waste n.
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leigh-mullen

Waste - PowerPoint PPT Presentation

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  1. Waste

  2. Central Case: Transforming New York’s Fresh Kills Landfill • The largest landfill in the world closed in 2001 • It was briefly reopened to bury rubble from the World Trade Center after the 9/11/2001 attack • It will take 30 years to turn it into a public park

  3. Approaches to waste management • Waste= any unwanted material or substance that results from human activity or process • Municipal solid waste = nonliquid waste from homes, institutions, and small businesses • Industrial solid waste = from production of goods, mining, agriculture, petroleum extraction and refining • Hazardous waste = solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive • Wastewater=used in a household, business, or industry • Also, polluted runoff from streets and storm drains

  4. Aims in managing waste • Waste management aims to: • Minimize the amount of waste generated (source reduction) • Recover waste materials and recycle them • Dispose of waste safely and effectively • Source reduction is the preferred approach

  5. Reducing waste entering the waste stream • Waste stream= the flow of waste as it moves from its sources toward disposal destinations • Use materials efficiently, consume less, buy goods with less packaging, use goods longer • Recovery (recycling, composting) =next best strategy in waste management • Recycling = sends used goods to facilities to manufacture into new goods (e.g., newspaper) • Composting = recovery of organic waste • But there is always some waste left

  6. Waste generation varies from place to place • In the U.S., paper, yard debris, food scraps, and plastics are the principal components of municipal solid waste • Even after recycling, most solid waste is paper • In developing countries, food scraps are the primary contributor • Most municipal solid waste comes from packaging and nondurable goods (discarded after a short time of use) • As we get more stuff, we generate more waste • U.S. citizens generate 1 ton/person each year

  7. The U.S. municipal solid waste stream

  8. U.S. waste generation is rising • Since 1960, waste generation increased 2.8 times • Per capita waste generation increased 67% • Especially plastics

  9. Disposal methods have improved • People used to dump garbage wherever they wanted • Dumping and burning still occur • Most industrialized nations bury waste in lined and covered landfills or burn it in incineration facilities • In the U.S., recycling is decreasing pressure on landfills • In the U.S., recycling is decreasing pressure on landfills

  10. Sanitary landfills are regulated • Sanitary landfills= waste buried in the ground or piled in large, engineered mounds to prevent contamination and health threats • U.S. landfills must meet the EPA’s national standards • Under the Resource Conservation and Recovery Act (RCRA) of 1976 • Waste is partly decomposed by bacteria and compresses under its own weight to make more space • Soil layers reduce odor, speed decomposition, reduce infestation by pets • Closed landfills must be capped and maintained

  11. A typical sanitary landfill • Leachate = liquid from trash dissolved by rainwater • It is collected and treated in landfills • But it can escape if the liner is punctured To protect against environmental contamination, landfills must be located away from wetlands and earthquake-prone faults, and be 20 ft above the water table

  12. Landfills have drawbacks • Waste doesn’t decay much • 40-year-old newspapers! • The not-in-my-backyard (NIMBY) syndrome • The “garbage barge” case in Islip, New York in 1987 • Full landfills forced a barge to take the waste to North Carolina, Louisiana, and Mexico • All rejected the medical-waste-contaminated load • After a 6,000 mile journey it returned to New York where the waste was incinerated

  13. Landfills can be transformed after closure • Thousands of landfills lie abandoned • In 1988, the U.S. had 8,000 landfills • Today there are less than 1,800 • Cities have converted closed landfills into public parks • Once properly capped, old landfills can serve other • purposes such as the Cesar Chavez Park in Berkeley, California.

  14. A typical solid waste incinerator • Baghouse = a system of huge filters that physically removes particulate matter

  15. Many incinerators create energy • Incineration reduces the volume of waste and can generate electricity • Waste-to-energy (WTE) facilities= use the heat produced by waste combustion to create electricity • Over 100 facilities are in use across the U.S. • They process nearly 100,000 tons of waste per day • But they take many years to become profitable • Companies contract with communities to guarantee a minimum amount of garbage • Long-term commitments interfere with the communities’ efforts to reduce and recycle waste

  16. Landfills can produce gas for energy • Bacteria decompose waste in a landfill’s oxygen-deficient environment • Landfill gas = a mix of gases that consists of 50% methane • Can be collected, processed, and used like natural gas • At Fresh Kills, the city sells the gas for $11 million/year • When not used commercially, landfill gas is burned off to reduce odors and greenhouse emissions

  17. Reducing waste is a better option • Source reduction= preventing waste in the first place • Avoids costs of disposal and recycling • Helps conserve resources • Minimizes pollution • Can save consumers and businesses money • Most waste consists of materials used to package goods • Use minimal packaging • Use recyclable packaging • Reduce the size or weight of goods and materials

  18. Governments fight waste and litter • Some government address a major source of litter and waste: plastic grocery bags • Grocery bags can take centuries to decompose • They choke and entangle wildlife and cause litter • 100 billion of them are discarded each year in the U.S. • Many governments have banned nonbiodegradable bags

  19. Planned obsolescence • Companies maximize sales by producing short-lived goods • Increasing the longevity of goods also reduces waste so if consumers demand goods that last longer, manufacturers will respond.

