Partll Solid Waste Engineering 12 Evolution of Solid Waste Management Solid wastes comprise all the wastes arising from human and animal activities that are normally solid and that are discarded as useless or unwanted. The term solid waste as used in this text is all-inclusive encompassing the heterogeneous mass of throwaways from the urban community as well as the more homogeneous accumulation of agricultural, industrial, and mineral wastes. This book is focused on the urban setting, where the accumulation of solid wastes is a direct consequence of life 12.1 Solid Waste-a Consequence of Life From the days of primitive society, humans and animals have used the resources of the earth to support life and to dispose of wastes. In early times, the disposal of human and other wastes did not pose a significant problem, for the population was small and the amount of land available for the assimilation of wastes was large. Although emphasis is currently being placed on recycling the energy and fertilizer values of solid wastes, the farmer in ancient times probably made a bolder attempt at this Indications of recycling may still be seen in the primitive, yet sensible, agricultural practices in many of the developing nations where farmers recycle solid wastes for fuel or fertilizer values Problems with the disposal of wastes can be traced from the time when humans first began to congregate in tribes. villages, and communities and the accumulation of wastes became a consequence of life. Littering of food and other solid wastes in medieval towns-the practice of throwing wastes into the unpaved streets, roadways, and vacant land-led to the breeding of rats, with their attendant fleas carrying bubonic plague. The lack of any plan for the management of solid wastes thus led to the epidemic of plague, the Black Death, that killed half of the fourteenth-century Europeans and caused many subsequent epidemics with high death tolls. It was not until the nineteenth century that public health control measures became a vital consideration to public officials, who began to realize that food wastes had to be collected and disposed of in a sanitary manner to control rodents and flies, the vectors of disease The relationship between public health and the improper storage, collection, and disposal of solid wastes is quite clear. Public health authorities have shown that rats, flies, and other disease vectors breed in open dumps, as well as in poorly constructed or poorly maintained housing, in food storage facilities, and in many other places where food and harborage are available for rats and the insects associated with them cological phenomena such as water and air pollution have also been attributed to improper management of solid wastes. For instance, liquid from dumps and poorly engineered landfills has contaminated surface waters and groundwaters. In mining areas the liquid leached from waste dumps may contain toxic elements, such as copper, arsenic, and uranium, or it may contaminate water supplies with unwanted salts of calcium and magnesium. Although nature has the capacity to dilute, disperse, degrade, absorb, or otherwise reduce the impact of unwanted residues in the atmosphere, in the waterways, and on the land, ecological imbalances have occurred where the natural assimilative capacity has been exceeded 12.2 Waste Generation In a Technological Society The development of a technological society in the United States can be traced to the beginnings of the Industrial Revolution in Europe, unfortunately, so can a major increase in solid waste disposal problems. In fact, in the latter part of the nineteenth century, conditions were so bad in England that an urban sanitary act was passed in 1888 prohibiting the throwing of solid wastes into ditches, rivers, and waters. This preceded by about ll years the enactment of the Rivers and Harbors Act of 1899 in the United States, which was intended to regulate the dumping of debris in navigable waters and adjacent lands Thus, along with the benefits of technology have al so come the problems associated with the dispo of the resultant wastes. To understand the nature of these problems, it will be helpful to12-1 PartIII Solid Waste Engineering 12 Evolution of Solid Waste Management Solid wastes comprise all the wastes arising from human and animal activities that are normally solid and that are discarded as useless or unwanted. The term solid waste as used in this text is all-inclusive, encompassing the heterogeneous mass of throwaways from the urban community as well as the more homogeneous accumulation of agricultural, industrial, and mineral wastes. This book is focused on the urban setting, where the accumulation of solid wastes is a direct consequence of life. 12.1 Solid Waste—a Consequence of Life From the days of primitive society, humans and animals have used the resources of the earth to support life and to dispose of wastes. In early times, the disposal of human and other wastes did not pose a significant problem, for the population was small and the amount of land available for the assimilation of wastes was large. Although emphasis is currently being placed on recycling the energy and fertilizer values of solid wastes, the farmer in ancient times probably made a bolder attempt at this. Indications of recycling may still be seen in the primitive, yet sensible, agricultural practices in many of the developing nations where farmers recycle solid wastes for fuel or fertilizer values. Problems with the disposal of wastes can be traced from the time when humans first began to congregate in tribes, villages, and communities and the accumulation of wastes became a consequence of life. Littering of food and other solid wastes in medieval towns－the practice of throwing wastes into the unpaved streets, roadways, and vacant land—led to the breeding of rats, with their attendant fleas carrying bubonic plague. The lack of any plan for the management of solid wastes thus led to the epidemic of plague, the Black Death, that killed half of the fourteenth-century Europeans and caused many subsequent epidemics with high death tolls. It was not until the nineteenth century that public health control measures became a vital consideration to public officials, who began to realize that food wastes had to be collected and disposed of in a sanitary manner to control rodents and flies, the vectors of disease. The relationship between public health and the improper storage, collection, and disposal of solid wastes is quite clear. Public health authorities have shown that rats, flies, and other disease vectors breed in open dumps, as well as in poorly constructed or poorly maintained housing, in food storage facilities, and in many other places where food and harborage are available for rats and the insects associated with them. Ecological phenomena such as water and air pollution have also been attributed to improper management of solid wastes. For instance, liquid from dumps and poorly engineered landfills has contaminated surface waters and groundwaters. In mining areas the liquid leached from waste dumps may contain toxic elements, such as copper, arsenic, and uranium, or it may contaminate water supplies with unwanted salts of calcium and magnesium. Although nature has the capacity to dilute, disperse, degrade, absorb, or otherwise reduce the impact of unwanted residues in the atmosphere, in the waterways, and on the land, ecological imbalances have occurred where the natural assimilative capacity has been exceeded. 12.2 Waste Generation In a Technological Society The development of a technological society in the United States can be traced to the beginnings of the Industrial Revolution in Europe; unfortunately, so can a major increase in solid waste disposal problems. In fact, in the latter part of the nineteenth century, conditions were so bad in England that an urban sanitary act was passed in 1888 prohibiting the throwing of solid wastes into ditches, rivers, and waters. This preceded by about 11 years the enactment of the Rivers and Harbors Act of 1899 in the United States, which was intended to regulate the dumping of debris in navigable waters and adjacent lands. Thus, along with the benefits of technology have also come the problems associated with the disposal of the resultant wastes. To understand the nature of these problems, it will be helpful to examine the