Environmental Engineering BY PEAVY,ROWE

214 Pages·2013·114.23 MB·English

McGraw-Hill Series in Water Resources
ENVIRONMENTAL
and Environmental Engineering
ENGINEERING
Rolf Eliassen, Paul H. King, and Ray K. Linsley
Consulting Editors
Bailey and Ollis: Biochemical Engineering Fundamentals
Bishop: Marine Pollution and Its Control
Biswas: Modelsfor Water Quality Managemeni
Bockrath: Environmental Law for Engineers. Scientisls, and Managers
Bouwer: Gro!{ndwater Hydrology
Canter: Environmental Impact Assessment Howard S. Peavy
Chanlett: Environmental Protection
Professor of Civil Engineering
Gaudy and Gaudy: Microbiologyfor Environmental Scientists and Engineers
Montana Scate University
Haimes: Hierarchical Analysis of Water Resources Systems: Modelling and
Optimization of Large-Scale Systems Donald R. Rowe
Hall and Dracup: Water Resources Systems Engineering
Linsley and Franzini: Water Resources Engineering Professor of Civil Engineering
Linsley, Kohler, and Paulhus: Hydrology for Engineers King Saud UniverSity
Metcalf & Eddy, Inc.: Wastewater Engineering.' Collection and Pumping of Wastewater Saudi Arabia
Metcalf & Eddy, Inc.: Wastewater Engineering. Trealment, Disposal. Reuse
George Tchobanoglous
Peavy, Rowe, and Tchobanoglous: Environmental Engineering
Rich: Low-Maintenance, Mechanically-Simple Wastewater Treatment Systems Professor of Civil Engineering
Sawyer and McCarty: Chemistry for Environmental Engineering University of California, Davis
Steel and McGhee: Water Supply and Sewerage
Tchobanoglous, Theisen, and Eliassen: Solid Wastes, Engineering Principles and
Management Issues
McGraw-Hill Book Company
New York St. Louis San Francisco Auckland Bogota Hamburg
London Madrid Mexico Montreal New Dehli
Panama Paris Siio Paulo Singapore Sydney Tokyo Toronto
CONTENTS
ENVIRONMENTAL ENGI~EERING
INTERNATIONAL EDITION 1985
Exclusive rights by McGraw-Hili Book Co., Singapore
for manufacture and export. This book cannot be re-exported
from the country to which it is consigned by McGraw-HilI.
40 39 38 37 36 35 34 33 32 31
15 14 13 12 11
CTP BJE
Preface
XI/I
Copyright © 1985 by McGraw-Hili, Inc.
IntrncluClion
All rights reserved. No part of this publication may be
reproduced or distributed in any form or by any means,
I-I ·The Em'ironlllcnt
or stored in a data base or a retrieval system, without
1-2 The Im[lact 01' Ilulllam upon the Environment 2
the prior written permission of the publisher.
1-3 The Im[lact or the En\ironment upon Humans 4
1-4 Impro\'cment of Environmental Quality 6
This book was set in Times Roman.
1-5 The Rolc of the Environmental Engineer 7
The editors were Kiran Verma and David A. Damstra.
The production supervisor was Leroy A. Young. ReI-ercnces ~
Part 1 Water
...L ibra./},.()f.c;:()1"!9.ress .Ca~loging in Publication Data Charaderistics;
2 Water Quality: Definitions,
Peavy, Howard S. and Perspect ives II
Environmental engineering.
2-1 The Hydraulic Cycle and Water Quality 12
(MCGraw-Hili series in water resources and environ PHYSICAL WATER-QUALITY PARAMETERS 14
