6a582a3a0c939ddcabb9917b059954c8.ppt
- Количество слайдов: 68
UNIT 3: Waste Management 5/1/07 Solid waste disposal
Side note: Review Envi. Law (Ch. 18) • National Environmental Policy Act (NEPA) (1969) • Water law • Pollution control: – Clean Water Act (1977) – Clean Air Act (1963) • Waste Disposal – Solid Waste Disposal Act (1965) – Resources Conservation and Recovery Act (RCRA) (1976) – CERCLA (1980)
Old approach to solid waste • The dump
The local dump: Mission Bay “Landfill” l. Operated from 1952 to 1959 l. Records on dumping destroyed in 1959 when closed l. City denied existence till 1987 l. Ramada Hotels study – 68 toxic substances found in soil sample –Heavy metals, plating solutions, cyanide, arsenic, hydrogen sulfide, methane l. Existence preventing further building, development, and landscaping of bay front property l. Uncapped and uncontained –Mission Bay dredge spoils used for coverage
Mission Bay Landfill l Potentially top 20 CERCLA site Waste in 55 gallon drums with 15 year life expectancy Health and environmental concerns – l l Hydrogen sulfide levels at Sea World ride Mission Bay recreational area San Diego River wetland area
Recent Investigation l 2002 Councilwoman Donna Frye convenes Mission Bay Technical Advisory Committee – l l Members from consulting, academia, citizens Develop two phase study at cost of $600, 000 initiated in 2002 SCS Engineers conducted study; completed in 2006 http: //www. sandiego. gov/citycouncil/c d 6/crtk/mblandfill. shtml
Sanitary Landfill • Refuse is deposited, compacted, and covered • Potential hazards: – Leachate: mineralized liquid • Concentration of pollutants much higher than raw sewage or slaughterhouse waste – Methane gas • May be trapped and used for energy generation
Closed sanitary landfill
“State of the art” landfill with a double liner of clay and plastic, a leachate collection system, and groundwater and vadose zone monitoring wells Map view Cross section
Site selection for sanitary landfills • Avoid: – – siteing over aquifers swampy areas Floodplains High water table • Seek: – Siteing over rocks of low hydraulic conductivity (clays & silts) – Flat areas
Monitoring sanitary landfills • Monitoring wells to monitor groundwater • Monitoring wells to monitor vadose zone • Test soils – Gases – Heavy metals • Test crops and plants in the disposal area • Test surface water runoff
San Diego Landfills & issues Miramar Landfill http: //www. sandiego. gov/environm ental-services/ems/index. shtml
Hazardous Chemical and Radioactive Waste Management Don’t put down the drain or in the landfill
Hazardous Chemical and Radioactive Waste Management Don’t put down the drain or in the landfill
Hazardous Waste – Toxic to humans and other living things – ignite or explode – corrosive – Unstable – 150 million metric tons (excluding radioactive waste) generated in the U. S. per year
Examples of hazardous waste • Organic compounds • Organic solvents and residues • Heavy metals • Oil • Pigments • • • Acids Cyanides Dyes Ammonia salts Radioactive waste
Hazardous wastes may be produced in the manufacture of: • • plastics pesticides medicines paints • petroleum products • metals • leather • textiles
Regulations • 1976: Resource Conservation and Recovery Act (RCRA) – Stringent record keeping and reporting to track “cradle to grave” control of hazardous waste
1980: Comprehensive Environmental Response Compensation and Liability Act (CERCLA) • Established a revolving fund (“superfund”) to clean up the worst abandoned hazardous waste sites – “EPA National Priorities List”
Envi Impacts at Superfund Priorities Sites
Cost of Superfund • taxes on oil and some products that generate hazardous wastes • 1980: $1. 6 billion • 1986: $ 8. 5 billion • 1990: $ 11. 5 billion – Average cost to clean up a SINGLE SITE: • $30 million (not counting litigation) • By 1995: 40, 000 sites.
