry solids.
A-19.2.6 Compost product specific weight, SR, lb/yd3.
A-19.2.7 Mixed dewatered sludge and bulking agent specific weight, SM,
1-b/yd3.
A-19.2.8 Bulking agent mixing ratio, BA, yd3/ton dewatered sludge.
A-19.2.9 New bulking agent mixing ratio, NB, fraction of total BA.
A-19.2.10 New bulking agent specific weight, SNB, lb/yd3.
A-19.2.11 Recycled bulking agent mixing ratio, RB, fraction of total BA.
A-19.2.12 Recycled bulking agent specific weight, SRB, lb/yd3.
A-19.2.13 Bulking agent in compost product, BP, Ib/day.
A-19.2.14 Truck unloading and mixing area, AUM, ft2/ton of dry solids/
day.
A-19.2.15 Composting area, AC, ft2/ton of dry solids/day.
A-19.2.16 Drying area, AD, ft2/ton of dry solids/day.
A-19.2.17 Finished compost storage area, ACS, ft2/ton of dry solids/day.
A-19.2.18 Bulking agent storage area, AB, ft2/ton of dry solids/day.
A-19.2.19 Fraction of total composting site area requiring clearing of
brush and trees, FWB, expressed as a decimal fraction.
A-19.2.20 Fraction of total composting site area requiring light grading,
FRL6, expressed as a decimal fraction.
A-19.2.21 Fraction of total composting site area requiring medium grad-
ing, FRM6, expressed as a decimal fraction.
365
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A-19.2.22 Fraction of total composting site area requiring extensive
grading, FREG, expressed as a decimal fraction.
A-19.3 Design Parameters
A-19.3.1 Daily dewatered sludge volume entering the composting process,
SV, gal/day. This input value must be provided by the user.
No default value.
A-19.3.2 Sludge solids concentration in dewatered sludge, SS.. This
input value should be provided by the user whenever possible.
However, if no value is available, default value = 20 percent.
A-19.3.3 Percent volatile solids in dewatered sludge, VSP, percent of
total solids dry weight. Default value = 35 percent.
A-19.3.4 Percent volatile solids destroyed during composting, VSC, per-
cent of sludge volatile solids dry weight. Default value = 45
percent.
A-19.3.5 Compost product percent solids, CSP. Default value = 65 per-
cent.
A-19.3.6 Compost product specific weight, SR. Default value = 1,000
lb/yd3.
A-19.3.7 Mixed dewatered sludge and bulking agent specific weight, SM.
Default value = 1,100 lb/yd3.
A-19.3.8 Bulking agent mixed with dewatered sludge, BA. Default value =
2.5 yd3/ton dewatered sludge.
A-19.3.9 New bulking agent mixing ratio, NB. Bulking agent is a func-
tion of several factors, including quantity and solids content
of sludge processed, characteristics of the bulking agent* and
efficiency of screening. Default value = (BA) (0.25) yd3/ton
dewatered sludge.
A-19.3.10 New bulking agent specific weight, SNB. Default value = 500
lb/yd3.
A-19.3.11 Recycled bulking agent mixing ratio, RB. Default value = (BA)
(0.75) yd^/ton dewatered sludge.
A-19.3.12 Recycled bulking agent specific weight, SRB. Default value =
600 lb/yd3.
A-19.3.13 Bulking agent in compost product, BP. Default value is calcu-
lated by:
RP - (NB) (SRB)'(DSS) (100)
D (SS) (2,QUO)~
366
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where
BP = Bulking agent compost product, Ib/day.
2,000 = Conversion factor, Ib/ton.
A-19.3.14 Truck unloading and mixing area, AUM. Default value = 300
ftvton of dry solids/day to be composted.
A-19.3.15 Composting area, AC. Default value = 7,000 ft2/ton dry
solids/day to be composted.
A-19.3.16 Drying area, AD. Default value = 300 ft2/ton dry solids/day to
be composted.
A-19.3.17 Finished compost storage area, ACS. Default value = 900 ft2/
ton dry solids/day to be composted. Equivalent to approxi-
mately 9 days of storage.
A-19.3.18 Bulking agent storage area, AB. Default value = 2,000 ft2/ton
dry solids/day to be composted.
A-19.3.19 Fraction of composting site requiring clearing of brush and
trees, FWB. Varies significantly depending on site-specific
conditions. Default value = 0.7.
A-19.3.20 Fraction of composting site requiring light grading, FRLG.
Varies significantly depending on site-specific conditions.
Default value = 0.3.
A-19.3.21 Fraction of composting site requiring medium grading, FRMG.
Varies significantly depending on site-specific conditions.
Default value = 0.4.
A-19.3.22 Fraction of composting site requiring extensive grading, FREG.
Varies significantly depending on site-specific conditions.
Default value =0.3.
A-19.4 Process Design Calculations
A-19.4.1 Calculate daily wet weight of dewatered sludge to be composted.
nc _ JSV) (8.34)
(2,000)
100 - (SS) . (SS)
1UO(1.42) :
!) (100)
where
DS = Daily wet weight of dewatered sludge, tons/day.
8.34 = Density of water, Ib/gal.
2,000 = Conversion factor, Ib/ton.
1.42 = Assumed specific gravity of sludge solids.
367
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A-19.4.2 Calculate daily dry solids weight of dewatered sludge to be
composted.
_ (2,000) (SS) (PS)
~
where
DSS = Daily dry solids weight of dewatered sludge, Ib/day.
2,000 = Conversion factor, Ib/ton.
Note: In many cases, the .user will know the daily dry solids weight of
dewatered sludge, DSS, prior to using the program. If so, DS can be
back-calculated as follows:
DS =
(SS) (2,000)
Similarly, SV can be back-calculated, using the formula in Appendix
A-19.4.1.
A-19.4.3 Calculate bulking agent in compost product, BP, default value,
if required.
RP = (NB) (SRB) (DSS) (100)
(SS) (2,000)
where
BP = Default value for BP, Ib/day.
2,000 = Conversion factor, Ib/ton.
A-19.4.4 Calculate weight of volatile solids in sludge composted per
day.
where
VSS = Daily volatile solids weight, Ib/day.
A-19.4.5 Calculate volatile solids destroyed during composting.
= (VSC) (VSS)
nra
368
-------
where
VSD = Sludge volatile solids weight destroyed during composting,
Ib/day.
A-19.4.6 Bulking agent required.
A-19,4.6.1 Calculate weight of bulking agent.
(NB) (SNB) + (RB) (SRB)
where
BAW = Bulking agent weight, tons/day.
2,000 = Conversion factor, Ib/ton.
A-19.4.6. 2 Calculate volume of bulking agent.
BAV = (BA) (DS)
where
BAV = Bulking agent volume, yd^/day.
A-19.4.7 Calculate volume of mixed dewatered sludge and bulking agent to
be composted.
MV --(PS + BAW) (2.000)
nv ^_^
where
O
MV = Volume of mixed sludge and bulking agent to be composted, yd /day.
A-19.4.8 Calculate volume of screened compost required for insulation of
aerated piles.
SCV - (OSS) (2.15)
where
SCV = Volume of screened compost, yd vday.
369
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A-19.4.9 Quantity of compost produced,
A-19.4.9.1 Calculate weight of compost produced
_ DSS - VSD + BP
-
where
CPW = Compost produced, tons/day.
A-19.4.9. 2 Calculate volume of compost produced.
PPV = (DSS - VSD + BP) (100)
(CSP) (SR)
where
CPV = Compost produced, yd3/day.
A-19.4.1Q Calculate total area required.
AT - n z\ (m^\ (AUM + AC + AD + ACS + AB)
MI - u-o; l"«J (43,560) (2,000)
where
AT = Total area required, acres.
1.5 = Factor to account for additional land area required for buffer,
storage, etc.
A-19.4.11 Calculate housing area required.
HA = (0.000028735) (DS)3 - (0.029885) (DS)2 + (16.161) (DS) + 1,600
where
o
HA = Building area, ft •
This equation is a multiple regression curve fit based on conceptual
building areas required for sludge composting operations between 50 and
600 tons /day of dewatered sludge solids.
A-19.5 Process Design Output Data
A-19.5.1 Dewatered sludge : (wet weight) to be composted, DS, tons/day.
A-19.5. 2 Dry solids weight of sludge to be composted, DSS, Ib/day.
370
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A-19.5.3 Weight of bulking agent required, BAW, tons/day.
A-19.5.4 Volume of bulking agent required, BAV, yd^/day.
A-19.5.5 Volume of mixed sludge and bulking agent to be composted, MV,
yd-Vday.
A- 19. 5. 6 Weight of compost produced, CPW, tons/day.
A-19.5.7 Volume of compost produced, CPV, y
A-19.5.8 Compost recycled to insulate aerated piles, SCV, yd^/day.
A-19.5,9 Total area required, AT, acres.
A-19.5.10 Building area required, HA, ft .
A-19.6 Quantities Calculations
A-19.6.1 Calculate annual fuel usage. Fuel for mixing machines and
other mobile equipment used in the process is a function of the
quantity of dewatered sludge processed:
FU = [- (0.1016) (DS)2 -l- (222.64) (OS) + (7,744)]
where
FU = Annual fuel requirement, gal/yr.
This equation is a multiple regression curve fit based on fuel usage for
conceptual composting operations between 50 and 600 tons/day of dewatered
sludge.
A-19.6. 2 Calculate annual electrical energy requirement. Electricity
for aeration and screening is a function of the quantity of
dewatered sludge processed:
EU = (DS) (400)
where
EU = Annual electrical energy requirement, kWhr/yr.
A- 19. 6. 3 Calculate annual bulking agent required.
BAU « (NB) (DS) (365)
371
-------
where
BAU = Bulking agent usage, yd3/yr.
A-19.6.4 Calculate annual '•. operation and maintenance labor requirement.
Operation and maintenance labor is a function of the quantity
of dewatered sludge processed.
L = [- (0.0331) (DS)2 + (61.03) (DS) + (1,959)]
where
L = Operation and maintenance labor requirement, hr/yr.
This equation is a multiple regression curve fit based on labor require-
ments for conceptual composting operations between 50 and 600 tons/day of
dewatered sludge.
A-19.7 Quantities Calculations Output Data
A-19.7.1 Annual fuel requirement, FU, gal/yr.
A-19.7.2 Annual electrical energy requirement, EU, kWhr/yr.
A-19.7.3 Annual bulking agent required, BAU, yd^/yr.
A-19.7.4 Annual operation and maintenance labor requirement, L, hr/yr.
A-19.8 Unit Price Input Required
A-19.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI.
A-19.8.2 Current Marshall and Swift Equipment Cost Index, MSECI.
A-19.8.3 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-19.8.4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-19.8.5 Cost of bulking agent, COSTB, $/yd3. Default value =
115.00/yd-3 (ENRCCI/4,006).
A-19.8.6 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-19.8.7 Cost of land, LANDCST, $/acre. Default value = $3,000/acre
(ENRCCI/4,006).
A-19.8.8 Cost of clearing brush and trees, BCRCST, $/acre. Default
value = $l,500/acre (ENRCCI/4,006).
372
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A-19.8.9 Cost of light grading earthwork, LGECST, $/acre. Default value
= $l,000/acre (ENRCCI/4,006).
A-19.8.10 Cost of medium grading earthwork, MGECST, $/acre. Default
value = $2,500/acre (ENRCCI/4,006).
A-19.8.11 Cost of extensive grading earthwork, EGECST, $/acre. Default
value = $5,000/acre (ENRCCI/4,006).
A-19.9 Cost Calculations
A-19.9.1 Cost of land.
COSTLAND = (AT) (LANDCST)
where
COSTLAND = Total land cost for composting site, $.
A-19.9. 2 Cost of clearing brush and trees.
COSTCBT = (AT) (FWB) (BCRGST)
where
COSTCBT = Total cost to clear brush and trees, $.
A-19.9. 3 Cost of grading earthwork.
COSTEW = (AT) [(FRLG) (LGECST) + (FRMG) (MGECST) + (FREG) (EGECST)]
where
COSTEW - Cost of earthwork grading, $.
A-19.9. 4 Cost of composting pad construction. This cost includes con-
struction of pads and purchase and installation of piping and
blowers.
COSTCP = r(DSS) (AC) (3.15)-. ENRCCI
OU5ILF L -I
where
COSTCP = Cost of composting pads, $.
3.15 = Unit cost of composting pads, $/ft
373
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A-19.9.5 Cost of equipment. Mobile equipment and screening equipment
costs are a function of the quantity of dewatered sludge pro-
cessed using the following equation:
COSTEQ = [- 5.4 (DS)2 + 5,855 (DS) + 435,000] ——•
where
COSTEQ = Total cost of equipment, $.
This equation is a multiple regression curve fit based on the 1983 cost
of equipment required for composting operations.
A-19.9.6 Cost of unloading, and mixing structure.
COSTUM - r
-------
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-19.9.10 Annual cost of fuel.
COSTFL = (FU) (COSTDF)
where
COSTFL = Annual cost of fuel, $/yr.
A-19.9.11 Annual cost of electrical energy.
COSTEL = (EU) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-19.9.12 Cost of bulking agent.
COSTBA = (BAU) (COSTB)
where
COSTBA = Annual cost of bulking agent, $/yr.
A-19.9.13 Annual cost of parts and material.
COSTPM = (0.15) (COSTEQ)
i +s *.
where
COSTPM = Cost of parts and material, $/yr.
0.15 = Annual cost of parts and materials is assumed to be 15 percent of
equipment capital cost.
A-19.9.14 Total base capital cost.
TBCC = COSTLAND + COSTCBT + COSTEW + COSTCP + COSTEQ + COSTUM + COSTD + COSTH
375
-------
where
TBCC = Total base capital cost, $.
A-19.9.15 Annual operation and maintenance cost.
COSTOM = COSTLB + COSTFL + COSTEL + COSTBA + COSTPM
where
COSTOM = Total operation and maintenance cost, $/yr.
A-19.10 Cost Calculations Output Data
A-19.10.1 Cost of land for composting site, COSTLAND, $.
A-19.10.2 Cost to clear brush and trees from site, COSTCBT, $.
A-19.10.3 Cost of grading earthwork, COSTEW, $.
A-19.10.4 Cost of composting pad construction; COSTCP, $.
A-19.10.5 Cost of equipment, COSTEQ, $.
A-19.10.6 Cost of unloading and mixing structure, COSTUM, $.
A-19.10.7 Cost of drying structure, COSTD, $.
A-19.10.8 Cost of operation and maintenance building, COSTH, $.
A-19.10.9 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-19.10.10 Annual cost of fuel, COSTFL, $/yr.
A-19.10.11 Annual cost of electrical energy, COSTEL, $/yr.
A-19.10.12 Annual cost of bulking agent, COSTBA, $/yr.
A-19.10.13 Annual cost of parts and material, COSTPM, $/yr.
A-19.10.14 Total base capital cost, TBCC, $.
A-19.10.15 Annual operation and maintenance cost, COSTOM, $/yr.
376
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APPENDIX A-20
LIQUID SLUDGE TRUCK HAULING,
INCLUDING SLUDGE LOADING FACILITIES
A-20.1 Background
Truck hauling is a flexible and widely used method for transporting
sludge to a disposal site or other sludge management facility. Truck hauling
is most applicable at small- and medium-sized treatment facilities. One
advantage of truck hauling is the flexibility that it provides, since terminal
points and haul routes can be changed readily at relatively low cost. Gen-
erally, truck hauling is more economical than railroad or pipeline when trans-
porting sludges less than 150 miles. Diesel-equipped vehicles are the eco-
nomic choice for larger trucks and trucks with high annual mileage operation.
Specially designed tank trucks are used for hauling liquid sludge (sludge
containing less than 15 percent solids). Tank configurations and volumes vary
depending on sludge loading and unloading times, haul distance, and frequency
of trips. In most applications, tanker trucks for hauling liquid sludge are
usually less than 6,000 gallons. Tanker dimensions and maximum load of the
vehicle are limited by state law.
In the following algorithm, capital costs include purchase of specially
designed tank trucks and construction of sludge loading facilities at the
treatment plant. The loading facility consists of a concrete slab and appro-
priate piping and valving set at a height of 12 ft to load the tanker from the
top. Base annual O&M costs include driver labor, operational labor, fuel,
vehicle maintenance, and loading facility maintenance.
A-20.1.1 Algorithm Development
Fuel and labor requirements used for computation of O&M cost equations in
this algorithm were derived from communications with truck and equipment manu-
facturers. Additional information used in development of cost equations was
obtained from Reference 11, pages 6, 7, 31, 33, 39, 40, 42, 60, 61, 62, and
66.
A-20.2 Input Data
A-20.2.1 Daily sludge volume, SV, gal/day.
A-20.2.2 Truck loading time at treatment plant, LT, hr.
A-20.2.3 Truck unloading time at disposal site, ULT, hr.
377
-------
A-20.2.4 Round trip haul time from treatment plant to disposal site,
RTHT, hr.
A-20.2.5 Round trip haul distance from treatment plant to disposal site,
RTHD, miles.
A-20.2.6 Work schedule for hauling, HPD, hr/day.
A-20.2.7 Number of days/yr when sludge is hauled, DRY, days/yr.
A-20.3 Design Parameters
A-20.3.1 Daily sludge volume, SV, gal/day. This input value must be
furnished by the user. No default value.
A-20.3.2 Truck loading time at treatment plant, LT, hr. Default value =
0.4 hr.
A-20.3.3 Truck unloading time at disposal site, ULT, hr. Default value
= 0.8 hr. See table below for guidance.
TYPICAL TRUCK UNLOADING TIME AS A FUNCTION
OF TYPE OF DISPOSAL UTILIZED
Typical Unloading
Type of Disposal Time, Hr
Landfill 0.4
Storage lagoon at disposal site 0.4
Agricultural utilization 1.0
Forest land utilization 1.5
Land reclamation utilization 1.0
Dedicated disposal site 0.6
A-20.3.4 Round trip haul time, from treatment plant to disposal site,
RTHT, hr. No default value. This value must be input by user.
If not available, this value can be estimated using an average
mph for truck hauling, as follows:
A-20.3.4.1 Urban travel.
RTUT _ Round trip distance in miles
2b miles/hr average speed
A-20.3.4.2 Rural travel.
_ Round trip distance in miles
3b miies/nr average speed
378
-------
A-20.3.4.3 Highway travel.
_ Round trip distance in miles
45 miles/hr average speed
where
RTHT = Round trip haul time, hr.
A-20.3.5 Round trip haul distance from treatment plant to disposal site,
RTHD, miles. No default value. If several sludge disposal
sites are planned, e.g., private farmer agricultural utiliza-
tion, use average distance to sites.
A-20.3.6 Daily work schedule for hauling, HPD, hr/day. Default value =
7 hr/day.
A-20.3.7 Days/yr of sludge hauling, DRY, days. Default value = 180
days/yr. See table below for guidance.
TYPICAL DAYS PER YEAR OF SLUDGE HAULING AS A FUNCTION OF
TYPES OF DISPOSAL USED AND GEOGRAPHICAL REGION
Geographical Typical Days/Yr
Type of Disposal Region of Sludge Hauling
Landfill or storage Northern U.S. 230
lagoon at disposal site Central U.S. 250
Sunbelt States 260
Agricultural or land Northern U.S. 100
reclamation utilization Central U.S. 120
Sunbelt States 140
Forest land utilization Northern U.S. 160
Central U.S. 180
Sunbelt States 200
Dedicated disposal site Northern U.S. 160
Central U.S. 180
Sunbelt States 200
A-20.4 Process Design Calculation
A-20.4.1 Number and capacity of sludge haul trucks. Liquid sludge is
hauled in tanker trucks with capacities between 1,600 and 6,000
gal. The capacity of the tank trucks utilized is a function of
the volume of sludge to be hauled per day and the round trip
haul time. Special tanker capacities available are 1,6QO»
2,000, 2,500, 3,000, 4,000, and 6,000 gallons.
379
-------
A-20.4.1.1 Total volume hauled per trip.
FArrnB - SV (IT + ULT 4 RTHT) (365)
I-M-IUK - HpD (DpY)
where
FACTOR = Gallons hauled per trip if only one truck were
utilized.
A-20.4.1.2 Number of vehicles and capacity of each truck. The
number of vehicles is calculated using FACTOR and
the following matrix:
Number, NTR, and Capacity
FACTOR, gal of Tanker Trucks, CAP, Gal
<1,600 1 at 1,600
>1»600 but <2,500 1 at 2,500
>2,500 but <4,000 1 at 4,000
>4,000 but <8,000 2 at 4,000
>8,000 but <12,000 2 at 6,000
>12,000 All 6,000
If FACTOR exceeds 12,000, NTR - (Round to next highest integer.)
o 9 UUU
where
CAP = Capacity of tanker trucks required, gal, calculated from above
matrix.
NTR = Number of trucks required. Calculated from the above matrix.
A-20.5 Process Design Output Data
A-20.5.1 Capacity of tanker trucks, CAP, gal.
A-20.5. 2 Number of trucks required, NTR.
A-20.6 Quantities Calculations
A-20.6.1 Number of round trips/yr.
NRT - SV..J!65)
NKI -- pj-p -
where
NRT = Number of round trips/yr.
380
-------
A-20.6.2 Driver labor requirement
DT = [LT + ULT + RTHT] NRT
where
DT = Driver labor requirement, hr/yr.
A-20.6.3 Calculate annual fuel requirement. Vehicle fuel usage is a
function of truck size. The following fuel usage values are
typical for different capacity trucks.
Truck Capacity, CAP, gal Fuel Consumption, FC, mpg
1,600 8
2,500 7
4,000 6
6,000 5
j (RTHD) (NRT)
hu ~ FC
where
FU = Annual fuel requirement, gal/yr
FC = Fuel consumption rate, mpg, see table above.
A-20.7 Quantities Calculations Output Data
A-20.7.1 Number of round trips/yr, NRT.
A-20.7.2 Driver labor requirement, DT, hr/yr.
A-20.7.3 Annual fuel requirement, FU, gal/yr.
A-20.8 Unit Price Input Required
A-20.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI, at time cost analysis is made.
A-20.8.2 Current Marshall and Swift Equipment Cost Index, MSECI, at time
cost analysis is made.
A-20.8.3 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-20.8.4 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
381
-------
A-20,9 Cost Calculations
A-20.9.1 Cost of sludge tahker trucks.
TTCOST = (NTR) (COSTSTT)
MSECI
where
TTCOST
COSTSTT
Total cost of all sludge tanker trucks, $.
Cost per sludge tanker truck, obtained from the table below,
TankerCapacity, CAP, gal
1,600
2,500
4,000
6,000
Cost of Truck,
COSTSTT. 1983 $
60,000
80,000
100,000
120,000
A-20.9.2 Cost of vehicle loading area facilities. The tanker truck
loading facilities are assumed to consist of a concrete slab,
appropriate piping and valving to a height of 12 ft to load the
tanker from the top. Cost of the loading area facilities are
assumed to be a function of sludge volume, SV, in gal/yr. The
relationship of SV to loading area facilties cost is graduated
in a stepped manner.
COSTLA - (CSTLAB)
where
COSTLA = Total capital cost of loading area facilities, $.
CSTLAB = Base cost of loading area facilities, $. This is a function of
the annual volume of sludge hauled, SV, in gal/yr, and can be
obtained from the table below.
Annual Volume of Sludge
Hauled, SV x 365, gal/yr
100,000 to 500,000
500,000 to 1,000,000
1,000,000 to 2,000,000
2,000,000 to 4,000,000
4,000,000 to 8,000,000
8,000,000 to 12,000,000
12,000,000 to 16,000,000
16,000,000 to 20,000,0|00
20,000,000 and over !
Base Cost of Loading Area
Facilities. COSTLAB, $
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
382
-------
A-20.9.3 Annual vehicle maintenance cost. Maintenance cost per vehicle
mile traveled is a function of truck capacity and initial cost
of truck. The following factors are used to calculate vehicle
maintenance costs.
Truck Capacity, Maintenance Cost, MCM,
CAP. Gal $/nrile Traveled. 1983
1,600 0.28
2,500 0.32
4,000 0.36
6,000 0.40
VMC = (RTHD) (NRT) (MCM)
where
VMC - Annual vehicle maintenance cost, $.
MCM = Maintenance cost per mile traveled, $/mile from table above.
A-20.9.4 Loading area facility annual maintenance cost. For the pur-
poses of this program, it is assumed that loading area facili-
ties annual maintenance cost is a function of loading area
facility capital cost.
MCOSTLA = (COSTLA) (0.05)
where
MCOSTLA = Annual maintenance cost for loading facilities, $/yr.
0.05 = Assumed annual maintenance cost factor as a function of total
loading area facility capital cost.
A-20.9.5 Annual cost of operation labor
COSTLB - (DT) (COSTL) (1.2)
where
COSTLB = Annual cost of operation labor, $/yr.
1.2 = A factor to account for additional labor required at the loading
facility.
383
-------
A-20.9.6 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-20.9.7 Total base capital cost.
TBCC = TTCOST + COSTLA
where
TBCC = Total base capital cost, $.
A-20.9.8 Annual operation and maintenance cost.
COSTOM = (VMC) + (MCOSTLA) + (COSTLB) + (COSTDSL)
where
COSTOM - Total annual operation and maintenance cost, $/yr.
A-20.10 Cost Calculation Output Data
A-20.10.1 Total cost of sludge tanker trucks, TTCOST, $.
A-20.10.2 Total capital cost of loading area facilities, COSTLA, $.
A-20.10.3 Annual vehicle maintenance cost, VMC, $/yr.
A-20.10.4 Annual loading facility maintenance cost, MCOSTLA, $/yr,
A-20.10.5 Annual cost of operation labor, COSTLB, $/yr.
A-20.10.6 Annual cost of diesel fuel, COSTDSL, $/yr.
A-20.10.7 Total base capital cost, TBCC, $.
A-20.10.8 Total annual operation and maintenance cost, COSTOM, $/yr.
384
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APPENDIX A-21
DEWATERED SLUDGE TRUCK HAULING,
INCLUDING SLUDGE LOADING FACILITIES
A-21.1 Background
Truck hauling is a commonly employed sludge transport method, particu-
larly at small and medium treatment facilities. Truck hauling is less capi-
tal-intensive than other transport methods for hauling sludges over distances
less than 150 miles. An additional benefit of this method is the flexibility
that it provides when changing terminal points and haul routes.
Dewatered sludge (sludge, containing more than 15 percent solids) is
hauled in trucks similar to general purpose or standard highway trucks.
Trucks are covered to minimize nuisances and to prevent inadvertent spillage.
Standard truck capacities range from 7 to 36 yd3; however, maximum loads are
limited by state laws. Diesel-equipped vehicles are generally the most eco-
nomic choice for larger trucks and trucks with high annual mileage operation.
Capital costs in the following algorithm include construction of a truck
loading facility designed to accommodate the sludge volume within the operat-
ing schedule. Costs include construction of a concrete loading slab, and pur-
chase of skip loaders and trucks. Annual O&M costs include vehicle and load-
ing facility maintenance, driver and operational labor, and diesel fuel for
vehicles.
A-21.1.1 Algorithm Development
In the following algorithm, cost and O&M requirement equations were
developed from Reference 11, Pages 10, 11, 28, 30, 32, 34, 39, 41, 43, 60, 61,
62, and 66. Additional information used in cost equations was supplied by
truck and equipment manufacturers.
A-21.2 Input Data
A-21.2.1 Daily sludge volume, SV, gal/day.
A-21.2.2 Truck loading time at treatment plant, LT, hr.
A-21.2.3 Truck unloading time at disposal site, ULT, hr.
A-21.2.4 Round trip haul time from treatment plant to disposal site,
RTHT, hr.
385
-------
A-21.2.5 Round trip haul distance from treatment plant to disposal site,
RTHD, miles.
A-21.2.6 Work schedule for hauling, HPD, hr/day.
A-21.2.7 Number of days/yr when sludge is hauled, DRY, days/yr.
A-21.3 Design Parameters
A-21.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-21.3. 2 Truck loading time at treatment plant, LT, hr. Default value =
0.4 hr.
A-21.3. 3 Truck unloading time at disposal site, ULT, hr. Default value =
0.8 hr. See table below for guidance.
Typical Unloading
Type of Disposal Time, ULT, hr
Landfill 0.4
Storage lagoon at disposal site 0.4
Agricultural utilization 1.0
Forest land utilization 1.5
Land reclamation utilization 1.0
Dedicated disposal site 0.6
A-21.3. 4 Round trip haul time from treatment plant to disposal site,
RTHT, hr. No default value. This value must be input by user.
If a value is not available, it can be estimated using average
miles per hour for haul truck, as follows:
A-21.3. 4.1 Urban, travel.
_ Round trip distance in miles
25 miles per hour average speed
A-21.3. 4. 2 Rural travel,
RTHT = Ro"nd trip distance in miles
35 miles per hour average speed
i
!
A-21.3. 4. 3 Highway travel .
n-ru-r _ Round trip distance in miles
45 miles per hour average speed
386
-------
where
RTHT = Round trip haul time, hr,
A-21.3.5 Round trip haul distance from treatment plant to disposal site,
RTHD, miles. No default value. If several sludge disposal
sites are planned, e.g., private farmer agricultural utiliza-
tion, use average distance to sites.
A-21.3.6 Daily work schedule for hauling, HPD, hr/day. Default value =
7 hr/day.
A-21.3.7 Days/yr of sludge hauling, DPY, days/yr. Default value = 180
days per year. See table below for guidance.