mental engineering) 2-2 Suspended S,1Iid, 15
Includes bibliographical references and indexes. 2-3 Turbidity 17
1. Environmental engineering. I. Rowe, Donald R.
2-4 Color 18
II. Tchobanoglous, George. III. Title. IV. Series.
2-5 Taste and Odol 20
TD145.P43 1985 628 84-3854
2-6 Temperature 22
ISBN 0-07-049134-8
CHEMICAL \\ATER-QUALITY PARAMETERS 23
When ordering this title use ISBN 0-07 -1 00231-6 2-7 Chemistn of S"lutions' 23
2-8 Total Dissohcd Solid, 28
2-9 Alkalinit\ 31
2·10 Hardness
:2-11 Fluoride 3(,
2·12 Metals 37
2-1] OrganH.:" 38
2-14 Nutllcnh -14
Printed in Singapore
CONTENTS vii
vi CONTENTS
46 · 4-8 Filtration 165
BIOLOGICAL WATER-QU-\UTY PARAMETERS
' 4-9 Disinfection 182
47 ,. t·
22--1156 PPaatthhooggeenn sI ndicators 50 OTHER WATER-TREATMENT PROCESSES 190
WATER QUALITY REQUIREMENTS 54 ~ 4-10 Dissolved Solids Removal 190
DiSCUSSIOn Topics and Problems ~ .
2-17 In-Stream Standards 54 References '104 .
2-18 Potable Water Standards 55
2-19 Wastewater Effluent Standards 56 5 Engineered Systems for Wastewater Treatment
Discussion Topics and Problems 57 and Disposal 207
References . 62
208
5-1 Wastewater Characteristics
3 Water Purification Processes in Natural Systems 63
5-2 Effluent Standards 211
PHYSICAL PROCESSES 64 5-3 Terminology in Wastewater Treatment 212
3-1 Dilution 64 PRIMARY TREATMENT 2Pl
3-2 Sedimentation and Resuspension 65 5-4 Screening 217
3-3 Filtration 66 5-5 Comminuting 220
3-4 Gas Transfer 66 5-6 Grit Removal 221
3-5 Heat Transfer 71 5-7 Flow Measurement 224
CHEMICAL PROCESSES 73 5-8 Primary Sedimentation 224
229
3-6 Chemical Conversions 73 SECONDARY TREATMENT
BIOCHEMICAL PROCESSES 74 5-9 Growth and Food Utilization 230
234
3-7 Metabolic Processes 75 5-10 Suspended-Culture Systems 234
3-8 Microorganisms in Natural Water Systems 79 5·11 Activated Sludge 248
5-12 Ponds and Lagoons
RESPONSE OF STREM.. . lS TO BIODEGRADABLE. 5·13 Attached-Culture Systems 255
ORGANIC WASTE 83 5-14 Secondary Clarification 268
3-9 Dissolved-Oxygen Balance .... .. ..... ?;l. _ ................. . . ~cl.~. P.i~iflf~c.t.iml.of Effiw:ots ...................................................... . 277
3-10 Dissolved-Oxygen Model g5 SLUDGE TREATMENT AND DISPOSAL 278
3-.11 Organic Discharge and Stream Ecology 94 5-16 Sludge Characteristics 279
281
APPLICATION OF NATURAL .pROCESSES IN 5-17 Sludge Thickening
285
ENGINEERED SYSTEMS 5-18 Sludge Digestion
292
3-12 Physical Processes 5-19 Sludge Disposal
3-i3 Chemical Processes ADVANCED WASTEWATER TREATMENT 294
3-14 Biological Processes 5-20 Nutrient Removal 295:'
Discussion Topics and Problems 5-21 Solids Removal 301
Refere.nces 302
WASTEWATER DISPOSAL AND REUSE
4 Engineered Systems for Water Purification 104 5-22 Wastewater Disposal 303
306
4-1· Historical Overview of Water Treatment 105 5-23 Wastewater Reuse .314
4-2 Water-Treatment Processes 107 Discussion Topics and Problems 322
References
WA TER-TRFA1 M ENT PROCESSES.
