1、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 con
2、trol 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 sta
3、te 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
4、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 f
5、orm, 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
6、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
7、 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 design
8、ed 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 the
9、se 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 dia
10、posal, 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 emis
11、sion 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,
12、 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
13、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 extremes from climates and as living apace The building of fast and rel
14、iable 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 wor
15、ld 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 i
16、mprovements, however, have come disturbing side effects, such as lost arable land, disappearing forests, environmental pollution, and new organisms resistant tocontrols. Many effects originally considered to be just nuisances are now recognized as potential threats to nature and to humana. In an agr
17、arian society, people lived essentially in harmony with nature, raising food, gathering firewood, and making clothing and tools from the land. The wastes from animals and humans were returned to the soil as fertilizer. Few, if any, problems of water, land, or air pollution occurred.The cities of anc
18、ient times, particularly those of the Roman Empire had systems to supply water and to dispose of wastes. The aqueducts supplying the ancient city of Rome (population about 1 million) with safe water from the Cloaca Maxims, the best known and one of the earliest sewers to be built, are examples of su
19、ch systems. The municipal technology of ancient cities seems to have been forgotten for many centuries by those who built cities throughout Europe. Water supply and waste disposal were neglected, resulting in many outbreaks of dysentery, cholera, typhoid. and other waterborne diseases. Until the mid
20、dle of the nineteenth century, it was not realized that improper wastes disposal polluted water supplies with disease-carrying organisms. The industrial revolution in nineteenth- century Britain, Europe, and North Americs aggravated the environmental problems since it brought increased urbanization
21、with the industrialization. Both phenomena, urbanization and industrialization, were and are fundamental causes of water and air pollution which the cities of that time were unable to handle.Rapid advances in technology for the treatment of water and the partial treatment of wastewater took place in
22、 the developed countries over the next few decades. This led to a dramatic decrease in the incidence of waterborne diseases. Note that all wastes discharge into the environment, and thus pollute our water, air, and land systems.Unit 2Text: Historical Overview of Hazardous Substance Disposal in the U
23、SAHazardous substance disposal practices in the United States have traveled full circle. Prior to 1978 there were few if any regulations regarding the disposal of these materials. Improper disposal of many of these chemicals resulted in health problems for many citizens, contaminated water supplies,
24、 and destruction of wildlife. With the enactment of the Resource Conversation and Recovery Act (RCRAY1 of 1978, manufacturing facilities now have an obligation to account for all waste materials that are generated by the facility. Implementation of RCRA has been slow.From the very early industrial p
25、eriod in the United Statea, which started about 1920, until several years after the Second World Wsr, there was little concern for the proper methods of disposal of waste materials that were generated as by-products during manufacturing processes. Up until the 1960a it was quite common to find fresh
26、 water rivers and streams fouled with waste chemicals from manufacturing, salt water from oil production wells and waste acids from steel mill activities. Virtually every conceivable waste oil, solvent, or resin waste could be found in the rivers. The laws of the time were either non-existent or not
27、 enforced. The literature has many examples of health problems of individuals as well as destruction of fish and wildlife habitat. Many other cases occurred that were not reported in the literature.Other waste materiala were dumped haphazardly in makeshift excavations either at the factory side or t
28、hroughout the country aide. Because of ignorance and lack of economic incentives to do so, the factories made no attempt to prevent contamination of underground water supplies by the chemicals that were disposed of. In fact, knowledgeable scientists of the time accepted land irrigation and percolati
29、on into the porous underground formations as methods of waste treatment. Although these treatment methods may have been intended for non-hazardous materiala, they were employed for hazardous materials as well. Again, there were no governmental regulations protecting the underground aquifers from the
30、se practices.The problem of disposal of hazardous chemicals did not improve with the creation of the Environmental Protection Agency (EPA)in 1966. The first task of the new agency was to clean up rivera and streams. Unfortunately, no one in power in the government at the time had insight into the pr
31、oblema that were to be created by the new agency.The EPA waa quite successful in those early days in the enforcement of the many water pollution laws that evolved. As the practice of the dumping of hazardous materials into the rivers and streams was eliminated, those same materials created other dis