TYPICAL DAYS/YEAR OF SLUDGE HAULING AS A FUNCTION OF
THE TYPES OF DISPOSAL USED AND GEOGRAPHICAL REGION
Type of Disposal
Landfill or storage
lagoon at disposal site
Agricultural or land
reclamation utilization
Forest land utilization
Dedicated disposal site
Geographical
Region
Northern U.S.
Central U.S.
Sunbelt States
Northern U.S.
Central U.S.
Sunbelt States
Northern U.S.
Central U.S.
Sunbelt States
Northern U.S.
Central U.S.
Sunbelt States
Typical Days/Yr
of Sludge Hauling
230
250
260
100
120
140
160
180
200
160
180
200
A-21.4 Process Design Calculations
A-21.4.1 Annual sludge volume hauled, yd^/yr. Trucks which haul dewa-
tered sludge are sized in terms of yd3 of capacity. Therefore,
it is necessary to convert gal of dewatered sludge to yd3 of
dewatered sludge.
cwrv -
iVl-T -
(365)
387
-------
where
SVCY = Sludge volume hauled, yd3/yr.
SV = Sludge volume, gal /day.
202 = Conversion factor, gal /yd3
A-21.4.2 Number and capacity of sludge haul trucks. Dewatered sl,udge is
hauled in trucks with capacities between 7 and 36 yd-'. The
capacity of the trucks utilized is a function of the volume of
sludge to be hauled per day and the round trip hauling time.
Typical capacities available are 7, 10, 15, 25, and 36 yd .
A-21.4.2.1 Total sludge volume hauled per day.
FACTOR - SVCY (LT + ULT * RTHT)
hAUUK -
where
o
FACTOR = Yd which would have to be hauled per trip if only one truck
were utilized.
A-21.4.2. 2 Capacity and number of haul vehicles. Capacity and
number of haul vehicles are calculated using FACTOR
and the following matrix:
Number, NTR, and Capacity
FACTOR, yd6 of Trucks. CAP, yd3
<7 1 at 7
7 to 10 1 at 10
10 to 15 1 at 15
15 to 25 1 at 25
,25 to 36 1 at 36
36 to 50 2 at 25
50 to 72 2 at 36
If FACTOR exceeds 72 use:
NTR = FA|^OR (Round to next highest integer). CAP - 36 yd3.
where
CAP = Capacity of truck required, yd3.
NTR = Number of trucks required. Calculated from the above matrix,,
A-21.5 Process Design Output Data
A-21.5.1 Annual sludge volume hauled, SVCY, yd3/yr.
A-21.5.2 Capacity of truck, CAP, yd3.
A-21.5.3 Number of trucks required, NTR.
388
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A-21.6 Quantities Calculations
A-21.6.1 Number of round trips/yr.
where
NRT = Number of round trips/yr (round to next highest integer).
A-21.6. 2 Driver time.
DT = [LT + ULT + RTHT] NRT
where
DT = Driver time, hr/yr.
A-21.6. 3 Annual fuel requirement. Vehicle fuel usage is a function of
truck size. The following fuel usage values are typical for
different capacity trucks.
, Fuel Consumption, FC,
Truck Capacity, CAP. ydj _ miles /gal
7 9
10 8
15 7
25 6
36 5
FU = (RTHD) (NRT)
i \*
where
FU = Annual fuel requirement, gal/yr.
FC = Fuel consumption rate, miles/gal, see table above.
A-21.7 Quantities Calculations Output Data
A-21.7.1 Number of round trips/yr, NRT.
A-21.7. 2 Driver labor requirement, DT, hr/yr.
A-21.7. 3 Annual fuel requirement, FU, gal/yr.
389
-------
A-21.8 Unit Price Input Required
A-21.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI, at time cost analysis is made.
A-21.8.2 Current Marshall and Swift Equipment Cost Index, MSECI, at time
cost analysis is made.
A-21.8.3 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-21.8.4 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-21.9 Cost Calculations
A-21.9.1 Cost of sludge haul trucks.
TCOSTTRK = (NTR) (COSTTRK)
where
TCOSTTRK = Total cost of dewatered sludge haul trucks, $.
COSTTRK = Cost per truck, obtained from the table below.
Cost of Truck,
Truck Capacity, CAP, yd6 COSTTRK, 1983 $
7 65,000
10 98,000
15 130,000
25 171,000
36 214,000
A-21.9.2 Cost of vehicle loading facilities. Truck loading facilities
are assumed to consist of a concrete slab, one or more skip
loaders to load the trucks, and miscellaneous improvements such
as drainage, lighting, etc. Cost of the truck loading facili-
ties are assumed to be a function of sludge volume in yd^/yr
(SVCY). The relationship of SVCY to loading area facilities
cost is graduated in a stepped manner and depends upon the num-
ber of loading vehicles required.
COSTLA = (COSTLAB)
where
COSTLA = Total capital cost of loading area facilities, $.
390
-------
COSTLAB = Base cost of loading area facilities, $. This is a
the annual volume of sludge hauled, SVCY, and can
from the table below.
function of
be obtained
Annual Volume of Sludge
Hauled. SVCY. yd3
500 to 2,500
2,500 to 5,000
5,000 to 10,000
10,000 to 20,000
20,000 to 40,000
Base Cost of Loading Area
Facilities. COSTLAB. $
40,000
45,000
50,000
80,000
90,000
Annual Volume of Sludge
Hauled. SVCY, yd*3
40,000 to 60,000
60,000 to 80,000
80,000 to 100,000
100,000 and over
Base Cost of Loading Area
Facilities, COSTLAB, $
100,000
150,000
185,000
220,000
A-21.9.3 Annual vehicle maintenance cost. Maintenance cost per vehicle
mile traveled is a function of truck capacity and initial cost
of the truck. The following factors are used to calculate
vehicle maintenance costs.
Truck Capacity, CAP,
j
7
10
15
25
36
Maintenance Cost, MCM,
$/mi1e Traveled, 1983
0.26
0.32
0.37
0.45
0.53
VMC = (RTHD) (NRT) (MCM)
MSECI
751
where
VMC =
MCM =
Annual maintenance cost, $/yr.
Maintenance cost/mile travelled, $/mile, from table above.
A-21.9.4 Annual maintenance cost for loading area facilities. For the
purposes of this program, it is assumed that loading area faci-
lities annual maintenance cost is a function of loading area
facilities capital cost.
391
-------
MCOSTLA = (COSTLA) (0.05)
where
MCOSTLA = Annual maintenance cost for loading area facilities, $/yr.
0.05 = Assumed annual maintenance cost factor as a function of total
loading area facilities capital cost,
A-21.9,5 Annual cost of operational labor.
COSTLB = (DT) (COSTL) (1.2)
where
COSTLB = Annual cost of operational labor, $/yr.
1.2 = A factor to account for additional labor required at loading
facility.
A-21.9.6 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-21.9.7 Total base capital cost.
TBCC - TCOSTTRK + COSTLA
where
TBCC = Total base capital cost, $.
A-21.9.8 Annual operation and maintenance cost.
COSTOM = (VMC) + (MCOSTLA) + (COSTLB) + (COSTDSL)
where
COSTOM = Total annual operation and maintenance cost, $/yr.
392
-------
A-21.10 Cost Calculation Output Data
A-21.10.1 Total cost of dewatered sludge haul trucks, TCOSTTRK, $.
A-21.10.2 Total capital cost of loading area facilities, COSTLA, $.
A-21.10.3 Annual vehicle maintenance cost, VMC, $/yr.
A-21.10.4 Annual loading facility maintenance cost, MCOSTLA, $/yr.
A-21.10.5 Annual cost of operation labor, COSTLB, $/yr.
A-21.10.6 Annual cost of diesel fuel, COSTDSL, $/yr.
A-21.10.7 Total base capital cost, TBCC, $.
A-21.10.8 Total annual operation and maintenance cost, COSTOM, $/yr.
393
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APPENDIX A-22
LIQUID SLUDGE TRANSPORT BY RAIL
A-22.1 Background
Rail transport of liquid sludge can be a cost-effective and energy-effi-
cient operation. The use of this means of liquid sludge transport is, how-
ever, limited for several reasons, which include:
• The operation requires fixed terminal points. In order to make rail
hauling a truly viable option, generally both the treatment plant and
the disposal site must be located close to the railhead.
• There is an ongoing administrative burden. Because of its more labor
intensive nature and be'cause contractual agreements are made with the
railroad company, a higher administrative cost is associated with a
rail haul operation tha'n with some other forms of sludge transporta-
tion.
• Operations are more vulnerable to labor disputes and strikes.
• There is a potential risk of spills due to the possibility of leaking
valves and derailment.
• In the event of an unforeseen requirement for terminal point reloca-
tion, the choices will be severely limited.
Despite these drawbacks, when geographic and economic conditions are suitable,
the use of rail hauling can be a viable option. However, use of rail trans-
port for-small quantities of sludges or over short distances is not economical
when compared with other transport alternatives.
The physical operation of a liquid sludge rail hauling system is simple.
Liquid sludge is pumped from a storage containment directly into tank cars.
The cars are then transported to the disposal site (or possibly to a receiving
point for another form of transportation) where they are unloaded, usually by
gravity flow. Loading and unloading facilities and labor requirements are
generally provided by the wastewater treatment authority. Tank cars them-
selves and their maintenance are usually contracted for, since the amortiza-
tion on the purchase of a tank car can be at a considerably higher cost than
that of leasing.
Capital costs obtained using the following algorithm include: loading
and unloading rail sidings and switches; site work and buildings at loading
and unloading facilities; and pumps and piping for loading tank cars. Rail
cars are assumed to discharge by gravity into the unloading storage facility.
394
-------
O&M costs include: railroad haul fees; rail tank car lease; facility
operation and maintenance labor; facility operation and maintenance supplies;
electrical energy; and rail maintenance.
A-22.1.1 Algorithm Development
Cost and O&M requirement equations for the following algorithm were
obtained from information presented in Reference 11, pages 21, 50, 52, 60, 61,
and 62. Rail hauling rates for bulk liquids were quoted by the Southern
Pacific Transportation Company. Factors for rate adjustment due to regional
variations included in the algorithm are based on Reference 11, page 68.
A-22.2 Input Data
A-22.2.1 Daily sludge volume, SV, gal /day.
A-22.2. 2 Sludge specific gravity, SSG, unitless.
A-22.2. 3 Round trip haul distance, RTHD, miles.
A-22.3 Design Parameters
A-22.3.1 Daily sludge volume, SV, gal/day. This input value must be
furnished by the user. No default value.
A-22.3. 2 Sludge specific gravity, SSG, unitless. This valuve should be
provided by the user. If not available, default value is cal-
culated with the following equation:
SSG = loo-ss + (ss)
100 (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Assumed sludge solids specific gravity.
A-22.3. 3 Round trip haul distance, RTHD, miles. Typical values range
from 40 to 640 miles. No default value.
A-22.4 Process Design Calculations
A-22.4.1 Wet weight of sludge transported per year.
TS - (SV) (SSG) (8.34) (365)
where
TS = Wet weight of sludge transported per year, tons/yr.
8.34 = Density of water, Ib/gal.
2,000 - Conversion factor, Ib/ton.
395
-------
A-22.4.2 Carloads per year. A standard 20,000-gal capacity railroad
tank car is assumed in the cost estimate.
_ (SV) (365)
" 20,000
where
CLPY = Carloads/yr.
A-22.4.3 Total load and unload time, obtained using the following table:
Daily Sludge Volume, SV Total Load and Unload
(galI/day) Time. TLUT (Hr)
20,500 10
41,000 11
205,500 12
410,000 14
2,055,000 38
where
TLUT = Total load and unload time, hr.
A-22.4.4 Transit time, obtained using the following table:
Transit Time,
RTHD (Miles) TRANST (Hr)
40 96
80 96
160 144
320 168
640 192
where
TRANST = Transit time, hr.
A-22.4.5 Total round trip time.
TRTT - TLUT + TRANST
whe re
TRTT = Total round trip time, hr.
396
-------
A-22.4.6 Number of rail tank cars required.
24)
where
NRTCR = Number of rail tank cars required.
A-22.5 Process Design Output Data
A-22.5.1 Wet weight of sludge transported per year, TS, tons/yr.
A-22.5.2 Carloads per year, CLPY.
A-22.5.3 Total load and unload time, TLUT, hr.
A-22.5.4 Transit time, TRANST, hr.
A-22.5.5 Total round trip time, TRTT, hr,
A-22.5.6 Number of rail tank cars required, NRTCR.
A-22,6 Quantities Calculations
A-22.6.1 Annual operation and maintenance labor requirement, obtained
from the table below:
Daily Sludge Volume, SV Annual Labor Required, L
(gal/day) (hr/yr)
20,500 4,254
41,000 4,384
205,500 9,340
410,000 11,000
2,055,000 29,700
where
L = Operation and maintenance labor requirement, hr/yr.
A-22.6.2 Annual electrical energy requirement, obtained from the table
below:
Daily Sludge Volume, SV Annual Electrical Energy
(gal/day) Requirement, E (kWhr/yr)
20,500 35,000
41,000 40,000
205,500 90,000
410,000 140,000
2,055,000 480,000
397
-------
where
E = Annual electrical energy requirement, kWhr/yr.
A-22.7 Quantities Calculations Output Data
A-22.7.1 Annual operation; and maintenance labor requirement, L, hr/yr.
A-22.7.2 Annual electrical energy requirement, E, kWhr/yr.
A-22.8 Unit Price Input Required
A-22.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-22.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSECI.
A-22.8.3 Region of country, REGION, NC = north central and central, NE =
northeast, SE = southeast, SW = southwest, and WC = west coast.
Default value = NC.
A-22.8.4 Railroad mileage credit (for shipper supplied railroad cars),
RRMC, $/mile. Default value = $0.25/mile (ENRCCI/4,006).
A-22.8.5 Annual full maintenance rail tank car lease rate, ARTCLR, $/yr.
Default = $9,000/yr (ENRCCI/4,006).
A-22.8.6 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-22.8.7 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-22.9 Cost Calculations
A-22.9.1 Railroad facilities construction cost. The facilities include
storage equal toione day's sludge production; loading pumps and
piping sized toifill 1, 2, 10, 20, and 100 unit car trains in
1.5, 2, 3, and 15 hr, respectively; loading and unloading rail
sidings and switches; and loading and unloading buildings and
site work. Costs for storage at the unloading area can be
obtained using algorithms presented in Appendices A-32 through
A-34. Rail cars discharge by gravity into the unloading stor-
age facilities.
398
-------
Railroad facility construction costs are obtained using the
following table:
Total Railroad Facilities
Daily Sludge Volume, SV Construction Cost, CRFCC*
(gal/day) : ($)
20,500 304,000
41,000 341,000
205,500 646,000
410,000 951,000
2,055,000 1,954,000
* 1983 value.
The construction cost should be updated using the Engineering
News Record Construction Cost Index.
TRFCC = (CRFCC) (
where
TRFCC = Railroad facilities construction cost, $.
A-22.9.2 Annual railway haul cost.
A-22.9.2.1 Calculate the point-to-point railroad haul cost.
RRHC =I(TS) (RR) (R FACT)]
where
RRHC = Railroad haul cost, $/yr.
RR = Unadjusted rail rate, $/ton. Rail rates should be
obtained from the following table:
Unadjusted Rail Rate,
Round Trip Haul Distance, RR, $/Ton of Sludge
RTHD (Miles) Hauled
40 3.55
80 5.10
160 6.90
320 11.00
640 21.10
399
-------
RFACT = Regional cost adjustment factor which varies according
to region of the United States. Values should be
obtained from the following:
If REGION - NC, RFACT =1.0
If REGION = NE, RFACT - 1.25
If REGION = SE, RFACT = 0.75
If REGION.- SW, RFACT = 0.90
If REGION = WC, RFACT = 1.10
A-22.9.2.2 Calculate the railroad mileage cost credit (for
shipper supplied railway tank cars).
RRMCC = (RTHD) (CLPY) (RRMC)
where
RRMCC = Railroad mileage cost credit, $/yr.
A-22.9.2.3 Calculate the total rail tank car lease cost.
TRTCLC - (NRTCR) (ARTCLR)
where
TRTCLC = Total rail tank car lease cost, $/yr.
A-22.9.2.4 Calculate the total annual railway haul cost.
TARHC = RRHC - RRMCC + TRTCLC
where
TARHC = Total annual railway haul cost, $/yr.
A-22.9.3 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of labor, $/yr.
400
-------
A-22.9.4 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-22.9.5 Annual operation and maintenance supply cost, obtained from
table below:
Unadjusted O&M
Daily Sludge Volume, SV Supply Cost, QMS
(gal /day) ($/yr)
20,500 800
41,000 1,230
205,500 3,780
410,000 6,140
2,055,000 16,900
COSTMS = (QMS)
where
COSTMS = Annual operation and maintenance supply cost, $/yr.
A-22.9.6 Annual rail maintenance cost, obtained from table below, $/yr.
Unadjusted Rail
Daily Sludge Volume, SV Maintenance Cost, RM
(gal /day) ($/yr)
20,500 2,800
41,000 4,200
205,500 5,600
410,000 11,100
2,055,000 27,800
COSTRM = (RM)
where
COSTRM = Annual rail maintenance cost, $/yr.
401
-------
A-22,9.7 Total facilities operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTMS + COSTRM
where
COSTOM = Total annual facilities operation and maintenance cost, $/yr.
A-22.9.8 Annual railway haul and facilities operation and maintenance
cost.
TARHFOM = TARHC + COSTOM
where
TARHFOM = Annual railway haul and facilities O&M cost, $/yr.
A-22.10 Cost Calculation Output Data
A-22,10.1 Annual railway haul cost, TARHC, $/yr.
A-22.10.2 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-22.10.3 Annual cost of electrical energy, COSTEL, $/yr.
A-22.10.4 Annual operation and maintenance supply cost, COSTMS, $/,yr.
A-22.10.5 Annual rail maintenance cost, COSTRM, $/yr.
A-22.10.6 Total annual facilities operation and maintenance cost, COSTOM,
$/yr.
A-22.10.7 Total base capital cost of railroad facilities, TRFCC, $.
A-22.10.8 Total annual railway haul and facilities O&M cost, TARHFOM,
$/yr.
402
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APPENDIX A-23
BARGE TRANSPORTATION OF LIQUID SLUDGE FOR OCEAN DISPOSAL
A-23.1 Background
The use of self-propelled and/or towed barges for the ocean disposal of
liquid sludge has been practiced for many years. Several considerations are
important in the evaluation of any sludge barge transport system. These in-
clude but are not limited to:
Design and operation of shore facilities.
Design and operation of the barge(s).
Tugboat contracting (when required).
Course, especially when inland waterways must be navigated.
Round trip haul time and distance.
In many cases, particularly when the treatment facility is not located
immediately adjacent to a waterway, sludge storage facilities are required
near the loading dock. Tanks similar in design to unheated digesters are com-
monly used for this purpose. The size of these storage tanks is dependent upon
the sludge generation and handling rates, and an assumed design contingency
factor. Other shore facilities include pumps, piping and docking facilities.
The design and number of barges required for an efficient ocean disposal
operation is highly variable, dependent on such factors as sludge generation
rate, available storage capacity, operating schedule and haul distance. In
general, larger barges can travel at faster speeds and reduce transit times,
thus making them more economical for larger operations. On the other hand,
barges this large may not be practical for smaller treatment plants. A thor-
ough cost analysis, optimizing all variables, should be conducted whenever the
purchase of a barge(s) is contemplated.
Small- and .medium-size treatment plants (e.g., those which generate less
than 2,000 wet tons of sludge annually) generally do not produce enough sludge
to make barge haul/ocean disposal a cost-effective alternative. However, cer-
tain municipalities on the east coast (i.e., New York and New Jersey) combine
sludges through inter-facility pumping for storage at a common site, or
through transporter-arranged multiple pickups of sludge along the disposal
route. In this way, smaller treatment plants achieve lower costs through eco-
nomy of scale.
For many treatment plants, full-service contracts for barge hauling ser-
vices are the most cost-effective option. If, however, a treatment plant does
utilize its own barge(s), tugboat services are usually contracted. Because of
high capital and maintenence costs, only very large plants generally own the
motive power unit(s) (tugboat or power barge). For purposes of this algo-
rithm, it is assumed that barges are owned and tug services are contracted.
403
-------
Capital costs obtained using this cost algorithm include the following:
• Purchase of one or more, barges.
• Construction of barge loading and docking facility (includes sludge
storage). •
• Purchase and installation of sludge pumps and piping needed to fill
barges.
Annual operation and maintenance costs consist of the following:
§ Tugboat rental.
* Barge maintenance.
t Barge loading and sludge storage facility operation and maintenance.
• Annual incidental costs for permits, monitoring, and administration,
A-23.1.1 Algorithm Development
The following algorithm was developed from information on barge transpor-
tation of sludge presented in Reference 11, pages 14, 15, 18, 19, 35, 36, 37,
38, 45, 46, 48, 49, 60, and 61. Supporting information was provided from a
draft ocean disposal model developed by the Scientex Corporation for EPA.
Current values for barge costs, capacities, and fuel requirements supplied by
manufacturers were also used.
A-23.2 Input Data
A-23.2.1 Daily sludge volume, SV, gal/day.
A-23.2.2 Round trip barge hauling distance, RTHD, miles.
A-23.2.3 Average barge speed, BRSP, mph.
A-23.2.4 Barge downtime per trip for loading, docking, idle time, etc.,
DT, hr/trip.
A-23.2.5 Days of separate sludge storage required at loading facility,
STDAYS, days.
A-23.2.6 Hours required to fill barge at loading facility, FILLHRS, hr.
A-23.3 Design Parameters
A-23.3.1 Daily sludge volume, SV, gal/day. This input value must be
furnished by the user. No default value.
A-23.3.2 Roundtrip haul distance, RTHD, miles. This input value must be
furnished by the user, and should include the distance covered
while actually releasing sludge to the ocean.
A-23.3.3 Average barge speed, BRSP, mph. Range of barge speed is ap-
proximately 2 to 10 mph. Default value = 3 mph.
404
-------
A-23.3.4 Barge downtime per trip for loading, docking, idle time, etc.,
DT, hr/trip. Default value = 8 hr/trip.
A-23.3.5 Days of separate sludge storage required at loading facility,
STDAYS, days. Default value = 2 days.
A-23.3.6 Hours required to fill barge at loading facility, FILLHRS, hr.
Default value = 4 hr.
A-23.4 Process Design Calculations
A-23,4.1 Calculate annual sludge weight, liquid tons/yr.
TT (SV) x (365) x (8.6)
I, (2,000)
where
TT = Total quantity of, sludge barged, liquid tons/yr.
8.6 = Assumed weight of sludge, Ib/gal (based on sludge specific
gravity of 1.03).
2,000 = Conversion factor, Ib/ton.
A-23.4. 2 Calculate barge hours per trip.
HOURS = -n + DT
where
HOURS = Barge hr/trip.
A-23.4. 3 Calculate required barge capacity, BRCAP.
• (365) (24) (0.8)
where
BRCAP = Total barge capacity required, tons, assuming year-around,
24-hr/day operation.
365 = Days/yr.
24 = Hr/day.
0.8 = Utilization factor.
405
-------
A-23.4.4 Calculate barge size and number required, using table below.
Standard barge sizes range from 1,500 to 7,500 ton capacity.
Required Barge Barge Size Number of Barges
Capacity, BRCAP, tons BRSIZE, tons NBR
0 - 1,500 1,500 1
1,501 - 3,000 3,000 1
3,001 - 4,500 4,500 1
4,501 - 6,000 6,000 1
6,001 - 7,500 7,500 1
7,501 - 9,000 . 4,500 2
9,001 - 12,000 6,000 2
12,001 - 15,000 7,500 2
15,001 - 18,000 6,000 3
18,001 - 22,500 7,500 3
where
BRSIZE = Barge size required, tons.
NBR = Number of barges required.
A-23.4.5 Calculate barge trjips per year.
TP = TT
BRSTZE
where
TP = Number of trips annually.
A-23.4.6 Calculate annual tugboat time required
TUGTIME = (TP)
JUfallMt -
where -
TUGTIME = Annual hours of tugboat use.
A-23.4.7 Calculate volume of liquid sludge tanks at barge loading facil
ity.
STVOL = (SV) (STDAYS)
406
-------
where
STVOL = Volume of liquid sludge storage tanks at barge loading facility,
gal.
A-23.4.8 Calculate capacity of pumps and piping to fill barge(s).
PlIMPIN - (NBR) (BRSIZE) (233)
rvmrin (60) (FILLHRS)
t
where
PUMPIN = Capacity of loading pumps and piping, gal/min.
233 = Gal of sludge/liquid ton, assuming a sludge specific gravity of
1.03.
60 = Conversion factor, min/hr.
A-23.4.9 Calculate size of loading dock in terms of number of barges to
be docked simultaneously.
. DOCK = NBR
where
DOCK = Size of dock in terms of number of barges.
A-23.5 Process Design Output Data
A-23.5.1 Annual sludge weight, TT, liquid tons/yr.
A-23.5.2 Barge hours per trip, HOURS.
A-23.5.3 Total barge capacity required, BRCAP, tons.
A-23.5.4 Size of each barge, BRSIZE, liquid tons.
A-23.5.5 Number of barges required, NBR.
A-23.5.6 Annual number of barge trips, TP, number/yr.
A-23.5.7 Annual tugboat time required, TUGTIME, hr/yr.
A-23.5.8 Volume of liquid sludge storage tanks, STVOL, gal.
A-23.5.9 Capacity of pumps and pipes to fill barge(s), PUMPIN, gal/min.
A-23.5.10 Size of loading dock, DOCK, in terms of number of barges.
407
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A-23.6 Unit Price Input Required
A-23.6.1 Current Engineering News Record Construction Cost Index,
ENRCCI, at time cost analysis is prepared.
A-23.6.2 Current Marshall and Swift Equipment Cost Index, MSECI, at time
cost analysis is prepared.
A-23.6.3 Cost of 3,000 liquid ton capacity barge, BRCOST, $. Default
value = $1,950,000 (MSECI/751).
A-23.6.4 Cost of sludge storage tanks, STCOST, $/gal. Default value =
$0.40/gal storage capacity (ENRCCI/4,006).
A-23.6.5 Cost of sludge pumps and piping to fill barge(s), PUMPCOST,
$/gal/min. Default value = $160/gal/min (ENRCCI/4,006).
A-23.6.6 Cost of docking* facilities for barge(s), DOCKCOST, $/barge.
Default value = $500,000 (ENRCCI/4,006).
A-23.6.7 Cost of tugboat; rental, TUGCOSTHR, $/hr. Default value =
$350/hr (MSECI/751).
i
A-23.7 Cost Calculations
A-23.7.1 Total barge capital cost. Capital cost of barges is calculated
based on the capital cost of a 3,000-liquid-ton-capacity barge.
BRSIZE °'6
TBRCOST = (BRCOST) (NBR) j~j^
where
TBRCOST = Total barge capital cost, $.
0.6 = Constant reflecting economy of scale for various size barges.
A-23.7.2 Total barge loading and sludge storage facilities capital cost.
FACCOST = [(STVOL) (STCOST)] + [(PUMPIN) (PUMPCOST)] + [(DOCK) (DOCKCOST)]
where
FACCOST = Total capital cost of barge loading and sludge storage facili-
ties, $.
A-23.7.3 Annual tugboat rental cost
TUSCOST = (TUGTIME) (TUGCOSTHR)
408
-------
where
'-//
TUGCOST = Tugboat rental cost, $/yr.
A-23.7.4 Annual barge maintenance cost.
BROMCOST = TBRCOST (0.12)
where
BROMCOST = Annual barge maintenance cost, $/yr.
0.12 = Annual O&M cost as a percentage of barge capital cost.
A-23.7.5 Annual barge loading and sludge storage facilities operation
and maintenance cost.
FACOMCOST = FACCOST (0.10)
where
FACOMCOST = Annual barge facilities operation and maintenance cost, $/yr.
0.10 = Annual O&M cost as a percentage of barge facilities capital
cost.
A-23.7.6 Annual incidental costs for permits, monitoring, and adminis-
tration.
INCCOST = TT (0.22)
where
INCCOST = Annual incidental costs, $/yr
0.22 = Cost/liquid ton for incidental costs, $/ton.
A-23.7.7 Total base capital cost.
TBCC = TBRCOST + FACCOST
where
TBCC = Total base capital cost, $.
409
-------
A-23.7.8 Annual operation and maintenance cost
COSTOM = TUGCOST + BROMCOST + FACOMCOST + INCCOST
where
COSTOM = Total annual O&M cost, $/yr.
A-23.8 Cost Calculations Output Data
A-23.8.1 Total barge capital cost, TBRCOST, $.
A-23.8.2 Total barge loading and sludge storage facilities capital cost,
FACCOST, $. ;
A-23.8.3 Annual tugboat rental cost, TUGCOST, $/yr.
A-23.8.4 Annual barge maintenance cost, BROMCOST, $/yr.
A-23.8.5 Annual barge facility operation and maintenance cost,
FACOMCOST, $/yr.
A-23.8.6 Annual permit, monitoring, and administration cost, INCCOST,
$/yp.
A-23.8.7 Total base capital cost, TBCC, $.
A-23.8.8 Total annual operation and maintenance cost, COSTOM, $/yr.
410
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APPENDIX A-24
LONG-DISTANCE PIPELINE TRANSPORT OF LIQUID SLUDGE
A-24.1 Background
Pipelines have been successfully used for transporting liquid sludge
(i.e., usually less than 10 percent solids by weight), from very short dis-
tances up to distances of 10 miles or more. Liquid sludge pumping through
pipelines is generally best accomplished with sludge containing 3 percent sol-
ids or less.