THEORY AND .APPLICATION 109 6 Environmental Engineering Hydraulics Design 324
4-3 Aeraiillil 110 WATER DISTRIBUTION SYSTEMS 324
4-4 Solids Separation \j)\ - \IJ) 113 324
In 6-1 Methods of Distributing Water
4-5 Settling Operatiolls 326
4-(, Cllagulatioll ~ S'\- \G1 ~11.5111 66--23 DDiissttrriibbuutt iioonn SRyessteermvos irs 331
4-7 Softening
CONTENTS ix
v iii CONTENTS
455
333 7-9 Oxides of Nitrogen
6-4 Distribution System Components 335 7-10 Photochemical Oxidants 461
6-5 Capacity and Pressure Requirements 337 7-11 Indoor Air Pollution 463
<6-6 Design of Distribution Systems 464
338 AIR-QUALITY MANAGEMENT CONCEPTS
Hydraulic Analysis of Distribution Systems
6~7 346 477
6-8 Cross-Connections in Distribution Systems Discussion Topics and Problems
347 480
6-9 Construction of Water Distribution Systems References
348
6-10 Pumping Required for Water Supply Systems
348
WASTEWATER COLLECTION 8 Meteorology and Natural Purification Processes 483
349
6-11 Types of Collection Systems 349 ELEMENTAL PROPERTIES Of THE ATMOSPHERE 483
-: < 6666----11112345 TCBDyoaepslslieiecgsc n Cto iooof nfnS s SeSiwadyneesirrttaesa tmrioy A nSspe pwinue rtrhtse en Danecseigsn of Sewers 333655340 g8i)-o-:1} SHPcreaeasltes su roef i\lotilln 444499881364
666---111687 PCMroaenipnsattrreauntcaitoninoc neo ofo ffC SSoeenwwtaeecrrsts Drawings and Specifications 333677911 888---456 WMRclOnlacislt tiuvree Humidity 449955
371
6-19 Design of Stormwater Sewers INFLUENCE OF i\ILTEOROLOGICAL PHENOMENA ON
WATER AND WASTEWATER PUMPING 372 AIR QUALITY 495
372 496
6-20 Pumps 375 8-7 Lapse Rates and DI'>persion 498
6-21 Pump Drive Units 378 8-8 Pressure Systems and Dispersion 498
6-22 Pump Application Terminology and Usage 384 8-9 Winds and Dispersion 499·
6-23 Pump Operating Characteristics and Curves 3')0 8-10 MOiSture and Dispersion 499
6-24 Analysis of Pump Systems 8-11 Modeling
397
6-25 Pump Stations for Water and Wastewater EFFECTS or AIR POLLUTION ON METEOROLOGICAL
- HYDRAULIC ANALYSIS OF WATER AND CONDITIONS 507
397 508
WASTEWATER TREATMENT 8-12 Changes on the Mesoscale and Microscale
397 509
6-26 Treatment Plant Design ,--399, __ . __~ : 13_ _ ~~b'Hlge.s _0.11_ the_ MaC.fQseale 510
~ 6-27 Preparation of Hydraulic FFOfiks< <" << " < <. "" <" 0<" <- -", ---.. -.. ------.. - 406 Discussion Topics and Problems 512
Discussion Topics and Problems References
412
References
9 Engineered Systems for Air Pollution Control 514
Part 2 . Air 514
9-1 Atmospheric Cleansing Processes
516
9-2 Approaches to Contaminant Control
-""""' '7 Air Quality: Definitions, Characteristics, and CONTROL DEVICES rOR PARTICULATE CONTAMINANTS 518
Perspectives 417 520
9-3 Gravitational Sel1!ing Chambers
~ AIR POLLUTION-PAST, PRESENT, AND FUTURE 418 9-4 Centrifugal Collect(),~S 523
528
418 9-5 Wct Colkctnr,
7-1 Historical Overvie\>.' 533
420 '-)-(, Fahric Filter, (BaglHlllse Filters)
'""""' 7-2 Global Implications of Air Pollution 424 9-7 Electrostatic PrccipiLlt()fS (ESP)' 536
7-3 Units of Measurement
7-4 Sources of poJlutan ts 426 CONTIWL DEVICES FOR GASEOUS CONTAMINANTS 540
~. CLASSIFICATION OF POLLUTANTS 429 ')-8 Adsorpti(lll 554405
431 9-9 ,\ OSorptll)Jl
7-5 Particulates 557
442 ,-)·10 Conlicns"tloll
7-6 Hydrocarbons 559
445 9-11 ('omou'>1lt)n
7-7 Carbon Monoxide 56J
449 l)_I~ ,\utt.lllIl1tl\r t:!llh~H)!l ('~)fltrol
7-8 Oxides of Sulfur
-----..,
r
CONTENTS xi ~
x CONTENTS ,
11-10 Determination of Vehicle and Labor Requirements 607 ~'
Discussion Topics and Problems 565 615
References 567 II-II Collection Routes 618 r~
TRANSFER AND TRANSPORT
620 ...
