Solid Waste: solid materials discarded by society. generated by cities, manufacturing, etc.
 Municipal solid waste:  mostly paper, glass, plastics, metals, etc.
 Manufacturing solid waste:  practically anything.
 Radioactive solid waste:  byproduct of nuclear fission (energy, weapons materials)

Classification of Hazardous Waste
 1.  toxic: can cause health problems if high concentration or long exposure
      carcinogenic:  cancer causing.  example:  trichloroethylene solvent (TCE)
      mutagenic: creates genetic mutations.  ex: high level radioactive waste
      teratogenic: creates deformities. (thalidomide, sedative drug).
 2.  flammable:  catches fire easily.  example: gasoline, jet fuel, paint thinner
 3.  reactive:  chemically unstable, explosive and/or corrosive
        examples:  strong acids, nitroglycerine, industrial solvents
4.  explosive

 hazardous waste classified under RCRA: Resource Conservation Recovery Act
  establishes 504 hazardous wastes recognized by EPA, not all on this list
  states, counties and cities may have their own rules and regs too.

Waste "Management" and Disposal
    Landfills (aka dumps):   classic approach to waste management
        many landfills are former sand and gravel quarries, often aquifers; worst spot
        many landfills have no barrier (ex plastic liners) to waste transport in water
        many landfills contain toxic and hazardous wastes dumped deliberately

    Incineration (burning): heat in the presence of oxygen until combustion begins
      A.  incinerate as an end-stage disposal mechanism
           hospitals often have their own incinerators to burn biohazards, etc.
      B.  incinerate to generate hot water and/or electricity with steam turbines
         creates greenhouse gases (CO2, water vapor), toxic gases (ex: dioxin), etc.
         creates fly ash often rich in heavy metals, etc., must be disposed in landfill

    Radioactive Waste Storage:  must plan for 1000's of years, long half lives
         A) burial in hard rock underground caverns; B) seal in glass canisters

Recycling:  "today's waste is tomorrow's resource".  converting waste into products.
         example:  recycling of plastic bottles into plastic lumber for outdoor applications
    recycling the least environmentally beneficial approach to the waste problem
    reduce: don't use manufactured products in the first place, "consume less"
        least consumption of raw materials, energy, water, space, etc.
    reuse:  use the manufactured object again just like it is without modification
         ex A: reusing beverage bottles after washing and refilling with beverage
           ex B:  reusing beverage bottles as flower vase (different than initial use)
       no reformulation/modification means less energy, less materials, etc.
  recycling:  heavily promoted by government and businesses...............
   reformulating the object means using energy, materials, space etc.
   "recycling is big business' answer to the conservation movement"
 Seattle:  highest recycling rate of US major city, around 40-45%
 

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