The principles applied in liquid sludge pipeline and water pipeline
design are quite similar. Unlike water, however, laminar flow is common in
sludges with higher solids concentrations. Also, there is a tendency for the
organic sludge solids to adhere to the inside of pipelines during pumping.
These conditions often result in friction losses that are higher than those
experienced in water pipelines. In the following alogorithm, this phenomenon
has been taken into account by applying a "K" factor to an otherwise unmodi-
fied Hazen-Williams formula. This "K" factor, which is a function of both
sludge solids content and sludge type, is discussed in more detail in Sub-
section A-24.3.4. Pipelines with coated interiors (e.g., glass or cement mor-
tar linings) are often used as a means of reducing friction loss. Because
dried sludge can "cake" on interior pipe walls, flushing pipelines with clean
water or treated effluent is also commonly practiced as means of reducing
friction loss due to such "caking." In addition, flushing has been used as a
means for preventing sludge solids from settling and hardening in dormant
pipelines.
Cost considerations for this algorithm include: pipeline and pumping
station construction costs and O&M labor, materials, and energy requirements.
Large variations in construction costs are associated with certain route-
specific variables such as the number of river crossings or the fraction of
pipeline length requiring excavation of rock. In order to obtain the best
results, the user is encouraged to obtain or plot a viable pipeline route on a
suitable scale map and input the most accurate design parameter values possi-
ble. Cost of right-of-way acquisition is not included in this algorithm.
A-24.1.1 Algorithm Development
The following algorithm is based on common engineering principles used
when designing a pipeline transport system. Sources of information on sludge
pipeline transport were Reference 4, pages 14-1 through 14-2, and Reference 8,
pages 41 through 46. Cost equations are based on Reference 11, pages 24, 54
through 58, and 69 through 71; and Reference 12, pages 4-1 through 4-28.
411
-------
A-24.2 Input Data
A-24.2.1 Daily sludge volume, SV, gpd.
A-24.2.2 Pipeline length, PL, ft.
A-24.2.3 Hazen-Williams friction coefficient, C.
A-24.2.4 Coefficient to adjust for increased head loss due to sludge
solids content, K.
A-24.2.5 Elevation at the start of the pipeline, PSELEV, ft.
A-24.2.6 Maximum elevation in the pipeline, ELEVMX, ft.
A-24.2.7 Hours per day of pumping, HPD, hr.
A-24.2.8 Fraction of pipeline length that requires rock excavation,
ROCK.
A-24.2.9 Fraction of pipeline length that does not involve rock excava-
tion, but is greater than 6 ft deep, DEPTH.
A-24.3 Design Parameters
A-24.3.1 Pipeline velocity is 3 ft/sec maximum.
A-24.3.2 Pipeline friction loss, PFL, function of pipe diameter, velo-
city, and "C" value selected.
A-24.3.3 Hazen-Williams friction coefficient, C. Default value = 90.
A-24.3.4 Coefficient, K, to adjust for increased head loss due to sludge
solids content. No default value. Pipeline friction losses
may be much higher for transporting sewage sludge than for
transporting water, depending upon such factors as the sludge
concentration (percent solids by weight) and the type of sludge
(raw primary, digested, etc.). The user is cautioned that the
K factors provided in the table below are highly simplified and
may give inaccurate results for pipeline friction loss. An
elaborate method for design engineering calculations is pro-
vided in Section 14.1.2 of Reference 4.
412
-------
K FACTORS FOR VARIOUS SLUDGE CONCENTRATIONS
AND TWO TYPES OF SLUDGE
K Factor
Digested
SI udge
1.05
1.10
1.25
1.45
1.65
1.85
2.10
2.60
Untreated Primary
SI udge
1.20
1.60
2.10
2.70
3.40
4.30
5.70
7.20
Solids Concentration
Percent by Weight
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
A-24.3.5 Number of 2- or 4-1 ane highway crossings, NOH. Default value =
1.
A-24.3.6 Number of divided highway crossings, NODH. Default value = 0.
A-24.3.7 Number of railroad tracks (2 rails/track) crossed, NRC.
Defaul t val ue = 2.
A-24.3.8 Number of small rivers crossed, NOSR. Default value = 0.
A-24.3.9 Number of large rivers crossed, NOLR. Default value = 0.
A-24.4 Process Design Calculations
A-24.4.1 Calculate pipeline diameter.
1/2
PD = 12
r sv i
[ 63,448 (HPD)J
(Round to next highest even integer.)
where
PD = Pipeline diameter, inches.
63,488 = Conversion factor =
3.1416 [ (3 ft/sec) (7.48 gal/ft3) (86.400 sec/day)
4 [ (24 hr/day)
Note: Pipeline is assumed to be flowing full.
413
-------
A-24.4.2 Calculate head loss due to pipeline friction.
1.852
PFL = K
SV (24)
i •) CO
(HPD) (PDr*D
-------
where
NOPS = Number of pumping stations.
HAVAIL = Head available from each pumping station, ft. This is a func-
tion of the type of pump, sludge flow rate, and whether or not
pumps are placed in series. Obtain this value from the table
below.
Pipe Diameter, PD Head Available,
(Inches) HAVAIL (Ft)
4 & 6 450
8 260
10 & 12 230
14 & 16 210
18 & 20 200
A-24.4.6 Total horsepower required for pump stations,
up (H) (SV) (33.000)
™ ~ (HPD) (60) (0.50) (8.34)
where
HP = Total pumping horsepower required, hp.
33,000 = Conversion factor, hp to ft-lb/min.
60 = Conversion factor, min/hr.
0.50 = Assumed pump efficiency.
8.34 = Density of water, Ib/gal.
A-24.4.7 Horsepower required per pump station.
HP
HPS =
NOPS
where
HPS = Horsepower required per pump station, hp.
A-24.5 Process Design Output Data
A-24.5.1 Pipe diameter, PD, inches.
A-24.5.2 Head loss due to pipe friction, PFL, ft/ft of pipe.
A-24.5.3 Head required due to elevation change, HELEV, ft.
A-24.5.4 Total pumping head required, H, ft.
415
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A-24.5.5 Number of pumping stations, NOPS,
A-24.5.6 Total pumping horsepower required, HP, hp.
A-24.5.7 Horsepower required per pump station, HPS, hp.
A-24.6 Quantities Calculations
A-24.6.1 Electrical energy requirement.
c [(0.0003766)' (1.2) (H) 1 (SV) (365) (8.34)
h = |j(0.5) (0.9) J 17UOO
where
E = Electrical energy, kWhr/yr.
0.0003766 = Conversion factor, kWhr/1,000 ft-lb.
8.34 = Density of water, Ib/gal.
1.2 = Assumed specific gravity of sludge.
0.5 = Assumed pump efficiency.
0.9 = Assumed motor efficiency.
A-24.6.2 Operation and maintenance labor requirement.
L = (NOPS) (IPS) + (PL) (0.02)
where
L = Annual operation and, maintenance labor, hr/yr.
0.02 = Assumed maintenance hr/yr per ft of pipeline, hr/ft.
IPS = Annual labor per pump station, hr/yr. This is a function of pump
station horse power,; HPS, as shown below.
I
Pump Station Annual O&M Labor,
Horsepower, HPS LPS (Hr)
25 700
50 720
75 780
100 820
150 840
200 870
250 910
300 940
350 980
416
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A-24.7 Quantities Calculations Output Data
A-24.7.1 Electrical energy requirement, E, kWhr/yr.
A-24.7.2 Operation and maintenance labor requirement, L, hr/yr.
A-24.8 Unit Price Input Required
A-24.8.1 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-24.8.2 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-24.8.3 Unit cost of electricity, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-24.8.4 Unit cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-24.9 Cost Calculations
A-24.9.1 Cost of installed pipeline.
COSTPL = (1 + 0.7 ROCK) (1 + 0.15 DEPTH) PL (COSTP)
where
COSTPL = Cost of installed pipeline, $.
0.7 = Assumed fraction of pipeline length that requires rock excava-
tion.
0.15 = Assumed fraction of pipeline length that does not require rock
excavation, but is greater than 6 ft deep.
COSTP = Pipeline cost per unit length, $/ft. This cost is obtained
from the following table.
Pipeline'Diameter, PD Installed Cost, COSTP,
(Inches) ($/ft. 1983)
4 21.10
6 22.80
8 25.30
10 27.90
12 30.40
14 35.50
16 38.90
18 43.10
20 50.70
417
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A-24.9.2 Cost of pipeline crossings.
COSTPC - [NQH (19,000) t NODH (38,000) + NRC (14,000)
+ NOSR (85,000) + NOLR ($340,000)]
where
COSTPC = Cost of pipe crossings, $.
A-24.9.3 Cost of pump stations.
COSTPS = NOPS [165,000 + 2,700 (HPS-25)]
where
COSTPS = Construction cost of all pump stations.
Note: If HPS is less than 25 hp, then, for this calculation, let HPS
25 hp,
A-24.9.4 Annual cost of electrical energy.
COSTEL - (E) (COSTE)
where
COSTEL = Total annual cost of electricity, $/yr.
A-24.9.5 Annual cost of operation and maintenance labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-24.9.6 Cost of pumping station replacement parts and materials.
COSTPM a NOPS (PS) (
418
-------
where
COSTPM = Annual cost of pumping station replacement parts and materials,
$/yr.
PS =Annual cost of parts and supplies for a single pumping station,
$/yr. This cost is a function of pumping station horse power as
. shown below.
Pump Station Annual Parts and Supplies
Horsepower, HPS Cost, PS, ($/Yr)
25 1,080
50 1,130
75 1,270
100 1,380
150 1,500
200 1,590
250 2,840
300 2,960
350 3,110
A-24.9.7 Total base capital cost.
TBCC = COSTPL + COSTPC + COSTPS
where
TBCC = Total base capital cost, $.
A-24.9.8 Total annual operation and maintenance cost.
COSTOM = COSTEL + COSTLB + COSTPM
where
COSTOM = Total annual operation and maintenance cost, $/yr,
A-24.10 Cost Calculations Output Data
A-24.10.1 Cost of installed pipeline, COSTPL, $.
A-24.10.2 Cost of pipeline crossings, COSTPC, $.
A-24.10.3 Cost of pump stations, COSTPS, $.
A-24.10.4 Annual cost of electrical energy, COSTEL, $/yr.
419
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A-24.10.5 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-24.10.6 Cost of pumping station replacement parts and materials,
COSTPM, $/yr.
A-24.10.7 Total base capital cost, TBCC, $.
A-24.10.8 Annual operation and maintenance cost, COSTOM, $/yr.
420
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APPENDIX A-25
OCEAN OUTFALL DISPOSAL
A-25.1 Background
Ocean outfalls provide a means for both transportation and disposal of
sludge, but are of limited applicability for most facilities, since they re-
quire close proximity to the ocean. In addition, regulatory constraints limit
their use as a method of sludge disposal.
Ocean disposal of liquid sludge is typically accomplished using a pipe-
line and outfall system identical to that used for ocean disposal of waste-
water. A manifold or multiple-point diffuser is commonly employed at the end
of the outfall pipeline to facilitate the dilution of the liquid sludge with
seawater. In virtually all ocean outfalls, only one pump station is required
unless the onshore pipeline length is excessive. The ocean outfall system
presented in this algorithm consists of one pump station, both land and sub-
marine pipelines, and a diffuser section at the point of discharge. If a long
overland pipeline is necessary to carry sludge to the beginning of the coastal
outfall, the user should use the "Long Distance Pipeline Transport of Liquid
Sludge" algorithm (Appendix A-24) to calculate the cost of this pipeline.
Pipeline design is broken down into three different types of construction
environments: onshore pipeline, nearshore pipeline, and offshore pipeline.
Costs used for these three types vary due to the differing materials used and
degrees of difficulty associated with pipeline construction in each environ-
ment.
Capital costs for ocean outfalls vary over a wide range, depending on
site-specific conditions. The use of this algorithm will provide only a very
rough estimate of costs. Cost considerations for the operation and mainte-
nance of an ocean outfall system basically consist of pump power (electrical)
requirements and pump and pipeline maintenance requirements.
A-25.1.1 Algorithm Development
Design equations in the following algorithm were developed using common
engineering principles applicable to the design of a pipeline transport sys-
tem. However, construction and O&M costs are significantly higher than pipe-
line transport costs due to the conditions under which construction and main-
tenance occur. Cost curves were developed using the following unpublished
documents by R. L. Michel of EPA: Evaluation of Ocean Outfall Cost Data (Jan-
uary 5, 1982); Order of Magnitude Equations for Estimating Costs of Ocean Out-
falls (January 26, 1982); and Ocean Outfall Cost Factors (March 17, 1982).
421
-------
A-25.2 Input Data
A-25.2.1 Daily sludge volume, SV, gal/day.
A-25.2.2 Hours per day of pumping, HPD, hr.
i
A-25.2.3 Hazen-Williams friction coefficient, C.
A-25.2.4 Coefficient to adjust for increased head loss due to sludge
solids content, K.
A-25.2.5 Onshore pipeline length, ONPL, ft.
A-25.2.6 Offshore (past the!surf zone) pipeline length, OFPL, ft.
A-25.2.7 Nearshore (in the surf zone) pipeline length, NSPL, ft.
A-25.2.8 Diffuser pipeline length, NDPL, ft.
A-25.3 Design Parameters
A-25.3.1 Daily sludge volume, SV, gal/day. This input value must be
furnished by the user. No default value.
A-25.3.2 Hours per day of pumping, HPD, hr. Default value = 20 hr,,
I
A-25.3.3 Hazen-Williams friction coefficient, C. Default value = 90.
A-25.3.4 Coefficient, K, to adjust for increased head loss due to sludge
solids content. No default value. Pipeline friction losses
may be much higher for transporting sewage sludge than for
transporting water, depending upon such factors as the sludge
concentration (percent solids by weight) and the type of sludge
(raw primary, digested, etc.). The user is cautioned that the
K factors provided in the table below are highly simplified and
may give inaccurate results for pipeline friction loss. An
elaborate method for design engineering calculations is pro-
vided in Section 14.1.2 of Reference 4.
K FACTORS FOR VARIOUS SLUDGE CONCENTRATIONS
AND TWO TYPES OF SLUDGE
K Factor
Solids Concentration
Percent by Weight
1.0
2.0
3.0
4.0
5.0
Digested
Sludge
1.05
1.10
1.25
1.45
1.65
Untreated Primary
Sludge
1.20
1.60
2.10
2.70
3.40
422
-------
K Factor
Solids Concentration Digested Untreated Primary
Percent by Height SIudge SIudge
6.0 1.85 4.30
7.0 2.10 5.70
8.0 2.60 7.20
A-25.3.5 Onshore pipeline length, ONPL, ft. No default value.
A-25.3.6 Offshore pipel ine 1 ength, OFPL, ft. No default value.
A-25.3.7 Nearshore pipeline length, NSPL, ft. No default value.
A-25.3.8 Diffuser pipeline length, NDPL, ft. No default value.
A-25.3.9 Pipeline velocity is 3 ft/sec maximum for all segments (i.e.,
onshore, nearshore, offshore, and diffuser).
A-25.3.10 Pipeline friction loss is a function of pipe diameter in all
segments (i.e., onshore, nearshore, offshore, and diffuser).
A-25.3.11 Head due to elevation difference is assumed to be negligible;
therefore, equal to zero.
A-25.4 Process Design Calculations
A-25.4.1 Calculate minimum pipeline diameter, based on flow velocity of
3 ft/sec.
r sv 10.5
PD = 12 I 63,448 (HPD)
where !
PD = Pipeline diameter, inches.
63,448 = Conversion factor =
f 3 1
3.1416 (3 ft/sec) (7.48 gal/ft f (86,400 sec/day)
4 [ 24 hr/day J
Increase PD to next largest standard pipe diameter of 6 inches or more
(i.e., 6, 8, 10, 12, 15, 18, 21, 24, 27, 30, 36, 42, or 48 inches).
A-25.4.2 Calculate head loss due to pipe friction per foot of pipeline
length.
~ 1.852
PFL = K
(HPD) PD£'°° (C) (405)
423
-------
A-25.4.3 Calculate total pipeline length, TPL, ft.
TPL = ONPL + OFPL + NSPL + NDPL
where
TPL ~ Total pipeline length, ft.
A-25.5 Process Design Output Data
A-25.5.1 Pipe diameter, PD, inches.
A-25.5.2 Head!oss due to pipe friction, PFL, feet per foot of pipe,
A-25.5.3 Total pipeline length, TPL, ft.
A-25.6 Quantities Calculations
A-25.6.1 Annual electrical energy requirement.
E -[ (0*0003766) (1.2) (TPL) (PFL)I (SV) (365) (8.34)
~[~ (0.5). (0.9) J (1,000)
where
E = Annual electrical energy requirement, kWhr/yr.
0.0003766 = Conversion factor, kWhr/1,000 ft-lb.
1,2 = Assumed specific gravity of sludge.
8.34 = Density of water, Ib/gal.
0.5 = Assumed pump efficiency.
0.9 = Assumed motor efficiency.
A-25.6.2 Annual operation and maintenance labor requirement.
L = (TPL) (0.077) + (LPS)
where
L = Annual operation and maintenance labor, hr/yr.
0.077 = Assumed maintenance hr/yr per ft of pipeline.
LPS = Pump station operation and maintenance labor, hr.
424
-------
This is a function of pumping station capacity as shown following:
Pump Station Annual O&M
Capacity (gal/day) Labor, IPS (hr)
180,000 700
400,000 720
720,000 780
1,160,'OOQ 820
1,580,000 840
2,020,000 870
2,880,000 910
3,600,000 940
4,320,000 980
A-25.7 Quantities Calculation Output Data
A-25.7.1 Annual electrical energy requirement, E, kWhr/yr
A-25.7.2 Annual operation and maintenance labor requirement, L, hr/yr.
A-25.8 Unit Price Input Required
A-25.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI. No default value.
A-25.8.2 Unit cost of electricity, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-25.8.3 Unit cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-25.9 Cost Calculations
A-25.9.1 Total installed cost of pipeline.
A-25.9.1.1 Cost of onshore pipeline.
COSTONPL = ONPL (COSTONP)
where
COSTONPL = Cost of installed onshore pipeline, $.
COSTONP =0nshore pipeline cost unit per length, $/ft. This
cost is obtained from the table presented below.
425
-------
Onshore Pipeline
Pipe Diameter Installed Cost,
(inches) COSTONP ($/ft)
6 22.80
8 25.30
10 27.90
12 38.90
16 50.70
20 67.40
24 89.60
30 119.20
36 158.50
42 210.80
48 280.40
54 372.90
A-25.9.1.2 Cost:of offshore pipeline.
COSTOFPL = OFPL (COSTOFP) (
where
COSTOFPL = Cost of installed offshore pipeline, $.
OFPL = Offshore pipeline length, ft.
COSTOFP = Offshore pipeline per cost unit length, $/ft. This
cost is obtained from the following table:
Offshore Pipeline
Pipe Diameter Installed Cost,
(inches) COSTOFP ($/ft)
6 324
8 326
10 329
12 333
16 342
20 . 354
24 369
30 396
36 429
42 468
48 513
54 564
426
-------
A-25.9.1.3 Cost of nearshore pipeline
COSTNSPL = NSPL (COSTNSP)
where
COSTNSPL = Cost of installed nearshore (surf zone) pipeline, $.
COSTNSP - Nearshore pipeline cost per unit length, $/ft. This
cost; is obtained from the following table:
Nearshore Pipeline
Pipe Diameter Installed Cost,
(inches) COSTNSP ($/ft)
6 567
8 686
10 795
12 898
16 1,084
20 1,256
24 1,420
30 1,640
36 1,850
42 2,050
48 2,240
54 2,420
A-25.9.1.4 Cost of diffuser pipeline.
COSTNDPL - NDPL (COSTNDP) (
where
COSTNDPL = Cost of installed diffuser pipeline, $.
NDPL = Diffuser pipeline length, ft.
COSTNDP = Diffuser pipeline cost per unit length, $/ft. This
cost is obtained from the table presented below.
427
-------
Dlffuser Pipeline
Pipe Diameter Installed Cost,
(inches) COSTNDP ($/ft)
6 404
8 406
10 409
12 413
16 422
20 434
24 449
30 476
36 509
42 548
48 593
54 644
A-25.9.1.5 Total cost of outfall pipeline.
TCOSTPL = COSTONPL + COSTOFPL + COSTNSPL + COSTNDPL
where
TCOSTPL = Total installed cost of outfall pipeline, $.
A-25.9.2 Cost of pump station.
COSTPS = COSTIPS (4
ENRCCL
where
COSTPS = Construction cost of pump station, $.
COSTIPS - Cost of individual pump station, $, as obtained from the fol
lowing table:
Pump Station
Pump Station Construction Cost,
Capacity (gpd) COSTIPS ($)
180,000 80,000
400,000 96,300
720,000 120,000
1,160,000 149,000
1,580,000 183,000
2,020,000 208,000
2,880,000 260,000
3,600,000 313,000
4,320,000 365,000
428
-------
A-25.9.3 Annual cost of electrical energy required.
COSTEL = E (COSTE)
where
COSTEL = Total annual cost of electricity, $/yr.
A-25.9.4 Annual cost of operation and maintenance labor.
CO'STLB = I (COSTL)
where
COSTLB = Total cost of operation and maintenance labor, $/yr.
A-25.9.5 Annual cost of pumping station parts and materials,
'ENRCCI'
COSTPM - PS
where
COSTPM = Annual cost of pumping station parts and materials, $/yr.
PS =Annual cost of parts and supplies for a single pumping station,
$/yr. This cost is a function of pumping station capacity as
shown in the following table:
Pump Station Annual Parts and
Capacity (gal/day) Material, PS ($/yr)
180,000 1,080
400,000 1,130
720,000 1,270
1,160,000 1,380
1,580,'QOO 1,500
2,020,000 1,590
2,880,000 2,840
3,600,000 2,960
4,320,000 3,110
A-25.9.6 Total base capital cost.
TBCC = TCOSTPL + COSTPS
429
-------
where
TBCC = Total base capital cost, $.
A-25.9.7 Total annual operation and maintenance cost.
COSTOM = COSTEL + COSTLB + COSTPM
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-25.10 Cost Calculations Output Data
A-25.10.1 Total installed cost of outfall pipeline, TCQSTPL, $.
A-25.10.2 Cost of pump station, COSTPS, $.
A-25.10.3 Annual cost of electrical energy, COSTEL, $/yr.
A-25.10.4 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-25.10.5 Annual cost of pumping station parts and materials, COSTPM,
$/yr.
A-25.10.6 Total base capital cost, TBCC, $.
A-25.10.7 Total annual operation and maintenance cost, COSTOM, $/yr.
430
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APPENDIX A-26
LAND APPLICATION TO CROPLAND
A-26.1 Background
Use of municipal wastewater treatment plant sludge as a source of fertil-
izer nutrient to enhance crop production is widespread in the United States.
Hundreds of communities, both large and small, have developed successful agri-
cultural utilization programs. These programs benefit the municipality gener-
ating the sludge by providing an environmentally acceptable means of sludge
disposal, while providing the participating farmer with a substitute or sup-
plement for conventional fertilizers.
A major advantage of agricultural utilization is that the municipality
usually does not have to purchase land. Furthermore, the land utilized for
sludge application is kept in production, and its value for future uses is not
impaired.
Sludge application rates for agricultural utilization (dry unit weight of
sludge applied per unit of land area per year) are usually low, i.e., in the
range of 3 to 10 tons/acre/year, depending on the physical characteristics of
the sludge and soil and the types of crops grown. Sludges can be applied by
surface spreading or subsurface injection. Surface application methods
include spreading by specially equipped farm tractors, tank wagons, special
applicator vehicles equipped with flotation tires, tank trucks, and portable
or fixed irrigation systems.
Sludge is usually applied only once a year to each application site.
Relatively large land areas may thus be needed, requiring the cooperation of
many individual land owners. In addition, the scheduling of sludge transport
and application around agricultural planting, harvesting, etc., plus adverse
climatic conditions, may require careful management. If the farms accepting
sludge are numerous and widespread, an expensive and complicated sludge dis-
tribution system may be required.
It is important to note that this cost algorithm assumes that the sludge
application vehicles at the application site are not the same vehicles which
transported the sludge from the treatment plant to the application site. In
many cases, however, the same vehicle is used to both transport the sludge and
apply it to the application site. If the same vehicle is used for sludge
transport and application, then the user should use zero for the cost of the
on-site sludge application vehicle, COSTPV (Subsection A-26.8.6), since the
cost of that vehicle has already been included in the previous sludge hauling
process.
431
-------
The user should note that this cost al gorlthm does include calculations
for the costs of land, lime addition, and site grading. In many cases of
agricultural sludge utilization, 'all or some of these costs are not applicable
to the municipality, since they, are either unnecessary or paid for by the
farmer. If so, the user of this unit process cost algorithm simply uses zero
cost, where appropriate, in Subsections A-26.8.1, A-26.8.2, and A-26.8.5.
Q&M costs include labor, diesel for the operation of vehicles, vehicle
maintenance, and site maintenance.
A-26.1.1 Al gorithm Development
Capital costs and O&M requirements in this algorithm were based on infor-
mation obtained from equipment, manufacturers. Additional information was
obtained from Reference 13, pages 6-1 through 6-46.
A-26.2 Input Data
A-26.2.1 Daily sludge volume, SV, gpd.
A-26.2.2 Sludge suspended solids concentration, SS, percent.
A-26.2.3 Sludge specific gravity, SSG, unitless.
A-26.2.4 Average dry solids application rate, DSAR, tons of dry solids/
acre/yr.
A-26.2.5 Annual sludge application period, DPY, days/yr.
A-26.2.6 Daily sludge application period, HPD, hr/day.
A-26.2.7 Fraction of farmland area needed in addition to actual sludge
application area, e.g., buffer zones, unsuitable soil or ter-
rain, changes in cropping patterns, etc., FWWAB.
A-26.2.8 Fraction of food chain crop growing area requiring lime addi-
tion to raise pH to 6.5, FRPH.
A-26.2.9 Fraction of food bhain crop growing area requiring light grad-
ing for drainage control , FRLG.
A-26.3 Design Parameters
A-26.3.1 Daily sludge volume, SV, gpd. This input value must be pro-
vided by the user,; No default value.
A-26.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
432
-------
A-26.3.3 Sludge specific gravity, SSG, unit! ess. This value should be
provided by the user. If not provided, default value is cal-
culated using the following equation:
SSG = 100 - SS (SS) ~~
100 (1.42) (100)
where
SSG = Sludge specific gravity, unit! ess.
1.42 = Assumed specific gravity of sludge solids, unit!ess.
A-26.3.4 Average dry solids application rate, DSAR, tons of dry solids/
acre/yr. This value normally ranges from 3 to 10 for typical
food chain crop growing sites depending upon crop grown, soil
conditions, climate, and other factors. Default value = 5
tons/acre/yr.
A-26.3.5 Annual sludge application period, DPY, days/yr. This value
normally ranges from 100 to 140 days/yr depending upon climate,
cropping patterns, and other factors. See table below for
typical values. Default value = 120 days/yr.
TYPICAL DAYS PER YEAR OF FOOD CHAIN CROP SLUDGE APPLICATION
Typical Days/Yr
Geographi c Regi on of SI udge Appi i cation
Northern U.S. 100
Central U.S. 120
Sunbelt States 140
A-26.3.6 Daily sludge application period, HPD, hr/day. This value nor-
mally ranges from 5 to 7 hr/day depending upon equipment used,
proximity of application sites, and other factors. Default
value = 6 hr/day.
A-26,3.7 Fraction of farmland area needed in addition to actual sludge
application area, e.g., buffer zones, unsuitable soil or ter-
rain, changes in cropping patterns, etc., FWWAB. Default value
= 0.4.
A-26.3.8 Fraction of food chain crop growing area requiring lime addi-
tion to raise pH to 6.5, FRPH, Depending upon the natural pH
of local soils, this fraction can vary from 0 to 1. Default
val ue = 0. 5.
433
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A-26.3.9 Fraction of food chain crop growing area requiring light grad-
ing for drainage icontrol, FRLG. Depending upon local condi-
tions at the sludge application sites this fraction can vary
from 0 to 1. Default value = 0.3.
A-26.4 Process Design Calculations
A-26.4.1 Calculate dry solids applied to land per year.
= (SV) (8.34) (SS) (SSG) (365)
;2>6(
(2,000) (100)
where
TDSS = Dry solids applied to land, tons/yr.
8.34 = Density of water, Ib/gal.
2,000 = Conversion factor, Ib/ton.
A-26.4.2 Sludge application area required.
'TDSS)
SOAR =
DSAR
where
SOAR = Farm area required for sludge application, acres.
A-26.4.3 Hourly sludge application rate.
new - (SV) (365)
Hbv " (DRY) (HPD)
where
HSV = Hourly sludge application rate, gal/hr.
A-26^4.4 Capacity of on-site mobile sludge application vehicles. It is
assumed that the sludge has already been transported to the
private farm sludge application sites by a process such as a
large haul vehicle, etc. The on-site mobile application vehi-
cles accept the sludge from the transport vehicle, pipeline, or
on-site storage facility, and proceed to the sludge application
area to apply the sludge. Typical on-site mobile sludge appli-
cation vehicles at farm sites have capacities ranging from
1,600 to 4,000 gal:, in the following increments: 1,600, 2,200,
3,200, and 4,000 gal.
A-26.4.4.1 Capacity and number of on-site mobile sludge appli-
cation vehicles. The capacity and number of on-
site mobile sludge application vehicles required is
determined by comparing the hourly sludge volume,
HSV, with the vehicle sludge handling rate, VHRCAP.
