13 Sources, Types, and Composition of Municipal Solid Wastes Solid wastes include all solid or semisolid materials that the possessor no longer considers of sufficient value to retain. The management of these waste materials is the fundamental concern of all the activities encompassed in solid waste management-whether the planning level is local, regional or subregional, or state and federal. For this reason, it is important to know as much about municipa solid waste (MS W) as possible. The purpose of this chapter is to identify the sources, types, and composition of solid wastes 13-1 Sources of solid wastes Knowledge of the sources and types of solid wastes, along with data on the composition and rates of generation, is basic to the design and operation of the functional elements associated with the management of solid wastes. To avoid confusion, the term refuse, often used interchangeably with the term solid wastes. is not used in this text Sources of solid wastes in a community are, in general, related to land use and zoning. Although any number of source classifications can be developed, the following categories are useful: (1) residential. 2)commercial. (3) institutional (4) construction and demolition.(5)municipal services. (6)treatment lant sites. 7) industrial and (8 13.2 Types of Solid Wastes As a basis for subsequent discussions, it will be helpful to define the various types of solid wastes that are generated. It is important to be aware that the definitions of solid waste terms and the classifications vary greatly in the literature and in the profession. Consequently, the use of published data requires considerable care, judgment, and common sense. The following definitions are intended to serve as a guide and are not meant to be precise in a scientific sense Residential and commercial Residential and commercial solid wastes, excluding special and hazardous wastes discussed below consist of the organic(combustible) and inorganic (noncombustible) solid wastes from residential areas and commercial establishments. Typically, the organic fraction of residential and commercial solid waste consists of materials such as food waste (also called garbage), paper of all types corrugated cardboard (also known as paperboard and corrugated paper), plastics of all types, textiles, ubber, leather, wood, and yard wastes. The inorganic fraction consists of items such as glass, crocker tin cans, aluminum, ferrous metals, and dirt. If the waste components are not separated when discarded. then the mixture of these wastes is also known as commingled residential and commercial MSW Wastes that will decompose rapidly, especially in warm weather, are also known as putrescible waste The principal source of putrescible wastes is the handling, preparation, cooking, and eating of foods Often, decomposition will lead to the development of offensive odors and the breeding of flies. In many locations, the putrescible nature of these wastes will influence the design and operation of the solid waste collection system Although there are more than 50 classifications for paper, the waste paper found in msw is typically composed of newspaper, books and zines, commercial printing, office paper, other paperboard, paper packaging, other nonpackaging paper, tissue paper and towels, and corrugated cardboard The plastic materials found in MSw fall into the following seven categories: Polyethylene terephthalate(PeTE/l High-density polyethylene(HDPE/2) Polyvinyl chloride(Pvc/3) Low-density polyethylene (LDPE/4) Polypropylene(PP/5 Polystyrene(PS/6 Other multilayered plastic materials(7) PETE HDPE LDPE PS OTHER Fig13-1. Code designation used for vavious types of plastics 13-113-1 13 Sources, Types, and Composition of Municipal Solid Wastes Solid wastes include all solid or semisolid materials that the possessor no longer considers of sufficient value to retain. The management of these waste materials is the fundamental concern of all the activities encompassed in solid waste management—whether the planning level is local, regional or subregional, or state and federal. For this reason, it is important to know as much about municipal solid waste (MSW) as possible. The purpose of this chapter is to identify the sources, types, and composition of solid wastes. 13-1 Sources of Solid Wastes Knowledge of the sources and types of solid wastes, along with data on the composition and rates of generation, is basic to the design and operation of the functional elements associated with the management of solid wastes. To avoid confusion, the term refuse, often used interchangeably with the term solid wastes, is not used in this text. Sources of solid wastes in a community are, in general, related to land use and zoning. Although any number of source classifications can be developed, the following categories are useful: (1) residential, (2) commercial, (3) institutional, (4) construction and demolition, (5) municipal services, (6) treatment plant sites, (7) industrial, and (8) agricultural. 13-2 Types of Solid Wastes As a basis for subsequent discussions, it will be helpful to define the various types of solid wastes that are generated. It is important to be aware that the definitions of solid waste terms and the classifications vary greatly in the literature and in the profession. Consequently, the use of published data requires considerable care, judgment, and common sense. The following definitions are intended to serve as a guide and are not meant to be precise in a scientific sense. Residential and Commercial Residential and commercial solid wastes, excluding special and hazardous wastes discussed below, consist of the organic (combustible) and inorganic (noncombustible) solid wastes from residential areas and commercial establishments. Typically, the organic fraction of residential and commercial solid waste consists of materials such as food waste (also called garbage), paper of all types, corrugated cardboard (also known as paperboard and corrugated paper), plastics of all types, textiles, rubber, leather, wood, and yard wastes. The inorganic fraction consists of items such as glass, crockery, tin cans, aluminum, ferrous metals, and dirt. If the waste components are not separated when discarded, then the mixture of these wastes is also known as commingled residential and commercial MSW. Wastes that will decompose rapidly, especially in warm weather, are also known as putrescible waste. The principal source of putrescible wastes is the handling, preparation, cooking, and eating of foods. Often, decomposition will lead to the development of offensive odors and the breeding of flies. In many locations, the putrescible nature of these wastes will influence the design and operation of the solid waste collection system . Although there are more than 50 classifications for paper, the waste paper found in MSW is typically composed of newspaper, books and magazines, commercial printing, office paper, other paperboard, paper packaging, other nonpackaging paper, tissue paper and towels, and corrugated cardboard. The plastic materials found in MSW fall into the following seven categories: • Polyethylene terephthalate (PETE/I) • High-density polyethylene (HDPE/2) • Polyvinyl chloride (PVC/3) • Low-density polyethylene (LDPE/4) • Polypropylene (PP/5) • Polystyrene (PS/6) • Other multilayered plastic materials (7) Fig13-1. Code designation used for vavious types of plastics