Combustion or Incineration
- It is direct burning of wastes in the presence of excess air (oxygen) at high temperatures
(about 800 C). - It results in conversion of 65%-80% of heat content of organic matter into hot air, steam and hot water.
- The steam generated can be used in steam turbines to generate power.
Biomethanation or Anaerobic Bigestion
- In this, the organic waste is segregated and fed into a biogas digester.
- The waste undergoes biodegradation under anaerobic conditions to produce methane rich biogas.
- The so produced biogas can be used for cooking, heating, generating electricity etc.
- The sludge can be used as a manure depending on the composition of the input waste.
- It is chemical decomposition of organic matter through heat.
- The organic matter is heated in the absence or restricted supply of air till it breaks down into smaller molecules of gas (known collectively as syngas).
- Syngas so produced is known as producer gas which constitutes carbon monoxide (25%),hydrogen and hydrocarbons(15%), carbon dioxide and nitrogen(60%).
- The producer gas is burnt in internal combustion (IC) generator sets or turbines to produce electricity.
Landfill Gas Recovery
- In this the waste slowly decomposes to produce “Landfill gas”.
- This gas consists of high percentage of methane (approximately 50%) and has a high calorific value of about 4500kcal/cubic meter.
- It can be used for heating cooking and generating power.
Plasma Arc
- A relatively new technology for disposal of wastes, particularly, hazardous and radioactive wastes.
- Since it involves nearly complete destruction of waste while producing energy, it is less polluting.
- It does not produce oxides of nitrogen and sulphur and makes toxic ash left in the process easier to handle.
- However, the technology is costly and has not been tried in India.
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