See table below.
434
-------
Vehicle Number of Each Capacity, NOV
Capacity CAP (Gal)
HSV (Gal/Hr) 1,600 2,200 3,200 4,000
0 - 3,456 1 -
3,456 - 4,243 - 1
4,243 - 5,574 - 1
5,574 - 6,545 - 1
6,545 - 8,500 - 2
8,500 - 11,200 - 2
11,200 - 13,100 - 2
13,100 - 19,600 - - 3
19,600 - 26,000 - 4
Above 26,000 gal/hr, the number of 4,000-gal capacity vehicles
required is calculated by:
HSV
NOV = ^g (round to the next highest integer)
where
NOV = Number of on-site sludge application vehicles.
A-26. 4. 4. 2 Average round trip on-site cycle time for mobile
sludge application vehicles.
CT _ (IT) + (ULT) + (TT)
U« / D
where
CT = Average round trip on-site cycle time for mobile sludge
application vehicle, min.
LT = Load time, min, varies with vehicle size (see table
below).
ULT = Unload time, min, varies with vehicle size (see table
below).
TT = On-site travel time to and from sludge loading facility
to sludge application area, min (assumed values are
shown in table below).
0.75 = An efficiency factor.
435
-------
Vehicle
Capacity, CAP
(Sal)
1,600
2,200
3,200
4,000
LT
. (Min)
6
7
8
9
ULT
(Min)
8
9
10
11
TT
(Min)
5
5
5
5
CT
(Min
25
28
31
33
A-26. 4. 4. 3 Single vehicle sludge handling rate. The actual
hourly sludge throughput rates for an on-site
mobile sludge application vehicle is dependent upon
the vehicle tank capacity, the cycle time, and an
efficiency factor.
VHRCAP =
where
VHRCAP = Single vehicle sludge handling rate, gal/hr.
CAP = Vehicle tank capacity, gal.
0. 9 = Efficiency factor.
The table below shows VHRCAP values for typical size vehicles.
Vehicle Capacity, VHRCAP
CAP (Gal ) (Gal/Hr)
1,600 3,456
2,200 4,243
3,200 5,574
4,000 6,545
A-26. 5 Process Design Output Data
A-26. 5.1 Dry solids applied to land, TDSS, tons/yr.
A-26. 5.2 Sludge applicatioh area required, SOAR, acres.
A-26. 5. 3 Hourly sludge application rate, HSV, gal/hr.
A-26. 5.4 Capacity of on-site mobile sludge application vehicle, CAP,
gal .
A-26. 5. 5 Number of on-site mobil e sludge application vehicles, NOV.
A-26. 5. 6 Cycle time for on-site mobile sludge application vehicle, CT,
min.
436
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A-26.5.7 Single vehicle sludge handling rate, VHRCAP, gal/hr.
A-26.6 Quantities Calculations
A-26.6.1 Total land area required. For virtually all sludge to food
chain crop applications, a larger land area is required than
that needed only for sludge application/disposal (SOAR). The
additional area may be required for changes in cropping pat-
terns, buffer zones, on-site storage, wasted land due to
unsuitable soil or terrain, and/or land available in the event
of unforeseen future circumstances. In any case, the addi-
tional land area required is site specific and varies signifi-
cantly, e.g., from 10 to 100 percent of the SOAR.
TLAR .- (1 + FWWAB) (SOAR)
where
TLAR = Total land area required for food chain application site, acres.
A-26.6.2 Lime addition required for soil pH adjustment to a value of at
1 east 6.5.
TLAPH = (FRPH) (SOAR)
where
TLAPH - Total land area requiring lime addition, acres.
A-26.6.3 Light grading required. Typical agricultural land used for
growing food chain crops is usually already graded to even
slopes. However, when sludge is added to the soil, additional
1 ight grading may be necessary to improve drainage control and
minimize runoff of sludge solids. Obviously, this need is site
specific.
TLARLS = (FRLS) (SOAR)
where
TLARLS = Total land area requiring light grading, acres.
A-26.6.4 Annual operation labor requirement.
i 8 (NOV) (DPY)
•077
437
-------
where
L = Annual operation labor requirement, hr/yr.
8 = Hr/day assumed.
0.7 = Efficiency factor.
A-26.6.5 Annual diesel fuel requirement for on-site mobile sludge appli-
cation vehicles.
P,, = (HSV) (HPD) (DPY) (DFRCAP)
(VHRCAP)
where
FU = Annual diesel fuel usage, gal/yr.
DFRCAP = Diesel fuel consumption rate (gal/hr); for specific capacity
vehicle, see table below.
GALLONS OF FUEL PER HOUR FOR VARIOUS CAPACITY
SLUDGE APPLICATION VEHICLES
Vehicle Capacity, DFRCAP
CAP (Gal) (Gal/Hr)
1,600 3.5
2,200 4
3,200 5
4,000 6
A-26.7 Quantities Calculations Output Data
A-26.7.1 Total land area required, TLAR, acres.
A-26.7.2 Total land area requiring lime addition, TLAPH, acres.
A-26.7.3 Total land area requiring light grading, TLARLG, acres.
A-26.7.4 Annual operation labor required, L, hr/yr.
A-26.7.5 Annual diesel fuel :usage, FU, gal/yr.
A-26.8 Unit Price Input Required
A-26.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-26.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
" sis is made, MSEC I.;
438
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A-26.8.3 Cost of land, LANDCST, $/acre. Default value = zero. It is
assumed that application of sludge is to privately owned farm
land.
A-26.8.4 Cost of lime addition, PHCST, $/acre. Default value = $60/acre
(ENRCCI/4,006); assumes 2 tons of lime/acre requirement.
A-26.8.5 Cost of light grading earthwork, LGEWCST, $/acre. Default
value = $l,000/acre (ENRCCI/4,006).
A-26.8.6 Cost of on-site mobile sludge application vehicle, COSTPV, $.
A-26.8.7 Cost of operation 1 abor, COSTL, $/hr. Default value =
$13.00/hr (ENRCCI/4,006).
A-26.8.8 Cost of diesel fuel, COSTDF, $/gal. Default value »
$1.30/gal (ENRCCI/4,006).
A-26.9 Cost Calculations
A-26.9.1 Cost of land.
COSTLAND = (TLAR) (LANDCST)
where
COSTLAND = Cost of land, $.
A-26.9.2 Cost of lime addition to adjust pH of soil.
COSTPHT =(TLAPH) (PHCST)
where
COSTPHT = Cost of lime addition, $.
A-26.9.3 Cost of light grading earthwork.
COSTEW = (TLARLG) (LGEWCST)
where
COSTEW = Cost of earthwork grading., $.
A-26.9.4 Cost of on-site mobile sludge application vehicles. Note: If
same vehicle is used both to transport sludge to the site and
to apply sludge to the land, then COSTMAV = zero.
439
-------
COSTMAV = (NOV) (COSTPV)
where
COSTMAV = Cost of on-site mobile sludge application vehicles, $.
COSTPV = Cost/vehicle, obtained from the table below.
COST OF ON-SITE MOBILE SLUDGE APPLICATION VEHICLES (1983)
Vehicle Capacity, Cost Per Vehicle,
CAP (Gal) , COSTPV (1983 $)
1,600 85,000
2,200 95,000
3,200 120,000
4,000 140,000
A -26. 9.5 Annual cost of operation labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation labor, $/yr.
A-26.9. 6 Annual cost of diesel fuel.
COSTOSL = (FU) (COSTOF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-26.9. 7 Annual cost of maintenance for on-site mobile sludge applica-
tion vehicl es.
- r(HSV) (HPD) (DPY) (MCSTCAP)-i MS EC I
- Lx J ~75T~
where
VMC = Annual cost of vehicle maintenance, $/yr.
MCSTCAP - Maintenance cost, $/hr of operation; for specific capacity of
vehicle, see table below.
440
-------
HOURLY MAINTENANCE COST FOR VARIOUS CAPACITIES OF SLUDGE
APPLICATION VEHICLES
Vehicle Capacity, Maintenance Cost, MCSTCAP
CAP (Gal) ($/Hr)
1,600 . 4.85
2,200 5.31
3,200 5.96
4,000 7.16
A-26.9.8 Annual cost of maintenance for land application site (other
than vehicles) including monitoring, recordkeeping, etc.
SMC = [(TLAR) (12)] ENRCCI
4,006
where
SMC = Annual cost of maintenance (other than vehicles), $/yr.
12 = Annual maintenance cost, $/acre.
A-26.9.9 Total base capital cost.
TBCC = COSTLAN0 + COSTPHT + COSTEW + COSTMAV
where
TBCC = Total base capital cost, $.
A-26.9.10 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTDSL + VMC -+ SMC
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-26.10 Cost Calculations Output Data
A-26.10.1 Cost of land for sludge application site, COSTLAND, $.
A-26.10.2 Cost of lime addition for pH adjustment, COSTPHT, $.
A-26.10.3 Cost of light grading earthwork, COSTEW, $.
A-26.10.4 Cost of on-site mobile sludge application vehicles, COSTMAV, $.
441
-------
A-26.10.5 Annual cost of operation labor, COSTLB, $/yr.
A-26.10.6 Annual cost of diesel fuel, COSTDSL, $/yr,
A-26.10.7 Annual cost of vehicle maintenance, VMC, $/yr.
A-26,10.8 Annual cost of site maintenance, SMC, $/yr.
A-26.10.9 Total base capital cost of sludge to cropland program using on-
site mobile sludge application vehicles, TBCC, $.
A-26.10.10 Base annual operation and maintenance cost for sludge to crop-
land program using on-site mobile sludge application vehicles,
COSTOM, $/yr.
442
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APPENDIX A-27
LAND APPLICATION TO NON-FOOD CHAIN CROPS
(OTHER THAN FOREST LAND)
A-27.1 Background
In terms of cost of sludge transport, storage, and application, there
appears to be little difference between costs for land application to non-food
chain crops (other than forest land) and land application to food chain crops.
Therefore, the user is directed to either the cost algorithm for land applica-
tion to food chain crops (Appendix A-26) or land application to forest land
(Appendix A-29), as appropriate, along with the selected sludge transport and
si udge treatment processes requi red.
Non-food chain crops are those crops which are not directly or indirectly
consumed by humans. Examples of such crops are cotton used for fiber, horti-
cultural specialization, ornamental floriculture, turf grasses, flax, and seed
production. Note that tobacco and animal fodder are considered food chain
crops. Also included among non-food chain crops are timber land, tree farms,
and other non-food tree growing operations; these are covered under a separate
process algorithm entitled, "Land Application to Forest Land Sites" (Appendix
A-29).
One difference between application of sewage sludge to non-food chain
crops is that it may be easier to obtain public acceptance and regulatory
agency approval for a program of sludge application to non-food chain crops.
There will be less concern for the potential contamination of crops by heavy
metal buildup and/or pathogens.
A second potential difference between application of sewage sludge to
non-food chain crops and food chain crops is that it may be possible to apply
sludge with higher metal content for a longer period of years to certain non-
food chain crops without adversely affecting plant health (e.g., avoiding
phytotoxic conditions). This potential difference, however, is plant species-
specific, and it is beyond the scope of this cost model to evaluate such site-
and crop-specific variations.
In summary, for cost purposes, there appears to be little tangible dif-
ference between land application of sludge to food chain crops and non-food
chain crops (other than forest land), so no separate cost algorithm is pro-
vided for non-food chain crops (other than forest land).
443
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APPENDIX A-28
SLUDGE APPLICATION TO'MARGINAL LAND FOR LAND RECLAMATION
A-28.1 Background
The application of municipal sewage sludge to disturbed or marginal land
to enhance land reclamation has been successfully demonstrated in Pennsylvania
and other states. The city of-Philadelphia applies most of its sludge (as
compost) to the reclamation of mining lands in Pennsylvania.
Sludge application for land reclamation is usually a one-time applica-
tion, i.e., sludge is not applied again to the same land area at periodic
intervals in the future.Where this is true,the project must have a continu-
ous supply of new disturbed land upon which to apply sludge in future years.
This additional disturbed land,can be created by ongoing mining or mineral
processing operations, or may consist of presently existing large areas of
disturbed land which are gradually reclaimed. In either case, an arrangement
is necessary with the land owner to allow for future sludge application
throughout the life of the sludge application project. For this reason, this
cost algorithm does not generate the total land area required as do the other
land application cost algorithms, but instead generates the annual 1 and area
requi red.
This cost algorithm estimates only the cost of sludge application at the
reclamation site using on-site sludge application vehicles. It is assumed
that the sludge is transported to the site by one of the transportation pro-
cesses that appears in this manual (transportation algorithms are provided in
Appendices A-20 through A-25). Typically, the on-site sludge application
vehicles will obtain sludge from a large "nurse" truck, or an interim on-site
sludge storage facility. However, if the same truck is used to both haul and
apply the si udge, do not add the cost of on-site appl ication trucks. ("COSTMAV
"in Secti on A-28.9.5 of thi s al gori thin equal s zero,)
i
Sludge application rates (dry tons/acre) for reclaiming disturbed or mar-
ginal land vary widely depending on such factors as sludge characteristics,
soil characteristics, environmental considerations (principally the need for
ground water protection), and the type of vegetative cover planned. Investi-
gation is required to determine the acceptable sludge application rate for a
specific site(s). Application rates ranging from 10 to 180 dry tons/acre are
reported in the literature, but rates less than 100 dry tons/acre are more
common. ;
Disturbed or marginal lands often require extensive grading, soil pH
adjustment by lime addition, scarifying, and vegetation seeding. Usually, the
land owner pays for the cost of these operations. However, there are provi-
sions for including these costs in the cost algorithm, if desired.
444
-------
A-28.1.1 Al gorithm Devel opment
Concepts for sludge application in this algorithm are based on Reference
13, pages 8-1 through 8-24. Fuel, labor, and capital costs were derived from
information supplied by equipment manufacturers and from Reference 14, pages
60 through 61 and pages 86 through 87.
A-28.2 Input Data
A-28.2.1 Daily sludge volume, SV, gpd.
A-28.2.2 Sludge suspended solids concentration, SS, percent.
A-28.2.3 Sludge specific gravity, SSG, unit! ess.
A-28.2.4 Average dry solids application rate, DSAR, tons of dry solids/
acre. In reclaiming marginal land, sludge is typically only
applied once, not annually as is done with other land appli-
cation methods.
A-28.2.5 Annual sludge application period, DRY, days/yr.
A-28.2.6 Daily sludge application period, HPD, hr/day.
A-28.2.7 Fraction of land reclamation site area used for purposes other
than sludge application, e.g., buffer zone, internal roads,
sludge storage, waste land, etc., FWWAB.
A-28.2.8 Fraction of land reclamation site area requiring addition of
lime for adjustment of soil pH to a value of 6.5, FRPH.
A-28.2.9 Fraction of land area requiring light grading, FRLG.
A-28.2.10 Fraction of land requiring medium grading, FRMG.
A-28.2.11 Fraction of land requiring extensive grading, FREG.
A-28.3 Design Parameters
A-28.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-28.3.2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-28.3.3 Sludge specific gravity, SSG, unitless. This value should be
provided by the user. If not provided, default value is calcu-
lated using the following equation:
SSG =
100 - SS (SS)
100 (1.42) (100)
445
-------
where
SSG = Sludge specific gravity
1.42 = Assumed sludge solids specific gravity.
A-28.3.4 Average dry solids application rate, DSAR, tons of dry solids/
acre. This value normally ranges from 10 to 100 for typical
land reclamation sites depending upon sludge quality, soil con-
ditions, and other factors. Default value = 25 tons/acre.
A-28.3.5 Annual sludge application period, DRY, days/yr. This value
normally ranges from 100 to 180 days/yr for land reclamation
sites depending upon climate, soil conditions, planting sea-
sons, and other factors. Default value = 140 days/yr.
A-28.3,6 Daily sludge application period, HPD, hr/day. This value nor-
mally ranges from 5 to 8 hr/day depending upon equipment used,
site size, and other factors. Default value = 7 hr/day.
A-28.3.7 Fraction of land; reclamation site area used for purposes other
than sludge application, FWWAB. Varies significantly depending
upon site specific conditions. Default value = 0.3 for land
reclamation sites.
A-28.3.8 Fraction of land reclamation site area requiring addition of
lime to raise soil pH to value of 6.5, FRPH. Typically, strip
mining spoils have a low soil pH, and substantial lime addition
may be required; Default value = 1.0 for land reclamation
sites.
A-28.3.9 Fraction of land reclamation site requiring light grading,
FRLS. Varies significantly depending upon site specific condi-
tions. Default value = 0.1.
A-28.3.10 Fraction of land reclamation site requiring medium grading,
FRMS. Varies significantly depending upon site specific condi-
tions. Default value = 0.3.
A-28.3.11 Fraction of land reclamation site requiring extensive grading,
FREG. Varies significantly depending upon site specific condi-
tions. Typically, a land reclamation site requires significant
heavy grading. Default value = 0.6.
A-28.4 Process Design Calculations
A-28.4.1 Calculate dry solids applied to land per year.
TDSS - (SV1 (8.34) (S3) (SSG) (365)
1 ^ " (2,000) (100)
where
TOSS = Dry solids applied to land, tons/yr.
446
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A-28.4.2 Sludge disposal area required, not including area which is used
for purposes other than sludge disposal, e.g., buffer zone,
roads, waste area, etc. Since sludge is typically applied only
once to marginal land for reclamation purposes, the sludge dis-
posal area required represents the annual new land area which
must be 1 ocated each year.
where
SOAR = Site area required only for sludge disposal, acres/yr.
A-28.4.3 Hourly sludge application rate.
....
DRY) (HPD)
where
HSV = Hourly sludge application rate, gal/hr.
A -28. 4. 4 Capacity of on-site mobile sludge application vehicles. It is
assumed that the sludge has already been transported to the
land reclamation site by a
haul vehicle. The on-site
the sludge from a transport
age facility, and proceed
apply the sludge. Typical
vehicles at land reclamation
1,600 to 4,000 gal, in
3,200, and 4,000 gal.
previous unit process, e.g., large
mobile application vehicles accept
vehicle, pipeline, or on-site stor-
to the sludge application area to
on-site mobile sludge application
sites have capacities ranging from
the following increments: 1,600, 2,200,
A-28.4.4.1 Capacity and number of on-site mobile sludge appli-
cation vehicles. The capacity and number of on-
site mobile sludge application vehicles required is
determined by comparing the hourly sludge volume,
HSV, with the vehicle sludge handling rate, VHRCAP.
See tab! e be! ow.
HSV (Gal/Hr)
0 -
3,456 -
4,243 -
5,574 -
6,545 -
3,456
4,243
5,574
6,545
8,500
8,500 - 11,200
Vehicle Number of Each Capacity, NOV
Capacity, Gal, CAP
1,600
2,200
1
2
447
3,200
1
2
4,000
-------
Vehicle Number of Each Capacity, NOV
Capacity, Gal, CAP
HSV (Gal/Hr) 1,600 2.200 3,200 4,000
11,200 - 13,100 - - - 2
13,100 - 19,600 3
19,600 - 26,000 4
Above 26,000 gal/hr, the number of 4,000-gal capacity vehicles
is calcul a ted by:
ucu
NOV = ipo'd- (roun<* to the next highest integer)
where
NOV = Number of on-site sludge application vehicles.
A-28. 4. 4. 2 Average round trip on-site cycle time for mobile
sludge application vehicles.
- (IT) * (ULT) * (TT)
^_.
where
CT = Average round trip on-site cycle time for mobile sludge
application vehicle, min.
LT = Load time, min, varies with vehicle size (see table
below).
ULT = Unload time, min, varies with vehicle size (see table
be! ow) .
TT = On-site travel time to and from sludge loading facility
to sludge application area, min (assumed values are
shown i n tabl e be! ow) .
0.75 = An efficency factor.
Vehicle
Capacity
(Gal)
1,600
2,200
3,200
4,000
LT
(Min)
6
7
8
9
ULT
(Min)
8
9
10
11
TT
(Min)
5
5
5
5
CT
(Min)
25
28
31
33
448
-------
A-28. 4. 4. 3 Single vehicle sludge handling rate. The actual
hourly sludge throughput rates for an on-site
mobile sludge application vehicle is dependent upon
the vehicle tank capacity, the cycle time, and an
efficiency factor.
VHRCAP -
where
VHRCAP = Single vehicle sludge handling rate, gal/hr.
CAP = Vehicle tank capacity, gal.
CT = Cycle time, min.
0.9 = Efficiency factor.
The table below shows VHRCAP values for typical size vehicles.
Vehicle Capacity VHRCAP
(Gal) (Gal/Hr)
1,600 3,456
2,200 4,243
3,200 5,574
4,000 6,545
A-28. 5 Process Design Output Data
A-28. 5.1 Dry solids applied to land, TOSS, tons/yr.
A-28. 5. 2 Sludge disposal area required, SOAR, acres/yr.
A-28. 5. 3 Hourly sludge application rate, HSV, gal/hr.
A-28. 5.4 Capacity of on-site mobile sludge application vehicle, CAP,
gal .
A-28.5.5 Number of on-site mobile sludge application vehicles, NOV.
A-28. 5.6 Cycle tiflie for On-site mobile sludge application vehicle, CT,
min.
A-28.5.7 Single vehicle sludge handling rate, VHRCAP, gal/hr.
A-28. 6 Quantities Calculations
A-28. 6.1 Total land area required per year. For virtually all land rec-
lamation sites a larger land area is required than that needed
only for sludge application/disposal (SOAR). The additional
area may be required for buffer zones, on-site roads, on-site
storage, wasted land due to unsuitable terrain, etc. In any
case, the additional land area required for land reclamation
449
-------
sites is usually not significant, since they are typically
located far from population centers.
TLAR = (1 + FWWAB) (SOAR)
where
TLAR = Total land area required for land reclamation sites, acres/yr.
A-28.6.2 Lime addition required for soil pH adjustment to a value of pH
= 6.5.
TLAPH = (FRPH) (SOAR)
where
TLAPH
A-28.6.3
Total land area which must have lime applied for pH control,
acres/yr.
Earthwork required. Usually a potential land reclamation site
will require extensive grading to smooth out contours, provide
drainage control ,\ etc. The extent of grading required is very
site specific, and can represent a significant portion of the
total site preparation cost when the terrain is rough.
TLARLG = (FRLG) (TLAR)
TLARMG = (FRMG) (TLAR)
TLAREG = (FREG) (TLAR)
where
TLARL'G = Total land area requiring light grading, acres/yr.
TLARMG = Total land area requiring medium grading, acres/yr.
TLAREG = Total land area requiring extensive grading, acres/yr.
A-28.6.4 Number of monitoring wells required. Virtually all regulatory
agencies require that ground water quality monitoring wells be
installed as a condition of land reclamation site permitting.
The number and depth of monitoring wells required varies as a
function of site'size, ground water conditions, and regulatory
agency requirements. In this algorithm, it is assumed that
even the smallest land reclamation site must have one ground
water quality monitoring well, and one additional monitoring
well for each 200 acres/yr of total site area (TLAR) above 50
acres/yr.
NOMWR = 1 + ^TLAj?Qo" 5° (increase to next highest integer)
450
-------
where
NOMWR = Number of monitoring wells required/yr.
A-28.6.5 Operation labor requirement.
[_' = 8 (NOV) (DPY)
where
L = Operation labor requirement, hr/yr.
8 = Hr/day assumed, hr.
0.7 = Efficiency factor.
A-28.6.6 Diesel fuel requirements for on-site mobile sludge application
vehicles.
Ftl - (HSV) (HPD) (DPY) (DFRCAP)
(VHRCAP)
where
FU = Diesel fuel usage, gal/yr.
DFRCAP = Diesel fuel consumption rate for certain capacity vehicle, see
table below, gal/hr.
GALLONS OF FUEL PER HOUR FOR VARIOUS CAPACITY
SLUDGE APPLICATION VEHICLES
Vehicle Capacity (CAP), Gal DFRCAP, Gal/Hr
1,600 3.5
2,200 4
3,200 5
4,000 6
A-28.7 Quantities Calculations Output Data
A-28.7.1 Total land area required, TLAR, acres/yr.
A-28.7.2 Total land area which must have lime added for soil pH adjust-
ment, TLAPH, acres/yr.
A-28.7.3 Total land area requiring light grading, TLARLG, acres/yr.
A-28.7.4 Total land area requiring medium grading, TLARMG, acres/yr.
A-28.7.5 Total land area requiring extensive grading, TLAREG, acres/yr.
451
-------
A-28.7.6 Number of monitoring wells required per year, NOMWR.
A-28.7.7 Annual operation labor requirement, L, hr/yr.
A-28.7.8 Annual diesel fuel usage, FU, gal/yr.
A-28.8 Unit Price Input Required
A-28.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-28.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-28.8.3 Cost of land, LANDCST, $/acre. Typically, the land used for
reclamation is not purchased by the municipality. Default
value = zero.
A-28.8.4 Cost of lime addition, PHCST, $/acre. Default value =
$120/acre (ENRCCI/4,006), based on 4 tons of lime/acre.
A-28.8.5 Cost of light grading earthwork, LGEWCST, $/acre. Default
value = $l,000/acre (ENRCCI/4,006).
A-28.8.6 Cost of medium grading earthwork, MGEWCST, $/acre. Default
value = $2,000/acre (ENRCCI/4,006).
A-28.8.7 Cost of extensive grading earthwork, EGEWCST, $/acre. Default
value = $5,000/acre (ENRCCI/4,006).
A-28.8.8 Cost of monitoring well, MWCST, $/well. Default value = $5,000
(ENRCCI/4,006).
A-28.8.9 Cost of operational labor, COSTL, $/hr. Default value =
$13.00/hr (ENRCCI/4,006).
A-28.8.10 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006). ;
A-28.9 Cost Calculations
A-28.9.1 Annual cost of land.
COSTLAND = (TLAR) (LANDCST)
where
COSTLAND = Annual cost of land for land reclamation site, $/yr.
A-28.9.2 Annual cost of lime addition to adjust pH of the soil.
COSTPHT = (TLAPH) (PHCST)
452
-------
where
COSTPHT = Annual cost of lime addition for pH adjustment, $/yr.
A-28.9.3 Annual cost of grading earthwork.
COSTEW = (TLARLG) (LGEWCST) + (TLARMG) (MGEWCST) + (TLAREG) (EGEWCST)
where
COSTEW = Cost of earthwork grading, $/yr.
A-28.9.4 Annual cost of monitoring wells.
COSTMW = (NOMWR) (MWCST)
where
COSTMW = Cost of monitoring wells, $/yr.
A-28.9.5 Cost of on-site mobile sludge application vehicles.
COSTMAV = C(NOV) (COSTPV)]
where
COSTMAV = Cost of on-site mobile sludge application vehicles, $.
COSTPV = Cost/vehicle, obtained from the table below.
COST OF ON-SITE MOBILE SLUDGE APPLICATION VEHICLES (1983)
Vehicle Capacity. Gal COSTPV. 1983 $
1,600 85,000
2,200. 95,000
3,200 120,000
4,000 . 140,000
A-28.9.6 Annual cost of operation labor.
COSTLB = (L) (COSTL)
453
-------
where
COSTLB - Annual cost of operation labor, $/yr.
COSTL = Cost of labor, $/hr.
A -28. 9. 7 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-28.9.8 Annual cost of maintenance of on-site mobile sludge application
vehicles.
I
vwr - r(HSV) (HPD) (DPY) (MCSTCAP)! NSECI
VPK, - L- (VHRCAP) J 751
where
VMC = Annual cost of vehicle maintenance, $/yr.
MCSTCAP = Maintenance cost, $/hr of operation; for specific capacity of
vehicle, see table below.
HOURLY MAINTENANCE COST FOR VARIOUS CAPACITIES OF SLUDGE
APPLICATION VEHICLES
Vehicle Capacity, Gal MCSTCAP. $/Hr
1,600 4.85
2,200 5.31
3,200 5.96
4,000 7.16
A-28.9.9 Annual cost of maintenance of land reclamation site (other than
vehicles) for monitoring, recordkeeping, etc.
SMC - C(TLAR)
where
SMC = Annual cost of land reclamation site maintenance (other than
vehicles), $/yr.
12 = Annual maintenance cost, $/acre.
454
-------
A-28.9.10 Total base capital cost.
^ TBCC - COSTMAV
where
TBCC = Total base capital cost, $.
A-28.9.11 Total annual operation, maintenance, land, and earthwork cost.
COSTOM = COSTLB + COSTDSL + VMC + SMC + COSTLAND + COSTPHT + COSTEW + COSTMW
where
COSTOM = Annual operation, maintenance, land, and earthwork cost, $/yr.
A-28.10 Cost Calculations Output Data
A-28.10.1 Annual cost of land for reclamation site, COSTLAND, $/yr.
A-28.10.2 Annual cost of lime addition for pH adjustment, COSTPHT, $/yr.
A-28.10.3 Annual cost of grading earthwork, COSTEW, $/yr.
A-28.10.4 Annual cost of monitoring wells, COSTMW, $/yr.
A-28.10.5 Cost of on-site mobile sludge application vehicles, COSTMAV, $.
A-28.10.6 Annual cost of operation labor, COSTLB, $/yr.
A-28.10.7 Annual cost of diesel fuel, COSTDSL, $/yr.
A-28.10.8 Annual cost of vehicle maintenance, VMC, $/yr.
A-28.10.9 Annual cost of site maintenance, SMC, $/yr.
A-28.10.10 Total base capital cost of land reclamation sites using on-site
mobile sludge application vehicles, TBCC, $.
