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