  20. Reuse is a main strategy to reduce waste • Items can be used again • Use durable goods used instead of disposable ones • Donate items to resale centers (Goodwill and the Salvation Army) • Other actions include: • Rent or borrow items instead of buying them • Bring your own cup to coffee shops • Buy rechargeable batteries • Make double-sided copies • Use cloth napkins instead of paper ones

  21. Composting recovers organic waste • Composting = the conversion of organic waste into mulch or humus through natural decomposition • It can be used to enrich soil • Home composting: • Householders place waste into composting piles, underground pits, or specially constructed containers • Heat from microbial action builds up and decomposition proceeds • Earthworms, bacteria, and other organisms convert waste into high-quality compost

  22. Municipal composting programs • These programs divert food and yard waste from the waste stream to central composting facilities • The resulting mulch can be used for gardens and landscaping • Half of U.S. states now ban yard wastes from the municipal waste stream • Accelerating the move to composting • Municipal composting reduces landfill waste • Enriches soil and encourages soil biodiversity • Makes healthier plants • Reduces the need for chemical fertilizers

  23. Recycling consists of three steps • Recycling = collecting materials that can be broken down and reprocessed to manufacture new items • Recycling diverted 61 million tons of materials away from U.S. incinerators and landfills in 2008 • Step 1 = collection and processing of recyclable materials through curbside recycling or designated locations • Materials recovery facilities (MRFs) = workers and machines sort, clean, shred, and prepare items

  24. The second and third steps of recycling • Step 2 = using recyclables to produce new goods • Many products use recycled materials • Step 3 = consumers buy goods made from recycled materials • Must occur if recycling is to function • As markets expand, prices will fall

  25. Recycling has grown rapidly and can expand • The growth of recycling is “One of the best environmental success stories ….” • U.S. recycling rates vary • Depending on the product and state • Greenhouse gas emissions equal to 10 billion gallons of gas are prevented each year The U.S. recycles 24.4% of its waste stream

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

  27. Financial incentives can address waste • “Pay-as-you-throw” approach = uses financial incentives to influence consumer behavior • The less waste a house generates, the less it is charged for trash collection • Bottle bills = consumers receive a refund for returning used bottles • They are profoundly successful • But beverage industries and grocery stores fight them

  28. A Canadian city showcases reduction and recycling • Edmonton, Alberta has one of the most advanced waste management programs • Waste: 40% is landfilled, 15% is recycled, 45% is composted • 90% of the people participate in curbside recycling • It produces 80,000 tons/year in its composting plant • Its state-of-the-art facility handles 30,000–40,000 tons of waste annually

  29. Edmonton, Alberta’s waste management • Waste is dumped in the composting plant • The plant is the size of eight football fields • Each year the plant produces: • 80,000 tons of compost • Gas to power 4,600 home • Thousands of dollars for the city

  30. An example of industrial ecology Interface, a carpet tile company, cut its waste 80%, fossil fuel use 45%, and water use 70% while saving $30 million/year and raising profits 49%

  31. Conventional Waste Managment in Fiji MushroomGrowing Chicken Raising Methane Gas Production Fish Ponds Brewery waste dumped into oceans to destroy coral reefs Brewery Muck dumped on fields Waste piles up Methane vented Muck cleaned out

  32. Industrial Ecology in Fiji MushroomGrowing Chicken Raising Methane Gas Production Fish Ponds HydroponicGardening Brewery waste fertilizes mushrooms Brewery Mushroom residue feeds chickens Chicken waste is composted Solids become fish food Nutrients used in gardens

  33. Defining hazardous waste • Hazardous waste is a liquid, solid, or gas and is one of the following: • Ignitable = easily catches fire (natural gas, alcohol) • Corrosive = corrodes metals in storage tanks or equipment • Reactive= chemically unstable and readily reacts with other compounds, often explosively or by producing noxious fumes • Toxic = harms human health when inhaled, ingested, or contact human skin

  34. Hazardous wastes have diverse sources • Industry produces the largest amount of hazardous waste • Waste generation and disposal are highly regulated • Households = the largest source of unregulated hazardous waste • Paint, batteries, solvents, cleaners, pesticides, etc. • Mining, small businesses, agriculture, utilities, and building demolition all produce hazardous wastes • Organic compounds and heavy metals are particularly hazardous because their toxicity persists over time

