With rapid urbanisation taking place in our country, tackling of municipal solid waste especially in the metro cities has reached a dead end when land fill areas are no more available. The world over situation is no different, yet the problem gets solved, explains Ulhas Parlikar.
Current level of municipal solid waste (MSW) generation in the country is about 70 million TPA. The sustainable management of MSW demands that each constituent present in it is gainfully utilised and same is achievable by having proper segregation processes. This workable approach provides landfill free towns is depicted in Fig 1.
Towns of Madukkarai in Tamil Nadu, Vengurla in Maharastra, Ambukapur in Chattisgarh, etc. are the demonstrated examples of this concept of sustainable management of MSW in which each fraction of the segregated fraction of MSW gets gainfully utilised and there is no dump yard or landfill in the process in these towns. The SWM Rules, 2016 have included following provisions to achieve the desired level of segregation.
Segregation of dry, wet and domestic hazardous waste at source
Door-to-door collection
Setting up Material Recovery Facility (MRF) facilities to achieve following:
- Segregation of compostable material for sending it to composting facility or converting it into biogas
- Segregation of recyclables such as metals, plastics and glass for sending it to recycling facilities
- Segregation of inert materials to send it for filling in low lying areas/embankments etc.
Segregating the non-recyclable combustiblematerial called segregated combustible fraction (SCF) and sending it for use in following applications:
- Co-processing in cement kilns as alternative fuel and raw material or
- replacement of fossil fuel used by power plants or other applications within utilise
- fossil fuel in their operations or
- sending it to waste-to-energy (WTE) plant for generating electricity.
The municipal corporations of different towns and cities are moving towards implementing the above provisions in the rules appropriately. The management of compostable, recyclables and inert materials is pretty easy and has no difficulty in implementing.
In the sustainable management approach defined in Fig 1 the real challenge is with the management of SCF. This SCF is a mix of multi-layer Packaging (MLP) material, thin and single use plastics, rexin pieces, tyre and tube pieces, rubber pieces, thermocol, old or damaged shoes, chappals, old and torn clothes, contaminated paper, etc. As there are no takers for this material in the market market place, the same needs to be used for electricity generation in WTE plant or needs to be sent to cement kiln or power plant for co-processing.
Options of WTE and power plants
The option of waste to energy for this SCF fraction is difficult to implement in most of the towns and cities because the minimum implementable size of the WTE plant is 300 TPD and the cost of such a WTE plant is about Rs 100 crore. To generate 300 TPD of SCF, the population of the town has to be more than 50 lakh, SCF content in MSW should be around 15 per cent and the MSW generation rate should be 0.4 kg/capita/day. Barring a few metro cities, none of the towns and cities can meet these criteria. Therefore, the option of waste to energy is difficult to implement unless the SCF is pooled up from different adjacently located towns.
The utilisation of SCF in the power plant is not yet getting implemented and has concerns due to presence of >0.5 per cent chlorine in it. These concerns are on account of the likelihood of dioxins/furans and hydrogen chloride in the stack gases. There is need therefore to have some co-processing trials carried out in some of the power plants in the country to work out an appropriate protocol.
Capability of cement industry
The best option therefore is cement kiln co-processing and is substantially workable on account of following features.
- The cement plant is already existing.
- Most of the cement plants have co-processing facility already set up on their kiln system.
Hence most of such cement plants are ready to utilise the refused derived fuel (RDF) meeting their acceptability criteria. From the 70 million TPA of MSW, appropriately 10 million TPA of SCF can get generated. This can be suitably converted into cement grade RDF and can be sustainably utilised in the cement kiln as alternative fuel and raw material through co-processing.
The current clinker production is at a level of about 250 million TPA, the TSR achievable by the industry with this RDF would range in between 12 to 15 per cent, which is easily feasible without getting into concerns of chlorine saturation.
Acceptable RDF grade to cement industry
The expert committee constituted by the Ministry of Housing and Urban Affairs (MoHUA) has proposed three grades of RDF for use in cement industry. Grade – I and Grade – II can be utilised by cement industry as such and Grade – III can be utilised by it after blending it with some other AFR materials. These RDF grades can be manufactured from the non-recyclable segregated combustible fraction (SCF) that gets generated from MSW.