11-12 Transfer Stations
622
11-13 Location of Transfer Stations
Part 3 Solid Waste 11-14 Transfer Means and Methods 622
626 rt
PROCESSING TECHNIQUES
10 Solid Waste: Definitions, Characteristics, and II-IS Mechanical Volume Reduction 627 r
Perspectives 573 627
11-16 Thermal Volume Reduction
627
TYPES OF SOLID WASTES 573 11.-17 Manual Component Separation
628
10-1 Municipal Wastes 574 ULTIMATE DISPOSAL ~
10-2 Industrial Wastes 574 11-18 Landfilling with Solid Wastes 628
10-3 Hazardous Wastes 575 11-19 Design and Operation of Landfills 638
646
SOURCES OF SOLID WASTES 575 11-20 Landfarming 647
11-21 Deep-Well Injection
10-4 Sources of Municipal Wastes 575 648
Discussion Topics and Problems
10-5 Sources of Hazardous Wastes 576 652
References
PROPERTIES OF SOLID WASTES 576
10-6 Physical Composition 576
10-7 Chemical Composition 582
10-8 Changes in Composition 588 .12 Engineered Systems for Resource and
SOLID-WASTE MANAGEMENT AN OVERVIEW 588 Energy Recovery 653
10-9 Materials Flow in Society 588 653
PROCESSING TECHNIQUES
10-10 Reduction in Raw Materials Usage 589
65.4
10-11 Reduction in Solid-Waste Quantit ies 590 12-i Mechanical Size Alteration
656
10-12 Reuse of Solid-Waste Materials 590 12-2 Mechanical Component Separation 656-·-..
10-13 .. I'vlil.tel:iil.l.s. .R .e~o.Y\TY .... 591 12-3 Magnetic and Electromechanical Separation 657
10-14 Energy Recovery 592 12-4 Drying and Dewatering
10-15 Day-to-Day Solid-Waste Management 592 MA TERIALS-RECOVER Y SYSTEMS 657
Discussion Topics and Problems 592 657
12-5 Materials Specifications
References 593 657
12-6 Processing and Recovery Sy"stems
659
)2-7 System Design a~d Layout
11 Engineered Systems for Solid-Waste Management 594 RECOVERY OF BIOLOGICAL CONVERSION P·RODUCTS 659
660
II-I Functional Elements 594 12-8 Composting (Aerobic Conversion)
.663
17.-9 Anaerobic Digestion
SOLID WASTE GENERATION 594
665
RECOVERY OF THERMAL CONVERSION PRODUCTS
11-2 Typical Generation Rates 595 665
11-3 Estimation of Solid-Waste Quantities 598 12-10 Combustion of Waste Materials 670
11-4 Factors That Affect Generation Ratcs 598 12-11 Incineration with Heat Recovery 671
12-12 Use of Refuse-Derived Fuels (RDF)
ON-SITE HANDLING. STORAGE. t\ND PROCESSING 598 671
12-13 Gasification
11-5 On-Site Handling 599 12-14 Pyrolysis 672
11-6 On-Site Storage 599 RECOVERY OF ENERGY FROM CONVERSION PRODUCTS 672
11-7 On-Site Processing of Solid Wastes 601 673
12-I 5 Energy-Recovery Systems
COLLECTION OF SOLID \Vt\STES 601 674
12-16 Efficiency Factors
11-8 Collection Services 601 12-17 Deterrnination of t.nerg} Output and EtJicicncy 675
11-9 Types ofCollectioll Systcm, 1i05
xii CONTENTS
PREFACE
MATERIALS- AND ENERGY-RECOVERY SYSTEMS 675
Discussion Topics and Problems 677
References
677
Appendixes
A Quantities and Units 679
B Conversion Factors
683
C Properties of Water and Air
693
D· Water Quality Standards 696
Indexes
II
Name Index
---"'. Subject Index'
Engineers and scientists from a number of related disciplines have been involved
in the developmcnt of an academic basis for the understanding and management
of the environment. The'management of water quality has been dealt with in
microbiology and s<Jnitary engineering courses; air pollution problems have been
---.
covered in chemical and/or mechanical engineering courses; and the management
of solid waste, long neglected by academ icians. has been chiefly the purvey of those
directly rcsponsible for hlluling and disposlli operations.
