Biosolids Treatment Processes

830 Pages·2007·10.87 MB·English

by  Nazih K. Shammas PhD

Biosolids Treatment Processes
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V 6
OLUME
H E E
ANDBOOK OF NVIRONMENTAL NGINEERING
Biosolids Treatment
Processes
Edited by
Lawrence K. Wang, , ,
PhD PE DEE
Zorex Corporation, Newtonville, NY
Lenox Institute of Water Technology, Lenox, MA
Krofta Engineering Corporation, Lenox, MA
Nazih K. Shammas,
PhD
Lenox Institute of Water Technology, Lenox, MA
Krofta Engineering Corporation, Lenox, MA
Yung-Tse Hung, , ,
PhD PE DEE
Department of Civil and Environmental Engineering
Cleveland State University, Cleveland, OH
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eISBN 978-1-59259-996-7
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Library of Congress Cataloging-in-Publication Data
Biosolids treatment processes / edited by Lawrence K. Wang ... [et al.].
p. cm. — (Handbook of environmental engineering ; v. 6)
Includes bibliographical references and index.
ISBN 978-1-58829-396-1 (alk. paper)
1. Sewage sludge—Management. 2. Sewage—Purification. I. Wang, Lawrence K. II. Series.
TD767.B5535 2006
628.3—dc22 2006004783
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Preface
The past thirty years have seen the emergence of a growing desire worldwide
that positive actions be taken to restore and protect the environment from the
degrading effects of all forms of pollution—air, water, soil, and noise. Because
pollution is a direct or indirect consequence of waste, the seemingly idealistic
demand for ”zero discharge” can be construed as an unrealistic demand for zero
waste. However, as long as waste continues to exist, we can only attempt to abate
the subsequent pollution by converting it to a less noxious form. Three major
questions usually arise when a particular type of pollution has been identified:
(1) How serious is the pollution? (2) Is the technology to abate it available? and
(3) Do the costs of abatement justify the degree of abatement achieved? This book
is one of the volumes of the Handbook of Environmental Engineering series. The
principal intention of this series is to help readers formulate answers to the above
three questions.
The traditional approach of applying tried-and-true solutions to specific
pollution problems has been a major contributing factor to the success of envi-
ronmental engineering, and has accounted in large measure for the establish-
ment of a “methodology of pollution control.” However, the realization of the
ever-increasing complexity and interrelated nature of current environmental
problems renders it imperative that intelligent planning of pollution abatement
systems be undertaken. Prerequisite to such planning is an understanding of
the performance, potential, and limitations of the various methods of pollution
abatement available for environmental scientists and engineers. In this series
of handbooks, we will review at a tutorial level a broad spectrum of engineer-
ing systems (processes, operations, and methods) currently being utilized, or
of potential utility, for pollution abatement. We believe that the unified inter-
disciplinary approach presented in these handbooks is a logical step in the evo-
lution of environmental engineering.
Treatment of the various engineering systems presented will show how an
engineering formulation of the subject flows naturally from the fundamental
principles and theories of chemistry, microbiology, physics, and mathematics.
This emphasis on fundamental science recognizes that engineering practice has
in recent years become more firmly based on scientific principles rather than
on its earlier dependency on empirical accumulation of facts. It is not intended,
though, to neglect empiricism where such data lead quickly to the most eco-
nomic design; certain engineering systems are not readily amenable to funda-
mental scientific analysis, and in these instances we have resorted to less science
in favor of more art and empiricism.
Because an environmental engineer must understand science within the con-
text of application, we first present the development of the scientific basis of a
particular subject, followed by exposition of the pertinent design concepts and
operations, and detailed explanations of their applications to environmental qual-
v
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vi Preface
ity control or remediation. Throughout the series, methods of practical design and
calculation are illustrated by numerical examples. These examples clearly demon-
strate how organized, analytical reasoning leads to the most direct and clear solu-
tions. Wherever possible, pertinent cost data have been provided.
Our treatment of pollution-abatement engineering is offered in the belief that
the trained engineer should more firmly understand fundamental principles, be
more aware of the similarities and/or differences among many of the engineer-
ing systems, and exhibit greater flexibility and originality in the definition and
innovative solution of environmental pollution problems. In short, the environ-
mental engineer should by conviction and practice be more readily adaptable to
change and progress.
