Waste to Energy for Integrated Waste Management in India

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Role for Waste to Energy in Integrated Indian Waste Management17 January 2012

If the Indian Waste to Energy industry can exhibit self-responsibility in emissions control, it could established itself as a solution to a crisis and lead the way for reforms in implementation of regulations across all other industries, according to a recent study.

The study - sponsored by the Waste-to-Energy Research and Technology Council (WTERT), and conducted by Ranjith Kharvel Annepu - examined the present status of waste management in India, its effects on public health and the environment, and the prospects of introducing improved means of disposing Municipal Solid Waste (MSW) in India.

The investigated both informal and formal recycling, aerobic composting and mechanical biological treatment, small scale biomethanation, Refuse Derived Fuel (RDF), Waste to Energy (WtE), and landfill mining (or Bioremediation).

The main objective of the study was to find ways in which the enormous quantity of solid waste India currently disposes of on land could be reduced by recovering materials and energy in a cost effective and environmental friendly manner.

According to the author, a lack of data and inconsistency in existing data is a major hurdle while studying developing nations. In his report Annepu attempted to fill this gap by tabulating the per capita waste generation rates and wastes generated in 366 Indian cities that in total represent 70% of India's urban population.

The study claimed that this is the largest existing database for waste generation in individual cities in India.

Estimations made by extrapolating this data puts the total MSW generated in urban India at 68.8 million tons per year (tpy) or 188,500 tons per day (tpd). The data collected indicate a 50% increase in MSW generated within a decade since 2001.

According to the research, if the trend continues, urban India will generate 160.5 million tpy (440,000 tpd) by 2041 and over the next decade some 920 million tonnes of MSW that needs to be properly managed.

The study finds that the composition of urban MSW in India is 51% organics, 17.5% recyclables (paper, plastic, metal, and glass) and 31% of inerts. The moisture content of urban MSW is 47% and the average calorific value is 7.3 MJ/kg (1745 kcal/kg).

The composition of MSW in the North, East, South and Western regions of the country varied between 50-57% of organics, 16-19% of recyclables, 28-31% of inerts and 45-51% of moisture. The calorific value of the waste varied between 6.8-9.8 MJ/kg (1,620-2,340 kcal/kg).

The current situation

The study also found that in the city of Mumbai alone, the open burning of solid wastes and landfill fires emit nearly 22,000 tonnes per year of pollutants into the air. These pollutants include Carbon Monoxide (CO), Hydrocarbons (HC), Particulate Matter (PM), Nitrogen Oxides (NOx) and Sulfur Dioxide (SO2) plus an estimated 10,000 TEQ grams of dioxins/furans.

According to the research, since open burning happens at ground level, the resultant emissions enter the lower level breathing zone of the atmosphere, increasing direct exposure to humans.

The author also said that he has observed that the role of the informal sector in Solid Waste Management (SWM) in developing nations is increasingly being recognised, and claimed that there is worldwide consensus that the informal sector should be integrated into the formal system and there are numerous initiatives working with such goals.

The report estimated that every ton per day of recyclables collected informally saves the urban local body Rs24,500 ($500) per year and avoids the emission of 721 kg of carbon dioxide per year.

According to the research, there is no sufficient information on the performance of India's MSW composting facilities. However, an important observation made during this study is that the compost yield from mixed waste composting facilities (MBTs) is only 6-7% of the feed material. Up to 60% of the input waste is discarded as composting rejects and landfilled, the rest consists of water vapour and carbon dioxide generated during the composting processes.

Furthermore, the study found that the compost product from mixed wastes was f of very low quality and contaminated by heavy metals. The majority of the mixed waste compost samples fell below the quality control standards for total potassium, total organic carbon, total phosphorus and moisture content; and exceeded the quality control limits for heavy metals (lead, Pb, and chromium, Cr).

If all MSW generated in India in the next decade were to be composted as mixed waste and used for agriculture, it would introduce 73,000 tonnes of heavy metals into agricultural soils, according to the report's author.

The study also found that the calorific value of some composting rejects is as high as 11.6 MJ/kg (2770 kcal/kg). This value is much higher than the minimum calorific value of 7.5 MJ/kg (1,790 kcal/kg) recommended for economically feasible energy generation through grate combustion WtE.

