UNIT 3:Waste Management

4/26/07

Groundwater pollution and treatment

Solid waste disposal

Groundwater Pollution and Treatment

•Saltwater intrusion More than half of the world’s population lives in or

near the coastal zones GW pollution from saltwater intrusion is not a

local isolated problem Causes major water supply problems in NY, FL, CA Case History: Long Island

What is MTBE?(methyl tertiary butyl ether)

• A gas additive contaminating drinking water

History of MTBE?

• 1970 MTBE replaced lead in gasoline

• Clean Air Act of 1990 mandated MTBE in gas

• 4.5 billion gallons of MTBE have been used each year

• Discovered health risks in 1997

Health Risks of MTBE

• Dizziness

• Rashes

• Swelling

• Respiratory problems

• Diarrhea

• Caused cancer in research rats and mice

What are the concerns with MTBE?

• Soluble in water

• Degrades slowly

• Does not readily bind to soil particles

• Resists natural degradation

• travels quick and easy through ground water

Concentration of MTBE?

• For every 10 gallons of gas there is 1 gallon of MTBE

• 1 cup of MTBE contaminate a reservoir 360ft wide, 15ft deep holding 5 million gallons of water

GW Treatment

Methods of solid waste disposal

• On site disposal– Garbage disposals, small-scale incineration– Composting– Incineration– Open dumps– Sanitary landfills

Figure 12.2

Composition of Urban Solid Waste (by wt.) (Table 12.1)

0

5

10

15

20

25

30

35

40

PaperHardwastePlasticsMetals

Food Glass Wood Other

Open Dumps

• Oldest, most commonly used

• No safety

• Breeding grounds for pests

• Phased out in U.S.

• Continued use in Third World Countries

Modern Waste Management:

• 1/2 the U.S. cities are running out of landfill space• Industrialization and Urbanization• New and innovative programs are the only

solution• costly

Modern Trends: Integrated Waste Management

• Many modern methods involve moving waste from site to site, not disposing of it.– Disposal sites can produce significant air

pollution

• IWM emerged in the 80’s: management alternatives.

• IWM needs to be rethought to include materials management

Materials Management

• Part of Integrated Waste Management

• Their goal is zero production of waste• Incentives toward sustainability

• Removal of subsidies

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

“State of the art” landfill with a double liner of clay and plastic, a leachate collection system, and groundwater and vadose zone monitoring wells (Fig. 12.5)

Map view Cross section

Site selection for sanitary landfills

• Avoid:– siteing over aquifers– swampy areas– Floodplains– High water table

• Seek:– Siting 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 Landfillhttp://www.sandiego.gov/environmental-services/ems/index.shtml

Hazardous Chemical and Hazardous Chemical and Radioactive Waste Radioactive Waste

ManagementManagement

Don’t put down the drain or

in the landfill

Radioactive waste

• Differ from other hazardous chemical wastes– Half life:

• Uranium-238: T1/2 : 4.5 billion yrs

• Plutonium-239: T1/2 : 24,000 yrs.

• Strontium-90: T1/2 : 29 yrs

• Iodine-131: T1/2 : 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

• 1. Leaving it where it is• 2. Disposing of it in various ways

◦ 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 Projecthttp://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 3km) boreholes

• Subductive Waste Disposal