A-28.10.11 Total annual operation, maintenance, land, and earthwork cost
for land reclamation site using on-site mobile sludge applica-
tion vehicles, COSTOM, $/yr.
455
-------
APPENDIX A-29
LAND APPLICATION TO FOREST LAND SITES
A-29.1 Background
The application of municipal sewage sludge to forest land has been suc-
cessfully demonstrated in the states of Washington, Michigan, and South Caro-
lina. The city of Seattle is beginning a full-scale program. Commercial tim-
ber and fiber production lands, as well as federal and state forests, are
potential application sites for properly managed programs.
This cost algorithm estimates only the cost of sludge application at the
forest site using specially designed on-site liquid sludge application vehi-
cles. It is assumed that the sludge is transported to the site by one of the
transportation processes appearing in Appendices A-20 through A-25. Typi-
cally, the on-site liquid sludge application vehicles will obtain sludge from
a large "nurse" truck, or an on-site sludge storage facility.
Sludge application rates (dry tons/acre) for forest land vary widely,
depending on such factors as sludge characteristics, tree maturity, tree spe-
cies, soil characteristics, etc.; Investigation is required to determine the
acceptable sludge application rate for a specific site. Unlike cropland
application which usually involves annual sludge application, forest land
sludge application to a specific site is often done at multi-year intervals,
e.g., every 5 years.
Forest land sites are usually less accessible to sludge application vehi-
cles than cropland, and on-site clearing and grading of access roads is often
an initial capital cost. Provisions for estimating the cost of clearing brush
and trees and grading rough access roads are included in this cost algorithm.
These costs are often paid by the land owner.
This cost algorithm assumes that liquid sludge is applied by means of
specially designed tanker trucks equipped with a spray "cannon" having a range
of approximately 100 ft. :
While provision is made in the cost algorithm for including land costs,
the municipality generally will not purchase or lease the application site,
and land cost will be zero.
Base capital costs include ;(where appropriate) the cost of land, clearing
brush and trees, grading, monitoring wells, and mobile sludge application
vehicles. Base annual O&M costs include labor, diesel fuel for vehicles,
vehicle maintenance, and site maintenance.
456
-------
A-29.1.1 Al gorithm Devel opment
i
Information utilized in the process design calculations for this algo-
rithm was derived from Reference 13, pages 7-1 through 7-20, and Reference
15. Cost equations are based on Reference 14, pages 60, 61, 86, and 87; Ref-
erence 15; and information supplied by equipment manufacturers.
A-29.2 Input Data
A-29.2.1 Daily sludge volume, SV, gpd.
A-29.2.2 Sludge suspended solids concentration, SS, percent.
A-29.2.3 Sludge specific gravity, SSG, unitless.
A-29.2.4 Average dry solids application rate, DSAR, tons of dry solids/
acre.
A-29.2.5 Annual sludge application period, DRY, days/yr.
A-29.2.6 Daily sludge application period, HPD, hr/day.
A-29.2.7 Frequency of sludge application to forest land at dry solids
application rate, i.e., period between application of sludge to
same forest land area, FR, yr.
A-29.2.8 Fraction of forest 1 and site area used for purposes other than
sludge application, e.g., buffer zone, internal roads, sludge
storage, waste land, etc., FWWAB.
A-29.2.9 Fraction of forest land site area requiring clearing of brush
and trees to allow access by application vehicle, FWB.
A-29.2.10 Fraction of land area requiring grading of access roads to
allow travel by sludge application vehicle, FR6.
A-29.3 Design Parameters
A-29.3.1 Daily sludge volume, SV, gpd. This input value must be pro-
vided by the user. No default value.
A-29.3.2 Sludge suspended sol ids concentration, SS, percent. This input
value must be provided by the user. No default value.
SSG = IPO - ss (ss)
100 (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Assumed sludge sol ids specific gravity.
457
-------
A-29.3.4 Average dry solids application rate, DSAR, tons of dry solids/
acre. This value normally ranges from 20 to 40 for typical
forest land sites depending upon tree species, tree maturity,
soil conditions, 'and other factors. Default value = 20 tons/
acre/yr.
A-29.3.5 Annual sludge application period, DRY, days/yr. This value
normally ranges from 130 to 180 days/yr for forest land sites
depending upon climate, soil conditions, and other factors.
Default value = 150 days/yr.
A-29.3.6 Daily sludge application period, HPD, hr/day. This value nor-
mally ranges from 5 to 8 hr/day depending upon equipment used,
site size, and other factors. Default value = 7 hr/day.
A-29.3.7 Frequency of sludge application to forest land at dry solids
application rate (DSAR), i.e., period between application of
sludge to some forest land area, FR, yr. This value varies de-
pending upon tree species, tree maturity, whether trees are
grown for commercial purposes, and other factors. Default
value = 5 yr.
A-29.3.8 Fraction of forest land site area used for purposes other than
sludge application, FWWAB. Varies significantly depending upon
site specific corjditions. Default value = 0.2 for forest land
sites.
A-29.3.9 Fraction of forest land site area requiring clearing of brush
and trees to allow access by application vehicle, FWB. Varies
significantly depending upon site specific conditions. Default
value = 0.05 for forest land sites.
A-29.3.10 Fraction of forest land site requiring extensive grading of
access roads to allow travel by sludge application vehicle,
FR6. Varies significantly depending upon site specific condi-
tions. Default value = 0.05 for forest land sites.
A-29.4 Process Design Calculations
A-29.4.1 Annual dry solids applied to land.
- (SV) (8.34) (SS) (SSG) (365)
" (2,000) (100)
where
TDSS = Annual dry solids applied to land, tons/yr.
A-29.4.2 Sludge disposal area required, not including forest land area
which is used for purposes other than sludge disposal., e.g.,
buffer zone, roads, waste area, etc.
458
-------
SOAR - (T.DSS) (FR)
b : (DSAR)
where
SOAR = Site area required only for sludge disposal, acres.
A-29.4.3 Hourly sludge volume which must be applied.
HSV - (SV) (365)
(DRY) (HPD)
where
HSV = Hourly sludge volume during application period, gal/hr.
A-29.4.4 Capacity of on-site mobile sludge application vehicles. It is
assumed that the; sludge has already been transported to the
forest land sludge application site by a transport process such
as truck hauling. ,The on-site mobile application vehicles
accept the sludge from a large nurse truck, on-site storage
facility, etc., and proceed to the sludge application area to
apply the sludge. Typical on-site mobile sludge application
vehicles at forest land sites are especially modified tank
trucks equipped with a sludge cannon to spray the sludge at
least 100 ft through a 240-degree horizontal arc. The applica-
tion vehicle is modified to handle steep slopes, sharp turn
radius, and doze through small trees and brush. Such vehicles
can negotiate much rougher terrain, e.g., logging roads, than
conventional road tanker trucks. Because of the special condi-
tions encountered in forest land sludge application, it is
assumed that the largest on-site sludge application vehicle
feasible has a capacity of 2,200 gal of sludge. Only two capa-
city increments are included in this program, i.e., 1,000 gal
and 2,200 gal.
A-29.4.4.1 Capacity and number of on-site mobile sludge appli-
cation vehicles. The capacity and number of on-
site mobile sludge application vehicles required is
determined by comparing the hourly sludge volume,
HSV, with the vehicle sludge handling rate, VHRCAP.
See tabl e bel ow.
Vehicle Number of Each
Capacity, NOV Capacity,
CAP. (Gal)
HSV (Gal/Hr) 1,000 2,200
0 - 1,317 1
1,317 - 2,528 - 1
2,528 - 5,056 - 2
5,056 - 7,584 - 3
459
-------
Above 7,584 gal/hr, the number of 2,200-gal capacity vehi
cles is cal cul ated by:
HSV
NOV = $ cy-s (round to next highest integer)
where
NOV = Number of on-site sludge application vehicles.
A-29.4.4.2 Average round trip on-site cycle time for mobile
sludge application vehicles.
CT _ (IT) + (ULT) + (TT)
Ul " 0.75
where
CT = Average round trip on-site cycle time for mobile sludge
application vehicle, min.
LT = Load time, min, varies with vehicle size (see table
below),
ULT = Unload time, min, varies with vehicle size (see table
below).
TT = On-site travel time to and from sludge loading facility
to sludge application area, min. (Assumed values are
shown in table below.)
0.75 = An efficiency factor.
Vehicle
Capacity, CAP
(Sal)
1,000
2,200
LT
(Min)
6
7
ULT
(Min)
8
9
TT
(Min)
10
10
CT
(Min
32
35
A-29. 4. 4. 3 Single vehicle sludge handling rate. The actual
hourly sludge throughput rates for an on-site mobile
sludge application vehicle is dependent upon the
vehicle tank capacity, the cycle time, and an effi-
ciency factor.
VHRCAP -
460
-------
where
VHRCAP = Single vehicle sludge handling rate, gal/hr.
CAP = Vehicle tank capacity, gal.
0.9 = Efficiency factor.
The table below shows VHRCAP values for typical size vehicles.
Vehicle Capacity, VHRCAP
CAP (fial) (Gal/Hr)
1,000 1,317
2,200 2,528
A-29.5 Process Design Output Data
A-29.5.1 Annual sludge quantity, TOSS, tons of dry solids/yr.
A-29.5.2 Sludge disposal area required, SOAR, acres.
A-29.5.3 Capacity of on-site mobile sludge application vehicle, CAP, gal.
A-29.5,4 Number of on-site mobile sludge application vehicles, NOV.
A-29.5.5 Cycle time for on-site mobile sludge application vehicle, CT,
min.
A-29.5.6 Single vehicle sludge handling rate, VHRCAP, gal/hr.
A-29.6 Quantities Calculations
A-29.6.1 Total land area required. For virtually all forest land sites a
larger land area; is required than that needed only for sludge
application/disposal (SOAR). The additional area may be re-
quired for buffer zones, on-site roads, on-site storage, wasted
land due to unsuitable soil or terrain, etc. In any case, the
additional land area required is site specific and varies sig-
nificantly, e.g., from 10 to 50 percent of the SOAR.
TLAR = (1 + FWWAB) (SOAR)
where
TLAR = Total land area required for forest land site, acres.
A-29.6.2 Clearing of brush and trees required. Often a forest land site
will require clearing brush and trees in access road areas to
allow access to the sludge application vehicle.
461
-------
TLAWB = (FWB) (TLAR)
where
TLAWB = Total land area with brush and trees to be cleared, acres.
A -29. 6. 3 Earthwork required. Often a forest land site will require grad-
ing of access roads for the sludge application vehicles, provide
drainage control » etc. The extent of grading required is site-
specific.
TLARG = (FRG) (TLAR)
where
TLARG - Total land area requiring grading, acres.
A -29. 6. 4 Number of monitoring wells required. Virtually all regulatory
agencies require that ground water quality monitoring wells be
installed as a condition of forest land site permitting. The
number and depth .of monitoring wells required varies as a func-
tion of site size, ground water conditions, and regulatory
agency requirements. In this algorithm, it is assumed that even
the smallest forest land site must have one ground water quality
monitoring well, and one additional monitoring well for each 200
acres of total site area (TLAR) above 50 acres.
NQMWR = 1 + " 5° (increase to next highest integer)
where
NOMWR = Number of monitoring wells required.
A-29. 6. 5 Annual operation labor requirement.
i 8 (NOV) (DPY)
L " 0.7
where
L = Annual operation labor requirement, hr/yr.
8 = Hr/day assumed.
0. 7 = Efficiency factor.
A-29.6.6 Annual diesel fuel requirement for on-site mobile sludge appli
cation vehicl es.
462
-------
Fil = (HSV) (HPD) (DPY) (DFRCAP)
ru (VHRCAP)
where
FU = Annual diesel fuel usage, gal/yr.
OFRCAP = Diesel fuel consumption rate for certain capacity vehicle, see
table below, gal/hr.
GALLONS OF FUEL PER HOUR FOR VARIOUS CAPACITY SLUDGE
APPLICATION VEHICLES
l
Vehicle Capacity, OFRCAP
CAP (Gal) (Gal/Hr)
1,000 3
2,200 4
A-29.7 Quantities Calculations Output Data
A-29.7.1 Total land area required, TLAR, acres.
A-29.7.2 Total land area with brush and trees to be cleared, TLAWB,
acres.
A-29.7.3 Total land area requiring grading, TLARS, acres.
A-29.7.4 Number of monitoring wells required, NOMWR.
A-29.7.5 Annual operation 1abor requirement, L, hr/yr.
A-29.7.6 Annual diesel fuel usage, FU, gal/yr.
A-29.8 Unit Price Input Required
A-29.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-29.8.2 Current Marshall and Swift Equipment Cost Index at time analysis
is made, MSEC I.
A-29.8.3 Cost of land, LANDCST, $/acre. Usually the forest land is not
purchased by the municipality. Default value = zero.
A-29.8.4 Cost of clearing brush and trees, BCLRCST, $/acre. Default
value = $l,000/acre (ENRCCI/4,006).
A-29.8.5 Cost of grading earthwork, SEWCST, I/acre. Default value. =
$l,500/acre (ENRCCI/4,006).
463
-------
A-29.8.6 Cost of monitoring well , MWCST, $/well. Default value = $5,000
(ENRCCI/4,006). ;
A-29.8.7 Cost of operational labor, COSTL, $/hr. Default value =
$13.00/hr (ENRCCI/4,006).
A-29.8.8 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-29.9 Cost Calculations
A-29.9.1 Cost of land for forest land application site.
COSTLAND = (TLAR) (LANDCST)
where
COSTLAND = Cost of land for forest land site, $.
A-29.9.2 Cost of clearing brush and trees.
COSTCBT = (TLAWB) (BCLRCST)
where
COSTCBT = Cost of clearing brush and trees, $.
A-29.9.3 Cost of grading earthwork.
COSTEW = (TLARG) (GEWCST)
where
COSTEW = Cost of earthwork grading, $.
A-29.9.4 Cost of monitoring ;wel 1 s.
COSTMW: = (NOMWR) (MWCST)
where
COSTMW = Cost of monitoring wells, $.
A-29.9.5 Cost of on-site mobile sludge application vehicles.
COSTMAV = £(NOV) (COSTPV)] ^1
464
-------
where <
COSTMAV = Cost of on-site mobile sludge application vehicles, $.
COSTPV = Cost/vehicle, obtained from the table below.
COST OF ON-SITE MOBILE SLUDGE APPLICATION VEHICLES (1983)
Vehicle Capacity, COSTPV
CAP (Gal) : (1983 $)
1,000 120,000
2,200 150,000
A-29.9.6 Annual cost of operation labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation labor, $/yr.
A-29.9.7 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-29.9.8 Annual cost of maintenance of on-site mobile sludge application
vehicles.
VMP - r(HSV):(HPD) (PPY) (MCSTCAP)-. MSEC I
L- (VHRCAP)J 751
where
VMC = Annual cost of vehicle maintenance, $/yr.
MCSTCAP = Maintenance cost, $/hr of operation for specific capacity of
vehicle; see table below.
465
-------
HOURLY MAINTENANCE COST FOR VARIOUS CAPACITIES OF FOREST
UNO SLUDGE APPLICATION VEHICLES
Vehicle Capacity, MSCTCAP
CAP (Gal) ($/Hr)
1,000 6.10
2,200 7.30
A -29. 9. 9 Annual cost of maintenance for forest land site (other than
vehicles) including monitoring, recordkeeping, etc.
SMC = t(TLAR) (12)]
where
SMC = Annual cost of forest, land site maintenance (other than vehicles),
$/yr. ;
12 = Annual maintenance cost, $/acre.
A-29.9.10 Total base capital cost.
TBCC = COSTLAND + COSTCBT + COSTEW + COSTMW + GOSTMAV
where
TBCC * Total base capital cost, $.
A-29. 9.11 Total annual operation and maintenance cost.
COSTOM - COS'TLB + COSTDSL + VMC + SMC
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-29. 10 Cost Calculations Output Data
A-29.* 10.1 Cost of land for forest land site, COSTLAND, $.
A-29. 10. 2 Cost of clearing brush and trees, COSTCBT, $.
A-29.10.3 Cost of grading earthwork, COSTEW, $.
A-29. 10. 4 Cost of monitoring wells, COSTMW, $.
466
-------
A-29.10.5 Cost of on-site mobil e sludge application vehicles, COSTMAV, $.
A-29.10.6 Annual cost of operation labor, COSTLB, $/yr.
A-29.10.7 Annual cost of diesel fuel, COSTDSL, $/yr.
A-29.10.8 Annual cost of vehicle maintenance, VMC, $/yr.
A-29.10.9 Annual cost of site maintenance, SMC, $/yr.
A-29.10.10 Total base capital cost of forest land application site using
on-site mobile sludge application vehicles, TBCC, $.
A-29.10.11 Total annual operation and maintenance cost for forest land
application site using on-site mobile sludge application vehi-
cles, COSTOM, $/yr.
467
-------
APPENDIX A-30
LAND APPLICATION TO DEDICATED DISPOSAL SITE
A-30.1 Background
A dedicated land disposal (OLD) site has as its exclusive or primary pur-
pose the land spreading of sludge. Typically, the agency which is implement-
ing the project owns the site(s) or has a long-term lease. This cost algo-
rithm assumes that the land is purchased. It is virtually always the case
that sludge application rates (tons/acre/yr) are much higher for OLD sites
than for the other land application options (cropland, forest land, etc.).
Since the higher sludge application rates may pose a greater potential danger
to surface and ground water quality, the site(s) is more carefully designed,
managed, and monitored than sites where other land application options are
employed. OLD site design and .operation are focused upon containing within
the site any environmentally detrimental sludge constituents.
This cost algorithm estimates only the cost of sludge application at the
OLD site using on-site sludge application vehicles. It is assumed that the
sludge is brought to the OLD site by a transport process, e.g., truck hauling,
pipeline transport, etc. (Algorithms for transport of sludge appear in Appen-
dices A-20 through A-25.) If the same vehicle is used for both the transport
and application of sludge to the site, do not add the cost of the on-site
application trucks to the total base capital cost in this algorithm.
Sludge is often applied to OLD sites throughout the year, operations
halting only during inclement weather. As a result, a layer of sludge may be
applied to the same land as often as 10 to 50 times a year. Sludge applica-
tion rates vary widely, depending on site-specific conditions. Application
rates ranging from 20 to 200 tons of dry sol ids/acre/yr are reported in the
literature, but rates from 30 to 100 tons of dry sol ids/acre/yr are more com-
mon.
A substantial buffer zone is usually required around the sludge applica-
tion area by regulatory agencies. Buffer zone widths are typically 300 to
1,000 ft. ,
Land preparation and improvement costs (e.g., grading, drainage control,
fencing, roads, etc.) are usually capital costs borne by the municipality, and
are included in the cost algorithm. The economic feasibility of a OLD site is
usually determined by the availability of a suitable site within reasonable
distance of the treatment plant, and the cost of the land.
In addition to the purchase of land and site improvements, the total base
capital cost in this algorithm includes installation of monitoring wells and
purchase of on-site mobile sludge application vehicles. Base annual O&M costs
468
-------
include labor, diesel for the operation of vehicles, vehicle maintenance, and
site maintenance. •
A-30.1.1 Al gorithm Development
Design equations in the following algorithm are based on Reference 13,
pages 9-1 through 9-45. Information received from equipment manufacturers was
used to develop capital and O&M costs. Additional cost information was ob-
tained from Reference 14, pages 60 through 61 and pages 86 through 87.
A-30.2 Input Data
A-30.2.1 Daily sludge volume, SV, gpd.
A-30.2.2 Sludge suspended sol ids concentration, SS, percent.
A-30.2.3 Sludge specific gravity, SSG, unit!ess.
A-30.2.4 Average dry solids application rate, DSAR, tons of dry solids/
acre/yr. :
A-30.2.5 Annual sludge application period, DPY, days/yr.
A-30.2.6 Daily sludge application period, HPD, hr/day.
A-30.2.7 Fraction of dedicated disposal site area used for purposes
other than sludge application, e.g., buffer zone, internal
roads, sludge sto'rage, waste land, etc., FWWAB.
A-30.2.8 Fraction of dedicated disposal site area requiring clearing of
brush and trees, FWB.
A-30.2.9 Fraction of land area requiring light grading, FRLG,
A-30.2.10 Fraction of land requiring medium grading, FRMG.
A-30.2.11 Fraction of land requiring extensive grading, FREG.
A-30.3 Design Parameters \
A-30.3.1 Daily sludge volume, SV» gpd. This input value must be pro-
vided by the user. No default value.
A-30.3,2 Sludge suspended solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-30.3.3 Sludge specific gravity, SSG, unit!ess. This value should be
provided by the user. If not available, default value is cal-
culated with the following equation:
SSG =
100 - SS (SS)
100 (1.42) (100)
469
-------
where
SS6 = Sludge specific gravity, unit! ess.
1.42 = Assumed sludge solids specific gravity.
A-30.3.4 Average dry solids application rate, DSAR, tons of dry solids/
acre/yr. This value normally ranges from 30 to 100 for typical
dedicated disposal sites depending upon climate, soil condi-
tions, and other factors. Default value = 60 tons/acre/yr.
A-30.3.5 Annual sludge application period, DRY, days/yr. This value
normally ranges from 150 to 250 days/yr for dedicated disposal
sites depending upon climate, soil conditions, and other fac-
tors. Default value = 200 days/yr.
A-30.3.6 Daily sludge application period, HPD, hr/day. This value nor-
mally ranges from 5 to 8 hr/day depending upon equipment used,
site size, and bther factors. Default value = 7 hr/day.
A-30.3.7 Fraction of dedicated disposal site area used for purposes
other than sludge application, FWWAB. Varies significantly
depending upon site specific conditions. Default value = 0.4
for dedicated disposal sites.
i
A-30.3.8 Fraction of dedicated disposal site area requiring clearing of
brush and trees, FWB. Varies significantly depending upon site
specific conditions. Default value = 0.7 for dedicated dis-
posal sites.
A-30.3.9 Fraction of dedicated disposal site requiring light grading,
FRL6. Varies significantly depending upon site specific condi-
tions. Default value = 0.3.
A-30.3.10 Fraction of dedicated disposal site requiring medium grading,
FRMG. Varies significantly depending upon site specific condi-
tions. Default value = 0.4.
A-30.3.11 Fraction of dedicated disposal site requiring extensive grad-
ing, FRE6. Varies significantly depending upon site specific
conditions. Default value = 0.3.
A-30.4 Process Design Calculations
A-30.4.1 Annual dry solids applied to land.
TDSc = (SV) (8.34) (SS) (SSG) (365)
(2,000) (100)
where
TOSS = Annual dry solids applied, tons/yr.
470
-------
A-30.4.2 Sludge disposal; area required, not including dedicated site
disposal area which is used for purposes other than sludge dis-
posal , e.g., buffer zone, roads, waste area, etc.
SDAR . Eg?*?
* * (DSAR)
where
SDAR = Site area required only for sludge disposal, acres.
A-30.4.3 Hourly sludge application rate.
(SV) (365)
" (DPY) (HPD)
where
HSV = Hourly sludge application rate, gal/hr.
A-30.4.4 Capacity of on-site mobile sludge application vehicles. It is
assumed that the sludge has been transported to the dedicated
sludge disposal site by a process such as large haul vehicle,
pipeline, etc. The on-site mobile application vehicles accept
the sludge from the large nurse truck, on-site storage facil-
ity, etc., and proceed to the sludge application area to apply
the sludge. Typical on-site mobile sludge application vehicles
at dedicated disposal sites have capacities ranging from 1,600
to 4,000 gal, in the following increments: 1,600, 2,200,
3,200, and 4,000 gal.
A-30.4.4.1 Capacity and number of on-site mobile sludge appli-
cation vehicles. The capacity and number of on-
site mobile sludge application vehicles required is
determined by comparing the hourly sludge volume,
HSV, with the vehicle sludge handling rate, VHRCAP.
See tab! e be! ow.
Vehicle Number of Each Capacity, NOV
Capacity. CAP (Gal)
0
3,456
4,243
5,574
6,545
8,500
11,200
13,100
19,600
- 3,456
- 4,243
- 5,574
- 6,545
- 8,500
- 11,200
- 13,100
- 19,600
- 26,000
HSV (Gal/Hr) ; 1,600 2,200 3,200 4,000
1
— 1 — —
- - 1 -
1
- 2 -• -
', 2
2
3
4
471
-------
Above 26,000 gal/hr, the number of 4,000-gal capacity vehicles
required is calculated by:
LJCU
NQV = f clc (round to the next highest integer)
where
NOV = Number of on-site sludge application vehicles.
A-30.4.4.2 Average round trip on-site cycle time for mobile
sludge application vehicles.
rr - (IT) + (ULT) + (TT)
tr _^__.i_
where
CT = Average round trip on-site cycle time for mobile sludge
application vehicle, min.
LT = Load time, min, varies with vehicle size (see table
bel ow).
ULT = Unload time, min, varies with vehicle size (see table
below).
TT = On-site travel time to and from sludge loading facility
to sludge application area, min. (assumed values are
shown in:table below).
0.75 = An efficiency factor.
Vehicle
Capacity, CAP
(Gal)
1,600
2,200
3,200
4,000
LT
(Min)
6
7
8
9
ULT
(Min)
8
9
10
11
TT
(Min)
5
5
5
5
CT
(Min
25
28
31
33
A-30. 4. 4. 3 Single vehicle sludge handling rate. The actual
hourly sludge throughput rates for an on-site
mobile sludge application vehicle is dependent upon
the vehicle tank capacity, the cycle time, and an
efficiency factor.
\\f l ;
472
-------
where .
VHRCAP = Single vehicle sludge handling rate, gal/hr.
CAP - Vehicle tank capacity, gal,
CT = Cycle time, min.
0.9 = Efficiency factor.
The table below shows VHRCAP values for typical size vehicles.
Vehicle'Capacity, VHRCAP
CAP (6al) (Gal/Hr)
1,600 3,456
2,200 4,243
3,200 5,574
4,000 6,545
A-30.5 Process Design Output Data
A-30.5.1 Annual dry solids applied to land, TDSS, tons/yr.
A-30.5.2 Sludge disposal area required, SOAR, acres.
A-30.5.3 Hourly sludge application rate, HSV, gal/hr.
A-30.5.4 Capacity of on-site mobile sludge application vehicle, CAP,
gal« '
A-30.5.5 Number of on-site; mobil e sludge application vehicles, NOV.
A-30.5.6 Cycle time for oh-site mobile sludge application vehicle, CT,
min.
A-30.5.7 Single vehicle sludge handling rate, VHRCAP, gal/hr,
A-30.6 Quantities Calculations
A-30.6.1 Total land area required. For virtually all dedicated disposal
sites a larger land area is required than that needed only for
sludge application/disposal (SOAR). The additional area may be
required for buffer zones, on-site roads, on-site storage, and
wasted land due to unsuitable soil or terrain. In addition,
the owner may have to purchase more land than actually needed
due to the size of land parcels available. In any case, the
additional land area required is site specific and varies sig-
nificantly, e.g., from 10 to 100 percent of the SOAR.
I
TLAR = (1 + FWWAB) (SOAR)
473
-------
where
TLAR = Total land area required for dedicated disposal site, acres.
A-30.6.2 Clearing of brush and trees required. Often a potential dedi-
cated disposal site will contain brush and trees which must be
cleared prior to site grading.
TLAWB = (FWB) (TLAR)
where
TLAWB = Total land area with brush and trees to be cleared, acres
A-30.6.3 Earthwork required. Usually a potential dedicated disposal
site will require grading to smooth out contours, provide
drainage control, etc. The extent of grading required is very
site specific, and can represent a significant portion of the
total land cost :when the terrain is rough.
TLARLG = (FRLG) (TLAR)
TLARMG = (FRMG) (TLAR)
TLAREG = (FREG) (TLAR)
where
TLARLG = Total land
TLARMG = Total land
TLAREG = Total land
area requiring light grading, acres.
area Requiring medium grading, acres.
area requiring extensive grading, acres.
A-30.6.4 Number of monitoring wells required. Virtually all regulatory
agencies require that ground water quality monitoring wells be
installed as a condition of dedicated disposal site permitting.
The number and depth of monitoring wells required varies as a
function of site size, ground water conditions, and regulatory
agency requirements. In this algorithm, it is assumed that
even the smallest dedicated disposal site must have two ground
water quality monitoring wells, and one additional monitoring
well for each 40 acres of total site area (TLAR) above 40
acres.
NOMWR = 2 +
(TLAR) - 40
(increase to next highest integer)
where
NOMWR = Number of monitoring wells required.
474
-------
A-30.6,5 Annual operation labor requirement.
i 8(NOV) (DPY)
L ~ 0.7
where ;
L = Annual operation labor requirement, hr/yr.
8 - Hr/day assumed.
0.7 = Efficiency factor. '
A-30.6.6 Annual diesel fuel requirements for on-site mobile sludge
application vehicles.
PII _ (HPD) (DPY) (DFRCAP)
ru (VHRCAP)
where
FU = Annual diesel fuel;usage, gal/yr.
DFRCAP = Diesel fuel consumption rate for certain capacity city vehicle,
see table below, gal/hr.
GALLONS OF FUEL PERiHOUR FOR VARIOUS CAPACITY SLUDGE
APPLICATION VEHICLES
Vehicle Capacity. CAP (Gal) DFRCAP (Gal/Hr)
1,600 3.5
2,200 4
3,200 5
4,000 6
A-30.7 Quantities Calculations Output Data
A-30.7.1 Total land area required, TLAR, acres.
A-30.7.2 Total land area With brush and trees to be cleared, TLAWB,
acres.
A-30.7.3 Total land area requiring light grading, TLARLG, acres.