  35. Organic compounds can be hazardous • Synthetic organic compounds resist bacterial, fungal, and insect activity • Plastics, tires, pesticides, solvents, wood preservatives • Keep buildings from decaying, kill pests, and keep stored goods intact • Their resistance to decay makes them persistent pollutants • They are toxic because they are readily absorbed through the skin • They can act as mutagens, carcinogens, teratogens, and endocrine disruptors

  36. Heavy metals can be hazardous • Lead, chromium, mercury, arsenic, cadmium, tin, and copper • Used widely in industry for wiring, electronics, metal plating and fabrication, pigments, and dyes • They enter the environment when they are disposed of improperly • Heavy metals that are fat soluble and break down slowly can bioaccumulate and biomagnify

  37. “E-waste” is growing • Electronic waste (“e-waste”) = waste involving electronic devices • Computers, printers, cell phones, TVs, MP3 players • Americans discard 400 million devices/year • 67% are still in working order • They are put in landfills, but should be treated as hazardous waste • Valuable trace minerals can be recovered – the 2010 Olympic medals were made from e-waste!

  38. http://www.ban.org/- Find a responsible recycler!

  39. RCRA • Resource Conservation and Recovery Act (RCRA) = states must manage hazardous waste • Large generators of hazardous waste must obtain permits • Materials must be tracked “from cradle to grave” • Intended to prevent illegal dumping

  40. Illegal dumping of hazardous waste • Hazardous waste disposal is costly • It results in illegal and anonymous dumping • Illegal dumping creates health risks • Along with financial headaches for dealing with it • Industrial nations illegally dump in developing nations • The Basel Convention, an international treaty, should prevent dumping, but it still happens • High costs also encourage companies to invest in reducing their hazardous waste • Incineration, bacterial and plant decomposition, etc.

  41. Three disposal methods for hazardous waste • These do not lessen the hazards of the substances • But they help keep the substance isolated from people, wildlife, and ecosystems • Landfills = must have several impervious liners and leachate removal systems • Design and construction standards are stricter than for ordinary sanitary landfills • Must be located far from aquifers

  42. Surface impoundments • Surface impoundments =store liquid hazardous waste • Shallow depressions are lined with plastic and clay • The water evaporates • The residue of solid hazardous waste is transported elsewhere • The clay layer can crack and leak waste • Rainstorms cause overflow, contaminating nearby areas

  43. Deep-well injection • Deep-well injection= a well is drilled deep beneath the water table • Waste is injected into it • A long-term disposal method • The well is isolated from groundwater and humans • However, the wells can corrode and leak waste

  44. Radioactive waste is very dangerous and persistent The U.S. has no designated single disposal site Waste will accumulate around the nation The Waste Isolation Pilot Plant (WIPP) = the first underground repository for transuranic waste from nuclear weapons development Caverns are 655 m (2,150 ft) below ground in a huge salt formation thought to be geologically stable WIPP became operational in 1999 and is receiving thousands of shipments of waste Radioactive waste is especially hazardous

  45. Contaminated sites are being cleaned up • Globally, thousands of former military and industrial sites are contaminated with hazardous waste • Dealing with these messes is difficult, time consuming, and expensive • Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (1980) • Superfund is administered by the EPA • Established a federal program to clean up U.S. sites polluted with hazardous waste

  46. Superfund • Experts identify polluted sites, take action to protect groundwater near these sites, and clean up the pollution • The EPA must clean up brownfields • Lands whose reuse or development is complicated by the presence of hazardous materials • Two events spurred creation of Superfund legislation • In Love Canal, Niagara Falls, New York, in 1978–1980, families were evacuated after buried chemicals rose to the surface • Times Beach, Missouri, was evacuated after contamination with dioxin from oil sprayed on roads

  47. The Superfund process • Once a Superfund site is identified, EPA scientists note: • How close the site is to human habitation • If wastes are currently confined or likely to spread • If the site threatens drinking water supplies • Harmful sites are placed on the National Priority List • They are ranked by their level of risk to human health • Cleanup goes on a site-by-site basis as funds are available • The EPA must hold public hearings to inform area residents of its findings and to receive feedback

  48. Who pays for cleanup? • CERCLA operates under the polluter pays principle = charge polluting parties for cleanup • However, the responsible parties often can’t be found • A trust fund was established by a federal tax on petroleum and chemical industries • The fund is bankrupt and Congress has not restored it • So taxpayers now pay all costs of cleanup • Fewer cleanups are being completed • 1,279 sites remain, and only 341 have been cleaned up • Cleanup costs $25 million and takes 12–15 years