APES Unit 24 Solid and Hazardous Wastes Municipal solid waste (MSW) consists of solid materials discarded by homes, office buildings, retail stores, restaurants, schools, hospitals, prisons, libraries, and other commercial and institutional facilities. Non Municipal solid waste consists of solid waste generated by industry, agriculture, and mining. A sanitary landfill is the most common method of disposal of solid waste by compacting it and burying it under a shallow layer of soil. The location of a sanitary landfill must take into account he geology of the area, soil drainage properties, the proximity of surface waters and wetlands, and distance from population centers. Despite design features such as high-density plastic liners and leachate collection systems, most sanitary landfills have the potential to contaminate soil, surface water, and groundwater. A mass burn incinerator is a large furnace that burns all solid waste except for unburnable items such as refrigerators. Most mass burn incinerators recover the energy produced rom combustion.
One drawback of incineration is the great expense of installing pollution control devices on the incinerators. These controls reduce the toxicity of the gaseous emissions from incinerators but make the ash that remains behind more hazardous. The three goals of waste prevention are: to reduce the amount of waste, reuse products, and recycle materials as much as possible. Source reduction is an aspect of waste management in which products are designed and manufactured in ways that decrease the volume of solid waste and the amount of hazardous waste in the solid waste stream.
One example of reuse is refillable glass beverage bottles. Recycling involves collecting and reprocessing materials into new products. Many communities recycle paper, glass, metals, and plastic. Integrated waste management is a combination of the best waste management techniques into a consolidated, stems-based program to deal effectively with solid waste. Hazardous waste consists of any discarded chemical that threatens human health or the environment. Dioxins are hazardous chemicals formed as hazardous unwanted by-products during the combustion of many chlorine compounds.
Polychlorinated biphenyls (PCBs) are hazardous, oily, industrial chemicals composed of carbon, hydrogen, and chlorine. Radioactive and chemical wastes have accumulated at numerous US nuclear weapons facilities around the US; the largest, most seriously contaminated site is Hanford Nuclear Reservation in Washington State. The Resource Conservation and Recovery Act (RCRA) instructs the EPA to identify which waste is hazardous and to provide guidelines and standards to states for hazardous waste management programs.
The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), also known as the Superfund Act, addresses the challenge of cleaning up abandoned and illegal hazardous waste sites in the US. Green chemistry is a subdiscipline of chemistry in which commercially important chemical processes are redesigned to significantly reduce environmental harm. Source reduction is the best way to reduce hazardous waste, so green chemists redesign processes with source reduction in mind.