A-30.7.4 Total land area requiring medium grading, TLARMG, acres.
A-30.7.5 Total land area requiring extensive grading, TLAREG, acres.
A-30.7.6 Number of monitoring wells required, NOMWR.
475
-------
A-30.7.7 Annual operation labor requirement, L, hr/yr.
A-30.7.8 Annual diesel fuel usage, FU, gal/yr.
A-30.8 Unit Price Input Required
A-30.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-30,8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-30.8.3 Cost of land, LANDCST, $/acre. Default value = $3,000/acre.
A-30.8.4 Cost of clearing brush and trees, BCLRCST, $/acre.
Default value = $l,000/acre (ENRCCI/4,006).
A-30.8.5 Cost of light grading earthwork, LGEWCST, $/acre. Default
value = $l,QOQ/acre (ENRCCI/4,006).
A-30.8.6 Cost of medium grading earthwork, MGEWCST, $/acre. Default
value = $2,000/acre (ENRCCI/4,006).
A-30.8.7 Cost of extensive grading earthwork, EGEWCST, $/acre. Default
value = $5,000/acre (ENRCCI/4,006).
A-30,8.8 Cost of monitoring well(s), MWCST, $/well. Default value =
$5,000 (ENRCCI/4,006).
A-30.8.9 Cost of operational labor, COSTL, $/hr. Default value =
$13,OQ/hr (ENRCCI/4,006).
A-30.8.10 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006). '
A-30.9 Cost Cal cul ations
A-30.9.1 Cost of land for dedicated disposal site.
COSTLAND = (TLAR) (LANDCST)
where
COSTLAND = Cost of land for dedicated disposal site, $.
A-30.9.2 Cost of clearing brush and trees.
COSTCBT = (TLAWB) (BCLRST)
476
-------
where
COSTCBT = Cost of clearing brush and trees, $.
A-30.9.3 Cost of grading earthwork.
COSTEW = (TLARLG) (LGEWCST) + (TLARMG) (MGEWCST) + (TLAREG) (ESEWCST)
where
COSTEW = Cost of grading earthwork, $.
A-30.9.4 Cost of monitoring wells.
COSTMW = (NOMWR) (MWCST)
where
COSTMW = Cost of monitoring wells, $.
A-30.9.5 Cost of on-site mobile sludge application vehicles.
MS EC I
COSTMAV = [(NOV) (COSTPV)]
where
COSTMAV = Cost of on-site mobile sludge application vehicles, $.
COSTPV = Cost of vehicle, obtained from the table below.
COST OF ON-SITE MOBILE SLUDGE APPLICATION VEHICLES (1983)
Vehicle Capacity, CAP (Gal) COSTPV, 1983 $
1,600 85,000
2,200 95,000
3,200 ; 120,000
4,000 140,000
A-30.9.6 Cost of miscellaneous site improvements, including fencing,
drainage structures, lighting, buildings, etc. Obviously, this
cost is highly variable depending upon site conditions. For
the purpose of this program, the cost of these miscellaneous
improvements have been made a function of total dedicated land
disposal site size (TLAR).
477
-------
MISCST = [(TLAR) (2,500)]
where
MISCST = Cost of miscellaneous site improvements, $.
2,500 = Cost of miscellaneous site improvements, $/acre.
A-30.9.7 Annual cost of operation labor.
COSTLB = (L) (COSTL)
where
COSTLB = Annual cost of operation labor, $/yr.
A-30.9.8 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel , $/yr.
A-30.9.9 Annual cost of maintenance for on-site mobile sludge applica-
tion vehicles.
VMr _ r(H$V) (HPD) (DPY) (MCSTCAP)-, MSEC I
VMO " L(VHRCAP)J ~75T~
where
VMC = Annual cost of vehicle maintenance, $/yr.
MCSTCAP = Maintenance cost, $/hr of operation, for specific capacity of
vehicle; see table below.
HOURLY MAINTENANCE COST FOR VARIOUS CAPACITIES OF SLUDGE
APPLICATION VEHICLES
Vehicle Capacity, CAP (Gal) MCSTCAP, $/hr
1,600-' 4.85
2,200 5.31
3,200 5.96
4,000 7.16
478
-------
A-30. 9.10 Annual cost of maintenance for dedicated disposal site (other
than vehicles) including monitoring, recordkeeping, etc.
SMC = [(TLAR) (100)3
where
SMC = Annual cost of site maintenance (other than vehicles) for dedicated
disposal , $/yr.
100 = Annual maintenance cost, $/acre.
A-30. 9. 11 Total base capital cost.
TBCC = COSTLAND + COSTCBT + COSTEW + COSTMW +-COSTMAV + MISCST
where
TBCC = Total base capital cost, $.
A-30. 9. 12 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTDSL + VMC + SMC
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-30.10 Cost Calculations Output Data
A-30. 10. 1 Cost of land for dedicated disposal site, COSTLAND, $.
A-30.1Q.2 Cost of clearing brush and trees, COSTCBT, $.
A-30. 10. 3 Cost of grading earthwork, COSTEW, $.
A-30. 10. 4 Cost of monitoring wells, COSTMW, $.
A-30.10.5 Cost of on-site mobile sludge application vehicles, COSTMAV, $.
A-30. 10.6 Cost of miscellaneous site improvements, MISCST, $.
A-30. 10.7 Annual cost of operation labor, COSTLB, $/yr.
A-30.10.8 Annual cost of diesel fuel, COSTDSL, $/yr.
A-30. 10. 9 Annual cost of vehicle maintenance, VMC, $/yr.
479
-------
A-30.10.10 Annual cost of site maintenance, SMC, $/yr.
A-30.1Q.11 Total base capital cost of dedicated land disposal site using
on-site mobile sludge application vehicles, TBCC, $.
A-30.10.12 Annual operation and maintenance cost for dedicated land dis-
posal site using on-site mobile sludge application vehicles,
COSTOM, $/yr.
480
-------
APPENDIX A-31
LAND DISPOSAL TO SLUDGE LANDFILL
A-31.1 Background
This process algorithm covers sludge landfills owned and operated by the
sludge generating agency for the exclusive purpose of disposing of dewatered
sewage sludge. Many municipalities dispose of their sewage sludge to land-
fills operated by other private or public entities. In these cases the muni-
cipality usually pays a disposal (tipping) fee to the landfill owner based
upon cost per unit weight or volume of sludge. This process algorithm does
not cover landfill disposal to'another entity.
Sludge landfill ing is defined as a disposal method involving the burial
of sludge, i.e., the application of sludge on the land and subsequent burial
by applying a layer of cover soil over the sludge. Cover is usually applied
daily. Not included in this process are sludge to land applications by
spreading where the sludge is spread on the soil surface or injected in the
top soil layer, e.g., dedicated land disposal site, application to food chain
crops, etc. These land application processes are covered in Appendices A-26
through A-30.
Sludge landfill methods in use are:
* Narrow trenching, which is defined as sludge disposal to trenches less
than 10 ft wide.
• Wide trenching, which is defined as sludge disposal to trenches more
than 10 ft wide.
* Codisposal with municipal refuse in a conventional municipal refuse
landfill. As previously noted, this disposal method is not included
in this process.
For the purpose of this algorithm, it is assumed that the sludge landfill
methods involving trenching are conducted on a site owned by the agency which
generates the sludge. In addition to the purchase of land, the base capital
cost obtained using this algorithm includes site improvements (brush clearing,
grading, etc.), installation of monitoring wells, purchase of excavation vehi-
cles, and purchase of earth-moving vehicles. Total base annual cost includes
operation labor, diesel fuel for machinery, machinery maintenance, and site
maintenance.
Note that this process cost algorithm does not include any costs for
transporting sludge from the treatment plant(s) to the landfill site, nor any
' 481
-------
costs involved in the treatment of sludge, e.g., stabilization, dewatering,
etc. Costs for these processes may be obtained using the algorithms in other
appendices.
From a regulatory viewpoint, a sludge landfill may be considered similar
to a hazardous waste disposal site. In many instances there will be required
ground water quality protection improvements, such as liners, 1 eachate collec-
tion systems, etc., as well as surface water quality protection improvements,
such as surface drainage control/col lection structures. In a general cost
program such as this one, it is ^impossible to take into account all of these
types of site-specific variables. The user is particularly cautioned that
this algorithm does not incl ude the cost of liners or leachate collection sys-
tems.
A-31.1.1 Al gorithm Development
Capital costs of equipment in this algorithm were obtained from manufac-
turers. 0AM requirements were provided by Caterpillar Performance Handbook,
Reference 16, pages 28-1 through 28-40. Additional information was obtained
from Reference 4, pages 19-3 through 19-25, and Reference 17, pages 5-1
through 10-32.
A-31.2 Input Data
A-31.2.1 Daily sludge volume, SV, gpd.
A-31.2.2 Site life, SL, yr.
A-31.2.3 Trench width, TW, ft. Assume vertical side-walls for trenches.
A-31.2.4 Trench depth, TD, ft. Assume 2 ft of soil cover for top 2 ft
of each trench.
A-31.2.5 Trench spacing, TS, ft. This is the horizontal distance be-
tween the edges of trenches.
A-31.2.6 Annual sludge application period, DRY, days/yr.
A-31.2.7 Daily sludge application period, HPD, hr/day.
A-31.2.8 Fraction of landfill site used for purposes other than sludge
trenching, e.g., buffer zones, internal roads, cover soil stor-
age, etc., FWWAB.
A-31.2.9 Fraction of raw landfill disposal site requiring clearing of
brush and trees, FWB.
A-31.2.10 Fraction of raw landfill disposal site requiring grading, FRG.
A-31.3 Design Parameters
A-31.3.1 Daily sludge volume to be landfilled, SV, gpd. This input
value must be provided by the user. No default value.
482
-------
A-31.3.2 Landfill site life, SL, yr. Default value = 20 yr.
A-31.3.3 Trench width, TW, ft. Default value = 10 ft (assume vertical
sidewalls for trenches).
A-31.3.4 Trench depth, TO, ft. Default value = 10 ft.
A-31.3.5 Trench spacing, i.e., distance between edges of trenches, TS,
ft. Default value = 15 ft.
A-31.3.6 Annual sludge application period, DRY, days/yr. Default value
« 240 days.
A-31.3,7 Daily sludge application period, HPD, hr/day. Default value =
7 hr/day.
A-31.3.8 Fraction of raw landfill site used for purposes other than
sludge trenching, FWWAB. Default value = 0.3.
A-31.3.9 Fraction of raw; landfill disposal site requiring clearing of
brush and trees, FWB. Default value = 0.7.
A-31.3.10 Fraction of raw landfill disposal site requiring initial grad-
ing, FRG. Default value = 0.7.
A-31.4 Process Design Calculations
A-31.4.1 Calculate total volume of sludge to be landfilled during site
1 i f e. :
- (SV) (SL) (365)
(202)
where
o
TSV = Total sludge volume to be^landfilled over site life, yd .
202 = Conversion factor, gal/yd .
A-31.4.2 Calculate total trench volume required during site life.
TV - (TSV) (TD)
IV - "
where
TV = Total trench volume required during site life, yd-*.
2 = Assumed depth of cover soil in trench, ft.
A-31.4.3 Calculate area of landfill site required only for sludge dis-
posal, i.e., not including additional area required for buffer
zone, on-site roads, etc.
483
-------
SOAR
= 3)(
.
(TD) (TW) (4,840)
where
SOAR = Area of landfill required only for sludge disposal, acres.
3 = Conversion factor^ ft/yd.
4,840 = Conversion factor, yd^/acre.
A-31.4.4 Calculate required hourly capacity of earth excavation digging
machine(s).
EVR =
(TV)
(SI) (DRY) (HPD) (0.70)
where
EVR = Average earth excavation rate requirement for digging machine(s),
yd^/hr.
0.70 = Efficiency factor.
A-31.4. 5 Calculate required hourly capacity of earth-moving and cover
material application machine(s).
(TV) (2)
(SL) (DPY) (HPD) (TD) (0.5)
where
EMR » Average earth-moving and cover material application rate
requirement for earth-moving machine(s), yd /hr.
2 = Assumed depth of cover material » ft.
0.5 = An efficiency factor.
A-31.4. 6 Size and number of earth excavation machines. It is assumed
that this machine is a backhoe for smaller landfill sites and
an excavator for larger landfill sites. The size and number of
earth excavation machines is determined by comparing the re-
quired hourly capacity of the earth excavation machine, EVR,
with standard excavation rates for various size earth excava-
tion machines. See table below.
484
-------
NUMBER OF EARTH-EXCAVATING MACHINES OF EACH CAPACITY, NOVEX
Required Capacity of Excavating Machines, CAPEX
Excavation (Yd3/Hr)
Rate, EVR,
Yd3/Hr 2Q_ 5Q_ 100 150 200 250 300
0-20 i - - - - -
20-50 _ i -
50-100 - 1
100-150 - 1
150 -200 ___ _ i
200-250 - - - 1
250-300 - ' - - - - 1
300-400 - • - - 2
400-500 - ' - - - 2
-------
Required Capacity of Earth-Moving Machines, CAPMV
Earth-Moving (Yd3/Hr)
Rate.. EMR,
Yd3/Hr
25 - 50
50 - 75
75 - 100
100 - 200
200 - 300
300 - 400
400 - 600
i
10 25 50 75 100 200
— _ i - - —
: _ _ i
1
_ i
X
_ _
2
_____ -
300
_
-
-
1
-
2
Above 600 yd3/hr, the number of 300 yd3/hr earth-moving machines
needed is calculated by:
NOVMV = |||y (round to the next highest integer)
where
NOVMV = Number of earth-moving machines required.
CAPMV = Capacity of earth-moving machine(s), yd3/hr.
A-31.5 Process Design Output Data
A-31,5.1 Total volume of sludge to be landfilled over site life, TSV,
yd3.
A-31.5.2 Total trench volume required during site life, TV, yd3.
A-31.5.3 Sludge disposal area required, SOAR, acres.
A-31.5.4 Average earth "excavation rate requirement for digging ma-
chine(s), EVR, ydj/hr.
A-31.5.5 Average earth-moving and cover application rate requirement for
earth-moving and cover application machine(s), EMR, yd^/hr.
A-31,5.6 Number of earth excavation machines required, NOVEX.
A-31.5.7 Capacity of earth excavation machine(s) required, CAPEX,
yd3/hr.
A-31.5.8 Number of earth-moving and cover application machines required,
NOVMV.
A-31.5.9 Capacity of earth-moving machine(s) required, CAPMV, yd3/hr.
486
-------
A-31.6 Quantities Calculations
A-31.6.1 Total land area required. For virtually all sludge landfill
sites a larger land area is required than that needed only for
sludge application/disposal (SOAR). The additional area may be
required for buffer zones, on-site roads, on-site storage,
wasted land due to unsuitable soil or terrain. In addition,
the agency may have to purchase more land than actually needed
due to the size of land parcels available. In any case, the
additional land area required is site-specific and varies sig-
nificantly, e.g., from 10 to 100 percent of the SOAR.
TLAR =? (1 + FWWAB) (SOAR)
where
TLAR = Total land area required for landfill site, acres.
A-31,6.2 Clearing of brush and trees required. Often a potential land-
fill site will contain brush and trees which must be cleared
prior to site grading.
TLAWB = (FWB) (TLAR)
where
TLAWB = Total land area with brush and trees to be cleared, acres.
A-31.6.3 Earthwork required. Usually a potential landfill site will re-
quire grading to smooth out contours, provide drainage control,
etc. The extent of grading required is very site-specific, and
can represent a significant portion of the total site develop-
ment cost when the terrain is rough.
TLARG = (FRG) (TLAR)
where
TLARG = Total land area requiring grading, acres.
A-31.6.4 Number of monitoring wells required. Virtually all regulatory
agencies require that ground water quality monitoring wells be
installed as a condition of landfill site permitting. The num-
ber and depth of monitoring wells required varies as a function
of site size, ground water conditions, and regulatory agency
requirements. In this algorithm, it is assumed that even the
smallest landfill site must have two ground water quality moni-
toring wells, with one additional monitoring well for each 50
acres of total site area (TLAR) over 20 acres.
487
-------
NOMWR = 2 + ^TLA5Q " 2° (increase to next highest integer)
where
NOMWR = Number of monitoring wells required.
A-31.6.5 Annual operation labor requirement.
L = 8 (NOVEX + NOVMV) (DPY)
where
L = Annual operation labor requirement, hr/yr.
8 = Hr/day assumed.
0.7 = Efficiency factor.
A-31.6.6 Annual diesel fuel requirement for on-site earth excavation and
earth-moving machines.
Fll . C(EVR) + (EMR)] (HPD) (DPY) [(NOVEX) (DFREX)-•+ (NOVMV) (DFRMV)]
L(NOVEX) (CAPEX) + (NOVMV) (CAPMV)J
where
FU = Annual diesel fuel usage, gal/yr.
DFREX = Diesel fuel consumption rate for specific capacity (CAPEX) exca-
vating machine(s) to be used., gal/hr; use table below.
DFRMV = Diesel fuel consumption rate for specific capacity (CAPMV) earth-
moving machine(s) to be used, gal/hr; use table below.
GALLONS OF FUEL/HOUR FOR VARIOUS CAPACITY
EARTH-HANDLING MACHINES
Machine Capacity,
CAPEX or CAPMV, DFREX or DFRMV,
As Appropriate, As Appropriate,
Yd3/Hr Gal/Hr
10 2
25 3
50 4
75 5
100 6
150 8
200 10
250 12
300 14
488
-------
A-31.7 Quantities Calculations Output Data
A-31.7.1 Total land area required, TLAR, acres.
A-31.7.2 Total land area with brush and trees to be cleared, TLAWB,
acres.
A-31.7.3 Total land area requiring grading, TLARG, acres.
A-31.7.4 Number of monitoring wells required, NOMWR.
A-31.7.5 Annual operation labor requirement, L, hr/yr.
A-31.7.6 Annual diesel fuel usage, FU, gal/yr.
A-31.8 Unit Price Input Required
A-31.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-31.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSECI.
A-31.8.3 Cost of land, LANDCST, $/acre. Default value = $3,000/acre.
A-31.8.4 Cost of clearing brush and trees, BCLRCST, $/acre. Default
value = $l,000/acre (ENRCCI/4,006).
A-31.8.5 Cost of initial site grading earthwork, GEWCST, $/acre.
Default value = $l,500/acre (ENRCCI/4,006).
A-31.8.6 Cost of monitoring well(s), MWCST, $/well. Default value =
$5,000/well (ENRCCI/4,006).
A-31.8.7 Cost of operation labor, COSTL, $/hr. Default value = $13.00/
hr (ENRCCI/4,006).
A-31.8.8 Cost of diesel fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-r31.9 Cost Calculations
A-31.9.1 Cost of land.
COSTLAN'D = (TLAR) (LANDCST)
where
COSTLAND = Cost of land for landfill site, $.
489
-------
A-31.9.2 Cost of clearing brush and trees.
COSTCBT = (TLAWB) (BCLRCST)
where
COSTCBT = Cost of clearing brush and trees, $.
i
A-31.9.3 Cost of grading earthwork.
COSTEW = (TLARG) (GEWCST)
where
COSTEW = Cost of grading earthwork, $.
A-31.9.4 Cost of monitoring wells.
COSTMW » (NOMWR) (MWCST)
where
COSTMW = Cost of monitoring wells, $.
A-31.9.5 Cost of on-site earth excavation equipment.
TOTCOSTEV = [(NOVEX) (COSTEV)]
where
TOTCOSTEV = Cost of earth excavation equipment, $.
COSTEV = Cost per earth excavation machine, $, obtained from table
be! ow.
Capacity of Earth-
Excavating Machine(s),
CAPEX, Yd^/Hr COSTEV, 1983 $
20 80,000
50 120,000
100 175,000
150 255,000
200 320,000
250 410,000
300 480,000
490
-------
A-31.9.6 Cost of on-site earth-moving and cover soil application equip-
ment.
TOTCOSTMV = [(NOVMV) (COSTMV)]
where
TOTCOSTMV = Total cost of earth-moving and cover soil application equip-
ment, $.
COSTMV = Cost per earth-moving machine, $, obtained from table below.
Capacity of Earth-
Moving Machine(s),
CAPMV. Ydd/Hr CO.STMV. 1983 $
10 75,000
25 90,000
50 115,000
75 150,000
100 170,000
200 : 320,000
300 450,000
A-31.9.7 Cost of miscellaneous site improvements, including fencing,
drainage structures, lighting, buildings, etc. Obviously, this
cost is highly variable depending upon site conditions. For
the purpose of this program, the cost of these miscellaneous
improvements have been made a function of total landfill site
size (TIAR).
MISCST = C(TIAR) (1,000)] ENRCCI
4,OTJb
where
MISCST = Cost of miscellaneous site improvements, $.
1,000 = Cost of miscellaneous site improvements, $/acre.
A-31.9.8 Annual cost of operation labor.
COSTLB = (L) (COSTL)
where
COSTLB - Annual cost of operation labor, $/yr.
491
-------
A-31.9.9 Annual cost of diesel fuel.
COSTDSL = (FU) (COSTDF)
where
COSTDSL = Annual cost of diesel fuel, $/yr.
A-31.9.10 Annual cost of maintenance of on-site earth excavation and
earth-moving machines.
VMP = r(EVR + EMR) (HPD) (DPY) [(NOVEX) (MCSTEX) + (NOVMV) (MCSTMV)]-, MSEC I
vm, ,_-,[(NOVEX) (CAPEX) 4- (NQVMV) (CAPMV)J* 751
where
VMC = Total annual machine maintenance cost, $/yr.
MCSTEX = Maintenance cost, $/hr of operation, for the specific-capacity
(CAPEX) excavating'machine(s) to be used; see table below.
MCSTMV = Maintenance cost, $/hr of operation, for specific-capacity earth-
moving machine(s) to be used, see table below.
HOURLY MAINTENANCE COSTS FOR VARIOUS CAPACITIES OF EARTH-
EXCAVATING AND MOVING MACHINES
Machine Capacity,
CAPEX or CAPMV,
As Appropriate, MCSTEX or MCSTMV, As Appropriate,
-^ _ (1983 $/Hr) _
10 4
25 5
50 7
75 9
100 11
150 13
200 16
250 18
300 20
A-31.9.11 Annual cost for maintenance of landfill site (other than
machines), e.g., monitoring, recordkeeping, etc.
SMC - I(TLAR) (100)] ENRCCI
4,006
492
-------
where
SMC = Annual cost of landfill site maintenance (other than vehicles),
$/yr.
100 = Annual maintenance cost, $/acre.
A-31.9.12 Total base capital cost.
TBCC = COSTLAND -t- COSTCBT + COSTEW + COSTMW + TOTCOSTEV + TOTCQSTMV + MISCST
where
TBCC = Total base capital cost, $.
A-31.9.13 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTDSL + VMC + SMC
where
COSTOM = Annual operation and maintenance cost, $/yr.
\-31.10 Cost Calculations Output Data
A-31.10.1 Cost of land for landfill site, COSTLAND, $.
A-31.10.2 Cost of clearing brush and trees, COSTCBT, $.
A-31.10.3 Cost of grading earthwork, COSTEW, $.
A-31,10,4 Cost of monitoring wells, COSTMW, $.
A-31,10.5 Cost of on-site earth excavation equipment, TOTCOSTEV, $.
A-31.10.6 Cost of on-site earth-moving and cover soil application equip-
ment, TOTCOSTMV, $.
A-31.10.7 Cost of miscellaneous site improvements, MISCST, $.
A-31.10.8 Annual cost of operation labor, COSTLB, $/yr.
A-31.10.9 Annual cost of diesel fuel, COSTDSL, $/yr.
A-31.10.10 Annual cost of machinery maintenance, VMC, $/yr.
A-31.10.11 Annual cost of site maintenance, SMC, $/yr.
493
-------
A-31,10.12 Total base capital cost of sludge landfill site using on-site
earth-excavating and moving equipment, TBCC, $.
A-31.10.13 Annual operation and maintenance cost for sludge landfill site
using on-site earth-excavating and moving equipment, COSTOM,
$/yr.
494
-------
APPENDIX A-32
SLUDGE STORAGE - FACULTATIVE LAGOONS
A-32.1 Background
Facultative sludge lagoons have been used extensively in sludge manage-
ment systems. In order to minimize severe odor problems often encountered in
facultative lagoons, it is generally advisable to store only stabilized
sludges (e.g., anaerobically digested sludges) in facultative lagoons.
Facultative sludge lagoons consist of an aerobic surface layer, usually
from 1 to 3 ft deep, a deeper anaerobic zone below, and a sludge storage zone
on the bottom. Both the aerobic and anaerobic zones are biologically active
with anaerobic stabilization providing substantial reduction of organic mate-
rial. Dissolved oxygen is supplied to the aerobic zone by (1) surface aera-
tors, (2) algae photosynthesis, and (3) surface transfer from the atmosphere.
Sludge accumulates in the lagoons and must be periodically removed.
The key to successful operation of a facultative sludge lagoon is to
maintain proper organic loading. Lagoons have operated successfully at maxi-
mum annual organic loadings of 20 Ib volatile solids/1,000 ffvday. Loadings
as high as 40 Ib volatile solids/1,000 ft^/day have been used successfully for
several months during warm weather.
Typically, surface aerators in facultative lagoons assist in providing
oxygen to the aerobic zone. In addition, surface aerators prevent the buildup
of scum on the surface, and provide distribution of solids in the anaerobic
zone. In this design, two floating brush type aerator-mixers are used in each
lagoon, and at least two lagoons are specified for each plant. The lagoons
are unlined, constructed of compacted soil with a crest width of 15 ft and 3:1
side slopes. The recommended maximum lagoon surface area is 4 acres or about
175,000 ftf. Typical liquid depth is 12 ft, which gives a volume of about
523,000 ft3/acre of surface area.
The following algorithm is based on the construction and operation of a
facultative lagoon with design conditions as mentioned above. Base capital
costs include purchase of land, excavation and construction of the lagoon, and
purchase and installation of aerators. Base annual O&M costs include labor,
electrical energy, and replacement parts and materials. Costs do not include
provisions for the removal of sludge from the lagoons.
A-32.1.1 Al gori thm Devel opment
Typical design parameters used in this process algorithm were discussed
above. Base capital costs and annual O&M requirements were obtained from in-
house documents provided by Cul p/Wesner/Cul p Consulting Engineers.
495
-------
A-32.2 Input Data
A-32.2.1 Daily sludge volume input to lagoon, SV, gal/day.
A-32.2.2 Sludge solids concentration, SS, percent.
A-32.2.3 Sludge specific gravity, SS6, unitless.
A-32.2.4 Percent volatile solids in sludge, VSP, percent of dry solids.
A-32.2.5 Volatile solids destroyed during storage, VSDP, percent of
volatile sol ids.
A-32.2.6 Lagoon loading rate, LL, Ib VSS/1,000 ft2/day.
A-32.2.7 Thickened sludge solids content in lagoon, TSC, percent.
A-32.2.8 Lagoon liquid depth, LD, ft.
A-32.3 Design Parameters
A-32.3.1 Daily sludge volume input to lagoon, SV, gal/day. This input
value must be provided by the user. No default value.
A-32.3.2 Sludge solids concentration, SS, percent. This input value
must be provided by the user. No default value.
A-32.3.3 Sludge specific gravity, SS6, unitless. This value should be
provided by the user. If not available, default value is cal-
culated with the following equation:
SSG = 100 - SS , (SS)
100 (1.42) (100)
where
SSG = Sludge specific gravity, unitless.
1.42 = Assumed specific gravity of sludge solids.
A-32.3.4 Volatile solids concentration, VSP, expressed as a percent of
the dry solids weight. Default value = 35 percent.
A-32.3.5 Volatile solids destroyed during storage, VSDP, expressed as a
percent of the volatile solids. Default value = 40 percent.
A-32.3.6 Lagoon leading, LL. Default value = 20 1 b volatile solids/
1,000 ftVday.
A-32.3.7 Thickened sludge solids content in lagoon, TSC. Default value
= 6 percent.
A-32.3.8 Lagoon liquid depth, LD. Default value = 12 ft.
496
-------
A-32.4 Process Design Calculations
A-32.4.1 Calculate dry solids input to lagoon per day.
DSS = (SV) (8.34) (SSG) (SS)
U55 (100)
where
DSS = Sludge dry solids input to lagoon, Ib/day.
8.34 = Density of water, lb/gal.
A-32.4. 2 Calculate volatile solids input to lagoon per day.
VSS - U x DSS
where
VSS = Volatile solids input to lagoon, 1 b/day.
A-32.4. 3 Calculate the volatile solids destroyed.
- (VSS) (VSDP)
_
where
VSD = Volatile solids destroyed, 1 b/day.
A-32.4. 4 Calculate lagoon surface area required,
TLSA = (1,000)
where
TLSA = Total lagoon surface area, ft^.
1,000 = Conversiort factor for lagoon loading rate.
A-32.4. 5 Calculate number of lagoons. Maximum surface area of each
lagoons is 4 acres and a minimum of two lagoons are required.
NOL - TLSA
(43,560) (4)
497
-------
where
NOL = Number of lagoons; ,1f NOL less than 2, use 2.
43,560 = Conversion factor, ft^/acre.
4 - Maximum surface area of each lagoon, acres.
A-32.4.6 Calculate area of each lagoon.
LSA = TLSA
where
LSA = Area of each lagoon, ft^.
A-32.4.7 Calculate total area required.
AT - (TLSA) 2.0
Ml 43,560
where
AT = Total area, acres.
2.0 = Factor to account for >land area between lagoons, buffer space,
storage area, sloping sides of lagoon, etc.