According to the author, this data is important, considering the notion that the calorific value of MSW in India is not suitable for energy generation. Therefore, the residues of mixed MSW composting operations could be utilised for RDF production, or directly combusted in a WtE plant.

Furthermore, the report found that landfill gas (LFG) recovery has been shown to be economically feasible at seven landfills located in four cities, Delhi, Mumbai, Kolkata and Ahmadabad. Development of these seven LFG recovery projects will result in an overall GHG emissions reduction of 7.4 million tonnes of CO2 equivalents.

One of these landfills, the Gorai dumpsite in Mumbai, was capped in 2008 for capturing and flaring LFG. This project alone will result in an overall GHG emissions reduction of 2.2 million tonnes of CO2 equivalents by 2028.

Assuming a Business as Usual scenario (BaU), the author claimed that by the end of the next decade, India will generate a total of 920 million tonnes of MSW, landfill or openly dump 840 million tonnes of it and produce 3.6 million tonnes of mixed waste compost. It will also produce 33.1 million tpy of potential RDF in the form of composting rejects that will also be landfilled.

The study also found that in 2011, due to inadequate separation, India would landfill 6.7 million tonnes of recyclable material which could have been used as secondary raw materials in manufacturing industries.

A further 9.6 million tonnes of compost, which could have been used as a fertiliser supplement, would be landfilled due to the absence of source separation and enough composting facilities.

In addition, according to the study 58 million barrels of oil energy equivalent in residues of composting operations that could have been used to generate electricity and displace fossil fuels in RDF co-combustion plants or WtE power plants would also be landfilled due to the absence of WtE facilities, and proper policies and pollution control regulations for co-combustion of MSW in solid fuel industries.

Waste to energy proposals IndiaJoined up solid waste management proposals

The report proposed a waste disposal system which includes integrated informal recycling, small scale biomethanation, MBT and RDF/WtE.

Informal recycling can be integrated into the formal system by training and employing waste pickers to conduct door-to-door collection of wastes, and by allowing them to sell the recyclables they collected. Waste pickers should also be employed at material recovery facilities (or MRFs) to increase the percentage of recycling.

The study further proposed that single households, restaurants, food courts and other sources of separated organic waste should be encouraged to employ small scale biomethanation and use the biogas for cooking purposes.

Use of compost product from mixed wastes for agriculture should be regulated. It should be used for gardening purposes only or as landfill cover.

Rejects from the composting facility should be combusted in a waste-to-energy facility to recover energy. Ash from WtE facilities should be used to make bricks or should be contained in a sanitary landfill facility.

According to the author, such a system could divert 93.5% of MSW from landfill and increase the life span of a landfill from 20 years to 300 years. It would also decrease disease, improve the quality of life for urban Indians, and avoid environmental pollution.

Conclusions

The study concluded that two decades of economic growth since 1990 has changed the composition of Indian wastes, and that the quantity of MSW generated is increasing rapidly due to increasing population and change in lifestyles. Land is scarce and public health and environmental resources are precious.

The current SWM crisis in India should be approached holistically - while planning for long term solutions, focus on the solving the present problems should be maintained.

The Government of India and local authorities should work with their partners to promote source separation, achieve higher percentages of recycling and produce high quality compost from organics.

The study further concluded that materials and energy recovery from wastes is an important aspect of improving SWM in India. It not only adds value to SWM projects and makes them economically feasible but is also more sustainable.

Recycling, composting and WtE are integral parts of the solution and they are all required - none of them can solve the India's SWM crisis alone.

MBT for the windrow composting of mixed wastes should be used to separate wastes. Such separation at a later stage allows for managing the wastes better. Compost from such a facility should be used for cash crops/ or lawns or as landfill cover instead of for food crops.

Rejects from composting should be combusted to produce energy and reduce their volume. Only the ash from the WtE plants or co-combustion facilities should be landfilled.

If Indian WtE industry can exhibit self-responsibility in emissions control with constant emissions monitoring, and reporting and can feedback the results into a loop of self-improvement, it will lead the way for reforms in implementation of regulations across all other industries.

According to the study, if this were to happen the WtE industry could also establish itself as a solution to a crisis, a source of comfort to more than a billion people and inspiration to a huge industrial sector, rather than being perceived by some as another problem to fight against.

The copy of the full study is available from the Waste-to-Energy Research Council's website or by clicking HERE


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