Incineration, MSW Combustion
I.   Introduction (MSW combustion)
  1. Definition
    1. Combustion - a process of burning, resulting from the rapid oxidation of substances
    2. Used for municipal solid wastes, industrial (hazardous) waste, sludges, fossil fuel
    3. Typically operated with excess air (oxygen supply > combustion stoichiometry)
  2. Advantages
    1. Volume and weight reduced (approx. 90% volume and 75% weight reduction)
    2. Waste reduction is immediate, no long term residency required
    3. Destruction in seconds where LF potentially requires 100s of years
    4. Incineration can be done at generation site (ex. medical waste incinerators)
    5. Air discharges can be controlled (low health risk)
    6. Ash residue is usually non-putrescible, sterile, inert
    7. Small disposal area required
    8. Cost can be offset by heat recovery/ sale of energy
  3. Disadvantages
    1. High capital cost
    2. Skilled operators are required (particularly for boiler operations)
    3. Not all material are incinerable (noncombustable solids)
    4. Some material require supplemental fuel
    5. Public disapproval
      1. Risk imposed rather than voluntary
      2. Incineration will decrease property value (perceived not necessarily true)
      3. Distrust of government/industry ability to regulate
  4. History
    1. Late 1960s - 300 plants in the US (capacity of 30x106 tons/yr)
    2. 250 closed between 1965-1980 as a result of Clean Air Act regs (non-compliance)
    3. 1970’s source separation and mechanical separation (trommel, screens, hammermills, conveyors, magnets, air classifiers ) used to produce refuse derived fuel (RDF) to be fired in conventional coal fired boilers, by 1980 all but one closed due to material handling problems.
    4. With RCRA’s emphasis on recycle, materials handling equipment better, more effective pollution control equipment available, better understanding of combustion technology, LF siting problems:
      1. 1983 - 50 Municipal Waste Combustion (MWC) @ 76. million tons/yr
      2. 1986 - 81 MWC @12 million tons/yr
      3. 1990 - 168 MWC @31 million tons/yr
      4. 1991 - 176 MWC (137 with energy recovery) @31.4 million tons/yr, producing enough electricity to power 1.2 million homes
      5. 1992 - 190 MWC, 142 Waste To Energy (WTE) @33.6 million tons/yr capacity in 34 states
      6. 1993 -
        1. 16% of waste disposed in incinerators
        2. 100,000 tpd
        3. Power 1.3 million homes
        4. 164 MWC, 125 WTE
        5. 7 under construction, 37 planned
      7. 1994
        1. 15.5% of waste disposed in incinerators
        2. 89,000 tpd
      8. 2000 - anticipated that 20% of MSW will be combusted
      9. Florida combustion capacity highest in nation
      10. Future
        1. Some forms of RCRA reauthorization have called for a moratorium on MWC, expensive, strong market for recyclables, Clean Air Amendment (CAA) impact
        2. Expect recent rate increase to drop over next few yrs.; limited $, lack of project support, regulations unclear

 
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