characteristic is used to refer to a group of constituents, such as physical or biological characteristics The term "sludge"has been used for many years to signify the residuals produced from wastewater treatment, in 1994, the Water Environment Federation adopted a policy defining"biosolids as a primarily organic,solid wastewater treatment product that can be recycled beneficially. In this policy, "solids"are defined as the residuals that are derived from the treatment of wastewater Solids that have been treated to the point at which they are suitable for beneficial use are termed"biosolids. In this text. the terms of solids and biosolids are used extensively, but"" continues to be used. especially in cases where 1-2 Impact of Regulations on Wastewater Engineering From about 1900 to the early 1970s, treatment obiectives were concerned primarily with(1) the removal of colloidal, suspended, and floatable material. (2)the treatment of biodegradable organics, and(3) the elimination of pathogenic organisms. Implementation in the United States of the Federal Water Pollution Control Act Amendments of 1972(Public Law 92-500). also known as the Clean Water Act(CWA stimulated substantial changes in wastewater treatment to achieve the obiectives of "fishable and swimmable"waters. Unfortunately, these objectives were not uniformly m From the early 1970s to about 1980, wastewater treatment objectives were based primarily on aesthetic and environmental concerns. The earlier objectives involving the reduction of biological oxygen demand ( BOD), total suspended solids(TSs), and pathogenic organisms continued but at higher levels. Removal of nutrients, such as nitrogen and phosphorus, also began to be addressed, particularly in some of the inland streams and lakes, and estuaries and bays. Major programs were undertaken by both state and federal agencies to achieve more effective and widespread treatment of wastewater to improve the quality of the surface waters. These programs were based on(D) an increased understanding of the environmental effects caused by wastewater discharges:(2)a greater appreciation of the adverse long-term effects caused by the discharge of some of the specific constituents found in wastewater: and(3 )the development of national concern for the protection of the environment. As a result of these programs, significant improvements have been made the quality of the surface waters Table I-I Terminology ly used in the field of wastewater engineerin I Definition Biosolids Primarily an organic, semisolid wastewater product that remains after solids are stabilized biologically or chemically and are suitable far beneficial use Class a biosolids Biosolids in which the pathogens are reduced below current dete Class a biosolids Biosolids in which the pathogens are reduced to levels that are unlikely to pose a threat to the public health and the environment under specific use conditions. Class b biosolids cannot be sold or given away in bags or other containers or applied on lawns or home gardens Characteristics General classes of wastewater constituents such as physical, chemical (wastew biological and biochemical Composition The makeup of wastewater, including the physical, chemical, and Constituents Individual components, elements, or biological entities such as Contaminants Disinfection Reduction of disease-causing microorganisms by physical or chemical Effluent The liquid discharged from a processing step Constituents added to the water supply through use Non-point sources Sources of pollution that originate from multiple sources over a relatively large area Nutrient An element that is essential for the growth of plants and animals Nutrients in wastewater, usually nitrogen and phosphorus, may cause unwanted algal and plant growths in lakes and streams Point sources Pollutional loads discharged at a specific location from pipes, outfalls. 1-21-2 characteristic is used to refer to a group of constituents, such as physical or biological characteristics. The term “sludge” has been used for many years to signify the residuals produced from wastewater treatment, in 1994, the Water Environment Federation adopted a policy defining "biosolids' as a primarily organic, solid wastewater treatment product that can be recycled beneficially. In this policy, “solids” are defined as the residuals that are derived from the treatment of wastewater. Solids that have been treated to the point at which they are suitable for beneficial use are termed “biosolids.” In this text, the terms of solids and biosolids are used extensively, but “sludge” continues to be used, especially in cases where untreated solid material and chemical residuals are referenced. 1-2 Impact of Regulations on Wastewater Engineering From about 1900 to the early 1970s, treatment objectives were concerned primarily with (1) the removal of colloidal, suspended, and floatable material, (2) the treatment of biodegradable organics, and (3) the elimination of pathogenic organisms. Implementation in the United States of the Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500), also known as the Clean Water Act (CWA), stimulated substantial changes in wastewater treatment to achieve the objectives of “fishable and swimmable”waters. Unfortunately, these objectives were not uniformly met. From the early 1970s to about 1980, wastewater treatment objectives were based primarily on aesthetic and environmental concerns. The earlier objectives involving the reduction of biological oxygen demand (BOD), total suspended solids (TSS), and pathogenic organisms continued but at higher levels. Removal of nutrients, such as nitrogen and phosphorus, also began to be addressed, particularly in some of the inland streams and lakes, and estuaries and bays. Major programs were undertaken by both state and federal agencies to achieve more effective and widespread treatment of wastewater to improve the quality of the surface waters. These programs were based, in part, on (1) an increased understanding of the environmental effects caused by wastewater discharges; (2) a greater appreciation of the adverse long-term effects caused by the discharge of some of the specific constituents found in wastewater; and (3)the development of national concern for the protection of the environment. As a result of these programs, significant improvements have been made in the quality of the surface waters. Table 1-1 Terminology commonly used in the field of wastewater engineering Term Definition Biosolids Primarily an organic, semisolid wastewater product that remains after solids are stabilized biologically or chemically and are suitable far beneficial use Class A biosolids Biosolids in which the pathogens are reduced below current detectable levels Class A biosolids Biosolids in which the pathogens are reduced to levels that are unlikely to pose a threat to the public health and the environment under specific use conditions. Class B biosolids cannot be sold or given away in bags or other containers or applied on lawns or home gardens Characteristics (wastewater) General classes of wastewater constituents such as physical, chemical, biological, and biochemical Composition The makeup of wastewater, including the physical, chemical, and biological constituents Constituents Individual components, elements, or biological entities such as suspended solids or ammonia nitrogen Contaminants Constituents added to the water supply through use Disinfection Reduction of disease-causing microorganisms by physical or chemical means Effluent The liquid discharged from a processing step Impurities Constituents added to the water supply through use Non-point sources Sources of pollution that originate from multiple sources over a relatively large area Nutrient An element that is essential for the growth of plants and animals. Nutrients in wastewater, usually nitrogen and phosphorus, may cause unwanted algal and plant growths in lakes and streams Parameter A measurable factor such as temperature Point Sources Pollutional loads discharged at a specific location from pipes, outfalls