Chapter 24 Solid and Hazardous Wastes
Overview of Chapter 24 Solid Waste Waste Prevention Reducing the Amount of Waste Reusing Products Recycling Materials Hazardous Waste Types of Hazardous Waste Management of Hazardous Waste
Solid Waste US generates more solid waste per capita than any other country 2.1 kg per person per day
Types of Solid Waste Municipal solid waste Solid material discarded by homes, office buildings, retail stores, schools, etc. Relatively small portion of solid waste produced Non-municipal solid waste Solid waste generated by industry, agriculture, and mining
Composition of Municipal Solid Waste
Disposal of Solid Waste Three methods Sanitary Landfills Incineration Recycling
Sanitary Landfill
Sanitary Landfill Compacting and burying waste under a shallow layer of soil Most common method of disposal Problems Methane gas production by microorganisms Contamination of surface water & ground water by leachate Not a long-term remedy Few new facilities being opened Closing a full landfill is very expensive
Sanitary Landfill Special Problem: Plastic Much of plastic is from packaging Chemically stable and do not readily break down and decompose Special Problem: Tires Made from materials that cannot be recycled Can be incinerated or shredded
Incineration Volume of solid waste reduced by 90% Produces heat that can make steam to generate electricity Produce less carbon emissions than fossil fuel power plants Byproduct Bottom ash Fly ash
Incineration Types of Incinerators Mass burn (below) Modular Refuse-derived
Composting Municipal Solid Waste Composting Includes: Food scraps, Sewage sludge, Agricultural manure, Yard waste Reduces yard waste in landfills Can be sold or distributed to community
Waste Prevention Three Goals (1) Reduce the amount of waste (2) Reuse products (3) Recycle materials
Reducing Waste Purchase products with less packaging
Reducing Waste Source reduction Products designed and manufactured to decrease the volume of solid waste Pollution Prevention Act (1990) Dematerialization Progressive decrease in the size and weight of a product as a result of technological improvements
Reusing Products Refilling glass beverage bottles Heavier glass that costs more Japan recycles almost all bottles Reused 20 times
Recycling Materials Every ton of recycled paper saves: 17 trees 7000 gallons of water 4100 kwatt-hrs of energy 3 cubic yards of landfill space Recycle Glass bottles, newspapers, steel cans, plastic bottles, cardboard, office paper
Recycling Recycling Paper US recycles 50% Many developed countries are higher Recycling Glass US recycles 25% Costs less than new glass (right)
Recycling Recycling Aluminum Making new can from recycled one costs far less than making a brand new one 49% of aluminum was recycled in 2007 Recycling Metals other than Aluminum Lead, gold, iron, steel, silver and zinc Metallic composition is often unknown Makes recycling difficult
Recycling Recycling Plastic 12% of all plastic was recycled in 2007 Less expensive to make from raw materials 37% of PET was recycled in 2007 Mostly water and soda bottles
Recycling Recycling Tires Few products are made from old tires Playground equipment Trashcans Garden hose Carpet Roofing materials 36% of tires are currently recycled to make other products
Integrated Waste Management
Hazardous Waste Any discarded chemical that threatens human health or the environment Reactive, corrosive, explosive or toxic chemicals Types of Hazardous Waste Dioxins PCBs Radioactive waste Love Canal Toxic Waste Site
Hazardous Waste
Case-In-Point Hanford Nuclear Reservation
Management of Hazardous Waste Chemical accidents National Response Center notified Typically involves oil, gasoline or other petroleum spill Current Management Policies Resource Conservation and Recovery Act (1976, 1984) Comprehensive Environmental Response, Compensation, and Liability Act (1980) Commonly known as Superfund
Superfund Program Cleaning up existing hazardous waste: 400,000 waste sites Leaking chemical storage tanks and drums (right) Pesticides dumps Piles of mining wastes Must be cleaned up
Management of Hazardous Waste Superfund National Priorities List 2009: 1,264 sites on the list States with the greatest number of sites New Jersey (114) California (94) Pennsylvania (94) New York (85) Michigan (65)
Management of Hazardous Waste Biological Treatment of Hazardous Chemicals Bioremediation - use of bacteria and other microorganisms to break down hazardous waste into relatively harmless products Time consuming Phytoremediation - use of plants to absorb and accumulate hazardous materials in the soil Ex: Indian mustard removed heavy metals
Examples of Phytoremediation
Management of Hazardous Waste (1) Source reduction (2) Conversion to less hazardous materials (3) Long-term storage
Hazardous Waste Landfill