1 / 34

Solid Wastes

Solid Wastes. I. Approaches to waste management. A. Waste = any unwanted material or substance that results from human activity or process 1. Municipal solid waste = non-liquid waste that comes from homes, institutions, and small businesses

jabir
Download Presentation

Solid Wastes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Solid Wastes

  2. I. Approaches to waste management A. Waste = any unwanted material or substance that results from human activity or process 1. Municipal solid waste =non-liquid waste that comes from homes, institutions, and small businesses 2. Industrial solid waste = waste from production of consumer goods, mining, agriculture, and petroleum extraction and refining. ABOUT 98.5% OF ALL SOLID WASTE IN THE U.S. IS FROM INDUSTRIAL SOLID WASTE (mining 76%). 3. Hazardous waste =solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive

  3. I. Approaches to waste management B. Three main components of waste management: 1) Minimizing the amount of waste we generate (source reduction) 2) Recovering waste materials and finding ways to recycle them 3) Disposing of waste safely and effectively C. Source reduction is the preferred approach

  4. I. Approaches to waste management D. Waste stream = flow of waste as it moves from its sources toward disposal destinations • More efficient use of materials, consume less, buy goods with less packaging, reusing goods E. Recovery (recycling, composting) = next best strategy in waste management 1) Recycling = sends used goods to manufacture new goods 2) Composting = recovery of organic waste

  5. F. Patterns in the municipal solid waste stream vary 1) In the U.S., paper, yard debris, food scraps, and plastics are the principal components of municipal solid waste • Even after recycling, paper is the largest component of solid waste • Most waste comes from packaging 2) In developing countries, food scraps are the primary contributor • Wealthy nations invest more in waste collection and disposal

  6. G. The U.S. municipal solid waste stream

  7. H. Waste generation is rising in all nations 1) Consumption is greatly increasing in developing nations • Rising material standard of living and more packaging • 2) Wealthy consumers often discard items that can still be used • At many dumps and landfills in the developing world, poor people support themselves by selling items they scavenge

  8. II. Integrated Waste Management • Integrated waste management (IWM) is a variety of strategies for both waste reduction and waste management. Scientists call for a much greater emphasis on waste reduction. Some scientists and economists have estimated that 75-90% of municipal wastes generated could be eliminated by a combination of IWM strategies.

  9. I = I don’t need it! Use less, source reduction W = What, that’s not trash! Recycle M = Make it disappear. Disposal

  10. II. Integrated Waste Management B. First IWM Priority: Source Reduction = preventing waste generation in the first place 1) Change industrial process to elimanate use of harmful chemicals or pollutants 2) Reduce packaging and materials in products. Packaging number one generator of municipal/industrial solid wastes! 3) Make products that last longer and are recyclable, reusable, or easy to repair.

  11. II. IWM C. Why source reduction is good for businesses: 1. Avoids costs of disposal and recycling 2. Helps conserve resources 3. Minimizes pollution 4. Can save consumers and businesses money

  12. II. IWM D. How people can practice source reduction: • Buy less stuff • Buy groceries/items in bulk • Rent or borrow items instead of buying them • Try to reduce packaging use – cloth grocery bags, cups for coffee

  13. III. Recycling A. Second IWM Priority: Prevent items from being thrown away • Reuse • Repair • Recycle • Compost • Buy Reusable and recyclable products

  14. III. Recycling B. Recycling = collecting materials that can be broken down and reprocessed to manufacture new items 1. Recycling diverts 58 million tons of materials away from incinerators and landfills each year C. Step 1 in the recycling loop is collection and processing of recyclable materials through curbside recycling or designated locations • Materials recovery facilities (MRFs) = workers and machines sort items, then clean, shred and prepare them for reprocessing

  15. D. Single Stream Recycling – Putting all recyclables in a bin together. No need to sort. E. General Recycling Rules in Austin: • Wash out your food containers/cans first! • Plastics #1-7 (Includes plastic utensils, take-out containers, medicine bottles, plastic lids from bottles) • Glass, aluminum, “tin” cans, metal lids from glass jars • Paper: junk mail, cards, wrapping paper, manila folders, boxboard cardboard. Any boxboard with food residue cannot be recycled

  16. F. What CAN’T go in the single-stream recycling: 1. Unrecyclable Plastics: - Plastic bags/plastic food cling-wrap or packaging - Styrofoam 2. Unrecyclable Glass • Broken glass • Light bulbs

  17. 3. Unrecyclable Metal • Aluminum foil • Coat hangers/scrap metal (nails, etc.) 4. Unrecyclable paper • Disposable paper plates and cups • Milk/juice cartons • Gift bags

