Upload
hatuong
View
220
Download
2
Embed Size (px)
Citation preview
1/15/2013
1
WASTE
THE WASTE PROBLEM
More than 30 million tons of waste are generated worldwide yearly 2 % of it is exported
Contaminated waste sites are a problem Short term profit interests, lack of regulation and weak law enforcement
promote problems ongoing Issues of environmental justice are key
Health hazards Infectious disease risks from poorly managed solid waste Contamination of drinking water and soil by biological, chemical, and
mining wastes Gas migration and leachate discharges from landfills Emissions of air pollutants from incinerators Contamination of food by waste chemicals that escape into the
environment
WHAT IS WASTE?Waste Stream: everything we throw away.
Typically divided into three broad categories:Municipal solid waste
Special waste
Hazardous waste
1/15/2013
2
SPECIAL WASTES
Medical waste Generated from health care treatment or research facilities
(human and nonhuman) Have come into contact with body fluids or other materials
that may contain infectious agents and may cause disease Mining waste
The extraction of metals, coal, and oil from the Earth’s crust The volume of wastes from mining operations exceeds the
volume of wastes from all other categories combined Regulated both by solid waste laws and regulations and by
water pollution control and land use and reuse laws and regulations
Sewage sludge
E-WASTE
Disassembly and recycling of obsolete appliances and electronics The preferred strategies are to reuse the
equipment, recycle the materials, properly dispose of the equipment in an approved landfill
Heavy metals such as mercury, lead, and cadmium cause dangerous exposure as the electronics are processed unprotected70% of heavy metal contamination (lead,
cadmium, mercury) comes from e-wasteMuch being shipped to developing world-
environmental justice issue In Europe, manufacturers have “cradle to grave”
responsibility for their products
A CHINESE WOMAN EXTRACTS VALUABLE METALS FROM E-WASTE
1/15/2013
3
WASTE MANAGEMENT STRATEGIES
LANDFILLS
Most common waste method for disposal worldwide Historically, landfills have been a convenient, inexpensive
waste-disposal option. Rising land prices and shipping fees, and demanding
construction and maintenance requirements, are increasing costs.Suitable landfill sites are become scarce
1,200 - 1,500 landfills have closedCommunities are rejecting new landfills.
Positive trend in landfills is methane recovery
WASTE DISPOSAL METHODS
Sanitary Landfills Site selection is complicated
Cost of the land, insurance of an adequate area to provide waste disposal capacity for a reasonable time period, an adequate elevation or separation to protect regional ground water, available or appropriate soil for daily soil cover requirements, and an adequate buffer from surrounding populations
Refuse compacted and covered every day with a layer of dirtDirt takes up as much as 20% of landfill spaceMany now becoming “sanitary”
.
1/15/2013
4
INCINERATION
Reduces disposal volume by 80-90% Energy Recovery - heat derived from incinerated refuse is a
useful resource• Over 1000 waste to energy plants worldwide
Problems- Expensive Residual ash usually contains toxic material (dioxins, lead, cadmium)
Types of incinerators: Refuse-Derived Fuel Mass Burn Small scale incineration- Burn in backyard barrels, open dumps, and crude incinerators
DEEP WELL INJECTION AND OPEN DUMPING
Deep well injection: A liquid waste disposal technology
Open dumping Releases hazardous material Still the predominant method of waste disposal in
developing countries Most developed countries forbid open dumping.
Estimated 200 million liters of motor oil are poured into the sewers or soak into the ground each year in the U.S.
OCEAN DUMPING
Every year 20 million tons of plastic debris are dumped at sea
Significant impact on wildlife
1/15/2013
5
SHRINKING THE WASTE STREAM- PRIMARY MANAGEMENT
RECYCLING
Reprocessing of discarded materials into new, useful productsDeveloped world-
Aluminum cans, copperDeveloping world
Old tires for road surface, newspapers for insulationMunicipal level
Compost yard waste Construction waste can be recycledGasifiers convert biomass (food-soaked paper) to
natural gas
RECYCLING Benefits of recycling
Saves money, raw materials, and landfill spaceCosts $35/ton as opposed to $80/ton to landfill
Encourages individual responsibilityReduces pressure on disposal systems Lowers demand for raw resourcesReduces energy consumption and air pollution
1/15/2013
6
REUSE AND PRODUCE LESS
Reuse Auto parts, brass fittings, woodwork, bricks, are routinely
reused Glass and plastic bottles are washed and refilled Scavenging, sorting and reprocessing scraps from dumps
Produce less Individual responsibility Reduce excess packaging Paper, plastic, glass, and metal packaging material make up
50% of domestic trash
HAZARDOUS WASTE
HAZARDOUS WASTE
Legally, hazardous waste is any discarded liquid or solid that contains substances known to be: Fatal to humans or laboratory animals in low doses Toxic, carcinogenic, mutagenic, or teratogenic to humans or
other life-forms Ignitable with a flash point less than 60o C Corrosive Explosive or highly reactive
U.S. industries alone generate 265 million metric tons of officially classified hazardous wastes annually At least 40 million metric tons of toxic and hazardous
wastes are released into the environment
1/15/2013
7
HAZARDOUS WASTE MANAGEMENT OPTIONS
Produce Less Waste
Convert to Less Hazardous Substances Physical treatment, incineration, chemical processing,
bioremediation
Store Permanently Retrievable Storage
Can be inspected and periodically retrieved if necessary Secure Landfills
Multiple liners, covered by a cap,leachate is processed and monitored
TRANSPORT OF TOXIC WASTE
Transportation of hazardous wastes to disposal sites is dangerous
RADIOACTIVE WASTE
Contains radioactive chemical elements
Two subcategories Low-level waste: used protective clothing and other items
that contain low levels of radioactivity per mass or volume High-level : spent nuclear fuel and waste materials left
after spent fuel is reprocessed
Decommissioning of old nuclear plants 60 % of Americans support nuclear energy many plants
are oldWill cost 200 billion to 1 trillion dollars for all in US
Storage is a big problem
1/15/2013
8
WASTE REGULATION
REGULATION
UN Human Rights Commission is now monitoring illicit movement and dumping of toxic waste
Some international focus and collaboration Basel Convention on Control of Trans-boundary Movement
of Hazardous Waste and Disposal (1989) Stockholm Convention on Persistent Organic Pollutants
(2001) Strategic Approach to International Chemicals Management
(2006) Control and clean up measures have potential for
building confidence and collaboration in former conflict regions
FUTURE WASTE MANAGEMENT NEEDS
Avoidance of dumping Ongoing research on cause and effect interactions
between chemicals and human health Improved technology for risk assessment International strength to enforce regulation Corporate and social responsibility Increased participation of those affected by waste
sites Education Participation in governance process