A-32.4.8 Calculate total effective lagoon volume.
TLV = (TLSA) (LD)
where
TLV = Total effective lagoon volume, ft .
A-32.4.9 Calculate accumulation rate of sludge in lagoons.
- VSD) (100)
(TSC) (62.4)
where
SAL = Sludge accumulation rate, ft^/day.
62.43 = Density of water, lb/ftd.
A-32,5 Process Design Output Data
A-32.5.1 Sludge dry solids input to lagoon, DSS, Ib/day.
498
-------
A-32.5.2 Volatile solids input to lagoon, VSS, 1 b/day.
A-32.5.3 Volatile solids destroyed, VSD, 1 b/day.
A-32.5.4 Total lagoon surface area, TLSA, ft .
A-32.5.5 Number of lagoons, NOL.
A-32.5.6 Total area required, AT, acres.
•3
A-32.5.7 Thickened sludge accumulation rate in lagoons, SAL, ft /day.
A-32.6 Quantities Cal cul ations
A-32.6.1 Annual electrical energy required.
E = (NOL) (EUL)
where
E = Annual electrical energy required, kWhr/yr.
EUL = Electrical energy usage for each lagoon, kWhr/yrt determined from
the following table: ,
Electrical
1,000 ft^ of Energy Usage,*
Surface Area/Lagoon EUL (kWhr/yr)
< 44 33,000
44 - 88 50,000
88 - 132 66,000
132 - 176 • 100,000
* Assumes that aerators operate 12 hr/day,
A-32.6.2 Annual operation and maintenance labor requirement, determined
from the following table:
Total Lagoon Vol ume, TLV O&M Labor, L
(ft3) (hr/yr)
200,000 1,600
500,000 1,700
1,000,000 1,800
5,000,000 1,900
10,000,000 2,100
20,000,000 3,000
499
-------
where
L = Total labor, hr/yr (determined from above matrix).
TLV = Total lagoon volume, ft .
A-32.7 Quantities Calculations Output Data
A-32.7.1 Annual electrical energy requirement, E, kWhr/yr.
A-32.7.2 Annual operation and maintenance labor requirement, L, hr/yr.
A-32.8 Unit Price Input Required
A-32.8.1 Current Engineering News Record Construction Cost Index at time
analysis is made, ENRCCI.
A-32.8.2 Current Marshall and Swift Equipment Cost Index at time analy-
sis is made, MSEC I.
A-32.8.3 Cost of land, LANDCST, $/acre. Default value = $3,000/acre.
A-32.8.4 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-32.8.5 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-32.9 Cost Calculations
A-32.9.1 Cost of land for lagoon storage site.
COSTLAND = (AT) (LANDCST)
where
COSTLAND = Cost of land, $.
A-32.9.2 Construction cost of lagoons.
COSTLG = (LG)
where
COSTLS = Construction cost of lagoons, $,
500
-------
LG = Unadjusted construction cost of lagoons, a function of total
lagoon volume, is determined from the following table:
Total Effective Lagoon Construction Cost, LG
Volume. TLV (ftj) ($1,000)
200,000 35
500,000 68
1,000,000 '. 120
2,000,000 200
5,000,000 450
10,000,000 870
20,000,000 1,700
A-32.9.3 Cost of aeration/mixing equipment.
COSTAM, = (AM) (NOL)
where
COSTAM = Cost of aeration/mixing equipment, $.
AM Unadjusted purchase and installation cost for aeration-mixing
equipment, a function of lagoon surface area, is determined from
the following table:
Purchase and
Lagoon Surface Acea, LSA Installation Cost, AM
(1.000 ft1) ($1,000)
< 44 35
44-88 40
88 - 132 45
132 - 176 50
A-32.9.4 Annual cost of operation and maintenance labor.
COSTLB = (TL) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
501
-------
A-32.9.5 Annual cost of electrical energy.
COSTEL = (E) (COSTE)
where
COSTEL = Annual cost of electrical energy, $/yr.
A-32.9.6 Annual cost of replacement parts and materials.
COSTPM = (0.02) (COSTLG)
where
COSTPM = Annual cost of replacement parts and materials, $/yr.
0.02 = Annual replacement parts and materials are estimated at 2
percent of total construction cost of lagoons.
A-32.9.7 Total base capital cost.
TBCC = COSTLANO + COSTLS + COSTAM
where
TBCC = Total base capital cost.
i
A-32.9.8 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTPM
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-32.10 Cost Calculations Output Data
A-32.10.1 Cost of land for lagoon storage site, COSTLAND, $.
A-32.10.2 Construction cost of lagoons, COSTLG, $.
A-32.10.3 Cost of aeration/mixing equipment, COSTAM, $.
A-32.10,4 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-32.10.5 Annual cost of electrical energy, COSTEL, $/yr.
502
-------
A-32,10.6 Annual cost of rep! acement parts and materials, CQSTPM, $/yr.
A-32.10.7 Total base capital cost for lagoon storage process, TBCC, $.
A-32.10.8 Total annual operation and maintenance cost for lagoon storage
process, COST CM,1 $/yr.
503
-------
APPENDIX A-33
SLUDGE STORAGE - ENCLOSED TANK
A-33.1 Background
Storage tanks are usually mixed to maintain a homogeneous mixture, unless
they are used for thickening or decanting. All enclosed tanks should be
equipped to handle the odorous and potentially'toxic and explosive gases that
may be generated during storage.
The following algorithm may be used to obtain costs for either above-
ground or buried tanks. Aboveground tanks are constructed of reinforced con-
crete, whereas buried tanks are constructed of steel. Additional design
assumptions include the following:
* Hydraulic mixing by recircul ation pumping to prevent solids settling
and to provide homogeneous conditions in the tank.
* Low-pressure gas connection to anaerobic digester or other process.
The costs of gas handling and treatment are not included.
* Flame traps at all connections above the liquid level.
« Vacuum rel ief.
Base capital costs include the installation and construction of tanks and
appurtenances as specified above. Costs do not include sludge transfer facil-
ities or costs for transporting sludge to and from the storage tanks. Base
annual O&M costs include labor, electrical energy, and replacement parts and
materials.
A-33.1.1 Al gori thm Devel opment
Capital costs and O&M requirements in this algorithm were obtained from
information supplied by manufacturers and from past facility designs. Addi-
tional information was obtained from in-house documents provided by Gulp/
Wesner/Culp Consulting Engineers.
A-33.2 Input Data
A-33.2.1 Daily sludge volume, SV, gal/day.
A-33.2.2 Number of storage days required at daily sludge flow, SO, days.
A-33.2.3 Mixing energy, ME, hp/1,000 ft3 of tank volume.
504
-------
A-33.2.4 Total dynamic head at mixing pump, TDH, ft.
A-33.2.5 Mixing pump efficiency, EF, dimension!ess.
A-33.2.6 Type of storage tank: below-ground steel tank storage, BGS, or
aboveground reinforced concrete storage, AGS.
A-33.3 Design Parameters
A-33.3.1 Daily sludge volume, SV5 gal/day. This input value must be
provided by the user. No default value.
A-33.3.2 Number of storage days required at daily sludge volume, SD,
days. This input value must be provided by the user. No
default value.
o
A-33.3.3 Mixing energy, ME,, hp/1,000 ftj of tank volume. Default value
= 0.3 hp/1,000 ff3 of tank volume.
A-33.3.4 Total dynamic head, TDH, ft. TDH is a function of tank depth
and friction loss in the piping, pipe fittings, and pump.
Default value = 25 ft.
A-33.3.5 Mixing pump efficiency, EF. Default value = 0.7.
A-33.3.6 Type of storage desired: below-ground storage, BGS, or above-
ground storage, AGS. Default value = AGS.
A-33.4 Process Design Cal culations
A-33.4.1 Calculate storage tank volume.
TV - (SV) (SD)
where
TV = Tank volume, gal.
A-33.4.2 Calculate mixing power required.
MP =
(7.48) (1,000)
where
MP = Mixing power, hp.
o
7.48 = Conversion factor, gal/ft .
1,000 = Conversion factor to convert mixing energy, ME, from hp/1,000 ft3
to hp/ft3-
505
-------
A-33.4.3 Calculate mixing ipump capacity.
(MP) (33.000)
where
MC = Mixing pump capacity, gal /mi n.
33,000 = Conversion factor, hp to ft-lb/min.
8.34 = Density of water, Ib/gal .
A-33.5 Process Design Output Data
A-33.5.1 Storage tank volume, TV, gal.
A-33.5. 2 Mixing power required, MP, hp.
A-33.5. 3 Mixing pump capacity, MC, gal/min.
A-33.6 Quantities Calculations
A-33.6.1 Annual electrical energy requirement. Electrical energy for
mixing is a function of sludge tank volume and related mixing
power.
E = (MP) (0.7457) (8,760)
where
E = Annual electrical energy requirement, kWhr/yr.
0.7457 = Conversion factor, hp to kW.
8,760 = Hours per year of operation, hr/yr.
A-33.6. 2 Annual operation and maintenance labor requirement. Operation
and maintenance labor is a function of storage tank volume.
Storage Tank Volume, TV O&M Labor, L
(1.000 gal) (hr/yr)
10 700
50 1,000
100 1,200
500 1,800
1,000 2,000
t
where
L = Total labor, hr/yr.
506
-------
A-33.7 Quantities Calculations Output Data
A-33,7.1 Annual electrical energy requirement, E, kWhr/yr.
A-33.7.2 Annual operation and maintenance labor requirement, L, hr/yr.
A-33.8 Unit Price Input Required
A-33.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI. :
A-33.8.2 Current Marshall and Swift Equipment Cost Index, MSECI.
A-33.8.3 Cost of electrical energy, COSTE, $/kWhr. Default value =
$0.09/kWhr (ENRCCI/4,006).
A-33.8.4 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006), ;
A-33.9 Cost Calculations
If aboveground storage is specified, proceed to Subsection A-33.9.2.
A-33.9.1 Construction cost of below-ground storage tanks.
COSTBGS = (BGS)
where
COSTBGS = Construction cost of below-ground storage, $.
BGS = Unadjusted cost of below-ground storage, $. This value should
be obtained from the following table:
Dimensions (ft)
Capacity, TV
(1,000 gal)
10
50
100
500
1,000
Length
11 :
18
26
58
82
Width
11
18
26
58
82
Depth
12
20
20
20
20
Construction Cost,
BGS ($1,000)
49
80
137
330
616
A-33.9.2 Construction cost of aboveground storage tanks. If below-
ground storage is specified, proceed to Subsection A-33.9.3.
COSTAGS = (AGS) j^jj^
507
-------
where
COSTAGS = Cost of aboveground storage, $.
A6S = Unadjusted cost of aboveground storage, $. This value should
be obtained from the following table:
Dimensions (ft)
Capacity, TV Construction Cost,
(1,000 gal) Piameter Height AGS ($1.000)
10 12 12 35
50 19.6 24 70
100 23.5 32 106
500 52 32 200
1,000 74 32 313
A-33.9.3 Cost of hydraulic mixing by recirculation.
COSTHM = (HM) (M-jlv--)
where
COSTHM = Cost of hydraulic mixing pump station, $.
HM = Unadjusted cost of hydraulic mixing pump station, $. This
value should be obtained from the following table:
Mixing Pump Capacity, MC Construction Cost, HM
(gal/mi n) ($1.000)
20 17.3
100 23.5
350 31.2
500 35.5
700 42.3
2,000 55.0
3,500 70.5
5,000 87.0
10,000 125.0
A-33.9.4 Annual cost of operation and maintenance labor.
COSTLB - (L) (COSTL)
508
-------
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
A-33.9.5 Annual cost of electrical energy.
COSTEL - (E) (COSTE)
where -.
COSTEL = Annual cost of electrical energy, $/yr.
A-33.9.6 Annual cost of replacement parts and materials.
COSTPM = (0.03) (COSTHM)
where
COSTPM = Annual cost of replacement parts and material, $/yr.
0.03 = Annual cost of replacement parts and materials, expressed as a
percentage of pump capital cost.
A-33.9.7 Total base capital cost.
TBCC = COSTB6S (or COSTAGS) + COSTHM
where
TBCC - Total base capital cost.
A-33.9.8 Total annual operation and maintenance cost.
COSTOM = COSTLB + COSTEL + COSTPM
where ;
COSTOM = Total annual operation and maintenance cost, $/yr.
A-33.10 Cost Calculations Output Data
A-33.10.1 Construction cost of buried storage tank, COSTBGS, $.
A-33.10.2 Construction cost of aboveground storage tank, COSTAGS, $.
A-33.10.3 Cost of hydraulic mixing pump station, COSTHM, $.
509
-------
A-33.10.4 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-33.10.5 Annual cost of electrical energy, COSTEL, $/yr.
A-33.10.6 Annual cost of replacement parts and materials, COSTPM, $/yr.
A-33.10.7 Total base capital cost of sludge storage tank, T8CC, $.
A-33.10.8 Total annual operation and maintenance cost of sludge storage
tank, COSTOM, $/yr.
510
-------
APPENDIX A-34
UNCONFINED PILE STORAGE OF DEWATERED SLUDGE
A-34.1 Background
The term "dewatered sludge" covers a wide range of sludge solids concen-
trations, ranging from approximately 15 percent solids to more than 60 percent
solids. In addition, the extent to which the dewatered sludge has been sta-
bilized varies greatly, ranging from anaerobically digested sludge with high
volatile solids content (e.g., 50 percent) to cured composted sludge with low
volatile solids content (e.g., below 20 percent). Because of the wide range
of characteristics defined by the term dewatered sludge, adequate storage of
such sludge is achieved through the use of a number of techniques, e.g.,
enclosed tanks and hoppers, unconfined piles, or lagoons.
Dry sludge (e.g., over 50 percent solids), such as is often produced by
heat drying, air drying, and temperature conversion processes, is easily
stored using dry materials handling techniques. Dry sludge at treatment
plants or land application sites is usually stored in unconfined piles. In
high rainfall areas the unconfined piles may be covered (e.g., with plastic
sheets) and drainage control provided (e.g., storage site grading and runoff
collection structures). One or more skip loaders can be used to build the
unconfined piles and load sludge haul vehicles.
Dewatered sludge which is relatively high in moisture content (e.g., 15
to 40 percent solids), and still high in volatile organic matter, is difficult
to store in unconfined piles for a period of more than a few days. Odors
develop from decomposition of the organic matter and the unconfined piles
rapidly lose their shape. Rainfall accelerates the erosion process. Long-
term storage for such "wet" sludge is usually done in sludge lagoons, or
occasionally in confined structures. Cost algorithms for facultative sludge
storage lagoons and/or sludge storage tanks are presented in Appendices A-32
and A-33, respectively.
This process covers the cost of unconfined storage of dry or composted
sludge (e.g., over 50 percent solids) in built-up piles. Costs include a
concrete slab, drainage control structures, and one or more skip loaders to
build the unconfined piles and load sludge haul vehicles. This type of
storage facility is generally provided at treatment plants where long-term
storage of dry sludge is necessary. When dry sludge is stored for short
interim periods at a land application site, the sludge is often simply dumped
on the ground in an area where no concrete slab or permanent drainage control
structures are constructed.
511
-------
A-34.1.1 Algorithm Development
Construction costs in the following algorithm were based on information
obtained from construction cost guides (2, 3). O&M requirements are based on
design equations and additional information provided in Reference 4, pages 15-
56 through 15-58. :
A-34.2 Input Data
A-34.2.1 Daily sludge volume, SV, gal/day.
A-34.2.2 Dewatered sludge solids concentration, SS, percent. If SS is
less than 40 percent, it is normally not feasible to use
unconfined pile storage.
A-34.2.3 Period of storage required, SP» days.
A-34.2.4 Storage pile cross section area, X, ft*%
A-34.3 Design Parameters
A-34.3.1 Daily sludge volume, SV, gal/day. This input value must be
provided by the user. No default value.
A-34.3.2 Oewatered sludge solids concentration, SS, percent. This input
value must be provided by the user. No default value.
A-34.3.3 Period of storage required, SP, days. Default value = 180
days.
A-34.3.4 Storage pile cross section area, X, ft . Default value = 32
ft . Algorithm assumes an equilateral triangle cross section.
A-34.4 Process Design Calculation
A-34.4.1 Calculate volume of dewatered sludge to be stored.
(202)
where
SVCY = Sludge volume to be stored, yd3.
202 = Conversion factor, gal/yd3.
A-34.4.2 Calculate storage area required in acres.
TA =
JSVCY) (27) (2)
(3)0'25 (X)0*5 (43,560)
512
-------
where
TA = Storage area required., acres.
27 = Conversion factor, ft3/yd .
2 = Factor to account for spacing between storage piles.
X - Storage pile cross-sectional area, ft .
43,560 = Conversion factor, ft^/acre.
A-34.5 Process Design Output Data
A-34.5.1 Volume of dewatered sludge to be stored, SVCY, yd3.
A-34.5.2 Storage area required, TA, acres.
A-34.6 Quantities Cal cul atioris
A-34.6.1 Number of skip loaders required. For all but very large
treatment plants, one skip loader will suffice to build the
storage piles and load the sludge haul vehicles. This
algorithm assumes that the number of skip loaders is a function
of daily si udtje volume generated and that the skip loader can
handle 30 yd /hr of dewatered sludge (two steps: building
piles and loading into vehicle).
NSL =
(SP) (30) (8) (0.8)
where
NSL = Number of skip loaders required (round to next highest integer).
30 = Skip loader sludge handling capacity, yd^/hr.
8 = Hours in working day.
0.8 = An efficiency factor.
A-34.6.2 Annual diesel fuel requirement. Fuel requirement for the skip
loader is a function of the hr/yr that the skip loader(s) is in
use, which is a function of the yd3 of dewatered sludge to be
handled.
FII - (SVCY) (3) (365)
ru - (SP) (30)
(SP) (30)
t
where
FU = Annual fuel usage, gal/yr.
3 = Annual fuel consumption rate for skip loader, gal/hr.
365 = Days/yr.
30 = Skip loader sludge handling capacity, ydd/hr.
A-34.6.3 Annual operation and maintenance labor requirement. Annual
operation and maintenance labor requirement is assumed to be a
function of the yd3 of dewatered sludge handled.
513
-------
i (SVCY) (365)
L " (SP) (30) (0.7)
where
L = Annual operation and maintenance labor requirement, hr.
365 = Days/yr.
30 = Sludge handling rate, ycr/hr.
0.7 = Efficiency factor.
A-34.7 Quantities Calculations Output Data
A-34.7.1 Number of skip loaders required, NSL.
A-34.7.2 Annual diesel fuel requirement, FU, gal/yr.
A-34.7.3 Annual operation and maintenance labor requirement, L, hr/yr.
A-34.8 Unit Price Input Required
A-34.8.1 Current Engineering News Record Construction Cost Index,
ENRCCI, at time cost analysis is made.
A-34.8.2 Current Marshall and Swift Equipment Cost Index, MSEC I, at time
cost analysis is made,
A-34.8.3 Cost of skip loader, COSTSL, $. Default value = $45,000
(MSECI/751).
A-34.8,4 Cost of concrete slab, COSTS, $/acre. Default value =
$80,000/acre (ENRCCI/4,006).
A-34.8.5 Cost of drainage control structures, COSTD, $/acre. Default
value = $20,000/acre (ENRCCI/4,006).
A-34.8.6 Cost of land, LANDCST, $/acre. Default value = $3,000/acre
(ENRCCI/4,006).
A-34.8.7 Cost of Diesel Fuel, COSTDF, $/gal. Default value = $1.30/gal
(ENRCCI/4,006).
A-34.8.8 Cost of labor, COSTL, $/hr. Default value = $13.00/hr
(ENRCCI/4,006).
A-34.9 Cost Cal culations
A-34.9.1 Capital cost of skip loaders.
TCOSTSL = (NSL) (COSTSL)
where
TCOSTSL = Capital cost of skip loaders required, $.
514
-------
A-34.9,2 Cost of concrete slab.
TCOSTS = (TA) (COSTS)
where
TCOSTS = Cost of concrete; slab, $.
A-34.9,3 Cost of drainage control structures.
TCQSTD « (TA) (COSTD)
where
TCOSTD = Cost of drainage control structures, $.
A-34.9.4 Cost of land.
COSTUND - (TA) (1.2) (LANDCST)
where
COSTLAND = Total cost of land required, $.
1.2 = Factor to account for additional land required for buffer
space, equipment storage, etc.
A-34.9.5 Annual cost of diesel fuel.
COSTFL = (FU) (COSTDF)
where
COSTFL = Annual cost of diesel fuel, $/yr.
A-34.9.6 Annual cost of operation and maintenance labor.
COSTLB - (L) (COSTL)
where
COSTLB = Annual cost of operation and maintenance labor, $/yr.
515
-------
A-34.9.7 Annual skip 1oader maintenance cost.
SLMC = (TCOSTSL) (0.10)
where
SLMC = Annual skip loader maintenance cost, $.
0.10 = Estimated annual maintenance cost of 10 percent of purchase price.
A-34.9,8 Total base capital cost.
TBCC = TCOSTSL + TCOSTS + TCOSTD + COSTLAND
where
TBCC = Total base capital cost, $.
A-34.9.9 Total annual operation and maintenance cost.
COSTOM = COSTFL + COSTLB + SLMC
where
COSTOM = Total annual operation and maintenance cost, $/yr.
A-34.1Q Cost Calculations Output Data
A-34.10.1 Capital cost of skip loaders required, TCOSTSL, $.
A-34.10.2 Cost of concrete slab, TCOSTS, $.
A-34.10.3 Cost of drainage control structures, TCOSTD, $.
A-34.10,4 Cost of land, COSTLAND, $.
A-34.10.5 Annual cost of diesel fuel, COSTFL, $/yr.
A-34.10.6 Annual cost of operation and maintenance labor, COSTLB, $/yr.
A-34.10.7 Annual cost of skip loader maintenance, SLMC, $/yr.
A-34.10.8 Total base capital cost of unconfined pile storage, TBCC, $.
A-34.10.9 Total annual operation and maintenance cost of unconfined pile
storage, COSTOM, $/yr.
516
-------
APPENDIX A-35
REFERENCES
1. Harris, R. W. , M. J. Cul inane, Or., and P. T. Sun, eds. Process Design
and Cost Estimating Algorithms for the Computer Assisted Procedure for
Design and Evaluation of Wastewater Treatment Systems (CAPDET). Final
Report. Army Engineer Waterways Experiment Station, Vicksburg, Missis-
sippi, and Environmental Protection Agency, Washington, D.C., Office of
Water Program Operations, January 1982. 729 pp. (Available from NTIS as
PB82-190455. )
2. Building Construction Cost Data 1983. 41st Annual Edition. R. S. Means
Company, Kingston, Massachusetts, 1982. 436 pp.
3. McGraw-Hill's 1983 Dodge ; Guide to Public Works and Heavy Construction
Costs. Annual Edition No. 15. McGraw-Hill Information Systems Company,
Princeton, New Jersey, 1982.
4. Process Design Manual for Sludge Treatment and Disposal. Technology
Transfer Series. EPA-625/1-79-011, Center for Environmental Research
Information, Cincinnati, Ohio, September 1979. 1135 pp. (Available from
NTIS as PB80-200546. ) :
5. Zimpro Environmental and Energy Systems. Sludge Management Systems
Manual. Rothschild, Wisconsin, 1984. 158 pp.
6. Process Design Manual for Dewatering Municipal Wastewater Sludges. EPA-
625/1-82-014, Center for Environmental Research Information, Cincinnati,
Ohio, October 1982. 222 pp.
7. Innovative and Alternative Technology Assessment Manual. Technical
Report. EPA-430/9-78-009, EPA/MCD-53, Environmental Protection Agency,
Washington, D.C., Municipal Construction Division, February 1980. 471
pp. (Available from NTIS as PB81-103277.)
8. Eckenfelder, W. W., Jr., and J. S. Chakra, eds. Sludge Treatment. Mar-
cel Dekker, New York, 1981. 591 pp.
9. Noland, R. F. , and J. D. Edwards. Lime Stabilization of Wastewater
Treatment Plant Sludges. In: Sludge Treatment and Disposal Seminar
Handout. Introduction and Sludge Processing. Prepared for Environmental
Research Information Center, Cincinnati, Ohio, March 1978. 97 pp.
517
-------
10. Verdouw, A. J., E. W. Waltz, and W. Bernhardt. Plant-Scale Demonstration
of Sludge Incinerator Fuel Reduction. EPA-600/2-83-083, Indianapolis
Center for Advanced Research Laboratory, Cincinnati, Ohio, September
1983. 80 pp. (Available from NTIS as PB83-259697.)
11. Ettlich, W. Transport of Sewage Sludge. EPA-600/2-77-216, Cul p/Wesner/
Culp, El Dorado Hills, California, for Municipal Environmental Research
Laboratory, Cincinnati, Ohio, Wastewater Research Division, December
1977. 98pp. (Available from NTIS as PB-278 195.)
12. Construction Costs for Municipal Wastewater Conveyance Systems: 1973-
1979. Technical Report, EPA-430/9-81-Q03, Environmental Protection
Agency, Washington, D.C., Office of Water Program Operations, February
1982. 124 pp. (Available from NTIS as PB82-160482.)
13. Process Design Manual for Land Application of Municipal Sludge. Technol-
ogy Transfer, EPA-625/1-83-016, Center for Environmental Research Infor-
mation, Cincinnati, Ohio, October 1983. 436 pp.
14. Reed, S. C., R. W. Crites, R. E. Thomas, and A. B. Hais. Cost of Land
Treatment Systems. EPA-430/9-75-003, EPA/MCD-10-R, Environmental Protec-
tion Agency, Washington, D.C., Municipal Construction Division, September
1979. 145 pp. (Available from NTIS as PB80-182900.)
15. Gorte, J. K. Cost of Forest Land Disposal of Sludge. Ph.D. Disserta-
tion. Michigan State University, East Lansing, 1980. 204 pp.
16. Caterpillar Tractor Company, Caterpillar Performance Handbook. Edition
6. Peoria, Illinois, January 1976. 662 pp.
17. Process Design Manual: Municipal Sludge Landfills. EPA-625/1-78-010,
Environmental Research Information Center, Cincinnati, Ohio, October
1978. 331 pp. (Available from NTIS as PB-299 675.)
518
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APPENDIX B
ANNOTATED BIBLIOGRAPHY OF SOURCES OF COST INFORMATION
IN THE TECHNICAL LITERATURE
B.I Introduction
This section contains an annotated bibliography of selected cost informa-
tion literature sources for sludge management processes. The sources of
information and the sludge management processes covered in each source are
summarized in Table B-l. In addition, this table presents the year of publi-
cation and the base year of the cost estimates.
In order to utilize the cost estimate information contained in the tech-
nical literature, the reader should be aware of the inherent difficulties in
comparing costs from different sources. Part of these difficulties stem from
the varying methods that authors use in presenting their cost estimates. The
reader should therefore take the following factors into consideration, since
they influence capital construction and operation and maintenance costs from
different literature sources.
(1) Different cost estimating base years. Cost estimates with a base year
of 1980 cannot be directly compared to cost estimates with a base year
of 1984. However, this problem can be overcome by using apropriate cost
indexes such as the Engineering News Record Construction Cost Index.
(2) Different assumptions for certain basic cost factors, such as labor,
electricity, fuel, hours per day of operation, days per year of opera-
tion, etc.
(3) Inclusion or exclusion of land costs. If land costs are included, the
cost per acre may vary widely.
(4) Inclusion or exclusion of administrative and overhead costs. If admin-
istrative/overhead costs are included, the percent cost may vary widely.
This factor primarily affects annual O&M cost estimates.
(5) Inclusion or exclusion of engineering fees, legal fees, administrative
costs, and interest during construction as part of the project construc-
tion cost. These factors can easily add 30 to 40 percent to project
costs. In some rare cases, cost estimates will not include that portion
paid by EPA construction grant funds.
(6) Geographic location. Construction, labor, electricity, etc., costs vary
from region to region. Costs in Oregon may be one-third less than in
New York City for similar projects.
519
-------
TABLE B-1
SUMMARY OF SELECTED COST INFORMATION SOURCES FROM THE TECHNICAL LITERATURE
SOURCE
Anderson. K, , tt «1.
Co it of Undtprtidl ng
ind Hauling Sludge
fro* Nun1clp*t U«jti»
writer IrtttMM P1«ntt,
CM S3Q/SM-619.
Ed1* e^isit.
SvitHit tnd Pr(H«tniF¥
SHt Id «t if lection*
LA/ON* Project.
Clirkt el a] . Digested
$l*3<)t Qewttrfftg tspe-
rtffices it Orange Co^ntj,
CoiyHch, M. F. Iftttn-
eritlon of Sludge ind
flftfuf* -1th Hltt* Ke«t
&ortc, J. IE. Colt of
foreii Lind OUponl
Of Slg^9e.
QuMtrvjiii ct aU 0*ilp
KJinutl Oewatwlng Hunt*
1977
*>H1
l»77
1991
July
1979
1980
ifcl.
I
1974
1976
197.
1917
1979
198J
nuk
Srtvlty
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TABLE B-1 (continued)
SOURCE
leCoftde et al . Process
DeM?n Manual - tftnd
Application of Itinlcl-
p»l Sludge, EP«-6?V1-
83-OU.
lelnlnger el al .
tride-Offt In Sludoe
thickening ana Irani-
port/Reuse Systems.
HcOonal d et al , SI yd$e
Management aRd Energy
Independence.
Hinlclprtltj of Metro-
politan Seattle, sludge
Dllpolll end Keg It Coit-
Kurphy, at il . Open.
tlon and Maintenance
Cottl for Municipal
data at al , Coapott-
i«9 end Olipotil of
SI udge.
