Empty plastic bottles, yesterday’s newspapers, eggshells, or used tea bags—all of these have one thing in common: they belong tomunicipal solid waste (MSW), ordinarily called “trash” or “garbage”. MSW refers to household, office, or retail waste and is part of everyone’s daily life. Each person in the United States generates 2 kg of MSW every day, which resulted in a total waste creation of 254 million tons (t)1 in 2013, and the trend is rising. As the volume of waste produced in the United States continues to increase, the handling and disposal of MSW are growing concerns of society. [1, 2, 3] In order to understand the impact of plastics and their recycling in the waste stream, it is important to understand the composition of MSW and current strategies for handling it.
| 1.1 | Municipal Solid Waste—A Daily Companion |
Municipal solid waste (MSW) is generally defined as nonhazardous waste. The United States Environmental Protection Agency (EPA) characterizes MSW as“waste consisting of everyday items, used and then thrown away, such as product packaging, bottles, food scraps and newspapers which comes from homes, schools, hospitals and businesses.” MSW is classified in three broad categories according to where it is generated: household waste, commercial waste, and institutional waste. [4, 5] Household waste includes that from single- and multiple-family homes, hotels and motels, and day-use recreation areas. This category accounts for 55 to 65 % of the total MSW generated and is also referred to as postconsumer waste. Thus, households are the primary source of MSW in the United States. Commercial waste includes solid waste from stores, offices, restaurants, warehouses, and other nonmanufacturing activities. Waste from schools, colleges, and similar public or quasi-public buildings is listed as institutional waste. The waste generated by the industrial sector is negligible. Manufacturing companies manage their solid residues or preconsumer waste by recycling, direct reuse, or self-disposal in industrial waste landfills. [1, 4, 5]
The total MSW generation in the United States increased steadily between 1960 and 2013, from 88 t/year (tons per year) to 254 t/year, due to economic expansion. The generation per capita per year has risen from 1.2 kg to 2 kg. However, it is important to note that after a peak in 2000, the MSW produced per capita per year has decreased slightly since then (2.15 kg to 2 kg). [2] Factors affecting the quantity of MSW generated include changes in population, individual purchasing power, product packaging, and technology, which again affect disposal habits as well as the nature of materials disposed. Hence, an analysis of the MSW composition over time is necessary to explain and also forecast future MSW generation in the United States. [4] The EPA uses two methods to characterize MSW, by material and by major products. In order to understand the studies presented in this book, knowledge of the proportion and quantity of different materials in MSW (Figure 1.1) is important and reflects the changes described in MSW generated in the United States.
Figure 1.1 Comparison of the types and amounts of plastic waste generated in the United States in 1960 and 20132
Figure 1.1 provides information about the trends in consumer behavior and production of waste as seen, for example, in the significant change in the proportion of plastics in MSW between 1960 and 2013, which will be further discussed inChapter 2. In this chapter we will discuss how the composition of MSW is of particular relevance for waste handling.
| 1.2 | Management Methods for Municipal Solid Waste |
The United States manages wastes in three different ways:
Figure 1.2 shows a flowchart of this waste management system. Due to a growing awareness of environmental pollution, the EPA has strived to recycle as much MSW as possible or at least to burn it for energy, which will be furthe