During the last 10 to 13 years, schools of engineering have made considerable
progress toward bringing the principles drawn from many related academic
disciplines together and unifying them under the title environmental engineerilll).
Not surprisingly. texts .in .tbis relatively. new. subject. ar.ea. have dev<!loped along·
classical, separatist lines. Thus, there have been a number of texts featuring In
depth treatment of one specific area (ie .. water, air, solid waste) and few texts
attempting, to treat the subject 01' environmental engineering as a whole,
The purpose of Elll'ironmental Enyineerinq is to bring together and integrate
in a single text the morc gCntTti suhJect matter of the three principal areas of
---. .envirolJmental engincering--water. air. and solid-waste management. And, as
.Char. 1 indicates, this integration goes heyond binding three texts in a single cover.
Enl'irolltll('/I/(II Enqill('erilllj introduces a unique approach to the overall
concept of environmental engineering, an approach that emphasizes the relation
ship belll/een the princlrles observed in natural purification processes and those
employeed in enginecred processes. First. the physical, chemical, mathematical.
and biological principles of defining. quantifying, ane! measuring environmental
quality arc desCribed. Next. the processrs by which nature assimilates waste
~'.
material are discusscd and tlicnatul'al purification rrocesses that form the ba~cs
of engineered systems are detailed Finally, the engineering principles and practices
involved In the design and operatil)n of conventional environmental engineering
works arc C()\'ercd at len)!tll.
xiii
xiv PREFAn
The breadth and depth of the matenal in this book precludes complete ENVIRONMENTAL ENGINEERING
coverage in a one-semster or one-quarter course. However, the arrangement of
the material lends itself to several different course formats.
•
I. For introductory engineering courses at the sophomore or junior \i.:vel, Chaps.
1.2,3.7,8. and 10 provide an overview of the principles involved in environ
mental engineering systems. These chapters assume a basic knowledge of
chemistry. biology, physics, and mathematics. However, because many
engineering curricula contain few chemistry and even fewer biology or micro
biology courses. the chapters review these subjects in detail. The introductory
sections of Chaps. 4. S. 9, II, and 12 may be utilized to add relevance to the
theoretical discussions. A course following this format will satisfy ABET
requirements for engineering science.
2. If the hrst approach is used for an introductory course. the remaining chapters
(4.5,6.9, II, and 12) can be used as a follow-up course in environmental
engineering design. This course should be restricted to engineering students at
the junior or senior level who have completed basic fluid mechanics. Such a
course would meet ABET's engineering design criteria.
3. A more classical approach would be to use the first six chapters as a text for
a one-semester or one-quarter course in water and wastewater engineering. A
second one-semester/quarter course on air-pollution control and solid-waste
management would use Chaps. 7 through 12. Designed for junior- or senior
level engineering students that have completed basic tluid mechanics, these
two' courses will meet ABET criteria for engineering design and science, or an
approximate one to one ratio.
4. Chapters 1,2.3,7.8, and 10 can also bc lIsed for a companion course in en
vironmental science for nonengineering students, provided allowance is made
.. for·the iimited mar-hema titalbackgroun'd 6fthc' itl ldenis:' .
Whatever the approach used, the text should leave students with a clear
understanding of the principles of all three of the major areas of enviromental
engineering. User comments and suggestions concerning the effectiveness of this
approach would be greatly appreciated.
The authors wish to acknowledge tile fact that development and publication '.:
of Environmental El7,1jineeriny would not have been possible without the help and
inspiration of our former professors, the challenge and mot ivation of our students,
the assistance and encouragement of our colleagues, the patience and forebearance
of our editors, and the SUpPGrt and understanding of our families.