Coverage of the unusually broad field of environmental engineering has de-
manded an expertise that could only be provided through multiple authorships.
Each author (or group of authors) was permitted to employ, within reasonable
limits, the customary personal style in organizing and presenting a particular sub-
ject area; consequently, it has been difficult to treat all subject material in a homo-
geneous manner. Moreover, owing to limitations of space, some of the authors’
favored topics could not be treated in great detail, and many less important topics
had to be merely mentioned or commented on briefly. All authors have provided
an excellent list of references at the end of each chapter for the benefit of the inter-
ested readers. As each chapter is meant to be self-contained, some mild repetition
among the various texts was unavoidable. In each case, all omissions or repetitions
are the responsibility of the editors and not the individual authors. With the cur-
rent trend toward metrication, the question of using a consistent system of units
has been a problem. Wherever possible, the authors have used the British system
(fps) along with the metric equivalent (mks, cgs, or SIU) or vice versa. Conversion
Factors for Environmental Engineers are attached as an appendix in this hand-
book for the convenience of international readers. The editors sincerely hope that
this duplicity of units’ usage will prove to be useful rather than being disruptive to
the readers.
The goals of the Handbook of Environmental Engineering series are: (1) to
cover entire environmental fields, including air and noise pollution control,
solid waste processing and resource recovery, physicochemical treatment pro-
cesses, biological treatment processes, biosolids management, water resources,
natural control processes, radioactive waste disposal, and thermal pollution
control; and (2) to employ a multimedia approach to environmental pollution
control since air, water, soil, and energy are all interrelated.
As can be seen from the above handbook coverage, no consideration is given
to pollution by type of industry or to the abatement of specific pollutants.
Rather, the organization of the handbook series has been based on the three
basic forms in which pollutants and waste are manifested: gas, solid, and liq-
uid. In addition, noise pollution control is included in the handbook series.
This particular book, Volume 6, Biosolids Treatment Processes, is a sister book
to Volume 7, Biosolids Engineering and Management. Both biosolids books have
been designed to serve as basic biosolids treatment textbooks as well as com-
prehensive reference books. We hope and expect they will prove of equal high
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Preface vii
value to advanced undergraduate and graduate students, to designers of wastewa-
ter, biosolids, and sludge treatment systems, and to scientists and researchers. The
editors welcome comments from readers in all of these categories. It is our hope that
both books will not only provide information on the physical, chemical and biologi-
cal treatment technologies, but will also serve as a basis for advanced study or spe-
cialized investigation of the theory and practice of individual biosolids management
systems.
This book, Volume 6, Biosolids Treatment Processes, covers the topics of bio-
solids characteristics and quantity, gravity thickening, flotation thickening,
centrifugation, anaerobic digestion, aerobic digestion, lime stabilization, low
temperature thermal processes, high temperature thermal processes, chemical
conditioning, stabilization, elutriation, polymer conditioning, drying, belt filter,
composting, vertical shaft digestion, flotation, biofiltration, pressurized ozona-
tion, evaporation, pressure filtration, vacuum filtration, anaerobic lagoons, ver-
micomposting, irradiation, and land application.
The sister book, Volume 7, Biosolids Engineering and Management, covers additional
topics on sludge and biosolids transport, pumping and storage, sludge conversion
to biosolids, waste chlorination for stabilization regulatory requirements, cost esti-
mation, beneficial utilization, agricultural land application, biosolids landfill engi-
neering, ocean disposal technology assessment, combustion and incineration, and
process selection for biosolids management systems.
The editors are pleased to acknowledge the encouragement and support
received from their colleagues and the publisher during the conceptual stages
of this endeavor. We wish to thank the contributing authors for their time and
effort, and for having patiently borne our reviews and numerous queries and
comments. We are very grateful to our respective families for their patience
and understanding during some rather trying times.
