Upload
others
View
0
Download
0
Embed Size (px)
Citation preview
Chapter 22 Lecture.notebook February 09, 2016
Central Case: Transforming New York’s Fresh Kills Landfill• The largest landfill in the world closed in 2001
• Staten Island residents viewed the landfill as a civic blemish
• 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 worldclass public park
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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 will always be some waste left to dispose of
Chapter 22 Lecture.notebook February 09, 2016
Waste generation varies from place to place• Municipal solid waste is also called “trash” or “garbage”
• 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 goods, we generate more waste
U.S. citizens generate 1 ton/person each year
Chapter 22 Lecture.notebook February 09, 2016
The U.S. municipal solid waste stream
Chapter 22 Lecture.notebook February 09, 2016
U.S. waste generation is rising
• Since 1960, waste generation increased 2.8 times
• Per capita waste generation increased 67%
Especially plastics
Chapter 22 Lecture.notebook February 09, 2016
Developing nations are producing waste• Consumption is greatly increasing in developing nations
Rising standard of living, more packaging, poorquality goods
• Wealthy consumers often discard items that can still be used
Poor people support themselves by selling items they scavenge
from dumps
Chapter 22 Lecture.notebook February 09, 2016
Disposal methods have improved• People dumped their garbage wherever it suited them
Open 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
Chapter 22 Lecture.notebook February 09, 2016
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 pests
Closed landfills must be capped and maintained
Chapter 22 Lecture.notebook February 09, 2016
A typical sanitary landfill
To protect against environmental contamination, landfills must be located away from wetlands and earthquakeprone faults, and be 20
ft above the water table
• Leachate = liquid from trash dissolved by rainwater
It is collected and treated in landfills
But it can escape if the liner is punctured
http://www.youtube.com/watch?v=xZEdgdydZR4
http://www.youtube.com/watch?v=xZEdgdydZR4
Chapter 22 Lecture.notebook February 09, 2016
Landfills have drawbacks• Waste doesn’t decay much
40yearold newspapers can still be read
• The notinmybackyard (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 medicalwastecontaminated load
After a 6,000 mile journey it returned to New York where the waste was incinerated
Chapter 22 Lecture.notebook February 09, 2016
Landfills can be transformed after closure• Thousands of landfills lie abandoned
Smaller landfills were closed
• 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.
Chapter 22 Lecture.notebook February 09, 2016
Incinerating trash reduces landfill pressure• Incineration = a controlled process that burns garbage at very high temperatures
• Incineration in specially constructed faculties can be an improvement over openair burning of trash
But the remaining ash must be disposed of in a hazardous waste landfill
Hazardous chemicals are created and released
• Scrubbers = chemically treat the gases produced in combustion
Remove hazardous parts and neutralize acidic gaseshttp://www.theguardian.com/environment/2013/jun/14/norwaywasteenergy
http://www.theguardian.com/environment/2013/jun/14/norway-waste-energy
Chapter 22 Lecture.notebook February 09, 2016
A typical solid waste incinerator
• Baghouse = a system of huge filters that physically removes particulate matter
Chapter 22 Lecture.notebook February 09, 2016
Many incinerators create energy• Incineration reduces the volume of waste and can generate electricity
• Wastetoenergy (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
Longterm commitments interfere with the communities’ efforts to reduce and recycle waste
Chapter 22 Lecture.notebook February 09, 2016
Landfills can produce gas for energy• Bacteria decompose waste in a landfill’s oxygendeficient 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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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
• Companies maximize sales by producing shortlived goods
Increasing the longevity of goods also reduces waste
Chapter 22 Lecture.notebook February 09, 2016
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 doublesided copies
Use cloth napkins instead of paper ones
Chapter 22 Lecture.notebook February 09, 2016
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 highquality compost
Chapter 22 Lecture.notebook February 09, 2016
Chapter 22 Lecture.notebook February 09, 2016
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 and more pleasing gardens
Reduces the need for chemical fertilizers
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
• 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
The second and third steps of recycling
Chapter 22 Lecture.notebook February 09, 2016
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
Recycling rates vary widely in the U.S.
Chapter 22 Lecture.notebook February 09, 2016
Growth in recycling results from:• Municipalities’ desire to reduce waste
• The public’s satisfaction in recycling
• Recycling may not be profitable
It is expensive to collect, sort, and process materials
Plus, the more material that is recycled, the lower the price
• But market forces do not take into account the health and environmental effects of not recycling
There are enormous energy and material savings
Chapter 22 Lecture.notebook February 09, 2016
We can recycle materials from landfills• Businesses are weighing the benefits of salvaging materials in landfills that can be recycled
Metals (steel, copper)
Organic waste for compost
Harvesting methane leaking from open dumps in Asia and Africa
• These approaches work when market prices are high
But costs and regulatory requirements have made investing in landfill mining risky
Chapter 22 Lecture.notebook February 09, 2016
Financial incentives can address waste• “Payasyouthrow” 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 groceries fight them
Chapter 22 Lecture.notebook February 09, 2016
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 stateoftheart MRF handles 30,000–40,000 tons of waste annually
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
• U.S. industries generate 7.6 billion tons of waste/year
97% is wastewater
• Industrial solid waste = is not municipal or hazardous waste
• The federal government regulates municipal waste
• State or local governments regulate industrial solid waste
With federal guidanceWaste from factories, mining,
agriculture, petroleum extraction, etc.