Oct.
198)
Nov.
1MO
'rt.
1H1
Dec,
1992
198]
Jan,
1910
a
Wd-
19BII
1978
Mf.
im
1983
rint
Qaafter
Tklck
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1
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o
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i
9
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i
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r
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r
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o
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ca
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f
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ctlin
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l
522
-------
(7) Pollution control standards which must be met. Obviously, more strin-
gent air and water quality emission standards usually result in higher
construction and O&M costs.
(8) Many cost estimates are presented on a present worth or amortized basis.
It is necessary to know what interest rates, facility life, etc.,
assumptions were used.
(9) Size of the sample (i.e., number of facilities) used as a basis for the
cost estimates given. Generally, the larger the sample, the greater the
range of costs reported. '.
(10) Different methods of presenting cost information versus project size.
Referring specifically to municipal wastewater sludge, costs may be pre-
sented as a function of population served, treatment plant size in mgd,
raw wet sludge volume in mgd, stabilized wet sludge volume in mgd, tons
of dry sludge solids, tons of wet sludge, etc.
B.2 Annotated Bibiliography
The following annotated bibliography is organized in the same sequence
as Table B-l. The reader should search for the sludge management process of
interest on Table B-l, find the corresponding literature which has cost infor-
mation on the subject process, and read the annotated reference in order to
find out the types of information that the source contains.
Anderson, R. K., B. W. Meddle, T. Hillmer, and A. Seswein. Cost of Land
Spreading and Hauling Sludge from Municipal Wastewater Treatment Plant. EPA-
530/SW-619, U.S. Environmental Protection Agency, Office of Solid Waste Man-
agement Programs. October 1977. 157 pp.
This report is an analysis of the 1974 cost of. disposing of municipal
wastewater treatment sludge by land spreading. The study is based on a survey
of 24 small communities.
Costs were evaluated for land spreading both liquid sludge and dewatered
sludge. Average 1974 costs, including dewatering (if done), transport, and
land appl ication were as follows:
1. Liquid sludge followed by land application - $32/dry ton.
2. Vacuum filtration followed by land application - $87/dry ton.
3. Sludge drying beds followed by land application - $87/dry ton.
Survey results varied widely, and it is difficult to utilize this 1974 cost
information in estimating costs in 1984 and later.
523
-------
CHoM Hill. Initial Analysis of Candidate Systems and Preliminary Site
Identification: LA/QMA Project. Newport Beach, California, April 1977. 291
pp.
The Los Angeles/Orange County Metropolitan Area (LA/OMA) project was
designed to develop a long-term plan to reuse or dispose of residual solids
resulting from wastewater treatment in the Los Angeles-Orange County metropol-
itan area.
The study included preliminary costs, energy consumption factors, envi-
ronmental and social concerns, implementation capability, process reliability
and flexibility, and effects on public health, land use, and growth. The pre-
liminary cost estimates (both capital and O&M costs) are based on third quar-
ter 1976 (ENR = 2,800). All cost estimates are "order of magnitude" esti-
mates, and are approximate, without benefit of detailed engineering data,
plans, or specifications (+50 percent above; -30 percent below actual costs).
Seventeen representative sludge management schemes were investigated. These
schemes combined various methods of sludge thickening, stabilization, dewater-
ing, drying, incineration, transport, and disposal/reuse methods. While the
report is specific to the greater Los Angeles/Orange County area of southern
California, it contains cost information which may be helpful to other major
urban areas.
Clarke, W. N., W. Fox, and W. R. Howard. Digested Sludge Dewatering
Experiences at Orange County, California. J. Water Pollut. Control Fed.,
53:530-535, 1981.
The County Sanitation Districts of Orange County (CSDOC) collects,
treats, and disposes of 195 mgd of wastewater, 25 percent of which is indus-
trial. Sludge is stabilized by anaerobic sludge digestion, then dewatered in
centrifuges, air-dried, and sold to a contractor for use as a soil supplement,
or disposed to a sanitary landfill.
CSDOC conducted a cost evaluation to determine whether primary and sec-
ondary sludges should be dewatered separately or whether they should be com-
bined prior to treatment. In both cases, it was assumed that polymer would be
added to improve dewatering. No cost curves are presented.
The article contains representative operating costs (1980) for six cen-
trifuges on line (four actual operating, two spares), in cost/dry ton pro-
cessed. Costs include cost for polymers, electricity, and equipment mainte-
nance, as follows:
• Maintenance costs - $2.20/dry metric ton.
• Electrical costs - $2.20/dry metric ton.
524
-------
Polymer costs - $10,09/dry metric ton for primary digested sludge,
and $21.91/dry metric ton for combination of 70 percent digested pri-
mary sludge, 30 percent digested waste activated sludge.
Cosulich, W. F. Incineration of Sludge and Refuse with Waste Heat Recov-
ery. J. Water Pollut. Control Fed., 51:1934-1938, 1979.
This article describes development of an incineration project to co-burn
refuse and wastewater sludge at Glen Cove, New York.
Co-burning systems evaluated were:
O
t Pyrolysis (heat value - 350 Btu/ft0) - Small capacity makes pyrolysis
systems economically unfeasible.
• Fluidized bed incineration - Preliminary cost figures indicate no
economic advantage.
• Stoker-fired incinerator - Designed with 30-min detention time.
The proposed stoker-fired incinerator system consists of flotation thickeners,
aerated storage tanks, centrifuges for dewatering, and a refuse incinerator
(250 tons/day). The estimated heat value was determined to be 4,550 Btu/1 b.
Estimated project cost for this system in 1977 was $30 million.
Gorte, J. K. Cost of Forest Land Disposal of Sludge. Ph.D. Disserta-
tion. Michigan State University, East Lansing, 1980. 204 pp.
This doctoral dissertation evaluates economics of sludge application to
forest land. Technologies available for application, costs, and sensitivity
of costs to changes in variables are tested. A simple simulation model
(SLUDGE) was used for cost estimating various methods, and incorporates trans-
portation, land application, and ground monitoring cost elements.
Conclusions of the study:
• Transportation is the largest component of disposal cost.
• For any mode of transportation, increasing haul distance causes
transport cost to escalate.
• Rail and barge transport costs are fairly competitive with each
other, and these methods (if feasible) are less expensive to handle
long-distance transport of large sludge volumes than trucks.
525
-------
• Pipeline transport of liquid sludge is the most cost-effective means
of moving large volumes of sludge long distances.
• Spray irrigation is a cheaper liquid sludge application method than
either surface or subsurface vehicular application.
• Transportation and application of dewatered sludge are less expensive
than transportation and application of liquid sludge, on a per dry
ton basis. The cost of dewatering sludge must be weighed against
this disposal cost advantage.
This dissertation contains interesting cost information, but is based upon
many grossly simplifying assumptions which decrease its usefulness for esti-
mating "real life" costs at specific treatment plants.
Gumerman, R. C., and B. E. Burn's. Process Design Manual for Dewatering
Municipal Wastewater Sludges. EPA 625/1-82-014. Culp/Wesner/Culp, Santa Ana,
California. October 1982. 221 pp.
This manual is a review of municipal wastewater sludge dewatering process
technology, to facilitate the selection and design of a dewatering process.
Included are discussions of sludge characteristics, dewatering processes,
their performance capabilities and operational variables, chemical condition-
ing, cost and energy considerations, and case study information.
Dewatering processes discussed are basket centrifuge, 1 ow 6 and high 6
solid bowl centrifuge, belt filter press, vacuum filter, fixed-volume and
variable-volume recessed plate filter press, drying bed, sludge lagoon, and
gravity/low-pressure devices.
Construction and O&M cost curves are presented for nine dewatering pro-
cesses. Construction costs are for installed equipment, and include all con-
crete structures, housing, pipes and valves, electrical and instrumentation
equipment, and installation labor. O&M requirements and costs are presented
for labor, building electrical, process electrical, diesel fuel, and mainte-
nance materials.
Cost analyses were made for three sizes of sludge handling systems: 1,
5, and 50 tons/day of dry sludge solids (approximately equal to 1, 5, and 50
mgd wastewater treatment capacity). Costs are updated to April 1982, and are
increased by 40 percent to account for engineering, contingencies, contrac-
tor's overhead and profit, legal fiscal and administrative, and interest dur-
ing construction. Land costs were included at $2,000/acre. Capital costs
were amortized at 10 percent for 20 years. Trucks, composting equipment, and
front-end loaders were amortized at 10 percent over 8 years.
526
-------
LaConde, K. V., C. J. Schmidt, H. Van Lam, T. Boston, and T. Dong. Pro-
cess Design Manual for Land Application of Municipal Sludge. EPA-625/1-83-
016, SCS Engineers, Long Beach, California, October 1983. 434 pp.
This is a design manual which details the planning and design of munici-
pal wastewater sludge application to cropland, forest land, marginal (dis-
turbed) land, and dedicated disposal sites. Cost information is limited, but
includes cost tables for sludge transport trucks, pipelines, and land applica-
tion site improvements (e.g., fences, grading, etc.). Cost estimates are
based on mid-1980 costs.
Leininger, K. V., P. L. Nehm, and J. W. Schellpfeffer. Trade-Offs in
Sludge Thickening and Transport/Reuse Systems. J. Water Pollut. Control Fed.,
52:2771-2779, 1980.
This study was specific to the Madison, Wisconsin, solids reuse pro-
gram. Present treatment in Madison is accomplished by a 50-mgd sewage treat-
ment plant, consisting of primary treatment, activated sludge, gravity thick-
ener, and two-stage anaerobic digestion. The proposed solids handling scheme
was thickening, digestion, transport, and land application. Two alternative
thickening methods were examined: flotation thickening and centrifugation
thickening. A third variable was to vary the digestion time.
Cost curves were developed for sludge thickening, digestion, transport,
and reuse facilities. Curves were derived for both capital and annual opera-
tion and maintenance cost, based on 1978 dollars. Capital costs were annual-
ized using a 6.625 percent rate.
The study concluded that additional thickening by flotation or centri-
fugation was not cost effective for Madison, Wisconsin. Continuation of the
existing gravity thickening process was the most economical alternative prior
to agricultural reuse.
Otoski, R. M. Lime Stabilization and Ultimate Disposal of Municipal
Wastewater Sludges. EPA 600/2-81-076. U.S. Environmental Protection Agency,
Municipal Environmental Research Laboratory, June 1981. 191 pp.
This report demonstrates the successful use of lime in stabilizing sludge
from 28 municipal wastewater treatment plants in New England and New York. In
general, lime stabilization was found to be an attractive alternative for
treatment plants with wastewater flows of less than 6 mgd due to two factors.
First, process costs are operation and maintenance (O&M) intensive rather than
capital intensive. Second, the costs of chemicals, the major portion of the
total cost, shows little economy of scale.
527
-------
Cost curves, including both construction and O&M costs, are presented for
a batch operation for sewage plant flows between 1 and 5 mgd. In addition,
cost curves for converting and using existing lime-conditioning equipment for
operation in lime stabilization are presented.
McDonald, S. C., T. Quinn, and A. Jacobs. Sludge Management and Energy
Independence. J. Water Pollut. Control Fed., 53:190-200, 1981.
Monroe County, New York (pop. 430,000) utilizes activated sludge for
treatment of municipal wastewater. The treatment plant processes an average
of 90 mgd.
Sludge treatment consists of thickening of primary and secondary solids
by gravity, dewatering by five vacuum filters, followed by incineration in
three multiple-hearth furnaces. The generated ash is pumped into lagoons for
disposal. The municipality processes 60 tons of dry solids daily.
Three alternatives were developed for disposal of the sludge:
• Direct land application.
• Composting to produce a soil conditioner.
• Thermal reduction techniques.
The alternatives were screened on the basis of equivalent annual cost over a
20-year planning period.
The most cost-effective sludge management alternative was determined to
be replacement of four vacuum filters with continuous belt filter presses;
modification of two multiple-hearth furnaces for starved air combustion, with
provision for the addition of refuse-derived fuel to the two large furnaces,
and addition of waste heat boilers and steam turbines for electrical power
generation.
The sludge handling system was evaluated, assuming a total dewatering
capacity of 180 tons/day, and a furnace capacity of 181 tons/day.
Municipality of Metropolitan Seattle. Sludge Disposal and Reuse Cost-
Effectiveness Evaluation, Technical Memorandum. Seattle, Washington, December
1982. 113 pp.
The City of Seattle developed detailed studies of alternative methods to
manage the sludge generated by Its sewage treatment plants. Evaluations
included alternative methods (and costs) for in-plant sludge processing,
transportation, and reuse/disposal.
528
-------
The following eight disposal and reuse alternatives were evaluated:
1. Agricultural use.
2. Composting.
3. Dry sludge product.
4. Incineration.
5. Landfill ing.
6. Ocean disposal.
7. Silviculture.
8. Soil improvement.
In addition to costs, each alternative was evaluated in terms of energy use,
air emissions, soil impacts, ground water impacts, surface water impacts, pub-
lic health impacts, wildlife impacts, land availability, land use impacts,
community acceptance, agency acceptance, proven experience, flexibility, fed-
eral and state legislation, and imp! ementabil ity.
Cost estimates are specific to the City of Seattle, but their methods of
development may be of interest to other large urban areas.
Murphy, R, S., M. W. Hall, and W. H. Huang. Operation and Maintenance
Costs for Municipal Wastewater Facilities. EPA-430/9-81-004, Sage Murphy &
Associates, Denver, Colorado, September 1981. 136 pp.
This report summarizes O&M cost data for more than 900 wastewater treat-
ment plants and almost 500 sewage conveyance systems. Included is information
on administrative costs, sludge handling costs, and staffing. Data were ob-
tained from a 1978 EPA report on individual wastewater treatment plants. In
addition, technical literature was reviewed. The data represent costs re-
ported during the period from 1973 to 1978. Only facilities with secondary or
higher levels of treatment are included. Lagoonal treatment systems were
excluded. Cost information is updated using indexes and is expressed as First
Quarter 1981 dollars (unless noted).
In general, sludge management O&M costs are expressed in dollars per year
versus treatment plant wastewater flow in mgd. O&M cost categories include
labor, power, utilities, chemicals, and administration. Relatively little
specific information is presented for individual sludge treatment and dis-
posal/reuse processes.
529
-------
Nese, P. A., 0. Salandak, and J. A. Frederick. Composting and Disposal
of Industrial Wastewater Sludge. J. Water Pollut. Control Fed., 52:183-191,
1980.
This article summarizes sludge management alternative plans prepared by
the Linden Resell e Sewerage Authority, New Jersey, for its treatment plant and
two adjacent sewerage agencies. Alternatives evaluated were:
• Pyrolysis.
• Land application of digested sludge to cropland.
• Composting followed by land application.
The study is very specific to the treatment plants studied, but contains
interesting cost information pertinent to the processes considered. The
sludge was too high in metal content for use on agricultural land. Other
(1979 base year) cost estimates were:
• Composting - $123/dry ton.
• Pyrolysis - $169/dry ton.
Rimkus, R. R., E. W. Knight, and G. E. Sernel. Solids Handling Systems
for Six Different Disposal Options. J. Water Pollut. Control Fed., 52:740-
749, 1980.
The Metropolitan Sanitary District of Greater Chicago (MSDGC), which
serves 5.5 million people, collects 700 tons/day of organic solids. In 1977,
MSDGC generated 867 tons/day of dry sludge solids.
The disposal management options which were considered by MSDGC are:
1. Nu Earth giveaway - digested, dried sludge.
2. Heat-dried fertilizer sale - gravity settling, vacuum filtration,
drying.
3. Heated digestion followed by land application (to Fulton County).
Secondary solids and a small amount of primary solids are digested
anaerobically for 14 days, pumped into barges, and taken to a land
reclamation site (strip mine).
4. Heated digestion followed by lagoon aging and free distribution.
Digested solids are stored in large holding basins, dewatered,
trucked, and applied to land.
5. Heated digestion followed by lagooning and solids disposal. Removal
is accomplished on a competitive bid basis.
6. Composting followed by free distribution.
530
-------
Comparative costs shown be! ow are for solids stabilization, processing, and
disposal. These costs do not include capital costs, only O&M and transport/
distribution costs.
; $/Dry Metric Ton
Method Distributed
Nu Earth ', 69
Heat-Dried Fertil izer 209
Fulton County 207
Lagoon Solids Distribution 72
Contract Lagoon Cleanout 78
Composting 234-308
Wall is, I. G. Ocean Outfall Construction Costs. G. Water Pollut. Con-
trol Fed., 51:951-957, 1979.
This article provides cost and design information on 36 outfalls on the
west coast of the United States, three in Hawaii, and one in Puerto Rico. The
ENR index was used to convert all costs to a common basis (ENR is 3,200).
Data on installed and projected ocean outfalls were obtained from three
sources: outfall owners, consulting engineers, and contractors.
It was concluded that the two major factors influencing unit construction
cost are construction conditions and the diameter of the outfall. The outfall
length was a less significant factor.
Local conditions which were found to affect cost significantly are seabed
conditions, ease of site access, haulage distances, available hydraulic head,
attitude and commitments of contractors at time of bids, and degree of protec-
tion against turbulent water conditions.
While the unit cost relationships presented here can give an approximate
estimate of the projected cost of constructing an outfall, a detailed estimate
based on a specific outfall design and local circumstances is needed to obtain
an accurate estimate. :
U.S. Environmental Protection Agency, Center for Environmental Research
Information. Process Design Manual for Sludge Treatment and Disposal. EPA-
625/1-79-011, Cincinnati, Ohio, September 1979. 1135 pp.
This excellent design manual deserves a place on every treatment plant
design engineer's shelf. It contains a wealth of design information for
531
-------
virtually every sludge treatment process. However, it is weak in its coverage
of sludge transport and recycle/disposal options.
Cost information is scattered throughout the manual. Base years for cost
data vary from 1975 to 1978.
U.S. Environmental Protection Agency, Municipal Construction Division.
Innovative and Alternative Technology Assessment Manual; Technical Report.
EPA-430/9-78-009, Washington, D.C., February 1980. 471 pp.
This manual was prepared to provide guidance in applying for Innovative
and Advanced (I and A) construction grant increases from 75 to 85 percent.
Appendices to the manual summarize wastewater treatment and sludge management
processes, including cost curves for construction and O&M cost estimating.
The base year for cost estimates is 1976.
Typical of basic cost factors used are the following:
ENR index = 2,475 (September 1976).
Labor, including fringe benefits = $7.50/hr.
Electrical power = $0.02/kWhr.
Fuel oil = $0.37/gal •
Gasoline = $0.60/gal.
Land cost = $l,000/acre.
Sludge processes included in the manual are as follows:
Centrifugal dewatering.
Centrifugal thickening.
Composting, static pile.
Composting, windrow.
Filter press.
Dewatered sludge truck transport.
Dewatered sludge rail transport.
Digestion, aerobic.
Digestion, two-stage anaerobic.
DAF thickening.
Drying beds.
Belt press filter.
Heat treatment of siudge.
Incineration, fluidized bed.
Incineration, multiple hearth.
Lagoon, facultative.
Land application of sludge.
Lime stabil ization.
Liquid sludge transport by pipeline.
Liquid sludge transport by rail.
Liquid sludge transport by truck.
Polymer addition.
532
-------
t Sludge landfill - area method.
t Sludge landfill - trench method.
t Sludge pumping.
• Sludge storage.
• Vacuum filtration.
533
-------
en
CO
APPENDIX C
U.S. CUSTOMARY TO METRIC CONVERSION FACTORS
U.S. Customary Unit
Metric Unit
Name
Acre
British thermal unit
Cubic feet per day
Cubic feet per gallon
Cubic feet per hour
Cubic feet per million
gallons
Cubic feet per minute
Cubic feet per minute per
1,000 cubic feet
Cubic feet per minute per
1,000 gallons
Cubic feet per pound
Cubic feet per second
Symbol
acre
Btu
ft3/day
ft3/gal
ft3/hr
ft3/Mgal
f t3/mi n
1,000 ft3
f t3/mi n/
1,000 gal
ft3/! b
ft3/sec
Multiplier
4.047 x 103
0.047
1.055
1.889 x 10"4
7.482
7.482 x 10"3
7.867 x 10~6
7.482
4.719 x ID"4
1.667 x 10'2
0.1247
6.243 x 10"2
2.832 x 10"2
Name
Square meter
Hectare
Kilojoul e
Cubic meters per second
Unit cubic meter
Cubic meters per liter
Cubic meters per second
Milliliters per cubic meter
Cubic meters per second
Liters per cubic meter per
second
Liters per cubic meter per
second
Cubic meters per kilogram
Cubic meters per second
Symbol
m2
ha
kJ
m3/s
m3/m3
m3/L
•5
m /sec
mL/m3
o
m /sec
L/nr/sec
L/m3/sec
m3/kg
m /sec
-------
APPENDIX C (continued)
U.S. Custernary Unit
Metric Unit
Name
Cubic feet per second per
acre
Cubic feet per second per
square mile
Cubic foot
Cubic inch
en
U1
Cubic yard
Cycles per day
Degrees Fahrenheit -
Feet per day
Feet per hour
Feet per minute
Foot
Foot-pounds per inch
Symbol
o
ft /acre/ sec
ft3/mi2/sec
ft3
in3
yd3
cycl e/day
0 F
ft/day
ft/hr
ft/mi n
ft
ft-lb/in
Multiplier
6.997 x 10~6
1.093 x 10"8
2.832 x 10"2
28.32 •• •-
16.39 x 10'6
16.39
0.7646
1,440
0.5556
(° F - 32)
2.032 x 10-3
8.467 x 10"5
5.08
0.3048
0.3048 x 10"3
1.659
Name
Cubic meters per square meter
per second
Cubic meters per square meter
per second
Cubic meter
Liter
Cubic meter
Milliliter
Cubic meter
Hertz
Degrees Centigrade
Meters per second
Meters per second
Millimeters per second
Meter
Kilometer
Joules per meter
Symbol
nr/nr/sec
m3/m2/sec
m3
L
.3
mL
m3
Hz
0 C
m/sec
m/sec
mm/ sec
m
km
J/m
-------
APPENDIX C (continued)
U.S. Customary Unit
CJI
00
CT>
Name
Foot-pounds per second
Gallon
Gallons per day
Gallons per day per acre
Gallons per day per mile
Gallons per day per square
foot
Gallons per day per 1,000
square feet
Gallons per hour
Gallons per mile
Gallons per minute
Gallons per pound
Gallons per ton
Symbol
ft-lb/sec
gal
gal/day
gal/day/acre
gal /day/mi
Mul ti pi 1_er
1.355
3.785 x 10"3
3.785
4.381 x 10"5
3.785 x 10'3
1,083 x 10"11
9.353
2.72 x 10'11
gal/day/1,000 4.074 x 10
-2
gal/hr
gal /mi
gal /mi n
gal/lb
gal /ton
1.051 x
2.352
6.308 x
8,344
4.173
10'°
ID'5
Metric Unit
Name
Watt
Cubic meter
Liter
Liters per second
Cubic meters per day
Symbol
W
m3
L
L/sec
m3/day
•3 y
Cubic meters per square meter nr/nr/sec
per second
Liters per hectare per day
Cubic meters per meter per
second
gal/day/ft^ 4.715 x 10"^ Meters per second
Liters per square meter per
day
Cubic meters per second
MillilHer per meter
Cubic meters per second
MillHiter per kilogram
Milliliter per kilogram
L/ha/day
q
nr/m/sec
m/sec
L/m2/day
m3/sec
mL/m
m3/sec
tnL/kg
mL/kg
-------
APPENDIX C (continued)
U.S. Cu stoma ry On i t
Metric Unit
CA>
Name
Gallons per year
Hectare
Horsepower
Horsepower-hour
Horsepower per 1,000 cubic,,
feet
Horsepower per 1,000 gallons
Inch • • ' • •'
Kil owatt
Kil owatt-hour
Kilowatt-hours per day
Kilowatt-hours per gallon
Kilowatt-hours per million
gallons
Kil owatt-hours per pound
Kilowatt-hours per ton
Symbol
gal /yr
ha
hp
hp-hr
•hp/1,000 ft3.
hp/1,000 gal
in
kW
kWhr
kWhr/day
kWhr/gal
kWhr/Mgal
kWhr/lb
kWhr/ton
Multipl ier
1.599 x ID'2
1 x 104
745.7
2.685
1,475.9.07..-..
197.3
2.54 x 10'2
25.40
3.6 x 106
1.3596
3.6
41.67
951.1
951.1
7.936 x 10"3
3.969
Name
Liters per second
Square meter
Watt
Mega joule
Killowatts per cubic meter
Kilowatts per cubic meter
Meter.
Millimeter
Joules per hour
Horsepower
Mega joule
Watt
Megajoules per cubic meter
Joules per cubic meter
Megajoules per kilogram
Kilojoules per kilogram
Symbol
L/sec
m2
W
MJ
kW/m3
kW/m3
m
mm
J/hr
hp
MJ
W
-MJ/m3
J/m3
MJ/kg
kJ/kg
-------
APPENDIX C (continued)
U.S. Customary Unit
Metric Unit
Ul
CO
00
Parts per million
Pound (mass)
Pound-foot
Pounds per acre per day
Symbol
kWhr/yr
mi
mi/hr
Name
Kilowatt-hours per year
Mile
Miles per hour
Million gallons
Million gallons per day
Million gallons per day per Mgal/acre
acre
Multiplier
15.2096
1.609
0.4469
1.609
3.785 x 103
3.785
Mgal/day (M6D) 4.383 x 10'2
1.083 x 10'5
9.353
Mgal
ppm
Ib
Ib-ft
Ib/ac re/day
Pounds per cubic foot
b/ftc
1.0
0.4536
1.356
1.297 x 10'9
1.121
16.02
Name Symbol^
Kilowatts per year kW/yr
Kil ometer km
Meters per second m/sec
Kilometers per hour km/hr
Cubic meter m3
Megaliter ML
Cubic meters per second nr/sec
Meters per second m/sec
Megaliters per hectare per ML/ha/day
day
Milligrams per liter mg/L
Kilogram kg
Newton-meter Nm
Kilograms per square meter kg/nr/sec
per second
Kilograms per hectare per kg/ha/day
day
3
Kilograms per cubic meter kg/m
-------
APPENDIX C (continued)
U.S. Customary Un 11
Metric Unit
tn
Name
Pounds per cubic foot per
hour
Pounds per 1,000 cubic feet
Pounds per cubic yard
Pounds per day
Pounds per day per acre
Pounds per day per cubic
foot
Pounds per day per square
foot
Pounds per gallon
Pounds per hour
Pounds per hour per square
foot
Pounds per hour per cubic
foot
Pounds per horsepower-hour
Pounds per million gallons
Pounds per pound
Symbol
Ib/ft3/hr
lb/1,000 ft3
1 b/yd3
1 b/day
1 b/day/acre
1 b/day/f t3
1 b/day/f t2
1 b/gal
Ib/hr
lb/hr/ft2
1 b/hr/ft3
Ib/hp-hr
1 b/Mgal
Ib/lb
Multiplier
4.449 x 10"3
16.02
0.5933
5.25
0.1121
16.02
56.51
0.1198
0.1260
4.882
57.67
2.957
0.1198
1,000
Name
Kilograms per cubic meter
per second
Grams per cubic meter
Kilograms per cubic meter
Milligrams per second
Grams per square meter per
day
Kilograms per cubic meter
per day
Milligrams per square meter
per second
Kil ograms per liter
Kil ograms per second
Kilograms per square meter
per hour
Kilograms per liter per
second
Kilograms per kilowatt-hour
Grams per cubic meter
Grams per kilogram
Symbol
kg/m3/sec
g/m3
kg/m3
mg/sec
g/m2 /day
Q
kg/nr/day
mg/m2/sec
kg/L
kg/sec
kg/m2/hr
kg/L/sec
kg/kWhr
g/m3
gAg
-------
APPENDIX C (continued)
U.S. Customary Unit
Metric Unit
en
o
n
o
£
"0
it
z
2
Q
O
1
i
*
§
Name
Pounds per square foot
Pounds per square inch
(force)
Pounds per 1,000 cubic feet
Pounds per 1,000 gallons
Pounds per year per acre
Pounds per year per cubic
foot
Pounds per year per square
foot
Square foot<
Square inch
Square mile
Square yard
Tons per acre
Tons per cubic yard
Watt-hour
Yard
Symbol
lb/ft2
psi
lb/1,000 ft3
lb/1,000 gal
1 b/yr/acre
1 b/yr/f t3
1 b/yr/ft2
ft2
in2
mi2
yd2
ton/acre
ton/yd3
Whr
yd
Mul ti pi i er
4.883
6,895
16.02
0.1198
1.121
16.02
4.882
9.29 x 10"2
6.452 x 10"2
2.59
0.836
0.2242
1.187
3.6
0.9144
Name
Kil ograms per square meter
Pascal
Grams per cubic meter
Grams per cubic meter
Kilograms per hectare per
year
Kilograms per cubic meter
per year
Kilograms per square meter
per year
Square meter
Square meter
Square kilometer
Square meter
Kil ograms per square meter
Megagrams per cubic meter
Joule
Meter
Syjbo|t
y
kg/nr
Pa
g/m3
g/m3
kg/ha/yr
kg/m3/yr
kg/m2/yr
m2
m2
km2
m2
kg/m2
Mg/m3
J
m
-------
Agency
Cincinnati OH 45268
Official Business
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Please make all necessary changes on the above label,
detach or copy, and return to the address in the upper
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If you do not wish to receive these reports CHECK HERE o;
detach, or copy this cover, and return to the address in the
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EPA/625/6-85/010
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