Energy Efficiency & Renewable Energy Management Centre 
Waste to Energy:
Rapid urbanization, industrialization, and change in life have resulted in the generation of enormous quantity of wastes in urban and industrial areas of country. Each year about 30 tonnes of municipal waste generated and about 4400 million cubic meters of liquid waste are generated. Most wastes are generated find their ways into land and water bodies without proper treatment, causing severe water pollution. They also emit greenhouse gases like methane and carbon di oxide, and add to air pollution. The problem caused by solid and liquid waste can be significantly mitigated through waste to energy technologies that will allow treatment and processing of waste before their disposal. These measures would reduce the quantity of waste, generate a substantial quantity of energy from them, and greatly reduce pollution of water and air. Various technologies options are available for setting up of waste to energy projects which are as follows:
1. Anaerobic digestion/ biomethanation : In this process, the organic fraction of the waste is segregated and fed into a closed container/digester which undergoes biodegradation in presence of methanogenic bacteria and anaerobic conditions, producing methane-rich biogas and effluent.
2. Combustion/incineration: In this process, wastes are directly burns in presence of excess air at high temperature, liberating heat energy inert gases and ash. Combustion results in transfer of 65%-80% of heat content of the organic matter to hot air, steam, and hot water. The steam generated, in turn, can be used in steam turbines to generate power.
3. Pyrolysis/gasification: Pyrolysis is a process of chemical decomposition of organic matter brought about by heat .in this process, the organic material is heated in absence of air until the molecule thermally breakdown to become a comprising smaller molecule (syngas). Gasification can also take place as a result of partial combustion of organic matter in presence of restricted quantity of oxygen or air. Te gas so produce is known as producer gas. The gas after cleaning is burned in internal combustion engine generator sets or turbines to produce electricity.
4. Landfill gas recovery: The waste dumped in a lanfilll become subjected over a period of time, to anaerobic conditions. As a result, its organic fraction slowly volatilizes and decomposes, leading to production of \’landfill ga’, which contain high percentage of methane which has a calorific value of about 4500 kcal/m3 , therefore it can be used for generating power through IC engines or turbines.