Lawrence K. Wang, Lenox, MA
Nazih K. Shammas, Lenox, MA
Yung-Tse Hung, Cleveland, OH
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Contents
Preface...........................................................................................................................v
Contributors...........................................................................................................xxiii
1 Characteristics and Quantity of Biosolids
Nazih K. Shammas and Lawrence K. Wang.....................................................1
1, Introduction...................................................................................................................................................1
2. Primary Biosolids.........................................................................................................................................3
2.1. Estimation of Primary Biosolids Production.....................................................................................3
2.2. Factors Affecting Solids Removal.....................................................................................................7
2.3. Composition and Characteristics of Primary Biosolids....................................................................9
3. Biological Biosolids...................................................................................................................................10
3.1. General Characteristics.....................................................................................................................10
3.2. Activated Sludge...............................................................................................................................10
3.3. Trickling Filter Biosolids.................................................................................................................22
3.4. Biosolids from Rotating Biological Contactors..............................................................................26
3.5. Coupled Attached-Suspended Growth Biosolids............................................................................26
3.6. Denitrification Biosolids..................................................................................................................27
4. Chemical Biosolids.....................................................................................................................................27
5. Characteristics of Biosolids.......................................................................................................................28
5.1. Specific Gravity and Volatility........................................................................................................28
5.2. Preconcentration or Dewatering of Biosolids.................................................................................29
5.3. Particle Surface Charge and Hydration...........................................................................................31
5.4. Particle Size.......................................................................................................................................32
5.5. Compressibility.................................................................................................................................33
5.6. Biosolids Temperature......................................................................................................................34
5.7. Ratio of Volatile Solids to Fixed Solids..........................................................................................34
5.8. Biosolids pH......................................................................................................................................34
5.9. Septicity.............................................................................................................................................34
5.10.Trace Elements and Heavy Metals...................................................................................................34
6. Examples.....................................................................................................................................................35
6.1. Example 1: Determination of Biosolids Volume............................................................................35
6.2. Example 2: Determination of Solids Content After Digestion.......................................................36
6.3. Example 3: Determination of Biosolids Production.......................................................................36
6.4. Example 4: Interaction of Yield Calculations and the Quantitative Flow Diagram.....................40
Nomenclature....................................................................................................................................................40
References.........................................................................................................................................................41
2 Gravity Thickening
Nazih K. Shammas and Lawrence K. Wang...................................................45
1. Introduction.................................................................................................................................................45
1.1. General..............................................................................................................................................45
1.2. Gravity-Thickening...........................................................................................................................46
1.3. Process Evaluation............................................................................................................................46
1.4. Types and Occurrence of Thickening Processes.............................................................................47
2. Sedimentation Basins.................................................................................................................................47
2.1. Primary Sedimentation.....................................................................................................................47
2.2. Secondary Sedimentation.................................................................................................................47
3. Gravity Thickeners.....................................................................................................................................47
3.1. Introduction.......................................................................................................................................47
3.2. Theory................................................................................................................................................48
3.3 System Design Considerations.........................................................................................................49
ix
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x Contents
4. Cost.............................................................................................................................................................55
4.1. Capital Cost.......................................................................................................................................55
4.2. Operating and Maintenance Cost.....................................................................................................55
5. Design of Thickeners.................................................................................................................................56
5.1. Input Data..........................................................................................................................................57
5.2. Design Parameters............................................................................................................................58
5.3. Design Procedure..............................................................................................................................59
5.4. Output Data.......................................................................................................................................61
6. Design Example 1.......................................................................................................................................61
6.1. Thickener Surface Area....................................................................................................................61
6.2. Hydraulic Loading............................................................................................................................62
6.3. Torque Requirements........................................................................................................................62
6.4. Tank Depth........................................................................................................................................62
7. Design Example 2.......................................................................................................................................63
7.1. Quantity of Sludge and Solids..........................................................................................................63
7.2. Surface Area of Thickeners..............................................................................................................63
7.3. Diameter of Thickeners....................................................................................................................64
8. Design Example 3.......................................................................................................................................64
8.1. Height of Sludge at the Required Solids Concentration (C).........................................................64
u
8.2. Surface Area of Thickener................................................................................................................64
8.3. Solid Loading....................................................................................................................................65
