Introduction [i]

Every year there is an estimated 30 million tonnes of solid waste and 4,400 million cubic meters of liquid waste generated the urban areas of India. The municipal solid waste (MSW) generation ranges from 0.25 to 0.66 kg/person/day with an average of 0.45 kg/person/day. In addition, large quantities of solid and liquid wastes are generated by industries. Most wastes that are generated find their way into land and water bodies without proper treatment, causing severe water pollution. They also emit greenhouse gases like methane and carbon dioxide, and add to air pollution. The problems caused by solid and liquid wastes can be significantly mitigated through the adoption of environment-friendly waste-to-energy technologies that will allow treatment and processing of wastes before their disposal. These measures would reduce the quantity of wastes, generate a substantial quantity of energy from them, and greatly reduce pollution of water and air.

Technology[ii]

Various technological options are available for setting up of waste-to energy projects. Some of these are described below.

Anaerobic Digestion/Biomethanation

In this process, the organic fraction of the waste is segregated and fed into a closed container (biogas digester). In the digester, the segregated waste undergoes biodegradation in presence of methanogenic bacteria and under anaerobic conditions, producing methane-rich biogas and effluent. The biogas can be used either for cooking/heating applications, or for generating motive power or electricity through dual-fuel or gas engines, low-pressure gas turbines, or steam turbines. The sludge from anaerobic digestion, after stabilization, can be used as a soil conditioner. It can even be sold as manure depending upon its composition, which is determined mainly by the composition of the input waste.

Combustion/Incineration

In this process, wastes are directly burned in presence of excess air (oxygen) at high temperatures (about 800 ºC), 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.

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 molecules thermally break down to become a gas comprising smaller molecules (known collectively as syngas).

Gasification can also take place as a result of partial combustion of organic matter in presence of a restricted quantity of oxygen or air. The gas so produced is known as producer gas. The gases produced by pyrolysis mainly comprise carbon monoxide (25%), hydrogen and hydrocarbons (15%), and carbon dioxide and nitrogen (60%). The next step is to ‘clean’ the syngas or producer gas. Thereafter, the gas is burned in internal combustion (IC) engine generator sets or turbines to produce electricity.

Landfill Gas recovery

The waste dumped in a landfill becomes subjected, over a period of time, to anaerobic conditions. As a result, its organic fraction slowly volatilizes and decomposes, leading to production of ‘landfill gas’, which contains a high percentage of methane (about 50%).It can be used as a source of energy either for direct heating/cooking applications or to generate power through IC engines or turbines.

Plasma arc

Plasma arc technology is a relatively new technology for disposal of wastes, particularly, hazardous and radioactive wastes. This technology is now being seen as an attractive option for disposal of MSW as well.

Potential in India[iii]

• Municipal Solid Waste: 17 MW
• Industrial Waste: 29.50 MW

Installed Capacity in India[iv]

• Municipal Solid Waste: 17 MW
• Industrial Waste: 29.50 MW

Potential for recovery of energy (MW) from urban wastes by state 

Table 2

Potential for recovery of energy from industrial wastes 

Waste generations trends in India   

 Projects in India[v]

 The Ministry of Non-Conventional Energy Sources is promoting setting up of Waste-to-Energy projects in the country through two schemes namely

i) National Programme on Energy Recovery from Urban and Industrial Wastes and 
ii) UNDP/ GEF assisted Project on Development of High Rate Biomethanation Processes as a means of Reducing Green House Gases Emission.

 A total of 27 waste to energy projects have been completed as on 31 March 2005.

 A few demonstration projects on urban wastes have been taken up by the MNES under the UNDP/GEF assisted project mentioned earlier. Three such projects are described below.

Projects based on Urban Waste

Projects based on Industrial Waste 

Waste to energy companies

The TIMARPUR- OKHLA Waste Management Company Pvt. Ltd's (TOWMCL)

The TIMARPUR- OKHLA Waste Management Company Pvt. Ltd's (TOWMCL) is venturing into integrated waste to energy project at Delhi. The project activity includes a proposal to set up a biomethanation unit for treatment of 50 tons per day (TPD) of segregated vegetable market waste and 6 million gallons per day (MGD) of sewage which would produce biogas use as fuel to a power plant. This will effectively manage the municipal solid wastes and utilize the high organic load of the wastewater generated from food processing industries and market yards to generate renewable energy.

Jeruz Energy Ltd.

Jeruz Energy Ltd. was formed by Indian origin with worldwide experience in high technology businesses. They have studied and dealt with a wide variety of technologies, products, and related services in the Clean Energy, Clean Water, and Clean Air Industries. Jeruz Energy Ltd.. has developed relationships and formed strategic alliances with major worldwide technology

Pyromex

In a 12 years' R&D program, Pyromex has found the ultimate solution to treat all types of waste without waste residues and without harmful emissions to the atmosphere and at the same time recover all valuable constituent of the waste at highly economic conditions.

Energy Developments Limited Private India Limited (EDL India)

Energy Developments Limited Private India Limited (EDL India) is a subsidiary of the Australian company, 12% of whose shares are held by the US-based Smith family's Brightstar Synfuel Corporation. It reports that till June 30, 2002, over the last 11 years, it had invested $148 million in the development of its gasification technology. The plant has been proposed at Perungudi dumpsite where the company has been leased a 15-acre plot of land for 15 years by the corporation. The dumpsite receives about 1,200 tonnes of waste per day. The company intends to dispose of waste and recover electricity through the company's gasification technology, which it calls a Solid Waste Energy Recycling Facility (SWERF). The company also claims to have a Materials Recovery Facility (MRF).

Research Centres

International Water Management Institute In the South Asia sub-region, International Water Management Institute has offices in India (Hyderabad and Delhi), Pakistan (Lahore) and Nepal (Katmandu), and has on-going activities in Bangladesh. IWMI's sub-regional office for South Asia is based at the ICRISAT campus in Hyderabad, India. With the goal of developing country-specific mitigation options, IWMI is conducting research on wastewater irrigation in India (Hyderabad), Pakistan (Faislebad), and Nepal (Kathmandu) to determine the risks and benefits of this expanding practice in the sub-region. The Institute is also looking at the challenges associated with groundwater and the implications of the water-energy nexus.

Apex Bodies

National Solid Waste Association of India (NSWAI)
Convener/Coordinator NSWAI-ENVIS
B-703, Customs Colony ‘A’
Military Road, Marol, Andheri(E),
Mumbai-400 059
Phone 91-22-29207577
Telefax 91-22-29202951

[i] http://mnes.nic.in/booklets/Book5-e.pdf (Introduction Page 9)

[ii] http://mnes.nic.in/booklets/Book5-e.pdf (Technology Options Page 10)

[iii] http://mnes.nic.in/booklets/Book5-e.pdf (Table 1 Page 5)

[iv] http://mnes.nic.in/booklets/Book5-e.pdf (Table 1 Page 5)

[v] http://mnes.nic.in/booklets/Book5-e.pdf ( Page 15)