HOI1'ord S. Peon:
Donald R. Rowe'
Ceorql' Tchohal/oglous
CHAPTER
ONE
INTRODUCTION
Environmental engineering has been defined as the branch of engineering that is
concerned with protecting the environment from the potentially deleterious
effects of human activity, protecting human populations from the effects of adverse
environmental factors, and improving environmental.quality for human health
and well-being. [1-2J
As the above definition implies, humans interact with their environment
sometimes adversely impacting the environment and sometimes being adversely
impacted by pollutants in the environment. An understanding of the nature of
the environment and of human interaction with it is a neces'ary prerequisite to
understanding the work of the environmental engineer.
1-] THE ENVIRONMENT
Simply stated, the environment can be defined as one's surroundings. In terms of
the environmental engineer's involvement, however, a more specific definition is
needed. To the environmental engineer. the word environment may tak.e on global
ciimensions. may refer to a very localized area in which a specific problem must be
addressed, or may, in the case of contained environments, refer to a small volume
or liquid. gaseolls. or solid materials within a treatment plant reactor.
The global environment consists of the atmosphere, the hydTosphere, and
the lithosphere in which the life-sustaining resources of the earth are contained.
The atIJlOspi1l'rc.;t mixture of gases extending outward from t~e surface of the eart h.
cvolved from elemeots of the earth that were gasified during its formation and
metamorphosis. The hydrosphere consists of the oceans, the lakes and streams.
and the shallow groundwater bodies that interflow with the surface water. The
lithosphere is the soil mant Ie that wraps the core of the earth.
The hiosphcre. a thin shell that encapsulates the earth. is made lip or the
;Itmosphcre and iltlwsphere adjacent to the surface of the earth. together \\it h the
2 INTRODuCTION INTRODUCTION 3
from a campfire. Even when use of fire became common, the relatively small
hydrosphere. It is within the biosphere that the life forms of earth. including
amounts of smoke generated were easily and rapidly dispersed and assimilated
humans. live. Life-sustaining materials In gaseous, liquid, and solid forms are hy t he at m0sphere.
cycled through the biosphere, providing sustenance to all living organisms.
Early civilizations often drank from the same rivers in which they bathed and
Life-sustaining resources- air, food, and water- are withdrawn from the
deposited their wastes, yet the impact of sLich use was relatively slight. as natural
biosphere. It is also into the biosphere that waste products in gaseous, liquid.
cleansing mechanisms easily restored water quality. These early humans used
and solid forms are discharged. From the beginning of time, the biosphere has
caves and other natural shelters or else fashioned their homes from wood, dirt,
received and assimilated the wastes generated by plant and animal life. Natural
or animal skins. Often nomadic, early popUlations left behind few items that were
systems have been ever active, dispersing smoke from forest fires, diluting animal
not readily broken down and absorbed by the atmosphere, hydrosphere, or litho
wastes washed into streams and rivers, and converting debris of past generations
sphere. And those items that were not broken down with time were so few in
of plant and animal life into soil rich enough to support future populations.
number and so innocuous as to present no significant solid-waste problems.
For every natural act of pollution, for every undesirable alteration in the
Only as early peoples began to gather toget her in larger, more or less stable
physical. chemical, or biological characteristics of the environment, for everv
groupings did their impact upon their local environments begin to be significant.
incident that eroded the quality of the immediate, or local, environment, ther~
[n 61 A.D., cooking and heating fires caused air-pollution problems so severe that
were natural actions that restored that quality. Onlyin recent years has it become
the Roman philosopher Seneca complained of "the stink of the smoky chimneys."
apparent that the sustaining and assimilative capacity of the biosphere, though
By the late eighteenth century, the waters of the Rhine and the Thames had
tremendous, is not, after all, infinite. Though the system has operated for millions
become too polluted to support game fish. From the Middle. Ages the areas
of years, it has begun to show signs of stress, primarily because of the impact of
where food and human waste were dumped harbored rats, flies, and other pests.
humans upon the environment.