Industrial solid waste
Chapter 22 Lecture.notebook February 09, 2016
Regulation and economics influence industrial waste generation
• Most methods and strategies of waste disposal, reduction, and recycling are similar to municipal solid waste
• State and local regulations are less strict than federal rules
• Industries may not be required to have permits or install liners or leachate collection systems
Or even monitor groundwater for contamination
It may be cheaper to generate waste than to avoid it
Industries are awarded for economic, not physical, efficiency
So they don’t have incentives to decrease waste
Chapter 22 Lecture.notebook February 09, 2016
Industrial ecology• Industrial ecology = redesigning industrial systems to reduce resource inputs while maximizing physical and economic efficiency
Industrial systems should function like ecological systems, with little waste
• Life cycle analysis = examines the life cycle of a product to make the process more ecologically efficient
Waste products can be used as raw materials
Eliminates harmful products and materials
Creates durable, recyclable, or reusable products
Chapter 22 Lecture.notebook February 09, 2016
Businesses are adopting industrial ecology• Businesses are saving money while reducing waste
• American Airlines switched from hazardous to nonhazardous materials in its Chicago facility
Decreased its need to secure permits from the EPA
It used 50,000 reusable plastic containers to ship goods, reducing packaging waste by 90%
It recycled enough aluminum cans and white paper in 5 years to save $205,000
15 ideas from employees saved over $8 million in 1 year
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
Hazardous wastes have diverse sources• Industry produces the largest amount of hazardous waste
But 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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
“Ewaste” is growing• Electronic waste (“ewaste”) = 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!
Chapter 22 Lecture.notebook February 09, 2016
Before disposing of hazardous waste• Hazardous waste used to be discarded without special treatment
• People did not know it was harmful to human health
• They assumed the substances would disappear or be diluted
• Since the 1980s, cities have designated sites or collection days to gather household hazardous waste
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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.
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
Deepwell injection• Deepwell injection = a well is drilled deep beneath the water table
Waste is injected into it
• A longterm disposal method
The well is isolated from groundwater and humans
• However, the wells can corrode and leak waste
Chapter 22 Lecture.notebook February 09, 2016
Radioactive waste is especially hazardous• 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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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
Chapter 22 Lecture.notebook February 09, 2016
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 sitebysite basis as funds are available
• The EPA must hold public hearings to inform area residents of its findings and to receive feedback
Chapter 22 Lecture.notebook February 09, 2016
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 an average of $25 million and takes 12–15 years
Chapter 22 Lecture.notebook February 09, 2016
Conclusion• Societies have made great strides in addressing our waste
problems
• Modern methods of waste management are far safer for people
and gentler on the environment
• Recycling and composting are growing rapidly
• Our prodigious consumption has created more waste than ever
before
• The best solution to our waste problem is to reduce generation
of waste
Page 1: Feb 11-2:03 PMPage 2: Feb 11-2:03 PMPage 3: Feb 11-2:03 PMPage 4: Feb 11-2:03 PMPage 5: Feb 11-2:03 PMPage 6: Feb 11-2:03 PMPage 7: Feb 11-2:03 PMPage 8: Feb 11-2:03 PMPage 9: Feb 11-2:03 PMPage 10: Feb 11-2:03 PMPage 11: Feb 11-2:03 PMPage 12: Feb 11-2:03 PMPage 13: Feb 11-2:03 PMPage 14: Feb 11-2:03 PMPage 15: Feb 11-2:03 PMPage 16: Feb 11-2:03 PMPage 17: Feb 11-2:03 PMPage 18: Feb 11-2:03 PMPage 19: Feb 11-2:03 PMPage 20: Feb 11-2:03 PMPage 21: Feb 11-2:03 PMPage 22: Mar 3-7:11 AMPage 23: Feb 11-2:03 PMPage 24: Feb 11-2:03 PMPage 25: Feb 11-2:03 PMPage 26: Feb 11-6:38 PMPage 27: Feb 11-2:03 PMPage 28: Feb 11-2:03 PMPage 29: Feb 11-2:03 PMPage 30: Feb 11-2:03 PMPage 31: Feb 11-2:03 PMPage 32: Feb 11-2:03 PMPage 33: Feb 11-2:03 PMPage 34: Feb 11-2:03 PMPage 35: Feb 11-2:03 PMPage 36: Feb 11-2:03 PMPage 37: Feb 11-2:03 PMPage 38: Feb 11-2:03 PMPage 39: Feb 11-2:03 PMPage 40: Feb 11-2:03 PMPage 41: Feb 11-2:03 PMPage 42: Feb 11-2:03 PMPage 43: Feb 11-2:03 PMPage 44: Feb 11-2:03 PMPage 45: Feb 11-2:03 PMPage 46: Feb 11-2:03 PMPage 47: Feb 11-2:03 PMPage 48: Feb 11-2:03 PMPage 49: Feb 11-2:03 PMPage 50: Feb 11-2:03 PMPage 51: Feb 11-2:03 PMPage 52: Feb 11-2:03 PMPage 53: Feb 11-2:03 PMPage 54: Feb 11-2:03 PM