Nomenclature....................................................................................................................................................66
References.........................................................................................................................................................66
Appendix...........................................................................................................................................................69
3 Flotation Thickening
Lawrence K. Wang, Nazih K. Shammas, William A. Selke,
and Donald B. Aulenbach...........................................................................71
1. Introduction.................................................................................................................................................71
1.1. Flotation Processes...........................................................................................................................71
1.2. DAF Thickener Components............................................................................................................72
1.3. DAF Thickener Advantages and Disadvantages.............................................................................72
2. DAF Thickener Process Description.........................................................................................................73
2.1. Full presentation DAF-Thickening System.....................................................................................74
2.2. Partial Pressurization DAF-Thickening System.............................................................................74
2.3. Recycle Pressurization DAF-Thickening System...........................................................................74
3. Process Applications and Limitations.......................................................................................................75
3.1. Sludge Thickening Applications......................................................................................................76
3.2. DAF Thickening Process Limitations..............................................................................................76
4. Process Design Considerations..................................................................................................................76
4.1. Rectangular or Circular Shape.........................................................................................................76
4.2. Concrete or Steel Construction........................................................................................................76
4.3. Pilot-Scale or Bench-Scale Experiments.........................................................................................78
4.4. Influent Feed Characteristics............................................................................................................78
4.5. Thickener Surface Area....................................................................................................................79
4.6. Air-to-Solids Ratio............................................................................................................................81
4.7. Polymer Usage..................................................................................................................................83
4.8. Pressurization System.......................................................................................................................83
4.9. Operating Pressure............................................................................................................................83
4.10.Quantity of Pressurized Flow...........................................................................................................84
4.11.Number of Units................................................................................................................................84
4.12.Feed Sludge Line..............................................................................................................................84
4.13.Thickened Sludge Removal..............................................................................................................84
4.14.Bottom Sludge Draw Off, Subnatant Line, Pressurized Flow Piping, and Controls....................84
5. Process Performance..................................................................................................................................85
5.1. Performance Data..............................................................................................................................85
5.2. Factors Affecting Performance........................................................................................................85
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Contents xi
6. Process Cost and Operation Considerations.............................................................................................86
6.1. Capital Cost.......................................................................................................................................86
6.2. Operating and Maintenance Costs...................................................................................................87
7. Process Reliability and Environmental Impact.........................................................................................87
7.1. Reliability..........................................................................................................................................87
7.2. Environmental Impact......................................................................................................................87
8. Process Design Criteria and Procedures...................................................................................................88
8.1. Design Criteria..................................................................................................................................88
8.2. Input Data of DAF Thickener Design..............................................................................................88
8.3. Design Parameters............................................................................................................................89
8.4. Design Procedure for DAF Thickener With No Recycle (Direct Pressurization).........................89
8.5. Design Procedures for DAF Thickener With Recycle....................................................................90
8.6. Output Data of DAF Thickener Design...........................................................................................91
9. Design and Application Examples............................................................................................................91
9.1. Example 1. Design of a DAF Thickener With No Recycle............................................................91
9.2. Example 2. Design of a DAF Thickener With Recycle..................................................................93
9.3. Example 3. Complete DAF Thickening System Design.................................................................95
Nomenclature....................................................................................................................................................97
References.........................................................................................................................................................97
Appendix.........................................................................................................................................................100
4 Centrifugation Clarification and Thickening
Lawrence K. Wang, Shoou-Yuh Chang, Yung-Tse Hung,
H. S. Muralidhara, and Satya P. Chauhan..............................................101
1. Introduction...............................................................................................................................................101
2. Principles..................................................................................................................................................102
3. Types of Water Associated with Solid Particles.....................................................................................102
4. Types of Centrifuges................................................................................................................................103
4.1. Basket Centrifuge............................................................................................................................103
4.2. Solid-Bowl Centrifuge....................................................................................................................104
4.3. Disc Centrifuge...............................................................................................................................107
5. Performance of Centrifuges in Sludge Dewatering................................................................................109
5.1. Separation of Municipal Wastewater Treatment Plant Sludges by Centrifugation.....................109
5.2. Separation of Pulp and Paper Sludges by Centrifugation.............................................................110
5.3. Separation of Electroplating by Centrifugation............................................................................112
5.4. Separation of Coals and Refuse by Centrifugation.......................................................................114
5.5. Separation of Metallurgical Refinery Sludge by Centrifugation.................................................121
5.6. Separation of Cannery Waste Biological Sludge by Centrifugation............................................122
5.7. Separation of Potato Wastes by Centrifugation............................................................................122
6. Centrifugation Design Considerations....................................................................................................122