The manufacture of these RDF grades can be done after setting up the required facility. These include facilities for quality assessment, blending, shredding, bailing, storage, etc. It is desired that RDF producers interact with cement plants to produce the material having desired quality and enter into a suitable long term techno-commercial agreement with them. This facility can be set up near the SCF generation site or at the cement plant. It can be set up and operated by a third party waste processor or also by the cement plant as depicted in Fig 2.
Win-win considerations in the sustainable management of SCF For having ensuring a successful business model, it is important to have a win-win consideration in case of each of the stakeholder. There are three stakeholders in the process. They are municipal corporation, waste processor and cement plant. Fig 3 provides the cost and benefits associate with each of these stakeholders.
Following win-win considerations should be noted from Fig 3:
- Cement plant: The price of RDF should be reasonably lower than the cost of coal after accounting for higher fuel consumption and production loss.
- Waste processor: Sum of the (i) tipping fee earned from municipal corporation and (ii) RDF price received from cement plant should be reasonably more than sum of (i) processing cost of converting SCF to RDF, (ii) transportation cost of SCF from Municipal Corporation to its facility and (iii) transportation cost of RDF from its facility to cement plant.
- Municipal corporation: The SCF should get sustainably managed without the need to build dump yard or land fill for the same. Further, the proportionate portion of the taxes collected by it for management of MSW should be more than or equal to the tipping fee paid to the waste processor for the sustainable management of SCF.
Challenges and feasible solutions
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A justifiable consideration of the administration towards this solution. Currently, the major consideration of the administration is revolving around the WTE solution which is unlikely to get implemented due to the techno-commercial constraints mentioned above. The co-processing solution is more attractive from both technical and commercial considerations.
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Cost involved in setting up RDF processing facilities and extending some of the relevant fiscal policies towards this solution. The central government and state governments extend grants in setting up the projects for management of MSW. It is desired that these grants should also get extended to setting up the facilities for production of cement grade RDF.
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Cost of transportation of SCF from Municipal Corporation to waste processor and cost of RDF from the waste processor to cement plant. Considering that the overall SCF generation in the country will be about 10 Million TPA and average transportation cost of transporting SCF from municipal corporation to SCF processing facility is Rs 400/t, the overall cost of transportation works out to Rs 400 crore per year. Considering that RDF produced from SCF will be 7 million TPA and the average cost of transportation of RDF from processing facility to cement plant is Rs 1,500 per tonne, the total transportation cost works out to Rs 1,050 crore. Hence, put together the amount works out to Rs 1,450 crore.
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This figure of Rs. 1450 Crores per year is for the management of the entire non-recyclable combustible fraction getting generated in the country and avoids dump yards and landfill implementation country-wide.
Recommendations
It is suggested therefore that following actions be taken up by the Government to solve this huge problem of SCF waste management and dump yard creation faced in the country.
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Formulate a RDF mission to directly coordinate the required actions through municipal corporations, MSW management companies, RDF manufacturing companies and cement plants.
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Extend the existing fiscal benefits of MSW projects to RDF production projects also.
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Encourage use of RDF in cement kilns through feasible fiscal policies.
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Encourage setting up of RDF facilities across the towns and cities of the country by including them in the tendering process.
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Establish mechanism to deal with the transportation cost management of SCF and RDF as elaborated above through an appropriate central and state level budgeting process.
Conclusion
The current status of RDF usage is same as that of fly ash usage in the cement manufacture in the 90s. The cement industry has grown mature over past decades and is utilising now about 50 million TPA of fly ash. This is because of the win-win policy that the fly ash mission had promoted during the initial days. It is clear from the fly ash example that if RDF is seen as an accessible and acceptable material from the techno-commercial angle, the entire cement industry would implement the required facilities at its plant and would undertake co-processing of RDF to its maximum levels.
This RDF use in cement plant will facilitate following.
- Reduction in land filling/dump yard space
- Reduced GHG emissions
- Eliminating the dump yards and associated environmental issues and
- Conservation of reasonable quantum of fossil resources such as coal, limestone, iron ore, bauxite and silica that are being utilised currently in the cement manufacture.
ABOUT THE AUTHOR:
The article is authored by Ulhas Parlikar. He can be contacted at: Mob: +91 99675 81975 or Email: ulhas@parlikar.com