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Solid Waste

Solid Waste. Chapter 21 16th ed. MSW. 1.5% of total waste stream 30% of MSW is recycled or composted, 55% landfilled, 15% burned in incinerator 3M company reduced solid waste by 70%, saved 750 million. Solid Waste Problems. Plastic vs paper grocery bags

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Solid Waste

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  1. Solid Waste Chapter 21 16th ed

  2. MSW • 1.5% of total waste stream • 30% of MSW is recycled or composted, 55% landfilled, 15% burned in incinerator • 3M company reduced solid waste by 70%, saved 750 million

  3. Solid Waste Problems • Plastic vs paper grocery bags • Less energy, less landfill space vs renewable resource, less danger if swallowed (cloth is best) • Disposable vs cloth diapers • Manufacuring, landfill vs cleaning effects • Tires (250 million discarded each year) • 2.5 to 4 billion used tires are in US

  4. Ways to Reduce • Reduce use • Redsign manufacturing process • Trash taxes (Denmark) • Pay as you throw (trash bags)

  5. Reuse • Denmark, Finland, and Prince Edward Island have banned beverage containers that can’t be reused • San Francisco has banned the use of plastic shopping bags

  6. Recycling • Composting • MSW= 50% recycled in Switzerland, Japan 25 % in US • Turn periodically to raise temp, kill pathogens and weed seeds • Siting plants is difficult (NIMBY) • Primary (closed loop) vs secondary recycling

  7. Recycling (cont) • Germany: take back packaging; Taiwan: TVs computers; Netherlands: no pckg in landfill • Sell service instead of goods (Xerox)

  8. Recycling paper • High quality is available • 2000, US recycled 49% of wastepaper • Chlorine used to bleach, hydrogen peroxide and ozone are replacing chlorine • Recycled from preconsumer vs post consumer waste

  9. Materials -recovery facilities • Large scale (480 in US) • Separate, recycle or burn (electricity) • Ash to landfill • Source separation ( home or business) has advantages Aluminum is valuable

  10. Plastics • 4% of US plastic is recycled • Difficult to recycle b/c many different, incompatible layers of resins are used (except PET (polyethylene terephthalate) in 2 liter bottles, 20% is recycles) • Coca-Cola announced goal to recycle 100% of PET bottles

  11. Fig. 21-10, p. 570

  12. Detoxifying Hazardous Waste • Bioremediation uses specialized bacteria • Phytoremediation uses plants • Plasma torch • High temp: decomposes organic molecules to atoms or simple cmpds

  13. Incinerators • Temperatures up to 3,600oF • 16% of MSW is burned • 170 incinerators in US

  14. Electricity Smokestack Turbine Steam Crane Generator Wet scrubber Furnace Boiler Electrostatic precipitator Water added Waste pit Bottom ash Dirty water Conveyor Fly ash Ash for treatment, disposal in landfill, or use as landfill cover Fig. 21-13, p. 575

  15. When landfill is full, layers of soil and clay seal in trash Topsoil Electricity generator building Sand Clay Leachate treatment system Methane storage and compressor building Garbage Probes to detect methane leaks Pipes collect explosive methane for use as fuel to generate electricity Methane gas recovery well Leachate storage tank Compacted solid waste Groundwater monitoring well Leachate pipes Leachate pumped up to storage tank for safe disposal Garbage Sand Synthetic liner Leachate monitoring well Groundwater Sand Clay and plastic lining to prevent leaks; pipes collect leachate from bottom of landfill Clay Subsoil

  16. Sanitary Landfill • 55% of waste in US is landfilled • Sand, clay layers around synthetic liner • Leachate is pumped from bottom, sent to water treatment plant • Except for Phila, NYC no shortage of space • Methane (anaerobic decomp) can be collected (Tullytown, PA)

  17. Disposal of Hazardous Waste • Deep-well injection: liquid pumped under pressure into porous rock • Surface impoundments: ponds, pits or lagoons. 70% have no liners • Secure hazardous waste landfill (monitored) • Above ground building

  18. Fig. 21-18, p. 579

  19. Fig. 21-22, p. 581

  20. Exporting Hazardous Waste • Basel Convention on Hazardous Waste • 1995 amended version, bans export of hazardous waste from developed to developing countries

  21. Lead • Neurotoxin: nervous system impairment, lowered IQ • Phase outs: lead-based paints, 1970; leaded gasoline, 1986 • Still a problem: found in TV, computer monitors; lead paint in old houses

  22. Mercury • Neurotoxin: affects nervous system • Vaporized Hg or particulate Hg salts • Methyl mercury (food chain) • Nature --> volcanoes • Humans---> coal burning, waste burning • Carried by wind, deposited in lakes • US FDA warns:oysters, sea bass, tuna • Electrical switches, batteries, fluorescent bulb

  23. Chlorine • Persistent, bioaccumulates • Sources: plastics (PVC), solvents, paper bleaching, purify water • PVC prod + burning generates dioxins • Replacements: soap + water, citrus based solvents; ozone, hydrogen peroxide

  24. Dioxins • Family of 75 different chlorinated hydrocarbon cmpds • Low doses of dioxins can disrupt reproductive and immune systems

  25. RCRA • Resource Conservation and Recovery Act, 1976, amended in 1984 • Requires EPA to identify hazardous waste and set standards for management by states • Firms with more than 220 lbs need permit stating how waste is managed • Permit holders use “cradle to grave” system

  26. Fig. 21-26, p. 583

  27. Fig. 21-26, p. 583

  28. Superfund Act • Comprehensive Environmental Response, Compensation, and Liability Act, 1980 • National Priorities List • Polluter pays principle • Joint and several liability • 1300 sites cleaned up, average $20 million per site

  29. Brownfields • Abandoned industrial and commercial sites, usually contaminated (factories, gas stations, etc) • 450,000-600,000 in US, 40k redeveloped • Clean up efforts are hampered by fear of liability • Congress and many states have passed laws limiting liability of lenders and developers

  30. Food scraps 12.4% Yard trimmings 12.9% Other 3.3% Wood 5.5% Rubber, leather and textiles 7.3% Paper 33.9% Plastics 11.7% Metals 7.6% Glass 5.3% p. 587

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