6.1. General Guidelines for Selecting a Centrifuge for Sludge Dewatering.......................................122
6.2. Centrifuge Manufacturers...............................................................................................................123
6.3. Materials for Centrifuge Construction...........................................................................................124
6.4. Advantages and Disadvantages of Centrifugation in Various Applications ...............................124
6.5. Design Criteria, Input Data, and Design Parameters....................................................................125
6.6. Design Procedure............................................................................................................................125
7. Operation and Maintenance.....................................................................................................................126
7.1. Troubleshooting..............................................................................................................................126
7.2. Preventive Maintenance.................................................................................................................126
7.3. Noise and Odor Control..................................................................................................................128
8. Design and Practical Application Examples...........................................................................................128
8.1. Example 1: Centrifugation System Design...................................................................................128
8.2. Example 2: Centrifugation System Chemical Requirements.......................................................129
8.3. Example 3: Centrifugation System Cost Estimation.....................................................................129
8.4. Example 4: Centrifugation Case Study..........................................................................................129
Nomenclature..................................................................................................................................................131
References.......................................................................................................................................................132
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xii Contents
5 Anaerobic Digestion
Jerry R. Taricska, David A. Long, J. Paul Chen, Yung-Tse Hung,
and Shuai-Wen Zou...................................................................................135
1. Introduction...............................................................................................................................................135
2. Theory.......................................................................................................................................................136
2.1. Nature of organic Wastes...............................................................................................................136
2.2. Biochemistry and Microbiology of the Anaerobic Process..........................................................137
2.3. Reactor Configurations...................................................................................................................138
2.4. Organic Loading Parameters..........................................................................................................140
2.5. Time and Temperature Relationships............................................................................................141
2.6. Nutrient Requirements....................................................................................................................142
2.7. Gas Production and Utilization......................................................................................................142
3. Design Practice.........................................................................................................................................144
3.1. Anaerobic Treatability Studies.......................................................................................................144
3.2. Anaerobic Reactor Design and Sizing...........................................................................................146
3.3. Tank Construction and System Components.................................................................................149
3.4. System Equipment and Appurtenances.........................................................................................150
3.5. Gas Utilization................................................................................................................................159
3.6. Sludge Pumping and Piping Considerations.................................................................................160
4. Management of Digestion........................................................................................................................160
4.1. Control of Sludge Feed...................................................................................................................160
4.2. Withdrawal of Sludge and Supernatant.........................................................................................161
4.3. Maintenance of Reactor Stability...................................................................................................161
4.4. Digester Performance Criteria........................................................................................................162
5. Capital and Operating Costs....................................................................................................................162
5.1. Generals...........................................................................................................................................162
5.2. Items Included in Cost Estimates...................................................................................................162
6. Design Examples......................................................................................................................................163
6.1. Example Using Standards Design..................................................................................................163
6.2. Example Using Solids Loading Factor..........................................................................................165
6.3. Example Using Modified Anaerobic Contact Process..................................................................167
7. Recent Development in Anaerobic Process............................................................................................168
Nomenclature..................................................................................................................................................173
References.......................................................................................................................................................173
6 Aerobic Digestion
Nazih K. Shammas and Lawrence K. Wang.................................................177
1. Introduction...............................................................................................................................................177
2. Process Description..................................................................................................................................178
2.1. Microbiology...................................................................................................................................178
2.2. Advantages......................................................................................................................................178
2.3. Disadvantages.................................................................................................................................178
3. Process Variations....................................................................................................................................179
3.1. Conventional Semibatch Operation...............................................................................................179
3.2. Conventional Continuous Operation..............................................................................................179
3.3. Autothermal Thermophilic Aerobic Digestion (Using Air).........................................................179
3.4. Autothermal Thermophilic Aerobic Digestion (Using Oxygen)..................................................181
4. Design Considerations.............................................................................................................................181
4.1. Temperature....................................................................................................................................181
4.2. Solids Reduction.............................................................................................................................182
4.3. Oxygen Requirements.....................................................................................................................183
4.4. Mixing.............................................................................................................................................184
4.5. pH Reduction ..................................................................................................................................184
4.6. Dewatering......................................................................................................................................184
5. Process Performance................................................................................................................................185
5.1. Total Volatile Solids Reduction.....................................................................................................185
5.2. Supernatant Quality........................................................................................................................185
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