Municipal Solid Waste
Encyclopedia of Public Health | 2002 | Gochfeld, Michael | 700+ words | Copyright MUNICIPAL SOLID WASTE
The estimates of North American garbage production are staggering: The average American disposes of over 3.5 kilograms of trash each day, up more than 50 percent since 1970. The health implications of solid waste include the pollutant burden contributed by various forms of waste management (including incineration, composting, etc.). The "green" approach emphasizes the three Rs: reduction, reuse, and recycling. Alternatives such as incineration and landfills are viewed as unhealthful. However, removal of hazardous materials such as mercury-containing batteries by source separation has had substantial success in reducing toxic emissions from incinerators.
There are many ways to collect garbage, and many ways to process it. Landfills and ocean dumping have long been the mainstay of solid waste management, but these are being phased out. Limitation of disposal options has resulted in long-distance transportation of garbage from urban areas to locales where it can still be disposed of.
THE WASTE STREAM
Solid waste comes from various sources. The following are estimated percentages for New York City. Municipal solid waste (residential, institutional, commercial, and industrial): 55 to 60 percent by weight; construction and demolition waste: 15 to 20 percent (hazardous materials such as asbestos should be separated); sewage sludge: 1 to 2 percent; medical waste (including potentially infectious material): 1 to 2 percent; and harbor debris: less than 1 percent. Dredge spoil can make up to 15 to 20 percent of the waste in a coastal city with a harbor. Other forms of waste that can vary by location include agricultural waste, mining waste, and hazardous waste.
Waste streams differ in the following attributes: (1) physical (e.g., compactibility, density); (2) combustion (temperature, residual ash percentage, heat content in BTUs); (3) chemical composition percentage of nitrogen, carbon, oxygen, chlorine; and concentrations of toxic polyaromatic hydrocarbons (PAHs) and metals; (4) potential for recycling various components; and (5) ease of separation.
A comprehensive waste management program must combine a variety of social, transportation, and treatment technologies. Social issues involve the acceptability of particular programs such as mandatory recycling. Components, in order of desirability, include prevention of wastes at the source; reuse, recycling, or composting; energy recovery; and putting in a landfill only those materials not amenable to other strategies. The plan should consider impacts on air quality, water quality, traffic, noise, odor, socioeconomic effects, and community acceptance.
Developing and evaluating a comprehensive waste management system requires confidence that existing health standards are adequately protective, that all components are maintained and operated according to specifications, and that monitoring and enforcement will work.