Satisfying Acquired Needs
1-2 THE IMPACT OF HUMANS UPON THE ENVIRONMENT
But these early evidences of pollution overload were merely the prelude to greater
overloads to come. With the dawn of the industrial revolution, humans were
[n a natural state, earth's life forms live in equilibrium with their environment.
bet ter able than ever to sat isfy their age-old needs of air. water, food, and shelter.
The numbers and activities of each species are governed by the resources available
Increasingly they turned their attention to other needs beyond those associated
to them. Species interaction is common, with the waste product of one species often
With survival. By the late nineteenth and early twentieth centtlrje~>.~.l!t9.mobiles ........... .
forming the food supply of another. Humans alone have the ability to gather
<lppliances, and processed foods and beverages had become so popular as to seem .
. r.es.oyrce.s.fr()l11.tJI.':Y9.n<;i'(heir.immediate surroundings and process those resources
necessities, and meeting these acquired needs had become a major thruslof modern
into different. more versatile forms. These abilities have made it possible for human
industrial society.
population to thrive and flourish beyond natural constraints. But the natural and
. Unlike the natural need; discussed earlier, acquired needs are usually met
manufactured wastes generated and released into the biosphere by these increased
by Items that must be processed 'or manuf<ict'ure'd or refined, and the production,
numbers of human beings have upset the natural equilibrium.
distribution, and use of such items usually results in more complex residuals,
Anthropogenic, or human-induced, pollutants have overloaded the system.
many of which are not compatible with or readily assimilated by the environment.
The overloading came relatively late in the course of human interaction with the
Take, for example, a familiar modern appliance--the toaster. The shell and
environment, perhaps because early societies were primarily concerned with
the heating elements are likely to be made of steel, the handle of the lift lever of
meeting natural needs, needs humans share in C0mll10n with most of the higher
plas·tic. Copper wires and synthetic insulation may be used in the connecting cord,
mammals. These peoples had not yet begun to be concerned with meeting the
and rubber may be used on the plug. In assessing the pollutants generated by the
acquired needs associated with more advanced Civilizations.
manufacture and sale of this simple appliance, it would be necessary to include all
the resources expended in the milling of the metals, the extracting and refining of
Satisfying Natural Needs the petroleum, the shipping of the various materials, then the' manufacturing,
shipping, and selling of the finished product. .The potential impact of all of these
Early hum,!ns used natural resoui-ces to satisfy their needs for air, water. food, anc!
activities upon air and water quality is significant. Furthermore, if the pollution
shelter. These natural. unprocessed resources were readilv available in the
poteillial involving the manufacture and use of the heavy equipment needed for
biosphere, and the resiclues generated by t he use of such resol;rces were generally
the extraction and processing of the raw materials used in the various toaster
compatible with, or readily assimilated by, the eIlI·lronment. Prllnitlve humans
components is considered, the list could go on ad nauseum. And the solid-waste
ate plant and animal foods without even di;tllrbing the atmosphere with the smoke
II"TRODl'CTION 5
4 INTRODUCTION
likely suffered from the ill effects of air pollution for centuries, but it is only in this
disposal problems that arise when it is time to get rid of the toaster become a
century that II1creasingly heavy pollution has caused health problems so dramatic
further factor. as to be easily attributed to air pollution. Several key incidents helped call attention
As a rule, meeting the acquired needs of modern societies generates more
to the potentially deadly effect of air pollution. Several killer smogs settled over
residuals thar: meeting natural needs, and these residuals are likelY to be less
London in the last quarter of the nineteenth century. but the true extent of the
compatible with the environment and less likely to be readily assimilated into the
air-pollution problem in that city did not become apparent until 4000 deaths and
biosphere. As societies ascend the socioeconomic ladder, the list of acquired
countless illnesses were attributed to the London smog of 1952.
needs, or luxuries, increases, as do the complexity of the production chain and the
Though the 20 deaths caused by a smog over Donora, Pennsylvania. in 1948
ma~s and complexity of the pollutants generated. Consequently, the impact of
.raised some alarm. It was not until the New York i~version of 1963 clcJlmed several
modern human populations· upon the environment is of major concern to the
hundred lives that this country began to take the fight against air pollution seriousl\".