Hazardous waste disposal Hazardous Chemical Wastes: 1) Secure landfill 2) Deep well 3) Other: • Incineration • Neutralized by chemical treatment Radioactive Wastes
Radioactive waste • Differ from other hazardous chemical wastes – Half life: • • Uranium-238: T 1/2 : 4. 5 billion yrs Plutonium-239: T 1/2 : 24, 000 yrs. Strontium-90: T 1/2 : 29 yrs Iodine-131: T 1/2 : 8 days – Type of radiation emitted
Classification of Radioactive Wastes • Low level – Over 90% – States dispose of their own • High level – Spent reactor fuel rods – Currently contained in temporary disposal sites – 1985: EPA specified that they should be disposed so they cause fewer than 1000 deaths in 10, 000 years
How Much Nuclear Waste is in the United States? 49, 000 metric tons of spent nuclear fuel from nuclear reactors. 22, 000 canisters of solid defense-related radioactive waste
Where is radioactive waste kept • temporary facilities at some 125 sites in 39 states. • more than 161 million people reside within 75 miles of temporarily stored nuclear waste.
Treating radioactive waste Leaving it where it is • 2. Disposing of it in various ways • 1. ◦ Sub-seabed disposal ◦Very deep-hole disposal ◦ Space disposal ◦ Ice-sheet disposal ◦ Island geologic disposal ◦ Deep-well injection disposal • 3. Making it safer through advanced technologies
Nuclear Waste Policy Act (1982) • established a comprehensive national program for the safe, permanent disposal of highly radioactive waste • directed the U. S. Department of Energy to study suitable sites for a geologic repository • the Nuclear Regulatory Commission & the Department of Energy is to build and operate it – in 2002, Congress and the President approved the development of a geologic repository at Yucca Mountain, Nevada.
Selecting a site for permanent high-level radioactive disposal: • Issues: – Sites with LONG TERM geologic stability – Social/Political issues – Arid climate – Low regional water table – Low population density – Appropriate rock and geologic structure – Engineering technology for containment
Two sites were in development in U. S. • Waste Isolation Pilot Plant (WIPP) – Carlsbad, New Mexico – Store waste drums in rooms in underground salt deposit • Yucca Mountain, Nevada*** – 1987: Congress designated as the only site for study – Storage in volcanic tuff
Yucca Mountain Project http: //www. ocrwm. doe. gov/ymp/index. shtml • Over 20 years of study • 4 billion dollars • February 15, 2002: President Bush recommended to Congress the issuance of a construction permit for the site
Most Popular Reasons To Oppose Yucca Mountain Project • 1. Accomplishes No Reasonable Objective. – Not enough space to store all of the waste • 2. Provides Minimal Protection. – The casks provide the protection. So why Yuca Mtn? • 3. Creates More Nuclear Waste. – Facilities have a storage limit. By decreasing the storage on-site, additional waste will be generated. • 4. Adverse Effects on Future Generations. – Average half life of over 200, 000 years. • 5. Earthquake Danger. – Third most seismically active area in US.
Opposition to Yucca Mnt. (Cont. ) • 6. Fifty Million People Endangered. – Routes will move through 734 counties across the United States. The high-level radioactive waste contained in the casks will endanger 50 million innocent people who live within 3 miles of the proposed shipment routes. • 7. Terrorist Attacks. • 8. Costly Accidents and Limited Liability. – For each spill that may occur (one out of every 300 shipments is expected to have an accident) the cost of the clean-up is estimated conservatively at $6 billion dollars. Paid by taxpayer money.
Continued • 9. Adverse Impact on Water Sources. – Yucca Mountain sits above the only source of drinking water for the residents of Amargosa Valley. • 10. Violates Treaties. – Yucca Mountain is located on Native American land, belonging to the Western Shoshone by the treaty of Ruby Valley. The Western Shoshone National Council has declared this land a nuclear free zone and demanded an end to nuclear testing and the dumping of nuclear wastes on their land.
Alternate Disposal Methods • MOX fuel burning – mixing plutonium with uranium. Burns up the plutonium by nuclear fission • Vitrification – borosilicate glass logs buried in deep (over 3 km) boreholes • Subductive Waste Disposal