32、posal problems.Many of the chemicals saved from the sewer were either worthlesa or of such a low value as to render recovery uneconomical, In some cases, recovery was technically impossible. Asa result, the waste chemicals were disposed of by any convenient method. The makeshift dumps sites were exp
33、anded. Because there were no regulations regarding disposal, persons with no technical expertise entered into the business of waste disposal. The profits were high because these individuals did not treat the chemicals. In mosr cases, the waste materials were transported to impounding areas located o
34、n privately owned land.The factories that generated the waste felt secure in the belief that the waste transporter was disposing of the materials in an acceptable manner. In most cases, this was not a correct assumption.The unregulated dumps grew both in size and complexity. When the dumps wcre in c
35、lose proximity to populated areas or public water supplies, a series of problems begin to develop. Citizens in the vicinity of some of the dumps began to experience adverse health problems such as akin rashes, paralysis, cancer, and birth defects. In some cases, these problems have been attributed t
36、o contamination from the chemicals.Because of these concerns, the United States Congress enacted a new legislation that dealt with the isauea of disposal of hazardous wastes. This was the Resource Conversation and Recovery Act of 1978. The purpose of the Act was to allow regulation of hazardous subs
37、tance disposal. As a result, industries that generated large quantities of these waste materials now had to ensure that the materials were disposed of in the a manner that was safe for the environment.Many of the improper dumps that were created prior to the RCRA legislation were created by persons
38、with little or no financial resources. As a result, the cleanup of the old aides has been taken over by the government under legialation. As of this time, the results of these clean up efforts have been ineffective.Because of the abuses and problems of the past, regulations have been enacted that fo
39、rce American industry to be responaible for hazardous waste disposal. The problems were brought about by a lack of economic incentives to the industrial community. The problems were compounded by the inexperience and lack of insight by elected governmental officials and the governmental agencies cha
40、rged with the task of regulation. Although sufficient legislation is now in place to solve the problem of hazardous waste disposal, it is unlikely that a true solution will be achieved for 20 years or longer. Only through interaction between industry, scientists, and government regulators will true
41、solutions be finally realized.Unit 3Text: What is Waste Reduction/Waste Minimization?A great amount of time has been spent in the U. S. discussing the terminology of such words as source reduction, waste minimization, recycling and pollution prevention. EPA has provided the following definitions.Sou
42、rce reduction. Any action that reduces the amount of waste exiting a process. This includes, for example, process changes, feedstock changes, improved housekeeping/management, and in-process recycling.Waste minimization. The reduction to the extent feasible, of waste that is generated or suhsequentl
43、y treated, stored, or disposed of. It includes any source reduction or recycling activity undertaken by a generator that results in either the reduction of the total volume or quantity of waste or the reduction in the toxicity of waste (or both) as long as the reduction is consistent with the goal o
44、f minimization of present and future threats to human health and the environment.Recycling. The use or reuse of a waste as a substitute for a commercial product or as a feedstock to an industrial process. This includes the on-or off-site reclamation of useful fractions of a waste or the removal of c
45、ontaminants from a waste to allow reuse.Pollution prevention. Pollution may be generated during manufacturing, or when certain products are used commercially or by consumers. This may be prevented in three ways:changing inputs/reducing reliance on toxic or hazardous raw materials; process changes/in
46、creasing efficiency/improved maintenance such as equipment modifications, better housekeeping, in-process closed-loop recycling; or changing outputs/reducing reliance on toxic or hazardous products.With the passage of the Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery
47、 Act in 1984, the U. S. Congress established a national policy declaring the importance of reducing or eliminating the generation of hazardous waste.The Congress hereby declares it to be a national policy of United States that wherever feasible, the generation of hazardous waste is to be reduced or
48、elimioated as expeditiously as possible. Waste that is nevertheless generated should be treated, stored, or disposed of so as to minimize present sod future threat to human health and the environment.In 1990, the U. S. Congress passed the Pollution Prevention Act, establishing a hierarchy of waste m
49、anagement as national policy; stating that first pollution should he prevented or reduced wherever feasible; second, waste should be recycled in an environmentally safe manoer; third, waste should be treated; and as a last resort, waste should be disposed of or released to the environment. With the passage of these sod other environmental laws, waste minimization has become an important operating philosophy in the United States.Waste Reduction/Wast
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