environmental engineer: Monitoring of the sulfur dioxide, lead, and carbon monoxide levels in areas su~h
as the smog-shrouded Los Angeles basin has revealed that the high levels of these
and other contaminants pose direct and indirect threats to human health. These
1-3 THE IMPACT OF THE ENVIRONMENT UPON HUMANS findings have made air-pollution control a top priority of the Environmental
Protection Agency and a major concern of environmental engineers, who are
Though rivers become stagnant, skies smoke-shrouded, and dumping grounds now called upon to devise management programs designed to alter the pattern of
odoriferous and unsightly, populations generally manage to ignore their impact air pollution begun centuries ago and continued until the present time.
on the environment until they begin to become aware of the ill efrects that a polluted Other environmentally related health problems also concern the envIron
environment can have upon their own health and well-being. Though stagnant mental engineer. The widespread ·use of chemicals in agriculture and industry
rivers, smoggy skies. and unsightly dumps were aesthetically displeasing to the has introduced many new compounds into the environment. Some of these
citizens of overcrowded cities of earlier centuries, no attempt was made to re\·erse compounds have been diffused in small quantities throughout the environment.
the negative impact humans had on their environment unlil it becamc evident while others have been concentrated at disposal sites. Such chemicals may be
that heavily polluted water, air, and soil could exert an equally negative impact spread through air. watcr, and soil, as well as through the food chain. and thus
on the health, the aesthetic and cultural pleasures, and the economic opportunities pose a potential threat to all humans.
The pesticide DDT was used extensively during the mid-century decades and
of humans.
has been instrumenta I. i.n the. eli.rpioalion .0J malaria· in· many parts· of·rhe· i.\laird·.···· ...
In addition, this· pesticide was used extensively to control insect pests on food and
Health Concerns fiber plants. Its beneficial use to humans was widely acclaimed, and its promoter.
Paul Muller. was awarded a Nobel prize in 1958 fo·r his contribution to public
Elements of the air, the water. and the land may host ·harmful biological and
health. Subsequent research. however. has shown that DDT is a cumulative toxin
chemical agents that impact the health of humans. A wide range of communicable
. that has adversely ;tfrccted many nontarget species. Traces of DDT can be found in
diseases can be spread through elements of the environment by huma.n and
almost all living org;lnisms throughout the world- including humans. Although
animal waste products. This is most clearly evidenced. by the plagues of the M idclle
·the use of DDT is no\\' b:lnnecl in the United States and several other countries. the
Ages when disease spread through rats that fed ·on contaminated solid and human
chemical is stdl being manufactured. primarily for use in several developing
waste and disease carried by waterborne para5ites and bacteria ran rampant
countries. particularly in tropical zones where its benefits are still considered to
through the population of Europe.
outweigh Its liabilities.
It has only been in the last century that the correlation between waterborne
A more recent example of chemical toxins that threaten health is the chemical
biological agents and human diseases has been proved and effective preventive
dioxin The formatillil of this chemical. the scientific name of which is 2,3.7,R
measures have been taken. Through immunization and environmental control
tetrachloro-dibenzoparadioxin. is an unintentional by-product ofa manufacturlllg
programs, the major diseases transmitted via the environment ha\'e all but been
process used with some herhicides anc! wood-preserving compounds. It is also
eliminated in developed countries. No country, however, is totally immune from
formed in t he prod uct ion of some d isi nfectan ts ancl ind ustria I clean ing com pou nds.
outbreaks of environmentally transmitted disease. The transmission uf viruses
Dioxin is an extremely toxic substance. and its presence in excess of I ppb (part
and proiozoa has proved particularly difficult to control, .and lapses in go()d
per billion) in the en\'il·onment;d elements becomes cause for concern. (One part
sanitary practice have resulted in minor epidemics of other waterborne diseases.
per billion corresponds to one drop of water in a swimming poolme:lslIring IS i"t
Pollution of the atmosphere has also posed severe health problems Ihat are
wiele, .\0 ft long. and 11 ft deep.)
of great concern to environmental engineers. People in crowded citics have