Environmental Geology Spring 2010 – Text Notes

Waste Disposal and Management:

How much do we produce?  Approximately 3.2 tons/person/yr in U.S. (not including dredge materials).

Solid waste Sources: Looked at pie chart: mineral extraction and processing 38%; animals 39%; crops 14%; municipalities 5%; industry 3%.

Public Perception of Waste Management: NIMBY – not in my back yard; LULU – locally unavailable land use.

Goals: Three R’s: Reduce, Reuse, Recycle

Waste Reduction: increase lifespan of product; better packaging; decrease consumption (That’s Just Un-American!!!); reduce volume of products (smaller cars).

Recycle: Take components from an old product to make a new product; must have suitable markets to be successful.

Reuse: Use the product more than once; reuse in another plant process or household application

Municipal Solid Waste:
Composition: Percent by Weight: packaging 33%, nondurables 27%; yard waste 18%; durables 14%; food waste 7%; other 1%.

Percentage of garbage: by volume paper 35%; plastics 20%; ferrous metals 9%; glass 1%; other 35%

Methods of disposal:

On-site:
Garbage disposal (actually just converts to liquid stream and sends to waste water treatment plant).
Burn
Bury in back yard.
Composting

Sanitary Landfill:
Early days designed to control disease vectors (primarily rodents)
Deposit refuse, compact refuse, cover refuse

This has changed in the last 20 years or so to include this process along with low permeability liners, leachate detection and collection systems, and groundwater and surface water monitoring systems.
Classes of Landfills
Class I: no leachate discharge to useable water, no inundation or washout, impermeable liner less than 0.3 cm/yr.
Class II: site overlies or adjacent to useable water, artificial barriers may be needed (liners), permeability of liners should be less than 30 cm/yr.
Class III: not adequate protection of groundwater or surface water; filling of areas such as pits, quarries, etc.; inert materials such as benign construction wastes.

Some Problems with Landfills:
Stabilization to volume reduction which may be as much as 30% of total volume; results in cracks, sag ponds, and potential for increased infiltration to waste cells.

Gas generation: primarily methane – may be captured and used as energy source as is done in the Los Angeles area where over 50,000 homes are heated by this energy source.

Leachate: contains a variety of contaminants depending on what was disposed in the facility.

Landfill regulation falls under EPA at the Federal level and the Arkansas Department of Environmental Quality at the State level.  Laws governing the regulation of landfills are included in the Resource Conservation and Recovery Act (RCRA).
Landfills may not be located in the following areas
Floodplains
Wetlands
Unstable land
Earthquake fault zone
Near airports

Incineration:
Requires less space
Very high temperatures break down most compounds to CO2 and H2O
Still produces byproduct (ash) that may contain some contaminants.
Expensive to operate
However, they can produce electricity

Accounts for:
67% of waste disposal in Japan
60% in Sweden
80% in Switzerland
6% in U.S.

Ocean Dumping:
Was common, now becoming unacceptable, primarily due to legislation
Looked at case study of New York garbage barge from 1987

Hazardous Waste (HW)
Primary generator (chemical industry 79%); petroleum industry (7%); metal industry (2%); other (12%)

Methods of disposal for HW: surface disposal (drums, impoundments); landfills; deep well injection

Radioactive Waste:
High Level Waste: spent fuel rods; discarded warheads; transuranic waste
Low Level Waste: all other radioactive waste including such things as swabs, tools, gowns, etc.

Currently low level waste is buried at about 15 locations in Washington, Nevada, Kentucky, South Carolina, and New York.

Low Level Waste compacts formed in 1980’s (seven nationwide).  Arkansas belongs to compact with Kansas, Nebraska, and Oklahoma.  Proposed disposal site is in north-central Nebraska.  To date, no waste has been disposed at any of the low level waste compact sites.

Low level waste sites are designed to hold the waste without causing environmental problems for a period of 300 years.

High Level Radioactive waste is currently stored temporarily on-site and at several major sites throughout the U.S.

Problem is degree and longevity of radioactivity associated with this waste.

Disposal options:
1.    Rocket to deep space or the sun; expensive, potential for serious accident
2.    Continue Present storage: not a permanent solution
3.    Place in subduction zones; rate of plate motion is slow; too much uncertainty about subduction process; technical problems getting waste into trenches
4.    Place in polar ice caps; heat would melt ice and canisters would sink to rock surface; insufficient knowledge of global climate change over the long-term; insufficient knowledge of ice flow
5.    Place in salt mines; subject to solution; salt flows much like ice and would encapsulate the waste
6.    Place in stable, low permeability rock units; this is the method Congress has selected; waste will be stored at the Yucca Mountain facility in Nevada.

Criteria for disposal:
•    Save isolation for 250,000 years (Is this unrealistic or what!!!).
•    Safe from sabotage (not likely in this day and age, especially given the time frame).
•    Safe from natural disasters
•    Noncontaminating to natural resources (this one may actually prove to be the easiest)
•    Geologically stable area
•    Fail-safe handling and transport mechanism