  18. III. Recycling G. Step 2 is using recyclables to produce new products 1. Many products use recycled materials H. In step 3, consumers purchase goods made from recycled materials 1. Must occur if recycling is to function 2. As markets expand, prices will fall

  19. I. Recycling has grown rapidly and can expand 1. The EPA calls the growth of recycling “one of the best environmental success stories of the late 20th century” 2. Recycling rates vary widely, depending on the product • 99% of car batteries • 67% of major appliances are recycled • Only 6% of plastics are recycled

  20. J. Growth in recycling results from: 1. A desire in municipalities to reduce waste output 2. The public’s desire to expand recycling 3. New technologies and markets make recycling more and more cost effective 4. Recycling is often not financially profitable because it is expensive to collect, sort and process recycled materials 5. However, market forces do not take into account the health and environmental effects of not recycling • Enormous energy and material savings through recycling

  21. Recycling rates vary widely in the U.S.

  22. K. Composting = the conversion of organic waste into mulch or humus through natural biological processes of decomposition L. Home composting: 1. Householders place waste into composting piles, underground pits, or specially constructed containers 2. As waste is added, the heat from microbial action builds in the interior and decomposition proceeds 3. Earthworms, bacteria, soil mite, sow bugs, and other organisms convert waste into high-quality compost

  23. M. Municipal composting programs: Divert food and yard waste from the waste stream to central composting facilities • Reduces landfill waste • Diverts all yard clippings • Reduces the need for chemical fertilizers • Makes healthier plants and more pleasing gardens

  24. IV. Disposal methods A. Last Priority: Waste management • Treat waste to reduce toxicity • Incinerate waste • Bury waste in landfills • Release waste into environment for disposal or dilution

  25. IV. Disposal methods B. Historically people dumped their garbage wherever it suited them 1. Open dumping and burning still occur throughout the world C. Most industrialized nations now bury waste in lined and covered landfills or burn it in incineration facilities • In the U.S., recycling is decreasing pressure on landfills

  26. IV. Disposal methods D. Sanitary landfills = waste buried in the ground or piled in large, engineered mounds 1. Must meet national standards set by the EPA under the Resource Conservation and Recovery Act (RCRA) of 1976 2. Waste is partially decomposed by bacteria and compresses under its own weight to make more space 3. Layered with soil to reduce odor, speed decomposition, reduce infestation by pets 4. When a landfill is closed, it must be capped and maintained

  27. A typical sanitary landfill E. To protect against environmental contamination, landfills must be located away from wetlands, earthquake-prone faults, and 20 ft above water table

  28. F. Landfills can be transformed after closure 1. Thousands of landfills lie abandoned • Managers closed smaller landfills and made fewer larger landfills 2. In 1988, the U.S. had nearly 8,000 landfills • Today there are fewer than 1,700 3. Growing cities converted closed landfills into public parks • Flushing Meadows in Queens, New York, was redeveloped for the 1939 World’s Fair

  29. G. Landfills have drawbacks 1. Experts believe that leachate will eventually escape • The liner will become punctured • Leachate collection systems eventually aren’t maintained 2. It is hard to find places suitable for landfills • The Not-In-My-Backyard (NIMBY) syndrome 3. The “Garbage barge” case • In 1987, Islip, New York’s landfills were full, and a barge traveled to empty the waste in North Carolina, which rejected the load • It returned to Queens to incinerate the waste, after a 9,700 km (6,000 mile) journey

  30. H. Incineration = a controlled process in which mixed garbage is burned at very high temperatures I. Incineration in specially constructed faculties can be an improvement over open-air burning of trash 1. But, the remaining ash must be disposed of in a hazardous waste landfill 2. Hazardous chemicals are created and released during burning J. Scrubbers = chemically treat the gases produced in combustion to remove hazardous components and neutralize acidic gases (also used on coal plants to remove sulfur compounds).

  31. A typical solid waste incinerator

  32. K. Incineration is used to reduce the volume of waste and generate electricity L. Waste-to-energy facilities (WTE) = use the heat produced by waste combustion to create electricity 1. More than 100 facilities are in use across the U.S. 2. They can process nearly 100,000 tons of waste per day 3. But, they take many years to become profitable M. Companies contract with communities to guarantee a minimum amount of garbage 1. Long-term commitments interfere with the communities’ later efforts to reduce waste

  33. N. Landfills can produce gas for energy 1. Bacteria can decompose waste in an oxygen-deficient environment 2. Landfill gas = a mix of gases that consists of roughly half methane • Can be collected, processed, and used like natural gas • When not used commercially, landfill gas is burned off in flares to reduce odors and greenhouse emissions

More Related