PART 1 INTRODUCTION TO ENVIRONMENTAL ENGINEERINGUnit 1Text: Environmental EngineeringWhat Is This Book About?The objective of this book is to introduce engineering and science students to the interdisciplinary study of enviroomentsl problems: their causes, why they sre of concern, and how we csn control them. The book includes:? Description of what is meant by environment snd by environmental systems? Information on the basis causes of environmental disturbances? Basis scientific knowledge necessary to understand the nature of environmental problems and to be able to quantify them? Current state of the technology environmental control in its application to water, air and pollution problems? Considerable gaps in our current scientific knowledge of understanding and controlling many of the complex interactions between human activities and nature? Many environmental problems which could be eliminated or reduced by the application of current technology, but which are not dealt with because of societys lack of will to do so, or in many instances because of a lack of resources to do so.Some Important DefinitionsWhere they are first used in this book, definitions are introduced in block form, as shown here, or printed in bold type.Environment is the physicsl and biotic habitat which surrounds us; that which we can see. hear, touch, smell, and taste.System. according to Wehster s dictionaryD , is defined as “a set or arrangement of things so related or connected as to form a unit or organic whole; as, a solar system, irrigation system, supply system, the world or universe”.Pollution can be defined as an undesirable change in the physical, chemical, or biological characteristics of the air, water, or land that can harmfully affect the health, survival, or activities of humans or other living organisms.When the goal of improving environmental quality is taken to be improving human wellbeing. the word “environment” broadens to include all kinds of social, economic, and cultural aspects. Such broadness is unworkable in many real situations and impractical in a textbook designed for a one-semester course. Our examination of environmental problems is therefore limited by our definition of “environment”.Interaction of SystemsA number of different environmental problems are associated with water, air, or land systems. Many of these problems will apply only within one of these systems, justifying the breakdown into these categories. Such a classification is also useful for easier comprehension of related problems within one system. Moreover, it is sensible because, for managerial and administrative reasons , such subfields as air pollution, water supply, wastewater diaposal, and solid waste disposal are often dealt with separately by governmental agencies.Unfortunately, many important environmental problems are not confined to an air, water, or land system, but involve interactions between systems. A current example is the acid rain problem stemming from the emission of sulfur dioxide and nitrogen oxide gases into the atmosphere from the stacks of generating stations, smelters, and automobile exhausts. These gases are then transported by air currents over wide regions, Rainfall “washes them out”, creating acid rain which is harmful to aquatic life, forests, and agricultural crops. Two examples of interaction between systems that cause major environmental disturbances are presented-the buildup of atmospheric carbon dioxide, a global problem. and the acid rain problem. normally of regional nature.Environmental DisturbancesMany major improvements to our standard of living can be attributed to the application of science and technology. A few examples are noted here. Can you think of others? The production of more and better quality food The creation of housing as protection from extrcmcs from climates and as living apace The building of fast and reliable means of transportation The invention of various systems of communication The invention of machines to replace human or animal power The supply of safe water and the disposal of wastes The elimination of many infectious diseases The elimination of most water-borne diseases in the developed world through improved water technology The availability of leisure time through greater productivity, providing the opportunity for cultural and recreational activities The protection from the worst effects of natural disasters such as floods, droughts, earthquakes, and volcanic eruptions.With these improvements, however, have come disturbing side effects, such as lost arabic land, disappearing forests, environmental pollution, and new organisms resistant tocontrols. Many effects originally considered to be just nuisances are now recognized as potential threata to nature and to humana. In an agrarian society, people lived essentially in harmony with mature, raising food, gathering firewood, and making clothin