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WASTE TRANSFORMATION
Why Transform Solid Waste?
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Efficient storage, handling and transport
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Reduce disposal cost
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Stabilize waste
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Destroy toxic elements (chemicals or biological entities)
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Generate electrical energy
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Re-use
Methods of Solid Waste transformation
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Physical Methods
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Chemical Methods
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Biological Methods
Physical Transformations
1. Component Separation or Sorting
• Done mechanically or manually, at source or at a transfer station
• Key process to recover recyclables and remove Haz waste components
2. Mechanical Vol. Reduction or Densification
• Reduces storage, transport and disposal costs
• Paper, cardboard, plastics, and aluminum cans are baled using balers
• Waste collection vehicles are equipped with compaction mechanisms
• Fireplace logs from recycled paper and cardboard (re-use)
3. Mechanical Size Reduction
• Makes waste more uniform and reduces the average size
• Shredding, grinding, and milling
• Tree mulcher (shreds trees into wooden chips for landscaping application)
• Tire shredder
• Shredding of organic waste improves efficiency of composting
Chemical Transformations
1. Combustion (or chemical oxidation)
• Combustion is carried out in the presence of enough air to oxidize the organic matter
• Key products are N2, CO2, H2O, O2, Ash, and Heat is generated (exothermic reactions)
• Used for waste to energy plants
2. Pyrolysis
• Thermal reactions in absence of oxygen
• Endothermic reactions (heat is sucked by the reaction)
• Organic fraction transforms into H2, CH4, CO2, trace gases, tar/oil, acetic acid, acetone, and char (carbon)
3. Gasification
• Partial combustion of carbonaceous fuel to generate combustible fuel gas rich in CO, H2, saturated hydrocarbons (CH4)
• Internal combustion engine can be used to burn the combustible fuel gas to generate energy
Biological Transformations
• Applicable only to organic fraction of waste
• The end product - compost is a humus like material used for soil conditioning applications or to produce methane gas
1. Aerobic Composting
• Decomposition of organic fraction of waste in presence of oxygen
• The rate of degradation is a function of these key factors: organic fraction in waste, temperature, moisture content, and available nutrients
• Key reaction products include: resistant organic matter (containing lignin), CO2, H2O, NH3, sulfates, and Heat
1. Anaerobic Digestion
• Decomposition of organic fraction of waste in absence of oxygen (an-aerobic)
• Key reaction products include: resistant organic matter, CH4 and CO2, H2S, NH3, sulfates, and Heat
• Odor issues due to formation of waste
•CH4 and CO2 equally constitute about 99% of total gas production
• Resistant organic matter is a sludge with relatively high water content. Hence, needs dewatering before disposal or transportation
INEWCORP'S MAIN TECHNOLOGIES FOR WASTE
