METHODS OF SOLID WASTE DISPOSAL



DISPOSAL OF SOLID WASTE

Method of solid waste disposal are as below:

  • Open burning
  • Dumping into the sea
  • Sanitary Landfills
  • Incineration
  • Composting
  • Ploughing in fields
  • Hog feeding
  • Grinding and discharging into sewers
  • Salvaging
  • Fermentation and biological digestion

Open burning

Not an ideal method in the present day context

Dumping into Sea

  • Possible only in coastal cities
  • Refuse shall be taken in barges sufficiently far away from the coast (15-30 km) and dumped there
  • Very costly
  • Not environment friendly

Sanitary Landfilling

  • Simple, cheap, and effective
  • A deep trench (3 to 5 m) is excavated
  • Refuse is laid in layers
  • Layers are compacted with some mechanical equipment and covered with earth, levelled, and compacted
  • With time, the fill would settle
  • Microorganisms act on the organic matter and degrade them
  • Decomposition is similar to that in composting
  • Facultative bacteria hydrolyze complex organic matter into simpler water soluble organics
  • These diffuse through the soil where fungi and other bacteria convert them to carbon dioxide and water under aerobic conditions
  • Aerobic methanogenic bacteria utilize the methane generated and the rest diffuses into the atmosphere
  • Too much refuse shall not be buried – fire hazard
  • Moisture content – not less than 60% for good biodegradation
  • Refuse depth more than 3m – danger of combustion due to compression of bottom layers – hence should be avoided
  • Refuse depth is generally limited to 2m
  • Temperature in the initial stages of decomposition – as high as 70 degree C – then drops
  • Reclaimed areas may be used for other uses

Engineered Landfills

  • Bottom of the trench is lined with impervious material to prevent the leachate from contaminating groundwaters
  • A well designed and laid out leachate collection mechanism is to be provided
  • Leachate so collected is treated and then disposed off

DISPOSAL OF SOLID WASTE

Figure: A Typical Sanitary Landfill

DISPOSAL OF SOLID WASTE

Figure: A Typical Sanitary Landfill