Waste Disposal

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Waste Disposal

• Chapter 16

Photo from Sandia National Laboratory, U.S.
Department of Energy
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Solid Wastes

• Major source of solid waste in U.S. are
• Agriculture (crops and animals) more than 50
• Mineral industry (spoils, tailings, slag, and
  other rock and mineral wastes)
• Municipalities (small amount of municipal waste)
• Industry (highly toxic)

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Municipal Waste Disposal

• Open Dumps unsightly, unsanitary, and smelly
• Sanitary Landfills alternate layers of
  compacted trash and a covering material
• In U.S. open dumps no longer tolerated
• Landfill design is important
• Barriers need to lock in toxins and chemicals
  must reduce leakage into the environment
• Important to control the migration of leachate
  out of the landfill
• Sites for sanitary landfills often controversial
• NIMBY, NIMFY, NIMEY, and NOPE laws apply

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Landfill and Leachate
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bathtub effect
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Remaining landfill capacity
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Incineration

• Partial solution to space problems faced by
  landfills
• Burning waste produces abundant carbon dioxide
  plus other toxic substances
• Recent technology have improved incinerators to
  burn hotter that breakdown complex toxic
  substances to less dangerous ones
• Expensive to operate and still produce a residual
  waste often toxic and require proper storage
• The considerable heat generated by an
  incinerator can be recovered and used

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Proportions of municipal waste
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Waste-to-energy incineration facility
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Ocean Dumping

• Ship board incineration, over the open ocean, and
  dumping residual waste into the ocean
• Similar to land-based incineration but at sea
• Incineration not 100 effective, residual toxic
  materials and chemicals dumped into the ocean
  will still pollute the ocean
• Ocean dumping without incineration still popular
  in many places around the world
• Very disastrous to local oceans where practiced
• A dumping site for one very high-volume waste
  product dredge spoils

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Dumping sediments with pollutants
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Reduce Waste Volume

• Less volume means less landfill space and slower
  filling of available sites
• Easier to Handle (Nontoxic) Organic Matter
• Treated nontoxic organic waste can be fed to
  swine or composted
• Recycling any reuse of waste reduces volume at
  landfills
• Recover recyclable waste by source separation
  separate waste into useful categories (wood,
  paper, plastics, various metals, ) at the users
  site
• Deposits on reusable material (glass, cans,
  containers, ) often attractive incentive
• Many applications to this idea yet unexplored

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Recycling Symbols
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Recycling
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Reduce Waste Volume

• Another options
• Recycle crushed pavement as new roadbed material
• Recycle steel into other useful objects
• Re-use bricks as footpaths
• Innovations has no limit here
• Definite up and coming new industry

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Municipal waste disposal
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Main generators of hazardous wastes
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Liquid-Waste Disposal

• Sewage and by-products of industrial processes
• Main Strategies
• Dilute and disperse
• Concentrate and contain
• Neither strategy is safe in long term
• Secure Landfills is it possible?
• Placing liquid-waste into sealed drums, and
  covering with impermeable lining material idea
  is to assure that the leachate will not migrate
• Deep wells inject deep into the crust
• Leachate not contained
• May act to lubricate faults
• Expensive and unsafe

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A secure landfill design for toxic-waste disposal
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Deep-well disposal for liquid wastes
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Other Strategiesfor liquid Waste diposal

• Incineration produces carbon dioxide
• Treatment by chemicals to breakdown or
  neutralized liquid waste is a possibility
• Generate a less toxic liquid or residue
• Would still require proper storage

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Sewage Treatment

• Septic Systems individual user-level treatment
• Settling tank solids separated and bacterial
  breakdown begins
• Leach field or absorption field liquid with
  remaining dissolved organic matter seeps out of
  porous pipes
• Soil microorganisms and oxygen complete the
  breakdown of the organic matter
• Soil permeability and field size are controlling
  factors

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Septic tank system
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Sewage Treatment

• Municipal Sewage Treatment
• 1. Primary treatment removal of solids from
  organic liquid waste
• 2. Secondary treatment bacteria and fungi act to
  dissolve and breakdown the organic matter
• 3. Tertiary or advanced treatment filtration,
  chlorination, and other chemical treatment may
  occur

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Primary, secondary, and tertiary stages of
municipal treatment
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Ghosts of Toxins PastSuperfund

• Disposal of identifiable toxic wastes in U.S. is
  currently controlled
• Congress has mandated and provided billions of
  dollars to control and clean-up toxic spills from
  the past
• Expensive
• Political dynamite

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The first 951 toxic-waste dump sites
Completed removals of Superfund, 1980-1990
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Radioactive Wastes

• Radioactive Decay unstable nuclei decay and
  produce energy
• Radioisotopes each have their own rate of decay
  measured in a half-life
• Half-lives of different radioisotopes vary from
  microseconds to billions of years
• The decay of a radioisotope can not be
  accelerated or delayed
• Energetic radioisotopes must be contained out of
  the environment for ever

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Effects of Radiation

• Alpha, beta, and gamma rays are types of ionized
  radiation given off by the decay of various
  radioisotopes
• Cancer, tumors, tissue burns, and genetic
  mutation can result due to exposure of high doses
  of radiation
• Large doses result in death
• Accidents have occurred
• Chernobyl and Three Mile Island

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Nature of Radioactive Wastes

• Radioisotopes with half-lives of a few years to
  hundreds of years present the most risk
• Radioactive enough to cause harm
• Persistent in the environment long enough to
  require management
• Some are toxic chemical poisons
• Levels of radioactive waste
• Low-level do not require extraordinary disposal
  precautions
• High-level require extraordinary precautions
  must be isolated from the biosphere with
  confidence for a long time

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Historical Suggestions for Storage

• Space
• Antarctic Ice
• Plate Tectonic Subduction Zones
• Seabed Disposal
• Bedrock Caverns for Liquid Waste
• Bedrock Disposal of Solid High-Level Wastes
• Multiple barrier concept

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Waste Isolation Pilot Plant (WIPP)

• Southeast New Mexico site for storage of
  transuranic wastes
• Opened March 26, 1999
• WIPP is located in bedded salt underlain by
  evaporites and overlain by mudstone
• Located 2150 feet below the surface in a dry and
  stable tectonic region
• Tectonic stable for over 200 million years

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Yucca Mountain

• Established by Nuclear Waste Policy Act of 1982
  establish a high-level disposal site in the west
• Yucca Mountain Attractive Characteristics
• 1.Rhyolitic tuff host rock
• 2. Arid climate
• 3. Low population density (but Las Vegas is 60
  miles to the southeast)
• 4. Low regional water table
• 5. Apparent geologic stability
• Geological studies were detailed and revealing

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